Rotating Phase Shedding for Interleaved DCDC Converter-Based EVs Fast DC Chargers

Fast dc chargers are the key enablers for the massive rollout of electric vehicles due to the reduced charging time. On the other hand, the rapid growth in battery technology with different voltages and charging requirements has imposed additional hurdles on the charger design to meet the efficiency requirements. Multiphase interleaved converters with conventional phase-shedding control improve the efficiency for a wide range of operations. However, they tend to operate certain phases, resulting in uneven thermal stress among the converter phases. This article proposes a rotating phase-shedding control to distribute the switching activities among all phases, enhancing the system's reliability while retaining the efficiency improvement. The proposed technique selects the proper number of active phases based on the required charging profile and periodically swaps them with other phases to even out the stress. The thermal profile is extracted to assess the thermal damage of the power switches. The performance of the proposed approach is evaluated and compared with the conventional phase shedding. The simulation and experimentally validated results confirm that the proposed technique achieves a better even distribution of the thermal damage between the phases compared with the conventional one. This will ultimately extend the lifetime of the system.

Automated summary

Fast DC chargers play a crucial role in the widespread adoption of electric vehicles by reducing charging time. However, the increasing variety in battery technology poses challenges for charger design. This article proposes a rotating phase-shedding control technique to evenly distribute the thermal stress among all phases, improving system reliability and efficiency. Through simulations and experiments, the proposed approach is shown to achieve a better thermal damage distribution compared to conventional phase shedding, ultimately extending the system's lifetime.