Improving the Performance of Direct Power Control Using Duty Cycle Optimization

Direct power control (DPC) has been proposed as an effective control method for pulsewidth modulated (PWM) converters. The recent development focuses on the integration of the model predictive (MP) control and DPC to obtain better steady-state performance. In most MP-DPCs, duty cycle optimization (DCO) is a common technique to achieve the power error minimization. However, the periodic occurrence of a duty cycle larger than one (D > 1) deteriorates the performance of the PWM converter by inducing current spikes and power surges. To address this problem, this paper conducts an in-depth examination on the “D > 1” case common in MP-DPC using DCO. It is found the “D > 1” case is caused by the wrong control action of the active power in the starting period of each sector. Furthermore, a new table containing an additional pre-calculated interval in every sector is developed to eradicate the “D > 1” case and its associated power quality issues. Both simulation and experimental results are provided to demonstrate the effectiveness of the new table.