Abstract：The dual active bridge（DAB）DC-AC converter faces challenges such as limited soft-switching range, high current stress, and low efficiency across a wide input voltage and load range. Although existing modulation strategies can enhance the performance of DAB converters, they typically require complex control and impose a high computational burden. As for topological improvements, most solutions are constrained by either a narrow input voltage range or structural complexity. Thus, a topology-construction concept for the DC-AC converter is proposed. The proposed approach dynamically adjusts the DAB stage's input voltage via a DC-DC converter, ensuring consistent operation under voltage-matching conditions. The two-stage four-switch Buck-Boost（FSBB）cascaded DAB-DC-AC converter is selected as an example. The front-stage FSBB converter employs a Buck-Boost modulation strategy. By introducing the intermediate bus-voltage reference $ v_{\mathrm{bus}}^{*} $ and the input voltage Vdc, the FSBB implements a composite control scheme that combines voltage feedforward and bus-voltage closed-loop control, ensuring fast and accurate bus-voltage tracking. Under the voltage-matching condition, the DAB-DC-AC converter does not require complex modulation and control strategies. Thus, the DAB stage employs single-phase-shift（SPS）modulation with a single PI controller to achieve stable, efficient power conversion. A 500 W experimental prototype has been built. Experimental results indicate that under the input voltage range of 32 V to 62 V, the proposed topology maintains a stable inductor Lk current stress of 8.4 A, which is significantly lower than the 16.2 A to 29.2 A in the single-stage DAB-DC-AC converter. In terms of soft-switching range, the single-stage DAB-DC-AC converter achieves zero-voltage switching（ZVS）for the switches only when the output voltage exceeds 126 V at an input voltage of 32 V. As the input voltage increases, the soft-switching range gradually decreases. In contrast, the proposed topology achieves ZVS at output voltages above 91 V under the same input conditions, with minimal sensitivity to input-voltage variations. In terms of efficiency, while the FSBB stage introduces additional switching and inductor losses, the DAB stage achieves lower losses due to its wider soft-switching range and lower inductor current. The proposed topology can maintain an efficiency range of 94.56%~95.65% across different input voltages. Over a wide load range, it can also achieve a stable, high-efficiency output compared with a single-stage DAB-DC-AC converter. The feasibility of the proposed topology construction is verified through theoretical analysis and tests. It simplifies the control structure of the DAB stage, reduces current stress, and enhances overall system performance across a wide range of input voltages and loads. Furthermore, it demonstrates a viable approach to designing isolated DC-AC converters across a wide range of operating conditions.
[1] 陈强, 杨师骁, 王世龙, 等. 单级DAB-DC/AC变换器的效率敏感因子研究[J]. 中国电机工程学报, 2025, 45(17): 6920-6930. Chen Qiang, Yang Shixiao, Wang Shilong, et al.Study on efficiency-sensitivity factor of single-stage DAB-DC/AC converter[J]. Proceedings of the CSEE, 2025, 45(17): 6920-6930. [2] Sha Deshang, Zhang Debin, Zhang Jiankun.A single-stage dual-active-bridge AC-DC converter employing mode transition based on real-time calculation[J]. IEEE Transactions on Power Electronics, 2021, 36(9): 10081-10088. [3] Saha J, Gorla N B Y, Subramaniam A, et al. Analysis of modulation and optimal design methodology for half-bridge matrix-based dual-active-bridge（MB-DAB）AC-DC converter[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(1): 881-894. [4] Jauch F, Biela J.Combined phase-shift and frequency modulation of a dual-active-bridge AC-DC converter with PFC[J]. IEEE Transactions on Power Electronics, 2016, 31(12): 8387-8397. [5] 刘述喜, 唐博, 陈鹤铭, 等. 直流微电网中双有源桥变换器的混合优化控制策略[J]. 电气工程学报, 2025, 20(1): 160-169. Liu Shuxi, Tang Bo, Chen Heming, et al.Hybrid optimal control strategy for dual active bridge converter in DC microgrids[J]. Journal of Electrical Engineering, 2025, 20(1): 160-169. [6] Chen Tianxiang, Yu Ruiyang, Ma Qingxuan, et al.Optimal control scheme for single-stage dual-active-bridge AC-DC converter[C]//2018 IEEE Energy Con-version Congress and Exposition（ECCE), Portland, OR, USA, 2018: 2860-2864. [7] Kwon O, Kim K S, Kwon B H.Highly efficient single-stage DAB microinverter using a novel modulation strategy to minimize reactive power[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(1): 544-552. [8] 王要强, 李灏, 李想, 等. 基于双模式变频移相调制的单级式双有源桥型DC-AC变换器[J]. 电工技术学报, 2024, 39(21): 6865-6876. Wang Yaoqiang, Li Hao, Li Xiang, et al.A single-stage dual active bridge dc-ac converter based on dual mode modulation of variable frequency and phase shift[J]. Transactions of China Electrotechnical Society, 2024, 39(21): 6865-6876. [9] Tian Qi, Huang A Q, Bai Hua, et al.A novel light load performance enhanced variable-switching-frequency and hybrid single-dual-phase-shift control for single-stage dual-active-bridge based AC/DC converter[C]//IECON 2016-42nd Annual Conference of the IEEE Industrial Electronics Society, Florence, Italy, 2016: 1227-1232. [10] Belkamel H, Kim H, Choi S.Interleaved totem-pole ZVS converter operating in CCM for single-stage bidirectional AC-DC conversion with high-frequency isolation[J]. IEEE Transactions on Power Electronics, 2021, 36(3): 3486-3495. [11] Nayak P, Rajashekara K, Pramanick S K.Soft-switched modulation technique for a single-stage matrix-type isolated DC-AC converter[J]. IEEE Transactions on Industry Applications, 2019, 55(6): 7642-7656. [12] Tawfik M A, Ehab M, Ahmed A, et al.Single-stage isolated DC-AC converter with continuous dynamic model and controller design[J]. IEEE Transactions on Industrial Electronics, 2023, 70(6): 5971-5981. [13] Cho Y W, Cha W J, Kwon J M, et al.High-efficiency bidirectional DAB inverter using a novel hybrid modulation for stand-alone power generating system with low input voltage[J]. IEEE Transactions on Power Electronics, 2016, 31(6): 4138-4147. [14] Xuan Yang, Yang Xu, Chen Wenjie, et al.A novel NPC dual-active-bridge converter with blocking capacitor for energy storage system[J]. IEEE Transac-tions on Power Electronics, 2019, 34(11): 10635-10649. [15] Lu Zhengmei, Su Mei, Xu Guo, et al.Switch-multiplexed quasi-two-stage isolated bidirectional Buck-DAB converter with full load ZVS range[J]. IEEE Transactions on Power Electronics, 2023, 38(9): 10541-10546. [16] Chen Qiang, Wang Shilong, Li Yuanbo, et al.High efficiency quasi-single-stage DAB-DC/AC converter with wide input voltage range[J]. IEEE Transactions on Power Electronics, 2025, 40(11): 16937-16952. [17] Heydari M, Huang Qingyun, Huang A Q.A 400W, 99.3% efficient GaN Buck-Boost converter[C]//2023 IEEE Applied Power Electronics Conference and Exposition（APEC), Orlando, FL, USA, 2023: 2223-2230. [18] Xu Changle, Liu Shuang, Guo Xiang, et al.A novel converter integrating Buck-Boost and DAB converter for wide input voltage[C]//IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society, Singapore, 2020: 2877-2882. [19] 杨志飞, 戈宝军, 董传友, 等. 面向超低温工况需求的铁磁材料铁心损耗计算模型与电导率计算方法[J]. 电工技术学报, 2025, 40(18): 5776-5785. Yang Zhifei, Ge Baojun, Dong Chuanyou, et al.Calculation model and conductivity calculation method for iron core loss of ferromagnetic materials for ultra-low temperature working conditions[J]. Transactions of China Electrotechnical Society, 2025, 40(18): 5776-5785. [20] 刘欢, 李永建, 张长庚, 等. 非正弦激励下纳米晶材料高频磁心损耗的计算方法改进与验证[J]. 电工技术学报, 2023, 38(5): 1217-1227. Liu Huan, Li Yongjian, Zhang Changgeng, et al.Calculation and experimental verification of core loss in high frequency transformer under non-sinusoidal excitation[J]. Transactions of China Electrotechnical Society, 2023, 38(5): 1217-1227. [21] 姜宇, 刘闯, 朱帝, 等. 新型无桥单级式双向高频链AC-DC变换器研究[J]. 中国电机工程学报, 2025, 45(14): 5621-5634. Jiang Yu, Liu Chuang, Zhu Di, et al.Research on a novel bridgeless single-stage bidirectional high-frequency link AC-DC converter[J]. Proceedings of the CSEE, 2025, 45(14): 5621-5634. [22] 王要强, 钟正阳, 李想, 等. 基于线性化的单级式双有源桥AC-DC变换器最小电流应力控制策略[J]. 电工技术学报, 2025, 40(10): 3224-3235. Wang Yaoqiang, Zhong Zhengyang, Li Xiang, et al.Linearization-based minimum current stress control strategy for single-stage dual active bridge AC-DC converter[J]. Transactions of China Electrotechnical Society, 2025, 40(10): 3224-3235. [23] Jeong S G, Kim K S, Kwon O, et al.Direct single-power-conversion bidirectional grid-connected inverter solving commutation problem[J]. IEEE Transactions on Industrial Electronics, 2020, 67(12): 10335-10345. [24] Belkhode S, Prabhu N, Benzaquen J, et al.Single-stage bidirectional inertia-less isolated dc/ac con-verter[C]//2024 IEEE Applied Power Electronics Conference and Exposition（APEC), Long Beach, CA, USA, 2024: 348-353.
2026, Vol. 41 
