Methods and system for add-on battery
Systems and methods for operating an add-on battery that may be electrically coupled to a second system that includes an electrical energy storage device are presented. In one example, the systems and methods provide for extending operation of the second system via selectively powering the second system via the add-on battery in response to operating conditions of the second system.
1. An add-on battery system, comprising:
a battery;
a bi-directional DC/DC converter including an H-bridge comprising a transformer positioned in a horizontal circuit extending between two vertical circuits, a first of the two vertical circuits including two transistors and a second of the two vertical circuits including two additional transistors;
a controller including instructions stored in non-transitory memory to direct current flow into the battery and out of the battery via the bi-directional DC/DC converter in response to conditions of an external electrical energy storage device; and
additional instructions to activate the bi-directional DC/DC converter in response to a derivative of a voltage of the external electrical energy storage device.
2. The add-on battery system of claim 1 , further comprising:
additional instructions to activate the bi-directional DC/DC converter in response to an error between a rolling average of a voltage of the external electrical energy storage device and an instantaneous voltage of the external electrical energy storage device.
3. The add-on battery system of claim 1 , further comprising:
two operational amplifiers and an inductor, the two operational amplifiers and the inductor directly coupled to the transformer.
4. The add-on battery system of claim 3 , where the inductor is positioned in the horizontal circuit between the transformer and the two additional transistors in the second vertical circuits.
5. The add-on battery system of claim 4 , where the transformer includes two windings, where a first of the two windings is coupled to the two operational amplifiers, and where a second of the two windings is coupled to the inductor and the two transistors in the first vertical circuit.
6. The add-on battery system of claim 1 , further comprising:
additional instructions to deactivate the bi-directional DC/DC converter in response to a voltage of the external electrical energy storage device being less than a first threshold and being greater than a second threshold.
7. The add-on battery system of claim 6 , further comprising:
additional instructions to activate the bi-directional DC/DC converter in response to the voltage of the external electrical energy storage device being greater than the first threshold and being less than the second threshold.
8. An add-on battery system, comprising:
a battery;
a bi-directional DC/DC converter including an H-bridge comprising a transformer positioned in a horizontal circuit extending between two vertical circuits;
a controller including instructions stored in non-transitory memory to direct current flow into the battery and out of the battery via the bi-directional DC/DC converter in response to conditions of an external electrical energy storage device; and
additional instructions to activate the bi-directional DC/DC converter in response to a derivative of a voltage of the external electrical energy storage device.
9. The add-on battery system of claim 8 , further comprising:
additional instructions to activate the bi-directional DC/DC converter in response to an error between a rolling average of a voltage of the external electrical energy storage device and an instantaneous voltage of the external electrical energy storage device.
10. The add-on battery system of claim 8 , where the bi-directional DC/DC converter includes an H-bridge comprising a transformer positioned in a horizontal circuit extending between two vertical circuits.
11. The add-on battery system of claim 10 , where the two vertical circuits are comprised of metal oxide semiconductor field effect transistors.
12. The add-on battery system of claim 11 , where the horizontal circuit further comprises an inductor.
13. The add-on battery system of claim 8 , further comprising:
additional instructions to deactivate the bi-directional DC/DC converter in response to a voltage of the external electrical energy storage device being less than a first threshold and being greater than a second threshold.
14. The add-on battery system of claim 13 , further comprising:
additional instructions to activate the bi-directional DC/DC converter in response to the voltage of the external electrical energy storage device being greater than the first threshold and being less than the second threshold.
15. An add-on battery operating method, comprising:
supplying electrical power from a first electrical energy storage device in a first system to a second electrical energy storage device in a second system in response to electric current being supplied from the second electrical energy storage device to an external load, the second system not part of the first system, the electrical power supplied via a bi-directional DC/DC converter in the first system;
supplying the electrical power from the first electrical energy storage device to the second electrical energy storage device in response to a voltage of the second electrical energy storage device; and
activating the bi-directional DC/DC converter in response to a derivative of a voltage of the second electrical energy storage device.
16. The method of claim 15 , further comprising:
operating the bi-directional DC/DC converter in a buck mode in response to a voltage of the first electrical energy storage device being greater than a voltage of the second electrical energy storage device, where a first, a second, and a third of four transistors of an H-bridge in the bi-directional DC/DC converter operate in the buck mode and where a fourth of the four transistors in the H-bridge does not operate in the buck mode.
17. The method of claim 16 , further comprising:
operating the bi-directional DC/DC converter in a boost mode in response to the voltage of the first electrical energy storage device being less than the voltage of the second electrical energy storage device, where the second of the four transistors of the H-bridge in the bi-directional DC/DC converter does not operate in the boost mode and where the first, the third, and the fourth of the four transistors in the H-bridge operate in the boost mode.
18. The method of claim 15 , where the electrical power from the first electrical energy storage device is supplied to the second electrical energy storage device in response to the voltage of the second electrical energy storage device being less than a threshold voltage.