Research On The Fault-Tolerant Control System Of Open Winding FTFSCW-IPM

With the increasing depletion of fossil fuels and global warming, Fog and haze and other increasingly serious environmental problems, electric vehicles are widely used, the safety and reliability of the system become a very high demand. The motor electric drive system, as the core part of the car, is crucial to the reliability of the motor drive system. Motor drive system includes two aspects, namely, the drive inverter section and power section, the conventional inverter system is generally a two-level inverter as the power supply, with large THD, low DC voltage utilization, for single power switch’s open-fault and open phase fault, the system can’t operate continually in fault-tolerant mode. In order to improve the performance of the inverter, multi-level inverter system is grually applied to the motor system with small output voltage harmonic content, high DC voltage utilization, redundant fault-tolerant ability for some fault. Fault-tolerant fractional-slot concentrated winding interior permanent magnet motor (FTFSCW-IPM) with simple structure, high power density, high short circuit isolation capability, has been widely used in aerospace, electric vehicles and other fields. The open winding FTFSCW-IPM possess multi-level features, flexible operation, high reliability and more potential applications. In this paper, the open winding FTFSCW-IPM with dual-inverter control system is presented. The reliability of the drive system under different power supply is analyzed and new strategies are proposed for different operation mode. Simulation and experimental verification of the fault-tolerant control strategies are carried out. This paper provides foundation for the drive system reliability research and its application in the field of electric vehicles.The main research contents of this paper include the following aspects:1) The background and significance of research are introduced and the research of motor drive fault-tolerant control system is described. Detailed analysis of the open winding FTFSCW-IPM drive system topology and operating principle are presented, based on this, the strategies of control and PWM are analyzed, the single-power switch open fault tolerant control strategy get further research to achieve fault-tolerant operation and the balance of power under fault tolerant operation. Based on MATLAB/ Simulink platform, open winding FTFSCW-IPM drive system fed by isolated power is built, and the proposed strategy is simulated and verified.2) A fault tolerant control strategy based on decoupled svpwm is proposed under single-ami open fault in open winding drive system fed by isolated power. To suppress midpoint voltage offset, a current feedback suppression method is presented. Based on MATLAB/Simulink platform, the proposed strategies are verified through simulation.3) Circulation problems of open winding drive system fed by single supply is analyzed in detail under normal operation, and the tritional SVPWM method of circulation suppression is presented and simplified, implementation of the drive system procedures is streamlined and the same effect of conventional modulation method is achieved. Based on MATLAB/Simulink platform, the proposed strategics is verified.4) In order to increase the output capacity of the system after the open-phase fault, a simplified modulation algorithm is proposed based on the tritional fault-tolerant SVPWM. Based on MATLAB/ Simulink, open winding drive system fed by single power is built, simulation results show that the drive has a fault-tolerant system performance itself after open-phase fault, but with small voltage output, low utilization of the remaining voltage vector. The simplified SVPWM algorithm achieves fault-tolerant operation phase after failure, and maximize the use of the remaining vectors, the drive system output capability is improved under fault-tolerant operation.5) Based on dSPACE1104, an open winding drive system experimental platform is developed. The main circuit and auxiliary circuit are designed.Based the designed experimental platform, the above control methods and control strategies are carried out and experimental results verified the theoretical analysis and simulation results.