Research On The Optimization Of A Power-Split Hybrid Electric Vehicle

Hybrid electric vehicle (HEV) is a new kind of vehicles, which is designed for energy depletion and environmental pollution problems. HEV is different from the conventional vehicle, since it has more than two kinds of power source, and electrical energy is one among them. According to different structures, there are three kinds of HEV:series mode, parallel mode, and power-split mode. Comparing to the series and parallel modes, the power split hybrid is more complicated, but more flexible. The key components of the power split HEV is the planetary gear, which connects the engine, generator and motor. Through the planetary gear, part of energy from ICE is shunted onto the generator and the ring gear. The energy shunting onto the generator is converted into electrical energy stored in a battery, then it is converted into mechanical energy for driving. Such power flow is the same as the series mode. Another part of energy from ICE is shunted onto the ring gear for driving. This is similar to the parallel mode.In this paper, two rule-based strategies for HEV are presented. One is designed to reduce the fuel consumption. By using the genetic algorithm, the optimal parameters of the strategy are given. The result demonstrates that the strategy may lead many charging processes. Since the more charging processes, the shorter life the battery will left, it is necessary for us to take the charging times under consideration. A bi-objective optimization model is developed. Then genetic algorithm is applied to get Pareto optimal solutions of the problem.