JP4876591B2 - Electric motor control method - Google Patents

Description

  The present invention relates to a method for controlling an electric motor that drives a lifting machine such as an elevator.

  In general, when a lifting machine such as an elevator is landed, a car driven by an electric motor is mechanically stopped and held by a mechanical brake by means for electrically stopping and holding by speed control by an inverter that controls the electric motor. Means for safely stopping and holding the car against falling.

  As a method for controlling the electric motor that drives such a lifting machine, for example, the one shown in FIG. 5 is known (Patent Document 1).

  FIG. 5 is a circuit diagram showing a conventional example of a control device for an electric motor that drives a lifting machine. Hereinafter, the details of the present invention will be described by taking an elevator as an example of the lifting machine.

  In the conventional circuit of FIG. 5, AC power from the commercial power source 1 is converted into AC power of variable voltage / variable frequency by the inverter 2, and the induction motor 3 uses the converted AC power at a desired torque and rotational speed. drive. The induction motor 3 is connected to an elevator 4 as a lifting machine as a load and a mechanical brake (not shown).

The speed setter 6 sets a speed set value N ^# of the rotational speed at which the induction motor 3 is to be operated and supplies the set speed to the speed command calculation circuit 7. The speed command calculation circuit 7 outputs a speed command value N ^* that changes at a predetermined speed change rate. This speed command value N ^* is finally set to a speed setting that is input to the speed command calculation circuit 7. The value matches the value N ^# . On the other hand, the speed detector 5 such as a pulse transmitter coupled to the induction motor 3 outputs the actual speed value N of the induction motor 3, and the adder 8 outputs the speed command value N ^* and the actual speed value. The deviation from N is calculated. The speed regulator 9 receives a deviation between the speed command value N ^* and the actual speed value N, and outputs a torque command calculation value τ ^** that makes the input deviation zero by the adjustment operation.

  On the other hand, the elevator 4 is provided with a counterweight on the opposite side of the wire that suspends a car carrying a person or cargo. The difference in mass between the induction motor 3 and the induction motor 3 that drives the elevator 4 varies depending on whether the car is raised or lowered. Therefore, in the elevator 4 that repeats operation / stop, each time the operation is started, the elevator load is measured, and a torque commensurate with the load that should drive the elevator 4 is set by the torque bias command setting unit 11. Is output to the torque bias command calculator 12.

When the torque bias command calculator 12 receives an operation start command from the operation command contact 14, the torque bias command calculator 12 increases the value from zero at a predetermined rate of change, and finally reaches the value set by the torque bias command calculator 12. The matching torque bias command value τ ^*** is output.

The adder 13 calculates the sum of the torque command value τ ^** output from the speed controller 9 and the torque bias command value τ ^*** output from the torque bias command calculator 12, and the total torque command as the calculation result. The value τ ^* is switched by the signal switcher 22 via the torque command calculator 21 and output to the vector control circuit 10.

The vector control circuit 10 inputs the total torque command value τ ^* and a separately obtained magnetic flux command value Φ ^*, and outputs a control signal for vector control of the inverter 2, thereby causing the induction motor 3 to have a desired torque. It can be operated at a rotational speed. Since this vector control is known, its detailed description is omitted.

FIG. 6 is a time chart showing the operation of the conventional example shown in FIG. In FIG. 6, when an operation start command is input at time t ₁ and the operation command is turned on, the elevator load is measured as described above, and the torque bias command value τ ^*** follows the rate of change from zero to A. Although it rises to a value commensurate with this measured load, the mechanical brake remains on at this time. When the mechanical brake is turned off at time t ₂ , the induction motor 3 rotates and thus the actual speed value N starts to increase, but the total torque command value τ ^* during the acceleration period up to time t ₃ is the torque bias command value τ. ^It is the sum of ^*** and torque command calculation value τ ^** . The period from t _{3 to} t _{4 is} a period in which the speed is constant, and the total torque command value τ ^* is also constant. When deceleration is started at time t ₄ , the torque command calculation value τ ^** becomes the deceleration torque in the reverse direction, so the total torque command value τ ^* becomes a small value. At time t ₅ , the mechanical brake is turned on and the induction motor 3 is stopped. However, since the operation command remains on during the period from t _{5 to} t ₆ , the total torque command value τ ^* is the torque bias command value τ ^{*. **} is output.

operation command at t ₆ time a stop command switches from ON to OFF is input, in response to this stop command, the normally open contact 22A of a signal switching device 22 switches from closed to open circuit, normally closed contact 22B is opened Switch to closed circuit. At this time, the total torque command value τ ^* output from the torque command computing unit 21 is decreased at a rate of change B by the action of the torque command computing unit 21, so that the mechanical brake is already in the ON state at this time. However, the generation of noise is suppressed.
JP 2003-26375 A

In the above-described prior art, in the state where the mechanical brake is applied at the time of start-up and deceleration, the total torque command value τ ^* is increased or decreased at a predetermined rate of change so that the total torque command value τ ^* changes rapidly. Since it is suppressing, generation | occurrence | production of noise can be suppressed.

However, the torque is gradually increased from a state in which the car speed is zero with the mechanical brake applied to a value set by the torque bias command setter 11 at a predetermined rate of change, or stopped while the mechanical brake is applied. In this case, since the total torque command value τ ^{* is} attenuated to zero at a predetermined change rate, it takes time to complete the torque change. For this reason, there will be extra time from when the elevator floor movement is commanded until the elevator actually starts moving until the elevator stops and the electrical stop is no longer maintained. There was an inconvenience that would cause discomfort.

  The present invention solves the above-described inconveniences, and an object of the invention is to shorten elevator start / stop time while suppressing generation of noise.

In order to achieve the above object, a method for controlling an electric motor according to the present invention includes a speed command calculation circuit that outputs a speed command value according to a predetermined speed change rate from a speed set value set in a speed setter, and a lifting machine. A speed detector that outputs an actual speed value of the motor to be driven, a speed regulator that calculates a torque command value from a deviation between the speed command value and the actual speed value, and a torque that is commensurate with a load that moves the lifting machine up and down A torque bias command calculator for outputting a bias command value; and an adder for adding the torque command value and the torque bias command value. The motor is torque controlled based on a total torque command value as a result of the addition. In the motor control method,
When an operation start command for the electric motor is input, a total torque command value of a first predetermined value is given stepwise, and thereafter the total torque command value is increased at a first rate of change.

  In the above, when a stop command is input, the total torque command value is reduced to the second predetermined value at the second rate of change, and thereafter the total torque command value is made zero stepwise.

  When an attenuation start signal provided separately from the stop command is input, the total torque command value is reduced to the second predetermined value at the second rate of change, and then the total torque command value is set until the operation command is canceled. It is to hold.

  According to the present invention, in a state where the car speed of the elevator where the mechanical brake is applied is zero, an arbitrary torque bias is first given stepwise without a change rate, and then increased at a predetermined change rate. . Also, after reducing the total torque command value at a predetermined rate of change from the total torque command value when the mechanical brake is stopped and holding to a desired torque value, the total torque command value is stepped to zero without the rate of change. To do. By doing in this way, while suppressing generation | occurrence | production of noise, the operation time of starting and a stop will be shortened, and the discomfort to the passenger of an elevator can be improved.

  FIG. 1 is a circuit diagram showing a first embodiment of the present invention. Components having the same functions as those of the conventional example shown in FIG. That is, in FIG. 1, instead of the torque bias command calculator 12, torque command calculator 21, signal switching unit 21, normally open contact 22A, and normally closed contact 22B of the conventional circuit, the first torque bias command calculator 32 is used. The first torque command calculator 33, the signal switch 34, the normally open contact 34A, and the normally closed contact 34B are different.

In such a configuration, when an operation start command is input to the first torque bias command calculator 32, a torque commensurate with the load to drive the elevator 4 is set by the torque bias command setter 11, and the torque bias For the command value τ ^*** , first, a command value of a first predetermined value is given stepwise, then the command value is increased at a predetermined first change rate, and finally the first torque bias command calculation is performed. Torque bias command value τ ^*** that matches the value set in the device 32 is output. When a stop command is input, the first torque command calculator 33 first reduces the total torque command value τ ^* to a second predetermined value at a predetermined second change rate, and then from the second predetermined value. The total torque command value τ ^{* is set} to zero in a stepwise manner.

  Here, the first predetermined value and the second predetermined value are arbitrary values between a value set by the first torque bias command calculator 12 and zero (for example, the first torque bias command calculator 12 is set). (About 50% of the value) is set in advance, but the amount of the first predetermined value and the second predetermined value is determined according to the load.

  The first change rate and the second change rate are determined by arbitrarily setting the time required for the change, and the first change rate is calculated from a first predetermined value based on a first torque bias command calculation. The time required for the device 12 to change to the set value (for example, about 0.5 s) is set in advance, and the second rate of change is a second predetermined value from the value set by the first torque bias command calculator 12. The time required to change to the value (for example, about 0.5 s) is set in advance.

FIG. 2 is a time chart showing the operation of the first embodiment. In FIG. 2, when an operation start command is input at time t ₁₁ and the operation command is turned on, a torque commensurate with the load to drive the elevator 4 is set by the torque bias command setting device 11, and this is set as the first torque. Output to the bias command calculator 32. The torque bias command value τ ^*** is first output as a stepwise bias value C (first predetermined value) without a change rate, and then rises to a value commensurate with this measured load according to the change rate D. . Although the state of the mechanical brake is still ON at t ₁₁ time, even if the total torque command value tau ^* to the first predetermined value stepwise at t ₁₁ the time, since the torque generated by the induction motor 3 is sufficiently small, Generation of noise from the mechanical brake at the start of operation is suppressed.

Although t induction motor 3 and the mechanical brake is turned OFF at the ₁₂ time starts increasing the speed actual value N so rotated, the total torque command value tau ^* is in the acceleration period until t ₁₃ time, the torque bias command value tau ^It is the sum of ^*** and torque command calculation value τ ^** . period t ₁₃ ~t ₁₄ is a constant speed period, a total torque command value tau ^* also constant. When you start decelerating at t ₁₄ the time, since the torque command calculation value tau ^** the deceleration torque in the reverse direction, ^* the total torque command value tau is a small value. While stopping the induction motor 3 the mechanical brake is turned on at t ₁₅ the time, since the operation command during a period of t ₁₅ ~t ₁₆ remains on, the total torque command value tau ^* is torque bias command value tau ^{* **} is output.

When operation command at t ₁₆ time switches from ON to OFF stop command is input, this corresponds to the stop command, normally open contact 34A of the signal switching unit 34 is switched from closed to open circuit, normally closed contact 34B is opened Switch to closed circuit. At this time, the total torque command value τ ^* output from the first torque command calculator 33 is first reduced to a second predetermined value at a rate of change E by the action of the first torque command calculator 33, and thereafter , The total torque command value τ ^{* is set} to zero in a step shape of F at time t ₁₇ . As Although the mechanical brake at t ₁₇ when in the ON state, since the torque generated by the induction motor 3 is sufficiently small, and to zero stepwise total torque command value tau ^* without change rate at t ₁₇ time However, the generation of noise from the mechanical brake when stopped is suppressed.

  FIG. 3 is a circuit diagram showing a second embodiment of the present invention. Components having the same functions as those of the first embodiment shown in FIG. . That is, in FIG. 3, instead of the first torque command computing unit 33, the signal switching unit 34, the normally open contact 34A and the normally closed contact 34B of FIG. 1, the second torque command computing unit 43, the signal switching unit 44, The difference is that a closed contact 44A and a normally open contact 44B are provided.

In such a configuration, when the attenuation start signal provided separately from the stop command is input, the second torque command calculator 43 first calculates the total torque command value τ ^* at the predetermined second change rate. 2 After the value is reduced to a predetermined value, the total torque command value τ ^* is held at the second predetermined value until the operation command is released. After that, when the operation command is released and a stop command is input, The total torque command value τ ^{* is set} to zero in steps from a predetermined value.

Figure 4 is a time chart showing the operation of the second embodiment, from t ₂₁ time t to ₂₆ times, because it is the same as the ₁₁ time points indicated in FIG. 2 to t ₁₆ time, the Description is omitted.

When an attenuation start command provided separately from the stop command is input at time t ₂₆ , the normally closed contact 44 A of the signal switching unit 44 is switched from closed to open in response to the attenuation start command, and the normally open contact 44 B is Switch from open to closed. In this case the total torque command value tau ^* is output from the second torque command calculator 43, reducing its value E becomes the rate of change by the action of the second torque command calculator 43, then, t ₂₈ from t ₂₇ time Since the operation command is not released until the time point, the total torque command value τ ^* is held at the second predetermined value G. When the operation command is switched from ON to OFF at time t ₂₈ and a stop command is input, the total torque command value τ ^* is set to zero without a change rate in a step shape of F. Although the mechanical brake is in the ON state at time t ₂₈ , the torque generated by the induction motor 3 is sufficiently small. Therefore, it is assumed that the total torque command value τ ^* is set to zero without a change rate at time t _28. However, the generation of noise from the mechanical brake when stopped is suppressed.

The circuit diagram which showed the 1st Embodiment of this invention Time chart showing the operation of the first embodiment The circuit diagram which showed the 2nd Embodiment of this invention Time chart showing the operation of the second embodiment Circuit diagram showing a conventional example Time chart showing the operation of the conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Inverter 3 Electric motor 5 Speed detector 9 Speed regulator 10 Vector control circuit 11 Torque bias command setting device 32 1st torque bias command calculator 33 1st torque command calculator 43 2nd torque command calculator

Claims (3)

A speed command calculation circuit that outputs a speed command value from a speed set value set in the speed setter according to a predetermined rate of change in speed, a speed detector that outputs an actual speed value of an electric motor that drives the lifting machine, and the speed A speed regulator that calculates a torque command value from a deviation between the command value and the actual speed value; a torque bias command calculator that outputs a torque bias command value corresponding to a load for raising and lowering the lifting machine; and the torque command value And an adder for adding the torque bias command value, and a motor control method for torque controlling the motor based on the total torque command value as a result of the addition,
When an operation start command for the motor is input, a total torque command value of a first predetermined value is given in a stepwise manner, and then the total torque command value is increased at a first rate of change. . The method for controlling an electric motor according to claim 1,
When a stop command is input, the total torque command value is reduced to a second predetermined value at a second rate of change, and thereafter the total torque command value is set to zero in a stepwise manner. The method for controlling an electric motor according to claim 1,
When an attenuation start signal provided separately from the stop command is input, the total torque command value is decreased to the second predetermined value at the second rate of change, and thereafter the total torque command value is held until the operation command is canceled. A method for controlling an electric motor.

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