The Research On Drive And Fault-tolerant Control System Of Five-phase PMSM

With natural resource decreasing largely, human pays more attention to energy conservation. And compared with traditional three-phase machine, five-phase permanent magnet machine is with more advantages, such as high reliability, transmission of high power under low voltage, fault-tolerance and so on. In this paper, model of five-phase permanent magnet machine control system has been built, then SVPWM algorithm and vector control system based on five-phase five-leg inverter in normal and one-phase open situation have been studied. Besides, one-phase open fault-tolerance algorithm based on five-phase six-leg inverter has been analyzed. Finally, through the platform for five-phase machine control system, correlative experiments have been taken.Firstly, mathematical model of five-phase machine has been analyzed. According to three-phase coordinates transformation theory, the extending one for five-phase machine can be gotten, then mathematical model of five-phase machine with the direct-axis and quadrature-axis decoupled has been built. Moreover, machine control system in form of transfer function has been built to analyze the design principle of speed and current PI regulators. These theories are for building the machine control system in Simulink.Secondly, While machine is in normal situation, five-phase six-leg inverter acts as five-phase five-leg inverter because of zero current at neutral point. Therefore, the 0di = vector control is adopted. Then SVPWM algorithm for five-phase five-leg inverter has been studied in detail. Both NTV-SVPWM and NFV-SVPWM algorithm have been analyzed and simulated correctly in Simulink. And over-modulation of NFV-SVPWM has been studied, then optimized and un-optimized NFV-SVPWM have been compared to conclude that optimized NFV-SVPWM can eliminate low-order harmonics.Thirdly, fault-tolerance for one-phase open has been analyzed. Based on five-phase five-leg inverter, current hysteresis of equal phase current amplitude has been simulated correctly. To decrease the complexity of this algorithm, vector control based on five-phase six-leg inverter for one-phase open has been adopted, which can decouple each phase and keep machine rotate steady after open fault. Moreover, as for unset switching frequency and large torque ripple caused by current hysteresis based on five-phase five-leg inverter, current hysteresis based on five-phase six-leg inverter has been adopted and simulated in Simulink.Finally, through platform based on DSP F28M36, correlative experiments have been taken on two kinds of five-phase five-leg inverter SVPWM algorithm, and optimized and un-optimized NFV-SVPWM algorithm experiment conclusion is in accordance with simulation. Besides, experiment for machine under current closed-loop control has been taken correctly.