Non-intrusive elevator load detection device and elevator applying same

Abstract

The invention relates to the fields of industrial automatic control system device manufacturing, AI + building and the like in the high-end equipment manufacturing industry, in particular to a non-intrusive elevator load detection device and an elevator applying the non-intrusive elevator load detection device. The non-intrusive elevator load detection device comprises a voltage phase induction structure and a mutual inductor which are arranged on the periphery of an A-phase power line of a motor; the transmitter obtains a voltage phase induction signal and a current induction signal; the arithmetic unit is used for executing the following logics: obtaining the no-load current intensity of the A-phase power line in the no-load downlink / uplink state; the no-load phase difference of the current lagging voltage of the A-phase power line in the no-load downlink / uplink state is obtained; in the current load state, the current current intensity of the A-phase power line is obtained; in the current load state, obtaining the current phase difference of the current lagging voltage of the A-phase power line; and calculating the current load of the elevator car. A control system does not need to be changed, and popularization and application are better facilitated.

Description

Technical Field

[0001] This invention relates to the manufacturing of industrial automatic control system devices, intelligent basic general equipment, AI+building and other fields in the high-end equipment manufacturing industry, and particularly to a non-intrusive elevator load detection device and an elevator using it. Background Technology

[0002] According to relevant elevator regulations, when the elevator control system is changed, a relatively complex procedure is required to determine whether the change will affect safety. Calculating active power and collecting voltage, current, and phase difference data are all indispensable. However, most commonly used voltage detection methods require connection to the control system, which will lead to changes in the control system.

[0003] There are some non-invasive voltage detection methods available, but the accuracy is severely affected by factors such as interference, materials, temperature, and humidity. Such power detection accuracy is insufficient to meet the requirements of elevator load detection. Summary of the Invention

[0004] I. Technical problems to be solved

[0005] The present invention aims to at least partially solve one of the above-mentioned technical problems.

[0006] II. Technical Solution

[0007] The first aspect of this invention provides a non-intrusive elevator load detection device. This non-intrusive elevator load detection device includes:

[0008] A voltage phase sensing structure is installed around the A-phase power line of the motor, wherein the A-phase power line is any one of the three-phase power lines of the motor.

[0009] The current transformer is installed around the A-phase power line of the motor;

[0010] The transmitter, connected to the voltage phase sensing structure and the current transformer, is used to condition the received voltage phase sensing structure signal and current transformer signal to obtain voltage phase sensing signal and current sensing signal respectively.

[0011] The arithmetic unit is used to execute the following logic:

[0012] Step A: Obtain the current intensity of phase A power line under no-load down-flow conditions - no-load down-flow current intensity I AD0 ;

[0013] Step B, obtain the current intensity of phase A power line under no-load upward state - no-load upward current intensity I AU0 ;

[0014] Step C, obtain the phase difference of the current lagging voltage of phase A power line under no-load downward state - the phase difference Δφ under no-load downward state. D0 ;

[0015] Step D: Obtain the phase difference between the voltage lag current of phase A power line under no-load upward state and the no-load upward phase difference Δ. φU0 ;

[0016] Step E: Under the current load condition, obtain the current intensity of phase A power line - current current intensity I through the current sensing signal. Ax ;

[0017] Step F: Under the current load condition, obtain the phase difference between the current lag voltage and the current phase difference Δ of the A-phase power line through the current sensing signal and the voltage phase sensing signal. φx ;

[0018] Step G, utilizing the no-load downstream current intensity I of phase A power line AD0 No-load upward current intensity I AU0 ; No-load downlink phase difference Δ φD0 No-load uplink phase difference Δ φU0 Current current intensity I Ax Current phase difference Δ φx The current load on the elevator car is calculated by combining the inverter output voltage or power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator rated speed, and the elevator balance coefficient k.

[0019] In some embodiments of the present invention, the energy form in the A-phase power line is a pulse width modulation wave or a sine wave; both the voltage phase sensing signal and the current sensing signal are pulse width modulation signals or sine wave signals with the same modulation frequency as the pulse width modulation wave, but their phases are different; in steps C, D, and F of the logic executed by the arithmetic unit: the moment when the voltage phase sensing signal changes from negative voltage to positive voltage is defined as the 0° phase of the voltage; the moment when the current sensing signal changes from negative voltage to positive voltage is defined as the 0° phase of the current; the voltage signal delay T of the current sensor and transmitter for the current sensing signal is defined as... AY Define the current signal delay T of the voltage phase sensing signal from the voltage sensor and transmitter. VY ;

[0020] In step C, the no-load downlink phase difference Δ φD0 :

[0021] In step D, the no-load uplink phase difference Δ φU0 :

[0022] In step F, the current phase difference Δ φx :

[0023] Where T is the AC cycle of the pulse width modulation wave or sine wave in phase A power line, and Δ tD0 Δ is the lag time of the current relative to the voltage in the A-phase power line under no-load downward conditions. tU0 Δ is the lag time of the voltage relative to the current in phase A power line under no-load upward conditions. tx This represents the lag time of the current relative to the voltage in the A-phase power line under the current load condition.

[0024] In some embodiments of the present invention, step G in the logic executed by the arithmetic unit includes:

[0025] Sub-step G1, based on the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f, and the no-load downward current intensity I. AD0 Calculate the inductance L of the motor windings;

[0026] Sub-step G2: Calculate the motor active power under no-load downward operation condition - no-load downward active power P kD0 Utilizing the no-load downlink active power P kD0 Calculate the unloaded download power factor Q kD ;

[0027] Sub-step G3: Calculate the motor active power under no-load upward operation condition - no-load upward active power P kU0 Utilizing the no-load uplink active power P kU0 Calculate the unloaded uplink load power factor Q kU ;

[0028] Sub-step G4, using the current phase difference Δ φx Current current intensity I Ax The inductance L of the motor winding is selected using the no-load downstream load power factor Q. kD Or the no-load uplink load power factor Q kU Calculate the current load on the elevator car by taking the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator rated speed, and the elevator balance coefficient k.

[0029] In some embodiments of the present invention, in sub-step G1, the inductance L of the motor winding is:

[0030] In some embodiments of the present invention, Q is the rated load of the elevator, k is the elevator balance coefficient, and in sub-step G2, the active power P during unloaded downward movement is... kD0 for: No-load download power factor Q kD for: In sub-step G3, the no-load uplink active power P kU0 for: No-load uplink load power factor Q kU for:

[0031] In some embodiments of the present invention, in sub-step G4, under the current load state,

[0032] When 0° < Δ φx When the angle is ≤90°, the active power of the motor is: P kx =L2πf(I AD0 ·I Ax cos(Δ φx The current load on the elevator car is: or,

[0033] When 90° < Δ φx When the angle is less than 180°, the active power of the motor is: P kx =L2πf(I AU0 ·I Ax cos(180-Δ) φx The current load on the elevator car is:

[0034] In some embodiments of the present invention, the voltage phase sensing structure is a metal sheet surrounding the A-phase power line.

[0035] In some embodiments of the present invention, the metal sheet is bonded to the outer insulation layer of the A-phase power line.

[0036] In some embodiments of the present invention, the metal sheet is in the form of a semi-circle surrounding the A-phase power line.

[0037] In some embodiments of the present invention, the motor is a three-phase asynchronous variable frequency motor or a three-phase asynchronous AC single-speed motor.

[0038] In some embodiments of the present invention, in step A, the no-load downstream current intensity I AD0 For: Real-time measurement or pre-existing computational units.

[0039] In some embodiments of the present invention, in step B, the no-load upward current intensity I AU0 For: Real-time measurement or pre-existing computational units.

[0040] In some embodiments of the present invention, in step C, the no-load downlink phase difference Δ φD0 For: Real-time measurement and calculation or pre-existing computational units.

[0041] In some embodiments of the present invention, in step D, the no-load uplink phase difference ΔφU0 For: Real-time measurement and calculation or pre-stored in the computing unit.

[0042] A second aspect of the present invention provides an elevator. The elevator includes: an elevator body; and the non-intrusive elevator load detection device as described above.

[0043] III. Beneficial Effects

[0044] As can be seen from the above technical solution, the present invention has at least one of the following beneficial effects compared to the prior art:

[0045] (1) In this invention, the voltage phase sensing structure and the transformer do not need to be connected to the elevator control system itself. They only need to be measured outside the A-phase power line. This will not affect the safety of the elevator and does not require any changes to the control system, which is more conducive to its widespread application.

[0046] (2) In this invention, the input power of the motor is detected under no-load conditions. Based on the known balance coefficient and the rated load of the elevator, a test is performed under no-load conditions. Since the efficiency of the motor changes significantly with load variations, while the efficiency of other systems remains relatively stable, and the active power of the motor can be measured relatively accurately, to reduce the influence of the elevator system efficiency on the test results, the relationship between the motor input power and the work done by the elevator under no-load conditions can be calculated. This relationship allows for relatively accurate measurement of the load state inside the elevator car under other load conditions by measuring the active power input of the motor.

[0047] (3) In the prior art, the voltage signal and the current signal are assumed to have the same delay. However, the applicant found that the two are not the same and the difference between them has a huge impact on the load calculation. Therefore, before calculating the phase difference, the present invention measures the delay value of the current signal and the voltage signal in real time, and then corrects the phase difference, which greatly improves the calculation accuracy.

[0048] (4) In this invention, during no-load testing, the inductance of the motor winding is calculated using the current flowing through the motor winding, the rated voltage of the variable frequency motor (or the output of the variable frequency drive), and the rated frequency. In subsequent testing, the voltage across the winding is calculated using the winding inductance, current, and frequency. This method fully utilizes the structural characteristics of elevators, eliminates the influence of unpredictable errors in non-contact voltage sensors on the testing results, and significantly improves the accuracy of non-contact power detection.

[0049] (5) In this invention, the motor winding voltage is calculated by the current in the coil, the power supply frequency, and the inductance of the motor winding. Since the measurement process occurs at the rated operating speed of the elevator, the power supply frequency is almost the same as that when measured under no-load conditions. This can reduce the error caused by the frequency change in the active power calculation formula. Not using a non-contact voltage sensor to collect the voltage can avoid the error caused by the influence of uncertain factors such as the environment on such sensors, thereby improving the accuracy of load calculation. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the hardware structure of the non-intrusive elevator load detection device according to an embodiment of the present invention.

[0051] Figure 2 for Figure 1 The diagram shows the control logic flow executed by the computing unit in the non-intrusive elevator load detection device. Detailed Implementation

[0052] The inventive concept of this invention lies in: obtaining voltage phase and frequency using a non-contact voltage phase detection method; measuring current through a current transformer; and determining the inductance of the variable frequency motor windings by adding the known voltage and frequency to the measured current value at the rated speed of the variable frequency motor. In subsequent measurements, the inductive reactance of the variable frequency motor windings can be calculated by measuring the inverter output frequency or the motor power supply frequency. The voltage across the variable frequency motor windings is then calculated using the current detected by the current transformer. The voltage phase detected by the non-contact phase sensor is compared with the current phase detected by the current transformer to determine the phase difference, and the active power consumed by the variable frequency motor is calculated.

[0053] Based on the above inventive concept, in order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0054] The first aspect of the present invention provides a non-intrusive elevator load detection device. Figure 1 This is a schematic diagram of the hardware structure of the non-intrusive elevator load detection device according to an embodiment of the present invention. Figure 1 As shown, the non-intrusive elevator load detection device in this embodiment includes:

[0055] The voltage phase sensing structure 10 is set around the A-phase power line of the variable frequency motor, wherein the A-phase power line is any one of the three-phase power lines of the variable frequency motor.

[0056] The current transformer 20 is installed around the A-phase power line of the variable frequency motor;

[0057] Transmitter 30 is connected to the voltage phase sensing structure and the current transformer, and is used to condition the received voltage phase sensing structure signal and current transformer signal to obtain voltage phase sensing signal and current sensing signal respectively.

[0058] The arithmetic unit 40 is used to calculate the load of the elevator car under the current state by using the voltage phase sensing signal and current sensing signal provided by the transmitter, combined with the rated parameters of the elevator variable frequency motor.

[0059] The following is a detailed description of each component of the non-intrusive elevator load detection device in this embodiment.

[0060] In this embodiment, phase A power line is used as an example for explanation. In other embodiments of the present invention, the voltage phase sensing signal and current sensing signal can be measured by selecting any one phase power line of the variable frequency motor.

[0061] In this embodiment, a three-phase asynchronous variable frequency motor is used as an example for illustration. However, the present invention is not limited thereto. In other embodiments of the present invention, the elevator motor can also be a three-phase asynchronous AC single-speed elevator. It should be specifically noted that the present invention is not applicable to AC three-phase dual-speed and multi-speed elevators.

[0062] In this embodiment, phase A power line is any one of the three-phase power lines of the variable frequency motor. In other words, any one of the three-phase power lines can be used to implement this invention.

[0063] In this embodiment, the voltage phase sensing structure is a semi-circular metal sheet surrounding the insulation layer of the A-phase power line. The power line insulation layer acts as a dielectric, and a capacitor is formed between the power line conductor and the semi-circular metal sheet. The voltage change trend is understood by measuring the AC signal passing through the capacitor, thereby obtaining the voltage phase in the A-phase power line. Those skilled in the art should understand that the voltage phase sensing structure does not actually measure the true voltage, but rather the differential voltage signal after the AC current passes through the capacitor. The processing unit then obtains the voltage phase information from this differential voltage signal.

[0064] It should be noted that this embodiment uses a voltage phase sensing mechanism in the form of a semi-circular metal sheet as an example for illustration, but the present invention is not limited thereto. In other embodiments of the present invention, the voltage phase sensing mechanism can also be an arc-shaped metal sheet of other shapes surrounding the insulation layer of the A-phase power line. This arc-shaped metal sheet can be tightly attached to the insulation layer of the A-phase power line, or it can be positioned at a distance from the insulation layer of the A-phase power line; both can achieve the present invention and are within the scope of protection of the present invention.

[0065] In this embodiment, the current transformer is disposed around the insulation layer of the A-phase power line of the variable frequency motor. The current transformer is a commonly used measuring instrument in the field, which can conveniently measure the amplitude and phase of the current in the power line; further details are omitted here.

[0066] Please refer to Figure 1 In this embodiment, the transmitter 30 is connected to the voltage sensing element and the current transformer to condition the received voltage phase sensing structure signal to obtain a voltage phase sensing signal; and to condition the received current transformer signal to obtain a current sensing signal.

[0067] Those skilled in the art should understand that the term "transmitter" here is a general term, encompassing any element, circuit, or device capable of shaping or conditioning signals in any form, all of which fall within the scope of this invention. Transmitters are common measuring instruments in the field and will not be described in detail here.

[0068] In this embodiment, apart from the signals sensed by the voltage phase sensing structure and the current transformer, all other parameters used for load calculation can be obtained from the elevator inverter or the motor itself. Furthermore, the voltage phase sensing structure and current transformer do not need to be connected to the elevator control system itself; measurements can be taken only outside the A-phase power line. This does not affect elevator safety, requires no changes to the control system, and is more conducive to widespread application.

[0069] Figure 2 for Figure 1 The diagram shows the control logic flow executed by the processing unit in the non-intrusive elevator load detection device. Please refer to it. Figure 1 and Figure 2 The control logic executed by the arithmetic unit includes:

[0070] Step A: Obtain the current intensity of phase A power line under no-load down-flow conditions - no-load down-flow current intensity I AD0 ;

[0071] Step B, obtain the current intensity of phase A power line under no-load upward state - no-load upward current intensity I AU0 ;

[0072] Step C yields the phase difference between the current phase and the voltage phase in the A-phase power line under no-load down-flow conditions - the no-load down-flow phase difference Δ. φD0 ;

[0073] Step D: Obtain the phase difference between the voltage phase and the current phase in the A-phase power line under no-load upward conditions - the no-load upward phase difference Δ. φU0 ;

[0074] Step E: Under the current load condition, obtain the current intensity of phase A power line - current current intensity I through the current sensing signal. Ax ;

[0075] Step F: In the current state, obtain the phase difference Δ between the current phase and the voltage phase in the A-phase power line, which is the current phase difference lags behind the voltage phase, using the voltage phase sensing signal and the current sensing signal. φx ;

[0076] Step G, utilizing the no-load downstream current intensity I of phase A power line AD0 No-load upward current intensity I AU0 ; No-load downlink phase difference Δ φD0 No-load uplink phase difference Δ φU0 Current current intensity I Ax Current phase difference Δ φx The current load on the elevator car is calculated by combining the inverter output voltage or power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator rated speed, and the elevator balance coefficient k.

[0077] In existing technologies, the output torque of the elevator motor significantly reduces overall efficiency due to the transmission through the gearbox, traction system, car guiding system, and the piston effect of the car in the hoistway. Efficiency varies for different elevators and cannot be accurately calculated. This invention utilizes the input power of the motor under no-load conditions. A test is performed based on a known balance coefficient and the elevator's rated load under no-load conditions. Since the motor efficiency varies considerably with load changes, while the efficiency of other systems remains relatively stable, and the motor's active power can be measured relatively accurately, the relationship between the elevator system efficiency and the elevator's work output under no-load conditions can be calculated to reduce the impact of elevator system efficiency on the test results. This relationship allows for relatively accurate measurement of the load state within the elevator car under other load conditions by measuring the active power input of the motor.

[0078] In this embodiment, the no-load downstream current intensity I in step A AD0 The no-load upward current intensity I in step B AU0 The no-load downlink phase difference Δ in step C φD0 The no-load uplink phase difference Δ in step D φU0 All four parameters are obtained through real-time measurement and calculation of relevant parameters. However, this invention is not limited to this. In other embodiments of this invention, the above four parameters can also be pre-stored in the arithmetic unit after measurement and calculation, for direct use in subsequent calculations, which can also achieve this invention and is also within the scope of protection of this invention.

[0079] It should be noted that in step C, the no-load downward phase difference is "the phase difference of current lagging behind voltage", and in step D, the no-load upward phase difference Δ φU0This refers to the "phase difference between voltage and current." This is because when the elevator is unloaded, it is generating electricity when moving upwards, with the voltage leading; conversely, it is consuming electricity when moving downwards, with the current leading. Similarly, when fully loaded, it is generating electricity when moving downwards and consuming electricity when moving upwards.

[0080] Regarding steps A and E, it should be noted that in this embodiment, since the elevator balance coefficient is a known parameter, according to the working principle of the traction elevator, when the elevator is descending under no-load conditions, the input power of the elevator host is close to the working state of the elevator ascending under full load, and the input power of the motor is close to the maximum input power of the elevator. Measuring the power load coefficient at this point is the most convenient and can minimize the error.

[0081] In this embodiment, the following aspects need to be explained regarding the phase difference in steps C, D, and F. The energy form in the A-phase power line is a pulse width modulation wave; both the voltage phase sensing signal and the current sensing signal are pulse width modulation signals with the same modulation frequency as the pulse width modulation wave, but their phases are different.

[0082] Based on the above, the definition is as follows:

[0083] 1. Voltage zero phase

[0084] The moment when the voltage phase-induced signal changes from negative voltage to positive voltage is defined as the 0° phase of the voltage.

[0085] 2. Zero phase of current

[0086] The moment when the current-induced signal changes from negative voltage to positive voltage is defined as the 0° phase of the current.

[0087] 3. Voltage signal delay

[0088] Define the voltage signal delay T of the current sensor and transmitter in response to the current sensing signal. AY .

[0089] 4. Current signal delay

[0090] Define the current signal delay T of the voltage phase sensing signal from the voltage sensor and transmitter. VY Under the above definition,

[0091] Under no-load downward conditions, the phase difference Δ between the current lagging the voltage in the A-phase power line and the no-load downward phase is... φD0 :

[0092] Under no-load upward conditions, the no-load upward phase difference Δ of the voltage lagging the current in phase A power line φD0 :

[0093] Where T is the AC period of the pulse width modulation wave in phase A power line, ΔtD0 Δ is the lag time of the current relative to the voltage in the A-phase power line under no-load downward conditions. tU0 This refers to the lag time of the voltage relative to the current in the A-phase power line under no-load upward conditions.

[0094] The current phase difference Δ of the current lagging the voltage in the A-phase power line under the current load condition φx : Where T is the AC period of the pulse width modulation wave in phase A power line, Δ tx This represents the lag time of the current relative to the voltage in the A-phase power line under the current load condition.

[0095] Since the input of most widely used variable frequency elevator motors is converted from DC power by a three-phase fully controlled bridge inverter, the output sine wave is fitted with a pulse width modulation (PWM) wave. Current detection using current transformers is relatively mature and has high detection accuracy. However, non-contact voltage detection methods are affected by factors such as temperature, humidity, conductor insulation material, PWM wave carrier frequency, and interference signals, resulting in larger errors. Although the positive and negative half-cycles of the PWM wave are fitted with corresponding positive and negative pulse signals with varying pulse widths, the pulse direction is relatively easy to determine, even though the voltage amplitude is difficult to obtain accurately. Current signals are accurately detected for amplitude and zero-crossing points using current transformers, while voltage signals are only detected for zero-crossing points to calculate the voltage-current phase difference.

[0096] In this embodiment, the energy in the A-phase power line is a pulse width modulation (PWM) wave. However, this is not an example of the present invention. In other embodiments of the present invention, the energy in the A-phase power line can also be a sine wave, which is equally applicable to the present invention and also within the scope of protection of the present invention.

[0097] It should be noted that existing technologies assume that voltage and current signals have the same delay, thus having no impact on the calculation of the phase difference. However, the applicant discovered that they are not the same, and the difference between them has a significant impact on load calculation. Therefore, the applicant calculates the phase difference Δ... φD0 Δ φU0 Δ φx First, the delay value after measuring the current signal and voltage signal is realized, and then the phase difference Δ is calculated. φD0 Δ φU0 Δ φx The corrections significantly improved the calculation accuracy.

[0098] In this embodiment, step G in the logic executed by the arithmetic unit further includes:

[0099] Sub-step G1, based on the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f, and the no-load downward current intensity I. AD0Calculate the inductance L of the motor winding:

[0100] It should be noted that U and f above can be parameters on the nameplate of the frequency converter or motor, or they can be output parameters of the frequency converter that can be obtained from technical data sheets, while the no-load current intensity I... AD0 The current is measured by the current transformer of phase A power line under no-load down-flow conditions, or it is pre-stored in the calculation unit after measurement for subsequent calculation.

[0101] To calculate the inductance of the motor windings, the influence of the windings themselves is considered, but this can be disregarded. The main purpose of calculating the inductance L is to subsequently calculate the voltage based on the current. Non-invasive voltage detection is not accurate enough, as it is affected by factors such as materials, temperature, humidity, the carrier frequency of the pulse width modulation wave, and installation. Therefore, the calculated voltage is far more accurate than detection correction, significantly improving the accuracy of elevator car load calculations.

[0102] Sub-step G2: Calculate the active power of the motor under no-load downward operation of the elevator - the active power P under no-load downward operation. kD0 Utilizing the no-load downlink active power P kD0 Calculate the load power factor Q kD ;

[0103] It should be noted that while the aforementioned steps yielded the current value and the phase difference between the voltage and current, accurate voltage values ​​are still needed to calculate active power. Since the winding parameters of the same motor are fixed, this invention utilizes this characteristic to calculate the inductance of the motor windings during no-load testing using the current flowing through the motor windings, the rated voltage of the variable frequency motor (or the output of the frequency converter), and the rated frequency. In subsequent testing, the voltage across the windings is calculated using the winding inductance, current, and frequency. This method fully leverages the structural characteristics of elevators, eliminating the influence of unpredictable errors from contactless voltage sensors on the detection results, and significantly improving the accuracy of contactless power detection.

[0104] However, the values ​​detected so far only represent the power of one phase of the three-phase power input, and due to the influence of various interference factors, there is still an unpredictable error compared to the true value of the active power. However, the change in this power is linear and closely related to the change in the elevator load, and the load condition of the elevator can be calculated through this correspondence.

[0105] When the elevator is descending unloaded, the counterweight is heavier than the car, so the variable frequency motor is in an energy-consuming state. Since the elevator's rated load and balance coefficient are known, the difference in mass between the counterweight and the car can be calculated by multiplying the rated load by the balance coefficient. This allows us to measure the power P during the unloaded descent. kDThe lifting force corresponding to each kilowatt of output power per phase can be calculated by considering the weight lifted by the variable frequency motor through the elevator traction system during unloaded downward movement. Since all elevator variable frequency motors use three-phase three-wire power supply and the winding parameters are fixed, the active power of each phase increases proportionally with the increase in output torque. This correspondence is essential for calculating the elevator's real-time load status.

[0106] Based on the above, in this sub-step, the active power of the motor in the elevator's unloaded downward operation is: Furthermore, the no-load download power factor Q kD for: Where Q is the elevator's rated load and k is the elevator's balance coefficient.

[0107] According to industry standards, balance coefficient tests must be performed on elevators before they are put into use and at specific time points. The results must be recorded in a file that is kept for the elevator's entire lifespan and can be easily obtained. If this parameter changes subsequently, it needs to be measured again.

[0108] Sub-step G3: Calculate the active power of the motor under no-load upward operation of the elevator - active power P under no-load upward operation. kU0 Utilizing the no-load uplink active power P kU0 Calculate the unloaded uplink load power factor Q kU ;

[0109] When the elevator is traveling upwards without a load, the counterweight is heavier than the car, so the variable frequency motor is in generator mode. Since the elevator's rated load and balance coefficient are known, the difference in mass between the counterweight and the car can be calculated by multiplying the rated load by the balance coefficient. This allows us to measure the power P during the unloaded upward travel. kU By calculating the driving force of the elevator motor corresponding to each kilowatt of output power per phase, based on the difference in mass between the car and counterweight during unloaded upward travel and the power generated by the motor driven by the elevator traction system, we can determine the driving force of the motor on the car and counterweight mass difference. Since all elevator variable frequency motors use three-phase three-wire power supply and the winding parameters are fixed, the active power generated by each of the three phases increases proportionally with an increase in input torque. Only by following this correspondence can the real-time load status of the elevator be calculated.

[0110] Based on the above, in this sub-step, the active power of the motor in the elevator's unloaded upward travel condition is:

[0111] Furthermore, the load power factor Q kU for: Where Q is the elevator's rated load and k is the elevator's balance coefficient.

[0112] The remaining features are the same as those in sub-step G2, and will not be repeated here.

[0113] Sub-step G4 utilizes the current phase difference Δ φx Current current intensity I Ax The inductance L of the motor winding is selected using the no-load downstream load power factor Q. kD Or the no-load uplink load power factor Q kU The current load on the elevator car is calculated using the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator's rated speed, and the elevator balance coefficient k. Specifically, the current load condition is divided into the following two cases.

[0114] (1) When 0° < Δ φx When the angle is ≤90°, the active power of the motor is: P kx =L2πf(I AD0 ·I Ax cos(Δ φx The current load on the elevator car is:

[0115] (2) When 90° < Δ φx When the angle is less than 180°, the active power of the motor is: P kx =L2πf(I AU0 ·I Ax cos(180-Δ) φx The current load on the elevator car is:

[0116] Specifically, the active input power of the variable frequency motor's A phase under the elevator's unloaded downward running condition is calculated using the active power of the elevator; the car load corresponding to the active input power of the variable frequency motor's A phase under the elevator's current load and the elevator's positive running direction is calculated using the active power of the elevator.

[0117] In this invention, the motor winding voltage is calculated using the current in the coil, the power supply frequency, and the inductance of the motor winding. Since the measurement process occurs at the rated operating speed of the elevator, the power supply frequency is almost the same as that during no-load measurement, which can reduce the error caused by frequency changes in the active power calculation formula. By not using a non-contact voltage sensor to collect the voltage, the error caused by such sensors being affected by uncertain factors such as the environment can be avoided, thereby improving the accuracy of load calculation.

[0118] This concludes the introduction to the non-intrusive elevator load detection device in this embodiment.

[0119] Based on the non-intrusive elevator load detection device described in the above embodiments, a second aspect of the present invention provides an elevator. The elevator includes: an elevator body; and the non-intrusive elevator load detection device as described above.

[0120] Regarding the elevator body, please refer to the relevant descriptions in the existing technology. Regarding the non-intrusive elevator load detection device, all the contents of the above embodiments are incorporated into this embodiment for reference.

[0121] This concludes the description of the various embodiments of the present invention. Based on the above description, those skilled in the art should have a clear understanding of the present invention.

[0122] It should be noted that for certain implementation methods, if they are not the key content of this invention and are well known to those skilled in the art, they are not described in detail in the accompanying drawings or text due to space limitations. In such cases, they can be understood by referring to the relevant prior art.

[0123] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by the computing device, or fabricating them separately as individual integrated circuit modules, or fabricating multiple modules or steps as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0124] Similarly, it should be understood that, for the sake of brevity, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of invention should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, the various inventive aspects consist of fewer than all the features of the preceding single embodiment. Furthermore, embodiments may be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0125] The above specific embodiments have provided a detailed description of the purpose, technical means, and beneficial effects of the present invention. It should be understood that the purpose of the detailed description is to enable those skilled in the art to better understand the present invention, and it is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-invasive elevator load detection device, characterized in that, include: A voltage phase sensing structure is installed around the A-phase power line of the motor, wherein the A-phase power line is any one of the three-phase power lines of the motor. The current transformer is installed around the A-phase power line of the motor; A transmitter, connected to the voltage phase sensing structure and the current transformer, is used to condition the received voltage phase sensing structure signal and current transformer signal to obtain voltage phase sensing signal and current sensing signal respectively. The arithmetic unit is used to execute the following logic: Step A: Obtain the current intensity of phase A power line under no-load down-flow conditions - no-load down-flow current intensity I AD0 ; Step B, obtain the current intensity of phase A power line under no-load upward state - no-load upward current intensity I AU0 ; Step C, obtain the phase difference of the current lagging voltage of phase A power line under no-load down-flow condition - no-load down-flow phase difference Δ φD0 ; Step D: Obtain the phase difference between the voltage and current lag of phase A power line under no-load upward conditions - the no-load upward phase difference Δ. φU0 ; Step E: Under the current load condition, obtain the current intensity of phase A power line - current current intensity I through the current sensing signal. Ax ; Step F: Under the current load condition, obtain the phase difference between the current lag voltage and the current phase difference Δ of the A-phase power line through the current sensing signal and the voltage phase sensing signal. φx ; Step G, utilizing the no-load downstream current intensity I of phase A power line. AD0 No-load upward current intensity I AU0 ; No-load downlink phase difference Δ φD0 No-load uplink phase difference Δ φU0 Current current intensity I Ax Current phase difference Δ φx The current load on the elevator car is calculated by combining the inverter output voltage or power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator rated speed, and the elevator balance coefficient k.

2. The non-intrusive elevator load detection device according to claim 1, characterized in that, The energy in the A-phase power line is in the form of a pulse width modulation wave or a sine wave; the voltage phase sensing signal and the current sensing signal are both pulse width modulation signals or sine wave signals with the same modulation frequency as the pulse width modulation wave, but their phases are different. In steps C, D, and F of the logic executed by the arithmetic unit: the moment when the voltage phase sensing signal changes from negative to positive voltage is defined as the 0° phase of the voltage; the moment when the current sensing signal changes from negative to positive voltage is defined as the 0° phase of the current; and the voltage signal delay T of the current sensor and transmitter for the current sensing signal is defined as... AY Define the current signal delay T of the voltage phase sensing signal from the voltage sensor and transmitter. VY ; In step C, the no-load downlink phase difference Δ φD0 : In step D, the no-load uplink phase difference Δ φU0 : In step F, the current phase difference Δ φx : Where T is the AC cycle of the pulse width modulation wave or sine wave in phase A power line, and Δ tD0 Δ is the lag time of the current relative to the voltage in the A-phase power line under no-load downward conditions. tU0 Δ is the lag time of the voltage relative to the current in phase A power line under no-load upward conditions. tx This represents the lag time of the current relative to the voltage in the A-phase power line under the current load condition.

3. The non-intrusive elevator load detection device according to claim 1, characterized in that, In the logic executed by the arithmetic unit, step G includes: Sub-step G1, based on the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f, and the no-load downward current intensity I. AD0 Calculate the inductance L of the motor winding; Sub-step G2: Calculate the motor active power under no-load downward operating conditions - no-load downward active power P kD0 Utilizing the no-load downlink active power P kD0 Calculate the unloaded download power factor Q kD ; Sub-step G3: Calculate the motor active power under no-load upward operation condition - no-load upward active power P kU0 Utilizing the no-load uplink active power P kU0 Calculate the unloaded uplink load power factor Q kU ; Sub-step G4, utilizing the current phase difference Δ φx Current current intensity I Ax The inductance L of the motor winding is selected using the no-load downstream load power factor Q. kD Or the no-load uplink load power factor Q kU Calculate the current load on the elevator car by taking the inverter output voltage or motor power supply voltage U, the inverter output frequency or motor power supply frequency f at the elevator rated speed, and the elevator balance coefficient k.

4. The non-intrusive elevator load detection device according to claim 3, characterized in that, In sub-step G1, the inductance L of the motor winding is:

5. The non-intrusive elevator load detection device according to claim 3, characterized in that, Q is the elevator's rated load, and k is the elevator's balance coefficient, where... In the sub-step G2 No-load downstream active power P kD0 for: No-load download power factor Q kD for: In the sub-step G3 No-load uplink active power P kU0 for: No-load uplink load power factor Q kU for:

6. The non-intrusive elevator load detection device according to claim 5, characterized in that, In sub-step G4, under the current load state... When 0° < Δ φx When the angle is ≤90°, the active power of the motor is: P kx =L2πf(I AD0 ·I Ax cos(Δ φx The current load on the elevator car is: or, When 90° < Δ φx When the angle is less than 180°, the active power of the motor is: P kx =L2πf(I AU0 ·I Ax cos(180-Δ) φx The current load on the elevator car is:

7. The non-intrusive elevator load detection device according to any one of claims 1 to 6, characterized in that, The voltage phase sensing structure is a metal sheet surrounding the A-phase power line.

8. The non-intrusive elevator load detection device according to claim 7, characterized in that, The metal sheet is bonded to the outer insulation layer of phase A power line; and / or The metal sheet is in the shape of a semi-circle surrounding the A-phase power line.

9. The non-intrusive elevator load detection device according to any one of claims 1 to 6, characterized in that, The motor is a three-phase asynchronous variable frequency motor or a three-phase asynchronous AC single-speed motor; and / or, In step A, the no-load downstream current intensity I AD0 For: real-time measurement or pre-existing computing units; and / or, In step B, the no-load upward current intensity I AU0 For: real-time measurement or pre-existing computing units; and / or, In step C, the no-load downlink phase difference Δ φD0 For: real-time measurement and calculation or pre-existing computational units; and / or, In step D, the no-load uplink phase difference Δ φU0 For: Real-time measurement and calculation or pre-stored in the computing unit.

10. An elevator, characterized in that, include: Elevator body; The non-intrusive elevator load detection device as described in any one of claims 1 to 9.

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