Scalar Control Strategy Of Permanent Magnet Synchronous Motor Based On Dual Sliding Mode And Proportional Integral Controller

The permanent magnet synchronous machines(PMSMs)has the advantages of easy control techniques,better power density,better efficiency,better steady-state starting torque,robustness,low noise and low inertia.PMSMs have been widely used in various industrial applications,such as electric vehicles and traction systems.The development of power electronics and motor control theory is widely used in large-scale research on speed control of the synchronous motor.This thesis presents the mathematical model and a novel control strategy of PMSMs.For PMSMs,the widely used control methods are field-oriented control,direct torque control,constant V/f control,etc.These methods can be divided into two categories scalar control and vector control.This thesis explicitly discusses the speed control,using the scalar(V/Hz)control method.Because of its advantages such as low cost,simplicity and easy implementation.The response is better and accurate in closed-loop compared with open-loop control,which is nowadays the most commonly used speed control method.In consideration of these advantages,the scalar control method is a good choice for pumps,fans and compressors which do not require high dynamics for high efficiency and energy saving.The multilevel inverter(MLI)has been applied to drive PMSMs;the input of the inverter is DC which is converted to three-phase AC by using pulse width modulation(PWM).The multilevel inverter has a lot of advantage over three-level inverter such as higher efficacy,higher output power,lower harmonic content and lower dv/dt stress.Modulation of MLI is based on space-vector pulse width modulation(SVPWM)and sinusoidal pulse width modulation(SPWM).SPWM is classified into phase shift(PS),phase disposition(PD),phase opposition disposition(POD)and alternative phase opposition disposition(APOD).The modulation voltages provide the output voltage with a variable amplitude as well as frequency.These different kinds of modulation schemes are done.And comparing all of these,SVPWM is the best choice for the given proposed model.By further research study,Scalar control method is used to control the speed of permanent magnet synchronous motor with a closed-loop along with feedback controllers.For the proposed model,two types of controller are used,which is proportional-integral(PI)and dual sliding mode proportional-integral(DSM-PI)controller.Dual sliding mode proportionalintegral can improve performance and avoid the scattering compared as PI controller as well as traditional sliding mode proportional-integral controller.Besides,DSM-PI have good results such as robustness,settlement time,fast speed response,improve efficiency,lower transient and improve stability.The whole model of scalar control of permanent magnet synchronous motor is simulated in MATLAB/Simulink library.Simulations and its results are shown to confirm the concept of the proposed model.