JPS601268B2 - AC elevator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an AC elevator.

Using DC braking force as a control method for AC elevators,
There is one that applies a feedback control method.

That is, during startup, the primary voltage of the induction motor is controlled through a control device composed of a thyristor, etc., and during deceleration,
The primary winding of the induction motor is excited by direct current using a controlled rectifier also composed of a thyristor, and the motor is accelerated and decelerated while performing feedback control. This method currently provides good elevator characteristics, but on the other hand, the induction motor is controlled within a range of large slippage during both startup and deceleration, resulting in large rotor losses and a large waste of electric power. The disadvantage was that the temperature inside the machine room increased significantly. Also,
Another control method for induction motors is so-called variable voltage/variable frequency control (hereinafter referred to as VVVF control) that controls the frequency and voltage applied to the motor.

), but because the voltage and current applied to the motor contain harmonics, the motor generates large vibrations and torque ripples, especially at low speeds, making it unsuitable for elevators where riding comfort is important. was there. The present invention is intended to improve the above-mentioned drawbacks, and aims to provide an AC elevator control device that consumes less power and produces less vibration and noise.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is an elevator car, 2 is a counterweight, 3 is a main rope connecting car 1 and counterweight 2, 4 is a sheave around which main element 3 is wrapped, and 5 is connected to sheave 4 by a shaft. , a reducer that rotates this, 6 a rotor of a transmission motor for driving an elevator, 7 a brake wheel, which is braked by a shoe 9 pressed against the brake wheel 7 by a spring 8, and a coil 1
0, the shoe 9 separates from the brake wheel 7 and the brake is released, and the brake wheel 7, spring 8, shoe 9, and coil 10 constitute an electromagnetic brake.

The rotor 6 and the brake wheel 7 are on the same axis, and the reducer 5,
The car 1 is driven or controlled via the sheave 4. 11 is a stator winding of an induction motor for driving an elevator; 12 is a DC power supply section consisting of thyristors T, ~T6, and converts the three-phase AC power of dew reduction R, S, and T into DC; 13 is the above DC power supply The inverter section receives input from the inverter section and converts it into a variable frequency three-phase AC voltage, and is composed of thyristors T7-T,2, series diodes D,-D6, commutating capacitors C,-C6.

14 is a DC reactor. The torque serves to smooth the output current of the DC power supply section 12.

The power source 12, the inverter section 13, and the DC reactor 14 constitute a main circuit of a so-called current source inverter. 15
A speed reference generator 16 generates a speed reference signal 15a for the elevator car 1; 16 a speedometer generator connected to the rotor 6 and generates the speed signal 16a; 17 a speed control device for variable frequency control of the rotor 6. An amplifier generates a difference signal 17a between the reference signal 15a and the speed signal 16a.

Reference numeral 18 denotes a speed control amplifier for voltage control or DC braking of the rotor 6, which outputs a difference signal 18a between a reference signal 15a and a speed signal 16a, and a voltage/frequency converter 24 (hereinafter referred to as a V/F converter).

), 19 outputs the constant frequency signal 18a input to the
When the speed reference signal 15a reaches a predetermined value, the output 19a,
Detector 19b, 20', difference signal 17a, 18
Detector a! The distribution amplifier (CT) is a current transformer, and inputs from the power supplies R, S, and T. A current signal 22a is input to the current control amplifier 21 through the rectifier 22 by detecting the current.

The output 21a of the current control amplifier 21 is input to a phase control device 23, and its output controls the phase of the sirens T, -L to generate a variable DC voltage. 24 is the speed reference signal 1
5a into a corresponding frequency signal 24a, which is fed to a pulse splitter 255.

The pulse distributor 25 controls the thyristors T7 to T, , of the inverter section 133. Note that the other output 19b of the detector 19 is input to the V/F converter 24, and until the output 19b set at startup is generated, a constant value unrelated to the reference signal 15a is inputted to the V/F converter 24. After the output 19b is issued, a frequency signal corresponding to the reference signal 15a is generated. Further, during deceleration, a frequency signal corresponding to the reference signal 15a is generated until the output 19b is generated, and a zero frequency signal (DC signal) is generated after the output 19b is generated.
Next, the operation of this embodiment will be explained.

When the car 1 moves up, the coil 10 is first energized by a circuit (not shown) to separate the brake shoe 9 from the brake wheel 7, and then the speed reference generator 15 gradually increases the reference value 15a.

While the reference value 15a is small, the output 19a, 1 of the detector 19
Since 9b is not emitted, the distribution amplifier 20 outputs 18a.
is transmitted to the current amplifier 21, and the phase control device 23 controls the DC power supply section 12. On the other hand, the V/F converter 24 outputs a constant frequency signal 24a, which determines the output frequency of the pulse divider 25. The commutation operation is repeated at the frequency indicated by the output 24a, and a low frequency, low voltage three-phase AC input is applied to the primary winding 11.
The rotor 6 generates torque and the car 1 starts accelerating.
When the speed reference value 15a reaches a predetermined value, the detector 19 generates outputs 19a and 19b, and the distribution amplifier 20 transmits the difference signal 17a to the current controller 21 as an output 20a. Thereafter, as the speed reference signal 15a increases, the frequency signal 24a increases, and the DC power supply section 12 includes the speed control amplifier 17, the current transformer (CT), the rectifier 22, and the current controller 2.
1. Due to the action of the phase control device 23, the speed reference signal 15
The voltage and current necessary to accelerate car 1 are generated along line a, and car 1 is accelerated to the maximum speed indicated by speed reference signal 15a. When the car 1 reaches a predetermined distance before the floor to be stopped, a position detector (not shown) is activated and the speed reference signal 15a begins to gradually decrease. The frequency of the frequency signal 24a of the V/F converter 24 decreases, and the commutation point of the sirens T7 to T,2 starts to lag behind the counter electromotive force of the winding 11, so that the DC terminal of the inverter section 13 becomes negative, and the output voltage of the DC power supply section 12 also generates a voltage opposing this, and the kinetic energy of the car 1, weight 2, etc. is regenerated to the power supplies R, S, T, and the car 1 gradually decelerates.
Before the speed reference signal 15a decreases and the frequency signal 24a of the V/F converter 24 decreases, causing large torque ripples and vibrations in the rotor 6, the detector 19 operates and outputs 19a, 19b are generated. The output 24 of the V/F converter 24
Hold a at a zero frequency signal. In addition, the speed control amplifier 1
A difference signal 18a, which is the output of 8, is provided as an input 20a of a current control amplifier 20. Thereafter, the car 1 is decelerated and landed on the floor by the DC braking torque generated in the rotor 6 by the DC braking current generated by the DC power supply section 12. and coil 10
is deenergized, the shoe 9 is pressed against the brake wheel 7 by the force of the spring 8, and the car 1 is stopped. In addition, in this process, if the car 1 stops below the floor surface where it should land for some reason, the frequency signal generated by the V/F converter 24 is 24a is again reset to the above-mentioned constant frequency signal. Then, the inverter section 13 uses the DC braking current instead of the DC braking current.
Low-frequency three-phase AC power is applied to the winding amount 1, and the car 1 restarts and reaches the destination floor. Note that the output 18b is the difference signal 1
It is generated when 8a is positive. During deceleration, the output 24a of the V/F converter is used as a zero frequency (DC) signal at a speed lower than a predetermined speed, but this is used as a constant frequency signal with a different phase rotation direction for deceleration after the predetermined speed. , anti-phase braking may also be used.

In this case, the braking current increases slightly, but the thyristor T7
~Unlike when T,2 is DC braking, the inverter section 13
Thyristor T? Since the braking current is shared by sequentially commutating T and 2, the problem of only some thyristors being heated by energization is eliminated. As explained above, in this invention, most of the acceleration/deceleration is controlled by variable voltage/variable frequency control with low rotor loss, and DC braking is performed by generating DC in the low speed region, so power consumption is reduced. It is possible to configure an AC elevator control device with low vibration noise and good riding comfort.

[Brief explanation of drawings]

The figure is a block diagram showing an embodiment of an AC elevator control device according to the present invention. DESCRIPTION OF SYMBOLS 1... Car, 4... Sheave, 5... Speed reducer, 6... Rotor of induction motor for driving elevator, 11... Same left primary winding, 12... Variable DC power supply of isobverter device. Department,
13... Inverter section, T, ~T, 2... Thyristor, D, ~D6... Diode, C, ~C6... Commutation capacitor, 19... Detector, 24... V/F conversion vessel.

Claims (1)

[Claims] 1 An inverter device generates alternating current whose voltage is controlled and whose frequency is controlled in accordance with a frequency signal, which is supplied to an induction motor for driving a car, and whose speed is controlled according to a speed reference signal. , a detector for detecting that the speed reference signal has decreased to a predetermined value, and when the detector operates while the car is decelerating, the frequency signal is held at a zero frequency signal and the signal is output from the inverter device. A control device for an AC elevator, characterized in that it is equipped with a converter that generates a direct current.