Vehicle based AC power system

• US 5,656,922 A
• Filed: 12/14/1994
• Issued: 08/12/1997
• Est. Priority Date: 06/14/1993
• Status: Expired due to Fees

• Current Assignee: Ecoair Corp.
• Original Assignee: Ecoair Corp.
• Inventors: LaVelle, William J., Syverson, Charles D., Curtiss, William P.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/355,680
• Time in Patent Office: 972 Days
• Field of Search: 322/28, 322/29, 322/46
• US Class Current: 322/46
• CPC Class Codes: H02H 7/067 on occurrence of a load dump control on sudden change of load H02P9/10
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 7/163 with special means for initiating or limiting the excitation current
• CPC Class Codes: H02J 7/28 using magnetic devices with controllable degree of saturation in combination with controlled discharge tube or controlled semiconductor device
• CPC Class Codes: H02K 1/24 Rotor cores with salient poles ; Variable reluctance rotors
• CPC Class Codes: H02K 1/2713 the magnetisation axis of the magnets being axial, e.g. claw-pole type
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/2773 consisting of tangentially magnetized radial magnets
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 16/02 Machines with one stator and two or more rotors
• CPC Class Codes: H02K 19/103 Motors having windings on the stator and a variable reluctance soft-iron rotor without windings
• CPC Class Codes: H02K 19/36 Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches
• CPC Class Codes: H02K 19/365 with a voltage regulator
• CPC Class Codes: H02K 21/042 with permanent magnets and field winding both rotating
• CPC Class Codes: H02K 3/51 applicable to rotors only
• CPC Class Codes: H02K 9/02 : by ambient air flowing through the machine
• CPC Class Codes: H02K 9/06 : with fans or impellers driven by the machine shaft
• CPC Class Codes: H02P 2101/45 : for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 25/16 : characterised by the circuit arrangement or by the kind of wiring
• CPC Class Codes: H02P 9/305 : controlling voltage H02P9/302 takes precedence

Abstract

A vehicle based AC power system includes a specialized high efficiency vehicle alternator capable of supplying its maximum rated DC output current, even when being driven by an idling vehicle engine, to power a DC to AC inverter and provide maximum rated AC power at any engine speed. The alternator is preferably a wound field and permanent magnet hybrid alternator employing a three state bridge-type voltage regulator. An electrical load monitor electrically connected to monitor the electrical load on the alternator and a transmitter and receiver are used to remotely signal a user whenever there is an excessive load on the system.

Claims

1. A vehicle based AC power system comprising:

a vehicle engine installed in a vehicle for propelling the vehicle, the vehicle engine having an engine idling speed and an engine maximum speed;

a hybrid alternator having a maximum rated output current, the hybrid alternator being driven by the vehicle engine and including;

a stator having a stator winding and a stator winding output;

a rotor mounted for rotation within the stator, the rotor including;

a shaft mounted for rotation within the stator,

a wound field rotor portion mounted on the shaft for rotation within the stator, the wound field rotor portion having a rotor winding, and

a permanent magnet rotor portion mounted on the shaft for rotation within the stator, the permanent magnet rotor portion having at least one permanent magnet;

a voltage rectifier circuit connected to the stator winding output, the voltage rectifier circuit having a voltage rectifier output producing an output voltage for the hybrid alternator; and

a voltage regulator connected to the voltage rectifier output for regulating the output voltage of the hybrid alternator by switching a forward polarity voltage and a reverse polarity voltage to the rotor winding;

the alternator having the capability of producing the maximum rated output current when the vehicle engine is operating at the engine idling speed by switching the forward polarity voltage to the rotor winding; and

a DC to AC inverter having a DC input electrically connected to the hybrid alternator and an AC output for providing AC power to an AC power line.

2. A vehicle based AC power system according to claim 1 wherein:

the wound field rotor portion is mounted on the shaft for rotation within a first longitudinal region of the stator and includes a plurality of laminations arranged perpendicular to the shaft;

multiple electromagnetic poles are defined by a plurality of radially oriented projections from each lamination, one for each electromagnetic pole, the laminations being stacked together to form a salient pole rotor core and the rotor winding is wound around the stacked radial projections of the rotor core to form a plurality of coils around the rotor core, adjacent coils being wound in opposite directions to produce alternating north and south magnetic fields in adjacent electromagnetic poles when current is passed through the rotor winding, and

the permanent magnet rotor portion is mounted on the shaft in longitudinally spaced relation to the wound field rotor portion for rotation within a second longitudinal region of the stator, the permanent magnet rotor portion having multiple permanent magnetic poles defined by one or more permanent magnets, the number of permanent magnetic poles corresponding in number to the number of electromagnetic poles in the wound field rotor portion.

3. A vehicle based AC power system according to claim 2 wherein there are multiple permanent magnets in the permanent magnet rotor portion, one for each permanent magnetic pole.

4. A vehicle based AC power system according to claim 3 wherein each permanent magnet is mounted at the perimeter of the permanent magnet rotor portion and has a direction of magnetization that is oriented radially relative to the shaft.

5. A vehicle based AC power system according to claim 2 wherein the permanent magnetic poles in the permanent magnet rotor portion are produced by a multiple pole permanent magnet mounted with the direction of magnetization oriented parallel to the shaft.

6. A vehicle based AC power system according to claim 5 wherein the permanent magnet comprises a disk-shaped permanent magnet with the multiple poles magnetically formed therein.

7. A vehicle based AC power system according to claim 6 wherein the permanent magnet rotor portion further includes a flux channeling element formed of a magnetically permeable material, positioned longitudinally adjacent to the disk-shaped permanent magnet to channel magnetic flux to the air gap between the stator and the rotor.

8. A vehicle based AC power system according to claim 2 wherein the permanent magnetic poles in the permanent magnet rotor portion are produced by a plurality of permanent magnets arranged in circumferentially spaced relation around the shaft with the direction of magnetization oriented circumferentially relative to the shaft.

9. A vehicle based AC power system according to claim 8 wherein the permanent magnet rotor portion further includes a plurality of flux channeling elements, formed of a magnetically permeable material and positioned circumferentially adjacent to and between the circumferentially spaced permanent magnets.

10. A vehicle based AC power system according to claim 1 further comprising:

an electrical load monitor electrically connected to monitor the electrical load on the alternator, the electrical load monitor producing an output signal indicative of the load on the alternator; and

an indicating device responsive to the output signal from the electrical load monitor for indicating an excessive load on the alternator.

11. A vehicle based AC power system according to claim 1 wherein the engine has an engine idling speed which is less than 1500 rotations per minute.

14. A vehicle based AC power system according to claim 10 wherein the indicating device includes a warning indicator mounted in the vehicle.

15. A vehicle based AC power system according to claim 10 wherein the indicating device comprises a transmitter which transmits a warning signal to a remotely located receiver.

16. A vehicle based AC power system according to claim 15 wherein the transmitter is a radio transmitter.

17. A vehicle based AC power system according to claim 15 wherein the transmitter is connected to the AC power line to transmit an encoded signal on the AC power line to the remotely located receiver, the remotely located receiver being connected to the AC power line to receive the encoded signal.

12. A vehicle based AC power system comprising:

a vehicle engine installed in a vehicle for propelling the vehicle, the vehicle engine having an engine idling speed and an engine maximum speed;

a high efficiency hybrid alternator including one or more permanent magnets used in combination with a winding to produce a DC output current at a DC output, the alternator being driven by the vehicle engine and having a maximum rated output current, the alternator having the capability of producing the maximum rated output current at the DC output of the alternator when the vehicle engine is operating at the engine idling speed and when the vehicle engine is operating at the engine maximum speed; and

a voltage regulator for controlling bidirectional current flow through the winding of the alternator, 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 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; and

a DC to AC inverter having a DC input electrically connected to the DC output of the alternator and having an AC output for providing AC power to an AC power line.

13. A vehicle based AC power system according to claim 12 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.