A protection device for an electric machine, a protection control method and a protection controller

Abstract

The application discloses a protection device of an electric machine, a control method and a protection controller, the electric machine is electrically connected with a driving controller, the protection device comprises a protection controller, a cooler and a plurality of sensors, the cooler is communicated with a water cooling loop in the electric machine through a water inlet pipe and a water outlet pipe. The plurality of sensors are respectively used for detecting the water inlet temperature, the water outlet temperature, the cooling water flow, the electric machine temperature and the rotating speed of the electric machine; the protection controller predicts the current state and the temperature at future time of the equipment based on the water inlet temperature, the water outlet temperature, the cooling water flow, the electric machine temperature, the rotating speed, the working voltage and the working current of the electric machine, and timely outputs a protection alarm signal when the obtained prediction value satisfies a fault condition, so that an operator timely takes disposal measures. Since the alarm information represents that the temperature at future time satisfies the fault condition, and not the current temperature has over-temperature, the electric machine winding burning or demagnetization can be avoided through the scheme.

Description

Technical Field

[0001] This application relates to the field of motor technology, and more specifically, to a protection device for a motor, a protection control method thereon, and a protection controller. Background Technology

[0002] The thermal protection of the motor is mainly achieved by pre-embedding a temperature sensor inside the winding, which converts temperature changes into changes in the resistance of a thermal resistor. The controller then calculates the resistance value to obtain the actual temperature of the motor. This temperature is compared with the set temperature to determine over-temperature and output an alarm.

[0003] The biggest drawback of using this method for over-temperature protection is that there is a certain lag time between the temperature rise of the motor windings and the change in the resistance of the temperature sensor. As a result, the fault alarm is also delayed, which may lead to the overheating and burnout of the motor windings or, in the case of a permanent magnet motor, demagnetization. Summary of the Invention

[0004] In view of this, this application provides a protection device for an electric motor, a protection control method and a protection controller, for timely temperature protection of the motor to prevent the motor from burning out the windings or demagnetizing due to overheating.

[0005] To achieve the above objectives, the following solution is proposed:

[0006] A protection device for an electric motor, wherein the motor is electrically connected to a drive controller, the protection device includes a protection controller, a cooler, and multiple sensors, wherein:

[0007] The cooler is connected to the water-cooling circuit inside the motor via an inlet pipe and an outlet pipe.

[0008] The multiple sensors are used to detect the operating status of the motor, obtain and output the inlet water temperature value, outlet water temperature value, and cooling water flow rate value of the cooling water, and are also used to obtain and output the motor temperature value and speed value of the motor.

[0009] The protection controller is connected to the signals of the plurality of sensors respectively, and is used to receive the inlet water temperature value, the outlet water temperature value, the cooling water flow rate value, the motor temperature value and the speed value, and is also used to receive the motor operating voltage value and operating current value from the drive controller;

[0010] The protection controller is used to calculate the inlet water temperature, outlet water temperature, cooling water flow rate, rotational speed, motor temperature, operating voltage, and operating current based on a temperature prediction model to obtain predicted values ​​for future times. When the predicted values ​​meet the fault conditions, the protection alarm signal is output to the drive controller through its alarm signal output terminal. The protection alarm signal is used to control the drive controller to send alarm information to the user.

[0011] Optionally, the plurality of sensors includes a first water temperature sensor, a second water temperature sensor, a flow sensor, a motor temperature sensor, and a speed sensor, wherein:

[0012] The first water temperature sensor is installed on the water inlet pipe to detect the water inlet temperature, obtain and output the water inlet temperature value;

[0013] The second water temperature sensor is installed on the water outlet pipe to detect the water temperature, obtain and output the water temperature value;

[0014] The flow sensor is installed on the inlet pipe or the outlet pipe to detect the flow rate of the cooling water, obtain and output the cooling water flow rate value;

[0015] The motor temperature sensor is installed inside the motor and is used to detect the internal temperature of the motor and output the motor temperature value.

[0016] The speed sensor is installed at the shaft end of the motor to detect the speed of the motor and output the speed value.

[0017] Optionally, the drive controller is a frequency converter.

[0018] A protection control method, applied to the protection device described above, optionally includes the following steps:

[0019] Collect various operating parameters of the motor in its current operating state;

[0020] The various operating parameters are calculated to obtain multiple characteristic values ​​of the motor;

[0021] The multiple feature values ​​are calculated based on a pre-built temperature prediction model to obtain predicted values ​​for future times.

[0022] When the predicted value meets the fault conditions, the protection alarm signal is output.

[0023] Optionally, the current operating state can be a start-up state, braking state, speed regulation state, overcurrent state, or stall state for different loads.

[0024] Optionally, the various operating parameters include some or all of the following: inlet water temperature, outlet water temperature, cooling water flow rate, motor speed, motor temperature, operating voltage, and operating current.

[0025] Optionally, the plurality of characteristic values ​​include the power factor, the energy consumption of the motor, and the heat carried away by the cooling water.

[0026] Optionally, the step of calculating the various operating parameters to obtain multiple characteristic values ​​of the motor includes the following steps:

[0027] Calculate the power factor based on the operating current and the operating voltage;

[0028] The energy consumption is calculated based on the operating current, the operating voltage, and the power factor;

[0029] The amount of heat carried away by the cooling water is calculated based on the inlet water temperature, the outlet water temperature, and the cooling water flow rate.

[0030] Optional steps may also be included:

[0031] Obtain various simulated operating parameters of the motor running on a standard loading test platform under simulated field conditions;

[0032] By substituting the various simulated operating parameters into the pre-constructed heat balance equation, the temperature rise coefficient, speed coefficient, and constant are calculated.

[0033] Substituting the temperature rise coefficient, the rotational speed coefficient, and the constant into the heat balance equation yields the temperature prediction model.

[0034] A protection controller, applied to the protection device as described above, optionally includes at least one processor and a memory connected to the processor, wherein:

[0035] The memory is used to store computer programs or instructions;

[0036] The processor is used to execute the computer program or instructions to enable the protection controller to implement the protection control method as described above.

[0037] As can be seen from the above technical solution, this application discloses a motor protection device and its control method and protection controller. The motor is electrically connected to the drive controller. The protection device includes a protection controller, a cooler, and multiple sensors. The cooler is connected to the water-cooling circuit inside the motor through an inlet pipe and an outlet pipe. The multiple sensors are used to detect the motor's inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, and speed. The protection controller predicts the temperature at a future time based on the motor's inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, speed, operating voltage, and operating current. When the predicted value meets the fault conditions, it outputs a protection alarm signal in a timely manner so that the operator can take timely measures to protect the motor. Since the alarm information represents that the temperature at a future time meets the fault conditions, rather than the current temperature exceeding the limit, this solution can prevent the motor windings from burning out or demagnetizing. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of a protection device according to an embodiment of this application;

[0040] Figure 2 This is a flowchart of a protection control method according to an embodiment of this application;

[0041] Figure 3 This is a flowchart illustrating the method for constructing a temperature prediction model according to an embodiment of this application.

[0042] Figure 4 This is a block diagram of a protection controller according to an embodiment of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0044] Example 1

[0045] Figure 1 This is a schematic diagram of a protection device according to an embodiment of this application.

[0046] This protection device is used to protect the temperature of motor 100, which is driven by drive controller 200, which can be implemented using a frequency converter. The drive controller also contains corresponding sensors that can detect the operating current and voltage of the motor during operation, thereby obtaining the operating current and voltage values.

[0047] like Figure 1 As shown, the protection device provided in this embodiment includes a protection controller 10 connected to the motor signal, multiple sensors 20, and a cooler 30. The protection controller is connected to the multiple sensors and the drive protector signal respectively. The cooler is connected to the water cooling circuit inside the motor through an inlet pipe and an outlet pipe, and the heat inside the motor is removed by water circulation to cool the motor.

[0048] Multiple sensors include a first water temperature sensor 21, a second water temperature sensor 22, a flow sensor 23, a motor temperature sensor (not shown), and a speed sensor 24, which are used to detect the inlet water temperature, outlet water temperature, cooling water flow rate, internal temperature of the motor, and motor speed, respectively.

[0049] The first temperature sensor is installed on the inlet pipe and is connected to the protection controller via a signal line. It is used to detect the inlet water temperature and output the inlet water temperature value to the protection controller. The second water temperature sensor is installed on the outlet pipe and is connected to the protection controller via a signal line. It is used to detect the outlet water temperature and output the outlet water temperature value to the protection controller. The flow sensor is installed on either the inlet or outlet pipe and is connected to the protection controller via a signal line. It is used to detect the cooling water flow rate and output the obtained cooling water flow rate value to the protection controller.

[0050] A motor temperature sensor (not shown) is installed inside the motor to detect the internal temperature of the motor. It is connected to the protection controller via the motor's terminal box and outputs the obtained motor temperature value to the protection controller. A speed sensor is installed at the end of the motor shaft and is connected to the protection controller via a signal line. It is used to detect the motor speed and output the speed value to the protection controller.

[0051] The protection controller is also used to receive the operating voltage and current values ​​of the motor from the drive controller. The protection controller is equipped with an alarm signal output terminal 11, which is connected to the drive controller signal output terminal.

[0052] After receiving multiple operating parameters such as inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, speed, operating voltage, and operating current, the protection controller calculates these parameters based on a temperature prediction model to obtain predicted values ​​for future times. It then judges these predicted values. If the predicted value meets the fault conditions, it outputs a protection alarm signal to the drive controller through the alarm signal output terminal. The protection alarm signal is used to control the drive controller to send alarm information to the user.

[0053] Upon receiving a protection alarm signal, operators can take timely measures, such as pausing startup, reducing operating load, or stopping operation, thereby protecting the motor.

[0054] As can be seen from the above technical solution, this embodiment provides a motor protection device. The motor is electrically connected to the drive controller. The protection device includes a protection controller, a cooler, and multiple sensors. The cooler is connected to the water-cooling circuit inside the motor through an inlet pipe and an outlet pipe. The multiple sensors are used to detect the motor's inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, and speed. The protection controller predicts the future temperature based on the motor's inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, speed, operating voltage, and operating current. When the predicted value meets the fault conditions, it promptly outputs a protection alarm signal so that the operator can take timely measures to protect the motor. Since this alarm information represents that the future temperature meets the fault conditions, rather than the current temperature exceeding the limit, this solution can prevent the motor windings from burning out or demagnetizing.

[0055] The protection alarm signal itself can also be configured to reduce the power output of the drive controller or stop the output of electrical energy, thereby achieving automatic protection of the motor.

[0056] Example 2

[0057] Figure 2 This is a flowchart of a protection control method according to an embodiment of this application.

[0058] like Figure 2 As shown, the protection control method provided in this embodiment is applied to the protection controller of the protection device in the previous embodiment. The protection control method specifically includes the following steps:

[0059] S1. Collect various operating parameters of the motor in its current operating state.

[0060] The current operating status here refers to the operating status for different loads, including starting status, braking status, speed regulation status, overcurrent status, and stall status. The various operating parameters here refer to some or all of the inlet water temperature, outlet water temperature, cooling water flow rate, motor speed, motor temperature, operating voltage, and operating current values ​​collected by multiple sensors in the above embodiments.

[0061] S2. Calculate multiple operating parameters to obtain multiple characteristic values.

[0062] First, the power factor cosΦ is calculated based on the phase difference Φ between the instantaneous values ​​of the operating current and the operating voltage. The calculation process is a common method in this field and will not be described in detail here.

[0063] Then, based on the obtained power factor, the energy consumption E of the motor during time t1-t2 is calculated according to the power factor, operating voltage, and operating current. in .

[0064] E in =∫U*I*cosΦdt

[0065] Where U is the operating voltage and I is the operating current.

[0066] Then, based on the above parameters, calculate the heat E carried away by the cooling water during the time period t1-t2. out .

[0067] E out =Cρq(t2-t1)(T2-T1)

[0068] Where C is the specific heat capacity of water, ρ is the density of water, q is the cooling water flow rate, T2 is the cooling water outlet temperature, and T1 is the cooling water inlet temperature.

[0069] S3. Calculate the predicted value for future times based on the temperature prediction model.

[0070] The temperature prediction model here actually refers to a heat balance equation for a motor constructed based on the law of conservation of energy, except that the coefficients and constants are already defined. The heat balance equation is:

[0071] E in *(1-γ)-E out =K1*Δ t +n*K2+K3

[0072] Where, Δ t γ is the motor temperature rise, γ is the motor efficiency (usually taken as 0.92), K1 is the motor temperature rise coefficient, K2 is the motor speed coefficient, K3 is a constant, and n is the motor speed.

[0073] Given the temperature rise coefficient, speed coefficient, and constant, the aforementioned characteristic values, including energy consumption and heat carried away by cooling water, are substituted into the temperature prediction model to obtain a predicted value for future times. The predicted value is the motor temperature rise here plus the current temperature.

[0074] S4. When the predicted value meets the fault conditions, output a protection alarm signal.

[0075] The predicted value is compared with a preset temperature threshold, which is the highest temperature at which the motor will not burn out or demagnetize. If the predicted value is higher than the temperature threshold, it is determined that the predicted value meets the fault conditions. At this time, a protection alarm signal is output. The protection alarm signal is used to make the motor drive controller send an alarm message to the operator so that the operator can make timely prompts.

[0076] In actual operation, fault conditions can be specified, that is, the predicted value can be determined to meet the fault conditions only when the predicted value is higher than the temperature threshold in three consecutive cycles, thereby avoiding false alarms.

[0077] As can be seen from the above technical solution, this embodiment provides a protection and control method. This method is applied to the motor protection device of the previous embodiment. Specifically, it involves collecting multiple operating parameters of the motor in its current operating state; calculating the multiple operating parameters to obtain multiple characteristic values ​​of the motor; calculating the multiple characteristic values ​​based on a pre-built temperature prediction model to obtain predicted values ​​for future times; and outputting a protection alarm signal when the predicted values ​​meet the fault conditions. Since this alarm information represents that the temperature at a future time meets the fault conditions, rather than the current temperature exceeding the limit, this solution can prevent the motor windings from burning out or demagnetizing.

[0078] In addition, in one specific embodiment of this example, the following steps are also included to obtain a high-temperature prediction model, such as... Figure 3 As shown:

[0079] S31. Obtain various simulated operating parameters of the motor.

[0080] The motor here is placed on a standard loading test platform and made to run under simulated field conditions. Under these conditions, a variety of simulated operating parameters are tested. Since the motor is built based on the motor operating state in Embodiment 1, the various simulated operating parameters include inlet water temperature, outlet water temperature, cooling water flow rate, motor temperature, speed, operating voltage, operating current, and motor temperature rise.

[0081] S32. Calculate the temperature rise coefficient, speed coefficient, and constant based on various simulated operating parameters.

[0082] Specifically, multiple characteristic values ​​are calculated based on the overload simulation operation parameters, and then these values ​​are substituted into the heat balance equation pre-constructed based on the law of conservation of energy. The heat balance equation is as follows:

[0083] E in *(1-γ)-E out =K1*Δ t +n*K2+K3

[0084] Where, Δ t γ is the motor temperature rise, γ is the motor efficiency (usually taken as 0.92), K1 is the motor temperature rise coefficient, K2 is the motor speed coefficient, K3 is a constant, and n is the motor speed.

[0085] Since the motor temperature rise is known, the temperature rise coefficient, speed coefficient, and constant can be obtained through calculation.

[0086] S33. Construct a temperature prediction model.

[0087] Substituting the temperature rise coefficient, rotational speed coefficient, and constant obtained above into the heat balance equation, we obtain the temperature prediction model.

[0088] The various simulation parameters obtained above can be divided into two parts: a training set and a test set. After obtaining the temperature prediction model using the training set, it needs to be tested using the test set. Only when the results obtained by the temperature prediction model differ from the actual measured values ​​by less than a certain value, such as 5%, can it be used in the final temperature prediction model.

[0089] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0090] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of the present invention can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0092] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0093] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0094] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0095] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0096] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A protection device for a motor, wherein the motor is electrically connected to a drive controller, characterized in that, The protection device includes a protection controller, a cooler, and multiple sensors, wherein: The cooler is connected to the water-cooling circuit inside the motor via an inlet pipe and an outlet pipe. The multiple sensors are used to detect the operating status of the motor, obtain and output the inlet water temperature value, outlet water temperature value, and cooling water flow rate value of the cooling water, and are also used to obtain and output the motor temperature value and speed value of the motor. The protection controller is connected to the signals of the plurality of sensors respectively, and is used to receive the inlet water temperature value, the outlet water temperature value, the cooling water flow rate value, the motor temperature value and the speed value, and is also used to receive the motor operating voltage value and operating current value from the drive controller; The protection controller is configured to perform the following operations: Calculate the power factor and energy consumption based on the operating current and the operating voltage; The heat carried away by the cooling water is calculated based on the inlet water temperature, the outlet water temperature, and the cooling water flow rate. Based on the temperature prediction model, the energy consumption, the heat carried away by the cooling water, and the rotational speed are substituted into the heat balance equation: E in *(1- )-E out =K1*Δ t +n*K2+K3, to calculate the predicted value for future times, where E in For energy consumption, For motor efficiency, E out K1 is the heat carried away by the cooling water, and Δ is the temperature rise coefficient. t Let n be the motor temperature rise, K2 be the motor speed, K3 be the speed coefficient, and K3 be a constant. The predicted value is the sum of the current motor temperature and the motor temperature rise. When the predicted value meets the fault conditions, a protection alarm signal is output to the drive controller through its alarm signal output terminal. The protection alarm signal is used to control the drive controller to send alarm information to the user.

2. The protection device as described in claim 1, characterized in that, The plurality of sensors include a first water temperature sensor, a second water temperature sensor, a flow sensor, a motor temperature sensor, and a speed sensor, wherein: The first water temperature sensor is installed on the water inlet pipe to detect the water inlet temperature, obtain and output the water inlet temperature value; The second water temperature sensor is installed on the water outlet pipe to detect the water temperature, obtain and output the water temperature value; The flow sensor is installed on the inlet pipe or the outlet pipe to detect the flow rate of the cooling water, obtain and output the cooling water flow rate value; The motor temperature sensor is installed inside the motor and is used to detect the internal temperature of the motor and output the motor temperature value. The speed sensor is installed at the shaft end of the motor to detect the speed of the motor and output the speed value.

3. The protection device as described in claim 1, characterized in that, The drive controller is a frequency converter.

4. A protection control method, applied to the protection device as described in any one of claims 1 to 3, characterized in that, The protection and control method steps are as follows: Collect various operating parameters of the motor in its current operating state; The various operating parameters are calculated to obtain multiple characteristic values ​​of the motor, including the power factor, the energy consumption of the motor, and the heat carried away by the cooling water. The multiple feature values ​​are calculated based on a pre-built temperature prediction model to obtain predicted values ​​for future times. When the predicted value meets the fault condition, the protection alarm signal will be output. The temperature prediction model is expressed by the following heat balance equation: E in *(1- )-E out =K1*Δ t +n*K2+K3; Where Δt is the motor temperature rise, K1 is the motor efficiency, K2 is the temperature rise coefficient, K3 is a constant, n is the motor speed, and E is the motor efficiency. in For energy consumption, E out The heat carried away by the cooling water.

5. The protection and control method as described in claim 4, characterized in that, The current operating state refers to the start-up state, braking state, speed regulation state, overcurrent state, or stall state for different loads.

6. The protection and control method as described in claim 4, characterized in that, The various operating parameters include some or all of the following: inlet water temperature, outlet water temperature, cooling water flow rate, motor speed, motor temperature, operating voltage, and operating current.

7. The protection and control method as described in claim 6, characterized in that, The calculation of the various operating parameters to obtain multiple characteristic values ​​of the motor includes the following steps: Calculate the power factor based on the operating current and the operating voltage; The energy consumption is calculated based on the operating current, the operating voltage, and the power factor; The amount of heat carried away by the cooling water is calculated based on the inlet water temperature, the outlet water temperature, and the cooling water flow rate.

8. The protection and control method as described in claim 4, characterized in that, It also includes the following steps: Obtain various simulated operating parameters of the motor running on a standard loading test platform under simulated field conditions; By substituting the various simulated operating parameters into the pre-constructed heat balance equation, the temperature rise coefficient, the rotational speed coefficient, and the constant are calculated. Substituting the temperature rise coefficient, the rotational speed coefficient, and the constant into the heat balance equation yields the temperature prediction model.

9. A protection controller, applied to the protection device as described in any one of claims 1 to 3, characterized in that, The protection controller includes at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs or instructions; The processor is used to execute the computer program or instructions to enable the protection controller to implement the protection control method as described in any one of claims 4 to 8.

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