Research on power decoupling of parallel virtual synchronous machine based on feedforward control

When photovoltaic inverters operate in parallel, the output of each inverter’s impedance and the line impedance of aren’t consistent, resulting in the instantaneous voltage of each inverter at the common parallel point is not equal, so in the parallel inverters system, the circulating current is easy to form between each inverter, which affects the distribution of active power together with reactive power. In this paper, feedforward compensation is leaded-in active and reactive power control channels, and dynamic virtual complex impedance method for dynamic improvement of response performance of parallel virtual synchronous machine, so as to increase the degree of freedom of dynamic characteristic control and heighten the feedback speed. The parameters of D (damping drop coefficients) and K
f
(excitation coefficient) to make the inductive component of virtual impedance increase and counteract the resistive component, so as to the oscillation of output power is suppressed; Improving the stability of active power and reactive power and speed up the response speed of the system. The simulation display that parallel VSG in Matlab / Simulink make clear that the proposed control strategy is valid and practicable.