Development Of Driving Technology And Control System Of Motor Specified For Automobile

Issues about environment protection and energy sources security are focused on the automobile in recent years。Many schemes are proposed for this (for Pure Electric vehicle and Fuel Battery Vehicle),Then the times of a quasi-green vehicle —Hybrid electric vehicle comes about and becomes the focus and hotspot of research. Internal-combustion is still the main power of automobile ,and special battery is used to drive electric motor as auxiliary power in hybrid electric vehicle. Automobile with hybrid power train system improves running mileage of automobile,reduce pollutions when automobile runs at low speed, and also save the potential energy produced when the automobile runs at downhill path and the energy brought when the automobile is running at brake mode. Simultaneously, hybrid power train system will get the saved energy back to battery if its charge is allowed, therefore the goal to save energy has been reached. Motor driving and control system specified for automobile is the very auxiliary system to finish the above task to charge up battery. Motor specified for automobile driving and control is key technology in hybrid electric vehicle. So research on hybrid power train system and motor specified for automobile driving technology and control system is meaningful and important. Motor driving and control system can be classified three types: DC motor with booster to produce chop wave driving system, permanent magnet synchronous motor driving system and AC induction motor driving system. According to the function of motor in hybrid power train system, performance of three types of motor driving system is compared, and then AC induction motor driving system is chose to be motor specified for automobile. The main contributions in this paper are shown below: 1. Rotor Flux Observer The flux observer and parameters estimation algorithms with open loop which based on voltage model and current model are compared and analyzed. The flux observing error of estimating algorithm based on voltage model at low speed is too large that produces bad motor control effect, on the other effect integral's existing reduce system steady ability;while the observer based on current model has better estimating performance than that based on voltage model, but its observing performance become bad when speed goes high. Therefore a novel observer with close loop based on improved voltage model is proposed in this paper which increases system steady performance and parameters estimation,and additionally improved current model with close loop combining with voltage model is made to work at low speed in order to improve the observer's low-speed performance. The rotor flux observing algorithm based on new compounding model works much better than traditional algorithm whenever motor speed runs low or high, as can be seen from SIMULINK results, moreover this algorithm is simple so that it is easy to implement by programming based on DSP. . 2. Estimation of Rotor Speed Observing ability of speed with Speed sensorless algorithm which takes stator current and stator voltage as estimating model is discussed in this paper also. A conclusion can be drew .that it is impossible to observe rotor speed at low speed close to zero speed according to math calculation and theory deducing . So a new model reference adaptive algorithm is proposed in this paper, which reduced the stator reluctance effect coursed by temperature, i.e. the stator reluctance is removed in estimation formula, however EMF error is used to adjust adaptive speed according to PI control law. SIMULINK results proved that this algorithm is satisfied, but there exists problem about PI plus adjusting yet to be solved. 3. Analysis and Compare of Torque Control Technologies Research on driving technologies with stator flux control loop, with rotor flux control loop and with stator flux and torque double close loop are mainly done. It can be proved that torque control algorithm based on stator flux and torque close loop has more advantage than other two algorithms which can be seen from SIMULINK figure. In addition, new integral method through filter which is able to avoid problems caused by integral is described and analyzed in this paper.4. Advance in Timing Driving Technologies Primary running mode of AC induction motor in hybrid electric vehicle is generation mode, and so PWM speed adjusting manner is more important. PWM and PAM adjusting mode both have their strong points and weakness. Motor speed is limited when it goes its up speed limit if PWM control algorithm is used. PAM control manner can regulate current wave when it adjust voltage, and reduce energy spoilage brought by rectifier, also improve efficiency of inverter with strong anti-jamming performance, but its circuit is too complex and too costly to apply widely. Therefore, PWM/PAM is proposed combined with PWM and PAM control idea to overcome the above weakness. It takes full advantage of respective predominance of PWM and PAM technology, so that speed adjusting can be well done whenever adjusting system is in low frequency or in speed limit area by using PWM technology and keep u/f constant in low frequency and using PAM technology when speed reaches stated value, make modulate degree fixed near the max value, and change occupancy ratio through DC booster to improve DC voltage value of inverter then output voltage and speed can be kept pro rata whose area is called PAM area. 5. Control System Design and Research on Dynamic Simulink Experiment Effective driving and control strategies of AC induction motor specified for hybrid electric vehicle (HEV) are given in this paper upon the analysis of working course of auxiliary power unit in different running mode of HEV. Control system principle of AC induction motor is simply set forced. Work manners under electro motion mode and feed-back brake mode when car runs downgrade are analyzed, simultaneously control signals driving IGBT inverter and motor model are given according to different running mode. Finally hardware and software design is particularly described and analyzed, and program flow chart is given also. To sum up, more work and deep research are done both on driving technology of AC induction motor mainly on rotor flux observing algorithms improvement, speed sensorless algorithm and IGBT driving technology, but...