Adaptive Dead Time Compensation for Continuous Cross-Period Single Phase-Shift Control of Dual Active Bridge Converters

Abstract

The load transient response of a power converter is an important property, especially in a test equipment application. The dynamic behavior of a dual active bridge converter mainly depends on the switching frequency, the transformer leakage inductance, and the capacitor bank size. Using the Continuous Cross-Period Single Phase-Shift control, an excellent load transient response can be achieved without the need for expensive hardware components. However, in practical applications, the switch delay and the required inserted dead time distort the current waveform, increasing the electromagnetic noise and reducing the effectiveness of the regulation. In this paper, an adaptive dead time compensation technique is presented, which eliminates such phenomenon. The effects of dead time are analyzed, and mathematical formulas are derived, from which the adaptive compensation technique is formalized. The algorithm is implemented on a TMS320F28075 DSP and tested in a HIL environment. The study revealed that the proposed adaptive technique could mitigate the current waveform distortions.