The Analysis And Management Of Power Quality In High-Capacity High-frequency Switching Power Supply

With the rapid development of modern industry, more and more rectifiers were used in the mining industry. These devices generated harmonic, lower the power factor, etc, which seriously affected the power quality of the grid. In recent years, compared with the general rectifiers, High-Frequency Switching Power(HFSP) supplies had smaller size, lighter weight, high efficiency, etc. They gradually replaced the general rectifiers.HFSP is composed with nonlinear devices, so it also can generate harmonics, harmonic treatment is also required. This paper does research on the harmonic and reactive current detection,harmonic current tracking control strategy,DC voltage control and system design of active power filter(APF), etc. This paper also combined with project example, analyses the harmonic and reactive current content of the high-frequency switching power supplies in Copper Co., Ltd. Hefei Crown. Through the practice use, this paper discussed the economic and social benefits by using active power filter (APF).Several commonly used harmonic current detection methods are summarized in the paper. Especially, the ip,iq algorithm and the p,q algorithm have been explained in detail, as well as been pointed out its insufficient. Also, an improved ip,iq algorithm has been described and its advantage has been shown comparing to the above traditional algorithm. In addition, the way of optimizing digital low-pass filter has been discussed in the paper. An optimized digital low-pass filter has been adopted. The simulation results verified that the chose method could solve detection accuracy and real-time property effectively.Several general current tracking control strategies are concluded in the paper. Through analyzing, the triangular wave comparison mode is found to display a better performance than the other two control strategies. Thus, triangular wave comparison control tracking strategy has been chose. This paper uses Fuzzy-PI control method, this method make APF can track the target harmonic current and fast dynamic response speed.DC voltage control was analyzed and its principle has been illustrated. Moreover, problems such as the grid, inductance and capacitance energy exchange, harmonic doing work or not also with the feasibility of the DC voltage control, which have been validated by simulation, have been discussed. The simulation results proved the rationality of DC voltage control principle, which showed DC side voltage could reach the setting value fast.Beside analysising the detection and control strategy, this paper establishes the simulation of the whole system to manage harmonic and reactive current, the simulation results proved the validity of the involved method, which could not only reduce harmonic distortion rate in the grid, but also improve the power factor, reaching governance requirements.Power quality adjustment device design has been studied in the paper. In addition, main circuit design, control system design and electromagnetic interference problem have been explained in detail. Voltage-type active inverter, DC Bus Capacitor, output smoothing reactor, power module thermal design and buffer circuit design are included in main circuit while control system design includes hardware and software part. Electromagnetic interference design consists of its producing cause and its solution.Finally, combined with the harmonic elimination and reactive power compensation project in Hefei Copper Co., LTD. Through the practical engineering application, a conclusion was drawn that input of Active Power Filter (APF) could bring about huge economic and social benefits.