电动汽车双向阻抗源逆变器控制系统设计

Control System of Bi-directional Z-source Inverter for Electrical Vehicles

分析了双向功率流阻抗源逆变器系统工作原理、脉冲调制方式。采用开关信号流图方法建立了统一的控制系统模型,从稳态直流模型推导出系统额定工作点,从动态小信号模型推导出系统传递函数。阻抗源逆变器控制系统是含有二维参数的非线性系统,对相互关联的2个控制变量(直通占空比D和调制系数M)进行动态解耦,对解耦系统设计了电压电流双环控制器以提高系统的动态性能和稳定程度,基于伯德图分析了控制系统的稳定性和动态特性。研制了一台55kVA双向功率流阻抗源逆变器,实验结果表明,系统具有优良性能,可以有效应用于电动汽车和可再生能源发电系统等领域。

The topology operating principle and Pulse Width Modulation strategy of bi-directional Z-source inverter were analyzed. Based on the switching signal flow graph method, the unified model of control system was developed. The rated operating point was derived from the steady model, and the transfer functions were derived from the dynamic model. Due to the presence of two control variables D and M, the control system of Z-source inverter is very nonlinear. First, the control variables were decoupled according to the dynamic related method. Second, a dual closed loop controller was proposed to improve the stability and dynamic performance. In addition, the system stability and dynamic performance were analyzed thoroughly based on the BODE plot. A prototype of a 55 kVA hi-directional Z-source inverter is designed to verify the principle and demonstrate the performance of the proposed topology.