Fault commutation system for static inverters
AssigneeEaton Corporation
InventorFrank Nicholas Klein
Life of this patent
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Abstract
An inverter system having a dc input and an ac output has a fault sensor and switching provisions for diverting current to an additional path away from overloaded semiconductors of the inverter upon a fault. The system has a resonant inductance and capacitance circuit at the dc input, whose capacitance discharges through the inductance upon a fault and recharges with an opposite polarity to apply the reverse polarity to semiconductors of the inverter in an attempt to interrupt the fault. Initially the discharge of the capacitance is blocked by a second switching circuit until the fault sensor produces a fault indication signal, so that no portion of the initial charge of the capacitance is wasted by discharging into the faulting semiconductors of the inverter before the current diverting path is established.
Claims20
An inverter system that supplies power to an ac load from a dc source comprising inverter means having input terminals connected with said dc source and output terminals connectable for delivering the ac power to the load and having a plurality of inverter semiconductor means each periodically rendered conductive and non-conductive, sensing means for sensing a fault in which at least some of said inverter semiconductor means experience a current overload and for producing a fault indication signal, first switching circuit means connected with said fault sensor and responsive to said fault indication signal and connected for diverting thereupon at least a portion of current from said overloaded inverter semiconductor means, capacitance means for storing electrical energy, means for charging said capacitance means to a first polarity, inductance means for storing electrical energy and connected in series with said capacitance means, second switching circuit means connected in series with said capacitance means and said inductance means for blocking and unblocking current flow therethrough, the series circuit of said capacitance means, inductance means and second switching circuit means being connected in parallel with said dc source, said second switching circuit means being responsive to said fault indication signal not earlier than said current portion is diverted to discharge said capacitance means by current flow through said second switching means and said inductance means and to recharge said capacitance means with polarity opposite from said first polarity, said capacitance means being connected with said inverter input terminals so as to apply said opposite polarity to said inverter input terminals, whereby an attempt is made to interrupt said fault.
An inverter system that supplies power to an ac load from a dc source comprising inverter means having output terminals connected for delivering the ac power to the load, said inverter means including a plurality of inverter semiconductor means each periodically rendered conductive and non-conductive, sensing means for sensing a fault in which at least some of said inverter semiconductor means have a current overload and for producing a fault indication signal thereupon, first switching circuit means connected with said fault sensing means and responsive to said fault indication signal and connected for diverting thereupon at least a portion of current from said overloaded inverter semiconductor means, capacitance means for storing electrical energy, means for charging said capacitance means to a first polarity, inductance means for storing electrical energy and connected in series with said capacitance means, second switching circuit means connected in series with said capacitance means and said inductance means for blocking and unblocking current therethrough, said second switching circuit means being responsive to said fault indication signal not earlier than said current portion is diverted to discharge said capacitance means by capacitor current flowing through said second switching means and said inductance means and flowing at least in part through said first switching circuit means to recharge said capacitance means with polarity opposite from said first polarity, said capacitance means being connected with said inverter input terminals so as to apply said opposite polarity to said inverter input terminals, whereby an attempt is made to interrupt said fault.
An inverter system that supplies power to an ac load from a dc source comprising inverter means having an input connected with said dc source and having output terminals connected for delivering the ac power to the load, said inverter means including a plurality of inverter semiconductor means each periodically rendered conductive and non-conductive, sensing means for sensing a fault in which at least some of said inverter semiconductor means have a current overload and for producing a fault indication signal, first switching circuit means connected with said fault sensor and responsive to said fault indication signal for diverting thereupon at least a portion of current from said overloaded inverter semiconductor means, capacitance means for storing electrical energy, means for charging said capacitance means to a first polarity, inductance means for storing electrical energy and in series with said capacitance means, second switching circuit means connected in series with said capacitance means and said inductance means for blocking and unblocking current flow therethrough said second switching circuit means being responsive to said fault indication signal not earlier than said current portion is diverted to discharge said capacitance means by capacitor current flowing through said second switching circuit means and said inductance means and to recharge said capacitance means with polarity opposite from said first polarity, said capacitance means being connected with said inverter input terminals so as to apply said opposite polarity to said inverter input, whereby an attempt is made to interrupt said fault.
Dependencies are inferred from the claim text.