Summary In this paper, a modified and improved high gain dc–dc boost converter is proposed. The converter has utilized two voltage multiplier cells (VMCs) comprising switched capacitors (SC) and switched inductors (SL) to increase the voltage gain of the converter. The basic concept of these switched topologies is that when the switch is ON, the energy is stored by the inductor and the capacitor transfers its energy to load and inductor. In the OFF cycle, the inductor transfers its energy to the capacitor, and, simultaneously, capacitor is charged through input voltage also. As compared to other nonisolated topologies, the proposed converter has a high voltage gain and low voltage stress across semiconductor devices. The voltage stress on all capacitors except the output capacitor is less than the voltage across the load. A detailed analysis of the converter in continuous conduction (CCM) and discontinuous conduction modes (DCM) is shown. The proposed converter has a peak efficiency of 94.8%. For the efficiency calculation of the proposed topology, PLECS software is used. The experimental results agree with the theoretical analysis and validate the working and performance of the proposed converter.

To overcome the problems associated with Z-source-based DC-DC converters, a quasi-Z-source (QZS)-based high-gain DC-DC boost converter with switched capacitors is proposed in this work. Z-source-based DC-DC converters have problems like low-voltage gain, discontinuous input current, and high-voltage stress on the active and passive components. The proposed converter can produce a high-voltage gain of more than 10 times for a duty cycle of less than 0.5. The converter has other desirable features like reduced voltage stress across the switching components and continuous input current (CIC). It comprises a QZS cell made up of switched inductors and a voltage multiplier cell (VMC) made up of switched capacitors. The power loss analysis is done using PLECS software by incorporating the real parameters of switches and diodes from the datasheet. A hardware prototype of 200 W is developed in the laboratory to verify the working of the converter. In experimental results for an output power of 200 W, the converter is operated with a source voltage of 33 V at a duty ratio of 0.4 providing an output voltage of 395 V. The converter performance is good in open-loop conditions and is verified through experimental results. K E Y W O R D S duty ratio (λ), quasi-Z-source (QZS), voltage multiplier cell (VMC), voltage stress | INTRODUCTIONNowadays, gain DC-DC converters have found applications in electric vehicles (EVs), DC microgrids, switch-mode power supplies, and robotics to name a few. The power range of these high-gain converters varies from few milliwatts to a kilowatt range. The main objective is to build a topology with a high gain and reduced number of components. Desirable features like low voltage and current stress, common ground with low ripple in input current make the highgain converter an attractive choice for renewable energy applications. Conventional step-up converters and their variants need to be operated at a high duty ratio (λ) to obtain high-voltage gain. Consequently, the efficiency decreases, and the stress across the components increases. Moreover, the low and fluctuating output voltage of the PV panel cannot be fed to the inverter directly; it must be boosted with reduced ripple using a high-gain converter. 1,2 In Figure 1, it is depicted that a high-gain DC-DC converter can effectively boost the voltage from various sources like fuel cells, solar PV modules, battery, and an ultra-capacitor. These converters are used at the front end of a grid-connected inverter to maintain the DC-link voltage. The DC-DC converters have isolated and non-isolated structures. The isolated structures

High gain dc-dc converters are used in several applications which include solar photovoltaic system, switch-mode power supplies and fuel cells. In this paper, an ultra-high gain dc-dc boost converter is proposed and analysed in detail. The converter has a gain of six times as compared with the boost converter. The high gain is achieved by utilizing switched inductors and switched capacitors. A modified voltage multiplier cell (VMC) with switched inductors is proposed. The converter has a single switch which makes its operation easy. Moreover, the voltage across the switch, diodes and capacitors are less than the output voltage which increases the overall efficiency of the converter. The converter performance in steady-state is analysed in detail and it is compared with other latest high gain converters. The working of the converter in non-ideal conditions is also discussed in detail. The loss analysis is done using PLECS software by incorporating the real models of switches and diodes from the datasheet. To confirm and validate the working of the proposed converter a hardware prototype of 200 W is developed in the laboratory. The converter achieves high gain at low duty ratios and its performance is found to be good in open and closed loop conditions. INDEX TERMSBoost Converter, DC Microgrid, Duty cycle, Ultra High Gain, Voltage stress Battery Fuel Cell High Gain DC-DC Converter Solar PV Cell Low DC Voltage (12-60V) High DC Voltage (200 -300V

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Voltage lift is a well‐known technique to improve the voltage gain of the converter. A combination of switched inductor and the conventional voltage lift technique can be used to achieve high gain, but the semiconductor's stress is still high. An improved voltage lift technique by employing an extra diode and capacitor and a switched inductor is proposed, which significantly increases the voltage boosting factor and reduces the voltage stress of semiconductor devices. The proposed converter is transformerless and non‐isolated in nature. The proposed topology has a continuous input source current and has a common connection between the source and the load. The converter is controlled by a single switch, making it simple to use. The steady‐state relations are drawn out in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The effect of the unequal inductance on the voltage gain is carried out in detail. The improved voltage lift technique can develop the n‐stage converter to improve voltage gain further and reduce stress on semiconductors. The proposed topology is compared with the recent converters, and the effect of the non‐idealities on the voltage gain and losses occurring in the components is discussed in detail. A hardware prototype with a rating of 20V/300V, 250 W is built to test the suggested topology's performance and theoretical analysis. At a 20‐V input, the highest efficiency was measured to be 95.8%.