Brushless direct current motor detection device

Abstract

The utility model belongs to the field of direct current motors, and relates to a brushless direct current motor detection device, a detected motor, a torque sensor and a servo motor are coaxially connected through a coupling tool, a servo control unit is electrically connected with a servo driver, the servo control unit is electrically connected with the torque sensor, and the servo driver is electrically connected with the servo motor; the bus current sampling module comprises a current signal sampling circuit, a current signal conditioning circuit, an AD converter and a first MCU, the first MCU is electrically connected with the AD converter, the AD converter is electrically connected with the current signal conditioning circuit, the current signal conditioning circuit is electrically connected with the current signal sampling circuit, the current signal sampling circuit is electrically connected with the tested motor, and the tested motor is electrically connected with the bus current sampling circuit. And the MCU I and the servo control unit are electrically connected with the upper computer. According to the utility model, bus current waveforms are collected at a high speed, open-phase algorithm analysis is carried out, and various open-phase faults of the motor are synchronously and effectively detected under the traditional load test function.

Description

Technical Field

[0001] The utility model belongs to the technical field of DC motors, and particularly relates to a brushless DC motor detection device. Background Art

[0002] A brushless direct current motor usually consists of a permanent magnet rotor, a stator and a driver. Compared with a traditional brushed DC motor, the brushless DC motor replaces the carbon brush with an electronic commutator. Therefore, a brushless DC motor needs to be equipped with a driver to work properly. In order to pursue a smaller motor volume, most medium and small power brushless DC motors adopt an internal driver scheme, that is, the motor drive board and the motor stator are assembled together by welding, and then the end cover is pressed on the welded drive board by a hydraulic press to completely encapsulate the drive board inside the motor. Once the assembly is completed, it is difficult to detect the electrical characteristics of the three-phase current of the motor itself and the drive bridge arm. And in the welding process before assembly, poor welding between the drive board and the motor stator leads is likely to occur, resulting in a phase loss of the motor. For a motor, phase loss operation may cause a series of problems such as out-of-control speed, noise, and vibration, bringing great potential safety hazards to the product.

[0003] Therefore, after the motor drive board and the stator are welded and assembled with the rotor into a complete machine, it is necessary to detect whether there is a phase loss fault caused by poor welding of the drive board. The currently commonly used detection schemes are as follows: 1. Use machine vision detection to monitor the welding quality of the solder joints between the motor stator pins and the drive board pads through machine vision. 2. Judge by noise or speed. 3. Self-detection of the driver, where the driver self-detects the motor winding current and analyzes the phase loss situation.

[0004] The above detection schemes have the following technical defects: 1. When using machine vision detection, it is difficult to detect the virtual soldering of solder joints with a good outer surface, and the overall price is relatively high. 2. Judging by noise or speed, this scheme does not have universal applicability, and for some motors with good assembly processes and drive strategies, its ability to detect phase loss faults is weak. 3. Self-detection of the driver, this scheme does not have universal applicability, and it is impossible to directly know the internal situation of the driver for low-cost motor drivers such as those for household appliances. Summary of the Utility Model

[0005] In order to solve the above technical problems, the utility model provides a brushless DC motor detection device. The technical scheme adopted by the utility model is as follows:

[0006] Brushless DC motor detection device, including a bus current sampling module and a servo loading system; the servo loading system includes: a servo control unit, a servo motor, a servo driver, a torque sensor and a coupling tooling. The motor under test, the torque sensor and the servo motor are coaxially and fixedly connected in sequence through the coupling tooling. The servo control unit is electrically connected to the servo driver, the servo control unit is electrically connected to the torque sensor, and the servo driver is electrically connected to the servo motor; the bus current sampling module includes: a current signal sampling circuit, a current signal conditioning circuit, an AD converter and MCU 1. MCU 1 is electrically connected to the AD converter, the AD converter is electrically connected to the current signal conditioning circuit, the current signal conditioning circuit is electrically connected to the current signal sampling circuit, the current signal sampling circuit is electrically connected to the motor under test, and the MCU 1 and the servo control unit are electrically connected to the upper computer.

[0007] Preferably, it further includes a high-voltage isolation module located at the current interface of the current signal sampling circuit. The high-voltage isolation module is electrically connected to the current signal sampling circuit and the motor under test respectively.

[0008] Preferably, the coupling tooling includes: a tooling bracket, a motor chuck, a connecting shaft, a coupling 1, a coupling 2 and a shaft sleeve. The servo motor is installed at one end of the tooling bracket. The coupling 2 is coaxially installed between the torque sensor and the servo motor. The coupling 1 is coaxially installed between the torque sensor and the connecting shaft. The connecting shaft is fixedly connected to the motor chuck. The shaft sleeve is movably sleeved on the outer periphery of the connecting shaft. The tooling bracket includes four columns that are concentric with the motor chuck and surround the same circumference on the outer periphery of the motor chuck. The motor under test, the torque sensor and the servo motor are all fixedly installed on the four columns through fixed connectors.

[0009] Preferably, the coupling 1 adopts a cross-slider coupling.

[0010] The beneficial effects of the present utility model:

[0011] The present utility model uses the basic structure of a bus current sampling module + a servo loading system. Under load conditions, by high-speed collecting the bus current waveform and performing a phase-loss algorithm analysis, it realizes the effective detection of various phase-loss faults of the motor synchronously under the traditional load test function.

[0012] The present utility model not only meets the insulation isolation requirements of electrical safety testing, but the newly designed bus current sampling module also replaces the original single-function electrical parameter meter, can be compatible with the measurement of conventional voltage, current, and power, and at the same time performs directional high-speed collection and phase-loss analysis of the bus current of the motor, without increasing the overall test time.

[0013] The utility model can integrate functions such as safety regulation testing, reverse electromotive force testing, load testing, etc. It has comprehensive advantages in terms of compatibility, stability, and accuracy, and has the advantages of low cost, high reliability, and being easy to be designed into an integrated testing system. It can be applied to large-scale testing on the production line, and its high-speed data acquisition ability can extract abnormal spectral components generated by the phase-loss motor on the bus current waveform.

[0014] With a relatively low cost, the utility model can quickly and stably detect the phase-loss fault of the motor only by analyzing the bus current.

[0015] The utility model is developed for production line applications, greatly improving the efficiency of on-line motor testing and preventing the phase-loss motor from flowing out to the greatest extent, which may affect the product quality. Description of the Drawings

[0016] In order to more clearly illustrate the specific implementation manners of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific implementation manners or the prior art. Obviously, the drawings in the following description are some specific implementation manners of the utility model. For those of ordinary skill in the art, without creative efforts, other drawings within the protection scope of this application can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic structural principle diagram of the brushless DC motor detection device according to the embodiment of the utility model;

[0018] Figure 2 It is a schematic structural principle diagram of the current acquisition module according to the embodiment of the utility model;

[0019] Among them, 1 is the motor to be tested, 2 is the motor chuck, 3 is the torque sensor, 4 is the servo motor, 5 is the bus current sampling module, 6 is the servo control unit, 7 is the servo driver, 8 is the upper computer, 9 is the connecting shaft, 10 is the first coupling, 11 is the second coupling, and 12 is the bushing. Specific Embodiments

[0020] The following will clearly and completely describe the technical solutions of the utility model in conjunction with the drawings. Obviously, the described embodiments are some, rather than all, of the embodiments of the utility model.

[0021] Such as Figure 1As shown in the figure, a brushless DC motor detection device includes a bus current sampling module 5 for open-phase analysis. The bus current sampling module 5 is electrically connected to the motor under test 1 to achieve data interaction. There is a servo motor 4 that provides load torque, a servo driver 7 and a torque sensor 3 that are correspondingly electrically connected to the servo motor 4. The servo motor 4, the torque sensor 3 and the motor under test 1 are coaxially connected through a special coupling tooling. The servo control unit 6 is electrically connected to the servo driver 7 and the torque sensor 3 respectively. The servo control unit 6 is used for measuring torque and speed signals and performing closed-loop regulation on the servo motor 4. The bus current sampling module 5 and the servo control unit 6 are respectively electrically connected to the upper computer to achieve data interaction.

[0022] The coupling tooling includes: a tooling bracket, a motor chuck 2, a connecting shaft 9, a coupling one 10, a coupling two 11 and a bushing 12. The coupling two 11 is coaxially connected and installed between the torque sensor 3 and the servo motor 4. The coupling one 10 is coaxially connected and installed between the torque sensor 3 and the connecting shaft 9. The connecting shaft 9 is fixedly connected to the motor chuck 2. The bushing 12 is movably sleeved on the outer periphery of the connecting shaft 9. The tooling bracket includes four columns surrounding the outer periphery of the motor chuck 2. The circumference formed by the four columns is concentric with the motor chuck 2. The motor under test 1, the torque sensor 3 and the servo motor 4 are all fixedly installed on the four columns through fixed connectors. The tooling bracket is used for fixedly installing the servo motor 4, the torque sensor 3 and the motor under test 1, while ensuring their concentric coaxial connection, quick clamping, and insulating the motor under test 1 from other parts. The coupling tooling is an automatic clamping device based on the collet principle and is a non-standard self-made part. The pneumatic mechanism controls the bushing 12 to move downward to loosen the motor chuck 2. After the motor under test 1 is clamped and sleeved on the upper end of the motor chuck 2, the pneumatic mechanism controls the bushing 12 to move upward to tighten the motor chuck 2, realizing the automatic coupling of the motor under test 1 and the torque sensor 3.

[0023] The servo driver 7 is connected to the servo motor 4. When performing open-phase detection, the servo motor 4 is in the load state, the servo driver 7 is set to the torque mode, and the current output by the servo driver 7 acts on the windings of the servo motor 4. Under the control of the servo control unit 6, the servo motor 4 provides the required torque. The servo control unit 6 is used to measure the torque signal provided by the torque sensor 3 and the speed signal provided by the servo driver 7. By receiving the speed and torque parameters set by the host computer, it realizes the speed and torque control modes, and respectively feeds back the current speed and torque to the MCU two of the servo control unit 6. After comparing with the given value output by the DA converter and adjusting through the PI controller, a control signal is output to the servo driver 7 to ensure the accuracy and stability of the torque and speed controlled by the load module. The servo motor 4 is in the load state, simulating the load condition during the normal operation of the brushless DC motor. When the motor has an open-phase fault, there will be detectable abnormal spectral components in its bus current. The servo control unit 6 is a prior art, mainly including: MCU two, DA converter and PI controller, and specifically, the Kangdike ANMC3 (V1.1) servo loading control board can be adopted.

[0024] The servo motor 4 is fixedly installed at one end of the tooling bracket. The rotor shaft of the servo motor 4 is coaxially connected to one end of the torque sensor 3 through the coupling two 11, and outputs the required load torque or speed under the control of the servo driver 7. The torque sensor 3 is also fixedly installed on the tooling bracket. The other end of the torque sensor 3 is connected to one end of the connecting shaft 9 through the coupling one 10. The coupling one 10 uses a "cross-slider type" coupling to achieve insulation. The other end of the connecting shaft 9 is coaxially connected to the measured motor 1 through the motor chuck 2. The function of the torque sensor 3 is torque and speed measurement. It can measure the actual speed of the system main shaft connected to the measured motor 1. The measurement result of the torque sensor 3 is communicated with the host computer 8 through the servo control unit 6, and the measurement result is available for the host computer 8 to query.

[0025] Such as Figure 2As shown in the figure, the bus current sampling module 5 includes a high-voltage isolation module, a current signal sampling circuit, a current signal conditioning circuit, an AD converter, and MCU 1, which are electrically connected in sequence. MCU 1 is electrically connected to the AD converter, the current signal conditioning circuit is electrically connected to the AD converter, the current signal conditioning circuit is electrically connected to the current signal sampling circuit, the current signal sampling circuit is electrically connected to the high-voltage isolation module, and the high-voltage isolation module is electrically connected to the motor under test 1. When the motor under test 1 is subjected to a high-voltage test, the high-voltage isolation module is disconnected, and the current signal sampling circuit and the motor under test 1 are respectively on both sides of the high-voltage isolation module, protecting the current signal sampling circuit from being damaged by the motor under test 1 in the high-voltage state. After the high-voltage test is completed, when performing a phase-loss test under the rated voltage, the high-voltage isolation module is closed, and the current signal sampling circuit and the bus of the motor under test 1 are connected in series to complete normal signal acquisition. An internal built-in motor drive board is encapsulated in the motor under test 1, and there are five leads of VM-GND-VCC-VSP-FG externally. The motor operation requires three common-ground DC power supplies, namely VM-310VDC, Vcc-15V, and VSP-5V, and GND is the common ground wire. Among them, when the power supply bus VM-GND is in the power supply operation, the current interfaces I+ and I- of the current signal sampling circuit are serially connected to the VM and GND circuits, and the bus current signal of the VM circuit can be collected. The high-voltage isolation module is designed with an isolation relay at the interface of the current signal sampling circuit, which can isolate 3 kV high voltage. When the customer makes a primary wiring and conducts an electrical safety test, there is no need to change the wire. The high-voltage isolation here can protect the current signal sampling circuit, and the high-voltage isolation module can isolate 3 kV high voltage.

[0026] The current signal sampling circuit is used for collecting the motor bus current, converting the current signal into a voltage signal, and supplying it to the subsequent current signal conditioning circuit for conditioning.

[0027] The current signal conditioning circuit is used for amplifying and filtering the current signal, so that the processed signal is within the range suitable for AD measurement.

[0028] MCU 1 establishes a communication relationship with the software module of the host computer 8, and is used for receiving the measurement configuration parameters sent by the host computer 8. The bus current sampling module extracts the current signal characteristics of the phase loss through MCU 1 and sends them to the host computer 8 for display processing, qualified judgment and other interface interaction operations. The MCU 1 can use the STM32F407 single-chip microcomputer.

[0029] The host computer 8 can specifically use an industrial computer. The MCU single-chip microcomputer and the host computer 8 are connected through Ethernet and can communicate with each other.

[0030] The bus current sampling module 5 is used to collect the bus current signal of the motor 1 to be measured in real time. The bus current signal successively passes through the current signal sampling circuit and the current signal conditioning circuit. After current sampling and signal conditioning, it is sent to the AD converter end. The AD converter high-speed collects the real-time current value digital signal, and the MCU communicates to query the sampled value digital signal of the AD and records a large number of continuous sampling data. When a phase loss fault occurs, the current waveform in the corresponding phase loss sector of the bus current will show an abnormal depression. Through the spectrum analysis algorithm, various types of phase loss faults can be calculated and identified. The bus current sampling module 5 is responsible for extracting the phase loss characteristics, and the host computer 8 is responsible for determining the qualified range and displaying it on the interface.

[0031] The brushless DC motor detection device according to the embodiment of the present invention can replace the electrical parameter meter. It can measure conventional electrical parameters, and can also perform high-speed current collection and analyze and identify the phase loss fault of the motor. It has the ability of high-voltage isolation and can be compatible with electrical safety tests. Under the original load test station, the phase loss fault can be detected synchronously without adding extra test time.

[0032] In the embodiment of the present invention, the technical features not described in detail are all existing technologies or conventional technical means, and will not be elaborated here.

[0033] Finally, it should be noted that the above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any person skilled in the art within the technical scope disclosed by the present invention can modify the technical solutions recorded in the foregoing embodiments or easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A brushless DC motor detection device, characterized in that: It includes a bus current sampling module and a servo loading system; the servo loading system includes: a servo control unit, a servo motor, a servo driver, a torque sensor and a coupling tooling, the motor to be measured, the torque sensor and the servo motor are coaxially fixedly connected in sequence through the coupling tooling, the servo control unit is electrically connected to the servo driver, the servo control unit is electrically connected to the torque sensor, and the servo driver is electrically connected to the servo motor; the bus current sampling module includes: a current signal sampling circuit, a current signal conditioning circuit, an AD converter and MCU1, MCU1 is electrically connected to the AD converter, the AD converter is electrically connected to the current signal conditioning circuit, the current signal conditioning circuit is electrically connected to the current signal sampling circuit, the current signal sampling circuit is electrically connected to the motor to be measured, and the MCU1 and the servo control unit are electrically connected to the host computer.

2. The brushless DC motor detection device according to claim 1, characterized in that: It also includes a high-voltage isolation module located at the current interface of the current signal sampling circuit, and the high-voltage isolation module is electrically connected to the current signal sampling circuit and the motor under test respectively.

3. The brushless DC motor detection device according to claim 1 or 2, characterized in that: The coupling tooling includes: a tooling bracket, a motor chuck, a connecting shaft, a coupling 1, a coupling 2 and a sleeve. The servo motor is installed at one end of the tooling bracket. The coupling 2 is coaxially installed between the torque sensor and the servo motor. The coupling is coaxially installed between the torque sensor and the connecting shaft. The connecting shaft is fixedly connected to the motor chuck. The sleeve is movably mounted on the outer circumference of the connecting shaft. The tooling bracket includes four columns which are concentric with the motor chuck and are on the same circumference around the outer circumference of the motor chuck. The motor to be tested, the torque sensor and the servo motor are all fixedly installed on the four columns through fixed connecting parts.

4. The brushless DC motor detection device according to claim 3, characterized in that: The coupling 1 adopts a cross slider type coupling.

5. The brushless DC motor detection device according to claim 3, characterized in that: The MCU 1 adopts the STM32F407 single-chip microcomputer, and the host computer adopts an industrial computer.

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