Bidirectional converter based on boost/buck DC‐DC converter for microgrids energy storage systems interface

Abstract

SummaryIn this paper, a new bidirectional nonisolated DC‐DC (direct current–direct current) converter to interface microgrid energy storage systems is proposed. This converter is based on the classical bidirectional boost/buck converter, the most used converter in microgrids and can operate both in step‐down and step‐up modes. Besides that, this converter presents low number of components, low voltage and current stress on components, simplicity of operation, low current ripple from low‐side power supply, and two different modes of operation: synchronous and asynchronous. In addition, in this paper, the modeling, control, and power losses estimate of the proposed converter are carried out and the performance of the converter in different aspects of the microgrid application is evaluated, such as step load, abrupt power flux change, and transient analysis. A prototype of 1 kW, 144 to 400 V, is developed in the laboratory to validate the theoretical evaluations of the proposed converter. Besides that, the proposed converter is also evaluated under different dynamic condition which illustrates the effectiveness of the converter. Finally, the maximum efficiency obtained is 97.1% for 500 W working in step‐down operation.

Análise e Desenvolvimento de um Conversor Bidirecional Não Isolado Baseado no Conversor Boost/ Buck CC-CC

“…Em (27), considerando o momento de descarga do capacitor, visto na Fig. 2(a), o tempo T se torna DT S e a corrente I cap se torna a corrente da carga R H , resultando em (28).…”

“…Reagrupando os termos de (28) e sabendo que C Heq é um capacitor equivalente formado por C H1 e C H2 , o valor destes capacitores em função da ondulação de corrente é apresentado em (29) .…”

“…Os ganhos estáticos, tanto em modo elevador quanto abaixador, são os mesmos para todos conversores. Em termos de quantidade de interruptores, o conversor clássico apresenta o menor número, seguido pelo conversor proposto, conversor [28] e por fim, com maior número de interruptores o conversor [29]. Em relação ao esforço de tensão sobre os interruptores de entrada, o conversor [28]…”

“…Em potência nominal para modo rebaixador, o conversor [28] alcançou a maior eficiência (96 %), seguido pelo conversor [29] (87,65 %), conversor proposto (85,8 %), e por fim o conversor clássico (84,01 %).…”

A single switch hybrid quadratic converter for grid‐integrated renewable energy system

“…Due to leakage inductance, the circulation losses pull out the efficiency of the converter. 11 Moreover, it yields the large voltage spikes during switching action, especially at OFF-state condition, which resulting to substantial losses of the converter. 12 This condition is true in the converter operating with a coupled inductor.…”