PWM Control Method Research Articles

Design of dual-quadrant power supply based on bidirectional full-bridge transformation technology

Abstract Dual-quadrant programmable power supply is a bidirectional programmable DC power supply that integrates the functional characteristics of power supply and feedback load. This article adopts an automatic hybrid control method based on bidirectional energy flow, which adopts a phase-shifting control method and PWM control method respectively to achieve bidirectional control of power conversion.

Robust PWM control scheme for switched-capacitor MLI with leakage current suppression in grid-connected renewable energy application

Typically, parasitic capacitances exist between the ground and the solar panel terminals in grid-connected PV systems. These parasitic capacitances provide a path for a leakage current, which leads to significant safety concerns, observable and seriously hazardous harmonic orders aligned with the injected grid current, and significant safety difficulties. In this research, a robust PWM controlling method that used competently in reducing the level of the leakage current and improving the power quality of a switched-capacitor Multilevel Inverter. This technique creates developed reference signals from the main signal to generate the switching scheme for the converter circuit. Additionally, the suggested control strategy only works with a small number of carrier signals, resulting in a quick system response and a simpler controller algorithm. Likewise, this controlling approach offers a stable way to maintain a constant output voltage in the suggested converter by adjusting the switching capacitors' voltages, which is not possible with traditional control techniques. MATLAB/Simulink is used to simulate the outcomes for both the suggested control approach and the traditional Phase Disposition (PD) PWM control method whereas the leakage current component reduces to 25 % compared to the captured component with the PDPWM. The simulation and the practical results based on the dSPACE-1103 hardware are quite similar.

Isolation‐based bidirectional generalized step‐up multilevel converter with optimized device count

SummaryThis article describes a generalized single‐phase multiwinding step‐up transformer‐based multilevel converter with optimized device count. The proposed topology comprises of a single dc source, eight switches (four unidirectional and four bidirectional) and a single high‐frequency multiwinding transformer. Phase disposition pulse width modulation (PDPWM) is used for the level creation. The proposed converter is examined qualitatively and quantitatively using the total number of transformers, PWM control method, switch count, voltage stress, and the number of gate drivers, all of which are favorable. All elements of transformer selection, winding requirements, and comparative study have been thoroughly examined. A thorough Lagrange multiplier method has been applied to minimize the copper losses and optimize the multiwinding transformer (MWT) winding. The proposed converter simulations are performed using the MATLAB/SIMULINK environment. Further, the validation of the result is confirmed by a hardware setup of 0.9 kW.

Experimental Comparison of Carrier and Space Vector PWM Control Methods for Three-Phase NPC Converters

Multilevel converters are powerful converters in the medium-voltage high-power range. Inside this family of converters, the three-level neutral point clamped converter has its own importance. The main control methods associated with this converter are the carrier-based PWM with added DC components and the space vector PWM. Two of the most important features of the NPC converter are the neutral point balance and the output voltage spectrum. Both control methods efficiently manage the two characteristics. This paper experimentally compares these two issues and shows that the two methods produce almost the same results; the choice between one and the other should be made according to other requirements.

A Single-Stage Bimodal Transformerless Inverter with Common-Ground and Buck-Boost Features

This paper proposes a single-phase, single-stage common-ground inverter with a non-electrolytic capacitor and buck-boost ability. The proposed single-stage inverter is employed by a boost stage DC-DC converter and bimodal circuit, which makes it satisfactory for PV systems with a wide input voltage range and lower switch voltage stress. The leakage current of the proposed single-stage inverter can effectively suppress because the parasitic capacitor between the PV panel and the ground is shortened. In addition, the proposed single-stage inverter does not include electrolytic capacitors, which reduces the equivalent series resistance of electrolytic capacitors and also the size of the inverter system. The topology, operating principle, and PWM control method of the proposed single-stage inverter are given. The design guidelines of components and comparative studies of the proposed single-stage inverter are provided. A 500 W laboratory prototype of the proposed single-stage inverter is built to verify the correctness of the simulation and theoretical analysis.

Research on pneumatic servo brake technology using solenoid valve

The aircraft brake system plays a key role in the take-off, taxiing, and landing of the aircraft, and is a key system that affects flight safety. Both Hydraulic brake system and electric brake system have their advantages and disadvantages. The problem with the hydraulic brake system is the use of the power provided by the hydraulic system, and the distance from the pressure supply system to the wheel of the aircraft is far, which requires a long hydraulic line and increases the weight of the system, and there is also the risk of oil leakage. The electric brake system also has some problems - the jamming of the brake actuator may lead to a flat tire, and the weight is heavier than the hydraulic brake system, etc. However, for brake systems that require simple structure, low weight, and not short braking distance, pneumatic servo brake systems have unique advantages. This paper proposes a fast-switching pneumatic servo-brake system, by using solenoid valves to control air intake and exhaust and adding the segmentation control method and asynchronous PWM control method to the classical PID control method to achieve a pneumatic servo-brake. The pneumatic servo brake technology can ensure the responsiveness and accuracy of the brake system through a verification test.

A Novel Single-Phase Shunt Active Power Filter with a Cost Function Based Model Predictive Current Control Technique

For a single-phase Shunt Active Power Filter (SAPF) with a two-step prediction, this research presents a modified current control based on a Model Predictive Current Control (MPCC) technique. An H-bridge inverter, a DC link capacitor, and a filter inductor comprise the single-phase SAPF topology. The SAPF reference current is computed using the DC-link capacitor voltage regulation-based PI control technique. The weighting factor-based model predictive current controller is used to track the current commands. The essential dynamic index for evaluating waveform quality is the Total Harmonic Distortion (THD) of a source current and switching frequency of power switches. The conventional methods the THD and switching frequency are not considered as an objective function, so that a weighting factor-based MPCC technique is used to obtain a good compromise between the THD of the source current and switching frequency of power switches. Through MATLAB simulation and experimentation with the Cyclone-IV EP4CE30F484 FPGA board, the usefulness of the proposed control technique is proven. As compared with hysteresis, predictive PWM, and conventional MPCC control methods, the cost function-based MPCC algorithm provides a lower switching frequency (13.4 kHz) with an optimal source current THD value.

A new type of microgrid power quality improvement strategy based on harmonic suppression

Current harmonics and distorted voltage are two important factors that affect the power quality of microgrids. Combining with the operating characteristics of microgrids, this article uses a new strategy to control grid-connected inverters and UPQC to improve grid quality. Pointed out its advantages relative to traditional active filters, and in view of the current harmonic detection problems, In this paper, the inverter adopts an improved ip-iq harmonic detection method to improve the accuracy of harmonic current detection and has strong interference. The UPQC structure uses SVPWM and PWM control methods as its new control strategies on the series side and parallel side to compensate for distortion voltage and harmonic current. A detailed model is built in MATLAB/Simulink to verify the feasibility of this method.

THD optimization in 15-level asymmetric reduced switch count multilevel PV inverter using optimization algorithms

Philosophers and industries have focused on designing multilevel inverters, which use significantly fewer power switches and dc sources to achieve high power, low switching, and less harmonic output distortion for medium voltage applications. Even so, these multilevel inverters have some downsides like the use of many electronic components, electromagnetic interference (EMI), bulky driver circuit complexity, significant reverse recovery times, and voltage balancing issues. A modern asymmetrical multilevel inverter with fewer switches and drivers than standard topology is introduced in this article. The powerful analogy addresses traditional inverter topologies of a similar structure. The proposed MLI is relatively simple and easy to extend for many output levels. The proposed design of MLI is implemented for 15 level output with precise and high-quality near sinusoidal waveform using seven switches, three dc sources and three diodes and hence the volume, cost and driver circuit complexity is considerably reduced. The novelty in the proposed topology is that reduced ON state semiconductor switching devices. The output of the MLI is evaluated with the parameter of total harmonic distortion (THD). To minimize the THD, optimization algorithms such as GA, PSO, WOA and HHA were implemented at fundamental switching PWM control method. The comparative analysis of these algorithms on proposed inverter performance is integral for this research. The efficacy of this topology enhances the integration of renewable energy sources.

Quasi-Z-Source Inverters in Renewable Power Systems Modeling

This paper is devoted to in-detail demonstrationand description of the overall functionality and deailed processes in every component of quasi-z-source voltage inverter. Expressions for currents and voltages on all elements of the circuit in standard and "shoot-trough" modes are provided. These ratios demonstrate one of the main technological advantages of the quasi-z-source topology: which is the possibility of the voltage reduction on one of the capacitor that forms the quasi-z-circuitry that led to the overall size and weight reduction of the resulting device and additional reliability increase. Matlab calculations,that are provided in the practical part of the article,fully confirmed the theoretical dependencies. At the same time, obtained practical results of the simulation demonstrated the main advantage of the quasi-impedance topology - the ability to provide a continuous current of the input source without zero pauses. That is additionally confirmed by a graphical representation of transients and the spectrum of the output voltage of the inverter. As the second topic of the article, the problem of the control system operating principle selection was discussed. As it was determined in the process of the previous research and practical modeling of the quasi-z-source inverter, providing a switching of the inverter valves on the frequency that equal to the frequency of the desired output voltage, which for the most of the world’s electrical power systems is equal to 50-60 Hz, is leading to a size and mass increase of the quasi-z-source circuitry, according to its design ratios. Additionally, such component are either not represented in the modern electronic components lineup or providing sufficient energy losses that in some design cases could neglect the voltage boost effect of the quasi-z-source circuitry implementation. To overcome discovered limitations, several PWM control methods were suggested. All of them could be divided into two groups: classic and vector PWM methods. Classic methods are based on combination of the basic PWM modulation techniques that are widely used in conventional full-bridge invertors with the insertion of the “shoot-trough” state activation mode. A model of the control system for the classical approach is offered. It is shown that the method of simple control of the state of "breakdown" is based on the placement of time intervals of the inverter in the state of "breakdown" within the normal period of operation of the bridge inverter. The only difference between the models is the inclusion of an additional constant signal exceeding the amplitude of which the carrier leads to the activation of the “shoot-trough” state.In conclusion the discussion on topic of the classic control methods implementation in up-to-date designs and possibility of its combination with a different modern approaches aimed on a quasi-z-source topology parameters modification are provided.

Smart Bird Cage Based on STM32 for Turtledove Bird Using Solar Panel

Background: One type of bird that is widely bred and maintained is the turtledove. At turtledove breeding, bird cage maintenance is still done manually for cage lighting, feeding and drinking. Manual maintenance of the cage will make it difficult for farmers who have a fairly busy schedule or often leave the house.
 Aim: For that reason, the authors decided to make a Smart Bird Cage.
 Method: In this study, the authors used STM32F4 Discovery and ESP8266 as control centers via smartphones. The sensors that will be used are the temperature sensor and the Light Dependent Sensor (LDR). The outputs are 5 volt dc motor, 5V dc pump motor, buzzer and exhaust fan using on/off control with internet of things (IoT). While the control system for heating the cage uses the PWM control method on the AC module control for the brightness level of incandescent lamps.
 Findings: The results of this study are the temperature in the bird cage is controlled with a heating lamp that turns on when the temperature is below 30 oC and with the IoT system used by farmers, they do not have to worry about managing bird cage consumption when outside the city.

Design and Implementation of Multilevel Inverter with Various MPPT Algorithms for Optimal Tracking of PV System

In this paper the different algorithm is performed in MATLAB Simulink to extract large amounts of energy from the pv system. MPPT algorithm is used to reduce complexity and to get better results, we used to perturb and observation, incremental conductance and fuzzy logic algorithm. A three-phase NPC inverter is used to connect the PV array with grid system, The PWM control method is used for the producing the PWM inverter signals. it contains PV array, dc / dc boost, three level NPC inverter. To get the synchronization between PV system and grid the synchronous reference frame theory with PLL block is used. The SRF theory will transform the three phase load currents (ia, ib, ic) to the two instantaneous active (id) and reactive (iq) components. The MATLAB simulation is preformed and we get a constant high output voltage from low input voltage and by changing the irradiance and temperature.

A Single Stage 1 Switched Capacitor 7S-7L using Different PWM Topologies for Harmonics Reduction

Design and analysis of single-stage 1 Switched Capacitor (SC) boost 7Switch 7-Level (7S-7L) inverter for attaining higher voltage levels with reduced switches count using various PWM techniques is presented. PD, POD, APOD, VF, and CO is different PWM techniques which used to control the switches in the SC circuit. The main objective of this analysis is to reduce the existing drawbacks as increased switches count, high % of Total Harmonic Distortion (THD), and typical PWM control method. Single-stage SC-based boost converter topology in Multi-Level Inverter (MLI) that resolves the existing problem. Single source, two capacitors, and the voltage gain ratio of 4 are attained from the presented topology without the transformer. Furthermore, comparisons are made between the existing parameters such as THD value, voltage levels, and proposed THD, voltage levels with different PWM techniques. SC-based 7L inverter is implemented, in order to compare the performance of proposed better than the existing 5-level MLI and 5-level SC-MLI inverter, and THD is compared with various PWM techniques and 0.9 modulation index. The performance of the proposed method is validated through the simulation results using MATLAB/Simulink.

Investigation on adaptive pulse width modulation control for high speed on/off valve

High speed on/off valves (HSV) have often been used to control flow or pressure in digital hydraulic systems due to higher switching frequency. However, the dynamic performance and energy efficiency are highly affected by the supply pressure and the carrier frequency. In this paper, a new adaptive PWM control method for HSV based on software is proposed. The proposed adaptive PWM consists of a reference PWM, an excitation PWM, a high frequency PWM, and a reverse PWM. First, the nonlinear model of the HSV was established, and the structural composition and working principle of the proposed adaptive PWM control strategy were presented. Secondly, individual feedback controllers for the excitation PWM, the high frequency PWM, and the reverse PWM were designed, respectively; and each of the individual feedback controllers was experimentally verified. Finally, the comparative experimental results demonstrated that, with the proposed adaptive PWM control, the rising delay time of the control pressure drastically reduces by 84.6 % (from 13 ms to 2 ms), the duty cycle's effective range remains large (12 %-85 %) even with high carrier frequency (100 Hz), and the temperature rise of the valve's coil shell is reduced by 61.5 %, compared to the three-voltage control. In addition, the dynamic performance and the energy efficiency of the HSV are not affected by the supply pressures and carrier frequencies, which proves that the proposed control strategy can improve the robustness and stability of the valve system.

Bidirectional Simultaneous Wireless Information and Power Transfer via Sharing Inductive Link and Single Switch in the Secondary Side

In wireless power transfer (WPT) system, communication between the primary and the secondary plays an important role in system status monitoring and operation control. Bidirectional information transmission is also essential to detect the working state and send control command in both sides. This article proposes a bidirectional simultaneous wireless information and power transfer method. The secondary has a simple structure and employs only one switch. The proposed WPT system can achieve bidirectional information transmission via a sharing inductive link. The forward information is transferred by using a single full bridge inverter based on selected harmonic elimination PWM (SHEPWM) control methods without other high-frequency signal sources. In the secondary side, uncontrolled rectifier and a parallel MOSFET are adopted to realize constant voltage output and backward information transfer. The backward information modulation is achieved by changing the switching frequency of MOSFET. The forward and backward information demodulation modules are designed and analyzed in details. A 30W experiment platform with forward communication rate 5 kbps and backward communication rate 10 kbps is built to verify this proposed method.

PWM control method to eliminate Common Mode Voltage in three level T-Type inverters

In this paper, Common-mode voltage (CMV) is responsible for overvoltage stress to the winding insulation and bearing damage of an AC motor. High dv/dt of CMV causes leakage currents, which create noise problems to the equipment installed near the converter. This paper presented modulation strategy to eliminate CMV three level T-Type inverter (Zero CMV 3L T2I) that substantially eliminates CMV. The principles of selecting suitable triangle carrier signals for the T-Type is described. This PWM control method can mitigate the peak value to 95% as compared to the conventional sinusoidal pulse width modulation method. A prototype is constructed to verify the operating principle of the three-level T-Type inverter. Simulation and experimental results are presented.

Performance evaluation and comparison of diode clamped multilevel inverter and hybrid inverter based on PD and APOD modulation techniques

<p>The popularity of multilevel inverters have increasing over the years in various applications without use of a transformer and has many benefits. This work presents the performance and comparative analysis of single phase diode clamped multilevel inverter and a hybrid inverter with reduced number of components. As there are some drawbacks of diode clamped multilevel inverter such as requiring higher number of components, PWM control method is complex and capacitor voltage balancing problem, an implementation of hybrid inverter that requires fewer components and less carrier signals when compared to conventional multilevel inverters is discussed. The performance of single phase diode clamped multilevel inverter and hybrid multilevel inverter for seven, nine and eleven levels is performed using phase disposition, alternate phase opposition disposition sinusoidal pulse width modulation techniques. Both the multilevel inverter are implemented for the above mentioned multicarrier based Pulse Width Modulation methods for R and R-L loads. The total harmonic distortion is evaluated at various modulation indices. The analysis of the multilevel inverters is done by simulation in matlab / simulink environment.</p>

Development of miniature spherical ultrasonic motor using wire stators

The purpose of this study is to develop a miniature motor for directional adjustment of a vascular endoscopic camera. Spherical ultrasonic motor not affected by magnetic fields is used in the miniature motor. The characteristic of spherical ultrasonic motor is that one motor has multi degree of freedom in rotational direction. Wire is used as stator to realize miniaturization of the motor, so it is called miniature spherical ultrasonic motor using wire stators. Firstly, the pressing force between a stator and a spherical rotor is discussed, which is important for developing a miniature spherical ultrasonic motor using wire stators. As a result, it can be clarified that there is an optimum value for the pressing force. Secondly, the starting torque is investigated, which is one characteristic of the miniature spherical ultrasonic motor using wire stators. The relationship between the frequency and amplitude of the applied AC voltage and the starting torque is clarified. Finally, the control method of the rotational direction of a miniature spherical ultrasonic motor using wire stators is discussed. A PWM control method is proposed to control the rotational direction of an ultrasonic motor. In this PWM control, traveling wave and standing wave generated on a wire stator are used. Experimental results show that the proposed method is effective.

Modeling and Simulation of Photovoltaic Grid-connected Inverter

Based on the topology of diode clamped three-level inverter, this paper introduces the working principle and control method of the inverter. This paper focuses on the midpoint potential balance problem and PWM control method of Diode-clamped three-level inverter and the SVPWM control method developed thereby. In this paper, the analysis of inverter topology and control method is focused on the maximum power point tracking problem and phase-locked loop problem in photovoltaic grid-connected process. This paper proposes a complete system for photovoltaic grid connection using inverters. At the end of this paper, the results of simulation and analysis of the system using computer software are given.

Power Supply Redundancy Design of Aircraft's Electric Braking Electro-Mechanical Actuation System

In this paper, a power source redundancy-optimization approach for aircraft electrical brake electromechanical actuation system was proposed. The PWM plus phase-shift (PPS) control method was introduced in Dual active half bridge, which limited the amplitude of transform's leakage inductance current, thus expanding the fluctuation range of input voltage. Then, the voltage gain formula was deduced. By analyzing the leakage current under different phase shift in one period, the average power and root-mean-square (RMS) value of leakage current can be compared. Then, the optimum modulation range of phase shift can be obtained. By analyzing the soft-switching operation in this range, all switches can realize zero-voltage-switching (ZVS). To ensure the output voltage stability and voltage balance across the leakage inductance, a closed loop control method is designed. Finally, a prototype of 28V/270V-1kW was built to verify the theoretical analysis and calculation.