The Research On The Asymmetric Sinusoidal Inverter

To meet the need of the research of Micro-plasma oxidation, the process researchers need an asymmetric sinusoidal inverter whose amplitudes between the positive period and the negative are different, and its amplitude and frequency can be regulated continuously in some range. On the base of this application background, a small power asymmetric sinusoidal inverter is studied in this subject. It will offer some help in theoretical analysis and practical technical design for researching the large power experimental inverter.In this paper, the feasibility of SPWM modulated technique applied into asymmetric sinusoidal wave is analyzed theoretically firstly. And several principles for the design of the corresponding filter link are given. The full-bridge topology and HPWM control method are adopted in this inverter. And the filter link is composed of a LC low-pass filter and a LC resonance filter. UC3825 is selected as the control chip for the control circuit and the corresponding function block circuits are designed for it. From it, four driver control signals the main circuit needed is acquired. Then on the base of the open loop experiments of the inverter, the reasons that causing the distort at the zero-crossing of the output voltage waveform are analyzed.The design of the close loop is one focal point in inverter design. In this project, the principles of operation of the voltage feedback single-loop control and the inductor current feedback double-loops control method are discussed respectively. And the design principles of their regulators'parameters and load adaptabilities are discussed respectively too.In order to guarantee the exactness of the design philosophy, the design method composed of simulation and experiments is adopted for designing the inverter. And on this base, a small power experimental inverter has been designed and debugged. The experimental results indicate that this inverter meet all design targets well.