Fault tolerant modular power supply system
First Claim
1. A fault tolerant modular power system comprising:
- (a) a plurality of power supplies, each having an output connected in parallel to supply current to a load, and each having the same nominal output voltage;
(b) current monitoring means associated with each of the power supplies, for monitoring a condition indicative of the magnitude of the current output by each, and operative to produce a signal corresponding to the magnitude of said current; and
(c) comparator means, connected to the current monitoring means and responsive to the signals said current monitoring means produce, for determining the difference between the current supplied by each power supply and at least one other power supply in the system that serves as a first order reference power supply, each power supply having a different first order reference power supply thereby producing a plurality of differential signals corresponding to said differences, each differential signal serving as a reference signal to control the output current of one of the power supplies causing the power supplies to have substantially equal output voltages and equal output currents.
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Accused Products
Abstract
A modular power supply system in which a plurality of power supply modules connected in parallel to a load contribute equal currents, even if one or more of the power supply modules fails. A first order fault tolerant modular power supply system includes three power supply modules (38, 40 and 42) connected in parallel to a load (32). The output current from each of the power supply modules is separately compared to the output current from one of the other power supply modules in a loop arrangement, using three control circuits (64, 66 and 68). A signal indicative of the current contributed by each pair of the power supply modules is input to the control circuit, producing a differential output signal used as a reference to control the output current from each of the power supply modules. Failure of any one of the modules does not affect the ability of the system to continue to supply substantially equal currents from the remaining two operating modules, so long as the total rated capacity of the power supply modules continuing to operate is not exceeded. Second and third order fault tolerant modular power supply systems (400 and 500) are also disclosed.
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Citations
21 Claims
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1. A fault tolerant modular power system comprising:
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(a) a plurality of power supplies, each having an output connected in parallel to supply current to a load, and each having the same nominal output voltage; (b) current monitoring means associated with each of the power supplies, for monitoring a condition indicative of the magnitude of the current output by each, and operative to produce a signal corresponding to the magnitude of said current; and (c) comparator means, connected to the current monitoring means and responsive to the signals said current monitoring means produce, for determining the difference between the current supplied by each power supply and at least one other power supply in the system that serves as a first order reference power supply, each power supply having a different first order reference power supply thereby producing a plurality of differential signals corresponding to said differences, each differential signal serving as a reference signal to control the output current of one of the power supplies causing the power supplies to have substantially equal output voltages and equal output currents. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fault tolerant modular power system comprising:
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(a) a plurality of N power supplies modules, arbitrarily arranged in a sequence 1 through N, each of the N power supply modules having; (i) an output connected in parallel to supply an output current to a load; (ii) a nominal output voltage that is variable in response to a control signal; and (iii) a rated power output greater than P/N, where P is the total power required by load; (b) means for sensing a condition indicative of the output current of each of the power supply modules, thereby producing an output current signal for each power supply module that serves as a first order reference power supply module, each power supply module having a different first order reference power supply module that is proportional to its output current; and (c) comparator means connected to each of the N power supply modules, for comparing the output current signal of each one of the power supply modules to the output current signal of at least an other of the N power supply modules, producing a difference signal proportional to the difference between the output currents of said one and at least said other of the power supply modules, and producing a plurality of control signals as a function of the difference signals, the control signs being connected to the power supply modules to control the output current provided by each of the N power supply modules, forcing the power supply modules to have substantially equal output voltages and substantially equal output currents, even upon failure of one or more of the power supply modules, so long as the rated capacity of any of the operating power supply modules is not exceeded. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. In a power supply system including a plurality of power supply modules connected in parallel to provide an output current to a load, each power supply module having an output voltage variable about the same nominal value, a method for controlling the output current of the power supply modules so that they are substantially equal, comprising the steps of:
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(a) monitoring the output current of the plurality of power supply modules, producing signals indicative of said current; (b) comparing the signals indicative of the output currents of selected pairs of the plurality of power supply modules that serves as one power supply module of each selected pair comprising a first order reference power supply module, each selected pair having a different first order reference power supply module thereby producing a difference signal indicative of the relative magnitude of said output currents; and (c) adjusting the output voltages of each of the plurality of power supply modules in response to the difference signals, so that the output current of each of the plurality of power supply modules is equal to the output current of at least one other of the plurality of power supply modules, thereby causing the plurality of power supply modules to substantially equally share the total current supplied to the load and to have substantially equal output voltages. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification