JP2013160018A - Power supply system and power supply method for motor-driven hydraulic construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system and a power supply method for a motor-driven hydraulic construction machine, in which the motor-driven hydraulic construction machine can be operated by stably supplying power thereto even when the amount of power supplied is smaller than the amount of power consumed.SOLUTION: The amount of power which does not exceed the maximum amount of power to be supplied from a power supply source 20 is set as the maximum amount of power to be consumed by a hydraulic pump. Then, after the hydraulic pump is driven, the amount of power consumed by the hydraulic pump 18 when subjected to a load is found. When the amount of power consumed exceeds the set maximum amount of power supplied, horsepower reducing control of the hydraulic pump 18 is performed to suppress the amount of power to be consumed. When it still exceeds the set maximum amount of power supplied in spite of the horsepower reducing control, tilt control of the hydraulic pump 18 together with the horsepower reducing control is performed to further suppress the amount of power to be consumed. Thus, power can be stably supplied thereto even when the amount of power supplied is smaller than the amount of power consumed.

Description

  The present invention relates to an electric hydraulic construction machine including a hydraulic pump driven by an electric motor, and in particular, power feeding of an electric hydraulic construction machine that supplies electric power from a power generation source that is independent of the electric pump via a power cable. The present invention relates to a system and a power supply method.

  Conventionally, there is a method of driving a hydraulic pump by an electric motor (hereinafter referred to as an electric hydraulic construction machine) as a large-sized hydraulic excavator used for an open pit operation in a mine. Since this electric hydraulic construction machine is not equipped with an engine or a generator driven by this engine, in order to drive the installed electric motor, power supply equipment installed in advance at the work site is connected via a power cable. Need to be supplied.

  However, with such a fixed power supply method, not only is the movement range of the electric hydraulic construction machine limited by the length of the power cable, but it is completely used when power supply equipment is not installed at the work site in advance. There is a drawback that it cannot be done.

  For this reason, for example, in Patent Document 1 below, a mobile power supply source such as a cart or a dump truck equipped with a diesel engine and a generator driven by the diesel engine is pulled or followed by an electric hydraulic construction machine. Thus, a method has been proposed in which electricity generated by this mobile power supply source is supplied to an electric hydraulic construction machine via a power cable.

JP 2010-142050 A

  By the way, the mobile power supply method as shown in Patent Document 1 has an advantage that there is no restriction on the moving range and power can be supplied anywhere, but on the other hand, a sufficient amount of power is generated and supplied only by the mobile power supply source. Has a problem that a large engine and a generator are required, which increases costs.

  On the other hand, high power supply capacity is not necessary in the operating state where power consumption is low, such as moving electric hydraulic construction machines between work sites equipped with power supply facilities or temporarily evacuating during blasting work. A simple power supply that can supply only the required power is sufficient.

  In other words, it is necessary to generate and supply a large amount of power necessary for operating all hydraulic actuators during full-scale operation. If a simple small power source that is about 50% of the amount of power and can supply such power is used, a significant cost reduction can be achieved.

  However, in the case of a combination of an electric hydraulic construction machine with a large amount of power consumption and a simple power supply source with a smaller amount of power supply, the power consumption of the electric hydraulic construction machine is reduced due to an emergency or careless operation. If the power supply source increases and exceeds the maximum power supply amount, the load on the power supply source may increase, leading to unexpected behavior due to an overcurrent failure or engine stoppage.

  Therefore, the present invention has been devised to solve these problems, and its purpose is to stably supply electric power even when the power supply amount of the power supply source is lower than the power consumption amount. A power feeding system and a power feeding method for a new electric hydraulic construction machine capable of operating a hydraulic construction machine.

  In order to solve the above-described problems, a first invention is a power supply system that supplies electric power from a power supply source to an electric hydraulic construction machine equipped with a variable displacement hydraulic pump driven by an electric motor via a power cable. The power consumption setting means for setting the power amount not exceeding the maximum supply amount of the power supply source as the maximum power consumption amount of the hydraulic pump, and the power consumption is suppressed by reducing the hydraulic absorption horsepower of the hydraulic pump. And a controller that performs tilt control that suppresses power consumption by reducing the discharge flow rate of the hydraulic pump, and the controller obtains power consumption when a load is applied to the hydraulic pump. When the power consumption exceeds the maximum power consumption set by the power consumption setting means, the horsepower reduction control of the hydraulic pump is performed and the horsepower reduction control is performed. When exceeding the maximum power consumption amount set by the power setting means is an electric hydraulic construction machine power supply system which is characterized in that the tilting control of the hydraulic pump with the reduced horsepower control.

  According to such a configuration, when the power consumption of the hydraulic pump exceeds the preset maximum power consumption by operating an electric hydraulic construction machine or the like, the power consumption is reduced by controlling the horsepower reduction of the hydraulic pump. If the power consumption is not reduced below the maximum power consumption set by the horsepower reduction control, the tilt control of the hydraulic pump is performed to further control the power consumption. As a result, the amount of power consumed by the electric hydraulic construction machine does not greatly exceed the maximum amount of power supplied from the power supply source, so the maximum amount of power supplied from the power supply source is lower than the amount of power consumed by the electric hydraulic construction machine. However, the electric hydraulic construction machine can be operated by stably supplying electric power while making maximum use of the power supply capability of the electric power supply source.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first aspect further includes means for issuing a warning prompting to stop the operation for increasing the load of the hydraulic pump, and the warning means includes the consumption even if the controller performs the tilt control. The power supply system for an electric hydraulic construction machine is characterized in that the warning is issued when the maximum power consumption set by the power setting means is exceeded.

  According to such a configuration, even if the above-described control for suppressing power consumption is performed, if the maximum supply amount of the power supply source is exceeded, an operator operating the electric hydraulic construction machine is surely warned to that effect. (Notification) can be made.

  3rd invention is equipped with the composite operation invalidation means which invalidates the implementation which combined two or more operation which increases the load of the said hydraulic pump in 1st or 2nd invention, This composite operation invalidation When the controller performs the tilt control and the controller exceeds the maximum power consumption set by the power consumption setting means, any one or more of the two or more operations or all the operations Is a power supply system for an electric hydraulic construction machine.

  According to such a configuration, any one or more of the two or more operations or all of the operations can be forcibly invalidated, so that the power consumption amount on the electric hydraulic construction machine side is the maximum of the power supply source. The supply will not be greatly exceeded.

  In a fourth aspect based on the third aspect, the composite operation invalidating means sets priorities for two or more operations that increase the load of the hydraulic pump, and when invalidating each of the operations, An electric power supply system for an electric hydraulic construction machine, wherein each operation is invalidated based on a priority order. According to such a configuration, it is possible to invalidate operations in descending order of priority, so that operations with high priority can be ensured to the end.

  According to a fifth aspect of the present invention, there is provided a method of supplying electric power from an electric power supply source to an electric hydraulic construction machine equipped with a variable displacement hydraulic pump driven by an electric motor, the electric power supply source After driving the hydraulic pump after setting the amount of power not exceeding the maximum supply amount of the hydraulic pump as the maximum power consumption of the hydraulic pump, the amount of power consumed when the hydraulic pump is loaded is obtained, and the power consumption When the amount exceeds the set maximum power consumption, the power consumption is suppressed by performing the horsepower reduction control of the hydraulic pump, and even if the horsepower reduction control is performed, the power consumption exceeds the set maximum power consumption. In this case, the electric power feeding method for the electric hydraulic construction machine is characterized in that the power consumption is further suppressed by performing tilt control of the hydraulic pump together with the horsepower reduction control.

  According to such a method, similarly to the first invention, the power consumption amount on the electric hydraulic construction machine side does not greatly exceed the maximum supply amount of the power supply source. Even when the electric power consumption of the electric hydraulic construction machine is lower than that of the electric hydraulic construction machine, the electric hydraulic construction machine can be operated by stably supplying electric power while making maximum use of the power supply capability of the electric power supply source.

  According to the power supply system and the power supply method of the present invention, the power consumption amount on the electric hydraulic construction machine side does not exceed the power supply amount of the power supply source, so the power supply amount of the power supply source is higher than the power consumption amount. Even if it is low, the electric hydraulic construction machine can be operated by stably supplying electric power while making maximum use of the power supply capability of the power supply source.

1 is an overall view showing an embodiment of a power supply system 100 for an electric hydraulic construction machine 10 according to the present invention. It is a block diagram which shows the structure of the electric power feeding system 100 of the electric hydraulic construction machine 10 which concerns on this invention. It is a flowchart figure which shows the flow of a process by the controller 16d. It is a graph which shows the relationship between power consumption, each control, and a process.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings. 1 and 2 show an embodiment of a power feeding system 100 for an electric hydraulic construction machine according to the present invention. As shown in the figure, this power supply system 100 connects an electric hydraulic construction machine 10 and a power supply source 20 with a power cable 30, and electric power generated by the power supply source 20 is connected to the electric hydraulic construction via the power cable 30. The machine 10 is supplied.

  This electric hydraulic construction machine 10 is a large hydraulic excavator that performs, for example, open pit digging work, and the like. A vehicle body is constituted by the body 12. A front work machine 13 for performing excavation work and the like is provided on the front side of the upper swing body 12 constituting the vehicle body so as to be able to be raised and lowered.

  The upper swing body 12 has a structure in which a building cover 15 and an operator cab (cab) 16 on which an operator is boarded are provided on a swing frame 14 serving as a base. A counterweight (not shown) is provided at the rear end of the building cover 15. An electric motor 17, a hydraulic pump 18 (see FIG. 2) driven by the electric motor 17, and a front A control valve (not shown) for supplying and discharging pressure oil generated by the hydraulic pump 18 to hydraulic actuators such as the boom cylinder 13a, the arm cylinder 13b, and the bucket cylinder 13c of the work machine 13 is provided. The building cover 15 is also provided with a control panel 19 for controlling power feeding to the electric motor 17 and a controller 16d to be described later.

  In the cab 16, in addition to a seat (not shown) on which an operator is seated, a travel lever 16 a for operating the lower traveling body 11 as shown in FIG. And a control lever 16b for performing a turning operation of the upper turning body 12, a monitor 16c for displaying various information, a controller 16d, and an input device 16e are mainly provided.

  The controller 16d is composed of an information processing device such as an LSI. The controller 16d mainly receives operation signals from the traveling lever 16a and the control lever 16b, and controls the hydraulic pump 18 and the control according to a predetermined control program stored in a ROM or the like. A valve (not shown) or the like is controlled. The input device 16e is used by an operator to directly set and input an amount of power that does not exceed the maximum supply amount of the power supply source 20 as the maximum power consumption amount of the electric motor 17, and includes, for example, a keyboard, a touch panel, and an operation panel. .

  The electric motor 17 rotationally drives a rotating shaft by three-phase alternating current (AC) of several thousand volts and several tens to hundreds of amperes supplied via the control panel 19, and the rotating shaft is coupled via a coupling 17a. The connected hydraulic pump 18 is driven.

  On the other hand, the hydraulic pump 18 is a known variable displacement hydraulic pump capable of adjusting the discharge flow rate of the pressure oil, for example, adjusting the discharge flow rate by changing the plunger stroke while keeping the rotation speed constant by tilt control. It consists of a connecting rod type piston hydraulic pump. The hydraulic pump 18 includes a tilt control unit 18a controlled by the machine-side controller 16d, and the discharge flow rate of the pressure oil is increased or decreased by the tilt control by the tilt control unit 18a. It is adjustable.

  Further, a slip ring 19 a is provided on the turning shaft portion of the electric hydraulic construction machine 10. The slip ring 19a has a structure in which a cable C1 extending from the control panel 19 provided on the upper swing body 12 side and a cable C2 extending from the terminal box 11a are pivotably connected to avoid disconnection during turning. ing. Each of the cable C1 and the cable C2 is composed of three conductive wires T, S, R and a ground wire E for flowing a three-phase alternating current. As shown in FIG. 1, the terminal box 11 a is provided on the lower traveling body 11 side, and a connector portion provided at an end portion of the power cable 30 extending from the power supply source 20 side is detachable.

  The power supply source 20 mainly includes a self-propelled truck 21, a diesel engine 22 for power generation installed on the loading platform of the truck 21, a generator 23, a power supply side controller 24, and the like. The diesel engine 22 uses light oil or the like supplied from a fuel tank (not shown) as fuel, and the engine control such as the rotation speed is performed by an ECM (diesel engine control unit) (not shown). After the engine is started, the generator 23 connected to the output shaft via the coupling 22a is driven.

  The generator 23 is driven by the output of the diesel engine 22 and generates a three-phase alternating current (AC) of a predetermined voltage / predetermined current, for example, a high voltage / current of 100 to 123 amperes at 6600 volts, 50 Hz. ing. The other end of the power cable 30 is connected to the generator 23, and power is continuously supplied to the electric hydraulic construction machine 10 side via the power cable 30.

  Next, an example of a power feeding method by the power feeding system 100 according to the present invention having such a configuration will be described with reference mainly to the flowchart of FIG. FIG. 3 shows the flow of processing by the controller 16d. The controller 16d first turns on the power (after the engine is driven), and when a predetermined system check is completed, the controller 16d proceeds to the first step S100, and if there is a power consumption setting input, the controller 16d proceeds to the next step S102. The process proceeds to start the electric motor, and the process proceeds to the next step S104.

  That is, when operating the electric hydraulic construction machine 10, the operator grasps the maximum amount of power supplied from the power supply source 20, and inputs the amount of power not exceeding the maximum amount supplied from the input device 16e. 16d sets the numerical value input by the input device 16e as the maximum power consumption amount on the electric hydraulic construction machine 10 side. For example, the maximum current consumption amount is set in a range of 123 A where the load factor is 100% from 50 A (ampere) where the device can operate (operate). Note that the voltage (for example, 6600 V) and the frequency (for example, 50 Hz) are the same.

  In step S104, after the electric motor 17 is started, it is determined whether or not there is an operation input signal by operating the travel lever 16a, the control lever 16b, or the like. As a result, when it is determined that there is no operation input signal (NO), the process waits as it is, but when it is determined that there is an operation input signal (YES), the process proceeds to the next step S106.

  In step S106, it is determined whether or not the amount of power consumed by the operation exceeds the maximum power consumption set in step S100. When it is determined that the amount does not exceed (NO), the process returns to step S104. When it is determined (YES), the process proceeds to the next step S108.

  In step S108, it is determined whether or not the power consumption can be suppressed below the maximum power consumption set only by the horsepower reduction control of the pressure oil absorption horsepower by the hydraulic pump 18, and when it is determined that it can be suppressed (YES), step S110 is performed. When it is determined that the suppression is not possible only by the horsepower reduction control (NO), the process proceeds to step S112.

  In step S110, the horsepower reduction control is performed on the hydraulic pump 18 so as not to exceed the set maximum power consumption. For example, when the set maximum power consumption is 100A or more, it exceeds the maximum power consumption set in the range of 123A (load factor 100%) in the no control state to 100A (load factor 75%) which is the maximum control. After the horsepower reduction control is performed so as not to occur, the process returns to step S104.

  On the other hand, in step S112, since the power consumption cannot be reduced below the set power consumption amount only by the horsepower reduction control, the horsepower control is shifted to the next step S114 after the horsepower reduction control is maximized (for example, 100A: load factor 75%). 18 tilt control is performed. For example, when the set current consumption is 99 to 50 A, the horsepower reduction control is performed so as not to exceed the set power consumption in the range of 99 A (140 L / min) to 50 A (100 L / min), and then the process proceeds to step S114. Transition.

  In step S114, the power consumption is measured and the process proceeds to the next step S116. In step S116, it is determined whether or not the set power consumption is below the tilt control. As a result, when it is determined that the set power consumption is below (YES), the process returns to step S114. However, when it is determined that the set power consumption is not below the tilt control, the process proceeds to the next step S118 and 2 It is determined whether or not two or more operations are performed simultaneously. For example, it is determined whether or not the traveling operation by the traveling motor and the turning operation by the turning motor, or the operation of the front work machine 13 is performed together with these operations. As a result, when it is determined that the combined operation is not performed (NO), the process jumps to step S124, but when it is determined that the combined operation is performed (YES), the process proceeds to the next step S120.

  In step S120, the composite operation is invalidated to suppress the power consumption. In this invalidation process, it is desirable to set a priority order for each operation and invalidate based on the priority order. . For example, when (1) traveling operation> (2) turning operation> (3) front operation is set as the priority order at the time of composite operation input, the operation of the front work machine 13 which is the operation with the lowest priority is invalidated in order. The driving operation with the highest priority is not invalidated until the end.

  Then, in the next step S122, it is determined whether or not the power consumption amount has fallen below the set power consumption amount by the combined operation invalidation process. When it is determined that the power consumption amount has fallen below (YES), the process returns to step S114 and is determined not to fall below. If (NO), the process proceeds to the next step S124, an alarm is displayed on the monitor 16c in the cab, and the process proceeds to the next step S126.

  In step S126, as a result of the alarm display, it is determined whether all operations have been stopped and the operation input signal has been stopped. If it is determined that all operations have been stopped (YES), the alarm is stopped. Returning to step S104, if it is determined that all operations are not stopped even after a predetermined time has elapsed (NO), the process proceeds to step S128 to forcibly stop the electric motor 18 and the process is terminated.

  As described above, when the power consumption of the hydraulic pump 18 exceeds the preset maximum supply amount of the power supply source 20 by operating the electric hydraulic construction machine 10 or the like, the power feeding method of the present invention reduces the hydraulic pump 18. The power consumption is suppressed by performing horsepower control (step S108), and if the horsepower control does not fall below the maximum supply amount even by this horsepower reduction control, tilt control (step S112) of the hydraulic pump 18 is performed to further reduce the power consumption. Control to suppress is performed. As a result, the power consumption amount on the electric hydraulic construction machine 10 side does not greatly exceed the maximum supply amount of the power supply source 20, so the maximum supply amount of the power supply source 20 is the power consumption amount of the electric hydraulic construction machine 10. Even if it is lower than that, the electric hydraulic construction machine 10 can be operated by stably supplying electric power while making maximum use of the power supply capability of the power supply source 20.

  In addition, an alarm is displayed when the maximum supply amount of the power supply source 20 is exceeded even when control for suppressing power consumption such as tilt control and composite operation invalidation processing is performed. The operator who operates 10 can be surely warned (notified) to that effect, so that the operator can quickly take an appropriate response.

  In addition, when two or more operations for increasing the load of the hydraulic pump 18 are performed in combination, any one or more of the two or more operations or all of the operations can be forcibly invalidated. The power consumption amount on the hydraulic hydraulic construction machine 10 side does not greatly exceed the maximum supply amount of the power supply source 20.

  FIG. 4 shows the relationship between these controls and processes. As shown in the figure, when the set power consumption is the power consumption A, it can be achieved only by the horsepower reduction control, but in the case of the power consumption B, it is achieved by combining the tilting control with the tilt control. it can. Furthermore, in the case of the power consumption C, since it cannot be achieved even if the horsepower reduction control and the tilt control are performed together, it can be achieved by invalidating the combined operation when performing the combined operation. it can.

  Furthermore, in this composite operation invalidation processing, priority is set for two or more operations, and each operation is invalidated based on the priorities, so invalidation is performed in order from the operation with the lowest priority. It is possible to perform operations with high priority, such as traveling operations, until the end.

  As a result, the power consumption amount on the electric hydraulic construction machine 10 side does not exceed the power supply amount of the power supply source 20 over a long period of time, so the power supply amount of the power supply source 20 is lower than the power consumption amount. Even in this case, the electric hydraulic construction machine 10 can be operated by stably supplying electric power while maximally utilizing the power supply capability of the power supply source 20. That is, the maximum power consumption of the electric hydraulic construction machine 10 can be suppressed to the maximum power supply amount of the power supply source 20, and the electric hydraulic construction machine 10 due to sudden power loss due to overcurrent, engine stop, or the like. Inconveniences such as unexpected behavior can be avoided in advance.

  Further, if the operator is not aware of the alarm or ignores it as in step S126 of FIG. 3, if the process for forcibly stopping the electric motor 18 is performed after warning the operator, the error will be more reliably detected. It is possible to avoid unforeseen behavior due to current failure or engine stoppage.

DESCRIPTION OF SYMBOLS 100 ... Electric power feeding system 10 ... Electric hydraulic construction machine 11 ... Lower traveling body 12 ... Upper turning body 16a ... Traveling lever 16b ... Operation lever 16c ... Monitor (warning means)
16d ... Controller 16e ... Input device (power consumption setting means)
17 ... Electric motor 18 ... Hydraulic pump 20 ... Power supply source 22 ... Diesel engine 23 ... Generator 30 ... Power cable

Claims (5)

A power supply system that supplies electric power from an electric power supply source to an electric hydraulic construction machine equipped with a variable displacement hydraulic pump driven by an electric motor,
Power consumption setting means for setting the amount of power not exceeding the maximum supply amount of the power supply source as the maximum power consumption of the hydraulic pump;
A controller for reducing the power consumption by reducing the hydraulic absorption horsepower of the hydraulic pump, and a controller for performing tilt control for reducing the power consumption by reducing the discharge flow rate of the hydraulic pump;
The controller is
Obtain the power consumption when the hydraulic pump is loaded, and when the power consumption exceeds the maximum power consumption set by the power consumption setting means, perform the horsepower reduction control of the hydraulic pump,
An electric hydraulic construction machine that performs tilt control of the hydraulic pump together with the horsepower reduction control if the maximum power consumption set by the power consumption setting means is exceeded even after the horsepower reduction control is performed. Power supply system. Means for issuing a warning to stop the operation of increasing the load of the hydraulic pump;
2. The electric motor according to claim 1, wherein the warning unit performs the warning when the controller performs the tilt control and exceeds the maximum power consumption set by the power consumption setting unit. Power supply system for hydraulic construction machines. Comprising a composite operation invalidating means for invalidating the composite operation of two or more operations for increasing the load of the hydraulic pump;
The composite operation invalidating unit is configured to perform any one or more or all of the two or more operations when the maximum power consumption set by the power consumption setting unit is exceeded even when the tilt control is performed. The power feeding system for an electric hydraulic construction machine according to claim 1 or 2, wherein the operation is invalidated.   The combined operation invalidation means sets priority for two or more operations that increase the load of the hydraulic pump, and invalidates each operation based on the priority when invalidating each operation. The power feeding system for an electric hydraulic construction machine according to claim 3. A method for supplying electric power from a power supply source to an electric hydraulic construction machine equipped with a variable displacement hydraulic pump driven by an electric motor via a power cable,
The amount of power consumed by the hydraulic pump when a load is applied after the hydraulic pump is driven after setting the amount of power not exceeding the maximum amount of power supplied from the power supply source as the maximum amount of power consumed by the hydraulic pump. ,
When the power consumption of the hydraulic pump exceeds the set maximum power consumption, the power consumption is suppressed by performing a horsepower reduction control of the hydraulic pump,
If the set maximum power consumption is exceeded even after performing the horsepower reduction control, the electric power consumption is further suppressed by performing tilt control of the hydraulic pump together with the horsepower reduction control. Power supply method for hydraulic construction machines.

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