| The requirements of the high load, high power electrical equipment quantity is increasing with the expansion of the scale of production of coal mining enterprises. The productivity has been greatly improved of the coal mine, and at the same time, the introduction of electronic power devices bring harmonic pollution to power grid of coal mine. So the coal mine power distribution system of power quality has been seriously damaged. And then, with the development of the level of automation of coal mine, all kinds of automation equipment was introduced,have the higher requirements to the power quality of coal mine. So the analysis and comprehensive governance of the power quality is very necessary.According to the problem of the wide application of the power electronic load caused serious problems in coal mine, the paper puts great emphasis on discussing the characteristics of the ventilator and the hoist, and analysis of several common quality problems in electric power grid of coal mine. and the mode of the hoist system which is the main energy consuming equipment in coal mine has been established and simulated the working process in Simulink. The simulation results show that the DC control system of hoist influenced many aspects in the distribution network of the coal mine. The sinusoidal voltage waveform of the distribution network is destroyed, generates harmonics current and results the voltage waveform distortion. So the hoist is the main harmonic source of the distribution network of coal mine.Because a lot of power quality problems appear at the same time, we need to have the basic unit to comprehensive control of multiple power quality problems. Paper based on analyzing the variety of power quality management methods of the passive filter and the active power filter, and so on. The thesis proposes a method of UPQC into the coal mine to solve power quality problems. Analysis of the structure of the UPQC to three-phase three-wire system. Discusses the two important parts which the detection and control approaches. In the part of detection, discusses the algorithm of pq and p qi ?i based on instantaneous reactive power theory and the harmonic detection algorithm based on the PARK transformation. And combine with the compensation characteristics of UPQC, a kind of new detecting method based on the PARK transformation is presented to eliminate the error caused by phase lock for UPQC. Last,in Matlab software,a model is built about two harmonic detecting methods based on the PARK transformation,and the results of the comparison and analysis are given.In the part of control, existing PWM tracking control strategy of the unified power quality conditioner is researched, and combine with the compensation characteristics of UPQC. To improve the traditional control method to remove the influence between the serial side and parallel side. And then builds a model of UPQC in Matlab, some simulation and the results of the comparison and analysis about the traditional and the new control methods are given.Finally, set up and complete the UPQC experimental circuit with DSP as the core device. And design the hardware circuit and circuit board production in detail. Elaborate the algorithm design idea of software system and related program flow chart. |
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