Motor insulation automatic detection device and method and motor operation control system

Abstract

The application discloses a motor insulation automatic detection device and method and a motor operation control system. The device is used for connecting a motor and a frequency converter. The device comprises a detection circuit unit, an AD sampling unit and an MCU unit. The detection circuit unit is connected with any phase electricity of the motor and a motor shell. The AD sampling unit is connected with the detection circuit unit and the MCU unit. The AD sampling unit is used for acquiring voltage data at a sampling resistor in the detection circuit unit and transmitting the voltage data to the MCU unit for calculation. The MCU unit calculates a motor insulation resistance value according to voltage data of a sampling point and a resistance value of the sampling resistor. The device can automatically detect the insulation of the motor. The motor insulation resistance value can be calculated according to the resistance value of the sampling resistor and the voltage of the sampling point. The control strategy of the motor can be optimized based on the motor insulation resistance value. The safe operation of the motor is facilitated, and the service life of the motor is prolonged.

Description

Technical Field

[0001] This invention relates to the field of motor measurement and control technology, and in particular to an automatic motor insulation detection device, method, and motor operation control system. Background Technology

[0002] In industries such as hoisting, metallurgy, and mining, motors operate in harsh environments with high humidity and moisture, and the vibrations during production often threaten their insulation. Moisture damages the insulation, leading to inter-turn short circuits and changes in the motor's performance parameters. Maintenance is difficult in these challenging environments, and continued full-load operation can easily cause damage, seriously threatening the safety of workers.

[0003] Industries such as hoisting, metallurgy, and mining typically operate underground or in high-temperature environments, making motor maintenance difficult. They generally rely on devices such as contactors, circuit breakers, or frequency converters to protect the motor equipment. (See attached image) Figure 1 (As shown). However, currently there is no dynamic adjustment of the motor's operating conditions based on changes in the motor's insulation performance. After a long period of operation, the insulation of the motor's coils will change to some extent. If the motor continues to operate according to the original parameters, it will at least reduce the motor's service life, and at worst, cause direct damage to the motor.

[0004] Therefore, how to perform insulation testing on motors and then optimize motor control strategies based on the motor insulation resistance value to achieve safe operation and extend the service life of motors has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of the above-mentioned technical problems, the present invention provides an automatic motor insulation detection device, method and motor operation control system. The device can automatically detect the insulation of the motor. By collecting the voltage data at the sampling resistor in the detection circuit unit, the insulation resistance value of the motor can be calculated. Then, the control strategy of the motor can be optimized based on the insulation resistance value, which facilitates the safe operation of the motor and helps to extend the service life of the motor.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide an automatic motor insulation detection device, the device comprising: a detection circuit unit, an AD sampling unit, and an MCU unit; wherein...

[0008] The detection circuit unit is connected to any phase of the motor and the motor housing, respectively;

[0009] The AD sampling unit is connected to the detection circuit unit and the MCU unit respectively, and is used to acquire the voltage data at the sampling resistor in the detection circuit unit and transmit the voltage data to the MCU unit for calculation and processing.

[0010] The MCU unit calculates the motor insulation resistance value based on the voltage data at the sampling resistor and the resistance value of the sampling resistor.

[0011] Furthermore, the device also includes a display unit connected to the MCU unit, used to display the voltage data and the motor insulation resistance value calculated and processed by the MCU unit.

[0012] Furthermore, the MCU unit is equipped with a communication module, and the MCU unit uploads the calculated motor insulation resistance value to the frequency converter for judgment and processing through the communication module.

[0013] Furthermore, the detection circuit unit includes at least: resistors R1 to R4, transformer T1, diodes D1 to D5, transistors Q1 and Q2, capacitors C1 to C4, and varistor RV1;

[0014] One end of resistor R1 is connected to the input terminal of the power supply and one end of the primary coil of transformer T1, and the other end of resistor R1 is connected to the negative terminal of diode D1 and one end of the secondary coil of transformer T1; the positive terminal of diode D1 is connected to one end of resistor R2, and the other end of resistor R2 is grounded.

[0015] The other end of the secondary coil of transformer T1 is connected to the base of transistor Q1 and the collector of transistor Q2, respectively; the collector of transistor Q1 is connected to the other end of the primary coil of transformer T1, one end of varistor RV1, the positive terminal of diode D3, and one end of capacitor C2, respectively; the emitters of transistors Q1 and Q2 are connected to one end of resistor R4, respectively; one end of capacitor C1 is connected to the base of transistor Q2 and the negative terminal of diode D2, respectively; the other end of capacitor C1 is grounded; the positive terminal of diode D2 is connected to the other end of varistor RV1.

[0016] Resistor R4 is used as a sampling resistor. The other end of resistor R4 is connected to one end of capacitor C4 and the motor housing. The other end of capacitor C4 is connected to one end of capacitor C3, the negative terminal of diode D3, and the positive terminal of diode D4. The negative terminal of diode D4 is connected to the other end of capacitor C2 and the positive terminal of diode D5. The negative terminal of diode D5 is connected to one end of resistor R3 and the other end of capacitor C3. Resistor R3 is used as a sampling resistor. The other end of resistor R3 is connected to any phase of the motor.

[0017] Furthermore, the display unit is a digital display screen or a liquid crystal display screen.

[0018] Furthermore, the communication module comprises any one or more of the following: a WIFI module, a public mobile communication network communication module, a Bluetooth module, and a near-field communication module.

[0019] Secondly, embodiments of the present invention also provide an automatic method for detecting motor insulation, which uses the automatic motor insulation detection device described above to perform automatic motor insulation detection. The method includes the following steps:

[0020] S1. Obtain the voltage data at the sampling resistor;

[0021] S2. The motor insulation resistance value is calculated based on the voltage data at the sampling resistor and the resistance value of the sampling resistor.

[0022] Furthermore, the method also includes:

[0023] S3. The motor insulation resistance value is sent to the frequency converter for judgment. When the motor insulation resistance value is greater than or equal to the preset resistance value, the frequency converter adaptively adjusts the motor's operating parameters according to the motor insulation resistance value. When the motor insulation resistance value is less than the preset resistance value, the frequency converter issues an alarm to notify maintenance personnel to check or replace the motor.

[0024] Furthermore, in step 2, the formula for calculating the motor insulation resistance is:

[0025]

[0026] In the formula, Rx is the motor insulation resistance, U1 is the voltage value at the sampling point of sampling resistor R3, Ub is the voltage value at the sampling point of sampling resistor R4, and R3 and R4 are the resistance values ​​of sampling resistors R3 and R4, respectively.

[0027] Thirdly, embodiments of the present invention also provide a motor operation control system, the system comprising: a frequency converter, a motor, and the automatic motor insulation detection device described in the above embodiments;

[0028] The frequency converter is connected to the motor control system, and the automatic motor insulation detection device is connected to both the frequency converter and the motor.

[0029] The automatic motor insulation detection device is used to perform insulation detection on the motor to obtain the motor insulation resistance value, and send the motor insulation resistance value to the frequency converter. The frequency converter adaptively adjusts the operating parameters of the motor according to the motor insulation resistance value to control the operation of the motor.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention can automatically detect the insulation of a motor. By collecting voltage data at the sampling resistor in the detection circuit unit, the insulation resistance of the motor can be calculated. Based on the insulation resistance, the control strategy of the motor can be optimized, which facilitates the safe operation of the motor and helps to extend the service life of the motor. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the working principle of a motor in the prior art provided in the embodiments of the present invention;

[0033] Figure 2 A block diagram illustrating the operating principle of the automatic motor insulation detection device provided in this embodiment of the invention;

[0034] Figure 3 A circuit diagram of the detection circuit unit provided in an embodiment of the present invention;

[0035] Figure 4 A flowchart of an automatic motor insulation detection method provided in an embodiment of the present invention;

[0036] Figure 5 A flowchart illustrating the operation of a motor operation control system provided in an embodiment of the present invention. Detailed Implementation

[0037] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0038] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In industries such as hoisting, metallurgy, and mining, where motors operate underground or at high temperatures, maintenance is difficult. Protection typically relies on the detection functions of contactors, circuit breakers, or frequency converters. Their working principles are as follows: Figure 1 As shown, existing technologies do not dynamically adjust the motor's operating conditions based on changes in motor performance. After prolonged operation, the insulation of the motor's coils will change. If the motor continues to operate according to its original parameters, it will at least reduce the motor's service life, and at worst, cause direct damage to the motor.

[0041] This invention takes into account the impact of changes in motor insulation on motor dynamic parameters. By incorporating the motor parameter—coil insulation impedance—it automatically detects motor insulation during production downtime, thereby obtaining the motor's operating status, promptly identifying changes in motor insulation performance, and adjusting motor operating parameters accordingly. This extends the motor's service life and prevents production shutdowns caused by sudden insulation failure, which could result in significant production losses.

[0042] First embodiment:

[0043] Reference Figure 2 As shown, this embodiment of the invention provides an automatic motor insulation detection device for connecting a motor and a frequency converter. The device includes: a detection circuit unit, an AD sampling unit, and an MCU unit.

[0044] The following is a detailed explanation of each of the above units:

[0045] like Figure 2 As shown, in this embodiment, the detection circuit unit is connected to any phase of the motor and the motor housing respectively; the AD sampling unit is connected to the detection circuit unit and the MCU unit respectively, and is used to obtain the voltage data at the sampling resistor in the detection circuit unit and transmit the voltage data to the MCU unit for calculation; the MCU unit calculates the motor insulation resistance value based on the voltage data and the resistance value of the sampling resistor.

[0046] like Figure 2 As shown, the device also includes a display unit, which can be a digital display screen or an LCD screen. In this embodiment, considering cost and stability, a digital display screen is preferred. The display unit is connected to the MCU unit and is used to display the voltage data and motor insulation resistance value calculated and processed by the MCU unit.

[0047] In this embodiment, a communication module is integrated on the MCU unit. The MCU unit uploads the calculated motor insulation resistance value to the frequency converter for judgment and processing through the communication module. The MCU unit and the frequency converter can use wired communication or wireless communication. When wireless communication is used, the communication module can be composed of any one or more of the following: WIFI module, public mobile communication network communication module, Bluetooth module, and near field communication module.

[0048] Furthermore, the operating characteristics of motors place extremely high demands on the insulation of the coils; generally, the insulation resistance of a motor is required to be greater than 400KΩ. When measuring insulation resistance using Ohm's law, only a sufficiently large applied voltage can measure the current flowing through the insulator. Therefore, the voltage applied to the motor insulator is approximately 1KV. This invention designs a motor insulation monitoring circuit (i.e., the detection circuit unit in this device) that calculates the motor insulation resistance by detecting the voltage across the motor insulator. The circuit of the detection circuit unit is as follows: Figure 3 As shown;

[0049] like Figure 3 As shown, in this embodiment, the detection circuit unit mainly includes: resistors R1 to R4, transformer T1, diodes D1 to D5, transistors Q1 and Q2, capacitors C1 to C4, and varistor RV1;

[0050] One end of resistor R1 is connected to the input terminal of the power supply and one end of the primary coil of transformer T1, and the other end of resistor R1 is connected to the negative terminal of diode D1 and one end of the secondary coil of transformer T1; the positive terminal of diode D1 is connected to one end of resistor R2, and the other end of resistor R2 is grounded.

[0051] The other end of the secondary coil of transformer T1 is connected to the base of transistor Q1 and the collector of transistor Q2, respectively; the collector of transistor Q1 is connected to the other end of the primary coil of transformer T1, one end of varistor RV1, the positive terminal of diode D3, and one end of capacitor C2, respectively; the emitters of transistors Q1 and Q2 are connected to one end of resistor R4, respectively; one end of capacitor C1 is connected to the base of transistor Q2 and the negative terminal of diode D2, respectively; the other end of capacitor C1 is grounded; the positive terminal of diode D2 is connected to the other end of varistor RV1.

[0052] Resistor R4 is used as a sampling resistor. The other end of resistor R4 is connected to one end of capacitor C4 and the motor housing. The other end of capacitor C4 is connected to one end of capacitor C3, the negative terminal of diode D3, and the positive terminal of diode D4. The negative terminal of diode D4 is connected to the other end of capacitor C2 and the positive terminal of diode D5. The negative terminal of diode D5 is connected to one end of resistor R3 and the other end of capacitor C3. Resistor R3 is also used as a sampling resistor. The other end of resistor R3 is connected to any phase of the motor.

[0053] like Figure 3 As shown, the input voltage Vin of the detection circuit unit is between 9-24V. When the detection circuit unit is working, after the power is turned on, the secondary coil of transformer T1 drives Q1 to conduct, and the primary current gradually increases. When the magnetic core of transformer T1 is saturated, the inductance of the secondary coil decreases and transistor Q1 is turned off. Since the primary current cannot change abruptly, the transformer inductor generates a high voltage to charge capacitor C4 through diode D3. Due to the limitation of the varistor, the voltage of C4 is controlled at about 500V. When Q1 is turned on, capacitor C4 charges capacitor C3 through D4 and D5, and the voltages Ua and Ub reach 1KV. Figure 3 The resistance values ​​of resistors R3 and R4 are known. By detecting the voltages U1 and Ub at the sampling points across resistors R3 and R4 using an AD converter, the insulation resistance value Rx of the motor can be calculated. The calculation formula is shown below:

[0054]

[0055] In the formula, Rx is the motor insulation resistance, U1 is the voltage value at the sampling point of sampling resistor R3, Ub is the voltage value at the sampling point of sampling resistor R4, and R3 and R4 are the resistance values ​​of sampling resistors R3 and R4, respectively.

[0056] like Figure 2 As shown, Figure 3 Ua and Ub are respectively connected to any one phase of the motor and the motor casing. Figure 3 The resistance values ​​of resistors R3 and R4 are known. By sampling U1 and Ub using AD, the motor insulation resistance value Rx between Ua and Ub can be calculated using the above formula.

[0057] As can be seen from the above embodiments, the present invention realizes the insulation detection of the motor by setting up independent motor insulation detection circuits. By collecting the voltage of the voltage sampling point of the bridge circuit, the insulation resistance of the motor can be calculated. The insulation parameters are transmitted to the frequency converter in a communication manner, and then the motor control strategy is optimized based on the resistance value of the motor insulation resistance, which facilitates the safe operation of the motor and greatly extends the service life of the motor.

[0058] Second embodiment:

[0059] likeFigure 4 As shown, this embodiment of the invention also provides an automatic motor insulation detection method, which uses the above-mentioned automatic motor insulation detection device to perform automatic motor insulation detection; the method includes the following steps:

[0060] S1. Obtain the voltage data at the sampling resistor;

[0061] S2. Calculate the motor insulation resistance value based on the voltage data at the sampling resistor and the resistance value of the sampling resistor;

[0062] S3. The motor insulation resistance value is sent to the frequency converter for judgment. When the motor insulation resistance value is greater than or equal to the preset resistance value, the frequency converter adaptively adjusts the motor's operating parameters according to the motor insulation resistance value. When the motor insulation resistance value is less than the preset resistance value, the frequency converter issues an alarm to notify maintenance personnel to check or replace the motor.

[0063] The following is a detailed explanation of each of the above steps:

[0064] In step S1 above, the sampling end of the automatic motor insulation detection device in Example 1 is connected to any phase of the motor and the motor casing, and the voltage data at the sampling resistor is acquired by the AD sampling unit of the automatic motor insulation detection device.

[0065] In step S2 above, the AD sampling unit transmits the voltage data acquired at the sampling resistor to the MCU unit of the automatic motor insulation detection device. The MCU unit then uses the voltage data at the sampling resistor and the resistance value of the sampling resistor to perform a calculation using the formula... The insulation resistance of the motor was calculated.

[0066] In the above formula, Rx is the motor insulation resistance, U1 is the voltage value at the sampling point of sampling resistor R3, Ub is the voltage value of sampling resistor R4, and R3 and R4 are the resistance values ​​of sampling resistors R3 and R4, respectively.

[0067] In step S3 above, the MCU unit of the automatic motor insulation detection device sends the motor insulation resistance value to the frequency converter for judgment. When the motor insulation resistance value is greater than or equal to the preset resistance value, for example, when the motor insulation resistance value changes within the range of 400KΩ and above, the frequency converter adaptively adjusts the motor's operating parameters according to the motor insulation resistance value. When the motor insulation resistance value is less than the preset resistance value (i.e., the motor insulation resistance value is less than 400KΩ), the frequency converter issues an alarm to notify maintenance personnel to check or replace the motor.

[0068] As can be seen from the above embodiments, the automatic motor insulation detection method of the present invention can detect the insulation of the motor, calculate the motor insulation resistance value, and dynamically adjust the motor operating parameters based on the change of the motor insulation resistance value and the normal resistance value. This method is suitable for rapid detection before long-term shutdown, can reduce the workload of motor detection, and shorten the motor insulation detection time.

[0069] Third embodiment:

[0070] like Figure 2 As shown, this embodiment of the invention also provides a motor operation control system, which includes: a frequency converter, a motor, and the aforementioned automatic motor insulation detection device; wherein,

[0071] like Figure 2 As shown, the frequency converter is connected to the motor control unit, and the automatic motor insulation detection device is connected to both the frequency converter and the motor. The automatic motor insulation detection device is used to detect the motor's insulation resistance value and send this value to the frequency converter. The frequency converter can then dynamically optimize the motor's operation based on the motor insulation resistance value, ambient temperature, continuous operating time, and load.

[0072] like Figure 5 As shown, the specific workflow of the aforementioned motor operation control system is as follows: During production downtime, the motor insulation is automatically tested. After testing, the data is automatically uploaded to the frequency converter for judgment, and the test data is compared with the normal value. If the insulation resistance is below the preset value, the data is uploaded to the frequency converter to trigger an alarm and notify maintenance personnel to check and replace the motor. If the motor insulation resistance varies within the allowable range, the data is stored, and the motor's operating parameters are dynamically and adaptively adjusted based on the changes in the actual resistance and the normal resistance to optimize motor operation.

[0073] As can be seen from the above embodiments, the motor operation control system of the present invention is equipped with an automatic motor insulation detection device, which is suitable for rapid insulation detection before the motor is stopped for a long time, reducing the workload of motor detection and shortening the motor insulation detection time. At the same time, the frequency converter dynamically adjusts the motor's operating parameters based on the changes in the motor's insulation resistance value and normal resistance value, controls the motor's operation, ensures the safe operation of the motor, and greatly extends the service life of the motor.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An automatic insulation testing device for motors, characterized in that, This device is used to connect a motor and a frequency converter. The device includes: a detection circuit unit, an AD sampling unit, and an MCU unit; wherein... The detection circuit unit is connected to any phase of the motor and the motor housing respectively; the detection circuit unit includes at least: resistors R1 to R4, transformer T1, diodes D1 to D5, transistors Q1 and Q2, capacitors C1 to C4 and varistor RV1; One end of resistor R1 is connected to the input terminal of the power supply and one end of the primary coil of transformer T1, and the other end of resistor R1 is connected to the negative terminal of diode D1 and one end of the secondary coil of transformer T1; the positive terminal of diode D1 is connected to one end of resistor R2, and the other end of resistor R2 is grounded. The other end of the secondary coil of transformer T1 is connected to the base of transistor Q1 and the collector of transistor Q2, respectively; the collector of transistor Q1 is connected to the other end of the primary coil of transformer T1, one end of varistor RV1, the positive terminal of diode D3, and one end of capacitor C2, respectively; the emitters of transistors Q1 and Q2 are connected to one end of resistor R4, respectively; one end of capacitor C1 is connected to the base of transistor Q2 and the negative terminal of diode D2, respectively; the other end of capacitor C1 is grounded; the positive terminal of diode D2 is connected to the other end of varistor RV1. Resistor R4 is used as a sampling resistor. The other end of resistor R4 is connected to one end of capacitor C4 and the motor housing. The other end of capacitor C4 is connected to one end of capacitor C3, the negative terminal of diode D3, and the positive terminal of diode D4. The negative terminal of diode D4 is connected to the other end of capacitor C2 and the positive terminal of diode D5. The negative terminal of diode D5 is connected to one end of resistor R3 and the other end of capacitor C3. Resistor R3 is used as a sampling resistor. The other end of resistor R3 is connected to any phase of the motor. The AD sampling unit is connected to the detection circuit unit and the MCU unit respectively, and is used to acquire the voltage data at the sampling resistor in the detection circuit unit and transmit the voltage data to the MCU unit for calculation and processing. The MCU unit calculates the motor insulation resistance based on the voltage data at the sampling resistor and the resistance value of the sampling resistor; the formula for calculating the motor insulation resistance is: ； In the formula, Rx is the motor insulation resistance, U1 is the voltage value at the sampling point of sampling resistor R3, Ub is the voltage value at the sampling point of sampling resistor R4, and R3 and R4 are the resistance values ​​of sampling resistors R3 and R4, respectively. The MCU unit is equipped with a communication module, and the MCU unit uploads the calculated motor insulation resistance value to the frequency converter for judgment and processing through the communication module.

2. The automatic motor insulation detection device according to claim 1, characterized in that, The device further includes a display unit connected to the MCU unit, used to display the voltage data and the motor insulation resistance value calculated and processed by the MCU unit.

3. The automatic motor insulation detection device according to claim 2, characterized in that, The display unit is a digital display screen or an LCD display screen.

4. The automatic motor insulation detection device according to claim 1, characterized in that, The communication module consists of one or more of the following: a WIFI module, a public mobile communication network communication module, a Bluetooth module, and a near-field communication module.

5. An automatic method for detecting the insulation of an electric motor, characterized in that, The automatic insulation testing of a motor is performed using the automatic motor insulation testing device as described in any one of claims 1-4, and the method includes the following steps: S1. Obtain the voltage data at the sampling resistor; S2. The motor insulation resistance is calculated based on the voltage data at the sampling resistor and the resistance value of the sampling resistor; the formula for calculating the motor insulation resistance is: ； In the formula, Rx is the motor insulation resistance, U1 is the voltage value at the sampling point of sampling resistor R3, Ub is the voltage value at the sampling point of sampling resistor R4, and R3 and R4 are the resistance values ​​of sampling resistors R3 and R4, respectively. The method also includes: S3. The motor insulation resistance value is sent to the frequency converter for judgment. When the motor insulation resistance value is greater than or equal to the preset resistance value, the frequency converter adaptively adjusts the motor's operating parameters according to the motor insulation resistance value. When the motor insulation resistance value is less than the preset resistance value, the frequency converter issues an alarm to notify maintenance personnel to check or replace the motor.

6. A motor operation control system, characterized in that, The system includes: a frequency converter, a motor, and an automatic motor insulation detection device as described in any one of claims 1-4; The frequency converter is connected to the motor control system, and the automatic motor insulation detection device is connected to both the frequency converter and the motor. The automatic motor insulation detection device is used to perform insulation detection on the motor to obtain the motor insulation resistance value, and send the motor insulation resistance value to the frequency converter. The frequency converter adaptively adjusts the operating parameters of the motor according to the motor insulation resistance value to control the operation of the motor.

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