Commutation driving circuit of ring winding permanent magnet brushless DC motor

The invention provides a commutation driving circuit of a ring winding permanent magnet brushless DC motor. A power switch in the next state is conducted and a power switch in the previous state is disconnected simultaneously, or the two power switches are simultaneously conducted within a quite short period of time; diodes provide a freewheeling path in commutation; commutation windings quickly change direction under the effect of DC side voltage; and the commutation moment is the moment when the induced electromotive force of the windings is zero, and then the output torque of the motor is the maximum output torque. The commutation driving circuit is high in commutation speed and suitable for the situations of relatively high frequency of commutation, such as a multipolar motor or a high-speed motor.