Elevator Energy Feedback Technology And Research

Nowadays the problem of energy shortage is troubling the countries all over the world.The development of elevator energy saving technology has been attached importance to by the state and supported by the policy.Throughout the development of elevator energy saving technology,energy feedback technology has the most potential,and its energy saving performance still has a lot of room for improvement and has research value.Therefore,this paper USES the existing inverter technology to control the elevator energy feedback system,which can feed the electricity stored in the side capacitance of the dc bus back to the power grid and achieve the purpose of energy saving.This paper studies the working principle of the elevator energy feedback system,and then completes the design of the energy feedback system,which is mainly composed of dc bus voltage and current detection unit,drive unit,inverter circuit unit,main control unit,grid synchronous detection unit and protection circuit unit.In this paper,a dc bus voltage and current detection unit composed of hysteresis comparison circuit is designed.On the one hand,it can prevent the energy feedback system from starting and stopping too frequently;on the other hand,it can realize the over-current protection and improve the stability of the system.In the drive unit in this paper,first to decouple the mathematical model of energy feedback system analysis,to ensure that the power factor of system approach in 1,again USES the three-phase phase-locked loop control strategy,cooperate with power grid synchronization detection unit,accurate,real-time tracking of three-phase voltage phase Angle,make the output voltage phase with grid voltage,frequency and amplitude keeps synchronous relationship.Aiming at the inevitable dead zone in the inverter circuit unit,a dead zone compensation control strategy is designed to ensure that there will be no straight-through short-circuit phenomenon when the switch is on and off.Therefore,it can effectively reduce the phase deviation of the output voltage,reduce the harmonic distortion and improve the stability of the system.In order to further restrain harmonic interference,the basic conditions of grid connection are satisfied.In this paper,the inverter control technology in the main control unit is studied in depth,and the characteristics of different control algorithms are compared to find a more suitable control method for the elevator energy feedback system.After comparing a variety of control algorithms,SPWM and SVPWM control algorithms are adopted in this paper for modeling by MATLAB simulation software.Through Fourier analysis of simulation results,the influence of carrier ratio and modulation on harmonic is studied,which verifies that SVPWM control method is more suitable for elevator energy feedback system.According to the shortcomings of SVPWM control,this paper proposes a SVPWM control method based on modulation function,which can reduce the amount of calculation while considering its advantages.Finally,it is verified by simulation analysis.