Nonlinear Modeling And Control System Research Of Switched Reluctance Motor

Switched Reluctance Motor (SRM) has advantages of single rugged structure, excellentspeed adjusting performance and high reliability. Because of its new suddenly rises in modernelectrical drive, it has attracted much attention. But its unique double salient structure andworking methods leads to the new model having strong nonlinear characteristics. Itsperformance and the control mode are significantly different to the traditional motor, whichwill cause serious torque ripple. But its double salient poles structure leads to serious torqueripple. The thesis researched the method of improving switched reluctance motor’s torqueperformance from the mathematical modeling and the actual control.The accurate mathematical model establishment of switched reluctance motor is thebasis for high-performance analysis and control, but also one of the important methods tosuppress torque ripple. On mathematical modeling, the thesis analyzed the characteristics ofswitched reluctance motor flux, introduced the flux detection and calculation methods, anddesigned the corresponding DSP detection methods. Base on existing flux data, it analyzedthe nonlinear modeling of SRM, and made the corresponding modeling simulation. In termsof actual control, it presented the control thought of direct torque control (DTC) method,derived the instantaneous flux and torque equations of four-phase SRM, discussed the spacevoltage vector and corresponding switches table under the DTC method and made thecomparing simulation experiment. Simulation results show that the DTC method caneffectively suppress torque ripple. After adding torque detection with nonlinear modeling,which provided a theoretical basis for the replacement of expensive torque sensor,suppression was significantly improved.The hardware and software design work of SRM speed adjusting system were finished.The circuit used DSP TMS320F2812as core controller, including main control module,power converter, current, voltage detection and a position detection circuit. With C language,it wrote the current chopping startup, direct torque control and associated subroutines. The experiment achieved switched reluctance motor’s startup using two-phase current chopmethod, which has laid a good foundation for further work.