PWM frequency pattern optimization for NVH

An optimized pseudo-random period pattern can reduce audible noise in a system that includes an inverter circuit configured to provide power to an electric machine. A system can include a PWM optimization module (POM) comprising the PPP. A carrier period for a carrier signal used to provide PWM inverter drive signals can be selected in accordance with the PPP. The PPP can be expressed as an array of 200-400 elements, each element a period belonging to a finite set of 2 or more predetermined periods. A period can be selected by index from the array, and the index incremented to progress through the PPP, which can be repeated upon its completion. The PPP can be optimized to reduce audible noise while mitigating inverter losses. Modeling techniques can determine the number of array elements, the number of possible periods, and the period values that optimize the PPP.