Modular multilevel converter driving signal modulation method and fault isolation method

摘要

A modular multilevel converter driving signal modulation method and a sub-module unit fault isolation method. The modular multilevel converter driving signal modulation method comprises a first mode and a second mode, the first mode and the second mode operating in a cyclical manner. In the first mode, a first power semiconductor switch (T1) and a second power semiconductor switch (T2) are turned on in an alternating manner, and at the same time, a third power semiconductor switch (T3) is turned off in a normal manner and a fourth power semiconductor switch (T4) is turned on in a normal manner. In the second mode, the third power semiconductor switch (T3) and the fourth power semiconductor switch (T4) are turned on in an alternating manner, and at the same time, the first power semiconductor switch (T1) is turned on in a normal manner and the second power semiconductor switch (T2) is turned off in a normal manner. The junction temperatures of the power semiconductor switches are balanced, increasing the operational safety margin of a converter. The capacity of a converter may be effectively increased without increasing engineering costs, and performance is better in both economic and technical terms.