Vector Control Of The Permanent Magnetic Synchronous Motor System Based On Matrix Converter

Permanent magnet synchronous motor (PMSM) has found widespread applications in the fields of national defense, industry, aviation and ship-building, etc., with its simple structure, high power density and fast dynamics.The evolution of vector control technology has enabled PMSM to possess as good performance as that of DC motors and become the preference of modern drive systems. Also AC-AC matrix converters hold good potentialities in AC drive systems owing to its unity power factor, without bulky capacitors, and sinusoidal input currents. Therefore, the combination of the PMSM vector control and the matrix converter has recently arrested substantial attentions from scholars both at home and abroad.The present paper presents the research on the vector control system of the matrix converter-permanent magnet synchronous motor (MC-PMSM) based on two modulation strategies of current hysteresis-loop control and double space vector modulation, and introduces theoretical analyses and simulation research about the implementation method, the input current quality and the speed regulating performance of the system. The MC-PMSM system prototype is designed and implemented, in which the digital signal processor (DSP) and the complicated programmable logic device (CPLD) act as the control units. Then experiments are also performed.Main contents concerned in the paper are as follows:The switch state combinations of MC-PMSM vector control system, which is based either on the current hysteresis-loop control or on the double space vector modulation, are analyzed at full length, providing basis for the designing of the control system.The experiential formula is derived for calculating the current-loop width of the MC-PMSM system based on the current hysteresis-loop control. The reasonable current-loop width determined by calculation and simulation analysis results in good input current waves and speed-regulating characteristics. The present paper also presents an improved current hysteresis-loop control approach in which three-phase-input voltages are divided into 12 sections and 3 pairs of current control signals are produced by comparing the reference values and the measured values of the output currents based on double current loops. The switch states of the MC-PMSM are deduced according to the section number of the input voltages and one of the 3 pairs of current control signals. Hence the 5th harmonic, the 7th harmonic, and the total harmonic distortion (THD) of the input currents are obviously reduced and the input currents of the system become more sinusoidal.In the MC-PMSM system based on the double space vector modulation, the expressions for calculating such parameters as the voltage vector magnitude, the voltage vector angle are provided in the paper. Also in this paper, the magnitude of the common-mode voltage of the system is analyzed and the method of choosing reasonable zero-vectors to restrain the common-mode voltage is presented. Based on the research, it is highly recommended that zero vectors, input current vectors, and output voltage vectors should be arranged according to certain rules so as to get as fewer switch times as possible.Finally, the platform of the MC-PMSM vector control system is constructed in the present research on which the correctness and feasibility of the methods provided in the paper are verified, highlighting the significance of the present research for further researches.