مقاله انگلیسی رایگان در مورد یک مبدل جدید DC-DC سه سطحی – IEEE 2018

MULTIPORT dc-dc converters have attracted a great deal of research interest recently, which could be attributed to the growing demand of renewable energy, the development of power electronic systems, and the increasing use of microgrids. Compared to several separate dc-dc converters, multiport dc-dc converters suggest a compact structure with a lower cost and less component counts [1]–[5]. At higher voltages, switches voltage stress is a major challenge for multiport dc-dc converters. The reason for that are the issues such as the cost and the inaccessibility of high voltage switches, which could also have a negative effect on overall efficiency due to their high forward voltage drop and ON-state resistance. Moreover, the typical semiconductors used in high voltage applications are IGCT and high voltage IGBT [6], [7], which are not good solutions for multiport dc-dc converters. Due to the very high switching losses of those switches, their switching frequency is practically limited to about 1 KHz [6], [7]; therefore, the size of the passive components will increase dramatically. This study aimed at designing a high-efficiency multiport dc-dc converter with reduced voltage stress across semiconductor devices and shrunken passive components size. Reference [8] proposes a bidirectional multiple-input multiple-output dc-dc converter based on the triangular modular multilevel dc-dc converter. In this converter, the voltage stress on switches is shared amongst the levels. In addition to its complex control system, the converter is not capable of generating buck and boost output voltages at the same time. As a result, it requires two separate circuits with different topologies to generate each voltage separately. In [9], a non-isolated single-input dual-output dc-dc converter (SIDOC) is proposed, which one of its outputs is boost and the other one is buck at the same time. The converter’s topology is achieved through the substitution of two series-connected switches with the control switch of the conventional boost converter. The voltage stress on each switch and the diode is equal to the boost output voltage, making the converter appropriate for low-voltage applications. Meanwhile, because of high voltage stress on the diode and the series added switches, and also due to the lack of proper high input current distribution (which is typically the case in the single-input multiple-output converters) among the switches, the converter’s both conduction and switching losses are high, which can lead to a fairly low system efficiency. Reference [10] proposes an isolated SIDOC, which comprises four diodes and only one power switch. However, in order to increase the efficiency and cope with the high current stress, two paralleled high-current switches with soft-switching method have been used in the experimental prototype. A number of studies have been found proposing multiport multi-level converters [11]–[13]. In [12], a non-isolated SIDOC is proposed, which is a combination of the sepic and five-level boost converters.