Patent ID: 11936310
Assignee: DELTA ELECTRONICS (SHANGHAI) CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. The control method of the three-phase AC system according to claim 1, wherein when the three-phase AC system operates in an off-grid mode, a harmonic voltage in the output voltage of the three-phase AC system is controlled, and the step 3 comprises:
performing coordinate transformation on the output voltage of the three-phase AC system to obtain a voltage signal, performing low-pass filtering on the voltage signal to obtain a fundamental voltage, and subtracting the fundamental voltage from the voltage signal to obtain the harmonic voltage; and
performing the coordinate transformation of multiple coordinate systems on the harmonic voltage to obtain the harmonic voltages corresponding to the multiple coordinate systems, and setting a reference value of the harmonic voltage in each of the coordinate systems to zero to obtain the error signal in each of the coordinate systems.