HYBRID CONSTRUCTION MACHINE AND METHOD OF CONTROLLING HYBRID CONSTRUCTION MACHINE

• US 20100270095A1
• Filed: 12/26/2008
• Published: 10/28/2010
• Est. Priority Date: 12/26/2007
• Status: Active Grant

• Current Assignee: Sumitomo Heavy Industries Limited
• Original Assignee: Sumitomo Heavy Industries Limited
• Inventors: Shono, Hiroso, Kanbayashi, Hideaki
• Granted Patent: US 8,544,576 B2
• Time in Patent Office: Days
• US Class Current: 180/65.290
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60W 10/06 including control of combustion engines
• 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 2050/001 Proportional integral [PI] controller
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60Y 2200/41 Construction vehicles, e.g. graders, 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 9/2075 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: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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

Abstract

A hybrid construction machine including an internal combustion engine, a motor generator, a hydraulically driven working element, and a rotation mechanism rotationally driven by a rotation electric motor includes a charge storage part provided between the motor generator and the rotation electric motor, wherein the charge storage part includes a constant voltage charge storage part configured to maintain its voltage value within a certain range; and a variable voltage charge storage part configured to tolerate a variation in the voltage value of the charge storage part due to the electric motor and the generator operation of the motor generator or the power running and the regenerative operation of the rotation electric motor.

Claims

1. A hybrid construction machine including an internal combustion engine, a motor generator, a hydraulically driven working element, and a rotation mechanism rotationally driven by a rotation electric motor, the hybrid construction machine comprising:

a charge storage part provided between the motor generator and the rotation electric motor,

wherein the charge storage part includes a constant voltage charge storage part configured to maintain a voltage value thereof within a certain range; and

a variable voltage charge storage part configured to tolerate a variation in a voltage value of the charge storage part due to an electric motor and a generator operation of the motor generator or a power running and a regenerative operation of the rotation electric motor.

2. The hybrid construction machine as claimed in claim 1, further comprising:

a step-up and step-down converter having a first side thereof connected to the constant voltage charge storage part and having a second side thereof connected to the variable voltage charge storage part, the step-up and step-down converter being configured to raise or lower the voltage value of the constant voltage charge storage part by varying a voltage value of the variable voltage charge storage part; and

a step-up and step-down drive control part configured to control switching of a voltage raising operation and a voltage lowering operation of the step-up and step-down converter.

3. The hybrid construction machine as claimed in claim 2, further comprising:

a voltage value detecting part configured to detect the voltage value of the constant voltage charge storage part,

wherein the step-up and step-down drive control part is configured to control the switching of the voltage raising operation and the voltage lowering operation based on the voltage value detected by the voltage value detecting part.

4. The hybrid construction machine as claimed in claim 2, wherein the step-up and step-down drive control part is configured to control the switching of the voltage raising operation and the voltage lowering operation in accordance with an operating state of the rotation electric motor so that the voltage value of the constant voltage charge storage part falls within the certain range.

5. The hybrid construction machine as claimed in claim 2, wherein the step-up and step-down drive control part is configured to provide a time of no operation in switching one to another of the voltage raising operation and the voltage lowering operation of the step-up and step-down converter.

6. The hybrid construction machine as claimed in claim 3, wherein:

the step-up and step-down converter includes

a step-up switching device for controlling a supply of electric power from the variable voltage charge storage part to the constant voltage charge storage part;

a step-down switching device for controlling a supply of electric power from the constant voltage charge storage part to the variable voltage charge storage part; and

a reactor connected to the step-up switching device and the step-down switching device, and

the step-up and step-down drive control part includes

a voltage control part configured to control driving of the step-up switching device or the step-down switching device so that the voltage value of the voltage value detecting part becomes a voltage target value;

a current control part configured to control driving of the step-up switching device or the step-down switching device so that a value of a current flowing through the reactor becomes a predetermined current threshold; and

a control switching part configured to perform switching selectively to one of the voltage control part and the current control part so that a load on the step-up and step-down converter becomes less than or equal to a predetermined load.

7. The hybrid construction machine as claimed in claim 6, wherein the control switching part is configured to perform switching to a drive control by the current control part in response to an absolute value of the current flowing through the reactor becoming greater than the current threshold during performance of a drive control by the voltage control part.

8. The hybrid construction machine as claimed in claim 6, wherein the control switching part is configured to perform switching to a drive control by the voltage control part in response to the voltage value of the voltage value detecting part returning to the voltage target value during performance of a drive control by the current control part.

9. The hybrid construction machine as claimed in claim 6, wherein in switching one to another of the voltage control part and the current control part, the step-up and step-down drive control part is configured to correct an initial value of a control target value after the switching.

10. The hybrid construction machine as claimed in claim 2, wherein the step-up and step-down drive control part is configured to perform such control as to increase a charging or discharge current in a dead zone region of the step-up and step-down converter.

11. The hybrid construction machine as claimed in claim 2, wherein the step-up and step-down drive control part comprises:

a main control part configured to calculate a PWM duty value for driving the step-up and step-down converter so that the voltage value of the constant voltage charge storage part follows a target voltage value;

a compensation duty value calculating part configured to calculate a compensation duty value for compensating for the PWM duty value in a predetermined low current region in a current value characteristic of the step-up and step-down converter relative to the PWM duty value; and

a combining part configured to perform a combining operation of combining the compensation duty value with the PWM duty value calculated by the main control part.

12. The hybrid construction machine as claimed in claim 11, wherein the main control part is configured to calculate the PWM duty value by PI control based on a deviation between the voltage value of the constant voltage charge storage part and the target voltage value, further comprises a replacing part configured to replace an integral component value included in the PWM duty value with an opposite of a proportional component value at a time of starting an activation of the combining operation.

13. The hybrid construction machine as claimed in claim 11, wherein the compensation duty value calculating part is configured to calculate, as the compensation duty value, a duty value corresponding to the PWM duty value at an inflection point on a step-up side or a step-down side in the current value characteristic of the step-up and step-down converter relative to the PWM duty value.

14. A method of controlling a hybrid construction machine including an internal combustion engine, a motor generator, a hydraulically driven working element, a rotation mechanism rotationally driven by a rotation electric motor, and a charge storage part provided between the motor generator and the rotation electric motor and including a constant voltage charge storage part and a variable voltage charge storage part, wherein:

the constant voltage charge storage part maintains a voltage value thereof within a certain range; and

the variable voltage charge storage part tolerates a variation in a voltage value of the charge storage part due to an electric motor and a generator operation of the motor generator or a power running and a regenerative operation of the rotation electric motor.