JP2013085426A - Electromotive drive control unit of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromotive drive control unit of a construction machine which protects electrical devices from thermal destruction even when an electric motor mounted thereon is operated so as to repeat the lock state and the rotation state in the construction machine where composed of various kinds of work machines which are equipped with a common inverter device.SOLUTION: An electromotive drive control unit of a construction machine includes: an electric motor 4 driving a driven body of the construction machine; an inverter device 12 controlling the electric motor; an operation device 13 inputting speed commands of the electric motor; and control means 10 outputting torque commands to the inverter device in accordance with the speed command of the operation device. The electromotive drive control unit of the construction machine further includes: a speed detector 14 detecting a speed signal of the electric motor; and the control means 10 outputting a torque command, which limits torque of the electric motor 4, to the inverter device 12 in a region where the speed signal from the speed detector is smaller than a preset speed.

Description

  The present invention relates to an electric drive control device for a construction machine, and more particularly to an electric drive control device for a construction machine that can protect thermal destruction of electric equipment.

  In trench excavation work and backfilling work using a construction machine having a revolving structure driven by an electric motor on the traveling body, the revolving body is turned and the working machine installed on the revolving body is used as a natural ground. The operation of pressing against is repeated. At this time, the electric motor that drives the revolving structure is forcibly stopped (hereinafter referred to as the locked state) by the resistance force (reaction force) received by the work implement from a natural ground or the like, so that the rotation state → the lock state → the rotation state → The locked state is repeated.

  When the electric motor is in a locked state, the rotation speed of the electric motor becomes almost zero, and the controller that gives a command to the inverter device using this as a feedback amount continues to output a signal for generating a large torque to the inverter device. Become. As a result, since a large current continues to flow through a specific switching element constituting the inverter device, there is a problem that the heat generation amount of the specific switching element increases.

  For such a problem, when it is determined that the motor is in the locked state or the determining means for determining whether the motor is in the locked state or the motor is in the locked state, the switching calculated up to the previous time Based on the temperature of the element, using the calculation formula for the lock state, the temperature of the current switching element is calculated sequentially, and if it is determined that the motor is in the rotating state, it has been calculated up to the previous time Based on the temperature of the switching element, the temperature calculation means for sequentially calculating the temperature of the current switching element using the calculation formula for the rotation state, and switching according to the temperature of the switching element calculated by the temperature calculation means Some have control means for performing control to thermally protect the element (for example, see Patent Document 1).

JP 2006-296112 A

  As a measure for protecting the thermal destruction of the switching element of the inverter device caused by the repetition of the stop and rotation of the electric motor described above, as disclosed in Patent Document 1, the switching element is thermally activated based on the temperature of the switching element. Although there is something to be protected, this conventional technology requires a lot of sensors, a calculation algorithm based on a lot of sensor information, and a control circuit having control logic to be attached to the inverter device in order to grasp the temperature of the switching element, etc. Don't be.

  In addition, when applying the above-mentioned conventional technology to various types of hybrid-type work machines such as construction machines, the control logic and control constants etc. of inverter devices installed in advance are changed according to the model and specifications of the work machine It is necessary to make adjustments, which hinders the common use of inverter devices, and improvements have been desired.

  The present invention has been made based on the above-described matters, and an object of the present invention is to provide an electric drive control device for a construction machine that can protect a thermal breakdown induced in an electric device while sharing an inverter device. It is to provide.

  In order to achieve the above object, the first invention is an electric motor that drives a driven body of a construction machine, an inverter device that controls the electric motor, and an operating device that inputs a speed command of the electric motor; An electric drive control device for a construction machine comprising a control means for outputting a torque command to the inverter device in response to a speed command from the operating device; a speed detector for detecting a speed signal of the electric motor; Control means for outputting a torque command for limiting the torque of the electric motor to the inverter device in a region where the speed signal from the speed detector is smaller than a preset speed.

  According to a second aspect of the invention, an electric motor that drives a construction machine, an inverter device that controls the electric motor, an operating device that inputs a speed command of the electric motor, and a speed command from the operating device. In a construction machine electric drive control device comprising a control means for outputting a torque command to the inverter device, a speed detector for detecting a speed signal of the electric motor, a speed command from the operating device, and the speed detector Speed control means for calculating a torque signal of the electric motor based on a speed signal from the speed detector, speed / torque calculation means for calculating a torque limit signal according to the speed signal from the speed detector, and the speed / torque The torque signal from the speed control means is limited based on the torque limit signal from the calculation means, and the speed signal from the speed detector is smaller than a preset speed. In There region, and the torque command to limit the torque signal and control means having a limiting means for outputting to the inverter device.

  Further, according to a third aspect, in the second aspect, the speed / torque calculating means converts the speed signal into a torque based on a current value for preventing thermal destruction due to a temperature rise of the switching element constituting the inverter device. And calculating a torque limit signal.

  According to a fourth aspect, in the second or third aspect, the information processing apparatus further includes a notification unit that outputs a signal for reporting a restriction state that restricts the torque signal from the restriction unit.

  Further, a fifth invention is characterized in that, in any one of the first to fourth inventions, the driven body is a turning body equipped with a front work machine.

  According to the present invention, since the host controller side such as the vehicle body controller restricts and controls the operation that causes the thermal destruction of the electric device, the electric device can be protected from the thermal destruction. In addition, since the host controller side such as a vehicle body controller controls, it is possible to share an inverter device or the like in a construction machine composed of various types of work machines. As a result, the equipment of the construction machine can be shared and productivity can be improved.

It is a side view showing a hydraulic excavator provided with one embodiment of an electric drive control device of a construction machine of the present invention. 1 is a schematic diagram of a swing drive control system for a hydraulic excavator provided with an embodiment of an electric drive control device for a construction machine according to the present invention. It is the schematic of the inverter apparatus which comprises one Embodiment of the electric drive control apparatus of the construction machine of this invention. It is a control block diagram which shows one Embodiment of the electric drive control apparatus of the construction machine of this invention. It is a characteristic view which shows an example of the target turning speed setting function in the controller which comprises one Embodiment of the electric drive control apparatus of the construction machine of this invention. It is a characteristic view which shows an example of the speed and torque calculation setting function in the controller which comprises one Embodiment of the electric drive control apparatus of the construction machine of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an electric drive control device for a construction machine according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing a hydraulic excavator provided with an embodiment of an electric drive control device for a construction machine according to the present invention, and FIG. 2 is a hydraulic pressure provided with an embodiment of an electric drive control device for a construction machine according to the present invention. FIG. 3 is a schematic view of an excavator turning drive control system, and FIG. 3 is a schematic view of an inverter device constituting an embodiment of an electric drive control device for a construction machine according to the present invention.

  In FIG. 1, the hydraulic excavator includes a traveling body 1, a revolving body 2 provided on the traveling body 1 so as to be able to swivel, and an articulated work machine 3.

  The traveling body 1 includes a pair of crawlers 1a and 1b, a crawler frame 1c and 1d (only one side is shown in FIG. 1), a pair of traveling hydraulic motors 1e and 1f that independently drive and control the crawlers 1a and 1b, and It consists of a speed reduction mechanism.

  The swing body 2 includes a swing frame 2a, an engine (not shown) as a prime mover provided on the swing frame 2a, a swing electric motor 4, and an electric double layer capacitor 11 connected to the swing electric motor 4 (FIG. 2). And a decelerating mechanism 5 that decelerates the rotation of the swing electric motor 4, and the driving force of the swing electric motor 4 is transmitted via the decelerating mechanism 5, and the revolving member 2 ( The turning frame 2a) is driven to turn.

  The revolving unit 2 is provided with an articulated working machine 3. The articulated work machine 3 includes a boom 6 provided at the front portion of the swing body 2, a boom cylinder 6 a for driving the boom 6, and a shaft 7 rotatably supported near the tip of the boom 6. The arm cylinder 7 a for driving the arm 7, the bucket 8 rotatably supported at the tip of the arm 7, the bucket cylinder 8 a for driving the bucket 8, and the like.

  A cab 9 is provided on the front side of the swing frame 2a of the swivel body. The cab 9 includes a turning operation device 13 (FIG. 2) and an operation monitoring monitor 15 (FIG. 2), which will be described later. Is arranged.

  Next, a system configuration of the electric device for the hydraulic excavator will be schematically described. As shown in FIG. 2, the electric system includes a capacitor 11 as a power storage device, a swing electric motor inverter 12 for driving the swing electric motor 4, and the like.

  The DC power from the capacitor 11 is boosted to a predetermined bus voltage by a chopper or the like (not shown), and is input to a swing electric motor inverter 12 for driving the swing electric motor 4. The turning electric motor 4 drives the turning body 2 via the speed reduction mechanism 5. The capacitor 11 is charged and discharged depending on the driving state of the swing electric motor 4 (whether it is powering or regenerating). The swing electric motor 4 is provided with a speed detector 14 for detecting the speed.

  As shown in FIG. 3, the swing electric motor inverter 12 for driving the swing electric motor 4 is configured by a bridge circuit including six switching elements 12a to 12f such as IGBTs. Further, the swing electric motor inverter 12 has an inverter control controller (not shown). The inverter control controller receives a torque command from the controller 10 and outputs a PWM signal to the swing electric motor inverter 12 according to the command. Output. The switching elements 12a to 12f receive a command from the inverter controller, repeat ON / OFF of the current, create a three-phase alternating current by changing the pulse width, and drive the swing electric motor 4 with the commanded torque. . Depending on the type of motor, a configuration of a switching element different from the inverter circuit shown in FIG. 3 may be used, and FIG. 3 is only an example.

  Returning to FIG. 2, the controller 10 inputs an operation amount signal from the turning operation device 13 and a speed signal of the turning electric motor 4 from the speed detector 14, which are target rotation speed signals of the turning electric motor 4. Using these signals and the like, a control command for the swing electric motor inverter 12 that is a drive device for driving the swing electric motor 4 is generated, and the swing drive control of the swing electric motor 4 that drives the swing body 2 is performed. At this time, in the extremely low speed region where the revolving structure 2 is assumed to be locked or the like, the controller 10 adds the torque limit value and calculates the above-described control command, so that the electric device can be protected from thermal destruction. When the torque is limited in the control command described above, a signal indicating that the torque is limited is output to the operation monitoring monitor 15 to notify the operator that the current driving state is in the torque limit state.

  Next, the configuration and operation of the controller 10 according to the present embodiment will be described with reference to FIGS. FIG. 4 is a control block diagram showing an embodiment of an electric drive control device for a construction machine according to the present invention, and FIG. 5 is a target turning in a controller constituting an embodiment of the electric drive control device for a construction machine according to the present invention. FIG. 6 is a characteristic diagram showing an example of a speed setting function, and FIG. 6 is a characteristic chart showing an example of a speed / torque calculation setting function in a controller constituting an embodiment of the electric drive control device for a construction machine according to the present invention. 4 to 6, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and the detailed description thereof is omitted.

  The controller 10 illustrated in FIG. 4 calculates an input unit to which an operation signal from the turning operation device 13 and a speed signal from the speed detector 14 are input, and a control command for controlling the rotation speed of the turning electric motor 4. And an output unit that determines whether torque is limited, an output unit that outputs the calculated control command to the inverter 12 for the swing electric motor that is the drive device, and outputs a signal during torque limitation to the operation monitoring monitor 15; The controller unit includes a storage unit that stores in advance setting values used in the unit.

  The calculation unit receives the operation signal from the turning operation device 13 as an input, and converts the target speed converter 16 that converts the electric speed of the turning electric motor, and the actual turning from the speed detector 14 from the target turning speed that is the output of the target speed converter 16. A subtractor 17 that subtracts the speed to calculate the deviation, a controller 18, an absolute value calculator 19 that calculates the absolute speed value, a speed / torque calculator 20, a polarity converter 21, and the swing electric motor 4. And a limiter 22 for limiting the upper limit of the torque in the forward direction and the reverse direction.

  An operation signal from the turning operation device 13 is input to the target speed converter 16, and a target speed characteristic of the turning electric motor 4 corresponding to this input is set in advance. This set value is determined so as to match the operation feeling of the operator, and is stored in the storage unit. Here, the output of the target speed converter 16 corresponds to the signal from the turning operation device 13, and as shown in FIG. Is set in advance so as to obtain an output signal that is a target turning speed corresponding to each input value. The output signal of the target speed converter 16 is input to one (+ side) of the subtractor 17.

  The subtractor 17 inputs the output signal of the target speed converter 16 to one (+ side), the speed signal from the speed detector 14 to the other (− side), and the input signal from the + side to the − side input signal. And a deviation signal, which is an output signal, is output to the controller 18.

  The controller 18 calculates a target torque signal commensurate with speed control based on the deviation signal that is an input signal. The output signal of the controller 18 is input to the signal input side of the limiter 22.

  The absolute value calculator 19 receives the speed signal from the speed detector 14, performs an operation for calculating the absolute value of the speed signal, and outputs the output speed absolute value to the speed / torque calculator 20. Here, it is assumed that the sign of the speed signal detected by the speed detector 14 is reversed when the turning body 2 turns right and when it turns left. For this reason, the absolute value calculator 19 converts the velocity signal into an absolute value in order to enable appropriate control in both the left and right turns of the revolving structure 2.

  The speed / torque calculator 20 receives an absolute value speed signal V that is an output signal of the absolute value calculator 19, and a limit characteristic of the torque T with respect to this input is preset. This setting value is calculated by converting the speed signal to torque based on the current value that prevents thermal destruction due to the temperature rise of the switching element, and it is an extremely low speed region in which the temperature rise is a concern due to drive concentration of the switching element The driving torque, which is an output value, is limited, and a characteristic that does not apply as the speed increases is set and stored in the storage unit. Here, the output of the speed / torque calculator 20 corresponds to the signal from the absolute value calculator 19, and the absolute value of the speed signal is input as shown in FIG. It is set in advance so as to obtain an output signal that is a torque command. In this embodiment, a 70% torque command is output at 2% or less of the maximum speed signal, a 100% torque command is output at 10% or more of the maximum speed signal, and the maximum speed is increased from 2% of the maximum speed signal. During 10% of the signal, a linearly interpolated torque command is output. The output signal of the speed / torque calculator 20 is input to the positive limit input of the limiter 22 and the polarity converter 21.

  The polarity converter 21 calculates a negative torque limit signal obtained by inverting the polarity of the torque limit signal of the speed / torque calculator 20 as an input signal. The output signal of the polarity converter 21 is input to the negative side limit input of the limiter 22.

  The limiter 22 inputs the torque signal, which is the output signal of the controller 18, as a signal input, the output signal of the speed / torque calculator 20 as a positive limit input, and the output signal of the polarity converter 21 as a negative limit input. doing. Then, each value of the positive limit input and the negative limit input is set as a limit value, and a torque signal having a value obtained by limiting the signal input value by each limit value is output from the Ao unit, and the value of the signal input is set to each limit value. In the case of being limited and output, the digital signal 22Do being limited is output from the Do unit. An output signal 22Ao from the Ao portion of the limiter 22 is output as a control command (torque command) to the swing electric motor inverter 12 that drives the swing electric motor 4. Further, the output signal 22Do from the Do portion of the limiter 22 is output to the operation monitoring monitor 15 in order to notify the operator that torque is being limited.

  Next, the operation in the embodiment of the electric drive control device for the construction machine of the present invention having the above-described configuration will be described with reference to the drawings.

  First, the case of the normal turning motion of the swing body 2 will be described. In FIG. 4, when the operator operates the turning operation device 13, an operation signal is input from the turning operation device 13, so the target speed converter 16 calculates a target turning speed. Further, the speed detection means 14 detects the actual turning speed of the turning body 2. The target turning speed from the target speed converter 16 and the actual turning speed from the speed detector 14 are input to the subtractor 17. The subtractor 17 calculates a deviation amount from the target value, that is, a deviation signal. Based on this deviation signal, the controller 18 calculates a target torque signal commensurate with speed control and outputs it to the limiter 22.

  On the other hand, the actual turning speed detected by the speed detection means 14 is input to the speed / torque calculator 20 via the absolute value calculator 19. The speed / torque calculator 20 converts the actual turning speed into torque, calculates a torque limit value, and outputs it to the limiter 22. The limiter 22 limits the torque signal from the controller 18 based on the limit value signal and outputs a control command (torque command) to the swing electric motor inverter 12 that drives the swing electric motor 4.

  The case where it starts from the state where the turning electric motor 4 is stopped will be specifically described. In a state where the turning electric motor 4 is stopped, the actual turning speed from the speed detecting means 14 is zero indicating a stopped state. This zero signal is input to the speed / torque calculator 20 via the speed absolute value calculator 19.

  The speed / torque calculator 20 calculates a torque limit value that is a current value that causes no problem even if the temperature rises due to uneven rotation speed of the swing electric motor 4. By outputting the torque limit value and the torque limit value in the reverse rotation direction calculated by the polarity converter 21 to the limit input of the limiter 22, the limiter 22 outputs a control command (torque command) to the swing electric motor inverter 12. ).

  By repeating such calculation at every control calculation cycle, the swing electric motor 4 starts to move and the actual swing speed of the swing body 2 is gradually increased. As the actual turning speed of the swing body 2 increases, the torque limit value from the speed / torque calculator 20 increases, and the torque limit in the limiter 22 is released. As a result, a normal turning operation that does not require protection from thermal destruction of the electric device can be obtained.

  On the other hand, an operation when the above-described turning pressing operation or the like is performed will be described. First, in the normal turning operation, the torque limit in the limiter 22 is released as described above. When the turning electric motor 4 enters the locked state due to the reaction force received from the ground and the like from such a rotating state, the actual turning speed from the speed detecting means 14 becomes zero indicating a stopped state. As a result, the speed / torque calculator 20 outputs to the limiter 22 a torque limit value that is a current value that causes no problem even if the temperature rises due to uneven rotation speed of the swing electric motor 4 in advance. The limiter 22 limits the control command (torque command) that takes the torque limit value from the speed torque calculator 20 and outputs it to the inverter 12 for the swing electric motor. Further, the limiter 22 outputs a torque limiting signal to the operation monitoring monitor 15 in the cab 9 to notify the operator that the limiting control is being executed.

  As a result, the controller 10 limits the continuation of the output of a signal for generating a large torque for the inverter 12 for the swing electric motor. As a result, it is possible to suppress an increase in the amount of heat generated by the switching element due to a large current continuing to flow through the specific switching element constituting the inverter 12 for the swing electric motor.

  Even when the swing electric motor 4 is locked by a reaction force received from a natural ground or the like, the construction machine can avoid the stop of the swing due to the torque reduction by operating the work machine 3 or the like to release the load. For example, if the work implement pressed against a natural ground or the like is raised, the load that locks the swing electric motor 4 is removed, and turning can be started even with a limited torque command. Therefore, the control for reducing the torque command of the swing electric motor 4 as in the present embodiment does not cause a major problem in the operation of the construction machine.

  However, it is necessary to notify the operator that such a state of torque reduction is due to control. This is to guide the operator to start the above-described turning load avoidance work. In the present embodiment, when the limiter 22 performs the limiting operation, a signal indicating that the torque is limited is output to the operation monitoring monitor 15 in the cab 9 to notify the operator that the control is being performed. This is effective in improving workability.

  According to the embodiment of the electric drive control device for the construction machine of the present invention described above, the operation that causes the thermal destruction of the electric device on the host controller side such as the vehicle body controller 10 is limited and controlled. Can be protected from. Further, since the host controller side such as the vehicle body controller 10 controls, it is possible to share the inverter device 12 and the like in a construction machine composed of various types of work machines. As a result, the equipment of the construction machine can be shared and productivity can be improved.

  In the embodiment of the present invention, a hydraulic excavator provided with the swing body 2 and the swing electric motor 4 has been described as an example, but the present invention is not limited to this. The present invention can be applied to all construction and work machines having an electric motor and an inverter.

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 3 Working machine 4 Turning electric motor 5 Reduction gear 6 Boom 7 Arm 8 Bucket 9 Operator room 10 Controller 11 Capacitor 12 Inverter 13 Turning operation device 14 Speed detection means 15 Monitoring monitor device 16 Target speed converter 17 Subtraction 18 Controller 19 Absolute value calculator 20 Speed / torque calculator 21 Polarity converter 22 Limiter

Claims (5)

An electric motor that drives a driven body of a construction machine, an inverter device that controls the electric motor, an operating device that inputs a speed command of the electric motor, and an inverter device that responds to a speed command from the operating device. In an electric drive control device for a construction machine comprising a control means for outputting a torque command,
A speed detector for detecting a speed signal of the electric motor;
Control means for outputting a torque command for limiting the torque of the electric motor to the inverter device in a region where a speed signal from the speed detector is smaller than a preset speed;
An electric drive control device for a construction machine. An electric motor that drives a construction machine, an inverter device that controls the electric motor, an operation device that inputs a speed command of the electric motor, and a torque command that is output to the inverter device in response to a speed command from the operation device An electric drive control device for a construction machine, comprising:
A speed detector for detecting a speed signal of the electric motor;
Based on a speed command from the operating device and a speed signal from the speed detector, speed control means for calculating a torque signal of the electric motor, and a torque limit signal is calculated according to the speed signal from the speed detector. The torque signal from the speed control means is limited based on the speed / torque calculation means to perform and the torque limit signal from the speed / torque calculation means, and the speed signal from the speed detector is smaller than a preset speed A control means having a limiting means for outputting a torque command for limiting the torque signal to the inverter device in a region;
An electric drive control device for a construction machine. The electric drive control device for a construction machine according to claim 2,
The speed / torque calculation means calculates a torque limit signal by converting a speed signal to torque based on a current value that prevents thermal destruction due to a temperature rise of a switching element that constitutes the inverter device. Electric drive control device. In the electric drive control device of the construction machine according to claim 2 or 3,
An electric drive control device for a construction machine, further comprising notification means for outputting a signal for notifying a restriction state for restricting the torque signal from the restriction means. In the electric drive control device for a construction machine according to any one of claims 1 to 4,
An electric drive control device for a construction machine, wherein the driven body is a turning body equipped with a front work machine.

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