Two-Stage Converter With Integrated Control

With the progress of power electronic device technology and the development of inverter control technology,the output voltage waveform quality of inverter and its dynamic response performance are also increasing.Under the background of the development of modern industrial energy in which various new energy is booming,the status of inverters with boosting capacity has gradually increased.However,the traditional two-stage inverter with boost capability still has a lot of room for improvement in system efficiency,and the large DC bus capacitors are the disadvantages of the volume,weight,and power density of the entire system.The bridge arm chopping the bus voltage of the higher voltage level caused a series of problems such as large harmonic content of the output voltage of the bridge arm,large volume of the output filter,and serious power loss.This article takes the characteristics of instantaneous value feedback control system to make the output waveform follow the reference modulation waveform as a starting point.Based on the thinking on how to reduce the high-frequency modulation times of each switching tube of the two-stage converter to reduce the switching loss and improve the converter efficiency The boost circuit can be boosted,and the full-bridge circuit can be equivalent to the characteristics of a buck circuit.The modulation control strategy is improved on the general boost+fullbridge two-level topology,and the integrated control strategy is used to replace the traditional control strategy.Successfully replaced the large-sized intermediate-stage bus capacitors with smaller capacitors,reducing the weight and volume of the system and increasing the power density of the system.Boost circuit output sinusoidal half-wave and full-bridge chopped waveform are synthesized into a sinusoidal AC voltage waveform.This paper uses a mathematical analysis method and combines Matlab and Simulink software to verify that compared with traditional control strategies,the harmonic content of the output voltage waveform of the bridge arm under the integrated control strategy is significantly reduced,which also reduces the post-stage filtering.The pressure of the filter can reduce the volume of the filter and further improve the power density and integration of the system.The research in this paper has positive effects in improving the efficiency of two-stage converters,reducing system volume and weight,and increasing system power density.