Identification method for electromagnetic torque of permanent-magnet synchronous motor

The invention discloses an identification method for an electromagnetic torque of a permanent-magnet synchronous motor. The identification method comprises the following steps of allowing a neutral point of the permanent-magnet synchronous motor and a middle point of a DC voltage source to be grounded, and allowing the voltage of the neutral point of the permanent-magnet synchronous motor to be 0; determining an end voltage of the permanent-magnet synchronous motor according to connection and disconnection states of a power tube and a fly-wheel diode during the conduction process and the follow current process of a three-phase full-bridge inverter, and subtracting the voltage of the neutral point from the end voltage to obtain a phase voltage of the permanent-magnet synchronous motor; calculating to obtain a three-phase reverse potential of the permanent-magnet synchronous motor according to the phase voltage and the phase current, obtained by detection of a current sensor, of the permanent-magnet synchronous