Pulse Width Modulation Control Method Research Articles

Real-time of a two-level three-phase inverter controlled by PWM and full wave techniques

Sustainability in power generation is readily available and must be able to adapt to a variety of energy needs or integrate seamlessly into alternative distribution networks. This research aims to bridge the gap between continuous energy production and efficient energy utilization by advancing the understanding and application of three-phase dual-level voltage inverters. This study focuses on two main objectives: firstly, to develop a comprehensive model and secondly, to validate the functionality of a three-phase two-level voltage inverter. The control strategy employed for this inverter involves the full-wave method and pulse-width modulation (PWM). The results obtained from the hardware implementation of these control methods show impressive levels of success, closely matching the expected performance of the three-phase inverter. This success underlines the robustness and effectiveness of both full-wave and PWM control strategies. To further underline their practical applicability, experimental validation of PWM and Full Wave control methods is demonstrated in a controlled research laboratory environment.

Load sensitive control characteristics of a novel two-dimensional pulse width modulated variable mechanism

Load sensing technology is a typical hydraulic technology that automatically meets load requirements by adjusting the pressure and flow at the pump outlet. Traditional load sensitive pump control systems rely on variable mechanisms to achieve such flow control characteristics. However, general variable mechanisms have complex structures and poor dynamic performance if frequently adjusted. Therefore, a new variable mechanism, named two-dimensional pulse width modulation rotary valve, is proposed. Different from the pulse width modulation control method of the electronic technology, the two-dimensional pulse width modulation rotary valve conducts secondary distribution of the quantitative pump output in the way of fluid pulse width modulation: the valve core rotates to generate discrete fluid, and the axial sliding of the valve core controls the duty ratio of the discrete fluid. The dynamic balancing of the axial displacement is controlled by feedback pressure to provide a fixed differential pressure for the control valve, achieving that the flow through the control valve is uniquely controlled by the valve opening of the control valve. The principle of the fluid pulse width modulation is first introduced, and then the mathematical model of the proposed variable mechanism and the corresponding system is established. Simulation analysis is implemented. Finally, the effectiveness of the load sensing system controlled by a two-dimensional pulse width modulation rotary valve is verified by the experiment.

Study on combined optimization technology of wind-solar-storage hybrid power generation based on electricity hydrogen complementarity

The wind-solar-storage hybrid power generation system is mainly composed of wind turbines, solar cell arrays, electrolytic cells, fuel cells, battery packs, intelligent controllers, multi-functional inverters, cables, supports and auxiliary parts to supply power to the load. The system utilizes wind and solar energy for power generation without an external power supply, and an energy storage module composed of an electrolytic cell, fuel cell, and battery is used to assist the power supply. In this paper, a fuel cell model, a wind power generation model and a solar power generation model are respectively constructed, and a small experimental platform was built to validate the model. The pulse width modulation (PWM) control method, combined with the auxiliary regulation of the system by the battery, reduces the impact of the volatility of wind power generation on the electrolytic cell and fuel cell, and makes the load current more stable under different working conditions. The simulation results show that the system has good compression resistance, fast response and good stability.

Power flow analysis in a distributed network for a smart grid system

<span>This article presents the implementation of a hybrid renewable energy-based smart grid in a distributed system. Photovoltaic (PV) and wind generation are variable and time-dependent, yet they are very efficient and correlated, making them perfect for a two-source hybrid system. To maximize the generated power, using the maximum power point tracker (MPPT) technique, the incremental conductance (IC) algorithm is employed. The proportional integral (PI)-based MPPT controller is chosen to improve the efficiency of conventional MPPT controllers. A battery system is implemented as an energy management system (EMS) to aid in transferring or managing the high load throughout peak and off-peak hours. The proposed system uses an optimization technique called genetic algorithm (GA) to control the inverter voltage. The GA-tuned PI controller performs efficiently and has less harmonic distortion than the traditional sinusoidal pulse width modulation (SPWM) control method. The designed system uses real-time measurable parameters as inputs and is simulated in Matlabtool. The system generates 42 kW of solar power and 250 kW of wind power; the total harmonic distortion (THD) value is 5% less than the SPWM technique. For future work, flexible alternating current transmission system (FACTS) devices can improve the power quality and lower the oscillations.</span>

A Nine-Level Inverter with Adjustable Turn-Off Time for Helicopter Transient Electromagnetic Detection.

The current inverter is the core component of the helicopter transient electromagnetic (HTEM) detection system. It should meet the concerns of low loss, high power, and fast turn-OFF time. This article proposes a new circuit topology based on nine-level inverter technology to overcome the drawbacks of typical PWM (pulse width modulation) inverters, such as switching losses and harmonics. This circuit topology overcomes the shortcomings of the traditional single constant voltage clamp circuit in which the turn-OFF time is not adjustable. Using an inverter with the proposed topology is able to avoid the complex PWM control method and switching loss. In this way, the current rising edge and falling edge of this inverter are also improved effectively. The proposed inverter has adjustable turn-ON-time and turn-OFF time, which is significantly different from the conventional single-clamp inverter. Through subsequent experiments, the inverter proved to have the capability of generating trapezoidal current waveforms. Moreover, by modifying the FPGA (Field Programmable Gate Array) control program, three different turn-OFF times are achieved. The nine-level inverter has a peak current of 1.5 A with an adjustable turn-OFF time from 129 μs to 162 μs. Moreover, the switching frequency of the inverter is reduced from 10 kHz to below 100 Hz. The experimental results further demonstrate that it achieves lower switching losses and more flexible transmission. Our work in this article provides an efficient way to improve the performance of HTEM detection systems.

Control of Free Piston Stirling Linear Generator system connected with dc/dc converter for energy storage applications based on SVPWM Rectification Method

Recently, the world has been facing several challenges in terms of environmental change, which is expected to increase in the coming periods. Further challenging is how to reduce the emissions of greenhouse gasses into the atmosphere. Such emissions pollute our atmosphere, resulting in global warming. However, the wide use of renewable energies can both help to fight against this phenomenon and reach long-term goals. Considering the growing global concern over the use of fossil fuels and environmental pollution. In this case, a Stirling engine with diversified heat sources and low pollution was developed, and the Free Piston Stirling Linear Generator (FPSLG), which can be directly connected to the Stirling engine and thus eliminate the need for an intermediate mechanical transmission mechanism, was used to create a power generation system with the Stirling engine and has been employed in a range of applications, including space power supply, solar energy generation, and others. This article models two sets of power converters, one of which is connected to the FPSLG and the other to the storage battery system. The Space Vector Pulse Width Modulation (SVPWM) control methods adaption to the AC/DC rectifier and the two-loop Proportional Integral (PI) control method adaption to the DC/DC converter used for renewable energy conversion is proposed. Furthermore, the traditional PI in the position loop is replaced by a Proportional Resonance (PR) controller to increase the frequency and displacement tracking performance. The linear generator’s control system is simulated, and the efficiency of the proposed control strategy is proven. The system was initially simulated in MATLAB/Simulink using the dq-PI current controller to produce the logic pattern for the Voltage Source Rectifier (VSR), and the resulting logic pattern was examined.

Double duty ratio PWM control method for a novel HSV actuator with low power consumption

This paper presents a novel high speed valve (HSV) actuator with low power consumption. The structure design of tapered armature and control method of double duty ratio pulse width modulation (PWM) are proposed in the HSV actuator to improve steady and transient characteristics. The electric-magneto-mechanical model of the HSV actuator is established and investigated by theoretical analysis. Parameters improvement of the HSV actuator is analyzed by the model, and optimized results for a prototype actuator have been obtained. The experimental and simulation curves agree well with the changing trend, and show that the opening time of the HSV actuator is 7.3 ms, the closing time is 20 ms, and power consumption in maintenance stage is 1.35 W, within the stroke of 2.5 mm. Compared with normal driving method, the proposed structure and method have the advantages of opening time reduced by 37%, closing time reduced by 29%, and steady-state power consumption reduced by 93.5%. The proposed structure and method in the HSV actuator are available to meet the driving requirements of both steady and transient performance in fluid control systems better, especially in power shortage or power supply inconvenient engineering.

Research of control method for pneumatic control of pneumatic microchips.

A novel composite control method for actuated chamber air pressure of pneumatic microfluidic chip via a three-way electromagnetic microvalve is presented in this paper. The purpose of the control methods is to improve air pressure controlling precision for pneumatic control. By using the Bang-Bang (on-off) controller for pneumatic control, the step-response time, air pressure steady-state accuracy, and air pressure fluctuations are performed with different maximum thresholds and minimum thresholds. Moreover, by using the k (proportional) plus PWM (Pulse-Width Modulation) control method for pneumatic control, the step-response time, air pressure steady-state accuracy, and air pressure fluctuations are performed with different carrier frequencies and carrier amplitudes. Both advantages and disadvantages of the two control methods are compared and analyzed based on the experimental data. According to the variable volume of the actuated chamber and the response characteristics of the three-way electromagnetic microvalve, the composite control method of the Bang-Bang plus k plus PWM is developed to control the actuated chamber air pressure. The experimental results show that when the absolute air pressure of the actuated chamber is set to 150kPa, the rising time is 69.3ms, which is about 8.0ms shorter than that of the k+PWM control method alone. The steady-state error is reduced from 0.90kPa to 0.65kPa, and the air pressure steady-state fluctuation is reduced from 1.60kPa to 0.90kPa, compared with the Bang-Bang control method alone.

Control strategy of MW flywheel energy storage system based on a six-phase permanent magnet synchronous motor

The implementation of the “dual carbon” goal, nationally in China, has accelerated the profound transformation of the energy industry, and the development and utilization of large-scale clean energy has become a basic global consensus. However, clean energy is having trouble meeting the needs of rigid energy demands due to its randomness, intermittency, and unpredictability, so energy storage is currently being considered to solve this incompatibility. The flywheel energy storage system (FESS) cooperates with clean energy power generation to form “new energy + energy storage”, which will occupy an important position among new energy storage methods. This study analyzes the basic requirements of wind power frequency modulation, establishes the basic model of the flywheel energy storage system, adopts a six-phase permanent magnet synchronous motor as the system driver, designs an eleven-stage pulse width modulation control method, and proposes a power and current double-closed loop. The control strategy is used to test and simulate the machine-side converter that has been built. The results show that the proposed control strategy is reasonable and effective. By introducing a six-phase permanent magnet synchronous motor into FESS, the system could output higher power under the condition of low voltage and the noise and vibration of the motor are optimized during operation. Most importantly, the stability of the FESS is guaranteed in actual operation.

Synchronous PWM Control With Carrier Wave Phase Shifts for Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors (PMSMs) are utilized in a wide range of applications as high-power-density and highly efficient drive sources. However, a PMSM generates electromagnetic vibration and loss caused by space and time harmonics. In this article, we propose a synchronous pulsewidth modulation control method for shifting the carrier wave phase against the modulation wave phase. As the proposed control matches the vibration frequencies caused by space and time harmonics, the pulsation caused by the space harmonics is canceled out by the pulsation caused by the time harmonics with the phase shift of the carrier wave. Experiments on the proposed control demonstrate that vibration at a specific frequency was reduced by 46% at 7900 rev/min. In addition, to change the carrier phase with small <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis current harmonics, magnet eddy-current loss was reduced by shifting the carrier wave phase. The temperature of a magnet was measured in a heat-run test, and the temperature rise of the magnet could be suppressed by 5 K.

A mode‐reduction space vector pulse width modulation control method to VIENNA rectifier yet eliminating input current distortions

AbstractThe VIENNA rectifier is of high reliability, high power density, and low complexity, which has been widely applied in telecommunication systems. However, it has 25 switching states complicating the control design. Besides, it is easy for the VIENNA rectifier to distort the input currents at zero‐crossing points, which will degrade the grid power quality. To address these problems, a novel mode‐reduction space vector pulse width modulation (SVPWM) control method is proposed in this paper. By analyzing the switching states of the VIENNA rectifier, 3‐mode, 6‐mode, and 18‐mode control framework are compared, and it is found that the 18‐mode has advanced features. Specifically, the proposed 18‐mode control algorithm will have fewer calculation steps and a simpler processing flow. More importantly, it can eliminate the input current distortions for power quality improvement. A 4 kW hardware prototype of the VIENNA rectifier is developed, and experiments have been performed to verify the harmonic reduction feature of the proposed 18‐mode control.

Three‐phase transformerless photovoltaic inverter without common mode leakage current

Since three-phase transformerless (TPT) PV inverters have large common mode leakage current (CMLC), a TPT PV inverter without CMLC is proposed. The proposed inverter is derived from three single-phase half-bridge inverters and a boost converter. Grounds of the PV array and three-phase loads are connected directly, so no CMLC exists in the TPT solar inverter. Operating principle, stability analysis, and loss calculation and example of the proposed three-phase inverter are illustrated in detail. The pulse-width modulation (PWM) and sinusoidal PWM control methods are used in the boost converter and three-phase inverter, respectively. The proposed inverter is a stable system. Finally, simulation and experimental results of a 900-W TPT PV inverter confirm the theoretical analysis. The CMLC in the proposed inverter is only about 0.8 mA, which is mainly caused by the ground line inductance and oscilloscope probe noise.

Variable Switching Frequency Control-Based Six-Step Operation Method of a Traction Inverter for Driving an Interior Permanent Magnet Synchronous Motor for a Railroad Car

Most railroad cars employ a natural ventilation cooling method. For this reason, severe problems occur in the control devices for the railroad cars due to the heat generated by the high-power switching loss. Therefore, the traction inverter for the railroad car requires a control method that can reduce the switching loss. In this paper, we propose a control method for an interior permanent magnet synchronous motor in consideration of the driving conditions of the railroad cars. The proposed method combines a variable switching frequency-based synchronous pulse width modulation control method, a flux-weakening control method that considers the maximum voltage modulation index, and an optimized over-modulation method. Through the proposed method, the utilization rate of the DC-link voltage can be maximized while lowering the switching frequency of the traction inverter as much as possible, and the high-performance current control can be performed in the entire speed region of the railroad car. The validity and effectiveness of the proposed method are verified by the simulation results and the experimental results.

A novel pulse width modulation for metal radiant panels to control the condensation risk in a hot and humid environment

A novel pulse width modulation (PWM) control method with surface condensation-evaporation cycle was proposed for metal radiant panels to control the condensation risk in hot and humid environments. Through an on-off solenoid valve, a whole cycle of the PWM consists of a fixed on-period duration, i.e., 20 min and an adjustable off-period duration in order to guarantee the formed condensate water on the panel during the on period evaporated completely at the end of the off period. A numerical heat transfer model of the radiant panel validated by experiment was utilized to evaluate the dynamic thermal performance of the PWM. According to the simulation results, the maximum accumulated condensation mass in the whole cycle was far smaller than the falling criteria of condensate droplets, revealing the ability of the PWM in eliminating the negative effects of surface condensation on the indoor environment. Furthermore, compared with the variable temperature control method with a supply water temperature equal to the dew point temperature, the radiant panel utilizing the PWM provided a 10% higher cooling capacity. The radiant metal panels using the PWM has an application prospect for retrofit buildings with low airtightness of the envelope in hot and humid regions by a significant reduction of condensation risks.

A DCM High-Frequency High-Step-Up SEPIC-Based Converter With Extended ZVS Range

A discontinuous conduction mode (DCM) high-frequency high-step-up single ended primary inductor converter (SEPIC)-based converter with extended zero voltage switching (ZVS) range is presented in this article. With the incorporation of some components on conventional SEPIC, the proposed converter achieves better performances such as high voltage gain, low voltage stress, and ZVS. The additional components form a resonant cell which enables the switches to work in ZVS, and switching loss is reduced accordingly. In order to achieve ZVS, the converter is designed to work in DCM. Due to inclusion of the resonance stage, traditional pulse width modulation (PWM) or pulse frequency modulation (PFM) control method is unable to regulate the output characteristics and maintain ZVS of the power switches at the same time. Therefore, a hybrid control method is proposed in this article to guarantee ZVS within a specific load range. According to this hybrid control method, the ZVS range is extended effectively. GaN switches and planar magnetic components are also used. Working principles and steady-state analysis are presented in detail. A 1-MHz 36-W prototype with 10 voltage gain has been designed to demonstrate theoretical analysis. Efficiency obtained is up to 91.8% at full load. Experimental results show good agreement with theoretical analysis.

Vibration noise suppression approach based on random switching frequency control for permanent magnet motor

The vibration noise of the distributed drive autonomous ground vehicle (AGV) is mainly produced by the inverter-fed brushless DC permanent magnet in-wheel motor (PMIWM). It is necessary to reduce the vibration noise level of the PMIWM driven by pulse width modulation (PWM). A suppression approach of electromagnetic vibration noise for the PMIWM is investigated. First, the air gap magnetic field of the inverter-fed PMIWM was analyzed. The electric current harmonics and the unbalanced magnetic force (UMF) were investigated. The natural frequency and noise of the PMIWM were presented. Then, a flux-weaken approach was employed to maintain the robustness of the PMIWM when a sudden drop of DC bus voltage. The random switching frequency (RSF) PWM control method based on a two-state Markov chain is proposed to decrease the amplitude of the harmonics caused by the switching frequency and the multiple switching frequencies. The experimental results show that the RSFPWM can not only effectively reduce the vibration noise and the inverter losses, but also improve the robustness of the PMIWM control system under unpredictable uncertainties.

Expansion of Operating Speed Range of High-Speed BLDC Motor Using Hybrid PWM Switching Method Considering Dead Time

In vehicle electrical systems with limited battery power, the output torque and speed of high-speed brushless DC (BLDC) motors can decrease due to unstable and reduced supply voltage or manufacturing errors in the motor back electromotive force (EMF). This paper presents a method that can guarantee the output performance of an inverter through a control algorithm without a separate power supply system and DC-link voltage increase. The proposed control algorithm can increase the output torque and speed of a high-speed BLDC motor by using appropriate selection and change of the inverter’s pulse width modulation (PWM) control method. In this paper, the operation and electrical characteristics of various PWM methods of BLDC motors are analyzed, and the optimal PWM method for improving the control performance of high-speed BLDC motors is presented. In addition, the relationship between the switching frequency, dead time, and voltage utilization was mathematically analyzed. Based on the results of this analysis, the proposed control algorithm automatically changes the PWM switching mode at the point where the output torque and speed need to be extended. The effectiveness and feasibility of the control method proposed in this paper is verified through the experimental results on the designed and manufactured high-speed BLDC motor system for vehicles.

Performance Improvement of PWM Control Methods for Voltage Step-Down in Series Resonant DC–DC Converters

The paper is focused on galvanically isolated series resonant DC–DC converters (SRCs) with a low quality factor of the resonant tank. These converters provide input voltage regulation at fixed switching frequency and good power density. Different modulation methods at the fixed switching frequency enable the implementation of the voltage buck functionality in these converters. The SRC under study is considered as a step-up front-end DC–DC converter for the integration of renewable energy sources in DC microgrids. The paper evaluates the voltage buck performance of the SRC achieved by using different pulse-width modulation (PWM) methods including conventional PWM and shifted PWM. Moreover, the new PWM methods, i.e., the hybrid shifted PWM (HSPWM), improved shifted PWM (ISPWM), and hybrid PWM (HPWM), are proposed to overcome the disadvantages of the existing methods. They improve the power conversion efficiency in the buck mode by reducing the power losses in the semiconductor switches and the isolating transformer of the SRC. The proposed and the existing methods are benchmarked in terms of the components stresses and power conversion efficiency. The presented findings have been experimentally validated by the help of a 200 W prototype, which demonstrated the lowest power loss in the case of the HPWM.

Nonconventional Diode Clamped Multilevel Inverter with Reduced Number of Switches

The conventional multilevel inverter (MLI) is divided into three types: diode clamped MLI, cascade H Bridge MLI and flying capacitor MLI. The main disadvantage of these types is the higher required number of components when the number of the levels increases and this results in more switching losses, system higher cost, more complex of control circuit as well as less accuracy. The work in this paper proposes two topologies of nonconventional diode clamping MLI three phase nine levels and eleven levels. The first proposed topology has ten switches and six diodes per phase while the second topology has nine switches and four diodes per phase. The pulse width modulation (PWM) control method is used as a control to gate switches. THD of the two proposed topologies are analyzed and calculated according different values of Modulation index (where the power loss and efficiency are obtained and plotted.

Hybrid-PWM-Controlled Current-Fed Bidirectional Series Resonant Converter With Low Current Ripple and Wide Voltage Gain

A hybrid pulse width modulation (PWM) control method for the current-fed bidirectional series resonant dc/dc converter (CF-SR BDC) is proposed in this article. In this proposed hybrid PWM control, the switching frequency is fixed to be the resonant frequency to facilitate the optimized design of magnetic components. In addition, the duty cycles of both high-voltage-side and low-voltage-side switches are also, respectively, regulated for different voltage gains. Based on this method, the CF-SR BDC is characterized by wide voltage gain, low current ripple, and high efficiency, as well as achieving soft switching for all the switches over a wide range of load. The operating principles, control method, and circuit characteristics are expounded specifically. A 160-240-V input and 400-V/1-kW output prototype was built in the laboratory, and the experimental results verify the feasibility of theoretical analysis.