Research On The Technology Of Low Frechency Inverter Based On DSP

Power electronics technology is more than one of the subjects of mutual infiltration integrated technical disciplines which is widely used in electricity, transportation, communications and other field as well. Inverter technology is the research focus of power electronics technology. At present, studies mainly concentrate on the 50 Hz frequency band, as well as several kilohertz high frequency band, but few on low-frequency inverter technology. Based on the application background of doubly-fed wind turbine generator control system, this thesis studies a number of issues on the low-frequency inverter technology, including:Aimed at solving the problems of low-frequency inverter technology, sufficient theoretical analysis and simulation are carried out to inverter technology by using three-phase full bridge converter and on that basis a organic combination of the traditional asynchronous and synchronous modulation technique of modulation technology is taken. A study on ultra-low-frequency inverter is applied to the modulation - subsection synchronous modulation, which effectively solved the process of ultra-low frequency inverter harmonics generated by the instability of the output waveform, and other issues.Based on this study, an AC boost-chopper energy feedback technology can be doubly-fed generator rotor of the low voltage electrical energy to pump the way Chopper exchange rose HVDC bus, so as to achieve energy converter in the two-way mobile, making doubly-fed generator running on the super-synchronous speed, the generator stator and the rotor can simultaneously power generation, thereby improving the system's efficiency.This thesis constructed experimental low-frequency inverter system, by using TI's TMS320LF2407 motor control chip as the exclusive control of the core, including inverter and the driving circuit, load detection circuit parameters, system protection circuit. According to the characteristics of ultra-low frequency inverter will be detected by the sensor signal back to the DSP calculated on the basis of the calculation results to adjust output to achieve closed-loop control and improve the stability of inverter system operation.Papers presented experimental results and waveform analysis, and theoretical analysis and MATLAB / Simulink simulation waveform comparisons basically the same effect. Through experiments, it proves that: 0.6 Hz - 10Hz range from the experimental low-frequency inverter system more smooth sine wave output, the exchange Chopper rotor technology can also produce the energy feedback to the DC bus of work..Experimental results demonstrate the effectiveness of the system design, and feasibility.