DC Plasma Power Supply with Multi-port Solid State Transformer and Inverse Model Predictive Control

This paper proposes a DC plasma power supply topology with systematic design and robust voltage control approach. The proposed topology consists of a three-port solid-state transformer (SST), comprising one port for the input source, a second port to deliver high voltage (HV) required for plasma ignition, and a third port for supplying a constant low voltage (LV) for sustained plasma reactor operation. A comprehensive design methodology is presented to determine all passive elements, including the resonant tank components and transformer's turns ratios. Moreover, a seamless transition algorithm between ignition and operation modes is presented. To achieve micro-scale dynamic response, an inverse model predictive control (IMPC) strategy is employed to identify the necessary switching frequency in feedforward fashion. In parallel, a PI controller is used to eliminate the deviation and steady state error of the output voltage and ensure asymptotic error convergence, even in the presence of parameter uncertainties. The proposed circuit, seamless transition algorithm, and the control technique are implemented on a lab-scale test-bed with voltage range between 0-1200 V.