Study On The Control Strategy And Industrial Device Of The Unified Power Quality Conditioner

With the development of science and technology, the sensitivity of modern industrial, commercial and residential electrical equipment to power characteristics increases annually and their requirements of power quality are also continuously improved. The unified power quality conditioner (UPQC) with excellent performance can solve many power quality problems, and can also compensate the reactive power of the load. As a result, UPQC is more suitable for dealing with several complicated power quality problems simultaneously. UPQC control strategies and industrial device are studied in this thesis.Firstly, based on domestic and oversea research results, the analysis of the distribution network of industrial park for UPQC application is carried out. According to the requirements to the power quality, the technical features and functions of the three-phase three-wire UPQC are determined.Secondly, the operating principle and mode of the three-phase three-wire UPQC are elaborated. Based on the topology of the main circuit, the low frequency model and small signal model of three-phase three-wire UPQC series converter, parallel converter and DC side are established respectively in the three-phase static coordinate and DQ rotating coordinate, besides the relationship between the UPQC DC voltage and the active current of parallel converter is discussed. According to the control requirement, the main circuit topology and the primary device parameters of UPQC are designed.Based on the research results of UPQC low frequency model and small signal model, the detection method of the compensation component of UPQC series and parallel converter is designed. According to requirements of compensation and response speed of the UPQC, the corresponding control strategies are designed. The problem of resonance between the RLC filter and the UPQC converter is also analyzed, damping control strategy to suppress the resonance is also designed, and the validity of the strategy is verified by simulation.At last, based on DSP physical controller and RTDS digital/analog mixed simulation platform, the effectiveness of the proposed control strategies are verified by simulation experiments and the technical plan of 10kV/1MVA UPQC is designed according to the experiments. The compensation function of the UPQC industrial device is tested to verify its validity relying on the voltage and current disturbance device. The experimental results were compared with the results of the simulation experiments. At present, the device has been put into operation in one enterprise in Beijing, and the operation effect is good, the technical indexes can meet the design requirements.