Research Of Harmonic Suppression Method In Mine Hoist Ac Speed Regulating System

Mine hoist is a kind of large production equipment in coal mine enterprises. It’s working security and stability concerns workers’ safety and the economic benefits of enterprises. With the maturation of AC speed regulation technology, AC speed regulating system has been applied to almost all mine hoists. But the application of AC speed regulation system brings additional harmonic pollution problems to the grid. Aimed at the problem of harmonic pollution coal mining enterprises have adopted many corresponding measures, but they still can’t suppress harmonic spread to the grid and the surrounding area very well. This paper’s main research object is mine hoist AC speed regulation, and based on the power supply network structure launch a harmonic suppression strategy research.In this paper, firstly, the advantages and disadvantages of AC-DC-AC and AC-AC inverter frequency control will be comparatively analyzed in terms of harmonics, then based on the characteristics of mine hoist works, a conclusion can be obtained through the simulation experiment which is that when the mine hoist is working, the change of frequency and load can cause the distortion of voltage of the motor terminal, which affects the power quality of power grid. In view of the mine hoist AC speed regulation system produces harmonics when it is working, this paper begin to study harmonic suppression strategy of the system. Harmonic suppression mainly adopts the method of active filter and passive filter and passive filter consists of passive filter, static reactive compensation device, and static reactive power generator.Through the analysis of the three kinds of passive filter mode, we can know that the performance of static reactive power generator is the most superior, but the high cost is the biggest drawbacks. On the principle of compensation, static reactive power generator is similar with active filter, and active filter not only has the advantages of static reactive power generator but also the cost active filter of is relatively low. So in this paper, passive filter and active filter will combined to restrain the harmonic of mine hoist AC speed regulating system. In this case, active filter can make up for the inadequacy of passive filter in dynamic performance, and passive filter can compensate active filter for which has small capacity. To make the active filter has good performance in the dynamic compensation; we need to stabilize the DC voltage of active filter, so this article uses the voltage difference square parameter discretization of self-adjusting PI control method to control the stability of the DC voltage. In addition, passive filter is easily affected by the power grid impedance change, and may lead to the resonance phenomenon in the grid; in this paper, we adopt the active damping to damping resonance phenomenon. Active damping strategy changed the filter impedance presented mainly by changing the output of the compensation current indirectly. Mainly based on the two methods modal analysis and sensitivity matrix evaluation strategy calculate participation factor active filter suppress the hazards of harmonic wave and network resonance,Based on the principles above, to verify the effectiveness of the proposed strategy we build mine hoist AC speed regulating system, active filter, and coal mine power supply network simulation mode in MATLAB/SIMULINK and finally the hardware and software part of the active filter has been designed. Simulation and experimental results show that, the hybrid active filter combined with the method of modal analysis and sensitivity matrix evaluation strategy calculate participation factor can satisfy the requirement of inhibition of mine hoist harmonic of AC adjustable speed system.