内嵌式永磁同步电机定子电流矢量最佳弱磁轨迹控制策略

Control Strategy of Optimal Flux-weakening Trajectory for Stator Current Vector of Interior Permanent Magnet Synchronous Motors

针对电动汽车用内嵌式永磁同步电机(IPMSM)在高温高速下永磁体可能发生不可逆退磁的问题提出一种定子电流矢量最佳弱磁轨迹控制策略首先采用等效磁路法计算气隙磁密和永磁体负载工作点校核永磁体最大退磁工作点并计算得出永磁体的退磁电流临界值然后结合内嵌式永磁同步电机弱磁控制原理得出退磁电流临界曲线据此以最大电流输出曲线、退磁电流临界曲线和最大功率输出曲线为边界提出一种最佳弱磁轨迹仿真结果证明了该控制策略的正确性和可行性并在电流限制范围内极大提高了电机调速范围保证了大扭矩、高功率的输出改善了电机的动态和稳态性能.

A control strategy of optimal flux-weakening trajectory for the stator current vector was put forward to solve the problem that the interior permanent magnet synchronous motor (IPMSM) for electric vehicles may be irreversibly demagnetized at high temperature and high speed. First,the equivalent magnetic circuit method was used to calculate the air-gap flux density and load working point of permanent magnet,and then the maximal demagnetizing working point of permanent magnet was checked,from which the demagnetizing critical current of permanent magnet was calculated;Second,the critical current was combined with the principle of flux-weakening control of the IPMSM to work out the critical curve of demagnetization current;Then an optimal flux-weakening trajectory was proposed with its boundary composed of the maximum current output curve,the critical curve of demagnetization current and the maximum power output curve;The simulation results proved that the control strategy is correct and feasible,and greatly extends the speed range of motors within a predetermined current range,thus ensuring the output of large torque and high power and improving the dynamic and steady-state performance of motors.