Microgrid system and a power balance control method and a small signal modeling

The present invention discloses a control strategy and a small signal modeling based on the phase compensation and selectivity virtual impedance new micro grid system and the power balance, the system comprising DG units two parallel access to AC bus, three phase resistive load and linear load, comprising a distributed power DG units connected in sequence, the inverter, the LCL-type filter circuit, the impedance of the line, two inverters and a policy control module a second policy control module; a first unit via DG a first static switch connected to AC bus, the second DG unit via a second line impedance connected to AC bus bar three-phase balanced resistive load and the linear load, respectively through the second static switch and the third static switch connected to AC bus. The present invention is proposed based on phase compensation droop control, selective virtual impedance and the secondary control novel microgrid harmonic and reactive power balance control method capable of effectively achieve harmonic and reactive microgrid in nonlinear loads power sharing.