文献出处:Pollet G. The research of electric car charging system and controller [J]. Electrochimica Acta, 2015, 5(3): 235-249.原文The research of electric car charging system and controllerPollet GAbstractThis paper puts forward the whole bridge main circuit topology and PWM control method effectively improves the reliability of the charging system and efficiency. Put forward and realized based on digital signal processing chip controller circuit intelligent PI control algorithm and variable parameters, significantly improve the control precision of the charging system voltage, current and response characteristics. Double proposes a CAN bus and RS - 485 bus communication network, realized the distributed control of the process of charging, the charging operation is flexible and reliable. Due to be able to provide a communication interface to battery management system and algorithm, charging system according to the state change of battery charging mode, optimizing the charging mode. The success of the charging system has important theoretical significance and engineering value. Keywords: Electric cars; Charging system, PWM, Intelligent PI, Distributed control 1 IntroductionElectric car, it is all or part of the electric drive system of power car, compared with conventional cars powered by gasoline as, electric cars in such aspects as environmental protection, clean, energy-saving occupy obvious advantages. Now each big international automobile manufacturer have invested a lot of money and manpower to electric car research and development, a variety of the electric car prototype appeared frequently, some have reached high industrialization scale. Now the development of the electric car industry has formed a hybrid vehicles, pure battery-powered electric vehicles (electric cars) and three main direction of fuel cell electric vehicles. Pure electric vehicle itself is not harmful gas emissions, can make full use of surplus power in the evening, improve the efficiency of energy utilization, and improve the economic benefit. Pure electric vehicles completely eliminateemissions of the vehicle running, fully use of secondary energy electricity, in line with the energy sustainable utilization strategy, along with the progress of the technical level, the pure electric vehicles has a broad development prospects. But at present, the development of the battery and charging system can't satisfy the requirement of electric cars, there are some theoretical and technical problems have yet to be research, serious lack of relevant standards and norms, has become the bottleneck of affecting the development of electric vehicles.2 The current situation of the electric vehicle charging systemAt the beginning of last century, as the secondary battery research is successful, and matching charging system arises at the historic moment. The charging system using the conventional charging method, which is USES small current for a long time to recharge battery. This way of charge due to the charging time is too long, can not meet the requirement of the electric cars and so on, the demand of the quick charge. Widely at home and abroad to carry out the study of fast charging system. Fast charging system produce roughly experienced three stages of development:(l) Groping stageIs the earliest in the 50 s of the last century, the United States as a result of the need of military, began to study fast charging technology, made the metal rectifying shape fast charging system, for 6 to 24 v lead-acid battery quick charging, the weight of 40 kg, have fast, medium and slow three charging modes.(2) The theory research stage1967 U.S. troops (Mas) have bubbles in the process of charging is studied, find the reason and law of gas, on the premise of minimum gas rate and find out the maximum charging current of battery can accept and acceptable charging current curve, discusses the theory of quick charge battery, and on the basis of practice, put forward the basic rules of quick charge battery.(3) The practical application stageMcCulloch electronic companies in the United States in 1970 made the lead-acid battery quick charging system, for 500A to 190AH battery charging current, and in 1200A discharge to deal with the polarization current for short periods of time, theresults 30 minutes to put the battery is good. In addition to the United States, such as Japan, other countries such as Britain, France, Germany, the former Soviet Union also has different degree of development in rapid charging technology. Britain's associated company invented "TEC total energy intelligent charging control technology" and its control system, effectively control the powder charging when the amount of energy needed, overcome existing corona charging system and friction type charging system caused various problems, to solve the "Faraday shielding effect" and "reverse ionization effect" and so on.At present the batteries of electric cars in use process, because of the limitation of the voltage of the power battery energy and need to adopt more battery in series combination, and power battery characteristics of highly nonlinear, individual difference is very big, therefore become the electric car battery management system, a necessary device. The most basic function of BMS is to monitor the working state of the battery (voltage, current and temperature of the battery), prediction of power battery (SOC) of battery capacity, battery management to avoid over discharge, overcharge, overheating and serious imbalance between monomer battery voltages, maximize battery storage capacity and cycle life.Current of the electric vehicle charging system is not very good with a serious defect currently has been relatively mature and supporting the use of on-board BMS system, charging system is either not provide communication interface with BMS, or communication interface is not compatible with popular now BMS interface. BMS system has the most comprehensive, full of battery state of real-time data, if you can provide the charging system and its communication interface, can fundamentally solve the current charging system in the process of charging the battery status change resulting in without understanding the state of the battery charged blindly charging, thus reduce battery life.In addition, as the core of the electric vehicle charging system, the existing charging controller, the control process are mostly based on analog signal processing, and its control structure is a centralized control structure. The traditional charging system boundary is not clear, complex structure and each subsystem is unitized degreeis very low. Its applied electromagnetic environment, all kinds of high frequency signals could easily lead to serious interference of microcomputer control charging system failure. In the past, often using analog signal for each signal transmission is between the control systems. Various kinds of interference signal into analog signals, it is easy to lead to failure of the control system, its structure and the process may not apply to the requirement of the distributed control and the whole process of the digital processing requirements.3 The function of the electric vehicle charging system requirementsThe charging system in addition to providing communication interface with BMS, received by the BMS battery status parameters of transfer function, extract energy from power supply and charging system is passed to the battery in the right way, so as to set up between power supply and battery power conversion interface. Charging system is usually performed by the power conversion unit and process control of controller. The basic properties of the charging system requirements include the following:Security: electric vehicle charging, how to ensure that personnel's personal safety and the safety of the battery is very important. Easy to use: charging system should have high intelligence, operators don't need too much intervention in the charging process. Cost economy: economic and cheap charging system helps to reduce the cost of the whole electric cars, improve operation efficiency, and promote the commercialization of electric vehicles. High efficiency: efficiency is one of the most important requirements for modern charging system; the efficiency of the energy efficiency of high and low for the electric car has a huge impact. Low pollution to the power supply: the power electronic technology of the charging system is a kind of highly nonlinear devices, will produce harmful to the supply network and other electrical equipment of the harmonic pollution, moreover, because of the charging system power factor is low, the charging system load increases, its effect on the supply network also not allow to ignore.4 EV charging method4.1 Constant current chargingIn the whole process of charging and is always with constant current for rechargeable battery. In this way, to ensure that in the later stages of charging without a lot of gas, therefore can only use small current charging, so need a long time, the charging method has the advantage of simple operation, the current is too small, but in the beginning in the late charge and charging current is too large, charging time is long.4.2 Constant voltage chargingEarly charging current is quite large, as the charge and current decreases. For more battery discharge, the initial charging current is too large in order to protect cells from damage, at the beginning of the charging to limited flow measures to avoid the charging current is too large. Compared with constant current charging, the battery is not easy to calculate.4.3 Constant voltage charging current limitingTo remedy constant-voltage charging shortcomings, is widely used in constant voltage current limiting method. Set the maximum charging current, at the beginning of the charge, when the current exceeds the limit of flow value, with the current limiting value, when the current less than the current limit value, constant voltage charging. Thus automatically adjust the charging current, does not exceed a certain limit, the charging current is controlled in the early.4.4 Constant voltage charge after constant currentThis method is a combination of constant current charging and constant voltage charge, the previous constant current charging and accounting period of constant voltage charging way, on the one hand to avoid the constant voltage charging current is too large, in the early late again on the other hand to avoid the constant current charging phenomenon.4.5 Charge attenuationIn the process of charging, with the increase of voltage of the battery, charging current attenuation of charging method gradually. This is a kind of ideal charging method; charge saves time and prevents the sulfuric acid stratification and the plate vulcanizing. But this charging method implementation requires more complex control,compared with the constant current charging; the charging amount is not easy to estimate. Due to the battery and nonlinear dispersion, complexity, the problems in the process of charging, the battery charging has become a more complex issue. The traditional charging method is used to charging very troublesome, because often be charging for 10 hours, and in the process of charging must be manned. Quick charge is the problem to be solved in the process of charging current control, in the process of charging, if the charging current is not enough, to reach the purpose of quick charge. If the charging current is too large and will cause a large number of precipitation of gas, electrolyte temperature will rise quickly, easy to cause the battery plate is damaged, shorten the battery life. Also in the process of charging battery monomer battery consistency of difference, this factor must be fully considered.译文电动汽车充电系统及控制器研究Pollet G摘要本文提出了全桥的主电路拓扑结构和PWM的控制手段，有效的提高了充电系统的可靠性和效率。