Energy storage flywheel voltage regulation and load sharing system and method

• US 7,078,880 B2
• Filed: 08/15/2003
• Issued: 07/18/2006
• Est. Priority Date: 08/15/2003
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Abel, Stephen G., Potter, Calvin C., Klupar, George J.
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): Cuevas, Pedro J.
• Application Number:
  US10/641,509
• Publication Number:
  US 20050035744A1
• Time in Patent Office: 1,068 Days
• Field of Search: 322/4, 322/59, 244/165, 318/768, 318/771
• US Class Current: 322/4
• CPC Class Codes: H02J 3/30 using dynamo-electric machines coupled to flywheels
• CPC Class Codes: H02K 7/025 for power storage
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A system for regulating the voltage in an electrical distribution system includes a plurality of flywheels, motor/generators, and controllers. Each of the motor/generators is coupled to one of the energy storage flywheels and to the electrical supply system. The motor/generators each supply one or more signals representative of motor/generator operational parameters, and each motor/generator controllers receive one or more of the motor/generator operational parameter signals from each of the motor/generators. In response to the operational parameter signals, the motor/generator controllers each control the operation of one of the motor/generators in either a motor mode or a generate mode, to thereby regulate the electrical supply system voltage and equally share the electrical load between the motor/generators.

Claims

1. A system for regulating voltage in an electrical supply system, comprising:

a plurality of energy storage flywheels;

a plurality of motor/generators, each motor/generator coupled to one of the energy storage flywheels and to the electrical supply system and configured to operate in either (i) a motor mode, whereby electrical energy from the electrical supply system is converted to rotational kinetic energy and supplied to its respective energy storage flywheel or (ii) a generate mode, whereby rotational kinetic energy from its respective energy storage flywheel is converted to electrical energy and supplied to the electrical supply system, each motor/generator further configured to supply a plurality of signals, each signal representative of a motor/generator operational parameter; and

a plurality of motor/generator controllers, each motor/generator controller coupled to receive a plurality of the motor/generator operational parameter signals from each of the motor/generators and operable, in response thereto, to control operation of one of the motor/generators in either the motor mode or the generate mode, to thereby regulate the electrical supply system voltage and substantially equally share electrical load between the motor/generators.

2. The system of claim 1, wherein each motor/generator controller is further operable, in response to the motor/generator operational parameter signals, to configure one of the motor/generators to operate in either the motor mode or the generate mode.

3. The system of claim 2, wherein the motor/generator operational parameter signals supplied by each motor/generator include a motor/generator rotational speed signal, and wherein each motor/generator controller comprises:

a speed comparator circuit coupled to receive the rotational speed signal from each motor/generator and operable, in response thereto, to supply a speed error signal;

a control filter circuit coupled to receive the speed error signal and operable, in response thereto, to supply operational control signals; and

a control logic circuit coupled to receive the operational control signals and operable, in response thereto, to control the operation of one of the motor/generators.

4. The system of claim 3, wherein the motor/generator operational parameter signals supplied by each motor/generator further include a motor/generator current signal, and wherein each motor/generator controller further comprises:

a current trim circuit coupled to receive the motor/generator current signal from one or more of the motor/generators and operable, in response thereto, to supply a trimmed current signal.

5. The system of claim 4, wherein the control filter is further coupled to receive the trimmed current signal and operable, in response to the speed error signal and the trimmed current signal, to supply the operational control signals.

6. The system of claim 5, wherein each motor/generator controller is further coupled to receive a reference voltage signal, and a signal representative of the electrical supply system voltage.

7. The system of claim 6, wherein the speed comparator circuit is further operable to supply a trimmed speed signal based on one of the motor/generator rotational speed signals, and wherein the control filter circuit comprises:

a voltage error circuit coupled to receive the reference voltage signal, the signal representative of electrical supply system voltage, the speed error signal, and the trimmed current signal from one of the motor generators and operable, in response thereto, to supply a voltage error signal;

a voltage filter coupled to receive the voltage error signal and operable, in response thereto, to supply a current command signal;

a current error circuit coupled to receive the current command signal and the motor/generator current signal from one of the motor/generators and operable, in response thereto, to supply a current error signal;

a current filter coupled to receive the current error signal and operable, in response thereto, to supply a speed command signal; and

a control signal supply circuit coupled to receive the speed command signal and the trimmed channel speed signal and operable, in response thereto, to supply the operational control signals.

8. The system of claim 7, further comprising:

an operational mode select circuit coupled to receive the voltage error signal and operable, in response thereto, to supply a mode control signal,

wherein the control logic circuit is further coupled to receive the mode control signal and operable, in response thereto, to control the operation of one of the motor/generators in either the motor mode or the generate mode.

9. The system of claim 7, wherein the system comprises three or more flywheels, three or motor/generators, and three or more motor/generator controllers.

10. In a system having a plurality of energy storage flywheels configured to supply one or more signals representative of flywheel operational parameters, and a plurality of motor/generators each coupled to one of the energy storage flywheels and an electrical supply system and configured to supply a plurality of signals representative of a motor/generator operational parameter, a method of regulating bus voltage in the electrical supply system, comprising:

controlling each motor/generator based at least in part on a plurality of the motor/generator operational parameter signals supplied from each of the motor/generators to thereby regulate the electrical supply system bus voltage and substantially equally share electrical load between the motor/generators.

11. The method of claim 10, further comprising:

selectively controlling each of the motor/generators in either a motor mode, whereby electrical energy from the electrical supply system is converted to rotational kinetic energy and supplied to an energy storage flywheel, or a generate mode, whereby rotational kinetic energy from an energy storage flywheel is converted to electrical energy and supplied to the electrical supply system.

12. The method of claim 10, wherein the motor/generator operational parameter signals supplied by each motor/generator include a motor/generator rotational speed signal, and wherein the method further comprises:

comparing each motor/generator rotational speed signal with one or more other motor/generator rotational speed signals to determine a speed error for each motor/generator; and

controlling each motor/generator based at least in part on its determined speed error.

13. The method of claim 12, wherein the motor/generator operational parameter signals supplied by each motor/generator further include motor/generator current, and wherein the method further comprises:

controlling each motor/generator based at least in part on its determined speed error and its motor/generator current.

14. The method of claim 13, further comprising:

determining a voltage error for each motor/generator based at least in part on a reference voltage, the electrical supply system voltage, its determined speed error, and its determined motor/generator current,

determining a desired current magnitude for each motor/generator based at least in part on its determined voltage error;

determining a current error for each motor/generator based at least in part on its desired current magnitude and its motor/generator current;

determining a desired rotational speed for each motor generator based at least in part on the current error;

determining an energization duty cycle time for each motor/generator based at least in part on its desired rotational speed; and

supplying electrical power to each motor/generator for its determined energization duty cycle time.

15. The method of claim 14, further comprising:

controlling each motor/generator in either the motor mode or the generator mode based at least in part on its determined voltage error.

16. A satellite, comprising:

an electrical power distribution bus;

a main controller coupled to receive at least a voltage command signal and operable, in response thereto, to supply a voltage reference signal;

a plurality of energy storage flywheels;

a plurality of motor/generators, each motor/generator coupled to one of the energy storage flywheels and to the electrical supply system and configured to operate in either (i) a motor mode, whereby electrical energy from the electrical supply system is converted to rotational kinetic energy and supplied to its respective energy storage flywheel or (ii) a generate mode, whereby rotational kinetic energy from its respective energy storage flywheel is converted to electrical energy and supplied to the electrical supply system, each motor/generator further configured to supply a plurality of signals, each signal representative of a motor/generator operational parameter; and

a plurality of motor/generator controllers, each motor/generator controller coupled to receive a plurality of the motor/generator operational parameter signals from each of the motor/generators and the voltage reference signal and operable, in response thereto, to control operation of one of the motor/generators in either the motor mode or the generate mode, to thereby regulate voltage on the electrical power distribution bus and substantially equally share electrical load between the motor/generators.