Control method of direct current bus voltage for voltage sag generator

The invention relates to a control method of direct current bus voltage for a voltage sag generator. The control method has the technical scheme that according to the method, a rectifying side DSP (digital signal processor) controller with a plurality of direct current bus voltage PIs (processor interfaces) is arranged at the rectifying side of a VSG (vector signal generator), an inverting side DSP controller is arranged at the inverting side of the VSG, the inverting side DSP controller receives voltage sag signals sent by the PLC and controls an inverter to generate the required alternating current voltage, meanwhile, the voltage sag signals are sent to the rectifying side DSP controller through two universal input and output openings, and the rectifying side DSP controller switches the corresponding PI controller for controlling a rectifier according to the signals, so the direct current bus voltage can maintain the stable state. The control method perfectly solves the problem that the traditional bus voltage control method cannot maintain the stable state of the direct current bus voltage during the inverting side voltage sag. The transient stability of the voltage sag generator is improved, so the safe and stable operation of the voltage sag generator is ensured.