The Research On Active Power Filter Based On TMS320F2812

As the techniques of power electronics have been made great strides,electronics and electric devices are widely used, which do bring about convenience, efficiency and enormous profits. However, with characteristics of non-linearity, impulsion and electric imbalance, these devices produce abundance of harmonic and reactive power in the power grid, which causes so distinct decline of power quality that the security and normal operation of power grid and electrical equipment might be endangered. This research aims at designing a device which can eliminate the harmonic in three-phase three-wire power grid.At first, three main kinds of filter (high power factor converter, passive filter and active power filter) are set forth, and their advantages, shortcomings and hot spots of research nowadays are introduced. Content and target of the study is summed up according to the principle of shunt active power filter.Secondly, critical technology of active power filter, including real time detection technology of harmonic and control technology of converter, is recommended. By analyzing their advantages and shortcomings, instantaneous reactive power theory is adopted to achieve real time detection of harmonic, space vector pulse width modulation with two hysterics is adopted to control converter, detailed introduction on both are offered thereafter.Thirdly, the option method of every component is presented after analyzing the mathematical model of active power filter, capacitance and its voltage value, inductance value, request of switching device, low-pass filter and its cutoff frequency, control strategy of DC voltage is fixed. Simulation model, based on MATLAB/SIMULINK, is established, and run under given parameter and condition. Simulation results show that each simulated model can perform its function and the overall system can fulfill filtered assignments..Then on the basis of correct simulation, hardware is designed according to the concept of modulization, which include signal detection model, control model, protection model, converter and its drive model. Debugging results show that analog signals can be accurately converted to digital signals which can be accepted by DSP via detection model; control model can output the correct waveform according to program; converter and its drive model can work normally; protection model reflect the fault and act correctly. Hence, the overall hardware is proper designed, and can run safely and reliably.Finally, the C program applied to TMS320F2812 is debugged based on hardware. The program contains initialization program, capture program, main program (A/D sampling program, harmonic algorithm program, PI program of capacitor voltage), PWM signal program and troubleshooting program. Since the software and hardware debug have been successfully completed, accurate detection of harmonic is realized, which makes a solid foundation for the experiments of main circuit.