One of the reasons of the low efficiency for debugging phase-controlled circuit breaker is the lack of theoretical reference to the electromagnetic buffering position

which leads to repeated iterations in debugging process.The coil control loop is firstly analyzed in this paper for the permanent magnet mechanism.Combined with the characteristics of power switching component during the opening process we find out the parameters for controlling the electromagnetic buffer intervention position.Then the electromagnetic parameters of the permanent magnet mechanism is analyzed under the condition of unbuffered and buffered by different positions.Through simulation

the electromagnetic driving force

coil current and other parameters are obtained.In order to study the influence of electromagnetic buffer on the rebound and opening speed

the simulation results of the electromagnetic driving force were introduced into the dynamic analysis software Adams

and the characteristics was simulated.The results show that the earlier the electromagnetic buffer is intervened

the smaller the rebound and the lower the opening speed.Finally

in order to verify the correctness of the simulation results

test was carried out on the prototype of 40.5 kV three-phase phase-controlled circuit breaker.The test results are in good agreement with the simulation results.It proves that the method provides effective guidance for debugging and testing of the mechanical characteristics of the permanent magnet mechanism.