Dual voltage power supply system for vehicles

Claim 2

In an electrical system for a vehicle, said system being of the type including a DC generator having a DC output, a first load circuit including a battery and one or more load devices adapted to be powered by DC electricity at a voltage in a first voltage range corresponding to the rated voltage of the battery, and a second load circuit including one or more load devices designed to be powered by a DC electricity at a voltage in a second voltage range extending substantially higher than said first voltage range, the improvement comprising: a first regulator having an input coupled with a DC output of said DC generator and having an output coupled with said first load circuit, said first regulator including means for converting power received at said input to power at a voltage in said first voltage range, and a second regulator for controlling said generator to produce a DC voltage meeting the requirements of said second load circuit, an output of said DC generator being coupled with said second load circuit.

Claim 3

The invention as defined in claim 1 wherein said first regulator comprises: a switching means and an inductor connected in series with said first load circuit, a unidirectional conductive means connected in parallel with the series combination of said inductor and said first load circuit, and control means for controlling said switching means.

Claim 4

The invention as defined in claim 2 wherein said switching means is a transistor.

Claim 5

The invention as defined in claim 2 wherein said unidirectional conductive means is a diode.

Claim 6

The invention as defined in claim 2 including: recirculating switch means connected to recirculate inductor current, a control circuit responsive to the voltage across said first load circuit operatively connected to said recirculating switching means, whereby inductor current recirculation is enabled when required to prevent the voltage across said first load circuit from exceeding a predetermined value.

Claim 7

The invention a defined in claim 5 in which said recirculating switch means is a transistor.

Claim 8

The invention as defined in claim 1 wherein said second regulator regulates the generator output voltage at a predetermined maximum voltage in said second voltage range when the rotation rate of said DC generator is great enough for said maximum voltage to be achieved.

Claim 9

The invention as defined in claim 1 wherein said DC generator has a field winding of controllable energization, said second regulator being coupled with said field winding, and wherein said field energization is provided by said DC generator and wherein said regulator includes means for limiting the fraction of the time that said DC generator is connected to the field winding in a manner dependent upon generator output voltage whereby maximum field current is limited.

Claim 10

The invention as defined in claim 8 wherein the fraction of the time that the field winding is connected to the generator output is limited to a value substantially inversely proportional to the generator output voltage whereby the limiting field energization is substantially independent of the generator output voltage.

Claim 11

The invention as defined in claim 7 including overvoltage protection means for preventing the voltage across said first load circuit from exceeding a predetermined value.

Claim 12

The invention as defined in claim 10 wherein said overvoltage protection means comprises a capacitor connected across said first load circuit.

Claim 13

The invention as defined in claim 2 including overvoltage protection means for preventing the voltage across said first load circuit from exceeding a predetermined value, said overvoltage protection means including a second switching means connected across said inductor.

Claim 14

In an electrical system for a vehicle, said system being of the type including a DC generator having a DC output, a storage battery adapted to be charged from the generator, a first load circuit including said storage battery and one or more load devices designed to be powered by DC electricity at a voltage in a first voltage range corresponding to the rated voltage of the battery, and a second load circuit including one or more load devices designed to be powered by DC electricity at a voltage in a second voltage range extending substantially higher than said first voltage range, the improvement comprising: a regulator for controlling said generator to produce an output voltage meeting the requirements of said second load circuit, a DC output of said DC generator being coupled with said second load circuit, a DC output of said DC generator being coupled with a series combination of a switching means, an inductor and said first load circuit, a unidirectional conductive means connected in parallel with the series combination of said inductor and said first load circuit, and control means for controlling said switching means.

Claim 15

In an electrical system for a vehicle, said system being of the type including a DC generator having a DC output, a storage battery adapted to be charged from the generator, a first load circuit including said storage battery and one or more load devices designed to be powered by DC electricity at a voltage in a first voltage range corresponding to the rated voltage of the battery, and a second load circuit including one or more load devices designed to be powered by DC electricity at a voltage in a second voltage range extending substantially higher than said first voltage range, the improvement comprising: a regulator for controlling said generator to produce an output voltage meeting the requirements of said second load circuit, a DC output of said DC generator being coupled with said second load circuit, a DC output of said DC generator being coupled with a series combination of a switching means, an inductor and said first load circuit, a unidirectional conductive means connected in parallel with the series combination of said inductor and said first load circuit, and control means for controlling said switching means.

Claim 16

The invention as defined in claim 13 including: a control circuit responsive to the voltage across said first load circuit and operatively coupled with said switching means for switching said switching means to a nonconductive state in response to a voltage across said first load circuit greater than a predetermined voltage.

Claim 17

The invention as defined in claim 13 wherein said control means is responsive to the voltage across said first load circuit.

Claim 18

The invention as defined in claim 13 wherein said switching means is a transistor.

Claim 19

The invention as defined in claim 13 wherein said unidirectional conductive means is a diode.

Claim 20

The invention as defined in claim 13 including: recirculating switch means connected to recirculate inductor current, a control circuit responsive to the voltage across said first load circuit operatively connected to said recirculating switching means, whereby inductor current recirculation is enabled when required to prevent the voltage across said first load circuit from exceeding a predetermined value.

Claim 21

The invention as defined in claim 13 wherein said regulator regulates the generator output voltage at a predetermined maximum voltage in said second voltage range when the rotation rate of said generator is great enough for said maximum voltage to be achieved.

Claim 22

The invention as defined in claim 13 wherein said generator has a field winding of controllable energization, said regulator being coupled with said field winding, and wherein said field energization is provided by said generator and wherein said regulator includes means for limiting the fraction of the time that the generator is connected to the field winding in a manner dependent upon generator output voltage whereby maximum field current is limited.

Claim 23

The invention as defined in claim 13 including overvoltage protection means for preventing the voltage across said first load circuit from exceeding a predetermined value.