Patent ID: 7688605

Claim:
A direct current (DC) to alternating current (AC) pulse width modulation (PWM) power inverter including a set of switches and a control logic operating said set of switches based on a control signal and a reference signal, the improvement comprising: said control signal comprising a sine wave having a frequency equal to the desired output of said power inverter; and said reference signal comprising a triangular wave, said wave having irregular periodicity, wherein, said irregular periodicity comprises a sequence of a predetermined number (n) of juxtaposed different periods, said sequence exhibiting a uniform probability distribution with mean at a target period (T target ), said n different periods differ from one another by a multiple of a fixed time value (Δt), and an upper bound period (T upper ) and a lower bound period (T lower ) of the n different periods satisfy the following respective equations: T lower =T target −( n×Δt )/2 and T upper =T lower +( n×Δt ).