JP5188854B2 - Hybrid construction machine - Google Patents

Description

  The present invention relates to a construction machine, and more particularly to a hybrid construction machine that performs work efficiently by using two power sources in combination.

  Hybrid work machines that operate efficiently by combining the power of an internal combustion engine and the power of an electric motor have been developed and used. 2. Description of the Related Art As a hybrid work machine, one that takes a so-called parallel drive form is known.

  In the parallel drive mode, a hydraulic pump and a power machine that performs a generator action and a motor action are connected in parallel to an internal combustion engine (engine) as a common power source. The hydraulic actuator is driven by the hydraulic pump, and the power storage device is charged by the generator action of the power machine. The power is operated from the power storage device as an electric motor to assist the engine. In addition, as a motive power machine, there are a case where a dual-purpose machine (generator / motor) that performs both a generator action and a motor action is used, and a case where a separate generator and motor are used together.

  According to such a hybrid work machine, energy saving can be realized by reducing the load on the engine and operating the engine in a high efficiency range. However, the conventional hybrid work machine has the following problems.

  The charge / discharge characteristics of power storage devices such as batteries (secondary batteries) such as lithium ion capacitors and capacitors (electric double layer capacitors) depend on the amount of charge, and the lower the amount of charge, the greater the maximum charging power. The discharge power is reduced. Therefore, since the power distribution between the engine and the power storage device is determined regardless of the charge amount of such a power storage device, the charge amount of the power storage device is too small or too large depending on the load condition. As a result, the capacity of the power storage device cannot be used effectively, and the power storage device may be deteriorated.

Such a problem of deterioration of the power storage device similarly occurs in a hybrid vehicle. Therefore, it has been proposed to prevent charging from the generator by providing a switch between the electric motor for traveling and the generator driven by the engine and turning off the switch during coasting operation or braking. (For example, refer to Patent Document 1).
JP 2006-141116 A

  In a hybrid construction machine, there are often a plurality of electric drive units, and regenerative power from the electric drive system increases, which may exceed the chargeable amount of the battery. Even in such a case, if all the regenerative power is turned to charge the battery, the battery deteriorates early, and in the worst case, the battery may be destroyed.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hybrid construction machine that prevents battery overcharge due to regenerative power.

In order to solve the above-described problem, according to the present invention, a hydraulic generator that is mechanically connected to an engine at all times so as to be intermittent , converts an output of the engine into hydraulic pressure, and supplies the hydraulic drive unit, and the engine A motor generator that is connected and functions as both a motor and a generator; a capacitor that supplies electric power to the motor generator to function as a motor; and that is driven by the power from the capacitor and the motor generator; An electric drive unit that generates electric power and supplies it to at least one of the capacitor and the motor generator; a control unit that controls the operation of the motor generator; and is provided between the motor generator and the capacitor. There is provided a hybrid construction machine having an electrical shut-off device controlled to be opened and closed by the control unit.

  According to the present invention, by forcibly blocking the electrical path to the battery based on the charge rate of the battery, for example, charging by the generated current of the motor generator is not performed, and overcharging of the battery is prevented. be able to.

  Next, embodiments of the present invention will be described with reference to the drawings.

  First, a hybrid excavator will be described as an example of a hybrid construction machine to which the present invention is applied.

  FIG. 1 is a side view of a hybrid excavator. An upper swing body 3 is mounted on the lower traveling body 1 of the power shovel via a swing mechanism 2. A boom 4 extends from the upper swing body 3, and an arm 5 is connected to the tip of the boom 4. Further, the bucket 6 is connected to the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. The upper swing body 3 is mounted with a cabin 10 and a power source (not shown).

  FIG. 2 is a block diagram showing the configuration of the drive system of the power shovel shown in FIG. In FIG. 2, the hydraulic system line is indicated by a thin solid line, the electric system line is indicated by a thick solid line, and the electric control system line is indicated by a broken line.

  An engine 11 as a mechanical drive unit and a motor generator 12 (also referred to as an assist motor 12) as an assist drive unit are both connected to a speed reducer 13 (also functions as a splitter) as a booster. A hydraulic pump 14 is connected to the output shaft of the speed reducer 13. A control valve 17 is connected to a hydraulic pump 14 that is a hydraulic generator via a high-pressure hydraulic line 16.

  The control valve 17 is a control device that controls the hydraulic system. Connected to the control valve 17 are hydraulic motors 1A (for right) and 1B (for left), a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 for the lower traveling body 1 via a high-pressure hydraulic line. Further, a boom regenerative hydraulic motor 7B is connected to the control valve 17 via a boom regenerative valve 7A.

  A battery 19 as a battery is connected to the motor generator 12 via an inverter 18A and a converter 18B.

  A swing motor 21 is connected to the battery 19 via an inverter 20 and a converter 18B. The turning motor 21 is an electric drive unit (electric load) in the power shovel, and can rotate the turning table 22 and generate regenerative power. In addition, a boom regenerative motor 24 that is an electric drive unit (electric load) is connected to the battery 19 via an inverter 23. The boom regenerative motor 24 is connected to the boom regenerative hydraulic motor 7B, can drive the boom regenerative hydraulic motor 7B to operate the boom cylinder 7, and is driven by the boom regenerative hydraulic motor 7B to generate regenerative power. can do. Further, a lifting magnet (abbreviated as a lifting magnet) 25, which is an electric drive unit (electric load) made of an electromagnet, is connected to the battery 19 through an inverter 25.

  As described above, the boom regeneration motor 24, the turning motor 21, and the riff mug 26, which are electric loads, are connected to the motor generator 12 by the power line 27 and can be driven by the power from the motor generator 12. Further, the battery 19 is connected to the power line 27 by a power line 28, and the boom regenerative motor 24, the turning motor 21, and the riff mug 26 can be driven by power from the battery 19. Further, the battery 19 is connected to the motor generator 12 by the power lines 27 and 28, and the battery 19 can be charged by the power from the motor generator 12, and the motor generator 12 can be charged by the power from the battery 19. It can also be driven.

  The power shovel having the above configuration is a hybrid construction machine that uses the engine 11, the motor generator 12, the turning motor 21, and the boom regenerative motor 24 as power sources. These power sources are mounted on the upper swing body 3 shown in FIG. Hereinafter, each part will be described.

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

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

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

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

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

  The inverter 18 is provided between the motor generator 12 and the battery 19 as described above, and controls the operation of the motor generator 12 based on a command from the controller 30. As a result, when the inverter 18 is operating and controlling the motor (assist) of the motor generator 12, necessary power is supplied from the battery 19 to the motor generator 12. Further, when the operation of the power generation of the motor generator 12 is controlled, the battery 19 is charged with the power generated by the motor generator 12.

  The battery 19 serving as a storage device supplies electric power necessary for the electric operation or the power running operation when at least one of the motor generator 12, the swing motor 21 and the boom regenerative motor 24 is performing the electric operation or the power running operation. In addition, when at least one of the power generation operation or the regenerative operation is performed, the power source is a power source for storing the generated power or the regenerative power generated by the power generation operation or the regenerative operation as electric energy.

  The inverter 20 is provided between the swing motor 21 and the battery 19 as described above, and performs operation control on the swing motor 21 based on a command from the controller 30. Thus, when the swing motor 21 is in a power running operation, necessary power is supplied from the battery 19 to the swing motor 21. Further, when the swing motor 21 is performing a regenerative operation, the battery 19 is charged with the electric power generated by the swing motor 21.

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

  The charge / discharge control of the battery 19 is based on the state of charge of the battery 19, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state of the turning motor 21 (power running operation or regenerative operation). Performed by the controller 30.

  The controller 30 is a control device that performs drive control of the power shovel, and includes a speed command conversion unit, a drive control device, and a turning drive control device. The controller 30 is composed of an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory. The speed command conversion unit, the drive control device, and the turning drive control device are realized by the CPU of the controller 30 executing a drive control program stored in an internal memory.

  Next, the hybrid construction machine according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the drive system of the hybrid construction machine according to the first embodiment of the present invention. 3, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

  In the hybrid construction machine according to the first embodiment of the present invention, the electrical interrupting device 40 capable of interrupting the power line is provided in the power line connected to the battery 19. The electrical interrupting device 40 includes a switch SW <b> 1 provided in the middle of the power line 27 and a switch SW <b> 2 provided in the middle of the power line 28. The switching operation of the switches SW1 and SW2 is controlled by the controller 30.

  The above-described switches SW1 and SW2 may be any switches as long as they open and close the electrical path according to a signal from the controller 30. As the switches SW1 and SW2, various relays such as a relay that mechanically opens and closes a contact or a solid state relay that electronically opens and closes can be used.

  By setting the switch SW1 to ON (closed), electric power can be supplied to the motor generator (assist motor) 12 to perform electric (assist) operation, and the motor generator 12 can be operated as a generator to operate electric power. Can be output. On the contrary, by setting the switch SW1 to OFF (open), the motor generator (assist motor) 12 is prohibited from being electrically operated (assist), and the motor generator 12 is also prohibited from being operated as a generator. Can do.

  When the switch SW2 is turned on (closed), the battery 19 can be charged and discharged. In other words, power can be supplied from the battery 19 to drive each electric drive unit, and power can be supplied to the battery 19 for charging. On the contrary, charging / discharging of the battery 19 can be prohibited by turning off the switch SW2.

  The drive system can be controlled as follows by the combination of opening and closing of the switches SW1 and SW2.

  First, by turning on the switch SW1 and turning off the switch SW2, it is possible to prevent the battery 19 from being overcharged or to suppress an excessive increase in the charge rate SOC. For example, when the charge rate SOC of the battery 19 is higher than the target charge rate, the SW2 is turned off, for example, so that regenerative power generated by the turning motor 21 is not supplied to the battery 19 and the battery 19 is protected. Can do. In this case, since the switch SW1 is ON, the regenerative power is supplied to the motor generator 12 and consumed.

  When the storage rate SOC of the battery 19 becomes smaller than the target charging rate, the switch SW2 is turned on to supply power to the battery 19 so that the battery 19 can be charged. Thereby, for example, the electric power generated by the motor generator 12 can be supplied to the battery 19 and charged.

  When only the swing motor 21 or the boom regenerative motor 24 is powered, the switch SW1 is turned off and the switch SW2 is turned on. Thereby, the electric power discharged from the battery 19 is supplied to the turning motor 21 or the boom regenerative motor 24 without being supplied to the motor generator, and the turning table 22 and the boom cylinder 7 can be electrically driven.

  As described above, in the present embodiment, the controller 30 that is a control unit appropriately protects the battery 19 by controlling the opening / closing operation of the electrical interrupting device 40 according to the storage rate of the battery 19 that is a capacitor. Can do.

  Next, a hybrid construction machine according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the drive system of the hybrid construction machine according to the second embodiment of the present invention. 4, parts that are the same as the parts shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted.

  In the hybrid construction machine according to the second embodiment of the present invention, an electrical interrupting device 40A capable of interrupting the power line is provided in the power line connected to the battery 19. The electric circuit breaker 40A includes a switch SW1 provided in the middle of the power line 27, a switch SW2 provided in the middle of the power line 28, and a rectifier RC1 connected in parallel to the switch SW2. The switching operation of the switches SW1 and SW2 is controlled by the controller 30.

  The drive system can be controlled as follows by the combination of opening and closing of the switches SW1 and SW2.

  First, by turning on the switch SW1 and turning off the switch SW2, it is possible to prevent the battery 19 from being overcharged or to suppress an excessive increase in the charge rate SOC. For example, when the charge rate SOC of the battery 19 is higher than the target charge rate, the SW2 is turned off, for example, so that regenerative power generated by the turning motor 21 is not supplied to the battery 19 and the battery 19 is protected. Can do. In this case, since the switch SW1 is ON, the regenerative power is supplied to the motor generator 12 and consumed. Here, even if the switch SW1 is broken or malfunctions and is not turned ON, since the rectifier RC1 is connected in parallel to the switch SW1, the regenerative power can be surely released to the motor generator 12 side. In addition to the electric battery 19, the electric interrupting device 40 can be protected.

  When the storage rate SOC of the battery 19 becomes smaller than the target charging rate, the switch SW2 is turned on to supply power to the battery 19 so that the battery 19 can be charged. Thereby, for example, the electric power generated by the motor generator 12 can be supplied to the battery 19 and charged.

  When only the swing motor 21 or the boom regenerative motor 24 is powered, the switch SW1 is turned off and the switch SW2 is turned on. Thereby, the electric power discharged from the battery 19 is supplied to the turning motor 21 or the boom regenerative motor 24 without being supplied to the motor generator, and the turning table 22 and the boom cylinder 7 can be electrically driven.

  Next, a hybrid construction machine according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the drive system of the hybrid construction machine according to the third embodiment of the present invention. 5, parts that are the same as the parts shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted.

  In the hybrid construction machine according to the third embodiment of the present invention, an electrical interrupting device 40B capable of interrupting the power line is provided in the power line connected to the battery 19. The electrical interrupting device 40 </ b> B includes an electrical switching device 42 provided in the middle of the power line 27 and a switch SW <b> 2 provided in the middle of the power line 28. The electrical switching device 42 includes a switch SW1 and rectifiers RC1 and RC2 connected in parallel. The rectifier RC1 forms a circuit in which current flows only in the direction from the battery 19 to the motor generator 12, and the rectifier RC2 forms a circuit in which current flows only in the direction from the motor generator 12 to the battery 19. The switching operation of the switches SW1 and SW2 is controlled by the controller 30.

  The drive system can be controlled as follows by the combination of opening and closing of the switches SW1 and SW2.

  First, by switching the switch SW1 to the NC side and turning off the switch SW2, it is possible to prevent the battery 19 from being overcharged or to suppress an excessive increase in the charging rate SOC. For example, when the charging rate SOC of the battery 19 becomes higher than the target charging rate, the regenerative power generated by the turning motor 21 is supplied to the battery 19 by turning off the SW2 and switching the switch SW1 to the NC side, for example. This prevents the battery 19 from being protected. In this case, since the switch SW1 is connected to the NC side, the regenerative power passes through the rectifier RC1 and the switch SW1 and is supplied to the motor generator 12 and consumed.

  When the storage rate SOC of the battery 19 becomes smaller than the target charging rate, the switch SW2 is turned on and the switch SW1 is switched to the NO side, so that the electric power generated by the motor generator 12 is supplied to the battery 19. Make it ready for charging. Thereby, for example, the electric power generated by the motor generator 12 can be supplied to the battery 19 and charged.

  Further, for example, when the turning motor 21 is powered, the switch SW2 is turned off and the switch SW1 is switched to the NO side. Thereby, the electric power stored in the battery 19 can be supplied to the turning motor 21 without supplying it to the motor generator 12 side.

  Further, when the storage amount of the battery 19 decreases, the power supply from the battery 19 to the turning motor 21 is stopped by turning off the switch SW2 and switching the switch SW1 to the NO side. It can be changed to power supply. In this case, since the rectifier RC2 is connected in series with the switch SW1, for example, even if the power running operation of the turning motor 21 is suddenly changed to the regenerative operation, a large regenerative power is suddenly supplied to the motor generator 12. There is nothing. Therefore, the inverter 18A connected in front of the motor generator 12 can be protected from large regenerative power.

  As described above, in the present embodiment, the electrical interrupting device 40B includes the electrical switching device 42. The electrical switching device 42 switches between a circuit in which current flows only in the direction from the battery 19 serving as a capacitor to the motor generator 12 and a circuit in which current flows only in the direction from the motor generator 12 to the battery 19. The inverter 18A can be protected while protecting the battery 19.

  Next, a hybrid construction machine according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of the drive system of the hybrid construction machine according to the fourth embodiment of the present invention. 6, parts that are the same as the parts shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted.

  In the hybrid construction machine according to the fourth embodiment of the present invention, an electrical interrupting device 40 capable of interrupting the power line is provided in the power line connected to the battery 19. The electrical interrupting device 40 includes a switch SW <b> 1 provided in the middle of the power line 27 and a switch SW <b> 2 provided in the middle of the power line 28. The switching operation of the switches SW1 and SW2 is controlled by the controller 30.

  The above configuration is the same as that of the hybrid construction machine according to the first embodiment described above, except that the lifting magnet 26 is connected between the inverter 18A and the electrical interrupting device 40 via the inverter 25. That is, by connecting the lifting magnet 26 to the motor generator 12 side from the electrical interrupting device 40, power is supplied from the motor generator 12 to the lifting magnet 26 via the inverter 18A and the inverter 25 even when the switch SW2 is turned off. can do.

  For example, even if the switch SW2 is accidentally turned OFF while using the lifting magnet 26, the electric power is supplied from the motor generator 12 to the lifting magnet 26, so that the electromagnetic attracting force of the lifting magnet 26 will not be lost. . For this reason, it is possible to prevent the adsorbate being lifted by the lifting magnet 26 from dropping unexpectedly. This is effective when applied to an electric drive unit that is in a dangerous state when the supply of power is stopped unexpectedly, such as the lifting magnet 26, and can provide safe operation.

It is a side view of a hybrid type power shovel. It is a block diagram showing the structure of the drive system of the power shovel shown in FIG. It is a block diagram which shows the structure of the drive system of the hybrid type construction machine by 1st Embodiment of this invention. It is a block diagram which shows the structure of the drive system of the hybrid type construction machine by 2nd Embodiment of this invention. It is a block diagram which shows the structure of the drive system of the hybrid type construction machine by 3rd Embodiment of this invention. It is a block diagram which shows the structure of the drive system of the hybrid type construction machine by 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Traveling mechanism 2 Turning mechanism 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 7A Boom regeneration valve 7B Boom regeneration hydraulic motor 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Deceleration Machine (splitter)
DESCRIPTION OF SYMBOLS 14 Hydraulic pump 16 High pressure hydraulic line 17 Control valve 18A, 20, 23, 25 Inverter 18B Converter 19 Battery 21 Turning motor 22 Turning table 24 Boom regeneration motor 26 Lifting magnet 27, 28 Electric power line 30 Controller 40, 40A, 40B, 40C Electricity Circuit breaker 42 Electric switching device SW1, SW2 Switch RC1, RC2 Rectifier

Claims (5)

A hydraulic pressure generator that is mechanically connected to the engine at all times in an intermittent manner, converts the output of the engine into hydraulic pressure, and supplies the hydraulic pressure to a hydraulic drive unit;
A motor generator connected to the engine and functioning as both a motor and a generator;
A capacitor that supplies electric power to the motor generator to function as an electric motor;
An electric drive unit that is driven by electric power from the electric storage device and the motor generator, and generates regenerative electric power to supply to at least one of the electric storage device and the motor generator;
A control unit for controlling the operation of the motor generator;
A hybrid construction machine, comprising: an electric interrupting device provided between the motor generator and the battery and controlled to be opened and closed by the control unit. The hybrid construction machine according to claim 1,
The hybrid construction machine, wherein the control unit controls an opening / closing operation of the electric circuit breaker according to a storage rate of the capacitor. The hybrid construction machine according to claim 1,
The electrical interrupting device includes an electrical switching device, and the electrical switching device includes a circuit in which current flows only in a direction from the capacitor to the motor generator, and a circuit in which current flows only in a direction from the motor generator to the capacitor. Hybrid construction machine characterized by switching between the two. The hybrid construction machine according to claim 1,
The electric circuit breaker includes two switches connected in series between the capacitor and the motor generator, and the electric drive unit is connected between the two switches. Construction machine. The hybrid construction machine according to claim 1,
Having a lifting magnet made of an electromagnet as part of the electric drive unit;
The lifting magnet is connected between the electric breaker and the motor generator.

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