Three-phase Power Factor Correction Converter Research Articles

A Review of Three Phase AC-DC Power Factor Correction Converters for Electric Vehicle Fast Charging

Electric vehicle charging station for fast DC charging performs AC-DC conversion at off-board. In recent years, three-phase AC-DC power factor correction (PFC) converters are dealt with fast charger. These converters are developed using unidirectional and bidirectional power flow structure. In this study, three-phase AC-DC PFC converter topologies, providing bidirectional power flow, are evaluated in terms of performance. The aim is to present the latest technology of bidirectional multilevel AC-DC PFC converters for EV fast charging. This paper provides a comprehensive and practical review for researchers interested in fast charging infrastructure for electric vehicles.

Analysis and Design of Interleaved DCM Buck–Boost Derived Three-Phase PFC Converter for MEA

In more-electric aircraft (MEA), the synchronous generators are connected directly to the turbo engine to develop a constant-voltage variable-frequency (CVVF) ac supply bus. In addition, the MEA has adopted a high-voltage dc bus in its power system to cater to the various categories of load used by aircraft. Therefore, this change in power paradigm has created a requirement for ac-dc power factor correction (PFC) converters to convert CVVF ac to constant dc with high power quality in a reliable manner. In this article, a three-phase interleaved buck-boost-derived PFC converter is operated in discontinuous current conduction mode to realize the inherent unity power factor (UPF) operation for MEA wide range of supply frequency. The benefits of the proposed converter are higher power density, efficiency, and reliability. The advantages of the proposed converter are demonstrated by performing an analytical comparison with the single-cell three-phase buck-boost derived PFC converter and presented the relevant results. The experimental results from a 2.0-kW laboratory concept-proof hardware prototype have been provided to confirm the proposed converter UPF operation for a wide range of supply frequencies. A low input power factor of 0.9996 and a minimum current THD of 2.52% are recorded from the developed prototype.

Design and Implementation of Four-Switch Current Sensorless Control for Three-Phase PFC Converter

Four-switch current sensorless control for three-phase four-switch converter with power factor correction (PFC) function is presented in this letter. In comparison with conventional multiloop control methods, the proposed control strategy requires sensing of two line voltages and two capacitor voltages only to achieve PFC function. As there is no sensing current, the proposed sensorless control scheme reduces the cost and complexity of design. The performance of the proposed control is validated by its implementation in digital signal processing (DSP) TMS320F28335, and the result shows that the proposed scheme is able to provide comparable PFC performance without sensing current.

Универсальный подход к исследованию AC/DC-преобразователей повышающего типа

Three-phase AC/DC boost converters performing power factor correction are widely used at present. They ensure electromagnetic compatibility of the converter with the network and decrease the network load by making the phase currents proportional and co-phase with the phase voltages. Typically, a three-phase AC/DC boost converter contains input power reactors and a three-phase bridge rectifier. Better power factor value is achieved in such devices by applying three choppers based on bidirectional power switches or power transistor legs. However, a large number of controllable devices and components, the current states of which depend on their pre-switching state, is a factor that adds much difficulty to studying the electrical processes in the converter. A principle of reducing the number of equivalent circuits necessary for studying the electrical processes in the converters under consideration is described. The proposed principle follows from assumptions based on the target operating mode of an AC/DC boost converter. Three converters have been investigated by applying this principle of reducing the number of equivalent circuits with using the electric circuit theory (Kirchhoffs equations or the mesh-current method) techniques. Examples of applying the proposed approach for studying three-phase AC/DC boost converters (so-called Vienna rectifiers) are given. The proposed approach made it possible to decrease the number of analyzed equivalent circuits down to eight ones, and the conclusions drawn from an analysis of the obtained equivalent circuits were used to select the best configuration of a three-phase AC/DC boost converter. The obtained results are of interest for developers of three-phase power factor correction converters, uninterruptible power sources, frequency converters, and other AC/DC converters complying with more stringent requirements for the power factor, efficiency, and device prime cost.

Design of 10kW three-phase EV charger with wide output voltage range based on voltage-fed isolated PFC converter

ABSTRACTThis article presents a design of the three-phase Electric vehicle (EV) charger with a wide-output voltage range. The proposed charger is based on a voltage-fed/isolated power factor correction (PFC) converter followed by a non-isolated DC/DC converter. The three-phase PFC converter come from asymmetrical dual active bridge (ADAB) converter having zero-voltage- and zero-current-switching (ZV-ZCS) operation in the primary side so that a low-cost device such as Insulated gate bipolar junction transistor (IGBT) is available despite of a high switching frequency. Also, since the PFC converter adopts the harmonic modulation technique that can be implemented in a simple equation, all the controls for the three-phase PFC converter and the non-isolated DC/DC converter can be implemented with a simple digital controller by excluding fast current loops for input current harmonic regulation. The feasibility of the proposed charger has been verified with a 10kW prototype.

Robust Model-Predictive Control for a Compound Active-Clamp Three-Phase Soft-Switching PFC Converter Under Unbalanced Grid Condition

Two main problems, including unbalanced grid input and circuit parameters uncertainty in the three-phase soft-switching converter control system, are considered in this paper. First, the constant-switching-frequency model-predictive control (CF-MPC) is improved for application in compound active-clamp zero-voltage-switching three-phase power factor correction converter. Second, a robust-constant-frequency model-predictive control (RCF-MPC) method is proposed for current loop; the novel contributions are: 1) the negative-sequence current component is introduced into the cost function of the model-predictive control to decrease the influence of unbalanced grid input; and 2) a robust item is added into the predictive model to reduce the influence of the circuit parameter uncertainty. Third, a robust variable structure controller is proposed for voltage loop considering the capacitor and load uncertainty. The simulation and experiment results show that, compared with the original CF-MPC method and the traditional proportional–integral control method, the proposed RCF-MPC method decreases the total harmonic distortion under the unbalanced grid condition. Meanwhile, the voltage loop robust variable structure controller has better transient and steady-state performance with respect to the load perturbation.

An Integrated Control Strategy for a Fast Start-Up and Wide Range Input Frequency Operation of a Three-Phase Boost-Type PFC Converter for More Electric Aircraft

This paper presents an integrated control strategy to achieve fast start-up and enable wide input frequency operation in a three-phase six-switch power factor correction (PFC) converter. Limiting the inrush current with simultaneously minimizing the start-up time is achieved by implementing a nonlinear compensator in the voltage control loop. In addition, the concerning issues regarding unity PFC operation with an accurate reference tracking in a system with wide input frequency variation (typical for more-electric-aircraft) are resolved by a second-order compensator integrated with a state-feedback controller in the current loop. For a proof-of-concept verification, a hardware prototype of 6 kW, three-phase six-switch PFC is developed and tested with the proposed integrated control strategy in a wide source frequency range (360–800 Hz) ac input that shows perfect unity power factor operation throughout. Both the start-up time and inrush current are reduced to $ of their values in conventional PI compensation.

A duty cycle generation scheme for the three‐phase single‐stage full‐bridge PFC in balanced‐grid

In this Letter, the duty cycle generation scheme is presented and implemented, which can improve the input performances of the three-phase single-stage full-bridge power factor correction (PFC) converter. The analysis and discussion is aiming at the operation of the PFC converter in balanced grid condition. On the basis of the instantaneous expression of the three-phase input current, the ideal duty cycle of each phase is obtained. To achieve a good PF for each phase, a simplified duty cycle generation scheme is presented and implemented in the three-phase PFC converter. The simulating and experimental results based on a 500 W prototype show that after adoption of the presented duty cycle generation scheme, a higher PF has been achieved for each phase of the three-phase PFC converter.

An Optimized PI Controller Design for Three Phase PFC Converters Based on Multi-Objective Chaotic Particle Swarm Optimization

The compound active clamp zero voltage soft switching (CACZVS) three-phase power factor correction (PFC) converter has many advantages, such as high efficiency, high power factor, bi-directional energy flow, and soft switching of all the switches. Triple closed-loop PI controllers are used for the three-phase power factor correction converter. The control objectives of the converter include a fast transient response, high accuracy, and unity power factor. There are six parameters of the controllers that need to be tuned in order to obtain multi-objective optimization. However, six of the parameters are mutually dependent for the objectives. This is beyond the scope of the traditional experience based PI parameters tuning method. In this paper, an improved chaotic particle swarm optimization (CPSO) method has been proposed to optimize the controller parameters. In the proposed method, multi-dimensional chaotic sequences generated by spatiotemporal chaos map are used as initial particles to get a better initial distribution and to avoid local minimums. Pareto optimal solutions are also used to avoid the weight selection difficulty of the multi-objectives. Simulation and experiment results show the effectiveness and superiority of the proposed method.

A Passive Flyback Auxiliary Circuit with Integrated-Transformer Suitable for Three-Phase Isolated Full-Bridge Boost PFC Converter

A passive flyback auxiliary circuit with integrated transformer is proposed and investigated in a three-phase isolated full-bridge boost power factor correction (PFC) converter, by which the voltage across primary side of the power transformer can be clamped to a fixed value and the absorbed energy can be transferred to the load by itself automatically. The auxiliary circuit is composed of two capacitors, four diodes, and one flyback integrated transformer. With the help of the flyback integrated transformer, synchronous resonances in the auxiliary circuit can be achieved, which will avoid the unbalance of the voltage and current in the auxiliary circuit. Compared with the passive snubbers, voltage spike of the three-phase PFC converter is suppressed more effectively with the adoption of the auxiliary circuit, and current stress of the switches is much lower. The operational principle of the auxiliary circuit is discussed in the three-phase isolated full-bridge boost PFC converter. Furthermore, the design considerations of the auxiliary circuit are analyzed. Finally, experimental study of the auxiliary circuit has been done on a laboratory-made three-phase PFC prototype, and the feasibility of the proposed method and the validity of the theoretical analysis are verified by the experimental results.

Three-Phase Power Factor Correction Converter Based on One-Cycle Control in Aircraft Electric Power System

Traditional three-phase PFC converters based on one-cycle control (OCC) exhibit instabi- lity at light load conditions.This will cause much more harmonic current which is harmful to the syterm.To overcome this disadvantage, this paper introduces a modified three-phase power factor correction(PFC) converter based on one-cycle control in aircraft electric power system. The input voltage multiplies a gain and its result is added to the actual sensed current,then the sum of them is compared with the sawtooth waveform to yield switching signal.This is the modified contorl mathod. Finally the MATLAB simulations at heavy and light loads as well as the transfer between them are carried. The simulation results show that the improved control circuit can achieve unity power factor and exhibit stability at light loads.

Parallel connection of single-switch three-phase power-factor correction converters for interleaved switching

A circuit for the parallel connection of multiple high-frequency three-phase power-factor-correction converters is proposed which enables their input and output current ripple to be interleaved. Such interleaved operation substantially improves the composite power factor, line-current ripple and output-voltage ripple. The improvement is investigated by developing solutions to circuit state equations which allow the high-frequency content of the line current, as well as the low-order line-frequency harmonics, to be computed. Conclusions drawn from the computed results are verified experimentally using a 1 kW, two-stage, interleaved converter.