Hybrid alternator with voltage regulator

Claim 2

A voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, the voltage regulator comprising: a voltage monitoring circuit connected to monitor the output voltage of the alternator, the voltage monitoring circuit producing an error signal indicating that the output voltage of the alternator should be increased or decreased; a switching circuit connected to the winding and arranged to connect the winding in multiple modes, including: a forward polarity mode in which a forward polarity voltage is applied to the winding, a reverse polarity mode in which a reverse polarity voltage is applied to the winding, and a decay mode in which current induced in the winding when connected in the forward or reverse polarity mode is permitted to decay without inducing damaging voltages in the voltage regulator; and a control circuit connected to the switching circuit, responsive to the error signal of the monitoring circuit, the control circuit controlling the switching circuit to enter the forward polarity mode to increase the output voltage of the alternator, to enter the reverse polarity mode to decrease the output voltage of the alternator and to enter the decay mode whenever switching away from the forward or reverse polarity mode.

Claim 3

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 wherein the switching circuit comprises a bridge circuit including: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the control circuit controlling the switching circuit to enter the forward polarity mode by closing the first pair of switches; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the control circuit controlling the switching circuit to enter the reverse polarity mode by closing the second pair of switches; and the control circuit controlling the switching circuit to enter the decay mode by closing the first and second upper switches or by closing the first and second lower switches.

Claim 4

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 2 wherein the control circuit controls the switching circuit to enter the decay mode by closing the first and second upper switches.

Claim 5

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 wherein the decay mode comprises: a forward decay mode in which current induced in the winding during the forward polarity mode decays; and a reverse decay mode in which current induced in the winding during the reverse polarity mode decays; and wherein the control circuit controls the switching circuit to enter the forward decay mode when switching away from the forward polarity mode and to enter the reverse decay mode when switching away from the reverse polarity mode.

Claim 6

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 4 wherein: the switching circuit comprises a bridge circuit including: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the control circuit controlling the switching circuit to enter the forward polarity mode by closing the first pair of switches; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the control circuit controlling the switching circuit to enter the reverse polarity mode by closing the second pair of switches; the control circuit controlling the switching circuit to leave the forward polarity mode and enter the forward decay mode by opening the first upper switch and leaving the first lower switch closed; and the control circuit controlling the switching circuit to leave the reverse polarity mode and enter the reverse decay mode by opening the second upper switch and leaving the second lower switch closed.

Claim 7

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 5 wherein the first and second lower switches of the bridge circuit have the property that they conduct current in one direction only when closed, but conduct current in the opposite direction when open and when closed, the second lower switch being closed and conducting current when the switching circuit is in the forward decay mode and the first lower switch being closed and conducting current when the switching circuit is in the reverse decay mode.

Claim 8

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 6 wherein the first and second lower switches of the bridge circuit are field effect transistors.

Claim 9

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 wherein the control circuit further includes a decay current detecting circuit connected to detect the existence of forward and reverse polarity induced current in the winding when the switching circuit is in the decay mode, the decay current detecting circuit producing an inhibiting signal preventing the switching circuit from entering the forward polarity mode when a substantial reverse polarity induced current is in the winding and preventing the switching circuit from entering the reverse polarity mode when a substantial forward polarity induced current is in the winding.

Claim 10

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 8 wherein the switching circuit includes a plurality of semiconductor switches connected to the winding, the decay current detecting circuit detecting the existence of forward and reverse polarity induced current in the winding by detecting a voltage drop across at least one of said semiconductor switches.

Claim 11

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 further comprising a transient suppression circuit connected to the switching circuit to absorb a transient voltage spike in the output voltage of the alternator having a voltage in excess of a predetermined voltage.

Claim 12

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 10 wherein: the switching circuit includes: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the first pair of switches defining the forward polarity mode in which a forward polarity voltage is applied to the winding when the first pair of switches are closed; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the second pair of switches defining the reverse polarity mode in which a reverse polarity voltage is applied to the winding when the second pair of switches are closed; and the transient suppression circuit is connected to the switching circuit to switch on an upper switch from one of the first and second pairs of switches and a lower switch from the other of the first and second pairs of switches to absorb the transient voltage spike.

Claim 13

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 11 wherein the transient suppression circuit switches on the upper switch and the lower switch from each of the first and second pairs of switches to absorb the transient voltage spike.

Claim 14

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 11 wherein the transient suppression circuit includes: a zener diode connected to detect the transient voltage spike; and a plurality of directing diodes connected to the zener diode and to the switches to turn on the switches when a transient voltage spike is detected.

Claim 15

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 13 wherein the plurality of directing diodes comprise a corresponding directing diode for each switch in the switching circuit, and the transient suppression circuit switches on the upper switch and the lower switch from each of the first and second pairs of switches.

Claim 16

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 further comprising: an internal power supply circuit automatically producing an internal power supply output voltage whenever the alternator rotates; and the control circuit is connected to and automatically powered by the internal power supply circuit when the alternator begins to rotate to control current flow through the winding of the alternator, and automatically unpowered when the alternator ceases rotation to discontinue current flow through the winding of the alternator.

Claim 17

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 15 wherein the internal power supply circuit includes: a voltage rectifier circuit, producing a rectified internal power supply output voltage; and an internal power supply voltage regulating circuit connected to the voltage rectifier circuit for regulating the rectified internal power supply output voltage; the voltage regulator being powered by the regulated internal power supply output voltage.

Claim 18

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 adapted to be installed in a vehicle with an ignition switch having an off position wherein the control circuit supplies reverse current flow through the winding of the alternator to maintain a safe alternator output voltage if the ignition switch is switched to the off position with the alternator rotating at a high speed.

Claim 19

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 17 wherein the control circuit is not powered through the ignition switch of the vehicle.

Claim 20

A voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, the voltage regulator comprising: means for connecting the winding in a forward polarity mode to apply a forward polarity voltage to the winding and increase the output voltage of the alternator; means for connecting the winding in a reverse polarity mode to apply a reverse polarity voltage to the winding and decrease the output voltage of the alternator; means for connecting the winding in a decay mode to allow current induced in the winding when connected in the forward or reverse polarity mode to decay.

Claim 21

A voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, the voltage regulator comprising: means for connecting the winding in a forward polarity mode to apply a forward polarity voltage to the winding and increase the output voltage of the alternator; means for connecting the winding in a reverse polarity mode to apply a reverse polarity voltage to the winding and decrease the output voltage of the alternator; means for connecting the winding in a decay mode to allow current induced in the winding when connected in the forward or reverse polarity mode to decay.

Claim 22

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 1 wherein: the voltage monitoring circuit includes: a reference voltage source, and a comparator connected to the output voltage of the alternator and the reference voltage source, the comparator producing the error signal indicating that the output voltage of the alternator should be increased or decreased; the switching circuit includes a plurality of semiconductor switches arranged in a bridge configuration connected to the winding, the semiconductor switches including: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the first pair of switches defining the forward polarity mode in which a forward polarity voltage is applied to the winding when the first pair of switches are closed; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the second pair of switches defining the reverse polarity mode in which a reverse polarity voltage is applied to the winding when the second pair of switches are closed; the switches defining the decay mode in which current induced in the winding when connected in the forward or reverse polarity mode is permitted to decay when both of the upper switches or both of the lower switches are open; and the control circuit for controlling the switches of the switching circuit includes: a primary circuit connected to the voltage monitoring circuit, the primary circuit producing primary control signals to increase or decrease the output voltage of the alternator responsive to the error signal of the monitoring circuit, a decay current detecting circuit producing an inhibiting signal when the switching circuit is in the decay mode and current is decaying in the winding, and a logic circuit, responsive to the primary control signals and the inhibiting signal, connected to the switching circuit, the logic circuit producing secondary control signals for switching the switching circuit between the forward and reverse polarity modes and the decay mode.

Claim 23

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 20 wherein the primary circuit produces digital primary control signals including: an undelayed primary control signal, and a delayed primary control signal.

Claim 24

A voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, to the voltage regulator comprising: a voltage monitoring circuit connected to monitor an output voltage of the alternator, the voltage monitoring circuit producing an error signal indicating that the output voltage of the alternator should be increased or decreased; a switching circuit including a plurality of switches arranged in a bridge configuration connected to the winding to conduct current through the winding in a forward direction in forward polarity mode to increase the output voltage of the alternator and to conduct current in a reverse direction through the winding in a reverse polarity mode to decrease the output voltage of the alternator the switching circuit including: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the first pair of switches defining the forward polarity mode in which a forward polarity voltage is applied to the winding when the first pair of switches are closed; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the second pair of switches defining the reverse polarity mode in which a reverse polarity voltage is applied to the winding when the second pair of switches are closed; a control circuit connected to the switching circuit to the switch alternator between the forward polarity and reverse polarity modes in response to the error signal; and a transient suppression circuit connected to the switching circuit to switch on an upper switch from one of the first and second pairs of switches and a lower switch from the other of the first and second pairs of switches to absorb a transient voltage spike in the output voltage of the alternator having a voltage in excess of a predetermined voltage.

Claim 25

A voltage regulator for controlling bidirectional current flow through a winding of an alternator to control an output voltage of the alternator, to the voltage regulator comprising: a voltage monitoring circuit connected to monitor an output voltage of the alternator, the voltage monitoring circuit producing an error signal indicating that the output voltage of the alternator should be increased or decreased; a switching circuit including a plurality of switches arranged in a bridge configuration connected to the winding to conduct current through the winding in a forward direction in forward polarity mode to increase the output voltage of the alternator and to conduct current in a reverse direction through the winding in a reverse polarity mode to decrease the output voltage of the alternator the switching circuit including: a first upper switch connected to a first end of the winding; a first lower switch connected to a second end of the winding, the first lower switch forming with the first upper switch a first pair of switches, the first pair of switches defining the forward polarity mode in which a forward polarity voltage is applied to the winding when the first pair of switches are closed; a second upper switch connected to the second end of the winding; and a second lower switch connected to the first end of the winding, the second lower switch forming with the second upper switch a second pair of switches, the second pair of switches defining the reverse polarity mode in which a reverse polarity voltage is applied to the winding when the second pair of switches are closed; a control circuit connected to the switching circuit to the switch alternator between the forward polarity and reverse polarity modes in response to the error signal; and a transient suppression circuit connected to the switching circuit to switch on an upper switch from one of the first and second pairs of switches and a lower switch from the other of the first and second pairs of switches to absorb a transient voltage spike in the output voltage of the alternator having a voltage in excess of a predetermined voltage.

Claim 26

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 22 wherein the transient suppression circuit switches on the upper switch and the lower switch from each of the first and second pairs of switches to absorb the transient voltage spike.

Claim 27

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 22 wherein the transient suppression circuit includes: a zener diode connected to detect the transient voltage spike; and a plurality of directing diodes connected to the zener diode and to the switches to turn on the switches when a transient voltage spike is detected.

Claim 28

A voltage regulator for controlling bidirectional current flow through a winding of an alternator according to claim 24 wherein the plurality of directing diodes comprise a corresponding directing diode for each switch in the switching circuit, and the transient suppression circuit switches on the upper switch and the lower switch from each of the first and second pairs of switches to absorb the transient voltage spike in all of the switches in the switching circuit.

Claim 31

A method of controlling bidirectional current flow through a winding of an alternator according to claim 26 further including the steps of: monitoring the recirculating current flow through the winding during the decay mode to produce an inhibiting signal when recirculating current is flowing; and controlling the switching of the winding responsive to the inhibiting signal.

Claim 32

A method of controlling bidirectional current flow through a winding of an alternator according to claim 27 wherein: the step of monitoring the recirculating current flow through the winding during the decay mode includes the step of monitoring the direction of recirculating current flow through the winding; and the step of controlling the switching of the winding includes controlling the switching of the winding to prevent entering the reverse polarity mode when recirculating forward direction current is flowing and controlling the switching of the winding to prevent entering the forward mode when recirculating reverse direction current is flowing.