Study On Control Strategy For HAPF Based On Adaptive Prediction

With the development of power electronic technologies, more and more power electronic appliances are widely used to industry, which result inevitably in serious harmonic pollutions and passive power wastage. Then the problem of how to suppress harmonic current and compensate reactive power is concerned by power users and electric power companies.Industrial users commonly use passive power filter (PPF) to deal with harmonic pollutions and passive currents. But PPF has some disadvantages that are not to be overcome, such as the design of PPF depending on topological parameters, having larger size and bringing resonance for some harmonic, etc. HAPF examines and compensates the harmonic current and the voltage in the electrical network. Now active power filter (HAPF) has been an important way to solve harmonic pollutions, and progresse has been got in this area. But some opinions from power users and electric power companies indicated that the cost of HAPF was too high. HAPF needs a large-capacity power inverter that bears the voltage of network-side and goes through all the harmonic currents and passive currents for counteracting harmonics and reactive power. Resonant Injection Type Hybrid Active Power Filter (HAPF), which decreasing the capacity of inverter for reducing the cost of HAPF, is presented by some researchers. HAPF overcomes the shortages of PPF, and will be popular in future. In this thesis, the topological structure of Resonant Injection Type Hybrid Active Power Filter (HAPF) is adopted.In this paper, the Circuit topology, method of Harmonic Detection and control of the HAPF are particularly introduced, and also verify the validity of the selected control strategy after formula illations.The function of HAPF is to achieve accurate real-time harmonic current compensation, the key lies in accurate real-time detection of harmonic current which should be compensated. Due to delay effect based on digital control, this paper proposes adaptive prediction algorithm, and verifies feasibility via simulation.. And use MATLAB software to simulate by computer, it establish elementary base for the study of actual theory.Based on the core of TMS320F2407, established the high speed digital signal processing control platform.Designed system control circuit of shunt active power filter,put forward block diagram of the system control software. The HAPF system's hardware and software design was founded on DSP. Based on TMS320F2407, this article successfully designed One-Phase PWM Inverter(2kVA). Then it proceeds with relative modulation and testing, and analysis experimental data in the end. This paper applies One-Phase PWM Inverter to the prototype of HAPF.The following research work has been done:1. The reasons and harm of the harmonics problem are discussed and actual methods are given to solve it.2. The principium of power filters is introduced in detail.3. A second-order math model is built due to HAPF.4. A new adaptive prediction of suppressing harmonic is presented in detail, and this method has strong robustness to various disturbances. The simulation results show the validity and the performance of the unified compensative method.5. Grid interconnection and running problems of HAPF are simulated, and this is actual meaning.6. Designing software and hardware of the HAPF, and tests are performed.The simulation and experiment result shows the validity of the methods presented in this thesis. The methods presented in this thesis have stronger robustness to the disturbances caused by variation of load, this control strategy brings the excellent performance of HAPF. The PWM inverter can exactly output the real-time compensation current; the prototype of HAPF can effectively compensates the harmonic of current and voltage in network to achieve the goal of purifying power grid.