Bridge arm instantaneous current direct control method of modular multilevel converter

The invention relates to a bridge arm instantaneous current direct control method of a modular multilevel converter and belongs to the field of a power electronic equipment control technology. The method comprises the following steps: data required by control is acquired and obtained; a bridge arm current reference value is calculated by the use of each obtained current reference value; a bridge arm induction voltage reference value is calculated by the use of a bridge arm inductance value, a control cycle, the calculated bridge arm current reference value and a measured bridge arm current value; a bridge arm output voltage reference value is calculated by the use of an obtained AC port voltage reference value, a DC port voltage reference value and the obtained bridge arm induction voltage reference value; each bridge arm modulation reference wave is calculated by the use of the calculated bridge arm output voltage reference value and measured bridge arm total capacitor voltage; and the generated modulation reference wave is sent to a valve trigger pulse modulator so as to directly control bridge arm instantaneous current. The method has fast control response speed and is not influenced by the transient process. By the method, it is guaranteed that bridge arm overcurrent will not happen to a converter and capacitor overvoltage also will not happen.