Triangular and Trapezoidal Modulation for Dual Active Bridge DC-DC Converters with Fast Switching Semiconductors

This paper presents improved equations to operate a dual active bridge converter with the combined triangular and trapezoidal modulation. They increase the accuracy of the predicted switching times by incorporating parasitic effects such as equivalent resistance, dead time, and limited dv/dt for the semiconductors. The derived equations are verified with a 20kW prototype. Measurements done with the prototype show a significant improvement over the idealized, lossless equations. This allows for predictive, open loop (sensor less) control of the DAB. The measurements show an accurate and fast step response of the DAB converter.