Study On Permanent Magnet Synchronous Motor Drive In Hybrid Electric Vehicle Application

This dissertation is devoted to the study on permanent magnet synchronous motor (PMSM) drive system for hybrid electric vehicle (HEV) application. A PM traction motor used in HEV is developed, and it's rated torque is 291.5N·m, rated power is 55kW and peak power is 90kW. In order to improve drive efficiency, reduce the current distortion, expand the scope of field-weaking, speed up the dynamic response rate and enhance the robustness of the drive system, the drive system that improved the vector control strategy has been establishd, in the condition of a certain inverter. Whether in constant torque region, or in constant power region, the proposed drive system can achieve the expected operational performance.The current control strategy in constant torque region and the field weakening control strategy in constant power region are analyzed. An algorithm based on operation times (T₀) of zero voltage space vector is presented. The d-axis current (i_d) can be derived from the PI controller, whose inputs are T₀ and one constant T₀^*. The proposed strategy can achieve fast dynamic control as well as parameter insensitivity in the field-weakening region. Otherwise, it can also reduce the current amplitude of stator compared with the existing method that simply relies on its own ability of the PI controller to reach the final state.In general, Voltage distortion is existed between the reference and the actual output voltages in a pulse-width-modulated voltage-source inverter. This distortion is dead-time effects, which caused by the dead-time setting and non-ideal switching characteristics of power devices. A novel dynamic dead-time compensation for PMSM drive is presented based on the detailed analysis of the error voltage vector; besides, the second compensation is implemented to the voltage vector error caused by the changes of the running conditions and parameters of PM traction motor. Thus, it can improve the perfomance of the drive system effectively.Loss Model is analyzed in detail, sequentially, d-axis component of stator current can be achieved in any constant speed and torque operating point; and optimized through the gradient search technique and the Golden Section technique. In view of the operation characters of PMSM for EV application, this efficiency-optimization control strategy is presented to meet the demand of rapidity after analyzing the defect of efficiency-optimization control strategy of PMSM system with minimum input power in ordinary application. At the same time, the torque current feedforward is used to reduce the torque fluctuations. In addition, rapid response to the dynamic stator current distribution is adopted to get best transient response.The speed controller based on fuzzy neural networks is presented in this paper. Using the output of a fuzzy controller, online training is carried out to update the weights and biases of the artifical neural networks. So it can avoid the fussy calculation. The proposed scheme has the merits of quick dynamic response and robustness.It is studied that the parameters of PM motor affects on the performance of field-weakening combining with control strategy of inverter. The key problems of PM traction motor design are put forward according to the run characteristic and performance of PM traction motor. Analysis of d-axis, q-axis inductance and magnet flux linkage are made to the influence on the performance of the traction motor, and the design principles of PM traction motor are presented.At last, Results of simulation and experiment are done for the proposed driver in the prototype indicate: the presented drive achieves the objectives of the issue.