A new method of grounding detection for rotor windings of brushless synchronous motor

Aiming at the special structure of brushless synchronous motor, a new method of grounding detection for rotor windings was presented, namely Active Resistance Bridge. Its advantages are as follow: no dead-zone, no impact of excitation voltage on grounding detection sensitivity, and so on. The hardware and software system of grounding detection are designed, the simulative and experimental results show they are correct. In addition, the impact of three-phase sudden short-circuit of grid on grounding detection is also considered, the simulative results show the malfunction doesn´t occur, which shows the grounding detection system is highly reliable.