Research On Control Strategies For Hybrid Electric Vehicles

The traditional internal combustion(IC) vehicles bring much convenience to our life, but they also give rise to many problems. Environment pollution and energy shortage caused by the traditional vehicles become more and more obvious, even unforgivable. So, developing a new generation of vehicles which are cleaner and consume less energy becomes an inevitable trend and focus of the world. Because it is practicable, hybrid electric vehicle (HEV) has become one of the main choices.Control strategies for hybrid vehicles are algorithms that choose at each sampling time the power split between the engine and the motor in order to fulfill the demands of saving energy and environment protection.Firstly, after summarizing the main control strategies of HEV, this paper pointed out that the main purpose of the control strategies of HEV is to solve the problem of energy management. Reasonable distributing of power between different sources according to the requirement of the vehicle can save energy and reduce pollution.Secondly, with the help of Advisor, models of the main components of HEV and the methods of whole vehicle simulation are given.Then, taking the parallel HEV as an object, this paper investigated the Electric Assist Control Strategy because of its popularity. Based on the analyzing of the strategy, off-line simulation of the strategy is done, and the control parameters are optimized.At last, to shoot the flaw of the Electric Assistant Control Strategy, the improved Electric Assistant Control Strategy is put out, and its model is built, so is the simulation model of the whole vehicle. Off-line simulation of the improved strategy is done, and the control parameters are optimized. From the comparison of the strategy before and after being improved, it can be concluded that the improved strategy is more suitable for the driving cycles in the city. The improved strategy is more economical when the vehicle must accelerate and decelerate frequently.