A Novel Inductor-Based Non-Dissipative Equalizer

Abstract

Large numbers of non-dissipative equalizers have been proposed for solving the inconsistency problem of lithium battery strings. However, these equalizers face problems such as slow speed or using excessively large numbers of energy storage elements. This paper improved a multiple switch-inductors equalizer (MSIE), and proposed a novel inductor-based non-dissipative equalizer (NIBNDE). A simulation is built to compare the NIBNDE with two other equalizers, which indicated that the NIBNDE can reduce the number of energy storage elements while remaining at a good equalization speed. Experimental results validate the analysis of the simulation and the feasibility of the NIBNDE.

A Novel Lithium Battery Equalization Circuit with Any Number of Inductors

“…In order to equalize the cells, a large number of battery equalization circuits have been proposed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. These circuits can be divided into two types: dissipative circuits and non-dissipative circuits [4]. Among them, non-dissipative equalization circuits can be divided into three types according to the number of energy storage components: the first type is shown in Figure 1; they only have one energy storage component, so they can only have two cells working at the same time, and the equalization current is small, which leads to the slow equalization speed [5,6].…”

“…The advantages of this circuit are small volume, simple control and low cost. As shown in Figure 2, the number of the energy storage components are about half of the number of the batteries in the second type [4,[7][8][9][10]. This type of circuit has several cells working at the same time and the equalization current is higher than the first type, so its equalization speed is faster than the first type.…”

“…For example, a 48 V electric bicycle battery pack contains 12 batteries that need to be balanced. The first type of equalization circuit has only one inductor; one of the second type proposed in [4] has 6 inductors; and one of the third type proposed in [11] has 13 inductors. That is to say, the volume of the above three equalization circuits is fixed.…”