一种降低无刷直流电机EPS系统损耗的PWM控制策略

无刷直流电机电动助力转向(Electric Power Steering, EPS)系统由车载蓄电池供电,采用由MOSFET构成的三相电压型逆变器驱动.为了降低无刷直流电机EPS系统的损耗,本文提出了一种新颖的脉冲宽度调制(Pulse Width Modulation, PWM)控制策略,即无论EPS系统处于助力状态、回正状态还是阻尼状态,当检测到某一个MOSFET反并联的续流二极管导通时,就给该MOSFET的门极施加驱动信号,以此来降低续流二极管的导通压降和导通损耗,减少其发热,提高逆变器的工作效率.实验证明,本文提出的PWM控制策略在降低EPS系统损耗的同时可以对汽车转向过程的各个环节进行有效的控制,且该方法实现简单,具有较强的实用性.

Low Loss PWM Control Strategy for EPS System With BLDC Motors

The electric power steering (EPS) system with BLDC motors, which are driven by a voltage source inverter with metal oxide semiconductor field effect transistors (MOSFETs), is fed by battery. This paper presents a novel PWM control strategy, which can significantly reduce the power loss of EPS system. While the anti-parallel diode is freewheeling, a drive signal is applied to the corresponding MOSFET to reduce the voltage drop of the anti-parallel diode, and thereby the conduction loss and head dissipation are reduced dramatically. Experimental results show that the proposed low loss control strategy is not only effective for EPS controlling, but also easier to realize, so it has strong practicality.