Power generation frequency control

A solar power generation system comprising:

• (a) a DC to AC converter for receiving power from a photovoltaic (PV) module and supplying power to a power network, wherein the DC to AC converter is coupled to the power network along a power line;
• (b)an energy storage unit coupled to the power line through an additional power converter for supplying or absorbing energy when needed to support frequency stabilization of the power network;
• (c) a control system comprising
• (i) a power point tracker to extract either (a) maximum power available from the PV module or (b) less than maximum power available from the PV module;
• (ii) a frequency monitor to obtain a network frequency from the power network;
• (iii) an internal reference frame element to provide an internal reference frequency of the solar power generation system;
• (iv) a frequency comparator to compare the network frequency and the internal reference frequency;
• and
• (v) a command signal generator to provide a command signal to adjust the commanded output power, the supply or absorption of energy by the energy storage unit, or both when the network frequency differs from the internal reference frequency by a comparison limit.

A method of operating a solar power generation system comprising, a photovoltaic (PV) module, a DC to AC converter coupled to the PV module and for supplying power to a power network, the method comprising

• using a power point tracker element to extract either maximum power available from the PV module or less than maximum power available from the PV module;
• obtaining a network frequency from the power network;
• providing an internal reference frequency of the solar power generation system;
• comparing the network frequency and the internal reference frequency;
• and
• using the frequency comparison to determine whether a transient increase or decrease in commanded output power is warranted and to provide a command signal.