CPC H02J 9/062 (2013.01) [H02J 3/01 (2013.01); H02J 3/18 (2013.01); H02J 3/32 (2013.01)] | 20 Claims |
1. A power supply system, comprising:
an uninterruptible power supply (UPS) comprising:
an input terminal configured to:
couple to a power grid using a first node, and
receive an alternating current from the power grid;
an output terminal configured to couple to a load using a second node;
a bypass switch circuit comprising:
a first terminal coupled to the input terminal; and
a second terminal coupled to the output terminal, wherein the bypass switch circuit is configured to connect the power grid to the load;
a direct current to alternating current (DC-AC) conversion circuit, wherein the DC-AC conversion circuit is connected to the output terminal, and wherein the DC-AC conversion circuit is configured to:
receive a first control instruction; and
output a current to the output terminal in response to the first control instruction;
a collection point node disposed between the first node and the second node;
a collection circuit connected to the collection point node, wherein the collection circuit is configured to:
receive a second control instruction; and
collect a current at the collection point node in response to the second control instruction; and
a control circuit configured to:
send the first control instruction to the DC-AC conversion circuit;
send the second control instruction to the collection circuit;
control, in a collection period in a first duration, the collection circuit to collect a first current at the collection point node;
determine at least one of a harmonic component or a reactive current component of the first current;
control, in a current equalization period in the first duration, the DC-AC conversion circuit to output a first compensation current, wherein the current equalization period partially overlaps the collection period, wherein the first compensation current comprises at least one of a first compensation reactive current component or a first quantity of first compensation harmonic components, wherein the first quantity is less than or equal to a second quantity of harmonic components of the first current, wherein the first compensation reactive current component in the first quantity of first compensation harmonic components has a same frequency and an opposite amplitude as the harmonic component of the first current, and wherein the first compensation reactive current component has a same frequency and an opposite amplitude as the reactive current component; and
adjust a second duration in which the bypass switch circuit connects the power grid to the load to balance second currents output by output terminals of different UPSs in a plurality of UPSs or balance third currents output by bypass switch circuits of the different UPSs.
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