Study On The High-Frequency-Link Inverter Based On DSP

Nowadays, high power density and high efficiency have always been the goal to pursue in the field of modern electric power converters. High-Frequency Link technology is the basic technology for the light and minitype development of the inverter.This paper focuses on a High-Frequency Link Inverter with Full-Bridge Inverter-cycloconverter as its main circuit topology and DSP as its core controller. The fundamental principles of the sinusoidal pulse width phase modulation control strategy and the control method is described in detail. The paper elaborates the hardware design and illustrates the main software algorithm for the inverter.The paper introduces the research work that has been done home and abroad on the High-Frequency Link inverter and the prospect of application. Based on the Compare with the representative topology, the main scheme of the inverter discussed in the paper is DC(low voltage)/AC(low voltage high frequency SPWPM pulse)/AC(high voltage and low frequency sine wave). the scheme enables the inverter to have only two levels of power conversion and offers a simple structure and few harmonious waves in the output.In the control circuit unit, The TMS320LF2407 is used as the main control unit. the SPWPM(sinusoidal pulse width phase modulation) control strategy and the output of the SPWPM wave generated by its compare unit is discussed. The drive signal of the MOSFET in the cycloconverter is the logic circuit combination of the output voltage signal, the output current signal and the rectangular wave with the same frequency as the carrier wave. It make the cycloconverter can work at the low or high frequency according to the load character.To achieve a good performance both statically and dynamically, closed loop control method has to be applied. The paper uses close-loop control method based on instantaneous voltage feedback, and enables the inverter to produce steady sinusoidal waves by the digital PID adjuster designed. The protection circuit is also mentioned.In the end, the emulation results of the High-Frequency Link Inverter are also presented and discussed in the paper.