Secondary control method and apparatus of parallel inverters in micro grid

A secondary control apparatus of parallel inverters in micro grid, comprising:

• a fundamental voltage instruction value generation module, for generating a frequency instruction value and an amplitude instruction value of the fundamental voltage in the voltage instructions of the inverter by using a droop control according to an output voltage and an output current of the inverter, so as to obtain a fundamental voltage instruction value Vfund;
• an AC signal voltage instruction value generation module, for extracting current values of a first AC signal and a second AC signal from the output current of the inverter, extracting voltage values of the first AC signal and the second AC signal from at least one voltage signal, generating a frequency instruction value of the first AC signal by using the droop control so as to obtain a voltage instruction value of the first AC signal, and generating a frequency instruction value of the second AC signal by using the droop control so as to obtain a voltage instruction value of the second AC signal;
• and
• a regulation module, for regulating the output voltage of the inverter according to the voltage instruction value of the first AC signal, the voltage instruction value of the second AC signal, and the fundamental voltage instruction value Vfund.