The Research Of ISG Controller For Hybrid-Electric Bus

Nowadays, Automobiles are important vehicles in our society. However, because of the shortage of oil resources all over the world, the air pollution problem in the city caused by tail gas is becoming more and more serious. The invention of ISG (Integrate Starter Generator) is an ideal way to reduceemission and solve the problem of electric power, which will have huge domestic and overseas market. Many experts have predicted that ISG will gradually take the place of traditional starter electrical machine and generator. This new technology will become the criterion of the whole automobile industry and it also can bring good social benefit. The research and development of the ISG system is mainly concerned with twoaspects: 1.The research and development of the Permanent-Magnet Synchronous Motor (PMSM) and the Brushless DC Motor (BLDCM) for ISG system; 2.Corresponding to the ECU system of the whole Vehicle. Because the structure and control theory of the ISG is similar with the direct current dynamo, under the condition where the special generator that applied in ISG system haven not yet been successful, it is reasonable for us to usedirect current dynamo as a temporary substitute. In addition, the single chip of PIC18FXX8 series that integrates PWM module at periphery and CAN communication module, which are convenient for the application of CAN. It has such characteristics as the short period instruction, the strong anti-jamming ability and has many kinds of C languagecompiler. So PIC18F458 single chip is chosen as the central control. The designing of the circuit is to carry through the elementary experiment of electrical machine and offer convenient and experimental data support for the perfection of the program of electric machinery control and intuitionistic operable alternation terrace and the primary experiment of CAN communication. It includes the following aspects: 1.Generator commutation control module and interface; 2.Generator rotate speed module and inerface;3. Upper machine communication module and interface (RS232); 4.CAN communication module and interface 5.keyboard import and module ISG is not an independent system. It is designed for the development of performance of the automobile. So it must be put in the automobile control system and exists as a subsystem. At present, most of automobile ECU system use CAN. In this way, the ISG and CAN are very important. The function of this part is: 1.Convey the power; rotate speed and electric pressure and system parameter of ISG to the center of the automobile; 2.Adjust the system state to satisfy the requests of CPU of master control. For example: To provide exact torque on the basis of the compensatory value,which is sent form the master control CPU,in order to start on invariableness torque .And it is one of the most important research contents of ISG. At present the functions that have been put into practical use include:1.The commutation control for Brushless DC Motor;2.The speed control on open loop and closed loop;3.the intricate keyboard and display usage;4.the elementary experiment of CAN communication. With the progress of the research work, we also find the limitation of PIC18FXX8 in electrical machinery control.1. As ISG, besides the basic function of the control of electrical machine rotate speed, it also should includeinvariableness torque output and the invariableness power control when the speed has beyond the rate value . But at this moment the voltage induced by itself has been higher than the driving voltage. In order to solve this problem, we should use the idea of vector control to deal with magnetic field. That is through the control of drive current to reduce the induction electric current.The operation of vector control is so huge, which demands high speed andoperation ability of the central processor. PIC18FXX8 cannot satisfy it.2.Generating electricity is another important function for ISG. The realization the function of electrical machine...