Title: Audible noise reduction for single current shunt platform
Application Number: 200610163565 Application Date: 2006.10.26
Publication Number: 1976215 Publication Date: 2007.06.06
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02P27/04;H02P27/06;H02P23/00;H02P23/14
Applicant(s) Name: Int Rectifier Corp. Address:
Inventor(s) Name: Ho Eddy Ying Yin
Attorney & Agent: chengwei
Abstract:
    A method and system 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, and for controlling the motor, which forms a command voltage vector according to a space vector modulation arrangement for controlling the motor; measures the DC bus current; and determines across part area 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, a current sampling scheduler applies 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; and reduces the application of said minimum pulse width constraint to less than once per PWM cycle imposed by the PWM inverter motor drive system, thereby allowing motor phase current reconstruction with reduced audible motor noise. The current sampling scheduler synchronously samples said measured motor phase current to reduce errors; reduces a bandwidth of said motor controller during said inverter switching state; and is adjustable in response to motor speed for setting the number of said minimum pulse width constraints per PWM cycle.
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