JP4979529B2 - Battery powered construction machinery - Google Patents

Description

  The present invention relates to a battery-driven construction machine that drives a plurality of actuators using a hydraulic pump that operates using a built-in battery as a drive source.

A battery-driven construction machine such as a power shovel (excavator) operates a hydraulic pump using a built-in battery as a driving source, and drives a boom cylinder, an arm cylinder, etc. using hydraulic pressure generated by the hydraulic pump. Combined with the absence of this problem, it is attracting attention as a low vibration / low noise machine suitable for use in urban areas (see, for example, Patent Documents 1 and 2).
Japanese Patent No. 3898775 Japanese Patent Laid-Open No. 10-159133

  By the way, in this type of battery-powered construction machine, the power capacity of the battery (built-in battery; vehicle-mounted battery) that can be mounted on the vehicle body is naturally limited, and currently it is continuously operated for a long time like an engine-driven construction machine. Difficult to do. Incidentally, commercial AC power sources that can be used in construction sites such as urban areas, particularly residential areas, are often of relatively small capacity that are temporarily laid for use in lighting, etc. It is also difficult to quickly charge the internal battery (vehicle battery). Furthermore, it is often difficult to bring a large-capacity power supply car equipped with a generator to this type of construction site.

  The present invention has been made in consideration of such circumstances, and its purpose is to be able to operate optimally according to the work environment at the construction site, and to effectively cut off the built-in battery (vehicle battery). It is an object of the present invention to provide a battery-powered construction machine that can cope with the above.

In order to achieve the above-described object, a battery-driven construction machine according to the present invention is configured to operate a hydraulic pump using a built-in battery as a driving source and to drive a plurality of actuators using hydraulic pressure generated by the hydraulic pump. And
In particular, a commercial power supply connector and an external battery connection connector, and an AC / DC converter for converting the commercial AC power input via the commercial power supply connector into a drive system for the hydraulic pump using the built-in battery. And a voltage regulator for converting a DC power input via the external battery connection connector and supplying the voltage to a drive system of the hydraulic pump by the built-in battery.

  Incidentally, the built-in battery is charged by the power supplied from the AC / DC converter to the hydraulic pump drive system and / or by the power supplied from the voltage regulator to the hydraulic pump drive system. It is preferable to provide it. As the electric motor for driving the hydraulic pump, for example, an AC type driven by an AC power source is used, and for the drive system of the electric motor, the AC power source is generated from the DC power source supplied from the built-in battery. What is necessary is just to comprise as an inverter provided.

  And in generating the AC power source that drives the electric motor using the inverter, the higher DC voltage supplied to the inverter is advantageous in terms of the power source efficiency. In the AC / DC converter, Generates a DC voltage of the voltage supplied to the inverter, and the voltage regulator is connected to <a> the voltage of the DC power input via the external battery connector and the DC power supplied from the built-in battery. A step-up circuit that boosts the voltage of the output to a voltage equivalent to the voltage of a DC power source that is converted by the AC / DC converter and supplied to the drive system of the hydraulic pump; and <b> the AC / DC converter And a step-down circuit that converts the voltage of the DC power source output from the DC power source and the voltage of the DC power source input via the external battery connector to the charging voltage of the built-in battery. What is necessary is just to comprise as a thing.

  In addition, a controller for detecting the input of commercial AC power via the commercial power connector, the input of DC power via the external battery connector, and the remaining charge of the built-in battery is provided. It is preferable that the power supply to the drive system of the hydraulic pump is selectively controlled according to the control. It is also preferable that the controller controls the operation of the hydraulic pump regulator in accordance with the detection result, thereby controlling the maximum rotational speed of the hydraulic pump.

  According to the battery-driven construction machine having the above-described configuration, since the commercial power supply connector and the external battery connection connector are provided, even if a situation occurs in which the remaining charge capacity of the built-in battery is insufficient (or the charge is exhausted) The hydraulic pump can be driven using a commercial AC power source fed via the commercial power source connector or using a DC power source supplied via an external battery connector. Accordingly, it is possible to continuously operate the battery-powered construction machine, and it is possible to avoid a situation in which the battery-powered construction machine becomes inoperable at the construction site due to the out-of-charge of the built-in battery.

  In addition, the built-in battery can be charged as appropriate using a commercial AC power source that is fed via the commercial power connector or using a DC power source that is supplied via the external battery connector. It becomes possible to prevent such a situation. Furthermore, since the voltage of the DC power supply is adjusted using a voltage regulator equipped with a booster circuit and a step-down circuit, an inverter that generates an AC power supply that drives the electric motor that is the drive source of the hydraulic pump is optimized for high power efficiency. Therefore, it is possible to stably drive with a direct current voltage, and to charge the built-in battery optimally.

Hereinafter, a battery-powered construction machine according to an embodiment of the present invention will be described with reference to the drawings, taking a small power shovel with a standard bucket capacity of about 0.16 m ³ as an example.
FIG. 1 shows a schematic configuration diagram of a power shovel according to this embodiment. The vehicle body 1 of the power shovel includes a traveling unit 1a and a turning unit 1b that is turnably provided on the traveling unit 1a, and a driver's seat is provided on the turning unit 1b. A blade 2 is provided at the front portion of the traveling portion 1a of the vehicle body 1 so as to be movable up and down, and a bucket 5 is rotatable in front of a driver seat of the turning portion 1b via a boom 3 and an arm 4. Is provided. These blade 2, boom 3, arm 4 and bucket 5 are each driven by a hydraulic cylinder which will be described later.

  In particular, this power shovel is of a battery drive type that uses electric power (DC power energy) stored in the built-in battery 6 mounted on the swivel unit 1b as a power source, and replaces the conventional general engine with the built-in battery 6 described above. The hydraulic pump described above is driven by the direct-current power obtained from the electric motor, and the boom cylinder, the boom cylinder, and the like are respectively driven by the hydraulic oil generated by the hydraulic pump. The traveling drive of the traveling unit 1a and the turning of the turning unit 1b are also performed using the hydraulic oil generated by the hydraulic pump.

Incidentally, the built-in battery 6 is composed of, for example, a secondary battery such as a lithium ion battery that obtains a rated output of 160 V _DC, and is mounted in the rear part of the driver seat of the turning unit 1b described above. Further, since the built-in battery 6 itself is a heavy object, it also serves as a weight balance body (counter weight) against a heavy load applied to the boom 3. A control panel 7 is provided above the built-in battery 6 mounted on the swivel unit 1b as described above, and a commercial power supply is connected to the control panel 7 as shown in FIG. A connector 8 and an external battery connection connector 9 are provided.

  Now, the control panel 7 responsible for driving the power shovel having the above-described configuration is constructed as shown in FIG. 3, for example. The hydraulic pump 11 that generates hydraulic oil for driving the hydraulic cylinder described above is driven by a three-phase drive type electric motor (three-phase induction motor) 12 having a rated output of about 22 kW, for example. The hydraulic oil generated by the hydraulic pump 11 driven by the electric motor 12 is supplied to the hydraulic cylinder described above via the control valve (C / V) 13, specifically, the boom cylinder 14 or the arm cylinder 15. , And supplied to the bucket cylinder 16 and the like. Needless to say, the operation of the control valve (C / V) 13 is controlled according to the amount of operation of an operation lever (not shown) in the driver's seat.

In order to drive such a motor 12 with the DC power energy stored in the built-in battery 6 described above, an inverter 21 is provided that converts the DC power into three-phase 200 V AC power. Specifically, the inverter 21 is configured to generate a three-phase 200V AC power by inputting a 300V DC voltage. The output voltage 160V _DC of the built-in battery 6 is supplied to the inverter 21 after being converted to 300V _DC via a step-up / down regulator (voltage regulator) 22 described later.

In addition, an AC / DC converter for converting a commercial three-phase AC power supply 200V fed from the outside through the commercial power supply connector 8 into a DC power of 300V DC is provided in the power supply line from the commercial power supply connector 8 described above. (AC / DC) 23 is provided, and 300 V _DC output from the AC / DC converter (AC / DC) 23 is also supplied to the inverter 21. The AC / DC converter (AC / DC) 23 converts the _AC power 100V _AC into 300V _DC when a single-phase 100V AC power is input via the commercial power supply connector 8. It also has a function to output. Switching of the operation mode of the AC / DC converter (AC / DC) 23 is performed by a controller 24 described later.

  Further, the power supply line from the external battery connection connector 9 is input to the step-up / step-down device 22 described above. Then, for example, DC power of 250V DC supplied from the external battery B through the external battery connector 9 is boosted and converted to DC 300V by the buck-boost 22 and supplied to the inverter 21 or to 160V DC. The voltage is step-down converted and supplied to the built-in battery 6. The step-up / step-down operation mode of the step-up / down converter 22 is also controlled by the controller 24 described later.

  Incidentally, for example, as shown in FIG. 4, the step-up / step-down device 22 includes a charging circuit 22a and a boosting circuit 22b, and selectively operates the charging circuit 22a and the boosting circuit 22b by switching and controlling a plurality of switches S1 to S5. Configured to let For example, as shown in FIG. 5, the charging circuit 22a switches the input DC voltage Vin through a switch element SW in series, and the DC power intermittently cut by this is connected to a filter composed of a coil L and a capacitor C. The output voltage Vout is stepped down by filtering (smoothing). Further, for example, as shown in FIG. 6, the booster circuit 22 b boosts the coil C by intermittently switching the resonance current generated between the coil L and the capacitor C by the input DC voltage Vin applied to the coil L by the switch element SW. The output voltage Vout is obtained.

By the way, this power shovel is basically configured to use the above-described built-in battery 6 as a drive source of the vehicle body circuit 25 including the control of the control valve (C / V) 13 and the control of the traveling system. ing. For this reason, the power output line (charge / discharge terminal) of the built-in battery 6 converts the DC power of 160V _DC output from the built-in battery 6 into a _DC voltage of 24V or 12V, which is the driving voltage of the vehicle body system. A direct current converter (DC / DC converter) 26 is provided.

Furthermore, in the input power line extending from the AC / DC converter 23 to the inverter 21, the DC / DC converter (DC) which converts the DC voltage 300V _DC into the vehicle body system driving voltage 24V _DC / 12V _DC described above. / DC converter) 27 is provided. This DC / DC converter (DC / DC converter) 27 is provided with AC power supplied from a commercial power source via the commercial power connector 8 or DC power supplied from an external battery via the external battery connector 9. Therefore, it plays a role of generating a drive voltage 24V _DC / 12V _DC of the vehicle body system. The direct-current voltages (vehicle body system voltages) 24V _DC / 12V _DC generated by the direct-current / direct-current converters (DC / DC converters) 26 and 27 are output via the diodes 26a and 27a, respectively. Electric power is supplied to the vehicle body circuit 25 without interference.

The controller 24 described above operates by receiving the DC voltage 24V _DC / 12V _DC of the vehicle body system when the key switch 28 is turned on, and is realized by, for example, a microcomputer. The controller 24 detects the charging voltage and charging / discharging current of the built-in battery 6 through the sensor 24a and monitors the remaining charge capacity, and uses the sensor 24b incorporated in the commercial power supply connector 8 to The power supply connector 8 is configured to detect the power supply from the external battery via the external battery connection connector 9 by using the sensor 24c incorporated in the external battery connection connector 9 with the commercial power supply. These sensors 24a, 24b, and 24c are composed of ammeters such as a voltmeter and a current transformer (CT), for example. Then, the controller 24 operates the above-described AC / DC converter (AC / DC) 23 and the step-up / down converter 22 according to the state information detected via each of the sensors 24a, 24b, 24c, and further the hydraulic pump 11 The operation of the regulator 29 that varies the driving conditions is controlled.

  FIG. 7 shows a schematic control procedure of the controller 24. That is, the controller 24 determines whether or not commercial AC power is supplied, for example, via the commercial power connector 8 (step S1). If commercial AC power is supplied, AC / DC is supplied. The converter (AC / DC) 23 is operated to drive the above-described electric motor 12 using the commercial AC power source as a drive source <Step S2>. At this time, it is determined whether or not the remaining charge capacity of the built-in battery 6 is sufficient <step S3>. If the remaining charge capacity is insufficient, the charging circuit 22a of the buck-boost 22 is operated to operate the commercial AC. The built-in battery 6 is charged using the power source <Step S4>. However, if the remaining charge capacity is sufficiently satisfied, the process returns as it is.

  On the other hand, when there is no supply of commercial power via the commercial power connector 8, it is determined whether or not there is power supply from the external battery via the external battery connector 9 <step S 5>. When power is supplied from the external battery, the above-described electric motor 12 is driven using the external battery as a drive source by operating the booster circuit 22a of the step-up / down converter 22 (step S6). Also in this case, it is determined whether or not the remaining charge capacity of the built-in battery 6 is sufficient <step S3>, and when the remaining charge capacity is insufficient, the charging circuit 22a of the step-up / down converter 22 is operated simultaneously. The built-in battery 6 is charged using the external battery <Step S4>. However, if the remaining charge capacity is sufficiently satisfied, the process returns as it is.

  On the other hand, when there is no power supply from the external battery via the external battery connection connector 9, it is determined whether or not the remaining charge capacity of the internal battery 6 is sufficient <step S7>. If the remaining charge capacity of the built-in battery 6 is sufficient, the above-described electric motor 12 is driven using the built-in battery 6 as a drive source by operating the booster circuit 22a of the step-up / step-down regulator 22 (step S8). If the remaining capacity of the internal battery 6 is insufficient, an alarm is issued to warn that the power shovel cannot be operated normally (step S9).

For simplicity, as shown in the control procedure of FIG. 8, it is determined whether or not commercial AC power is supplied via the commercial power connector 8 (step S11), and commercial AC power is supplied. If it is, the AC / DC converter (AC / DC) 23 is actuated to drive the above-described electric motor 12 using the commercial AC power source as a drive source (step S12). Next, it is determined whether or not the charging button (SW) 30 for the built-in battery 6 is turned on <step S13>. When the charging button 30 is turned on, the charging circuit 22a of the step-up / down booster 22 is activated, The built-in battery 6 may be charged using a commercial AC power source as a drive source (step S14).

On the other hand, when the commercial power is not supplied, it is determined whether or not there is power supply from the external battery via the external battery connector 9 (step S15). When power is supplied from the external battery, the booster circuit 22a of the step-up / down regulator 22 is operated to drive the above-described electric motor 12 using the external battery as a drive source (step S16). Also in this case, it is determined whether or not the above-described charging button 30 is turned on (step S17). When the charging button is turned on, the booster circuit 22a in the step-up / step-down booster 22 is deactivated in order to preferentially charge the built-in battery 6 (step S18). The built-in battery 6 is charged by operating the charging circuit 22b of the pressure device 22 (step S19).
If no commercial power is supplied and no power is supplied from the external battery B, the booster circuit 22a of the step-up / step-down device 22 is operated <Step S20>, and the power supplied from the built-in battery 6 is supplied. The electric motor 12 described above is used to drive.

  With the control procedure as described above, the controller 24 selectively sets the operation mode of the power shovel according to the connection state to the commercial power supply connector 8 and the external battery connection connector 9 and the charge state of the internal battery 6, The operation mode is optimized according to the environment of the construction work site. Specifically, the controller 24 controls the operation of the charging circuit 22a and the boosting circuit 22b while switching the switches S1 to S5 of the step-up / down converter 22 as shown in FIG. 9 and simultaneously controls the charging / discharging of the built-in battery 6. Then, the drive source of the electric motor 12 is switched.

  That is, when the hydraulic pump 11 (electric motor 12) is driven using a commercial power source fed via the commercial power connector 8, the built-in battery 6 is turned off by turning off all of the switches S1 to S5 of the buck-boost 22. Disconnect and drive the excavator. However, when the built-in battery 6 needs to be charged, the switches S1 and S3 are turned on, and the DC power obtained from the AC power source through the AC / DC converter (AC / DC) 23 is supplied to the charging circuit 22a. The internal battery 6 is charged by the output of the charging circuit 22a.

  When driving the hydraulic pump 11 (electric motor 12) using the built-in battery 6, the switch S4 is turned on, and the DC voltage obtained from the built-in battery 6 is boosted via the boost circuit 22b and applied to the inverter 21. Further, when the internal battery 6 is charged by the external battery B connected to the external battery connector 9, the stitches S3 and S5 may be turned on to form a charging path for the internal battery 6 via the charging circuit 22a. When the hydraulic pump 11 (electric motor 12) is driven using the external battery B, the stitches S2 and S5 are turned on, and the DC voltage supplied from the external battery B is boosted via the booster circuit 22b. 21 may be added. If the built-in battery 6 is out of order, the switches S4 and S5 are turned off so that the built-in battery 6 is disconnected from the controller 24 of the vehicle body circuit 25 and the like.

  Thus, according to the power shovel configured as described above, although it is a battery-driven construction machine that operates the hydraulic pump 11 using the built-in battery 6 mounted on the vehicle body 1 as a drive source, the commercial power supply connector 8 and the external A battery connection connector 9 is provided, and the electric motor 12 and eventually the hydraulic pump 11 are driven using a commercial AC power source fed from a commercial power source connected to the commercial power source connection connector 8, and the external battery connection connector 9 Since the electric motor 12 is driven by the external battery B connected to the battery, even if the remaining charge capacity of the built-in battery 6 is insufficient or the built-in battery 6 is broken, By supplying power from the outside via the power supply connector 8 or the external battery connector 9, the power Yoberu (construction machine) can be operated. Therefore, it is possible to effectively avoid the problem that the power shovel (construction machine) is stuck at the construction site due to the problem of the built-in battery 6.

  When the remaining charge capacity of the built-in battery 6 is reduced, it is connected to the external battery connection connector 9 using a commercial AC power source fed from a commercial power source connected to the commercial power source connection connector 8. Since the built-in battery 6 can be easily charged using DC power fed from the external battery B, the shortage of charging of the built-in battery 6 can be easily solved. Further, the AC / DC converter 23 is used to convert the commercial AC power source into DC power to drive the electric motor 12, and the DC motor supplied from the built-in battery 6 or the external battery B is converted into voltage to convert the electric motor. 12 is configured to drive the electric motor 12, for example, by setting the voltage required for driving the electric motor 12 high, the electric motor 12 can be driven efficiently while keeping power conversion loss low. The effect of.

In particular, according to the embodiment described above, the charging voltage of the built-in battery 6 is increased to 160 V _DC , so that the charging efficiency is higher than when using a battery for a general vehicle body voltage of 24 V _DC / 12 V _DC. It is easy to increase the capacity of the internal battery 6 accordingly. Further, the DC voltage supplied from the external battery B is set to 250 V _DC and higher than the voltage 160 V _DC of the built-in battery 6, and further, the DC voltage generated from the commercial AC power supply is set to 300 V _DC which is higher. The built-in battery 6 can be easily charged simply by adjusting the voltage with the above-described step-up / down converter 22.

  By the way, in the power shovel (construction machine) according to the present invention, the operation condition of the hydraulic pump 11 is changed and set by the regulator 29 described above in order to realize the optimum operation according to the characteristics of the three kinds of power sources. It is configured to be possible. That is, when using a commercial AC power source fed via the commercial power connector 8, the operation of the inverter 21 is controlled so that the rotational speed of the hydraulic pump 11 can be varied up to the maximum rotational speed, and the hydraulic pressure The regulator 29 is controlled so that the output of the pump 11 can take the maximum value. With such a condition setting, the hydraulic pump 11 is operated with a so-called maximum output characteristic as shown by a characteristic curve a as shown in FIG. 10 for example in the pressure / flow rate characteristic (PQ characteristic) of the hydraulic pump 11. It will be.

  On the other hand, when the hydraulic pump 11 is driven using the built-in battery 6, the energy capacity is limited. Accordingly, in this case, for example, by suppressing the maximum tilt of the hydraulic pump 11 so that the hydraulic pump 11 can be driven by the built-in battery 6 for a long time, the rotational speed thereof is suppressed low, and thereby the characteristic curve b The output characteristics are changed as shown in FIG. As a result, the maximum load of the hydraulic pump 11 can be suppressed, and so-called power saving operation can be performed. And it becomes possible to extend the operating time of the internal battery 6 to the maximum. Note that when the external battery B connected to the external battery connector 9 is used, the operation characteristics of the hydraulic pump 11 may be variably set according to the specifications of the external battery B. By using such control in combination, it is possible to efficiently operate the power shovel (construction machine).

  The present invention is not limited to the embodiment described above. For example, the voltage value of the direct voltage described above may be set according to the specifications of the battery or the hydraulic pump. Although a small power shovel has been described here as an example, the present invention can be similarly applied to other battery-powered construction machines. As for charging of the internal battery 6, it is sufficient to charge the internal battery 6 using a commercial power source or the external battery B when the power shovel (construction machine) is stopped. Further, in a work site where it is difficult to operate the power shovel (construction machine) with the commercial power source or the external battery B connected to the power shovel (construction machine), for example, the built-in battery 6 is used as a power source and the power saving mode is set. After driving for a predetermined time, charging / discharging may be controlled so that the built-in battery 6 is rapidly recharged using abundant power from a commercial power source or the external battery B during a break time or the like. In addition, the present invention can be implemented with various modifications without departing from the spirit of the present invention.

The figure which shows the schematic external appearance structure of the power shovel which is one Embodiment of the battery drive construction machine which concerns on this invention. The figure which shows the structure of the back part of the power shovel shown in FIG. FIG. 2 is a block diagram of a power supply system of the power shovel shown in FIG. 1. The figure which shows the structural example of the buck-boost in the power supply system shown in FIG. The figure which shows the structural example of a charging circuit. The figure which shows the structural example of a booster circuit. The figure which shows the example of the switching control procedure of a power supply. The figure which shows another example of the switching control procedure of a power supply. The figure which shows the example of a switching of an operation mode. The figure which shows the change of the pressure and flow characteristic (PQ characteristic) at the time of changing the control characteristic of a hydraulic pump according to a power supply.

Explanation of symbols

6 Built-in battery 8 Commercial power connector 9 External battery connector 11 Hydraulic pump 12 Electric motor 21 Inverter 22 Booster / Booster (Voltage regulator)
23 AC / DC converter 24 Controller 26, 27 DC / DC converter

Claims (5)

An oil pressure pump is operated, a battery-powered construction machine for driving a plurality of actuators using the hydraulic pressure generated in the hydraulic pump,
An internal battery;
A commercial power supply connector to which a commercial AC power supply is connected ;
An external battery connector to which an external battery is connected ;
An AC-DC converter for DC converts AC power input through the commercial power supply connector,
A charging circuit that charges the built-in battery with DC power supplied from the AC / DC converter or the external battery connector;
A controller for detecting AC power input through the commercial power supply connector, DC power input through the external battery connection connector, and a remaining charge capacity of the built-in battery;
A charge switch capable of detecting ON / OFF by the controller,
The controller supplies direct-current power from the built-in battery to the drive system of the hydraulic pump when there is no input of alternating-current power through the commercial power supply connector and direct-current power through the external battery connection connector. And
There is either an input of AC power via the commercial power supply connector or an input of DC power via the external battery connector, and when the charge switch is ON, the DC power according to the remaining charge capacity of the built-in battery Charging the built-in battery, and when the charging switch is OFF, includes means for controlling to supply DC power to the hydraulic pump drive system from the AC / DC converter or the external battery connector. Battery-powered construction machine characterized by The hydraulic pump is driven by AC power ,
The drive system of the hydraulic pump is battery powered construction machine according to claim 1 in which comprises an inverter and the electric motor generates AC power from the dc power. A voltage regulator for converting DC power input via the external battery connector;
The voltage regulator, the voltage of the DC power supplied from the voltage and the internal battery of the DC power input through the external battery connector, said hydraulic pump being converted by the AC-DC converter A booster circuit that boosts the voltage to the same level as the voltage of the DC power supplied to the drive system;
The voltage of the DC power input through the DC power voltage and the external battery connector output from the AC-DC converter, in which a step-down circuit for converting the charging voltage of the internal battery The battery-powered construction machine according to claim 1 or 2 . The battery-driven construction machine according to claim 3, wherein the charging circuit and the booster circuit are provided with a changeover switch capable of disconnecting the built-in battery from the charging circuit and the booster circuit. Said controller, the input of the AC power through the commercial power supply connector, wherein the input direct-current power via the external battery connector, and in accordance with the detection result of the residual capacity of the internal battery, controls the operation of the hydraulic pump regulator The battery-powered construction machine according to any one of claims 1 to 4 , further comprising a function of controlling a maximum rotation speed of the hydraulic pump.

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