Motor controller for a hydraulic pump with electrical regeneration

• US 6,652,239 B2
• Filed: 08/29/2002
• Issued: 11/25/2003
• Est. Priority Date: 03/29/2001
• Status: Expired due to Fees

• Current Assignee: Kadant Incorporated
• Original Assignee: Kadant Incorporated
• Inventors: Carstensen, Peter T.
• Primary Examiner(s): Tyler, Cheryl J.
• Assistant Examiner(s): Solak, Timothy P.
• Application Number:
  US10/230,469
• Publication Number:
  US 20020197166A1
• Time in Patent Office: 453 Days
• Field of Search: 417/53, 417/9, 417/43, 417/44.11, 417/45, 604/14, 604/31
• US Class Current: 417/44.11
• CPC Class Codes: F04B 11/00 Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
• CPC Class Codes: F04B 2201/1202 Torque on the axis
• CPC Class Codes: F04B 2201/1208 Angular position of the shaft
• CPC Class Codes: F04B 2203/0204 Frequency of the electric current
• CPC Class Codes: F04B 2203/0207 Torque
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/20 by changing the driving speed

Abstract

Disclosure is made of a precision hydraulic energy delivery system that directly couples the pump to a primary mover (motor) and a related motor control. The system provides flow control of a hydraulically driven machine without the use of downstream devices by employing motion control algorithms in the motor control. Control features are electronically integrated into the hydraulic system by using control algorithms and subroutines specifically developed for the prime mover servo control system coupled to the pump.

Claims

1. A pump system comprising:

a pump for pumping a fluid;

a drive motor directly coupled to said pump; and

a motor control coupled to said pump for controlling said drive motor;

said motor control employing a motion control algorithm to control a hydraulic output at an input shaft of the pump,

wherein the algorithm includes a subroutine for calculating a magnitude of a pump shaft torque output and translating the torque output into a pressure delivered signal.

2. The system of claim 1, wherein said drive motor is operable to both drive the pump and to generate energy using the hydraulic output.

3. The system of claim 1, further comprising means for storing electrical energy including reclaimed energy from regeneration.

4. The system of claim 1, wherein the algorithm further includes a subroutine for detecting a pump leakage rate and outputting an alarm when a predetermined leakage limit is exceeded.

5. A pump system comprising:

a pump for pumping a fluid;

a drive motor directly coupled to said pump; and

a motor control coupled to said pump for controlling said drive motor;

said motor control employing a motion control algorithm to control a hydraulic output of the pump, wherein any excess hydraulic output is used to generate electrical energy when a pressure spike occurs;

the electrical energy being stored in an energy storage means, said generation and storage of electrical energy resulting in the elimination of the pressure spike.

6. A pump system comprising:

a pump for pumping a fluid;

a drive motor directly coupled to said pump; and

a motor control coupled to said pump for controlling said drive motor;

said motor control employing a motion control algorithm to control a hydraulic output of the pump,

wherein the algorithm includes a subroutine for overriding existing hydraulic output settings when a pressure droop occurs so that the pressure droop is eliminated.

7. A pump system comprising:

a pump for pumping a fluid;

a drive motor directly coupled to said pump; and

a motor control coupled to said pump for controlling said drive motor;

said motor control employing a motion control algorithm to control a hydraulic output of the pump, wherein the algorithm includes a subroutine for maintaining a constant horsepower from the drive motor, thereby limiting hydraulic output to an application.

8. A pump system comprising:

a pump for pumping a fluid;

a drive motor directly coupled to said pump; and

a motor control coupled to said pump for controlling said drive motor;

said motor control employing a motion control algorithm to control a hydraulic output of the pump, wherein the algorithm includes a subroutine for assessing a pump output level and applying a profile of torque vs. velocity corresponding to the assessed output level.

9. A method for controlling a pump, comprising the steps of:

determining a reference polar guide of torque profile compared to an angular displacement of an input shaft of said pump;

measuring an angular position of a pump drive shaft in operation;

comparing said angular position with said reference polar guide;

selecting a corresponding torque command value from the comparison of the angular position with the polar guide; and

powering the pump to provide a constant output pressure.