NLM modulation MMC harmonic analysis method based on equal interval trigger control

• Main Authors: CHEN XIAOWEN, ZHANG YE, JIAO ZAIBIN, YUAN HAO, LI JIANHUA, ZHAO YONG, TU LIANG, HONG CHAO
• Format: Patent
• Language: Chinese; English
• Published: 17.07.2020
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CALCULATING; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; COMPUTING; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; GENERATION; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; SYSTEMS FOR STORING ELECTRIC ENERGY; TESTING

The invention discloses an NLM modulation MMC harmonic analysis method based on equal interval trigger control. The method comprises the steps of adopting a time domain analysis method, establishing aharmonic model of the MMC from the characteristics of a nearest level approximation modulation technology, decomposing step waves into the superposition of a series of rectangular waves, then utilizing the Fourier series expansion, and finally obtaining a universal differential mode phase voltage harmonic analysis expression for triggering and controlling the MMC at equal intervals. According tothe invention, only according to the five input data of a direct current side bus voltage Vdc, a carrier ratio F, a modulation ratio m, the number N of sub-modules contained in each phase of upper/lower bridge arm and an electrical angle theta 1 corresponding to the equal interval trigger control starting moment in one fundamental wave period, the content of each harmonic of the differential modephase voltage of the neares