Fast simulation of multistage power electronic systems with widely separated operating frequencies

This paper presents a fast and efficient way of simulating multistage power electronic circuits with different stages operating at widely separated frequencies, using the transmission-line modeling (TLM) technique. A multistage circuit can be modeled as several smaller subcircuits, which can then be simulated individually with different time steps according to their circuit time constants. Energy exchange between linked subcircuits are made possible via the use of a new TLM stub link conversion technique and improved TLM link algorithms. The proposed technique has been tested successfully in a simulation of a switched-mode power supply. Simulation results confirm that the new approach can greatly reduce the computing time of the simulation when compared with conventional TLM simulation methods. A reduction of about two-thirds of the computing time has been achieved in the simulation of a three-stage switched-mode power supply.