The potential multiple oscillation modes existing in a photovoltaic (PV) microgrid are seldom

if ever

studied in previous references. A full-order small signal model is developed for a typical microgrid containing a PV micro-source. Three dominant oscillation modes are discovered through eigenvalue analysis

namely

5 Hz to 20 Hz oscillation

60 Hz oscillation

and 800 Hz to 1 000 Hz oscillation

respectively. The sensitivities of eigenvalues of the state variables are analyzed through participation factors

and the origin of each oscillation mode is revealed. The influences of the variation of the controller and network parameters on system small signal stability are analyzed through the model developed. Through disturbance tests in an experimental laboratory microgrid

the three oscillation modes are exactly observed

verifying the correctness of the established full-order small signal. This model can help optimize the parameters of both the main circuit and the controller of a PV micro-source.