Ferroresonant transformer battery charger circuit

Claim 2

A battery charger circuit for charging a battery from an AC power source, said battery charger circuit comprising a ferroresonant transformer having a primary winding connected to an AC power source and a plurality of secondary windings; a first rectifier circuit connected between the secondary windings of the transformer and one terminal of the battery for providing a first level of voltage; an impedance; and a second rectifier circuit connected via the impedance in piggyback with the first rectifier circuit between the secondary windings of the transformer and the one terminal of the battery for providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic, the impedance comprising a resistor connected between the second rectifier circuit and the battery for determining the finish rate current of the battery charger characteristic and the start rate of the battery charger characteristic being determined by the inherent ferroresonant transformer characteristic.

Claim 3

A battery charger circuit for charging a battery from an AC power source, said battery charger circuit comprising a ferroresonant transformer having a primary winding connected to an AC power source and a plurality of secondary windings; a first rectifier circuit connected between the secondary windings of the transformer and one terminal of the battery for providing a first level of voltage; an impedance; a second rectifier circuit connected via the impedance in piggy-back with the first rectifier circuit between the secondary windings of the transfOrmer and the one terminal of the battery for providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic; and an inductor connected between the secondary windings of the transformer and the second rectifier circuit for determining the finish rate current of the battery charger characteristic.

Claim 4

A battery charger circuit for charging a battery from an AC power source, said battery charger circuit comprising a ferroresonant transformer having a primary winding connected to an AC power source and a plurality of secondary windings; a first rectifier circuit connected between the secondary windings of the transformer and one terminal of the battery for providing a first level of voltage; an impedance; a second rectifier circuit connected via the impedance in piggy-back with the first rectifier circuit between the secondary windings of the transfOrmer and the one terminal of the battery for providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic; and an inductor connected between the secondary windings of the transformer and the second rectifier circuit for determining the finish rate current of the battery charger characteristic.

Claim 5

A battery charger circuit for charging a battery from an AC power source, said battery charger circuit comprising a ferroresonant transformer having a primary winding connected to an AC power source and a plurality of secondary windings, said transformer including magnetic shunts separating the secondary windings from the primary winding and a ferrocapacitor connected across the secondary windings in series and the secondary windings include a first winding having a center tap and a pair of end terminals, a second winding having an end terminal connected to one end terminal of the first winding and another end terminal, a third winding having an end terminal connected to the other end terminal of the first winding and another end terminal and a fourth winding having an end terminal connected to the other end terminal of the second winding; a first rectifier circuit connected between the secondary windings of the transformer and one terminal of the battery for providing a first level of voltage; an impedance; and a second rectifier circuit connected via the impedance in piggy-back with the first rectifier circuit between the secondary windings of the transformer and the one terminal of the battery for providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic.

Claim 6

A battery charger circuit for charging a battery from an AC power source, said battery charger circuit comprising a ferroresonant transformer having a primary winding connected to an AC power source and a plurality of secondary windings, said transformer including magnetic shunts separating the secondary windings from the primary winding and a ferrocapacitor connected across the secondary windings in series and the secondary windings include a first winding having a center tap and a pair of end terminals, a second winding having an end terminal connected to one end terminal of the first winding and another end terminal, a third winding having an end terminal connected to the other end terminal of the first winding and another end terminal and a fourth winding having an end terminal connected to the other end terminal of the second winding; a first rectifier circuit connected between the secondary windings of the transformer and one terminal of the battery for providing a first level of voltage; an impedance; and a second rectifier circuit connected via the impedance in piggy-back with the first rectifier circuit between the secondary windings of the transformer and the one terminal of the battery for providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic.

Claim 7

A battery charger circuit as claimed in claim 3, wherein the first rectifier circuit comprises first and second diodes having anodes connected to the end terminals of the first secondary winding in a first full-wave rectifier bridge and cathodes connected in common to the positive polarity terminal of the battery and means connecting the center tap of the first secondary winding to the negative polarity terminal of the battery.

Claim 8

A battery charger circuit as claimed in claim 4, wherein the second rectifier circuit comprises third and fourth diodes having anodes connected to the other end terminals of the second and third secondary windings in a second full-wave rectifier bridge and cathodes connected in common to the positive polarity terminal of the battery via the impedance.

Claim 9

A battery charger circuit as claimed in claim 5, further comprising an inductor having a winding connected between the anode of the third diode and the other end terminal of the third secondary winding and another winding connected between the anode of the fourth diode and the other end terminal of the second secondary winding for determining the finish rate current of the battery charger characteristic.

Claim 10

A battery charger circuit as claimed in claim 5, further comprising time control means connected to the primary winding of the transformer for deenergizing the transformer after a predetermined period of time.

Claim 11

A battery charger circuit for charging a battery from a three phase AC power source, said battery charger circuit comprising first and second ferroresonant transformers having primary windings connected to each other in Scott-T connection and connected to a three phase AC power source, each of the transformers having a plurality of secondary windings; a first rectifier circuit connected between the secondary windings of the first transformer and one terminal of the battery; impedance means; a second rectifier circuit including the impedance means connected in piggy-back with the first rectifier circuit between the secondary windings of the first transformer and the one terminal of the battery; a third rectifier circuit connected between the secondary windings of the second transformer and the one terminal of the battery, the first and third rectifier circuits pRoviding a first rate of voltage, the first and third rectifier circuits providing a first level of voltage; and a fourth rectifier circuit including the impedance means connected in piggy-back with the third rectifier circuit between the secondary windings of the second transformer and the one terminal of the battery, the second and fourth rectifier circuits providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic.

Claim 12

A battery charger circuit for charging a battery from a three phase AC power source, said battery charger circuit comprising first and second ferroresonant transformers having primary windings connected to each other in Scott-T connection and connected to a three phase AC power source, each of the transformers having a plurality of secondary windings; a first rectifier circuit connected between the secondary windings of the first transformer and one terminal of the battery; impedance means; a second rectifier circuit including the impedance means connected in piggy-back with the first rectifier circuit between the secondary windings of the first transformer and the one terminal of the battery; a third rectifier circuit connected between the secondary windings of the second transformer and the one terminal of the battery, the first and third rectifier circuits pRoviding a first rate of voltage, the first and third rectifier circuits providing a first level of voltage; and a fourth rectifier circuit including the impedance means connected in piggy-back with the third rectifier circuit between the secondary windings of the second transformer and the one terminal of the battery, the second and fourth rectifier circuits providing a second higher level of voltage thereby providing a close to ideal battery charger characteristic.

Claim 13

A battery charger circuit as claimed in claim 8, further comprising a first inductor connected between the secondary windings of the first transformer and the second rectifier circuit and a second inductor connected between the secondary windings of the second transformer and the fourth rectifier circuit, the first and second inductors determining the finish rate current of the battery charger characteristic.

Claim 14

A battery charger circuit as claimed in claim 8, wherein each of the first and second transformers includes magnetic shunts separating the secondary windings from the primary winding and a ferrocapacitor connected to the secondary windings and the secondary windings of each of the first and second transformers include a first winding having a center tap and a pair of end terminals, a second winding having an end terminal connected to one end terminal of the first winding and another end terminal, a third winding having an end terminal connected to the other end terminal of the first winding and another end terminal and a fourth winding having an end terminal connected to the other end terminal of the second winding.

Claim 15

A battery charger circuit as claimed in claim 8, wherein the start rate of the battery charger characteristic is determined by the inherent ferroresonant transformer characteristic and the finish rate current of the battery charger characteristic is determined by the impedance means.

Claim 16

A battery charger circuit as claimed in claim 10, wherein each of the first and third rectifier circuits comprises first and second diodes having anodes connected to the end terminals of the first secondary winding of the first and second transformers, respectively, in a first full-wave rectifier bridge and cathodes connected in common to the positive polarity terminal of the battery and means connecting the center tap of the first secondary winding of the first and second transformers to the negative polarity terminal of the battery.

Claim 17

A battery charger circuit as claimed in claim 12, wherein each of the second and fourth rectifier circuits comprises third and fourth diodes having anodes connected via the impedance means to the other end terminals of the second and third secondary windings of the first and second transformers, respectively, in a second full-wave rectifier bridge and cathodes connected in common with the cathodes of the first and second diodes to the positive polarity terminal of the battery.

Claim 18

A battery charger circuit as claimed in claim 13, further comprising first and second inductors, the first inductor having a winding connected between the anode of the third diode and the other end terminal of the third secondary winding of the first transformer and another winding connected between the anode of the fourth diode and the other end terminal of the secondary winding of the first transformer, and the second inductor having a winding connected between the anode of the third diode and the other end terminal of the third secondary winding of the second transformer and another winding connected between the anode of the fourth diode and the other end terminal of the secondary winding of the second transformer, the inductors determining the finish rate current of the battery charger characteristic.

Claim 19

A battery charger circuit as claimed in claim 13, further comprising time control means connected to the primary windings of first and second transformers for deenergizing the transformers after a predetermined period of time.