Power Load Of Four-quadrant Voltage Inverter Applied Research

In modern era, the rapid development of industry, advanced technology has beendeveloped rapidly, attendant high-tech industry has entered a period of rapid development.Among them, the development of frequency control technology is particularly prominent,with the advent of the four-quadrant voltage inverter as well as its application in a varietyof high-power load, making the frequency control field has been further developed.Effective use of four-quadrant inverter can better achieve energy saving era of China’senvironmental protection in the offing.For nearly three decades, the field of frequency control is generally used forconventional AC variable speed AC drives, which in many ways to facilitate the governorhas a significant advantage: its stable performance, relatively simple structure, largestarting torque and speed wide range of speed control in accuracy, speed, and adjust theenergy saving aspects have a very good effect. As the frequency control technology iswidely used in the industry today, the development of inverter technology becomes moreurgent. Inverter technology is not mature enough in time, the traditional inverter aregenerally chosen to form a diode rectifier bridge to achieve the AC current to DCconversion, finally, turn the DC current through the inverter technology convertsalternating current to drive the load operation, AC to DC and then to achieve cross-current conversion process. However, due to the three-phase inverter-controlled rectifiercircuit this tradition is made using a diode, which can transport electrical energy from thegrid side to the motor converts electrical energy into mechanical energy, and can not beturned into electrical energy to mechanical energy transfer to the power supply, so it cannot achieve the two-way flow of energy, so this can only work in the electric state drive,which is called the two-quadrant inverter. On some motor feedback system energy needs,such as mine hoists, elevators, centrifuges and other high-load operation of occasions, thetraditional two-quadrant diode rectifier bridge inverter grid will be serious harmonicpollution. In recent years, new insulated gate bipolar transistors-IGBT (Insulated GateBipolar Transistor) technology generation and pulse width modulation-PWM (Pulse Width Modulation) development, to produce a new type of high-voltage inverter-fourquadrant high pressure inverter. With the traditional two-quadrant inverter is different, thenew four-quadrant inverter using insulated gate bipolar transistors-IGBT rectifier bridgeto do, because the IGBT power modules to take advantage of high-speed computingpower of the DSP generates the PWM control pulse, so we in a four-quadrant voltageinverter in the process both to adjust the input power factor, reduce energy diode bridgerectifier harmonic pollution, but also can be generated by the motor to the reactionaryprocess back to the grid, thus truly two-way flow of energy.This study around four quadrant voltage inverter applications in high-load industrialareas were expanded, mainly to seize a four-quadrant voltage inverter topology featureson the analysis, the first of the four-quadrant structure and working principle of theinverter a detailed introduction, describes the electrical energy conversion and flowdirection between running four quadrants and mechanical energy and electrical energy,which details the four-quadrant inverter compared with the traditional two-quadrantinverter, which is technically in the frequency breakthrough and its advantages inindustrial applications. Further, the motor running in the combined four quadrantsfrequency analysis performed in the course of the four-quadrant drive motor is running,the flow direction of the energy system. Secondly, the project mainly on technical issuesfour-quadrant inverter drive motor to work in coal power load inclined hoisting systemencountered in the process: In the inclined mine hoisting system, the motor speed controlis generally used in a string wound rotor resistance method, so that in the coal mine hoistupgrade process: elevator descent, potential energy into kinetic energy of the motor themotor in the fourth quadrant is active reverse power, then slip the power consumed in theform of heat on the resistance, resulting in a lot of wasted energy; addition, in the courseof the inverter, AC contactor require frequent switching, after long hours of work, themain contact is easier to melt, the equipment often fails. In order to solve the aboveproblems, this experiment in combining four-quadrant voltage inverter with potentialapplications where the load characteristic advantages, research new ways to reduce thepower consumption of the energy difference between the turn. Therefore, in this study the application on the basis of four-quadrant inverter power adds a new speed control system,which does not require the resistor string for debugging, to avoid waste of energy.Meanwhile, in order to ensure that when the speed control system failure can quicklyswitch to the original system to run, so this test is to retain the original electrical controlsystem debug mode and series resistance.By the results of this study we can see: After using the above method, compared withthe previous series resistor speed control, slip power consumed in the form of heatresistance on the part of the energy that can be fed back to the power grid, sub-effectivemanner to achieve a two-way flow of energy, effectively saving energy. However, in thisexperiment, there are some drawbacks: For example: Because the rectifier and inverterare not well coordinated, so the whole control system can not be achieved in accordancewith the laws of intermittent operation characteristics of the motor is running, the problemneeds to be improved follow-up study.