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This work experimentally addresses damage calibration of an unmanned aerial vehicle in operational condition. A wide range of damage level and types are simulated and controlled by an electric motor via pulse width modulation in this regard. The measurement is carried out via established protocols of using a piezo-patch on one of the 8 arms, utilising the vibration sensitivity and flexibility of the arms, demonstrating repeatability of such protocol. Subsequently, recurrence analysis on the voltage time series data is performed for detection of damage. Quantifiers of damage extent are then created for the full range of damage conditions, including the extreme case of complete loss of power. Experimental baseline condition for no damage condition is also established in this regard. Both diagonal-line and vertical-line based indicators from recurrence analysis are sensitive to the quantitative estimates of damage levels and a statistical test of significance analysis confirms that it is possible to automate distinguishing the levels of damage. The damage quantifiers proposed in this paper are useful for rapid monitoring of unmanned aerial vehicle operations of connection. [ABSTRACT FROM AUTHOR]

Cardiac monitoring systems in Internet of Things (IoT) healthcare, reliant on limited battery and computational capacity, need efficient local processing and wireless transmission for comprehensive analysis. Due to the power-intensive wireless transmission in IoT devices, ECG signal compression is essential to minimize data transfer. This paper presents a real-time, low-complexity algorithm for compressing electrocardiogram (ECG) signals. The algorithm uses just nine arithmetic operations per ECG sample point, generating a hybrid Pulse Width Modulation (PWM) signal storable in a compact 4-bit resolution format. Despite its simplicity, it performs comparably to existing methods in terms of Percentage Root-Mean-Square Difference (PRD) and space-saving while significantly reducing complexity and maintaining robustness against signal noise. It achieves an average Bit Compression Ratio (BCR) of 4 and space savings of 90.4% for ECG signals in the MIT-BIH database, with a PRD of 0.33% and a Quality Score (QS) of 12. The reconstructed signal shows no adverse effects on QRS complex detection and heart rate variability, preserving both the signal amplitude and periodicity. This efficient method for transferring ECG data from wearable devices enables real-time cardiac activity monitoring with reduced data storage requirements. Its versatility suggests potential broader applications, extending to compression of various signal types beyond ECG. [ABSTRACT FROM AUTHOR]

In PMSM drive systems, sensor-less vector control of permanent magnet synchronous motors (PMSM) over the entire speed range poses considerable challenges. Through the design and simulation of the sensor-less vector control system of PMSM, this paper proposes a novel method for sensor-less field-oriented control (FOC) for PMSM applications. To solve this intricate control problem, FOC combines gh-reference frame space vector pulse width modulation (SVPWM) with cubature Kalman filter (CKF). Implementing CKF to estimate rotor position and speed accurately provides the basis for this sensor-less control technique. Furthermore, the integrated control system using gh-SVPWM aims to reduce controller board computing resources utilization while minimizing torque ripple and stator current harmonic distortion. The effectiveness of CKF-based sensor-less FOC integrated with gh-SVPWM is verified in various operating environments using an extensive simulation and experimental framework, confirming its potential to enhance PMSM driving performance and efficiency in different applications. [ABSTRACT FROM AUTHOR]

Practical testing of distance relays under power swing conditions is becoming all the more essential. This is in view of the increasing use of power electronic apparatus due to penetration of renewable sources and/or FACTS controllers now-a-days. To perform such practical tests, a hardware platform emulating power system swing occurrences, as caused by electromechanical oscillation of alternators, is necessary. As a first step it is required to model the phenomenon before its implementation. In this paper an analytical small-signal model of the low-frequency electromechanical oscillations in a grid-connected alternator is presented. Off-line simulation-based validation for a Single Machine Infinite Bus (SMIB) system is done. To emulate an open-loop alternator, a prototype of a controlled grid synchronised VSI with AC-side reactor is developed and practically tested. A control scheme is proposed and implemented to emulate the active power swing phenomenon. Effects of machine inertia and initial power angle on the swing characteristics are investigated. In-process estimation of apparent impedances, as seen from the distance relay terminals downstream towards the grid, is done. Principle of estimating the apparent impedance during power swing is presented with corresponding experimental results. Both real-time and off-line simulation results are in close agreement with the experimental results thus establishing the accuracy of the model and the precision of the experiments. [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]

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 this paper, Fast space vector pulse width modulation (SVPWM) and a switching structure based on sliding mode control (SMC) and active disturbance rejection control (ADRC) are proposed to improve the dynamic performance and restrain the disturbance of the offshore permanent magnet synchronous generator (PMSG) wind power system. According to the known or unknown system states and the types of disturbance, the control systems switch to the different controller to overcome the unknown states and disturbances effects. Compared to the traditional SVPWM algorithm, the fast SVPWM algorithm has more strong function of pulse modulation and harmonic wave restraints, and shortens the data processing time. The simulation results show that the SMC and ADRC control based on the switching structure restrain the different types of disturbances in complicated offshore environment, and improve the response speed and energy conversion rate of the PMSG wind power system. [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]

In this paper, a single-phase direct pulse width modulation (PWM) buck-boost AC–AC converter is proposed. The proposed converter utilizes a minimum number of semiconductor switches and passive components that decreases the converter power losses and offers high efficiency. It can be operated with simple PWM control and doesn't require soft-commutation strategies. It does not suffer from input source shoot-through and commutation problems. Moreover, it supplies both continuous input and output currents. The common sharing ground of the input and output gives the proposed converter the feature that it can be utilized for voltage sag and swell compensation. A comparison of the proposed converter performance with similar existing converters is presented. Also, detailed circuit analysis, component design guidelines, and simulation results using the MATLAB/Simulink environment are demonstrated. A laboratory prototype has been built and tested to validate the converter performance and confirm the results obtained by computer simulation. [ABSTRACT FROM AUTHOR]

The most prevalent reason for IGBT failure in voltage-source inverter (VSI) is thermal stress, which is influenced by the topology and modulation technique adopted. Hence, it is crucial to understand the impact of common sinusoidal pulse width modulation (PWM) strategies on the thermal behavior of VSI and develop improved PWM techniques. This paper presents an alternate hybrid PWM (AHPWM) switching sequence for a single-phase VSI to decrease its thermal stress and prolong its lifetime. To evaluate the number of cycles to failure of VSI, power loss and thermal analysis were conducted for VSI with AHPWM and compared with conventional PWMs. The thermal cycles experienced by IGBTs with different modulation techniques were experimentally validated using a laboratory prototype of VSI. These findings suggest that by employing AHPWM, the likelihood of VSI failure is reduced by at least one-and-a-half times, resulting in lower VSI maintenance costs. [ABSTRACT FROM AUTHOR]

The modulation of a voltage source inverter output causes losses and harmonic distortions on the load side and the DC-link capacitor due to the discrete switching of the semiconductors. High-frequent voltage pulses are digitally programmed to control the inverter output and determine the harmonic distortions. This paper presents an optimization in terms of pulse- and frequency-pattern selection for reducing load distortions while keeping DC-link losses minimal. In detail, the fact that pulse and frequency patterns are independent from each other is utilized and a modified three-zone hybrid space vector pulse-width modulation is proposed where optimal frequency patterns are selected for every carrier cycle. Simulations and experimental results validate the optimizations. [ABSTRACT FROM AUTHOR]

This paper proposes a multilevel DC-link inverter (MLDCLI) with level doubling source (LDS) for photovoltaic application. The MLDCLI-LDS works for both symmetric and asymmetric configurations. In a symmetric configuration, the required number of controlled switches and DC sources is [N + 5] and [(N − 1)/2], respectively; in an asymmetric configuration, the required number of controlled switches and DC sources is [6 + (2log2(N + 3)/3)] and [log2(N + 3)/3], respectively. Here, N is the number of output voltage levels. The MLDCLI-LDS is compared with the existing topologies in terms of number of controlled switches, uncontrolled switches (diodes), DC sources, and capacitors. The proposed MLDCLI-LDS uses minimal number of switches, DC sources, and capacitors. The proposed topology is validated in MATLAB/SIMULINK using the phase disposition level shift pulse width modulation approach with a carrier frequency of 50 Hz. A prototype model is developed in the laboratory using dSPACE 1104 to validate the proposed topology experimentally. Total harmonic distortion of the output voltage waveform is recorded (9.05%, 3.7%, and 2.5% for 9-level, 21-level, and 45-level, respectively). [ABSTRACT FROM AUTHOR]

The effective insulation design of the stress grading (SG) system in form-wound stator coils is essential for preventing partial discharges and excessive heat generation under pulse-width modulation excitation. This paper proposes a method to find the optimal insulation design of the SG system aimed at reducing the dielectric and thermal stresses in the machine coil. The non-uniform transmission line model is used to predict the voltage propagation along the overhang, SG, and slot regions considering the variation in the physical properties of the insulation layers. The machine coil parameters for different insulation materials are calculated by using the finite element method. Two optimization algorithms, fmincon and particle swarm optimization (PSO), are applied and compared to find the optimal thickness and material properties of each insulation layer as well as the length and location of the SG system. The results under different rise-time excitation show that the optimized geometry by using PSO can produce a higher reduction in the dielectric and thermal stresses, as well as in the maximum overvoltage along the machine coil than the original geometry and the optimized geometry using fmincon. The machine coil model is validated by means of comparisons with experimental measurements. [ABSTRACT FROM AUTHOR]

A novel pulse width modulation (PWM) overmodulation technique based on splitting variable modulating waveform is proposed in this paper. It aims to solve the disadvantages of complex and difficult application of the existing space vector pulse width modulation (SVPWM) overmodulation algorithm and offer a simpler implementation for overmodulation than classic SVPWM techniques. When the modulation index M is within the linear modulation range [0, 1], the modulating waveform is a sinusoidal wave. With the M is increasing within [1, 4/π], the modulating waveform area expands continuously until it becomes a square wave. The PWM output voltage of the vector control system is implemented by using triangle carrier-based sampling pulse width modulation. Furthermore, digital low-pass filters are used in the d-axis current and q-axis voltage of the system, in order to eliminate the negative influence of the PWM low-order harmonics on the proportion integration control in the overmodulation range. The control software is modified and improved to overcome the shortage of slow response speed. The basic logic of the software is to close the filtering process once the load or speed instructions changes and turn on the filtering process when the transient process ends. The contradiction between the filtering and dynamic responses is thus eliminated by using the basic logic. Compared with the SVPWM working in linear region, the constant torque speed regulating range of the AC motor has an improvement of 10% based on the proposed technique. Simulated and experimental results indicate the good effectiveness and feasibility of this technique. [ABSTRACT FROM AUTHOR]

This paper introduces a novel technique to maintain the operation of the five-phase permanent magnet synchronous motor post the failure in two phases of the motor and post the failure of the speed sensor occurs simultaneously. To achieve that, firstly, a fault-tolerant control (FTC) technique is implemented. The FTC is based on implementing two new space vector pulse width modulation (SVPWM) besides using field-oriented control to minimize the torque ripple and to maintain the performance post the two-phase failure. Secondly, algorithms are proposed to obtain the saliency position post the failure of the two phases. The technique is based on measuring the transient response of the motor's remaining healthy currents due to the inverter switching actions. These switching actions are related to the PWM signals obtained from the new SVPWM techniques implemented post the two-phase failure. The whole control technique post the failures is very simple to implement. Simulation results are provided to verify the reliability of the proposed control technique to maintain the performance of the five-phase motor drive post the failure in the two phases and the failure of the speed sensor occurred simultaneously without compromising the preperformance (maintain the torque ripple less than 3.6% and 3.4% post the failure). Moreover, the results have demonstrated the ability for the whole system to work effectively over a wide speed range and load conditions post the failure. [ABSTRACT FROM AUTHOR]

A multi-level inverter (MLI) is essential to improve the performance and efficiency of the inverter, which is widely accepted for high-power and high-voltage applications. Its performance is significantly superior due to higher DC link voltages, lower electromagnetic interference, and lower harmonic distortion. However, it has some drawbacks, like voltage balancing problems, complex pulse width modulation methods, and an increased number of components. This paper investigated the selective elimination of harmonics in optimization-based cascaded H-bridge (CHB) 27-level inverters for hybrid renewable energy sources. This method uses hybrid renewable energy sources such as solar photovoltaics, wind, and tidal turbines with single maximum power point tracking (MPPT). A single MPPT with a Dwarf Mungo optimization (DMO) algorithm is implemented to obtain high performance from hybrid sources simultaneously. The proposed inverter comprises ten semiconductor switches connected to three direct current (DC) sources. The Osprey optimization algorithm (OOA) is used in the 27-level inverter to calculate the switching angles for selective harmonic elimination of pulse width modulation (SHE-PWM). The proposed approach is used on a Simulink platform to assess performance, and its efficacy is demonstrated by contrasting it with an existing approach. The simulation obtained 1.98% THD by using OOA with SHE-PWM. The total cost obtained by the proposed method is 40.03$, and the computational time for DMO and OOA is 1 s and 1.2 s at the 100th iteration. The experimental validation is established using a dSPACE RTI1104 controller to validate the proposed method. The experimental results obtained 1.99% of harmonics with the same output voltage as the simulation. [ABSTRACT FROM AUTHOR]

This paper presents a new controller based on the Lyapunov theory used in a stand-alone photovoltaic (PV) system. The proposed system does not include a pulse width modulation (PWM) controller unlike a traditional one. The quadratic converter including one controllable switch is modeled as a switching system which allows us to propose a switching rule that can be used to control the converter. This part assures the stability of the operating point at any desired voltage value. To determine the operating point that allows to extract a maximum of power from the system, a double-mode variable step size maximum power point tracking algorithm is included in the controller. The proposed method is a hybridization between the well-known perturb and observe (P &O) algorithm and an operation at a fixed voltage value during fast solar irradiance changes. The performances of the global controller are tested through simulation using Simulink/MATLABTM\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$^{\textrm{TM}}$$\end{document}. It is compared to a classical system with PWM and P &O controllers. The result shows that the proposed controller can harvest up to 15%\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$15 \%$$\end{document} more energy from the PV panel in case of fast solar irradiance changes without significantly increasing the implementation cost. [ABSTRACT FROM AUTHOR]

In this paper, a novel fault tolerant control (FTC) of the SAPF configuration is proposed and evaluated with balanced and unbalanced loads. The FTC operation is used in order to optimize the energy transfer and ensure the security and reliability of the shunt active power filter (SAPF) system. In healthy and failure modes and using detection algorithms, the proposed strategy is able to tolerate the unbalanced load problem and the inverter IGBT fault. To generate the reference harmonic currents, we used the instantaneous active and reactive power (p − q − r) method with the phase-locked loop and pulse width modulation techniques. Simulation results are presented in order to verify the effectiveness of the proposed FTC strategy of the SAPF. [ABSTRACT FROM AUTHOR]

This paper presents a generalized structure of a new three-phase multilevel inverter (MLI) which ensures better performance with the minimum number of components for different applications including DC power supply-based renewable energy sources. The proposed MLI topology is developed in the form of several basic blocks which are individually made of a DC voltage source and a semiconductor switch. All the balanced DC sources required for the proposed inverter are made through a high-frequency magnetic link. The single–phase and three-phase five level (5-L) inverters with the rating of 3.5 and 100 kVA, respectively, are simulated, while a five level (5-L) single-phase inverter is implemented for demonstrating the switching strategy and different operational modes. The rigorous calculations are presented to determine switching losses and conduction losses which are minimum because only three conducting switches are responsible for generating each voltage level during every operating mode. The structure of the aforementioned inverter provides optimized value of total standing voltage (TSV = 5.5Vdc with 5-L single-phase leg) of the system. The proposed inverter offers energy conversion efficiency of 94.84% for 5-L single-phase leg which is significantly enhanced and it also minimizes the equipment ratings as well as overall costs of the entire system. [ABSTRACT FROM AUTHOR]

The paper deals with the application of fuzzy logic in the current-based model reference adaptive system (CB-MRAS) for sensorless induction motor drives using direct torque control with pulse-width modulation. The stability analysis of the selected observer is described in the first part. Fuzzy logic is used to adjust the parameters of proportional–integral (PI) adaption algorithm of the CB-MRAS observer. The description of a laboratory workplace with an induction motor drive and load system is presented in the third part. Comparisons of conventional PI and fuzzy logic-based adaptation algorithms are shown in the paper. The theoretical assumptions of the sensorless induction motor drive are confirmed by the simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper presents the development of a multi-input multi-output bi-directional power converter (MIMO-BDPC) with a digital pulse-width modulation (DPWM) controller for solar photovoltaic (SVP) application. The converter is operated in three modes such as buck, boost, and inverter. The converter uses a minimum number of active components and the DPWM controller controls the switching frequency or pulse period which are reconfigurable for effective synchronous and autonomous operation. The autonomous mode is selected by the controller based on the availability of the power source. The combination of high performance, low cost, and high reliability in a single controller is achieved via this intelligent digital approach. The controller is based on the power and load changes in multiple PWM modes. The Intel Altera Cyclone IV FPGA control will be used for digital PWM. The FPGA is scheduled for parallel data processing with multiple resource blocks. During control, this controller can be reprogrammed dynamically again. This makes the system extremely efficient in the check aspect, reducing time and cost. The proposed MIMO-BDPC is tested with the above-mentioned modes of operation using MATLAB software and also through hardware results. [ABSTRACT FROM AUTHOR]

The performance of a multilevel inverter depends upon design and selection of an appropriate modulation technique. Space vector pulse width modulation (SVPWM) technique offers more flexibility than other pulse width modulation (PWM) techniques. However, conventional SVPWM technique becomes more complex for multilevel inverter because of increased number of space vectors and redundant switching states. This paper presents a design space exploration method of hybrid SVPWM techniques for three level voltage source inverter (VSI) to reduce total harmonic distortion (THD) and switching loss over wide linear modulation range. A new parameter Harmonic Loss (product of weighted total harmonic distortion factor of the line voltage (Vwthd) and normalized switching loss) is introduced as an objective function, and a spatial region identification algorithm is proposed to determine the optimized switching sequences for hybrid SVPWM technique. Two optimized hybrid SVPWM techniques are proposed based on the optimized switching sequences for three level VSI. The proposed hybrid SVPWM techniques are implemented on a low cost PIC microcontroller (PIC 18F452) and applied on an experimental prototype of three phase three level VSI with an induction motor as load. The experimental results are demonstrated to validate the performance of the proposed hybrid SVPWM techniques. [ABSTRACT FROM AUTHOR]

This paper introduces a novel modular active snubber cell for isolated half-bridge converters with ease of control. The novel snubber cell can achieved soft switching for all semiconductors at the proposed converter. The switches in the converter are derived simultaneously by the normal pulse-width modulation signals. The introduced snubber cell has a quite simple structure and ease of control. In this converter, the main switches turn on with zero current switching and turn off with zero voltage switching. Besides, there is no extra voltage stresses on the power elements. The proposed half-bridge DC–DC converter is analyzed in detail and its theoretical analysis is verified with a prototype having 50 A–25 V output values at 80 kHz frequency. [ABSTRACT FROM AUTHOR]

The randomized pulse width modulation techniques are used to reduce electromagnetic interference in power converters by spreading the harmonic energy. Thus, a wider spectrum with lower amplitudes is obtained. Based on the pulse width modulation signal parameters, three main randomized techniques are achieved: the random carrier frequency modulation, the random pulse width modulation and the random pulse position modulation. This paper presents a short review of the different implementation methods. Then, a detailed implementation of the three considered random techniques using Atmega328p microcontroller is detailed. Finally, an analysis of the experimental conducted electromagnetic noise taken from a boost converter is discussed. These results prove that the random carrier frequency modulation approach is completely better than other techniques in terms of electromagnetic noise reduction. [ABSTRACT FROM AUTHOR]

Impedance source inverters (ZSIs) have many advantages like the ability to work as a buck or boost inverter and work with different renewable energy sources and can be applied as a voltage source or current source inverter. The switching circuits of ZSI normally are complicated and hard to be implemented. In this paper, a modified sinusoidal pulse width modulation method for ZSI block is presented based on an optimized mathematical model in order to switch the power components of this inverter. The proposed switching structure can be extended to more than one phase, by using the combination of the step-up converter, ZSI networks with the same switching topology for per phase and a full bridge inverter block in order to present a pure sinusoidal wave in the structure's output especially for resistive and inductive loads which are the real and industrial types of the loads. The Boost converter has been applied in our proposed structure in order to enhance the level of the generated voltages by RESs. Due to the ability to increase the voltage across the wide range, good resistance to electro-magnetic interference, acceptable total harmonic distortion value of the waves and immunity through shoot, this converter can be used extensively in PV systems, cell fuel, wind power and UPS systems. One of the most important specifications of the proposed switching method is working with low and intermediate values of duty cycles for power MOSFETs that can decrease the dynamic losses of the inverter. A wide range of mathematical analysis and simulations have been done to explain the proposed method, and experimental results confirm the theoretical analysis by a 100 W laboratory prototype. [ABSTRACT FROM AUTHOR]

Filterless digital class D power amplifiers usually utilize three-level uniform sampling pulse width modulation (UPWM) technique to convert the digital input signal into a UPWM signal which is used to drive the power stage. Therefore, the spectral estimation expressions for different three-level UPWM signals obtained by modulating the digital signal can be an evaluation tool for signal distortion and electromagnetic interference when filterless digital class D power amplifiers are designed. Based on the time-domain characteristics of three-level UPWM signals, the spectral estimation expressions for six types of three-level UPWM signals are proposed in this paper by using the discrete Fourier transform technique and the frequency response of the zero-order holder. According to these expressions, the relationships among the total harmonic distortion, the pulse repetition frequency and the pulse width resolution of the UPWM signal are studied. A UPWM generator test system based on field-programmable gate array is designed and implemented to measure the spectra of different UPWM signals. The measured results are compared with the calculated results obtained by the proposed expressions to verify the correctness of the proposed expressions. [ABSTRACT FROM AUTHOR]

This paper aims at investigating power conversion system (PCS) and lithium-ion (Li-ion) cells employed in a grid-connected battery energy storage system (BESS). For PCS, the work evaluates the efficiency performance among the four topologies commonly used in power grid using PSIM. The output power, DC link voltage, semiconductor devices' configurations and pulse width modulation method are the four parameters which are set constant in order to obtain a fair comparison among the topologies. From the simulations, it was observed that direct DC–AC inverters (98.3–99.1%) yield better efficiency performance compared to conventional DC–AC inverters (98.1–99.0%). Besides, a Li-ion cell is monitored during its charge and discharge cycles where state of charge is estimated via the combination of Coulomb counting and open-circuit voltage method. State of health is predicted by measuring the battery capacity in an experimental setup which aims to predict battery remaining useful life, hence improving the reliability of a BESS. [ABSTRACT FROM AUTHOR]

This paper proposes an inverter scheme to generate an additional third-harmonic component alongside the fundamental component of the current. The generated third-harmonic component is used to achieve the brushless operation in a wound field synchronous machine (WFSM). Contrary to the traditional schemes used, i.e., dual inverter, single inverter with extra switches schemes, and single inverter with four transistor legs, the proposed scheme comprises a single inverter with three transistor legs that utilizes a modified third-harmonic injection pulse-width modulation. The brushless operation in WFSM requires two windings on the rotor periphery, i.e., harmonic winding and field winding that are interconnected through a rotating diode bridge rectifier. To maximize the usage of generated third-harmonic component, the selection of pole–slot combinations of the machine is carried out considering the winding factors. The proposed inverter scheme is verified in MATLAB, and a 2-D finite element analysis is used to validate the brushless operation of the machine along with its electromagnetic performance. [ABSTRACT FROM AUTHOR]

This paper proposes a tool for the synthesis of the design and optimization of digitally controlled pulse width modulator (PWM). There are three phases for the proposed tool. In the first phase, an accurate transistor level model for 90 nm fabrication technology is generated using MATLAB curve-fitting tool box (Dunbar in Am J Phys 24(6):464-464, 1956) and Cadence Spectre Circuit Simulator, which successfully replicates the transistor performance of Cadence 90 nm fabrication technology. In the second phase, the PWM specification is optimally decomposed among its subcomponents. The optimized design of subcomponents is accomplished via Geometric programming in the third phase. A practical design example in Cadence 90 nm fabrication technology is presented to substantiate the suggested methodology for unified design automation and power optimization. [ABSTRACT FROM AUTHOR]

Direct torque control is considered as one of the variable structure control techniques which are characterized by fast response, simplicity and provide direct control of both electromagnetic torque and stator flux by adequate selection of the inverter switches in each sampling period. In case of multiphase motor drives, the increase in voltage vectors offers flexibility to optimize the selection of the inverter switching states, thereby achieving more precise control of the torque and flux. Nevertheless, the criterion for the selection of the inverter states becomes more complex. This aspect is not considered an issue in the traditional three-phase motor drives but needs to be considered in designing the switching table of the direct torque control of five-phase induction motor. Due to the auxiliary vector plane, the low-frequency harmonics need to be eliminated and full utilization of the dc link voltage is desired. The effects of parameter variation (particularly, stator resistance) on the performance of the direct torque control. It is necessary the addition of parameter adaptation algorithm to compensate this effects. A novel direct torque control of five-phase induction motor using a new switching table combined with an adaptive variable structure observer to avoid the effects of stator resistance variations is presented in this paper. Simulation results provided show the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

By modulating the electric field induced to a human body, it is possible to transfer data wirelessly using the body as a transmission medium. This method is referred to as human body communication (HBC), which has multiple advantages in comparison with the traditional radio frequency (RF) communication. First, it alleviates the traffic load from the radio channels, which are becoming more and more congested, as the number of connected wireless devices increases rapidly. Second, HBC can potentially provide higher security than traditional RF communication since the electric field stays in the vicinity of a human body, which makes eavesdropping more challenging. Third, the attenuation in the HBC frequency band is lower than in bands used by the other radio technologies for wireless body area networks. To improve energy efficiency in HBC, one approach is to utilize a wake-up receiver (WUR). The WUR is continuously listening for a pre-defined wake-up signal, which activates the other electric circuitry (e.g., sensing, processing, and communication). The use of WURs can significantly reduce the energy consumption and increase the lifetime of the sensing applications. In this work, we propose a superregenerative WUR solution which employs self-quenching and loose synchronization method and operating at sufficiently low (1.25 kbps) data rate in order to obtain high sensitivity while keeping the energy consumption low. This enables to achieve sensitivity of −97 dBm for 10 bit error rate while consuming only 40 μW. The details of the design and the performance evaluation results of the proposed solution are in the paper. Also, the paper reports the results of the practical measurements characterizing the impact of the electrode location on the path loss in an HBC channel. The presented results show that the proposed system can potentially enable communication between two any points on the body with low transmit power. [ABSTRACT FROM AUTHOR]

In this paper, a digital current control of a three-phase four-leg inverter based on predictive cost function is studied. Inverters are important for power electronics applications in three-phase four-wire systems, such as active power filters and uninterruptible power supplies. There are many methods for control of inverters, such as pulse-width modulation and three-dimensional space vector modulation. These methods are complex. In this paper, a simple way for current control of a three-phase four-leg inverter is presented. Here, by using a predictive cost function and fixed-point computations, the optimal switching state to be applied in the next sampling is selected. Finally, to evaluate the accuracy of the fixed-point computations, several cases for balanced and unbalanced loading conditions are verified. In each case, the parameter that measured to confirm computation accuracy is total harmonic distortion. [ABSTRACT FROM AUTHOR]

In this paper, a new control strategy for zero-current transition technique is suggested to constant voltage constant frequency sinusoidal PWM inverter. This strategy consists of a resonant arm and auxiliary switches, which are connected to a standard single-phase full-bridge voltage source inverter and also to a proportional integral voltage controller. The main and auxiliary switches can be separately controlled. The suggested strategy is able to reduce switching losses successfully, and also it does not need any snubber circuit. By using appropriate switching algorithms, the strategy can be applied to uninterruptible power supplies, photovoltaic systems and DC/AC inverters as well. In this study, not only the theoretical analysis but the simulations of the suggested strategy have been carried out effectively. From the simulation results, it has been shown that the suggested strategy yields 30% less switching losses and has better performance when compared with the hard switching strategy for the same operating condition, including the conditions of the load and the switching frequency. Eventually, the suggested control scheme verified by the simulation results proves that it can achieve low THD values in addition to less switching losses. [ABSTRACT FROM AUTHOR]

Propulsion system used in applications like electric traction, rolling stock, etc. requires high torque at low speed for starting and climbing and nearly constant power at high speed. Induction machines, which are rugged, reliable, low cost and has less maintenance, satisfy the characteristics of the propulsion and reinstating the traditionally used DC series motor for this purpose. Field oriented control (FOC) of induction machines can decouple its torque control from field control and extended speed range operation with constant power beyond rated speed by field weakening (FW). It is desirable to retain maximum torque capability in the FW region for propulsion applications at high speed. To produce maximum torque that machine could possibly develop at FW region, the maximum inverter voltage and current must be appropriately utilized. This paper proposes an innovative approach to improve the torque capability of induction machine in FW region by modifying the design of induction machine to change the bahaviour of the machine to suit propulsion requirements. Extensive simulation of the design options generated from the design modification has been carried out using MATLAB/Simulink and torque-speed characteristics are compared. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (WEDM) is widely used in aerospace, mold manufacturing, automotive, and other fields. But now, traditional WEDM pulse power contains current-limiting resistor, and its energy utilization rate is low. Meanwhile, discharge energy of WEDM pulse power cannot be accurately controlled, and there is no unified understanding of distribution about discharge energy. In this paper, the pulse power improves energy utilization rate by removing current-limiting resistor and adopting single-arm pulse width modulation control method which controls peak current and modulates long short-circuit pulse width. Experiments proved that the energy-saving pulse power improves energy utilization rate by, approximately, 67.6 % than traditional pulse power. The paper analyzed a single-pulse energy waveform of the energy-saving pulse power and calculated each spark pulse energy and total energy provided by pulse power. It found that gap spark discharge energy only accounted for about 51 % of the energy provided by the pulse power, and other energy was mainly consumed in switching loss of power switch and parasitic resistance of pulse power. [ABSTRACT FROM AUTHOR]

An indirect field oriented control of a double star induction motor drive with a conventional PI and fuzzy logic controller based on four rules is presented in this paper. To realize a control of this motor, a DC supply and a PWM voltage source inverter (VSI) are introduced. Performance of the proposed control schemes under load disturbances and parameter variations is studied through simulations. The simulation results regarding the speed response with both controllers are presented and discussed. [ABSTRACT FROM AUTHOR]

This paper presents a novel high multilevel inverter topology which is based on the created DC voltage levels at loads of the inverter. The circuit model is demonstrated by explaining the relationship between switches, sources and loads. According to the proposed inverter topology, the number of power switches connected to negative side of DC source is constant on inverter, while the number of power switches connected to positive side of DC sources is increasing. Therefore, linear pulse-width modulation (LPWM) is described for operating switches after pulse-width modulation method is developed to generate the PWM signals. Then, mathematical equations are given when resistive ( R), inductive ( L) and capacitive ( C) loads are connected in series on a 9-level inverter. Finally, the performances of the proposed inverters are observed through MATLAB/SIMULINK simulations after the designed multilevel inverters are simulated. So, 6-level, 9-level and 11-level inverters are compared with voltages, currents and harmonic distortions. Harmonic distortions reduce with increasing level of inverter, while three multilevel inverters are investigated on different modulation indexes. The results demonstrate the satisfactory performance of the inverter and verify the effectiveness of a novel high multilevel inverter topology. [ABSTRACT FROM AUTHOR]

This paper presents a scheme using carrier-based PWM to control the five-to three-phase matrix converter ( $$5 \times 3$$ MC). This scheme is based on the equivalent indirect converter model, which models the converter as two independent stages to perform rectification and inversion processes. It presents a comprehensive solution for linear modulation (LM) and over-modulation (OM) operations. The OM operating region is classified into three different regions based on the choice of the rectifier and inverter stages switching functions. These regions of operation are rectifier-side OM (RSO), inverter-side OM (ISO) and both sides OM (BSO). With these schemes, maximum voltage transfer ratio (VTR) of this converter reaches 1.05 in the LM and 1.19 in BSO mode. These values are the maximum possible VTR that can be achieved in $$5 \times 3$$ MC. The proposed technique has been implemented using a laboratory setup. Simulation and measured results showed the validity of the given analysis. [ABSTRACT FROM AUTHOR]

Based on classical impedance source inverter concept, this paper presents a modified impedance source inverter controlled by different pulse width modulation control strategies for solar PV/battery-powered applications. A brief topology analysis, generalized discussion and design of impedance network elements are presented. Comparison with the classical impedance source inverter is presented. Using simulation, analytical results are presented that ensure stability. The proposed voltage type inverter has reduced inrush current at startup, less capacitor voltage stress and minimum inductor current ripples. DC link voltage boost, reduced total harmonic distortion of output current and voltage, better voltage gain and wide range of output voltage control can be achieved easily with improved power quality. Experimental set-up of the modified impedance source inverter with Field Programmable Gate Array (FPGA) controller has been constructed to ascertain the results. [ABSTRACT FROM AUTHOR]

Considering the traditional power amplifier has the disadvantage of poor reliability and flexibility, a three-level pulse-width modulation (PWM) power amplifier which is based on a novel field-programmable logic gate array (FPGA) algorithm and hardware solution is proposed. The power amplifier can provide various signals flexibly and realize rapid response of the magnetic suspension spindle in micro-electrical discharge machining (EDM). In this paper, the principle of three-level PWM amplifier with half bridge and full bridge power circuit is introduced. According to different functions, the amplifier is divided into four function modules which include PWM signal generator module, voltage signal convert module, bootstrap drive module, and power bridge module. PWM signal generator module is also divided into four sub-modules in term of a new FPGA algorithm. Voltage signals are converted by high-speed photo coupler HCPL-2630. IR2110S chips are applied to drive the half bridge and full bridge power circuits. According to Kirchhoff voltage law, when the period of PWM signals is 50 μs and the duty cycles are larger than 0.76 and 0.665, the average current of half bridge and full bridge are more than 3 and 4 A; however, the ripple of the half bridge and full bridge are still less than 0.25 and 0.2 A, this advantage is suitable for the control system of magnetic suspension spindle. Test results of the average current and ripple are close to theoretical value. The axial response frequency of the spindle can reach 125 Hz, using this power amplifier and the magnetic suspension spindle, micro EDM can be achieved in Z axis with 1.2 mm stroke. [ABSTRACT FROM AUTHOR]

Distinct advantages of the combination of the pneumatic actuated plants with 'on/off' solenoid valves have motivated many researchers to conduct research in this scope. Pulse-width modulation (PWM) is a tool to use such combination in servo tasks. This paper studies the most frequent and well-reported PWM schemes. These PWM schemes have been applied for positioning tasks of the pneumatic actuators using solenoid on/off valves. In this study, the positioning performance of the servo pneumatic system, utilizing different PWM schemes, is investigated through several experiments with step and sinusoidal reference inputs. Rise time, overshoot, and steady-state error, in step input tests, and tracking performance in sinusoidal tests demonstrate the effectiveness of the deployed PWM schemes in the pneumatic system behaviors. Moreover, the closed-loop results demonstrate that the system robustness against the increase of the system's mass is associated with the applied PWM scheme. Based on the open-loop results, two factors are found to be affecting PWM schemes performance, namely, the difference in the cross-sectional areas on each side of the piston and the piston position, in which these factors have not been considered in the design procedure of the former studies. Taking into account the former factor, a modified version of the PWM schemes is proposed. Steady-state errors in closed-loop tests verify the effectiveness of the developed modified PWM schemes. [ABSTRACT FROM AUTHOR]

In this paper, a pseudo-natural sampling algorithm for correcting the harmonic distortion produced by asymmetric double-edge uniform-sampling pulse-width modulation is proposed. The algorithm uses the decomposability of the asymmetric double-edge pulse-width modulation process and the Lagrange numerical differentiation method for calculating the pseudo-natural sampling points to obtain a harmonic distortion correction effect. The computational complexity of the algorithm is low because it requires only three shifts, six additions and three multiplications to calculate each of the pseudo-natural sampling points. A complete experimental system based on a single field programmable gate array was built to verify the effectiveness of the proposed algorithm and to compare it with other reported kindred algorithms. The results obtained show that the proposed algorithm has lower hardware requirements and better harmonic distortion correction than other related algorithms. [ABSTRACT FROM AUTHOR]

The paper is devoted to the development and mathematical modeling of a stabilization system for unstable vertical plasma position in a T-15 tokamak (Institute of Tokamak Physics, NSC 'Kurchatov Institute'). In the second part of the work, we give a comparison of linear systems for stabilization of vertical plasma position for two versions of the location of the fast coil for the T-15 tokamak's horizontal magnetic field (HFC-coil): a) between the toroidal coil and vacuum vessel, b) inside the vacuum chamber. We estimate parameters for control systems with impulse actuator in the pulse-duration modulation mode and relay mode. Our studies were done on a linear model of plasma in the T-15 tokamak obtained by linearizing the plasma-physical DINA code on the quasistationary stage of the discharge. [ABSTRACT FROM AUTHOR]

Before installation, a voltage source converter is usually subjected to heat-run test to verify its thermal design and performance under load. For heat-run test, the converter needs to be operated at rated voltage and rated current for a substantial length of time. Hence, such tests consume huge amount of energy in case of high-power converters. Also, the capacities of the source and loads available in the research and development (R&D) centre or the production facility could be inadequate to conduct such tests. This paper proposes a method to conduct heat-run tests on high-power, pulse width modulated (PWM) converters with low energy consumption. The experimental set-up consists of the converter under test and another converter (of similar or higher rating), both connected in parallel on the ac side and open on the dc side. Vector-control or synchronous reference frame control is employed to control the converters such that one draws certain amount of reactive power and the other supplies the same; only the system losses are drawn from the mains. The performance of the controller is validated through simulation and experiments. Experimental results, pertaining to heat-run tests on a high-power PWM converter, are presented at power levels of 25 kVA to 150 kVA. [ABSTRACT FROM AUTHOR]

The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a-b) reference frame. This is compared and contrasted with the average voltage vector corresponding to the well-known standard two-zone algorithm for space vector modulated inverters. It is shown that the two-zone overmodulation algorithm itself can be derived from the variation of average voltage vector with TCPWM. The average voltage vector is further studied in a synchronously revolving (d-q) reference frame. The RMS value of low-order voltage ripple can be estimated, and can be used to compare harmonic distortion due to different PWM methods during overmodulation. The measured values of the total harmonic distortion (THD) in the line currents are presented at various fundamental frequencies. The relative values of measured current THD pertaining to different PWM methods tally with those of analytically evaluated RMS voltage ripple. [ABSTRACT FROM AUTHOR]

In the automotive industry, aluminum alloy has been recently used to reduce vehicle weight of the vehicle body. Due to the high electrical and thermal conductivities and low melting point of aluminum alloy, however, it is not easy to achieve a high quality of welding. This paper has analyzed the changes in wire melting rate, arc melting phenomenon, and drop size with electrode negative (EN) ratio by applying AC pulse gas metal arc welding to the aluminum alloy sheet welding process. Furthermore, the characteristics of gap bridging have been analyzed and improved from the point of arc melting phenomenon by changing the EN ratio and gap in the welded joint. [ABSTRACT FROM AUTHOR]

Alpha particles, neutrons and laser-beam test results on an integrated pulse width modulation (PWM) controller operating in a DC/DC converter are presented in this paper. The PWM is fabricated on a 600-nm Bi-CMOS technology. Single-Event Transient (SET) derived from a bandgap circuit was amplified by a filter capacitor in the propagation path. Finally, a constant 6-μs SET pulse was observed on PGOOD pin which is a supervisory signal. This glitch caused system resets. Pulsed laser technology was adopted to locate the origin of the SET. 3D TCAD and circuit simulation tools were used to analyze the root cause. System and circuit level hardening approaches to mitigate the SET are also presented. [ABSTRACT FROM AUTHOR]

control-theoretic approach in designing Digital-to-Analogue Converters and Digital Amplifiers which leads to improved performance in Audio and Multimedia applications is presented in this paper. The design involves an over-sampling and a pulse modulation component which is driven by a pulse generation algorithm based on the characteristics of the output filter. The theoretical model results in a family of digital circuits whose operation is verified by computer simulations achieving a performance of Signal-to-Noise Ratio of 147 dB at a switching rate of 90 MHz. Implementation and hardware complexity issues are discussed based on a FPGA realization of the algorithm. [ABSTRACT FROM AUTHOR]

In recent years several discontinuous pulse width modulation (DPWM) methods are reported to improve the performance of AC drives at high modulation indices. It is proved that the performance of the popular PWM methods is modulation index dependent and no single DPWM method provides satisfactory performance over the entire high modulation range. Two popular existing DPWM methods renowned with the names DPWMMIN, DPWMMAX clamp each phase for 120° duration in every cycle of its fundamental voltage. It is observed that only the zero state is different in these two sequences. In this paper, it is proposed that, utilizing these two DPWM sequences and by changing the zero state at any spatial angle γ, where γ is between 0° and 60°, an infinite number of DPWM sequences including the existing DPWM methods and advanced DPWM (ADPWM) methods can be generated which are categorized as 'continual clamping' and 'split clamping' sequences. Using these ADPWM techniques an optimal split clamping sequence-based DTC of induction motor is proposed. With the proposed DTC method it is shown that steady state line current distortion at higher line side voltages is reduced significantly compared with the CDTC as well as conventional SVPWM (CSVPWM)-based DTC. [ABSTRACT FROM AUTHOR]

This paper presents a disturbance observer and adaptive controller design for a direct drive motion control system. An indirect adaptive controller is implemented to achieve desired tracking performance as well as deal with system parameters variation. To reduce tracking errors, a newly designed adaptive feed-forward controller is proposed based on an on-line estimated inverse model of the linear motor drive system. A digital disturbance observer is implemented to be included in the proposed feedback-feed-forward control structure to compensate for the undesired nonlinearity and external load disturbance of the direct drive system. Experimental results show that this control scheme can achieve superior contouring accuracy, disturbance rejection and robustness under the influence of friction and cogging force. [ABSTRACT FROM AUTHOR]