The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for...The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.展开更多
Adjusting to Slower Pace Growth in China is expected to decelerate to 7.1 percent in 2015 and 6.9 percentby 2017,reflecting a growth trajectory that is slower but more balanced and sustainable——a＂new normal＂for th...Adjusting to Slower Pace Growth in China is expected to decelerate to 7.1 percent in 2015 and 6.9 percentby 2017,reflecting a growth trajectory that is slower but more balanced and sustainable——a＂new normal＂for the world’s second largest economy—according to the World Bank’s China Economic Update released on July 1.展开更多
基金supported by National Key R&D Program of China(No.2021YFB2401100).
文摘The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.
文摘Adjusting to Slower Pace Growth in China is expected to decelerate to 7.1 percent in 2015 and 6.9 percentby 2017,reflecting a growth trajectory that is slower but more balanced and sustainable——a＂new normal＂for the world’s second largest economy—according to the World Bank’s China Economic Update released on July 1.
