A Novel Phase Control Strategy for Suppressing Beat Frequency Oscillations Between Parallel-Connected Boost Converters

A phase control strategy is proposed for suppressing beat frequency oscillations between parallel-connected DC-DC boost converters, where the beat frequency equals the difference between switching frequencies of converters. First, the fundamental hardware and software causes of beat frequency dynamics are analyzed, which naturally leads to a feasible control strategy to suppress the oscillations. Next, a communication independent phase detector is proposed to estimate the beat frequency oscillation phase which is also the PWM carrier phase difference between converters. Notably, the sampling distortion, typically considered harmful in the boost converter controller implementation, is creatively regarded as a phase-information carrier. On this basis, a phase regulator is designed to manipulate the beat frequency oscillation phase into a preset tolerance range. Finally, a comprehensive control framework is constructed, which can be implemented without additional hardware change. Experimental results validate the effectiveness of the proposed control strategy.