Design And Experimental Study Of The Control System Of MMC Based On TMS320F28035

Recently,the research of modular multilevel converter(multilevel converter modular,MMC)is more and more in-depth,the mainly application field including flexible DC transmission and power transmission.Due to the existence of a large number of sub modules in practical engineering applications,the MMC system needs to set up a large number of sensors,the sensor is an important part of the control device.So the MMC research work is focused on how to reduce the sensor while still ensuring the stable operation of the system.This paper has studied in measurement method of modular multilevel converter(MMC)capacitor voltage experiment.A bridge-arm needs only one voltage sensor,which measures the capacitor voltage of the bridge-arm PWM modulation unit.The capacitor voltage of non-modulation unit was obtained according to bridge current integral.In consideration of the switching loss and capacitance voltage balancing,take advantage of two switching functions.The platform based on TMS28035 shows the results which verify the validity and feasibility of the proposed control scheme.The Simulink simulation model of MMC system is built in this paper.It is proved that the method can guarantee the state estimate of the sub module to approximate the true value.The experimental platform based on TMS320F28035 controller is designed,which includes the control level system,the pulse address assignment,the sampling circuit,the driving circuit and the power sub module.The experimental results and waveforms show the feasibility and effectiveness of the proposed method.