System and method for supplying power from a power system
Various implementations described herein are directed to systems, apparatuses and methods for operating stand-alone power systems. The systems may include power generators (e.g., photovoltaic generators and/or wind turbines), storage devices (e.g., batteries and/or flywheels), power modules (e.g., power converters) and loads. The methods may include various methods for monitoring, determining, controlling and/or predicting system power generation, system power storage and system power consumption.
1. A method comprising:
measuring, by a controller using a sensor, a first power supplied to a load from an output terminal of a power converter, wherein a power source is connected to an input terminal of the power converter, and the load is connected to the output terminal;
determining, by the controller, a state of charge of a storage device, wherein the storage device is connected, via a switch, to the output terminal;
based on the state of charge being below a first threshold and the first power being above a second threshold and by turning the switch on, causing a first transfer of the first power, via the output terminal, to both the load and the storage device;
based on the state of charge being above the first threshold and the first power being below the second threshold and by turning the switch on, causing a second transfer of a stored power from the storage device to the load via the output terminal while disabling the power converter from transferring the first power; and
based on the state of charge being above the first threshold and the first power being above the second threshold and by turning the switch off, causing a third transfer of the first power, via the output terminal, to the load.
2. The method of claim 1 , further comprising:
measuring a second power at the input terminal of the power converter, wherein the input terminal of the power converter is connected to an output of the power source; and
sending, based on the measured second power, signals to the power converter, the signals comprising instructions for the power converter to:
shut down;
maintain a power level of the first power substantially at a power level of the second power;
reduce the power level of the first power to be below the power level of the second power; or
increase the power level of the first power to be above the power level of the second power.
3. The method of claim 1 , further comprising:
based on the state of charge being below the first threshold and the first power being below the second threshold, turning the switch off and disabling the power converter from transferring the first power.
4. The method of claim 1 , wherein the causing the first transfer, the second transfer, and the third transfer are further based on a load profile of the load.
5. The method of claim 1 , wherein the causing of the first transfer of the first power to the storage device is further based on a charge profile of the storage device, and
wherein the charge profile comprises an indication to charge the storage device by a constant voltage or by a constant current.
6. The method of claim 1 , further comprising:
controlling, based on a detection of an unsafe condition, a second switch to disconnect the power source from the power converter.
7. A method comprising:
measuring, by a controller using a sensor, a first power supplied to a load from an output terminal of a series string of power converters, wherein each power converter, of the series string of power converters, is connected to a respective power source of a plurality of power sources, and the load is connected to the output terminal;
determining, by the controller, a state of charge of a storage device, wherein the storage device is connected, via a switch, to the output terminal;
based on the state of charge being below a first threshold and the first power being above a second threshold and by turning the switch on, causing a first transfer of the first power, via the output terminal, to both the load and the storage device;
based on the state of charge being above the first threshold and the first power being below the second threshold and by turning the switch on, causing a second transfer of a stored power from the storage device to the load via the output terminal while disabling the power converters of the series string of power converters; and
based on the state of charge being above the first threshold and the first power being above the second threshold and by turning the switch off, causing a third transfer of the first power, via the output terminal, to the load.
8. The method of claim 7 , further comprising:
measuring a second power at an input terminal of one power converter of the series string of power converters; and
sending, based on the measured second power, signals to the one power converter, the signals comprising instructions for the one power converter to:
shut down;
maintain an output power level, of the one power converter, substantially at a power level of the second power;
reduce the output power level to be below the power level of the second power; or
increase the output power level to be above the power level of the second power.
9. The method of claim 7 , wherein the causing the first transfer, the second transfer, and the third transfer are further based on a load profile of the load.
10. The method of claim 7 , wherein the output terminal of the series string is connected to the load via an additional power converter.
11. The method of claim 7 , further comprising:
based on the state of charge being below the first threshold and the first power being below the second threshold, turning the switch off and disabling the power converters of the series string of power converters.
12. The method of claim 7 , wherein the causing the first transfer of the first power to the storage device is further based on a charge profile of the storage device, and
wherein the charge profile comprises an indication to charge the storage device by a constant voltage or by a constant current.
13. An apparatus comprising:
a power converter comprising:
an input terminal configured to be connected to a power source; and
an output terminal configured to be connected to a load; and
a switch configured to connect the output terminal to a storage device;
a controller configured to:
receive a measurement of a first power supplied from the output terminal to the load;
receive a measurement of a state of charge of the storage device; and
based on the state of charge being below a first threshold and the first power being above a second threshold and by turning the switch on, cause a first transfer of the first power, via the output terminal, to both the load and the storage device;
based on the state of charge being above the first threshold and the first power being below the second threshold and by turning the switch on, cause a second transfer of a stored power from the storage device to the load via the output terminal while disabling the power converter from transferring the first power; and
based on the state of charge being above the first threshold and the first power being above the second threshold and by turning the switch off, cause a third transfer of the first power, via the output terminal, to the load.
14. The apparatus of claim 13 , wherein the controller is further configured to:
receive a measurement for a second power at an input terminal of the power converter; and
send, based on the second power, signals to the power converter, the signals comprising instructions for the power converter to:
shut down;
maintain a power level of the first power substantially at a power level of the second power;
reduce the power level of the first power to be below the power level of the second power; or
increase the power level of the first power to be above the power level of the second power.
15. The apparatus of claim 13 , wherein the controller is further configured to, based on the state of charge being below the first threshold and the first power being below the second threshold, turn the switch off and disable the power converter from transferring the first power.
16. The apparatus of claim 13 , wherein the controller is further configured to cause, based on a load profile of the load, the first transfer and the second transfer of the first power to the load or the second transfer of the stored power to the load.
17. The apparatus of claim 16 , wherein the controller is further configured to periodically update the load profile of the load.
18. The apparatus of claim 13 , wherein the controller is further configured to cause, based on a charge profile of the storage device, the first transfer of the first power to the storage device, wherein the charge profile comprises an indication to charge the storage device by a constant voltage.
19. The apparatus of claim 13 , wherein the controller is further configured to cause, based on a charge profile of the storage device, the first transfer of the first power to the storage device, where the charge profile comprises an indication to charge the storage device by a constant current.
20. The apparatus of claim 13 , wherein the controller is further configured to control, based on a detection of an unsafe condition, a second switch to disconnect the power source from the power converter.