Power conversion system having prime mover start capability

• US 5,013,929 A
• Filed: 11/22/1989
• Issued: 05/07/1991
• Est. Priority Date: 11/22/1989
• Status: Expired due to Term

• Current Assignee: Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Sundstrand Corporation (Rtx Corporation)
• Inventors: Dhyanchand, P. John
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US07/440,273
• Time in Patent Office: 531 Days
• Field of Search: 290/10, 290/22, 290/31, 290/46, 322/10, 322/29
• US Class Current: 290/31
• CPC Class Codes: F02N 11/04 the motors being associated with current generators

Abstract

A power conversion system utilizes a brushless generator driven by a prime mover when operating in a generating mode and drives the prime mover when operating in a starting mode. The system includes an AC/DC power rectifier and an inverter coupled to the AC/DC power rectifier for developing at least one AC voltage. Contactors are provided for coupling, when in the generating mode, the generator to the rectifier input and the inverter output to an AC load during operation in the generating mode, and for coupling an external power source to the rectifier input and the inverter output to the generator during operation in the starting mode. Transformers are provided for adjusting system voltages so that the generator windings need not be modified to accomplish starting of the prime mover.

Claims

1. A power conversion system operable in a generating mode to convert motive power into electrical power and in a starting mode to convert electrical power into motive power utilizing an external power source and a generator having armature windings, comprising:

an AC/DC power rectifier;

a DC/AC inverter;

a DC link coupling said rectifier with said inverter;

said rectifier having an input and said inverter having an output;

a first transformer and a second transformer;

first means operable when in said generating mode to couple the armature windings to said first transformer and operable when in said starting mode to couple the armature windings to said output;

said first means further being operable when in said generating mode to couple said first transformer to said input;

said first means still further being operable when in said generating mode to couple said output to said second transformer; and

second means operable when in said generating mode to couple said second transformer to an AC load and when in said starting mode to couple said second transformer to the external power source.

2. The power conversion system of claim 1, wherein said first and second transformers are autotransformers.

3. The power conversion system of claim 1, wherein said first means comprises first contactors connected to said windings and connectable to either said first transformer or said output, second contractors connected to said first transformer and connectable to said input, and third contactors connected to said second transformer and connectable to either said output or said input.

4. The, power conversion system of claim 1, further including a control unit to said motive power for controlling said first means.

5. A power conversion system operable in a generating mode to convert motive power into electrical power and in a starting mode to convert electrical power into motive power utilizing an external power source and a generator having armature windings, comprising:

an AC/DC power rectifier having an input and an output;

a DC/AC inverter having an input coupled to said output of said rectifier;

first means operable during operation in the generating mode for connecting said input of said AC/DC power rectifier to the generator armature windings whereby AC power developed by the generator in response to the application of motive power thereto is converted into AC power on said output of said inverter;

control means coupled to said inverter for operating same while in the generating mode so that said inverter produces substantially constant frequency AC power for an AC load;

second means operable in said generating mode for connecting said output of said inverter to an AC load;

said first and second means further being operable in said starting mode to couple the external power source to said input of said rectifier and said output of said inverter to said armature windings whereby said inverter provides AC power to the generator armature windings and causes same to operate as a motor; and

a first autotransformer coupled between said first means and said AC/DC rectifier while in said generating mode.

6. The power conversion system of claim 5, and further including third means coupling said first autotransformer with said rectifier while in said generating mode and uncoupling said first autotransformer from said converter while in said starting mode.

7. The power conversion system of claim 5, and further including a second autotransformer coupled between said second means and the AC load while in the generating mode.

8. The power conversion system of claim 5, and further including control means connected to said first and second means for changing operation between said generating and starting modes.

9. The power conversion system of claim 6, and further including control means connected to said first, second and third means for changing operation between said generating and starting modes.