Smooth DC-Link Y-Source Inverters: Suppression of Shoot-Through Current and Avoiding DC Magnetism

Abstract

The Y-source impedance network is truly referred to as the origin of the magnetically coupled impedance source (MCIS) inverters. The key characteristics, including high boost capability and design flexibility, are associated with the coupled inductor turn ratio. However, the magnetic element brings some practical challenges, such as voltage spikes, high shoot-through (ST) current, and bulky coupled inductors. This paper proposes two new Y-source inverters with clamped DC-link voltage. Due to the high boost ability, they are suitable for single-stage high gain inversions. Additionally, the significant reduction in the amplitude of the ST current leads to a reduction of the total power loss and capacity of the reactive component. Another attractive characteristic is that the Y-shaped coupled inductor's stored energy is no longer affected by the power rating of the converter, as a result of the zero dc magnetizing current. All these contribute to the high efficiency and power density of the proposed converters. The design guidelines of the components are presented and a thorough comparison with the state of the art is carried out. The achievements are then confirmed through extensive tests on a 500W laboratory setup.

A Comprehensive Small-Signal Model Formulation and Analysis for the Quasi-Y Impedance-Source Inverter

“…Despite the fact that I C2 = I N1 + i m , considering a large enough magnetizing inductance L m , i m is comparatively lower than I N1 in steady state and hence during shoot-through I C2 ≈ I N1 . Therefore, by substituting (18) for (20), it is possible to derive expressions for I N3 and I N2 with respect to I N1 and I C2 , as can be seen in ( 20) and (21).…”

“…The impedance-source configurations based on the Y-source network are of particular interest as they can provide one of the highest voltage gains, lower component quantity, and smaller shoot-through periods [17]. Moreover, the research conducted with Y-source impedance networks recently that was carried out covers different aspects of this class of impedance-source converter, ranging from (a) the proposition of new topologies, to reduce input current ripple [18] and allow soft-switching [19], higher voltage boosting gains through switched inductors [20], or the intrinsic damping of DC-link voltage spikes due to leakage inductances [21,22] ; (b) the review of Y-source based magnetic-coupled impedance source networks [23,24]; (c) applications with renewable energy sources based on solar or wind-based generators [25,26] and (d) the proposition of model-predictive control approaches [27]. However, none of these recent publications performs a comprehensive analysis of its proposed Y-source-based converters, with small-signal modeling based on state-space averaging, considering a dynamic evaluation of the DC-link control under impedance-network components parametric variations.…”

Improved High Step-Up Cockcroft-Walton Magnetic Coupling Inverter

“…However, similar to the existing magnetically coupled Z-source topologies, these inverters have a weak voltage boost ability at the low ST duty ratio ranges, which leads to impediments in the control of the converters. To overcome this drawback, switched coupled inductor impedance source converters have been presented in [19][20][21][22][23][24][25]. In addition, generalized Z-source and quasi-Z-source inverters based on Cockcroft-Walton multiplier voltage cells are proposed in [24].…”

Symmetric Wide-Input-Voltage Range Boost Z-Source DC–DC Converter With Reduced Current of Source and Active Components

“…In this regard, various structures of impedance source converters have been proposed by authors. The structures can be classified in three distinct categories, as proposed in [1]: using magnetically coupled inductors/transformers [2][3][4][5], improving and expanding the impedance network [6][7][8][9][10][11][12][13][14][15][16][17][18], and using extra active switches in the impedance network [19]. All these structures aim to achieve some of the following benefits: higher voltage gain, less inrush current, less stress on devices, higher efficiency and higher power density.…”

“…All these structures aim to achieve some of the following benefits: higher voltage gain, less inrush current, less stress on devices, higher efficiency and higher power density. Using coupled inductors, which leads to some particular structures like A-source, 𝛤-source, 𝛥-source, Ysource converters, is a fine method for increasing the voltage gain [2][3][4]. Another appropriate method that provides high voltage gain is utilizing the isolated high step-up DC-DC converters [5].…”