CN116177338A - Star-sealing loop detection method - Google Patents

Abstract

The invention discloses a star-sealing loop detection method, which is characterized in that in the processes of elevator brake release and speed-controllable operation, a flag allowing star-sealing detection is made according to load information of an elevator or current or voltage or power or torque information output by a frequency converter; when the frequency converter receives the command of stopping output and allowing star sealing detection, the frequency converter performs electronic star sealing to form a follow current path between the frequency converter and the elevator host; under the condition that the elevator host is in a follow current state based on the follow current path, the elevator control system controls the star sealing contactor to seal a star for the elevator host; and the elevator control system determines a star sealing loop detection result based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor. The invention can avoid the condition of missing detection and false detection in the traditional detection mode, thereby reliably and accurately judging the effectiveness of the star-sealing loop.

Description

Star-sealing loop detection method

Technical Field

The invention relates to the technical field of elevator detection, in particular to a star-sealing loop detection method.

The background technology is as follows:

with the development of elevator technology, the safety requirement on the elevator is higher and higher, in order to ensure that the elevator can effectively reduce or limit the elevator sliding speed, three-phase input of a short-circuit motor is generally adopted, and the braking force generated by a permanent magnet of a permanent magnet synchronous motor (PM motor) is utilized to reduce or limit the elevator sliding speed (namely, the star sealing technology).

The current common star sealing method for the elevator control system adopts a star sealing contactor, and a normally closed star sealing contactor is added between a frequency converter and a motor to realize three-phase input of a short-circuit motor.

In general, an elevator control system detects a star sealing function through an auxiliary contact of a star sealing contactor, however, when only the star sealing contactor is detected, if the star sealing contactor is damaged, the star sealing contactor is not replaced or a circuit is manually changed for various reasons, and an action signal of other contactors is connected to the detection port, the monitoring point does not actually detect the action condition of the star sealing contactor. Or when the U or V or W line or short wire connected to the main contact of the star sealing contactor is removed or the line is interrupted, the actual star sealing function does not exist although the contactor is operated.

The invention discloses a detection method and a detection device for a star-sealing contactor for an elevator, which are disclosed in Chinese patent application publication No. CN114415007A, and are used for releasing a brake (namely, a band-type brake is opened) to slide when the elevator is stopped, and judging whether a star-sealing function is qualified or not by judging whether a preset speed or acceleration is exceeded in a preset time. However, the method needs to release the brake (i.e. release the brake and open the band-type brake) to slide, so that a certain risk exists, whether a person exists in the carriage or not needs to be judged, and the acquisition of the preset time and the preset speed of the method is complex.

In addition, chinese patent application publication No. CN114715749a discloses an automatic detection method, system, device and storage medium for a star-sealing function of an elevator, where the automatic detection method for a star-sealing function of an elevator is applied to a control system of an elevator, and when a star-sealing function detection instruction is detected, target service floor information of the elevator is obtained, and after an elevator car is controlled to run to a target floor corresponding to the target service floor information, a star-sealing module is controlled to take effect, so that the elevator car enters a car sliding state, a car sliding speed or a car sliding distance of the elevator car in the car sliding state is obtained, and whether the star-sealing function of the elevator meets a preset requirement is determined based on the car sliding speed or the car sliding distance. The method also needs to release the brake (namely, release the brake and open the band-type brake) to slide, so that a certain risk exists, and in addition, the detection time is long, so that the riding of passengers is influenced.

In addition, chinese patent application publication No. CN115231404a discloses a star-sealed circuit detection method, apparatus, elevator control system, and storage medium. The method is applied to an elevator control system, and the elevator control system is used for controlling and detecting a star-sealing loop; when the elevator is in a static state, the elevator control system controls the frequency converter to conduct a power supply loop between a power supply and an elevator host, and inputs detection current to the elevator host; under the condition that the detected current reaches a preset current value, the elevator control system controls the frequency converter to close a power supply loop between the power supply and the elevator host machine, so as to form a follow current path between the frequency converter and the elevator host machine; under the condition that the elevator host is in a follow current state based on the follow current channel, the elevator control system controls the star sealing contactor to seal the star of the elevator host; the elevator control system determines the detection result of the star sealing loop based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor, and completely simulates the current effect of the star sealing loop before and after the star sealing action of the star sealing contactor by a nondestructive means, so that the effectiveness of the star sealing loop can be reliably and accurately judged. However, this method requires an ON-OFF star seal contactor when a detection current is input, which affects the life of the contactor and increases the noise when the contactor is operated.

The invention comprises the following steps:

in order to solve the problems, the invention aims to provide the star-sealing loop detection method for the defects of the detection of the star-sealing loop of the elevator, which can avoid the condition of missing detection and false detection in the traditional detection mode, thereby reliably and accurately judging the effectiveness of the star-sealing loop and further improving the safety performance of the elevator. The invention can integrate the detection of the star sealing loop into the normal stop time sequence, thereby not affecting the service life of the elevator and the star sealing contactor of passengers and not increasing noise.

In order to achieve the above object, the invention provides a star-sealing loop detection method applied to an elevator control system, which is characterized in that the star-sealing loop comprises a frequency converter, a star-sealing contactor and an elevator host, wherein the frequency converter is connected with the elevator host provided with the star-sealing contactor; the star-sealing loop detection method comprises the following steps:

in the elevator brake release and speed controllable operation, a flag allowing star-sealing detection is made according to load information of an elevator or current or voltage or power or torque information output by a frequency converter;

when the frequency converter receives the command of stopping output and allowing star sealing detection, the frequency converter performs electronic star sealing to form a follow current path between the frequency converter and the elevator host;

under the condition that the elevator host is in a follow current state based on the follow current path, the elevator control system controls the star sealing contactor to seal a star for the elevator host;

and the elevator control system determines a star sealing loop detection result based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor.

In a preferred embodiment of the present invention, further comprising: detecting the output current of the frequency converter; under the condition that the detected current reaches a preset current value, a flag allowing star-sealing detection is made

In a preferred embodiment of the present invention, the star-sealing loop detection result includes a normal detection result and an abnormal detection result;

the normal detection result is judged by adopting the following method: if the follow current meets a preset condition, the elevator control system determines that the star-sealing loop detection result is a normal detection result; the preset condition comprises that the value of the follow current is zeroed along with the star sealing action of the star sealing contactor;

the abnormality detection result is judged by the following method: and if the follow current does not meet the preset condition, the elevator control system determines that the star-sealed loop detection result is an abnormal detection result.

Due to the adoption of the technical scheme, the invention can avoid the condition of missing detection and false detection in the traditional detection mode, thereby reliably and accurately judging the effectiveness of the star-sealing loop and further improving the safety performance of the elevator. The invention can integrate the detection of the star-sealing contactor into the normal stop time sequence, thereby not affecting the elevator of passengers, prolonging the service life of the star-sealing contactor and not increasing noise.

Drawings

Fig. 1 is a schematic diagram of the connection principle among a frequency converter, a star seal contactor and a motor.

FIG. 2 is a schematic diagram of a detection flow of the star-sealed circuit detection method of the present invention.

Fig. 3a to 3c are schematic diagrams illustrating the formation of a current loop before stopping the star-sealing loop detection method according to the present invention.

Fig. 4 is a schematic diagram illustrating formation of a freewheel loop in the star-sealed loop detection method of the present invention.

Fig. 5 is a schematic diagram of star sealing of a star sealing contactor according to the star sealing loop detection method of the present invention.

FIG. 6 is a second schematic diagram of a detection flow of the star-sealed loop detection method of the present invention.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description.

The star-sealing loop detection method is applied to an elevator control system, and referring to fig. 1, the star-sealing loop comprises a frequency converter, a star-sealing contactor and an elevator host, wherein the frequency converter is connected with the elevator host provided with the star-sealing contactor.

Referring to fig. 2, the star-sealing loop detection method includes the following steps:

step S210, detecting the output current of a frequency converter in the elevator brake release and speed controllable operation;

step S220, under the condition that the detected current reaches a preset current value, a flag allowing star-sealing detection is made;

step S230, when the frequency converter receives the instruction of stopping output and allows star sealing detection, the frequency converter performs electronic star sealing to form a follow current path between the frequency converter and the elevator host;

specifically, as in the chinese patent application publication No. 114778991a, waveforms of output torque of an elevator main machine (the output torque of the elevator main machine is positively correlated with the output current of a frequency converter) at different stages and relationships with load percentages, moment of inertia, acceleration, deceleration, and the like are shown in the running of the elevator. When the frequency converter receives the command of stopping output, the current is basically in certain relation with the current in acceleration and deceleration when the frequency converter starts zero speed, high speed and uniform speed and stops zero speed. In some examples, when the load is 0% (i.e., empty car, no passengers), its elevator car output current is about 75% of the elevator car rated current, and the elevator car output current can be made larger, such as 100% of the elevator car rated current, by injecting the excitation current Id.

As shown in fig. 1, the driving signals of the controllable switching transistors T1, T2, T3 (such as IGBTs) of the upper bridge arm of the frequency converter are blocked (i.e. disabled, the controllable switching transistors are turned off), while the driving signals of the controllable switching transistors T4, T5, T6 (such as IGBTs) of the lower bridge arm are always enabled, or the driving signals of the controllable switching transistors T4, T5, T6 (such as IGBTs) of the lower bridge arm of the frequency converter are blocked, while the driving signals of the controllable switching transistors T1, T2, T3 (such as IGBTs) of the upper bridge arm are always enabled, so that the electronic star sealing in the prior art can be realized.

Since the drive signal of one of the legs of the frequency converter is always blocked, the bus voltage in fig. 1 is prevented from providing drive energy to the elevator car, in which case the elevator car cannot generate a torque other than in combination with braking, and thus "electronic star sealing" is a safe electric brake. In the electronic star-sealing process, due to the follow current action of the coil of the elevator host, follow current can be realized through a follow current channel formed by the follow current diode of the elevator host and the frequency converter and the controllable switch tube, and the follow current in the star-sealing loop gradually decreases from an initial current value.

In some examples, if the U-phase current of the inverter is positive and the V, W-phase current of the inverter is negative (the phase current of the inverter is positive to the elevator car) when the inverter receives the stop output command, the instantaneous current path may be as shown in fig. 3a (through T1, T5, T6) or fig. 3b (T1, D2, T6) or fig. 3c (T1, D2, D3) or fig. 4 (D4, T5, T6) because the voltage of the elevator car is PWM modulated by the bus voltage Ud. When the controllable switching tubes T1, T2, T3 of the upper bridge arm of the frequency converter are turned off and the controllable switching tubes T4, T5, T6 of the lower bridge arm of the frequency converter are turned on, the freewheel path becomes as shown in fig. 4.

The flag for allowing star detection made in step S210 and step S220 may be made based on the load information (load) of the elevator, or information such as voltage, power, or torque output from the inverter.

Step S240, when the elevator host is in a freewheel state based on the freewheel path, the elevator control system controls the star-sealing contactor to seal a star for the elevator host.

In particular, since the elevator host relies on the freewheeling diodes D1, D2, D3, D4, D5, D6 of the frequency converter and the controllable switching tubes T1, T2, T3, T4, T5, T6 for freewheeling times of only tens of milliseconds to hundreds of milliseconds, the main contact KM2 of the star-seal contactor must be closed for the duration of this freewheeling state, otherwise the test will fail; in addition, the star sealing action of the star sealing contactor has an error of about 10 milliseconds; the electronic star sealing of the frequency converter is matched with the star sealing of the contactor controlled by the elevator control system to seal the star of the elevator host, so that the star sealing action of the star sealing contactor is realized under the condition that the elevator host is in a follow current state.

In some examples, the electronic star seal may be performed by the frequency converter at time T1 after the elevator control system drives the star seal motion of the star seal contactor. For example, the T1 time may range from 0ms to 15ms, with a suggested T1 time value of 5ms.

It should be noted that in step S230, if all the switching tubes are turned off, or if only the switching tubes of the upper bridge arm are turned off in fig. 3c, the freewheeling time is greatly shortened due to the fact that the freewheeling circuit introduces the bus voltage Ud, which may result in a test failure.

And step 250, the elevator control system determines a star sealing loop detection result based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor.

Specifically, after the frequency converter performs electronic star sealing, a star sealing contactor performs contactor star sealing on an elevator host; the elevator control system determines a star-sealing loop result based on the flow change of the follow current generated by the coil of the elevator host before and after the star-sealing action of the star-sealing contactor. As shown in fig. 5, the broken line is the freewheel current after the main contact KM2 of the star-sealing contactor is closed, and compared with fig. 4 and 5, if the star-sealing loop is normal, the freewheel current does not flow through the frequency converter but only flows through the elevator host and the star-sealing contactor after the star-sealing contactor successfully completes the star-sealing action; the elevator control system can determine the detection result of the star sealing loop based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor; if the change of the follow current before and after the star sealing action meets the rule, the normal star sealing loop can be determined, and the effective star sealing can be realized; otherwise, the star sealing loop is abnormal, and effective star sealing cannot be realized. The freewheel current of the star-closed loop may comprise the phase current at the output of the frequency converter in case the elevator main machine is in freewheel state. Detecting phase current at the output end of the frequency converter, and if the star sealing loop is effective, zeroing the phase current value at the output end of the frequency converter along with star sealing action of the star sealing contactor; if the star-sealed loop is invalid, the phase current value at the output end of the frequency converter cannot appear. And determining the star-sealing loop detection result according to the change of the phase current value of the output end of the frequency converter.

The star-sealing loop detection result comprises a normal detection result and an abnormal detection result;

the normal detection result is judged by the following method: if the follow current meets a preset condition, the elevator control system determines that the star-sealing loop detection result is a normal detection result; the preset condition comprises that the value of the follow current is zeroed along with the star sealing action of the star sealing contactor;

the abnormality detection result is judged by the following method: and if the follow current does not meet the preset condition, the elevator control system determines that the star-sealed loop detection result is an abnormal detection result.

Specifically, as shown in fig. 5, the broken line is the freewheel current after the main contact KM2 of the star-sealing contactor is closed, comparing fig. 4 and fig. 5, if the star-sealing loop of the contactor is normal, the freewheel current at the output end of the frequency converter is not zero before the star-sealing action of the contactor, after the star-sealing action of the star-sealing contactor is successfully completed, the freewheel current is not flowing through the frequency converter due to the three-phase short circuit of the star-sealing contactor by the elevator host, and the elevator control system can determine the detection result of the star-sealing loop according to whether the phase current at the output end of the frequency converter meets the phenomenon that the value of the phase current suddenly returns to zero along with the star-sealing action of the star-sealing contactor; if the change of the follow current at the output end of the frequency converter before and after the star sealing action meets the preset condition, the normal star sealing loop can be determined, and the effective star sealing can be realized; otherwise, the star sealing loop is abnormal, and effective star sealing cannot be realized. In the case where the detected freewheel current is sufficiently small, the freewheel current may be considered to be zeroed, for example, in the case where the freewheel current is smaller than a preset zeroing threshold (the preset zeroing threshold may be close to zero instead of zero).

In some examples, as shown in fig. 6, firstly, judging whether the elevator is in the brake release and speed controllable operation, and if the elevator is in the brake release and speed controllable operation, detecting the output current of the frequency converter; judging whether the output current reaches a preset A value or not; if the output current reaches a preset A value, setting a flag allowing the star-sealing detection of the contactor; when the frequency converter receives the command of stopping output, judging whether the star-sealing detection of the contactor is allowed; if the frequency converter receives the output stopping instruction and allows star sealing detection, the frequency converter performs electronic star sealing and drives the attraction star sealing contactor (the attraction star sealing contactor can be driven to perform electronic star sealing again in order to ensure that the star sealing contactor acts under the condition that the freewheel path is in the freewheel state in consideration of the action time of the star sealing contactor being longer than the action time of the frequency converter); starting a timer; judging whether the output current is quickly zeroed before the timer reaches the preset value B, if so, turning off all the controllable switching tubes T1, T2, T3, T4, T5 and T6, clearing a star-seal-allowed detection flag, and outputting normal function information of the star-seal contactor; if the output current does not return to zero rapidly when the timer reaches the preset value B, all the controllable switching tubes T1, T2, T3, T4, T5 and T6 are turned off, the star-seal-allowed detection flag is cleared, and the star-seal contactor abnormal function information is output.

It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these are merely examples of one driving phase sequence, and multiple phase sequences and current forms may be actually controlled, and are not necessarily sequentially executed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

Claims (3)

1. The star-sealing loop detection method is applied to an elevator control system and is characterized in that the star-sealing loop comprises a frequency converter, a star-sealing contactor and an elevator host, and the frequency converter is connected with the elevator host provided with the star-sealing contactor; the star-sealing loop detection method comprises the following steps:

in the elevator brake release and speed controllable operation, a flag allowing star-sealing detection is made according to load information of an elevator or current or voltage or power or torque information output by a frequency converter;

when the frequency converter receives the command of stopping output and allowing star sealing detection, the frequency converter performs electronic star sealing to form a follow current path between the frequency converter and the elevator host;

under the condition that the elevator host is in a follow current state based on the follow current path, the elevator control system controls the star sealing contactor to seal a star for the elevator host;

and the elevator control system determines a star sealing loop detection result based on the change of the follow current of the star sealing loop before and after the star sealing action of the star sealing contactor.

2. The star-sealed loop detection method as claimed in claim 1, comprising: detecting the output current of the frequency converter; when the detected current reaches a preset current value, a flag allowing star-sealing detection is made.

3. The star-sealed loop detection method according to claim 1, wherein the star-sealed loop detection result includes a normal detection result and an abnormal detection result;

the normal detection result is judged by adopting the following method: if the follow current meets a preset condition, the elevator control system determines that the star-sealing loop detection result is a normal detection result; the preset condition comprises that the value of the follow current is zeroed along with the star sealing action of the star sealing contactor;

the abnormality detection result is judged by the following method: and if the follow current does not meet the preset condition, the elevator control system determines that the star-sealed loop detection result is an abnormal detection result.

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