Physical Process Of Four-step Commutation Of Bidirectional IGBT Switches In Matrix Converters

Matrix converter is a new type of direct AC-AC converter using bi-directionalswitch for power transmission. It has gradually attracted a lot of attention by virtue ofits excellent input and output characteristics. Matrix converters have many advantagesover the traditional AC-AC converters and AC-DC-AC converters. One of the keytechnical issues that influence the practical matrix converter is the commutationproblem among different phases, which has been a subject of intensive investigation.Based on the comparative analysis of various voltage source matrix convertersand current commutation methods, we focus our study on the most commonly usedfour-step commutation method.Firstly, we developed simulation model of3-phase to3-phase matrix converter inMatlab. Depending on the input and output signals, we select4sampling time pointsduring one cycle of the output current waveform. We select2-input to1-output as thebasic topology, simulate the characteristics of these sampling points in PSPICE, studythe voltage and current waveforms, and verify the current model of four-stepcommutation strategy of reliability and feasibility.Secondly, we study the impact of the system parameters on the m atrix converterin the four-step commutation process. We focus on the influences of input voltage,output current, the gate resistance and line stray reactance change on matrix converterin four-step commutation switch process and the switching loss. We have built a fourstep commutation of matrix converter experiment setup using IGBT and HCPL316Jdrive circuit,TMS320F2812DSP, and further verify the effect of the change of systemparameters in the four-step commutation process.Finally, we compare three kinds of two-way switch four-step commutationcharacteristics from the switching stress of the devices and loss. We introduce thecalculation method of IGBT switching losses, and analyze the matrix converterfour-step commutation process with three types of bidirectional switches.Comparative study of different bidirectional switches, switch difference of stress andlosses, research shows that RB-IGBT switch in the four-step commutation switchoffers the minimum stress and loss, more suitable for matrix conve rter.In this thesis, through the analysis of matrix converter, the four-stepcommutation process of the theory, the software simulation and the experiment platform, it draw some meaningful conclusions. The results of this study not only hasimportant significance in improving the current technology in matrix converter, butalso has an important reference value in practical application for promoting the matrixconverter in practice.