Adjustable frequency current source power supply of the inverter type

Claim 2

An inverter interposable between a source of electric energy and the terminals of an alternating current device for effecting current energization of the periodic type in the device to control the operative condition thereof, such a device having a reactance which is sufficiently small as to permit alteration of the current in a time interval which is short compared to the period of the current, the electrical energy source providing a unidirectional output current of substantially a desired magnitude, said inverter comprising: a. an input connectable to said electrical energy source and an output connectable to the terminals of said alternating current device; b. at least a pair of parallel current paths between the input and output of the inverter, each of said current paths containing a thyristor and a diode connected in series therewith; c. a control means coupled to the thyristor for cyclically placing the thyristor in the cUrrent conductive state for providing current energization of a periodic type in said device; a capacitor connected across said current paths between a first point in each said current path intermediate the thyristor and the diode of each pair for transferring current between said paths and for placing said thyristors in a nonconductive state; and d. a reactor and a diode means connected in series between said first point in each said current path and said input of said inverter, said reactor resonantly discharging a corresponding said capacitor connected between a pair of current paths thereby minimizing the time required to transfer current between paths.

Claim 3

The inverter as claimed in claim 1 wherein said diode means has a polarity to conduct with reverse voltage applied to the thyristor in said corresponding current path.

Claim 4

The inverter as claimed in claim 2 wherein said diode means conducts for less than half of the conduction period of one thyristor.

Claim 5

The inverter as claimed in claim 1 wherein current begins to flow through said reactor at substantially the same time whenever current begins to flow through a thyristor in another of said current paths.

Claim 6

The inverter as claimed in claim 4 wherein the period of current flow through reactor is determined by the L-C time constant of said reactor and said corresponding capacitor.

Claim 7

The inverter as claimed in claim 5 wherein current flowing through said reactor also flows through a thyristor in another of said current paths thereby discharging said corresponding capacitor in a minimum amount of time.

Claim 8

A power supply interposable between a source of electric energy and the terminals of an alternating current device for effecting current energization of a periodic type to control the operative condition thereof, said device having a reactance which is sufficiently small as to permit alteration of the current in a time interval which is short compared to the period of the current, said power supply comprising: a. a power source having an input connectable to the electrical energy source, said power source providing a unidirectional output current of substantially a desired magnitude at the output thereof; b. an inductor connected to the output of said power source for maintaining the output current at the desired magnitude, said inductor forming, with said power source a unidirectional current source; and c. an invertor having an input connected to said current source and an output connectable to the terminals of said current device, at least a pair of parallel current paths between the input and output of the invertor, each of said current paths containing a thyristor and a diode connected in series therewith, a control means coupled to the thyristor for cyclically placing said thyristor in a current conductive state for providing current energization of the periodic type in said device, a capacitor connected across said current paths between a first point in each said current path intermediate said thyristor and said diode of each pair for transferring current between said paths and for placing said thyristors in a non-conductive state, and a reactor and a diode means connected in series between said first point in each said current path and said input of said inverter, said reactor resonantly discharging a corresponding capacitor thereby minimizing the time required by said corresponding capacitor to transfer current between said paths.

Claim 9

A power supply interposable between a source of electric energy and the terminals of an alternating current device for effecting current energization of a periodic type to control the operative condition thereof, said device having a reactance which is sufficiently small as to permit alteration of the current in a time interval which is short compared to the period of the current, said power supply comprising: a. a power source having an input connectable to the electrical energy source, said power source providing a unidirectional output current of substantially a desired magnitude at the output thereof; b. an inductor connected to the output of said power source for maintaining the output current at the desired magnitude, said inductor forming, with said power source a unidirectional current source; and c. an invertor having an input connected to said current source and an output connectable to the terminals of said current device, at least a pair of parallel current paths between the input and output of the invertor, each of said current paths containing a thyristor and a diode connected in series therewith, a control means coupled to the thyristor for cyclically placing said thyristor in a current conductive state for providing current energization of the periodic type in said device, a capacitor connected across said current paths between a first point in each said current path intermediate said thyristor and said diode of each pair for transferring current between said paths and for placing said thyristors in a non-conductive state, and a reactor and a diode means connected in series between said first point in each said current path and said input of said inverter, said reactor resonantly discharging a corresponding capacitor thereby minimizing the time required by said corresponding capacitor to transfer current between said paths.