A constantly sampled current controller with switch status dependent inner bound

In this paper, a constantly sampled current-controlled pulsewidth-modulation (PWM) strategy is proposed such that the controlled current can follow the command within a specified error bound to guarantee the desired good power quality. According to different previous switch statuses, a different inner bound is proposed for current error comparison to add the zero-mode control at the proper time to further reduce the switching frequency. Moreover, an analytic expression of the upper bound of the constant sampling period for the current controller to guarantee the desired performance is derived and some design criteria are given for proper coordination among the circuit parameters. Finally, some simulation and experimental results are given to demonstrate the validity of the proposed current-controlled PWM scheme.