Improved Digital Peak Voltage Predictive Control for Switching DC–DC Converters

Abstract

A digital peak voltage (DPV) predictive control for switching dc-dc converters is proposed and studied in this paper. With the predictive control technique, the duty ratio in each switching cycle is usually calculated and predicted based on the status in the previous switching cycles. Therefore, at least a one-switching-cycle time delay usually exists in predictivPe control, which significantly degrades the control performance of digital controlled switching dc-dc converters. To eliminate this time delay and to improve the control performance, an improved DPV (IDPV) predictive control technique is then proposed and studied. The control laws of DPV and IDPV with different pulsewidth modulations are derived, and their stabilities are analyzed. A simple digital slope compensation method is proposed to eliminate the subharmonic oscillation of DPV and IDPV control laws. The steady-state and transient performances of DPV and IDPV controlled buck converters are investigated by simulation and experiment. The comparison studies among DPV, IDPV, and digital peak current (DPC) control show that the transient performances of IDPV and DPV are much better than that of DPC and that IDPV is better than DPV.