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This paper presents a resonant frequency tuning (RFT) Delta-Sigma (-) signal-transformed pulse density modulation (PDM) class-D converter for inductive power transfer (IPT) applications. The proposed power controller provides a load-adaptable pulse modulation by tracking a zero phase angle(ZPA) and peak-power frequency, i.e. resonant frequency in the primary-side high frequency inverter. The switching frequency is regulated in accordance with the variations of the load and coupling co-efficient between the transmitting(Tx) and receiving(Rx) coils. The output power is controlled by the RFT - PDM which is effective for reducing a low frequency oscillation (subharmonics), thereby the high efficiency power transmission can attain. The essential performances of the proposed IPT power controller are demonstrated in experiment of a 400W-500kHz of prototype, whereby the feasibility is clarified from a practical point of view.

Multi-output inverters have become a key enabling technology to increase surface flexibility in domestic induction heating appliances. The most commonly used power converter topologies are based on electromechanical relays in order to multiplex the connected loads and obtain a proper heat distribution. This solution, which is used in combination with other modulations such as square waveform, relies on the thermal inertia of the pot as it needs long power-averaging periods to reduce the reiteration of the switching noise. However, it presents a significant limitation in terms of acoustic noise, reliability, and thermal performance. To overcome these limitations, complete solid-state inverters that can be operated at higher frequencies are proposed. This change in the design paradigm of the pulse density modulation strategies leads to improved thermal control in the pot and better user experience, but at the same time increases challenges due to design constraints imposed by electromagnetic compatibility regulations. This article analyzes the possibilities of a new mains-synchronized pulse density modulation applied to a flexible induction cooktop that uses a multiple-output ZVS resonant inverter topology. The feasibility of the control strategies has been tested by means of a prototype featuring 12 2-kW induction heating loads.

Pulse density modulation (PDM) is often applied in inductively coupled power transfer (ICPT) systems to improve high-frequency inverter (HFI) efficiency. However, the PDM may cause the inverter output current fluctuation, even interruption for light load or low-quality factor system. This may result in the difficulty for the implementation of soft switching in ICPT. In this article, an improved PDM (IPDM) strategy is proposed by optimizing the distribution of switch sequences. Through the current fluctuation numerical analysis and Fourier decomposition, IPDM can reduce the current fluctuation and improve the system efficiency. The experimental results on a 20 kW ICPT system prototype show that the proposed IPDM strategy reduces the HFI output current ripple coefficient is 40% to 65% lower than PDM, and the efficiency is also improved.

Output voltage control is an important subject in magnetically coupled wireless power transfer (MC-WPT) applications. Conventional control methods for MC-WPT systems use the PI controller. However, this method suffers from three issues: time-consuming tuning work of the PI parameters, increased control complexity due to the needs of the modulator, and poor dynamic performance. To provide an attractive alternative to the PI controller, a novel output voltage regulation method based on finite-control-set model predictive control (FCS-MPC) has been proposed for a MC-WPT system. The proposed method has inherent advantages such as a very intuitive concept, no need for a modulator, and fast dynamic response. Moreover, it can achieve soft switching by constructing pulse-density-modulation-based voltage pulse sequences as the control set. The design and implementation of the proposed controller are discussed in this paper. The proposed control method has been tested on a series-series-compensated MC-WPT system, and experimental results demonstrate the effectiveness of the proposed control method in comparison with PI control methods.

In this study, an induction heating (IH) application is carried out by transferring the maximum power extracted from photovoltaic (PV) panels to the stainless steel with the designed regular and irregular 32 pulse density modulation (PDM) controlled series resonant inverter. The main objective of this study is to analyse the changes in the system due to regular and irregular PDM patterns. Maximum power point tracker (MPPT) is used to control the output power at different solar irradiation values with varying PDM patterns. Regular and irregular PDM control methods are compared in terms of MPPT efficiency, cost, algorithm complexity, logic control structure and current/voltage stresses of the power switches. Zero current switching (ZCS) conditions are provided by using phase locked loop (PLL) technique at all power points of the PV system. The appropriate switching conditions are tracked continuously at resonant frequency, and therefore soft switching is realised. Perturb and observe (P&O) algorithm is used with the aim of tracking the maximum power in PV panels and high tracking efficiency is obtained with PDM‐controlled P&O MPPT algorithm. ATMEL328P‐AU microcontroller is used to control the inverter in the system.

In the study, the maximum power obtained from the photovoltaic (PV) panels with the proposed 32 model pulse density modulation (PDM) controlled serial resonant inverter has transferred to the work-piece (copper and 304 stainless steel) and therefore induction heating has performed. The designed PV powered induction heating system has achieved maximum power point tracking (MPPT) at resonance frequency and under varying solar irradiation conditions. PV simulator is used as a power source for induction heating. Thus, it is provided to monitor the controlled output power. Phase-locked loop (PLL) applications are widely used in induction heating applications to achieve zero voltage switching (ZVS) and zero current switching (ZCS). In many PLL applications, the frequency tracking is too slow and unreliable. Therefore, a sliding mode controller is developed to provide robust and fast PLL. Furthermore, pulse density modulation (PDM) control strategy is developed to work at the resonance frequency for all power levels. The PDM power control is a good solution for the design of high-frequency inverters because of the great reduction of switching losses and electromagnetic noise. In the experimental system, resonance frequency in the system is determined as 37.5 kHz for stainless steel and 39.5 kHz for copper. Perturb-observe (P&O) algorithm is used to track the maximum power in PV panels. Thus, over 99% tracking efficiency has been achieved by the proposed PDM-MPPT algorithm. ATMEL328P-AU microcontroller has used to control the SMC-PLL algorithm and PDM-MPPT algorithm in the system.

A wide operating region of inductive power transfer systems indicates a stable output against large load and coupling changes. In most of the published works, output regulation is achieved by single-side regulation that utilizes either primary-side or secondary-side power converters for load regulation. However, secondary-side regulation tends to have a relatively narrow operating region due to space and cost considerations. Meanwhile, although primary-side regulation may provide a larger operating region, system performance can be degraded due to the needs of secondary-side information. To overcome the drawbacks of single-side regulation, this article proposes a dual-side cooperative output regulation method implemented by burst-mode pulse density modulation. In the proposed method, dual-side cooperative control is established by sensing primary-side current drops caused by secondary-side burst operations and, hence, requires no communication devices. With the proposed method, the system operating region can be effectively extended without sacrificing steady-state performance. Experimental results are provided in this article to validate the proposed method. Singapore Maritime Institute (SMI) This work was part of the research program of Maritime Research Between Singapore (Singapore Maritime Institute) and Norway (Research Council of Norway) under Project SMI2019-MA-02, which was supported by the Singapore Maritime Institute

To improve the efficiency of high frequency inverter (HFI) in inductively coupled power transfer system, pulse density modulation (PDM) is often used. However, the output current of the HFI fluctuates seriously, especially at light load. It affects the stable operation of the system and the implementation of zero voltage switching. In this article, an improved pulse density modulation (IPDM) is proposed to reduce current fluctuation. It applies harmonics pulse to replace the fundamental pulse and zero state, and evenly distributes the switching sequence to reduce current fluctuation. Simultaneously, the best phase-shift angle of harmonics is obtained by using the transient analysis method to further reduce the output current fluctuation. The IPDM current fluctuation is less than PDM and the efficiency become higher at light load by the theoretical analysis, while PDM is better at heavy load. So, a hybrid modulation strategy is applied that IPDM and PDM are used for light and heavy load, respectively. The experimental results show that the HFI output current ripple coefficient is reduced by 15% to 62% and the efficiency is improved at light load.

In this article, a novel method is presented for maximum power point tracker (MPPT) system to increase efficiency. For this purpose, maximum power obtained from photovoltaic (PV) panels by pulse density modulation (PDM)-controlled high-frequency series-resonant converter was transferred to grid by a single-phase inverter. The resonant converter and the single-phase inverter circuits used in the system were analyzed, designed, simulated, and implemented. The designed series-resonant converter was operated at resonant frequency for different solar radiation conditions using the PDM control technique, and therefore the maximum power point was tracked. Soft switching was achieved by continuously tracking the resonant frequency. Simulated and experimental results were presented for 600 W prototype by operating the MPPT converter over 100 kHz. The MPPT efficiency was obtained as 99% and above. The maximum power tracking of the PV panels was achieved using the perturb and observe (P&O) algorithm with PDM technique. The generated PV power was transferred to the single-phase grid by an LCL-filtered inverter. Proportional integral controller was preferred in the control of single-phase grid-tied inverter.

In this study, a solar powered wireless power transmission system is simulated with MATLAB/Simulink. Wireless power transmission systems are the process of transferring electrical energy from the transmitting system to the receiving system without any physical connection. Pulse density modulation technique is used to generate control pulses for Maximum Power Point Tracking for wireless power transmission system. While the drive system is operated under soft switching conditions, it is able to follow the maximum power point in photovoltaic panels with high accuracy.

This paper analyses how constant voltage load (CVL) characteristics impacts the dynamics of Inductive Power Transfer (IPT) systems. Specifically, it is demonstrated how modulation strategies relying on elimination of voltage pulses, such as Pulse Density Modulation (PDM), can behave completely different when applied to systems with a CVL instead of a constant resistance load (CRL). The critical oscillation frequency caused by the CVL characteristics is identified from a linearized state-space model of the system, showing that large current/power oscillations can occur due to low damping when this oscillation frequency is excited by the PDM pattern. To solve these issues, an enhanced PDM based on delta-sigma modulator is applied to reduce the excitation of the oscillation mode, which limits the current/power ripple to a certain extent. Moreover, a sending current feedback control method is proposed in this paper, which adds phase shift modulation with limited phase shift angle to the PDM when oscillations are excited. Effectiveness and feasibility of the proposed method are validated by simulations and experimental results from a small-scale laboratory prototype.

In this study, the variable speed wind energy conversion system using permanent magnet synchronous generator is operated at the maximum power point at different wind speeds. The designed system consists of a wind turbine, a permanent magnet generator, three phase rectifier, a series resonant converter and a load. Operation at the resonant frequency for different power values has been made possible by using the pulse density modulation (PDM) method. System operates at the resonant frequency. The power switches operate in soft switching conditions. Results show that zero current switching conditions can be achieved for different wind speeds and maximum power point (MPP) of the wind generator is tracked with soft switching.

This work presents the first solar cell (SC)-powered biofuel cell (BFC)-input biosensing system with hybrid pulse interval modulation (PIM) and pulse density modulation (PDM) LED driving capability for stand-alone RF-less continuous glucose monitoring (CGM) contact lenses, which allows diabetes patients to obtain CGM level information without any external devices. Power supply from on-lens SCs can eliminate the necessity of wireless power delivery, and LED implementation can eliminate the necessity of wireless communication. By employing the BFC-input approach instead of using a power-hungry potentiostat, power consumption was reduced. The measured power of 28 nW/144 nW at PIM/PDM mode with a 0.31 V/0.39 V supply voltage can be managed by the on-lens SCs, enabling a fully stand-alone operation under office-room ambient light.

In this study, secondary side controlled (SSC) inductive power transfer (IPT) system is presented. In order to improve efficiency performance of the IPT system, pulse density modulation (PDM) is applied to the switches of the SSC rectifier. Since the operation frequency of IPT system is fixed in PDM control, soft switching conditions can be achieved for all semiconductor devices. In addition, the output regulation can be performed without communication modules. The performance of PDM control compared with phase-shift modulation (PSM) and frequency modulation (FM) methods by simulation. According to simulation results, the efficiency of the PDM control is obtained approximately 2% higher than the PSM and 4% higher than the FM control method at the 25% load condition.

This paper proposed the operation of switched-capacitor-based resonant converters with pulse-density modulation. The pulse density modulation inserts an interval periodically where a zero-average free-oscillating resonant current flows. The free-oscillating current ensures all MOSFETs operate with ZVS transition, and the interval reduces the equivalent switching frequency. Thus, it is possible to operate the SCRC with a negligibly small switching power loss and to reduce the resonant inductor core loss. The capability of maintaining ZVS transition distinguishes pulse-density modulation from the well-known burst-mode control method. The burst-mode operation always suffers from the unavoidable turn-on switching losses to stop and restart the resonance. The experimental results using a 3-kW prototype compares the performance of these two control methods. The pulse-density modulation is capable of reducing the loss of as much as 40% compared with burst-mode control and exhibits an efficiency over 99% in a wide range starting from 14% of the rated power.

This paper proposes an improved pulse density modulation (IPDM) power control method for semi-bridgeless active rectifier (SBAR) in inductive power transfer (IPT) system. In this method, the input voltage pulse sequences of the SBAR can be distributed more evenly compared with the traditional PDM, so the output voltage ripple can be reduced effectively. Besides, for multiple paralleled pickups, the interleaved IPDM is developed to further suppress the output voltage ripple. In addition, the characteristics of zero-voltage switching and zero current-switching for the SBAR's switches can also be achieved in the proposed IPDM method by synchronization control for the gate signals of the SBARs. The experimental results on a 30 kW IPT prototype with four paralleled pickups verified the proposed method.

The high-power ultrasonic cleaning system is used in the manufacturing of clean product contaminants. The pulse density modulation (PDM) switching strategy is more efficient for cleaning the rough surface of equipment. This paper proposes a novel pulse density modulation duty cycle stepping (PDMDCS) method that incorporates a proportional–integral–derivative controller and fuzzy logic for the mechanical resonance frequency tracking and PDM duty cycle stepping for ultrasonic cleaning system power control. The experimental results show that based on the same hardware architecture, the proposed PDMDCS method increases the power control range and resolution of power control without adding more hardware that compares to mechanical resonance frequency control method.

In recent years, induction heating (IH) applications aided by electronic power control have gained significance. Particularly, for cooking applications, an appropriate control technique is required to feed power from a single source to multiple loads with minimum switching losses. Additionally, when multiple loads are used, it requires independent control and operation for each of the loads. The main idea of this work is to develop a single-stage AC-AC converter topology to feed power to multiple loads independently with a single source, with a reduced number of switching devices and with minimum switching losses. The proposed topology uses a frequency bifurcation concept to feed power to multiple loads by placing the transmitting coil and work coil at a distance of 3 cm. The source is resonated at a 25 kHz switching frequency, with the designed bifurcated frequencies of 20 kHz and 33 kHz. The resonant capacitors are appropriately chosen to operate at those frequencies. For real-time applications, simultaneous and independent power control are inevitable in multi load-fed IH applications. This is achieved through a pulse density modulation scheme with minimum switching losses. The simulation of the proposed system is performed in MATLAB/Simulink, and also the 1 kW system is validated using a PIC16F877A microcontroller. The real-time thermal variation in the load is also recorded using a FLIR thermal imager. The experimental and simulation results are observed, and the obtained efficiency of the system is plotted for various duty cycles of pulse density modulation control.

This paper presents a control method to eliminate the common mode voltage created by a three-phase, four-leg voltage source inverter. Wide band gap devices create an opportunity to use pulse density modulation instead of pulse width modulation, with two inverter poles switching high and two low at all times to eliminate common mode voltage without increasing losses. In this way the common mode voltage is always zero to the precision that the inverter legs can be simultaneously transitioned. The novel control strategy also produces balanced output voltage to meet the power quality requirements in MIL-STD-1399 when the load is unbalanced. Elimination of the common mode voltage removes the need for a large common mode choke to suppress circulating currents and to meet the conducted emission limits in MIL-STD-461G. A state space model is derived, used to compute the inverter reference voltages and to simulate the proposed control system. Experimental measurements on a laboratory prototype validate the model and verify the functionality of the novel control method.

Dynamic wireless power transfer (DWPT) for electric vehicles (EVs) is an innovative technique that enables the EVs to enhance the driving range and reduce the capacity of the battery. The receiving current control is important to prevent the battery from overcharging. In this paper, the receiving current control using an active rectifier is focused on. Pulse density modulation (PDM) is effective in terms of the switching loss in the rectifier compared with pulse width modulation. In the previous papers regarding to the PDM, the operation is evaluated in stationary WPT systems. In this paper, the transmission energy efficiency of the receiving current control with the PDM is evaluated using a high-speed rotational testbench for the DWPT. In addition, centralized PDM (CPDM) and distributed PDM (DPDM) are experimentally compared. As a result, it was confirmed that the current control performances using the CPDM and DPDM are the same in spite of the mutual inductance dynamic change at 40 km/h. The energy efficiency of the DPDM was 3.3–7.9% higher compared with one of the CPDM because it can reduce the filter current and loss in the filter inductance. Therefore, the DPDM is effective for the receiving current control of the DWPT system.

In this paper, a pulse density modulation (PDM) control for an inductive power transfer (IPT) converter with double-sided LCC compensation topology is proposed. The PDM control method achieves the output voltage regulation and the inverter works very close to resonant frequency for all load condition. A simulation study is carried out for the IPT converter using PDM control. Then, the obtained results are compared to variable frequency control (VFC) method. According to the comparison results, PDM control provides the operation of the IPT converter at resonant frequency in a wide range load condition. The overall efficiency of the IPT system with PDM is improved by 3% compared to VFC at the half load condition.

Induction heating enables the conversion of electrical energy to thermal energy with a fast, high conversion efficiency and the ability to partially heat be used in a wide variety of welding industries. Conventional diode/SCR rectifiers and mid-frequency/high-frequency resonant inverters used to power conventional induction heaters will have low efficiency, low input power factor, high THD input current. Recently, a research has been done on a current fed three phase-three switch PWM rectifier, producing high power factor but also high current THD. The paper proposes a voltage fed three phase-three switch PWM rectifier with simple structure and control to achieve high power factor and lower current THD. A new variable pulse density modulation without online calculation has been proposed. The preliminary simulation and experimental results verify the feasibility and efficiency of the proposed configuration.

Four-leg inverters are widely used to mitigate the effects of unbalanced three phase supply and unbalanced three phase loads. The most popular switching signal generation technique for four-leg inverter are 3D Space Vector Pulse Width Modulation (3D SVPWM) schemes. In this paper a 3D Space Vector Pulse Density Modulation (3D SVPDM) scheme for two-level four-leg inverter is proposed. The proposed 3D SVPDM scheme uses abc coordinate system. The oversampling and noise shaping property of Pulse Density Modulation (PDM) provides better harmonic performance than SVPWM schemes. 3D SVPDM does not have any complex timing calculations. The proposed scheme can be used for active power filter applications. 3D SVPDM is validated through simulation by using Matlab/Simulink software. The simulation results of 3D SVPDM are compared with 3D SVPWM scheme and it is observed that 3D SVPDM shows better total harmonic distortion (THD) characteristics.

This paper presents a soft start-up strategy of pulse-density-modulated series-resonant converter for induction heating application. The pulse-density modulation (PDM) technique is widely used in converters based on voltage-source series-resonant inverters (SRIs) to control the output current or power. However, during a start-up process, PDM has some disadvantages both in inrush current limiting and providing a zero-voltage switching operation of SRI transistors. In the paper, different PDM techniques are considered and basic moments of PDM using within the start-up process are analyzed. A new soft start-up strategy of PDM converter for induction heating application is proposed. The main features of the proposed strategy include an interleaved or a stepped PDM control, an initial combination of PDM at the beginning of the start-up process, and an operating algorithm during the start-up process. The proposed strategy was verified by a 2.5 kW experimental setup of the pulse-density-modulated interleaved converter with an operating frequency from 50 kHz up to 100 kHz. Experimental results confirm the effectiveness of the proposed start-up strategy and show that the maximum current amplitude within start-up processes exceeds the maximum steady-state current amplitude by no more than 30%.

In this work, the secondary side controlled wireless power transfer (WPT) converter using a LC/S compensation topology is proposed. The constant voltage charging control mode of the proposed converter is evaluated based on high efficiency. In the secondary side, a semi-bridgeless active rectifier (SBAR) is used for the output voltage regulation. In order to improve the efficiency performance of the converter, the pulse density modulation (PDM) control method is applied to the switches of the SBAR. The primary switches operate at the constant operation frequency as independent of the secondary side. There is no communication needed between primary and secondary sides of the proposed converter. Besides, the switches of the SBAR operate with soft switching. The basic principles of the LC/S compensation network and SBAR topology are presented with steady state analysis. The PDM control strategy applied to the switches of the SBAR is discussed. In order to validate the performance of the proposed converter, a prototype is built with 8 cm air gap coreless coupling coils. The input voltage of the converter is 30 V, and its maximum output power is 60 W. The maximum efficiency is achieved as 85.26% at full load condition during CV regulation. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Medical implantable devices can use photovoltaic (PV) energy harvesting to extend battery life span and increase their performance. The power conditioning and management circuitry is essential not only to regulate the voltage requirements of the load but also optimize the output power of PV cells. However, the optical losses due to the skin and the device characteristics of the PV cells are rarely analyzed before chip fabrication. This inevitably leads to sub-optimal system performance in in-vitro or in-vivo tests owing to the varying PV output characteristics. To address this problem, we use the finite-element-method (FEM) to analyze the optical and physical performance of the PV cell under the skin, and then export the model into the p-spice simulator for circuit-level implementation. We further demonstrate a 1:2 cross-coupled DC-DC converter using pulse density modulation for load regulation control to meet the loading requirement. In this work, the PV cell can achieve an 18% of efficiency, and the power conditioning circuit can provide an 84% of end-to-end efficiency.

Space vector based pulse density modulation (SVPDM) scheme exhibits variable switching frequency resulting in broad and continuous frequency spectrum. The spectral spreading results in harmonic performance improvement and decline of motor acoustic noise. A space vector based pulse density modulation scheme with reduced computational complexity for multilevel inverters is presented in this paper. Reduced computational complexity is achieved in such a way that the entire computation process takes place in 120° coordinate system itself without requiring the conversion to 60° or 90° systems. The scheme makes use of the concepts of sigma delta modulation and vector quantization for generating the output switching vectors for inverters. In the proposed scheme, nearest three vectors enclosing the reference vector is identified by comparing the instantaneous values of three phase reference signals. Out of the three surrounding vectors, the vector with minimum Euclidean distance is selected as the output switching vector. Simulation as well as experimental results are utilized for validating the scheme.

This paper presents a method of control known as maximum efficiency point tracking (MEPT). This method of control is used for wireless power transfer (WPT) systems to provide maximum value of efficiency against load variations and coupling with achieving power demands of the system. In traditional MEPT systems, on both transmitting and receiving sides dc/dc converters are used in order to achieve maximum efficiency and for the regulation of output voltage. But this arrangement increases the complexity of network with increasing power loss. Some implementations lead to new problems like hard switching, large dc voltage ripples and low average efficiency. An implementation of MEPT based on pulse density modulation is explained in this paper which removes all the drawbacks in existing implementation. A PDM circuit is used in both transmitting and receiving side to achieve maximum efficiency. A simulation circuit is built in matlab in this paper to get maximum efficiency. By varying load resistances and pulse densities in the matlab Simulink circuit an efficiency and output voltage is checked By comparing the results of existing MEPT implementation with this simulation circuit of WPT using PDM it achieved efficiency upto 83% for various load resistances and pulse densities.

The measurement of the junction temperature of light emitting diodes (LEDs) has been crucial for the thermal management. It is more important for the applications of the ultra-violet light emitting diode (UVLED) with a low efficiency generating more heat and with the PWM-mode current driving at a higher peak current than the one with the DC-mode current driving. In this paper, the dynamic junction temperature of the UVLED with 365nm peak wavelength is characterized by the empirical modelling for the PWM-mode current driving modes with different duty cycles and periods using T3ster with the time-resolved measuring based on the JESD 51-14 and 51-51 for the DC-mode current driving. The PWM-mode response of the junction temperature rise and its fluctuation are normalized by the DC-mode response and its PWM-mode response respectively in terms of duty cycles (ranged from 10~90%) and periods (ranged from 0.1msec. to 1sec.). The DC-mode junction temperature rise with respect to applied dc currents can be direct measured by T3ster. Based on the DC correlation, the PWM-mode correlations with the power-exponential function of the normalized peak junction temperature rise and its fluctuation is established. With the proposed correlations, the normalized mean junction temperature rise as the average of the dynamic junction temperature rise over a period is found. The normalized thermal resistances of the peak, mean, fluctuation are inferred from the correlations. Furthermore, the maximum permissible pulse current is able to be determined based on the maximum rating of the DC junction temperature and the consideration of current crowding. Finally, the pulse density modulation (PDM) mode of current driving is also discussed. Those successful empirical modeling is helpful for the thermal design and thermal management for applications of UVLED with PWM-mode driving.

Existence of zero sequence voltage induces flow of bearing current, causing motor bearing failure, motor winding insulation breakdown and electromagnetic interference in induction motor drive. A space vector based pulse density modulation scheme to eliminate zero sequence voltage in an induction motor drive is presented in this paper. The scheme operates by switching only those vectors of five level inverter which do not generate zero sequence voltage, resulting in a 300 tilted three level space vector diagram. In the proposed work, sub-hexagon containing the reference vector is mapped to inner three level vector space. The mapped reference vector is vector quantized in the sigma delta modulator to obtain switching vectors of inner three level sub-hexagon. Actual switching vectors are calculated by the process of reverse mapping. Proposed scheme operates efficiently in both linear as well as over-modulation region. The scheme includes additional benefits such as absence of minimum pulse width problem, non requirement of complex duty ratio calculations and better harmonic performance, which pertains to space vector based pulse density modulation. The scheme is experimentally verified with 5 HP dual inverter fed open end winding induction motor drive and the results obtained validates the scheme.

Insulated DC-DC switching power supplies have been using a magnetic coupling method using a transformer for several decades. Transformers have excellent properties as a material that can change the voltage while insulating. On the other hand, it can be considered that there is a limit to the reduction in size and weight with increasing switching frequency. Therefore, we are interested in the insulation type converter by the capacitor coupling. The principle of the capacitor insulation method was introduced in 1994, but it was pointed out that the problem of noise that occurs when the power device is turned on and off. After that, a case where noise was suppressed by using a series resonant circuit of a capacitor and an inductor was reported. However, it had no means to control the output voltage, and had the problem that fluctuations in the input voltage would directly cause fluctuations in the output. Therefore, we maintain “resonance state” by providing “two sets of LC resonance tank circuits corresponding to the resonance frequency” and changing the operating frequency for ON width pulse of fixed width (pulse frequency modulation or pulse density modulation). We propose that the output voltage can be controlled while. The voltage control characteristics are analyzed using Spice Simulation, and the Co-relation with the experimental value is confirmed. By using frequency/density modulation, the inverter is always switched at the current zero crossing point, enabling Noiseless switching. Regarding the possibility, we will analyze the switching characteristics due to the deviation from the resonance point by using ADS; Electronic Design Automation tool, for the noise that may occur in the actual PCB (circuit pattern), and show the results.

Common mode voltage is responsible for the flow of bearing current through the motor bearings, leading to motor bearing damage, electromagnetic interference and motor winding insulation breakdown in induction motor drives. Common mode voltage elimination by space vector based pulse density modulation scheme is proposed in this paper. In the proposed scheme, the inverter switching vectors having zero common mode voltage among the nearest three switching vectors of integrated error vector is selected as the code vector. The scheme embeds the benefits of space vector based pulse density modulation such as avoidance of minimum pulse width problem and non-requirement of complex timing calculations along with better harmonic performance. The proposed scheme is experimentally implemented for a five level dual fed induction motor and the results obtained confirms the elimination of common mode voltage.

Plasma-assisted ammonia synthesis has been one of the promising alternatives for building a sustainable ammonia production infrastructure. This study improved this process by introducing an in situ catalytic absorption mechanism using magnesium chloride. Other than its catalytic functions, the absorption mechanism involved two pathways of forming Mg3N2 and Mg(NH3)6Cl2. Meanwhile, the pulse density modulation (PDM) was introduced to improve the energy performance of the system. The series of efforts improved the plasma energy efficiency of the system and achieved the highest value of 20.5 g/kwh.

A differential quantizer-based error feedback modulator intended for digitizing analog signals and its comparison to the traditional interpolative sigma delta analog-to-digital conversion is presented in this brief. The differential quantizer-based error feedback modulator also falls under the class of noise-shaping data converters. This newly introduced technique replaces the integrator with a differential quantizer to achieve noise-shaping characteristics. Thus, integrator associated non-idealities, loop-stability issues, and optimization of the integrator scaling coefficients is no more a concern. Differential quantizer-based error feedback modulator technique can perform well in high-precision and low-power applications. Behavioral-level simulation results demonstrate the mathematical equivalence of the differential quantizer based error feedback modulator technique with interpolative sigma delta modulator technique and confirms its novelty, theoretical stability, and scalability to higher order. The circuit level feasibility and effectiveness of the proposed architecture is verified in a 45-nm CMOS process using a 1-V supply with a power consumption of 0.22 and 0.5 mW for the first and second order modulators, respectively.

In this letter, a hybrid modulation concept consisting of three-level space vector modulation (3L-SVM) and phase-shifted pulse width modulation (PS-PWM) is proposed for five-level active-neutral-point-clamped (5L-ANPC) converter. Under this concept, a simpler 3L-SVM plus PS-PWM scheme is applied to realize 5L modulation, instead of using complex 5L-SVM. The control of neutral voltage, flying capacitor voltage, and the improved dc voltage utilization are all implemented. With the help of the proposed concept, well-developed 3L-SVM schemes can be directly applied to the 5L-ANPC converter, which significantly simplify the gating signal generation. This concept can also be applied to other hybrid clamped 5L converters with two dc-link capacitors. It provides a unique solution, which utilize lower level SVM scheme to control higher level multilevel converters.