Research On Control Method Of Medium Frequency Sinusoidal Inverter Based On DSP

This paper studies the control method of inverter, and focuses on the medium frequency inverter witch the frequency of output voltage is 400Hz. Many experts from home and abroad have proposed some control technology to achieve an output voltage with low THD, high stability and fast transient response. Multiple-loop feedback control and repetitive control are more popular.This paper presents a theoretical analysis and simulation results on the multiple-loop feedback control scheme and repetitive control scheme. Multiple-loop feedback control approach has a good dynamic performance and it is easy to implement and design. However, it can not thoroughly eliminate the steady-state error. While repetitive control strategy has a merit in dealing with steady-state error, but it is transient response is very poor. The multiple control technology based on two loop feedback control and repetitive control is proposed. Two loop feedback controller, which can improve the dynamic performance of the system serves as an inner-layer controller. Therefore, the design of the outer-layer repetitive controller is simplified. Thus, the two control strategies can coordinate with each other so that the Medium Frequency inverter can produce high quality voltage waveform and has a fast transient response.Control circuit of inverter is designed by TMS320F240 DSP, the software of DSP is designed by assembler based on multiple control technology. The correctness of theoretical analysis and simulation are proved by experiment, the control system of medium frequency inverter used multiple control method is achieved by DSP.