High Voltage Start of an Engine from a Low Voltage Battery

• US 20100283242A1
• Filed: 12/26/2007
• Published: 11/11/2010
• Est. Priority Date: 12/26/2007
• Status: Abandoned Application

• Current Assignee: Hamilton Sundstrand Corporation (Rtx Corporation), Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Inventors: Yee, Tony, Rozman, Gregory I., Dooley, Kevin A.
• Application Number:
  US11/964,129
• Publication Number:
  US 20100283242A1
• Time in Patent Office: Days
• US Class Current: 290/31
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 2011/0888 DC/DC converters
• CPC Class Codes: F02N 2011/0896 Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

Method and system are disclosed for starting a high voltage engine using a starter permanent magnet motor. The starter motor is powered using a DC power source remote from the starter motor. A bidirectional DC-to-DC converter local to the DC power source is used to produce a variable high voltage variable frequency power for driving the starter motor, and is remotely controlled to produce a controlled output current level. During generate mode the DC-DC converter may be used to charge the battery.

Claims

1. A system for producing variable high voltage variable frequency AC power to be used by a starter motor for starting an engine, the system comprising:

a DC power source for producing low voltage high current DC power, the DC power source being located remotely from the starter motor;

a DC-to-DC converter connected to the DC power source and located in an immediate vicinity of the DC power source, the DC-to-DC converter for converting the low voltage high current power to a variable high voltage low current DC power; and

a power converter for converting the high voltage low current DC power into the variable high voltage variable frequency AC power.

2. The system of claim 1, further comprising a current control unit for producing a current control signal, the producing being performed using a feedback signal indicative of the starter/generator phase currents, and wherein the converting of the low voltage high current power to a variable high voltage low current DC power is performed as a function of the current control signal.

3. The system of claim 1, wherein the DC-to-DC converter is mounted directly on the power source.

4. The system of claim 1, further comprising an electrical wire for electrically connecting the DC-to-DC converter and the power converter, the electrical wire of a gauge suitable for carrying high voltage low current DC power.

5. The system of claim 1, wherein the starter motor comprises an integrated starter generator (ISG) drivingly connected to the engine, the ISG for generating a high voltage AC power in a generator mode, the power converter being bidirectional and having a rectifying mode for rectifying the generated high voltage AC power to produce a high voltage low current DC power.

6. The system of claim 5, wherein the power source comprises a battery and wherein the DC-to-DC converter is bidirectional and, in the generator mode, is for using the generated high voltage low current DC power to produce low voltage variable DC current for charging the battery.

7. The system of claim 5, wherein the ISG comprises control windings, and the system further comprises a voltage regulation circuit for regulating the generated high voltage low current DC power, the voltage regulation circuit for producing a saturating control current for use by the control windings, the voltage regulation circuit being further for receiving a second feedback signal indicative of the DC high voltage and for varying the saturating control current in order to adjust the generated DC high voltage to a specified level.

8. The system of claim 5, wherein the high voltage AC drive current comprises a six-step constant-level drive current.

9. A system for producing variable high voltage variable frequency AC power to be used by a starter motor for starting an engine, the system comprising:

DC power means for producing low voltage high current DC power, the DC power means being located remotely from the starter motor;

DC-to-DC converter means connected to the DC power means and located in an immediate vicinity of the DC power means, the DC-to-DC converter means for converting the low voltage high current power to a variable high voltage low current DC power;

a power converter for converting the variable high voltage low current DC power into the variable high voltage variable frequency AC power.

10. A method for starting a high voltage engine, the method comprising:

providing a low voltage DC power source remote from the engine, the low voltage DC power producing a low voltage high current DC power;

converting the low voltage high current DC power to a variable high voltage low current DC power, in an area proximate the DC power source;

converting the variable high voltage low current DC power into a variable high voltage variable frequency AC drive power; and

starting the engine using the variable high voltage variable frequency AC power.

11. The method of claim 10, further comprising controlling a current level of the high voltage low current DC power as a function of a control current signal.

12. The method of claim 11 further comprising generating the current control signal using a first feedback signal indicative of the starter/generator phase currents.

13. The method of claim 10, further comprising, in a generator mode, generating a high AC voltage power supplied by the engine motive power and rectifying the AC voltage to produce a generated DC high voltage.

14. The method of claim 10, wherein the providing comprises providing a battery and further comprising, in the generator mode, charging the battery using the generated DC voltage conditioned by the DC-DC converter.