Abstract: An AC-DC power converter has a power factor correction stage that receives grid power and produces DC bus power. A DC-DC converter stage receives the DC bus power and produces a DC output power. Energy storage is provided by a larger capacitance value first capacitor and a smaller capacitance value second capacitor coupled in series across the DC bus power with a switching device coupled in parallel with the smaller second capacitor. During converter start-up, the switching device is turned off and inrush current is controlled by transferring energy from the second capacitor to the first capacitor. During operation the switching device is turned on and the first capacitor provides energy storage for the DC bus power. When grid power is disconnected, hold-up time is extended by turning the switching device off and transferring energy from the first capacitor to the second capacitor.

Abstract: A direct power AC/DC conversion apparatus employs a dual branch topology. A first branch includes a first AHB switching network configured to receive an AC grid power and produce an AC power, coupled through a series resonant impedance to a first primary winding of a transformer. The first switching network includes two bi-directional switches coupled in series where each bi-directional switch includes two switching devices coupled in series in opposite polarity. A secondary winding of the transformer is coupled through an SR switching device to an output DC power. A second branch includes a diode bridge, configured to receive the AC grid power and produce a DC power, coupled to a second AHB switching network. The second AHB switching network is coupled through a second series resonant impedance to a second primary winding of the transformer. Each of the first and second branches are operated alternately and independently.

Abstract: A control method for a hybrid three-port DC-DC power converter combining a dual active bridge converter and a dual active bridge series resonant converter topology. The controller includes a first control loop to regulate power flow between the first port and the second port and a second control loop to regulate power flow between the second port and the third port. The first control loop employs a three-mode control methodology to regulate power flow through the dual active bridge converter between the first port and the second port. The second control loop is configured with a lower bandwidth than the first control loop and regulates power flow through the dual active bridge series resonant converter between the second port and the third port.