This paper presents a review of the most popular control and modulation strategies studied for matrix converters (MCs) in the last decade. The purpose of most of these methods is to generate sinusoidal current on the input and output sides. These methods are compared considering theoretical complexity and performance. This paper concludes that the control strategy has a significant impact on the resonance of the MC input filter.

A Review of Control and Modulation Methods for Matrix Converters

A novel voltage-based commutation (VBC) strategy without explicit input-voltage measurement is proposed in this paper. By properly selecting the width of the critical intervals, the two-step uncritical commutation and four-step critical commutation approaches are utilized to realize safe VBC. The general switching patterns of space-vector modulation (SVM) are analyzed, and the four-step critical commutations are avoided by using four selected SVM switching patterns; thus, all the commutations in the matrix converter can be achieved by two-step VBC. In order to prevent the commutation processes from being interrupted, the triple-zero-vector switching pattern and the single-zero-vector switching pattern are utilized by selecting an appropriate commutation time and the output-voltage/current distortion is minimized. Prototype experiments have been carried out to show the validity of the control strategies.

Implementation of Voltage-Based Commutation in Space-Vector-Modulated Matrix Converter

A filter is required to eliminate the high-frequency switching ripple present in the input current of a matrix converter (MC). Design of such a filter requires an estimation of the higher harmonic components present in the input current. This paper presents a simple closed-form analytical expression for the RMS input current ripple injected by the MC. The expression shows the variation with load power factor and is independent of the output frequency. This is used in a step-by-step procedure to design various input filter components from the specifications of allowable total harmonic distortion in the grid current and distortion in the input voltage. The MC is modeled for the grid frequency component in order to evaluate the design for input power factor and voltage drop across the filter. A damping resistance has been designed ensuring minimum ohmic loss. The analytical estimation of the ripple current and the proposed design procedure have been validated by simulations in MATLAB/Simulink and experiments on a laboratory prototype.

Systematic Input Filter Design of Matrix Converter by Analytical Estimation of RMS Current Ripple

An isolated single-stage three-phase ac–dc converter is proposed for aircraft system in this paper. The proposed converter uses the matrix ( $3 \times 1$ ) topology to directly convert three-phase line frequency ac voltages into high-frequency ac voltage, and therefore facilitates the use of high-frequency transformer for galvanic isolation leading to more compact and lighter weight of the power electronic converter. A space vector modulation-based switching scheme is proposed and digitally implemented for superior input power quality and improved power conversion efficiency. A current doubler rectifier (CDR) circuit is used at the output side, which essentially reduces the leakage inductance of the high-frequency transformer by decreasing the primary to secondary turns ratio. Moreover, an active soft-switched lossless snubber circuit is proposed to overcome the high voltage spikes produced due to the leakage inductance of the high-frequency transformer. A novel approach of adding a series capacitor in the primary winding of the high-frequency transformer for the soft and uninterrupted commutation of the high-frequency ac current is presented. The modes of operation of the proposed converter with the CDR circuit are analyzed in detail. Subsequently, the design equations for the proposed converter are derived. Simulation and experimental results are presented for a 500-W prototype converter suitable for aircraft systems.

A Single-Stage Matrix-Based Isolated Three-Phase AC–DC Converter With Novel Current Commutation

Energy security is one of the most crucial factor in the development of any nation. Interconnections among different power system networks are made to lower the overall price of power generation as well as enhance the reliability and the security of electric power supply. Different types of interconnection technologies are employed, such as AC interconnections, DC interconnections, synchronous interconnections, and asynchronous interconnections. It is necessary to control the power flow between the interconnected electric power networks. The power flow controllers are used to (i) enhance the operational flexibility and controllability of the electric power system networks, (ii) improve the system stability and (iii) accomplish better utilization of existing power transmission systems. These controllers can be built using power electronic devices, electromechanical devices or the hybrid of these devices. In this paper, control techniques for power system networks are discussed. It includes both centralized and decentralized control techniques for power system networks. This paper also presents a comprehensive review of HVDC interconnections, asynchronous AC interconnections, synchronous AC interconnections and different types of power flow controllers used in these interconnections. Moreover, some important and multivariable flexible AC transmission system (FACTS) devices such as UPFC and IPFC are also discussed with their merits and limitations. Finally, a new asynchronous AC link called flexible asynchronous AC link (FASAL) system is also described in detail. At last, a summary of the comparative analysis of power system link and power flow controllers is given based on recent publications. More than 400 research articles and papers on the topic of power transfer control are covered in this review and appended for a quick reference.

/pdf/a-comprehensive-review-of-power-flow-controllers-in-vd21jbfrl7.pdf

A Comprehensive Review of Power Flow Controllers in Interconnected Power System Networks

This paper deals with the input filter design of matrix converter Regard the matrix converter as a buck type PWM rectifier in the input side, the transfer function of input current using LC input filter is deduced The parameter selection approach for the capacitor and inductor is presented It has been verified that when LC circuit is adopted in the input filter, the input current will oscillate near the LC resonant frequency in both steady state and start-up process for the very low damping factor, and then the input current waveforms will be distorted An improved input filter topology to increase the damping factor is then presented, and the damping resistance parameter selection method of the input filter is presented based on frequency response approach To avoid the current spike at the start-up process, a start-up circuit is then proposed The improved input filter has been tested on a 55kW matrix converter prototype and good performances are achieved

Damped input filter design of matrix converter

Control method for matrix transforming machine and its device

An improved space vector modulation (SVM) approach for matrix converter (MC) operation in unbalanced and non-sinusoidal input voltage condition was presented. The concept of modulation vector was introduced, and the relationship of output voltage and input voltage of MC by space vector denotation was deduced. Using the modulation vector approach, an improved SVM approach was proposed to improve the output performance of MC in abnormal input voltage conditions. The novel approach was based on dynamic control of the output voltage modulation vector respect to the instantaneous input voltage vector. By this method, the unbalanced and non-sinusoidal input voltages could be automatically compensated without any extra calculation so the output voltage could keep balanced and sinusoidal in expected value. The validity of the improved SVM approach was verified by simulation and experiments.

Space vector modulated matrix converter under abnormal input voltage conditions

The invention discloses a space vector modulating method for reducing narrow-pulse phenomenon of a matrix converter; the method is characterized in that: when the minimum value of time duration of a switch state of four effective vectors in a certain modulating period is less than two times of current-conversion time, three zero vectors are adopted for modulation in the modulating period and are respectively added before a first effective vector, between a second effective vector and a third effective vector, and after a fourth effective vector, and the sum is equal to total time duration T0 of the zero vectors. On the premise of not changing the time duration of the effective space vector, the method radically avoids the phenomenon of narrow pulse caused by that the time duration of the switch state is less than current-conversion time, and solves the problem that the output waveform is distorted caused by narrow pulse and greatly improves the output waveform quality and low-voltage regulating range of the matrix converter when a lower modulating ratio is adopted. When the narrow pulse does not appear, a traditional modulating method is still adopted to reduce switching loss and ensure high modulating ratio. The method only needs to regulate the modulating way of the space vector, and is simple and practicable.

Space vector modulating method for reducing narrow-pulse phenomenon of matrix converter

This paper deals with the performance improvement of the matrix converter induction motor drive system. Rotor-flux-oriented vector control strategy is adopted in the drive system, and a novel current loop control scheme is proposed to realize decoupled control of the magnetizing current and the torque current with a unique controller. The output voltage error caused by voltage-based two-step commutation process and the switching device on-state voltage drop are analyzed in detail, and then a compensation method is proposed to eliminate the output voltage error. Using the compensation method, the command output voltage can be used as actual one in motor drive applications, and the measurement errors in the output acquiring circuit are avoided. Simulation and experimental results are presented to illustrate the validity of the proposed methods.

Xingwei Wang

Papers

Damped input filter design of matrix converter

Control method for matrix transforming machine and its device

Space vector modulated matrix converter under abnormal input voltage conditions

Space vector modulating method for reducing narrow-pulse phenomenon of matrix converter

Vector control of induction motor based on output voltage compensation of matrix converter