Research On Some Special Problems About Vehical Used ISAD System Based On Switched Reluctance Motor

ISAD namely is Integrated Starter Alternator Damper system, which is a new device applied in vehicle equipment recently. The ISAD system can increase power generation capacity and output torque, decrease the fuel consumption and emission, enhance driving comfort by reducing the engine torque ripple. Switched Reluctance Machine (SRM) is a result combied with the motor technology, morden power electronics technology and microprocessor control technology. It's features like simple and firm structure, low costs, high fault-tolerance capability, high torque output with low speed, etc, as makes SRM one of the best choise for ISAD system mortor.Taking background of SRM applied in ISAD for HEV, this paper particularly discuses ISAD active damping working conditions and an approach detecting rotor position without pision sensor based on SRM. Together with machmatics modeling of SRM, it analyses operation characteristics of SRM when electrically driven and generating power. According to the performance requirement of ISAD, control strategies of SRM in damper mode are presented and fuzzy PID controll are designed respectively; the ISAD system is digital verified on MATLAB / Simulink toolbox, furthermore the SRM-based ISAD experimental platform is established, the control software is also designed. An approach detecting rotor position based on loo-up table method of two-phase pulses inspiriting is presented with current state of sensorless technology introduced, That is, inject narrow voltage pulses into two non-conducting phases of SRM and detect the corresponding currents. So we can get the position information from the relationship of the rotor position, stator winding inductance and the corresponding currents.In this paper we also studied the frequency of the injected voltage pulses and the methods of measuring the motor speed.This methods got the position information by detecting the variation trends of the corresponding current instead of many a complicated calculation, which not only eliminates the detection errors,but also decreases the effects of valtage fluctuation and load variation,and then strengthens the stability and robustness.However,when the motor speed is high,the flux will be saturated and the inductance between phases can not be neglected,which leed to the invalidation of this methods.So,we can only use this sensorless methods to detect the rotor position in start-up stage. According to the measured data tables is made to calculate the rotor position; the use of this method in the initial rotor position detection is also researched.In this paper, experiments are done on an platform with a 12/10 SRM as the control object and a controller based on DSP+CPLD. The experimental results show that the approach of two-phase pulses inspiriting rotor position detecting without position sensor can mate the control requerments of SRM at low speed. The simulation and the experimental results based on system of SRM ISAD prove that the ISAD system in damping state can reduce engine torque ripple at idling state.