Photovoltaic power generation virtual inertia compensation system and method based on super capacitor energy storage

A photovoltaic power generation virtual inertia compensation system based on SCES, comprising a photovoltaic array, a unidirectional DC-DC boost circuit and a grid-connected inverter, which are electrically connected in sequence, the grid-connected inverter outputting alternating current to the power grid,

• wherein the virtual inertia compensation system further comprises a supercapacitor assembly for energy storage, a bidirectional DC-DC converter and a virtual inertia control module;
• a port on a side of the bidirectional DC-DC converter is electrically connected to an output end of the unidirectional DC-DC boost circuit and an input end of the power grid inverter, and a port on the other side thereof is electrically connected to the supercapacitor assembly;
• the bidirectional DC-DC converter comprises two power switch devices;
• the virtual inertia control module comprises a first inverting adder, a virtual inertia converter, a second inverting adder, a first PI controller, a third inverting adder, a second PI controller and a PWM modem, which are electrically connected in sequence;
• wherein instantaneous frequency and nominal frequency of the power grid are each input to positive and negative input ends of the first inverting adder;
• a difference between the instantaneous frequency of the power grid and the nominal frequency of the power grid is input to the virtual inertia converter, and the virtual inertia converter outputs a nominal voltage of the supercapacitor assembly;
• an input end of the positive and negative input ends of the second inverting adder is electrically connected to an output end of a nominal voltage calculator of the supercapacitor assembly, and the instantaneous voltage of the supercapacitor assembly is input to the other input end of the second inverting adder;
• an input end of the positive and negative input ends of the third inverting adder is electrically connected to an output end of the first PI controller, and an instantaneous current of the supercapacitor assembly is input to the other input end of the third inverting adder;
• and
• the PWM modem outputs pulse signals to control the on/off of the power switch devices of the bidirectional DC-DC converter.