Photovoltaic power balancing and differential power processing
AssigneeMassachusetts Institute of Technology
InventorsArthur Hsu Chen Chang, AI-Thaddeus Avestruz, Steven B. Leeb
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Abstract
Power production among photovoltaic elements can be equalized through charge redistribution, which can reduce or eliminate the effect of partial shading. Also described is a technique for differential power processing by individually setting currents through different strings of photovoltaic elements.
Claims28
A method, comprising:
- re-distributing charge among a plurality of photovoltaic elements in a string using a photovoltaic element as switched charge storage to transfer charge between respective photovoltaic elements of the plurality of photovoltaic elements.
A circuit comprising:
- a switch network configured to re-distribute charge among a plurality of photovoltaic elements by switching a photovoltaic element in parallel with respective photovoltaic elements of the plurality of photovoltaic elements at different times.
A method, comprising:
- switching connections between photovoltaic cells in a plurality of phases, the plurality of phases including:
- a first phase comprising connecting a first group of one or more photovoltaic cells in parallel with a second group of one or more photovoltaic cells;
- and
- a second phase comprising connecting the first group of one or more photovoltaic cells in parallel with a third group of one or more photovoltaic cells.
A photovoltaic energy conversion apparatus, comprising:
- a string of photovoltaic elements comprising a first photovoltaic element and a third photovoltaic element;
- a second photovoltaic element;
- and
- a switch network comprising one or more switches, the switch network being configured to switch the one or more switches in a plurality of phases, the plurality of phases including:
- a first phase comprising connecting the second photovoltaic element in parallel with the first photovoltaic element;
- and
- a second phase comprising connecting the second photovoltaic element in parallel with the third photovoltaic element.
A photovoltaic energy conversion system comprising a plurality of strings of photovoltaic elements, the photovoltaic energy conversion system comprising:
- a controller that selects, based on an output power of the photovoltaic system, a total current to be drawn from the photovoltaic system and individual string currents to be drawn from individual strings of the plurality of strings of photovoltaic elements;
- and
- at least one current source controlled by the controller to draw the total current from the photovoltaic system and the individual string currents from the individual strings.
A photovoltaic energy conversion method for a photovoltaic energy conversion system comprising a plurality of strings of photovoltaic elements, the photovoltaic energy conversion method comprising:
- selecting, based on an output power of the photovoltaic system, a total current to be drawn from the photovoltaic system and individual string currents to be drawn from individual strings of the plurality of strings of photovoltaic elements;
- and
- drawing the total current from the photovoltaic system and the individual string currents from the individual strings.
Dependencies are inferred from the claim text.