Control method of modular interleaved boost converter for SOC balancing in EV

Abstract

This paper proposes control method of Differential Discharge Handling (DDH) modules with state of charge(SOC) balancing between battery modules in Electric Vehicle (EV) system. The DDH modules are composed of battery modules and converter modules. To achieve high efficiency, the diode is replaced by MOSFET to use the synchronous boost converter. In order to reduce the ripple of input/output voltage and current, it uses interleaved method. Interleaved converter operation is analyzed according to switching state by using state space averaging method. In order to design controller of the DDH converter, a control transfer function is obtained by using small signal modeling. The proposed SOC balancing algorithm maintains constant DC-link voltage and increases the utilization rate of the battery modules, as performing the discharge balancing between the modules by handling the discharge amount of the battery modules. Experimental results verify the proposed SOC balancing algorithm.