基于直接转矩控制的超低速高精度正弦波交流伺服系统

A Super-Low-Speed High-Precision Servo System for Enabling Antenna to Track Space Object Continuously

提出并阐述了基于外转子稀土永磁正弦波无槽无刷力矩电机直接转矩控制的数字式超低速高精度伺服系统的总体方案、工作原理、控制策略和功能实现。实测结果表明,可实现高精度和稳定的超低速运行特性。

MAPS(Modular Antenna Pointing System)is a super-low-speed high-precision servo system used by Explorer Platform (EP) satellite to maintain continuous digital communication with TDRS (Tracking and Data Relay Satellite). The super-low-speed servo system we designed is about the same as MAPS in super low speed but is an order of magnitude better than MAPS in tracking precision. First we analyze theoretically direct torque control of slotless brushless sinusoidal torque motor, which contains an REPM (rare earth permanent magnet) external rotor. In designing the servo system, after repeated rethinking, we finally decided on using direct-driving-type driving circuit, which, in our opinion, is key to attaining high precision. In order to ensure the reliability of the servo system, we used a MOSFET switch in circuit breaker. Feedback channel is the key channel of the servo system. In our design, we paid special attention to processing detected position signals in the feedback channel so as to convert them into digital signals of high precision. Test results of the servo system designed and developed by us show preliminarily that it is of high precision ( ±0.05°) and excellent super low speed stability.