Dead beat control of three phase PWM inverter

Abstract

This paper proposes new method of high performance current and/or voltage control of three phase PWM inverter, especially suitable for high speed switching devices such as Transistor and BIMOS. As the controller for calculation of the dead beat algorism, a high speed digital controller, such as the digital signal processor is assumed. Following new methods are successfully adopted and combined to realize high quality. (1) Three phase inverter current and voltage are transformed to synchronizing d-q-0 frame, and discretized equations of current and voltage are derived, which clearly reveal coupling of voltage and current of inverter on d-q frame. (2) Using above discretized equation of main circuit, algorism of Dead Beat control with compensation for decoupling is developed. (3) New method for compensation of computing time delay and full utilization of sampling interval for inverter output pulse width is developed, which utilizes 2nd order load current prediction and discretization with twice time of sampling period. (4) Double Dead Beat control system is developed for sinusoidal output voltage inverter, which has high speed current minor loop to constrain inverter current within safety limit. Validity of these techniques has been confirmed by simulation using a hybrid computer.