The invention discloses a
microgrid control method having functions of
voltage unbalance compensation and
harmonic suppression. An
integrated controller acquires a common
bus voltage and calculates an unbalance factor vector, a characteristic order
harmonic component positive-sequence compensation
reference vector and a characteristic order
harmonic component negative-sequence compensation
reference vector of the common
bus voltage, and transmits the vectors to a local controller of every parallel
inverter through low-bandwidth communication. In the local controller, a characteristic order harmonic positive- and negative-sequence compensation
voltage vector is calculated and is superposed with a reference
voltage vector, a
virtual impedance voltage vector and the common
bus voltage unbalance factor vector to synthesize and correct a voltage regulating
reference vector, and unbalance compensation and harmonic suppression of the common
bus voltage is carried out through
inverter voltage and current control. By applying the method provided by the invention to a multi-
inverter parallel
system in which a common bus is connected with a three-phase unbalanced load and a nonlinear load, three-phase voltage balance of the
microgrid can be maintained, output
voltage distortion of three-phase inverters can be reduced, and output power of the parallel inverters can be accurately allocated.