JP3255839B2 - AC elevator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved AC elevator control device for controlling an elevator speed by driving an induction motor with a general-purpose inverter.

[0002]

2. Description of the Related Art At present, inverter devices are widely used to control an AC motor such as an induction motor or a synchronous motor at a variable speed. Recently, among these inverter devices, what is generally called “general-purpose inverter”
The application range is being expanded by the high performance and high functionality accompanying the recent performance improvement of switching elements and microprocessors.

As a control method for this general-purpose inverter, V / f control has been widely adopted. V / f control is an open-loop control method, and there is no need to detect the rotation speed of the electric motor. For this reason, even in the case of an existing AC motor, it is not necessary to attach a speed detector to the motor, and variable speed operation is possible by simply connecting a general-purpose inverter between the AC power supply and the motor. Therefore, if speed control is performed using this general-purpose inverter without a speed sensor,
Since the trouble of mounting the speed detector can be omitted, a simple control configuration can be realized, and the cost merit is great, it can be applied to the speed control of the elevator.

In this general-purpose inverter, a speed pattern is generated by a preset acceleration / deceleration inside the inverter. In addition, in order to obtain a smoother speed pattern, the speed is determined by a trapezoidal wave acceleration / deceleration pattern. Is generally provided.

In general-purpose inverters without a speed sensor, variations in speed occur due to variations in load. Therefore, the inverters are provided with a function of estimating the load by detecting current and compensating for variations in speed. In order to perform a load estimation calculation using this function, it is necessary to set a motor constant. Therefore, this general-purpose inverter
Motor constant calculation mode is pre-installed, and if the motor constant calculation mode is selected from the outside with the inverter and motor connected, the current will automatically flow to the motor,
It also has a function to calculate the motor constant based on the detection signal.

[0006]

When elevator speed control is performed using a general-purpose inverter that changes the speed in accordance with the trapezoidal wave acceleration / deceleration pattern, a change in torque at a portion corresponding to the corner of the trapezoidal wave is caused by a car. Transmitted to the vehicle, deteriorating ride comfort. Therefore, when this general-purpose inverter is applied to an elevator, it is not sufficient to make the speed command a trapezoidal wave acceleration / deceleration speed pattern, and it is necessary to make the speed command smoother.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem.
The purpose of the present invention is to make the acceleration / deceleration pattern of a general-purpose inverter smoother and to improve the riding comfort when applied to an elevator.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a speed command generating means for outputting a speed pattern of trapezoidal wave acceleration / deceleration as a speed command, and a general-purpose inverter internally provided with a motor constant calculating means. In a control device of an AC elevator performing control, a filter is inserted after the speed command generating means, and a filter time constant setting for automatically setting a time constant of the filter by using a calculation result of the motor constant calculating means. Means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a filter as a first-order lag element is inserted at the subsequent stage of a speed command generating section so that a speed command becomes even smoother. Improves ride comfort at the corners. Further, the filter time constant is automatically set to an appropriate value by a filter time constant setting unit by using a calculation result of a motor constant calculation function provided in advance therein.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing one embodiment of the first invention of the present application.

In FIG. 1, 1 is a three-phase AC power supply, 2 is a converter for converting an AC power supply to DC, 3 is a smoothing capacitor for smoothing the output of this converter, and 4 is a converter 2
An inverter for converting the output of the inverter into an alternating current having a variable voltage and a variable frequency; 5 a current detector for detecting the output current of each phase of the inverter 4; 6 an induction motor fed by the inverter 4 to drive the elevator; and 7 an induction motor 6 8 is a main rope wound around the sheave 7;
9 is a car connected to the main rope 8, 10 is a counterweight, 11 is an inverter control device composed of a microcomputer, 12 is a speed command generator for generating a predetermined speed command signal 12a, and 13 is a speed command signal. A frequency command converter for converting 12a into an inverter output frequency command 13a, a filter 14 as a first-order lag element, and a slip frequency 15 for outputting a compensation amount according to the motor load from the inverter output current as a slip frequency command 15a. Arithmetic unit,
Reference numeral 16 denotes a motor constant calculation unit which automatically supplies a current to the motor when the motor constant calculation mode is selected from the outside and calculates a motor constant based on a detection signal at that time;
Is a filter time constant setting unit that calculates and sets an optimal time constant of the filter from the motor constant calculated by the motor constant calculation unit. 18 is a filter time constant 13a and a slip frequency command 15a that are added through the filter and input. The required inverter operating frequency and voltage are calculated, and the PWM
A voltage / frequency calculation unit for generating a signal, 19 is a PWM
This is a base drive circuit that controls a switching element such as a transistor constituting an inverter by a signal.

The operation of the present invention in the above configuration will be described. When an elevator operation start command (not shown) is input to the inverter control device 11, a speed command 12 a is output from the speed command generator 12, and is converted into a frequency command 13 a by the frequency command converter 13. By passing this frequency command through the filter 14, the corners of the trapezoidal wave for acceleration / deceleration are also smoothed. FIG. 2 shows the waveform of the frequency command before and after passing through the filter.

In FIG. 2, (a) shows the frequency command before passing through the filter and the waveform of the acceleration / deceleration pattern at that time.
(B) shows the frequency command after passing through the filter and the waveform of the acceleration / deceleration pattern at that time.

The time constant of the filter needs to be set to an appropriate value in advance. This setting is performed as follows.

First, when a motor constant calculation mode is selected from the outside by a switch or the like (not shown), a current automatically flows through the induction motor 6, and the motor constant is calculated based on a detection signal of the current detector 5 at that time. The calculation unit 16 calculates a motor constant. Using this calculation result, the filter time constant setting unit 17 calculates an appropriate filter time constant based on a balance between the time required for acceleration and deceleration of the elevator and the riding comfort, and stores the value.

By passing through the filter set in this way, it is possible to obtain a speed pattern in which the corners of trapezoidal wave acceleration / deceleration are smooth without increasing the time required for acceleration / deceleration more than necessary.

[0017]

According to the present invention, even if the speed command in the general-purpose inverter is used, the ride comfort can be improved without making the time required for acceleration / deceleration unnecessarily long. In addition, the time constant of the filter used for this purpose is set using the motor constant calculation function built in the general-purpose inverter in advance, so that the ride comfort of the elevator can be easily saved at each site without any trouble. Can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of the present invention.

FIG. 2 is a diagram illustrating a waveform of a frequency command and an acceleration / deceleration pattern before and after passing through a filter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Three-phase alternating current power supply 2 Converter 3 Smoothing capacitor 4 Inverter 5 Current detector 6 Induction motor 9 Basket 11 Inverter control device. 12 Speed command generator 13 Frequency command converter 14 Filter 15 Slip frequency calculator 16 Motor constant calculator 17 Filter time constant setting unit 18 Voltage / frequency calculator

Claims (1)

(57) [Claims] An AC elevator control device for controlling the speed of an elevator using a general-purpose inverter having a speed command generating means for outputting a speed pattern of trapezoidal wave acceleration / deceleration as a speed command, and a motor constant calculating means therein. At
And a filter time constant setting means for automatically setting a time constant of the filter using a calculation result of the motor constant calculation means while inserting a filter at a stage subsequent to the speed command generation means. AC elevator control device.