JPH0613394B2 - Test method for emergency stop device of elevator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing an elevator emergency stop device, and more particularly to a method for testing an elevator emergency stop device that employs an inverter device controlled by a vector control method. .

[Background of the Invention]

As is well known, inverter control is being adopted for elevators using an induction motor.

An elevator using this inverter control generates a primary current of a driving induction motor and a magnetic field flux of the motor in order to smoothly control the speed of the elevator, as described in JP-A-57-46695. The excitation current component and the torque current component that generates torque are divided into
A so-called vector control method is adopted in which the generated torque of the electric motor is instantaneously controlled. In this case, in order to simplify the control, the exciting current component that generates the field flux of the electric motor is controlled to be constant, and the torque current component is varied to generate the required electric motor torque. This motor torque is required to be about 250% of the rated torque when the rated load is started.
It will be about 0%. Therefore, as long as the inverter device (main circuit element etc.) is only in normal operation, it is sufficient if it can withstand the current of 250%.

By the way, as one of the safety devices in the elevator,
An emergency stop device is provided to hold the guide rail and stop the fall of the car when the free fall state is reached. This emergency stop device is
It is necessary to test or confirm the performance, and at this time, the electric motor needs a torque of 300 to 400% of the rated torque.

Therefore, in order to generate this torque, the torque current component is made to flow 300 to 400% of the rated time,
Since the main circuit element of the inverter device also needs to have a capacity capable of withstanding it, the device becomes expensive and large-scale.

[Object of the Invention]

An object of the present invention is to provide a test method for an elevator emergency stop device that can reduce the increase in capacity of an inverter device for test operation of the emergency stop device.

[Outline of Invention]

According to the vector control theory, the primary current of the induction motor is
It is divided into a torque current component It and an exciting current component Im which are orthogonal to each other. The exciting current component Im is normally controlled to be constant according to the exciting current command set at a point with a good power factor.

By the way, when Im ² + It ² ≦ (constant), the point where the torque T = Tm · It generated by the electric motor becomes maximum is Im = It.

Further, the emergency stop device is rarely tested, and is limited to short-time operation. Therefore, it is uneconomical to set the capacity of the inverter device large only for that purpose.

Therefore, in the present invention, an operating means for switching the exciting current command during the normal operation, that is, the preset constant first exciting current command to the second exciting current command having a larger value than this is provided, and the emergency stop device is provided. When the test operation is required, the inverter is switched so as to increase the primary current of the electric motor until the sheave and the rope idle while switching to the second excitation current command and operating the safety gear. by performing the vector control, to generate the required torque for the test operation of the emergency stop device in a torque current of about component I _t during normal operation (300 to 400% of the rated torque),
Therefore, it is intended to reduce the increase in capacity of the inverter device for the test operation of the emergency stop device.

Example of Invention

First, regarding the test operation of the emergency stop device, FIGS.
It will be described with reference to the drawings.

FIG. 2 is a schematic diagram of the configuration of the elevator. In the figure, 1 is a motor for driving an elevator, 2 is a rope, 3 is a counterweight, 4 is a sheave, 5 is a car, 6 is an emergency stop device (hereinafter abbreviated as "catch"), 7 is a guide shoe,
8 is a rail.

FIG. 3 shows the relationship between the catch and the rail as viewed from the car side. The chassis 6 has a rail 8 in the middle,
A wedge-shaped wedge 9 is built in the inner triangular cavity. In the normal state, it is stopped at the bottom by its own weight as shown by the solid line 9, but in an emergency, the wedge 9 is pulled up and bites into the cavity of the catch 6 as shown by the dotted line 9 '. As a result, the elevator is fixed to the rail and can be prevented from falling further.

The wedge 9 is pulled up by the speed governor 11 shown in FIG. Under normal conditions, basket 5 and governor rope 12
Are moving downward at the same speed.

If for some reason the descending speed overspeeds,
The governor 11 detects a critical speed and the governor rope 12
The rope 12 is fixed by the grasping mechanism. Then basket 5
The pulling rod 10 attached thereto is pulled up by the governor rope 12, whereby the wedge 9 of the catch 6 is pulled upward and the catch operates to prevent the elevator car 5 from falling.

Now, when the elevator is completed, as a verification of the elevator's safety, we let a wedge 9 bite into this catch 6 and an inspector of the government office will test whether the catch 6 can really prevent the car 5 from falling. In the test, in FIG. 2, the clutch 6 is first operated and the motor 1 is driven in the descending direction. Then the car 5 is stopped, so
The sheave 4 tries to feed only the rope from the counterweight 3 side to the car side, and finally the sheave 4 and the rope 2 start idling. If the force of the catch 6 is insufficient, the split cage with the rope 2 slipped downward without slipping, resulting in failure. This cache test
As mentioned above, a very large torque is required, which is about 3.0 to 4.0 times the normal running torque.

FIG. 1 shows an example of an elevator control device for carrying out the method for testing an emergency stop device according to the present invention.
In the figure, switching elements S _{1 to} S ₂₂ are reverse breakdown voltage self-extinguishing elements, such as gate turn-off thyristors (G
TO). Alternatively, the transistor may be replaced with a diode connected in series.

The elements S _{1 to} S _{6 form} a converter CON, and pulse width modulation control (PWM) is performed by the gate controller PC ₂ . Also element
S ₇ to S ₁₂ constitute an inverter (INV), it is PWM controlled by the gate controller PC _1.

Capacitors C _{1 to} C ₆ are filter capacitors that absorb harmonics on the input side and the output side, respectively. P is a general three-phase AC power supply, and IM is a drive motor for the elevator. R
E is an encoder for speed detection that checks the amount of rotation of the motor.

Next, the actual operation will be described.

When the speed command ▲ ω ^* _r ▼ is given and the actual rotation speed ω _r is fed back, the torque addition and deficiency and the slip amount are calculated by the speed control unit ASR from the deviation, and the torque current corresponding to the motor IM is calculated. ▲ I ^* _t ▼, slip frequency ω
_s is required.

On the other hand, since the exciting current ▲ I ^* _m ▼ of the motor IM is preset, the magnitude of the output current that the converter CON must generate from ▲ I ^* _m ▼ and ▲ I ^* _t ▼. Is required. This current I ₁ is compared with the actual current detected by the current detector CT, the required signal is calculated by the current controller ACR, and it is applied to the gate controller PC ₂ .

The gate control device PC ₂ also controls the elements S _{1 to} S ₆ by adding the signal from the isolation transformer PT. Further, the phase angle Θ ^{* of the} output current I ₁ is calculated from the ratio of ▲ I ^* _t ▼ and ▲ I ^* _m ▼ ^. Further, the frequency f ^{* of the} output current to be given to the motor IM is set from the slip frequency ω _s . The calculation part Θ _c is
From the formula of ω = 2πf ^* , the instantaneous value of the output AC i = I ₁ sin
Each variable corresponding to (ωt + Θ ^* ) is calculated and added to the gate controller PC ₁ .

This gate control device PC ₁ controls the currents of the three-phase motor IM via the elements S _{7 to} S ₁₂ .

In this way, the instantaneous value i = I ₁ sin (ωt + Θ ^* ) of the output current required for the elevator to operate stably is calculated, the gates of the converter CON and the inverter INV are controlled, and the predetermined operation is performed. Be done.

Further, the excitation current ▲ I ^* _m ▼ is selected appropriately from the power factor, efficiency and thermal conditions of the motor IM. Generally, this value is such that the power factor is 75-80% in rated operation,
That is chosen to _{^{▲ I * m ▼ / I 1}} = 0.6 around.

The operation of such a vector control system is shown in vector form as shown in FIG. 5. If the required exciting current I _m is controlled to be constant, the required torque of the elevator can be controlled in proportion to the torque current component I _t. It is a thing. This is the torque current I _t
This is because the following relation holds between the field flux φ generated by and the exciting current I _m .

Torque T _N = K ₂ · I _t · φ = K ₂ · K ₁ · I _t · I _m (1) where K ₁ is a coefficient indicating the degree of magnetic saturation of the iron core. K ₂
Indicates a constant of proportionality.

Well In this manner, when performing Kiyatsuchitesuto described above, it is necessary to increase the torque component I _t of FIG. 5 to I _t '. To simplify the explanation below, I _t = 0.8
Let I _1N and I _m = 0.6I _1N .

Now, I _t ′ = 3.0 · K ₂ · K ₁ · I _t · I _m = 3.0 · T _N (2) At the same time, the primary current I _1c becomes Therefore, if a larger torque is required, a larger current must be passed.

However, for example, in the transistor type inverter control, the maximum allowable current of the available transistor element is limited, so that the primary current cannot be freely increased as necessary.

Therefore, for example, generates a maximum torque while keeping the I _1c ≦ 2.5I _N, a maximum value problem as is well-known The product of I _'t and I' _m at giving the maximum torque becomes maximum. If there is no magnetic saturation in this calculation, the torque can be increased to 650/300 = 2.17 times as shown in column C of Table 1 even if the current value is the same. (Fig. 6) However, since the iron core of the motor IM actually has magnetic saturation, the magnetic flux φ generated for an exciting current exceeding a certain range.
Decreases as shown in FIG. K _{1 in} Eq. (1) decreases to less than ₁ as a proportional constant that gives the situation of this decrease.
The value varies depending on the basic design method. For example, when the exciting current is double, consider the case of K ₁ = 0.7. I _'m = 2 ×
0.6I _1N , the effective magnetic flux is φ ′ = 0.7 × 2 = 1.4, which is only 1.4 times, but from equation (3) the torque current I _t ′ is Or the torque T is T = K ₂ × 2.2 × 0.7 × 2 × 0.6 × I _1N ² / K ₂ × 1.0 × 0.8 × 0.6 ×
I _1N ² = 3.85 (6) That is, under normal vector control conditions, the rated value is 2.5.
The output torque can be increased by 28% by increasing the exciting current to twice the steady state and controlling the vector to the torque when the current is suppressed to twice or less (column B in Table 1). Table 1 shows the above results collectively.

On the other hand, in normal operation, when the iron core is used up to the saturation region, the excitation loss increases, causing overheating and lowering efficiency, which is uneconomical. Therefore, the controller is not designed as such.

However, the above-mentioned cache test is a short-time operation,
There is no problem in increasing the exciting current for such a short time.

Therefore, in this embodiment, an exciting current command I _m2 ^* is provided for the catch test operation, and during the catch test, the switching switch SW is used to switch to the exciting current command I _m2 ^* and the emergency stop device is operated to operate the motor IM. by performing the vector control of the inverter INV so as to increase the primary current I _1c to sheave 4 and the rope 2 is idling, the torque required for the test operation in the normal emergency stop device in a torque current of about component I _t during operation, That is, the rated torque of 30
A large torque of 0 to 400% is generated.

By the way, the method of generating the exciting current command I _m ^{2 *} differs depending on the method of vector operation processing, but in the case of configuring with fixed hardware, it may be switched by the switch SW or the like as described above, but with a microcomputer or the like. If you want to configure
It can also be realized by changing the table value of the internal memory or changing the coefficient in the calculation process. EFFECTS OF THE INVENTION According to the present invention, it is not necessary to increase the capacity of the inverter device for the test operation of the emergency stop device, which is required only for a short time, and the test operation of the emergency stop device can be economically performed. You can

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an example of an elevator control device for carrying out a method for testing an emergency stop device according to the present invention, FIG. 2 is a schematic diagram of the structure of an elevator, and FIGS. 3 (A) and 3 (B). Is a detailed view of the safety device, FIG. 4 is an explanatory diagram of the test operation of the safety device, FIGS. 5 and 6 are current vector diagrams, and FIG.
The figure is a saturation curve diagram of the iron core. P ...... three-phase power supply, CON ...... converter, INV ...... inverter, PC _1, PC ₂ ...... gate controller, RE ...... encoder, Θ _c ...... calculator, ACR ...... current controller, ASR
...... Speed controller, I _m1 ^* , I _m2 ^* …… Excitation current command, IM…
… Induction motor for driving elevators.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Takahashi, 1070 Ichige, Ito, Katsuta-shi, Ibaraki, Hitachi, Ltd., Mito Plant, Hitachi, Ltd. (72) Inventor Kiyoya Shima, 4026 Kuji Town, Hitachi City, Ibaraki Prefecture, Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takeki Ando, 4026 Kuji Town, Hitachi City, Ibaraki Hitachi Research Laboratory, Ltd. (72) ) Inventor Headquarters Mitsuyuki Head Office 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi Co., Ltd. (56) References JP-A-60-128885 (JP, A)

Claims (1)

[Claims] 1. An induction motor for driving an elevator, a sheave driven by this motor, an elevator car suspended by a rope with respect to the sheave, and an elevator car that responds to an overspeed of the car during normal operation. Emergency stop device for operating the electric car to prevent the car from falling, first exciting current command means for commanding a preset constant exciting current value of the electric motor during normal operation, and the first exciting current. An inverter control device for controlling an exciting current component of the electric motor by a command, and controlling a primary current of the electric motor according to a given torque command and the first exciting current command. Of the excitation current command value to a second excitation current command value larger than the first excitation current command value, and with the emergency stop device operating, The method of testing safety device of the elevator, characterized in that the primary current of the motor and to increase up to the sheave and the rope idles with switches the work unit to said second excitation current value.