Controlled power supply system

Claim 1

A control system as set forth in claim 1 wherein said load is a DC motor.

Claim 13

A system for supplying current to an electrical load to control the load variable, said system comprising a load rectifier for conducting current of one polarity to said load, an AC power source connected across said load rectifier and said load whereby said rectifier is conditioned to conduct current of said one polarity to said load in one half-cycle and is nonconductive on the other half-cycle of the AC voltage thereacross, and means for controlling the turn on of said controlled rectifier within a half-cycle of said power source in accordance with a first cyclically varying signal and an error signal which is proportional to the difference between the actual value and the desired value of said load variable, means for providing the said error signal, means connected to said AC power source for providing therefrom the said cyclically varying signal in synchronism with said AC power source, the AC power across said rectifier being subject to conditions in said system rendering the anode-cathode of said rectifier of proper polarity for conducTion during the normally nonconductive half-cycle and said first cyclically changing signal being a sawtooth wave signal having a substantially straight line slope which increases from a low value toward a maximum value during a half-cycle of said source during which the rectifier is capable of conduction and reaches a maximum value in the subsequent half-cycle of the AC power source.

Claim 22

A system for supplying current to an electrical load to control a load variable, said system comprising an AC source, oppositely connected first and second contrOlled rectifiers connected to said AC source and to said load to control its energization by current of one polarity through said first controlled rectifier on one half-cycle of said AC source and by current of the opposite polarity through said controlled rectifier on the other half-cycle of said AC source, the AC voltage across said rectifiers being subject to electrical conditions in said systems which renders one said rectifier of proper polarity for conduction during the respective half-cycle in which the source has a polarity which would render the rectifier nonconductive and to the other rectifier nonconductive for at least a portion of the respective half-cycle of the source of a polarity to render the other rectifier conductive, sawtooth generator means connected to said AC source for generating therefrom phase-displaced first and second sawtooth waves in synchronism with said AC source each of which has a substantially straight line slope for substantially more than half of its complete cycle and a reference level for the remainder of its complete cycle, said first and second sawtooth waves each rising from a low level at the beginning of the half-cycle of the source in which the polarity of the source is such that the respective rectifier is normally biased for conduction and for a substantial portion of the following half-cycle, means for providing an error signal indicating the deviation of said load variable from its desired value, means for combining said error signal with each of said sawtooth waves, means connected to the control electrode of the first controlled rectifier for turning the latter on to conduct current of one polarity to said load when the combination of said error signal and said first sawtooth wave passes a predetermined value and the anode of said first controlled rectifier is positive with respect to its cathode, and means connected to the control electrode of said second controlled rectifier for turning the latter on to pass current of the opposite polarity to said load when the combination of said error signal and said second sawtooth wave passes a predetermined value and the anode of said second controlled rectifier is positive with respect to its cathode.