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Research Of Switched Reluctance Drive System For In-Wheel Driving Electric Vehicle

Posted on:2008-04-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:J W LuoFull Text:PDF
GTID:1102360272966801Subject:Motor and electrical appliances
Abstract/Summary:PDF Full Text Request
Compared with signal motor drive electric vehicle (EV), in-wheel motor drive EV will be a tendency of development because of its unique characters of chassis structure and vehicle manipulation. Motor drive system is one of three key parts of EV. There are diverse types of motor drive system with difference performance, Switched Reluctance Motor (SRM) is preferred because of its simple robust structure and outstanding performance. After 20 years study and development, SRM is succeed in application in EV domain, and is beneficial to economy and environment. This dissertation is devoted to the fundamental and experimental research of in-wheel SRM drive system, and is composed of following seven aspects.First of all, the development history and the critical techniques of electric vehicle are discussed, and the characters of diverse motor drive system are compared. As a promising candidate, the newest evolution of SRM and its merits and demerits for EV usage are particularly presented. The advantage and up to date development of in-wheel motor drive EV are summarized. Combining the advantages of in-wheel motor drive system and SRM, the research on SRM in-wheel motor drive system is becoming necessary.By analyzing vehicle theory and technique, the essence of vehicle manipulation is indicated, i.e. controlling force between road surface and tires (include traction force and brake force). By properly controlling the force, some advanced vehicle manipulation strategies, such as traction control system (TCS) and vehicle stability control (VSC), can be fulfilled. For in-wheel motor drive EV, every propelling wheel has its own motor drive system, the principal character in-wheel motor drive system should have is average torque closed-loop control.To overcome the shortcoming of conventional torque control of SRM and fulfill closed-loop average torque control for SRM more precisely, a novel torque control strategy is presented. By placing auxiliary gauge winding on the stator pole and adopting hardware integrator, the flux linkage is measured. Utilizing flux linkage and phase current, the output electromagnetism torque can be calculated. Synthesizing traditional CCC and APC mode, a multiparameter (phase current hysteretic threshold i ref, turn-on angleθon and extinguish angleθext) adjustment algorithm is adopted. i ref is used to decrease torque error by PID controller, meanwhileθon is used to minimize the peak and root-mean-square value of phase current, andθext is used to reduce vibration and acoustic noise of motor. A method based on flux linkage balance to control extinguish angleθext is presented in detail. Simulation software MATLAB/Simulink is used to validate the torque control strategy.To evaluate flux linkage measurement, flux linkage of phase winding and gauge winding with different turns and layout are calculated respectively using FEM software ANSYS 7.0, from calculation results of relative error the optimizing layout of gauge winding is find out. There are two connecting mode for three-phase SRM, i.e. NNNSSS and NSNSNS. By analyzing magnetic field distribution, calculating inductance matrix and experimental test, NSNSNS is proved to be a good connecting mode, which has virtue of working consistently and high torque estimation accuracy. The error analysis of hardware integrator is executed, low noise high precision operational amplifier OP-27 is precise enough for SRM application.SRM's generator operation mode is very important for EV application. Compared with SRM, this dissertation contrastively discusses the fundamental theory and characters, torque estimation, current hysteresis control and angle control of Switched Reluctance Generator (SRG). A method based on flux linkage balance to control extinguish angleθextG is presented in detail. For the special uncontrollable phase current, this dissertation presents the mechanism and the solution. Using simulation software MATLAB/Simulink validates the braking torque closed loop control strategy.A SRM torque control experimental facility is established, and a series of experimental research are conducted to validate the proposed torque control strategies. Hardware implementation of a SRM controller is achieved using Texas Instrument's TMS320LF2407A Digital Signal Processor (DSP) and some peripheral devices. The converter topology is asymmetric half-bridge circuit, power device is FUJI's IGBT 2MBI100-060L. To achieve generator (braking) test, a special high-frequency loading device is designed, which has the ability of regulating voltage. Correcting circuit is made for hardware integrator. Experimental items include torque-rotational speed character, acceleration/deceleration character, torque stability character, torque step response character and motor/generator conversion character. From experimental results, the torque control strategy presented in this dissertation is thus proved to be effective, which has advantages of high precision and fast dynamic response.To improve the performance of switched reluctance motor (SRM) drives, some advanced control strategies have been proposed, such as current or flux linkage profile control. To achieve these strategies the motor phase current or phase flux linkage should be controlled precisely. All these require increasing the switching frequency of converter to increase dynamic response speed. However, higher switching frequency may cause higher switching losses, and thus higher Electro-Magnetic Interference (EMI) and lower overall efficiency. The use of soft-switching techniques in converter can resolve these issues. In this chapter a brand new soft-switching converter for SRM is presented, which has advantages of all Resonant Switch converter (RS), Resonant dc Link converter (RDCL) and Pulse Width Modulation (PWM). The addition of external commutating devices to conventional asymmetric bridge converter for SRM achieves the soft-switching of power devices. The conditions of soft switching are deduced and a practical design consideration is given. Finally, detailed simulation study of the complete system is presented and validated with experimental results.
Keywords/Search Tags:In-Wheel Motor Drive System, Switched Reluctance Motor (SRM), Torque Control, Flux Linkage Measurement, Soft-Switching Converter
PDF Full Text Request
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