CN110467072B

CN110467072B - Starting torque compensation method for elevator system and elevator system

Info

Publication number: CN110467072B
Application number: CN201810453185.XA
Authority: CN
Inventors: 钱敏; 刘玉兵
Original assignee: Shanghai Mitsubishi Elevator Co Ltd
Current assignee: Shanghai Mitsubishi Elevator Co Ltd
Priority date: 2018-05-11
Filing date: 2018-05-11
Publication date: 2022-04-12
Anticipated expiration: 2038-05-11
Also published as: CN110467072A

Abstract

The invention discloses a starting torque compensation method for an elevator system. The starting torque compensation method for the elevator system reduces the calculation period of torque compensation, simultaneously keeps the stability of torque control, and simultaneously meets the requirement of accurate calculation. The invention also relates to an elevator system.

Description

Starting torque compensation method for elevator system and elevator system

Technical Field

The invention relates to the field of elevators, in particular to a starting torque compensation method for an elevator system. The invention also relates to an elevator system.

Background

When the elevator is started, in order to make passengers in the elevator car feel comfortable, proper starting torque must be applied to keep the mechanical system of the elevator balanced. Typically, the elevator control system obtains information from the weight sensor and calculates the required starting torque. However, the starting torque value requires additional compensation in the following cases:

in the first case, the output information of the weight sensor is deviated, resulting in deviation of the calculation result of the starting torque.

In case two, some elevators do not have a weight sensor but only a switch-type sensor for a specific load (e.g., an overload value) in the car in order to reduce the cost or simplify the workload of installing, debugging and maintaining the elevator; the elevator control system is then unable to accurately calculate the required starting torque.

Therefore, it is necessary to design a special calculation method for the compensation value of the starting torque.

Patent application No. CN201611023843.9 (temporarily unpublished) discloses a method for calculating a compensation value of a starting torque. The method utilizes the sign information of the speed feedback value to quickly calculate the moment compensation value; and the deviation between the calculated moment compensation value and the actually required moment compensation value is exponentially attenuated by taking 0.5 as a base number at slowest. Although the method of the patent can quickly and accurately calculate the torque compensation value, the following two problems exist:

problem one, additional constraints are imposed on the torque compensation calculation period Ts and the control bandwidth Td of the torque controller.

Specifically, the patent requires Ts ≧ Td; this leads to at least one of the following:

as a result, the moment compensation calculation period cannot reach the minimum;

as a result, the control bandwidth of the torque controller must be large;

the first result, that is, the iteration period of the moment compensation calculation cannot reach the minimum, may cause the calculation speed of the moment compensation to be limited; that is, although the torque compensation value close to the required value can be obtained with a small number of calculation cycles, the calculation cycle itself is large. The second result is that the control bandwidth of the torque controller must be large, which results in the stability of the torque control being affected and thus the noise and vibration index of the elevator actuator being poor.

Second, in the first active calculation cycle of the torque compensation value, the wrong sign may be calculated for the compensation value (i.e. the torque compensation value is approaching in the wrong direction).

Wherein, the effective calculation means updating the moment compensation value according to the sign of the speed feedback value. The situation of said symbol error occurs because at the moment of starting the elevator operation, the elevator actuator may shake very slightly, and the direction of shaking is bidirectional; by "extremely small" it is meant that the amplitude of such jitter is so small that it is generally not detectable by the speed feedback detection mechanism. However, the speed feedback detection mechanism may be in a critical state where the output value is about to change; in this case, too, the "extremely small" jitter causes the response of the feedback speed signal. Although the probability is very low, it does likely occur.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a starting torque compensation method for an elevator system, which reduces a calculation period of torque compensation and simultaneously achieves a requirement of accurate calculation while maintaining stability of torque control.

In order to solve the technical problem, the invention provides a starting torque compensation method for an elevator system, which comprises the following steps: step one, defining a variable DI; and step two, assigning the following variables as: CI is 0; DI ratedI constD; wherein CI is the output quantity of the starting torque compensator, rateDI is the torque value required for maintaining stress balance when a rated load is placed in the car, and constD is the percentage of the maximum possible deviation of the weight sensor in the rateDI; step three, if the elevator is in a stop state, executing step two; otherwise, executing the step four; step four, if VF is equal to 0, executing step three; otherwise, executing the step five; VF provides current running speed feedback information of the elevator for the actuating mechanism to the starting torque compensator by using a pulse type encoder; step five, executing validity test; if the validity test result is failed, executing a third step; otherwise, executing the step six; step six, if the result of multiplying VF by CI is less than or equal to 0, executing step eight; otherwise, executing step seven; step seven, executing a torque test; if the torque test result is failed, executing a step three; otherwise, executing step eight; step eight, if VF is larger than 0, executing the operation: DI is DI/2; CI-DI; otherwise, performing the operation: DI is DI/2; CI is CI + DI;

the effectiveness test method comprises the following steps: if VF (variable frequency) is not equal to 0 is detected for the first time from the operation of the elevator at this time, the test result is failed; otherwise, if the VF is not equal to 0 for the second time, the test result is failed if the sign of the VF is opposite to the sign of the VF not equal to 0 for the first time; if the symbol of the VF at the time is the same as the symbol of the VF which is not equal to 0 for the first time, the test result is passed; otherwise, if the nth detection result shows that VF is not equal to 0, the test result is pass.

The method for testing the torque comprises the following steps: reading a q-axis moment feedback value and assigning the q-axis moment feedback value to a variable IQ; if IQ is greater than (IQS + CI-OFSI) and IQ is less than (IQS + CI + OFSI), the test result is a pass; otherwise, the test result is failed; wherein the OFSI is a constant greater than or equal to 0.

Preferably, the value of the OFSI should satisfy two conditions:

condition one, when the IQ value crosses the (IQs + CI) value, it is ensured that the two can be determined to be approximately equal, without a missed determination;

and secondly, when IQ and IQS + CI are judged to be approximately equal, the deviation between IQ and IQS + CI cannot be too large, so that the accuracy of calculation of the torque compensation value is ensured.

Preferably, in the second condition, an upper value limit is selected for the OFSI through an experiment, and the upper value limit is applicable to all elevators in the same specification.

The invention also discloses an elevator system, which comprises a main controller, a speed controller, a starting torque compensator, a torque controller and an actuating mechanism, wherein the starting torque compensator is used for executing a starting torque compensation method; after the output quantity of the speed controller is added with the output quantity of the starting torque compensator, the sum is used as a torque command to be provided to the torque controller; the actuating mechanism receives the torque generated by the torque controller so that the elevator tracks a speed command; the actuating mechanism also provides feedback information of the current running speed of the elevator to the starting torque compensator by using a pulse type encoder.

Preferably, the speed controller issues a torque command IQS to follow the speed command from the main controller based on the elevator speed feedback signal VF, the speed command, and the weight sensor feedback signal.

Preferably, the starting torque compensator receives an elevator speed feedback signal VF from the actuator and a command from the main controller, and calculates a torque compensation command value CI; the torque compensator is activated to perform the calculation with a period Ts.

The technical effects of the invention comprise:

first, the torque compensation value can be calculated quickly and accurately.

Under the slowest condition, the deviation between the torque compensation value calculated by the method and the actually required value takes 0.5 as a base and is exponentially attenuated. When the actually required torque compensation value is a certain specific value, the method only needs a plurality of calculation cycles to output the required torque compensation value, for example: when the actually required torque compensation value is equal to +/-0.5 rate I constD, the required torque compensation value can be output only by two calculation cycles at the fastest speed; when the actual required torque compensation value is equal to ± 0.25 × ratedjconstd or ± 0.75 × ratedjconstd, only three calculation cycles are required at the fastest, and the required torque compensation value can be output. Even in the slowest case, the deviation between the calculated torque compensation value and the actually required value can be attenuated to be very small with fewer calculation cycles; considering the resistance of the elevator actuating mechanism, even if a certain deviation exists between the calculated moment compensation value and the actually required value, the elevator actuating mechanism still can keep stress balance.

Second, there is no additional constraint on the torque compensation calculation cycle and the control bandwidth of the torque controller.

Since the sign of the result of multiplying VF by CI is determined in step six and the torque test is performed in step seven, the method can ensure that the calculated value of the compensation torque is corrected in the correct direction in each valid calculation period (except the first one) without applying additional constraints on the calculation period of the torque compensation and the control bandwidth of the torque controller.

Third, the correct direction of correction can be achieved during each calculation cycle of torque compensation (i.e., the calculated value of torque compensation always approaches in the correct direction).

Since the validity test is performed in step five, the method can ensure that the calculated value of the compensation moment is corrected to the correct direction in the first valid calculation period. As a cost, the first detected non-zero velocity feedback information is discarded. However, since the calculated value of torque compensation approaches the desired value very quickly, the calculated value of torque compensation can be calculated quickly enough even if one available computer is discarded.

Drawings

Fig. 1 is a block diagram of an elevator system in a starting torque compensation method for an elevator system of the present invention.

Fig. 2 is a flowchart of a calculation of a starting torque compensation value in the starting torque compensation method for an elevator system according to the present invention.

Detailed Description

The invention is described in further detail below with reference to the following figures and detailed description:

an elevator system used in the present invention will be described first with reference to fig. 1.

The main controller is responsible for issuing the following commands:

elevator run/stop commands;

an elevator speed command;

the speed controller sends out a torque instruction IQS according to an elevator speed feedback signal VF, a speed instruction and a weight sensor feedback signal (if the elevator speed feedback signal VF, the speed instruction and the weight sensor feedback signal exist) so as to follow a speed instruction from the main controller;

the starting torque compensator receives an elevator speed feedback signal VF from an actuating mechanism and an elevator running/stopping command from the main controller, and calculates a torque compensation command value CI; the torque compensator is activated to perform the calculation with a period Ts.

The torque controller receives the sum of CI and IQS as a torque command and outputs voltage to the actuating mechanism so as to follow the torque command; the moment controller follows the moment instruction with a certain delay Td; the wider the bandwidth of the torque controller, the smaller the Td; the narrower the bandwidth of the torque controller, the greater Td.

The actuator comprises components such as a traction machine, an elevator mechanical system, a sensor and the like (not shown in detail in the figure):

the traction machine generates torque according to the voltage applied by the torque controller so as to drive the elevator mechanical system;

the elevator mechanical system comprises a conducting component, a car, a counterweight and the like;

the sensor includes:

a pulse type encoder: detecting the speed VF of the elevator, and using the speed controller and the starting torque compensator;

a weight sensor: detecting an unbalanced load of an elevator mechanical system for use by a speed controller; the weight sensor is not necessarily provided, and some elevators do not have a weight sensor.

Example 1

Hereinafter, a preferred embodiment of the present invention will be described with reference to fig. 2. This embodiment is applicable to an elevator without a weight sensor.

Designing and calculating a moment compensation value to be CI; the following steps are carried out:

step one, a variable DI is defined.

And step two, assigning the following variables as:

CI＝0；

DI＝ratedI；

wherein, rateDI is the torque value required for maintaining stress balance when a rated load is placed in the car;

step three, if the elevator is in a stop state, executing step two;

otherwise, executing step four.

Step four, if VF is equal to 0, executing step five;

otherwise, executing step three.

Step five, executing validity test;

if the validity test result is failed, executing a third step;

otherwise, executing step six.

Step six, if the result of multiplying VF by CI is less than or equal to 0, executing step eight;

otherwise, executing step seven.

Step seven, executing a torque test;

if the torque test result is failed, executing a step three;

otherwise, step eight is executed.

Step eight, if VF is larger than 0, executing the operation:

DI＝DI/2；

CI＝CI-DI；

otherwise, performing the operation:

DI＝DI/2；

CI＝CI+DI；

and step nine, executing step three.

In the fifth step, the method for testing the effectiveness comprises the following steps:

if VF not equal to 0 is detected for the first time from the operation of the elevator at this time, the test result is as follows: failing to pass;

otherwise, if VF is not equal to 0 for the second time, if the sign of VF is opposite to the sign of VF when VF is not equal to 0 for the first time, the test result is: failing to pass; if the sign of the VF is the same as the sign of the VF first not equal to 0, the test result is: passing;

otherwise, if the nth detection result is that VF is not equal to 0(N > 2), the test result is: and (4) passing.

In the seventh step, the method of the torque test is as follows:

reading a q-axis moment feedback value and assigning the q-axis moment feedback value to a variable IQ;

if IQ is greater than (IQS + CI-OFSI) and IQ is less than (IQS + CI + OFSI), then the test results are: passing;

otherwise, the test result is: failing to pass.

Wherein the OFSI is a constant of not less than 0.

Hereinafter, a method of selecting the constant OFSI will be described.

The purpose of the "torque test" is to determine whether IQ is approximately equal to IQS + CI. In the ideal case, it should be decided whether IQ is strictly equal to IQS + CI; however, in engineering practice, it is not practical to make a "strictly equal" determination on the feedback value. Therefore, a "substantially equal" decision criterion should be used for the decision of equality between the variables. The "approximately equal" means that the judgment target value is shifted up and down by a certain value to form a judgment target section; if the determined value is within the determination target interval, the two are considered to be approximately equal. Obviously, the constant OFSI is used to construct the "target interval". When IQ and IQS + CI are determined to be approximately equal, OFSI represents the maximum possible deviation between the two. The value of the OFSI should satisfy two conditions:

condition one, when the IQ value crosses the (IQs + CI) value from a certain direction (becoming larger or smaller), it is ensured that both can be determined to be approximately equal without occurrence of a miss.

For the first condition, the value lower limit of the OFSI can be calculated according to the maximum change rate of the IQ and the calculation period of the moment test. The calculation should be able to be done by an engineer in the elevator field; and is not further developed here.

For the second condition, an upper value limit can be selected for the OFSI through experiments. The value upper limit can be applied to all elevators in the same specification, and the value upper limit does not need to be adjusted for each elevator again.

Between said lower value limit and said upper value limit, a suitable value can be selected according to the preference between the rapidity and the error of the moment compensation calculation. The smaller the value of OFSI is, the slower the speed of moment compensation calculation is, and the smaller the error is; and vice versa.

Example 2

The embodiment is applicable to elevators with deviated weight sensors.

step one, a variable DI is defined.

And step two, assigning the following variables as:

CI＝0；

DI＝ratedI*constD；

wherein, rateDI is the torque value required for maintaining stress balance when a rated load is placed in the car; constD is the maximum possible deviation of the weight sensor as a percentage of ratedI.

Step three, if the elevator is in a stop state, executing step two;

otherwise, executing step four.

Step four, if VF is equal to 0, executing step five;

otherwise, executing step three.

Step five, executing validity test;

if the validity test result is failed, executing a third step;

otherwise, executing step six.

otherwise, executing step seven.

Step seven, executing a torque test;

if the torque test result is failed, executing a step three;

otherwise, step eight is executed.

Step eight, if VF is larger than 0, executing the operation:

DI＝DI/2；

CI＝CI-DI；

otherwise, performing the operation:

DI＝DI/2；

CI＝CI+DI；

and step nine, executing step three.

In the seventh step, the method of the torque test is as follows:

otherwise, the test result is: failing to pass.

Wherein the OFSI is a constant of not less than 0.

The CI calculated by the embodiment can quickly and accurately compensate the deviation of the weight sensor.

Claims

1. A starting torque compensation method for an elevator system, comprising the steps of:

step one, defining a variable DI;

and step two, assigning the following variables as: CI is 0; DI ratedI constD; wherein CI is the output quantity of the starting torque compensator, rateDI is the torque value required for maintaining stress balance when a rated load is placed in the car, and constD is the percentage of the maximum possible deviation of the weight sensor in the rateDI;

step three, if the elevator is in a stop state, executing step two; otherwise, executing the step four;

step four, if VF is equal to 0, executing step three; otherwise, executing the step five; VF provides current running speed feedback information of the elevator for the actuating mechanism to the starting torque compensator by using a pulse type encoder;

step five, executing validity test; if the validity test result is failed, executing a third step; otherwise, executing the step six; the effectiveness test method comprises the following steps: if VF (variable frequency) is not equal to 0 is detected for the first time from the operation of the elevator at this time, the test result is failed; if the VF is not equal to 0 detected for the second time, if the sign of the VF at the time is opposite to the sign of the VF which is not equal to 0 for the first time, the test result is failed; if the symbol of the VF at the time is the same as the symbol of the VF which is not equal to 0 for the first time, the test result is passed;

step six, if the result of multiplying VF by CI is less than or equal to 0, executing step eight; otherwise, executing step seven;

step seven, executing a torque test; if the torque test result is failed, executing a step three; otherwise, executing step eight; the method for testing the torque comprises the following steps: reading a q-axis moment feedback value and assigning the q-axis moment feedback value to a variable IQ; if IQ is greater than (IQS + CI-OFSI) and IQ is less than (IQS + CI + OFSI), the test result is a pass; otherwise, the test result is failed; wherein OFSI is a constant greater than or equal to 0, and IQS is a torque command;

step eight, if VF is larger than 0, executing the operation: DI is DI/2; CI-DI; otherwise, performing the operation: DI is DI/2; CI ═ CI + DI.

2. The startup torque compensation method for an elevator system according to claim 1, wherein the OFSI value should satisfy two conditions:

3. The startup torque compensation method for an elevator system according to claim 2, characterized in that in the second condition, an upper value limit is selected for the OFSI through experiments, the upper value limit being applicable to all elevators of the same specification.

4. An elevator system, characterized in that the elevator system comprises a speed controller, a starting torque compensator, a torque controller, an actuator, the starting torque compensator being adapted to perform the starting torque compensation method of one of the claims 1-3; after the output quantity of the speed controller is added with the output quantity of the starting torque compensator, the sum is used as a torque command to be provided to the torque controller; the actuating mechanism receives the torque generated by the torque controller so that the elevator tracks a speed command; the actuating mechanism also provides feedback information of the current running speed of the elevator to the starting torque compensator by using a pulse type encoder.

5. Elevator system according to claim 4, characterized in that the speed controller issues a torque command IQS and follows the speed command from the main controller on the basis of the elevator speed feedback signal VF, the speed command and the weight sensor feedback signal.

6. Elevator system according to claim 5, characterized in that the starting torque compensator receives the elevator speed feedback signal VF from the actuator and calculates the torque compensation command value CI, the starting torque compensator performing the calculation with the period Ts.