Solar power system requiring no active control device
First Claim
1. A solar power system comprising:
- a photovoltaic array having a locus of peak power points for various insolation levels;
a voltage-dependent variable resistance load electrically connected to said array, said voltage-dependent variable resistance load having a voltage-current characteristic dependent only on voltage under normal operating conditions and such that it consumes less power than the peak power which is available from said photovoltaic array; and
a demand-dependent variable resistance load electrically connected in parallel with said voltage-dependent load, said demand-dependent variable resistance load changing the load on said photovoltaic array to operate within approximately 5 percent of said locus of peak power points over a range of demand-dependent variable resistance load power demands, making available for immediate consumption and for energy storage about 95 percent or more of the maximum power which said photovoltaic array may produce.
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Accused Products
Abstract
A solar power system has a photovoltaic array having a locus of peak power points for various insolation levels, a voltage-dependent variable resistance load such as a water electrolysis unit electrically connected to the array, and a demand-dependent variable resistance load such as a DC to AC inverter connected in parallel with the electrolysis unit. The electrolysis unit or other voltage-dependent variable resistance load has a voltage-current characteristic in which the operating point is displaced from the array'"'"'s peak power point for most insolation levels. The characteristic is displaced towards higher voltage-lower current operating points. The inverter may move the operating point of the photovoltaic array toward its peak power point when the load requires power. The system may be designed so that the array operates within about 5 percent of its peak power point over a wide range of inverter power demands. A fuel cell may be connected in parallel with the array to provide power to the inverter at low insolation levels, at night or in low sunlight. The fuel cell may use the hydrogen produced by the electrolysis unit for fuel. The total photovoltaic power made available by the system of this invention is generally greater than 95 percent and often greater than 98 percent of the maximum power which the photovoltaic array may produce for many insolation levels.
114 Citations
30 Claims
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1. A solar power system comprising:
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a photovoltaic array having a locus of peak power points for various insolation levels; a voltage-dependent variable resistance load electrically connected to said array, said voltage-dependent variable resistance load having a voltage-current characteristic dependent only on voltage under normal operating conditions and such that it consumes less power than the peak power which is available from said photovoltaic array; and a demand-dependent variable resistance load electrically connected in parallel with said voltage-dependent load, said demand-dependent variable resistance load changing the load on said photovoltaic array to operate within approximately 5 percent of said locus of peak power points over a range of demand-dependent variable resistance load power demands, making available for immediate consumption and for energy storage about 95 percent or more of the maximum power which said photovoltaic array may produce. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of increasing the useful power in a solar power system comprising the following steps:
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passing a portion of the current from a photovoltaic array having a locus of peak power points for various insolation levels of solar radiation through a voltage-dependent variable resistance load having a voltage-current characteristic in which the operating conditions of said voltage-dependent variable resistance load result in less power consumption than that which is available from said photovoltaic array at the peak power point of said photovoltaic array; and passing the remaining portion of the array current through a demand-dependent variable resistance load, said demand-dependent variable resistance load changing the load on said photovoltaic array to enable said photovoltaic array to operate within approximately 5 percent of said peak power points over a range of demand-dependent variable resistance load power demands, whereby about 95 percent and more of the maximum power which said photovoltaic array produces is transferred for useful purposes. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A solar power system comprising:
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a photovoltaic array; a water electrolysis unit which provides a voltage-dependent variable resistance load and produces hydrogen and oxygen electrically connected to said photovoltaic array; a demand-dependent variable resistance load electrically connected in parallel with said electrolysis unit; and a hydrogen storage chamber for storing hydrogen produced in said electrolysis unit.
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21. A solar power system comprising:
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a photovoltaic array; a voltage-dependent variable resistance load electrically connected to said photovoltaic array; a demand-dependent variable resistance load electrically connected in parallel with said voltage-dependent load; a fuel cell system electrically connected in parallel with said photovoltaic array; means for preventing current from flowing from said fuel cell system into said voltage-dependent variable resistance load or said photovoltaic array when the voltage of said fuel cell system is greater than or equal to the voltage of said photovoltaic array; and second current preventing means for preventing current from flowing from said photovoltaic array into said fuel cell system. - View Dependent Claims (22, 23)
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24. A method of increasing the useful power in a solar power system comprising the following steps:
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passing a portion of the current from a photovoltaic array having a locus of peak power points for various insolation levels of solar radiation through a voltage-dependent variable resistance load having a voltage-current characteristic in which the operating conditions of said voltage-dependent variable resistance load result in less power consumption than that which is available from said photovoltaic array at the peak power point of said photovoltaic array; passing a second portion of the array current through a demand-dependent variable resistance load, said demand-dependent variable resistance load changing the load on said photovoltaic array to enable said photovoltaic array to operate within approximately 5 percent of said peak power points over a range of demand-dependent variable resistance load power demands; enabling additional current to flow from a fuel cell system to said demand-dependent variable resistance load when the voltage of said fuel cell system is greater than or equal to the voltage of said photovoltaic array; and preventing current from flowing from said fuel cell system to said voltage-dependent variable resistance load and said photovoltaic array; whereby about 95 percent and more of the maximum power which said photovoltaic array produces is transferred for useful purposes. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method of increasing the useful power in a solar power system comprising the following steps:
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passing a portion of the current from the photovoltaic array through a water electrolysis unit which provides a voltage-dependent variable resistance load and produces hydrogen and oxygen; passing the remaining portion of the array current through a demand-dependent variable resistance load; and storing hydrogen produced in said electrolysis unit in a hydrogen storage chamber.
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Specification