The Research On Digital Control Of Three-Phase Power Factor Correction Technology

With the rapid development of the power electronics technology, conventional rectifier equipment and AC motors the electrical equipment that is nonlinear are greatly applied into the gird. The electrical equipment that is nonlinear makes the grid voltage and current phase not synchronized, and makes a large number of harmonic interference into the gird, thus pollutes the gird. Today, the energy is shortage, improving the power factor of Electrical equipment, reducing the reactive loss make a positive impact on building the saving society. At present, the research of single-phase PFC Technology has been maturing, this topic focuses on the digital control system realize of three-phase PFC, it mainly uses the Methods of Theoretical modeling and simulation and designing the prototype to compare the testing and theoretical value.In this article, firstly, the principle, method and meaning of Power factor correction are discussed in detail. On this basis, it analyzes the main circuit and the current flow patterns of the type of three-phase six switching boost PFC, then it establishes the Mathematical model Based on the switching function, thus realizes the conversion in different coordinate systems. Secondly, it analyzes the Digital control system strategy and completes the feed-forward decoupling of system parameter variables, then designs a double-loop PI controller. Meanwhile, the modulation algorithm on SVPWM has been improved, and the PWM modulation sequence in different sectors of Space vector based on the algorithm is given. In the simulation software of SABER, the mathematical modeling of three-phase PFC main circuit and the control system of each sub-module are discussed, and it makes a simulation of each module with the simulated load, and verifies the theoretical analysis of the system.Finally, based on theoretical analysis, it designs an AC/DC prototype with the function of power factor correction. In the prototype, the master unit is the TMS320F2812, the input is220V three-phase AC, the output is600V DC, the capacity is lOkVA.Then it calculates and selects the critical device parameters of the main circuit, and gives the main hardware circuits and software algorithm. On this basis, it makes a load test on the prototype, thus further verifies the correction of the system designing in theory.