Sliding-mode Control Research For Energy Bus Based Equalization Network Of Battery Pack In Series Connection

Traditional fossil energy provided the impetus to move forward for social development. However, these are non-renewable energy, besides the consumption of fossil energy caused great damage to our environment.Currently, many new energy has been widespread concern, such as solar, wind, etc., have been going gradually into the energy system, electric cars, electric bikes have been coming into our view. Energy storage devices are inseparable to generation and use of these energy. As its large capacity, long cycle life, low self-discharge and merit no memory effect, Lithium-ion batteries has been widely used, and became the most promising battery. While for each lithium battery’s performance in series couldn’t be completely same, so energy imbalances could occur during the process of charging and discharging, causing damage to the individual battery, and affect battery’s life. In order to ensure consistent characteristic attributes, and extend the life of battery pack, battery energy balance technology arises at the historic moment.This paper focuses on the circuit topology and control algorithm of battery energy balance system, we selected bi-directional equalization circuit as physical topology, to solve problems such as complex balanced structure, poor scalability, low control accuracy and low efficiency. Modular balancing system, improve the system’s ability to expand; as the feature of equalization circuit, non-minimum phase system, this paper proposed double feedback voltage control on the control algorithm, the algorithm improves the efficiency of a balanced equilibrium process, reducing time and balancing process balanced energy loss. The main work is as follows:① Study on the equalization circuit topology and analysis bidirectional Equalization circuit topology and the working modes in different parameters of the circuit, and the transfer way of topology when balancing. Build and analysis the Mathematical model of the circuit, and verify the principles of the circuit topology through ORCAD / Pspice. The simulation results show that energy transmission characteristics of the circuit is in line with the design principles and requirements.② We proposed a control algorithm, which uses output voltage and transformer current feedbacks to improve dynamic response of the controller system, based on the dynamic property of equalization circuit. In order to evaluate response of the controller, equalization converter is a simulated using MATLAB / Simulink. The simulation shows that the control algorithm have a good dynamic response for the change of parameters.③ Finally, integration equalization circuit and the control algorithm proposed above, apply the proposed equilibrium strategy to MATLAB / Simulink, and build the whole system simulation model in the simulation platform, then analysis the results of simulation. The results illustrate equalization network system is effective.In summary, this article studied the circuit topology and control algorithms based on the energy bus based equalization network. Propose an isolated equalization system which realize the equalization of battery system effectively.