Protection circuits for hybrid power systems
First Claim
1. A system for powering a load comprising:
- a primary power device;
an energy storage device (ESD) coupled with the primary power device; and
second protection circuitry coupled with the ESD and the load.
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Accused Products
Abstract
The present invention provides a power management and protection system for a hybrid fuel cell system. The hybridization includes a fuel cell stack and an energy storage device (ESD) comprised of either batteries or ultracapacitors or both in parallel with the fuel cell for delivering power to an electrical load. The power management system provides voltage and current protection to the fuel cell stack, the ESD and the load by use of a two stage control system. The first stage limits the current being drawn from the fuel cell stack and the charging rate of the ESD and provides for the voltage output to be within a adjustable predetermined range to prevent an over-voltage condition on the ESD and the load and an under-voltage condition in the fuel cell stack. The second stage limits the current delivered to the load to an adjustable predetermined level and assures that the load will not see an under-voltage condition and in the case of a short circuit prevents rapid discharge of the ESD.
47 Citations
23 Claims
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1. A system for powering a load comprising:
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a primary power device;
an energy storage device (ESD) coupled with the primary power device; and
second protection circuitry coupled with the ESD and the load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system for powering a load comprising:
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a fuel cell stack;
an energy storage device (ESD) coupled with the fuel cell stack;
means for protecting the fuel cell stack from adverse voltage and current conditions;
means for protecting the ESD from adverse voltage and current conditions; and
means for protecting the load from adverse voltage and current conditions.
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21. A method of powering a load, comprising:
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providing an energy system comprising a fuel cell stack, an ESD, and protective circuitry;
sensing the fuel cell output current to determine if the current being drawn from the fuel cell stack is higher than the error limit;
sensing the fuel cell stack output voltage to determine if this voltage is above the low threshold error limit;
sensing the voltage applied to the energy storage devise to determine an over or under-voltage error condition;
sensing the current being delivered to the load to determine if the load current is higher than the error limit;
sensing the voltage being applied to the load to determine if the voltage is lower than the load low voltage error condition; and
controlling the voltage in the system in response to one or more of the sensing steps.
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22. A method of powering a load, comprising:
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providing an energy system comprising a fuel cell stack, an ESD, and protective circuitry;
sensing the fuel cell output current to determine if the current being drawn from the fuel cell stack is higher than the error limit;
sensing the fuel cell stack output voltage to determine if this voltage is above the low threshold error limit;
sensing the voltage applied to the energy storage devise to determine an over or under-voltage error condition;
sensing the current being delivered to the load to determine if the load current is higher than the error limit;
sensing the voltage being applied to the load to determine if the voltage is lower than the load low voltage error condition; and
controlling the current in the system in response to one or more of the sensing steps. - View Dependent Claims (23)
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Specification