Variable-power combined motor for escalator and moving sidewalk and control method

Abstract

The invention discloses a variable-power combined motor for an escalator and a moving sidewalk and a control method, and aims to solve the problem that the overall efficiency of a driving motor is not high due to the fact that the load rate of the driving motor of the escalator and the moving sidewalk is always in a very low state. One high-power alternating-current motor is replaced by a combination of three coaxial or heteroaxial parallel low-power alternating-current motors, one motor is a fine-tuning motor, the rest motors are coarse-tuning motors, the efficiency of driving the motors is improved through a method that the fine-tuning motors enable the coarse-tuning motors to be stably put into operation or quit operation along with the random change of a load, and the efficiency of driving the motors is improved. And the fine adjustment motor always runs in an efficient area, so that the situation that a large motor pulls a small motor is avoided, the conversion efficiency between electric energy and mechanical energy is improved, and the method is simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design and control, and in particular to a variable power AC motor for escalators and moving walkways and a control method thereof. Background Art

[0002] Saving energy, reducing pollution and protecting the environment have become the most pressing issues facing the world's industry and even all mankind. Variable power motors can automatically change the motor power according to the load size to improve the efficiency of the whole machine. Such motors are receiving more and more attention from governments of various countries. Escalators and moving walkways are common public transportation tools in modern cities, but the range of variation in the amount of objects they carry is very random, which makes the load rate of the drive motors of escalators and moving walkways often very low, and thus their efficiency is often very low.

[0003] Chinese patent publication number CN 118473172 A, publication date August 9, 2024, the invention name is a variable rated power combination motor, the invention discloses a method of replacing a high-power motor with several identical low-power motors in parallel, one of which is a fine-tuning motor and the rest are coarse-tuning motors. With the random changes in the load, the coarse-tuning motor is smoothly put into or out of operation through the fine-tuning motor. The disadvantage is that the fine-tuning motor often runs at a very low load rate, which affects the improvement of the overall efficiency of the motor. Summary of the invention

[0004] Technical issues to be solved The technical problem to be solved by the present invention is that when a coarse-adjusting motor is switched on or off, a fine-adjusting motor often operates in a state of very low efficiency.

[0005] Technical Solution In order to solve the above problems, the present invention is implemented through the following technical scheme: a high-power AC motor is replaced by a combination of three low-power AC motors connected in parallel with the same axis or different axes, the total power of the three small motors is the same as the power of one large motor, the high-power AC motor is the mother motor, the low-power AC motor is the sub-motor, the rated power parameters and rated speed of the mother motor and the sub-motor are the same, two of the sub-motors are coarse-adjustment motors, the rated power of coarse-adjustment motor 1 is 1 / 5 of the mother motor, the rated power of coarse-adjustment motor 2 is 2 / 5 of the mother motor, and the third is a fine-adjustment motor, the rated power of the fine-adjustment motor is 2 / 5 of the mother motor; the two coarse-adjustment motors can share a rotating shaft, a housing, a set of bearings, and a cooling system, and the coarse-adjustment motor and the fine-adjustment motor are both three-phase AC asynchronous motors; or the two coarse-adjustment motors are three-phase AC asynchronous motors, and the fine-adjustment motor is a three-phase AC synchronous motor. Automatic escalators and moving walkways usually run at a constant speed and variable torque state. The fine-tuning motor adopts speed negative feedback closed-loop control. During the load increase process, when the output torque of the fine-tuning motor increases to its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to be put into operation, and the output torque of the fine-tuning motor is controlled to be reduced to half of its rated value. During the load reduction process, when the output torque of the fine-tuning motor decreases to half of its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to stop running, and the output torque of the fine-tuning motor is controlled to increase to its rated value; the order of putting the coarse-tuning motor into operation is as follows: When it needs to be put into operation for the first time, coarse adjustment motor 1 is put into operation; when it needs to be put into operation for the second time, coarse adjustment motor 2 is put into operation and coarse adjustment motor 1 is withdrawn; when it needs to be put into operation for the third time, coarse adjustment motor 1 is put into operation. When all coarse adjustment motors are put into operation, the order of withdrawing the coarse adjustment motors is as follows: when it needs to be withdrawn for the first time, coarse adjustment motor 1 is withdrawn; when it needs to be withdrawn for the second time, coarse adjustment motor 2 is withdrawn and coarse adjustment motor 1 is put into operation; when it needs to be withdrawn for the third time, coarse adjustment motor 1 is withdrawn. If all coarse adjustment motors have not been put into operation yet and a coarse adjustment motor needs to be withdrawn again, the corresponding second or third withdrawal method when all are put into operation is directly adopted.

[0006] Beneficial Benefits When the above technical solution is adopted, when the motor load rate is low, the motor load rate can be increased by continuously and smoothly changing the rated power of the combined motor, and the fine-tuning motor also has a higher load rate and efficiency when the coarse-tuning motor is put into or out of operation, thus avoiding the waste of a big horse pulling a small cart. It not only saves energy and reduces emissions, but is also simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a schematic diagram of the internal structure of the mother motor. Figure 2 It is a schematic diagram of the internal structure of a variable power combination motor that uses three sub-motors to replace the main motor.

[0008] Specific implementation like Figure 1 and Figure 2 As shown, one high-power AC motor is replaced by a combination of three low-power AC motors connected in parallel with the same or different axes. The total power of the three small motors is the same as the power of one large motor. The high-power AC motor is the mother motor, and the low-power AC motor is the daughter motor. The rated power parameters and rated speed of the mother motor and the daughter motor are the same. Two of the daughter motors are coarse-adjustment motors, and the rated power of coarse-adjustment motor 1 is 1 / 5 of that of the mother motor, and the rated power of coarse-adjustment motor 2 is 2 / 5 of that of the mother motor. The third is a fine-adjustment motor, and the rated power of the fine-adjustment motor is 2 / 5 of that of the mother motor.

[0009] like Figure 2 As shown, two coarse-adjustment motors can share a rotating shaft, a housing, a set of bearings, and a cooling system. The coarse-adjustment motor and the fine-adjustment motor are both three-phase AC asynchronous motors, or the coarse-adjustment motor is a three-phase AC asynchronous motor, and the fine-adjustment motor is a three-phase AC synchronous motor. The analogy method is used to determine the main dimensions of the three sub-motors. The inner diameter of the sub-motor stator is the same as that of the mother motor. The effective length of the armature of coarse-adjustment motor 1 is 1 / 5 of that of the mother motor, the cross-sectional area of ​​the winding conductor of coarse-adjustment motor 1 is 1 / 5 of that of the mother motor, and the number of turns of the winding of coarse-adjustment motor 1 is 5 times that of the mother motor. The effective length of the armature of coarse-adjustment motor 2 is 2 / 5 of that of the mother motor, the cross-sectional area of ​​the winding conductor of coarse-adjustment motor 2 is 2 / 5 of that of the mother motor, and the number of turns of the winding of coarse-adjustment motor 2 is 5 / 2 times that of the mother motor. There is a gap between the two coarse-adjustment sub-motors in the axial direction, and the size of the gap ensures that the windings do not interfere with each other in space. The effective length of the armature of the fine-adjustment motor is 2 / 5 of that of the mother motor, the cross-sectional area of ​​the winding conductor of the fine-adjustment motor is 2 / 5 of that of the mother motor, and the number of turns of the winding of the fine-adjustment motor is 5 / 2 times that of the mother motor.

[0010] Automatic escalators and moving walkways usually run at constant speed and variable torque. The fine-tuning motor adopts the strategy of AC chopping to realize voltage and speed regulation negative feedback closed-loop control. The duty cycle of the winding voltage AC chopping when the fine-tuning motor output torque is half of its rated value is established offline. α Function of given speed f(٠) ,Right now: α=f(n) (1) During the load increase process, when the output torque of the fine-tuning motor increases to its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to be put into operation. At the same time, the output torque of the fine-tuning motor is controlled to be reduced to half of its rated value based on formula (1). During the load reduction process, when the output torque of the fine-tuning motor is reduced to half of its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to be stopped from operation. At the same time, the output torque of the fine-tuning motor is controlled to be increased to its rated value based on formula (1).

[0011] The order of putting the coarse adjustment motors into operation is as follows: when it is needed for the first time, coarse adjustment motor 1 is put into operation; when it is needed for the second time, coarse adjustment motor 2 is put into operation and coarse adjustment motor 1 is withdrawn; when it is needed for the third time, coarse adjustment motor 1 is put into operation; when all the coarse adjustment motors are put into operation, the order of withdrawing the coarse adjustment motors is as follows: when it is needed for the first time, coarse adjustment motor 1 is withdrawn; when it is needed for the second time, coarse adjustment motor 2 is withdrawn and coarse adjustment motor 1 is put into operation; when it is needed for the third time, coarse adjustment motor 1 is withdrawn; if not all coarse adjustment motors are put into operation yet and another coarse adjustment motor needs to be withdrawn, the corresponding second or third withdrawal method when all are put into operation is directly adopted.

Claims

1. A variable power combination motor is a combination of three coaxial or eccentrically connected low-power AC motors to replace one high-power AC motor. The total power of the three small motors is the same as the power of one large motor. The high-power AC motor is the mother motor and the low-power AC motor is the daughter motor. The mother motor and the daughter motor have the same rated power parameters and rated speed. The characteristics are: Two of the sub-motors are coarse-adjustment motors. The rated power of coarse-adjustment motor 1 is 1 / 5 of that of the main motor, the rated power of coarse-adjustment motor 2 is 2 / 5 of that of the main motor, and the third is a fine-adjustment motor. The rated power of the fine-adjustment motor is 2 / 5 of that of the main motor.

2. A combined motor according to claim 1, characterized in that: The two coarse-adjustment motors share a rotating shaft, a housing, a set of bearings, and a cooling system. The coarse-adjustment motor and the fine-adjustment motor are both three-phase AC asynchronous motors, or the coarse-adjustment motor is a three-phase AC asynchronous motor, and the fine-adjustment motor is a three-phase AC synchronous motor.

3. A constant speed variable torque control method based on the combined motor according to claim 2, characterized in that: The fine-tuning motor adopts speed negative feedback closed-loop control. During the load increase process, when the output torque of the fine-tuning motor increases to its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to be put into operation, and the output torque of the fine-tuning motor is controlled to be reduced to half of its rated value. During the load reduction process, when the output torque of the fine-tuning motor is reduced to half of its rated value, the coarse-tuning motor equivalent to 1 / 5 of the rated power of the mother motor is controlled to stop running, and the output torque of the fine-tuning motor is controlled to increase to its rated value.

4. A control method based on the combined motor according to claim 3, characterized in that: The order of putting the coarse adjustment motors into operation is as follows: when it is needed for the first time, coarse adjustment motor 1 is put into operation; when it is needed for the second time, coarse adjustment motor 2 is put into operation and coarse adjustment motor 1 is withdrawn; when it is needed for the third time, coarse adjustment motor 1 is put into operation; when all the coarse adjustment motors are put into operation, the order of withdrawing the coarse adjustment motors is as follows: when it is needed for the first time, coarse adjustment motor 1 is withdrawn; when it is needed for the second time, coarse adjustment motor 2 is withdrawn and coarse adjustment motor 1 is put into operation; when it is needed for the third time, coarse adjustment motor 1 is withdrawn; if not all coarse adjustment motors are put into operation yet and another coarse adjustment motor needs to be withdrawn, the corresponding second or third withdrawal method when all are put into operation is directly adopted.

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