Implementation of Adaptive Hysteresis-Band Current Control for Bidirectional H-Bridge DC-DC Converter

The substantial adoption of electric vehicles (EVs) has the potential to disrupt the power grid due to uncontrolled charging. A promising solution is Vehicle-to-Grid (V2G) technology, which allows EVs to return surplus energy to the grid to maintain reliability. However, a key challenge is developing a bidirectional converter with a rapid response that can also maintain a constant switching frequency to avoid harmonic disturbances. This study introduces an innovative adaptive hysteresis bandwidth current control method for H-bridge converters. This method provides a rapid and precise response to dynamic current and voltage fluctuations while maintaining a constant switching frequency for the MOSFET. The adaptive bandwidth values are mathematically derived from converter principles and implemented via a lookup table in a microcontroller. The simulation results showed a response time of less than 1 millisecond without overshoot. Experimental validation demonstrated the system’s efficacy in maintaining a constant switching frequency under dynamic changes. In charging mode, the average frequency was 14.88 kHz (with a range of 0.79 kHz), and the efficiency was 85.74%, while the fixed hysteresis band has a frequency variation of 14.26 kHz to 20.66 kHz (with a range of 6.37 kHz). In discharge mode, the average frequency was 16.62 kHz (with a range of 0.33 kHz), the efficiency was 77.40%, and the fixed bandwidth is approximately 2.3 kHz on frequency from 15.82 kHz to 18.12 kHz. With adaptive control, the frequency change range is successfully constant with a small range.