Enhanced systems and methods for using a power converter for balancing modules in single-string and multi-string configurations
View Patent ↗Apparatuses and methods include a solar array having one or more string buses of series-connected solar modules. The current outputs from the solar modules on each string bus can be balanced along with the voltage output from the string buses. Local management units coupled between the solar modules and the string buses are configured to control the voltage output from each solar module. When the solar modules on each string are balanced, and when the string buses are balanced (or before the solar modules and string buses are balanced), an inverter or other device connected to the solar array can find the array's maximum power point via a maximum power point tracking algorithm.
1. A solar array comprising:
a plurality of string buses connected in parallel in the solar array;
a plurality of solar modules, wherein
each respective solar module of the solar modules has a local management unit configured to provide, to one of the string buses, electrical power generated by the respective solar module, and
each respective string bus of the string buses connects in series electrical power provided by local management units of a subset of the solar modules in the respective string bus;
a controller configured to communicate with local management units of the solar modules to:
adjust current-voltage output characteristics of at least one solar module in the respective string bus to cause the at least one solar module to have a maximum module current output that matches with maximum module current outputs of the other solar modules in the respective string bus; and
adjust current-voltage output characteristics of at least one string bus to cause the at least one string bus to have a maximum string voltage output that matches with maximum string voltage outputs of the other string buses connected in parallel in the solar array; and
a maximum power point tracker coupled with the string buses to receive electrical power from the string buses in parallel, the maximum power point tracker configured to track a maximum power point of the plurality of string buses by varying a current passing through the maximum power point tracker at a time when the solar modules in the respective string bus are configured via the local management units to have the maximum module current output in current-voltage output characteristics and the string buses in the solar array are configured via the local management units to have the maximum string voltage output in current-voltage output characteristics.
2. The solar array of claim 1 , wherein the controller is part of one of the local management units of the solar modules.
3. The solar array of claim 1 , wherein an operation of the controller is based on historical current and voltage data.
4. The solar array of claim 1 , wherein the respective solar module of the solar modules provides, via the local management unit, the electrical power generated by the respective solar module solely to the respective string bus.
5. A method of operating a plurality of solar modules, the method comprising:
communicating, by a controller, with local management units of the plurality of solar modules in a plurality of string buses, the string buses connected in parallel in a solar array, wherein
each respective solar module of the solar modules has a local management unit configured to provide, to one of the plurality of string buses, electrical power generated by the respective solar module,
each respective string bus of the string buses connects in series electrical power provided by local management units of a subset of the solar modules in the respective string bus, and
a maximum power point tracker is coupled with the string buses to receive electrical power from the plurality of string buses in parallel, the maximum power point tracker configured to track a maximum power point of the plurality of string buses;
wherein the communicating includes:
communicating with the local management units of the solar modules to adjust current-voltage output characteristics of at least one solar module in the respective string bus to cause the at least one solar module to have a maximum module current output that matches with maximum module current outputs of the other solar modules in the respective string bus; and
communicating with the local management units of the solar modules to adjust current-voltage output characteristics of at least one string bus to cause the at least one string bus to have a maximum string voltage output that matches with maximum string voltage outputs of the other string buses connected in parallel in the solar array;
wherein the maximum power point tracker tracks the maximum power point of the plurality of string buses by varying a current passing through the maximum power point tracker at a time when the solar modules in the respective string bus are configured via the local management units to have the maximum module current output in current-voltage output characteristics and the string buses in the solar array are configured via the local management units to have the maximum string voltage output in current-voltage output characteristics.
6. The method of claim 5 , further comprising applying by the maximum power point tracker, a maximum power point tracking algorithm to the plurality of string buses as a whole.
7. The method of claim 5 , wherein the respective solar module of the solar modules provides, via the local management unit, the electrical power generated by the respective solar module solely to the respective string bus.
8. A method of operating a plurality of solar modules, the method comprising:
communicating, by a controller, with local management units of the plurality of solar modules connected in a string bus, wherein
each respective solar module of the solar modules has a local management unit configured to provide electrical power generated by the respective solar module to the string bus,
the string bus connects in series electrical power provided by local management units in the string bus, and
a maximum power point tracker is coupled with the string bus to receive electrical power from the string bus, the maximum power point tracker configured to track a maximum power point of a solar array including the string bus;
wherein the communicating includes:
communicating with the local management units of the solar modules to adjust current-voltage output characteristics of at least one of the solar modules in the string bus to cause the at least one solar module to have a maximum module current output that matches with maximum module current outputs of the other solar modules connected in the string bus;
wherein the maximum power point tracker tracks the maximum power point of a solar array including the string bus by varying a current passing through the maximum power point tracker at a time when the solar modules in the string bus are configured via the local management units to have the maximum module current output in current-voltage output characteristics.
9. The method of claim 8 , wherein the respective solar module of the solar modules provide via the local management unit, the electrical power generated by the respective solar module solely to the string bus.
10. A solar array comprising:
a plurality of solar modules, each of the solar modules having a local management unit;
a string bus configured to receive electrical power generated by the solar modules via series-connected local management units of the solar modules; and
a controller configured to communicate with the local management units of the solar modules to balance currents produced by the solar modules via adjusting current-voltage output characteristics of at least one of the solar modules in the string bus to have a matching maximum module current output with the other solar modules connected in the string bus;
wherein each of the solar modules provides electrical energy only to the string bus via a corresponding one of the series-connected local management units.
11. The solar array of claim 10 , wherein the local management units control voltage outputs from the solar modules.
12. A solar array system having a plurality of solar modules, the system comprising:
a plurality of string buses, each respective string bus of the plurality of string buses configured to receive electrical power from at least one solar module, wherein each respective solar module of the plurality of solar modules includes a local management unit configured to provide electrical power generated by the respective solar module to the respective string bus;
a maximum power point tracker coupled with the plurality of string buses to receive electrical power from the string buses in parallel; and
a controller configured to communicate with local management units of the solar modules to adjust current-voltage output characteristics of at least one of the string buses to have a matching maximum string voltage output with the other string buses in the plurality of string buses.
13. The solar array system of claim 12 , wherein the respective solar module of the plurality of solar modules provides, via the local management unit, the electrical power generated by the respective solar module solely to the respective string bus.