低压电动车开关磁阻电机隔离驱动技术

在传统的低压电动车开关磁阻电机(SRM)驱动系统的设计中,优先考虑的问题是系统的体积和成本。通常在MOSFET驱动电路、相电流和母线电压采样电路设计中直接忽略了数字地和功率地的隔离问题,使得整个驱动系统的可靠性大打折扣。在保持传统的非隔离驱动系统中驱动电路和电阻采样电路的基础上,提出采用高速光耦实现PWM控制信号与MOSFET驱动信号的隔离,采用线性光耦实现相电流和母线电压采样信号与控制器AD采样信号之间的隔离。该方式可以在尽量不增加系统体积和成本的情况下,实现数字地和功率地隔离,从而进一步提升低压电动车SRM驱动系统的可靠性,具有广阔的应用前景。

Isolated Driving Technique for LowVoltage Electric VehicleSwitched Reluctance Motor Drives

In the design process of traditional lowvoltage electric vehicle switched reluctance motor (SRM) drive system, the first consideration was the volume and cost of the system. Generally, the isolation of the digital ground and the power ground was always neglected in the design of the MOSFET driving circuits and the phase current and bus voltage sampling circuits, which deteriorated the reliability greatly in the driving system. Based on the traditional drive circuit and resistance sampling circuit in nonisolated drive system, a highspeed optocoupler was proposed to isolate the PWM control signal from the MOSFET drive signal, and a linear optocoupler was used to isolate the phase current sampling signal and bus voltage sampling signal from the AD sampling signal of the controller. This method could achieve the isolation of digital ground and power ground without increasing too much the system size and cost, and thus further improve the reliability of lowvoltage electric vehicle SRM drive system. The proposed method had important application prospects.