JPH0559033B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a control device that detects the load of elevator passengers and performs balance control in a device that controls an elevator by controlling the primary voltage of a three-phase squirrel cage motor. .

[Technical Background of the Invention] Conventionally, inexpensive and sturdy three-phase squirrel cage motors have been used to control elevators in medium-sized buildings such as apartments and condominiums. On the other hand, as a control device, a primary voltage control method has been adopted in which the primary voltage applied to the three-phase squirrel cage motor is varied by controlling the phase of a thyristor. This primary voltage control method has a simple system and is easy to implement.
Since it is inexpensive, it has been widely used until now.

Further, the operation mode of the elevator is divided into two, a power running mode and a regeneration mode, depending on the number of passengers, the driving direction, and the acceleration/deceleration state.

By the way, there are three ways to control a three-phase squirrel cage motor: ○A regenerative braking ○B reverse phase braking ○C DC dynamic braking.

○The regenerative braking in A is rated when the elevator is operating in the load torque direction such as full load descent, and is performed during steady running, and the speed at this time is the negative speed of the three-phase squirrel cage motor that is balanced with the load torque. Controlled by the torque characteristics of the slip.

At this time, the regenerated energy of the elevator is regenerated into the power source. In addition, reverse-phase braking (○A) and DC dynamic braking (○C) generate braking torque in the motor by passing a reverse-phase current or direct current to the motor when the elevator is decelerating, and control this braking force. This is used to control the deceleration of the elevator.

Generally speaking, regenerative braking and other types of reverse-phase braking and DC dynamic braking are used properly.In order to reduce the temperature rise of the motor as much as possible, braking during steady running in the load torque direction is regenerative braking, and the regenerative current is transferred to the power supply side. Regeneration prevents the temperature of the motor from rising. Furthermore, when it is necessary to control the braking force, such as when decelerating an elevator, reverse-phase braking or DC power generation braking is applied to control the braking force applied to the electric motor.

By the way, the elevator is not in balance,
For example, under full load, there will be a drop in the case of an upward selection and a pop-up in the case of a downward selection, accompanied by a starting shock. Similarly, when landing is stopped, the direction in which the elevator is pulled by the load,
On the other hand, there is a direction in which braking is applied, which causes a stop shock when landing.

On the other hand, at the time of landing on the floor, the landing level differs depending on the influence of the load, and in the case of full load, the landing level deviates in a negative direction from the level.

To deal with such problems when starting and stopping, and the effects on the level, high-speed, high-end models that use DC motors have traditionally detected the state of the elevator car, and constantly flowed current commensurate with the load. I have been trying to control it by bringing it into a state of balance.

A block diagram of an example in which this balance control is used for primary voltage control in a three-phase squirrel cage motor is shown in Figure 1.
As shown in the figure.

In FIG. 1, 1 is a speed command generation circuit, and 2 is a speed control operational amplifier which receives the difference between the speed command signal 1a and the speed detection signal 15a as an input and outputs a current reference signal 2a. 3 is a differential amplifier that adds the current reference signal 2a and the load detection signal 16a of the load detector 16, and this output 3a becomes a current command value, which is the sum of the load detection signal 16a and the current reference signal 2a. . 4 is a current control operational amplifier which inputs this current command value 3a and current feedback amount 8a and outputs a control amount to the thyristor. Further, 5 is a phase control circuit, which is the output 4 of the current control operational amplifier 4.
A is inputted, and the output 6a of a polarity discrimination circuit 6 for discriminating the polarity of the current command value 3a is inputted to determine the selection of the thyristor and the firing angle. Reference numeral 6 denotes a polarity discrimination circuit that discriminates the polarity of the current command value 3a and switches the selection of the thyristor and the polarity of the current feedback amount 8a. Reference numeral 7 denotes a primary voltage control thyristor stack connected in antiparallel, which can be switched between normal phase and negative phase. 8 is a current detector, 9 is a three-phase AC power source, 10 is a three-phase squirrel cage electric motor, 11 is a main rope connected to the electric motor 10 through a reducer, 12 is an elevator car, and 13 is a car and main rope. It is a counterweight connected through. 14 is a pulse generator that detects the speed of the elevator; 15 is an F/V conversion circuit that converts the output of the pulse generator into frequency/voltage; and 16 is a load detector provided under the floor of the elevator car. The load detection signal 16a detected from under the floor of the elevator car is the load when the elevator is stopped, which is held in memory, and even when the current reference signal 2a is zero, a constant balanced current command value is output, and the current command value is adjusted to this value. An appropriate balanced current is applied to the motor 10.

Figure 2 shows the case without load compensation.
FIG. 2a, which shows the current command value and operation mode, shows the case where no load compensation is performed, and the vehicle enters steady running in the power running state and shifts to the regeneration mode. During this time, only the phase control signal changes without switching the polarity of the current reference signal 2a.

On the other hand, FIG. 2b is a characteristic diagram when load compensation is performed. This state indicates, for example, a full load drop state, and before the pattern rises, a balanced current flows in the reverse phase mode to perform static control, and then control starts, the current reference signal 2a increases, and the current reference signal 2a The polarity of the current command value 3a added to the load detection signal 16a is switched, and the mode shifts to power running mode.
By adding a, the zero level is shifted downward.
By the way, when entering the acceleration termination mode, a jerk appears in the pattern and the current reference signal 2a decreases. Since the load detection signal 16a is outputting a constant value, the polarity of the current command value 3a is switched again and the reverse phase mode is entered. When entering the reverse phase mode, the speed of the elevator will exceed the speed command signal 1a.

[Problems with the Background Art] This speed command signal 1a is set in advance to be higher than the rated speed, and the regeneration mode is set during load torque operation such as when the full load is lowered, so the elevator speed at this time is lower than the load Although it varies depending on the torque value, it will result in overspeed compared to regenerative braking operation, and in the worst case, an emergency stop will be required.

In this way, when performing rated driving in the torque direction under primary voltage control and performing regenerative braking instead of reverse phase braking, if stationary control using load compensation is performed in the entire driving range, the transition from normal powering mode to regenerative mode When the engine moves to , it does not go into regeneration mode, but instead goes into reverse phase mode, which is a problem.

[Object of the Invention] The present invention provides an elevator control device that overcomes the drawbacks of conventional devices, eliminates the influence of load compensation control, performs mode conversion normally, and performs static control at start and stop times. Its purpose is to provide.

[Summary of the Invention] The present invention detects the load of the elevator car in order to reduce start and stop vibrations in a method of driving an elevator by controlling the primary voltage of a three-phase squirrel cage motor, and adjusts the load to speed. When adding to the control signal to compensate for the load, if the load detection signal is input as is, regenerative braking will not be obtained during load-direction operation such as no-load up or full-load down operation of the car, resulting in plugging. In order to eliminate the influence of the operating load in the torque direction, enable regenerative braking, reduce power consumption due to plugging, utilize load compensation in the low speed range, and perform complete balance control in the zero speed state. The elevator speed detection signal is subtracted from the elevator load detection signal, and when the speed is zero, balance control is performed using the same load detection signal, and as the speed increases, load compensation is reduced, and from around the rated speed, the elevator speed command is set. This is an elevator control device that performs control using a value and an elevator speed detection signal.

[Embodiment of the Invention] A block diagram showing the configuration of an embodiment of the present invention is shown in FIG.

The same reference numerals represent the same or corresponding parts in all drawings.

In FIG. 3, 17 is a load signal control circuit according to the present invention, in which an output 16a of a load detector disposed under the elevator car floor and a speed detection signal 15 are provided.
Enter a.

17a is an absolute value amplifier, 17b is a polarity inversion amplifier, and 17c and 17d are respectively the load detection signal 16a and the absolute value amplified speed detection signal 1.
5a is a differential amplifier with a limiter, and output polarities of these 17c and 17d differ depending on the polarity direction of the limiter. The signal 17e is the output of the load signal control circuit 17, and is matched with the current reference signal 2a to obtain the current command value 3a.

FIG. 4 is a block diagram showing the configuration of one embodiment of this load signal control circuit.

The speed detection signal 15a is input to the absolute value amplifier 17a.

The absolute value amplifier 17a outputs a positive signal output regardless of the polarity of the speed detection signal 15a.

171 to 178 are resistors, 179 is an adder, 18
a, 18b, 18c are inverting amplifiers, 19a, 19
b is a diode.

The absolute value output of the absolute value amplifier 17a is input to the polarity inverting amplifier 17b, the polarity of which is inverted, and the absolute value output is input as a negative signal to the differential amplifier 17d.

Further, the output of the absolute value amplifier 17a is inputted as a positive signal to the differential amplifier 17c.

Now, consider a case where the polarity of the load detection signal 16a is positive.

In the differential amplifier 17c, the resistors 173, 17
Since all the calculations in 5 are positive signals, the inverting amplifier 18b is bypassed via the diode 19a, and its output is not amplified, so it becomes a substantially zero output compared to the amplified output.

In the differential amplifier 17d, the resistor 176 has a positive signal and the resistor 178 has a negative signal, so the differential voltage is input to the inverting amplifier 18c, where it is amplified and outputs the load control signal 17e. Diode 1
9b prevents the input signal from being bypassed by the inverting amplifier 18c.

When the polarity of the load detection signal 16a is negative (depending on the elevator car's elevation and the amount of passengers), the output of the differential amplifier 17d is approximately zero, and the amplified output of the differential amplifier 17c is the load control signal 17e. Output.

When the car is stopped and the balance control is performed, the speed detection signal 15a is zero and only the load detection signal 16a is amplified to become the load control signal 17e. In this case, when the polarity of the load detection signal 16a is positive, the differential amplifier 17d operates, and when it is negative, the differential amplifier 17c operates.
works.

Figure 5 shows load detection signal 1 for balance load.
The load detection signal 16a with respect to the load amount when 6a is set to zero is shown.

Now, when the elevator is stopped under full load, the load detection signal 16a outputs a positive value of V ₀ (V ₀ ≧0). Since the elevator is in a stopped state, the speed detection signal 15a is zero, and only the load detection signal 16a is input to the load signal control circuit 17. At this time, since both the absolute value signal and its inverted signal of the speed detection signal 15a in FIG.
7d. Since the output of the load detection signal 16a is positive, the output of the differential amplifier 17c becomes zero due to the limiter diode 19a, and only the negative output signal of the differential amplifier 17d is output. This signal becomes the load control signal 17e,
When the elevator is stopped, the current reference signal 2a
is zero, this load control signal 17e becomes the current command value 3a, and a current commensurate with the unbalanced torque due to the full load is passed through the motor 10 to perform stationary control.

Next, when braking starts and full load descending operation begins,
The speed detection signal 15a is input to the load signal control circuit 17 as a positive detection signal. Therefore 17c
Since the same positive signal as the load detection signal 16a is input to the differential amplifier, the output remains zero.
On the other hand, the differential amplifier 17d outputs the load detection signal 1.
A negative speed detection signal 15a with the opposite polarity to 6a is input, and the load detection signal 16a is converted into the speed detection signal 1.
Perform the subtraction operation according to 5a.

This state is shown in FIG. 6a. Load control signal 1
The speed value at which 7e becomes zero is determined by the output of the absolute value amplifier 17a, and if the gain of the amplifier circuit is increased, the load control signal 17e becomes zero at low speeds. By setting the load control signal 17e to zero before the end of acceleration in this way, the transition from the power running mode to the regeneration mode can be performed using only the current reference signal 2a, so the speed command value By setting the speed above the rated speed, it is possible to shift to regeneration mode.

The current command value at this time is shown in FIG.

On the other hand, at the time of starting, static control is performed using the load control signal 17e that completely matches the load torque, so there is no starting shock.

Further, when the deceleration mode is entered and the speed exceeds the speed command value and anti-phase braking is applied and the speed of the elevator is reduced, the load detection signal 16a is again output to the absolute value amplifier 17 set by the speed detection signal 15a.
a, the load detection signal 16a is output.

This signal is represented in FIG. 6b.

When the elevator decelerates and reaches completely zero speed, the current reference signal 2a is zero and the load control signal 17e is not subtracted by the speed, but becomes a control signal equivalent to the load, and stationary control is performed. Let's do it.

Therefore, the brake can be applied when the elevator is completely stopped, and floor landing control can be performed without depending on the brake as in the past.
The same applies to the case of no-load operation, the polarity of the load detection signal 16a is different, and the differential amplifier 17c which is opposite to that in the case of full load outputs, and the opposite differential amplifier 17d has a zero output.

In this way, continuous stationary control is possible under all load conditions, and it is possible to avoid situations where the control mode changes from power running to reverse phase mode due to the influence of the load control signal, such as during torque direction operation. .

[Effects of the Invention] Thus, according to the present invention, it is possible to shift from the power running mode to the regeneration mode without being affected by the load in the torque direction operation (positive polarity of the load detection signal).

In addition, since anti-phase braking does not occur during steady driving, sudden stops due to heat generation and overspeeding do not occur.

Furthermore, since the load detection signal is controlled by the speed detection signal, complete standstill control is possible at start and stop times.

Furthermore, since the load detection signal is continuously decreased depending on the speed, no sudden changes in torque occur.

Therefore, the present invention is of great benefit to this field.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the primary voltage control system of an elevator equipped with conventional load compensation control.
Fig. 2a is a diagram showing the current command value and control mode when conventional load compensation is not performed, Fig. 2b is a diagram showing the current command value and control mode when conventional load compensation is performed, and Fig. 3 is a diagram showing the current command value and control mode when conventional load compensation is performed. 4 is a detailed diagram of the load signal control circuit, FIG. 5 is a diagram of the load detection signal, and FIGS. 6 a and b show the acceleration and FIG. 7 is an output waveform diagram of the load signal control circuit during deceleration, and is a diagram showing the current command value and control mode when load compensation is performed according to the present invention. 1...Speed command generation circuit, 2...Speed control operational amplifier, 3, 17c, 17d...Differential amplifier,
4... Operational amplifier for current control, 5... Phase control circuit, 6... Polarity discrimination circuit, 7... Thyristor stack, 8... Current detector, 9... Three-phase AC power supply,
10...Three-phase squirrel cage electric motor, 11...Main rope, 12
... Elevator car, 13 ... Counterweight, 14 ... Motor speed detector (pulse generator), 15 ... F/V conversion circuit, 16 ... Load detector, 17 ... Load signal control circuit, 17a …
...Absolute value amplifier, 17b, 18a-18c...Polarity inversion amplifier, 17e...Load control signal, 19
a, 19b...Diode, 171-178...
Resistor, 179...adder.

Claims (1)

[Claims] 1. A speed command generation circuit that sets a positive or negative speed of the elevator; a motor speed detector that detects the positive or negative speed of the elevator, inverts its polarity, and outputs it; and a speed command. A speed control operational amplifier that operationally amplifies the difference between the speed command signal that is the output of the generator circuit and the speed feedback signal detected from the elevator and outputs the inverted polarity; a load detector that outputs a negative load detection signal; a first differential amplifier that amplifies the algebraic sum of the current reference signal that is the output of the speed control operational amplifier and the elevator car load control signal; a current control operational amplifier that operationally amplifies the difference between the current command value that is the output of the first differential amplifier and the current flowing through the elevator motor; an input from the current control operational amplifier; and the first differential amplifier. A phase control circuit that determines the polarity of the output of a thyristor to control the conduction phase of a thyristor that drives an elevator motor, a thyristor stack that drives an elevator motor, and an elevator motor that raises and lowers an elevator car. At the same time, an absolute value amplifier circuit that introduces the elevator speed detection signal and outputs a positive output, and an absolute value amplifier circuit that inputs the output of the absolute value amplifier circuit and the load detection signal of the elevator car, and when the load detection signal is positive, When the output is zero and the load detection signal is negative, the second difference calculates the algebraic sum of the load detection signal and the output of the absolute value amplifier circuit, and outputs a positive output with a certain output limit value. A dynamic amplifier, a polarity inverting amplifier that inverts the polarity of the positive output of the absolute value amplifier circuit and outputs a negative output, and inputs the negative output of the polarity inverting amplifier and the load detection signal, and when the load detection signal is negative, When the output is zero and the load detection signal is positive, a third controller calculates the algebraic sum of the negative output of the polarity inverting amplifier and the load detection signal, and outputs a positive output with the constant output limit value. a differential amplifier, the output terminals of the second and third differential amplifiers are commonly connected to form a common connection terminal, and the output from the common connection terminal is applied to the first differential amplifier. An elevator control device characterized by comprising a circuit.