A quasi-PID controller for complex waveform generating inverters

A quasi-PID controller for complex waveform generating inverters that is derived from further analysis of the commonly used pulse width modulation (PWM) method of triangular carrier comparison is proposed in this paper. Firstly, the accurate theoretical formulas are obtained for the parameter turning of the PI controller, so as to make the normally cumbersome adjusting process much more readily. Due to the satisfactorily good performance of the quasi-PID controller, it can be either introduced into traditional inverters directly, or adopted as the initial state machine (ISM) of high accuracy intelligent-PID control inverters for the purpose of ensuring system stability and safety at start-up and also making the intelligent control algorithm operate more smoothly and effectively. Moreover, the proposal of the quasi-PID controller also presents a compelling answer to the interesting question: why do almost all the inverters adopt P or PI controller primarily but do not consider the strict PID controller? The answer is that the strict proportional, integral and derivative (PID) controller is not suitable for the PWM inverter, and only the quasi-PID controller is workable. This argument is verified in this paper.