JP2635759B2 - Control device for elevator with reduction gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention obtains an electric motor for driving an elevator car as a difference between a car load and a counterweight according to a speed reference from a speed command generating means. The present invention relates to a control device for an elevator with a speed reducer, which performs operation control while adding a first unbalanced torque compensation amount due to a given unbalanced load.

(Prior Art) FIG. 3 shows a general elevator control device. In the elevator of FIG. 3, a main rope 3 is hung on a rope wheel 2 with a speed reducer driven by an electric motor 1, an elevator car 4 is attached to one end of the main rope 3, and a counterweight 5 is attached to the other end. Have been. The rope wheel 2 is provided with a brake 6 that operates when stopped. The motor 1 is provided with a speed detector 7 for detecting the rotation speed 7a of the motor 1, and the elevator car 4 detects an unbalanced load 8a between the elevator car 4 and the counterweight 5. A vessel 8 is provided.

The rotation speed of the electric motor 1 detected by the speed detector 7
7a is a speed command generated by the speed command generator 9.
It is input to the speed controller 10 together with 9a, where a current reference 10a for matching the former (rotation speed 7a) to the latter (speed command 9a) is given to the current controller 11. The current controller 11 determines the current based on the current reference 10a from the speed controller 10, the current 12a of the motor 1 detected by the current detector 12, and the unbalanced load 8a detected by the unbalanced load detector 8. 12
An operation signal 11a is generated so as to match a with the current reference 10a corrected by the unbalanced load 8a, and the current of the electric motor 1 is controlled via the power converter 13.

FIG. 4 shows a more detailed circuit configuration of the speed controller 10. The speed controller 10 has four sets of operational amplifiers 15 to
Contains 18 The operational amplifier 15 constitutes a summing amplifier together with the operational resistors 19 to 21, and similarly, the operational amplifier 16 constitutes a proportional control amplifier P together with the operational resistors 22 to 23, and the operational amplifier 17 together with the operational resistor 24 and the integrating capacitor 25. The operational amplifier 18 constitutes an addition amplifier together with the operational resistors 26-28. A disconnecting switch 29 for holding the integral amount is connected in series to the operational resistor 24 of the integral control amplifier I, and a clear switch 30 for clearing the same is connected to the integrating capacitor 25 in parallel. ing. The proportional control amplifier P and the integral control amplifier I constitute a proportional integral controller, that is, a PI controller.

With the above configuration, the deviation between the actual speed 7a and the speed reference 9a, that is, the speed deviation, is calculated by the operational amplifier 15, and based thereon, the PI operation is performed by the proportional control amplifier P and the integral control amplifier I, and the outputs of both are calculated. The signals are added by the amplifier 18 and the sum is output as the current reference 10a.

(Problems to be Solved by the Invention) By the way, in order for a generally stationary object, including an elevator, to start moving, it must be added to a torque object that overcomes the load torque of the object. Here, the load torque includes a friction torque corresponding to a friction force acting between an object to be moved and another object with which the object is in contact. There are two types of friction: static friction acting on the interwinding of a stationary object, and dynamic friction acting between relatively moving objects. Generally, static friction is larger than dynamic friction. Further, among the static frictions, the maximum frictional force immediately before the object starts moving is called the maximum static friction. In order to move a stationary object, it is sufficient to consider the maximum static friction force and apply a torque exceeding the load torque including the maximum static friction force, whereby the object gradually starts accelerating. Once you start moving,
The dynamic friction shifts to a smaller value, and the friction torque in the load torque decreases.

When considering the activation of an elevator equipped with a speed reducer, the frictional force increases by the amount of the speed reducer compared to the case without the speed reducer,
In order for the elevator to move in accordance with a speed command value having a constant acceleration, a larger driving torque is required as compared with a case without a speed reducer.

However, in the control device shown in FIG.
Is configured to include a PI controller as shown in FIG. 4, the starting torque that overcomes the load torque including the friction torque corresponding to the static friction with respect to the input speed designation value 9a is expressed by the electric motor 1. The motor speed 7a detected by the speed detector 7, that is, the speed feedback amount is zero immediately before the start, and the integral control amplifier I determines that the motor speed 7a is equal to the speed reference 9a immediately before startup.
The input signal is integrated until it becomes equal to The integration time constant at this time is determined by a preset integration time constant.

This value is generally large enough for a change in torque required for the elevator to accelerate smoothly. For this reason, at the time of starting, the elevator is operated with an unnecessarily large starting torque, which involves a large start shock.

The acceleration of the elevator that has started to move with the large starting torque described above is large, and is sufficiently faster than the set speed response of a general speed control system. For this reason, it is difficult to suppress the movement of the elevator at the time of startup by the control system, and large acceleration vibration is accompanied. FIG. 5 shows a time chart of the speed command value 9a, the motor speed (speed feedback) 7a, the current reference 10a, and the vibration S of the elevator car 4 at this time. Since the integral control amplifier I included in the speed controller 10 integrates the input speed command value 9a until the elevator starts moving, the control system cannot cope with a sudden change at the time of starting.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for an elevator with a speed reducer suitable for suppressing acceleration vibration caused by a sudden decrease in load torque due to a decrease in friction torque at the time of startup in an elevator with a speed reducer.

[Configuration of the invention]

[Means for Solving the Problems] In order to achieve the above object, a control device for an elevator with a speed reducer according to the present invention is adapted to handle a deviation between a first unbalanced torque compensation amount and an amount corresponding to an actual speed of an electric motor. First means for obtaining a second torque compensation amount to be performed, second means for detecting when the motor speed reaches a predetermined value at the time of starting the elevator, and motor speed being predetermined by the second means at the time of starting the elevator. A second means for correcting the first torque compensation amount by a second unbalanced torque compensation amount within a range until the value is detected.

(Operation) A sudden decrease in friction torque at startup is detected by an unbalanced load detector provided in the elevator car, and this is used as a signal for compensating for a sudden decrease in friction torque at startup, and an unbalanced torque signal and a speed feedback signal are used. Is added to the unbalanced torque signal and controlled only when the elevator is started.
At this time, the deviation signal to be added is controlled so as to become zero when the speed feedback signal exceeds the unbalanced torque signal, and the polarity thereof is determined by the polarity of the unbalanced torque signal and the operation direction of the elevator. Switching control for torque compensation 2 is performed. By doing so, it is possible to suppress the influence of a sudden decrease in friction torque at the time of starting, and to achieve smooth starting without acceleration vibration.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the elevator apparatus of FIG. 1, similar to that of FIG. 3,
A main rope 3 is hung on a rope wheel 2 with a speed reducer driven by an electric motor 1, an elevator car 4 is attached to one end of the main rope 3, and a counterweight 5 is attached to the other end. The electric motor 1 is assumed to be composed of an induction motor. The rotation speed 7a of the electric motor 1 is detected by the speed detector 7, and the rotation speed 7a
Is detected by the unbalanced load detector 8, and the motor current 12 a is detected by the current detector 12.

The speed controller 10 receives the speed reference 9a generated by the speed command generator 9 and the motor speed 7a detected by the speed detector 7, and provides a torque reference 10a that reduces the difference between the two inputs to zero. Is output. This torque reference 10a is input to a first input terminal of the adder 31.

Unbalanced load 8a detected by unbalanced load detector 8
Polarity, that is, with its equilibrium load as the center (0),
Negativeness is determined by the polarity determination circuit 32, and a polarity determination signal 32a is input to the polarity switching circuit 33. Here, the polarity of the negative balanced load 8a is determined as follows by comparing the load of the car 4 with that of the counterweight 5.

If the car load is large ... negative If the car load is small ... positive The motor speed 7a is input to one end of the differential amplifier 36 via the absolute value circuit 34 and the signal conversion circuit 35, and the unbalanced load 8a is the absolute value circuit. The signal is input to the other end of the differential amplifier 36 via 37. The differential amplifier 36 is an amplifier for adjusting the compensation amount of the start compensation signal, calculates the difference between the two inputs, and sends it to the polarity switching circuit 33 via the coefficient unit 38 as a start compensation signal. When the motor speed 7a converted into a signal via the signal conversion circuit 35 exceeds the unbalanced torque load, the output signal of the differential amplifier 36 is clamped to zero. The polarity switching circuit 33 is provided with a polarity determination signal 32 from the polarity determination circuit 32.
a, and the driving direction command signal from the elevator driving direction command circuit 39 is input, and the polarity of the start compensation signal (abbreviated as a compensation signal) from the coefficient unit 38 is switched based on the inputted next decision logic. Here, for convenience of explanation, it is shown together with the polarity of the torque reference 10a output from the speed controller 10.

Load negative, rise… Negative torque reference, compensation signal negative Load negative, fall… Negative torque reference, compensation signal positive Load positive, rise… Torque reference positive, compensation signal negative Load positive, fall… Tokuru reference positive, compensation signal positive coefficient unit 38 performs an adjusting operation in accordance with a change in friction torque characteristics at the time of starting the elevator. The absolute speed value output from the absolute value circuit 34 is monitored by a speed level detection circuit 40, and when it reaches a predetermined value or more, the speed level detection signal 40
a is output. A start compensation disconnection circuit 41 is provided on the output side of the polarity switching circuit 33, and the startup compensation is performed literally only at the time of startup, and when the startup is completed, the compensation disconnection circuit is provided.
By 41, the start compensation is separated. The start compensation disconnection circuit 41 receives the speed level detection signal 40a from the speed level detection circuit 40 and the operation command signal 42a from the elevator operation command generation circuit 42, and after the elevator is started, the speed increases to a predetermined level. When the speed is exceeded and the speed level detection signal 40a is output, a start compensation signal 41a is output. The start compensation signal 41a is input to the adder 43, where it is added to the unbalanced load signal 8a and output as a combined compensation signal 43a. This combined compensation signal 43a is input to the adder 31 as a second input signal, and is added to the torque reference 10a.
The output signal of the adder 31 is converted to a current reference 44a via a vector control circuit 44 as a corrected torque reference 31a and input to the current controller 11. The current controller 11 controls the motor current via the PWM control circuit 45 and the voltage type inverter 46 so that the motor current 12a detected by the current detector 12 matches the current reference 44a from the vector control circuit 44.

Next, the operation of the apparatus of FIG. 1 will be described with reference to the time chart of FIG.

Suppose now that a passenger enters the elevator car 4 in a fully loaded state (full load state) and drives in the ascending direction. This load state is detected by the unbalanced load detector 8 and is output as an unbalanced load 8a having a negative (minus) polarity. The polarity of the unbalanced load 8a is determined by the polarity determination circuit 32, and the polarity switching circuit 33 determines the polarity of the start compensation signal in consideration of the operation direction command signal 39a from the operation direction command circuit 39. That is, in this case, since the unbalance load is negative and the operation is ascending, the polarity of the start compensation signal becomes “positive” according to the above-described determination logic. Assuming that the value of the torque reference 10a from the speed controller 10 is A, the motor speed 7a immediately after the start is zero, and therefore, immediately after the start, the gain of the coefficient unit 38 is K and the value (A + M · A) is obtained. Is output. When a start signal is output and speed control is started according to the speed reference 9a and the elevator starts moving, the motor speed 7a fed back to the speed controller 10 gradually increases accordingly. In addition,
Generally, the load torque at the time of starting to start from a stopped state is a non-linear and complicated one, but here, it is assumed that the load torque is linear, and the amount of compensation is reduced according to the speed. Differential amplifier 36 as motor speed 7a increases
The difference between the two inputs gradually decreases. At this time, how to reduce the start compensation signal depends on the motor 1,
It changes depending on the type of the hoist constituted by the rope wheel with speed reducer 2 and the main rope 3 and the load, and is adjusted by adjusting the gain of the coefficient unit 35.

When the control process further proceeds and the elevator speed, that is, the motor speed 7a increases to a predetermined value, the speed level detection circuit 40 outputs a speed level detection signal 40a, and the start compensation disconnection circuit 41 disconnects the start compensation circuit. Thereafter, the process shifts to normal torque control by normal speed control. This start compensation disconnection can be similarly realized by a deceleration command or another operation control signal.

As described above, according to the present invention, a sudden change in friction torque at startup in an elevator with a speed reducer is corrected as a compensation control signal at startup to the speed reference from the speed controller, so that a large value is obtained at stop. By outputting the compensation amount and reducing it as a function of speed once it starts moving, it is possible to perform compensation control appropriately corresponding to a change in friction torque at the time of starting.

In addition, the amount of compensation can be adjusted according to the change of the friction torque of the system at the time of starting including the hoist, and the amount of compensation can be adjusted, and the optimum torque adjustment according to the system can be performed here. it can.

Furthermore, the above-mentioned torque change is a problem only at the time of starting,
By disconnecting the compensation circuit after the start-up, no extra control signal is added at the time of stop.

〔The invention's effect〕

According to the present invention, a sudden change in friction torque at startup in an elevator with a speed reducer is corrected as a compensation control signal at startup to the speed reference from the speed controller to output a large compensation amount at stop. Also, once it starts moving, by reducing it as a function of speed, it is possible to appropriately cope with a change in friction torque at the time of starting, and to achieve smooth starting without acceleration vibration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the apparatus of FIG. 1,
FIG. 3 is a block diagram of a conventional elevator control device, FIG. 4 is a circuit connection diagram showing an internal configuration of a speed controller in the control device of FIG. 3, and FIG. 5 shows an operation mode of the device of FIG. FIG. 4 is a signal waveform diagram for explaining. 1 ... electric motor, 2 ... rope car with reduction gear, 3 ... main rope, 4 ... elevator car, 5 ... counterweight,
7 Speed detector, 8 Unbalanced load detector, 9 Speed command generator, 10 Speed controller, 11 Current controller, 12 Current detector, 31, 43 Adder, 32: Polarity discriminating circuit, 33: Polarity switching circuit, 34, 37 ... Absolute value circuit, 35, 38 ... Coefficient unit, 36: Differential amplifier, 39: Operating direction command circuit, 40 ... speed level detection circuit, 41 ... compensation disconnection circuit, 42 ... operation command generation circuit, 43 ... adder,
46 …… Voltage-type inverter.

Claims (1)

(57) [Claims] An operation control of an electric motor for driving an elevator car according to a speed reference from a speed command generating means while adding a first unbalanced torque compensation amount by an unbalanced load obtained as a difference between a car load and a counterweight. A first means for determining a second torque compensation amount corresponding to a deviation between the first unbalanced torque compensation amount and an amount corresponding to an actual speed of the electric motor, A second means for detecting when the motor speed reaches a predetermined value at the time of starting, and a motor for detecting that the motor speed has reached the predetermined value by the second means at the time of starting the elevator. First
And a second means for correcting the torque compensation amount by the second unbalanced torque compensation amount.