Matrix Rectifier Research Articles

Common-mode voltage suppression of indirect four-bridge matrix converter based on dual-space vector modulation

For the indirect matrix converter topology composed of bidirectional switching matrix rectifier and traditional voltage source Four-bridge inverter, this paper divides common-mode voltage generated by the indirect matrix converter into inverter stage common-mode voltage and rectifier stage common-mode voltage. A dual-space vector modulation strategy that can effectively suppress common-mode voltage of Four-bridge matrix converter was proposed. Reasonable selection of zero vector of rectifier stage can reduce the effective value of common-mode voltage without increasing switching loss and affecting the utilization rate of DC voltage. Two nonzero vectors with equal amplitude and opposite direction near the output reference voltage vector are selected for zero vector substitution in the inverter stage. The indirect Four-bridge matrix converter was simulated by MATLAB / Simulink. The results show that the improved modulation strategy can not only overcome the negative impact of load imbalance, but also effectively reduce the amplitude and effective value of common-mode voltage without changing the utilization rate of intermediate DC voltage.

On Magnetic-coupled Matrix Rectifier Applied to Accelerator Power Supply

The power supply designing of superconducting magnet is vital for magnetic field system in the development of accelerator. Magnet power supply can still be improved in grid-side power factor, and better cost-effective solutions can be sought. For release or consumption of the huge energy stored in the future superconducting magnet, so that it is urgent to carry out related research to solve the energy feedback problem. Utilizing the characteristics of adjustable power factor and bi-directional energy transfer of matrix converter, a novel magnetic-coupled matrix rectifier topology is presented, which is suitable for accelerator power supply. An improved control strategy is proposed to realize sinusoidal waveform of input current, unity input power factor as well as output current tracking the instruction current waveform. Prototype test shows that the matrix converter can realize DC output and the control strategy can achieve expected requirements. Load disturbance experiment of quasi-trapezoidal wave output is preliminarily verified. The matrix converter studied in the paper, as a kind of feasible attractive choice of accelerator power converter topology, has a favorable research prospect.

An Active Disturbance Rejection Control Strategy for a Three-Phase Isolated Matrix Rectifier

Single-stage three-phase isolated matrix rectifiers (TIMRs) have high efficiency and compact configurations and are very suitable for electric vehicle (EV) chargers. However, external and internal disturbances challenge the robustness and tracking performance of EV chargers, and conventional proportional integral (PI) controllers cannot solve the unmodeled dynamics and the uncertainty of model parameters in the system, so other feedback controllers, which have disturbance rejection performance, need to be designed. Therefore, this article proposes a dual-loop control strategy based on active disturbance rejection control (ADRC) to guarantee high-speed dynamic response and strong robustness against disturbances. First, the dynamic model of the TIMR is established and divided into two parts to facilitate the controller design. Second, the extended state observer (ESO) is designed to estimate and compensate for the disturbances of the system, and the inner current loop and the outer current loop are designed based on the second-order ADRC. In addition, a simplified parameter-tuning method of the proposed control scheme is presented in detail. Finally, a frequency-domain analysis is given to explain the robust performance of the proposed control scheme. The effectiveness and feasibility of the proposed controller are verified by simulation and experimental results.

On a Novel Topology of Matrix Converter Applied to Accelerator DC Power Supply

The current topology schemes of heavy ion accelerator power supply have serious pollution to the power grid caused by low power factor of the grid side. Considering the characteristics of adjustable power factor and bidirectional energy transfer of the matrix converter, the possibility of which applied to the accelerator DC power supply is studied and three kinds of backup topology schemes including the preceding regulated matrix rectifier (MR) are proposed in this article. Given the actual situation of accelerator power supply, research has been focused on the modulation strategy suitable for the topology of the preceding regulated MR and simulation validation. Based on simulation of the preceding regulated MR scheme, a matrix power prototype is developed. A power factor tester is utilized to test grid side power factor. According to the experimental results, it is prospectively feasible to apply the preceding regulated MR topology to accelerator DC power supply, with excellent performance of the grid side.

Backstepping Control of High-Frequency Link Matrix Rectifier for Battery Chargers

High-frequency link matrix rectifier (HFLMR) is getting much interest in electric vehicle charger applications due to its high efficiency and compact volume. However, the inputs and outputs of HFLMR are highly coupled resulting in reduced system dynamic performance and robustness. This article proposes a dual closed-loop backstepping control (DCL-BSC) strategy to solve these problems, which consists of a dc output current outer-loop controller and a grid current inner-loop controller. First, the nonlinear mathematical model of HFLMR is established, and the six-segment space vector pulse width modulation scheme is used as the modulation method. Then, the DCL-BSC scheme is designed in detail based on the Lyapunov stability theory. And a compensation method based on the phase-shift angle is developed to realize the unity power factor. Compared with the conventional dual closed-loop PI control method, the proposed method has a better steady-state and dynamic performance, and robustness against system disturbances. Simulation and experimental results are used to verify the effectiveness of the proposed control scheme.

Research on battery control method based on matrix rectifier

In this paper, a battery control method based on matrix rectifier is developed. The matrix rectifier is used to control the current of the input battery. Compared with the ordinary rectifier, it can greatly reduce the disturbance caused by the grid side and internal parameters and ensure the performance of the battery at all charging stages. In addition to stability, this control method can also compensate reactive power factor, and has better dynamic controllability.

High-Frequency Link Matrix Rectifier in Discontinuous Conduction Mode With Reduced Input Current Distortion

High-frequency link matrix rectifier (HFLMR) is advantageous in three-phase isolated ac–dc conversion due to its elimination of dc-link components. However, the input current distortion increases in an HFLMR when it operates in discontinuous conduction mode (DCM). The modulation scheme forms the high-frequency link current shape, which directly affects the input current distortion. Space vector pulsewidth modulation (SVPWM) is a popular modulation method for the matrix-type converter for its flexibility of arranging switching vectors. In this article, a new switching scheme based on SVPWM is proposed for the HFLMR to improve the current quality in DCM without adding complexity to the control. In DCM, the resonance between diode capacitance and transformer leakage inductance becomes a source of converter harmonics and instability. The method of shorting the transformer secondary is implemented to eliminate the voltage and current ringing in the discontinuous period. A 600-W lab prototype HFLMR that converts 115Vrms, 400-Hz three-phase input voltage to 270-V dc output voltage is implemented for experimental verification of the proposed switching scheme and converter topology. With the proposed switching scheme, the input current distortion is effectively reduced. With the proposed topology, the high-frequency voltage and current ringing are eliminated.

Space vector modulation based switching schemes for high frequency link matrix rectifier in discontinuous conduction mode

A high-frequency link matrix rectifier with a pure capacitive output filter has the advantages of reduced converter size and clamped voltage over the rectifier diode. However, when the converter operates in discontinuous conduction mode (DCM), there is high input current distortion. The distortion has to be compensated such that the total harmonic distortion (THD) does not exceed 5%. The straightforward way of reducing distortion is by designing the switching scheme. In this study, switching schemes based on space vector modulation have been studied to improve the input current quality in DCM. Several existing switching schemes and newly proposed switching schemes have been analysed and compared. A 600 W laboratory prototype has been built to verify the effect of switching schemes over input current quality. The experimental results show that the input current THD can be greatly reduced by applying proper switching scheme.

Cost-Effective Matrix Rectifier Operating With Hybrid Bidirectional Switch Configuration Based on Si IGBTs and SiC MOSFETs

For so many years, silicon (Si) IGBTs have been widely utilized in power converters for low-to-medium voltage high-power applications. However, the ever-increasing requirements to improve power density, power quality, and efficiency of power converters have urged researchers to explore alternative technologies such as silicon-carbide (SiC) MOSFETs. SiC devices fill the mentioned gaps with increased voltage blocking capability, higher switching speed, and lower on-state resistance; yet, their price is much more elevated. Both technologies are adopted in matrix rectifiers (MRs), which have recently gained attention for on-board electric vehicle (EV) charger and battery energy storage system (BESS) applications because of their controllable bidirectional power flow and compact size. A MR contains bidirectional switches made up of two power devices, doubling the device count and cost to conventional voltage source converters (VSCs). In this paper, we compare in terms of efficiency four types of MRs, each one consisting of a specific bidirectional switch configuration. Among these switches, we propose a cost-effective hybrid configuration consisting of Si IGBTs and SiC MOSFETs for straightforward commutations during the charging mode of matrix rectifiers. Also, the proposed configuration is compared to other typical bidirectional switch configurations. To perform these comparisons, the switching energy losses in 1200 V commercial IGBTs and MOSFETs, constituting the bidirectional switches, are measured through the double-pulse test (DPT). Performance comparisons of the MRs are supported through a simulator and verified via experimental work, where the proposed arrangement results in a cost-effective solution in MRs operating with switching frequencies up to 50 kHz and further.

Direct Power-Based Three-Phase Matrix Rectifier Control with Input Power Factor Adjustment

In a current source rectifier such as a matrix rectifier, input voltage and current cannot be in phase unless an additional input power factor control technique is implemented. This paper proposes such a technique for a matrix rectifier using power-based space vector modulation (SVM). In the proposed method, the modulation index and phase required in order to apply the SVM are calculated based on the active and reactive power of the rectifier for intuitive power factor control. The active power that the rectifier should generate for the regulation of the output inductor current is obtained by the PI (proportional-integral) controller. The reactive power, which is supplied by the rectifier for adjustment of the power factor, is assigned differently depending on the output condition: for the output condition capable of unity power factor, it is set to a negative value of reactive power of the input capacitor, and when the unity power factor is not achievable, it is set with the maximum reactive power the rectifier can generate under the given condition to attain the maximum possible input power factor. It is determined whether the given condition is the light load condition by comparing the absolute value of the reactive power supplied by the input capacitor with the maximum rectifier reactive power that can be produced under the given condition. The SVM based on the active and reactive power of the rectifier in this technique allows the input power factor control to be intuitive and simple. The performance and feasibility of the technique were proved by simulation and experimentation.

A High-Frequency Link Matrix Rectifier With a Pure Capacitive Output Filter in a Discontinuous Conduction Mode

High-frequency link matrix rectifier (HFLMR) is an isolated single-stage three-phase ac–dc converter, which originates from the three-phase matrix converter and inherits the advantages of matrix rectifier such as no dc-link components. In this paper, an HFLMR for more electric aircraft system is proposed. The proposed HFLMR consists of a three-phase input LC filter, a matrix rectifier, a high-frequency transformer, a diode bridge rectifier, and a purely capacitive output filter. The elimination of output filter inductor clamps the output rectifier device off-state voltage to the output voltage and eliminates any RC snubber across the rectifier. A novel symmetric modulation scheme based on space vector modulation is implemented to regulate the switching sequences and provide selective natural zero voltage switching and zero current switching of the devices of the matrix bridge. The proposed converter is more power-dense since it eliminates the dc-link components, output filter inductor, and lossy snubber across the output rectifier devices. A TI digital signal processor TMS320F28379D is used to process the converter signals and generate the gating logic. The proposed converter is validated on a laboratory prototype powered by 115 $V_{{rms}}$ ac with frequency of 400 Hz. The isolated dc output voltage is regulated at 270 V dc and the maximum output power is 600 W.

Power Factor Control Method Based on Virtual Capacitors for Three-Phase Matrix Rectifiers

This paper proposes a novel input power factor control method based on a concept of virtual capacitors to provide unity input power factor for three-phase matrix rectifiers. The proposed algorithm introduces, at the input terminal of the matrix rectifier, an imaginary input capacitor generated by modifying a reference vector of the space vector modulation method. The virtual input capacitor, which is fictitiously built in parallel with an input LC filter, successfully compensates for the leading power factor of the LC filter of the matrix rectifier. Thus, the proposed method yields a unity power factor operation despite the presence of the LC filter of the three-phase matrix rectifier. In addition, under a condition when the unity power factor operation cannot be realized, the proposed algorithm adjusts a virtual capacitance to obtain a maximum achievable power factor operation. Because the proposed technique yields the input power factor control by introducing the virtual capacitor and adjusting a reference space vector, the proposed algorithm can be easily incorporated with conventional space vector modulation algorithms for the three-phase matrix rectifiers. Thus, the proposed method can control input power factor without employing proportional–integral controllers used in conventional power factor control methods for the matrix rectifiers, leading to simple control structure and straightforward tuning process for power factor control.

Application of Model Predictive Control to Ultra Sparse Matrix Rectifier

Ultra Sparse Matrix Rectifier (USMR) is considered to be one of the simplest and compact three-phase PWM rectifiers. It is a buck three-phase AC-DC converter with one-quadrant operation capability. In this paper, Model Predictive Control (MPC) is applied to USMR supplying inductive load. The discrete time model of the system is derived. Then, the MPC algorithm for the proposed system is discussed. Finally, the system is simulated using Matlab. The performance of the proposed USMR controlled using MPC is compared to the one using Space Vector Modulation (SVM). Simulation results show that the MPC has more harmonic performance benefits than the SVM one. However, the efficiency of the system that uses MPC is slightly lower than the one that uses SVM, due to the built in switching loss minimization of the SVM.

Global Sliding Mode Control based on a Hyperbolic Tangent Function for Matrix Rectifier

Global Sliding Mode Control based on a Hyperbolic Tangent Function for Matrix Rectifier

Improved Quasi Sliding Mode Control with Adaptive Compensation for Matrix Rectifier

Improved Quasi Sliding Mode Control with Adaptive Compensation for Matrix Rectifier

Z‐source matrix rectifier

This study presents a novel Z-source matrix rectifier (ZSMR). To overcome the inherent disadvantage that the voltage transfer ratio for traditional matrix rectifier (MR) cannot be more than 0.866, a Z-source network has been combined with the MR. The proposed rectifier realises a voltage-boost function and the Z-source network also serves as power storage and guarantees double filtration grade at the output of the rectifier. The open-circuit zero state is required to obtain the voltage-boost function and ensure the output angle of the current vector to be invariant to obtain the expected power factor. In addition, to widely extend the voltage transfer ratio of the proposed rectifier, this study presents the switched-inductor matrix rectifier (SL-ZSMR) and tapped-inductor matrix rectifier (TL-ZSMR). The corresponding circuit topologies, control strategies and operating principles are introduced. Both simulation and experimental results are shown to verify the theoretical analysis.

Analytical Models of Power Losses of a Three phase AC-DC Rectifier for Hybrid Electric Vehicles

This paper presents the investigation of analytical models for the approximation of conduction and switching losses of the power-switch network in a three-phase AC-DC matrix rectifier. Analytical models of conduction and switching losses can provide circuit designers with a measurable way to approximate the total losses of the given power converter at different operating points so as to estimate the trend of the loss versus the change of the operating points.

A Sliding Mode Control Design based on the Reaching Law for Matrix Rectifiers

This paper presents a novel approach for achieving both a tight DC voltage regulation and a power factor control by applying the Reaching Law Sliding Mode Control (RL-SMC) and the conventional Sliding Mode Control (SMC). Applying these strategies on a matrix rectifier (MR) can achieve a unity grid side power factor when the DC load changes widely and it can provide a ripple-free output voltage that is easily affected by distortions of the three-phase ac voltage supply. Furthermore, by employing the reaching law on the SMC can solve the chatting problem of the sliding motion. Comparative Matlab simulations and experimental verifications for these strategies have been presented and discussed in this paper. The results show that by applying the SMC and RL-SMC on a MR can achieve a unity grid side power factor and a regulated ripple-free DC output.

Applying Reduced General Direct Space Vector Modulation Approach of AC–AC Matrix Converter Theory to Achieve Direct Power Factor Controlled Three-Phase AC–DC Matrix Rectifier

This paper presents a novel approach to achieve both tight dc voltage regulation and direct power factor control by applying general direct space vector modulation (G-SVM) of matrix converter theory to a three-phase ac–dc matrix rectifier. The reduced form of G-SVM and the derivation of the three-phase ac–dc matrix rectifier from a three-phase ac–ac matrix converter are described and theoretically justified. The proposed matrix converter features intrinsic buck conversion, tight output voltage regulation via modulation, inherent capability of four-quadrant operation, elimination of the bulky storage component on the dc bus, and sinusoidal input current. Moreover, the reduced G-SVM-controlled three-phase ac–dc matrix rectifier can achieve leading, lagging, or unity input power factor by simple and direct control of the input current displacement angle. This significantly benefits the potential application of the reduced G-SVM-controlled three-phase matrix rectifier to automotive, aircraft, ship, and other three-phase standby dc supplies. In these applications, the unity power factor control is indispensable when the dc load widely changes. Simulated and experimental verification for this strategy has been presented and discussed in this paper.

ENGLISH

2 ABSTRACT: Artificial Neural Networks (ANN) is introduced by McCulloch and Pitts in 1943. It is an interconnected group of nodes. Neural networks models in artificial intelligences are usually referred to as artificial neural network. A novel unity power factor battery charger conception based on an Ultrasparse Matrix Rectifier (USMR) with Artificial Neural Network (ANN) is presented in this paper. Ultrasparse matrix converter topology can be derived from Indirect converter topology having a reduced number of input switches. The circuit has only three switching components and low-energy- conversion loss. This reduces the cost and enhances the system's efficiency for high voltage battery. Thus, the proposed ANN controller improves the line power quality and delivers admissible output power to the battery. The charging method chosen is the Constant Current (CC) or Constant Voltage (CV) method. The ANN control and space vector modulation algorithms are implemented with the Digital Signal Processor.