Patent ID: 7348758

Claim:
A method for reducing audible motor noise in a system for reconstructing motor phase current from a DC bus current comprising current pulses on a DC bus in a PWM inverter motor drive system having a PWM cycle, and for controlling the motor, comprising: forming a command voltage vector according to a space vector modulation arrangement for controlling the motor; measuring the DC bus current on the DC bus supplying power to the inverter to reconstruct said motor phase current; determining a sector crossing region when the command voltage vector results in an inverter switching state that prevents the measuring of the DC bus current from accurately indicating motor phase current; during said inverter switching state, applying a minimum pulse width constraint to said current pulses in said DC bus current to improve reconstruction of said motor phase current based on said DC bus current; applying said minimum pulse width constraint less than once per PWM cycle during said sector crossing region, thereby allowing motor phase current reconstruction with reduced audible motor noise.