Abstract：A method for establishing edge triggered pulse control switch state time was proposed to address the

divergence of floating capacitor voltage and DC capacitor midpoint voltage in a 5-level active neutral point clamped

（ANPC-5L）inverter using the space vector pulse width（SVPWM）algorithm in the g-h coordinate system. The

fluctuation of floating capacitor voltage and the offset of DC side capacitor voltage were reduced. The principle that

the fluctuation of the floating capacitor current causes the voltage deviation of the floating capacitor was used.

Based on the principle that the same level is output under different switch states，and different switch states cause

the current direction of the floating capacitor to be opposite，within a complete cycle，the floating capacitor current cancels out each other，reducing the voltage fluctuation of the floating capacitor. An active power flow model was established to balance the midpoint voltage of the DC side capacitor by reducing the voltage fluctuation of the floating capacitor. Finally，by building a simulation platform and comparing the capacitor voltage balance of ANPC-5L before and after the application of the proposed method，the validity of the method was verified.

      Key words：active neutral point clamped（ANPC）；five level；g-h coordinate system；neutral-point balance