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US 4,225,911 AGranted
Apparatus and method for reducing overvoltage transients on the outputs of a VSCF system
AssigneeGeneral Electric Company
InventorHarold G. Carlson
Life of this patent
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AssigneeGeneral Electric Company
InventorHarold G. Carlson
Estimating the term…
An apparatus and method for reducing the overvoltage transients present on the alternating current power signals provided by the cycloconverters of a variable speed constant frequency (VSCF) system during the first several cycles of the alternating current after a load reduction or no-load condition occurs. An overvoltage transient reduction circuit is connected to each of the plurality of D.C. control signals provided by the phase voltage regulators to the waveform generator of a conventional VSCF system. The overvoltage transient circuit and method of the present invention senses the current amplitude level in each of the alternating current power signals in the VSCF system, and automatically reduces the voltage amplitude levels of the D.C. control signals provided by the phase voltage regulators to a preselected lower level within one-half cycle of the alternating current after a load reduction occurs. This reduction in the amplitude level of the D.C. control signals is maintained by the circuit and method of the present invention until the voltage regulating control loop of the conventional VSCF system can again assume control of the voltage levels of the alternating current power signals.
A cycloconverter of the type having a source of multiphase electric power, a plurality of cycloconverter power source means connected to said multiphase electric power, each said cycloconverter power source means responsive to a gating signal for providing one of a plurality of alternating current power signals of a preselected frequency, first means responsive to each of said alternating current power signals for providing a plurality of reference signals of said preselected frequency having voltage amplitudes controlled in accordance with voltage levels of said alternating current power signals, a plurality of gating signal means, each of said gating signal means having an input responsive to one of said reference signals for providing said gating signal to one of said cycloconverter power source means, the improvement comprising:
A cycloconverter of the type having a source of multiphase electric power, a plurality of cycloconverter power source means connected to said multiphase electric power, each said cycloconverter power source means responsive to a gating signal for providing one of a plurality of alternating current power signals of a preselected frequency, first means responsive to each of said alternating current power signals for providing a plurality of reference signals of said preselected frequency having voltage amplitudes controlled in accordance with voltage levels of said alternating current power signals, a plurality of gating signal means, each of said gating signal means having an input responsive to one of said reference signals for providing said gating signal to one of said cycloconverter power source means, the improvement comprising:
In a cycloconverter method of the type comprising the steps of generating multiphase electric power of a variable frequency, applying said multiphase electric power to a plurality of cycloconverter power source means for providing in accordance with a plurality of gating signals a plurality of alternating current power signals of a preselected frequency, sensing said alternating current power signals for providing a plurality of reference signals of said preselected frequency having voltage amplitudes controlled in accordance with voltage levels of said alternating current power signals, generating said gating signals in accordance with said reference signals, and applying said gating signals to said cycloconverter power source means, the improvement comprising the steps of:
Dependencies are inferred from the claim text.