Developmentof Cascaded High-voltage Inverter

According to the data,the annual total electricity consumption of domestic electric motors accounts for 60% of the total electricity consumption,reaching 1.2 trillion kWh.The annual total electricity consumption of pumps and fans with a total installed capacity of more than 200 million KW accounts for 40% of the total domestic electricity consumption,reaching 800 billion kWh,of which 70% needs to be converted into frequency.However,only 5% of the fans and pumps are converted to frequency conversion as required.Assuming that the average power of the motor is 50 percent,running for 5,000 hours a year,the conversion can save 20 to 30 percent of the electricity,and 60 billion kWh a year.The variable frequency speed control system is used to modify the load of fans and pumps,which can realize automatic control of the field and optimize the operation process while saving energy.In a word,the transformation of frequency conversion can form very considerable social and economic benefits.Based on this,this paper,combined with cascaded high voltage converter,mainly states its social benefit,research direction,hot research content and topology comparison.Based on carrier phase shift control and V/F,the main circuit topology,basic principle and system composition of cascade high voltage inverter are explained in detail.Combined with the typical power circuit topology design and the selection of the entire system parameters,a scheme including ventilation cooling,thermal simulation,prototype structure and electromagnetic compatibility is formed.Full digital signal processing control cabinet,that is,based on the 6U standard cabinet,the installation of various functional modules,such as optical pass sub-board,sampling template,IO module and main control board,is completed by means of plug-in card installation.Install the power module control panel in the power module and use it as the control terminal.The whole design process always adheres to the basic principles of scalability,reliability and system integrity.Combined with the following three aspects,this paper comprehensively discusses the method to realize the function of the control system.The second is the control interface.Finally,circuit design.At the end of the paper,a cascade high voltage converter prototype is tested.The test results show that all the performances meet the relevant requirements and standards.