High step‐up active switched coupled inductor DC‐DC converter with voltage multiplier

Abstract

High step-up DC-DC converters are commonly used in new energy applications such as DC microgrid, photovoltaic cell, and fuel cell. Thus, this article introduces a new nonisolated high step-up DC-DC converter based on active switched coupled inductor with a voltage multiplier cell. The proposed converter presents low current and voltage stress across the switches owing of the dual active switches structure. Besides that, by the voltage multiplier cell (one diode and one capacitor), the voltage gain of proposed converter is increased. In addition, it can be highlighted that the proposed converter has low component count, simplicity of operation in continuous and discontinuous conduction mode, and energy stored in the leakage inductor that is recycled in the capacitor of voltage multiplier cell. This article discussed the principle of operation, the ideal and nonideal voltage gain, external characteristic, voltage and current stress, design guidelines, and performance comparison with previous high step-up converters. Finally, a prototype circuit with input power 300 W, input voltage 30 V, and output voltage 400 V was built in the laboratory to verify the theoretical evaluation, and the maximum achieved efficiency was 95.35% at nominal power 300 W. K E Y W O R D Sactive switched coupled inductor, active switched inductor, high step-up, high voltage gain, voltage multiplier | INTRODUCTIONDistributed generation is an alternative to the existing global energy system, becoming a promising candidate for the more efficient use of energy, economic-financial and environmental resources. Several sources can be considered in the scope of distributed generation, such as fuel cells (FC) and the photovoltaic cells (PV). [1][2][3] These sources provide a low DC voltage (typically <50 V), so a high step-up DC-DC converter is required to increase this low voltage to high output voltage. 4 The standard boost converter and flyback converter are, respectively, the simplest nonisolated and isolated step-up converters. However, in these applications where high voltage gain is required, these standard converters cannot achieve good performance, due to the extreme duty cycle or high turns ratio of coupled inductor (CI) required to reach such a goal. In this situation, the parasitic resistances of components or leakage inductance of CI result in large conduction losses, high copper losses of windings, and overvoltage problem on semiconductors. 5,6

Evaluation of cascaded combinations of boost DC–DC converter and three‐winding coupled inductor for high‐voltage gain applications

“…In this section, the magnetizing inductor will be designed with an overall relationship that is defined in (7). To find the desired value, consider Table 4.…”

“…By substituting the values from Table 4 in (7), the value of L m ¼ 100μH is obtained. In this way, the value of L m ¼ 150μH was adopted.…”

“…[3][4][5] Conventional DC-DC converters cannot achieve this desired high gain, since they need high duty cycle values. 6,7 In this condition, the conduction losses increase due to the intrinsic resistances of the components, lower voltage, and current stresses on the components. 8,9 In this way, many solutions to improve these features and some techniques of high-voltage gain can be used.…”

“…Having as input parameters voltages ( ) lower than 50 V, 1,2 such as photovoltaic panels or fuel cells, and output voltages ( ) that reach 400 V, these converts must achieve a voltage gain lower than 3–5 . Conventional DC–DC converters cannot achieve this desired high gain, since they need high duty cycle values 6,7 . In this condition, the conduction losses increase due to the intrinsic resistances of the components, lower voltage, and current stresses on the components 8,9 .…”