Photovoltaic system with energy storage and method of controlling the system

A photovoltaic system comprising

• a photovoltaic panel having an output terminal for outputting current produced by the photovoltaic panel;
• a DC-to-AC converter having an input terminal for inputting DC current and an output terminal for outputting AC current;
• a bidirectional DC-to-DC converter having a first terminal for in-/outputting DC current and a second terminal for in-/outputting DC current;
• an electrical storage;
• a control system;
• wherein:
• the output terminal of the photovoltaic panel is in electrical connection with the input terminal of the DC-to-AC converter, the DC-to-AC converter being configured for extracting power from a photovoltaic panel based on a maximum power point tracking (MPPT) algorithm;
• the first terminal of the bidirectional DC-to-DC converter is electrical connected with the photovoltaic panel and with the DC-to-AC converter, and the second terminal of the bidirectional DC-to-DC converter is electrically connected with the electrical storage, so as to provide a current drain from or a current surplus to a current flowing from the photovoltaic panel to the DC-to-AC converter by either charging or discharging the electrical storage through the bidirectional DC-to-DC converter;
• the bidirectional DC-to-DC converter is configured for controlling a current direction based on a control signal from the control system and the control system is configured to determine the power delivered by DC-to-AC converter, and configured to determine the power delivered to a load electrically connectable at the output terminal and based on the determinations, assuring that the power is delivered at the output terminal of the DC-to-AC converter by controlling the current direction through the bidirectional DC-to-DC converter to either charge or discharge the electrical storage, so that:
• if the electrical storage has a state of charge larger than a predetermined discharging setting point, and the power delivered to the load is larger than the power delivered by the DC-to-AC converter then discharge the electrical storage;
• if the electrical storage has a state of charge smaller than a predetermined charging setting point and the power delivered by the DC-to-AC converter is larger than the power delivered to the load then charge the electrical storage;
• wherein, the bidirectional DC-to-DC converter is controlled during charging and discharging of the electrical storage in manner so that voltage potential at the first terminal is set to be essentially equal to the voltage potential at the output terminal of the photovoltaic panel.