Pulse Width Modulation Control Research Articles

A New Generalised Symmetrical/Asymmetrical Boost Integrated Multilevel Inverter with Reduced Components for PV/UPS Applications

ABSTRACT This paper proposes a new generalised boost integrated multilevel inverter (MLI) with reduced components. The proposed MLI is developed by using a modified boost integrated switched capacitor unit, which provides four-level output from each cell. The operation of the proposed MLI for symmetrical 17-level operation with sinusoidal pulse width modulation & nearest level control and asymmetrical 31-level operation with NLC is explained and validated experimentally. The experimental results of static and dynamic load conditions are analysed and discussed in detail. In addition, the proposed topology is compared with recent boost MLI topologies in terms of component count, device stress, efficiency, capacitor size and cost. From the comparative study, it is evident that the proposed MLI provides features such as reduced component count, capacitors size, overall cost and improved voltage gain.

Development of contactless switching devices for asynchronous machines in order to save energy and resources

To limit the inrush currents in the stator windings, various schemes for starting an asynchronous electric motor are used. In addition, the existing devices have a complex control system, which creates certain difficulties in installation and operation. But the analysis of scientific literature and materials from certain sources testifies to the insufficient study of this problem. In scientific work, the advantages and disadvantages of a new type of contactless starter are compared with contact and non-contact starters of various types. An original circuit of a new type of thyristor starter with a simplified design has been developed and manufactured, which has the ability to smoothly start and control the power consumption of asynchronous machines. Computer simulation of a new type of contactless starter with pulse-width modulation control in the Matlab Simulink program has been carried out: a pulse current is supplied to the controlled thyristor electrode on the basis of the pulse-width modulation control and the thyristor opens and passes the current, the resistance is set to decrease the input signal level. The design of the proposed starter is based on the combination of a thyristor starter with logical control, which has the ability to smoothly start and remote control of the power consumption of asynchronous electric motors, which has the ability to save energy and resources. Modern methods of implementing a logical control system, a pulse current generator with RLC filters, are proposed, and the task of remote monitoring and control of power consumption of asynchronouselectricmotors is set.

A review on the closed-loop strategy for speed control of BLDC motors

The advancements in the field of materials and force gadgets, coupled with the increased affordability of highperformance processors, have led to a widespread adoption of Brushless Direct Current (BLDC) motors across various industries. These applications range from household appliances to automotive, aerospace, and medical sectors. The widespread use of may be attributed to its manifold advantages over various types of engines, such as its superior efficiency, robust power output, extended operational lifespan, relatively quiet operation, and broader range of achievable speeds. Due to the increasing adoption of Brushless Direct Current (BLDC) motors in many real-life applications as a replacement for traditional motors, this paper aims to compile and evaluate a comprehensive list of control algorithms employed for BLDC motor control. This study discusses several ways for managing speed and current, including hysteresis band control, variable DC-link voltage control, and Pulse Width Modulation (PWM) control schemes. The optimization of Proportional-Integral-Derivative (PID) gains for these controlling techniques is achieved through the utilization of the particle swarm optimization (PSO) algorithm. By employing Fast Fourier Transform (FFT) analysis to examine the controller behavior through frequency analysis of the output signals and calculating the Total Harmonic Distortion (THD), a more advantageous control method may be determined.

Neural Network-Based Optimisation of Sinusoidal PWM Controller for VSI-Driven BLDC Motor

Abstract Although increasing the number of switches increases the switch losses, most designed controllers focus on controlling an inverter circuit with more than six switches. The paper aims to address this issue that arises in implementation of the voltage source inverter (VSI) for brushless DC (BLDC) motors. It optimises the sinusoidal pulse width modulation (PWM) controller, minimising total harmonic distortion (THD) while keeping the VSI’s circuit at six switches to avoid increased switching losses. This was achieved by applying an artificial neural network (ANN) to generate a signal, which combines with the already existing reference and carrier signals. The addition of the new signal to the existing signals contributed to generating more pulses compared with the conventional sinusoidal PWM. Simulink was used to design the system and analyse its performance with the conventional and neutral point clamped (NPC) VSI systems. Results indicated that the proposed system performs better when controlled with an LCC filter. Compared with the control experiments, its output waveform has the lowest THD value, which is 6.04%. The switching losses of all the systems were also computed. Results from the computation indicated that the proposed system is capable of reducing the switching losses by 0.6 kW compared with the NPC VSI brushless DC motor (BLDCM) system. BLDCM speed was tested across various conditions; the results are reported in Section 5.

VSFPWM Based on Circulating Current Ripple Prediction for ZVS in Two Paralleled Grid-Tied Inverters With Coupled Inductors

Zero voltage switching (ZVS) control is an effective and promising way to further improve the power density, efficiency and electromagnetic interference for the two paralleled silicon carbide inverters with coupled inductors. In this article, focusing on the popular 180 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> interleaved pulsewidth modulation (PWM), the circulating current ripple prediction model is first derived as a function of operating conditions in the time-domain. With the assistance of this model, the actual trajectory of phase-leg currents can be reconstructed by superposition of sampling fundamental current and predicted circulating current ripple, without adding any high-frequency current sensor or auxiliary circuit. By carefully considering the ZVS requirement of all switches, a variable switching frequency PWM (VSFPWM) for full range ZVS control is proposed in this article. The proposed VSFPWM shows a good performance of ZVS realization in various load situations, as well as a good dynamic response of the inverter during current step change. In addition, due to the real-time variation of switching frequency, the proposed VSFPWM demonstrates the obvious advantage in conductive EMI reduction. Both the simulation and experimental results are presented to verify the effectiveness of the analysis and proposed method.

A Simplified DTC-SVPWM Scheme for Induction Motor Drives Using a Single PI Controller

Apart from variable switching frequency, a major issue in direct torque controlled (DTC) induction motor drives is the high torque ripple, which can be minimized by incorporating suitable pulsewidth modulation schemes such as space vector pulsewidth modulation (DTC-SVPWM) and duty ratio control DTC. However, the simplicity and robustness of the DTC scheme are compromised due to the high computational complexity and requirement of a number of motor parameters for the control. In this article, a simple and elegant control algorithm for the realisation of the DTC-SVPWM that is less dependent on motor parameters is proposed. The stator flux-linkage space vector angle needed to generate the reference torque for the DTC operation is computed based on the basic torque equation and the reference stator phase voltage needed for the SVPWM is determined in turn in every sampling period. For the modulation, a carrier-based space vector pulsewidth modulation (CSVPWM) scheme is adopted to get low torque ripple at constant switching frequency. The proposed speed control scheme avoids the use of rotor parameters and rotating reference frame transformations. It requires no sector identification and only one PI controller is needed for the speed control. Though the scheme has comparable torque ripple as that of the conventional DTC-SVPWM scheme, it significantly reduces the computational burden. Hardware results on a three-phase, 2 HP, 415 V induction motor are presented to validate the performance of the proposed control scheme.

Open problem: WTHD reduction understanding for a synchronous saw-tooth injection PWM control

Third harmonic injection pulse width modulation (PWM) is a well known inverter control method improving the harmonics quality. Nevertheless this field of research is not closed and recent researches showed that a wide spread of third harmonics injection inside the zero sequence component of a synchronous carrier based PWM improves the voltage harmonics at the output of a three phases two-level inverter.Furthermore, for some specific parameters, this new zero sequence component modulation (ZSCM) seems to converge to a saw-tooth shape. The presented research is the direct continuity of the previous paper on ZSCM [Bourgeade et al. (2021a)].The following work is attached to show a description and advantages of the saw-tooth injection PWM (STIPWM). As STIPWM is very singular in the literature, a mathematical understanding is judged necessary in order to find new PWM properties to stimulate power electronics control research.Then, this paper present to the community the STIPWM problem and an incomplete demonstration which leads to establish a conjecture, following a stimulating explanation will be found.

Decentralized space vector pulse width modulation method for multilevel single-phase half bridge converters

This study presents a space vector pulse width modulation (PWM) method for a multilevel single-phase decentralized power converter (DPC) called MSPDPC. The proposed model is built by connecting half-bridge cells in series. The output voltage can be adjusted according to demand by adding or subtracting cells. Cells use communication protocols to transmit and receive information with two neighboring cells. The received data contains information for the decentralized space vector pulse width modulation (DSVPWM) method proposed in this paper. In the proposed DSVPWM method, cells set up links to exchange information such as cell position, total cells in a phase, reference voltage amplitude, and reference frequency. The PWM control signals of each cell are calculated based on the information received. The study also focuses on evaluating the ability to adjust the switching vector and the corresponding dwell time of the cells when the structure of the DPC changes. The ability to dynamically reconfigure the DPC is a crucial feature that ensures uninterrupted power supply in case of one or several cell failures. The system automatically establishes a new state with the active cells. The proposed configuration and communication method between cells provide very fast configuration times. The load voltage of the DPC is adjusted to 0.5 times the voltage per cell, which allows the modulation voltage amplitude to be adjusted best according to the load requirements. The study used Matlab/Simulink software to review the initial assessments. The proposed model and algorithms will be verified on the Digital Signal Processor (DSP) platform with a 220V/500W load.

Nonisolated Dual-Output Single-Phase Boost Inverter With Reduced Active and Passive Components

This article proposes a nonisolated dual- output single-phase boost inverter with reduced active and passive components. The suggested inverter can serve two single-phase ac loads independently like two full-bridge inverters, but owing to the use of a pair of three-switch legs in the inverter bridge, it has a 25% reduction in active switches. The proposed inverter is capable of obtaining a boost output voltage while employing fewer passive components compared to the traditional impedance source inverter. And the high-frequency current commutation problem of diodes in the traditional split-source inverter is solved by replacing the diodes with two complimentary switches. A hybrid sinusoidal and constant pulsewidth modulation control strategy is elaborated, which enables the proposed inverter to operate in equal frequency mode and different frequency mode. Comprehensive working principles, modulation strategy, steady-state analysis, and parameter design guideline are introduced, both simulation and experimental results are presented to confirm the characteristics of the proposed topology.

Analysis of a self-sufficient photovoltaic system for a remote, off-grid community

Background A photovoltaic (PV) system, especially the stand-alone type, along with a battery storage system, plays a significant role in providing the needed electrical energy to remote, off-grid communities. Methods In this study, a stand-alone PV solar cell was enhanced to better understand the system operation. Modeling and simulation were performed using MATLAB software. Results This work has shown that the I-V (current-voltage) and P-V (power-voltage) characteristics of the modelled system have a profound effect on energy when a pulse width modulation controller is used as a charger. The modelled PV system generated the required energy under different conditions, considering temperature and PV battery voltage mismatches. Conclusion In summary, the simulated model in this study can be considered a system capable of detecting different conditions with the presence or absence of light at different temperatures. Finally, monitoring the temperatures, adjusting the voltage with a suitable charger controller, and selecting solar modules made of optimal materials can increase the efficiency of the solar system and allow it to be used in more applications.

Real-Time Frequency Stabilization of Standalone PV System with SMC

This paper aims to obtain suitable control for the Standalone Photo Voltaic (SAPV) system to meet consumer demands in weather conditions. A SAPV system is developed with a solar array with Maximum Power Point Tracking (MPPT), a Boost converter, and an inverter. This system uses controllers for maximum power output tracking, constant DC output of the Boost converter, and constant output voltage and frequency with Pulse Width Modulation (PWM) control mode. MPPT, boost converter, and inverter controller parameters are designed and tuned, respectively. Proportional gain (Kp) and Integral gain (Ki) values and the Sliding Mode Method (SMC) tune the controller parameters. The innovative aspect of this work is to propose a standalone PV system with controllers based only on the sliding mode control approach. Moreover, the current controller provides an output current of high quality with a THD of 1.6 %. Effectiveness and robustness of the proposed scheme modeled and simulated under OPAL-RT real-time Software in Loop (SIL) platform with MATLAB Simulink under fast variations of irradiance and temperature. Various analyses have been carried out for examining the proposed Sliding Mode Controller-based standalone photovoltaic system.

Three-phase Inverter with Fuzzy Logic Control (FLC) based Maximum Power Point Tracking (MPPT) technique for Grid Connected Photovoltaic (GCPV) System

The performance of the Photovoltaic (PV) System is dependent upon the environment conditions due to the variation of the solar irradiance and cell temperature. This affects the quality of the output voltage that is generated by the photovoltaic modules. To overcome these challenges, an artificial intelligence approach is implemented into the system. The objective of the proposed work is to develop a boost converter to control the output power generated by the photovoltaic modules by increasing the output power. In order to adjust power factor and power for a three-phase grid inverter system, the boost converter is integrated with a three-phase inverter that uses the Pulse Width Modulation (PWM) control approach. Since it's the most important component of any grid-connected system and enables the source generated to feed into the grid, it evolved to control power to the grid. Therefore, the three-phase inverter with PWM control is proposed to optimize the performance of the PV system. A Fuzzy Logic Control (FLC) is implemented in the system as an artificial intelligence alternative for a PV system that works rapidly, accurately, and efficiently to track the Maximum Power Point (MPP) under varying weather conditions and solar irradiation. By using the FLC, the constraints that come from conventional technologies could be improved and a better grid-connected photovoltaic system be provided. The proposed PV system is modelled and simulated in MATLAB/Simulink. The simulations results are presented.

A review on technological aspects of different PWM techniques and its comparison based on different performance parameters

AbstractUse of Pulse Width Modulation (PWM) techniques has enabled the converters to be used in low‐frequency high‐power applications. The main objectives of PWM are to reduce the line current harmonic, switching energy loss, and torque pulsation and motor acoustic noise (for motor drive applications). This paper mainly deals with selective harmonic elimination PWM (SHEPWM), Hysteresis current controlled PWM (HCPWM), space vector PWM (SVPWM), bus‐clamping PWM (BCPWM), and the most advanced wavelet PWM technique (WPWM). Different conventional as well as advanced soft computing techniques have been discussed for SHEPWM in order to solve the complex non‐linear transcendental equations and obtain the optimized switching angles. The paper also deals with different conventional and advanced bus clamping sequences that have shown superior result in mitigating the switching loss. In order to judge the true performance of SHEPWM and CSVPWM in terms of accuracy of obtaining the switching angles, convergence rate, THD, torque ripple, switching energy loss, etc., a common experimental test bench consisting of three‐phase, two‐level, six switch inverter coupled with a 2 hp, 50 Hz, three‐phase induction machine has been formed. The selected BIA‐based SHEPWM and CSVPWM have been implemented in the MATLAB simulation software, and the same has also been applied to the experimental test bench through dSPACE 1104 DAC card. Performance of HCPWM and different BC‐PWM sequences has also been verified using the same experimental test bench. This manuscript will help the researches and practitioners working in this field, to gain a clear idea about the type of PWM to be used for their specific application in order to achieve superior performance.

Control of Dynamic Performance Through Feedback Converter SSC In Grid Integrated Wind Energy System

A feedback converter-based Static series compensator (FBC-SSC) is a device that can simultaneously compensate for currents and voltages in a distribution network to enhance the Power Quality (PQ) in Grid integrated Energy System (GIWES). PQ is a term that refers to the conjunction of voltage and current stability. Electronically operated and non-linear gadgets with significant applicability in distribution networks and enterprises have become significant aspects due to PQ constraints such as imbalance voltage and frequency, and transients. Improved hysteresis-based FBC-SSC is suggested in this study for optimizing PQ in GIWES. The novelty in this research is improved hysteresis or hybrid PI and PWM-based hysteresis controlled FBC-SSC. In a wind turbine generation system, improved hysteresis based is used to find the gate trigger pulse for SSC. The suggested controller, when combined with FBC-SSC, improves the WES dynamic performance. Simultaneously, the grid network can compensate for current and voltage irregularities in nearby terminals. All converters in the proposed topology share a standard dc-link capacitor. As a result, power can be transmitted from one distributor to another. The proposed topology is modelled in the MATLAB/SIMULINK environment. The effectiveness research is performed using the improved hysteresis controller. Finally, the obtained results are compared to two existing controllers: a Proportional Integral controller and a traditional Pulse Width Modulation (PWM) controller. As a consequence, the performance level can show that the advised technique is effective. When compared to another typical control approach, the suggested system obtains remarkably low THD values of 0.94 percent.

Dual-Mode Control Scheme to Improve Light Load Efficiency for Dual Active Bridge DC-DC Converters Using Single-Phase-Shift Control

In vehicle-to-grid (V2G) applications, dual active bridge (DAB) converters are commonly used as the power interface because they offer high efficiency, galvanic isolation, and bidirectional power flow. For the DAB control strategy, phase-shift control is the mainstream, especially the single-phase-shift (SPS) method because of its ease of implementation. However, due to the phase shift, a DAB converter operated under this control method has relatively high backflow power, resulting in poor efficiency. The SPS control method has the drawback of high backflow power, especially at light loads. Thus, this paper proposes a new dual-mode control scheme to improve the light load efficiency of DAB converters by taking advantage of the pulse-width modulation (PWM) strategy in combination with the conventional SPS strategy for DAB converters based on load conditions. In other words, when the DAB converter operates under light load conditions, the PWM control strategy is used to avoid considerable backflow power. A prototype DAB converter with a power rating of 1 kW under a switching frequency of 100 kHz interfacing a DC bus (400 V) and a battery pack (50 V) is designed and implemented to verify the feasibility of this control strategy. A detailed analysis of the working principle and design parameters of the proposed converter is provided in this paper. Experimental results show that the highest efficiency of the proposed converter at light loads (10–200 W) was 96.2% for the forward power conversion and 97.3% for the backward power conversion.

A 12V/24V-to-1V PWM-Controlled DSD Converter With Delay-Insensitive and Dual-Phase Charging Techniques for Fast Transient Responses

A 12V/24V-to-1V pulsewidth modulation (PWM) controlled double step-down (DSD) power converter with delay-insensitive and dual-phase charging techniques is presented. The proposed PWM controller has two feedback loops to regulate the output voltage and the voltage across the flying capacitor, respectively. With the proposed delay-insensitive technique, near-optimal transient responses are achieved by using the PWM control regardless of the time of occurrence of the transient. Moreover, the responses are further improved by two times by using the proposed dual-phase charging technique. The converter was fabricated in a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> BCD process with all power transistors integrated on chip. For 12V-to-1V conversion and 24V-to-1V conversion, the measured peak efficiencies at 1-MHz switching frequency are 88.3% and 83.5%, respectively. With a load current step of 3 A and a rise time of 20 ns, the measured voltage droop and 1% settling time are 56 mV and 0.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> , respectively.

A Unified Control for PFC Converter With Seamless Transition Between PWM/PFM Modes

Discontinuous conduction mode is often used in boost power factor correction converter. This article proposes a unified control method to achieve both pulsewidth modulation control and pulse frequency modulation control, which is based on the virtual impedance principle. The control modes can easily be changed by only adjusting one control parameter. Consequently, by comprehensively considering current ripple, switching frequency, and efficiency, the converter can operate flexibly in the situation of variable loads. This article first introduces the operation principle of the proposed unified control method. Then, the operation condition for each control mode is discussed. Besides, the current ripple, the switching frequency, and the power loss are analyzed. Finally, the experimental results of steady-state test and load switching test are presented. And the efficiency of the converter is more than 95% in the range from half load to full load. These experimental results fully verify the effectiveness of the proposed control.

Digital Resonant Current Controller for LCL-Filtered Inverter Based on Modified Current Sampling and Delay Modeling

In this article, a digital resonant current controller is proposed for pulsewidth modulation (PWM) control of an LCL-filtered inverter based on a modified current sampling method and time delay modeling. Since the current sampling technique employed here uses a freely tunable sampling instant within the PWM signal period, a corresponding LCL filter model discretization technique is used based on a modified Z-transform. This is applied to model the fractional delay introduced by the current sampling technique, which uses sampling instants from within the PWM signal period. Modified Z-transform-based delay modeling has not previously been employed for LCL-filtered inverters, although it has been used in inverters with an RL load. The proposed technique is implemented with a fifth-order current controller, which directly controls the power converter ac output current without the need for active damping, as is typical for converters with LCL filters. A method based on pole placement is adopted to tune the controller parameters, in which the positions of all the closed-loop poles of the control system are determined. The responses of the controller to reference and disturbance signals are analyzed through simulation and experimental testing for different sampling instants within the PWM signal period.

A PWM Plus Phase-Shift Control for Four-Switch Buck-Boost Converter to Achieve ZVS in Full Input Voltage and Load Range

Four-switch buck-boost (FSBB) converter features positive output voltage and low voltage stress of power switches. In this article, a pulsewidth modulation plus phase-shift control scheme is proposed to achieve zero-voltage-switching for all the power switches in full input voltage and load range and minimize the inductor current ripple and root mean square (RMS) value. The implementation of the proposed control scheme is given. A prototype of a 500-W FSBB converter is built and tested in the lab, and the experimental results verify the effectiveness of the proposed control scheme.

A Dual-Branch Series-Parallel Hybrid Buck DC-DC Converter With Flying Capacitor Voltage Auto-Balancing

This paper presents a dual-branch series-parallel hybrid buck converter with flying capacitor voltage auto-balancing and reduced output impedance. The proposed converter automatically and inherently balances the flying capacitor voltages as one-third of the input voltage. Besides, the proposed converter operates in four states per cycle rather than the conventional six states, leading to a feasible Type-III compensation of the analog pulse-width modulation (PWM) controller. Moreover, due to the multiple parallel current paths in the switched-capacitor network, the proposed converter reduces the output impedance, thus decreasing the conduction loss. Finally, validated in 65-nm CMOS, the proposed converter regulates a 0.55 V–1 V output voltage from a 3.6 V input voltage over a large output power of 0.45 W with 82% peak efficiency, and switching frequency up to 5 MHz. It also automatically sets the flying capacitor voltages at 1.2 V.