Research On IPM Machine And Its Control Strategy Of Drive System

Interior permanent magnet synchronous motors (IPMSM) have been widely used in hybrid electric vehicle, wind power generation, ships and aerospace because of high efficiency, high power density, high output torque, well dynamic response, wide speed range. Because of serious magnetic saturation of IPMSM, the parameters are nonlinear and result in reduction of control performance. Therefore, the research on parameters of IPMSM and control strategies is important to improve performance of control system and has been research focus at home and abroad.The paper analyzes the magnetic saturation effect on parameters variation of IPMSM, and the nonlinear parameters influence precision of motor output characteristic in control system. In the constant torque range, this makes torque output capacity reduction and the terminal voltage of motor can not follow the supplied voltage in practical. In the constant power range, this makes reduction of performance caused by the saturation of voltage controller. In order to overcome performance reduction caused by inaccurate parameters, the on-line estimation model is established and this model can accurately identify nonlinear inductance parameters of IPMSM under different conditions. Then, the identified parameters are used in current control strategies and decoupling control, which makes IPMSM model linearization, realizes the current response rapidly and adjustment without static error, and improves the performance of the control system entirely depending on accuracy of parameters. Finally, we establish three IPMSM control system models. One is without magnetic saturation effect, the others use nonlinear interpolation and on-line parameter estimation to compensate saturation effect respectively. The simulation results have indicated that control system using on-line parameter estimation model to compensate saturation effect realizes smooth transition from constant torque range to constant power range, removes the system instability caused by saturated voltage controller to make terminal voltage follow given one, extends speed range in constant power range, increases the output capability of torque and improves the following-up performance effectively, robustness and the control accuracy.