CN101367479A - Elevator braking device - Google Patents

Abstract

The present invention provides a braking device for an elevator, which can not only further improve safety, but also reduce switching loss generated by switching elements. The braking device of the elevator comprises: a rectification circuit (2) that converts alternating current into direct current; a smoothing capacitor (3) connected to the output end of the rectification circuit; a diode (5) connected in parallel with the smoothing capacitor and a semiconductor switch (6) A series circuit; a brake winding (10) connected in parallel with a diode; a brake (11) whose braking force varies according to the electromagnetic force of the brake winding; and an arithmetic processing device (13) that generates a control command of a semiconductor switch. The device further has: a first electromagnetic contactor (7) arranged between the diode (5) and the brake winding (10); arranged between the smoothing capacitor (3) and the series circuit of the diode (5) and the semiconductor switch (6) between the second magnetic contactor (4).

Description

Elevator braking device

technical field

The present invention relates to a braking device of an elevator which controls the current flowing through the winding of the brake to perform the braking action.

Background technique

In known braking devices for elevators, a method of passing a DC voltage through a brake winding (DC electromagnet) and releasing the brake through its attractive force has been adopted. In this method, when the DC voltage is large, the impact sound generated when the brake is released increases, and when the DC voltage is small, the braking action will be delayed. For this reason, there have been proposals to control the current flowing through the brake winding by a chopper circuit using switching elements, and these methods are described in Patent Documents 1, 2 and 3. In particular, when the electromagnetic contactor is connected or abnormality occurs in the brake, the electromagnetic contactor can be opened preferably to disconnect the electric power. These methods are described in Patent Documents 1 and 2.

Patent Document 1 Japanese Patent Laid-Open Publication No. 4-96675

Patent Document 2 Japanese Patent Application Laid-Open No. 9-272664

Patent Document 3 Japanese Patent Laid-Open No. 2003-81543

Recently, safety requirements are increasing, but in the above-mentioned known techniques, no consideration is given to constructing a cutoff circuit of a multiple system. Specifically, in the proposals described in Patent Documents 2 and 3, although the electromagnetic contactor is connected between the switching element and the brake winding, it still needs to cut off the power when the contact is welded, for example.

In addition, another control method has been proposed, which compares the command value and the detected value, and turns on the chopper circuit when the former is large, and turns off the chopper circuit when the former is small, in order to improve reliability. , or use the carrier to compare the command value, and repeatedly turn on (ON) / off (OFF) action, but in the above schemes will lead to the increase of the switching times of the chopper circuit, which may increase the loss of the switch big.

Contents of the invention

An object of the present invention is to provide an elevator braking device capable of further improving safety and reducing switching loss occurring in switching elements.

In order to solve the above problems, the present invention provides a brake device for an elevator, which includes: a rectifier circuit for converting alternating current into direct current; a smoothing capacitor connected to the output end of the rectifier circuit; a series circuit of a diode and a semiconductor switch connected in parallel to a smoothing capacitor; a brake winding connected in parallel to the diode; a brake whose braking force varies according to an electromagnetic force of the brake winding; and an arithmetic process for generating a control command for the semiconductor switch device, wherein the brake device of the elevator further has: a first electromagnetic contactor arranged between the diode and the brake winding; a first electromagnetic contactor arranged between the smoothing capacitor and the series circuit of the diode and the semiconductor switch Between the second magnetic contactor.

Invention effect

According to the present invention, due to the duplication of electromagnetic contactors, the brake device for elevators of the present invention can not only further improve safety, but also reduce switching losses of switching elements through extremely simple control, thereby realizing energy saving. .

Description of drawings

Fig. 1 is a structural diagram showing a first embodiment of the present invention.

Fig. 2 is an example when the magnetic contactor is installed in another position.

Fig. 3 is a schematic diagram of a known braking device.

Figure 4 is an example of the current flow through the brake winding in a known braking device.

Fig. 5 is an example of the current flowing through the brake winding in the first embodiment.

Fig. 6 is an enlarged view of an example of the current flowing through the brake winding in the first embodiment.

Fig. 7 is a structural diagram showing a second embodiment of the present invention.

Symbol Description

1 AC power supply

2 rectifier circuit

3 smoothing capacitor

4 The second magnetic contactor

5 diodes

6 semiconductor switch

7 The first electromagnetic contactor

8 current detector

9 resistors

10 Brake winding

11 brake

12 electric motor (hoist)

13 Operation processing device

14 DC power supply

15 switch

16 Transformers

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings.

first embodiment

Fig. 1 is the braking device of the elevator of the first embodiment of the present invention, and the braking device of this elevator comprises: AC power source 1; Convert described AC power source 1 into the rectifying circuit 2 of direct current; Connect in described rectifying circuit 2 A smoothing capacitor 3 at the output end; a diode 5; a semiconductor switch 6 connected in series on the anode side of the diode 5; a brake winding 10 connected at one end to the anode side of the diode 5; with the other end of the brake winding 10 and the cathode side of the diode 5 The first electromagnetic contactor 7 connected and performing switching operation; the current detector 8 connected between the first electromagnetic contactor 7 and the brake winding 10; the resistor 9 connected in parallel with the brake winding 10; the positive electrode connected to the smoothing capacitor 3 between the cathode side of the diode 5 and between the negative side of the smoothing capacitor 3 and one end of the semiconductor switch 6, and the second electromagnetic contactor 4 that performs switching operations; it is driven by a power converter not shown and used as an elevator lift The motor 12 of the power of the action; the brake 11 that performs the braking action of the motor 12; generates and outputs the command of the semiconductor switch 6 according to the current signal obtained from the current detector 8, and when the motor 12 stops normally and abnormally stops The arithmetic processing unit 13 issues a contact opening command to the first electromagnetic contactor 7, the second electromagnetic contactor 4, and the like.

The brake 11 applies a braking action to the motor 12 by pressing a brake pad using a spring force or the like. Furthermore, in the brake 11 , an electromagnetic force is generated by passing a current (hereinafter referred to as a winding current) through the brake winding 10 , and the brake pad is attracted by the electromagnetic force, whereby the braking operation can be released. When the semiconductor switch 6 is turned on while the contacts of the first electromagnetic contactor 7 and the second electromagnetic contactor 4 are closed, power is supplied from the smoothing capacitor 3 to the brake winding 10 to cause winding current to flow. At this time, the amount of current can be adjusted by performing on/off control of the semiconductor switch 6 . That is, when the semiconductor switch 6 is turned on, power is supplied from the smoothing capacitor 3 , and the winding current flows through the brake winding 10 and the semiconductor switch 6 . On the other hand, when the semiconductor switch 6 is turned off, the winding current flowing through the brake winding 10 flows in the circuit returning to the diode 5, and proceeds with a time constant determined by the inductance component and resistance component of the brake winding 10 and the resistor 9, etc. attenuation.

When the elevator is stopped during normal operation, or when an emergency stop occurs due to an abnormality in the system, the contact of the electromagnetic contactor is opened to cut off the power supply. The feature of the first embodiment is to improve safety by using two electromagnetic contactors to form a double system. The first electromagnetic contactor 7 is connected between the diode 5 and the brake winding 10, and when the contact is opened, the winding current flows only in the circuit between the brake winding 10 and the resistor 9, so that the power supply can be cut off. The second electromagnetic contactor 4 is connected between the smoothing capacitor 3 and the diode 5 and between the smoothing capacitor 3 and the semiconductor switch 6 , and by opening these contacts, the power supply from the smoothing capacitor 3 can also be blocked.

Fig. 2 is an example when the electromagnetic contactor is installed in another position. In this example, the second electromagnetic contactor 4 is provided between the rectifier circuit 2 and the smoothing capacitor 3 . At this time, even if the second electromagnetic contactor 4 is turned off, the residual electric charge of the smoothing capacitor 3 can still supply power, so duplication cannot be completely realized. Therefore, it is important to connect the second electromagnetic contactor 4 between the smoothing capacitor 3 and the diode 5 and between the smoothing capacitor 3 and the semiconductor switch 6 as shown in the first embodiment, whereby even one electromagnetic contactor 4 can be obtained. If the contactor fails, for example, when welding occurs, the power supply can also be cut off through another electromagnetic contactor.

The driving operation of the magnetic contactor will be described below. When the stop operation is performed during normal operation, the arithmetic processing device 13 outputs an instruction in the state where the contacts of the first electromagnetic contactor 7 are closed, and at the same time outputs the opening instruction of the semiconductor switch 6 and the contact of the second electromagnetic contactor 4. Open instruction. At this time, since the opening operation speed of the semiconductor switch 6 is faster than the opening operation speed of the second electromagnetic contactor 4, the burden on the second electromagnetic contactor 4 is small, so that the contact capacity (rated voltage and rated current, etc.) can be used small device. On the other hand, at the time of an abnormal stop operation such as an emergency stop, first, the contacts of the first electromagnetic contactor 7 are urgently opened. The first electromagnetic contactor 7 may have a mechanism that directly receives an open signal from an external device other than the arithmetic processing device 13 that can detect an abnormality in the elevator system. Thereafter, the semiconductor switch 6 is turned off, and the contact of the second electromagnetic contactor 4 is also opened. In this process, since an excessive voltage may be generated in the first electromagnetic contactor 7, it is necessary to use an electromagnetic contactor with a large contact capacity. That is, the feature of the first embodiment is that the contact capacity of the first electromagnetic contactor 7 is larger than the contact capacity of the second electromagnetic contactor 4, so that the electromagnetic contactor can be operated in consideration of the stop operation. The effect of optimizing the contact capacity.

The ON/OFF control of the switching element will be described below. FIG. 3 is a schematic diagram of a known braking device configured such that a DC power supply 14 is connected via a switch 15 to a brake winding 10 and a resistor 9 connected in parallel. In the known braking device, the brake is released by switching on the switch 15 so that the winding current iL flows through the brake winding 10 . Fig. 4 is an example diagram of currents flowing through a brake winding in a known braking device. A quick response is required when the brake is released. At this time, by increasing the voltage value of the DC power supply 14 in FIG. 3, as shown in the current example 1 of FIG. 4, the winding current iL can be rapidly increased (rising time t1). However, at this time, since the amplitude i1 of iL increases and the electromagnetic attractive force also increases accordingly, there is an adverse effect of increasing the rattling sound of the brake pad when the brake is released. On the other hand, in order to suppress the crashing noise, by reducing the voltage value of the DC power supply 14 in FIG. 3, as shown in the current example 2 of FIG. 4, the amplitude i2 of the winding current iL can be suppressed, and the electromagnetic attractive force can be reduced. However, since the rise time t2 becomes longer at this time, there is an adverse effect that the response speed of the brake decreases. Therefore, in the first embodiment, by performing ON/OFF control of the switching element, it is possible to simultaneously increase the response speed of the brake and prevent the increase of the crashing sound.

Fig. 5 is an example of the current flowing through the brake winding in the first embodiment, the dotted line in the figure represents the current command value, and the solid line represents the current actually flowing through the brake winding. In the first embodiment, through control, the DC voltage is increased to achieve a fast rise time, and the on/off control is started after the impact sound reaches a small level (for example, the amplitude of the winding current is i2, etc.), by Therefore, a large increase in winding current can be avoided. And, generally speaking, the electromagnetic force required to maintain the attracted brake pad is smaller than the electromagnetic force required to attract the brake pad, so the current command value is reduced after the brake pad is attracted. Thereby, energy saving can be achieved especially when it is applied to a direct elevator with a high lift.

FIG. 6 is an enlarged view of a portion surrounded by a dashed line in FIG. 5 . In the first embodiment, the current command value is set to a value greater than the winding current value (minimum holding current) required to generate the minimum electromagnetic force for holding the brake pad, for example, when a plurality of brake windings are connected in parallel When connected together as a brake winding 10, the current command value is set to be roughly equal to the value of the sum of the minimum holding currents of each brake winding plus the variable error part, and only when the winding current is lower than the current command value, the semiconductor The switch 6 is turned on for a certain time T. In a known control method of a semiconductor switch, a method of comparing a command value with a detection value, turning on the semiconductor switch when the former is large, and turning off the semiconductor switch when the former is small, or using a carrier wave This method compares command values and repeats ON/OFF operation. However, when the former method is adopted, the number of switching operations of the semiconductor switch 6 may increase near the boundary point, resulting in increased switching loss. In addition, in the latter method, if the frequency of the carrier is low, it may cause the fluctuation range of the winding current to increase, so that it is lower than the minimum holding current, so the frequency is generally set higher, but the frequency After the increase, it may lead to an increase in the number of switches and an increase in switching losses. Compared with this, in the first embodiment, since the semiconductor switch 6 is turned on for a certain time T only when the winding current is lower than the current command value, in addition to the extremely simple control method, the number of switching times can also be reduced, so There is an effect of being able to reduce switching loss.

In the first embodiment, the AC power source 1 is rectified by the rectifier circuit 2 to generate a DC voltage, but a structure in which the DC power source is directly connected to the smoothing capacitor can also be used, and the same effect can be obtained in this case.

second embodiment

Fig. 7 is the elevator of the second embodiment of the present invention, it is characterized in that a transformer 16 is set between the AC power supply 1 and the rectifying circuit 2 of the first embodiment of Fig. 1 for insulation. Generally, in an elevator system, a commercial AC power supply 1 is converted by a transformer 16 to generate and use a plurality of voltages (for example, a main circuit voltage and a control voltage, etc.). At this time, since the secondary side of the transformer 16 is insulated, it is a general method to perform processing such as grounding with the negative side of the smoothing capacitor 3 as a reference point. At this time, with the contact of the first electromagnetic contactor 7 and the second electromagnetic contactor 4 closed and the semiconductor switch 6 turned on, one end of the brake winding 10 has the same potential as the reference point. In terms of the installation position of the current detector 8, when a ground fault occurs in the brake winding 10 under the above conditions, an excessive short-circuit current will flow. If the current detector 8 is set at the potential of the reference point Between the anode side of the diode 5 and the brake winding 10, no short-circuit current may be detected. That is, from the perspective of facilitating the operation of the brake, the current detector 8 can be arranged between the cathode side of the diode 5 and the brake winding 10, or between the anode side of the diode 5 and the brake winding 10, but as in the second As shown in the embodiment, by setting it between the cathode side of the diode 5 and the brake winding 10, which is not the potential of the reference point, it is also possible to detect the short-circuit current when a ground fault occurs in the brake winding 10, so it has the advantage of improving safety. Effect.

In the second embodiment, the same effect can be obtained by disposing the current detector 8 between the anode side of the diode 5 and the brake winding 10 when the positive side of the smoothing capacitor 3 is used as a reference point. That is, the current detector may be installed between the terminals of the brake winding 10 that are not electrically connected to the reference point and the diode 5 . It goes without saying that in the second embodiment, part of the AC power supply 1 , the transformer 16 and the rectifier circuit 2 may be a DC isolated voltage source, and in this case, the same effect can also be obtained.

Claims (6)

1. the brake equipment of an elevator, the brake equipment of this elevator comprises: alternating current is transformed to galvanic rectifying circuit; Be connected the smooth condenser of the mouth of described rectifying circuit; The diode that is connected in parallel with described smooth condenser and the circuit series of semiconductor switch; The drg winding that is connected in parallel with described diode; The drg that braking force changes according to the electromagnetic force of described drg winding; And the arithmetic processing apparatus that generates the control command of described semiconductor switch, the brake equipment of this elevator is characterised in that further to have:

Be arranged on the 1st electromagnetic contactor between described diode and the described drg winding;

Be arranged on the 2nd electromagnetic contactor between the circuit series of described smooth condenser and described diode and semiconductor switch.

2. the brake equipment of an elevator, the brake equipment of this elevator comprises: direct voltage source; Be connected the smooth condenser of the mouth of described direct voltage source; The diode that is connected in parallel with described smooth condenser and the circuit series of semiconductor switch; The drg winding that is connected in parallel with described diode; The drg that braking force changes according to the electromagnetic force of described drg winding; And the arithmetic processing apparatus that generates the control command of described semiconductor switch, the brake equipment of this elevator is characterised in that further to have:

Be arranged on the 1st electromagnetic contactor between described diode and the described drg winding;

Be arranged on the 2nd electromagnetic contactor between the circuit series of described smooth condenser and described diode and semiconductor switch.

3. as the brake equipment of claim 1 or 2 described elevators, it is characterized in that,

The rated capacity of the contact in described the 1st electromagnetic contactor is greater than the rated capacity of the contact in the 2nd electromagnetic contactor.

4. the brake equipment of elevator as claimed in claim 1 is characterized in that,

Normal in service when stopping to move, described arithmetic processing apparatus is output command under the contact closing state of described the 1st electromagnetic contactor, and exports the open instruction of the contact of the open command of described semiconductor switch and described the 2nd electromagnetic contactor.

5. the brake equipment of elevator as claimed in claim 1 is characterized in that,

Described the 1st electromagnetic contactor and described the 2nd electromagnetic contactor can be controlled the switch of contact by described arithmetic processing apparatus, and the contact of described the 1st electromagnetic contactor can be by opening the external device (ED) that detects unusually of elevator device.

6. the brake equipment of elevator as claimed in claim 1 is characterized in that,

In promptly stopping, carrying out improperly when stopping to move, make the contact of described the 1st electromagnetic contactor open, described semiconductor switch is disconnected, and make the contact of described the 2nd electromagnetic contactor open.

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