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High-gain DC/DC converters with high efficiency are needed in dc microgrid owed to the low voltage of power sources, e.g., photovoltaic-cell and fuel-cell. This paper proposed a new high-gain double-duty-triple-mode (DDTM) converter for dc-microgrid applications. The proposed DDTM converter operates in three modes to achieve higher voltage gain without utilizing transformer, coupled inductor, voltage multiplier, and multiple voltage lifting techniques, e.g., triple, quadruple voltage lift. The modes of operation of the converter are controlled through three switches with two distinct duty ratios (double duty) to achieve wide range duty ratio. The operating principle, voltage gain analysis, and efficiency analysis of the proposed converter are discussed in detail and to show its benefits comparison is provided with the existing high-gain converters. The boundary operating condition for continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is presented. The prototype of the proposed converters with 500-W power is implemented in the laboratory and experimentally investigated, which validate the performance and feasibility of the proposed converter. Due to double duty control, the proposed converter can be controlled in different ways and the thorough discussion on controlling of the converter is provided as a future scope. (min) L1 and I (min) L2 Lower peak of current through inductor L 1 and L 2 I L1 and I L2 Peak to peak current ripples of inductor L 1 , L 2 v C1 and v C2 Voltage across capacitor C 1 , C 2 V C1 and V C2 Average voltage across capacitor C 1 , C 2 v D1 and v D2 Voltage across diodes D 1 , D 2 V D1 and V D2 Average voltage across diodes D 1 , D 2 i S1 , i S2 , and i S3 Current through switches S 1 , S 2 , S 3 v S1 and v S2 Voltage across switches S 1 , S 2 v AB Voltage across AB junction (diode D + switch S 3) v 1 and v 2 Input and output voltage (average value of V 1 and V 2) R 1 Series resistance of input voltage i 1 and i 2 Input and output current I 1 and I 2 Average value of Input and output current v GS1 , v GS2 , and v GS3 Voltage magnitude of gate pulse for switches S 1 , S 2 , S 3 I, II and III (in superscript) Defines the values in Mode I, II and III χ B Boundary normalized inductor time constant χ Normalized inductor time constant

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DC microgrid is gaining attraction and a recent trend in distribution power generation system due to penetration of renewables (especially Photovoltaic (PV) or Fuel Cell (FC)). In this paper, a new Triple-Switch-Triple-Mode High Step-Up converter (TSTM-HS converter) is presented for DC microgrid applications. In the proposed converter, voltage lift technique is employed and range of duty cycle is extended by incorporating an additional switch in converter circuitry. By doing this, high voltage conversion ratio is achieved without using a transformer, coupled inductor, and multiple stages of switched capacitors. Moreover, the TSTM-HS converter operated in three modes with two types of the duty cycles to achieve low to high voltage conversion without using high duty cycle for each switch. The effects of difference in the inductance values on the regulation and operating behavior of the TSTM-HS converter are discussed. The Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) characteristics of TSTM-HS converter are discussed in detail with steady-state analysis and boundary condition. The comparison is provided to highlight the benefits of the TSTM-HS converter. The selection of semiconductor devices and the design of reactive components are discussed for the TSTM-HS converter. The experimental results of the proposed converter are provided which validate the theoretical approach, performance, and feasibility of converter.

High efficiency is an important requirement from DC-DC converter in DC microgrid system when integrated with renewable energy sources. This study proposes a new tri-switching state non-isolated high gain boost converter for 400 V DC microgrid applications. The proposed converter developed by modifying the conventional boost converter with advantageous features such as; high-voltage gain operation with two different duty pulses to overcome the restriction of high duty ratio and continuous input current. Moreover, semiconductor components in the proposed converter are subjected to reduced voltage stress for a shorter duration when compared to conventional existing topologies. Steady state (with and without non-idealities consideration) and performance analysis are presented to validate the viability of the proposed converter for high gain operation in grid-connected systems. For experimental validation, a prototype model of the proposed converter is developed for 31 V/400 V, 500 W and operated at 50 kHz switching frequency. The converter is tested for a power range of 100-500 W for two different duty range (case: 1-k 1 kept fixed and k 2 is varied, case: 2-k 2 kept fixed and k 1 is varied) to validate the consistency in output voltage. Hardware results obtained validates superior performance and higher efficiency compared to conventional existing topologies.