Phase Current Regulation in BLDC Motors

Abstract

A method is provided for determining a phase current direction and a zero-crossing moment of the phase current in a sinusoidally controlled brushless direct current motor. The brushless direct current motor comprises a coil per phase and the phase of the brushless direct current motor is driven by a half bridge driver. The half bridge driver comprises a high side field effect transistor and a low side field effect transistor. The method comprising the following steps: measuring the drain source voltage over the high side field effect transistor and low side field effect transistor, and determining the zero crossing moment of the phase current by determining the current direction based on the measured drain source voltages and by determining the moment the current changes direction.

Dependencies are inferred from the claim text.