State Space Averaged Modeling of the Bridge type Forward Watkins Johnson DC to DC Converter

Abstract

In this work the averaged state space model of the bridge type Forward Watkins Johnson Converter (FWJC) is developed and simulated. The FWJC is a DC to DC converter that can deliver a DC output voltage with positive or negative polarity controllable by the duty cycle. If the duty cycle is maintained between 1.0 and 0.5 the FWJC enters into the positive output buck mode of operation. With duty cycles in the range between 0.0 and 0.5 the FWJC enters into the negative output buck boost mode of operation. The voltage gain of the FWJC, over the duty cycle scale of 0.0 to 1.0, ranges between -? and +1 respectively with zero voltage gain when the duty cycle is 0.5. Unfortunately, a detailed classical analysis of the bridge type FWJC is not found in the literature. In this work, the averaged state space model of the FWJC is developed from the fundamental principles. The results of simulations of the state space averaged model have been compared with the results of simulations of the circuit modeling, both developed in the MATLAB SIMULINK environment.

Keywords- Watkins Johnson Bridge type Converter, Voltage Gain derivation of DC to DC converters, State Space Averaged Model, Circuit Model Simulation in MATLAB SIMULINK,