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The article presents the issues related to load-power sharing in direct-current grid and a novel control method has advantages over known solutions. Unlike many similar-sounding papers, this article shows an attempt at creating fully controllable non-isolated system that allows for load-power sharing between a permanent magnet alternator equipped with machine-side converter (MSC) and a dual active bridge (DAB) tied to batteries or supercapacitor. The current-based load-power sharing is an essential feature of parallel-connected direct-current generators, and all types of voltage sources, in this way are contributing power to the system. To keep the optimal efficiency of the alternator, the rotational speed changes rely on proper mapping of the driving combustion engine. System components include a self-excited synchronous generator (SESG), operating at variable shaft speed, as well as batteries and supercapacitors that provide electricity for sudden electrical-load changes on the distribution grid. The core of the presented system is in a power-distribution method that consists of a programmed-controller structure allowing precise current distribution. A novelty of the proposed method is the use of a cascaded system of current and DC voltage regulators that allows for precise power-distribution control. In contrast with previously presented solutions, the proposed system allows for fast and accurate control of currents, loading parallel-connected DC voltage sources for wide-range generator speed changes. In the presented solution, both converters have been equipped with Schottky diodes, preventing the flow of equalizing currents between closed transistors in the parallel mode of operation. An experimental test-stand of the described system is presented with its theoretical basis and experimental results. [ABSTRACT FROM AUTHOR]

Currently, power trains based on an Open-End Winding Induction Machine fed by a Dual Inverter (DI-OEWIM) are attracting a great deal of interest in various modern industrial applications. However, applying symmetrical control to this system (DI-OEWIM), which is symmetrical in nature, will lead to malfunction. Therefore, the objective of this paper is to explore the influence of asymmetric control on the performance of this system. The principle of this study is to create an asymmetrical control by integrating a phase-shift angle in the Space Vector Pulse Width Modulation (SVPWM) strategy. We then evaluate the impact of these angles on various performances, such as the Total Harmonic Distortion (THD), power losses, Common Mode Voltage (CMV), Zero-Sequence Voltage (ZSV), rotation speed and torque ripple of this system. This study was carried out in the Matlab/Simulink environment and was validated experimentally using the dSPACE 1104 board. The results show that the different angles have significant effects on the overall performance of this system. [ABSTRACT FROM AUTHOR]

In this paper, a wireless potentiostat code-named ElectroSense, for interfacing of wearable electrochemical biosensors, will be presented. The system is devoted to non-invasive monitoring of glucose in wearable medical applications. Differently from other potentiostats in literature, which use digital-to-analog converters (DACs) as discrete components or integrated in high-end microcontrollers, in this work the pulse width modulation (PWM) technique is exploited through PWM-DAC approach to generate signals. The ubiquitous presence of integrated PWM peripherals in low-end microcontrollers, which generally also integrate analog-to-digital converters (ADCs), enables both the generation and acquisition of read-out signals on a single cheap electronic device without additional hardware. By this way, system's production costs, power consumption, and system's size are greatly reduced with respect to other solutions. All these features allow the system's adoption in wearable healthcare Internet-of-things (IoT) ecosystems. A description of both the sensing technology and the circuit will be discussed in detail, emphasizing advantages and drawbacks of the PWM-DAC approach. Experimental measurements will prove the efficacy of the proposed electronic system for non-invasive monitoring of glucose in wearable medical applications. [ABSTRACT FROM AUTHOR]

Electrically powered rail transport is constantly increasing in order to meet the high demand for people and cargo transportation, whether with high-speed trains, subways, suburban trains, or electric tramways. In these types of applications, power electronics solutions such as integrated and efficient converters with multiple functionalities are highly desirable. Among these converters, one family stands out for its ability to generating multiple output terminals with reduced number of switches, namely, the nine-switch converter. Therefore, this paper proposes a multiport converter solution based on the nine-switch converter topology that integrates multiple functionalities with a reduced switch count. The converter, responsible for the power drive of the electric tramway, is exclusively powered by a battery. Moreover, it presents a strategically connected passive filter that provides a low-impedance path for high-frequency currents, avoiding leakage of the current circulation in the induction motor. Its phase-shift pulse-width modulation is capable of reducing the high-frequency components of the current delivered by the battery. The energy storage system is designed to optimize the system capacity based on the known real load profile of a public tramway, with a maximum power of 532.1 kW. The control system is designed and applied considering the battery as the energy source. Simulations were performed in the Matlab/Simulink environment to validate the proposed system, along with experiments using a reduced-scale prototype controlled by the dSPACE platform. The results present the converter's proper operation with integration of the source and AC load, presenting improved features compared with conventional solutions in terms of reduced leakage of the current circulation from the AC load and reduced battery current ripple. [ABSTRACT FROM AUTHOR]

This paper investigates the development of pulse width modulation (PWM) schemes for three-phase quasi-Z-source inverters (qZSIs). These inverters are notable for their voltage boost capability, built-in short-circuit protection, and continuous input current, making them suitable for low-voltage-fed applications like photovoltaic or fuel cell-based systems. Despite their advantages, qZSIs confront challenges such as increased control complexity and a larger number of passive components compared to traditional voltage source inverters (VSIs). In addition, most existing PWM schemes for qZSIs lack the capability for independent control of the amplitude modulation index and duty cycle, which is essential in closed-loop applications. This study introduces innovative space-vector PWM (SVPWM) schemes, addressing issues of independent control, synchronization, and unintentional short-circuiting in qZSIs. It evaluates several established continuous and discontinuous PWM schemes, and proposes two novel decoupled SVPWM-based schemes that integrate dead time and in which the shoot-through occurrence is synchronized with the beginning of the zero switching state. These novel schemes are designed to reduce switching losses and improve qZSI controllability. Experimental validation is conducted using a custom-developed electronic circuit board that enables the implementation of a range of PWM schemes, including the newly proposed ones. The obtained results indicate that the proposed PWM schemes can offer up to 6.8% greater efficiency and up to 7.5% reduced voltage stress compared to the closest competing PWM scheme from the literature. In addition, they contribute to reducing the electromagnetic interference and thermal stress of the related semiconductor switches. [ABSTRACT FROM AUTHOR]

High-performance overmodulation strategies for voltage source inverters (VSIs) can further broaden the operation range of machines. Among them, Space Vector Pulse Width Modulation (SVPWM) is worth researching as it performs well in digital implementation. This paper presents a detailed comparison of various SVPWM overmodulation strategies and analysis of their performance. It firstly briefly elaborates fundamental laws of two subspaces of five-phase VSIs. Then, it focuses on several overmodulation strategies. Their corresponding basic principles and main characteristics are researched, and conclusions are given. In addition, differences and relationships between them are proved and summarized. Lastly, comparative simulations and experiments were carried out and verify that in the overmodulation region, the output voltage distortion degree increases with the increase in modulation ratio, and strategies with more control degrees of freedom (CDFs) are capable of better controlling the third harmonic subspace, which means that higher-quality output voltage waveforms would be obtained. [ABSTRACT FROM AUTHOR]

The paper proposes a nonlinear controller called dual super-twisting sliding mode command (DSTSMC) for controlling and regulating the rotor side converter (RSC) of multi-rotor wind power systems that use doubly-fed induction generators. It was proposed that this controller be developed as an alternative to the direct power control (DPC), which makes use of a pulse width modulation (PWM) strategy to regulate the RSC's functioning. Overcoming the power/current quality issue with the proposed technique (DPC-DSTSMC-PWM) is characterized by great robustness and excellent performance. The designed strategy was contrasted with the standard method of control and other methods already in use. So, the unique proposed control strategy's robustness, performance, efficiency, and efficacy in enhancing system characteristics were tested and validated in Matlab/Simulink. In both tests, the proposed method resulted in significant improvements, reducing active power ripples by 83.33%, 57.14%, and 48.57% in the proposed tests. When compared with the traditional regulation method, the reduction rates of reactive power ripples are 64.06%, 52.47%, and 68.7% in the tests. However, in contrast to the conventional method, the proposed tests showed a decrease of between 72.46%, 50%, and 76.22% in the value of total harmonic distortion (THD) of the provided currents. These ratios show how effective the proposed plan is in ameliorating and enhancing aspects of the energy system. [ABSTRACT FROM AUTHOR]

The silicon carbide (SiC) inverter brings great advantages to the motor drive systems of new energy vehicles; however, severe challenges to the bearings also happen. The high dc bus voltage and switching frequency of SiC inverter can increase the discharge frequency and energy when the bearing grease film collapses. As a result, the bearing suffers severe electric corrosion, and the service life of the motor drive system can be shortened. In this paper, the characteristics of common-mode voltage and bearing voltage are analyzed, firstly under space vector pulse width modulation (SVPWM). After that, the common-mode equivalent circuit model of the motor drive system is established. The frequency characteristics of bearing voltage are revealed, and the safe working area is determined. Then, the frequency characteristics of bearing voltage and current are verified based on IGBT and SiC inverters in experiments. After that, by designing a common-mode filter, the bearing voltage and current are significantly attenuated. Furthermore, the active zero state PWM (AZSPWM) is adopted to reduce the common-mode voltage from the inverter. At the same time, combined with the common-mode filter, the bearing voltage and current are further reduced. The experimental results show that the switching frequency has a decisive effect on the amplitude of bearing voltage and current. The bearing voltage can be attenuated to around half of the reference bearing voltage by using the common-mode filter and AZSPWM strategy, respectively. The combination of the common-mode filter and AZSPWM strategy can reduce the bearing voltage to around one-fourth of the reference bearing voltage, which can effectively reduce the breakdown time and discharge energy of the grease oil film. [ABSTRACT FROM AUTHOR]

Introduction. Transformerless inverters are of vital importance in the field of grid connected solar photovoltaic systems offering higher efficiency than the conventional one. i.e., using transformer. General grid connected inverters are constituting of transformers requires more area besides the loss in them. Problem. Eliminating transformers can cause leakage current due to the variation of common mode voltage which in turn due to parasitic capacitance effect. Research literature in transformerless inverters has addressed the problems of common mode leakage current issues by offering the study of different inverter topologies like H4, H5, H6 and HERIC etc. utilizing variety of modulation strategies like unipolar, bipolar pulse width modulations. Goal. The paper significantly presents a new transformerless inverter topology, analyzes common mode voltage and leakage current behavior of the system. The simulation is carried out for comparing the leakage current profiles with other transformerless inverter topologies in literature. Novelty. This paper gives an impression of the efficient transformerless inverter for grid connected photovoltaic system. Results. The various inverter topologies full bridge with different pulse width modulation techniques are analyzed and to determine the common mode voltages and leakage currents. [ABSTRACT FROM AUTHOR]

This proposed work deals with the implementation of a single-phase topology with using hybrid for multilevel inverters. It is observed that the proposed structure improves the performance of the hybrid multilevel inverter with high-frequency switches for positive levels and reverse voltage with negative levels. This paper studies a novel construction for an asymmetrical hybrid single-phase multilevel inverter. This paper also studies the operation of multi level inverter under depreciating sources condition due to fluctuation in input. The PWM method, i.e. APOD and CO, has been incorporated into the simulation of single-phase 7-level, 9-level, and the 11-level hybrid inverter. These two methods are compared to one another and to standard methods in terms of THD for different values of the modulation index, and they are found to be superior. Overall loss of 50% of the THD is almost equal to rated output voltage, it is observed in cascaded multilevel inverters. The working and performance of the proposed model are simulated in MATLAB Simulink software and the results are discussed in detail. [ABSTRACT FROM AUTHOR]

This paper presents a novel methodology for the design of the Space Vector (SV) switching sequences in order to reduce the output voltage distortion and the common‐mode voltage (CMV) without increasing the number of commutations in comparison to conventional and optimised techniques presented in the literature. Three spaces can be distinguished in a converter, referring to: line‐to‐line voltages, phase voltages and switching states. Consequently, three correspondent sequences of vectors in each space can be verified. The output voltage distortion, CMV and switching count are mainly affected, respectively, by the sequences in the line‐to‐line voltage, phase voltage and switching state spaces. However, the three spaces are interdependent, and the selection of a sequence in one space affects the ones in the other spaces. As a consequence, this paper presents a novel SV approach, where the line‐to‐line voltage sequences are selected over a fundamental period horizon considering the impact in the phase voltages through an algebraic analysis, assuring minimal phase voltage transitions while using VIKOR method to choose the best trade‐off between reduction of output voltage distortion and CMV. In order to validate the proposed strategy, experimental results are given to a three‐phase five‐level Packed U‐Cell (PUC5) converter. [ABSTRACT FROM AUTHOR]

This paper introduces a new high-step-up, non-isolated switched-inductor switched-capacitor DC-DC converter. The proposed converter remarkably integrates switched-capacitor and switched-inductor cells, leading to a significant increase in voltage gain. This unique composite structure not only ensures the continuity of input current, but also successfully minimizes the current ripple and voltage stress across the components, thereby optimizing efficiency. The standout feature of this converter is its singular switch controlled by pulse-width modulation (PWM), which simplifies its operation. A rigorous steady-state operation analysis is conducted, providing a comprehensive understanding of the converter's performance. For validating the theoretical findings, the paper also details a real-world prototype of the converter. Comparative studies conducted with other similar structures substantiate the superiority of the proposed converter. [ABSTRACT FROM AUTHOR]

Under the current trend of power electronics in energy systems, a high percentage of renewable energy transports clean energy to the grid through grid-connected inverters. The pulse-width modulation (PWM) technique brings high-order harmonics near to the switching frequency, and LCL filters with low-pass characteristics become the common choice for grid-connected inverters. However, the low-order harmonics caused by nonideal switching characteristics are difficult to filter out, and the new resonance point introduced by the LCL filter causes a security problem for the energy systems. Firstly, the generation mechanism of the 6 k ± 1 order harmonic and high-frequency resonance from a PV grid-connected inverter is analyzed. Then, a virtual resistor is constructed by the active damping method to absorb the resonant component. Meanwhile, this paper also presents an adaptive modulation voltage compensation method to decrease the low-order harmonics. Finally, the actual measured data of user photovoltaic (PV) and multiple comparative simulations verify these theories. Simulation results show that the proposed coordinated control algorithm reduces the peak of the resonance point, and the rate of low-order harmonics mitigation is more than 50%. The proposed method is suitable for various operating conditions. [ABSTRACT FROM AUTHOR]

This paper introduces a chip-level oven-controlled system for improving the temperature stability of MEMS resonators wherein we designed the resonator and the micro-hotplate using MEMS technology, then bounding them in a package shell at the chip level. The resonator is transduced by AlN film, and its temperature is monitored by temperature-sensing resistors on both sides. The designed micro-hotplate is placed at the bottom of the resonator chip as a heater and insulated by airgel. The PID pulse width modulation (PWM) circuit controls the heater according to the temperature detection result to provide a constant temperature for the resonator. The proposed oven-controlled MEMS resonator (OCMR) exhibits a frequency drift of 3.5 ppm. Compared with the previously reported similar methods, first, the OCMR structure using airgel combined with a micro-hotplate is proposed for the first time, and the working temperature is extended from 85 °C to 125 °C. Second, our work does not require redesign or additional constraints on the MEMS resonator, so the proposed structure is more general and can be practically applied to other MEMS devices that require temperature control. [ABSTRACT FROM AUTHOR]

The switching frequency of high-power inverters, such as those used in rail transit traction systems, is low, due to switching loss and heat dissipation limitations. This can result in considerable output voltage harmonics. This paper proposes an optimal SPWM strategy for traction inverters based on non-equally spaced carriers to address this issue. By dividing the fundamental wave cycle into regions according to the principle of three-phase, half-wave, and quarter-wave symmetry, the carrier width is symmetrically changed in each region, and a switching angle sequence is generated by comparing the fundamental wave with the non-isometric carrier. The proposed optimal modulation strategy has lower harmonic content than traditional strategies within a specific modulation range. Enhancing the inverter output waveform leads to increased torque accuracy, lowering additional losses in the motor and avoiding overheating. This results in improved performance, enhanced efficiency, and extended service life of the motor system. To further reduce voltage harmonics across the full-speed range, a multi-mode segmented synchronous modulation strategy is designed based on the optimal modulation strategy for different modulation ranges. Appropriate switching points are selected to improve the stability of the traction drive system across the full-speed range. The effectiveness of the proposed method is verified through simulation and experimental results. [ABSTRACT FROM AUTHOR]

The number of applicable carrier-based pulsewidth modulation (PWM) patterns increases with the growth of output levels in scalable multilevel topologies, such as active-neutral-point-clamped (ANPC) converters. Therefore, it is hard to optimize PWM for such topology, especially with large output levels. In this paper, a simplified and modular carrier-based PWM design approach for multilevel ANPC converters is proposed. Inspired by the decomposition theory, the topology decomposition is introduced in this paper to decompose an N-level ANPC converter into low-level subtopologies. Then, the complete set of applicable PWM patterns is derived based on ANPC operation principles, which makes it possible to optimize the performance based on the various requirements in applications. Meanwhile, the carrier-based PWM is implemented through the utilization of subtopologies with low-level modulation schemes, such that the design process of carrier-based PWM is greatly simplified and modularly realized. Both the complete PWM patterns and PWM design examples with experimental results of several ANPC converters are provided to show the feasibility and modularity of the proposed method. [ABSTRACT FROM AUTHOR]

Connection of an LC filter to the output of voltage source inverter (VSI) in squirrel cage induction motor (SQIM) drive converts the pulse-width modulated (PWM) voltages into smooth sinusoidal voltages. However, this connection may lead to closed-loop instability in the rotor flux-oriented (RFO) vector-controlled (VC) SQIM system. The closed-loop stability of the combined SQIM + LC filter (SQLC) system is complex and has not been analyzed properly in the literature. In this paper, a detailed closed-loop stability analysis of the SQLC system has been presented based on stability region (SR) and accordingly the PI gains of VC has been designed. The SR method is adopted to derive the common stability regions for the SQIM system and SQLC system. Thereby, the paper proves that connecting an LC filter in-between the VSI and the SQIM system does not always destabilize the closed-loop system. Further, for an SQLC system, the complete range of current controller gains is obtained at various operating points. The frequency-domain specifications have been used to select a proper stabilizing set and the effect of parametric variation of LC filter on the stabilizing set has also been discussed. The experimental results are provided to validate the analysis. [ABSTRACT FROM AUTHOR]

In industrial electronic equipment or communication equipment, a reference clock should be generated for stable operation of the equipment, which requires precise and stable reference frequency generation. As a method for generating this reference frequency, an analog method called PLL (phase locked-loop) has been devised and widely used. However, in order to make a more precise and stable reference frequency simple and economical, a DDS (direct digital synthesizer) has been developed. In this paper, we propose a stable and accurate method to generate a low frequency of the PWM method via pure logic circuit configuration without a microprocessor for digital reference frequency generation. Depending on the electronic communication equipment, the required reference frequency varies from a low frequency to a very high frequency. The reference frequency synthesis required in these frequency bands has been studied in various ways, but in industries such as railways, the low-frequency band based on the DDS method is used. In particular, it is very important to operate without a single operating error or failure in order to obtain information for stopping the train. Therefore, it is necessary to design a pure logic method that excludes a stored program type processor that minimizes the possibility of temporary interruption due to disturbance such as surge or high voltage. Therefore, through this study, the algorithm is implemented so that the duty ratio is output at 50:50, the circuit is configured so that two target frequencies are generated at the same time, and the performance is verified by generating the low-frequency band used for stopping the railway train. It was confirmed that the accuracy and stability were improved compared to the analog method used for stopping the railway train, and it was verified that the frequency resolution was superior to the similar results obtained in the digital frequency synthesis field so far. [ABSTRACT FROM AUTHOR]

With the increasing penetration of microgrids in distribution systems, the possibility for voltage variations increases. This paper proposes the use of a static synchronous compensator (STATCOM) fed by a DC microgrid to control the voltage of a 3-phase AC distribution grid and provide bidirectional active power transfer from the AC grid to the DC microgrid and vice versa. A simplified control is applied to this system to manage the magnitude and angle of the system voltage at the point of common coupling. With the use of a PI controller and pulse width modulation, the proposed control was able to modify the active and reactive power compensation. The control approach is characterized by its simplicity and rapid response to system changes, such as fault occurrences or load variations. The proposed control system is applied after converting the 3-phase system into a dq system to simplify the voltage regulation process. The PSCAD package is used to perform the simulation. Results demonstrate that it is possible to control STATCOM to offset reactive power and regulate grid voltage. The results validated the ability of active power transfer through the line by injecting negative and positive active power. The transfer of active and reactive power from the AC grid to the DC microgrid, and vice versa, is examined in this study following the STATCOM rating and the energy management demands. [ABSTRACT FROM AUTHOR]

This study proposes a non‐isolated DC converter, which is connected in series with an inverter, with a high output voltage conversion ratio for application in electricity generation systems to upgrade low‐voltage to high‐voltage DC. The topology of the proposed converter is based on a boost converter, which has the limitation of a low voltage conversion ratio. The converter is developed and connected using a coupling inductance technique by adding a second winding L2 coupled with the prototype winding and diode D2. This technique increases the voltage ratio via the ratio operator (N) of both the induction coils by operating a single switch at a constant frequency of 60 kHz. The working principle of the proposed converter is based on pulse width modulation with a duty cycle ≤40%. When the converter receives a low voltage DC input of 36 V, it converts the input to a high output voltage of 325 V at an output power 125 W, showing a circuit efficiency of 92.48% at full load. The synthesis and design of the controller include a linear approach to represent the parameters using the small signal methodology, which is employed to establish a transfer function. Furthermore, the proposed converter is capable of effectively regulating the output voltage, even when subjected to variations in the output load by employing a proportional–integral control mechanism. The close loop results obtained from simulations and practical implementation verified the proposed circuit design, as both results agreed with the theoretical analysis. This paper presented the high output voltage conversion ratio non‐isolated DC converter, which would be applied in the electricity generation system from the substitute source, to upgrade the low‐voltage to the high‐voltage DC, then series connected with DC–AC inverter. The presented converter had the topology development from DC boost converter with the limitation of the low‐voltage conversion ratio, which was developed and corrected with the coupling inductance technique by adding the second winding L2 to coupling with the prototype winding and diode D2. This technique could increase the higher voltage ratio via the ratio operate (N) of both induction coils, with the operating of a single switch, at the constant frequency 60 kHz. It worked according to the pulse width modulation with the duty cycle ≤40%. This converter receives low voltage input 36 VDC provide to high voltage output 325 VDC, at the output power 125 W and the circuit efficiency equal to 92.48%, at the full load. And could maintain the output voltage by PI control under changing of output loading condition. According, it were found that the obtained close loop results from simulation and implementation results verified the proposed and design circuit. Both results agreed with the theoretical analysis. [ABSTRACT FROM AUTHOR]

In some applications of microgrids and distributed generation, it is necessary to feed islanded or stand-alone loads with high-quality voltage to provide low total harmonic distortion (THD). To fulfil these demands, an L C filter is usuallyconnected to the output terminals of power electronics converters. A cascaded voltage and current control loop with pulse-width modulation schemes are used to regulate the voltages and currents in these systems. However, these strategies have some drawbacks, particularly when multiple-input–multiple-output plants (MIMO) are controlled using single-input–single-output (SISO) design methods. This methodology usually produces a sluggish transient response and cross–coupling between different control loops and state variables. In this paper, a model predictive control (MPC) strategy based on the concept of optimal switching sequences (OSS) is designed to control voltage and current in an L C filter connected to a three-level neutral-point clamped converter. The strategy solves an optimisation problem to achieve control of the L C filter variables, i.e., currents and output voltages. Hardware-in-the-loop (HIL) results are obtained to validate the feasibility of the proposed strategy, using a PLECS–RT HIL platform and a dSPACE Microlab Box controller. In addition to the good dynamic performance of the proposed OSS–MPC, it is demonstrated using HIL results that the control algorithm is capable of obtaining low total harmonic distortion (THD) in the output voltage for different operating conditions. [ABSTRACT FROM AUTHOR]

This paper presents a DC-DC converter with wide-range negative output for active-matrix organic light-emitting diode (AMOLED). The generated negative voltage V o u t is connected to the negative terminal of the organic light-emitting diode (OLED), and the luminous brightness is adjusted by changing the value of V o u t . The negative output voltage of the DC-DC converter is regulated by a Buck–Boost topology structure with a dual-loop control (DLC) system composed of a voltage loop and a current loop. The proposed compensatory peak-current-sensing technique (PCST) and switch MOSFETs adaptive drive technique (ADT) successfully support the implementation of the converter topology and enable the converter to work in continuous conduction mode (CCM). In addition, with the DLC system, the converter can guarantee a negative output voltage that enables both a fast transient response such as excellent load/line regulation, and a small output voltage ripple of the pulse width modulation (PWM) control. The proposed chip is implemented in a 0.18   μ m CMOS process that operates at an operating frequency of 2   M H z with a maximum efficiency of 85.82 % . The output voltage ripple is 1.5   m V at typical loading of V o u t = − 4   V and I o u t = 100   m A . [ABSTRACT FROM AUTHOR]

Nowadays, multilevel inverter (MLI)-based induction heating (IH) technology is the best-suited option in many domestic, commercial and medicinal applications because of its higher efficiency, low cost, fast heating and lower electromagnetic interference (EMI). This paper presents reduced components count high-frequency (HF) single phase five-level (5-L) MLI for IH applications. The working methodology of the proposed system has been analyzed in the multicarrier phase disposition pulse width modulation (MC-PD-PWM) method in high switching frequency i.e., 10 kHz. In addition, the proposed topology can produce output voltage twice of input voltage without any external source. Moreover, the detailed power loss and reliability analysis have been evaluated for the proposed system. In terms of switch count and efficiency, the single-phase 5-L inverter architecture is compared to some conventional and current topologies. Finally, to validate and justify the operation of the proposed system, the simulation and experimental results of five-level inverter are presented. [ABSTRACT FROM AUTHOR]

This paper presents the development of a portable solar panel wireless charging device with an advanced charging algorithm. The device features a 6500 mAh Li-ion battery and is designed to efficiently charge smartphones and laptops. It incorporates a simulated solar panel, charging circuit, microcontroller, and wireless charging circuits. Rigorous testing has demonstrated its stable output voltage and current at 5 V/2 A, with high power transfer efficiency. The advanced charging algorithm optimizes power transfer efficiency and reduces charging time by adjusting the current and voltage to match the device's needs. This smart approach extends battery life and improves device performance. The device utilizes the Basic MPPT P&O Algorithm to dynamically track the solar panel's Maximum Power Point and optimize power extraction. The Lithium Battery Charging Characteristic Algorithm adjusts the charging levels to ensure safe and efficient charging. However, challenges were encountered during implementation and testing, highlighting the complexities of real-world scenarios and the need for further optimization. The device offers a sustainable and environmentally friendly charging alternative, particularly in areas with limited power access. The research findings contribute to the field of wireless charging, driving advancements in sustainable and efficient technologies. [ABSTRACT FROM AUTHOR]

For the existing outphasing architectures of an all-digital transmitter (ADTx), the required sampling rate of the signal is too high, which increases the difficulty of digital radio frequency pulse width modulation (RF-PWM) processing. In this paper, we present an outphasing architecture based on the parallel RF-PWM method for an ADTx. Through polyphase interpolation, two baseband outphasing signals are divided into multiple low-rate signals to process simultaneously. The parallel outphasing signals are modulated and encoded to obtain 1-bit parallel signals, which are, respectively, transmitted to multigigabit transceivers (MGTs) to generate two two-level high-speed pulses with different phases. Finally, a three-level high-speed pulse is synthesized and amplified through the switching power amplifier. Through this parallel scheme, the sampling rate of digital RF-PWM signal processing is effectively reduced. Moreover, to explore a pulse encoding method, the outphasing architecture is combined with a zero-crossing comparison through an angle calculation and quadrant judgment, which simplifies the modulation and encoding process. In addition, the impact of the sub-filter order and the number of parallel paths on system performance is analyzed. The simulation results show that for a 16QAM signal with a baseband bandwidth of 20 MHz and a carrier frequency of 200 MHz, the adjacent channel power ratio (ACPR) is below −45 dBc and the error vector magnitude (EVM) is below 1% in the proposed scheme. [ABSTRACT FROM AUTHOR]

To ensure that a variable-rate spray (VRS) system can perform unmanned aerial spray in accordance with a prescription map at different flight speeds, we examine in this paper such significant factors as the response time of the VRS system and the pressure fluctuation of the nozzle during the variable-rate spraying process. The VRS system uses a lag compensation algorithm (LCA) to counteract the droplet deposition position lag caused by the system response delay. In addition, pulse width modulated solenoid valves are used for controlling the flowrates of the nozzles on the variablerate spray system, and a mathematical model was constructed for the spray rate (L min-1) and the relative proportion of time (duty cycle) each solenoid valve is open. The pressure drop and solenoid valve response time at different duty cycles (50~90%) were measured by indoor experiments. Meanwhile, the lag distance (LD), spray accuracy, and droplet deposition characteristics of the VRS system were tested by conducting outdoor experiments at different flight speeds (4m s-1, 5m s-1, 6m s-1). The results show that LCA can effectively reduce the LD. The LD values of the VRS system with LCA ranged from -0.27 to 0.78m with an average value of 0.32m, while without LCA, the LD values increased to 3.5~4.3m with an average value of 3.87m. The overall spray position accuracy was in the range of 91.56~97.32%. Furthermore, the spray coverage and deposition density, determined using water sensitive paper, were used to evaluate the spray application performance taking into account the spray volume applied. The VRS system can provide the most suitable spray volumes for insecticide and fungicide plant protection products. Based on a prescription map, the optimized VRS system can achieve accurate pesticide spraying as well as desirable spray coverage and deposition density. [ABSTRACT FROM AUTHOR]

In order to effectively mitigate the issue of frequent fluctuations in the output power of a PV system, this paper proposes a working mode for PV and energy storage battery integration. To address maximum power point tracking of PV cells, a fuzzy control-based tracking strategy is adopted. The principles and corresponding mathematical models are analyzed for the three-phase voltage PWM converter and bidirectional DC/DC converter, while feedforward decoupling double closed loop, constant power (PQ), and constant voltage charge/discharge control strategies are proposed. Space vector pulse width modulation (SVPWM) technology is utilized to generate power switching tube driver signals. Finally, a simulation model is developed in MATLAB/Simulink for system analysis. The results demonstrate that the proposed method enables constant grid-connected power generation and constant voltage charging of the energy storage battery when the PV cell's power generation exceeds that of the grid. When insufficient solar power generation occurs, both the PV system and energy storage battery work together to achieve constant grid-connected power. [ABSTRACT FROM AUTHOR]

Due to its advantages, the asymmetrical dual three-phase induction motor drive is a strong choice in high-power applications. However, the common-mode voltage produced by the voltage source inverters affects the winding insulation and damages the bearings. Common-mode voltage is also responsible for electromagnetic interference and leakage currents. This paper, therefore, analyses the common-mode voltage produced by the inverter supplying a dual three-phase induction motor drive and proposes a novel modified space vector decomposition-based Space Vector Pulse Width Modulation (SVPWM) technique for common mode reduction. The vector space decomposition-based space vector modulation technique offers excellent flexibility as it reduces the common-mode voltage (CMV) by exploiting the additional degree of freedom in a dual three-phase system. The common-mode voltage (CMV) can be reduced to one-sixth of the DC link voltage compared to the highest CMV, i.e. half of the DC-link voltage produced in conventional space vector modulation. The proposed method is also validated experimentally to demonstrate the effectiveness of the proposed scheme in terms of the amplitude of CMV, pulsations, and total harmonic distortion(THD) in current. [ABSTRACT FROM AUTHOR]

In order to effectively avoid the shoot-through issue of the semiconductor device (such as the power metal-oxide-semiconductor field-effect transistor (MOSFET)) adopted in the phase leg of the motor drives, a dead-time zone should be inserted. However, the nonlinearity caused by the dead-time effect will bring about voltage/current distortion, as well as high-order harmonics, which largely degrades the performance of motor drives, especially in low-speed operations with slight loads. In this paper, a dead-time compensation method is proposed to suppress such side effects caused by dead-time zones and improve the performance of motor drives. Compared with other existing methods, the proposed method is mainly focused on the switching characteristics of the power MOSFET, which is directly relative to the compensation time in each pulse-width modulation (PWM) period. Firstly, a detailed derivation process is elaborated to reveal the relationship between compensation time and the switching performance of the MOSFET. Meanwhile, the switching process of the MOSFET is also well analyzed, which summarizes the variations in the switching time of the MOSFET with a varied load current. Then, the multipulse test (MPT) is carried out to obtain accurate values of the switching time with the varied load current in a wide range (0–80 A) and form a 2D lookup table. As a result, the compensation method can easily be realized by combining the lookup table and linear interpolation based on the phase current of the motor dynamically. Finally, the effectiveness of the proposed method is verified based on a 12 V permanent magnet synchronous machine (PMSM) drive system. According to the relative experiment results, it can be clearly observed that the time-domain waveform distortion, high-order harmonics, and total harmonic distortion (THD) value are reduced significantly with the proposed dynamic compensation method. [ABSTRACT FROM AUTHOR]

Three-level NPC inverters have been widely used in grid-connected systems due to their superior performance compared with two-level inverters, but more switches lead to high fault probability. Meanwhile, the neutral point potential (NPP) fluctuation of the DC link is an inherent problem of three-level NPC inverters. To keep the three-level NPC inverter running stably after single-arm failure, a fault-tolerant control strategy based on an optimised space vector pulse width modulation (SVPWM) is proposed in this paper. Firstly, the common-mode voltage (CMV) of the postfault three-level NPC inverter is analysed and then the preliminary synthesis principles of the reference voltage vector are determined. Then, in order to ensure the NPP balance and the quality of the grid-connected currents, the reference voltage vector synthesis rules are optimised, a low-pass filter (LPF) and a hysteresis comparator are designed, respectively, to ensure the quality of grid-connected currents and effectively decrease the DC link NPP deviation. Finally, the simulation results show that the proposed fault-tolerant control strategy can realize the stable and reliable operation of the grid-connected three-level NPC inverter after single-arm failure, and the CMV can be reduced significantly, the quality of grid-connected currents is also improved. The proposed fault-tolerant strategy also shows good performance when the grid-connected currents change. [ABSTRACT FROM AUTHOR]

As a power converter of battery energy storage, the multi-level converter and its battery balancing control have received much attention from scholars. This paper focuses on the modular multi-level half-bridge energy storage converter (MMH-ESC), including its topology, working principle, and pulse width modulation (PWM) methods. Under the battery balancing control strategy based on level-shifted carrier PWM (LS-PWM), formulas are derived and calculations are performed to get the charge or discharge of each submodule (SM), thereby obtaining the tolerance for capacity differences among these batteries. A range of battery capacity values that can maintain a balanced state is provided to enhance flexibility in battery configuration and utilization, avoiding the limitation of all batteries to the same capacity. Finally, a new bridge arm modulation wave allocation method is proposed. This method significantly expands the range of SM battery capacity selection and provides a high-tolerance modulation method for the converter under extreme or even fault conditions. [ABSTRACT FROM AUTHOR]

In modern controller design, various solutions for controlling power converter systems can be found depending on their applications, speed of working, pulse width modulation (PWM) techniques, switching frequencies— f c , and different load types. The need to manipulate control parameters can be often observed in classical structures, e.g., well-known PID, repetitive, or deadbeat control particularly sensitive to distinct parameters uncertainties. The purpose of this paper is to present an improved version of controllers designated for a UPS that will be considerably resistant to model changes. Proposed control techniques are independent of unexpected output filter changes: L f —filter coil inductance and C f —filter capacitor conductance. The second aspect of this paper is to compare effectiveness of modified predictive MPC (model-predictive control) and feedback PBC (passivity-based control) controllers in reducing output voltage total harmonic distortion (THD) for various load values. The biggest distortions of output voltage were observed during experiments with nonlinear RC load. Both simulation and experimental verification of mismatching parameters were performed and examined. Thanks to the proposed solution, the output voltage T H D v quality factor was reduced below 8% in an efficient way for all the applied loads and stayed at the level of 1% when well-matched filter parameters were provided. [ABSTRACT FROM AUTHOR]

In this paper, in order to improve the control performance of a high-power electrically excited synchronous motor (EESM) under low switching frequency, and to improve the poor dynamic response of the traditional selective harmonic elimination pulse width modulation (SHEPWM) strategy, an optimized pulse width modulation (PWM) pulse mode with specific harmonic elimination and good dynamic performance is studied. Based on the fast response characteristics of predictive control, it combines the rolling time domain optimization theory with SHEPWM strategy. Firstly, the stator flux linkage of EESM is taken as the tracking target, and the real-time tracking error value of flux linkage is transformed into a voltage-second product; then, the predictive rolling time domain is established, the above error voltage-second product value is optimized in this time domain and the switching angle of SHEPWM is dynamically adjusted to minimize the stator tracking error so as to realize the dynamic adjustment of EESM at low switching frequency. Through MATLAB simulation and a 50 kW experimental platform, the optimized modulation strategy proposed in this paper has been verified to have good dynamic regulation performance at low switching frequency (≈500 Hz). [ABSTRACT FROM AUTHOR]

This paper introduces a novel 7‐level active neutral‐point clamped (ANPC) switched capacitor multilevel inverter (SCMLI) with voltage‐boosting capabilities. The proposed converter can produce seven levels and a voltage boosting of 1.5 times with a single dc source. For boosting the voltage, two self‐balanced switched capacitors and two dc link capacitors with active neutral point are used with nine switches. For controlling the output voltage, the level‐shifted modulation technique and modified nearest level control technique is used. The performance of the converter is evaluated with both modulation techniques. The operation of the proposed SCMLI and the design of capacitors for the proposed circuit is discussed in detail. The proposed topology can eliminate the leakage current and has reduced voltage stress across switches which makes it suitable for solar photovoltaic applications. The proposed converter is compared with some other recently introduced converters in terms of voltage gain, the number of components used, and the voltage stress across the switches. For verifying the performance of the proposed circuit, the experimental and simulation results are presented in the paper. The experimental results closely agree with the simulation and theoretical studies. The total harmonic distortion (THD) in the output voltage and efficiency is compared with both modulation techniques. [ABSTRACT FROM AUTHOR]

The four‐level nested neutral point clamped (4L‐NNPC) converter is a new multi‐level converter with a simple topology, which is suitable for the medium‐voltage application. But it has voltage balancing problems under the low output frequency condition. A space virtual vector modulation (SVVM) algorithm is introduced in this paper, and the dwell time formulas are given. It uses the synthesis between vectors to optimize the dwell time of each level in the virtual vector, in order to balance the flying capacitor voltage in the carrier period. In order to explore the boundary of the voltage regulation ability of the 4L‐NNPC converter, this paper analyses the mechanism of the voltage fluctuation of the flying capacitors and derives the voltage fluctuation formulas. The voltage regulation ability is calculated in different sectors, and the influence of the modulation ratio and power factor is explored. Finally, the voltage regulation ability under the sudden load and the flying capacitor voltage deviating from the rated value were investigated through simulation and experiments, which verified the correctness of the proposed theory. [ABSTRACT FROM AUTHOR]

The reliability assessment of electric machines plays a very critical role in today's engineering world. The reliability assessment requires a good understanding of electric motors and their root causes. Electric machines mostly fail due to mechanical problems and bearing damage is the main source of this. The bearings can be damaged by mechanical, electrical, and thermal stresses. Among all stresses, the researcher should give special attention to the electrical one, which is bearing current and shaft voltage. This review paper introduces a comprehensive study of bearing current and shaft voltage for inverter-fed electric machines. This study aims to discuss several motor failure processes, as well as the sources and definitions of bearing current and shaft voltage. The different kinds of bearing currents are addressed and the parasitic capacitances, which are the key component to describe bearing current, are determined. Several measurement approaches of bearing current will be discussed. Furthermore, modeling of bearing current will be covered together with the machine's parasitic capacitances. Moreover, the different bearing current mitigation techniques, as described in many papers, will be thoroughly addressed. The use of rewound multiphase machines for mitigation of bearing current will be proposed and compared to a three-phase machine. Finally, various pulse width modulation techniques of multiphase systems that reduce bearing current and shaft voltage will be investigated, and the findings described in the literature will be summarized for all techniques. [ABSTRACT FROM AUTHOR]

Large‐scale wind farms are susceptible to oscillations like any other power systems with high penetration of power electronics, whose characteristics of wideband impedance hold the key to resolving this issue. However, due to the high cost of impedance measurements for power systems, computational modelling methods are usually used, accuracy of which is difficult to be verified. This paper proposes a novel AC chopper integrated with active measurement of wideband impedance (AIM‐ACC), which can be slightly modified from the existing energy consuming devices in wind power systems. With the help of the proposed Reversed‐phase Chirp Pulse Width Modulation (RC‐PWM) signal, the AIM‐ACC generates chopper current within a desired wide frequency band, avoiding the spectral shifting effects of sinusoidal voltages. Thus, the impedance characteristics of wind system are obtained by measuring the injected current and its corresponding voltage, with fast excitation time, good controllability and high accuracy. Finally, the verification of an experiment with single‐phase branch and a simulation with the proposed AC chopper in wind power system was carried out for the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes an analytical formulation-based minimization of DC link current ripples for interleaved parallel inverter systems. Parallel inverter systems find applications in multiple fields. The interleaved superposition of the DC link currents in these systems can potentially be adjusted to mitigate the overall harmonics consequently reducing the DC link capacitor size. To this end, a widely used approach in the literature is the Fourier analysis based on interleaving focusing on dominant harmonic mitigation. However, it leaves room for a generic analytical mechanism to provide time shifts leading to an optimal reduction in DC-link ripples. The goal of this work is to target this optimal reduction by utilizing an analytical mechanism. The paper presents an alternate way of DC-link formulation in terms of the piece-wise sinusoids of inverter output currents for space vector modulation-based systems. The formulation is then used to numerically optimize the interleaved shifts for minimum ripples. Moreover, in addition to the traditional concept of fixed time interleaving, a contemporary concept of sequence-based interleaving is utilized, which is anticipated to have more flexibility in the implementation and additional switching synchronism with PWM rectifiers for back–back converters. Therefore, the sequence interleaving has also been utilized in conjunction with the proposed ripple reduction methodology. Further, an underexplored area of using the combined impact of sequence and time interleaving has also been applied in this work. These interleaving methods are shown to provide significantly improved DC-link ripple mitigation, as compared to existing methods, using numerical assessment followed by simulations and experimental evaluation. [ABSTRACT FROM AUTHOR]

During the last decade, field oriented control has often been implemented with space vector modulation due to its inherent advantages over other modulation techniques. On the other hand, direct flux control is a method that estimates the rotor electrical position of synchronous machines (e.g., permanent magnet synchronous motors) using only voltage measurements. In simple terms, direct flux control replaces position sensors by measuring the voltage difference between the star point of the synchronous machine and an artificial star point at particular instants during the switching pattern. Indeed, previous work dealt with direct flux control resorting exclusively to sinusoidal pulse width modulation and mostly in open-loop speed control schemes. This paper aims to present a space vector modulation-based direct flux control measurement sequence that can be used directly with field oriented control to perform sensorless speed control of synchronous machines. In contrast with previous publications, the direct flux control measurement sequence proposed in this paper not only extracts the direct flux control flux linkage signals with the same offset level but also obtains the phase currents needed for field oriented control without current ripple. In simple terms, the proposed direct flux control measurement sequence based on space vector modulation can be used with field oriented control to perform sensorless closed-loop speed control of synchronous machines. The sensorless speed control with the space vector modulation-based direct flux control sequence is validated for high speeds (80% of the nominal speed) and low speeds (6% of the nominal speed) using a high-fidelity four-pole synchronous machine's simulation model implemented in ANSYS Simplorer and Maxwell. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of a constant carrier phase shift on the DC-link capacitor harmonic current of cascaded converters used in fuel-cell and mild-hybrid electric vehicles. In these applications, a DC-DC converter can be adopted between the battery and the motor drive inverter in a cascaded structure, where the two converters share the same DC-link. Since the DC-link capacitor of such a system represents a critical component, the optimization of the converter operation to limit the current stress and extend the lifetime of the capacitor is an primary objective. This paper proposes the use of a carrier phase shift between the modulations of the two converters in order to minimize the harmonic current of the DC-link capacitor. By harmonic analysis, an optimal carrier phase shift can be derived depending on the converter configuration. Analytical results are presented and validated by hardware-in-the-loop experiments. The findings show that the pulse width modulation carrier phase shift between the interleaved boost converter and the voltage source motor drive inverter has a significant influence on the DC-link capacitor current and thus on its lifetime. A case study with two-cell and three-cell interleaved boost converters shows a possible DC-link capacitor lifetime extension of up to 390%. [ABSTRACT FROM AUTHOR]

Multiphase variable-speed drives and generation systems (systems with more than three phases) have become one of the mainstream research areas during the last decade. The main driving forces are the specific applications, predominantly related to the green agenda, such as electric and hybrid electric vehicles (EVs), locomotive traction, ship propulsion, “more-electric” aircraft, remote offshore wind farms for electric energy generation, and general high-power industrial applications. As a result, produced body of significant work is substantial, making it impossible to review all the major developments in a single paper. This paper therefore surveys the recent progress in two specific areas associated with multiphase systems, namely power electronic supply control and innovative ways of using the additional degrees of freedom in multiphase machines for various nontraditional purposes. [ABSTRACT FROM AUTHOR]

This paper proposes a single-phase ac–dc–ac converter composed of a transformer and two three-leg converters connected in series. The proposed converter allows to supply the load with a voltage with constant amplitude and frequency, and to operate with the grid current with low harmonic distortion and high power factor. In addition, the converter can be used to mitigate fundamental overvoltage and voltage harmonics at the grid. The system model, regions of operation, a power flow analysis, and a method to regulate the dc-link voltages using the voltage vector redundancies are given. In the first version of this paper, two pulsewidth modulation (PWM) techniques (including space vector PWM) and a control system were provided. The proposed topology is compared with two conventional systems in terms of operation range, harmonic distortions, and semiconductor losses. Simulation and experimental results are provided to validate the feasibility of the system. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LEDs) are widely used in street lighting, landscape lighting, liquid crystal display (LCD) backlighting, healthcare, etc. As an important part of LED lighting products, LED driver plays a vital role in maintenance costs reduction, energy saving and lifetime prolongation. In this paper, a single-stage LED driver is proposed, which is integrated by a totem-pole bridgeless power factor correction (PFC) unit and several modular LCL-T resonant rectifiers. The totem-pole bridgeless PFC unit and the LCL-T resonant rectifiers are integrated by sharing switches, which can simplify the circuit and reduce the system cost. The output current can be regulated by applying the variable inductor control. Constant duty cycle and fixed switching frequency operation can be achieved as well. The operating principle and the performance of the proposed converter are analyzed in this paper. In addition, a precise parameter design method is proposed by considering the high-order harmonics. At last, an experimental prototype is established to validate the proposed parameter design and variable inductor control method. [ABSTRACT FROM AUTHOR]

In this paper, a soft-switched three-phase resonant converter with a low quality factor (Q) design is proposed for Photovoltaic (PV) energy harvesting systems with a very wide range of operating conditions. Due to the low quality factor (Q ≤ 1), the voltage stress across the capacitors is drastically reduced. However, a major challenge of using a low Q design is the wide switching frequency range required for operation over a wide range of load and input conditions. In order to reduce the switching frequency range, this paper introduces a hybrid modulation technique employing asymmetric pulse width modulation (APWM) along with variable frequency modulation. The proposed modulation scheme also substantially extends the soft-switching range of the converter from full-load upto 10–35% load condition over a wide range of line voltages. To sustain soft-switching in the entire operating region of the converter, the converter is operated in a hybrid structure with single-phase and burst modes at light load conditions. A comprehensive time-domain analysis of the proposed converter is presented, which greatly improves accuracy over conventional frequency-domain modeling. Experimental results from a 1 kW prototype are presented to verify the performance of the converter and validate the theoretical analysis. [ABSTRACT FROM AUTHOR]

Nine-leg voltage source inverters (VSIs) are highly effective topologies for high-power industrial applications. In this paper, a novel space vector with pulse-width modulation (SVPWM) approach for a nine-leg VSI fed three-star induction machines (TSIMs) is proposed. In fact, for nine-leg VSI fed TSIM, large stator harmonic currents are observed in the case of a 30° electrical shift between stator stars. The main objective of this paper is to minimize the circulation of these harmonics on (x-y) and (z–w) planes by developing a new SVPWM strategy for the nine-leg VSI. The effectiveness of the proposed strategy in terms of reducing the stator harmonic currents and electromagnetic torque ripple on the topology is, firstly, verified by computer simulations at different levels of the modulation index. The obtained results show that a compromise between the proposed technique and the proper choice of the modulation index provides high performance of the topology. On the other hand, an experimental test on a laboratory prototype of the nine-leg VSI fed TSIM shifted by 30° is carried out using a Virtex 5 LX50T FPGA. The experimental results prove the accuracy of the numerical results and therefore the efficacy of the proposed technique. [ABSTRACT FROM AUTHOR]

This study presents the characteristics and performance of a motor at the operating point based on pulse-width modulation (PWM). PWM is used in modulating the output voltage of a three-phase inverter. The PWM technique has advantages and disadvantages depending on the system size and operating range. For example, some discontinuous pulse-width modulation (DPWM) techniques are advantageous in low-cost systems because they can reduce the number of switches. Some PWM techniques are complicated for software construction and require a lot of computation. In this paper, PWM techniques were constructed by using the offset voltage injection method. Therefore, the construction of the PWM technique is simplified by the method. In an experimental setup, an interior permanent-magnet synchronous motor (IPMSM) and a three-phase inverter were implemented to test motor control performance depending on the PWM technique. In addition, the current control characteristics and inverter efficiency were analyzed and compared depending on the speed and load of the motor. According to the results of this paper, it is possible to compare the motor and inverter control characteristics using various types of PWM rapidly. Additionally, it will help to select an appropriate PWM technique for a specific system. [ABSTRACT FROM AUTHOR]

A modular multilevel converter (MMC) can generate different common-mode voltage (CMV) values due to the high-frequency changing of the switching state under various modulation strategies. The high-frequency dv/dt will produce common-mode current in the equivalent common-mode loop to the ground, which will affect the insulation and shorten the life of the equipment. To eliminate the effect of common-mode voltage on MMC operation, a common-mode voltage elimination strategy (0CMV-SVPWM) is proposed for five-level MMC space vector pulse width modulation (SVPWM) by using the vector that does not generate common-mode voltage as the reference vector in this paper. The proposed strategy is studied and analyzed by the rapid prototype development experimental system based on RT-LAB to verify the feasibility and effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

In this paper, advanced DC-Link (DCL) based reversing voltage type Multilevel Inverter (MLI) topologies by compensating the difficulties in the conventional MLIs are reviewed. These topologies consist of less switching components and driver circuits when compared with conventional MLIs predominantly in higher levels. Consequently, installation area, total cost and hardware difficulties are reduced by increasing the voltage levels. The unipolar based Pulse Width Modulation Schemes (PWMS) will improve DCL inverters performance. This paper presents unipolar Multi-Reference (MR) based sine and space vector PWMS with single triangular carrier wave for generating required levels in output voltage. Comparison between UMR sine and space vector PWMS for DCL inverter topologies is presented in terms of Fundamental Output Voltage (FOV) and Total Harmonic Distortion (THD). The research tries to establish the survey analysis for single-phase 7-level DCL based reversing voltage type MLI topologies with UMR based sine and space vector PWMs. Finally, to confirm the feasibility of proposed DCL-MLIs in terms of FOV and THD the simulation results are incorporated. Further, the prototype model is developed for single-phase 7-level DCL inverter with Field Programmable Gate Array (FPGA) based UMR sine and space vector PWMS to authenticate simulation results. The efficiency of the proposed cascaded MLI achieves the value of 99.003%. [ABSTRACT FROM AUTHOR]

Power converters generate switching common mode voltage (CMV) through the pulse width modulation (PWM). Several problems occur in the drive systems due to the generated CMV. These problems can be dangerous to the insulation and bearings of the electric machine windings. In recent years, many modulation methods have been developed to reduce the CMV in multiphase machines. Symmetrical nine-phase machines with single-neutral are considered in this paper. In this case, conventional PWM uses eight active vectors of different magnitudes in combination with two zero states in a switching cycle, and this generates maximum CMV. This paper proposes two PWM schemes to reduce the CMV in such a system. The first scheme is called active zero state (AZS). It replaces the zero vectors with suitable opposite active vectors. The second scheme uses ten large active vectors during switching and is called SVM-10L. Compared with conventional strategies, the AZS reduces the peak CMV by 22.2%, and the SVM-10L reduces the peak CMV by 88.8%. Moreover, this paper presents a carrier-based implementation of the proposed schemes to simplify the implementation. The proposed schemes are assessed using simulations and experimental studies for an induction motor load under different case studies. [ABSTRACT FROM AUTHOR]