| The conventional permanent magnet synchronous motor drive system uses the electrolytic capacitor as the filter energy storage device,and the current harmonic content of the grid side is high.The use of PFC circuits can reduce their grid-side current harmonics and improve their power quality.However,PFC circuits undoubtedly add extra volume and cost to the system.In addition,as the core component of the dc-link link,the electrolytic capacitor has the disadvantages of easy evaporation and low life at high temperature,which reduces the reliability and stability of the motor drive system.Therefore,the electroless capacitor drive system with high stability and good power quality on the grid side has become a hot research topic.However,although the electroless capacitor improves the output power quality of the grid side to a certain extent,the capacity of the film capacitor for storing energy is weak,and the dc-link voltage of the drive system has a large voltage fluctuation,and the system generates a pulsating power twice the frequency of the grid voltage.The motor has a torque and a large pulsation of the speed,which greatly affects the performance of the motor.In order to solve the above problems,and improve the dynamic performance of the motor drive system,it has a certain resistance to load torque disturbance.Based on the analysis of the characteristics of the electroless capacitor system,this paper proposes an electromagnetic torque feedforward control system based on IP control,and adopts the virtual impedance dc-link stability control strategy to effectively improve the robustness of the system against load torque disturbance.The system stability is improved and the motor running performance is improved.The main contents of this paper are as follows:1.The basic structure and classification of permanent magnet synchronous motor,mathematical model under different coordinate systems and several typical vector control techniques are introduced.The advantages and disadvantages of the electroless capacitor motor drive system are described in detail,and the powercharacteristics,especially the influence of the pulsating power on the system and its causes are analyzed.On this basis,the steady state of the motor drive system under the condition of dc-link capacitor voltage fluctuation is analyzed.With dynamic performance.2.Based on the theoretical analysis of the characteristics of the electroless capacitor drive system,a new IP speed controller against load torque disturbance is proposed and its advantages compared with the traditional speed PI controller are analyzed.At the same time,a magnetic chain observer based on PI control is introduced to realize accurate and rapid observation of electromagnetic torque of the motor.The motor electromagnetic torque feedforward control strategy improves the dynamic performance of the electroless capacitor drive system and improves the system's resistance to load torque disturbance.In addition,in order to achieve the system's output AC signal without static tracking,the q-axis current loop control uses a quasi-proportional resonant controller.At the same time,considering the problem of dc-link voltage fluctuation in the electroless capacitor system,a control strategy is proposed to change the virtual impedance of the system to suppress the voltage fluctuation.Finally,the feasibility and effectiveness of the proposed control strategy are verified by simulation.3.On the basis of theoretical analysis and simulation,a non-electrolytic permanent magnet synchronous motor drive experimental platform was built.The experimental platform uses DSP chip TMS320F28335 as the main control device,and realizes the proposed control algorithm by writing software program.Simulation and experimental results show that the control strategy can improve the dynamic performance of the system and improve the stability of motor operation. |
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