Method and device for detecting braking distance
阅读说明:本技术 制动距离的检测方法及装置 (Method and device for detecting braking distance ) 是由 王磊 朱传齐 欧明萍 杜国荣 于 2019-09-27 设计创作,主要内容包括:本申请公开了一种制动距离的检测方法及装置。该检测方法包括:获得从制动过程开始到制动结束的定子电压曲线;以及根据定子电压曲线的特征点个数获得制动距离。该检测方法通过采集定子电压曲线计算工作装置的制动距离,适用于制动距离的实时在线测量,仅需采集电机定子电压并通过分析、计算、处理,即可获得制动距离,无需额外安装传感器等装置,具有实现成本低、安装简单、接线方便、维护方便等诸多优点。(The application discloses a method and a device for detecting a braking distance. The detection method comprises the following steps: obtaining a stator voltage curve from the beginning of the braking process to the end of the braking; and obtaining the braking distance according to the number of the characteristic points of the stator voltage curve. The detection method is suitable for real-time online measurement of the braking distance by acquiring the stator voltage curve to calculate the braking distance of the working device, can obtain the braking distance by only acquiring the motor stator voltage and analyzing, calculating and processing the motor stator voltage, does not need to additionally install devices such as a sensor and the like, and has the advantages of low implementation cost, simplicity in installation, convenience in wiring, convenience in maintenance and the like.)
1. A braking distance detecting method for detecting a braking distance of a working device in a motor system, the motor system including a motor for driving the working device, a brake for braking the working device, and the working device, the detecting method comprising, after detecting a power failure of the motor:
obtaining a stator voltage curve from the beginning of the braking process to the end of the braking; and
and obtaining the braking distance according to the number of the characteristic points of the stator voltage curve.
2. The detection method according to claim 1, wherein the method of obtaining the stator voltage profile comprises repeatedly performing the steps of:
obtaining a sampling voltage;
obtaining the number of the characteristic points of the sampling voltage; and
it is judged whether the braking is finished or not,
and when the braking is judged to be finished, stopping obtaining the sampling voltage.
3. The detection method according to claim 1 or 2, wherein the stator voltage curve has a plurality of characteristic points, and a phase difference between adjacent two of the characteristic points is a predetermined value.
4. The detection method according to claim 3, wherein the feature point is a zero point, a peak point, or an intermediate point, and the number of feature points is the number of the zero point, the peak point, or the intermediate point.
5. The detection method according to claim 2, wherein the method of obtaining the sampled voltage comprises:
sampling the stator voltage to obtain a first voltage;
amplifying the first voltage to obtain a second voltage;
conditioning the second voltage to obtain the sampled voltage.
6. The detection method according to claim 2, wherein the method of obtaining the number of feature points comprises:
determining whether or not a voltage value of the sampled voltage is equal to a voltage value of the characteristic point after the sampled voltage is obtained,
if the voltage value of the sampling voltage is equal to the voltage value of the characteristic point, updating the number of the characteristic points,
if the voltage value of the sampling voltage is not equal to the voltage value of the characteristic point, the number of the characteristic points is not updated,
wherein the updated number of the feature points is equal to the number of the feature points before updating plus one.
7. The detection method according to claim 2, wherein the method of determining whether braking is over comprises:
obtaining the average amplitude of the stator voltage curve between the last collected characteristic point and the adjacent characteristic point; and
judging whether the average amplitude is smaller than a preset amplitude or not,
wherein when the average amplitude is smaller than the preset amplitude, when the braking is determined to be finished,
and when the average amplitude is larger than or equal to the preset amplitude, determining that the braking is not finished.
8. The detection method according to claim 2 or 7, wherein the method of determining whether braking is ended further comprises:
obtaining the time interval of the stator voltage curve between the last collected characteristic point and the adjacent characteristic point; and
determining whether the time interval is greater than a preset time,
wherein when the time interval is greater than a preset time, it is determined that braking is finished,
and when the time interval is less than or equal to the preset time, determining that the braking is not finished.
9. The detection method according to claim 1, wherein the braking distance of the working device is calculated according to the number of the characteristic points, rated parameters of the motor and rated parameters of the working device, and the formula for calculating the braking distance is as follows:
Wherein S represents a braking distance, k represents a characteristic coefficient, N represents the number of the characteristic points, vhRepresenting the rated operating speed of the operating device, p representing the number of pole pairs of the motor, nNThe speed-reducing device is characterized by comprising a motor, a speed reducer, a pulley, a speed reducer and a pulley.
10. A detection device for detecting the braking distance of a working device in a motor system, wherein the motor system comprises a motor, a brake and the working device, the motor is used for driving the working device, and the brake is used for braking the working device, and the detection device comprises:
the sampler is used for sampling and processing the stator voltage to obtain a sampling voltage; and
and the microprocessor is connected to the sampler and used for obtaining a stator voltage curve from the beginning of the braking process to the end of braking according to the sampling voltage and obtaining the braking distance according to the number of characteristic points of the stator voltage curve.
11. The detection device according to claim 10, wherein the microprocessor comprises:
the characteristic point detection unit is connected to the sampler and used for receiving the sampling voltage and judging whether the voltage value of the sampling voltage is equal to the voltage value of the characteristic point or not;
the characteristic point number counting unit is connected to the characteristic point detecting unit and used for updating the number of the characteristic points of the sampling voltage according to the judgment result of the characteristic point detecting unit;
the braking end judging unit is connected to the characteristic point number counting unit and the characteristic point detecting unit and is used for judging whether braking is ended or not; and
a braking distance calculating unit connected to the characteristic point number counting unit and the braking end judging unit for obtaining the braking distance according to the number of the characteristic points,
when the braking end judging unit judges that braking is ended, the sampler stops sampling the stator voltage, and the braking distance calculating unit receives the number of the characteristic points and obtains the braking distance.
12. The detection apparatus of claim 10, wherein the sampler comprises:
the voltage signal sampling module is used for sampling the stator voltage to obtain a first voltage;
the gain module is used for amplifying the first voltage to obtain a second voltage; and
and the signal conditioning module is used for conditioning the second voltage to obtain the sampling voltage.
13. The detection device of claim 12, wherein the microprocessor further comprises: a gain selection unit, the input end of the gain selection unit is connected to the signal conditioning module, the output end is connected to the gain module,
the gain selection unit is used for generating a gain selection signal according to the sampling voltage and transmitting the gain selection signal to the gain module so as to control the gain multiple of the gain module.
Technical Field
The invention relates to the technical field of brakes, in particular to a method and a device for detecting a braking distance.
Background
A brake is a device having a function of decelerating, stopping, or maintaining a stopped state of a moving member (or a moving machine), and is widely used in industrial equipment such as a crane, an elevator, and a construction hoist. The performance state of the brake directly influences the running safety of the equipment, and the measurement of the braking distance has important significance for evaluating the performance of the brake, guaranteeing the running safety of the equipment, preventing safety accidents and the like.
Currently, the braking distance measuring methods are mainly divided into two categories: one is direct measurement and the other is indirect measurement. The direct measurement method measures the positions of the equipment at the beginning and the end of braking by using various detection instruments (such as a measuring ruler, a laser range finder and an ultrasonic range finder), and obtains the braking distance by calculating the difference value of the beginning position and the end position; the indirect measurement method measures the angular displacement of a rotating part such as a motor shaft, a transmission shaft or a brake wheel during braking by using various sensors (such as an encoder, a hall sensor for measuring a rotation angle and the like), and calculates the braking distance according to the relationship between the angular displacement and the displacement of the running direction of the equipment. The direct measurement method is mainly suitable for off-line detection because a special detection instrument is needed and position reading is usually manually recorded; the indirect measurement method adopts a sensor to obtain the rotary angular displacement in the braking process in real time on line, and therefore, the method can be suitable for on-line detection. The online detection of the braking distance has important values for guaranteeing the running safety of equipment in real time, finding the fault of a braking system in time, avoiding the occurrence of safety accidents and the like.
However, the existing online detection method for the braking distance mainly depends on sensor detection, and an encoder or a hall sensor needs to be installed at the shaft end of a motor or a low-speed shaft end of equipment or a brake wheel, so that the problems of complex installation and debugging, high implementation cost, difficulty in later maintenance and the like exist, and the method has great limitation in practical application and popularization. Therefore, a simpler real-time online detection method for the braking distance is sought, and is one of the technical problems to be solved urgently in the industry.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method and an apparatus for detecting a braking distance, wherein the braking distance is obtained according to a stator voltage curve, so as to realize real-time online measurement of the braking distance.
According to a first aspect of the present invention, there is provided a braking distance detecting method for detecting a braking distance of a working device in a motor system, the motor system including a motor for driving the working device, a brake for braking the working device, and the working device, the detecting method including, after detecting a power failure of the motor: obtaining a stator voltage curve from the beginning of the braking process to the end of the braking; and obtaining the braking distance according to the number of the characteristic points of the stator voltage curve.
Preferably, the method of obtaining the stator voltage curve comprises the following steps performed repeatedly: obtaining a sampling voltage; obtaining the number of the characteristic points of the sampling voltage; and judging whether the braking is finished or not, wherein when the braking is judged to be finished, the acquisition of the sampling voltage is stopped.
Preferably, the stator voltage curve has a plurality of characteristic points, and a phase difference between two adjacent characteristic points is a predetermined value.
Preferably, the feature points are zero points, peak points or intermediate points, and the number of the feature points is the number of the zero points, the peak points or the intermediate points.
Preferably, the method of obtaining the sampling voltage includes: sampling the stator voltage to obtain a first voltage; amplifying the first voltage to obtain a second voltage; conditioning the second voltage to obtain the sampled voltage.
Preferably, the method for obtaining the number of the feature points includes: after the sampling voltage is obtained, judging whether the voltage value of the sampling voltage is equal to the voltage value of the characteristic point or not, if the voltage value of the sampling voltage is equal to the voltage value of the characteristic point, updating the number of the characteristic points, and if the voltage value of the sampling voltage is not equal to the voltage value of the characteristic point, not updating the number of the characteristic points, wherein the updated number of the characteristic points is equal to the number of the characteristic points before updating plus one.
Preferably, the method of determining whether braking is finished includes: obtaining the average amplitude of the stator voltage curve between the last collected characteristic point and the adjacent characteristic point; and judging whether the average amplitude is smaller than a preset amplitude or not, wherein when the average amplitude is smaller than the preset amplitude, the braking is judged to be finished, and when the average amplitude is larger than or equal to the preset amplitude, the braking is judged not to be finished.
Preferably, the method of determining whether braking is finished further includes: obtaining the time interval of the stator voltage curve between the last collected characteristic point and the adjacent characteristic point; and judging whether the time interval is greater than preset time or not, wherein when the time interval is greater than the preset time, the braking is judged to be finished, and when the time interval is less than or equal to the preset time, the braking is judged to be not finished.
Preferably, the braking distance of the working device is calculated according to the number of the characteristic points, the rated parameter of the motor and the rated parameter of the working device, and the formula for calculating the braking distance is as follows:
orWherein S represents a braking distance, k represents a characteristic coefficient, N represents the number of the characteristic points, vhRepresenting the rated operating speed of the operating device, p representing the number of pole pairs of the motor, nNThe rated rotation speed of the motor is shown, D is the diameter of the winding drum, i is the reduction ratio, and beta is the multiplying power of the pulley.According to a second aspect of the present invention, there is provided a detection device for detecting a braking distance of a working device in a motor system, the motor system including a motor for driving the working device, a brake for braking the working device, and the working device, the detection device comprising: the sampler is used for sampling and processing the stator voltage to obtain a sampling voltage; and the microprocessor is connected to the sampler and used for obtaining a stator voltage curve from the beginning of the braking process to the end of braking according to the sampling voltage and obtaining the braking distance according to the number of characteristic points of the stator voltage curve.
Preferably, the microprocessor comprises: the characteristic point detection unit is connected to the sampler and used for receiving the sampling voltage and judging whether the voltage value of the sampling voltage is equal to the voltage value of the characteristic point or not; the characteristic point number counting unit is connected to the characteristic point detecting unit and used for updating the number of the characteristic points of the sampling voltage according to the judgment result of the characteristic point detecting unit; the braking end judging unit is connected to the characteristic point number counting unit and the characteristic point detecting unit and is used for judging whether braking is ended or not; and a braking distance calculation unit connected to the feature point number statistics unit and the braking end judgment unit and configured to obtain the braking distance according to the number of feature points, wherein when the braking end judgment unit judges that braking is ended, the sampler stops sampling the stator voltage, and the braking distance calculation unit receives the number of feature points and obtains the braking distance.
Preferably, the sampler includes: the voltage signal sampling module is used for sampling the stator voltage to obtain a first voltage; the gain module is used for amplifying the first voltage to obtain a second voltage; and the signal conditioning module is used for conditioning the second voltage to obtain the sampling voltage.
Preferably, the microprocessor further comprises: the input end of the gain selection unit is connected to the signal conditioning module, and the output end of the gain selection unit is connected to the gain module, wherein the gain selection unit is used for generating a gain selection signal according to the sampling voltage and transmitting the gain selection signal to the gain module so as to control the gain multiple of the gain module.
According to the detection method and device for the braking distance, the braking distance of the working device is calculated by collecting the stator voltage curve, and the method and device are suitable for real-time online measurement of the braking distance; furthermore, the braking distance can be obtained only by collecting the voltage of the motor stator and analyzing, calculating and processing the voltage, no additional sensor and other devices are needed, and the cost is low; furthermore, the detection device is directly connected to the stator wiring end, so that the detection device has the advantages of simplicity in installation, convenience in wiring, convenience in maintenance and the like, and has good application and popularization values.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:
FIG. 1a shows a schematic view of a detection system according to an embodiment of the invention;
figure 1b shows a schematic view of an electrical machine according to an embodiment of the invention;
fig. 2a and 2b show stator voltage curves, respectively, according to an embodiment of the invention;
FIG. 3a shows a flow chart of a detection method according to a first embodiment of the invention;
FIG. 3b shows a flow chart of a detection method according to a second embodiment of the invention;
FIG. 4 shows a schematic view of a detection apparatus according to an embodiment of the invention;
FIG. 5 illustrates a schematic diagram of a voltage signal sampling module according to an embodiment of the invention;
FIGS. 6a and 6b show a schematic and a schematic diagram, respectively, of a gain module according to an embodiment of the invention;
FIG. 7 shows a schematic diagram of a signal conditioning module according to an embodiment of the invention;
FIG. 8 shows a schematic diagram of a microprocessor according to an embodiment of the invention;
fig. 9 shows a waveform diagram of a detection apparatus according to an embodiment of the present invention.
List of reference numerals
100 motor
110 stator
111 stator winding
112 stator winding terminal
120 rotor
121 rotor core
122 rotor winding/bar
123 shaft
130 power supply
140 outer casing
200 detection device
210 power supply module
220 voltage signal sampling module
220a, 220b, 220c sampling circuit
230 gain module
230a, 230b, 230c gain circuit
231 first-stage amplifying circuit
232 multiple-way switch
233 two-stage amplifying circuit
240 signal conditioning module
240a, 240b, 240c conditioning circuit
250 microprocessor
251 characteristic point detection unit
252 number of feature points statistical unit
253 brake end determination unit
254 braking distance calculation unit
255 gain selection unit
260 sampler
300 working device
310 speed reducer
320 reel
400 brake
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.
FIGS. 1a and 1b show schematic views of a detection system and a motor, respectively, according to an embodiment of the invention; fig. 2a and 2b show stator voltage curves, respectively, according to an embodiment of the invention.
As shown in fig. 1a, the sensing system includes a
The
Fig. 1b shows a cross-sectional view of the
Taking the
The
An air gap is formed between the
It should be understood that the structure of the motor is schematically illustrated by taking the
When the
During braking after the
In this embodiment, the stator winding 111 of the
The specific working principle of the
when the power supply voltage of the
in equation (1): u shapes1Represents a first power-off residual voltage of the stator winding 111; lambda [ alpha ]m1Represents the magnitude of the flux linkage between the
When the induced current in the
in equation (2): u shapes2Represents a second power-off residual voltage of the
As can be seen from the equations (1) and (2), when the
In other embodiments, as shown in equations (1) and (2), when the
In other embodiments, the power outage residual voltage Ua stator voltage curve has a plurality of characteristic points, which include a plurality of intermediate points, as shown by the first intermediate points or the second intermediate points in fig. 2a, taking the first intermediate points as an example, the spatial electrical angle θ of the
In other embodiments, the stator voltage curve of the residual voltage Ua has a plurality of characteristic points, wherein the plurality of characteristic points includes a plurality of intermediate points, such as a first intermediate point and a second intermediate point shown in fig. 2a, and a peak point or a zero point is located between adjacent first intermediate points and second intermediate points, so that adjacent first intermediate points and second intermediate points form a pair of intermediate points, and the spatial electrical angles θ between two adjacent pairs of intermediate points are different by pi. In this embodiment, for example, the first collected power failure residual voltage is used as a first feature point, a ratio between the first feature point and the first peak point is calculated, the ratio is set as a predetermined ratio, the predetermined ratio ranges from 0 to 1, when the peak point and a point where the ratio to the peak point is equal to the predetermined ratio are detected again, the point is a second feature point, and due to voltage amplitude attenuation, the peak point needs to be continuously updated in subsequent detection, and so on, a plurality of feature points from the beginning of the braking process to the end of braking can be obtained. The extraction method of the characteristic points is suitable for non-real-time detection of the power-off residual voltage.
It should be understood that the present application is not limited thereto, and the power outage residual voltage Ua stator voltage curve has a plurality of characteristic points, and the phase difference between two adjacent characteristic points is a predetermined value, so that the
Referring to fig. 2b, in the first power-off period T1, the induced current of the
During the entire braking process, i.e. t, when the
Taking the number of zero points for detecting the power-off residual voltage as an example, it should be noted that the zero point is at the power-off time t0The space electrical angle of the
As can be known from motor theory, the following relationship exists between the spatial electrical angular displacement Δ θ of the
Δθ=pα (3)
in formula (3), α represents the mechanical angular displacement of the rotor of the
The mechanical angular displacement α of the
multiplying the mechanical angular displacement alpha of the
S=ksα (5)
operating displacement k of the working
in the formula (6), vhIs the rated operating speed, n, of the
In an alternative embodiment, ksThe following can also be obtained by calculation using the structural parameters of the working device 300:
in the formula (7), D is a drum diameter, i is a reduction ratio, and β is a pulley magnification.
In summary, by combining equations (4), (5), (6) and (7), an equation for calculating the braking distance using the
the above process obtains the relationship between the braking distance S and the number N of the characteristic points of the stator voltage curve, and as can be seen from the formula (8), the braking distance S of the working
Fig. 3a shows a flow chart of a detection method according to a first embodiment of the invention.
In step S101, it is detected whether the motor is powered off. If the motor has been powered off, executing steps S102 to S103; if the motor is not powered off, the step S101 is continuously executed to detect whether the motor is powered off.
In step S102, a stator voltage curve from the start of the braking process to the end of braking is obtained.
In step S103, the braking distance is obtained from the number of characteristic points of the stator voltage curve. The phase difference between two adjacent characteristic points is a preset value, the characteristic points are zero points, peak points or intermediate points of a stator voltage curve, and the number of the characteristic points is the number of the zero points, the peak points or the intermediate points. Preferably, the characteristic point is a zero point of the stator voltage curve. In the step, the mechanical angular displacement of the rotor is obtained according to the number of the characteristic points of the stator voltage curve so as to obtain the braking distance of the working device.
Fig. 3b shows a flow chart of a detection method according to a second embodiment of the invention.
In step S201, it is detected whether the motor is powered off. If the motor has been powered off, steps S202 to S207 are executed; if the motor is not powered off, the step S201 is continuously executed to detect whether the motor is powered off.
In step S202, a sample voltage of the stator winding is obtained to obtain a stator voltage curve in a period from the start of braking to the execution of step S205. In this step, the power-off residual voltage of the stator winding is voltage-sampled to obtain a sampled voltage, and a stator voltage curve is obtained from the sampled voltage. In one or more embodiments, the amplitude of the power-off residual voltage signal is gradually attenuated as the rotation speed of the motor rotor decreases, and in order to more accurately and reliably measure the number of characteristic points of the power-off residual voltage and improve the signal-to-noise ratio of the power-off residual voltage signal, different gain multiples are selected for the power-off residual voltage signals with different amplitudes, and preferably, the corresponding gain multiples are selected by calculating the amplitude of the power-off residual voltage so as to ensure that the signal has a good signal-to-noise ratio. Therefore, after the voltage sampling is performed on the power-off residual voltage of the stator winding, the obtained sampled voltage is preferably processed accordingly. For example, the method includes the steps of collecting power-off residual voltage of a motor stator, obtaining first voltage according to the power-off residual voltage, amplifying the first voltage to obtain second voltage, conditioning the second voltage to obtain sampling voltage, and obtaining an amplitude change curve of the sampling voltage in a period of time, namely a stator voltage curve of the motor.
In step S203, it is determined whether the sampled voltage is a characteristic point to obtain the number of characteristic points of the stator voltage curve. The phase difference between two adjacent characteristic points is a preset value, the characteristic points are zero points, peak points or intermediate points of a stator voltage curve, and the number of the characteristic points is the number of the zero points, the peak points or the intermediate points. Preferably, the characteristic point is a zero point of the stator voltage curve. In this step, taking the feature point as a zero point as an example, it is determined whether the amplitude of the sampling voltage is zero, and it is assumed that n feature points have been detected when step S203 is executed, where n is a natural number. Judging whether the amplitude of the stator voltage curve is zero, if the amplitude of the stator voltage curve is zero, executing a step S2031, updating the n value in the memory or the counter to n +1, and executing a step S204; if the amplitude of the stator voltage curve is not zero, step S204 is performed.
In step S204, it is determined whether braking is finished. In the step, the average amplitude and/or the time interval between the nth characteristic point and the (n-1) th characteristic point are obtained, whether the obtained average amplitude and/or the obtained time interval between the nth characteristic point and the (n-1) th characteristic point exceed a preset range or not is judged, and if the obtained average amplitude and/or the obtained time interval exceed the preset range, the braking is judged to be finished; and if the preset range is not exceeded, determining that the braking is not finished. If braking is finished, executing step S205; if the braking is not finished, step S202 to step S203 are performed. More specifically, step S204 includes step S2041 and/or step S2042.
In step S2041, determining whether an average amplitude between the nth characteristic point and the (n-1) th characteristic point is smaller than a preset amplitude, wherein when n is 0, determining whether the average amplitude between the nth characteristic point and the power failure start time is smaller than the preset amplitude, if so, determining that the motor has finished braking, the number of the characteristic points is n, and executing step S205; if not, step S2042 is executed.
In step S2042, it is determined whether a time interval between the nth feature point and the (n-1) th feature point is greater than a preset time, wherein when n is 0, it is determined whether the time interval between the nth feature point and the power-off start time is greater than the preset time, if so, it is determined that the motor has finished braking, the number of feature points is n, and step S205 is performed; if the time is not longer than the preset time, the motor is judged not to be braked, and step S202 is executed to continue sampling and conditioning the voltage of the stator winding.
In one or more embodiments, the order of executing step S2041 and step S2042 may be interchanged, that is, step S2042 is executed first, it is determined whether the time interval between the nth characteristic point and the (n-1) th characteristic point is greater than the preset time, if so, it is determined that the motor has finished braking, the number of the characteristic points is n, and step S205 is executed; if the time is not longer than the preset time, judging that the motor does not finish braking, executing a step S2041, and judging whether the average amplitude between the nth characteristic point and the (n-1) th characteristic point is smaller than a preset amplitude; if the amplitude is smaller than the preset amplitude, the motor is judged to be stopped braking, and the number of the characteristic points is n; if the amplitude is not smaller than the preset amplitude, the motor is judged not to be braked, and step S202 is executed to continue sampling and conditioning the voltage of the stator winding.
In one or more embodiments, step S2041 or step S2042 may be omitted. For example, step S204 includes step S2041, determining whether an average amplitude between the nth characteristic point and the (n-1) th characteristic point is smaller than a preset amplitude, wherein when n is 0, determining whether the average amplitude between the nth characteristic point and the power-off start time is smaller than the preset amplitude, if so, determining that the motor has finished braking, the number of the characteristic points is n, and executing step S205; if the amplitude is not smaller than the preset amplitude, executing step S202, and continuing to sample and condition the voltage of the stator winding; or step S204 includes step S2042, determining whether a time interval between the nth feature point and the (n-1) th feature point is greater than a preset time, wherein when n is 0, determining whether the time interval between the nth feature point and the power-off start time is greater than the preset time, if so, determining that the motor has finished braking, the number of the feature points is n, and executing step S205; if the time is not longer than the preset time, the motor is judged not to be braked, and step S202 is executed to continue sampling and conditioning the voltage of the stator winding.
In steps S202 to S204, a stator voltage curve of the sample voltage for a period from the power-off to the braking end and the number of characteristic points of the stator voltage curve are obtained.
In step S205, the braking distance is obtained from the number of characteristic points of the stator voltage curve. In this step, the braking distance of the working device is obtained from the number of characteristic points obtained in steps S202 to S204 and the operating parameter or the rated parameter of the working device, using the relationship between the number N of characteristic points of the stator voltage curve obtained in fig. 1, 2a, and 2b and the braking distance S.
Fig. 4 shows a schematic view of a detection apparatus according to an embodiment of the invention.
As shown in fig. 4, the
The
The
The input terminal of the voltage
The
The
The
In this embodiment, the signal relationship between the modules is illustrated by taking the detection of the three-phase voltage of the stator in the motor M as an example. However, the present application is not limited thereto, and the detection of the braking distance may be implemented by detecting a single-phase voltage or a multi-phase voltage of the stator, or by detecting a line voltage of the stator. For example, the voltage
It should be understood that each functional module in this embodiment may be integrated into one processing module, or each functional module may exist separately, or two or more functional modules may be integrated into one module. The integrated modules described above may be implemented in hardware or software.
Fig. 5 shows a schematic diagram of a voltage signal sampling module according to an embodiment of the invention.
As shown in fig. 5, the voltage
It should be understood that the number of sampling circuits of the voltage
Fig. 6a and 6b show a schematic and a schematic diagram, respectively, of a gain module according to an embodiment of the invention.
As shown in fig. 6a, the
As shown in fig. 6b, the
It should be understood that the number of gain circuits of the
Fig. 7 shows a schematic diagram of a signal conditioning module according to an embodiment of the invention.
As shown in fig. 7, the
It should be understood that the number of conditioning circuits of the
FIG. 8 shows a schematic diagram of a microprocessor according to an embodiment of the invention.
As shown in fig. 8, the
The characteristic point detecting unit 251 receives the sampling voltage, taking the motor as a three-phase motor as an example, the characteristic point detecting unit 251 receives the sampling voltage Ua3, the sampling voltage Ub3 and the sampling voltage Uc3 to obtain a stator voltage curve, and detects a characteristic point of the stator voltage curve. In this embodiment, the phase difference between two adjacent characteristic points is a predetermined value, and the characteristic point is a zero point, a peak point, or an intermediate point of the stator voltage curve. Preferably, the characteristic point is a zero point of the stator voltage curve.
The feature point number counting unit 252 is connected to the feature point detecting unit 251, and configured to count the number of feature points, where after the feature point detecting unit 251 detects a feature point of the stator voltage curve, the number n of feature points stored by the feature point number counting unit 252 is updated to n +1, and the number of feature points and the stator voltage curve are transmitted to the braking end determining unit 253; when the feature point detecting unit 251 does not detect the feature point of the stator voltage curve, the number n of feature points stored in the feature point number counting unit 252 is not changed, and the number n of feature points and the stator voltage curve are transmitted to the brake end determining unit 253.
The braking end judging unit 253 is connected to the feature point number counting unit 252 and the feature point detecting unit 251, and is configured to judge whether braking is ended according to an average amplitude and a time interval of a stator voltage curve between an nth feature point and an n-1 st feature point, where when it is judged that braking is not ended, the sampler continues to collect power-off residual voltage of the stator and generates sampling voltage; when it is determined that braking is completed, a signal indicating the number of feature points is transmitted to braking distance calculation section 254.
The braking distance calculating unit 254 is connected to the braking end judging unit 253 and the feature point number counting unit 252, and after receiving the signal representing the number of the feature points, the braking distance calculating unit 254 uses a formula according to the number of the feature points and the prestored working parameters or rated parameters of the working device
OrAnd calculating to obtain a braking distance, and finishing the measurement of the braking distance.The gain selection unit 255 generates a gain selection signal SetGain _ a, a gain selection signal SetGain _ B, a gain selection signal SetGain _ C, and a gain enable signal SetGain _ EN according to the magnitudes of the sampling voltage Ua3, the sampling voltage Ub3, and the sampling voltage Uc3 to adjust the gain multiple of the gain block.
It should be understood that each functional unit in this embodiment may be integrated into one processing unit, each unit may exist separately, or two or more units may be integrated into one unit. The integrated unit may be implemented in the form of hardware or software.
Fig. 9 shows a waveform diagram of a detection apparatus according to an embodiment of the present invention.
As shown in fig. 9, from the beginning of the power failure of the motor, the detection device starts to collect the power failure residual voltage of the stator winding of the motor, detects the characteristic point of the voltage curve of the power failure residual voltage stator, and stops collecting the power failure residual voltage until the braking end judgment unit judges that the braking is finished. In this embodiment, t is the power cut from the motor 1000T from time start to brake end when
The method and the device for detecting the braking distance only need to acquire the voltage signal of the motor stator winding, do not need to install and debug a sensor on user equipment, and compared with the existing methods based on laser ranging, ultrasonic ranging and encoders, the method and the device have the advantages of being simple to install, convenient to wire, low in implementation cost, free of maintenance and the like, are more suitable for real-time online measurement of the braking distance, and have good application and popularization values. In addition, the method and the device can also be applied to the online measurement of the braking distance in the fields of various industrial devices such as elevators, lifting machinery, amusement facilities, electric vehicles and the like, and have wide application prospect.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
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