Design and implementation of modified SEPIC high gain DC‐DC converter for DC microgrid applications

Abstract

Summary In DC microgrids, power converters are essential for interconnecting and controlling power flow from the renewable sources such as solar PV, wind, fuel cell, and so on with the DC grid link. A lot of DC‐DC power converters available in the literatures are used to boost the low voltage from the renewable sources to the high voltage and also to track the maximum power from these sources. To boost the output voltage, high gain converters are required. To increase the static gain of the converters, many techniques such as using voltage lift, switched capacitor, coupled inductor, and so on are used. This paper presents a novel high gain DC‐DC converter that does not use the above techniques for voltage boosting. An inductive reactive element is added in series with a switch to boost the voltage gain. This inductor is connected in parallel with the source voltage when the switches are in ON position and in series with the source when the switches are in OFF position. The proposed converter is designed to produce the output voltage of 380 V for the input of 48 V. The converter is designed to handle the power of 1 kW. With the use of the voltage boosting element, a maximum voltage gain of 28 is achieved and the efficiency of converter is about 91.9%. The performance of the proposed converter is simulated and analyzed for various conditions such as variation in input voltage, reference voltage, and load power and also for motor loads. The experimental prototype model is also built and the hardware results are shown in this paper to validate the simulation results.

A Transformerless Boost-Modified Cuk Combined Single-Switch DC-DC Converter Topology with Enhanced Voltage Gain

“…The proposed hybrid topology exhibits improved voltage gain than that of the topologies shown in Figure 1(a), Figure 1(b), and in [21]. Also, the low voltage stress occurs on the power switch and the diodes.…”

“…The single switch non-isolated converter topologies are modified by adding extra diodes and passive elements in order to improve the voltage gain [13][14][15][16][17][18][19]. The researchers have also developed non-isolated topologies with extra power switches, diodes and passive components for enhanced static voltage gain [20,21]. The use of more number of switching and passive devices in the non-isolated topologies proposed in [13][14][15][16][17][18][19][20][21] leads to the complexity of the power circuit and the control strategy.…”

“…The researchers have also developed non-isolated topologies with extra power switches, diodes and passive components for enhanced static voltage gain [20,21]. The use of more number of switching and passive devices in the non-isolated topologies proposed in [13][14][15][16][17][18][19][20][21] leads to the complexity of the power circuit and the control strategy. Hence, the researchers concentrated on developing the hybrid non-isolated single switch DC-DC converter topologies with simple control strategy, high voltage gain capability and high power conversion efficiency [22][23][24].…”

A three‐level isolated dc‐dc SEPIC converter with parallel‐connected output

“…Converters derived from the single‐ended primary‐inductance converter (SEPIC) structure are widely used in renewable energies applications 3–7 . Other examples where the SEPIC is also used include power factor correction (PFC), 8–11 LED lighting drivers, 12–16 battery chargers 17–19 and DC microgrids 20 …”

“…[3][4][5][6][7] Other examples where the SEPIC is also used include power factor correction (PFC), [8][9][10][11] LED lighting drivers, [12][13][14][15][16] battery chargers [17][18][19] and DC microgrids. 20 The SEPIC-type topologies present attractive characteristics when compared with other structures, including (i) continuous input current with low ripple; (ii) operation as a step-down/step-up voltage regulator without reversing the polarity of the output voltage, unlike the buck-boost, and Cùk converters; (iii) operating with a wide input voltage range due to step-up/step-down static gain; (iv) output voltage source characteristic, attractive for some applications;…”