Based On The Indirect Matrix Converter Multi-motor Drive High Performance Speed Control System Research

Indirect matrix converter (IMC) exists DC link, which could be connected multiple inverters, constitutes a multi-drive system. Multi-drive system based on indirect matrix converter with high quality input/output waveforms, high power density and high compact, is very applicable in adjustable speed drive system of AC motors. In this paper, the control strategy and the key technology of multi-drive system based on indirect matrix converter is investigated.A new topology of multi-drive system based on indirect matrix converter is introduced in this paper. The rectifier stage and the k-inverter stage are combined to achieve the modulation. A method of zero-vector overlapping PWM switching pattern is deduced, analyzes the influence to the output and input performance. Zero current commutation in the rectifier side can be realized, and the switching frequency in the inverter can be reduced, greatly reduce the switch loss, improve the efficiency of the converter.The influence of the abnormal input conditions, such as unbalanced input voltage and instantaneous voltage sag in the source, on the operation performance of multi-drive system based on IMC is analyzed. The topology of multi-drive system based on indirect matrix converter and energy flow are complexity, the output is directly related to the input. It would be adopted suitble compensation control strategy under unbalanced input voltage when the multi-motor works in electric operating status. In this paper, based on instantaneous power theory, a compensation control strategy is introduced, which control the input active power, construct the input currrent vector, and add to the rectifer varies modulaton ratio to improve the output waveform. A compensation scheme for instantaneous voltage sag is proposed. In order to ensure the stability of the DC link voltage, the modulation ratio of the rectifier stage must achieve the purpose of real-time compensation.The input reactive power formula is calculated, and the adjustment range of actual reactive power is given. Precise control of reactive power can be achieved by adjusting the input power factor angle, which can achieve the grid reactive power compensation.This paper proposes a multi-motor vector control method based on the IMC. A control strategy for the drive system, which combines vector control technology for motors and SVPWM algorithm for multi-drive system based on IMC, is proposed. Independent control of multiple motors can be achieved and get a better steady and dynamic performance.Experimental study of single motor vector control in the indirect matrix converter is deduced. The DSP controller is used to induction motor vector control, the CPLD is used to achieve the four-step commutation converter and the dead control, which achieved some results.