Transformerless, load adaptive speed controller

• US 6,879,053 B1
• Filed: 10/22/2003
• Issued: 04/12/2005
• Est. Priority Date: 10/22/2002
• Status: Expired due to Fees

• Current Assignee: The Switch Controls and Converters, Inc. (Yaskawa Electric Corporation)
• Original Assignee: Youtility Incorporated
• Inventors: Wen, Jian, Welches, Richard Shaun, Griessel, Richard, O'Reilly, Thomas, Hohm, Daniel P., LeRow, Kevin E
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): Mohandesi, Iraj A.
• Application Number:
  US10/691,030
• Time in Patent Office: 538 Days
• Field of Search: 290/6, 290/1.A, 290/4.R, 290/31, 290/32, 290/30.R, 290/36, 290/38.R, 322/24, 322/10, 322/12, 322/13, 322/20
• US Class Current: 290/6
• CPC Class Codes: H02J 3/00125 Transmission line or load transient problems, e.g. overvoltage, resonance or self-excitation of inductive loads H02J3/01 takes precedence
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02J 3/1864 wherein the stepless control of reactive power is obtained by at least one reactive element connected in series with a semiconductor switch
• CPC Class Codes: H02J 3/30 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence
• CPC Class Codes: Y02E 40/40 Arrangements for reducing harmonics
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

The invention in the simplest form is an improved variable speed engine/generator set with an integrated power conditioning system and control method, used to generate high quality AC power with optimum fuel efficiency and reduced emissions. The variable speed generator control scheme allows for load adaptive speed control of engine and generator field. The transformerless power inverter topology and control method provides the necessary output frequency, voltage and/or current waveform regulation, harmonic distortion rejection, and provides for single phase, or unbalanced loading.

Claims

1. An apparatus for generating AC power to a load, comprising:

a variable speed energy generating device producing differing amounts of power at different speeds;

a power conditioning system coupled to said variable speed energy generating device, wherein said power conditioning system calculates a speed command based on said AC power that controls said variable speed energy generating device;

a regulator section coupled to said power conditioning system;

a converter coupled to said regulator section and producing said AC power, wherein said converter couples said AC power to said load a speed sensor coupled to said variable speed energy generating device and an adaptive speed loop gain algorithm for detecting steady state speed errors.

2. The apparatus according to claim 1, wherein said converter is selected from the group consisting of:

transformerless AC pulse width modulator inverter, DC-AC inverter, static inverter, rotary converter, cycloconverter, and AC-AC motor generator set.

3. The apparatus according to claim 1, wherein the variable speed energy generating device is selected from the group consisting of:

internal combustion engine, turbine, micro-turbine and Stirling engine.

4. The apparatus according to claim 1, wherein said regulator section is an enhanced conduction angle dual boost DC bus voltage regulator.

5. The apparatus according to claim 1, further comprising a field winding coupled to said variable speed energy generating device.

6. The apparatus according to claim 1, wherein said speed command is derived from engine speed versus load lookup tables.

7. The apparatus according to claim 1, wherein said speed command is calculated from exhaust content sensors.

8. The apparatus according to claim 1, further comprising a bypass switch coupling said variable speed energy generating device to said load.