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ABSTRACT In this article, a bidirectional DC‐AC modulation strategy for series resonant dual active bridge converter (SR‐DAB) is proposed. This modulation strategy combines phase shift (PS) and variable frequency (VF), which utilize four control variables, namely, three PS ratios and switching frequency. Three of four control variables are used for every operating scenario. Modulation methods under both buck and boost modes are considered and designed to attain a wide voltage gain range. Situations when modulation variables reach near transition limits are also given attention by introducing the notion of transition mode to realize smooth transition. The modulation strategy is optimized and designed by considering the operating constraints and the power losses in all aspects. Comparison of this optimization strategy with other strategies is carried out to prove the advantages of the proposed strategy. Finally, a 500‐W prototype is designed and built, which can operate under the condition of input DC voltage 10–50 V and output AC voltage 220 Vrms, 50 Hz, and the measured peak efficiency reaches 96.2%. [ABSTRACT FROM AUTHOR]

A new multiport DC–AC converter is proposed for standalone and off‐grid tied applications. The configuration converts power from DC to AC form in a single stage with suitable voltage gain. To increase the certainty of supporting power, the converter is designed to operate in four modes, including battery‐alone mode. The other advantage of the presented work is supplying the output power during unbalanced voltage conditions of the input ports. The advanced features of the converter for being used in standalone applications are related to the suitable placement and structure of the bidirectional port. In addition, the configuration is designed in a way to contain appropriate structural properties such as the existence of a common ground between the DC section and inverter, continuity of input currents, configured by an acceptable number of components, and low‐voltage stress on the DC–DC section's switches. Furthermore, it has an impedance network to protect the inverter's switches in a shoot‐through state. To confirm the converter advantages from the mentioned points of view, it has been compared with similar configurations. A prototype rated at 110 V is prepared to demonstrate the advantages of the converter performance per different conditions. The results of the steady‐state and transient experiments validate the suitability of the presented converter. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new single‐phase multi‐port DC–AC converter with high voltage gain in low duty cycle. The operation of the proposed converter consists of four modes, especially battery‐alone mode, which makes it appropriate for stand‐alone renewable applications. Using a suitable boosting method, this converter can achieve high voltage gain in all modes. The high gain performance of the converter occurs at both low shoot‐through duty cycle and high modulation index. Therefore, the output voltage and current harmonics as well as the filter size are reduced. In addition, the converter transfers the power with a continuous current through its input ports and has a common ground between the input sources and the inverter bridge. The positive features of this converter are the result of the appropriate design and localization of the bidirectional port that connects the battery to the converter. The proposed configuration includes an impedance network that protects the converter in the shoot‐through states and takes the advantage of the shoot through in its boosting performance. Another advantage of the proposed converter is that the voltage stress on the power switches on the DC side is considerably low. In order to validate the feasibility and effectiveness of the converter, a prototype rated at 110 V is prepared and tested. [ABSTRACT FROM AUTHOR]