多相开关磁阻电机中点电压有源调节功率变换器的研究

Research on the Mid-point Voltage Actively Adjusted Power Converter of Multi-phase Switched Reluctance Motor

多相开关磁阻电机功率变换器具有功率器件和出线数多的缺点,而采用常见的较少开关管的变换器,又存在相间不独立、控制策略受限、电机输出转矩下降的问题。对此,本文提出了一种中点电压有源调节功率变换器,通过在无中点电容裂相式功率变换器的中点引入两个开关管,采用PWM控制对绕组星型连接的中点进行有源调节,从而达到与不对称半桥功率变换器等效的控制效果,提高了输出转矩和故障运行能力,降低了公用开关管的电流应力,在降低成本的同时具有相间独立、控制灵活的优点。本文以一台24/18结构的四相样机为控制对象,对新型变换器的不同控制方式以及不同功率变换器的电机作用效果进行了仿真分析,最后通过实验验证了新型变换器的可行性。

In the power converter of Multi-phase Switched Reluctance Motor, the number of the power devices and lines out from the motor is high. While if converters with fewer switches used, the problems like phases coupling, limited control strategy, and output torque decrease will be caused. To solve these, the mid-point voltage actively adjusted power converter was proposed in this paper. In the base of the split phase converter without mid-point capacitor, two switches are connected to the mid-point and PWM control was adopted to adjust the mid-point voltage. The new converter is equivalent to the asymmetric half bridge converter, improving the output torque, fault operation ability and lowering the current stress of shared switches. It has advantages of little cost, separate phases, and flexible control. In this paper, a 24/18 four phase Switched Reluctance Motor was used as the application object. And the simulation and analysis under different control strategy and types of converters were also carried on. Finally, the experiment results verify the effect of the new converter.