Research On Position Sensorless Control Of Permanent Magnet Synchronous Motor Equipped With LC Sinusoidal Filter

Voltage-source inverters are widely used as power supply devices for permanent magnet synchronous motors.The rapid switching action of power switching devices would cause large du/dt,which generates negative effects inevitably,such as increasing insulation stress,as well as shaft voltage and shaft current of the motor.In some special industrial applications,such as coal mining transportation,oil field drilling,deep-sea operations,etc,the location of the inverters is far from the motors,and the negative impact will be exacerbated by the long line effect.The output voltage can be converted into sinusoidal waves by installed LC sinusoidal filter between the voltage-source inverter and the permanent magnet synchronous motor,thereby effectively eliminating the negative effects.This dissertation focuses on the research of interior permanent magnet synchronous motor equipped with LC sinusoidal filter.The research can be divided into three aspects: improved performance of the current control loop,position sensorless control strategy and improved phase-locked loop technology.For the unstable operation of the interior permanent magnet synchronous motor equipped with LC sinusoidal filter when adopting the field oriented control,a resonance suppression self-tuning current controller based on active damping was discussed.Firstly,the theoretical analysis of the resonance phenomenon is discussed.Active damping method is introduced to suppress resonance so as to ensure the system stability.By introducing the frequency domain characteristic analysis,the coupling relationship between proportion coefficient,integration coefficient,and active damping coefficient of the current control loop is clarified.At the same time,self-tuning current controller is proposed,which improves the stable and dynamic performance of the current control loop by online optimizing the parameters of the current controller.Considering the increased order of the control system when it comes to the interior permanent magnet synchronous motor equipped with LC sinusoidal filter,the position sensorless control algorithm based on full-order sliding mode observer is proposed and the online estimation strategy of the motor current is designed.As a result,high accuracy observation of motor current,rotational speed and rotor position is achieved without additional sensors.In order to improve the operating performance of the fullorder sliding mode observer,Lyapunov function is designed based on the error state equation of the observer to satisfy stability analysis.In addition,design method of the gain matrix for the full-order sliding mode observer is studied,and an adaptive link between the gain matrix parameters and the motor speed is thereby derived to improve the performance of the sensorless control system at different speeds.Based on the theoretical analysis of the large rotor position error of the traditional quadrature phase-locked loop under the acceleration and deceleration conditions for the motor,an improved quadrature phase-locked loop is constructed.First of all,the main factors for rotor position error of the traditional quadrature phase-locked loop under motor acceleration and deceleration conditions are analyzed.By optimizing control structure and adding the feed-forward loop to the traditional quadrature phase-locked loop,the estimated rotor position angle can be compensated by the improved quadrature phase-locked loop which belongs to Ⅲ type system.Through the frequency domain response analysis of the improved quadrature phase-locked loop,the tuning method of controller parameters is proposed,which effectively reduces the rotor position error under the acceleration and deceleration conditions of the motor and ensures the steadystate performance of the drive system.The correctness of the research was analyzed by using the Simulink platform,and the effectiveness was verified by towing experiment platform which composed of permanent magnet synchronous motor equipped with LC sinusoidal filter.