The Control Method Research Of AC-AC Directly Frequency Converter

The frequency converter is emerging electrical equipment,which neutralizes applied electronics technology, power electronics technology, and computer control technology.Frequency control system has many merits that include energy saving, high efficiency, high degree of automation, and it is easy to operate and improve the processing quality of the products. Frequency control system has been used to various fields. AC-AC frequency converter, as an important part in power electronic technology field, has been used in various fields. For the trends of power electronic equipment developing towards high frequency,miniaturized, and the special requirement of various fields, the dynamic characteristics, the quality and the efficiency of the AC power has been concerned. AC-AC converter is an ideal frequency means,so it is getting more and more attention. Currently,AC-AC converter has been used to fields of national defense,just as aviation,aerospace,marine,and so on. The AC-AC converter is also used to the fields of civilian, just as electric power, power system,energy and transportation, oil textiles, post and telecommunications, industrial control,household appliances, and so on. In a strong proponent of green energy today, AC-AC conversion technology will play a more important role.In this paper, a new AC-AC direct frequency converter has been studied. At first, it was analyzed that the structural characteristics of the circuit topology, which is made up of twelve full-controlled switching devices and twelve diodes. The circuit topology eliminates the intermediate DC link. Then the circuit's working method was analyzed, which includes the working method of the inverter output and the energy feedback. Also the circuit's mathematical model was deduced, according to the working methods of the circuit and the characteristics of the circuit topology.Secondly a SVPWM voltage space vector PWM control method was proposed,which involves input voltage polarity detection, which meets the requirement of the output voltage adjusting to any frequency and energy feedback, after combining the traditional SVPWM voltage space vector PWM control method to the characteristics of this circuit. Then a model in Matlab/Simulink was built to analyze the output voltage and the output electric current in the present control method. Also a simulation and analysis in the range of larger output frequency was carried out.And a hardware experiment platform was built after verifying the circuit topology and the feasibility of the control method proposed in this paper. The IRF630 of the MOSFET switching devices were selected as the twelve main switching devices select. And the IR2110 and IR2117 of American International Rectifier were chosen for the switching devices driver chip. The SVPWM (voltage space vector PWM) control method was achieved with input voltage polarity detection by C language programming in CCS3.1 environment.Finally, hardware debugging experiment was carried out, which concluded that the SVPWM control method with input voltage polarity detection is feasible.