Power conditioning units
First Claim
1. A power conditioning unit with photovoltaic maximum power point tracking (MPPT), for delivering power from a photovoltaic dc power source to an ac mains power supply, the power conditioning unit comprising:
- an input for receiving power from said photovoltaic dc power source;
an output for delivering ac power to said ac mains power supply;
an energy storage capacitor for storing energy from said photovoltaic dc power source for delivering to said ac mains power supply output;
a dc-to-ac converter coupled to said output for converting energy stored in said energy storage capacitor to ac power for said ac mains power supply output; and
a power injection control block having a sense input coupled to said energy storage capacitor and having an output coupled to said dc-to-ac converter, to control said dc-to-ac converter to control power injected into said ac mains power supply;
wherein said power injection control block is configured to track a maximum power point of said dc power source without measuring a dc voltage or dc current provided from said photovoltaic dc power source.
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Accused Products
Abstract
We describe a power conditioning unit with maximum power point tracking (MPPT) for a dc power source, in particular a photovoltaic panel. A power injection control block has a sense input coupled to an energy storage capacitor on a dc link and controls a dc-to-ac converter to control the injected mains power. The power injection control block tracks the maximum power point by measuring a signal on the dc link which depends on the power drawn from the dc power source, and thus there is no need to measure the dc voltage and current from the dc source. In embodiments the signal is a ripple voltage level and the power injection control block controls an amplitude of an ac current output such that an amount of power transferred to the grid mains is dependent on an amplitude of a sinusoidal voltage component on the energy storage capacitor.
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Citations
20 Claims
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1. A power conditioning unit with photovoltaic maximum power point tracking (MPPT), for delivering power from a photovoltaic dc power source to an ac mains power supply, the power conditioning unit comprising:
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an input for receiving power from said photovoltaic dc power source; an output for delivering ac power to said ac mains power supply; an energy storage capacitor for storing energy from said photovoltaic dc power source for delivering to said ac mains power supply output; a dc-to-ac converter coupled to said output for converting energy stored in said energy storage capacitor to ac power for said ac mains power supply output; and a power injection control block having a sense input coupled to said energy storage capacitor and having an output coupled to said dc-to-ac converter, to control said dc-to-ac converter to control power injected into said ac mains power supply; wherein said power injection control block is configured to track a maximum power point of said dc power source without measuring a dc voltage or dc current provided from said photovoltaic dc power source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of photovoltaic maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a photovoltaic dc power source to an ac mains power supply, the power conditioning unit including an energy storage capacitor for storing energy from said photovoltaic dc power source for delivering to an ac mains power supply output, the method comprising:
tracking a maximum power point of said photovoltaic dc power source by controlling a dc-to-ac converter converting energy stored in said energy storage capacitor to ac power for said ac mains power supply output, wherein said tracking is performed without measuring a dc voltage or dc current provided from said photovoltaic dc power source. - View Dependent Claims (14, 15, 16)
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17. A method of photovoltaic maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a photovoltaic dc power source to an ac mains power supply, the power conditioning unit including an energy storage capacitor for storing energy from said photovoltaic dc power source for delivering to an ac mains power supply output, wherein, in operation, a voltage on said energy storage capacitor has a sinusoidal voltage component at twice a frequency of said ac mains power supply, the method comprising:
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controlling an amplitude of an ac current provided to said ac mains power supply output such that an amount of power transferred to said ac mains power supply output is dependent on an amplitude of said sinusoidal voltage component on said energy storage capacitor, wherein said controlling is performed by controlling a dc-to-ac converter converting energy stored in said energy storage capacitor to ac power for said ac mains power supply output; and tracking a maximum power point of said photovoltaic dc source by controlling said dc-to-ac converter. - View Dependent Claims (18, 19, 20)
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Specification