This study presents a control system to track the sinusoidal ripple current (SRC) of lithium (Li)-ion batteries. In this method, a combination of a DC and a sinusoidal ripple current is injected to the battery. By choosing the appropriate frequency, the minimum AC impedance of the battery is obtained. This study, the impact of temperature has been considered as a protection criterion in the proposed charge algorithm, also a state-space model of the charger system has been developed, and finally a pole placement controller has been proposed to control charging current. To evaluate the design, a laboratory setup has been implemented to obtain experimental results from a 1 kW Li-ion battery pack. Also, simulations have been carried out by Simulink/MATLAB. The proposed pole placement control method for tracking of SRC and the optimal frequency detection algorithm have been designed and tested on a practical 10 Ah Li iron phosphate battery pack in different charge modes. In addition, results of the conventional proportional-integrator (PI) controller have been compared with the proposed controller. Both simulation and experimental results show the effectiveness of the proposed algorithm and control system to track SRC reference current in all frequencies.

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This study focuses on considering battery one time constant model in the design of controllers of a two-stage AC/DC and DC/DC battery charger using the small-signal approach. For this aim, small-signal models of DC/DC and AC/DC converters and also the battery model are obtained. Moreover, the effect of disturbance terms are analysed to be omitted in controller loops. Simulation and experimental results of a 1 kW laboratory prototype show appropriate performance of designed controllers in tracking reference signals. Also, tuned controllers using this approach have guaranteed unity power factor and low total harmonic distortion. Furthermore, a complete charge cycle of a lithium-ion battery evaluates the performance of the converter in different constant current/voltage controlling modes. In comparison with restive model consideration, results show a more accurate model with grater damping ration and better stability characteristics.

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