Averaging methods for electrical-thermal converter models

Simulating the transient thermal response and calculating the steady-state operating temperature of switching converter models is time consuming in a system with large thermal time constants. In this paper, two averaging techniques for speeding up the simulation of switching electrical-thermal converter models are presented and compared. With the loss averaging method, the switching device losses are averaged before being applied to a resistive-only thermal network. The steady-state operating point can then be rapidly simulated. With the circuit averaging method, an averaged converter model is used with averaged lookup tables, allowing the device losses to be calculated directly from the average device currents. This method permits a rapid transient simulation. In this paper, both methods are described in detail. An example inverter model, developed using PLECS, is simulated to demonstrate the operation and performance of the two methods.