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Summary In this paper, the concept of converter design, using the least number of elements and achieving high voltage gain at the low duty cycle, is proposed for the microgrids. One of the important issues in the microgrids is boosting the low voltage output of sources to the utility voltage level. Therefore, the step‐up DC‐DC converters are widely used in these systems to attain the utility voltage. The benchmarking of the converters mainly in terms of the voltage gain, efficiency, the number of active and passive components, stresses on semiconductors, and simplicity is considered. In this paper, a new extendable non‐isolated boost DC‐DC converter is presented. Comparing the conventional boost converter, the basic structure of the proposed converter has a high voltage gain and reduced stress on the switch. To increase the voltage gain, the basic structure of the proposed converter can be easily extended. The modulation technique employed is high‐frequency pulse‐width modulation (PWM). The detailed analysis of the proposed converter in continuous current mode (CCM) and discontinuous current mode (DCM) is presented. The relations between currents and voltages and the voltage gain in CCM and DCM are obtained. Experimental results are carried out to verify theoretical concepts by using the hardware prototype.

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Summary Isolated microgrids including several sources of clean energy such as photovoltaic system can be considered as the auxiliary source of power generation. However, unbalanced condition is inevitable in typical microgrids due to asymmetric power generation and consumption. To supply load from different distributed generation, an interface 4‐wire power converter is essential. A 4‐leg inverter with suitable control method is a beneficial solution to support unbalanced loading condition. However, high reliable low‐cost control method achieves more attention to avoid any power outage. As a result, a low‐cost sliding mode control method is proposed in this paper to control the output voltages of the 4‐leg inverter. The proposed method can provide fast dynamic response, fixed switching frequency, high robustness against model parameter mismatches, and external disturbances without any current sensors. Furthermore, to reduce the chattering of the sliding mode control method more effectively, an improved low‐cost method with adaptive discrete coefficient is also proposed. Finally, to evaluate the performance of the proposed method, a 3‐kW test bench with digital control board based on TMS320F28335 processor is provided.