IP Library › Granted Patent US 7,514,807

Granted Patent B2

US 7,514,807 · App. 11/411,987 · Granted Apr 7, 2009

Alternator boost method

Assignee: Railpower Technologies Corp.

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Quick Facts

Patent No.: US 7,514,807
App. No.: 11/411,987
Granted: Apr 7, 2009
Kind: B2

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Abstract

A circuit for boosting the voltage output of an alternator utilizes the armature coils of the alternator as part of the boost circuit. The circuit and methods utilizing this circuit can enable refined control strategies for operating a plurality of engine systems during propulsion, idling and braking and is applicable to large systems such as trucks, ships, cranes and locomotives utilizing diesel engines, gas turbine engines, other types of internal combustion engines, fuel cells or combinations of these that require substantial power and low emissions utilizing multiple power plant combinations.

Claims (60)

1. A propulsion system, comprising:

(a) an engine system comprising:

an engine; and

an n-phase alternator operable to convert mechanical energy output by the engine into alternating current electrical energy, each phase corresponding to an armature winding;

(b) at least one traction motor in electrical communication with the alternator;

(c) a plurality of pairs of first and second rectifier diodes to convert the outputted alternating current electrical energy into direct current electrical energy, each of said plurality of pairs of rectifier diodes being connected to a respective n-armature winding of the alternator, each of said first and second rectifier diodes having an input and an output, the output of the first rectifier diode being connected to the input of the second rectifier diode and to the respective n-armature winding of the alternator; and

(d) a voltage boost circuit electrically connected with each of the n-armature windings of the alternator to boost an output voltage associated with each armature winding, wherein each armature winding provides an inductance for the voltage boost circuit, the voltage boost circuit comprising:

a single switch having an input and an output, the output of the switch being connected to the inputs of the plurality of first rectifier diodes;

a plurality of power diodes connected in parallel to the switch, each of said plurality of power diodes having an input and an output, the input of each of said plurality of power diodes being connected to a respective output of the first rectifier diode of the plurality of pairs of rectifier diodes, the output of each of said plurality of power diodes being connected in parallel to input of the switch; and

a capacitor connected in parallel to the plurality of pairs of first and second rectifier diodes.

2. The propulsion system of claim 1 , wherein the single switch is an IGBT switch and further comprising: a control system operable, based on a measured mechanical or electrical parameter of the alternator, to control a switching rate of the IGBT switch such that the IGBT switch, the capacitor, and the diodes form a variable voltage boost circuit with each of the n-armature windings of the alternator during the corresponding power phase of the nth armature winding, whereby the output voltage of the engine system can be varied independently of engine speed.

3. The system of claim 1 , wherein the switch, in a first mode, is conducting and, in a second mode, is nonconducting and rectifies the electrical energy.

4. The system of claim 1 , wherein the voltage boost circuit does not boost the voltage when a revolutions-per-minute of the engine is greater than a first threshold and boosts the voltage when the revolutions-per-minute of the engine is less than the first threshold.

5. A propulsion method, comprising the steps of:

(a) providing a propulsion system, comprising:

(i) an engine system comprising:

an engine; and

an n-phase alternator operable to convert mechanical energy output by the engine into alternating current electrical energy, each phase corresponding to an armature winding;

(ii) at least one traction motor in electrical communication with the alternator;

(iii) a plurality of pairs of first and second rectifier diodes to convert the outputted alternating current electrical energy into direct current electrical energy, each of said plurality of pairs of rectifier diodes being connected to a respective n-armature winding of the alternator, each of said first and second rectifier diodes having an input and an output, the output of the first rectifier diode being connected to the input of the second rectifier diode and to the respective n-armature winding of the alternator; and

(iv) a voltage boost circuit electrically connected with each of the n-armature windings of the alternator to boost an output voltage associated with each armature winding, wherein each armature winding provides an inductance for the voltage boost circuit, the voltage boost circuit comprising:

a single switch having an input and an output, the output of the switch being connected to the inputs of the plurality of first rectifier diodes;

a capacitor connected in parallel to the plurality of pairs of first and second rectifier diodes;

(b) in a first mode in which the switch is conducting, directing the outputted electrical current of the n-phase alternator along a first path through the power diodes, through the switch, and back to a selected one of the armature windings of the alternator, thereby storing electrical energy in the selected armature winding; and

(c) in a second mode in which the switch is nonconducting, directing the output electrical current along a second path through the rectifier diodes to a load, wherein the second path bypasses the switch.

6. The method of claim 5 , wherein each armature winding is in the first mode at a different time, wherein a control system, based on a measured mechanical or electrical parameter of the alternator, controls the on-off duty cycle of the switch between the first and second modes such that the switch, the capacitor, and the power diodes form a variable voltage boost circuit with each of the n-armature windings of the alternator during the corresponding first mode of the nth armature winding, whereby the output voltage of the engine system can be varied independently of engine speed.

7. The method of claim 5 , wherein in the first mode the current flows through the capacitor in a first direction and in the second mode the current flows through the capacitor in an opposing second direction.

8. In a multi-engine vehicle, a propulsion method, comprising the steps of:

(a) determining an operating voltage range for a direct current electrical bus;

(b) determining a power requirement to be provided to the direct current electrical bus by a plurality of engines;

(c) selecting at least a subset of the engines systems to provide the determined power requirement to the direct current electrical bus;

(d) determining a first magnitude of an operational parameter for each of the selected engine systems to provide, to the direct current electrical bus, the selected engine's portion of the determined power requirement;

(e) setting each of the selected engine systems to the corresponding first magnitude of the determined operational parameter to provide the selected engine system's portion of the determined power requirement to the direct current electrical bus;

(f) measuring an electrical parameter of each of the selected engine systems;

(g) comparing the measured electrical parameter of each of the selected engine systems to the corresponding portion of the determined power requirement; and

(h) if needed, adjusting at least one of (i) the first magnitude of the operational parameter of the selected engine system and (ii) the electrical parameter of the selected engine system to produce the corresponding required electrical power output for the selected engine system,

wherein at least one of the selected engine systems comprises:

(i) an n-phase alternator operable to convert mechanical energy output by the engine system into alternating current electrical energy, each phase corresponding to an armature winding;

(ii) at least one traction motor in electrical communication with the alternator;

a single switch having an input and an output, the output of the switch being connected to the inputs of the plurality of first rectifier diodes;

a capacitor connected in parallel to the plurality of pairs of first and second rectifier diodes.

9. The method of claim 8 , wherein in the setting step (e), the electrical parameter is set and wherein the electrical parameter is at least one of an output electrical voltage, an output electrical current and output electrical power.

10. A propulsion system, comprising:

(a) a plurality of prime power systems, each prime power system comprising; a prime power source device; and an energy conversion device operable to convert energy output by the prime power device into direct current electrical energy, wherein the prime power system is an engine and the energy conversion device is a mechanical-to-electrical energy conversion device operable to convert mechanical energy output by the engine into direct current electrical energy;

(b) a direct current bus connecting the plurality of prime power systems, the direct current bus being operable to carry the direct current electrical energy to and/or from the prime power systems;

(d) a plurality of current sensors, each current sensor measuring a direct current electrical energy outputted by a selected prime power system; and

(e) a control system operable, based on the measured voltage level across the direct current bus and the respective measured direct current electrical energy into and/or out of each prime power system, to control an electrical parameter of the selected prime power system, wherein the electrical parameter is at least one of an output electrical voltage, an output electrical current, and output electrical power; and

wherein the selected prime power system comprises:

(i) an n-phase alternator operable to convert mechanical energy output by the selected prime power system into alternating current electrical energy, each phase corresponding to an armature winding;

(ii) at least one traction motor in electrical communication with the alternator;

a single switch having an input and an output, the output of the switch being connected to the inputs of the plurality of first rectifier diodes;

a capacitor connected in parallel to the plurality of pairs of first and second rectifier diodes.

Assignments (2)

ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 24, 2009

From: RAILPOWER TECHNOLOGIES CORP.; RAILPOWER HYBRID TECHNOLOGIES CORP.

To: RAILPOWER, LLC

Reel/Frame 022990/0962 →

ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 1, 2006

From: DONNELLY, MR. FRANK; TARNOW, MR. ANDREW

To: RAILPOWER TECHNOLOGIES CORPORATION

Reel/Frame 018041/0269 →

Continuity (4)

Provisional Application 6067483700 · Apr 25, 2005

Provisional Application 6069240000 · Jun 20, 2005

Provisional Application 6075344400 · Dec 22, 2005

Related Publication 20060266044A1 · Nov 30, 2006