Auxiliary power supply for energy storage systems
There is disclosed herein an energy storage system comprising an energy storage circuit, comprising a string of interconnected energy storage units configured to store electrical energy and provide power to a power grid using said stored electrical energy. The ESS further comprises an auxiliary module configured to provide auxiliary functions for at least one of the plurality of energy storage units, and an auxiliary power supply circuit for providing power to the auxiliary module from a grounded power source. The auxiliary power supply circuit is configured to galvanically isolate the energy storage circuit from the grounded power source, thereby preventing electrical arcing between the ESS, which may be at a high voltage, and ground at the grounded power source.
1. An energy storage system (ESS), comprising:
an energy storage circuit comprising a string of interconnected energy storage units configured to store electrical energy and provide power to a power grid using said stored electrical energy;
an auxiliary module configured to provide auxiliary functions for at least one of the plurality of energy storage units; and
an auxiliary power supply circuit for providing power to the auxiliary module from a grounded power source;
wherein the auxiliary power supply circuit is configured to galvanically isolate the energy storage circuit from the grounded power source,
wherein:
the auxiliary power supply circuit comprises a primary unit, a primary circuit, a secondary unit, and a secondary circuit;
the primary circuit is connected to the energy storage circuit and galvanically isolated from the grounded power source by the primary unit; and
the secondary circuit is connected to the auxiliary module and galvanically isolated from the primary circuit by the secondary unit, and
wherein:
the primary unit comprises a transmitter configured to inject a power signal into the energy storage circuit; and
the secondary unit comprises a receiver configured to receive the power signal from the energy storage circuit and convert the received power signal into power for the auxiliary module.
2. The ESS according to claim 1 , wherein: the auxiliary power supply circuit comprises at least one inductive coupling.
3. The ESS according to claim 2 , wherein: the at least one inductive coupling comprises a resonant inductive coupling.
4. The ESS according to claim 1 , wherein: the auxiliary power supply circuit comprises a plurality of primary circuits, each primary circuit being galvanically isolated from the grounded power source by a respective primary unit.
5. The ESS according to claim 4 , wherein: the auxiliary power supply circuit comprises a plurality of secondary circuits, each secondary circuit being galvanically isolated from a primary circuit by a respective secondary unit.
6. The ESS according to claim 4 , wherein:
a first auxiliary module is provided with power via a first primary circuit; and
a second auxiliary module adjacent to the first auxiliary module is provided with power via a second primary circuit.
7. The ESS according to claim 4 , wherein: the primary unit and/or the secondary unit comprise a resonant inductive coupling.
8. The ESS according to claim 1 , wherein: the power signal has a higher frequency than a characteristic frequency of the power grid.
9. The ESS according to claim 1 , wherein: the auxiliary power supply circuit is further configured to provide power from a backup power source.
10. The ESS according to claim 9 , wherein: the backup power source comprises an energy storage module from the string of energy storage modules.
11. A power grid system comprising the ESS according to claim 1 , wherein the power grid system is configured to receive and distribute electrical energy from the ESS.