Magnetic Field Analysis and Control Strategy of Permanent Magnet Actuator for Low Voltage Vacuum Circuit Breaker

Permanent magnet actuator has such advantages as free-maintenance and high reliability. In this paper, a new type of permanent magnet actuator used for lower voltage circuit breaker is analyzed based on 3-D finite element method. Typical flux density distributions are computed with different currents. Two control strategies, open-loop control and closed-loop control, for the permanent magnet actuator to make or break breaker is presented in detail. The experimental results of two control strategies show that closed-loop control can achieve good performance than open-loop control.