Research On Control System Of The Six-Phase Induction Motor

With the development of computer control technology and power electronics, six-phase induction motor control system has been widely used in power control area due to its advantages. Because of the lower torque ripple and high reliability in the process of operation, the six-phase induction motor is often used in mining and other industries. In this thesis, the SVPWM control strategy of the six-phase induction motor is studied, and the third harmonic is injected in the system. Finally the whole six-phase induction motor control system is realized.First, this thesis introduces the structure of the six-phase induction motor windings briefly, and establishes the mathematical model of the six-phase induction motor, then deduces the flux equation, voltage equations, electromagnetic torque equation and the motion equations of the six-phase induction motor. Through the study of the space decoupling technology of the six-phase induction motor, the SVPWM control of the six-phase induction motor is realized. Through the study of single-phase induction motor SVPWM control technology, combined with the six-phase induction motor winding structure, a novel six-phase induction motor SVPWM control strategy is proposed. a simulation model of six-phase induction motor control system is build in MATLAB to verify the algorithm.Secondly, the magnetic of six-phase induction motor and the relationship between the six-phase induction motor harmonic and magnetic potential are studied. Through the studying of the third harmonic voltage injection, I find it can improve the DC bus voltage utilization. According to the proposed six-phase induction motor SVPWM control strategy, the third harmonic injection is realized in six-phase induction motor.According to the relevant requirements of the project, the hardware circuit of six-phase induction motor control system and the experimental platform are designed. The control system includes inverter module, detection module and control module. The inverter module is the major part of the power conversion, including the inverter topology circuit, drive circuit and multiple output isolated power supply. The detection module can detect each parameter in the motor running, including the motor output phase current and DC bus voltage detection, as well as the encoder detection circuit to detect the speed of motor. The control system is the core of the whole board to complete the control, the main control chip includes DSP and FPGA, which the DSP is for testing the parameter and realize SVPWM algorithm, and FPGA is for SVPWM waveform generation. In addition, the control system also includes a communication circuit and the control panel which are used to control the system parameter settings.Finally, this thesis debugs the various parts of the circuit, and tests the multiple isolated power supply, IGBT driver circuits, current detect circuits respectively, and then the whole system is assembled. According to the six-phase induction motor SVPWM control strategy, this thesis writes a column block diagram of its program implementation, and writes the program according to the block diagram. The six-phase induction motor control system platform is used to verify the control strategy, the SVPWM control strategy based on the space decoupling and the novel six-phase induction motor control strategies were tested, and have a comparison. The six-phase induction motor were injected into the 10% and 20% third harmonic, by detecting the output current and the harmonic content, the relationship between each other is analyzed. In the end, a conclusion and some deficiencies and improvements are pointed out.