Single-Phase AC-DC Converter with SiC Power Pulsation Buffer for Pulse Load Applications

Single-phase ac–dc converter for low-frequency pulse load normally requires high-capacitance electrolytic capacitors, which reduces the lifetime and may cause reliability problem. To meet the challenges of voltage ripple, this article introduces a power pulsation buffer (PPB) that smooths the output voltage and provides essential pulse power to the load simultaneously. The proposed PPB is realized by a discontinuous current mode (DCM) bidirectional buck/boost converter with real-time duty-cycle calculation (RDC) and peak voltage control. The proposed control method can relieve the capacitance requirement and achieve good dynamic response. The electrolytic capacitor is replaced with the film capacitor which has better reliability. SiC devices are adopted to further reduce the inductor volume of PPB. The core-less design is also proposed to design an integrated air-core inductor for further volume deduction. To meet the DCM requirement of PPB in various operating conditions, the phase shift between the line voltage and pulse load is taken into account. An electrolytic capacitor-less prototype with 1800-W peak power is built to verify the advantages of the proposed method.