Research On Output Side Filter Of Inverter Of Explosion-Proof Integrative Variable-Frequency Motor

In recent years,with the rapid development of AC speed control system,AC variable frequency speed control system with the advantages of large capacity,simple structure,energy saving and other advantages,has gradually replaced the status of DC speed control system.In the process of coal mining,coal mining,transportation and other needs of AC speed control system.AC speed control system is mainly composed of inverter and motor,and now most of the inverter and the motor is divided into two separate systems,and then use a long cable connection.The underground space is limited,the production environment is very bad,not only such AC speed regulation system will account for a larger space,but also may make the power generation and transmission in the process of traveling wave reflection noise voltage of the motor input changes,even up to several times the rated voltage,which adversely affect the safe and stable operation the motor.Therefore,the flameproof frequency conversion speed regulating machine integrates the frequency converter and the electric motor together,so that the volume is small,the weight is lightened,the failure rate is reduced,the electromagnetic interference is reduced,and the utility model is more suitable for the downhole operation.However,the harmonic components of the inverter power supply have a negative impact on the motor to accelerate the insulation aging,reduce the efficiency of the motor,and increase the loss of the motor.At present,the LC passive filter is used to filter the output power of the inverter.The passive filter has the advantages of simple structure,easy maintenance and low cost.However,the existence of LC passive filter can only filter out the specific harmonic.Therefore,in recent years,the use of active power filter in the output side of the inverter is also studied.The active power filter can filter the harmonics in a dynamic way.However,it is difficult to compensate the harmonics of the large capacity load,and the cost is relatively high.Therefore,this paper proposes a hybrid active filter which combines the advantages of passive filter and active filter to filter the output side of the inverter.In this paper,Fushun coal mine motor limited liability company’s newly developed products of flameproof VVVF machine as the background,using MATLAB/Simulink software simulation method of the combination of passive filter and active filter hybrid active power filter for harmonic wave inhibition of inverter power supply.The paper introduces the advantages and current status of AC speed control system,introduces the flameproof VVVFmachine,analyzes the power inverter harmonic generation and generation in the electric motor and harmonic additional loss of motor negative effects,introduced a variety of active filter and passive filter,analyzes the advantages of hybrid active power filter and active power filter by and the passive filter.Through the MATLAB/Simulink software built by 380 V inverter frequency power supply,composed of rectifier transformer,rectifier circuit,boost chopper circuit,filter circuit and inverter circuit,and for each part of the circuit is verified.The system module is set up and simulated by using the practical parameters of the flameproof frequency conversion speed regulating machine.The simulation results are analyzed and the corresponding filter is designed.Finally,the simulation results show that the hybrid active filter,which is composed of active filter and passive filter,can effectively weaken the harmonics of inverter power supply.