Sensorless Control for Unsymmetrical Bistable Multimagnetic Circuit Permanent Magnet Actuator Based on High-Frequency Signal Injection and High-Pass Filter Circuit

In this article, a sensorless control method based on signal injection and a high-pass filter (HPF) circuit is presented to control the unsymmetrical bistable multimagnetic circuit permanent magnetic actuator. In this method, a high-frequency sinusoidal signal was indirectly injected into the idle phase via a HPF circuit, and the peak of the high-frequency capacitance current was measured, which was used to calculate the idle phase inductance. Thereafter, the mover position was calculated by the one-to-one relationship between the idle phase inductance and the mover position. Combined with the HPF circuit and the proposed average current peak algorithm, the influences of back-EMF and coil resistance were eliminated. The magnetic saturation effects can also be ignored in the proposed strategy. The estimated noise, caused by measurement noise and signal distortion, was filtered using a simple mathematical filter. The flexibility and accuracy of the presented strategy were verified by simulation and experimental investigation.