The present invention provides an inverter controller comprising a drive circuit that generates a plurality of switch drive signals for inverter applications. In some exemplary embodiments, the drive circuit operates by reversing the command level of an error signal. In other embodiments, the drive circuit operates by using a half period of a sawtooth signal. In still other embodiments, the drive circuit operates by using a double period opposite shifting pulses method. The present invention also provides a PWM signal generator circuit that generates periodic PWM switch drive signals symmetrical to the minimum or maximum of a sawtooth waveform.