A DSP-Based Vector Control System Of Multiphase Permanent Magnet Synchronous Motor

The performance of AC variable speed drive system has been improved greatly since field-oriented control is applie'd, and the reliability of drive system composed of multiphase Permanent Magnet Synchronous Motor (PMSM) is enhanced. After the field-oriented control of three-phase PMSM drive system is introduced in brief, a mathematical model of multiphase PMSM, taking a six-phase PMSM with a dual-star winding for example, is derived by coordinates transformation. Additionally, taking phase redundancy into account, the compensation control of multiphase PMSM is illustrated emphatically when one (or more than one) leg of the motor or the corresponding inverter is lost, and two compensation schemes are presented. One is based on producing the same magnetic motive force under fault condition as that under normal condition, and the other is novel field-oriented control based on the improved rotary frame transformation adopted. The simulation results of both the multiphase PMSM and three-phase PMSM show that the former performance is much better than the later one, and that the multiphase PMSM under fault condition operates as well as under normal condition when compensation control is applied. So the conclusion is drawn that the performance of multiphase PMSM variable speed driver system gains an advantage over the counterpart of three-phase PMSM and the former reliability is much better than the later one.Moreover, after the principle of fuzzy control is illustrated, a dual-model control scheme based on PI (Proportional Integral)+EFLC (Enhanced Fuzzy Logic Controller) is also brought forward, so that the disadvantage of the PI controller will be avoided. The simulation results show that the scheme is desirable.A hardware based DSP (Digital Signal Processor) and CPLD (Complex Programmable Logic Device) for multiphase PMSM variable speed drive system is established, and the corresponding software design is also presented in the paper.