Analytical Modeling and Controller Design of a Modular Series Parallel Resonant Converter System for a Solid State 2.88-MW/115-kV Long Pulse Modulator

In this paper, two control strategies for voltage balancing in a modular serial parallel resonant converter modulator system, which is used in a high-voltage-pulsed power application, are presented and verified by simulations and measurements. The system is based on two series parallel resonant converter modules, forming an input series output parallel stack. To obtain the given output voltage pulse of 115 kV, nine of these input series output parallel stacks are connected in parallel at the input and in series at the output, forming an input parallel output series system. A robust input voltage balancing by an auxiliary circuit and an output voltage balancing by control is introduced and proven by measurements. In addition, an alternative approach, where the input and output voltage balancing is achieved purely by control, is given and verified by simulations. For designing the control of this system, a large and a small signal model is derived and the influence of component tolerances is investigated.