Method for calculating phase resistance of elevator motor and elevator detection system

Abstract

The application discloses a method for calculating phase resistance of an elevator motor and an elevator detection system. Three-phase voltage values of a three-phase motor are collected, and voltage phase angle values and line voltage effective values under a voltage resultant vector in two-phase coordinates are calculated based on the three-phase voltage values. Two-phase current values in three-phase current of the three-phase motor are collected, and current phase angle values and line current effective values under a current resultant vector in two-phase coordinates are calculated based on the two-phase current values. The elevator car running distance is calculated based on the voltage phase angle values. The power factor is calculated based on the voltage phase angle values and the current phase angle values. The moment when the elevator car passes through the elevator balance position is identified based on the elevator car running distance, and the motor phase resistance is calculated based on the power factor, the line voltage effective value and the line current effective value when the elevator passes through the balance position. The line voltage value and the line current value when the elevator passes through the balance position are extracted, so that the motor phase resistance can be quickly calculated, and theoretical support is provided for the fast detection and accurate calculation of the balance coefficient.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a method for calculating the phase resistance of an elevator motor and an elevator detection system. Background Art

[0002] Figure 1 The figure shows a schematic diagram of an elevator transmission system in the prior art. This current elevator transmission system primarily consists of a traction machine 1, a guide pulley 2, a wire rope 3, a car 4, and a counterweight 5. The wire rope 3 is wound around the traction sheave of the traction machine 1. One end of the wire rope 3 is connected to the elevator car 4, and the other end is connected to the counterweight 5 via the guide pulley 2. The gravity of the elevator car 4 and the counterweight 5 creates a mutual pressure between the wire rope 3 and the traction sheave. When the traction motor is running, the traction sheave and wire rope 3 tend to move relative to each other, generating static friction, which drives the elevator up and down.

[0003] The traditional method for detecting the balance coefficient of an elevator is to measure only the current for an AC motor and the current and voltage for a DC motor when the car and counterweight reach a balanced position. The balance coefficient is determined by plotting the current (or voltage) load curve and the intersection of the upward and downward curves. One end of the elevator wire rope is connected to the elevator car, and the other end is connected to the counterweight. The operation of the elevator is achieved through the static friction between the wire rope and the traction sheave. The balance coefficient of the elevator is an important parameter that affects the safe operation of the elevator. Therefore, the balance coefficient detection of the elevator is particularly important. At present, the balance coefficient of the elevator is detected by multiple detections of the elevator's operating data, by recording the elevator's operating data, and by calculations and drawing curves. When the elevator passes the balanced position, there are problems such as low efficiency of current and speed detection and insufficient detection accuracy. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology. The present invention provides a method for calculating the phase resistance of an elevator motor and an elevator detection system. By identifying the elevator's equilibrium position and extracting the line voltage and line current values ​​when the elevator passes through the equilibrium position, the motor phase resistance can be quickly calculated, providing theoretical support for the rapid detection and accurate calculation of the balance coefficient.

[0005] The present invention provides a method for calculating the phase resistance of an elevator motor, the method comprising:

[0006] Collecting three-phase voltage values ​​of a three-phase motor, and calculating a voltage phase angle value and a line voltage effective value under a voltage synthesis vector in two-phase αβ coordinates based on the three-phase voltage values;

[0007] Collecting two-phase current values ​​of the three-phase current of the three-phase motor, and calculating the current phase angle value and the line current effective value under the current synthesis vector in the two-phase αβ coordinates based on the two-phase current values;

[0008] Calculating the elevator car travel distance based on the voltage phase angle value;

[0009] Calculating a power factor based on the voltage phase angle value and the current phase angle value;

[0010] The moment when the elevator car passes through the elevator equilibrium position is identified based on the elevator car running distance, and the motor phase resistance is calculated based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position.

[0011] Furthermore, the calculating of the elevator car running distance based on the voltage phase angle value includes:

[0012] Calculate the voltage phase angle increment value at time t based on the voltage phase angle value at time t and the voltage phase angle value of the previous sampling period at time t;

[0013] Calculating the elevator car running speed at time t based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value;

[0014] The distance traveled by the elevator car is calculated based on the integral of the speed over time.

[0015] Furthermore, the voltage phase angle increment value at time t is calculated based on the voltage phase angle value at time t and the voltage phase angle value of the previous sampling period at time t, including:

[0016]

[0017] Among them, Δθ(t) is the voltage phase angle increment at time t, Ut1β is the projection of the voltage composite vector on the β-axis at time t1, Ut1α is the projection of the voltage composite vector on the α-axis at time t1, Utβ is the projection of the voltage composite vector on the β-axis at time t, and Utα is the projection of the voltage composite quantity on the α-axis.

[0018] Furthermore, the calculation of the elevator car running speed at time t based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value includes:

[0019] Calculate the angular frequency at time t based on the voltage phase angle increment;

[0020] The elevator car running speed Va(t) at time t is calculated based on the relationship between the voltage frequency and the angular frequency of the voltage vector, where:

[0021] Va(t)=Vr*fa(t) / fr=(1 / T*Δθ(t) / 2π)*Vr* / fr;

[0022] Va(t) is the speed of the elevator at time t, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, Δθ(t) is the voltage phase angle increment at time t, fa(t) is the frequency of the voltage at time t, ω(t) is the angular frequency of the voltage vector at time t, ω(t) = 1 / T*Δθ(t), T is the sampling period, and fa(t) = ω(t) / 2π.

[0023] Furthermore, the method further includes: calculating the elevator car travel distance Sa based on the integral of the speed over time, wherein:

[0024] Sa=∫Va(t)dt=∫((1 / T*Δθ(t) / 2π)*Vr* / fr)dt;

[0025] Where Sa is the elevator running distance, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, T is the sampling period, and Δθ(t) is the voltage phase angle increment at time t.

[0026] Furthermore, the calculating the power factor based on the voltage phase angle value and the current phase angle value includes:

[0027] Assume cosφ is the power factor, θ is the voltage phase angle, θ i is the current phase angle;

[0028]

[0029] Among them, Utα and Utβ are the projections of the motor voltage synthesis vector on the α-axis and β-axis in the two-phase αβ coordinates, and Itα and Itβ are the projections of the motor current synthesis vector on the α-axis and β-axis in the two-phase αβ coordinates.

[0030] Furthermore, the calculating of the motor phase resistance based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position includes:

[0031] Obtain the running data and down running data of the elevator car when it passes the elevator equilibrium position. The running data includes: the running line voltage Us on the motor, the running line current Is on the motor, and the running power factor The running data include: motor running line voltage Ux, motor running line current Ix, running power factor

[0032] The motor phase resistance Rs is calculated based on the upper running data and the lower running data, where:

[0033]

[0034] Rs is the motor phase resistance, and Ef is the elevator transmission efficiency.

[0035] Further, the method further comprises:

[0036] calculating the upgoing mechanical power and the downgoing mechanical power of the elevator car based on the motor phase resistance, the power factor, the line voltage effective value and the line current effective value when the elevator car passes the elevator balance position.

[0037] Further, the calculating the upgoing mechanical power and the downgoing mechanical power of the elevator car based on the motor phase resistance, the power factor, the line voltage effective value and the line current effective value when the elevator car passes the elevator balance position comprises:

[0038] calculating the downgoing mechanical power of the elevator car based on the motor phase resistance, the power factor, the line voltage effective value and the line current effective value when the elevator car passes the elevator balance position:

[0039]

[0040] wherein Ux is the motor downgoing line voltage, Ix is the motor downgoing line current, is the downgoing power factor, Nx is the elevator downgoing mechanical power, Ef is the elevator transmission efficiency, and Rs is the motor phase resistance;

[0041] calculating the upgoing mechanical power of the elevator car based on the motor phase resistance, the power factor, the line voltage effective value and the line current effective value when the elevator car passes the elevator balance position:

[0042]

[0043] wherein Us is the motor upgoing line voltage, Is is the motor upgoing line current, is the upgoing power factor, Ns is the elevator upgoing mechanical power, Ef is the elevator transmission efficiency, and Rs is the motor phase resistance.

[0044] The application further provides an elevator detection system for performing the method of calculating the motor phase resistance of the elevator.

[0045] The elevator detection system comprises:

[0046] a voltage vector calculation module for collecting three-phase voltage values of the three-phase motor and calculating voltage phase angle values and line voltage effective values under a voltage resultant vector in two-phase αβ coordinates based on the three-phase voltage values;

[0047] a current vector calculation module for collecting two-phase current values in three-phase current of the three-phase motor and calculating current phase angle values and line current effective values under a current resultant vector in two-phase αβ coordinates based on the two-phase current values;

[0048] an elevator running distance calculation module configured to calculate an elevator car running distance based on the voltage phase angle value;

[0049] a balance position determination module configured to determine a time when the elevator car passes through an elevator balance position based on the elevator car running distance, i.e., to determine whether the elevator is at the balance position;

[0050] a phase resistance calculation module configured to calculate a motor phase resistance based on the power factor, the line voltage effective value and the line current effective value when the elevator car passes through the elevator balance position.

[0051] The application provides a method for calculating a motor phase resistance of an elevator and an elevator detection system. The method comprises the following steps: collecting three-phase voltage values and two-phase current values of a three-phase motor, obtaining a voltage phase angle value, a line voltage effective value, a current phase angle value and a line current effective value in a voltage resultant vector in a two-phase αβ coordinate, calculating an elevator car running speed and an elevator car running distance required for calculating a balance coefficient by using the data in the resultant vector and parameters of the elevator, accurately determining a time when the elevator car passes through an elevator balance position by using the elevator car running distance, and calculating a motor phase resistance based on a power factor, a line voltage effective value and a line current effective value when the elevator car passes through the elevator balance position. The calculation processes are completed by using the voltage values and the current values of the three-phase motor, the elevator running data when passing through the balance position are calculated based on the real-time collected voltage values and current values, the motor phase resistance data can be quickly calculated, the calculation of the elevator balance coefficient is more accurate, the calculation of the elevator balance coefficient can be completed in real time, the calculation of the elevator balance coefficient is faster, and theoretical support and actual operation methods are provided for the quick detection and accurate calculation of the balance coefficient. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0053] Figure 1 is a schematic diagram of an elevator drive system in the prior art;

[0054] Figure 2 is a flowchart of the method for calculating the motor phase resistance of the elevator in the embodiment of the present application;

[0055] Figure 3 is a voltage resultant vector diagram in a three-phase UVW coordinate in the embodiment of the present application;

[0056] Figure 4 is a two-phase αβ coordinate voltage resultant vector diagram in the embodiment of the present application;

[0057] Figure 5 is a method flow diagram for calculating the mechanical power of an electric elevator in the embodiment of the present application;

[0058] Figure 6 is a structural diagram of an elevator detection system in the embodiment of the present application. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0060] Embodiment one:

[0061] The method for calculating the motor phase resistance of an elevator in the embodiments of the present application comprises the following steps: collecting three-phase voltage values of a three-phase motor, and calculating voltage phase angle values and line voltage effective values under a voltage resultant vector in two-phase αβ coordinates based on the three-phase voltage values; collecting two-phase current values in three-phase currents of the three-phase motor, and calculating current phase angle values and line current effective values under a current resultant vector in two-phase αβ coordinates based on the two-phase current values; calculating an elevator car running distance based on the voltage phase angle values; calculating a power factor based on the voltage phase angle values and the current phase angle values; identifying a moment when the elevator car passes through an elevator balance position based on the elevator car running distance, and calculating a motor phase resistance based on the power factor, the line voltage effective value and the line current effective value when the elevator car passes through the elevator balance position. Further, three-phase voltage values of the three-phase motor at time t are collected, the three-phase voltage values are converted into a voltage resultant vector in two-phase αβ coordinates through voltage Clark conversion, and voltage phase angle values and voltage effective values are calculated based on the voltage resultant vector.

[0062] Further, three-phase current values of the three-phase motor at time t are collected, the three-phase current values are converted into a current resultant vector in two-phase αβ coordinates through current Clark conversion, and current phase angle values and current effective values are calculated based on the current resultant vector.

[0063] Here, a car running speed of the elevator car is calculated according to the voltage phase angle values, the running speed is integrated with respect to time, and the running distance of the car is obtained, that is:

[0064] Sa=∫Va(t)dt=∫((1 / T*Δθ(t) / 2π)*Vr* / fr)dt;

[0065] Where Sa is the elevator running distance, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, T is the sampling period, and Δθ(t) is the voltage phase angle increment at time t.

[0066] In an embodiment of the present invention, the elevator car travel distance is calculated based on the voltage phase angle value; whether the elevator car travel distance is at the elevator equilibrium position is determined; if the elevator car travel distance is determined to be at the elevator equilibrium position, the motor phase resistance is calculated based on the line voltage effective value and the line current effective value. This method for calculating the motor phase resistance identifies the elevator equilibrium position and extracts the line voltage and line current values ​​when the elevator passes through the equilibrium position, thereby rapidly calculating the motor phase resistance, providing theoretical support for the rapid detection and accurate calculation of the balance coefficient.

[0067] Example 2:

[0068] Figure 2 A flow chart of a method for calculating the phase resistance of an elevator motor according to an embodiment of the present invention is shown. The method includes the following steps:

[0069] It should be noted that since the elevator motor is a three-phase balanced load (i.e., the effective values ​​of the three-phase currents or phase voltages are equal when the motor is running), the present invention adopts a vector transformation algorithm when calculating current and voltage to speed up the detection time and simplify the calculation.

[0070] S101, collecting three-phase voltage values ​​of a three-phase motor;

[0071] Here, collecting the three-phase voltage value of the elevator motor at time t includes: detecting the three-phase input power of the elevator motor through a voltage probe; performing proportional and filtering processing on the three-phase input power; and obtaining the three-phase voltage value based on analog-to-digital sampling conversion of the three-phase input power.

[0072] The present invention uses three high-voltage voltage probes, coupled with corresponding hardware circuits, as elevator motor voltage detection units, respectively for detecting the U-phase, V-phase, and W-phase voltages of the elevator motor. The CPU samples the voltages in real time, obtaining the instantaneous values ​​of the motor's U-phase, V-phase, and W-phase voltages. These instantaneous values ​​are then transformed using a Clark transform, converting the motor's composite voltage vector (three-phase coordinates (U, V, W)) into a composite voltage vector (two-phase coordinates (α, β)). An algorithm then calculates the effective value of the motor's line voltage. This algorithm can calculate the motor's line voltage effective value in a relatively short time (100 μs).

[0073] S102, voltage Clark transformation;

[0074] Specifically, the voltage acquisition method for three-phase motors uses a voltage probe to detect the three-phase U, V, and W input power of the elevator motor. The three-phase power is proportionally filtered and then sampled by the CPU analog-to-digital circuit (ADC) (assuming a sampling period of 100μs). After transformation, the instantaneous voltage values ​​are obtained: Uu, Uv, and Uw (Uu is the instantaneous value of the U-phase voltage, Uv is the instantaneous value of the V-phase voltage, and Uw is the instantaneous value of the V-phase voltage). This value is the amplitude of the voltage vector at that moment in the three-phase coordinate system. Because the magnitude and direction of the instantaneous voltage values ​​are constantly changing, calculation and processing are relatively difficult. Therefore, the voltage vectors are synthesized and vector-transformed. Because the synthesized voltage vector remains unchanged before and after the transformation (its magnitude, direction, and angular frequency remain unchanged), calculating and processing the synthesized and transformed voltage vectors is equivalent to calculating and processing the instantaneous voltage variables.

[0075] Here, the three-phase voltage values ​​of the three-phase motor at time t are collected, and based on the three-phase voltage values, the voltage phase angle value and the line voltage effective value under the voltage synthesis vector in the two-phase αβ coordinates are calculated.

[0076] That is, the three-phase voltage value is subjected to Clark transformation, and the transformation algorithm is as follows:

[0077]

[0078] Among them, Uα is the projection of the voltage composite vector on the α-axis, Uβ is the projection of the voltage composite vector on the β-axis, Uu is the instantaneous value of the U-phase voltage, Uv is the instantaneous value of the V-phase voltage, and Uw is the instantaneous value of the W-phase voltage.

[0079] Furthermore, the voltage synthesis vector before and after the transformation is as follows Figure 3 and Figure 4 As shown, Figure 3 It shows the voltage synthesis vector diagram in three-phase UVW coordinates in an embodiment of the present invention, Figure 4 The two-phase αβ coordinate voltage synthesis vector diagram in an embodiment of the present invention is shown, where Ut is the synthesis vector of the three-phase voltage of the motor at time t.

[0080] S103, calculating the voltage phase angle value;

[0081] Here, the three-phase voltage values ​​are subjected to Clark transformation to obtain the voltage synthesis vector in the two-phase αβ coordinates, and the voltage phase angle value at time t is obtained, which includes:

[0082] Assume that Ut is the voltage synthesis vector after vector transformation. After the three-phase voltage value is subjected to Clark transformation, in the αβ coordinates, the projection on the α axis is Utα, and the projection on the β axis is Utβ. Then

[0083]

[0084] Among them, θ is the phase angle, Utβ is the projection of the voltage synthesis vector at time t on the β axis, and Utα is the projection of the voltage synthesis quantity at time t on the α axis.

[0085] Furthermore, the phase angle of the voltage synthesis vector at time t is:

[0086]

[0087] Among them, θ is the phase angle, Utβ is the projection of the voltage synthesis vector on the β axis, and Utα is the projection of the voltage synthesis quantity on the α axis.

[0088] S104, calculating the voltage phase angle increment value;

[0089] The voltage phase angle increment calculation module is a calculation module for synthesizing the voltage vector phase angle increment after the voltage vector passes through one sampling cycle. Assuming that the original voltage vector phase angle is θ, after one sampling cycle, its phase angle is θ1, then the phase angle increment Δθ=θ1-θ (θ and θ1 can be calculated by the formula mentioned above Calculation), thereby calculating and obtaining the voltage phase angle increment.

[0090] That is, the voltage phase angle increment value at time t is calculated based on the voltage phase angle value at time t and the voltage phase angle value of the previous sampling period at time t, including:

[0091]

[0092] Among them, Δθ(t) is the voltage phase angle increment at time t, Ut1β is the projection of the voltage composite vector on the β-axis at time t1, Ut1α is the projection of the voltage composite vector on the α-axis at time t1, Utβ is the projection of the voltage composite vector on the β-axis, and Utα is the projection of the voltage composite quantity on the α-axis.

[0093] S105, calculating the voltage angular frequency value;

[0094] The voltage angular frequency calculation here is that its input is 1 sampling period T (here T is set to 100μs), the voltage phase angle increment Δθ, the phase angle increment within 1s is the angular frequency, here T is 0.0001s, so the angular frequency value of the motor voltage can be calculated, and the angular frequency at time t is:

[0095] ω(t)=Δθ(t) / T, where ω(t) is the angular frequency of the voltage at time t, and Δθ(t) is the voltage phase angle increment at time t.

[0096] S106. Calculate the elevator car running speed;

[0097] Specifically, calculating the elevator car running speed at time t based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value includes: calculating the elevator car running speed Va(t) at time t based on the relationship between the voltage frequency and the angular frequency of the voltage vector, wherein:

[0098] fa(t)=ω(t) / 2π=(1 / T*Δθ(t)) / 2π;

[0099] Va(t)=Vr*fa(t) / fr=(1 / T*Δθ(t) / 2π)*Vr* / fr;

[0100] Va(t) is the speed of the elevator at time t, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, Δθ(t) is the voltage phase angle increment at time t, fa(t) is the frequency of the voltage at time t, ω(t) is the angular frequency of the voltage vector at time t, ω(t) = 1 / T*Δθ(t), T is the sampling period, and fa(t) = ω(t) / 2π.

[0101] S107, calculating the elevator car travel distance;

[0102] Specifically, the elevator car travel distance Sa is calculated based on the integral of speed over time, where:

[0103] Sa=∫Va(t)dt=∫((1 / T*Δθ(t) / 2π)*Vr* / fr)dt;

[0104] Where Sa is the elevator running distance, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, T is the sampling period, and Δθ(t) is the voltage phase angle increment at time t.

[0105] S108, calculating the line voltage value;

[0106] It should be noted that here the effective value of the line voltage is calculated. In the voltage αβ coordinates, the modulus of the synthetic voltage vector is the effective value of the voltage, that is, the effective value of the voltage is:

[0107]

[0108] Where U is the effective value of the motor voltage, that is, the line voltage value, Uα is the projection of the voltage synthesis vector on the α-axis, and Uβ is the projection of the voltage synthesis vector on the β-axis.

[0109] S109, collecting two-phase current values ​​among the three-phase currents of the three-phase motor;

[0110] The present invention uses two high-precision Hall effect current sensors as elevator motor current detection units. These sensors synthesize the current vectors in the two-phase αβ coordinates using the current values ​​of two of the three-phase currents. Specifically, two high-precision Hall effect current sensors are used to detect the U-phase and V-phase currents of the elevator motor, respectively. The CPU samples the current sensors in real time, obtaining the instantaneous values ​​of the motor's U-phase and V-phase currents. These instantaneous values ​​are then subjected to a Clark transform, converting the motor's composite current vector in the three-phase coordinates (U, V, W) into a composite current vector in the two-phase coordinates (α, β). An algorithm is then used to calculate the effective value of the motor's line current. This algorithm can calculate the effective value of the motor's line current within a relatively short detection time, namely, one sampling period T (sampling the current values ​​of two of the three-phase currents once every 100 μs).

[0111] S110, current Clark transformation;

[0112] In the specific implementation process of the present invention, the two-phase current values ​​are subjected to Clark transformation to obtain the current composite vector in the two-phase αβ coordinates. That is, the instantaneous value is subjected to Clark transformation to convert the motor composite current vector of the three-phase coordinates (U, V, W) into the motor current composite vector of the two-phase coordinates (α, β). Then, through the algorithm, the current can be sampled only in the U and V phases. The current expression of the two-phase coordinates can be:

[0113]

[0114] Among them, Iα is the α-phase current after Clark transformation, Iβ is the β-phase current after Clark transformation, IU is the U-phase current in the three-phase current, and IV is the V-phase current in the three-phase current. The effective value of the motor line current is calculated. This algorithm can calculate the effective value of the motor line current in a relatively short time (100μs), that is, obtain the current synthesis vector.

[0115] S111, calculating the line current value;

[0116] It should be noted that in the calculation of the effective value of line current, in the current αβ coordinates, the modulus of the synthetic current vector is the effective value of the current, that is, the effective value of the current is the line current value.

[0117]

[0118] Where I is the effective value of the motor voltage, Iα is the projection of the current resultant vector on the α-axis, and Iβ is the projection of the current resultant vector on the β-axis.

[0119] S112, calculating the current phase angle value;

[0120] Here, the three-phase current values ​​are subjected to Clark transformation to obtain the current composite vector in the two-phase αβ coordinates, and the current phase angle value at time t is obtained:

[0121] Assume that It is the current synthesis vector after vector transformation. After the three-phase current value is subjected to Clark transformation, in the αβ coordinates, the projection on the α axis is Itα, and the projection on the β axis is Itβ. Then

[0122]

[0123] Among them, θ i is the phase angle, Itβ is the projection of the current synthesis vector at time t on the β axis, and Itα is the projection of the current synthesis quantity at time t on the α axis.

[0124] Furthermore, the phase angle of the current synthesis vector at time t is:

[0125]

[0126] Among them, θ i is the phase angle, Itβ is the projection of the current synthesis vector on the β axis, and Itα is the projection of the current synthesis quantity on the α axis.

[0127] S113. Calculate the power factor;

[0128] set up is the power factor, θ is the voltage phase angle, and θi is the current phase angle;

[0129]

[0130] Among them, Utα and Utβ are the projections of the motor voltage synthesis vector on the α-axis and β-axis in the two-phase αβ coordinates, and Itα and Itβ are the projections of the motor current synthesis vector on the α-axis and β-axis in the two-phase αβ coordinates.

[0131] Specifically, the power factor is calculated based on the voltage phase angle θ and the current phase angle θi. When the voltage phase angle θ and the current phase angle θi are equal, that is, there is no deviation between the current and voltage phase angles, the apparent power is the useful power, and the power factor is 1. When the voltage phase angle θ and the current phase angle θi are different, the product of the projection of the current in the voltage direction and the voltage is the useful work, and the power factor is the cosine value of the phase angle difference between the voltage vector and the current vector.

[0132] It should be noted that in steps S101 to S113, the three-phase voltage value and the three-phase current value can be collected at any time during the elevator balance detection process. As the three-phase voltage value and the two-phase current values ​​of the three-phase current are continuously collected, they can be continuously converted into the voltage phase angle value, line voltage value, line current value, and current phase angle value at the current moment. Then, the real-time elevator car running speed and the elevator car running distance can be calculated through the real-time voltage phase angle value, and the real-time power factor can be calculated from the current phase angle value and the voltage phase angle value. These real-time data need to be stored locally. The elevator car running speed, line voltage value, line current value, and power factor when the elevator car passes the balance position need to be involved in the calculation process of the motor phase resistance and the upward mechanical power and downward mechanical power of the elevator car.

[0133] S114, determining the elevator equilibrium position;

[0134] Specifically, here, whether the elevator reaches the elevator equilibrium position is determined by the elevator car running distance, that is, the elevator operating parameters at that moment are recorded by reaching the elevator equilibrium position. If it is recognized that the elevator car passes the elevator equilibrium position, the process proceeds to S115. If not, the elevator car running distance is continued to be calculated until it is recognized that the elevator car passes the elevator equilibrium position.

[0135] When the elevator car runs from the bottom floor to the top floor, the running distance of the elevator car is calculated and divided by 2 to obtain the distance the elevator car runs from the top floor to the equilibrium position.

[0136] Alternatively, when the elevator car runs from the top floor to the bottom floor, the running distance of the elevator car is calculated and divided by 2 to obtain the distance the elevator car runs from the bottom floor to the equilibrium position.

[0137] It should be noted that here, whether the elevator car passes through the elevator equilibrium position is identified based on the elevator car running distance, that is, whether the elevator car reaches the equilibrium position during operation is judged by the calculated elevator car running distance, so as to calculate the moment when the upper running state passes through the equilibrium position and the moment when the lower running state passes through the equilibrium position, and at the same time record the elevator operating parameters needed for these two moments, such as the elevator car running speed, power factor, line voltage effective value and line current effective value when the elevator car passes the elevator equilibrium position, etc. These elevator operating parameters require the calculation of the motor phase resistance, the upward mechanical power and downward mechanical power of the elevator car, and the elevator balance coefficient.

[0138] S115. Calculate the motor phase resistance.

[0139] It should be noted that the calculation of motor phase resistance is completed by calculating the effective value of line voltage, effective value of line current, elevator parameters, and power factor. When the elevator is running downward without load, the motor draws electrical energy from the grid and converts it into mechanical energy to drive the elevator. Assuming that the motor iron loss (eddy current loss) is ignored, the relationship between electrical power and mechanical power is as follows:

[0140]

[0141] Among them, Ux is the motor running line voltage, Ix is the motor running line current, is the lower operating power factor, E is the motor back electromotive force, Ef is the elevator transmission efficiency, and Rs is the motor phase resistance.

[0142] Simplifying the above formula, we can get:

[0143]

[0144] When the elevator is running upward without load, the motor is in a generating braking state, and mechanical energy drives the motor to generate electricity. Assuming that the motor iron loss (eddy current loss) is negligible, the relationship between electric power and mechanical power is as follows:

[0145]

[0146] Among them, Us is the line voltage on the motor, Is is the line current on the motor, is the upper operating power factor, E is the motor electromotive force (for the same motor, the up and down speeds are the same, so its value is equal to the back electromotive force), Ef is the elevator transmission efficiency (for the same elevator, the up and down speeds are the same, the efficiency is the same), and Rs is the motor phase resistance.

[0147] Further simplifying the above formula, we get:

[0148]

[0149] Formula Perform the transformation and get:

[0150]

[0151] Formula Transform and multiply both sides of the equation by Ef 2 ,get:

[0152]

[0153] By the formula and formula Adding them together, we get:

[0154]

[0155] Right now;

[0156]

[0157] Furthermore, the elevator transmission efficiency Ef is set based on the elevator parameters, and the phase resistance of the elevator system motor can be calculated by combining the upper running line voltage Us of the motor, the upper running line current Is of the motor, the lower running line voltage Ux of the motor, and the lower running line current Ix of the motor.

[0158] The method for calculating the motor phase resistance identifies the elevator's equilibrium position and converts the three-phase voltage and three-phase current values ​​into a voltage composite vector and a current composite vector in two-phase αβ coordinates through Clark transformation. This method can simplify the calculation of line voltage values, line current values, voltage phase values, and current phase values. By extracting the line voltage and line current values ​​when the elevator passes through the equilibrium position, the motor phase resistance can be quickly calculated, providing theoretical support for the rapid detection and accurate calculation of the balance coefficient.

[0159] The method in the embodiment of the present invention collects the three-phase voltage values ​​of the three-phase motor and the current values ​​of two of the three-phase currents, and obtains the voltage phase angle value, the line voltage effective value, the current phase angle value, and the line current effective value under the voltage composite vector in the two-phase αβ coordinate. The data under these composite vectors, combined with the elevator parameters, can be used to calculate the elevator car running speed and elevator car running distance required for balance coefficient calculation. The elevator car running distance can be used to accurately identify the moment when the elevator car passes the elevator equilibrium position. The motor phase resistance is then calculated based on the power factor, line voltage effective value, and line current effective value when the elevator car passes the elevator equilibrium position. These calculation processes are all based on the voltage and current values ​​of the three-phase motor. The entire calculation process calculates the elevator operation data passing the equilibrium position based on the voltage and current values ​​collected in real time, so that the motor phase resistance data can be quickly calculated, making the subsequent calculation of the elevator balance coefficient more accurate. The calculation of the elevator balance coefficient can be completed in real time during the elevator operation, making the subsequent calculation of the elevator balance coefficient more rapid.

[0160] Example 3:

[0161] Figure 5 The schematic diagram of the method for calculating the mechanical power of an elevator in an embodiment of the present invention is shown. The method for calculating the mechanical power of an elevator is based on the method for calculating the phase resistance of the motor. For steps S101 to S115, please refer to Figure 2 The detailed description in

[15] will not be repeated here. Here, the calculation of step S116 is explained as follows:

[0162] S116. Calculate the upward mechanical power and downward mechanical power of the elevator car.

[0163] When the elevator is running downward without load, the motor absorbs electrical energy from the grid and converts it into mechanical energy to drive the elevator. Assuming that the motor iron loss (eddy current loss) is negligible, the relationship between electrical power and mechanical power is as follows:

[0164]

[0165] Based on the above formula deformation, we can get:

[0166]

[0167] Among them, Ux is the motor running line voltage, Ix is the motor running line current, is the down-running power factor, Nx is the down-running mechanical power of the elevator, Ef is the elevator transmission efficiency, and Rs is the motor phase resistance.

[0168] When the elevator is running upward without load, the motor is in a generating braking state, and mechanical energy drives the motor to generate electricity. Assuming that the motor iron loss (eddy current loss) is negligible, the relationship between electric power and mechanical power is as follows:

[0169]

[0170] Based on the above formula deformation, we can get:

[0171]

[0172] Among them, Us is the line voltage on the motor, Is is the line current on the motor, is the operating power factor, Ns is the operating mechanical power of the elevator, Ef is the elevator transmission efficiency, and Rs is the motor phase resistance.

[0173] The mechanical power Nx of the elevator running downward and the mechanical power Ns of the elevator running upward are calculated through the motor phase resistance, thereby providing theoretical support and practical operation methods for the rapid detection of the balance coefficient of the elevator.

[0174] The method in the embodiment of the present invention collects the three-phase voltage values ​​of the three-phase motor and the current values ​​of two of the three-phase currents, and obtains the voltage phase angle value, the line voltage effective value, the current phase angle value, and the line current effective value under the voltage composite vector in the two-phase αβ coordinate. The data under these composite vectors, combined with the elevator parameters, can be used to calculate the elevator car running speed and elevator car running distance required for balance coefficient calculation. The elevator car running distance can be used to accurately identify the moment when the elevator car passes the elevator equilibrium position. Then, based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes the elevator equilibrium position, the motor phase resistance and the elevator car's upward and downward mechanical power are calculated. These calculation processes are all performed based on the voltage and current values ​​of the three-phase motor. The entire calculation process calculates the elevator operation data passing the equilibrium position based on the voltage and current values ​​collected in real time. This allows the motor phase resistance and the elevator car's upward and downward mechanical power data to be quickly calculated, making the subsequent calculation of the elevator balance coefficient more accurate. The calculation of the elevator balance coefficient can be completed in real time during the elevator operation, making the subsequent calculation of the elevator balance coefficient more rapid.

[0175] Example 4:

[0176] The embodiment of the present invention further provides an elevator detection system, which is used to execute the above method for calculating the phase resistance of the elevator motor and the method for calculating the mechanical power of the elevator operation. The specific implementation process of the method can be referred to Figures 2 to 5 Instructions in .

[0177] Specifically, Figure 6 The structure diagram of the elevator detection system in an embodiment of the present invention is shown. The elevator detection system includes: a voltage vector calculation module 10, a current vector calculation module 20, an elevator running distance calculation module 30, a balance position judgment module 40 and a phase resistance calculation module 50.

[0178] The voltage vector calculation module 10 is used to collect three-phase voltage values ​​of the three-phase motor, and calculate the voltage phase angle value and the line voltage effective value under the voltage synthesis vector in the two-phase αβ coordinates based on the three-phase voltage values.

[0179] Furthermore, the collecting of three-phase voltage values ​​of the three-phase motor and calculation of the voltage phase angle value and the effective value of the line voltage under the voltage synthesis vector in the two-phase αβ coordinates based on the three-phase voltage values ​​include: collecting the three-phase voltage values ​​of the three-phase motor at time t, transforming the three-phase voltage values ​​into the voltage synthesis vector in the two-phase αβ coordinates through the voltage Clark transformation, and calculating the voltage phase angle value and the effective value of the voltage based on the voltage synthesis vector.

[0180] The current vector calculation module 20 is configured to collect two-phase current values in three-phase currents of the three-phase motor, and calculate a current phase angle value and a line current effective value under a current resultant vector in two-phase αβ coordinates based on the two-phase current values.

[0181] Further, the collecting two-phase current values in three-phase currents of the three-phase motor, and calculating a current phase angle value and a line current effective value under a current resultant vector in two-phase αβ coordinates based on the two-phase current values includes: collecting three-phase current values of the three-phase motor at t time, transforming the three-phase current values into a current resultant vector in two-phase αβ coordinates through a current Clark transformation, and calculating the current phase angle value and the current effective value based on the current resultant vector.

[0182] The elevator running distance calculation module 30 is configured to calculate an elevator car running distance based on the voltage phase angle value.

[0183] Here, the calculating the elevator car running distance based on the voltage phase angle value includes: calculating a voltage phase angle increment value at t time based on the voltage phase angle value at t time and a voltage phase angle value at a previous sampling period of t time; calculating an elevator car running speed at t time based on a rated frequency of an elevator motor, a rated speed of an elevator car, and the voltage phase angle increment value; and calculating the elevator car running distance based on an integral of speed with respect to time.

[0184] Here, the calculating the voltage phase angle increment value at t time based on the voltage phase angle value at t time and the voltage phase angle value at the previous sampling period of t time includes:

[0185]

[0186] wherein Δθ(t) is the voltage phase angle increment value at t time, Ut1β is a projection of a voltage resultant vector at t1 time on a β axis, Ut1α is a projection of the voltage resultant vector at t1 time on an α axis, Utβ is a projection of the voltage resultant vector at t time on the β axis, and Utα is a projection of the voltage resultant vector on the α axis.

[0187] Here, the calculating the elevator car running speed at t time based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value includes:

[0188] calculating an angular frequency at t time based on the voltage phase angle increment value;

[0189] calculating the elevator car running speed Va(t) at t time based on a relationship between a frequency of the voltage and an angular frequency of the voltage vector, wherein:

[0190] Va(t) = Vr*fa(t) / fr = (1 / T*Δθ(t) / 2π)*Vr* / fr.

[0191] Va(t) is the speed of the elevator at time t, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, Δθ(t) is the voltage phase angle increment at time t, fa(t) is the voltage frequency at time t, ω(t) is the angular frequency of the voltage vector at time t, ω(t) = 1 / T * Δθ(t), T is the sampling period, and fa(t) = ω(t) / 2π. The elevator car travel distance calculated based on the integral of speed over time includes:

[0192] The elevator car travel distance Sa is calculated based on the integral of speed over time, where:

[0193] Sa=∫Va(t)dt=∫((1 / T*Δθ(t) / 2π)*Vr* / fr)dt;

[0194] Where Sa is the elevator running distance, Vr is the rated speed of the elevator, fr is the rated frequency of the elevator, T is the sampling period, and Δθ(t) is the voltage phase angle increment at time t.

[0195] The voltage vector calculation module 10 and the current vector calculation module 20 may calculate a power factor based on the voltage phase angle value and the current phase angle value.

[0196] The equilibrium position judgment module 40 is used to identify the moment when the elevator car passes the elevator equilibrium position based on the elevator car running distance, that is, to judge whether the elevator is in the equilibrium position. The voltage vector calculation module 10 obtains the line voltage value, voltage phase angle value and other data of the elevator in the equilibrium position. The current vector calculation module 20 obtains the line current value, current phase angle and other data of the elevator in the equilibrium position. By obtaining the relevant voltage data and current data when the elevator passes the equilibrium position when going up and down, theoretical support and practical operation methods are provided for the rapid detection and accurate calculation of the elevator balance coefficient.

[0197] The phase resistance calculation module 50 calculates the motor phase resistance based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position.

[0198] Here, the motor phase resistance is calculated based on the power factor, the effective value of the line voltage, and the effective value of the line current when the elevator car passes through the elevator equilibrium position, including:

[0199] Obtain the running data and down running data of the elevator car when it passes the elevator equilibrium position. The running data includes: the running line voltage Us on the motor, the running line current Is on the motor, and the running power factor The running data include: motor running line voltage Ux, motor running line current Ix, running power factor

[0200] calculating motor phase resistance Rs based on the upper running data and the lower running data, wherein:

[0201]

[0202] Rs is the motor phase resistance, and Ef is the elevator drive efficiency.

[0203] The elevator detection system in the embodiment of the application further relates to an up-down mechanical power calculation module, which is used for calculating the up mechanical power and the down mechanical power of the elevator car based on the motor phase resistance, the power factor when the elevator car passes the elevator balance position, the line voltage effective value and the line current effective value.

[0204] Here, the up mechanical power and the down mechanical power of the elevator car are calculated based on the motor phase resistance, the power factor when the elevator car passes the elevator balance position, the line voltage effective value and the line current effective value, and the calculation includes:

[0205] The down mechanical power of the elevator car is calculated based on the motor phase resistance, the power factor when the elevator car passes the elevator balance position, the line voltage effective value and the line current effective value, and the calculation includes:

[0206]

[0207] wherein Ux is the motor lower running line voltage, Ix is the motor lower running line current, is the lower running power factor, Nx is the elevator lower running mechanical power, Ef is the elevator drive efficiency, and Rs is the motor phase resistance;

[0208] The up mechanical power of the elevator car is calculated based on the motor phase resistance, the power factor when the elevator car passes the elevator balance position, the line voltage effective value and the line current effective value, and the calculation includes:

[0209]

[0210] wherein Us is the motor upper running line voltage, Is is the motor upper running line current, is the upper running power factor, Ns is the elevator upper running mechanical power, Ef is the elevator drive efficiency, and Rs is the motor phase resistance.

[0211] In the embodiment of the application, the running distance of the elevator car is calculated based on the voltage phase angle value; it is judged whether the running distance of the elevator car is at the elevator balance position, and if the running distance of the elevator car is at the elevator balance position, the motor phase resistance is calculated based on the line voltage effective value and the line current effective value.

[0212] The system in the embodiment of the present invention collects the three-phase voltage values ​​of the three-phase motor and the current values ​​of two of the three-phase currents, and obtains the voltage phase angle value, the line voltage effective value, the current phase angle value, and the line current effective value under the voltage composite vector in the two-phase αβ coordinate. The data under these composite vectors, combined with the elevator parameters, can be used to calculate the elevator car speed and elevator car travel distance required for balance coefficient calculation. The elevator car travel distance can accurately identify the moment when the elevator car passes the elevator equilibrium position. The motor phase resistance is then calculated based on the power factor, line voltage effective value, and line current effective value when the elevator car passes the elevator equilibrium position. These calculation processes are all based on the voltage and current values ​​of the three-phase motor. The entire calculation process calculates the elevator operation data passing the equilibrium position based on the voltage and current values ​​collected in real time, allowing the motor phase resistance data to be calculated quickly, making the subsequent calculation of the elevator balance coefficient more accurate. The calculation of the elevator balance coefficient can be completed in real time during the elevator operation, making the subsequent calculation of the elevator balance coefficient more rapid.

[0213] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0214] In addition, the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for calculating the phase resistance of an elevator motor, characterized in that: The method comprises: Collecting three-phase voltage values ​​of a three-phase motor, and calculating a voltage phase angle value and a line voltage effective value under a voltage synthesis vector in two-phase αβ coordinates based on the three-phase voltage values; Collecting two-phase current values ​​of the three-phase current of the three-phase motor, and calculating the current phase angle value and the line current effective value under the current synthesis vector in the two-phase αβ coordinates based on the two-phase current values; Calculating the elevator car travel distance based on the voltage phase angle value; Calculating a power factor based on the voltage phase angle value and the current phase angle value; Identifying a time point when the elevator car passes through an elevator equilibrium position based on the elevator car travel distance, and calculating a motor phase resistance based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position; The calculating the power factor based on the voltage phase angle value and the current phase angle value includes: set up is the power factor, is the voltage phase angle, is the current phase angle; ； in , are respectively the projections of the motor voltage synthesis vector on the α-axis and β-axis in the two-phase αβ coordinates, , are the projections of the motor current composite vector on the α-axis and β-axis in the two-phase αβ coordinates; The calculating of the motor phase resistance based on the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position includes: Obtain the running data and the down running data of the elevator car when it passes the elevator equilibrium position, and the running data includes: the running line voltage of the motor , the running line current of the motor , operating power factor The running data include: the motor running line voltage , the motor running line current , operating power factor ; Calculate the motor phase resistance based on the up-running data and down-running data ,in: is the motor phase resistance, is the elevator transmission efficiency.

2. The method for calculating the phase resistance of an elevator motor according to claim 1, wherein: Calculating the elevator car running distance based on the voltage phase angle value includes: Calculate the voltage phase angle increment value at time t based on the voltage phase angle value at time t and the voltage phase angle value of the previous sampling period at time t; Calculating the elevator car running speed at time t based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value; The distance traveled by the elevator car is calculated based on the integral of the speed over time.

3. The method for calculating the phase resistance of an elevator motor according to claim 2, wherein: The step of calculating the voltage phase angle increment at time t based on the voltage phase angle value at time t and the voltage phase angle value of the previous sampling period at time t includes: ； in, is the voltage phase angle increment at time t, for The projection of the voltage synthesis vector on the β axis at the moment, for The projection of the voltage synthesis vector on the α axis at the moment, for The projection of the voltage synthesis vector on the β axis at the moment, is the projection of the voltage composite on the α-axis.

4. The method for calculating the phase resistance of an elevator motor according to claim 3, wherein: The step of calculating the elevator car running speed at time t based on the rated frequency of the elevator motor, the rated speed of the elevator car, and the voltage phase angle increment value includes: Calculate the angular frequency at time t based on the voltage phase angle increment; The elevator car running speed Va(t) at time t is calculated based on the relationship between the voltage frequency and the angular frequency of the voltage vector, where: ； is the speed of the elevator at time t, is the rated speed of the elevator, is the rated frequency of the elevator, is the frequency of the voltage at time t, for The angular frequency of the voltage vector at time , , T is the sampling period, .

5. The method for calculating the phase resistance of an elevator motor according to claim 4, wherein: The calculation of the elevator car travel distance based on the integral of speed over time includes: The elevator car travel distance Sa is calculated based on the integral of speed over time, where: ； in, is the elevator running distance.

6. The method for calculating the phase resistance of an elevator motor according to any one of claims 1 to 5, characterized in that: The method further comprises: The upward mechanical power and downward mechanical power of the elevator car are calculated based on the motor phase resistance, the power factor, the line voltage effective value, and the line current effective value when the elevator car passes through the elevator equilibrium position.

7. The method for calculating the phase resistance of an elevator motor according to claim 6, wherein: The calculating of the upward mechanical power and the downward mechanical power of the elevator car based on the motor phase resistance, the power factor when the elevator car passes through the elevator equilibrium position, the line voltage effective value, and the line current effective value includes: The downward mechanical power of the elevator car is calculated based on the motor phase resistance, the power factor when the elevator car passes through the elevator equilibrium position, the line voltage effective value, and the line current effective value: ； in, It is the mechanical power for the elevator to run downward; The upward mechanical power of the elevator car is calculated based on the motor phase resistance, the power factor when the elevator car passes through the elevator equilibrium position, the line voltage effective value, and the line current effective value: ； in, Provides mechanical power for the elevator.

8. An elevator detection system, characterized in that: The elevator detection system is used to execute the method for calculating the phase resistance of an elevator motor according to any one of claims 1 to 7, and the elevator detection system includes: Voltage vector calculation module: used to collect the three-phase voltage values ​​of the three-phase motor and calculate the voltage phase angle value and line voltage effective value under the voltage synthesis vector in the two-phase αβ coordinates based on the three-phase voltage values; Current vector calculation module: used to collect two-phase current values ​​of the three-phase current of the three-phase motor, and calculate the current phase angle value and line current effective value under the current synthesis vector in the two-phase αβ coordinates based on the two-phase current values; Elevator running distance calculation module: used to calculate the elevator car running distance based on the voltage phase angle value; A balance position determination module is configured to identify the moment when the elevator car passes the elevator balance position based on the elevator car travel distance, that is, to determine whether the elevator is in the balance position; Phase resistance calculation module: used to calculate the motor phase resistance based on the power factor, the line voltage effective value and the line current effective value when the elevator car passes through the elevator equilibrium position.

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