JPH0472475B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is directed to a motor control device using a thyristor Leonard device or an inverter device, in particular, a method for free-running the motor to perform coasting (hereinafter referred to as coasting) operation. This invention relates to a coasting operation control device.

[Technical background of the invention and its problems] In recent years, with the advent of power conversion elements and microcomputers due to advances in semiconductor technology, thyristor Leonard devices and inverter devices have become popular as control devices for electric motors used in cranes, etc. It is beginning to be widely used due to its excellent performance. On the other hand, in order to prevent the suspended load from swinging when the crane is running, so-called coasting operation is used, in which the electric motor is allowed to free-run when decelerating during running to smoothly decelerate due to mechanical loss in the running system. It is often done.

However, there is currently no motor control system that uses the above-mentioned thyristor Leonard device or inverter device that has a coasting function in its control system, and there is a problem in that the above-mentioned coasting operation cannot be performed.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and its purpose is to eliminate coasting operation of an electric motor driven by a thyristor Leonard device or an inverter device, and to solve the problem from coasting operation. An object of the present invention is to provide a coasting operation control device that can smoothly switch to normal operation.

[Summary of the Invention] In order to achieve the above object, the present invention provides a motor control device using the above-mentioned thyristor Leonard device or inverter device with a coasting function, and when there is no coasting command, the speed reference signal is accelerated or decelerated by an analog switch. input to the limit circuit,
The speed control amplifier generates a torque reference signal based on the deviation between the actual speed reference signal, which is the output of the acceleration/deceleration limiting circuit, and the speed feedback signal, and controls the motor during normal operation. At times, the output of the speed control amplifier is reduced to zero by a limiter regardless of the input of the speed control amplifier, and the torque generated by the motor is set to zero and the motor is allowed to run free, while at the same time, when switching from coasting command presence to no coasting command, the acceleration/deceleration limiting circuit is With a coasting command, the proportional integral time of the acceleration/deceleration limiting circuit is reduced to practically zero so that the actual speed reference signal that is the output starts from the same standard as the motor free running speed immediately before the coasting command is issued. function as if it were a proportional amplifier, and selectively input a speed feedback signal to the acceleration/deceleration limiting circuit in this state using an analog switch to generate an actual speed reference signal, which is the output of the acceleration/deceleration limiting circuit while a coasting command is in progress. is always set to the same standard as the motor speed in the free running state.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows in block form an example of the configuration of a coasting operation control device according to the present invention. In the figure, 1 is a controller that provides a speed reference signal A, 2 is a first analog switch that inputs a speed feedback signal B of a motor (not shown) and becomes conductive when coasting command C is present, and 3 is a switch that receives the speed reference signal. This is a second analog switch which receives A as an input and becomes conductive when there is no coasting command C. 4 is the first and second
This is an acceleration/deceleration limiting circuit that receives the output signals of analog switches 2 and 3 as input, and operates at an appropriate proportional integral time without the coasting command C, and with the coasting command C, the proportional integral time is short enough for practical use. The output signal becomes zero, and the output signal is outputted as the actual speed reference signal D. Further, 5 is a speed control amplifier that generates a torque reference signal E from the deviation signal between the actual speed reference signal D and the speed feedback signal B detected by the deviation detector 6, and 7 is the speed control amplifier 5.
This is a limiter that limits the torque reference signal E, which is the output of the torque reference signal E, to zero when a coasting command C is present.

Next, the operation of such a coasting operation control device will be described.

First, when there is no coasting command C, the second
The analog switch 3 inputs the speed reference signal A from the controller 1 to the acceleration/deceleration limiting circuit 4, and based on the deviation between the actual speed reference signal D, which is the output of the acceleration/deceleration limiting circuit 4, and the speed feedback signal B, speed control is performed. A torque reference signal E is generated by amplifier 5.
The electric motor (not shown) is controlled during normal operation and is operated at a speed based on the speed reference signal A from the controller 1.

Next, when the coasting command C becomes valid while the motor is operating at this speed, the output of the speed control amplifier 5 is reduced to zero by the limiter 7, the torque reference signal E becomes zero, and the motor stops. Free run.

On the other hand, due to the presence of the coasting command C, the first
The analog switch 2 becomes conductive, and the speed feedback signal B, that is, the free run speed of the motor, is input to the acceleration/deceleration limiting circuit 4 instead of the speed reference signal A. At this time, the acceleration/deceleration limiting circuit 4 becomes a proportional amplifier whose proportional integral time is practically zero due to the existence of the coasting command C, so that the actual speed reference signal D that is its output becomes the same reference as the motor free run speed. .

Next, when the coasting command C is switched from present to absent, the second analog switch 3 inputs the speed reference signal A from the controller 1 to the acceleration/deceleration limiting circuit 4 in place of the speed feedback signal B. . At this time, the acceleration/deceleration limiting circuit 4 operates as a proportional-integral amplifier with an appropriate proportional-integral time due to the absence of the coasting command C, but as described above, the acceleration/deceleration limiting circuit 4 operates until just before the coasting command C is Since the actual speed reference signal that is the output follows the motor free run speed, the acceleration/deceleration limiting circuit 4 is applied regardless of the value of the speed reference signal A from the controller 1.
starts the proportional-integral operation with this motor free-run speed as the initial value, changes the actual speed reference signal D in a ramp-like manner up to the value set by the speed reference signal A of the controller 1, and changes the coasting command C from presence to absence. The switching will be performed smoothly.

That is, FIG. 2 shows the operation of the acceleration/deceleration limiting circuit 4. As shown in FIG. In the figure, between t _A and t _C ,
The period from t _D to t _E indicates that the coasting command C is not present, and the period from t _C to t _D indicates that the coasting command C is present.

Now, when the speed reference signal A is input to the acceleration/deceleration limiting circuit 4 between _tA and _tC , the actual speed reference signal D
is _determined by the proportional-integral operation of the acceleration/deceleration limiting circuit 4.
The output ramps up to a value _D1 corresponding to the value of the speed reference signal A between tB _and tB, and the constant output _D1 is maintained as between _tB and _tC unless the speed reference signal A changes.
Next, between t _C and t _D , when the coasting command C becomes valid at time t _C , the input of the acceleration/deceleration limiting circuit 4 is switched to the speed feedback signal B by the first analog switch 2, and the acceleration/deceleration limiting circuit 4 is switched to the speed feedback signal B by the first analog switch 2. Since the proportional integral time of the circuit 4 becomes practically zero and operates as a proportional amplifier, the actual speed reference signal D follows the motor free run speed. Furthermore, between t _D and t _E ,
When the coasting command C becomes null at time _tD , the second
The analog switch 3 inputs the speed reference signal A to the acceleration/deceleration limiting circuit 4 again, and the acceleration/deceleration limiting circuit 4 again performs the proportional-integral operation, so that the actual speed reference signal D matches the value of the speed reference signal A. value
It will change like a ramp to D ₂ or D ₃ .

As described above, the coasting operation control device of the present invention inputs the speed reference signal A and the speed feedback signal B of the variable machine driven by the thyristor Leonard device and the inverter device, and when the coasting command C is not issued, the speed reference signal A and the speed feedback signal B are input. When the coasting command C is present, the signal A is also used as the speed feedback signal B.
The first and second
analog switches 2 and 3 and the output signal from each analog switch 2 or 3 are input, and when there is no coasting command C, the proportional integral operation is performed at the appropriate proportional integral time, and when the coasting command C is present, the proportional integral operation is performed at the appropriate proportional integral time. Torque is determined from the output signal of an acceleration/deceleration limiting circuit 4 that performs proportional operation with the acceleration/deceleration limiting circuit set to approximately zero, and a deviation detector 6 that detects the deviation between the actual speed reference signal D, which is the output of this acceleration/deceleration limiting circuit, and the speed feedback signal B. a speed control amplifier 5 generating a reference signal E;
A limiter 7 limits the torque reference signal E, which is the output of the speed control amplifier 5, to approximately zero when the coasting command C is present.

Therefore, by equipping a thyristor Leonard device or an inverter device with a coasting function, it is now possible to achieve coasting operation, which was previously impossible, and to reduce the speed gap when switching from coasting operation to normal operation. Switching can be performed smoothly without causing any problems, and an extremely reliable device can be obtained.

[Effects of the Invention] As explained above, according to the present invention, the coasting operation of the electric motor driven by the inverter device or the thyristor Leonard device and the switching from the coasting operation to the normal operation can be smoothly performed. A highly reliable coasting operation control device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram for explaining the operation of the acceleration/deceleration limiting circuit 4 in FIG. 1. 1... Controller, 2, 3... Analog switch, 4... Acceleration/deceleration limiting circuit, 5... Speed control amplifier, 6... Deviation detector, 7... Limiter.

Claims (1)

[Claims] 1 In a thyristor Leonard device, which performs coasting operation by free-running a motor driven by an inverter device, the speed reference signal and speed feedback signal of the motor are input, and when there is no coasting command, the speed reference signal is also used for coasting. When there is a command, an analog switch selectively outputs the speed feedback signal, and the output signal from this analog switch is input, and when there is no coasting command, proportional integral operation is performed at an appropriate proportional integral time, and when there is a coasting command, the proportional integral operation is performed. an acceleration/deceleration limiting circuit that performs proportional operation with a proportional integral time of approximately zero, and a speed control amplifier that generates a torque reference signal from a deviation signal between an actual speed reference signal that is an output of the acceleration/deceleration limiting circuit and the speed feedback signal. and a limiter that limits the torque reference signal, which is the output of the speed control amplifier, to approximately zero when the coasting command is present.