JP5808779B2 - Excavator - Google Patents

Description

  The present invention relates to an excavator provided with a controller that measures the internal resistance of a battery that is repeatedly charged and discharged.

  Conventionally, as a battery used as a secondary battery, there is a capacitor that electrostatically accumulates or discharges electric charge. The capacitor accumulates or discharges electric energy by repeatedly charging and discharging according to the demand of the load.

  Conventionally, a capacitor used as a secondary battery has been used for various purposes (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 2002-50409

  However, in many work machines driven by a capacitor, in the motor generator driven when the capacitor is charged and discharged, the motor (assist) operation and the power generation operation of the motor generator are frequently repeated during work. In particular, when power control of a motor generator is performed, it is difficult to control to a constant current by controlling a capacitor or the like whose voltage changes depending on the charging rate.

  Therefore, an object of the present invention is to provide a shovel that can measure the internal resistance value by using the operation of the shovel.

According to one aspect, the lower traveling body;
An upper swing body mounted on the lower traveling body via a swing mechanism;
A boom mounted on the upper swing body;
A boom cylinder mounted on the upper swing body for driving the boom;
A main pump for supplying hydraulic pressure to the boom cylinder;
An engine connected to the main pump;
A motor generator connected to the engine and the main pump;
A battery for storing electric power generated by the motor generator via a converter ;
In a shovel comprising a controller for measuring the internal resistance of the capacitor,
The controller
During shovel work, based on the presence or absence of the operation of the operation device, it determines whether and said converter operation shovel rather free becomes inoperative state is in an idling state not driven,
Measuring the first current value and the first stored voltage value of the battery when the non-working state is determined;
Thereafter, when the storage device is energized, the second current value and the second storage voltage value of the storage device are measured,
Based on the current difference obtained by the second current value and the first current value and the voltage difference obtained by the second storage voltage value and the first storage voltage value, the internal resistance of the battery is An excavator characterized by calculating is provided.

  According to the present invention, it is possible to provide a shovel capable of measuring an internal resistance value of a capacitor during normal operation of a load without providing a special function for measuring an internal resistance value. It is done.

It is a side view which shows the hybrid type construction machine to which the measuring method and internal resistance measuring apparatus of Embodiment 1 are applied. It is a block diagram showing the structure of the hybrid type construction machine to which the internal resistance measuring method and internal resistance measuring apparatus of Embodiment 1 are applied. It is a figure which shows the electric power control circuit of Embodiment 1 applied to the hybrid type construction machine demonstrated in FIG.1 and FIG.2. FIG. 3 is a diagram showing an equivalent circuit of a battery 19 in the first embodiment. It is a characteristic view for demonstrating the measurement principle of the internal resistance value by the measuring method of the internal resistance of the capacitor | condenser of Embodiment 1, and shows the relationship between the waveform of the voltage value and electric current value required for a measurement, and SOC. FIG. 6 is a diagram showing a procedure for deriving an internal resistance value by a method for measuring the internal resistance of the battery according to the first embodiment. It is a characteristic view for demonstrating the measurement principle of the internal resistance value by the measuring method of the internal resistance of the capacitor | condenser of Embodiment 2, and shows the relationship between the waveform of the voltage value and electric current value required for a measurement, and SOC. It is a characteristic view for demonstrating the measurement principle of the internal resistance value by the measuring method of the internal resistance of the capacitor | condenser of Embodiment 3, and shows the relationship between the waveform of a voltage value and electric current value required for a measurement, and SOC.

  Hereinafter, an embodiment in which a method for measuring internal resistance of a capacitor and an internal resistance measuring device of the present invention are applied will be described. Here, in order to make it easy to understand the processing contents of the internal resistance measuring method and the internal resistance measuring device of the first embodiment, the internal resistance measuring method and the internal resistance measuring device of the first embodiment are applied to a hybrid construction machine. An example (application example) will be described.

[Embodiment 1]
In describing an application example of a hybrid construction machine to which the internal resistance measurement method and the internal resistance measurement device according to the first embodiment are applied, first, a basic configuration of the hybrid construction machine will be described with reference to FIGS. 1 and 2. .

  FIG. 1 is a side view showing a hybrid construction machine to which the internal resistance measuring method and the internal resistance measuring apparatus according to Embodiment 1 are applied.

  An upper swing body 3 is mounted on the lower traveling body 1 of this hybrid construction machine via a swing mechanism 2. In addition to the boom 4, the arm 5, and the bucket 6, and the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 for hydraulically driving them, the upper swing body 3 is equipped with a cabin 10 and a power source. Is done.

[overall structure]
FIG. 2 is a block diagram illustrating a configuration of a hybrid construction machine to which the internal resistance measuring method and the internal resistance measuring apparatus according to the first embodiment are applied. In FIG. 2, the mechanical power system is indicated by a thick solid line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a solid line.

  An engine 11 as a mechanical drive unit and a motor generator 12 as an assist drive unit are both connected to an input shaft of a speed reducer 13 as a booster. A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16.

  The control valve 17 is a control device that controls the hydraulic system in the construction machine according to the first embodiment. The control valve 17 includes hydraulic motors 1A (for right) and 1B (for left) for the lower traveling body 1, The boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are connected via a high pressure hydraulic line.

  The motor generator 12 is connected to a battery 19 as a battery via an inverter 18 and a step-up / down converter 100. The inverter 18 and the buck-boost converter 100 are connected by a DC bus 110.

  In addition, a turning electric motor 21 is connected to the DC bus 110 via an inverter 20. The DC bus 110 is disposed for transferring power between the battery 19, the motor generator 12, and the turning motor 21.

  The DC bus 110 is provided with a DC bus voltage detector 111 for detecting a voltage value of the DC bus 110 (hereinafter referred to as a DC bus voltage value). The detected DC bus voltage value is input to the controller 30.

  Further, the battery 19 is provided with a battery voltage detection unit 106 for detecting the battery voltage value and a battery current detection unit 107 for detecting the battery current value. The battery voltage value and battery current value detected by these are input to the controller 30.

  A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21. An operation device 26 is connected to the pilot pump 15 through a pilot line 25.

  A control valve 17 and a pressure sensor 29 as a lever operation detection unit are connected to the operating device 26 via hydraulic lines 27 and 28, respectively. The pressure sensor 29 is connected to a controller 30 that performs drive control of the electric system of the construction machine according to the first embodiment.

  The construction machine according to the first embodiment is a hybrid construction machine that uses the engine 11, the motor generator 12, and the turning electric motor 21 as power sources. These power sources are mounted on the upper swing body 3 shown in FIG. Hereinafter, each part will be described.

[Configuration of each part]
The engine 11 is an internal combustion engine composed of, for example, a diesel engine, and its output shaft is connected to one input shaft of the speed reducer 13. The engine 11 is always operated during the operation of the construction machine.

  The motor generator 12 may be an electric motor capable of both electric (assist) operation and power generation operation. Here, a motor generator that is AC driven by an inverter 20 is shown as the motor generator 12. The motor generator 12 can be constituted by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in a rotor. The rotating shaft of the motor generator 12 is connected to the other input shaft of the speed reducer 13.

  The speed reducer 13 has two input shafts and one output shaft. A drive shaft of the engine 11 and a drive shaft of the motor generator 12 are connected to each of the two input shafts. Further, the drive shaft of the main pump 14 is connected to the output shaft. When the load on the engine 11 is large, the motor generator 12 performs an electric driving (assist) operation, and the driving force of the motor generator 12 is transmitted to the main pump 14 via the output shaft of the speed reducer 13. Thereby, driving of the engine 11 is assisted. On the other hand, when the load of the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 through the speed reducer 13, so that the motor generator 12 generates power by the power generation operation. Switching between the electric operation and the power generation operation of the motor generator 12 is performed by the controller 30 according to the load of the engine 11 and the like.

  The main pump 14 is a pump that generates hydraulic pressure to be supplied to the control valve 17. This hydraulic pressure is supplied to drive each of the hydraulic motors 1 </ b> A and 1 </ b> B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 via the control valve 17.

  The pilot pump 15 is a pump that generates a pilot pressure necessary for the hydraulic operation system. The configuration of this hydraulic operation system will be described later.

  The control valve 17 inputs the hydraulic pressure supplied to each of the hydraulic motors 1A, 1B, the boom cylinder 7, the arm cylinder 8 and the bucket cylinder 9 for the lower traveling body 1 connected via a high-pressure hydraulic line. It is a hydraulic control device which controls these hydraulically by controlling according to the above.

  The inverter 18 is provided between the motor generator 12 and the buck-boost converter 100 as described above, and controls the operation of the motor generator 12 based on a command from the controller 30. Thus, when the inverter 18 is electrically driving the motor generator 12, necessary power is supplied from the battery 19 and the step-up / down converter 100 to the motor generator 12 via the DC bus 110. Further, when the motor generator 12 is in a power generation operation, the battery 19 is charged with the electric power generated by the motor generator 12 via the DC bus 110 and the step-up / down converter 100.

  The battery 19 is connected to the inverter 18 and the inverter 20 via the step-up / down converter 100. Thereby, when at least one of the electric (assist) operation of the motor generator 12 and the power running operation of the turning electric motor 21 is performed, electric power necessary for the electric (assist) operation or the power running operation is supplied. In addition, when at least one of the power generation operation of the motor generator 12 and the regenerative operation of the turning motor 21 is performed, the electric power generated by the power generation operation or the regenerative operation is stored as electric energy. Is the power source.

  The charge / discharge control of the battery 19 is based on the charge state of the battery 19, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state (powering operation or regenerative operation) of the turning motor 21. This is done by the buck-boost converter 100. The switching control between the step-up / step-down operation of the step-up / step-down converter 100 is performed by controlling the DC bus voltage value detected by the DC bus voltage detection unit 111, the battery voltage value detected by the battery voltage detection unit 106, and the battery current detection unit 107. Is performed by the controller 30 based on the battery current value detected by.

  The inverter 20 is provided between the turning electric motor 21 and the step-up / down converter 100 as described above, and performs operation control on the turning electric motor 21 based on a command from the controller 30. Thereby, when the inverter is operating and controlling the power running of the turning electric motor 21, necessary electric power is supplied from the battery 19 to the turning electric motor 21 through the step-up / down converter 100. Further, when the turning electric motor 21 is performing a regenerative operation, the battery 19 is charged with the electric power generated by the turning electric motor 21 via the step-up / down converter 100. FIG. 2 shows an embodiment including a swing motor (1 unit) and an inverter (1 unit), but by providing a drive unit other than the magnet mechanism and the swing mechanism unit, a plurality of motors and a plurality of inverters are provided. It may be connected to the DC bus 110.

  The buck-boost converter 100 has one side connected to the motor generator 12 and the turning electric motor 21 via the DC bus 110 and the other side connected to the battery 19, so that the DC bus voltage value is within a certain range. Thus, control for switching between step-up and step-down is performed. When the motor generator 12 performs an electric driving (assist) operation, it is necessary to supply electric power to the motor generator 12 via the inverter 18, and thus it is necessary to boost the DC bus voltage value. On the other hand, when the motor generator 12 performs a power generation operation, it is necessary to charge the battery 19 through the inverter 18 with the generated power, and thus it is necessary to step down the DC bus voltage value. The same applies to the power running operation and the regenerative operation of the turning electric motor 21. In addition, the operation state of the motor generator 12 is switched according to the load state of the engine 11, and the turning electric motor 21 is changed to the upper turning body 3. Since the driving state is switched in accordance with the turning operation, the motor generator 12 and the turning motor 21 are either in an electric (assist) operation or a power running operation, and the other is in a power generation operation or a regenerative operation. Can occur.

  For this reason, the step-up / step-down converter 100 performs control to switch between the step-up operation and the step-down operation so that the DC bus voltage value falls within a certain range according to the operating state of the motor generator 12 and the turning electric motor 21. This control method will be described with reference to FIG.

  The DC bus 110 is disposed between the two inverters 18 and 20 and the step-up / down converter, and is configured to be able to transfer power between the battery 19, the motor generator 12, and the turning electric motor 21. Yes.

  The DC bus voltage detection unit 111 is a voltage detection unit for detecting a DC bus voltage value. The detected DC bus voltage value is input to the controller 30, and is used for switching control between the step-up operation and the step-down operation for keeping the DC bus voltage value within a certain range.

  The battery voltage detection unit 106 is a voltage detection unit for detecting the voltage value of the battery 19 and is used for detecting the state of charge of the battery. The detected battery voltage value is input to the controller 30 and used for switching control between the step-up / step-down operation of the step-up / step-down converter 100.

  The battery current detection unit 107 is a current detection unit for detecting the current value of the battery 19. As the battery current value, a current flowing from the battery 19 to the step-up / down converter 100 is detected as a positive value. The detected battery current value is input to the controller 30 and used for switching control between the step-up / step-down operation of the step-up / down converter 100.

  The turning electric motor 21 may be an electric motor capable of both power running operation and regenerative operation, and is provided for driving the turning mechanism 2 of the upper turning body 3. During the power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the speed reducer 24, and the upper turning body 3 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the upper swing body 3, the number of rotations is increased by the speed reducer 24 and transmitted to the turning electric motor 21, and regenerative power can be generated. Here, as the electric motor 21 for turning, an electric motor driven by an inverter 20 by a PWM (Pulse Width Modulation) control signal is shown. The turning electric motor 21 can be constituted by, for example, a magnet-embedded IPM motor. Thereby, since a larger induced electromotive force can be generated, the electric power generated by the turning electric motor 21 at the time of regeneration can be increased.

  The resolver 22 is a sensor that detects the rotational position and the rotational angle of the rotating shaft 21A of the turning electric motor 21, and is mechanically connected to the turning electric motor 21 to rotate the rotating shaft 21A before the turning electric motor 21 rotates. The rotation angle and the rotation direction of the rotation shaft 21A are detected by detecting the difference between the position and the rotation position after the left rotation or the right rotation. By detecting the rotation angle of the rotation shaft 21A of the turning electric motor 21, the rotation angle and the rotation direction of the turning mechanism 2 are derived. Further, FIG. 2 shows a form in which the resolver 22 is attached, but an inverter control system that does not have an electric motor rotation sensor may be used.

  The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21 </ b> A of the turning electric motor 21. This mechanical brake 23 is switched between braking and release by an electromagnetic switch. This switching is performed by the controller 30.

  The turning speed reducer 24 is a speed reducer that reduces the rotational speed of the rotating shaft 21 </ b> A of the turning electric motor 21 and mechanically transmits it to the turning mechanism 2. Thereby, in the power running operation, the rotational force of the turning electric motor 21 can be increased and transmitted to the turning body as a larger rotational force. On the contrary, during the regenerative operation, the number of rotations generated in the revolving structure can be increased, and more rotational motion can be generated in the turning electric motor 21.

  The turning mechanism 2 can turn in a state where the mechanical brake 23 of the turning electric motor 21 is released, whereby the upper turning body 3 is turned leftward or rightward.

  The operation device 26 is an operation device for operating the turning electric motor 21, the lower traveling body 1, the boom 4, the arm 5, and the bucket 6, and includes levers 26A and 26B and a pedal 26C. The lever 26 </ b> A is a lever for operating the turning electric motor 21 and the arm 5, and is provided in the vicinity of the driver seat of the upper turning body 3. The lever 26B is a lever for operating the boom 4 and the bucket 6, and is provided in the vicinity of the driver's seat. The pedals 26C are a pair of pedals for operating the lower traveling body 1, and are provided under the feet of the driver's seat.

  The operating device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into hydraulic pressure (secondary hydraulic pressure) corresponding to the operation amount of the driver and outputs the converted hydraulic pressure. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27 and detected by the pressure sensor 29.

  When each of the levers 26A and 26B and the pedal 26C is operated, the control valve 17 is driven through the hydraulic line 27, whereby the hydraulic pressure in the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8 and the bucket cylinder 9 is increased. Is controlled, the lower traveling body 1, the boom 4, the arm 5, and the bucket 6 are driven.

  The hydraulic line 27 supplies hydraulic pressure necessary for driving the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder to the control valve.

  In the pressure sensor 29, an operation of the lever 26A for operating the turning electric motor 21 and the arm 5, an operation of the lever 26B for operating the arm 4 and the bucket 6, and an operation of the pedal 26C for causing the lower traveling body 1 to travel. Is input, this amount of operation is detected as a change in hydraulic pressure in the hydraulic line 28. The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28, and this electrical signal is input to the controller 30. Thereby, the controller 30 can detect the presence or absence of operation of the lower traveling body 1, the arm 4, the arm 5, the bucket 6, and the turning electric motor 21.

  In addition, since the hybrid construction machine of the first embodiment electrically drives the turning mechanism 2, the controller 30 accurately grasps the operation amount of the lever 26A for turning the turning mechanism 2 input from the pressure sensor 29. Can do.

  In the first embodiment, a mode in which the pressure sensor 29 is used as the operation detection unit will be described. However, a sensor that directly reads an operation amount input to the operation device 26 with an electric signal may be used.

[Controller 30]
The controller 30 is a control device that performs drive control of the hybrid construction machine according to the first embodiment, includes a turning drive control unit 40 and a drive control unit 120, and includes arithmetic processing including a CPU (Central Processing Unit) and an internal memory. The apparatus is configured by an apparatus and realized by a CPU executing a drive control program stored in an internal memory.

  The controller 30 detects whether or not the lower traveling body 1, the arm 4, the arm 5, the bucket 6, and the turning electric motor 21 are operated based on an electric signal input from the pressure sensor 29. Moreover, since the controller 30 also performs charge / discharge control in a power control circuit described later, the controller 30 is configured to detect a non-working state of the hybrid construction machine. The detection of the non-working state is a state where none of the lower traveling body 1, the arm 4, the arm 5, the bucket 6, and the turning electric motor 21 is operated, and neither charging nor discharging is performed. .

  In addition, the controller 30 has a function of operating the engine 11 for a predetermined short period of time in order to pass an internal resistance measurement current to the battery 19 in a non-working state.

  The turning drive control unit 40 converts a signal inputted from the pressure sensor 29 (a signal representing an operation amount for turning the turning mechanism 2 inputted to the operation device 26) into a speed command, and drives the turning electric motor 21. Take control.

  The drive control unit 120 is a control device for performing operation control of the motor generator 12 (switching between electric (assist) operation or power generation operation) and charge / discharge control of the battery 19 by driving control of the step-up / down converter 100. It is. The drive control unit 120 moves up and down based on the state of charge of the battery 19, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state of the turning motor 21 (power running operation or regenerative operation). Switching control between the step-up operation and the step-down operation of the voltage converter 100 is performed, and thereby the charge / discharge control of the battery 19 is performed.

  The switching control between the step-up / step-down operation of the step-up / step-down converter 100 is performed by controlling the DC bus voltage value detected by the DC bus voltage detection unit 111, the battery voltage value detected by the battery voltage detection unit 106, and the battery current detection unit 107. Is performed by the controller 30 based on the battery current value detected by the controller 30.

  The state in which neither charging nor discharging is performed refers to a state in which the buck-boost converter 100 is not used.

  FIG. 3 is a diagram illustrating the power control circuit according to the first embodiment applied to the hybrid construction machine described with reference to FIGS. 1 and 2. This power control circuit includes a step-up / down converter 100, a DC bus 110, a motor 120, and a battery 19. The battery 19 is a capacitor whose internal resistance value is measured by the internal resistance measurement device of the first embodiment.

  The step-up / down converter 100 includes a reactor 101, a boosting IGBT (Insulated Gate Bipolar Transistor) 102A, a step-down IGBT 102B, a power connection terminal 103 for connecting a battery 19, an output terminal 104 for connecting a motor 120, and a pair of outputs. A smoothing capacitor 105 inserted in parallel with the terminal 104, a battery voltage detection unit 106, and a battery current detection unit 107 are provided.

  The output terminal 104 of the buck-boost converter 100 and the motor 120 are connected by a DC bus 110. The battery 19 corresponds to the battery 19 in FIG. 2, and the motor 120 corresponds to the motor generator 12 and the turning electric motor 21 in FIG. In FIG. 3, the inverters 18 and 20 (see FIG. 2) are omitted for simplification of the drawing.

  Reactor 101 has one end connected to an intermediate point between boosting IGBT 102A and step-down IGBT 102B, and the other end connected to power supply connection terminal 103, so that induced electromotive force generated when ON / OFF of boosting IGBT 102A is generated. It is provided for supplying to the DC bus 9.

  The step-up IGBT 102 </ b> A and the step-down IGBT 102 </ b> B are semiconductor elements that are configured by a bipolar transistor in which a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is incorporated in a gate portion and can perform high-power high-speed switching. The step-up IGBT 102A and the step-down IGBT 102B are driven by applying a PWM voltage from the controller 30 to the gate terminal. Diodes 102a and 102b, which are rectifier elements, are connected in parallel to the step-up IGBT 102A and the step-down IGBT 102B.

  Here, the drive control (charge / discharge switching control) of the step-up IGBT 102A and the step-down IGBT 102B is performed by the controller 30. For this reason, in the controller 30, switching between charge and discharge by the step-up IGBT 102A and the step-down IGBT 102B is detected.

  Here, the term “switching of charge / discharge” refers to switching from a discharged state to a charged state, switching from a charged state to a discharged state, switching from a state in which charging / discharging is not performed to a charged state or discharged state, Alternatively, it is used to represent switching from a charged state or a discharged state to a state where charging / discharging is not performed, and this is the same in the scope of claims.

  The battery 19 may be a chargeable / dischargeable battery so that power can be exchanged with the DC bus 110 via the buck-boost converter 100. 3 shows the battery 19 as a capacitor, the capacitor 19 may be replaced with a capacitor, a chargeable / dischargeable secondary battery, or another form of power source capable of power transfer. Good.

  The power connection terminal 103 and the output terminal 104 may be terminals that can connect the battery 19 and the motor 120. A battery voltage detection unit 106 that detects a battery voltage is connected between the pair of power connection terminals 103. A DC bus voltage detector 111 that detects a DC bus voltage is connected between the pair of output terminals 104.

  The battery voltage detection unit 106 detects the voltage value Vm of the battery 19, and the DC bus voltage detection unit 111 detects the voltage of the DC bus 110 (hereinafter, DC bus voltage Vdc).

  The motor 120 that is a load connected to the output terminal 104 may be an electric motor capable of power running operation and regenerative operation. For example, the motor 120 may be configured by an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. it can. Although FIG. 3 shows a motor 120 for direct current drive, it may be a motor driven by alternating current through an inverter.

  The smoothing capacitor 105 may be any storage element that is inserted between the positive terminal and the negative terminal of the output terminal 104 and can smooth the DC bus voltage.

  The battery current detection unit 107 may be a detection unit capable of detecting the value of the current flowing through the battery 19 and includes a current detection resistor. The battery current detection unit 107 detects a current value I flowing through the battery 19.

  In the first embodiment, the current value in the direction in which current is supplied from battery 19 to DC bus 110 is positive, and the current value in the direction in which current is supplied from DC bus 110 to battery 19 is negative. That is, the current value when discharging the battery 19 is positive, and the current value when charging the battery 19 is negative.

[Buck-boost operation]
In such a step-up / down converter 100, when boosting the DC bus 110, a PWM voltage is applied to the gate terminal of the boosting IGBT 102A, and the boosting IGBT 102A is connected via the diode 102b connected in parallel to the step-down IGBT 102B. The induced electromotive force generated in the reactor 101 when the power is turned on / off is supplied to the DC bus 110. Thereby, the DC bus 110 is boosted.

  When the DC bus 110 is stepped down, a PWM voltage is applied to the gate terminal of the step-down IGBT 102B, and regenerative power generated by the motor 120 is supplied from the DC bus 110 to the battery 19 via the step-down IGBT 102B. . As a result, the power stored in the DC bus 110 is charged in the battery 19 and the DC bus 110 is stepped down.

  Here, when applied to the hybrid construction machine, the buck-boost converter 100 of the first embodiment has a voltage value of the battery 19 of about 100 to 500 V, an output rated voltage at the output terminal 104 of about 200 to 400 V, and a rated output. : About several tens of kW, instantaneous maximum output power: ± 100 kW, rated current: ± 100 A, and instantaneous maximum current: ± 100 A.

[Measurement of internal resistance]
The internal resistance value of the battery 19 (battery 19) is measured by the controller 30.

  FIG. 4 is a diagram showing an equivalent circuit of the battery 19 in the first embodiment. The battery 19 can be divided into a capacity 131 and an internal resistance 132. The inter-terminal voltage value Vm of the battery 19 is the sum of the charging voltage value Vc of the capacitor 131 and the voltage drop Vr at the internal resistor 132. Here, when the resistance value of the internal resistor 132 is R and the current flowing through the battery 19 is I, it can be expressed as Vr = R × I.

  In the method for measuring the internal resistance of the battery according to the first embodiment, the current value I1 flowing through the battery 19 of the hybrid construction machine in the non-working state (no-load state), and the voltage value V1 between the terminals of the battery 19 at this time The battery 19 is charged by causing the motor generator 12 to generate power by performing constant rotation of the engine 11 in the non-working state, and the current value I2 flowing to the battery 19 at this time and the current value of the battery 19 The internal resistance value R of the battery 19 is derived from the equation (1) using the inter-terminal voltage value V2.

R = (V2-V1) / (I2-I1) (1)
In this measuring method, the battery 19 is charged and discharged as in the non-working state of the hybrid construction machine as the working machine to which the internal resistance measuring method and the internal resistance measuring device of the first embodiment are applied. In such a state, the value of the current flowing through the battery 19 is substantially zero and no voltage drop occurs due to the internal resistance (for this reason, the voltage between the terminals of the battery 19 is equal to the charge voltage of the capacity component of the battery 19). When charging is started from a non-working state, a voltage drop occurs in the internal resistance due to the current that flows to accumulate the electric charge in the battery 19, so that the change in the voltage value corresponding to this voltage drop value ( This is a measurement method in which a resistance value obtained by dividing V2-V1) by a change in current value (I2-I1) is derived as an internal resistance value of the battery 19.

  Note that the inter-terminal voltage value of the battery 19 is detected by the battery voltage detection unit 106, and the current value is detected by the battery current detection unit 107.

  FIG. 5 is a characteristic diagram for explaining the measurement principle of the internal resistance value by the internal resistance measurement method of the capacitor of Embodiment 1, and shows the relationship between the voltage value and current value waveforms required for measurement and the SOC. Show.

  The period from time t = 0 to t1 is a period in which the battery 19 is being charged because the current value is negative. At this time, the SOC gradually increases.

  During the period from time t = t1 to t2, the value of the current flowing through the battery 19 is substantially zero, and the battery 19 is not loaded / discharged. The working machine at this time is in a non-working state, and the engine 11 is in an idling state in which a constant rotation speed is maintained. Since the voltage value becomes substantially constant at V1, the SOC has a substantially constant value, and the state of charge of the battery 19 is a very stable state in which the current value maintains a value within a threshold value not shown. When a predetermined period elapses, the engine 11 generates power (discharge) by driving the motor 120 with a constant rotational speed, and creates a current pattern for measurement.

  The period from time t = t2 to t3 is a standby period until the current is stabilized due to the controllability of the converter at the start of power generation (discharge). At this time, the SOC is gradually increasing again. When the current value for energizing the battery 19 reaches a predetermined current value, it is determined that the current is stable, and the current value and the voltage value are measured (time t = t3).

  During the period from time t = t3 to t4, the current flowing through the battery 19 is also stable, and the SOC rises linearly.

  Note that t2 to t3 are tens of milliseconds, and t3 to t4 are time intervals of tens to hundreds of milliseconds.

  The controller 30 measures the voltage V1 between the terminals of the battery 19 and the current value I1 at the last time t = t2 in the non-working state, and the voltage between the terminals of the battery 19 at time t = t3 when the power generation amount is constant in the charged state. V2 and current value I2 are measured, and the internal resistance value of battery 19 is measured using equation (1).

  For example, the controller 30 samples the voltage value and current value between terminals at a cycle of 5 milliseconds, so that data indicating the voltage value V1 between terminals and the current value I1 at time t = t2 or immediately after that is input. In addition, data representing the inter-terminal voltage value V2 and the current value I2 at or after time t = t3 is input.

  FIG. 6 is a diagram showing a procedure for deriving an internal resistance value by the method for measuring the internal resistance of the battery according to the first embodiment. This process is executed by the CPU of the controller 30.

  The controller 30 determines whether or not the work machine is in a non-working state (step S1). Based on the electric signal input from the pressure sensor 29, the controller 30 is not operated for any of the lower traveling body 1, the arm 4, the arm 5, the bucket 6, and the turning electric motor 21, and is used for boosting. When it is detected that neither the IGBT 102A nor the step-down IGBT 102B is driven, it is determined that it is in a non-working state. The process of step S1 is repeatedly executed until a non-working state is detected.

  When detecting the non-working state in step S1, the controller 30 determines whether or not the SOC is a constant value (step S2). If it is determined that the SOC is not a constant value, the procedure returns to step S1.

  Then, when the current value maintains a substantially zero value within the threshold, the controller 30 determines that the battery 19 is in a no-load state. When a predetermined time elapses and time t = t2, the controller 30 measures the inter-terminal voltage value V1 and the current value I1 (step S3). Data representing the measured inter-terminal voltage value V1 and current value I1 is stored in the internal memory of the controller 30.

  Next, a current is allowed to flow until a voltage drop occurs in the inter-terminal voltage V. When the predetermined current value I2 is reached, the terminal voltage V2 at that time (t = t3) is measured (step S4). Here, the current value I2 is determined in advance so that power generation (discharge) of the capacitor 131 does not occur. Data representing the measured inter-terminal voltage value V2 and current value I2 is stored in the internal memory of the controller 30. In addition, after the start of power generation (discharge) of the motor generator 12 (t = t2), the voltage V2 between the terminals and the current value I2 at that time are measured when a predetermined time has elapsed (t = t3). You may do it.

  The controller 30 reads the inter-terminal voltage values V1 and V2 and the current values I1 and I2 measured in steps S3 and S4 from the internal memory, and derives an internal resistance value using the equation (1) (step S5).

  Thus, the measurement process by the method for measuring the internal resistance of the battery of Embodiment 1 is completed.

  According to the method for measuring the internal resistance of the electric storage device of the first embodiment, the operation of the hybrid construction machine is used, and the voltage between the terminals at the time of non-working and at the time of charging, with the state of charge (SOC) of the battery 19 being high, Based on the difference between the current values, the internal resistance value of the battery 19 (the resistance value R of the internal resistance 132) can be derived.

  In addition, when the method for measuring the internal resistance of the capacitor and the internal resistance measurement device according to Embodiment 1 are applied to a hybrid construction machine that uses a motor generator that is driven and controlled based on the charging rate of the battery, the charging rate If it fluctuates, it is difficult to control the power generation (discharge) current of the motor generator to be constant.

  According to the method of the first embodiment, the terminal voltage at the time of non-working and charging can be obtained simply by operating the engine 11 at a constant rotation and causing the motor generator 12 to generate power without passing a constant current. Since the internal resistance value of the battery 19 (resistance value R of the internal resistance 132) can be derived based on the difference between the current value and the current value, the internal resistance value of the battery 19 (resistance of the internal resistance 132 is accurately determined even in a hybrid construction machine). The value R) can be measured.

  The controller 30 performs drive control of the battery 19 (battery 19), the inverter 18, the inverter 20, and the step-up / down converter 100, and in particular, charge / discharge of the battery 19 (battery 19) by controlling the drive of the step-up / down converter 100. If the resistance value R of the internal resistance 132 is periodically derived and stored in the internal memory because the control is performed, for example, the battery charge rate (SOC: It is possible to realize a control process for changing the state of charge.

  In addition, by monitoring the deterioration of the battery 19, when the battery charge rate (SOC: State Of Charge) is in a state where the predetermined value cannot be achieved, an alarm process that outputs an alarm for replacement time is realized. be able to.

[Embodiment 2]
FIG. 7 is a characteristic diagram for explaining the principle of measurement of the internal resistance value by the method for measuring the internal resistance of the capacitor according to the second embodiment. The relationship between the voltage value and current value waveforms necessary for measurement and the SOC is shown. Show. The measuring method and the internal resistance measuring device for the internal resistance of the capacitor according to the second embodiment can be applied to the hybrid construction machine shown in FIGS. 1 and 2 as in the first embodiment. For this reason, the same or similar components are denoted by the same reference numerals, and the description thereof is omitted. Also, the description of the reference numerals common to FIG. 5 is omitted.

  The voltage values (V1, V2) and current values (I1, I2) that are actually detected by the hybrid construction machine are waveforms having a swing width as shown in FIG. For this reason, when the above-described method for deriving the internal resistance value is used, it may be possible to derive a more accurate internal resistance value by using the average value for both the voltage value and the current value.

  For this reason, in the second embodiment, a plurality of inter-terminal voltage values V1 between time t = t1 and t2 are sampled, and the average value V1 * is used.

  Similarly, a plurality of inter-terminal voltage values V2 from time t = t3 to t4 are sampled, and the average value V2 * is used.

  For the current value, a plurality of current values I1 between time t = t1 and t2 are sampled, and the average value I1 * is used.

  Similarly, a plurality of current values I2 from time t = t3 to t4 are sampled, and the average value I2 * is used. Here, the time t = t4 may be a time after elapse of a predetermined time from t3, or may be a time when the detected current value becomes a predetermined current value.

  The controller 30 derives the resistance value R of the internal resistance 132 by substituting the average values V1 *, V2 *, I1 *, and I2 * into the equation (1).

  Note that the voltage values (V1, V2) and current values (I1, I2) sampled to derive the above average value are stored in the internal memory of the controller 30 and read when calculating the average value.

  As described above, according to the method for measuring the internal resistance value of battery 19 (resistance value R of internal resistance 132) according to the second embodiment, even if the voltage waveform and the current waveform have fluctuations as shown in FIG. By using the average value of the voltage value and the current value, the internal resistance value of the battery 19 (the resistance value R of the internal resistance 132) can be accurately derived.

[Embodiment 3]
FIG. 8 is a characteristic diagram for explaining the principle of measurement of the internal resistance value by the method of measuring the internal resistance of the capacitor according to the third embodiment. The relationship between the voltage value and current value waveforms necessary for measurement and the SOC is shown. Show. In addition, description of the code | symbol which is common in FIG.

  The third embodiment is different from the second embodiment in that an accurate internal resistance value is derived by using the least square method for the voltage value and current value processing instead of using the average value for the voltage value and current value processing. Different.

  For this reason, in the third embodiment, a plurality of inter-terminal voltage values V1 from time t = t1 to t2 are sampled, and a straight line l1 that best fits the sample is calculated using the least square method for the sampled values. In this straight line l1, a value V1 at time t = t2 is obtained.

  Similarly, a plurality of inter-terminal voltage values V2 from time t = t3 to t4 are sampled, and a straight line l2 that best fits the sample is calculated using the sampled value using the least square method. On this straight line l2, the value V2 at time t = t3 is obtained.

  As for the current value, a plurality of current values I1 from time t = t1 to t2 are sampled, and a straight line k1 that best fits the sample is calculated using the least square method for the sampled values. A value I1 at time t = t2 is obtained on this straight line k1.

  Similarly, a plurality of current values I2 from time t = t3 to t4 are sampled, and a straight line k2 that best fits the sample is calculated using the least square method for the sampled values. On this straight line k2, the value I2 at time t = t3 is obtained. Here, the time t = t4 may be a time after elapse of a predetermined time from t3, or may be a time when the detected current value becomes a predetermined current value.

  The controller 30 derives the resistance value R of the internal resistor 132 by substituting the values V1, V2, I1, and I2 obtained by the least square method into the equation (1).

  Note that the sampled voltage values (V1, V2) and current values (I1, I2) are stored in the internal memory of the controller 30, and are read when performing an operation by the method of least squares.

  As described above, according to the method for measuring the internal resistance value of battery 19 (resistance value R of internal resistance 132) according to the third embodiment, even when the voltage waveform and the current waveform are not stable as shown in FIG. By using the least squares method for the value processing, the voltage value and the current value at the start and end of switching of charging / discharging can be obtained by calculation, so that the internal resistance value of the battery 19 (the internal resistance 132 The resistance value R) can be derived.

  In the above description, the method of using the PI control for the control system of the hybrid construction machine to which the internal resistance measuring method and the internal resistance measuring device of the first to third embodiments are applied has been described. The control is not limited to hysteresis control, robust control, adaptive control, proportional control, integral control, gain scheduling control, or sliding mode control.

  In the above description, the internal resistance measuring method and the internal resistance measuring device according to the first to third embodiments when applied to a hybrid construction machine have been described. The application target of the measuring method and the internal resistance measuring device is not limited to the battery 19 mounted on the hybrid type construction machine. If charging / discharging is performed, the internal resistance value of the battery included in various devices is derived. Can do.

  Moreover, although the hybrid type construction machine to which the internal resistance measuring method and the internal resistance measuring device according to the first to third embodiments are applied has been described above, the hybrid type working machine as an application example is other than the construction machine. For example, it may be a hybrid type transporting and handling machine (a crane or a forklift).

  For example, the engine 11 and the motor generator 12 shown in FIG. 2 are used as a crane engine and an assist motor generator, and the turning electric motor 21 shown in FIG. Can be used as a power source. In particular, the power source for raising or lowering parts, cargo, etc. is used as a hybrid work machine because it performs powering operation (when winding) and regenerative operation (when pulling) along with winding or pulling out the wire. It can be implemented in the same manner as the hybrid construction machine described above.

  Similarly, in the case of a forklift, the engine 11 and motor generator 12 shown in FIG. 2 are used as a forklift engine and an assist motor generator, and the turning electric motor 21 shown in FIG. Alternatively, it may be used as a power source for lowering. In particular, the power source for raising or lowering the fork performs a power running operation (when winding) and a regenerative operation (when pulling) in accordance with the up-and-down movement, so that it is the same as the above-described hybrid construction machine as a hybrid work machine Can be implemented.

  As mentioned above, although the excavator of the exemplary embodiment of the present invention has been described, the present invention is not limited to the specifically disclosed embodiment, and various types can be made without departing from the scope of the claims. Can be modified or changed.

  For example, the method for measuring the internal resistance of a capacitor according to one aspect of the present invention is a method for measuring the internal resistance of a capacitor that is used as a power source via a motor generator during work of a work machine, and the capacitor is in an unloaded state. A first current value and a first stored voltage value are measured at the time, and the battery is energized by the motor generator, and the second current value and the second stored voltage value in the energized state of the capacitor. And measuring the battery based on the current difference obtained from the second current value and the first current value, and the voltage difference obtained from the second stored voltage value and the first stored voltage value. The internal resistance is calculated.

  Further, the first current value and the first stored voltage value may be measured when a charging rate of the battery is equal to or greater than a predetermined value.

  The first current value may be measured after it is determined that the current value is within a threshold range.

  The motor generator may perform a motor generator operation based on a charging rate of the battery.

  The work machine includes an engine that performs a power generation operation of the motor generator. The motor generator is energized in a state where the engine maintains a constant rotation speed, and the second current value and the first The storage voltage value of 2 may be measured.

  Further, the first and second current values and the first and second stored voltage values may be measured when the work machine is in a non-working state.

  An internal resistance measurement device according to one aspect of the present invention is an internal resistance measurement device that measures an internal resistance of a capacitor used as a power source via a motor generator during work of a work machine, and the capacitor is in an unloaded state. A first measurement unit for measuring the first current value and the first storage voltage value, a control unit for energizing the capacitor by the motor generator, and a second current in the energization state of the capacitor A second measurement unit for measuring the value and the second storage voltage value, a current difference obtained from the second current value and the first current value, the second storage voltage value and the first storage And an internal resistance calculator that calculates an internal resistance of the battery based on a voltage difference obtained by a voltage value.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Hydraulic motor 2 Turning mechanism 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Reducer 14 Main pump 15 Pilot pump 16 High pressure Hydraulic line 17 Control valve 18A, 18B Inverter 19 Battery 21 Turning electric motor 22 Resolver 23 Mechanical brake 24 Turning speed reducer 25 Pilot line 26 Operating device 26A, 26B Lever 26C Pedal 27 Hydraulic line 28 Hydraulic line 29 Pressure sensor 30 Controller 31 Speed command Conversion unit 32 Drive control device 40 Turning drive control device 100 Buck-boost converter 101 Reactor 102A Boosting IGBT
102B IGBT for step-down
DESCRIPTION OF SYMBOLS 103 Power supply terminal 104 Output terminal 105 Capacitor 106 Battery voltage detection part 107 Battery current detection part 110 DC bus 111 DC bus voltage detection part 120 Motor 131 Capacity | capacitance 132 Internal resistance

Claims (4)

A lower traveling body,
An upper swing body mounted on the lower traveling body via a swing mechanism;
A boom mounted on the upper swing body;
A boom cylinder mounted on the upper swing body for driving the boom;
A main pump for supplying hydraulic pressure to the boom cylinder;
An engine connected to the main pump;
A motor generator connected to the engine and the main pump;
A battery for storing electric power generated by the motor generator via a converter ;
In a shovel comprising a controller for measuring the internal resistance of the capacitor,
The controller
During shovel work, based on the presence or absence of the operation of the operation device, it determines whether and said converter operation shovel rather free becomes inoperative state is in an idling state not driven,
Measuring the first current value and the first stored voltage value of the battery when the non-working state is determined;
Thereafter, when the storage device is energized, the second current value and the second storage voltage value of the storage device are measured,
Based on the current difference obtained by the second current value and the first current value and the voltage difference obtained by the second storage voltage value and the first storage voltage value, the internal resistance of the battery is An excavator characterized by calculating. The controller is
Sampling a plurality of current values and stored voltage values when the capacitor is energized,
The shovel according to claim 1, wherein a predetermined calculation is performed using the plurality of sampled current values and stored voltage values, and the second current value and the second stored voltage value are calculated.   The excavator according to claim 1 or 2, wherein the controller changes the charging rate of the battery according to the calculated internal resistance.   The excavator according to any one of claims 1 to 3, wherein the controller calculates the internal resistance while maintaining the engine speed at a constant speed during operation.

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