Research On Power Control Strategy Of Electric Vehicle Hybrid Power System

The electric vehicle (EV) as a kind of new energy vehicles, with the advantages of low pollution, no emissions, will help to solve the energy and environmental problems. Power supply system is the core part of the EV. Only to improve the power system of energy and power density, longer cycle life, reduce cost, could we make electric cars more widely used and promoted. Under the condition of current technology, a single storage device can’t meet the requirements of power system, so this article mainly researches the hybrid power system of EV, which is composed of supercapacitors and batteries.Firstly, introduce the working principle of the supercapacitors and batteries and the energy storage characteristics of each device. Determine the basic connection mode of hybrid power system through comparing several kinds of common structure and in view of the control strategy of this article. Model the battery, supercapacitor and bi-directional DC/DC converter basing on Advisor (a kind of EV simulation software).Secondly, establish a new control strategy based on supercapacitor state of charge (SOC) of the new control strategy. Analyze the relationship between SOC and EV speed and match the parameters of whole EV, which includes batteries, supercapacitors and load motor. By the contrastive simulation experiment with the traditional control of voltage and current, analyze the improvement of the new control strategy on the performance of EV.Finally, set up the hardware experimental platform of hybrid power system, and mainly accomplish the design of bi-directional DC/DC converter. Test Boost and Buck mode of bi-directional DC/DC converter from the control of voltage and current. Simulate the charge and discharge process when the load changes, and prove the feasibility of the new control strategy.