Phase angle measurement and pre-synchronization method and device of PWM inverter and computer equipment

The invention relates to the technical field of PWM (Pulse Width Modulation) inverters, and discloses a phase angle measurement and pre-synchronization method and device for a PWM inverter, and computer equipment, which are used for measuring at the beginning and the end of a zero vector and calculating current increase so as to calculate voltage drop on an inductor. The sequence is repeated in the following two sampling periods, and the voltage difference can be calculated; the current on the capacitor can be calculated through the voltage difference of the capacitor at the two preset moments. Finally, the grid voltage and angle may be determined taking into account the estimated capacitor current and inductor voltage. And then, grid connection is carried out through the estimated initial value of the grid-side voltage angle. After grid connection, the zero-voltage vector pulse is closed, the grid-side voltage is continuously estimated through the current flowing through the inductor, the phase angle informa