Research On Control Strategy Of Suppression Of Common Mode Voltage Of Matrix Converter

Matrix converter is a direct AC-AC frequency conversion device type, have th e important characteristic of the variable frequency power supply: input and outpu t with a sinusoidal; for any load can achieve input power factor of 1; direct energ y bidirectional flow meet the requirements of the motor four quadrant operation; wit hout DC link energy storage elements, conform to the development direction of mo dular. At present, there are many factors that plagued the matrix converter practica l, one of the main reasons is the matrix converter commutation. Commutation strat egy is reliable or not directly related to the safe operation of matrix converters, is one of the technical difficulties of matrix converter. Because of the control algorith m and the input and output waveform limits, there are over voltage pulse in the o utput line voltage in space vector modulation strategy. At the same time, the matr ix converter output voltage will be produced inevitably in the high-frequency comm on mode signal, causing great harm to the load and the electrical equipment.In this paper, a detailed analysis of the traditional four step commutation an d two step commutation strategy proposes an improved two step commutation strat egy. Different combinations of the strategies by three-phase switching solution for loa d current detection caused by inaccurate commutation failure, can not only guarant ee the reliability of commutation, reduction of commutation time, but also improv e the quality of the output waveform. The two step commutation of the indirect sp ace vector matrix converter simulation model is built based on Matlab/Simulink si mulation platform, the simulation results proved that the two step commutation strat egy is correct and reliability. Analysis of the common mode voltage output matrix c onverter and voltage pulse generation mechanism, aiming at the problem of over vol tage pulse of the conventional matrix converter to reduce common mode voltage mo dulation strategy is optimized output linevoltage, by adjusting the four effective vect or duty cycle to achieve reduction of the common mode voltage and effectively eli minate the output line voltage over voltagepulse. The model of indirect space vectormodulation of two step commutation strategy of time effectively adjusted based o n vector function, simulation results verify the correctness and effectiveness of the improved theory.Finally, this paper designed and implemented with DSP and CPLD as the cont rol unit of the matrix converter vector control system platform, verify the feasibility of the method and the correctness of the use of the platform, and provides a reli able experiment environment for further study.