An isolated DC-DC converter with high-output-voltage for a TWTA

This paper reports on a theoretical and experimental study of an isolated parallel resonant DC-DC converter, with high output-voltage, to bias a high-power TWTA (Traveling-Wave Tube Amplifier). The converter features a single stage, it is based on a Full Bridge structure, it is isolated, it utilizes the intrinsic parameters of transformer and it employs a Phase-shifted Carrier (PSC) Pulsewidth Modulation (PWM) to regulate its output voltage. The proposed converter contain capacitive-input output filters, therefore theirs outputs have the characteristics of a voltage source. The converter can be referred to as a Parallel Resonant Converter with Voltage Source Output (PRC-VSO). The output stage of the DC-DC converter is constructed using series-connected modules, which allows lower voltage devices to be employed. The proposed converter was analyzed for static gains lower than one, PSC-PWM and Continuous Conduction Mode (CCM), and the structure was experimentally verified on a 2.5 kW prototype, fed into 300V, which was used in the biasing of a TWT with voltages of 1.3 kV in the focusing electrode, 3.42 kV in collector 1, 4.94 kV in collector 2 and 9.5 kV in the cathode.