永磁同步电机无传感器控制算法切换研究

针对永磁同步电机全速域的无传感器控制，在不同的速度范围有着不同的控制策略，而保证不同速域控制策略的平滑切换是实现全速域稳定运行的前提。本文低速域采用恒电流变频（I/F）控制策略，中高速域通过改进滑模观测器准确获取转子位置，并且在高速域时采用弱磁控制使电机有更宽的调速范围。为了实现高低速域的快速平稳切换，提出了一种d,q轴电流同时变化并且保持总电流不变化的改进切换策略，使电机从开环控制直接切换至最大转矩电流比运行，切换过程平滑无冲击。仿真结果证明了本文提出的改进切换策略的可行性。

Research on Swiching Strategy of Sensorless Control Algorithm of Permanent Magnet Synchronous Motor

For sensorless control of permanent magnet synchronous motor in full speed domain, there are different control strategies in different speed ranges.And t he smooth switching of different control strategies is the premise of realizing stable operation in full speed domains. In this paper,the a constant current variable frequency control strategy is a dopted in the low speed domain.In the middle and high speed range,the rotor position is precisely obtained by improved sliding mode observer,and the flux-weaking control is applied to make the motor have a wider speed range.In order to switch smooth ly and quickly between the high and low speed domain, an improved switching strategy is proposed,in which the current of d and q axis changes simultaneously and the total current does not change,so that the motor can directly switch from the open-loop control to the max torque per ampere operation, and the switching process is smooth and non-impact.Finally,the feasibility of the proposed strategy is verified by simulation.