Method of controlling hybrid construction machine and hybrid construction machine

• US 8,439,139 B2
• Filed: 03/27/2008
• Issued: 05/14/2013
• Est. Priority Date: 03/28/2007
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Morinaga, Jun, Kawaguchi, Tadashi, Inoue, Hiroaki
• Primary Examiner(s): PHAN, HAU VAN
• Application Number:
  US12/450,444
• Publication Number:
  US 20100071973A1
• Time in Patent Office: 1,874 Days
• Field of Search: 180/65.1, 180/65.265, 180/65.285, 180/65.275, 180/65.21, 318/432, 318/139, 318/376, 318/140, 320/104, 320/132
• US Class Current: 180/65.265
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/427 Voltage
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/24 by lever actuation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60Y 2200/412 : Excavators
• CPC Class Codes: E02F 9/123 : Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• CPC Class Codes: E02F 9/2058 : Electric or electro-mechanical or mechanical control devices of vehicle sub-units for vehicles in general B60W
• CPC Class Codes: E02F 9/2075 : of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2091 : Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: F02D 29/06 : peculiar to engines driving electric generators
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A method of controlling a hybrid construction machine capable of preventing a system from being rendered inoperative without increasing a capacitance of a capacitor and of inhibiting delay of a swing operation relative to an operation command at the time of swing operation, and the hybrid construction machine are provided. For this purpose, at the time of discharge of the capacitor, actual torque command values are respectively generated by referring to an assist torque limit value corresponding to capacitor voltage of a generator motor and a swing power running torque limit value corresponding to the capacitor voltage of a swing motor, as well as, at the time of charge of the capacitor, an actual target output value of the generator motor is generated.

Claims

1. A method of controlling a hybrid construction machine provided with an engine and a generator motor coupled to each other, a swing motor which electric power is supplied to from the generator motor for swinging a part of a body relative to other parts, a capacitor for storing the electric power generated by each of the generator motor and the swing motor and supplying the electric power to the generator motor and the swing motor, and a booster for boosting voltage of the capacitor to output, the method comprising:

an assist torque limit value calculating step of calculating an assist torque limit value of the generator motor corresponding to capacitor voltage of the capacitor when the booster performs an output associated with discharge of the capacitor;

a generator motor torque command value calculating step of calculating a torque command value of the generator motor according to a target speed of the generator motor; and

a generator motor actual torque command value generating step of comparing the assist torque limit value calculated at the assist torque limit value calculating step with the torque command value calculated at the generator motor torque command value calculating step, and generating an actual torque command value of the generator motor by using the smaller of the assist torque limit value and the torque command value.

2. The method of controlling the hybrid construction machine according to claim 1, wherein the assist torque limit value is zero when the capacitor voltage is not larger than a first threshold, and gradually increases as the capacitor voltage becomes larger than the first threshold to take a constant value when the capacitor voltage is not smaller than a second threshold larger than the first threshold.

3. The method of controlling the hybrid construction machine according to claim 1, wherein

in the generator motor torque command value calculating step, the torque command value of the generator motor is calculated by performing proportional control, in which an actual speed of the generator motor is fed back.

4. The method of controlling the hybrid construction machine according to claim 1, further comprising:

a swing power running torque limit value calculating step of calculating a swing power running torque limit value of the swing motor corresponding to the capacitor voltage when the booster performs the output associated with the discharge of the capacitor;

a swing motor torque command value calculating step of calculating a torque command value of the swing motor according to a target speed of the swing motor; and

a swing motor actual torque command value generating step of comparing the swing power running torque limit value calculated at the swing power running torque limit value calculating step with the torque command value calculated at the swing motor torque command value calculating step and generating an actual torque command value of the swing motor by using the smaller of the swing power running torque limit value and the torque command value.

5. The method of controlling the hybrid construction machine according to claim 4, wherein

the swing power running torque command value is zero when the capacitor voltage is not larger than a third threshold, which is smaller than the first threshold, and gradually increases as the capacitor voltage becomes larger than the third threshold to take a constant value when the capacitor voltage is not smaller than a fourth threshold, which is larger than the third threshold.

6. The method of controlling the hybrid construction machine according to claim 4, wherein

in the swing motor torque command value calculating step, the torque command value of the swing motor is calculated by performing proportional control, in which an actual speed of the swing motor is fed back.

7. The method of controlling the hybrid construction machine according to claim 1, comprising:

a booster output limit value calculating step of calculating an output limit value of the booster corresponding to the capacitor voltage when the booster performs an output associated with charge of the capacitor;

a generator motor output limit value calculating step of calculating an output limit value of the generator motor by using the output limit value calculated at the booster output limit value calculating step and an output of the swing motor;

an actual target output value generating step of comparing the output limit value of the generator motor calculated at the generator motor output limit value calculating step with a target output value of the generator motor and generating an actual target output value of the generator motor by using the smaller of the output limit value of the generator motor and a target output value of the generator motor; and

a charge time generator motor actual torque command value generating step of generating the actual torque command value of the generator motor by using the actual target output value generated at the actual target output value generating step and a motor speed of the generator motor.

8. A hybrid construction machine provided with an engine and a generator motor coupled to each other, a swing motor which electric power is supplied to from the generator motor for swinging a part of a body relative to other parts, a capacitor for storing the electric power generated by each of the generator motor and the swing motor and supplying the electric power to the generator motor and the swing motor, and a booster for boosting voltage of the capacitor to output, comprising:

a capacitor voltage measuring unit for successively measuring capacitor voltage of the capacitor; and

a controlling unit for calculating an assist torque limit value of the generator motor corresponding to the capacitor voltage measured by the capacitor voltage measuring unit, while calculating a torque command value of the generator motor according to a target speed of the generator motor, and for comparing the assist torque limit value with the torque command value of the generator motor, and generating an actual torque command value of the generator motor to output by using the smaller of the assist torque limit value and the torque command value of the generator motor, when the booster performs an output associated with discharge of the capacitor.

9. The hybrid construction machine according to claim 8, wherein

the controlling unit, while calculating a swing power running torque limit value of the swing motor corresponding to the capacitor voltage measured by the capacitor voltage measuring unit, calculates a torque command value of the swing motor according to a target speed of the swing motor, compares the swing power running torque limit value with the torque command value of the swing motor, and generates an actual torque command of the swing motor to output by using the smaller of the swing power running torque limit value and the torque command value of the swing motor, when the booster performs the output associated with the discharge of the capacitor.

10. The hybrid construction machine according to claim 8, wherein

the controlling unit calculates an output limit value of the booster corresponding to the capacitor voltage measured by the capacitor voltage measuring unit, obtains an output limit value of the generator motor by using the calculated output limit value and the output of the swing motor, compares the output limit value with a target output value of the generator motor, and generates an actual target output value of the generator motor to output by using a smaller of the output limit value and a target output value of the generator motor, when the booster performs an output associated with charge of the capacitor.

11. A method of controlling a hybrid construction machine comprising an engine, a swing motor for swinging a part of a body relative to other parts, and a capacitor for storing the electric power generated by the swing motor and supplying the electric power to the swing motor, the method comprising:

a swing power running torque limit value calculating step of calculating a swing power running torque limit value of the swing motor corresponding to the capacitor voltage;

a swing motor torque command value calculating step of calculating a torque command value of the swing motor according to a target speed of the swing motor; and

a swing motor actual torque command value generating step of comparing the swing power running torque limit value calculated at the swing power running torque limit value calculating step with the torque command value calculated at the swing motor torque command value calculating step and generating an actual torque command value of the swing motor by using the smaller of the swing power running torque limit value and the torque command value.