A Method for Stabilizing Dual Active Bridge Converters With Constant Power Loads

Dual Active Bridge (DAB)-based energy storage systems are the key to integrating renewable energy sources into the power grid. However, DAB converters can become unstable due to the negative impedance characteristic of constant power loads (CPLs), posing a risk to the overall system stability. To address this issue, a stabilization method based on inductor saturation is proposed. This method ensures converter stability by expanding its stability region, mitigating the risk of destabilization from fast-acting transients. Based on the mathematical analysis that uses full-order continuous-time average models and the characteristics of a CPL, the proposed method effectively stabilizes the DAB converter by expanding the stability region and achieves a fast dynamic response, even under large signal variations. Unlike other advanced stabilization methods, this approach does not require any modification of the main control objectives, such as bandwidth, voltage regulation, or load performance. The experimental results support the theoretical analysis, demonstrating the effectiveness of the proposed converter and showing an improvement in the overall efficiency of the converter under high-load conditions.