Elevator system load measurement method

Abstract

An elevator system load-bearing measurement method of the present invention includes: stopping the car by braking; inputting stator coil current into the stator coil to generate a stator magnetic field, the direction of which is the same as the direction of the rotor magnetic field, which is the first direction; releasing the brake to allow the car and counterweight to move due to gravity, the car driving the rotor of the motor by the traction rope to cause the rotor to deflect; the interaction between the rotor magnetic field and the stator magnetic field to generate an induced magnetic field torque, and bringing the rotor to a balance position, where the direction of the rotor magnetic field is the second direction, and the first and second directions form an angle; and calculating the load-bearing capacity of the car based on the angle.

Description

Elevator system load measurement method The invention relates to a load measurement method for an elevator system. When an elevator is in operation, a method is needed to accurately measure the elevator's passenger capacity to determine whether the elevator's load has reached its maximum load limit and whether there is still enough room to accommodate more passengers or cargo. Traditional methods for measuring elevator capacity include installing a rigid material with an appropriate Young's modulus between the elevator car and the elevator traction rope, or between two elevator traction ropes, attaching a resistance strain gauge to the surface of the rigid material, and building the resistance strain gauge into a Huygens bridge circuit. The load of the elevator causes the rigid material to deform, resulting in a change in the resistance of the resistance strain gauge. In the Huygens bridge, the change in resistance of the resistance strain gauge is converted into a change in voltage. Using a microprocessor, the voltage change can be read, processed, and calculated to measure the elevator's load capacity. The present invention provides an elevator system load measurement method for measuring the load weight of an elevator. Some embodiments of the present invention provide a method for measuring the load of an elevator system, wherein the elevator system comprises: a car, the car having a load; a counterweight; a traction rope for connecting the car and the counterweight; a motor, the traction rope being connected to the motor, the motor driving the traction rope when running to move the car and the counterweight, the motor comprising: a stator coil for generating a stator magnetic field; a rotor for generating a rotor magnetic field; and a brake for stopping the motor from rotating. The method comprises: using the brake to stop the car; inputting a stator coil current into the stator coil to stop the stator coil; and The stator coil generates a stator magnetic field, and the direction of the stator magnetic field is the same as the direction of the rotor magnetic field of the rotor. At this time, the direction of the rotor magnetic field is a first direction; the brake is released, so that the carriage and the counterweight block move due to gravity, and the carriage drives the rotor of the motor through the traction rope to deflect the rotor; the rotor magnetic field and the stator magnetic field interact to generate an induced magnetic field torque, and put the rotor in an equilibrium position. At this time, the direction of the rotor magnetic field of the rotor is a second direction, and the first direction and the second direction generate an angle; based on the angle, the load of the carriage is calculated. According to some embodiments of the present invention, the weight of the counterweight is the sum of the empty weight of the carriage and an additional weight. According to some embodiments of the present invention, the additional weight ranges from 40% to 60% of the maximum load-bearing weight of the carriage. According to some embodiments of the present invention, the stator coil is a three-phase coil. According to some embodiments of the present invention, the rotor is a permanent magnet or an electromagnet. According to some embodiments of the present invention, the motor further includes an encoder connected to the rotating shaft of the rotor for measuring the deflection angle of the rotor. According to some embodiments of the present invention, calculating the passenger load of the carriage based on the included angle includes calculating the passenger load of the carriage by using a table lookup method or an interpolation method. Some other embodiments of the present invention provide a load-bearing measurement method for an elevator system, the elevator system comprising: a car, the car having a load; a counterweight; a traction rope for connecting the car and the counterweight; a motor, the traction rope being connected to the motor, the motor driving the traction rope when running to move the car and the counterweight, the motor comprising: a stator coil for generating a stator magnetic field; a rotor for generating a rotor magnetic field; a brake for stopping the motor from rotating, the method comprising: using the brake to stop the car; inputting a first stator coil current into the stator coil so that the stator coil generates a first stator magnetic field, the first stator magnetic field and the rotor magnetic field of the rotor having the same direction, at which time the rotor magnetic field The direction of the field is a first direction; releasing the brake causes the carriage and the counterweight to move due to gravity, and drives the rotor of the motor to deflect the rotor; the rotor magnetic field interacts with the stator magnetic field to generate an induced magnetic field torque, and causes the rotor to be in a first equilibrium position, at which time the direction of the rotor magnetic field of the rotor is a second direction, and the first direction and the second direction generate a first angle; changing the stator coil current causes the rotor to be in a second equilibrium position, at which time the direction of the rotor magnetic field of the rotor is a third direction, and the first direction and the third direction generate a second angle, and at this time the magnitude of the stator coil current is a second stator coil current; based on the second stator coil current, the load of the carriage is calculated. According to some embodiments of the present invention, the weight of the counterweight is the sum of the empty weight of the carriage and an additional weight. According to some embodiments of the present invention, the additional weight ranges from 40% to 60% of the maximum load-bearing weight of the carriage. According to some embodiments of the present invention, the stator coil is a three-phase coil. According to some embodiments of the present invention, the rotor is a permanent magnet. According to some embodiments of the present invention, the motor further includes an encoder connected to the rotating shaft of the rotor for measuring the deflection angle of the rotor. According to some embodiments of the present invention, calculating the passenger load of the carriage based on the second stator coil current includes calculating the passenger load of the carriage by using a table lookup method or an interpolation method. According to some embodiments of the present invention, there is a maximum angle between the direction of the rotor magnetic field of the rotor and the first direction. When the carriage is at maximum load and the angle between the direction of the rotor magnetic field of the rotor and the first direction is the maximum angle, the current input into the stator coil is the first stator coil current, and the magnetic field generated by the stator coil is the first stator magnetic field. According to some embodiments of the present invention, the second angle is the maximum angle. According to some embodiments of the present invention, there is a maximum angle between the direction of the rotor magnetic field of the rotor and the first direction. When the carriage is an empty carriage and the angle between the direction of the rotor magnetic field of the rotor and the first direction is the maximum angle, the current input into the stator coil is the first stator coil current, and the magnetic field generated by the stator coil is the first stator magnetic field. According to some embodiments of the present invention, the second angle is the maximum angle. Based on the above, the present invention uses the angle of motor rotation to determine the weight difference between the elevator and the counterweight. By measuring the direction of motor rotation, it can also be determined whether the elevator weight is greater than, less than, or equal to the counterweight. The elevator's load can thus be determined using this proposed direction. This method provides a safe way to measure an elevator's load. Furthermore, this method utilizes the current and position sensors of the original elevator inverter, allowing safe and reliable measurement of the elevator's load without the need for additional electronic or mechanical measurements or sensors. FIG1 is a schematic diagram of an elevator system according to an embodiment of the present invention. 1 , the elevator system 10 includes a car 20A, a counterweight 20B, a traction rope 24 , and a motor 30 . The carriage 20A has a load. In some embodiments, the load may be people or cargo transported by the carriage 20A. A counterweight 20B is located on the other side of the elevator system 10. A traction rope 24 is provided between the carriage 20A and the counterweight 20B to connect the carriage 20A and the counterweight 20B. The primary function of the counterweight 20B is to form a weight-balancing system with the carriage 20A, ensuring stability and preventing excessive sway during the vertical movement of the carriage 20A. In some embodiments, the weight of the counterweight 20B is the sum of the empty weight of the carriage 20A and an additional weight. In some embodiments, the additional weight ranges from 40% to 60% of the maximum load capacity of the carriage. Therefore, the weight of the counterweight 20B is approximately equal to half the weight of the carriage plus the maximum load capacity. In the elevator system's motor 30, the carriage 20A and counterweight 20B are connected to the motor 30 via a traction rope 24 and a pulley system 22. When the motor 30 is running, the traction rope 24 drives the carriage 20A and counterweight 20B, allowing the carriage 20A to move to a desired location, such as a different floor. In some embodiments, the number and position of the pulley systems 22 can be configured as desired, and the present disclosure is not limited thereto. In some embodiments, the traction rope 24 can be a steel cable or other similar rope, but the present disclosure is not limited thereto. FIG. 2 is a schematic diagram of a motor according to an embodiment of the present invention. 2 , the motor 30 includes a processor 32 , a stator coil 34 , a rotor 36 , a brake 38 , and an encoder 40 . The processor 32 is electrically connected to the stator coil 34, the rotor 36, the brake 38, and the encoder 40. The processor 32 can control the current input to the stator coil 34 and the rotor 36 to control the operation of the rotor 36. The processor 32 can control the activation and deactivation of the brake 38 to inhibit the rotation of the motor 30. The processor 32 can read the value changes of the encoder 40 to monitor the rotation state of the motor 30 shaft, such as the rotation angle. In some embodiments, the processor 32 may be a microcontroller (MCU) or a device with similar functionality. The processor 32 may also have communication capabilities, such as wired or wireless transmission, to transmit acquired data, such as current changes in the stator coil 34 and rotor 36, activation and deactivation of the brake 38, and changes in the encoder 40 value, to an external device. The stator coil 34 and the rotor 36 are the core of the motor 30. The stator coil 34 is used to generate a stator magnetic field. The rotor 36 is used to generate a rotor magnetic field. The motor continues to run through the interaction between the stator magnetic field and the rotor magnetic field. The rotor 36 is connected to the motor shaft (not shown) to drive the motor to rotate. In some embodiments, the stator coil 34 is a three-phase coil, or has a similar function, and the present disclosure is not limited to this. In some embodiments, the rotor 36 is a permanent magnet or an electromagnet, or has a similar function, and the present disclosure is not limited to this. In addition, since the motor shaft is connected to the rotor 36, the rotation of the rotor 36 is equivalent to the rotation of the motor shaft, or the rotation of the motor. Brake 38 is used to stop motor 30 during operation. In some embodiments, brake 38 may be an electromagnetic brake or other similar device, but the present disclosure is not limited thereto. In some embodiments, the number of brakes 38 may be one or more, depending on actual needs, but the present disclosure is not limited thereto. The encoder 40 is connected to the shaft of the rotor 36 and is used to measure the angle of deflection of the rotor 36. In some embodiments, the encoder 40 is a rotary encoder with a resolution of 10 bits to 13 bits, but the present disclosure is not limited to this. For example, a resolution of 10 bits is equivalent to dividing a full circle of 360 degrees into 2 10 =1024 equal parts, that is, the resolution is 360 / 1024=0.35 degrees. If the resolution is 13 bits, it is equivalent to dividing 360 degrees into 2 13 = 8192 equal parts, which means the resolution is 360 / 8192 = 0.044 degrees. Therefore, it can be used to analyze the tiny rotation of the motor shaft. FIG. 3 is a schematic diagram of a stator coil and a rotor of a motor according to an embodiment of the present invention. Please refer to Figure 3. As shown in Figure 3, the stator coil 34 is a three-phase magnet, comprising coils AA', BB, and CC'. Current flows into coils A, B, and C, respectively, and out of coils A', B', and C'. By supplying different currents to coils AA', BB, and CC', the directions of the magnetic fields generated by coils AA', BB, and CC' can be controlled, thereby synthesizing the stator magnetic field of stator coil 34. The rotor 36 is located inside the stator coil 34. As shown in FIG3, the rotor 36 has a north pole and an south pole. The rotor 36 has a coordinate system dq that rotates with the rotor 36 , wherein the d-axis is parallel to the line connecting the rotor's north and south poles, with the north pole located in the +d direction, and the q-axis is perpendicular to the d-axis. FIG. 4 is a schematic diagram of a stator coil and a rotor of a motor according to an embodiment of the present invention. Please refer to Figure 4. Figure 4 is similar to Figure 3, except that when rotor 36 rotates relative to stator coil 34, rotor 36's coordinate system dq does not rotate relative to rotor 36. Rotor 36's coordinate system dq effectively describes the relationship between stator coil 34 and rotor 36. In the following embodiments, a method for measuring load bearing capacity of an elevator system is provided. Figure 5A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 5B is a schematic diagram of the function of the stator coil and the rotor corresponding to Figure 5A. Please refer to Figure 5A and Figure 5B at the same time. Figure 5A is a schematic diagram of the relative relationship between the carriage 20A and the counterweight 20B. In Figure 5A, the weight of the carriage 20A is greater than the weight of the counterweight 20B. 5B . First, the carriage 20A is stopped by the brake 38. Specifically, when the carriage 20A stops at the target floor, the brake 38 is used to lock the carriage 20A so that it is immobile. It is worth noting that when car 20A is parked at the target floor, rotor 36 may be pointing at any angle. Next, the stator coil current I is input to the stator coil 34. f * , causing the stator coil 34 to generate a stator magnetic field with the same direction as the rotor magnetic field of the rotor 36. In this case, the direction of the rotor magnetic field is a first direction. Specifically, by controlling the direction and magnitude of the current in the stator coil 34, a stator magnetic field with the same direction as the magnetic field of the rotor 36 can be generated. Because the stator magnetic field and the rotor magnetic field have the same direction, the force between the stator magnetic field and the rotor magnetic field exists only in the direction along the rotor magnetic field. Therefore, the current I f * The magnetic field can be decoupled into the current I along the q-axis and the d-axis. q and current I d The current I along the q-axis q The rotor 36 can be rotated, and the current I along the d-axis direction d The rotor 36 will not be rotated, but a radial force will be generated. Next, brake 38 is released, causing car 20A and counterweight 20B to move due to gravity. Car 20A drives rotor 36 of motor 30 via traction rope 24, causing rotor 36 to deflect in a clockwise direction. Specifically, because car 20A is heavier than counterweight 20B, car 20A moves downward due to gravity, causing the elevator system's motor to rotate accordingly. Then, the rotor magnetic field interacts with the stator magnetic field to generate an induced magnetic field torque, and places the rotor 36 in an equilibrium position, wherein the magnetic field direction of the rotor 36 is the second direction, which forms an angle θ with the first direction. Specifically, if the rotor 36 rotates clockwise as shown in FIG5A , the rotor 36 is energized by the current I in the first direction. f * The magnetic field direction of the rotor 36 relative to the first direction is also fixed. On the other hand, since the rotor 36 rotates, the magnetic field direction of the rotor 36 relative to the rotor reference axis (q axis and d axis) is also fixed. q and I d The current will change, that is, I q Big and I d becomes smaller. At this time, the current I q The induced magnetic field and the rotor magnetic field generate a torque that causes the rotor 36 to rotate, and this torque is in the same direction as the torque generated by the downward force of the carriage 20A. q The force generated by the induced magnetic field is an upward force, which can counteract the downward force exerted by gravity on the carriage 20A. Therefore, when the two torques are equal in magnitude and direction, the rotor 36 reaches equilibrium and is in an equilibrium position, where the direction of the magnetic field of the rotor 36 forms an angle θ with the first direction. In addition, when the weight of the carriage 20A is heavier, the angle θ of the rotor 36 will be larger, so the current I q The larger the current I d The smaller it is, the greater the steering force will be, and finally the car 20A will reach equilibrium. Here, the rotation angle of the rotor 36 can be measured by the encoder 40 shown in FIG. 2 , and the measurement result is transmitted back to the processor 32 . Next, the elevator's load is calculated based on the angle θ. Specifically, there is a one-to-one correspondence between the weight of car 20A and the angle θ. Therefore, after measuring the angle θ of rotor 36, processor 32 can calculate the load of car 20A, including by using a table lookup or interpolation method, to determine the current weight of the car. Figure 6A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 6B is a schematic diagram of the function of the stator coil and the rotor corresponding to Figure 6A. Please refer to Figure 6A and Figure 6B. Compared with the situation of Figure 5A and Figure 5B, the difference is that the weight of the carriage 20A in Figure 6A and Figure 6B is less than the counterweight 20B. Therefore, when brake 38 is released, car 20A and counterweight 20B move due to gravity. Car 20A drives rotor 36 of motor 30 via traction rope 24, causing rotor 36 to deflect counterclockwise. Specifically, because car 20A weighs less than counterweight 20B, car 20A moves upward due to the downward pull of counterweight 20B, causing the elevator system's motor to rotate accordingly. Therefore, if the rotor 36 rotates counterclockwise as shown in FIG6A , the current I f *The magnetic field direction of the rotor 36 relative to the first direction is also fixed. On the other hand, since the rotor 36 rotates, the magnetic field direction of the rotor 36 relative to the rotor reference axis (q axis and d axis) is also fixed. q and I d The current will change, that is, I q Big and I d becomes smaller. At this time, the current I q The induced magnetic field and the rotor magnetic field generate a torque that causes the rotor 36 to rotate, and this torque is in the same direction as the torque generated by the downward force of the carriage 20A. q The force generated by the induced magnetic field is a downward force, counteracting the upward force exerted on car 20A by the downward pull of counterweight 20B. Therefore, when the two moments are equal in magnitude and direction, rotor 36 reaches equilibrium and is in an equilibrium position, where the direction of the magnetic field of rotor 36 forms an angle θ with the first direction. The elevator's load capacity is calculated based on this angle θ using the aforementioned method. Figure 7A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 7B is a schematic diagram of the function of the stator coil and the rotor corresponding to Figure 7A. Please refer to Figure 7A and Figure 7B. Compared with the situations of Figure 5A and Figure 5B and Figure 6A and Figure 6B, the difference is that the weight of the carriage 20A and the weight of the counterweight 20B are equal in Figure 7A and Figure 7B. Therefore, when the brake 38 is released, the carriage 20A and the counterweight 20B will not move upward or downward due to their equal weight. Therefore, when the angle θ is 0, it can be seen that the weight of the carriage 20A is equal to the weight of the counterweight 20B. Therefore, by measuring the rotor's rotation angle when the brake is released, the weight difference between the elevator and the counterweight can be determined. By measuring the direction of the rotor's rotation, it can also be determined whether the elevator's weight is greater than, less than, or equal to the counterweight. The elevator's load can then be determined using the proposed direction. This method provides a safe way to measure an elevator's load. In the following embodiment, another elevator system load measurement method is provided. Figure 8A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 8B is a schematic diagram of the function of the stator coil and the rotor corresponding to Figure 8A. Please refer to Figure 8A and Figure 8B simultaneously. Figure 5A is a schematic diagram of the relative relationship between the carriage 20A and the counterweight 20B. In Figure 8A, the weight of the carriage 20A is greater than the weight of the counterweight 20B. Please refer to Figure 8B. First, the car 20A is stopped by the brake 38. Specifically, when the car 20A stops at the target floor, the brake 38 is used to lock the car 20A so that it is not moving. Next, the first stator coil current I is input to the stator coil 34. f * , causing the stator coil 34 to generate a first stator magnetic field. The first stator magnetic field is oriented in the same direction as the rotor magnetic field of the rotor 36. In this case, the direction of the rotor magnetic field is the first direction. Specifically, by controlling the direction and magnitude of the current in the stator coil 34, a first stator magnetic field is generated that is oriented in the same direction as the magnetic field of the rotor 36. Because the first stator magnetic field and the rotor magnetic field are oriented in the same direction, the force between the first stator magnetic field and the rotor magnetic field exists only in the direction along the rotor magnetic field. Therefore, the current I f * The magnetic field can be decoupled into the current I along the q-axis and the d-axis. q and current I d The current I along the q-axis q The rotor 36 can be rotated, and the current I along the d-axis direction d The rotor 36 will not be rotated, but a radial force will be generated. In addition, there is a maximum angle between the direction of the rotor magnetic field of the rotor 36 and the first direction. When the carriage 20A is at the maximum load and the angle between the direction of the rotor magnetic field of the rotor 36 and the first direction is at the maximum angle, the current I input to the stator coil 34 at this time d is the first stator coil current, i.e. I d =I f * =I d,max , the magnetic field generated by the stator coil 34 is the first stator magnetic field. Next, brake 38 is released, causing car 20A and counterweight 20B to move due to gravity. Car 20A drives rotor 36 of motor 30 via traction rope 24, causing rotor 36 to deflect in a clockwise direction. Specifically, because car 20A is heavier than counterweight 20B, car 20A moves downward due to gravity, causing the elevator system's motor to rotate accordingly. The rotor magnetic field and the stator magnetic field interact to generate an induced magnetic field torque, and place the rotor 36 in a first equilibrium position, wherein the direction of the rotor magnetic field of the rotor 36 is a second direction, and the second direction forms a first angle with the first direction. Next, change the stator coil current I d , so that the rotor 36 is in a second equilibrium position. At this time, the direction of the rotor magnetic field of the rotor 36 is the third direction, and the first direction and the third direction form a second angle. At this time, the stator coil current I d The magnitude of the second stator coil current I d . Specifically, due to the stator coil current I d =I d,max When the car is at its maximum load, the current at the maximum angle is generated. Therefore, by reducing the stator coil current I d , the carriage 20A can continue to move downward, so that the angle between the direction of the rotor magnetic field of the rotor 36 and the first direction increases from the first angle to a second angle, and the second angle is the maximum angle. At this time, the measured current I d and returns the measured result to the processor 32. Then, according to the current I d , calculate the load of the elevator. Specifically, the weight of the car 20A and the current I d It is a one-to-one correspondence, so after measuring the current I d Thereafter, the processor 32 may calculate the load of the carriage 20A by using a table lookup method or an interpolation method to obtain the current weight of the carriage. Figure 9A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 9B is a schematic diagram of the function of the stator coil and the rotor corresponding to Figure 9A. Please refer to Figure 9A and Figure 9B. Compared with the situation of Figure 8A and Figure 8B, the difference is that the weight of the carriage 20A in Figure 9A and Figure 9B is less than the counterweight 20B. There is a maximum angle between the direction of the rotor magnetic field of the rotor 36 and the first direction. When the carriage 20A is unloaded, that is, the weight of the carriage 20A is minimal, and the angle between the direction of the rotor magnetic field of the rotor 36 and the first direction is the maximum angle, the current I input to the stator coil 34 is d is the first stator coil current, i.e. I d =I f * =I d,max , the magnetic field generated by the stator coil 34 is the first stator magnetic field. Therefore, when brake 38 is released, car 20A and counterweight 20B move due to gravity. Car 20A drives rotor 36 of motor 30 via traction rope 24, causing rotor 36 to deflect counterclockwise. Specifically, because car 20A weighs less than counterweight 20B, car 20A moves upward due to the downward pull of counterweight 20B, causing the elevator system's motor to rotate accordingly. The rotor magnetic field and the stator magnetic field interact to generate an induced magnetic field torque, and place the rotor 36 in a first equilibrium position, wherein the direction of the rotor magnetic field of the rotor 36 is a second direction, and the second direction forms a first angle with the first direction. Next, change the stator coil current I d , so that the rotor 36 is in a second equilibrium position. At this time, the direction of the rotor magnetic field of the rotor 36 is the third direction, and the first direction and the third direction form a second angle. At this time, the stator coil current I d The magnitude of the second stator coil current I d . Specifically, due to the stator coil current I d =I d,max When the car is at its minimum load, the maximum angle current is generated, so by reducing the stator coil current I d , the carriage 20A can continue to move upward, so that the angle between the direction of the rotor magnetic field of the rotor 36 and the first direction increases from the first angle to a second angle, and the second angle is the maximum angle. At this time, the measured current I d and returns the measured result to the processor 32. Then, according to the current I d , calculate the load of the elevator. Specifically, the weight of the car 20A and the current I d It is a one-to-one correspondence, so after measuring the current I d Thereafter, the processor 32 may calculate the load of the carriage 20A by using a table lookup method or an interpolation method to obtain the current weight of the carriage. Please refer to Figures 10A and 10B . Compared with the situations of Figures 8A and 8B and Figures 9A and 9B , the difference is that the weight of the carriage 20A and the weight of the counterweight 20B are equal in Figures 10A and 10B . Therefore, when the brake 38 is released, the carriage 20A and the counterweight 20B will not move upward or downward due to their equal weight. Therefore, when the angle θ is 0, it can be seen that the weight of the carriage 20A is equal to the weight of the counterweight 20B. Therefore, by changing the stator motor current when the brake is released, the motor can be turned at a large angle. By measuring the stator motor current at this time, the weight difference between the elevator and the counterweight can be determined. By measuring the direction of motor rotation, it is also possible to determine whether the elevator weight is greater than, less than, or equal to the counterweight. The elevator's load can then be determined using the indicated direction. This method provides a safe way to measure an elevator's load. In summary, the present invention is described with reference to Figures 7A and 7B , which differ from Figures 5A and 5B and Figures 6A and 6B in that the weight of the carriage 20A and the weight of the counterweight 20B are equal in Figures 7A and 7B . Therefore, when the brake 38 is released, the carriage 20A and the counterweight 20B will not move upward or downward due to their equal weight. Therefore, when the angle θ is 0, it can be seen that the weight of the carriage 20A is equal to the weight of the counterweight 20B. Therefore, the present invention uses the angle of motor rotation to determine the weight difference between the elevator and the counterweight. By measuring the direction of motor rotation, it can also be determined whether the elevator weight is greater than, less than, or equal to the counterweight. The elevator's load can thus be determined using the proposed direction. This method provides a safe way to measure the elevator's load. Furthermore, this method utilizes the current and position sensors of the original elevator inverter, allowing safe and reliable measurement of the elevator's load without the need for additional electronic or mechanical measurements or sensors. 10: Elevator system 20A: Car 20B: Counterweight 22: Pulley 24: Traction rope 30: Motor 32: Processor 34: Stator coil 36: Rotor 38: Brake 40: Encoder AA', BB', CC': Coils N, S: Magnetic poles d, q, X, Y: Direction I d , I f * , I q :Currentθ:Angle Figure 1 is a schematic diagram of an elevator system according to an embodiment of the present invention. Figure 2 is a schematic diagram of a motor according to an embodiment of the present invention. Figure 3 is a schematic diagram of the stator coil and rotor of a motor according to an embodiment of the present invention. Figure 4 is a schematic diagram of the stator coil and rotor of a motor according to an embodiment of the present invention. Figure 5A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 5B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 5A. Figure 6A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 6B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 6A. Figure 7A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 7B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 7A. Figure 8A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 8B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 8A. Figure 9A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 9B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 9A. Figure 10A is a schematic diagram of the load of an elevator system according to an embodiment of the present invention. Figure 10B is a schematic diagram of the stator coil and rotor functions corresponding to Figure 10A. 34: stator coil 36: Rotor AA', BB', CC': coil N, S: magnetic poles X, Y: direction I d , I f * , I q :Current θ: angle

Claims

1. A method for measuring the load capacity of an elevator system, the elevator system comprising: A carriage, the carriage having a load-bearing capacity; One counterweight; A traction rope is used to connect the carriage to the counterweight; A motor is provided, connected to a traction rope. When the motor operates, it drives the traction rope, causing the carriage and the counterweight to move. The motor includes: a stator coil for generating a stator magnetic field; a rotor for generating a rotor magnetic field; and a brake for stopping the motor. The method includes: stopping the carriage with the brake; inputting a stator coil current to the stator coil to generate a stator magnetic field, the direction of which is the same as the direction of the rotor magnetic field, which is a first direction; releasing the brake, causing the carriage and the counterweight to move due to gravity, the carriage driving the rotor of the motor via the traction rope to deflect the rotor; the rotor magnetic field interacting with the stator magnetic field to generate an induced magnetic field torque, bringing the rotor to a balance position, where the direction of the rotor magnetic field is a second direction, and the first and second directions form an angle; and calculating the load-bearing capacity of the carriage based on the angle.

2. The method as described in claim 1, wherein the weight of the counterweight is the sum of the empty weight of the carriage and an additional weight.

3. The method as described in claim 2, wherein the range of the additional weight is between 40% and 60% of the maximum load capacity of the carriage.

4. The method as described in claim 1, wherein the stator coil is a three-phase coil.

5. The method as claimed in claim 1, wherein the rotor is a permanent magnet or an electromagnet.

6. The method of claim 1, wherein the motor further includes an encoder connected to the shaft of the rotor for measuring the angle of deflection of the rotor.

7. The method of claim 1, wherein calculating the load of the carriage based on the included angle includes calculating the load of the carriage by means of a lookup table or interpolation.

8. A method for measuring the load-bearing capacity of an elevator system, wherein the elevator system comprises: A carriage, the carriage having a load-bearing capacity; One counterweight; A traction rope is used to connect the carriage to the counterweight; A motor is provided, and a traction rope is connected to the motor. When the motor operates, it drives the traction rope, causing the carriage and the counterweight to move. The motor includes: a stator coil for generating a stator magnetic field; a rotor for generating a rotor magnetic field; and a brake for stopping the motor. The method includes: stopping the carriage with the brake; inputting a first stator coil current to the stator coil to generate a first stator magnetic field, the first stator magnetic field being in the same direction as the rotor magnetic field of the rotor, at which point the direction of the rotor magnetic field is a first direction; releasing the brake, causing the carriage and the counterweight to move due to gravity, and driving the rotor of the motor to deflect; the rotor magnetic field interacts with the stator magnetic field to generate an induced magnetic field torque, and puts the rotor in a first equilibrium position, at which point the direction of the rotor magnetic field of the rotor is a second direction, and the first direction and the second direction form a first angle. The stator coil current is changed to bring the rotor to a second equilibrium position. At this time, the direction of the rotor magnetic field is a third direction, and the first direction and the third direction form a second angle. The magnitude of the stator coil current is the second stator coil current. The load of the carriage is calculated based on the second stator coil current.

9. The method as described in claim 8, wherein the weight of the counterweight is the sum of the empty weight of the carriage and an additional weight.

10. The method as described in claim 9, wherein the additional weight ranges from 40% to 60% of the maximum load capacity of the carriage.

11. The method as described in claim 8, wherein the stator coil is a three-phase coil.

12. The method as described in claim 8, wherein the rotor is a permanent magnet.

13. The method of claim 8, wherein the motor further includes an encoder connected to the shaft of the rotor for measuring the angle of deflection of the rotor.

14. The method of claim 8, wherein calculating the load of the car based on the second stator coil current includes calculating the load of the car by a lookup table or an interpolation method.

15. The method as described in claim 8, wherein there is a maximum angle between the direction of the rotor magnetic field of the rotor and the first direction, and when the carriage is under maximum load, and the angle between the direction of the rotor magnetic field of the rotor and the first direction is the maximum angle, the current input to the stator coil is the first stator coil current, and the magnetic field generated by the stator coil is the first stator magnetic field.

16. The method as described in claim 15, wherein the second included angle is the maximum included angle.

17. The method of claim 8, wherein there is a maximum angle between the direction of the rotor magnetic field of the rotor and the first direction, when the carriage is empty and the angle between the direction of the rotor magnetic field of the rotor and the first direction is the maximum angle, the current input to the stator coil is the first stator coil current, and the magnetic field generated by the stator coil is the first stator magnetic field.

18. The method as described in claim 17, wherein the second included angle is the maximum included angle.

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