JP2014128156A - Inverter system for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter system for a construction machine which, when an arm breaks down, ensures that a motor is operated normally.SOLUTION: A reserve arm 13 is provided separately from three arms 12U, 12V, 12W provided corresponding to each phase of a three-phase motor 10. When, for example, switching elements 21, 22 of the arm 12U break down, a connection cable 9U connected to a U phase of the three-phase motor 10 is removed from a connector 23U connected to the arm 12U and reconnected to a reserve connector 24 connected to the reserve arm 13. At this time also, a controller 15 stops input of a control signal to the switching elements 21, 22 of the arm 12U, and inputs the same control signal as was hitherto input to the switching elements 21, 22 of the arm 12U, to the switching elements 21, 22 of the reserve arm 13.

Description

  The present invention relates to a construction machine inverter system for driving a three-phase motor in a construction machine.

  In the motor drive system described in Patent Literature 1, an arm provided for a phase of a DC brushless motor is configured in an inverter that drives a three-phase DC brushless motor (three-phase motor) for rotating a fan. When one of the two switching elements fails, the other switching element is always turned off to drive the DC brushless motor. Thereby, it is possible to continue driving the DC brushless motor while preventing both ends of the power supply from being short-circuited via the two switching elements. However, at this time, there is a section where no torque is generated in the DC brushless motor. Therefore, when starting the DC brushless motor, the rotor of the DC brushless motor is fixed in a state where the quasi-normal torque is generated. Then, the DC brushless motor is started.

JP 2010-246210 A

  In Patent Document 1, as described above, the three-phase motor can be driven while preventing both ends of the power supply from being short-circuited when the switching element fails, but the section in which torque is not generated in the three-phase motor. is there. Therefore, as described in Patent Document 1, if the fan is only rotated by a three-phase motor, it is not so much except that it is necessary to fix the rotor in a state where torque is generated at startup. Although not a big problem, for example, when a three-phase motor is for operating the operating part of the construction machine, if the desired torque cannot be obtained, the operating part of the construction machine can be operated normally. There is a possibility of not being able to. In addition, in a three-phase motor for operating the operating part of a construction machine, rotation and braking are repeated during work by the construction machine, so each time it is rotated, the three-phase motor is in a section where torque is generated. It is not realistic to fix in a positioned state.

  Here, there is no problem if the failed switching element can be replaced immediately. However, in construction machines, a large number of pipes and electrical connection cables are generally housed in a small space at a high density. When a switching element fails, it is difficult to replace the switching element at the work site. To replace the switching element, it is usually necessary to move the construction machine to a repair site. For this reason, when the switching element breaks down, it becomes impossible to work with the construction machine for a long period of time.

  The objective of this invention is providing the inverter system for construction machines which can operate an electric motor normally also at the time of failure of an arm.

  An inverter system according to the present invention includes a three-phase motor, three arms provided corresponding to each phase of the three-phase motor, at least one spare arm having the same configuration as the arm, the arm, By inputting a control signal to the spare arm, the controller that controls the operation of the arm and the spare arm, and when one of the three arms fails, the failed arm is identified to the controller. Fault arm identification means for causing each phase of the three-phase motor to be selectively connectable to either the corresponding arm or the spare arm, and the control device Based on the failure arm identification means, the failed arm is identified, the control signal input to the failed arm is stopped, and the failed arm The same control signal as has been input, wherein the input to the pre-arm.

  According to the present invention, when any arm fails, the control signal that has been input to the failed arm is input to the spare arm, so the phase corresponding to the failed arm of the three-phase motor is The three-phase motor can be driven normally by changing the connected arm to the spare arm. At this time, the control signals input from the control device to the three arms are different in phase, but in the present invention, the control device can identify the failed arm based on the failure arm identification means, It is possible to stop the input of the control signal to and to input the same signal to the spare arm as was input to the failed arm.

It is a figure which shows the structure of the inverter system which concerns on 1st Embodiment. In 1st Embodiment, it is a figure which shows switching of the connection of a three-phase motor when a U phase fails. It is a figure which shows the structure of the connection part with the three-phase motor of the inverter system which concerns on 2nd Embodiment. In 2nd Embodiment, it is a figure which shows switching of a connection when a U phase fails. FIG. 9 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG.

[First Embodiment]
Hereinafter, a preferred first embodiment of the present invention will be described.

  As shown in FIG. 1, the inverter system 1 according to the first embodiment includes a three-phase motor 10, a DC power supply 11, three arms 12U, 12V, 12W, a spare arm 13, a connection unit 14, and a controller 15 (control device). It has.

  The three-phase motor 10 is a three-phase motor included in a construction machine, such as a three-phase motor for turning an upper swing body and a three-phase motor for operating a hydraulic pump in a hybrid excavator. The DC power supply 11 is a secondary battery or the like. The three arms 12U, 12V, and 12W are connected to the DC power supply 11 in parallel. Each of the arms 12U, 12V, and 12W includes two switching elements 21 and 22 connected in series to the DC power supply 11, respectively. The switching elements 21 and 22 are semiconductor switching elements such as transistors, for example. In accordance with a control signal input from the controller 15, the switching elements 21 and 22 are turned on when both ends are turned on and turned off when both ends are cut off. Can be switched.

  The spare arm 13 is connected to the DC power supply 11 in parallel with the arms 12U, 12V, and 12W. The spare arm 13 has the same configuration as the arms 12U, 12V, and 12W, and includes two switching elements 21 and 22 connected in series to the DC power supply 11.

  A common capacitor 16 is connected to the arms 12U, 12V, 12W and the spare arm 13. Also, individual feedback diodes 17 are connected to the switching elements 21 and 21 of the arms 12U, 12V, and 12W and the spare arm 13, respectively. The feedback diode 17 is provided to perform reactive power processing and the like.

  The connection unit 14 includes three connectors 23U, 23V, and 23W, a spare connector 24, and three limit switches 25U, 25V, and 25W (failure arm identification means). The connectors 23U, 23V, and 23W are connected to portions of the arms 12U, 12V, and 12W between the two switching elements 21 and 22, respectively. In addition, the connectors 23U, 23V, 23W are connected to the connecting cables 9U connected to the respective phases (U phase, V phase, W phase) of the three-phase motor 10 when the arms 12U, 12V, 12W are operating normally. 9V and 9W are connected.

  The spare connector 24 is connected to a portion of the spare arm 13 between the two switching elements 21 and 22. As will be described later, when any of the arms 12U, 12V, and 12W fails, the spare connector 24 is connected to a connection cable corresponding to the failed arm among the connection cables 9U, 9V, and 9W.

  Limit switches 25U, 25V, and 25W are disposed adjacent to connectors 23U, 23V, and 23W, respectively. The limit switches 25U, 25V, 25W are turned on by being pushed by the connection cables 9U, 9V, 9W when the connection cables 9U, 9V, 9W are connected to the connectors 23U, 23V, 23W. When 9U, 9V, and 9W are switched to the spare connector 24 and are no longer pushed by the connection cables 9U, 9V, and 9W, they are turned off. Then, each of the limit switches 25U, 25V, and 25W transmits a signal indicating whether the switch is on or off to the controller 15.

  The controller 15 controls on / off switching of the switching elements 21 and 22 of the arms 12U, 12V, and 12W and the spare arm 13 based on signals input from the limit switches 25U, 25V, and 25W, as will be described later. .

  Here, the operation of the inverter system 1 will be described. In any of the arms 12U, 12V, and 12W, the switching elements 21 and 22 are not out of order, and when the arms 12U, 12V, and 12W are operating normally, the connectors 23U, 23V, and 23W are connected to each other as described above. Connection cables 9U, 9V, and 9W are connected, respectively. In this state, an ON signal is input to the controller 15 from any of the limit switches 25U, 25V, and 25W. At this time, the controller 15 converts the DC voltage of the DC power supply 11 into a three-phase AC voltage in the arms 12U, 12V, and 12W and outputs it from the connection portion with the connectors 23U, 23V, and 23W. Control of switching on and off of the switching elements 21 and 22 of 12V and 12W is controlled. Note that the on / off switching control of the switching elements 21 and 22 at this time is the same as that in the related art, and a detailed description thereof is omitted here. As a result, a three-phase AC voltage is supplied to the three-phase motor 10, and the three-phase motor 10 operates.

  Next, a case where at least one of the switching elements 21 and 22 fails in any of the arms 12U, 12V, and 12W will be described. For example, when at least one of the switching elements 21 and 22 of the arm 12U fails, as shown in FIG. 2, an operator of the construction machine including the inverter system 1 disconnects the connection cable 9U from the connector 23U, Switch to spare connector 24. At this time, the signals input from the limit switches 25V and 25W to the controller 15 remain on, but the signals input from the limit switch 25U to the controller 15 are switched off. As a result, the controller 15 can identify that the arm 12U is a malfunctioning arm, and can determine that the connection cable 9U has been changed from the connector 23U to the spare connector 24.

  Upon receiving an OFF signal from the limit switch 25U, the controller 15 stops the input of the control signal to the switching elements 21 and 22 of the arm 12U and is output to the switching elements 21 and 22 of the arm 12U until then. The same control signal as that which has been output is output toward the switching elements 21 and 22 of the auxiliary arm 13. Thereby, the voltage and phase output from the connectors 23U and 23V and the spare connector 24 to the three-phase motor 10 are the same as those output until then. Therefore, the three-phase motor 10 can be operated normally as before.

  And when the switching elements 21 and 22 of the arm 12U break down, the three-phase motor 10 can be operated normally in the same way as before, so the work using the construction machine provided with the inverter system 1 Can continue. Thereby, it is possible to prevent the work using the construction machine from being interrupted for a long time. In the construction machine, after the work is completed, the construction machine is moved from the work site to the repair shop, and the failed switching elements 21 and 22 are replaced.

  Here, the case where the switching elements 21 and 22 of the arm 12U have failed has been described. However, when the switching elements 21 and 22 of the arms 12V and 12W have also failed, the three-phase motor is the same as described above. 10 can be operated normally as before.

[Second Embodiment]
Next, a preferred second embodiment of the present invention will be described. However, in the following, differences from the first embodiment will be mainly described.

  In 2nd Embodiment, the connection switching apparatus 40 is provided instead of the connection part 14 (refer FIG. 1) of 1st Embodiment. As shown in FIG. 3, the connection switching device 40 includes three motor side wires 41U, 41V, 41W, three arm side wires 42U, 42V, 42W, a spare wire 43, and three connection bars 44U, 44V, 44W. In FIG. 3, the motor side wirings 41U, 41V, 41W, the arm side wirings 42U, 42V, 42W, the spare wiring 43, and the connection bars 44U, 44V, 44W are hatched for easy understanding of the drawing. .

  The motor side wirings 41U, 41V, 41W extend in the left-right direction in FIG. 3 and are arranged in the up-down direction in FIG. The motor side wirings 41U, 41V, 41W are connected to connection cables 9U, 9V, 9W (see FIG. 1) through connectors or the like (not shown), respectively. The arm-side wirings 42U, 42V, 42W extend in the left-right direction in FIG. 3 and are arranged in the up-down direction in FIG. Further, the arm side wirings 42U, 42V, and 42W are arranged so as to be shifted from the motor side wirings 41U, 41V, and 41W to the lower side in FIG. The arm-side wirings 42U, 42V, and 42W are connected to portions between the switching elements 21 and 22 (see FIG. 1) of the arms 12U, 12V, and 12W (see FIG. 1), respectively.

  The spare wiring 43 includes three attachment portions 51U, 51V, 51W and a connecting portion 52. The three attachment portions 51U, 51V, and 51W are positions shifted from the electric motor side wirings 41U, 41V, and 41W to the upper side in FIG. 3 and the arm side wirings 42U, 42V, and 42W in the left-right direction in FIG. It is arranged at the same position as the right end of. The connecting part 52 is arranged immediately on the left side of the three attaching parts 51U, 51V, 51W in FIG. 3 and extends in the vertical direction in FIG. 3 to connect the attaching parts 51U, 51V, 51W to each other. Further, the connecting portion 52 has an upper end portion in FIG. 3 bent to the left side in FIG. 3, and this portion is connected to the two switching elements 21 and 22 (see FIG. 1) of the spare arm 13 (see FIG. 1). Connected to the part between.

  Here, the positional relationship of the motor side wirings 41U, 41V, 41W, the arm side wirings 42U, 42V, 42W, and the spare wiring 43 in the direction perpendicular to the sheet of FIG. 3 will be described. These are at least the left end portions of the motor side wirings 41U, 41V, 41W in FIG. 3, the right end portions of the arm side wirings 42U, 42V, 42W in FIG. , 51V, 51W are arranged at the same position in the direction perpendicular to the paper surface of FIG. Also, the arm-side wirings 42U, 42V, and 42W that overlap each other when viewed from the direction perpendicular to the paper surface of FIG. 3 and the connecting portion 52 are arranged so as not to contact each other.

  Specifically, for example, the motor side wirings 41U, 41V, 41W and the spare wiring 43 are arranged at the same position in the direction perpendicular to the sheet of FIG. 3, and the arm side wirings 42U, 42V, 42W are It is arranged on the front side in the direction perpendicular to the paper surface of FIG. The arm-side wirings 42U, 42V, and 42W are bent so that the right end in FIG. 3 is at the same position as the motor-side wirings 41U, 41V, 41W and the spare wiring 43 in the direction perpendicular to the sheet of FIG. It has been.

  Alternatively, for example, the motor side wirings 41U, 41V, 41W and the arm side wirings 42U, 42V, 42W are located at the same position in the direction perpendicular to the sheet of FIG. 3, and the spare wiring 43 is replaced by the motor side wiring 41U. , 41V, 41W and the arm side wirings 42U, 42V, 42W are located on the back side of the paper surface of FIG. The auxiliary wiring 43 is arranged such that the mounting portions 51U, 51V, 51W are located at the same positions as the motor-side wirings 41U, 41V, 41W and the arm-side wirings 42U, 42V, 42W in the direction perpendicular to the sheet of FIG. It is bent.

  One end of the connection bar 44U is connected to the motor-side wiring 41U by being attached to the motor-side wiring 41U with a mounting screw 46. The connection bar 44U can be swung around the attachment screw 46 in a state where the attachment screw 46 is loosened. The other end is an attachment screw 47, and the arm side wiring 42U is illustrated. 3 is selectively connected to either the arm-side wiring 42U or the attachment portion 51U by being selectively attached to either the right end portion or the attachment portion 51U.

  Similarly, one end of the connection bar 44V is connected to the motor side wiring 41V, and the other end is selectively connected to either the arm side wiring 42V or the mounting portion 51V. The connection bar 44W has one end connected to the motor side wiring 41W and the other end selectively connected to either the arm side wiring 42W or the mounting portion 51W.

  The limit switches 45U, 45V, and 45W are respectively disposed between the left end portions of the motor side wirings 41U, 41V, and 41W in FIG. 3 and the right end portions of the arm side wirings 42U, 42V, and 42W in FIG. The limit switches 45U, 45V, and 45W are respectively connected to the motor-side wirings 41U, 41V, and 41W and the arm-side wirings 42U, 42V, and 42W by the connection bars 44U, 44V, and 44W, respectively. Pressed by the connection bars 44U, 44V, 44W to turn on. On the other hand, the limit switches 45U, 45V, 45W are connected to the connection bars 44U, 44V in a state where the motor side wirings 41U, 41V, 41W and the mounting portions 51U, 51V, 51W are connected by the connection bars 44U, 44V, 44W, respectively. , 44W is not pushed and the state is turned off. Each of the limit switches 45U, 45V, 45W transmits a signal indicating whether the switch is on or off to the controller 15 (see FIG. 1).

  Here, the connection switching in the connection switching device 40 will be described. In any of the arms 12U, 12V, and 12W (see FIG. 1), the switching elements 21 and 22 (see FIG. 1) are not out of order and the arms 12U, 12V, and 12W are operating normally. The motor side wirings 41U, 41V, 41W and the arm side wirings 42U, 42V, 42W are connected by 44U, 44V, 44W, respectively. In this state, an ON signal is input to the controller 15 (see FIG. 1) from any of the limit switches 45U, 45V, and 45W, and the first implementation is performed from the controller 15 to the switching elements 21 and 22 of the arms 12U, 12V, and 12W. A control signal similar to that of the form is input.

  Next, a case where at least one of the switching elements 21 and 22 fails in any of the arms 12U, 12V, and 12W will be described. For example, when at least one of the switching elements 21 and 22 of the arm 12U fails, as shown in FIG. 4, the operator of the construction machine equipped with the inverter system 1 or the like connects the connection bar 44U to the arm side wiring 42U. To the attachment portion 51U. As a result, the signals input from the limit switches 45V and 45W to the controller 15 remain on, but the signals input from the limit switch 45U to the controller 15 are switched off. Thereby, the controller 15 can identify that the arm 12U is a malfunctioning arm, and can determine that the connection bar 44U has been changed from the arm side wiring 42U to the mounting portion 51U.

  The controller 15 receives the OFF signal from the limit switch 45U, stops input of the control signal to the switching elements 21 and 22 of the arm 12U, and has been input to the switching elements 21 and 22 of the arm 12U until then. The same control signal is input to the switching elements 21 and 22 of the auxiliary arm 13. Thereby, the voltage and phase output to the three-phase motor 10 from the motor side wirings 41U, 41V, 41W are the same as before. Therefore, the three-phase motor 10 can be operated normally as before.

  Here, the case where the switching elements 21 and 22 of the arm 12U have failed has been described. However, when the switching elements 21 and 22 of the arms 12V and 12W have also failed, the three-phase motor is the same as described above. 10 can be operated normally as before.

  Next, modified examples in which various changes are made to the first and second embodiments will be described. However, the description of the same configuration as in the first and second embodiments is omitted as appropriate.

  In the first and second embodiments, only one spare arm 13 is provided, but two or more spare arms may be provided. In this case, even if the switching elements 21 and 22 fail in two or more of the three arms 12U, 12V, and 12W, the three-phase motor 10 is switched from the failed arm to the spare arm. The driving of the phase motor 10 can be continued.

  Further, in the first and second embodiments, the controller 15 is made to identify the failed arm depending on whether or not the limit switch is pressed. However, the present invention is not limited to this. For example, the failed arm may be identified by the controller 15 by a configuration other than the limit switch, such as an optical sensor that detects the presence of the connection cables 9U, 9V, and 9W and the connection bars 44U, 44V, and 44W.

  In the first embodiment, when the limit switches 25U, 25V, and 25W are switched from the on state to the off state, the controller 15 connects the connection cables 9U, 9V, and 9W to the connectors 23U, 23V, and 23W, respectively. In the second embodiment, when the limit switches 45U, 45V, and 45W are switched from the on state to the off state, the controller 15 respectively connects the connection bar to the spare connector 24. Although it has been determined that 44U, 44V, and 44W have been changed from the arm side wirings 42U, 42V, and 42W to the attachment portions 51U, 51V, and 51W, the present invention is not limited thereto.

  In one modification (Modification 1), as shown in FIG. 5, in the first embodiment, a limit switch 61 is provided immediately adjacent to the spare connector 24. The limit switch 61 is off when any of the connection cables 9U, 9V, 9W is not connected to the spare connector 24, and any of the connection cables 9U, 9V, 9W is connected to the spare connector 24. At that time, it is pushed by the connection cable to switch to the on state.

  Moreover, in another modification (modification 2), as shown in FIG. 6, in the second embodiment, the left end portion of the motor side wirings 41U, 41V, 41W in FIG. 3 and the mounting portions 51U, 51V, 51W. Limit switches 62U, 62V, and 62W are disposed respectively. The limit switches 62U, 62V, and 62W are turned off when the connection bars 44U, 44V, and 44W are connected to the arm-side wirings 42U, 42V, and 42W, respectively. When the connection bars 44U, 44V, and 44W are connected to the mounting portions 51U, 51V, and 51W, the limit switches 62U, 62V, and 62W are pushed by the connection bars 44U, 44V, and 44W, respectively, and are turned on. Change.

  In the first embodiment, strictly speaking, since the limit switches 25U, 25V, and 25W are switched from the on state to the off state, the connection cables 9U, 9V, and 9W are disconnected from the connectors 23U, 23V, and 23W, respectively. It is possible to determine whether or not the connection cables 9U, 9V, and 9W are connected to the spare connector 24, but it is not possible to determine whether or not the connection cables 9U, 9V, and 9W are changed to the spare connector 24. Similarly, in the second embodiment, strictly speaking, since the limit switches 45U, 45V, and 45W are switched from the on state to the off state, the arm side wiring 42U of the connection bars 44U, 44V, and 44W, Although it is possible to determine whether or not the connection with 42V and 42W has been disconnected, it is not possible to determine whether or not the connection bars 44U, 44V and 44W have been changed to the attachment portions 51U, 51V and 51W.

  On the other hand, in the first modification, since the limit switches 25U, 25V, and 25W are switched from on to off and the limit switch 61 is switched from off to on, the connection cables 9U, 9V, and 9W are connected. It is possible to accurately determine whether or not the connectors 23U, 23V, and 23W are connected to the spare connector 24. Similarly, in the second modification, since the limit switches 45U, 45V, 45W are switched from on to off and the limit switches 62U, 62V, 62W are switched from off to on, the connection bars 44U, 44V, It is possible to accurately determine whether 44W has been changed from the arm side wirings 42U, 42V, 42W to the attachment portions 51U, 51V, 51W.

  In the first embodiment, the connection destination of each phase of the three-phase motor 10 is switched by switching the connection destination of the connection cables 9U, 9V, 9W to the spare connector 24. In the second embodiment, the connection bar 44U, Although the connection destination of each phase of the three-phase motor 10 is switched by switching the connection destination of 44V and 44W to the attachment portions 51U, 51V, and 51W, the present invention is not limited to this. The connection destination of each phase of the three-phase motor 10 may be switched by a configuration other than these.

1 Inverter system 9U, 9V, 9W Connecting cable 10 Three-phase motor 12U, 12V, 12W Arm 13 Spare arm 15 Controller 25U, 25V, 25W Limit switch 40 Connection switching device 45U, 45V, 45W Limit switch

Claims (1)

A three-phase motor,
Three arms respectively provided corresponding to each phase of the three-phase motor;
At least one spare arm having the same configuration as the arm;
A control device for controlling operations of the arm and the spare arm by inputting a control signal to the arm and the spare arm;
Failure arm identifying means for causing the control device to identify the failed arm when any of the three arms fails,
Each phase of the three-phase motor can be selectively connected to either the corresponding arm or the spare arm,
The control device identifies the failed arm based on the failed arm identification means, stops input of a control signal to the failed arm, and is the same control signal as is input to the failed arm Is input to the spare arm.

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