Integration Method of Clamp Circuit and Auxiliary Power Supply for Hybrid DAB Converters in Series-Connected Battery Swapping Stations

Compared to electric vehicle battery swapping stations (BSSs) based on dc voltage bus (DVB), the series-connected BSS based on dc current bus (DCB) can achieve independent control of each battery at a lower cost, presenting foreseeable application prospects. However, this system necessitates a hybrid dual active bridge (HDAB) converter capable of connecting both current and voltage sources (VSs). The current-source-side (CS-side) devices are prone to voltage spikes and need clamp circuits. Moreover, a dedicated isolation conversion stage (ICS) is required to provide energy to the CS-side auxiliary power supply (APS). This article proposes a solution combining clamp circuits with APS. By improving the topology and control, the proposed solution not only reduces the voltage and current stress of the clamp circuit itself but also ensures good clamping effects. Moreover, the CS-side APS has two fault-tolerant power inputs, enhancing reliability. As a result, the dedicated ICS has been eliminated, reducing the cost and size of additional circuits. The experimental results validate the effectiveness and advantages of the method proposed in this article.