Research On The Elevator Energy Feedback Device And Its Transient Process

Elevator is an important device which has been widely used in modern society.Elevator will produce large amounts of energy because of the mechanical energy converted into electricity when it works in braking state.Traditional solution is to use resistance to consume this part of the energy,and resistance consumes energy mainly through the cooling mode.This energy consumption on the one hand will cause the elevator control center temperature too high,seriously affecting the safe and reliable operation of the elevator controller,on the other hand will cause the waste of energy.Therefore,by applying the elevator energy feedback device,the energy generated during braking back into the power grid side,largely will avoid the above problems.The energy feedback device for low-voltage experiment model is built in the paper.The low-voltage three-phase power grid is generated by TMS320F2812 DSP processor,and another TMS320F2812 processor is used as main controller of the energy feedback device.And the voltage waveform of the energy feedback device under SVPWM modulation is also analyzed.The main work and the results are as follows.(1)The working principle of three-phase voltage source PWM rectifier is analyzed,and a mathematic model of the PWM rectifier under the dq coordinate system is built.And the voltage regulator and current regulator are built in detail to establish the simulation model structure in the MATLAB simulation software.(2)The energy feedback device unit power factor control through building simulation platform of MATLAB simulation software is achieved.By optimizing the parameters of the PI regulator,it finally realizes the short transient process(three cycles of the grid),and feedback current has no obvious overshoot(less than 20 percent).(3)The energy feedback device is carried on the detailed design,including three phase low voltage power circuit,auxiliary power supply circuit,control circuit,sampling circuit,filter circuit,signal conditioning circuit and protection circuit.The component parameters of each circuit are showed in detail.(4)Using DSP processor TMS320F2812 completes software programming in the programming environment CCS6.0.It includes the main program,ADC sampling subroutine,SVPWM subroutine and interruption subroutine.(5)Finally,a good three-phase low-voltage grid voltage waveform is achieved with the experiment,meeting the requirements of low-voltage network side of the grid.In addition,voltage waveform of feedback devices is obtained in SVPWM with the analyzing of FFT.Phase voltage waveform presents saddle,whose main component is 50 HZ fundamental and third harmonics.Simulation and experimental results show that the elevator energy feedback device adopting SVPWM modulation method can improve the utilization rate of dc bus voltage.By choosing the appropriate filter inductance can improve the feedback current THD indicator.It can improve the transient process through the optimization of controller parameters.