Battery model has been divided into the following components
[36]:
1) gassing current model;
2) capacity model;
3) voltage model;
4) SOC model.
The details of these models could be found in [36]. The level
of discharge of battery determines the life of the battery. Therefore,
it is important to monitor the SOC and control charging/discharging cycle of the battery. The intelligent control in Fig. 1,
includes this important factor.
With maximum battery voltage never exceeding the dc bus
voltage, a bidirectional half-bridge dc/dc converter is used,
which operated in boost mode when discharging and buck mode
when charging the battery. The buck–boost converter control
topology is adopted from [37] and shown in Fig. 7.