JP2001354366A - Control device for elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an elevator for preventing to the at most a passenger from being confined there even when the elevator stops between floors in failure of an electric motor control system. SOLUTION: This control device of the elevator employs a permanent magnet shaped synchronous motor as a motor 1 for driving a hoisting machine and can supply alternating current power with variable voltage and variable frequency. The control device has a bus voltage command circuit 22 that releases a brake 6 to move the elevator toward a light load part and generates a reference voltage when the elevator stops between floors in failure of the electric motor control system, controls direct current bus voltage with a discharge circuit connected to the direct current side of an inverter 11 by a bus voltage control circuit 16, and operates a car 4 of the elevator to the nearest floor. Thus, the passenger can be rescued safely to reduce confining rate of the passenger in the failure of the electric motor control system. A rescue operation can be performed inexpensively without adding a dedicated apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elevator control apparatus for controlling an electric motor for driving a hoist by supplying AC power having a variable voltage and a variable frequency converted by an inverter to an electric motor. The present invention relates to a control device for an electric braking force of an electric motor.

[0002]

2. Description of the Related Art FIG. 6 shows an apparatus for controlling an electric motor by supplying AC power having a variable voltage and a variable frequency converted by an inverter. FIG. 6 shows, for example,
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram showing an elevator control device similar to that shown in Japanese Patent No. 9164 and the like. In FIG. 6, 1
Is an electric motor, 2 is a sheave of a hoist driven by the electric motor 1, 3 is a main rope wound around the sheave 2 of the hoist, 4 is an elevator car attached to one end of the main rope 3, 5 is a counterweight attached to the other end of the main rope 3, 6 is a brake for generating a mechanical braking force, and releases the brake 6,
By driving the electric motor 1, the elevator car 4
Up and down.

Further, 7 is a three-phase AC power supply, 8 is a contact of an electromagnetic contactor which is closed when the elevator is started, 9 is a converter for converting AC to DC, 10 is a capacitor between DC buses for smoothing DC, 11 Is a voltage-source inverter configured by connecting a switching element 11a and a diode 11b in parallel and converting a DC bus voltage to an AC voltage having a variable voltage and a variable frequency. 12 is a feedback current detection for detecting an output current of the inverter 11 as a feedback current. , 13 is the inverter 11
Is an inverter control circuit for controlling the switching element of FIG.

Further, 14 is a resistor for consuming regenerative electric power, 15 is a discharging circuit together with the resistor 14, an energizing element for flowing current through the resistor 14, and 16 is a voltage of the DC bus capacitor 10. When the specified value is exceeded,
This is a bus voltage control circuit that issues a conduction command to the energizing element 15. Reference numeral 17 denotes a motor provided on the rotating shaft of the electric motor 1.
A speed detector for generating an elevator speed command; 19, a speed control circuit for generating a current command based on the feedback speed and the speed command; and 20, a DC bus current. Current detector for detecting
Is an overcurrent detection circuit for monitoring the signal of the current detector 20.

Next, the operation of the conventional elevator control device will be described. When a start command is input to the elevator, the contact 8 of the electromagnetic contactor is closed, and AC power flows from the three-phase power supply 7 to the converter 9. Converter 9 converts AC power to DC power, charges capacitor 10 and supplies power to inverter 11. When the brake 6 is released, a speed command is generated from the speed command generation circuit 18, and the speed control circuit 19 sends a current command to the inverter control circuit 13 based on the speed command and the feedback speed. The inverter control circuit 13 controls the inverter 11 based on the current command and the feedback current, generates an AC voltage having a variable voltage and a variable frequency, rotates the electric motor 1, and engages the sheave 2 of the hoist and the The elevator car 4 is moved up and down via the main cable 3.

[0006] When the motor 1 enters a regenerative operation, for example, when the inside of the car performs an ascending operation with no load, the regenerative electric power circulates through the diode 11b of the inverter, and the voltage of the capacitor 10 increases. The bus voltage control circuit 16 detects that this voltage has become equal to or higher than a predetermined value.
, A regenerative power is consumed by the resistor 14, and the voltage of the capacitor 10, that is, the DC bus voltage is reduced.
By repeating this, regenerative electric power is consumed, and the voltage between the DC buses is maintained at a predetermined value or less.

Further, the overcurrent detection circuit 21 constantly monitors the DC current flowing into the inverter 11 by the DC bus current detector 20, and when the current value exceeds a predetermined value due to a fault such as a load short circuit. When the overcurrent detection circuit 21 recognizes the abnormality, the elevator is suddenly stopped instantaneously by shutting off the switching element 11a of the inverter or opening the contact 8.

[0008] The AC power supplied to the motor due to a fault in the motor control system, such as a fault in the feedback current detector 12, the speed detector 17, a fault in the switching element 11a of the inverter, or a fault in turning off the contact 8 in the electromagnetic contactor. If the control cannot be performed, the restart of the elevator is prevented due to a serious failure.

[0009]

Since the conventional elevator control device is constructed as described above, if the elevator car stops between floors due to a failure of the motor control system, the elevator is restarted. It was no longer possible and passengers were trapped in the car. In order to prevent confinement, it is conceivable to prepare two systems of detectors and drive circuits as a double system, but there is a problem that the control device becomes expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. An elevator control capable of safely guiding passengers trapped between floors to the nearest floor and rescuing the passengers. It is intended to provide a device. It is another object of the present invention to configure the elevator control device at a low cost without providing a dedicated detector or a driving device.

[0011]

An elevator control apparatus according to the present invention includes a three-phase AC power supply, a converter for converting AC from the three-phase AC power supply to DC, a three-phase AC power supply, and the converter. And a capacitor connected to the DC bus side of the converter for smoothing DC, and a parallel connection of a switching element and a diode, and converts the DC bus voltage of the converter into an AC voltage. An inverter, an electric motor for driving the hoist based on the output from the inverter, a brake for generating a mechanical braking force on the sheave of the hoist driven by the electric motor, a resistor, and a current flowing through the resistor. And a discharging circuit configured to connect a current-carrying element for controlling the capacitor in series and connected in parallel to the capacitor to discharge a charging voltage of the capacitor. Current detecting means for detecting a current flowing between an inverter and the motor, an inverter control circuit for controlling a switching element of the inverter based on a current detected by the current detecting means, and a bus voltage charged to the capacitor. A bus voltage control circuit that controls the current-carrying element based on a permanent magnet synchronous motor as the electric motor, and generates a bus voltage reference voltage to the bus voltage control circuit. Further comprising a bus voltage command circuit for outputting, by the bus voltage control circuit, when the bus voltage exceeds a reference voltage, so as to conduct the conducting element,
When the elevator stops between floors and the motor control system fails and cannot be started, the brake is released while the electromagnetic contactor and the switching element of the inverter are in a cutoff state, and the bus voltage is reduced to a reference voltage or less. It is characterized by controlling.

Further, the inverter is a voltage type inverter.

Further, the bus voltage command circuit determines the reference voltage based on an unbalanced load of a car and a counterweight and a rescue operation speed.

Further, the bus voltage command circuit is characterized in that the reference voltage is determined based on a difference between a rotation speed of the motor and a speed command.

Further, the present invention is characterized in that the rotation speed of the electric motor is detected by the pulsation of the current of the DC bus.

Further, the present invention is characterized in that the rotation speed of the electric motor is detected by pulsation of the voltage of the DC bus.

[0017]

FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of an elevator control device according to the first embodiment, particularly shows a configuration during a rescue operation, and shows a part of the same parts as those of the conventional example shown in FIG.

In FIG. 1, the same reference numerals as those in the conventional example shown in FIG. 6 denote the same parts, and a description thereof will be omitted. However, the motor 1 employs a permanent magnet synchronous motor. As a new code, reference numeral 22 denotes a bus voltage command circuit that generates a reference voltage of the DC bus voltage, 30 denotes a weighing device that measures the load in the car, and the bus voltage command circuit 22 outputs a value detected by the weighing device 30. The reference voltage is determined based on the unbalanced load of the car 4 and the counterweight 5 and the rescue operation speed, and is output to the bus voltage control circuit 16. Based on this, the bus voltage control circuit 16 When the voltage, that is, the bus voltage stored in the capacitor 10 exceeds the reference voltage,
When the elevator is stopped between floors so that the motor control system fails and cannot be started, the electromagnetic contactor 8 and the switching element 11a of the inverter 11 are kept in the cut-off state. And the bus voltage is controlled to be equal to or lower than the reference voltage.

Next, the operation of the elevator control device according to the present embodiment during rescue operation will be described. Note that the elevator control device according to the present embodiment has the same configuration as the conventional example shown in FIG. 6 during normal operation, and operates in the same manner.

When the elevator stops between floors and cannot be restarted due to a failure in the motor control system, the control device operates as follows. First, the brake 6 is released with the contact 8 of the electromagnetic contactor kept open. The inverter control circuit 13 controls the switching element 11 of the inverter.
a is kept electrically disconnected.

Normally, there is some load imbalance between the car 4 and the counterweight 5, and when the brake is released, the sheave 2 of the hoist rotates so that it is pulled to the heavier one. The engaged electric motor 1 rotates. When the motor 1 is a permanent magnet synchronous motor, the motor 1 acts as a generator due to rotation by external force, and the generated power is
Flows into Switching element 11a of inverter 11
Is electrically cut off, the generated power from the motor 1 flows into the DC bus through the diode 11b of the inverter 11. This current causes the electric motor 1 to generate a braking force.

However, since the converter 9 does not regenerate power to the power supply side, the capacitor 10 is charged and the bus voltage gradually rises, and when the induced voltage of the motor 1 and the bus voltage are balanced, the motor 1 Can no longer flow from the DC bus to the DC bus, and the braking force of the electric motor 1 becomes zero. As a result, the speed of the car 4 is further increased.

Therefore, in the control device according to the present invention, in order to suppress the speed of the electric motor 1 below the rescue operation speed commanded from the speed command generation circuit 18, the control device is preset according to the car internal load measured by the weighing device 30. The bus voltage command circuit 22 commands a reference voltage of the bus voltage based on the obtained unbalanced load. When the bus voltage, that is, the storage voltage of the capacitor 10 exceeds the reference voltage, the bus voltage control circuit 16 causes the energizing element 16 to conduct so that the DC bus, that is, the capacitor 1
The power stored in 0 is consumed by the resistor 14, and the voltage of the DC bus is reduced. By repeating this, the bus voltage is maintained at or below the reference voltage, and the braking force of the motor is continuously ensured. The resistor 14 acts equivalently as a braking resistor of the electric motor 1. In this way, by keeping the bus voltage below the reference voltage, it is possible to slow the car 4 to the nearest floor while maintaining the speed of the elevator car 4 at a safe speed.

The reason why the speed of the car 4 can be controlled by controlling the bus voltage is as follows. Considering that the induced voltage is proportional to the speed, the current is proportional to the voltage difference between the induced voltage and the bus voltage, and the braking torque is proportional to the current in the permanent magnet synchronous motor 1,
The relationship between the motor speed and the braking torque is as shown in FIG.
In addition, considering a steady speed, the braking torque can be regarded as an unbalanced load. Therefore, if the bus voltage is controlled according to the unbalanced load at that time, the speed of the electric motor 1 can be suppressed to a predetermined value or less, and the speed of the car 4 can be controlled.

By doing so, the first embodiment
According to the elevator control device according to the above, during the rescue operation, the speed detector 17, the feedback current detector 12, the switching element 11 a of the inverter 11, and the electromagnetic contactor 8, which are considered to be faulty, can be safely used. The car 4 can be driven to the nearest floor to rescue passengers. In the above-described control, the bus voltage and the motor speed shown in FIG.
It is necessary to grasp the relationship between the braking torques and accurately detect the unbalanced load during the rescue operation.

Embodiment 2 FIG. On the other hand, a configuration according to the second embodiment shown in FIG. 3 can be considered as a configuration not using the relational data of the bus voltage, the motor speed, and the braking torque shown in FIG. FIG. 3 shows a configuration of an elevator control apparatus according to Embodiment 2 of the present invention, and particularly shows a configuration at the time of rescue operation, similar to Embodiment 1 shown in FIG. 6, parts similar to those in the conventional example shown in FIG.

In FIG. 3, the same reference numerals as those in the first embodiment and the conventional example shown in FIGS. 1 and 6 denote the same parts, and a description thereof will be omitted. As a new code, reference numeral 23 denotes a bus voltage command circuit that creates a bus voltage reference voltage based on a deviation between the speed command from the speed command generation circuit 18 and the feedback speed from the speed detector 17 during rescue operation.

At the time of braking, as shown in FIG. 2, since there is a proportional relationship between the motor speed and the bus voltage, if the reference voltage is commanded by the bus voltage command circuit 23 based on the deviation of the speed, the feedback speed is reduced. It can follow the command speed. Accordingly, the car can be reliably driven at the command speed based on the detected value of the motor speed, so that passengers can be more safely rescued.

Embodiment 3 In the above-described second embodiment, the speed detector 17 is used to obtain the return speed.
In consideration of the failure of the speed detector, a configuration according to the third embodiment shown in FIG. FIG. 4 shows a configuration of an elevator control apparatus according to Embodiment 3 of the present invention, and particularly shows a configuration at the time of rescue operation. As in Embodiments 1 and 2 shown in FIGS. Parts similar to those in the conventional example shown in FIG. 6 during normal operation are partially omitted.

In FIG. 4, the same reference numerals as those in the first and second embodiments shown in FIGS. 1, 3 and 6 and the conventional example denote the same parts, and a description thereof will be omitted. As a new code, reference numeral 24 denotes a rotation speed detection circuit for obtaining a rotation speed from the current of the DC bus detected by the current detector 20. In the third embodiment, the bus voltage command circuit 23 The reference voltage is determined on the basis of the difference between the feedback speed and the speed command from the speed command generating circuit 18.

As described above, since the switching element 11a of the inverter 11 is electrically cut off, the electric power generated from the motor 1 is reduced by the diode 11b of the inverter 11.
Through the DC bus. Diode 11 at this time
Since b operates similarly to the diode converter 9 for the three-phase power supply, the voltage and current of the DC bus change as shown in FIG.

As shown in FIG. 5, the current of the DC bus generated by the electric power generated from the motor 1
It exhibits six pulsating waveforms per cycle. By monitoring the pulsation of the current of the DC bus with the rotation speed detection circuit 24 based on the value detected by the current detector 20, the electric angular velocity of the electric motor 1 can be detected. The rotation speed can be detected by dividing the angular speed. Similarly, the rotation speed of the electric motor 1 can be detected by monitoring the pulsation of the voltage of the DC bus.

As described above, by monitoring the rotation speed of the electric motor 1 irrespective of the speed detector 17 in which a failure is considered,
The car can be driven to the nearest floor more safely, and passengers can be safely rescued.

[0034]

As described above, according to the present invention, the bus voltage control circuit allows the current-carrying elements to conduct when the bus voltage exceeds the reference voltage, so that the elevator stops between floors, If the motor control system fails to start due to a failure, the brake is released with the electromagnetic contactor and the switching element of the inverter kept in the cut-off state, and the bus speed is controlled to the reference voltage or less, so that the elevator speed can be safely controlled. Since it is possible to drive to the nearest floor while maintaining the speed, passengers can be safely rescued, and the confinement rate of passengers due to failure of the motor control system can be reduced. In addition, since a safe rescue operation is realized by using the detector and the drive circuit of the conventional control device in the configuration of the rescue operation device, the rescue operation device can be configured at low cost without adding a dedicated device. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an elevator control device according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram showing braking characteristics of a permanent magnet type synchronous motor according to the present invention.

FIG. 3 is a configuration diagram showing an elevator control device according to Embodiment 2 of the present invention.

FIG. 4 is a configuration diagram showing an elevator control device according to Embodiment 3 of the present invention.

FIG. 5 is an explanatory diagram showing voltage and current waveforms of a DC bus during a rescue operation according to the present invention.

FIG. 6 is a configuration diagram showing a conventional elevator control device.

[Explanation of symbols]

1 motor (permanent magnet type synchronous motor), 2 sheave, 3
Main rope, 4 cars, 5 counterweights, 6 brakes, 7 three-phase AC power supply, 8 electromagnetic contactor, 9 converter, 10
Capacitor, 11 inverter, 11a switching element, 11b diode, 12 current detector, 13 inverter control circuit, 14 resistor, 15 conducting element, 16
Bus voltage control circuit, 17 speed detector, 18 speed command circuit, 19 speed control circuit, 20 current detector, 21
Overcurrent detection circuit, 22 bus voltage command circuit, 23 bus voltage command circuit, 24 rotation speed detection circuit, 30 weighing device.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F002 AA04 EA08 EA09 GB02 3F304 CA12 EA11 EA18 EA28 EB11 5H575 AA03 BB08 BB10 DD06 EE01 EE02 EE07 EE08 FF05 FF07 GG01 GG02 GG04 GG05 HA10 HB01 LL02 MM02

Claims (6)

[Claims] 1. A three-phase AC power supply, a converter for converting AC from the three-phase AC power supply to DC, an electromagnetic contactor for separating the three-phase AC power supply from the converter, and a DC bus side of the converter. It has a capacitor connected to smooth DC and a parallel connection of a switching element and a diode,
An inverter that converts a DC bus voltage of the converter into an AC voltage; an electric motor that drives a hoist based on an output from the inverter; and a mechanical braking force on a sheave of the hoist driven by the electric motor. A brake that is generated, a resistor and a current-carrying element that controls a current flowing through the resistor are connected in series, and are connected in parallel to the capacitor to discharge a charge voltage of the capacitor; Current detecting means for detecting a current flowing between the electric motor and an inverter control circuit for controlling a switching element of the inverter based on a current detected by the current detecting means; and An elevator control device comprising: a bus voltage control circuit for controlling a current-carrying element; In addition to employing a permanent magnet synchronous motor, the power supply further includes a bus voltage command circuit that generates a reference voltage of the bus voltage and outputs the reference voltage to the bus voltage control circuit, and the bus voltage control circuit causes the bus voltage to exceed the reference voltage. In such a case, the energizing element is made conductive, the elevator stops between floors, and when the motor control system fails and cannot be started, the electromagnetic contactor and the switching element of the inverter remain in the cut-off state. An elevator control device, wherein a brake is released and a bus voltage is controlled to be equal to or lower than a reference voltage. 2. The elevator control device according to claim 1, wherein said inverter is a voltage-type inverter. 3. The elevator control device according to claim 1, wherein the bus voltage command circuit determines the reference voltage based on an unbalanced load of a car and a counterweight and a rescue operation speed. An elevator control device characterized by the above-mentioned. 4. The elevator control device according to claim 1, wherein the bus voltage command circuit determines the reference voltage based on a difference between a rotation speed of the electric motor and a speed command. Elevator control device. 5. The elevator control device according to claim 4, wherein the rotation speed of the electric motor is detected by a pulsation of the current of the DC bus. 6. The elevator control device according to claim 4, wherein the rotation speed of the electric motor is detected by pulsation of the voltage of the DC bus.