Precharging load capacitor for power-factor-corrected AC-to-DC power supply
AssigneeLockheed Martin Corporation
InventorKeng-Chih Wu
Life of this patent
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Abstract
A power supply for a capacitive-resistive load includes plural paralleled phase correcting modules together with current sharing controllers for tending to equalize their currents. Each module is provided with a diode, poled to prevent forward current from flowing in the return current path, for aiding in equalizing module currents. Surge currents are reduced by a single saturable reactor coupled to the combined outputs of current sharing controllers, thereby avoiding the need for soft-start in each controller. A precharging path extends from a source of pulsating direct voltage to the load, for precharging the load capacitance at turn-on.
Claims11
An electrical apparatus for powering a load including a resistive and a capacitive component, said electrical apparatus comprising:
- a source of pulsating direct voltage:
- a first plurality of power factor correction units coupled to said source of direct voltage for converting said pulsating direct voltage into a direct voltage at an output port and for tending to maintain the current through said source of pulsating direct voltage in-phase with said pulsating direct voltage;
- a plurality equal to said first plurality of current sharing controllers, each of which includes a port coupled to said output port of one of said power factor correction units, and also includes an output port in common with all output ports of said current sharing controllers, said current sharing controllers being subject to surge current when said direct voltage of the associated one of said power factor correction units is coupled to said capacitive component of said load at turn-on;
- and
- controllable switch means coupled to said source of pulsating direct voltage and to said load, for precharging said capacitive component of said load.
An electrical apparatus for powering a load including a resistive and a capacitive component, said electrical apparatus comprising:
- a source of pulsating direct voltage:
- a first plurality of boost power factor correction units coupled to said source of direct voltage for converting said pulsating direct voltage into a direct voltage at an output port and for tending to maintain the current through said source of pulsating direct voltage in-phase with said pulsating direct voltage;
- a plurality equal to said first plurality of current sharing controllers, each of which includes a port coupled to said output port of one of said power factor correction units, and also includes an output port in common with all output ports of said current sharing controllers, said current sharing controllers being subject to a surge current when said direct voltage of the associated one of said power factor correction units is coupled to said capacitive component of said load at turn-on;
- and
- unidirectional current conducting means coupled to said source of pulsating direct voltage and to said load, poled for charging said capacitive component of said load when said pulsating direct voltage exceeds the load voltage.
Dependencies are inferred from the claim text.