||This dissertation proposes a dynamic impedance method and a projection method to respectively estimate the state-of-charge (SOC) and the state-of-health (SOH) of batteries. For the proposed methods, we defined the ratio between the changes in voltage and the changes in current during the charging and discharging processes of battery modules as the dynamic impedance, which further served as the basis to calculate the SOC of the battery. The proposed techniques do not require initial values, and the proposed dynamic impedance can better reflect the true electrical characteristics of batteries than conventional estimation methods. Furthermore, real-time calculations can be achieved using the proposed techniques. The SOH of batteries degenerates as the batteries age, which also changes the characteristics of the dynamic impedance. The projection method thus determines the SOH based on the rate of change in dynamic impedance with respect to the SOC. In this dissertation, the principle of the proposed techniques is detailed. And the mathematic model is also discussed in detail. Finally, all the experimental results agree with the theoretical predictions.
In order to use the proposed technique for some applications, we developed two SOC and SOH real-time estimation systems with different structures. The microcontroller is used to be the control core of the systems. Besides, they also combined with the battery management system (BMS) and the detection circuit to capture the data from the batteries, respectively. Furthermore, the proposed estimation technique was adopted into the developed systems to implement the real-time estimation feature. Moreover, an on-board LiFePO4 charger based on digital control incorporating with the proposed estimation technique is also implemented in this dissertation. Therefore, the microcontroller will calculate the corresponding charging current depends on the initial SOC and the selected charging mode when battery is charging. Finally, the hardware structures of the implemented systems are detailed in this dissertation. And the complete design considerations and algorithm are also described in detail. And then, the results of experiments verify the accuracy and feasibility of the proposed systems.