A method for automatic debugging of frequency converter

Abstract

The present invention provides a frequency converter automatic debugging method, characterized in that it comprises the following steps: when the elevator is unloaded, the permanent magnet synchronous motor is subjected to the star-sealing operation, the brake is opened, and the elevator starts to slide slowly; when the elevator slides, the magnetic pole position is obtained and the magnetic pole code is calculated. When the Z-phase signal of the rotary encoder appears high level twice during the sliding process, the brake is closed, the star-sealing state is ended, and the sliding is ended; when the brake is closed, the current control PI parameter is automatically learned until the deviation between the command value and the feedback value of the current per unit time is minimized or the number of iterations reaches the set maximum value; the brake is opened, and the speed control PI parameter is automatically learned until the deviation between the command value and the feedback value of the speed per unit time is minimized or reaches a certain size relationship, or the number of iterations reaches the set maximum value. Through the above method, only the preset control parameters are retained, and the control parameter library will not increase with the increase of the specification configuration, saving the storage space occupied by the control parameter library and saving the chip cost.

Description

Technical Field

[0001] The invention relates to the technical field of elevator operation frequency converters, and in particular to an automatic debugging method for frequency converters. Background Art

[0002] During the elevator development phase, developers need to design appropriate control parameters for each elevator specification. Elevator specifications are complex, with different load and speed combinations, different motor configuration combinations, and different inverter specifications combinations, which generate a large number of parameters. Control parameters generally include motor parameters (such as pole number, back electromotive force, winding resistance and inductance, etc.), PI control parameters, etc. All these parameters must be stored in the memory to form a control parameter library, which occupies a large amount of storage resources; during the elevator design phase, designers need to select corresponding control parameters according to the elevator specifications in the existing control parameter library. Too many specifications often cause configuration errors; after the elevator is installed, the commissioning personnel need to confirm and debug each project on site, check whether the phase sequence of the motor line has been correctly connected according to the shaft configuration, and if it is not correct, the phase sequence needs to be readjusted, and then the motor's magnetic pole position and magnetic pole code need to be learned. The elevator can only operate reliably when all the above steps are correct. In order to achieve the above purpose, the control parameter library data is huge, occupies a lot of storage resources, and the chip price is expensive. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings of the prior art, the present invention aims at providing a method for automatic debugging of a frequency converter, which can reduce the occupation of storage resources and enable the elevator to operate reliably.

[0004] In order to achieve the purpose, the technical solution adopted by the present invention is as follows:

[0005] A frequency converter automatic debugging method comprises the following steps:

[0006] The elevator is unloaded, the permanent magnet synchronous motor is closed, and then the brake is opened, and the elevator starts to slide slowly; when the elevator slides, the magnetic pole position is obtained and the magnetic pole code is calculated.

[0007] When the Z-phase signal of the rotary encoder appears high level twice during the slipping process, the brake is closed, the star-locking state ends, and the slipping ends;

[0008] When the brake is closed, the current control PI parameters are automatically learned until the deviation between the command value and the feedback value of the current per unit time is minimized or the number of iterations reaches the set maximum value;

[0009] Open the brake and automatically learn the speed control PI parameters until the deviation between the speed command value and the feedback value per unit time is minimized or reaches a certain size relationship, or the number of iterations reaches the set maximum value;

[0010] After learning is completed, close the brake.

[0011] Preferably, the maximum distance of the sliding vehicle corresponds to twice the circumference of the motor traction wheel.

[0012] As a preferred embodiment, when the elevator is sliding, obtaining the magnetic pole position and calculating the magnetic pole code includes the following steps:

[0013] When the elevator slips, the current sensors installed on each phase line of the motor detect the phase relationship of the three-phase current of the motor, determine the phase sequence of the motor line, and automatically adjust the phase sequence definition of the motor connection;

[0014] Detect the number of single-phase current cycles between the Z phases of two adjacent motor shaft rotary encoders, thereby determining the number of motor poles;

[0015] Learn rotary encoder specifications;

[0016] Detect the real-time magnetic pole position and calculate the magnetic pole code.

[0017] Preferably, when the brake is closed, the current control PI parameters are automatically learned, including the following steps: a set of current control PI parameter initial values ​​with smaller values ​​are preset, a current command value is given, and a current feedback value is collected through a current sensor; the relationship between the current command value and the feedback value is observed, the PI parameters are adjusted, and then the adjusted PI parameters are readjusted to the output current, and this process is repeated.

[0018] As a preferred method, the brake is opened and the speed control PI parameters are automatically learned, including the following steps: the motor speed is controlled to 0 speed by a speed control method; a speed command value is given, the speed is adjusted by a set of speed control PI parameter initial values ​​with smaller preset values, and the speed feedback value is collected; according to the relationship between the speed command value and the feedback value, the PI parameters are adjusted, and then the motor speed is re-controlled to 0, or returned to the original position when the brake is opened, and then the motor speed is re-adjusted with the adjusted PI parameters, and this process is repeated.

[0019] Preferably, the speed control method includes a PI speed control method or a position control method.

[0020] Preferably, the method for measuring the minimum deviation is a method of minimum variance or minimum mean value or a method of relative size within a certain range.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Through the above method, only the preset control parameters are retained, and the control parameter library will not increase with the increase of specification configuration, which greatly saves the storage space occupied by the control parameter library and saves chip costs; designers do not need to select control parameters according to elevator specifications, avoid errors, and improve production efficiency; the motor main line phase sequence can be connected arbitrarily, with high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0024] Figure 1 This is the default phase sequence definition diagram of the inverter when it leaves the factory;

[0025] Figure 2 After the permanent magnet synchronous motor is closed, the elevator slips and the current phase relationship conforms to W->V->U. It can be defined according to the default phase sequence without change.

[0026] Figure 3 After the permanent magnet synchronous motor is closed, the elevator slips and the current phase relationship does not conform to W->V->U. The phase sequence definition needs to be changed and any two phase definitions need to be swapped.

[0027] Figure 4 This is the waveform diagram of the elevator slipping after the permanent magnet synchronous motor is shut down. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention, and the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0029] A frequency converter automatic debugging method according to the present invention comprises the following steps:

[0030] The elevator is unloaded, the permanent magnet synchronous motor is closed, and then the brake is opened, and the elevator starts to slide slowly; when the elevator slides, the magnetic pole position is obtained and the magnetic pole code is calculated.

[0031] When the Z-phase signal of the rotary encoder appears high level twice during the slipping process, the brake is closed, the star-locking state ends, and the slipping ends;

[0032] When the brake is closed, the current control PI parameters are automatically learned until the deviation between the command value and the feedback value of the current per unit time is minimized or the number of iterations reaches the set maximum value;

[0033] Open the brake and automatically learn the speed control PI parameters until the deviation between the speed command value and the feedback value per unit time is minimized or reaches a certain size relationship, or the number of iterations reaches the set maximum value;

[0034] After learning is completed, close the brake.

[0035] In order to implement the above debugging method, the following steps are specifically used:

[0036] The first step: make the elevator unloaded, implement the star-locking operation on the permanent magnet synchronous motor, then open the brake, and the elevator starts to slide slowly. When the Z-phase signal of the rotary encoder appears high level twice during the sliding process, close the brake, end the star-locking state, and end the sliding. The star-locking, that is, short-circuiting the three phases of the motor, can be short-circuited by a contactor or an IGBT.

[0037] The maximum distance of the car sliding corresponds to twice the circumference of the motor traction wheel. During the sliding process, the microcomputer system implements the following operations:

[0038] (1)Reference Figures 1 to 4 As shown, the phase relationship of the three-phase current of the motor is detected by the current sensor set on each phase line of the motor, the phase sequence of the motor line is determined, and the phase sequence definition of the motor wiring is automatically adjusted, thereby realizing the automatic adjustment of the arbitrary wiring of the motor line. Specifically, since the brake is opened when unloaded, the elevator car must slide downward, so the direction of rotation of the motor at this time is the downward direction of the car. When in the downward direction, the phase sequence of the motor current should be W->V->U (W leads V leads U) and the phase difference is 120°. The controller can obtain the phase sequence of the three-phase current according to the order of the positive or negative zero-crossing points of the current signal collected by the current sensor. When the phase sequence of the three-phase current does not conform to W->V->U, the phase sequence definition of the current sensor is adjusted to make the phase sequence of the three-phase current conform to W->V->U.

[0039] In order to save costs, three-phase motors are often only equipped with current sensors on two phases. In this case, the current of the third phase can be calculated based on the method that the algebraic sum of the three-phase currents is equal to 0.

[0040] (2) Detect the number of single-phase current cycles between the Z phases of the two adjacent motor shaft rotary encoders, thereby determining the number of motor poles. Specifically, each time the encoder rotates one circle, a Z-phase pulse will be generated. Therefore, by collecting the number of single-phase current cycles between two adjacent Z phases, the number of motor poles can be determined, and the number of motor poles is equal to the number of cycles multiplied by 2. In order to further improve the reliability, the number of three-phase current cycles between adjacent Z phases can also be recorded separately as a mutual check. If an encoder with U, V, W square wave signals of the same number of poles is configured, the number of motor poles can also be obtained based on the number of cycles of the U, V, W square wave signals between two adjacent Z phases. Among them, the number of motor poles is equal to the number of cycles of any one phase square wave multiplied by 2.

[0041] (3) Learn the rotary encoder specifications

[0042] Specifically, the controller collects the number of A and B phase pulses between two adjacent Z phases of the encoder, and can learn the resolution of the configured encoder, that is, how many pulses correspond to each revolution.

[0043] (4) Detecting real-time magnetic pole position

[0044] Specifically, the position of the magnetic pole on the rotating coordinate axis is equal to the phase current phase. In (1), the U phase line is determined, and the magnetic pole position can be converted according to the current phase on the predetermined U phase line. In fact, it is difficult to accurately detect the phase current phase. Here, the following method is adopted: First, detect the positive zero point of the U phase current (the current flows in the positive direction of the motor). When the positive zero point is passed, the magnetic pole position is 0°. Combined with the number of motor poles learned in (2), the number of A and B phase pulses corresponding to each pair of poles can be known. From the above 0° moment, the number of A and B phase pulses can be calculated to obtain the magnetic pole phase. For example, if the number of pole pairs of a motor is 4, and the number of A or B phase pulses corresponding to one circle is 1000, then the number of pulses corresponding to one pair of poles is 1000 / 4=250, that is, 250 pulses are equivalent to 360° electrical angle. The number of pulses n after 0° can be used to know that the current magnetic pole position is n / 250°×360°. In addition, in order to improve the resolution of the magnetic pole position, the A and B phase pulses can be orthogonal to double the accuracy.

[0045] (5) Calculate the magnetic pole code

[0046] Specifically, combined with the conclusion of (4), the magnetic pole position at the rising edge of the Z-phase pulse is the magnetic pole code. The magnetic pole code is equivalent to the relative relationship between the rotary encoder and the magnetic pole position. When the controller reads the encoder signal, it can convert it to the magnetic pole position through this relative relationship.

[0047] Step 2: Close the brake and automatically learn the current control PI parameters

[0048] A set of current control PI parameter initial values ​​with smaller preset values ​​are set, current commands are given, current feedback values ​​are collected through current sensors, the relationship between the current command value and the feedback value is observed, PI parameters are adjusted, and then the adjusted PI parameters are readjusted to the output current, and this is repeated until the deviation between the current command value and the feedback value per unit time is minimized or the number of iterations reaches the set maximum value. The above-mentioned method for adjusting PI parameters can be implemented by exhaustive method, etc. When the exhaustive method is adopted, for example, PI parameters are set from small to large, the control effect of each set of PI parameters is observed, and finally the best set is selected.

[0049] Step 3: Open the brake, automatically learn the speed control PI parameters, and close the brake after learning is completed

[0050] Open the brake, and control the motor speed to 0 speed through the speed control method (such as PI speed control, position control, etc.), then give the speed command, adjust the speed through a set of speed control PI parameter initial values ​​with a smaller preset value, observe the relationship between the speed command value and the feedback value, adjust the PI parameters, and then control the motor speed to 0 again, or return to the original position when the brake is opened, and then readjust the motor speed with the adjusted PI parameters, and repeat this process until the deviation between the speed command value and the feedback value per unit time is minimized or reaches a certain size relationship, or the number of iterations reaches the set maximum value. The method for adjusting the PI parameters mentioned above can be an exhaustive method, etc. When using the exhaustive method, for example, set the PI parameters from small to large, observe the control effect of each set of PI parameters, and finally select the one with the best effect.

[0051] In the second and third steps, the methods for measuring the minimum deviation include but are not limited to: minimum variance method, minimum mean value method, relative size within a certain range, etc. The maximum number of iterations affects the learning efficiency and learning accuracy. When pursuing learning efficiency, the number of iterations can be reduced, and when pursuing learning accuracy, the number of iterations can be increased.

[0052] Through the above method, elevators of different specifications can obtain the appropriate magnetic pole position, magnetic pole code, and PI parameters that can obtain the appropriate current value and speed value through learning and adjustment for elevator operation, which not only saves the storage space occupied by the control parameter library, but also ensures the normal and reliable operation of the elevator. By retaining only the preset control parameters, the control parameter library will not increase with the increase of specification configuration, saving the storage space occupied by the control parameter library and saving chip costs; designers do not need to select control parameters according to elevator specifications, avoid errors, and improve production efficiency; the motor main line phase sequence can be connected arbitrarily, with high efficiency.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for automatic debugging of a frequency converter, characterized in that , including the following steps: When the elevator is unloaded, the permanent magnet synchronous motor is closed, and then the brake is opened, and the elevator starts to slide slowly. When the elevator slides, the magnetic pole position is obtained and the magnetic pole code is calculated; When the Z-phase signal of the rotary encoder appears high level twice during the slipping process, the brake is closed, the star-locking state ends, and the slipping ends; When the brake is closed, the current control PI parameters are automatically learned until the deviation between the command value and the feedback value of the current per unit time is minimized or the number of iterations reaches the set maximum value; Open the brake and automatically learn the speed control PI parameters until the deviation between the speed command value and the feedback value per unit time is minimized or reaches a certain size relationship, or the number of iterations reaches the set maximum value; When the brake is closed, the current control PI parameters are automatically learned, including the following steps: a set of current control PI parameter initial values ​​with smaller values ​​are preset, a current command value is given, and a current feedback value is collected through a current sensor; the relationship between the current command value and the feedback value is observed, the PI parameters are adjusted, and then the adjusted PI parameters are readjusted to the output current, and this is repeated; Open the brake and automatically learn the speed control PI parameters, including the following steps: control the motor speed to 0 speed through the speed control method; give a speed command value, adjust the speed through a set of speed control PI parameter initial values ​​with smaller preset values, and collect the speed feedback value; adjust the PI parameters according to the relationship between the speed command value and the feedback value, and then control the motor speed to 0 again, or return to the original position when the brake is opened, and then readjust the motor speed with the adjusted PI parameters, and repeat this process.

2. The method for automatic debugging of a frequency converter according to claim 1, characterized in that , the maximum distance of the slipping car corresponds to twice the circumference of the motor traction wheel.

3. The method for automatic debugging of a frequency converter according to claim 1, characterized in that ,When the elevator is sliding, obtaining the magnetic pole position and calculating the magnetic pole code includes the following steps: When the elevator is slipping, the current sensors installed on each phase line of the motor detect the phase relationship of the three-phase current of the motor, so that the phase sequence of the three-phase current conforms to W->V->U; Determine the number of motor poles; Learn rotary encoder specifications; Detect the real-time magnetic pole position and calculate the magnetic pole code.

4. The frequency converter automatic debugging method according to claim 1, characterized in that ,The method to measure the minimum deviation is the method of minimum variance or minimum mean value or the method of relative size within a certain range.

5. The frequency converter automatic debugging method according to claim 3, characterized in that ,The current sensors arranged on each phase line of the motor detect the phase relationship of the three-phase current of the motor so that the phase sequence of the three-phase current conforms to W->V->U. Specifically, the following steps are included: the current sensors arranged on each phase line of the motor detect the phase relationship of the three-phase current of the motor and judge the phase sequence of the motor line. When the phase sequence of the three-phase current does not conform to W->V->U, the phase sequence definition of the current sensor is adjusted so that the phase sequence of the three-phase current conforms to W->V->U.

6. The frequency converter automatic debugging method according to claim 3, characterized in that ,Determine the number of motor poles, including the following steps: Detect the number of single-phase current cycles between the Z phases of two adjacent motor shaft rotary encoders, thereby determining the number of motor poles; Or when an encoder with U, V, W square wave signals having the same number of poles is configured, the number of motor poles is obtained according to the number of cycles of the U, V, W square wave signals between two adjacent Z phases.

7. The frequency converter automatic debugging method according to claim 6, characterized in that ,After determining the number of poles of the motor, record the number of three-phase current cycles between adjacent Z phases for mutual verification.

8. The frequency converter automatic debugging method according to claim 3, characterized in that The detection of real-time magnetic pole position includes the following steps: detecting the positive crossing point of the U-phase current, when the magnetic pole position is 0°; obtaining the number of A and B phase pulses corresponding to each pair of poles in combination with the number of motor poles; calculating the number of A and B phase pulses from the above 0° moment to obtain the magnetic pole position.

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