JPS6317745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a re-flooring device for an AC elevator, and is particularly effective when an AC generator is used as a speed generator.

In an elevator, especially a high-lift elevator, when the car is stopped and the car floor is in line with the landing floor, when a passenger gets on or off the car, the rope suspending the car expands and contracts, causing the car floor to overlap the landing floor. There will be a difference in level. If the height difference becomes large, it can cause stumbling for passengers getting on and off the train, or impede the use of wheelchair users.Generally, in elevators where such problems may occur, the height difference exceeds a specified value. This is detected, and a re-alignment operation is automatically performed so that the car floor and the landing floor match.

By the way, this re-flooring operation is normally performed at an extremely low speed and under speed feedback control in order not to cause anxiety to elevator users and to prevent danger. Here, a typical example of a conventional floor re-aligning device for an AC elevator will be explained with reference to FIGS. 1 and 2.

Figure 1 is a block diagram showing the configuration of the re-flooring device. In the figure, IM is a three-phase induction motor for hoisting an elevator, which has a driving winding and a braking winding, and TG is a three-phase induction motor IM. A speed generator is directly connected and outputs a signal proportional to the speed of the elevator. R1a is a normally open contact of a relay (not shown) that is energized at the start of re-alignment operation and de-energized at the start of deceleration. PG is the speed of re-alignment. a speed command generator that issues a command signal;
ASR is a speed regulator that compares the speed command signal from the speed command generator PG and the actual elevator speed signal from the speed generator TG and amplifies the difference.
Further, ACR1 is a driving current regulator, AMP1 is a driving current amplifier consisting of a phase shifter and a thyristor circuit, and CT1 is a driving current detector, and these form a driving current adjustment loop as shown in the figure. ing. Similarly, ACR2, AMP2, and CT2 each form a braking current adjustment loop with a braking current regulator, current amplifier, and current detector.

FIG. 2 is a diagram showing the relationship between the speed command signal for re-flooring issued by the speed command generator PG and the actual speed of the elevator. C shown by a solid line in the figure is a speed command signal that rises when contact R1a closes at time _t1 , gradually decreases when contact R1a opens at deceleration start time _t2 , and reaches _zero at stop time t3 after a certain period of time. It returns and the brake is engaged. a and b are actual speed signals of the elevator during light load and heavy load, respectively, which will be described later.

In the above configuration, if a level difference exceeding a predetermined value occurs between the car floor and the landing floor due to a passenger getting on and off while the elevator is currently stopped, this is detected by an appropriate detection device (not shown), and contact R1a is closed. Re-floor leveling operation is started. Then, the deviation between the speed command signal and the actual speed signal of the elevator is compared and amplified by the speed regulator ASR, and the drive torque or braking torque is adjusted by the drive current regulation loop or the braking current regulation loop according to the output voltage, that is, the current command. Speed feedback control is performed over the entire range from time t ₁ to t ₃ while making adjustments, and when the elevator reaches the proper landing position at time t ₃ , the brake is engaged and the re-floor alignment operation is completed.

By the way, in general, the speed generator TG mentioned above is economical in AC elevators. For ease of maintenance, an alternating current generator is used and the speed signal is fed back through a rectifier circuit. in this case,
There is no problem at normal operating speeds, but when operating at extremely low speeds such as re-balancing, the ripples included in the output voltage of the alternator may increase, or the rectifier elements of the rectifier circuit described above may increase. Due to the nonlinear characteristics caused by the voltage drop due to For this reason, during re-flooring operation, as shown in Figure 2, the followability of the elevator's actual speed to the speed command is much worse than during normal operation, and as a result, at _t3 , which is the time when the brakes are applied, the elevator's actual speed is much worse. In the case of a heavy load, the brakes will be applied before the deceleration has reached a sufficient level, and in the case of a heavy load, the speed will once reach zero, and then the speed will reach a speed at which the DC braking torque and the load torque are balanced, that is, in the opposite direction. After the vehicle starts moving toward speed, the brakes will be applied. For this reason,
Conventional devices have the disadvantage of not only providing poor ride comfort but also giving passengers a sense of anxiety depending on the load condition.

In this case, a method to improve the above problem is to make the time from deceleration start time t ₂ to brake engagement time t ₃ variable depending on the load condition, or to change the speed command pattern during deceleration depending on the load. Although it is conceivable to change it, all of these require a means to detect the load state, which makes the device complicated and expensive, making it impractical.

The present invention has been made in view of the above points, and is an inexpensive device configuration that does not require a load detection device and provides a floor re-alignment device that does not cause discomfort or anxiety to passengers regardless of the load state of the elevator car. This is what we are trying to achieve.

The present invention will be explained in detail below based on the drawings. FIG. 3 is a block diagram showing one embodiment of the re-flooring apparatus according to the present invention. In the figure, R2a is a normally open contact of a relay (not shown) that is energized during deceleration during re-floor alignment operation and deenergized when stopped, R2b is also its normally closed contact, and LV is a speed regulator at the start of deceleration.
This is a command voltage changing device that changes the output of the ASR by a predetermined voltage, that is, the motor current command value by speed feedback control at the start of deceleration, by a certain value toward the braking side, and thereafter generates an output of that value. Note that the same parts as in FIG. 1 are indicated by the same reference numerals. In the above configuration, the re-leveling operation is started in the same way as in the case of FIG. The key is to use open-loop control. In other words, at the same time that contact R2b opens, contact R2a closes and during deceleration, the three-phase induction motor is controlled according to the output voltage of the command voltage changing device LV.The second feature is that this command voltage change Device
Regardless of the load condition, the output voltage of the speed regulator ASR at deceleration time t ₂ is changed by a predetermined voltage VE as shown in Figure 4, that is, the value is changed to the braking side by a constant value. That is to say. FIG. 4 shows the change in voltage at point A in FIG. 3 during deceleration, and FIG. 4a shows the case with a light load, and FIG. 4b shows the case with a heavy load.

Next, we will discuss the reason why the output voltage, that is, the current command, is changed to the braking side by a predetermined voltage VE during deceleration regardless of the load state. Generally, when the slip is constant, the torque T generated by an induction motor has a relationship of T∝I ² with respect to the primary current I of the motor, and this is illustrated for the drive side and the brake side as shown in FIG. 5. In Fig. 5, a1 is the point corresponding to the braking torque immediately before deceleration start time _t2 under light load, and b1
indicates the point equivalent to the drive torque immediately before deceleration start time t ₂ under heavy load, and corresponds to the current command based on the speed deviation at light load and heavy load at deceleration start time t ₂ in Figure 2. This is the point. Here, when the current command is changed to the braking side by a predetermined voltage VE at the deceleration start time _t2 as shown in Fig. 4 a and b, the braking torque changes from a1 to a2 at light load in Fig. 5, and the current command shifts from a1 to a2. Migrate by
Similarly, when the load is heavy, the driving torque shifts from b1 to b2. This is because, in a normal control system, the response of the current control system is quick, and therefore the primary current of the motor also shifts by a substantially constant amount by the amount of shift in the current command. As is clear from the figure, when the current command is changed to the braking side by a predetermined voltage, the torque change is larger in the case of a light load than in the case of a heavy load. Therefore, if the current command is changed to the braking side by a predetermined voltage regardless of the load condition during deceleration during re-leveling operation, the deceleration will be small for heavy loads and large for light loads, and the predetermined voltage VE By appropriately selecting the brake engagement time _t3 , the sixth
As shown in the figure, even if the brake is applied at time _t3 , which is a certain period of time after deceleration start time _t2 , the vehicle can be stopped smoothly without causing the above-mentioned problems. In FIG. 6, C' is the speed command, a' is the actual speed of the elevator when the load is light, and b' is the actual speed of the elevator when the load is heavy.

Next, a method for obtaining current commands as shown in FIGS. 4a and 4b will be explained with reference to FIGS. 7 and 8.

FIG. 7 is a diagram showing an example of a circuit of the command voltage changing device LV for obtaining the above-mentioned current command. In the figure, A1 to A3 are operational amplifiers, r1 to r9 are resistors, C1 and C2 are capacitors, VR1 is a variable resistor, P is a positive constant voltage power supply for control, and N is a negative constant voltage power supply. Also, R3a is R1
Like a, R4a is another normally open contact of a relay (not shown) that is energized at the start of re-floor alignment operation and deenergized at the start of deceleration; Another normally open contact, R4b, is also its normally closed contact. Components that are the same as those in FIG. 3 are designated by the same reference numerals. FIG. 8 is a diagram showing changes in the voltage waveforms at three points CP1 to CR in FIG. 7, and FIG. 8a shows the case when the load is light, and FIG. 8b shows the case when the load is heavy.

In the configuration shown in Fig. 7, if we are currently in re-levelling operation, the speed regulator ASR is
The motor is controlled via contact R2b by the output voltage or current command, while contact R3
Since a is closed, the output voltage of the speed regulator ASR is input to the command voltage changing device LV, and the voltage waveform at point CP1 after passing through the ripple filter consisting of resistor r1 and capacitor C1 is shown in Figure 8. It will be as shown. At this time, further resistance r2 from point CP1
As shown in Figure 8, the voltage waveform at CP2 passes through a bias inverter consisting of ~r5, variable resistor VR1, and operational amplifier A1, and an inverter consisting of resistors r6 to r8 and operational amplifier A2. Regardless, the voltage at point CP1 is lowered by a predetermined bias voltage VE determined by variable resistor VR1. Furthermore, since contact R4b is closed before deceleration starts, the output voltage of speed regulator ASR is smoothed through a first-order lag circuit consisting of resistor r9, capacitor C2, and operational amplifier A3, and the voltage waveform at point CP3 is as shown in FIG. As shown in the figure, the waveform almost matches the waveform at CP1. Next, when the deceleration start point _t2 is reached, contact R3a opens, but capacitor C1
If the discharge time constant determined by resistor r2 is set sufficiently large, the voltage waveform at point CP1 will maintain the state before deceleration start time _t2 , and therefore the voltage waveform at point CP2 will also maintain the state before deceleration start. Hold. On the other hand, at the start of deceleration _t2 , contact R4b opens and contact R
4a is closed, the voltage at the CP2 point is input in a stepwise manner to the first-order delay circuit with a resistor r9 or less. Therefore, the voltage waveform at the CP3 changes from the voltage just before the start of deceleration to the voltage just before the start of deceleration, as shown in FIG. predetermined voltage
With a first-order lag, the voltage approaches a nearly constant voltage that has decreased by VE. Then, at the stop time _t3 , which is a fixed time period after the deceleration start time _t2 , the contact R4a opens and the voltage at the CP3 point approaches zero with a first-order lag. Therefore, the voltage at point CP3, that is, the output voltage of the command voltage changing device LV, becomes as shown in FIG. 8, and the current command as shown in FIG. 4 can be obtained at point A in FIG. By passing the circuit through, it is possible to prevent deterioration of riding comfort due to sudden changes in the current command.

As described above, the present invention disconnects the speed feedback control at the time of deceleration during the re-flooring operation, and also uses the output that is changed to the braking side by a predetermined voltage from the speed regulator output voltage immediately before the start of deceleration, that is, the speed feedback control at the time of the start of deceleration. Since the control during deceleration is performed based on the output obtained by changing the motor current command value by a certain value to the braking side, using an alternator eliminates the variation in speed that occurs depending on the load condition during deceleration. enables smooth stopping even when
A floor re-alignment device that does not give passengers a sense of anxiety or discomfort can be provided with an inexpensive configuration without providing a load detection device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional floor re-alignment device, FIG. 2 is a diagram showing the relationship between the speed command signal and the actual speed of the elevator, and FIG. 3 is an implementation of the floor re-alignment device according to the present invention. FIG. 4, a block diagram showing an example, is a diagram showing the change in the output voltage at point A in FIG. Figure 5 is a diagram showing the relationship between torque and primary current of a three-phase induction motor, Figure 6
The figure shows the relationship between the speed command signal and the actual speed of the elevator according to the present invention, Figure 7 shows an example of a circuit of the command voltage changing device LV, and Figure 8 shows the CP of Figure 7.
In the diagram showing changes in voltage waveforms at points 1 to CP3, a shows the time of light load and b shows the time of heavy load. PG...speed command generator, ASR...speed regulator,
ACR1, ACR2...Current regulator, AMP1, AMP
2...Current amplifier, CT1, CT2...Current detector,
IM...three-phase induction motor, TG...speed generator, LV...
Command voltage changing device, R1a, R2a, R3a, R
4a... Normally open contact, R2b, R4b... Normally closed contact.

Claims (1)

[Scope of Claims] 1. An alternating current generator is used as a speed generator to detect the actual speed of the elevator, and when the level difference between the car floor and the landing floor exceeds a predetermined value after landing, the car is restarted. Speed feedback that compares and amplifies the deviation between the speed command signal and the actual speed signal of the elevator using a speed controller, and controls either the drive current adjustment loop or the braking current adjustment loop according to the compared and amplified motor current command value. In a re-flooring device for an AC elevator that performs re-flooring operation under control, the motor current command value at the start of deceleration during re-flooring operation is changed by a certain value to the braking side, and thereafter the command voltage is changed to output that value. and a circuit for switching from the speed regulator to the command voltage changing device during deceleration of the re-flooring operation, and performs open loop control according to the output of the command voltage changing device during the deceleration of the re-flooring operation. A re-floor alignment device for an AC elevator, characterized in that: