Circuit and method for speed monitoring of an electric motor

摘要

A method for determining a phase angle between voltage applied to a winding of the electric motor and an electric current flowing through the winding may include receiving a signal from the electric motor, including a value of a voltage applied to a winding of the electric motor. The method may also include determining a value of an electric current flowing through the winding and determining a phase angle between the voltage applied to the winding and the electric current flowing through the winding. The method may also include determining a speed or a stall state of the electric motor.

主权项

1. A circuit for monitoring of an electric motor, wherein the circuit comprises:
a power control circuit including a transistor with a transistor output, the transistor output configured to apply a voltage to a winding input of a winding of the electric motor, and the transistor configured to operate in a free-wheeling mode to cause the winding input to receive an electric current traversing the winding to provide a free-wheeling current circle through the winding; a circuit for receiving a signal from the power control circuit, wherein the signal indicates a value of a voltage applied to the winding input of the winding of the electric motor by the power control circuit; a circuit for receiving a value of the electric current traversing the winding, wherein the value of the electric current is determined from an electric coupling to the winding output; a circuit for determining a phase angle between the voltage applied to the winding input of the winding and the value of the electric current traversing the winding; and a circuit for outputting and evaluating the phase angle.