Control Strategy of Active Storage Unit in Pulsed Load AC Input System to Reduce DC Bus Capacitance

To reduce DC bus capacitance in single-phase input and pulsed load power supply (SIPLPS), an active storage unit (ASU) is employed to buffer the unbalanced power on the DC bus of power factor correction (PFC) converter. According to the analysis of harmonic current on DC bus, the control strategy of ASU is proposed in this paper. The ASU operates as a current source in which input current is controlled to track the second harmonic current of PFC converter and the alternating current component of pulsed load current. For achieve ASU which can decouple double-shape and double-frequency power, a Buck/Boost converter operating in discontinue current mode (DCM) is adopted, because of benefits in fast tracking response and small inductor volume. The design method of the DCM Buck/Boost converter with beat-frequency input current reference is also proposed. An electrolytic capacitor-less SIPLPS prototype with beat-frequency is fabricated. The experiment results verify the proposed control strategy and design method.