Research On The Control Technology Of The Load-Side Converter

With the development of power electronics technology, inverter technology has been widely applied in various fields, at the same time it also puts forward more and more requirements for the output voltage waveform quality of the VVVF power supply. Therefore, researching and developing the simple also the good dynamic and static performance of the inverter control strategy, has become one of the hotspot in power electronics field. The main contents include:In the light of the difficulty of passive inverter technology, it has made a full theory analysis and simulation experiment of Matlab / Simulink on the voltage type inverter circuit and three-phase sinusoidal pulse width modulation inverter circuit, and on the basis of that it also analysises unipolar and bipolar sinusoidal pulse width modulation technique (SPWM)and its algorithm and frequency amplitude modulation, and uses the event manager module comparing unit of the DSP chip of TMS320LF2407A, outputs high precision three-phase SPWM wave, maintains its phase and waveform continuity, to better meet the passive inverter system requirements, is conducive to the stability of the system, and has a certain practical value.On the energy feedback system, it puts forward a kind of AC chopper energy feedback technology, this technology can realize the load side converter of two-way flow of energy, using AC boost-chopper, make the doubly-fed generator rotor to generate electric energy pump to high voltage DC bus, in order to make the generator stator and rotor can generate electricity at the same time ,when the doubly-fed generator running in the same the pace of time, thus improving the system work more efficient.This paper uses the motor dedicated control chip TMS320LF2407A of TI company as the control core, and constructs the load side converter experiment system, including 220V AC power, a rectification filtering, a three-phase inverter that constituted by IGBT, DC side voltage and current detecting circuit, a photoelectric isolation and driving circuit, display circuit and the keyboard and DSP control circuit. According to the characteristics of passive inverter it will feedback output signal detected by the sensor to the DSP to calculate, and according to the results of the output it is adjusted to achieve closed-loop control, and improve the operation stability of the inverter system.This paper presents the experimental results and waveform analysis, and compares the theoretical analysis and MATLAB / SIMULINK simulation waveform, essentially the same effect. Experiments show that: the load side converter experiment system can output a relatively smooth sine wave, AC boost-chopper technology can also feed energy that generated by the load back to the DC bus. The experimental results verify the validity of the system design, feasibility.