JPH0225819Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an elevator control device, and is particularly effective for improving the ride comfort of an AC elevator when landing on the floor.

[Conventional technology and problems]

Conventionally, in AC elevators that are operated by driving the elevator with an induction motor, the car is decelerated by DC braking upon landing on the floor, and the electromagnetic brake is activated when the car reaches almost zero speed. It is. However, as is well known, DC braking torque becomes extremely small as it approaches zero speed, so according to the above method, a large braking torque is required, especially when descending with full load or rising with no load. During maximum unloading operation, a large amount of DC braking current flows just before landing, and it is difficult to bring the car to a complete standstill with DC braking torque. This caused a problem in that a stop shock occurred.

[Means for solving problems]

The present invention was developed to solve the above problems, and includes a brake command generation circuit that issues a brake command when the car reaches a predetermined distance before the landing level, and a brake command generation circuit that issues a brake command when the car reaches a predetermined distance from the landing level. It is equipped with a brake timing setting circuit that sets the delay time until the electromagnetic brake is activated, and furthermore, the delay time is changed according to the load condition of the car, i.e., the maximum when the load is lowered at full load or when the load is raised with no load. During unloading operation, the delay time is shortened so that the DC braking torque when the brake is applied is almost equal to the brake torque, and during maximum lifting operation when full load is raised or no load is lowered, the electromagnetic brake is activated after the car is stationary. The feature is that the delay time is set large as shown in FIG.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing the overall configuration of the present invention, in which 1 is a commercial power source, 3 is an induction motor that drives an elevator car (not shown), 4 is an electromagnetic brake, and 2 is a motor control circuit. For example, it is constituted by a device that generates power running torque or braking torque in the induction motor 3 according to the deviation between the elevator speed command and the speed feedback signal. 5 is a brake command circuit which issues a brake command when the car reaches a predetermined distance before the landing level. Reference numeral 6 denotes a brake timing setting circuit that delays the brake command by a time corresponding to the load information within the car. 7 is a brake control circuit that operates the electromagnetic brake 4 in response to a brake command; 8 is a load detection device that detects the load inside the car; 9 is a load information circuit that converts the load inside the car into an output pattern to be described later; 10 is a This is a current zero hold command circuit that issues a command to zero the current supplied to the induction motor 3 after the electromagnetic brake 4 is activated.

FIG. 2 is a diagram showing an output pattern of the load information circuit 9 that converts a load signal into a corresponding voltage signal, where a shows the output pattern during upward operation and b shows the output pattern during downward operation, respectively. For example full load
The output voltage during rising operation at W ₁ is V ₂ ,
During descending operation, it becomes V ₁ . W ₀ indicates the load during balance. The larger the output voltage from the load information circuit 9, the larger the delay time of the brake timing setting circuit 6 is set.

The operation will be described below when the full load is lowered.

When the full load is lowered, the load information circuit 9 outputs a signal of voltage V ₁ as shown in FIG. 2, and the brake timing setting circuit 6 sets a delay time t ₁ accordingly. When the car reaches a position a predetermined distance before the landing level, a brake command is output from the brake command circuit 5, and this is input to the brake control circuit ₇ after a delay of a predetermined time t1 in the brake timing setting circuit 6, and the brake is activated. Operate.
Here, since the change in DC braking torque and the set torque of the electromagnetic brake when the full load is lowered after the brake command is generated can be obtained in advance, by setting the delay time _t1 appropriately, the electromagnetic brake is activated. DC braking torque and brake torque can be made equal.

On the other hand, the brake command and load information are input to the current zero hold command circuit 10, and a current zero hold command is output to the motor control circuit 2 at a delay time _{t1 '} , which is slightly larger than the delay time t1, and the induction motor 3
Cut the current supplied to the That is, after the electromagnetic brake 4 is completely operated, the current supplied to the induction motor 3 is cut off, and the car stops. As a result, during full-load descending operation, the electromagnetic brake operates while the car is moving at a low speed, but at this time, the brake torque and the DC braking torque are approximately equal, and the brake torque is supplied after time t ₁ '. Since the current is cut and the DC braking torque is reduced to zero, shock almost never occurs.

FIG. 3 shows how the deceleration and DC braking current change from the start of deceleration to the stop during this full-load descending operation.

Note that the same operation as above occurs also in the case of no-load upward operation. In other load conditions, the braking torque is not as large as in _the above case when landing on the floor, so it is easier to keep the car stationary. The shock upon landing is reduced by activating the electromagnetic brake after the robot has come to a complete standstill.

FIG. 4 is a diagram corresponding to FIG. 3 during full load rising operation, and the DC braking current is not shown. The reason why the drive current flows before and after the brake command is to prevent reversal caused by the load and to hold the car in a stationary state. When the total load increases, as can be seen from FIG. 2, the load information circuit 9 outputs a signal of voltage _V2 , and a delay time _t2 corresponding to the signal is set. This delay time t ₂ is sufficiently longer than the aforementioned t ₁ , and during this time the car is held completely stationary by the drive current, and the electromagnetic brake 4 is activated after the delay time t ₂ . Thereafter, after t ₂ ', which is set slightly longer than the delay time t ₂ as in the case described above, has elapsed, the current supplied to the induction motor is cut off by the current zero hold command.

In this way, when the full load increases, the delay time t ₂ is reduced to t ₁
By making it larger, the electromagnetic brake can be activated after the car has come to a complete standstill.

[Effect of idea]

According to the present invention, during maximum unloading operation in which it is difficult to keep the car completely still, the electromagnetic brake is activated when the DC braking torque becomes equal to the brake torque, so that excessive DC It is possible to prevent braking current from flowing and to minimize the shock caused by the operation of the electromagnetic brake. In addition, in other load conditions where the required braking torque is small, the shock at a stop can be minimized by operating the electromagnetic brake after the car is as close to a standstill as possible, or when the car is completely stationary. can be made smaller.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention;
Figure 2 is a diagram showing the output pattern of the load information circuit.
FIG. 3 is a diagram showing the timing of braking during full-load descending operation, and FIG. 4 is a diagram showing the braking timing during full-load increasing operation. 1...Commercial power supply, 2...Motor control circuit, 3...
... Induction motor, 4 ... Electromagnetic brake, 5 ... Brake command circuit, 6 ... Brake timing setting circuit, 7 ... Brake control circuit, 8 ... Load detection device, 9 ... Load information circuit, 10 ... Current Zero hold command circuit.

Claims (1)

[Scope of utility model registration request] In an AC elevator control device, the elevator is driven by an induction motor, and the car is decelerated by DC braking upon landing on the floor.A brake command is issued when the car reaches a predetermined distance below the landing level. A brake command generation circuit,
The load detection device detects the load condition inside the car, and the delay time from the brake command to when the electromagnetic brake actually operates is designed so that the DC braking torque when the brake is activated is almost equal to the brake torque during maximum unloading operation. 1. A control device for an AC elevator, comprising: a brake timing setting circuit that sets a small brake timing and sets a large brake timing so that an electromagnetic brake is activated after a car comes to a standstill during maximum lifting operation.