A quintuple phase shift modulation scheme in multilevel dual active bridge converter for battery energy storage system

Generally, the dual active bridge (DAB) bidirectional DC-DC converter suffers from harmonics in the high-frequency link (HFL) conversion stage while operating under any modulation scheme. This paper proposes a quintuple phase shift (QPS) modulation scheme to suppress the harmonics under the whole operating range. A bidirectional auxiliary switch in the low voltage bridge produces a five-level output, which alleviates harmonic components of HFL current. The total harmonic distortion (THD) analysis is done for various operating conditions and is compared with the conventional modulation scheme, such as single phase shift and dual phase shift. The THD can be reduced in the entire power transmission for the proposed modulation scheme by defining the suitable phase shift ratios. Also, the power flow analysis under QPS modulation is reported in this paper. To validate the proposed approach's theoretical performance, simulation results are obtained under different operating conditions and verified with experimental results. The QPS modulation is implemented using the Spartan 3AN FPGA processor.