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Recently, multiphase drives have emerged as a notable alternative for three-phase drives in several domains, including electric marine propulsion, locomotive traction, and high-power industrial applications where fault tolerance and high reliability are required. This study uses a graphical approach to develop a new carrier-based Pulse-Width Modulation (PWM) that reduces the root-mean-square value of the output current ripple in two-level multiphase inverters with an odd number of phases. The optimization process calculates the optimal common-mode voltage for each switching period. Numerical models and experiments with five- and seven-phase inverters demonstrate the effectiveness of the developed PWM technique, which can reduce the number of commutations while obtaining the lowest output current ripple.

This article presents a 6.78 MHz single-stage wireless power transfer (WPT) receiver (RX) using 0X/1X regulating rectifier with improved voltage mode (VM) delay compensation for implantable medical devices (IMDs). The regulation of 0X/1X modes is achieved through pulse width modulation (PWM), with the frequency set at 1/16 of the carrier clock to ensure circuit stability and enhance power conversion efficiency (PCE) under light loads. VM delay compensation has the advantage of power consumption. However, the traditional VM on-delay compensation may become ineffective because a large voltage pulse will occur on the RX side input when the circuit delays increase. Therefore, an improved VM on-delay compensation method is proposed. Coarse compensation for on-delays can be achieved by reusing the control signal generated from off-delay compensation loop, as off-delay compensation processes will not be influenced by on-delay compensation processes. It allows the on-delay compensation loop to function normally and finely compensate for on-delays. The proposed rectifier is designed in $0.18\mu $ m CMOS process. It can achieve output voltage management of 1.8V. Comparing with other regulating rectifier, the proposed rectifier has a fast transient response of $14~\mu $ s and a small chip area of 0.91 mm2. The simulation results indicate that this rectifier can attain high PCE of 84.6% in light load ( $500\Omega $ ) and peak PCE of 93.5% in heavy load ( $50\Omega $ ). The high voltage conversion ratio (VCR) of over 93% is also achieved under the large circuit delays.

Single-stage differential mode inverters (DMI) have been extensively utilized in three-phase grid-connected systems due to several advantages, such as few semiconductor devices resulting from their simple and modular configuration. Nevertheless, the modulation and control strategy require further enhancement to enable more efficient power conversion across various operations. Therefore, this paper introduces a detailed analytical model of the SEPIC-DMI, leading to the development of a hybrid discontinuous modulation scheme pulse width modulation (DMS-PWM), which incorporates zero voltage switching (ZVS), denoted as Hybrid DMS-ZVS-PWM approach. In the proposed strategy, the duty cycle of SEPIC-DMI is zero for one-third of the grid frequency cycle, which leads to minimizing conduction and switching power losses. Moreover, the voltage stress on the components is significantly reduced due to DMS-PWM. For ZVS, a simplified active-clamp circuit is proposed and designated using a single switch and two small capacitors. The proposed active-clamp circuit is integrated into the SEPIC-DMI to verify SEPIC power switches’ ZVS and zero current switching (ZCS). The ZVS/ZCS improves the inverter efficiency by major minimization in power losses. The mathematical derivations and performance measurements (simulation and experiment) are provided to show the superiority of the proposed hybrid DMS-ZVS-PWM method. The peak efficiency of SEPIC-DMI is enhanced from 90% to 94%, and the voltage stress is curtailed in all components with 13%.

The human intervention free bidirectional efficient energy exchange between the grid and Electric Vehicles (EVs) relies on effective bidirectional power flow control in Wireless Power Transfer (WPT) system. This essential bidirectional control feature enables the grid to charge the EV’s battery and, during surplus energy periods, allows the EV to feed power back to the grid. This capability facilitates the implementation of Vehicle-to-Grid (V2G) functionalities. Implementing this bidirectional flow requires sophisticated modulation techniques to ensure seamless power transfer and optimize overall efficiency. In comparison to pulse width modulation, pulse density modulation (PDM) proves more effective in minimizing switching losses in the converter. PDM efficiently manages the amplitude of high-frequency pulses generated by the inverter and converter systems for WPT applications. However, the PDM techniques are not effectively investigated in the bidirectional wireless power transfer system (BWPT). In this paper, Fuzzy Logic Controlled Pulse Density Modulation (FLC-PDM) approach for the BWPT is proposed for the first time. This approach uses dual side pulse density control for high-frequency converters with the fuzzy rule base to adjust the pulse density and duty ratio based on the load demand. The proposed approach aiming to optimize efficiency across diverse loads and regulate the output voltage and provides effective control approach for the BWPT system. This method ensures constant switching frequency output voltage regulation and delicate shifting operation for high-frequency converter switches, requiring no additional components. The circuit simulations and hardware prototype testing are performed for the 3.7 kW power rating and 85 kHz operating frequency to validate the proposed FLC-PDM approach for the BWPT circuit and yielded an efficiency over 93% across diverse load resistances and pulse densities.

As power demand from electric vehicles and digital loads increases, the use of direct current power supplies is increasing. As a result, the application of microgrid utilizing various distributed power systems is expanding. As demand power and load capacity increase, parallel operation of multiple power converters is required to increase the capacity of power converters used in distributed power systems. Among parallel control methods, load sharing through communication has a significant effect on control performance due to communication speed and reliability. This paper proposes an instantaneous load-sharing parallel control method using a high-speed communication method that can transmit data necessary for load-sharing every control cycle. The proposed communication method uses enhanced PWM and capture communication using a DMA module to compensate for the shortcomings of the existing method using PWM and capture functions. Whenever the master voltage controller is executed, the data required for parallel operation is updated, and by transmitting this data to the slave, instantaneous load sharing control with high speed response is possible. We explain the communication and system architecture of the proposed method and present the communication protocol specifications and design. The performance and validity of the proposed instantaneous load sharing parallel control method were verified through simulation and experiments.

In this article, an active rectifier with pulse width modulation (PWM) mode on- and off-delay compensation technique is proposed. Conventional delay compensation modes: current mode, voltage mode, and delay-based mode are discussed respectively. Also, the adaptive delay compensation technique and potential disturbance problems are analyzed. To achieve wide and flexible delay compensation range, the proposed rectifier adopts current mode delay compensation methods to eliminate on- and off-delay. Moreover, PWM mode feedback loops are built to compensate circuit delays adaptively under various process, voltage, and temperature (PVT) and loading conditions. Compared with previous works, the proposed PWM mode technique converts the fluctuant error voltages into the fixed duty cycle signal in each cycle, avoiding the disturbance on compensation current and even error flips of comparators. The stability of the current compensation is improved. The proposed active rectifier was designed and fabricated in $0.18\mu \text{m}$ CMOS process. Both TX and RX coils are designed and fabricated on printed circuit board (PCB), and the diameter is limited below 3cm. Measurement results show that, with the input sine voltage amplitude ranging from 1.5V to 2.4V and 2MHz operating frequency, the peak power conversion efficiency (PCE) achieves 91.7% under $200\Omega $ loading resistor and the peak voltage conversion ratio (VCR) achieves 93.7% with $500\Omega $ loading resistor. The maximum output power reaches 57.6 mW. Compared with the case with no PWM mode delay compensation, the measurement PCE and VCR are improved by at least 9%. The proposed rectifier achieves better dynamic performance and is suitable for wireless power transfer (WPT).

This paper proposes a bidirectional three-level T-type LLC resonant DC-DC converter operating with phase-shift control, which is simple and effective, variable frequency modulation to perform soft switching in a wide voltage ratio range and light loads, and pulse width modulation to reduce reactive circulating current. In this combined modulation method, three control parameters: switching frequency, the duty cycle of switches in the vertical arms, and phase shift between primary and secondary switches, are changed depending on the voltage conversion ratio and load. The circuit operates as LLC resonant in forward operation and series resonant in reverse operation. Thus, LLC and series resonant analyses of the proposed converter, operated in continuous conduction mode and buck mode, are presented. A simplified frequency domain analysis, including all harmonics, is used in the theoretical calculations. Thus, the control parameters are accurately calculated for forward and reverse operations. The current, voltage, and power formulas in the working principle of the converter are derived, and an analysis of the control parameters and zero voltage switching region is performed. Soft switching analysis is done by considering the junction capacitor of the MOSFET and the dead time. The theoretical performance of the proposed modulation method has been verified with a 2 kW prototype. Soft-switching and loss analyses of the proposed converter have also been investigated under different load conditions and voltage conversion ratios. The proposed LLC resonant topology and modulation method improved significantly more efficiency than the phase-shifted modulated T-type converter under 30-100% load conditions.

The use of pulse width modulation (PWM) to drive permanent magnet synchronous motors (PMSM) inevitably creates current harmonics. The generated current harmonics create harmonic components of the electromagnetic force, causing noise and vibration in the PMSM and affecting the applied system. In this paper, the effect of PMSM’s electromagnetic force on noise and vibration of a reciprocating compressor is analyzed. First, two PMSMs with different electromagnetic forces were designed. As the driving method, space vector PWM (SVPWM) was used, and the experimental current waveform was analyzed. Based on the Maxwell stress tensor method, the electromagnetic force of the PMSM was calculated and the noise/vibration characteristics were analyzed. Compressors were manufactured with two PMSMs with different electromagnetic forces and the noise/vibration test results were compared. The electromagnetic force of PMSM affected the noise of the compressor, especially in the domain of twice the carrier frequency, but did not affect the low-order vibrational displacement of the compressor. The finite element analysis method was used, and it was experimentally verified with the manufactured motor and compressor.

Parallel operation by multiple power converters is typical in microgrids. The communication method for parallel control mainly applies MODBUS RTU (Remote Terminal Unit), and the control performance largely depends on the communication speed. This paper proposes a new communication method that enables fast and accurate communication between master and slave systems combined in parallel using the PWM and capture functions of DSP used as the power converter controller. In the proposed communication method, the transmitting side uses the PWM function of DSP to generate a pulse waveform whose pulse width changes according to the reference command and transmits it to the receiving side. Suppose the capture function of the receiving side DSP is set to the time difference rising and falling edge mode. The set event occurs when the capture signal is detected and initializes the counter value to zero. At this time, it detects the counter signal and receives data. We explain the proposed communication method’s principle, characteristics, and noise-canceling method and evaluate the accuracy and stability through data transmission and reception experiments. Finally, three 10kW single-phase electronic loads are connected to the R, S, and T phases to form a three-phase electronic load, and a master and two slaves are designated. The validity of the proposed communication method is verified through the current control response according to the command.

This paper presents a driving circuitry system for high-resolution, pixelated-LED automotive headlamps. The system consists of an array of pixel drivers, and a row/column driver suitable for an active-matrix array configuration with the individual dimming control capabilities on each pixelated-LED. An asynchronous serial communication protocol is introduced to minimize the number of data transmission interface signals between the row/column driver and pixel drivers. The proposed pixel driver is designed to drive each pixelated-LED with constant current and pulse width modulation (PWM). It contains a memory cell for dimming data, and a sample-and-hold driver stage to minimize the static power consumption of the pixel driver. The proposed system has been fabricated by using a 0.18- $\mu \text{m}$ CMOS process. The test chip includes a $2\times16$ pixel array with an embedded row/column driver. The functional operation has been verified with an $8\times16$ LED array system prototype.

In the low voltage based renewable systems like PV and Fuel cell applications, the step-up of the output voltage to drive the loads is essential. For this, the integration of switched-capacitor (SC) units with the dc-ac converters will have the potential advantages like improved efficiency, optimal switching devices, small size of passive elements (L and C) as compared with traditional two-stage conversion system (dc/dc converter and dc/ac converter). This paper focuses on a new family of step-up multilevel inverter topologies with switched capacitor integration with dual input voltage sources. With the flexibility of 2 dc sources and switching capacitor circuits, four different topologies have been suggested in this paper with features of high voltage gain, reduced component count, reduced voltage stress and self-voltage balancing of the capacitor while achieving a higher number of levels. A detailed analysis of proposed multilevel inverters has been analyzed with the symmetrical and asymmetrical mode of operations and the associated gain, the number of levels, and other performance indices are presented. An in-depth study of all the topologies has been accomplished in this paper with several comparative studies in terms of components count, voltage gain and cost. The effectiveness and practicability of the suggested topology with 13 level output voltage has been explained by the experimental results obtained from a scale down prototype.

This paper presents a hybrid control strategy which combines the nearest level control technique with PWM control technique on a cascaded H-Bridge Multilevel Inverters (MLI). MLIs have become very popular due to its several advantages in the application areas like industrial drives and grid-connected renewable energy generation systems. With the reduced number of switches, driver circuits, conduction losses, switching losses, voltage stresses, size, and cost of the system, MLI has outperformed its two-level counterpart in terms of power quality issues. Reduction in the Harmonics and consequently the Total Harmonic Distortion (THD) in the output voltage has added to the benefits of MLI. Topological advancements in MLI require a satisfactory output voltage control strategy. In this work, a hybrid control strategy for a smooth and wider range of control of output voltage is proposed. The hybridized scheme enhances the control range of the voltage considerably. Moreover, the THD is also reduced compared to the conventional sinusoidal PWM scheme. A thorough analysis of the scheme has also been presented in the paper. SIMULINK/ MATLAB environment is used for testing the simulation model of the proposed control scheme. This hybridized controlling technique is also simulated for thermal modelling on PLECS software and power loss analysis is performed. The mathematical and simulation analyses are validated on an experimental prototype using a TMS320F28335 DSP controller card. The hybrid scheme has also been tested for a fault tolerant model of the cascaded H-bridge inverter. The performance of the hybrid scheme under different fault condition has also been shown to work satisfactorily.

This proposed work demonstrates the illustration of dynamic performance intensification of a Permanent Magnet Synchronous Motor (PMSM) employed by a PWM controlled inverter which synchronizes with the rotor movement intimation. PMSM are widely hired in electric vehicles since it possesses better dynamic response, improved torque-speed property, and reduced noise, energy-efficient and power factor in comparison with traditional motors. In the present work, it is observed that by few modifications of the position control strategy as good as sinusoidal stator currents response generates less torque ripples. The mathematical model for PMSM is derived from park’s transformation. Further, a maiden attempt is taken to introduce the performance indicator ’sensor angle’ to estimate the rotor position in this strategy. From the established model, the various dynamic behavior of the drive system is determined analytically without and under various load disturbances. Additionally, a particle swarm optimization (PSO) technique is adopted to optimize the performance of the proposed dynamic strategy. An efficient speed control strategy by the variation of DC bus voltage is achieved which is equivalent to the armature voltage control of the conventional dc machine. Further, efficient and simple control circuitry of the voltage source inverter (VSI) is obtained in this strategy. To verify the efficacy of the proposed algorithm, necessary tests are carried out in a real-time setup. Therefore, an improved control strategy obtained from the simulation and an experimental approach meets the dynamic behavior employed in light weight electric vehicles.

Selective harmonic elimination (SHE) technique is used in power inverters to eliminate specific lower-order harmonics by determining optimum switching angles that are used to generate Pulse Width Modulation (PWM) signals for multilevel inverter (MLI) switches. Various optimization algorithms have been developed to determine the optimum switching angles. However, these techniques are still trapped in local optima. This study proposes an opposition-based quantum bat algorithm (OQBA) to determine these optimum switching angles. This algorithm is formulated by utilizing habitual characteristics of bats. It has advanced learning ability that can effectively remove lower-order harmonics from the output voltage of MLI. It can eventually increase the quality of the output voltage along with the efficiency of the MLI. The performance of the algorithm is evaluated with three different case studies involving 7, 11, and 17-level three-phase MLIs. The results are verified using both simulation and experimental studies. The results showed substantial improvement and superiority compared to other available algorithms both in terms of the harmonics reduction of harmonics and finding the correct solutions.

The multilevel inverters (MLI) are resourceful in producing a voltage waveform with superior-quality staircase counterfeit sinusoidal and depressed harmonic distortion (THD). Several conventional topologies are proposed to realize the MLI however, the limitations of these topologies may involve more DC sources and power-switching devices, and less THD, which in turn, increases the cost and size of the inverter. These drawbacks can be eliminated with the proposed hybrid Cascaded H-Bridge Multilevel Inverter with reduced components topology. As compared with the established MLI topologies the recommended topology having a reduced number of DC sources, power-switching devices, component count level factor, lesser TSV, more efficient, lesser THD, and cost-effective. The proposed MLI is a blend of a single-phase T-Type inverter and an H-Bridge module made of sub switches. This article incorporates the design and simulation of the multilevel inverter with staircase PWM technique. Further, the 9-level and 17-level MLI is examined with different combinational loads. The proposed inverter is stable during nonlinear loads, and it is well suited for FACTS and renewable energy grid-connected applications. An operational guideline has been explained with correct figures and tables. The Output voltage wave is realized in numerical simulation. Finally, the experimental demonstrations were performed by implementing a hardware prototype setup for both linear and nonlinear loads using the dSPACE controller laboratory.

The Modular multilevel converters (MMCs) have excellent performance when operated with high modulation index such as the case of gird-connected converters in high voltage direct current (HVDC) system. Reliable and fault tolerant operation (FTO) of the system is very important in HVDC. A novel FTO algorithm under sub module failure without using any additional redundant SMs is proposed. In the proposed method, the direct current bus voltage control and on-load tap changer (OLTC) control strategy are combined for interruption free operation of the system without any additional voltage stress on switching devices and performance degradation of the system during fault. The analytical details of the normal as well as FTO operation are given. The proposed FTO strategy is verified through simulation and also experimentally using a prototype. The simulation and experimental results are presented.

An accurate iron loss estimation is necessary before manufacturing the filter inductors of the three-phase grid-connected converters. Besides the loss characteristics of the magnetic core, obtaining an accurate current flowing through the inductor is also very important in the iron loss estimation. In three-phase grid-connected converters, there are two current ripple periods with different magnitudes in one switching period, both of which can generate the iron loss in the converter. In this paper, a dual current-ripple envelopes (DCRE) method is proposed to accurately outline the two current ripples in each switching period. A novel iron loss estimation method is further presented based on the DCRE and the existing iron loss characteristics. Adopting the DCRE method, the influence of pulse width modulation (PWM) schemes, voltage levels, and the amplitude of output current, can be easily evaluated, which provides a satisfactory guidance to the design of the inductor. The effectiveness of the proposed DCRE and iron loss estimation method is verified by the numerical simulation and the experimental test on a three-phase grid-connected converter.