Solar panel output enhancement circuit
First Claim
1. Apparatus for charging a battery exhibiting variable charge state voltage levels from the output of a solar cell energy source exhibiting variable voltage levels and substantially constant current, comprising:
- a step-down circuit including solid-state switch means actuable between conducting and non-conducting states, connectable in switching relationship with said source output, inductor means coupled with said switch means and connectable in charging relationship with said battery for conveying current thereto from said source when said switch means is in said conducting state, and unidirectional conducting means connectable in charging relationship with said battery for conveying current from said inductor means when said switch means is in said non-conducting state;
switch control means responsive substantially only to said source variable voltage levels for actuating said switch means, when enabled from a disabled condition, at switching rates controllably varied to substantially maintain a predetermined high value of said voltage levels exhibited by said source so as to optimize energy transfer to said battery; and
charge monitoring means responsive to said battery charge state voltage levels for selectively enabling said switch control means to effect charging of said battery to a fully charged condition.
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Accused Products
Abstract
A circuit for operation with solar panels exhibiting constant current and variable voltage characteristics. The power output of the panels is maximized by the circuit through the use of a step-down form of regulator which functions to monitor the peak voltage level of the panel and regulate with a switching type regulator in accordance therewith. Thus, peak voltage levels are maintained while current output to the load driven by the panels is enhanced. When employed for battery charging, the circuit includes a threshold selection network which identifies the nominal voltage rating of the battery under charge and provides appropriate adjustments to carry out a pulse charging technique. For start-up conditions wherein battery voltages may be below levels requisite to evaluate nominal rated voltages, a higher level charging voltage is applied for a predetermined short interval until adequate threshold is achieved to make appropriate determinations of rated voltage values. In one embodiment of the current boosting circuit, the gate capacitance of a field effect transistor type regulator switching component is taken advantage of to simplify circuit structure.
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Citations
44 Claims
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1. Apparatus for charging a battery exhibiting variable charge state voltage levels from the output of a solar cell energy source exhibiting variable voltage levels and substantially constant current, comprising:
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a step-down circuit including solid-state switch means actuable between conducting and non-conducting states, connectable in switching relationship with said source output, inductor means coupled with said switch means and connectable in charging relationship with said battery for conveying current thereto from said source when said switch means is in said conducting state, and unidirectional conducting means connectable in charging relationship with said battery for conveying current from said inductor means when said switch means is in said non-conducting state; switch control means responsive substantially only to said source variable voltage levels for actuating said switch means, when enabled from a disabled condition, at switching rates controllably varied to substantially maintain a predetermined high value of said voltage levels exhibited by said source so as to optimize energy transfer to said battery; and charge monitoring means responsive to said battery charge state voltage levels for selectively enabling said switch control means to effect charging of said battery to a fully charged condition. - View Dependent Claims (2, 3, 4, 5)
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6. Apparatus for charging a battery exhibiting variable charge state voltage levels from the output of an energy source exhibiting variable voltage levels and substantially constant current, comprising:
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a step-down circuit including solid-state switch means actuable between conducting and non-conducting states, connectable in switching relationship with said source output, inductor means coupled with said switch means and connectable in charging relationship with said battery for conveying current thereto from said source when said switch means is in said conducting state, and unidirectional conducting means connectable in charging relationship with said battery for conveying current from said inductor means when said switch means is in said non-conducting state; switch control means responsive to said source variable voltage levels for actuating said switch means, when enabled in response to a charge start signal from a disabled condition, to substantially maintain a predetermined high value of said voltage levels exhibited by said source, said switch control means being disabled in response to a charge stop signal; charge monitoring means including; level setting means responsive to said variable charge state voltage levels for providing a charge state signal; charge stop means responsive to said charge state signal and having first reference voltage network means for providing a first reference voltage having a value selected to derive a fully charged condition of said battery, and first comparator means responsive to said first reference voltage and to said charge state signal for deriving said charge stop signal; and charge start means responsive to said charge state signal and including second reference voltage network means for providing a second reference voltage having a predetermined value and second comparator means responsive to said second reference voltage and to said charge state signal for deriving said charge start signal when said charge start signal is at or below the level of said second reference voltage. - View Dependent Claims (7, 8, 9)
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10. An output enhancement circuit for driving a load from an energy source having an output exhibiting variable voltage levels including a peak voltage level and substantially constant current, comprising:
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a step-down circuit including solid-state switch means actuable between conducting and non-conducting states connectable with said source output, inductor means connectable intermediate said switch means and said load for conveying current thereto from said source when said switch means is in said conducting state, and unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said switch means is in said non-conducting state; source monitoring means responsive to said source variable voltage levels for providing a source monitoring output; control means responsive to said source monitoring output for actuating said switch means to derive a pulse width modulation of current from said source into said inductor means selected to substantially maintain said source exhibited peak voltage level so as to optimize energy transfer therefrom to said load. - View Dependent Claims (11, 12, 13)
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14. An output enhancement circuit for driving a load from an energy source having an output exhibiting variable voltage levels including a peak voltage level and substantially constant current, comprising:
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a step-down circuit including solid-state switch means having a field effect transistor with a gate exhibiting gate capacitance, said switch means being actuable between conducting and non-conducting states and connectable with said source output, inductor means connectable intermediate said switch means and said load for conveying current thereto from said source when said switch means is in said conducting state, and unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said switch means is in said non-conducting state; source monitoring means responsive to said source variable voltage levels for providing a source monitoring output; control means responsive to said source monitoring output for actuating said switch means to derive a pulse width modulation of current from said source into said inductor means selected to substantially maintain said source exhibited peak voltage level so as to optimize energy transfer therefrom to said load; and said control means comprising reference means for deriving a predetermined reference signal, and comparison network means responsive to said source monitoring output and said reference signal for alternately charging and discharging said gate capacitance to correspondingly derive said conducting and non-conducting states. - View Dependent Claims (15)
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16. Apparatus for charging a battery exhibiting variable charge state voltage levels and which is chargeable at one level of select first and second levels of charge from an energy source, comprising:
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step-down regulator means having a charging output connectable with said battery and including control means responsive to a charge signal, said charging output and to one of first and second threshold conditions for deriving on respective said first and second select levels of charge; charge monitoring means responsive to the charge state condition of said battery corresponding with one of third and fourth selected threshold conditions representing a fully charged state of said battery for deriving said charge signal; and threshold selecting network means responsive to said variable charge state voltage levels for deriving said first threshold condition and deriving said second and fourth threshold conditions when said charge state voltage level exceeds a predetermined maximum charging level determined with respect to said third threshold condition. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. An output enhancement circuit for driving a load from an energy source having an output exhibiting variable voltage levels and having a peak voltage level corresponding with maximum power output, and substantially constant current, comprising:
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energy storage means connectable across said output and chargeable at given rates by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage means and actuable between conducting and non-conducting states; inductor means connected with said solid-state switch means and connectable with said load for conveying current thereto from said source and energy storage means when said solid-state switch means is in said conducting state; unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; switch control network means having a first input responsive to a charge level responsive signal corresponding with the said charge levels of said energy storage means and a second input responsive to a reference level, and a switching output coupled with said solid-state switch means reference network means for deriving said reference level, said switch control network means being responsive to said charge level responsive signal and to said reference level to actuate said solid state switch means at frequencies varying in correspondence with said given rate of charge of said energy storage means to substantially maintain said source peak voltage level. - View Dependent Claims (24)
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25. An output enhancement circuit for driving a load from an energy source having an output exhibiting variable voltage levels including a peak voltage level and substantially constant current, comprising:
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energy storage means connectable across said output and chargeable by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage means and actuable between conducting and non-conducting states; inductor means connected with said solid-state switch means and connectable with said load for conveying current thereto from said source and energy storage means when said solid-state switch means is in said conducting state; unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; and switch control netwsork means having an operational amplifier with a first input responsive to a charge level responsive signal corresponding with the said charge level of said energy storage means and a second input responsive to a reference level, and a switching output coupled with said solid-state switch means reference network means for deriving said reference level, said switch control network means actuating said solid-state switch means into conduction when said storage level responsive signal exceeds a said reference level and actuating said switch means into said non-conducting state when said charge level responsive signal is below said reference level. - View Dependent Claims (26, 27)
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28. A solar panel assembly comprising;
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a panel component having a photovoltaic region mounted upon a supportive substrate, and photovoltaic region having a panel output exhibiting variable voltage levels and substantially constant current and having a peak voltage level corresponding with the maximum power output of said panel component; electrical junction means mounted with said panel for receiving said panel output and having external output terminal; an output enhancement circuit mounted with said electrical junction means including; energy storage means connectable across said panel output and chargeable at given rates by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage means and actuable between conducting and non-conducting states; inductor means connected with said solid-state switch means and with said external output terminals for conveying current thereto from said source and energy storage means when said solid-state switch means is in said conducting state; unidirectional conducting means connected with said external output terminals for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; switch control network means having a first input responsive to a charge level responsive signal corresponding with said charge levels of said energy storage means and a second input responsive to a reference level, and a switching output coupled with said solid-state switch means, said switch control network means being responsive to said charge level responsive signal and to said reference level to actuate said solid state switch means at frequencies varying in correspondence with said given rate of charge of said energy storage means to substantially maintain said panel peak voltage level.
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29. A solar panel assembly comprising:
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a panel component having a photovoltaic region mounted upon a supportive substrate, said photovoltaic region having a panel output exhibiting variable voltage levels including a peak voltage level and substantially constant current; electrical junction means mounted with said panel for receiving said panel output and having an external output terminal; an output enhancement circuit mounted with said electrical junction means including; energy storage means connectable across said panel output and chargeable by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage menas and actuable between conducting and non-conducting states;
inductor means connected with said solid-state switch means and with said external output terminals for conveying current thereto from said source and energy storage means when said solid-state switch menas is in said conducting state;unidirectional conducting means connected with said external output terminals for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; switch control network means having an operational amplifier with a first input responsive to a charge level responsive signal corresponding with the said charge levels of said energy storage means and a second input responsive to a reference level, and a switching output coupled with said solid-state switch means, said switch control network means actuating said solid-state switch means into conduction when said storage level responsive signal exceeds a said reference level and actuating said switch means into said non-conducting state when said charge level responsive signal is below said reference level. - View Dependent Claims (30, 31)
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32. An output enhancement circuit for driving a load of given current demands from an energy source having an output characteristic exhibiting variable voltage levels and a substantially constant current value and having a peak voltage level corresponding with the maximum power output of said source, comprising:
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energy storage means connectable across said source and chargeable at given rates by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage means and actuable between conducting and non-conducting states; inductor means connected with said solid-state switch means and connectable with said load for conveying current thereto from said source and energy storage means when said solid-state switch means is in said conducting state; unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; switch control network means including an operational amplifier exhibiting a given hysteresis characteristic, having first and second inputs, and a switching output coupled with said switch means, means deriving a reference level for assertion at said amplifier second input, means for applying charge levels corresponding with said source voltage levels at said amplifier first input, a feedback network including feedback capacitance means coupled between said switching output and said first input, said switch control network being responsive to said charge level at said first input and to said reference level to actuate said solid-state switch means into conduction when said charge level at said first input exceeds a said reference level and actuating said switch means into said non-conducting state when said charge level is below said reference level, the said switching actuation being developed in accordance with said hysteresis characteristic, and said means for applying charge levels and said reference level being selected for actuating said switch means at frequencies varying in correspondence with said given rate of charge said energy storage means to substantially maintain said source peak voltage level; and said feedback capacitance means having a capacitance value selected to enhance the rate of said switching actuation during the occurrence of elevated said load current demands. - View Dependent Claims (33, 34, 35, 36)
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37. An output enhancement circuit for driving a load from an energy source having output exhibiting variable voltage levels and substantially constant current, and having a peak voltage corresponding with maximum power output comprising:
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energy storage means connectable across said output and chargeable at given rates by said current to variable charge levels; solid-state switch means connected in energy transfer relationship with said energy storage means and actuable between conducting and non-conducting states; inductor means connected with said solid-state switch means and connectable with said load for conveying current thereto from said source and energy storage means when said solid-state switch means is in said conducting state; unidirectional conducting means connectable with said load for conveying current thereto from said inductor means when said solid-state switch means is in said non-conducting state; switch control network means having a first input responsive to a charge level responsive signal corresponding with the said charge levels of said energy storage means and a second input responsive to a reference level, and a switching output coupled with said solid-state switch means, said switching output including emitter-follower stage means for enhancing the current values assertable therefrom, and said switch control network means being responsive to said charge level responsive signal and to said reference level to actuate said solid state switch means at frequencies varying in correspondence with said given rate of charge of said energy storage means to substantially maintain said source peak voltage level. - View Dependent Claims (38, 39, 40)
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41. An output enhancement circuit for driving a load from an energy source having an output exhibiting variable voltage levels and substantially constant current and having a peak voltage level corresponding with maximum power output, comprising:
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first energy storage means connectable across said output and chargeable at given rates by said current to variable charge levels; first solid-state switch means connected in energy transfer relationship with said first energy storage means and actuable between conducting and non-conducting states; first inductor means connected with said solid-state switch means and connectable with said load for conveying current thereto from said source and first energy storage means when said solid-state switch means is in said conducting state; first uni-directional conducting means connectable with said load for conveying current thereto from said inductor means when said first solid-state switch means is in said non-conducting state; switch control network means having a first input responsive to a charge level responsive signal corresponding with the said charge levels of said first energy storage means and a second input responsive to a reference level, and a switching output coupled with said first solid-state switch means, said switch control network means being responsive to said charge level responsive signal and to said reference level to actuate said solid state switch means at frequencies varying in correspondence with said given rate of charge of said energy storage means to substantially maintain said source peak voltage level; a supplementary power stage including; second energy storage means connectable across said output; second solid-state switch means connected in energy transfer relationship with said second energy storage means and actuable between conducting and non-conducting states; second inductor means connected with said second solid-state switch means and connectable with said load for conveying current thereto from said source and second energy storage means when said second solid-state switch means is in said conducting state; second uni-directional conducting means conectable with said load for conveying current thereto from said inductor means when said second solid-state switch means is in said non-conducting state; and means for connecting said switch control network means switching output with said second solid-state switch means, said control network means actuating said second solid-state switch means into conduction when said storage level responsive signal exceeds said reference level and actuating said second switch means into said non-conducting state when said charge level responsive signal is below said reference level. - View Dependent Claims (42, 43, 44)
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Specification