| The high efficiency and longevity of electricity storage devices are the premise and foundation for hybrid electric vehicles and fuel cell vehicles which have energy saving,environment-friendly advantages. Low battery power, high current,poor performance under low temperature environment and limited cycle life, are seriously hampering the new energy sources such as hybrid vehicles and in-depth development of the market process. The new super capacitor due to energy,cost constraints and other factors can not completely replace the original vehicle battery power. The dissertation is tend to develop the synergic electric system for vehicle based on the "863" project and the related experience. Thought references to home and abroad direction of research and comparative studies, this paper will be nickel-metal hydride batteries and carbon-based coalition, super capacitors - electrical power, using rational allocation and optimal control on the batteries and power Capacitance , to resolve the current single battery's charge and discharge problem. Ensure that meet the performance needs of the vehicle at the same time, maximize the regenerative vehicle braking energy to achieve greater power efficiency, and extend the service life of power systems, which lay the foundation for hybrid vehicles large-scale popularity.This paper tests the power of the system in the charge-discharge characteristics,as a single-board power and the limitations of the performance advantages of a study to determine the composite components in the power supply can meet the technical indicators and power complex to be the rational distribution of the form of research, especially a more comprehensive and in-depth discussions for complex power involved in the design of the components and how to match and control. The paper includes following five aspects:1. Tests and research on composite power characteristics of the components. Choose response to the demand for the use of vehicle performance test method of hybrid vehicles automotive power of a pilot study, and the test results are in a more detailed analysis, the comparison of the advantages and disadvantages of the power used in the automotive environment; for the Car composite power converters use power DC / DC and the characters of performance indicators for the study of and automotive parts based on the use of composite power characteristics determine the selection and layout of components form with the capacity of the battery SOC efficiency and the open-circuit voltage of one-to-one relationship between a pilot study.2. The model and accuracy verification for various components of synergic electric system. Based on test results from components the nickel-metal hydride batteries and super capacitors, analysis the applicability of the model, according to RC cell and simplified models of battery and capacitor described characteristics in the model for the identification of parameters formulated nickel-metal hydride batteries, super capacitors model of experimental verification, through simulation and test data in the course of the voltage curve comparative studies, the power of the components of the composite model for the accuracy of the assessment of the credibility of the model validation and applicability. Predict SOC of the battery model, based on the current integration of various compensation factors battery SOC forecast algorithm, and establish estimation model.3. The research on the design and power parameters matching theoretical of synergic electric system. According to the vehicle configuration and performance requirements, with the cycle run of vehicle condition, we get required performance of vehicle power r, that is, power,energy, as well as a reasonable ratio between the two;in the system , considering the weight, size and cost of project bounded by the conditions of the circumstances, from the point of view of energy and power supply match the components of the battery and capacitor in series monomers, as well as single-volume capacity. For several parameters of the possible result of a match in the Beijing cycle conditions, using life-cycle cost of power as the goal of at least, parameters of synergic electric system has been optimized and the simulation results of the optimization have been analyzed. The conclusion can be a guide to practical engineering.4. Synergic electric system Control Strategy. To increase efficiency and extend battery life, several power control strategy are compared;Logical threshold power control strategies and fuzzy logic control strategy are brought forward. Comparing the two control strategy condition adaptability, use Dynamic Programming algorithm to determine all the power control rates determined on the power of the largest energy-saving vehicle contribution rate. Dynamic Programming algorithm based on the optimal control of the composite results improves the logic threshold power control strategy, and an assessment of control effectiveness has been given. 5. Developed a functional prototype of synergic electric system and test bench, verify the feasibility; Under cycle run conditions, test the correctness of the algorithm, and battery SOC forecast model is estimated for accuracy of the assessment. Based on the above studies, this paper made major progress as follows:1. First, through the test, got the existing advantages and disadvantages of the single car batteries and the super capacitors; classified the disadvantages as the charge and discharge problem. Put forward the synergic electric system, which is composed with the nickel-metal hydride batteries and high-power super capacitor to make up for a single power supply in the power and energy shortage.2. Make use of mature battery RC model for parameter identification and model, through experiment verified battery RC model accuracy of 94 percent or more;3. Secondly, proposed a "push and pull" concept for synergic electric system,guaranteed performance and taked into account the cost of design principles; put forward the ideal power distribution ratio of energy. Due to constraints in engineering and vehicle performance, the various components of the synergic electric system parameters were reasonably matched in the Beijing vehicle life-cycle conditions to make sure the lowest cost. Summed up synergic electric system design theory and that it was the first time in the country.4. From fuel economy of cars, power efficiency and brake energy regenerate there aspects, established the logic threshold control strategies and fuzzy logic control strategy to evaluate the effect of control. Offline Simulation results show that a single battery in the same car on the basis of logic threshold control strategy can increased by 5% and 7% of the vehicle fuel economy of brake energy regenerate; and fuzzy logic control strategy can be further enhanced 3 % of the vehicle fuel economy.5. The adaptability of analysis based on control strategy, put forward the optimal control of the power rates, and established a Dynamic Programming algorithm based on the simplified model of power from the overall perspective; determined vehicle benefits and energy-saving potential with synergic electric system. Established Dynamic Programming optimization algorithm can help designers quickly analyze complex model like synergic electric system, a multinational energy system; understood more thoroughly about the energy saving potential and the technological superiority. Also it needed to develop optimal control of the rate of power supply according to different cycle.6. Through the tests, verified the synergic electric system and realized the prototype control functions; complete the Beijing city cycle test and control the batteries and super capacitors separately to prove the feasibility of the control algorithm; the established battery SOC forecast accuracy of model estimated of 94 percent or more.This paper is about the study of hybrid vehicles and other new energy vehicles. It is the key infrastructure work for further research and large-scale market-oriented. Whit the change of constraints in the works under the condition of different types and performance required by hybrid vehicles synergic electric system, it could provide the design parameters matching principle and control technology, which makes automotive synergic electric system technology to be further deepened.
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