Method and system for controlling a brushless electric motor for optimal commutation over a wide speed range

摘要

A method and system is provided for controlling the operation of a brushless electric motor of the type having at least two phase windings, each of the phase windings being connected in series with a respective switch to form a respective circuit branch between the terminals of a constant voltage source thereby forming a plurality of said circuit branches in parallel to each other. A plurality of signals, each signal indicative of the electromotive force developed in a respective one of the phase windings during operation of the motor, is generated and compared with a predetermined reference value so as to generate synchronization logic signal. A control signal indicative of the angular rotor position of the motor is generated using the synchronization signal and compared with a first and a second reference signal for generating respective processing signals for controlling the current flow in each said respective circuit branch. The reference signals may be varied so as to modify the time of initiating the flow of current and ceasing the flow of current in the respective phases.