String current limited battery charging control
View Patent ↗Systems and methods for charging a plurality of battery strings are provided. The individual string current of each of the individual battery strings can be monitored and used to regulate a charging output provided by the charger. For instance, the output voltage of charger can be controlled as part of a closed loop control system based on the individual string current of the battery string under the constraint of an individual string current limit and/or a charging voltage limit. As the charging voltage of the charger increases as a result of the closed loop control based on the individual string current, other battery strings can be coupled to the charger when the charging voltage provided by the charger exceeds a battery string voltage associated with the battery string.
1. A battery system, comprising:
one or more control devices configured to control a charging output of a charger based at least in part on a string current of at least one of a plurality of battery strings, wherein the charging output is set to a minimum string voltage and increases based on feedback from the plurality of battery strings;
wherein the one or more control devices is configured to control a plurality of battery string contactors, each battery string contactor associated with at least one of the plurality of battery strings, to sequentially couple each of the plurality of battery strings to the charger when a charging voltage of the charger exceeds a battery string voltage associated with the battery string; and
wherein the one or more control devices is configured to sequentially couple the plurality of battery strings to the charger in ascending order of battery string voltage.
2. The battery system of claim 1 , wherein the one or more control devices are configured to control the charging output of the charger based at least in part on a string current limit.
3. The system of claim 1 , wherein the charging output comprises the charging voltage output by the charger.
4. The system of claim 3 , wherein the one or more control devices are configured to control the charging output of the charger based at least in part on a charging voltage limit.
5. The system of claim 1 , wherein the charging output comprises a charging current output by the charger.
6. The battery system of claim 1 , wherein the one or more control devices are configured to open the plurality of battery string contactors prior to charging the plurality of battery strings.
7. The battery system of claim 1 , wherein the one or more control devices are configured to first couple the battery string having a lowest battery string voltage to the charger.
8. A method for connecting a plurality of battery strings to a charger, each battery string including two or more batteries or battery cells connected in series or parallel configuration, the method comprising:
coupling a first battery string of a plurality of battery strings to a charger;
monitoring a string current for the first battery string;
controlling, by one or more control devices, a charging voltage provided by the charger based at least in part on the string current for the first battery string, wherein the charging voltage is set to a minimum string voltage and increases based on feedback from the plurality of battery strings;
coupling a second battery string to the charger when the charging voltage is greater than a voltage of the first battery string; and
sequentially coupling additional battery strings to the charger when the charging voltage exceeds the battery string voltage associated with the previously coupled battery strings.
9. The method of claim 8 , wherein coupling the second battery string to the charger comprises closing a contactor coupled in series with the second battery string.
10. The method of claim 8 , wherein the charging voltage is controlled based at least in part on a charging voltage limit.
11. The method of claim 8 , wherein the charging voltage is controlled based at least in part on a string current limit.
12. The method of claim 8 , wherein the first battery string has a lowest battery string voltage of the plurality of battery strings.