JP5436900B2 - Hybrid construction machine - Google Patents

Description

  The present invention relates to a hybrid construction machine.

  Conventionally, a hybrid construction machine in which a part of the drive mechanism is motorized has been proposed. Such a work machine includes a hydraulic pump for hydraulically driving movable parts such as a boom, an arm, and a bucket, and an AC motor (motor generator) is connected to an engine for driving the hydraulic pump. In addition to assisting the driving force of the engine, electric power obtained by power generation is charged in a storage battery (battery).

  In addition to the hydraulic motor as a power source for turning the upper swing body, an AC electric motor is provided, assisting the drive of the hydraulic motor with the AC motor during acceleration turning, and performing regenerative operation with the AC motor during deceleration turning to generate electric power. The battery is charged with electric power (see, for example, Patent Document 1).

JP-A-10-103112

  Since the motor generator, the AC motor for turning, and the drive control device (inverter or the like) that controls the drive of these devices generate heat due to the power consumption during operation, the hybrid construction machine uses these devices. A cooling mechanism for cooling is provided. Furthermore, in order to prevent burning of these devices due to temperature abnormality, the drive control device or the like has a configuration for stopping the operation when the drive control device or the like reaches a temperature equal to or higher than a threshold value. On the other hand, in a site where construction machinery is used, it is preferable that continuous operation is possible in order to improve work efficiency. If the drive control device or the like stops due to temperature rise, continuous operation becomes impossible, leading to a reduction in work efficiency.

  This invention is made | formed in view of the above problem, and it aims at providing the hybrid type construction machine which can improve work efficiency by implement | achieving continuous operation.

In order to solve the above problems, a hybrid construction machine according to the present invention cools an AC motor for driving a working element, a first drive control means for driving and controlling the AC motor, and a first drive control means. And a controller for controlling the first drive control means, wherein the first drive control means has a temperature of the first drive control means. When it is detected that the temperature is equal to or higher than a predetermined operation stop temperature, the controller has a mechanism that stops supplying the current for driving the AC motor and stops the operation of the first drive control means. When the refrigerant temperature acquired from the detection means is higher than the predetermined output suppression temperature, the upper limit value of the current supplied to the AC motor is made smaller than when the refrigerant temperature is equal to or lower than the output suppression temperature. It controls the first driving control means, output suppression temperature is characterized by lower than the shutdown temperature.

  In the hybrid type construction machine of the present invention, when the temperature of the refrigerant for cooling the first drive control means becomes equal to or higher than the output suppression temperature, the upper limit value of the current supplied to the AC motor is reduced. The temperature rise in the first drive control means is suppressed. Since the output suppression temperature is lower than the operation stop temperature, the first drive control means supplies the AC motor to the AC motor before the first drive control means starts the operation of the mechanism for stopping the supply of current to the AC motor. Control for reducing the upper limit value of the current is performed by the controller. Thereby, the stop by the temperature abnormality of an AC motor is prevented, and the continuous operation of a hybrid construction machine is implement | achieved.

  In the hybrid type construction machine, the controller controls the drive control means to reduce the upper limit value of the current supplied to the AC motor by limiting the upper limit value of the torque generated in the AC motor. And In this case, the upper limit value of the current supplied to the AC motor can be appropriately controlled by limiting the upper limit value of the torque.

  The hybrid construction machine includes a motor generator connected to the internal combustion engine and second drive control means for driving and controlling the motor generator, and the cooling device includes first and second drive control means. The controller controls the first and second drive control means, and when the refrigerant temperature acquired from the temperature detection means is greater than a predetermined output suppression temperature, the refrigerant temperature is equal to or lower than the output suppression temperature. Compared to the case, the first and second drive control means are controlled so as to reduce the upper limit value of the current supplied to the AC motor and the motor generator. In this case, the controller performs the control of the first drive control means and the second drive control means so as to reduce the upper limit value of the current supplied to each of the AC motor and the motor generator. It is possible to prevent the AC motor and the motor generator from being stopped due to a temperature rise.

  According to the present invention, it is possible to provide a hybrid construction machine capable of improving work efficiency by realizing continuous operation.

It is a perspective view which shows the external appearance of an excavator as an example of the working machine which concerns on this invention. It is a block diagram which shows internal structures, such as an electric system of a shovel, and a hydraulic system. It is a schematic block diagram which shows the structure of an inverter. It is a figure which shows an example of piping of the cooling water in the cooling device with which an shovel is provided. It is a schematic block diagram which shows the structure of a controller. It is a block diagram which shows the structure of an inverter control part. It is a flowchart which shows the processing content implemented in a controller. It is a figure which shows the torque at the time of control implementation of the inverter in this embodiment, the turning speed of a turning body, and the rotational speed of the electric motor for turning.

  An embodiment of a hybrid work machine of the present invention will be described with reference to the drawings. In the description of the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing an external appearance of an excavator 1 as an example of a hybrid construction machine according to the present invention. As shown in FIG. 1, the excavator 1 includes a traveling mechanism 2 including an endless track, and a revolving body 4 that is rotatably mounted on the upper portion of the traveling mechanism 2 via a revolving mechanism 3. The revolving body 4 is attached with a boom 5, an arm 6 linked to the tip of the boom 5, and a bucket 10 linked to the tip of the arm 6. The bucket 10 is a facility for attracting and capturing a suspended load G such as a steel material by a magnetic force. The boom 5, the arm 6, and the bucket 10 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. Further, the revolving body 4 is provided with a power source such as a driver's cab 4a for accommodating an operator who operates the position of the bucket 10, excitation operation and release operation, and an engine 11 for generating hydraulic pressure. The engine 11 is composed of, for example, a diesel engine.

  FIG. 2 is a block diagram showing an internal configuration such as an electric system and a hydraulic system of the excavator 1 of the present embodiment. In FIG. 2, the mechanical power transmission system is indicated by a double line, the hydraulic system is indicated by a thick solid line, the steering system is indicated by a broken line, and the electrical system is indicated by a thin solid line.

  As shown in FIG. 2, the excavator 1 includes a motor generator 12 and a speed reducer 13, and the rotation shafts of the engine 11 and the motor generator 12 are connected to each other by being connected to the input shaft of the speed reducer 13. Has been. When the load of the engine 11 is large, the motor generator 12 assists (assists) the driving force of the engine 11 with its own driving force, and the driving force of the motor generator 12 passes through the output shaft of the speed reducer 13 to the main pump 14. Communicated. On the other hand, when the load on the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 via the speed reducer 13, so that the motor generator 12 generates power. The motor generator 12 is configured by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. Switching between driving and power generation of the motor generator 12 is performed according to the load of the engine 11 and the like by the controller 30 that controls the drive of the electric system in the excavator 1.

  A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13, and a control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16. The control valve 17 is a device that controls the hydraulic system in the excavator 1. In addition to the hydraulic motors 2A and 2B for driving the traveling mechanism 2 shown in FIG. 1, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 are connected to the control valve 17 via a high pressure hydraulic line. The control valve 17 controls the hydraulic pressure supplied to them according to the operation input of the driver.

  An output terminal of an inverter 18A (second drive control means) is connected to an electrical terminal of the motor generator 12. The power storage means 100 is connected to the input terminal of the inverter 18A. The power storage means 100 includes, for example, a battery that is a storage battery, a step-up / down converter that controls charging / discharging of the battery, and a DC bus including positive and negative DC wirings (not shown). Here, the DC bus constitutes a constant voltage power storage unit, and the battery constitutes a variable voltage power storage unit. That is, the input end of the inverter 18A is connected to the input end of the step-up / down converter via the DC bus. A battery is connected to the output terminal of the buck-boost converter.

  The inverter 18 </ b> A controls the operation of the motor generator 12 based on a command from the controller 30. That is, when the inverter 18A causes the motor generator 12 to perform a power running operation, necessary power is supplied from the battery and the step-up / down converter to the motor generator via the DC bus. When the motor generator 12 is regeneratively operated, the battery is charged with the electric power generated by the motor generator 12 via the DC bus and the step-up / down converter. The switching control between the step-up / step-down converter and the step-down operation is performed by the controller 30 based on the DC bus voltage value, the battery voltage value, and the battery current value. As a result, the DC bus can be maintained in a state of being stored at a predetermined constant voltage value.

  Boom regeneration generator 300 is connected to power storage means 100 via inverter 18B. A hydraulic motor 310 is connected to the boom cylinder 7, and the rotating shaft of the boom regeneration generator 300 is driven by the hydraulic motor 310. The boom regeneration generator 300 is an electric work element that converts potential energy into electrical energy when the boom 5 is lowered by the action of gravity.

  The hydraulic motor 310 is configured to be rotated by oil discharged from the boom cylinder 7 when the boom 5 is lowered, and is provided to convert energy when the boom 5 is lowered according to gravity into rotational force. It has been. The hydraulic motor 310 is provided in the hydraulic pipe 7 </ b> A between the control valve 17 and the boom cylinder 7. The electric power generated by the boom regenerative generator 300 is supplied as regenerative energy to the power storage means 100 via the inverter 18B.

  Furthermore, a turning electric motor 21 as a working electric motor is connected to the power storage means 100 via an inverter 18C (first drive control means). The turning electric motor 21 is a power source of the turning mechanism 3 for turning the turning body 4. A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21.

  When the turning electric motor 21 performs a power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the turning speed reducer 24, and the turning body 4 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the swing body 4, the rotation speed is increased by the swing speed reducer 24 and transmitted to the swing electric motor 21 to generate regenerative power. The turning electric motor 21 is AC driven by an inverter 18C by a PWM (Pulse Width Modulation) control signal. As the turning electric motor 21, for example, a magnet-embedded IPM motor is suitable.

  The resolver 22 is a sensor that detects the rotation position and rotation angle of the rotation shaft 21A of the turning electric motor 21, and mechanically connects to the turning electric motor 21 to detect the rotation angle and rotation direction of the rotation shaft 21A. When the resolver 22 detects the rotation angle of the rotation shaft 21A, the rotation angle and the rotation direction of the turning mechanism 3 are derived. The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21 </ b> A of the turning electric motor 21 according to a command from the controller 30. The turning speed reducer 24 is a speed reducer that reduces the rotational speed of the rotating shaft 21 </ b> A of the turning electric motor 21 and mechanically transmits it to the turning mechanism 3.

  An operation device 26 (operation means) is connected to the pilot pump 15 via a pilot line 25. The operating device 26 is an operating device for operating the turning electric motor 21, the traveling mechanism 2, the boom 5, the arm 6, and the bucket 10, and is operated by an operator. A control valve 17 is connected to the operating device 26 via a hydraulic line 27, and a pressure sensor 29 is connected via a hydraulic line 28. The operating device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into a hydraulic pressure (secondary hydraulic pressure) corresponding to the operation amount of the operator and outputs the hydraulic pressure. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27 and detected by the pressure sensor 29.

  When an operation for turning the turning mechanism 3 is input to the operating device 26, the pressure sensor 29 detects this operation amount as a change in the oil pressure in the hydraulic line 28. The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28. This electric signal is input to the controller 30 and used for driving control of the turning electric motor 21.

  The controller 30 is configured by an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory. The controller 30 receives operation inputs from various sensors, the operation device 26, and the like, and performs drive control of the inverters 18A, 18B, 18C, the power storage means 100, and the like.

  Next, the inverter 18 will be described with reference to FIG. FIG. 3 is a schematic configuration diagram showing the configuration of the inverter 18.

  The inverter 18 is controlled by a PWM signal from the controller 30, and generates and outputs a motor drive signal for driving a motor such as the turning electric motor 21. Inside the inverter 18, an intelligent power module (IPM) 18a incorporating a transistor that constitutes the circuit of the inverter is configured. The IPM 18a is equipped with various sensors 18b such as a temperature sensor. The various sensors 18b detect events such as overcurrent, control power supply voltage drop, output short circuit, and temperature abnormality, and when these events are detected, output an IPM error signal. Here, the temperature abnormality event means that the temperature of the inverter 18 has become equal to or higher than a predetermined operation stop temperature TIh. The operation stop temperature is set to 100 ° C., for example. When the IPM 18a detects the IPM error signal, the IPM 18a stops supplying the current for driving the motor to be driven in order to prevent the motor to be driven and the inverter 18 from being burned out. In this case, the operation of the excavator 1 is also stopped and the continuous operation is interrupted.

  Next, the cooling device provided in the excavator 1 will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of cooling water piping in the cooling device.

  As shown in FIG. 4, the cooling device includes a tank 400, a pump 401, a pump motor 402, a radiator 403, and a water temperature gauge 404 (temperature detection means). Cooling water (refrigerant) in the cooling device is stored in the tank 400 and is sent to the radiator 403 by a pump 401 driven by a pump motor 402. The cooling water cooled by the radiator 403 is sent to the inverters 18 </ b> A, 18 </ b> B, 18 </ b> C, the step-up / down converter 102, and the battery 101 via the controller 30 by piping. The cooling water is further returned to the tank 400 via the turning electric motor 21, the motor generator 12, and the speed reducer 13. The water temperature gauge 404 detects the temperature of the cooling water sent from the radiator 403 and sends information related to the detected temperature to the controller 30.

  The cooling water piping to the controller 30 is directly connected to the radiator 403. Thereby, since the cooling performance with respect to CPU in the controller 30 can be ensured, the reliability of the shovel 1 is ensured. In FIG. 4, piping is connected so that the cooling water used for cooling the controller 30 is used for cooling the inverters 18 </ b> A to 18 </ b> C, the buck-boost converter 102, etc., but the piping from the radiator 403 is connected to the controller 30, the inverter It is good also as connecting 18A-18C, the buck-boost converter 102, etc. in parallel.

  Next, the controller 30 will be described with reference to FIG. FIG. 5 is a schematic configuration diagram showing a functional configuration of the controller 30.

  As shown in FIG. 5, the controller 30 includes an overall control unit 30D and inverter control units 30A, 30B, and 30C. The overall control unit 30D is a part that performs overall control of each component included in the excavator 1, and sends various information such as a speed command and a torque limit value to the inverter control units 30A, 30B, and 30C. Further, the overall control unit 30D acquires information related to the temperature of the cooling water sent from the water temperature gauge 404.

  The torque limit value sent from the overall control unit 30D to the inverter control units 30A, 30B, and 30C is the current supplied from the inverters 18A, 18B, and 18C to the motor generator 12, the boom regeneration generator 300, and the turning motor 21. Used to set the upper limit of. That is, the overall control unit 30D determines that the cooling water temperature T acquired from the water temperature gauge 404 is equal to or higher than the predetermined output suppression temperature Tth as compared to the case where the cooling water temperature T is lower than the output suppression temperature Tth. The inverters 18A, 18B, and 18C are controlled so as to reduce the upper limit value of the current supplied to the motor generator 12, the boom regeneration generator 300, and the turning motor 21. Here, since the cooling water needs to maintain the cooling performance for the CPU in the controller 30, the output suppression temperature Tth is set lower than the operation stop temperature TIh of the inverter. Specifically, the output suppression temperature Tth is set lower than the operation stop temperature, which is a reference temperature for temperature abnormality, which is one of the events in which the IPM error signal is output in the IPM 18a of the inverter 18. Thus, before the inverters 18A, 18B, and 18C start the operation of the mechanism that stops the supply of current to the motor generator 12, the boom regeneration generator 300, and the turning motor 21, the upper limit value of the supplied current Is controlled by the controller 30 so as to reduce. Therefore, the motor generator 12, the boom regeneration generator 300, and the turning electric motor 21 are prevented from being stopped due to temperature abnormalities, and the excavator 1 can be continuously operated. Details of the control performed by the controller 30 will be described later.

  The inverter control units 30A, 30B, and 30C are parts that control the inverters 18A, 18B, and 18C, respectively. Here, the inverter control unit 30 will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the inverter control unit 30C. The inverter control units 30A and 30B have the same configuration as the inverter control unit 30C.

  As shown in FIG. 6, the inverter control unit 30C (30) includes a subtractor 31, a PI control unit 32, a torque limiting unit 33, a subtractor 34, a PI control unit 35, a current conversion unit 37, a turning motion detection unit 38, and A PWM signal generation unit 40 is provided.

  The subtractor 31 subtracts the turning speed value detected by the turning motion detection unit 38 from the speed command value of the turning speed of the work element driven by the turning electric motor 21 and outputs a deviation. The speed command value of the turning speed is, for example, a command value corresponding to the operation amount of the operating device 26 (see FIG. 2), and is sent from the overall control unit 30D of the controller 30.

  The resolver 22 detects a change in the rotational position of the turning electric motor 21. The turning motion detection unit 38 calculates a turning speed value based on the change in the rotational position of the turning electric motor 21 and outputs it to the subtractor 31.

  Based on the deviation output from the subtractor 31, the PI control unit 32 performs PI control so that the rotational speed of the turning electric motor 21 approaches the speed command value and the deviation becomes small, and the torque current for the control Generate a command value. The PI control unit 32 outputs the torque current command value to the torque limiting unit 33.

The torque limiting unit 33 sets the torque current command value to a predetermined torque so that the torque generated in the turning electric motor 21 by the torque current command value output from the PI control unit 32 is less than or equal to the allowable torque value of the turning electric motor 21. Limit to the limit value (torque upper limit) range. The torque limit value is sent from the overall control unit 30D, and the torque limit unit 33 acquires the sent torque limit value. In the inverter control unit 30C that controls the inverter 18C, in normal times, for example, the acceleration torque limit value _XU is 150% of the rated torque of the turning electric motor 21 to be driven, and the deceleration torque limit value _XD is 250% of the rated torque. Set to

  Here, the torque limit value setting process executed in the overall control unit 30D of the controller 30 will be described with reference to the flowchart of FIG.

  In step S1, the overall control unit 30D determines whether or not the temperature T of the cooling water acquired from the water temperature gauge 404 is higher than a predetermined output suppression temperature Tth. The output suppression temperature Tth is set to 60 ° C., for example. If the cooling water temperature T is higher than the predetermined output suppression temperature Tth, the process proceeds to step S2. If the cooling water temperature T is not higher than the predetermined output suppression temperature Tth, the determination process of step S1. Is repeated.

In step S2, the overall control unit 30D has a torque limit value for the torque limiting part 33 of the inverter control section 30, the acceleration torque limit value X _U and the deceleration torque limit value X _D, acceleration suppressing torque limit value X _U ^* and changing the time to suppress the torque limit value _X ^{D *} deceleration. The suppression torque limit value X _U ^* during acceleration is set to, for example, 100% of the rated torque in the turning electric motor 21, and the suppression torque limit value X _D ^* during deceleration is set to, for example, 150% of the rated torque in the turning electric motor 21. Is done. Thereby, the inverter 18C can be controlled so as to reduce the upper limit value of the current supplied to the turning electric motor 21. The rated torque used as a reference for setting is a value corresponding to the driving target such as the motor generator 12, the boom regeneration generator 300, and the turning motor 21.

In step S3, the overall control unit 30D determines whether or not the temperature T of the cooling water acquired from the water temperature gauge 404 has returned to the output suppression temperature Tth or less. When the cooling water temperature T is equal to or lower than the output suppression temperature Tth, the process proceeds to step S4. When the cooling water temperature T is not equal to or lower than the output suppression temperature Tth, the determination process of step S3 is repeated. As the torque limit value, the acceleration suppression torque limit value _XU ^* and the deceleration suppression torque limit value _XD ^* remain set.

In step S4, the overall control unit 30D determines the torque limit value for the torque limiting unit 33 from the acceleration suppression torque limit value X _U ^* and the deceleration suppression torque limit value X _D ^*, and the acceleration torque limit value X _U. and return to the deceleration torque limit value X _D.

  Referring again to FIG. 6, the subtractor 34 subtracts the output value from the current converter 37 from the torque current command value output from the torque limiter 33 and outputs a deviation.

  The current converter 37 detects the current value of the motor drive signal of the turning electric motor 21, converts the detected current value of the motor drive signal into a value corresponding to the torque current command value, and outputs it to the subtractor 34.

  The PI control unit 35 acquires the deviation output from the subtractor 34, performs PI control so that the deviation becomes small, and generates a drive command for driving the inverter 18C. The PI control unit 35 outputs a drive command to the PWM signal generation unit 40.

  The PWM signal generation unit 40 generates a PWM signal for switching control of the transistor of the inverter 18C based on the drive command from the PI control unit 35, and outputs the PWM signal to the inverter 18C.

  Next, FIG. 8 shows the torque, the turning speed of the turning body 4, and the rotation speed of the turning electric motor 21 when the torque limit value is set by the overall control unit 30 </ b> D of the controller 30. FIG. 8A is a graph showing the state of torque that changes with time according to the driving operation, and FIG. 8B is a graph showing the turning speed of the revolving structure 4, and FIG. ) Is a graph showing the rotational speed of the electric motor 21 for turning. In these graphs, the normal time is indicated by a solid line, and when the torque limit value is changed, it is indicated by a broken line.

  As shown in FIGS. 8A and 8B, at the time t0 to t1, the turning of the turning body 4 is accelerated at a torque of 150% of the rated torque of the turning electric motor 21 at normal times. On the other hand, when the torque limit value is changed, the turning of the turning body 4 is accelerated at a torque of 100% of the rated torque at times t0 to t2. The acceleration when the torque limit value is changed is smaller than that at the normal time. Further, the turning speed reached as a result of acceleration when the torque limit value is changed is slower than the normal time and is about 60% of the normal time.

  When the deceleration operation is performed from the time t3, the turning of the revolving structure 4 is normally decelerated at 250% of the rated torque of the turning electric motor 21 at the times t3 to t4. On the other hand, when the torque limit value is changed, the turning of the swing body 4 is decelerated at a torque of 150% of the rated torque at times t3 to t5. The acceleration when the torque limit value is changed is smaller than that at the normal time. Further, when the torque limit value is changed, more time is required for stopping compared to the normal time.

  Further, as shown in FIG. 8 (c), due to the fact that the rotational speed of the engine 11 is constant, the rotational speed of the turning electric motor 21 is constant both when the torque limit value is changed and during normal times. Become. For this reason, the torque varies depending on the load on the turning motor 21, and current is supplied from the inverter 18 </ b> C to the turning motor 21 in response to the varying torque. Therefore, the upper limit of the current supplied to the turning electric motor 21 can be controlled by setting the torque limit value.

  As described above, in the excavator 1 of the present embodiment, when the temperature of the cooling water for cooling the inverter 18 becomes equal to or higher than the output suppression temperature Tth, the excavator 1 is supplied to the AC motor such as the turning motor 21. Since the upper limit value of the current is reduced, the temperature rise in the inverter 18 is suppressed. Since the output suppression temperature Tth is lower than the operation stop temperature TIh in the IPM 18a, the upper limit value of the current that the inverter 18 supplies to the AC motor before the inverter 18 starts the operation of the mechanism that stops the supply of current to the AC motor. Control to reduce the value is performed by the controller. Thus, since the machine of the shovel 1 can be stopped when the detected value of the temperature sensor in the inverter 18a becomes equal to or higher than the operation stop temperature TIh, it is necessary to stop the machine immediately even if the temperature of the cooling water rises. There is no. Thereby, the stop by the temperature abnormality of the inverter 18 is prevented, and the continuous operation of the shovel 1 is realized.

  In the above embodiment, the excavator 1 is shown as an example of the hybrid type construction machine according to the present invention, but other examples of the hybrid type construction machine of the present invention include a lifting magnet vehicle, a wheel loader, a crane, and the like. Can be mentioned.

  DESCRIPTION OF SYMBOLS 1 ... Excavator, 2 ... Traveling mechanism, 2A ... Hydraulic motor, 3 ... Turning mechanism, 4 ... Turning body, 4a ... Driver's cab, 5 ... Boom, 6 ... Arm, 7 ... Boom cylinder, 7A ... Hydraulic pipe, 8 ... Arm Cylinder, 9 ... Bucket cylinder, 10 ... Bucket, 11 ... Engine, 12 ... Motor generator, 13 ... Reduction gear, 14 ... Main pump, 15 ... Pilot pump, 16 ... High pressure hydraulic line, 17 ... Control valve, 18, 18A , 18B, 18C ... inverter, 18b ... various sensors, 21 ... electric motor for turning, 22 ... resolver, 23 ... mechanical brake, 24 ... turning speed reducer, 25 ... pilot line, 26 ... operating device, 27, 28 ... hydraulic line, 29 ... Pressure sensor, 30 ... Controller, 30A, 30B, 30C ... Inverter control unit, 30D ... Overall control unit, 31 ... Subtractor, 32 Control unit 33 ... Torque limiter 34 ... Subtractor 35 ... Control unit 37 ... Current converter 38 ... Turning motion detector 40 ... PWM signal generator 100 ... Power storage means 101 ... Battery 102 ... Buck-boost converter, 300 ... boom regeneration generator, 310 ... hydraulic motor, 400 ... tank, 401 ... pump, 402 ... pump motor, 403 ... radiator, 404 ... water thermometer.

Claims (3)

An AC motor for driving the working element;
First drive control means for driving and controlling the AC motor;
A cooling device for cooling the first drive control means;
Temperature detecting means for detecting the temperature of the refrigerant in the cooling device;
A controller for controlling the first drive control means,
When the first drive control unit detects that the temperature of the first drive control unit is equal to or higher than a predetermined operation stop temperature, the first drive control unit stops supplying current for driving the AC motor , A mechanism for stopping the operation of the first drive control means ;
When the temperature of the refrigerant acquired from the temperature detection unit is higher than a predetermined output suppression temperature, the controller is supplied to the AC motor as compared with a case where the temperature of the refrigerant is equal to or lower than the output suppression temperature. Controlling the first drive control means to reduce the upper limit value of the current to be
The hybrid construction machine, wherein the output suppression temperature is lower than the shutdown temperature.   The said controller controls the said drive control means so that the upper limit of the electric current supplied to the said AC motor may be made small by restrict | limiting the upper limit of the torque which the said AC motor generates. The hybrid construction machine according to 1. A motor generator connected to the internal combustion engine;
Second drive control means for driving and controlling the motor generator;
The cooling device cools the first and second drive control means,
The controller controls the first and second drive control means, and when the temperature of the refrigerant acquired from the temperature detection means is higher than a predetermined output suppression temperature, the temperature of the refrigerant is suppressed to the output suppression. The first and second drive control means are controlled so as to reduce the upper limit value of the current supplied to the AC motor and the motor generator as compared with the case where the temperature is lower than the temperature. The hybrid construction machine according to 1 or 2.

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