Energy management apparatus and method for injection molding systems

• US 7,176,648 B2
• Filed: 05/18/2004
• Issued: 02/13/2007
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: Husky Injection Molding Systems Limited
• Original Assignee: Husky Injection Molding Systems Limited
• Inventors: Choi, Christopher Wai-Ming
• Primary Examiner(s): Masih; Karen
• Application Number:
  US10/847,663
• Publication Number:
  US 20050258795A1
• Time in Patent Office: 1,001 Days
• Field of Search: 318/625, 318/370, 318/372, 318/373, 318/376, 318/700, 318/832, 318/375, 318/377, 318/106, 318/109, 318/382, 187/290, 187/296, 290/4.R, 290/7
• US Class Current: 318/625
• CPC Class Codes: B29C 2045/1792 Machine parts driven by an electric motor, e.g. electric servomotor
• CPC Class Codes: B29C 2045/7673 Recovering energy or power from drive motors
• CPC Class Codes: B29C 2045/824 Accumulators
• CPC Class Codes: B29C 2945/76006 Pressure
• CPC Class Codes: B29C 2945/76033 Electric current or voltage
• CPC Class Codes: B29C 2945/76083 Position
• CPC Class Codes: B29C 2945/7611 Velocity
• CPC Class Codes: B29C 2945/76307 hydraulic fluids
• CPC Class Codes: B29C 2945/76454 Electrical, e.g. thermocouples
• CPC Class Codes: B29C 2945/76498 Pressure
• CPC Class Codes: B29C 2945/76511 Torque
• CPC Class Codes: B29C 2945/76518 Energy, power
• CPC Class Codes: B29C 2945/76525 Electric current or voltage
• CPC Class Codes: B29C 2945/76531 Temperature
• CPC Class Codes: B29C 2945/76545 Flow rate
• CPC Class Codes: B29C 2945/76595 Velocity
• CPC Class Codes: B29C 2945/76785 hydraulic fluids
• CPC Class Codes: B29C 2945/76876 Switch-over
• CPC Class Codes: B29C 2945/76936 The operating conditions are corrected in the next phase or cycle
• CPC Class Codes: B29C 2945/76966 and integral, i.e. Pl regulation
• CPC Class Codes: B29C 45/7666 : of power or energy, e.g. integral function of force
• CPC Class Codes: G05B 2219/31135 : Fieldbus
• CPC Class Codes: G05B 2219/32021 : Energy management, balance and limit power to tools
• CPC Class Codes: G05B 2219/34403 : RTI real time, kernel, processing
• CPC Class Codes: G05B 2219/45244 : Injection molding
• CPC Class Codes: Y02P 70/10 : Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• CPC Class Codes: Y02P 80/10 : Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
• CPC Class Codes: Y02P 90/02 : Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

An energy management control apparatus for a molding machine that includes a first electrically-driven prime mover configured to drive at least a first molding machine device, and a second electrically-driven prime mover configured to drive at least a second molding machine device, includes a common DC link configured to provide DC energy to the first electrically-driven prime mover and to the second electrically-driven prime mover. A slave axis is configured to supply and absorb energy from to/from the common DC link. A machine controller is configured to (i) communicate with the first electrically-driven prime mover, the second electrically-driven prime mover, the common DC link, and the slave axis, (ii) cause the slave axis to supply energy to the common DC link in response to input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover, and (iii) cause the slave axis to absorb energy from the common DC link in response to input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover.

Claims

1. Injection molding machine energy management control apparatus for controlling at least one of (i) a first electrically-driven prime mover configured to drive at least a first molding machine device, and (ii) a second electrically-driven prime mover configured to drive at least a second molding machine device, said control apparatus comprising:

a common DC link configured to provide DC energy to the first electrically-driven prime mover and to the second electrically-driven prime mover;

a slave axis configured to supply energy to and absorb energy from said common DC link;

a non-electrical energy accumulation structure coupled to said slave axis and configured to supply energy to, and absorb energy from, said common DC link; and

a machine controller configured to (i) communicate with the first electrically-driven prime mover, the second electrically-driven prime mover, said common DC link, and said slave axis, (ii) cause said slave axis to supply energy to said common DC link in response to input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover, and (iii) cause said slave axis to absorb energy from said common DC link in response to input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover.

2. Control apparatus according to claim 1, further comprising a high speed, bi-directional communication fieldbus configured to provide communication between said machine controller and said first electrically-driven prime mover, said second electrically-driven prime mover, said common DC link, and said slave axis.

3. Control apparatus according to claim 1, wherein said machine controller, in response to the input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover, generates command signals in real-time to cause said slave axis to supply and absorb energy to/from said common DC link.

4. Control apparatus according to claim 1, further comprising a torque controller configured to (i) control said slave axis in a normal speed control mode, and in a DC link voltage control mode, and (ii) switch between the two control modes in a bumpless transfer manner.

5. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, which is configured to drive a hydraulic pumping assembly, and wherein said machine controller is configured to regulate a flow rate and a pressure of a hydraulic fluid supply of the hydraulic pumping assembly.

6. Control apparatus according to claim 5, further comprising the second electrically-driven prime mover, which is configured to drive an electrically-driven actuator, and wherein said machine controller is configured to regulate current and voltage supplied to said the actuator.

7. Control apparatus according to claim 1, wherein said energy accumulation structure comprises mechanical energy accumulation device.

8. Control apparatus according to claim 7, wherein said mechanical energy accumulation device comprises a flywheel.

9. Control apparatus according to claim 1, wherein said energy accumulation structure comprises a hydraulic energy accumulation device configured to store and release energy through receipt and release of hydraulic fluid.

10. Control apparatus according to claim 9, further comprising a fixed displacement pump configured to supply hydraulic fluid to said hydraulic energy accumulation device.

11. Control apparatus according to claim 9, further comprising a variable displacement pump configured to supply hydraulic fluid to said hydraulic energy accumulation device.

12. Control apparatus according to claim 1, further comprising:

a first inverter configured to provide AC power to the first electrically-driven prime mover; and

a second inverter configured to provide AC power to the second electrically-driven prime mover;

wherein said common DC link is configured to provide DC energy to said first and second inverters.

13. Control apparatus according to claim 8, further comprising:

a first drive controller configured to provide adjustable speed drive to the first electrically-driven prime mover; and

a second drive controller configured to provide adjustable speed drive to the second electrically-driven prime mover;

wherein said machine controller is configured to control said first and second drive controllers.

14. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, and wherein said first electrically-driven prime mover comprises an induction motor.

15. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, and wherein said first electrically-driven prime mover comprises a permanent magnet synchronous motor.

16. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, and wherein said first electrically-driven prime mover comprises a switched reluctance motor.

17. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, and wherein said first electrically-driven prime mover comprises an adjustable speed drive, and wherein said machine controller controls said adjustable speed drive with field oriented control.

18. Control apparatus according to claim 1, further comprising the first electrically-driven prime mover, and wherein said first electrically-driven prime mover comprises an adjustable speed drive, and wherein said machine controller controls said adjustable speed drive with direct torque control.

19. Control apparatus according to claim 1, further comprising sensor structure configured to sense a rotor position of the first electrically-driven prime mover, and to provide the sensed rotor position to said machine controller.

20. Control apparatus according to claim 1, further comprising estimating structure configured to estimate a rotor position of the first electrically-driven prime mover, and to provide the estimated rotor position to said machine controller.

21. Control apparatus according to claim 1, further comprising:

a heater configured to absorb energy from said common DC link; and

an inverter, controlled by said machine controller, and configured to regulate electrical power to said heater to control the temperature of a corresponding heating zone.

22. An injection molding system control apparatus, comprising:

a first electrically-driven prime mover configured to drive at least a first molding machine device;

a second electrically-driven prime mover configured to drive at least a second molding machine device;

a common DC link configured to provide DC energy to said first electrically-driven prime mover and to said second electrically-driven prime mover;

a slave axis configured to supply and absorb energy from to/from said common DC link;

a non-electrical energy accumulation structure configured to supply energy to said common DC link, and to absorb energy from said common DC link; and

a machine controller configured to (i) communicate with said first electrically-driven prime mover, said second electrically-driven prime mover, said common DC link, and said slave axis, (ii) cause said slave axis to supply energy to said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover, and (iii) cause said slave axis to absorb energy from said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover.

23. Control apparatus according to claim 22, further comprising a high speed, bi-directional communication fieldbus configured to provide communication between said machine controller and said first electrically-driven prime mover, said second electrically-driven prime mover, said common DC link, and said slave axis.

24. Control apparatus according to claim 22, wherein said machine controller, in response to the input from at least one of the first electrically-driven prime mover and the second electrically-driven prime mover, generates command signals in real-time to cause said slave axis to supply and absorb energy from to/from said common DC link.

25. Control apparatus according to claim 22, further comprising a torque controller configured to (i) control said slave axis in a normal speed control mode, and in a DC link voltage control mode, and (ii) switch between the two control modes in a bumpless transfer manner.

26. Control apparatus according to claim 22, wherein said first electrically-driven prime mover is configured to drive a hydraulic pumping assembly, and wherein said machine controller is configured to regulate a flow rate and a pressure of a hydraulic fluid supply of the hydraulic pumping assembly.

27. Control apparatus according to claim 22, wherein said energy accumulation structure comprises mechanical energy accumulation device.

28. Control apparatus according to claim 27, wherein said mechanical energy accumulation structure comprises a flywheel.

29. Control apparatus according to claim 22, wherein said energy accumulation structure comprises a hydraulic energy accumulation device configured to store and release energy through receipt and release of hydraulic fluid.

30. Control apparatus according to claim 29, further comprising a fixed displacement pump configured to supply hydraulic fluid to said hydraulic energy accumulation structure.

31. Control apparatus according to claim 29, further comprising a variable displacement pump configured to supply hydraulic fluid to said hydraulic energy accumulation structure.

32. Control apparatus according to claim 22, further comprising:

a first inverter configured to provide AC power to said first electrically-driven prime mover; and

a second inverter configured to provide AC power to said second electrically-driven prime mover;

wherein said common DC link is configured to provide DC energy to said first and second inverters.

33. Control apparatus according to claim 32, further comprising:

a first drive controller configured to provide adjustable speed drive to said first electrically-driven prime mover; and

a second drive controller configured to provide adjustable speed drive to said second electrically-driven prime mover;

wherein said machine controller is configured to control said first and second drive controllers.

34. Control apparatus according to claim 22, wherein said first electrically-driven prime mover comprises an induction motor.

35. Control apparatus according to claim 22, wherein said first electrically-driven prime mover comprises a permanent magnet synchronous motor.

36. Control apparatus according to claim 22, wherein said first electrically-driven prime mover comprises a switched reluctance motor.

37. Control apparatus according to claim 22, wherein said first electrically-driven prime mover comprises an adjustable speed drive, and wherein said machine controller controls said adjustable speed drive with field oriented control.

38. Control apparatus according to claim 22, wherein said first electrically-driven prime mover comprises an adjustable speed drive, and wherein said machine controller controls said adjustable speed drive with direct torque control.

39. Control apparatus according to claim 22, further comprising sensor structure to sense a rotor position of said first electrically-driven prime mover, and to provide the sensed rotor position to said machine controller.

40. Control apparatus according to claim 22, further comprising estimating structure to estimate a rotor position of said first electrically-driven prime mover, and to provide the estimated rotor position to said machine controller.

41. Control apparatus according to claim 22, further comprising:

a heater configured to absorb energy from said common DC link; and

an inverter, controlled by said machine controller, and configured to regulate electrical power to said heater to control the temperature of a corresponding heating zone.

42. An injection molding system control apparatus, comprising:

a first electrically-driven prime mover configured to drive a hydraulic molding machine device;

a second electrically-driven prime mover configured to drive at least another molding machine device;

a common DC link configured to provide DC energy to said first electrically-driven prime mover and to said second electrically-driven prime mover;

a slave axis configured to supply and absorb energy from to/from said common DC link;

a machine controller configured to (i) communicate with said first electrically-driven prime mover, said second electrically-driven prime mover, said common DC link, and said slave axis, (ii) cause said slave axis to supply energy to said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover, and (iii) cause said slave axis to absorb energy from said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover; and

a hydraulic energy accumulation structure, coupled to said first electrically-driven prime mover, and configured to store and release energy through receipt and release of hydraulic fluid.

43. An injection molding system control apparatus, comprising:

a first electrically-driven prime mover configured to drive a mechanical molding machine device;

a second electrically-driven prime mover configured to drive at least another molding machine device;

a common DC link configured to provide DC energy to said first electrically-driven prime mover and to said second electrically-driven prime mover;

a slave axis configured to supply and absorb energy from to/from said common DC link;

a machine controller configured to (i) communicate with said first electrically-driven prime mover, said second electrically-driven prime mover, said common DC link, and said slave axis, (ii) cause said slave axis to supply energy to said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover, and (iii) cause said slave axis to absorb energy from said common DC link in response to input from at least one of said first electrically-driven prime mover and said second electrically-driven prime mover; and

a flywheel, coupled to said first electrically-driven prime mover, and configured to store and release energy through movement of said flywheel.

44. Energy management apparatus for a molding machine having (i) a first motor configured to drive a first molding machine device, and (ii) a second motor configured to drive a second molding machine device, said apparatus comprising:

an electrical link coupled to the first motor and to the second motor;

non-electrical energy storage structure configured to (i) store excess energy from at least one of the first motor and the second motor, and (ii) provide stored excess energy to at least one of the first molding machine device and the second molding machine device; and

processing structure configured to cause (i) excess energy from the first motor to be stored in said energy storage structure, and (ii) excess energy stored in said energy storage structure to be used to drive at least the first molding machine device.

45. Apparatus according to claim 44, wherein said processing structure causes excess energy stored in said energy storage structure to be transmitted to the second motor through said electrical link.

46. Apparatus according to claim 45, wherein said energy storage device comprises a flywheel coupled to the first motor, and wherein excess energy stored in said flywheel causes the first motor to generate excess electricity which is provided to said electrical link.

47. Apparatus according to claim 44, wherein the first molding machine device comprises a hydraulic device, and wherein said energy storage device comprises a hydraulic accumulator configured to store excess energy as a greater hydraulic pressure, and wherein said greater hydraulic pressure is used to drive the hydraulic device.

48. Apparatus according to claim 44, wherein said processing structure causes excess energy generated by the first motor to be supplied to the second motor, through said electrical link.

49. Apparatus according to claim 44, wherein said processing structure causes energy used by the first and second motors to be balanced at their respective lowest load requirements.

50. An injection molding machine, comprising:

a mold;

a mold clamp having a mold clamp actuator;

a mold screw having a mold screw actuator;

an electrical link coupling said mold clamp actuator and said mold screw actuator;

an non-electrical energy accumulator coupled to at least one of said mold clamp actuator and said mold screw actuator; and

energy management processing structure configured to cause (i) excess energy from at least one of said mold clamp actuator and said mold screw actuator to be stored in said energy accumulator, and (ii) energy stored in said energy accumulator to be provided to at least one of said mold clamp actuator and said mold screw actuator.

51. An injection molding machine according to claim 50, wherein said energy management structure causes the stored excess energy to be transmitted through said electrical link.

52. An injection molding machine according to claim 50, wherein said electrical link comprises a DC link, and further comprising a first inverter coupled to said mold clamp actuator, and a second inverter coupled to said mold screw actuator.

53. A method for managing energy in a molding machine having a first actuator for driving a first molding device and a second actuator for driving a second molding device, said method comprising the steps of:

receiving from the first actuator an input signal corresponding to the energy status of the first actuator;

receiving from the second actuator an input signal corresponding to the energy status of the second actuator;

calculating an excess energy condition of any of the first actuator and the second actuator based on the received input signals;

calculating an insufficient energy condition of any of the first actuator and the second actuator based on the received input signals;

based on the calculation, providing excess energy from at least one of the first actuator and the second actuator to an energy accumulation device; and

based on the calculation, providing excess energy from the energy accumulation device to at least one of the first actuator and the second actuator.

54. A method according to claim 53, wherein the step of providing excess energy from the energy accumulation device includes the step of providing the excess energy to at least one of the first actuator and the second actuator over a DC link.

55. A method according to claim 53, wherein the step of providing excess energy to the energy accumulation device includes the step of providing the excess energy to a hydraulic accumulator.

56. A method according to claim 53, wherein the step of providing excess energy from the energy accumulation device includes the step of providing the excess energy from a hydraulic accumulator.

57. A method according to claim 53, wherein the step of providing excess energy to the energy accumulation device includes the step of providing the excess energy to a flywheel.

59. A method according to claim 53, wherein the step of providing excess energy from the energy accumulation device includes the step of providing the excess energy from a flywheel.

58. A computer readable medium containing instructions which cause a processing structure in a molding machine that has (i) a first actuator for driving a first molding device and (ii) a second actuator for driving a second molding device, to perform the following steps:

receiving from the first actuator an input signal corresponding to the energy status of the first actuator;

receiving from the second actuator an input signal corresponding to the energy status of the second actuator;

calculating an excess energy condition of any of the first actuator and the second actuator based on the received input signals;

calculating an insufficient energy condition of any of the first actuator and the second actuator based on the received input signals;

based on the calculation, causing excess energy from at least one of the first actuator and the second actuator to be provided to an energy accumulation device; and

based on the calculation, causing excess energy from the energy accumulation device to be provided to at least one of the first actuator and the second actuator.