Modeling And Control Strategy Of Hybrid Excitation Synchronous Motor For Vehicle

In the field of new energy vehicles,as a new type of drive motor,hybrid excitation synchronous motor combines the advantages of high efficiency of permanent magnet synchronous motor and adjustable air gap flux of electric excitation synchronous motor,which solves the problem of difficult magnetic adjustment of permanent magnet synchronous motor.Therefore,an asymmetric interleaved hybrid excitation synchronous motor is taken as the research object,and its control technology is made an in-depth study on.First of all,in order to reduce the difficulty of modeling its mathematical model,the influence of some nonlinear factors can be ignored,such as temperature,high-order harmonics,magnetic material saturation and so on.the mathematical model is simplified,and the establishment of the mathematical model in the two-phase rotating dq coordinate system is completed.Then,according to the vector control and partition control strategy,the vector control system of hybrid excitation synchronous motor is established,and the high and low speed control strategy is studied.In order to improve the low-speed load and anti-interference ability of the system,a sliding mode speed controller is designed under the low-speed operation condition of the hybrid excitation synchronous motor.However,the inherent chattering phenomenon of the sliding mode control will affect the stability of the system.To solve this problem,a low-speed current control strategy based on load torque sliding mode observer is proposed.In this strategy,the torque value observed by the load torque sliding mode observer is used as the q-axis current feed-forward compensation,and the change rate of the difference between the load torque and the permanent magnet torque is used as the given input of the excitation current;in the high-speed operation condition of the hybrid excitation synchronous motor,a fuzzy PI speed controller is designed,and a high-speed current control strategy based on voltage feedback is proposed to broaden the speed range of the motor;The feasibility of high and low speed control strategy is verified by Matlab/Simulink simulation.Finally,a hardware-in-the-loop simulation test system composed of NI’s real-time simulator and an actual controller with DSP28335 as the core is selected to carry out further simulation tests on some functions of the control strategy to verify the effectiveness of the control strategy.The experimental results show that the low and high speed control strategy realizes the smooth speed regulation of the hybrid excitation synchronous motor,improves the anti disturbance ability of the hybrid excitation synchronous motor,has good static and dynamic performance,and meets the requirements of its operation in different working conditions.