| Switched reluctance motor drive system (SRD) is a kind of novel motor drive system which developed rapidly after DC motor drive system and asynchronous motor variable-frequency speed control system in the 1980’s. Switched reluctance motor (SRM) is a typical mechatronics product, and it has the advantages of simple and solid structure, reliable performance, high efficiency etc. Meanwhile, SRD speed control system which is composed by switched reluctance motor also has many good qualities. Such as high reliability, good performance in speed regulation, plenty of controllable parameters, flexible, large starting torque, high efficiency. Thus, SRD is a very popular research topic in the field of modern electric drive.The most prominent problem of switched reluctance motor is large instantaneous torque ripple. The direct torque control method has been applied in SRM control, for which is not sensitive to motor parameters and has fast torque response, low switching frequency. This thesis has chosen the direct torque control as motor control strategy and compared it to chopping current control method. The results have proved that direct torque control strategy has a better torque ripple suppression effect.First, the mathematical model of switched reluctance motor has been established based on the basic equations of SRM.The basic components and the working principle of SRM also have been introduced. Then this thesis established the linear model and quasi-linear model of SRM respectively, and based on the model, the phase current, phase inductance value and instantaneous torque calculation of SRM have been analyzed.Then two kinds of SRM control methods have been introduced, including direct torque control (DTC) and chopping current control (CCC). In this thesis, the principle of DTC and CCC has been analyzed in detail. After that, the model and simulation of the two schemes have been implemented. Phase current, torque ripple and time from start to rated speed of the two schemes have been compared, and the superiority of SRM DTC can be proved.At last, the experiment part of SRM, including platform design and constructing is introduced. The design part is consist of the measurement circuit of bus voltage, IGBT fault detection circuit and IGBT drive circuit. The main program of control software and the flow of interrupt service subroutine in SR motor speed regulation platform also have been described in this thesis. The experiments contain two parts:single closed-loop experiment with position signal feedback and chopping current control of SRM, the experimental results have been analyzed after the completion of the experiment. |
