A low cost battery equalizing scheme with buck-boost and series LC converter using synchronous phase-shift controller

Abstract

This paper presents a modularized buck-boost and series LC converter (BBSLCC) circuit for series battery equalizers. The proposed topology has numerous advantages. First, the number of switches in the equalizer is equal to the number of the battery cells needs to be balanced in the string. This is so called one-switch-per-cell, which is a great advantage over the traditional buck-boost converter, since it requires almost twoswitch-per-cell to balance. Second, unlike many other existing one-switchper-cell equalizers, the proposed circuit has the advantage in the modularization design and low voltage stress requirement on the switches. Third, the peak current of the balancing capacitor are suppressed by the synchronous phase-shift controller (SPSC) which can be easily implemented by sensing the zero crossing of the LC resonant current. By using the proposed controller, the speed of the battery equalizing process is also accelerated. In this paper, the proposed topology is first presented, and the operating principle is illustrated. Afterwards, the phase-shift time and the transferred energy of the BBSLCC circuit are calculated to demonstrate the proposed control strategy details. The relationships between the phase-shift time and other circuit parameters such as the inductance and the capacitance are also analyzed. The simulation results and the experimental results are finally demonstrated and verified the theoretical analysis on the performance of the proposed BBSLCC circuit.

A Battery Cell Equalisation System Based on a Supercapacitors Tank and DC–DC Converters for Automotive Applications

“…For the SCES charge, the two-switch forward converter (Figure 9) is a good choice, as can be concluded from its experimental verification. The results comply with and complete the results published in [49][50][51][52][53][54][55].…”

“…As shown in the comprehensive active equalisation techniques in [49], the multiple bi-directional converters architecture, based on individual converters per each battery cell, gives independent operation with microprocessor control. The transformer-less bi-directional buck-boost converters, accommodated for battery cell equalisation, have the potential to offer a compact and budget-friendly solution, as shown in [50]. Further modifications in the converter-battery circuit connection could achieve any-cells-to-anycells and integrate buck-boost converters and parallel-connected switched-capacitors [51], improving the system's flexibility, balancing speed, and efficiency.…”

Interleaved PFC balance charger with passive lossless snubber for series-connected batteries

“…Multi-output chargers are used to directly charge the series-connected batteries and eliminate the voltage imbalances during charging. Charge equalization circuits are proposed to transfer the charges among the seriesconnected batteries to eliminate the voltage imbalance [7][8][9][10][11]. However, the energy transferring between each battery would cause additional power losses.…”

Battery Equalization by Fly-Back Transformers with Inductance, Capacitance and Diode Absorbing Circuits

“…The block circuit composed of resistance, capacitance and diode (RCD) is used in the converter to effectively suppress the voltage spike problem, however, the energy absorbed by the power tube is dissipated as heat by the electric resistance, which leads to a reduction of the topology efficiency [27]. Compared with the RCD clamp circuit, lossless absorption networka composed of inductance, capacitance and diode (LCD) can not only return the energy to the power supply without resistance heat loss, but also realize the soft switching power transistor in the absorption peak voltage at the same time, therefore, improving the efficiency and reliability of the converter [28].…”