Stepped waveform VSCF system with engine start capability

• US 5,387,859 A
• Filed: 03/25/1993
• Issued: 02/07/1995
• Est. Priority Date: 03/25/1993
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Widdis, James, Eckenfelder, Robert C., Murugan, Muthu K.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US08/036,793
• Time in Patent Office: 684 Days
• Field of Search: 322/10
• US Class Current: 322/10
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02M 7/49 Combination of the output voltage waveforms of a plurality of converters

Abstract

A power converter that can be used either as a start converter or as a variabe speed constant frequency converter is utilized within a stepped waveform VSCF system having engine start capability. Interfacing with the converter are a load bus, a contactor, a field excitation controller and a starter/generator having a main generator, an exciter generator and a permanent magnet generator. Magnetic components and semiconductor components perform multi-functions and minimal degradation of input power quality occurs.

Claims

1. A stepped waveform VSCF system with engine start capability comprising:

starter/generator means mounted to an engine;

converter means connected to said starter/generator means and including a plurality of DC/AC inverters connected to said starter/generator means, a plurality of high frequency trap-tuned filters connected to contactor means, three phase transformer means connected between said plurality of high frequency trap-tuned filters and said plurality of DC/AC inverters for providing isolation, and filter capacitor means connected across said plurality of DC/AC inverters;

field excitation controller means connected to said starter/generator means;

control power supply means connected to said field excitation controller means;

said contactor means connected to said converter means;

load bus means connected to said contactor means;

said three phase transformer means including secondary winding means connected to said plurality of high frequency trap-tuned filters and primary winding means connected to said plurality of DC/AC inverters;

said converter means including timing logic means for switching on and off at a desired frequency, each of a plurality of semiconductor switches to produce a multiple step three-phase output voltage at said secondary winding means of said three phase transformer means;

said converter means further including PWM controller means connected to said control power supply means;

resolver means connected between said starter/generator means and said PWM controller means; and

back EMF sensor circuit means connected to said PWM controller means.

2. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein said starter/generator means comprises:

permanent magnet generator means connected to said engine;

exciter generator means connected to said permanent magnet generator means and to said field excitation controller means; and

,

main generator means connected to said exciter generator means and to said converter means.

3. A stepped waveform VSCF system with engine start capability as claimed in claim 2 wherein said permanent magnet generator means provides power to said field excitation controller means which influences excitation of exciter of said exciter generator means within said starter/generator means.

4. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein each of said plurality of DC/AC inverters comprises:

a plurality of semiconductor switches having associated flywheel rectifiers or diodes.

5. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein said converter means can be used as a start converter.

6. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein said converter means can be used as a variable speed constant frequency converter.

7. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein said converter means can be used as a start converter and as a variable speed constant frequency converter causing minimal degradation of input power quality.

8. A stepped waveform VSCF system with engine start capability as claimed in claim 1 wherein said converter means comprises:

five DC/AC three-phase inverters connected to said starter/generator means;

three high frequency trap-tuned filters connected to said contactor means;

three phase transformer means connected between said three high frequency trap-tuned filters and said five DC/AC converters for providing isolation; and

,

filter capacitor means connected across said five DC/AC converters.

9. A stepped waveform VSCF system with engine start capability as claimed in claim 8 wherein each of said five DC/AC inverters comprises:

six semiconductor switches having associated flywheel rectifiers or diodes.

10. A stepped waveform VSCF system with engine start capability as claimed in claim 9 wherein said three phase transformer means comprises:

said secondary winding means connected to said three high frequency trap-tuned filters; and

,

said primary winding means connected to four of said five DC/AC inverters.

11. A stepped waveform VSCF system with engine start capability as claimed in claim 10 wherein said converter means further comprises:

said timing logic means for switching on and off at the desired frequency, each of said six semiconductor switches to produce a twenty-four step three-phase AC output voltage at said secondary winding means of said three-phase transformer means.