Power conversion system with stepped waveform inverter having prime mover start capability

• US 4,947,100 A
• Filed: 10/16/1989
• Issued: 08/07/1990
• Est. Priority Date: 10/16/1989
• Status: Expired due to Fees

• Current Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Dhyanchand, P. John, Nguyen, Vietson
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US07/421,830
• Time in Patent Office: 295 Days
• Field of Search: 363/37, 363/71, 363/72, 322/10, 322/11, 322/13, 322/32, 322/61, 290/31, 290/38 R, 290/46
• US Class Current: 322/10
• CPC Class Codes: F02N 11/04 the motors being associated with current generators

Abstract

A power conversion system is operable in a generating mode to convert motive power developed by a prime mover into electrical power and in a starting mode to convert electrical power developed by a source of AC power into motive power for starting the prime mover. The system includes a rectifier having an output coupled to a DC link, first and second inverters, each coupled to the DC link and transformer including first and second sets of primary windings and a set of secondary windings wherein the second set of primary winding is coupled to an output of the second inverter. Contactors are provided for coupling the rectifier to the generator armature windings and the first set of primary windings to an output of the first inverter so that AC power produced by the generator is converted into DC power on the DC link and the DC power is converted into fixed frequency AC power which is developed in the set of secondary windings. The contactors are operable in the starting mode to couple the source of AC power to the set of secondary windings, the first set of primary windings to the rectifier and the output of the first inverter to the generator armature windings so that the AC power induced in the first set of primary windings due to application of AC power to the set of secondary windings is converted into DC power on the DC link and the DC power is converted into AC power at a controlled voltage and frequency which is applied to the generator armature windings.

Claims

1. A power conversion system utilizing a generator having armature windings and coupled to a prime mover wherein the power conversion system is operable in a generating mode to convert motive power developed by the prime mover into electrical power and in a starting mode to convert electrical power developed by a source of AC power into motive power for starting the prime mover, comprising:

a rectifier having an output coupled to a DC link;

first and second inverters each coupled to the DC link;

a transformer including first and second sets of primary windings and a set of secondary windings wherein the second set of primary windings is coupled to an output of the second inverter;

means operable in the generating mode for coupling the rectifier to the generator armature windings and the first set of primary windings to an output of the first inverter and operable in the starting mode for coupling the source of AC power to the set of secondary windings, the first set of primary windings to the rectifier and the output of the first inverter to the generator armature windings; and

means for controlling the inverters in the generating mode to convert DC power on the DC link into fixed frequency AC power which is developed in the set of secondary windings and for controlling the first inverter in the starting mode whereby AC power induced in the first set of primary windings due to application of AC power to the set of secondary windings is converted into DC power on the DC link and the DC power is converted into AC power at a controlled frequency by the first inverter and is applied to the generator armature windings.

2. The power conversion system of claim 1, wherein the first set of primary windings are connected in a wye configuration.

3. The power conversion system of claim 1, wherein the second set of primary windings are connected in a delta configuration.

4. The power conversion system of claim 1, wherein the controlling means comprises a control unit which operates the inverters to produce a stepped AC waveform in the set of secondary windings in the generating mode.

5. A power conversion system utilizing a generator having armature windings and coupled to a prime mover wherein the power conversion system is operable in a generating mode to convert motive power developed by the prime mover into electrical power and in a starting mode to convert electrical power developed by a source of AC power into motive power for starting the prime mover, comprising:

a rectifier having an output coupled to a DC link;

first, second, third and fourth inverters each for converting DC power on the DC link into AC power;

a transformer including first, second, third and fourth sets of primary windings and a set of secondary windings wherein the second and fourth sets of primary windings are coupled to outputs of the second and fourth inverters, respectively; and

means operable in the generating mode for coupling the rectifier to the generator armature windings and the first and third sets of primary windings to outputs of the first and third inverters, respectively, so that AC power produced by the generator is converted into DC power on the DC link and the DC power is converted into fixed frequency AC power which is developed in the set of secondary windings and operable in the starting mode for coupling the source of AC power to the set of secondary windings, the first and third sets of primary windings to the rectifier and the outputs of the first and third inverters to the generator armature windings so that AC power induced in the first and third sets of primary windings due to application of AC power to the set of secondary windings is converted into DC power on the DC link and the DC power is converted into AC power at a controlled frequency and is applied to the generator armature windings.

6. The power conversion system of claim 5, wherein each of the first and third sets of primary windings includes windings connected in a wye configuration.

7. The power conversion system of claim 5, wherein each of the second and fourth sets of primary windings includes windings connected in a delta configuration.

8. The power conversion system of claim 5, further including means for operating the inverters to produce a 24-step AC waveform in the set of secondary windings in the generating mode.