Flat wire motor loss determination method, control module, system and computer program product

Abstract

The embodiment of the invention provides a flat wire motor loss determination method, a control module, a system and a computer program product, and the method achieves the separation of the total loss of a flat wire motor through comparing the total loss and current of two motors which have different winding structures and have the same loss except the copper loss under the same working condition. Total copper loss, direct-current copper loss and alternating-current additional copper loss are divided; on one hand, the copper loss part in the total loss of the flat wire motor can be accurately separated, and on the other hand, the copper loss and the constituent parts of the copper loss can be efficiently determined only through comparison experiments and data processing.

Description

Technical Field

[0001] The present application relates to the technical field of motor loss testing, and in particular to a method for determining flat wire motor loss, a control module, a system and a computer program product. Background Art

[0002] At present, permanent magnet synchronous motors are widely used in industrial applications due to their high efficiency, high power density, and excellent dynamic response characteristics, especially in the fields of electric vehicles and rail transportation. Flat wire windings have the advantages of high slot fill rate, good thermal conductivity, and low vibration and noise. Currently, flat wire permanent magnet synchronous motors have become one of the mainstream winding forms for electric vehicle drive motors.

[0003] However, due to the larger conductor cross-section of the flat wire conductor, accompanied by a more significant skin effect, the AC additional copper loss can reach more than twice the DC copper loss under high-frequency conditions. Accurate calculation, testing and evaluation of the AC additional copper loss are crucial for optimizing the design, suppressing the high-frequency AC additional copper loss and ensuring the safe operation of the motor. However, in the relevant technology, only the total loss of the motor can be determined, and the copper loss of the motor cannot be separated, including the total copper loss, DC copper loss, and AC additional copper loss. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method, control module, system and computer program product for determining the loss of a flat wire motor, so as to achieve the technical effect of efficiently and accurately separating the motor loss.

[0005] In a first aspect, an embodiment of the present application provides a method for determining a flat wire motor loss, the method being applied to a control module of a flat wire motor loss separation system, the system comprising a first motor and a second motor; the control module being communicatively connected to the first motor and the second motor respectively; the first motor being a flat wire winding motor, the second motor having a different winding structure from the first motor, and having the same losses in the total power loss except for copper loss; the method comprising:

[0006] Obtaining a first total power loss and a first current of the first motor under the same operating condition, and obtaining a second total power loss and a second current of the second motor; the operating condition includes a rotation speed, a current amplitude, and a current angle;

[0007] Determine the remaining losses of the first motor except the copper loss based on the second total power loss and the second current;

[0008] determining a total copper loss of the first motor based on the first total power loss and the remaining losses except the copper loss;

[0009] Based on the total copper loss and the first current, a DC copper loss and an AC additional copper loss of the first motor are determined.

[0010] In the above implementation process, under the same working conditions, by comparing the total loss and current of two motors with different winding structures and the same losses except copper loss, the total loss of the flat wire motor is separated, and the total copper loss, DC copper loss, and AC additional copper loss are divided. A second motor with a similar but different winding structure is introduced as a reference. On the one hand, the copper loss in the total loss of the flat wire motor can be accurately separated, and on the other hand, the copper loss and its components can be efficiently determined only through comparative experiments and data processing.

[0011] Further, the determining of the remaining losses of the first motor except the copper loss based on the second total power loss and the second current includes:

[0012] Obtaining the DC resistance of each phase of the second motor and the number of phases of the second motor;

[0013] Determining the copper loss of the second motor based on the DC resistance per phase of the second motor, the number of phases of the second motor, and the second current;

[0014] The remaining losses of the first motor excluding the copper loss are determined based on the second total power loss and the copper loss of the second motor.

[0015] In the above implementation process, by calculating the copper loss of the second motor and inferring the losses of the first motor other than the copper loss based on the result, the difficulty of directly measuring the complex losses of the first motor is avoided and the accuracy of the result is improved.

[0016] Further, determining the DC copper loss and the AC additional copper loss of the first motor based on the total copper loss and the first current includes:

[0017] Obtaining the DC resistance of each phase of the first motor and the number of phases of the first motor;

[0018] Determining the DC copper loss based on the DC resistance per phase of the first motor, the number of phases of the first motor, and the first current;

[0019] The AC additional copper loss is determined based on the total copper loss and the DC copper loss.

[0020] In the above implementation process, the DC copper loss and AC additional copper loss of the motor are further subdivided.

[0021] Further, the system further includes a third motor; the control module is in communication connection with the third motor; the third motor and the first motor have different core connection modes, and the losses other than iron loss in the total power loss are the same; the method further includes:

[0022] determining mechanical losses of the first motor, and determining permanent magnet losses of the first motor;

[0023] Determining a total iron loss of the first motor based on the first total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss;

[0024] Obtaining a third total power loss of the third motor under the same operating condition;

[0025] Determining the iron loss of the third motor based on the third total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss;

[0026] Based on the total iron loss of the first motor and the iron loss of the third motor, the iron loss of the first motor caused by the core connection mode is determined.

[0027] In the above implementation process, the mechanical loss, permanent magnet loss, total iron loss, and iron loss caused by the core connection mode of the first motor are determined, wherein the third motor is introduced as a reference for determining the iron loss caused by the core connection mode.

[0028] Further, the system further includes a fourth motor; the control module is in communication connection with the fourth motor; the fourth motor and the first motor have different rotor structures and the same mechanical loss; and determining the mechanical loss of the first motor includes:

[0029] The mechanical loss of the fourth motor under the same operating condition is obtained, and the mechanical loss of the fourth motor is determined as the mechanical loss of the first motor.

[0030] In the above implementation process, mechanical losses usually include various frictions and resistances inside the motor. For the first motor, accurate measurement of these losses is relatively difficult, while the mechanical loss measurement of the fourth motor is relatively simple. The mechanical loss of the first motor is determined by the mechanical loss of the fourth motor, which improves both measurement accuracy and efficiency.

[0031] Further, determining the permanent magnet loss of the first motor includes:

[0032] Acquiring temperature change information of the first motor under the same operating conditions;

[0033] Based on the temperature change information, a permanent magnet loss of the first motor is determined.

[0034] In the above implementation process, the permanent magnet loss is determined through temperature information.

[0035] Further, the system includes a connected motor under test and a load motor, the motor under test is any one of the first motor, the second motor, the third motor and the fourth motor, and the load motor is any one of the first motor, the second motor and the third motor; and in the same loss determination test, the motor under test and the load motor are selected from different motors; the load motor operates in a speed control mode, and the motor under test operates in a current control mode.

[0036] In the above implementation process, the load motor running in the speed control mode can simulate the load conditions in actual working conditions, so that the measured motor can more accurately reflect its actual loss situation when running in the current control mode.

[0037] A second aspect of an embodiment of the present application provides a control module, wherein the control module includes:

[0038] processor;

[0039] a memory for storing processor-executable instructions;

[0040] Wherein, when the processor calls the executable instruction, any method described in the first aspect is implemented.

[0041] A third aspect of the embodiments of the present application provides a computer program product, wherein the computer program product includes a computer program, and when the computer program is executed by a processor, any method described in the first aspect is implemented.

[0042] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements any of the methods described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A schematic flow chart of a method for determining flat wire motor loss provided in an embodiment of the present application;

[0045] Figure 2 A schematic flow chart of another method for determining flat wire motor loss provided in an embodiment of the present application;

[0046] Figure 3A schematic flow chart of another method for determining flat wire motor loss provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram of the structure of a flat wire motor loss separation system provided in an embodiment of the present application;

[0048] Figure 5 A schematic diagram of a total loss separation process provided in an embodiment of the present application;

[0049] Figure 6 A schematic diagram of a permanent magnet temperature rise curve provided in an embodiment of the present application;

[0050] Figure 7 A hardware structure diagram of a control module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0052] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0053] At present, there are methods for calculating the AC copper loss of flat wire motors using finite element simulation, and the losses under different operating frequencies and current excitations can be solved, and the current density distribution law inside different conductors can be obtained, which provides powerful guidance for improving motor design from aspects such as conductor arrangement, number of layers, stator slot type, slot height, slot width, etc. However, the correctness of theoretical analysis needs to be verified experimentally, and AC loss is usually coupled with DC copper loss, stator and rotor iron loss, etc., and there is currently a lack of methods to separate AC copper loss in experimental tests.

[0054] In response to any of the above-mentioned problems, the present application provides a method for determining the loss of a flat wire motor, referring to Figure 1 , Figure 1 A schematic flow chart of a method for determining flat wire motor losses provided in an embodiment of the present application.

[0055] In this embodiment, the method is applied to a control module of a flat wire motor loss separation system, the system comprising a first motor and a second motor; the control module is respectively connected to the first motor and the second motor in communication; the first motor is a flat wire winding motor, the second motor has a different winding structure from the first motor, and the other losses in the total power loss except copper loss are the same; the method comprises:

[0056] Step S10: obtaining a first total power loss and a first current of the first motor under the same operating condition, and obtaining a second total power loss and a second current of the second motor; the operating condition includes a rotation speed, a current amplitude, and a current angle;

[0057] It should be noted that the control module can be presented in the form of hardware or software, and can include one or more units. This embodiment and the following embodiments illustrate the control module in the form of a combination of a bench and a motor controller. Of course, in addition to this, illustratively, the control mode can also be a host computer.

[0058] The first motor is a motor to be tested for various losses to be determined, and has a flat wire winding structure. A flat wire winding motor is a motor wound with flat wires, and this design is usually used to increase the slot fill rate of the motor, reduce resistance and copper loss. The first motor can be any type of motor using flat wire winding technology, including but not limited to: permanent magnet synchronous motor, induction motor, switched reluctance motor.

[0059] The second motor has a different winding structure from the first motor, but the other losses (such as iron loss, mechanical loss, permanent magnet loss, etc.) in the total power loss are the same except for copper loss. The type selection of the second motor includes but is not limited to: a round wire winding permanent magnet synchronous motor and a Litz wire winding permanent magnet synchronous motor. In this embodiment and the following embodiments, the first motor and the second motor are respectively described by a flat wire winding welded iron core permanent magnet synchronous motor and a Litz wire winding welded iron core permanent magnet synchronous motor. The output torque of the first motor and the second motor under the same working condition is equal, and the mechanical loss, permanent magnet loss, and iron loss under the same working condition are equal.

[0060] It is understandable that different operating conditions correspond to different rotation speeds, current amplitudes, and current angles.

[0061] The speed determines the rotation speed of the motor rotor. In the flat wire motor loss separation experiment, it is necessary to ensure that the first motor and the second motor run at the same speed in order to compare their loss characteristics.

[0062] The current amplitude refers to the magnitude of the current passing through the winding when the motor is running. Under the same operating conditions, the current amplitude of the first motor and the second motor also needs to be consistent to ensure that the losses generated by the current are comparable.

[0063] The current angle (also called the power factor angle) is a measure of the phase difference between the current and the voltage. In a motor, the current angle is closely related to the motor's load characteristics, power factor, etc. In the experiment, keeping the current angle of the first motor and the second motor the same helps to more accurately analyze the losses of the two motors under the same load conditions.

[0064] First, second total power loss: the sum of all losses generated by the motor during operation. Specifically, the total power loss is the input electrical power minus the output mechanical power, where the input electrical power can be measured by a power analyzer, and the output mechanical power is equal to the product of torque and speed, and the torque and speed can be measured by a torque sensor.

[0065] The first and second currents can be effective values ​​of the current, peak values ​​of the current, or currents actually passing through the motor. This embodiment and the following embodiments describe the first and second currents using effective values ​​of the current.

[0066] Step S20: determining the remaining losses of the first motor except the copper loss based on the second total power loss and the second current;

[0067] It should be noted that, in this embodiment, the AC copper loss of the second motor is not considered, and the copper loss of the second motor is equal to its DC copper loss. The copper loss of the second motor can be calculated based on the effective value of the current of the second motor.

[0068] It is understandable that, since the second motor has the same losses as the first motor except for the copper loss, the total power loss of the second motor can be regarded as the copper loss and the remaining losses. The remaining losses of the second motor are obtained by subtracting the copper loss from the total loss of the second motor, which is also the remaining losses of the first motor.

[0069] Step S30: determining the total copper loss of the first motor based on the first total power loss and the remaining losses except the copper loss;

[0070] It is understandable that the total power loss of a motor can usually be decomposed into multiple parts, the most important of which are copper loss (loss caused by current passing through the winding resistance) and other losses except copper loss (including iron loss, mechanical loss, permanent magnet loss, etc.).

[0071] Step S40: determining the DC copper loss and the AC additional copper loss of the first motor based on the total copper loss and the first current.

[0072] It should be noted that DC copper loss refers to the loss caused by the existence of winding resistance when current passes through the motor winding. In DC motors, this loss is the main form of copper loss; in AC motors, DC copper loss is also generated when the current has a DC component (such as DC bias current). However, in many AC motor applications, the main concern is the loss caused by the AC current component.

[0073] AC additional copper loss refers to the additional copper loss in AC motors due to the non-DC characteristics of the current waveform (such as a sine wave). This is mainly due to the instantaneous power loss in the winding resistance when the current changes over time.

[0074] The total copper loss can be decomposed into DC copper loss and AC additional copper loss.

[0075] Specifically, the DC copper loss is calculated based on the first current, and then the AC additional copper loss is obtained by subtracting the DC copper loss from the total copper loss.

[0076] As an example, first, determine the DC component in the first current. This can be obtained by measurement, calculation or experimental calibration. After determining the DC component and the equivalent resistance of the motor winding, use Joule's law to calculate the DC copper loss.

[0077] In this embodiment, by introducing a second motor having a different winding structure from the first motor but having the same losses except for copper loss, the various copper losses of the first motor can be separated more accurately. In addition, the control module obtains key parameters such as the total power loss and current of the motor under different working conditions in real time, and performs loss separation based on these parameters, thereby improving the flexibility and efficiency of the test.

[0078] Based on any of the above embodiments, step S20 includes: Figure 2 Steps S21 to S23 shown:

[0079] Step S21: obtaining the DC resistance of each phase of the second motor and the number of phases of the second motor;

[0080] It should be understood that the DC resistance per phase is the resistance value of the motor winding under DC conditions, which reflects the conductive properties of the winding material and the geometric dimensions of the winding. The DC resistance per phase of the motor can be measured using a microresistance tester. The number of phases refers to the number of independently working electromagnetic phases in the motor, which determines the basic operating characteristics of the motor. For example, the number of motor phases can be 3.

[0081] Step S22: determining the copper loss of the second motor based on the DC resistance of each phase of the second motor, the number of phases of the second motor, and the second current;

[0082] It should be understood that, in this embodiment, the second current is the effective value of the current of the second motor under one operating condition.

[0083] In the specific implementation, the AC copper loss of the second motor is not considered. The copper loss of the second motor is equal to its DC copper loss, which can be calculated by the following formula 1:

[0084] P 2Cu = mI 2 R 2dc Formula 1;

[0085] Where P 2Cu is the motor copper loss, I is the effective value of the current under working conditions, R 2dc is the DC resistance of each phase, m is the number of motor phases, usually 3.

[0086] Step S23: determining the remaining losses of the first motor except the copper loss based on the second total power loss and the copper loss of the second motor.

[0087] It is understandable that the first motor and the second motor have the same losses except copper loss. Subtracting the copper loss of the second motor from the total power loss can obtain the losses of the second motor except copper loss, thereby determining the losses of the first motor except copper loss.

[0088] In this embodiment, directly measuring or calculating various losses of the motor often involves complex physical models and a large amount of experimental data. However, by using the known parameters and measurement data of the second motor, the other losses of the first motor except the copper loss can be indirectly determined, which simplifies the analysis process and improves efficiency.

[0089] Based on any of the above embodiments, step S40 includes: Figure 3 Steps S41 to S43 shown:

[0090] Step S41: obtaining the DC resistance of each phase of the first motor and the number of phases of the first motor;

[0091] For example, the motor manufacturer usually provides a detailed specification or technical manual, which contains various parameters of the motor, including the DC resistance of each phase. The DC resistance of each phase of the first motor can be obtained through the specification or technical manual, or the DC resistance of each phase of the motor can be measured by a measuring instrument (such as a DC resistance meter, a DC bridge, etc.).

[0092] Step S42: determining the DC copper loss based on the DC resistance of each phase of the first motor, the number of phases of the first motor, and the first current;

[0093] In this embodiment, the first current is the effective value of the current of the first motor. In an AC motor, the current is alternating, and the DC copper loss refers to the loss caused by the effective value of the current on the DC resistance of the winding. This loss is constant during the AC cycle and is energy equivalent to the loss caused by the DC current on the resistance. The DC copper loss can be determined based on the product of the square of the effective value of the current, the DC resistance of each phase, and the number of motor phases.

[0094] Step S43: determining the AC additional copper loss based on the total copper loss and the DC copper loss.

[0095] It should be noted that AC additional copper loss refers to the additional copper loss in the winding due to the characteristics of AC (such as skin effect, proximity effect, harmonics, etc.). This part of the loss does not exist under DC conditions, but it cannot be ignored in AC motors.

[0096] The total copper loss of a motor is the sum of its DC copper loss and AC additional copper loss. Therefore, the AC additional copper loss can be calculated by subtracting the DC copper loss from the total copper loss.

[0097] In this embodiment, by calculating the DC copper loss and the AC additional copper loss respectively, the energy loss of the motor during operation can be evaluated more accurately.

[0098] Based on any of the above embodiments, the system further includes a third motor; the control module is in communication connection with the third motor; the third motor and the first motor have different core connection modes, and the losses other than iron loss in the total power loss are the same; the method further includes:

[0099] determining mechanical losses of the first motor, and determining permanent magnet losses of the first motor;

[0100] It should be noted that the third motor can be a variety of types of motors, depending on the needs and design of the system. Since the third motor has a different core connection method from the first motor in the system, but other losses (such as copper loss, permanent magnet loss, and mechanical loss) are the same under the same operating conditions, this means that the third motor is similar to the first motor in function, but differs in certain characteristics (such as iron loss). The following are some possible types of third motors: asynchronous motors, synchronous motors, DC motors, permanent magnet synchronous motors, and specially designed motors (depending on the needs of specific application scenarios, motors with special core connection methods can also be designed. These motors may be optimized for specific iron loss requirements, heat dissipation conditions, or space limitations). In this embodiment and the following embodiments, the first motor is a flat wire winding welded core permanent magnet synchronous motor, and the third motor will be described as a flat wire winding bonded core permanent magnet synchronous motor.

[0101] It is understandable that mechanical loss is the loss caused by friction, vibration and air resistance of mechanical parts (such as bearings, fan blades, etc.) during the operation of the motor. There are mainly the following methods to determine mechanical loss:

[0102] Theoretical calculation method: Based on the design parameters of the motor (such as bearing type, lubrication conditions, rotor blade shape, etc.) and theories of fluid mechanics, tribology, etc., a mathematical model of mechanical loss is established for calculation.

[0103] Experimental measurement method: Run the motor at no-load or low-load on the test bench, and indirectly calculate the mechanical loss by measuring the difference between the motor input power and output power, combined with other known losses (such as copper loss, iron loss, etc.).

[0104] Empirical formula method: Based on the empirical formula summarized from a large amount of experimental data, the mechanical loss of the motor can be quickly estimated. This method is simple and easy to use, but the accuracy may be affected by the applicable scope of the empirical formula and the individual differences of the motor.

[0105] Permanent magnet loss mainly includes eddy current loss and hysteresis loss of permanent magnet materials. The main methods for determining permanent magnet loss are:

[0106] Finite element analysis method: Use electromagnetic field finite element analysis software to perform detailed magnetic field analysis and loss calculation on the permanent magnet area of ​​the motor.

[0107] Equivalent circuit method: The permanent magnet is equivalent to a magnetic flux source. By constructing an equivalent circuit model of the motor and combining the motor's operating parameters and electromagnetic relationships, the loss of the permanent magnet is calculated.

[0108] Experimental measurement and calibration method: By embedding temperature sensors and other measuring elements in the motor, the temperature change of the permanent magnet is monitored in real time, and the loss of the permanent magnet is calculated by combining the thermal and loss characteristics of the permanent magnet material. At the same time, the permanent magnet loss can also be calibrated by conducting comparative experiments with motors with known losses.

[0109] Determining a total iron loss of the first motor based on the first total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss;

[0110] It can be understood that the total iron loss of the motor is the remaining part after deducting the total copper loss, permanent magnet loss and mechanical loss from the total power loss.

[0111] Obtaining a third total power loss of the third motor under the same operating condition;

[0112] Specifically, the third motor is experimentally measured under the same working conditions. The speed, current amplitude, and current angle corresponding to the working conditions are set on the test bench, and the input electrical power is measured using a power analyzer. The output mechanical power is equal to the product of torque and speed. The torque and speed can be measured by a torque sensor. The total power loss can be obtained by subtracting the output mechanical power from the input electrical power.

[0113] Determining the iron loss of the third motor based on the third total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss;

[0114] It should be understood that the total copper loss, permanent magnet loss and mechanical loss of the third motor are the same as those of the first motor.

[0115] The total loss consists of copper loss, permanent magnet loss, mechanical loss and iron loss. Therefore, the iron loss can be obtained by subtracting the total copper loss, permanent magnet loss and mechanical loss from the total power loss.

[0116] Based on the total iron loss of the first motor and the iron loss of the third motor, the iron loss of the first motor caused by the core connection mode is determined.

[0117] It should be noted that in this embodiment and the following embodiments, the iron loss of the motor to be measured includes the total iron loss and the iron loss caused by the core connection method.

[0118] The core connection methods include but are not limited to the following: welding connection, bolt connection, self-adhesive connection, clip connection, groove connection, and bonding.

[0119] The iron loss of the third motor is the total iron loss of the third motor.

[0120] The first motor and the third motor are identical or similar in all aspects except the core connection method. The effect of the core connection method on the iron loss can be indirectly evaluated by comparing the total iron loss of the two motors. After the total iron loss of the first motor and the total iron loss of the third motor are known, the difference in the total iron loss of the two motors is calculated, and the result is the iron loss of the first motor caused by the core connection method.

[0121] In this embodiment, the total iron loss of the first motor is calculated using the known first power total loss, total copper loss, permanent magnet loss and mechanical loss. In addition, the third motor is introduced to determine the iron loss of the first motor caused by the core connection method. Since the third motor is the same as the first motor in the remaining losses except the iron loss, the same total copper loss, permanent magnet loss and mechanical loss can be used, combined with the third power total loss, to calculate the iron loss of the third motor. By comparing the total iron loss of the first motor and the third motor, the difference in iron loss caused by the core connection method is determined. The total iron loss of the motor and the iron loss caused by the core connection method are efficiently separated from the total loss.

[0122] Based on any of the above embodiments, the system further includes a fourth motor; the control module is in communication with the fourth motor; the fourth motor and the first motor have different rotor structures and the same mechanical loss; and determining the mechanical loss of the first motor includes:

[0123] The mechanical loss of the fourth motor under the same operating condition is obtained, and the mechanical loss of the fourth motor is determined as the mechanical loss of the first motor.

[0124] It should be noted that the fourth motor may be a flat wire winding welded iron loss pseudo rotor (rotor permanent magnet is not magnetized) motor.

[0125] In a specific implementation, the fourth motor is experimentally measured under the same operating conditions. The speed, current amplitude, and current angle corresponding to the operating conditions are set on the experimental bench. When the permanent magnet is not magnetized, the fourth motor is started and run, and its mechanical loss data is obtained through measuring tools (such as power meters, torque sensors, etc.). Due to the design characteristics of the fourth motor, its mechanical loss measurement results can be approximately regarded as the mechanical loss of the first motor under the same operating conditions.

[0126] In this embodiment, by introducing a fourth motor having a different rotor structure from the first motor but the same mechanical loss, the mechanical loss under the same working conditions can be accurately measured, eliminating the error that may be introduced due to electromagnetic design differences, making the measurement of mechanical loss more accurate and reliable.

[0127] Based on any of the foregoing embodiments, determining the permanent magnet loss of the first motor includes:

[0128] Acquiring temperature change information of the first motor under the same operating conditions;

[0129] It is understandable that temperature sensors (such as thermocouples, thermistors or infrared thermometers, etc.) can be used to monitor the temperature changes of the first motor during operation under the set working conditions. These sensors should be installed at a position that can accurately reflect the temperature changes of the permanent magnet, such as on or near the surface of the permanent magnet.

[0130] In a specific implementation, the first motor is equipped with a sensor for measuring the temperature of the permanent magnet. The motor is first cooled to room temperature, and then the temperature rise curve of the permanent magnet is recorded while the motor is running under working conditions.

[0131] Based on the temperature change information, a permanent magnet loss of the first motor is determined.

[0132] In the specific implementation, according to the heating curve of the permanent magnet, the slope of the heating curve at the initial moment is observed and recorded as The permanent magnet loss is calculated by the following formula 2:

[0133]

[0134] Where P 1PM is the permanent magnet loss, C is the specific heat capacity of the permanent magnet material, and m is the mass of the permanent magnet.

[0135] In this embodiment, the permanent magnet loss is determined by monitoring the temperature change of the first motor, without disassembling the motor, and the measurement process is simpler and faster.

[0136] Based on any of the above embodiments, the system includes a connected motor under test and a load motor, the motor under test is any one of the first motor, the second motor, the third motor and the fourth motor, and the load motor is any one of the first motor, the second motor and the third motor; and in the same loss determination test, the motor under test and the load motor are selected from different motors; the load motor operates in a speed control mode, and the motor under test operates in a current control mode.

[0137] It should be noted that the speed control mode refers to a control mode in which the speed of the motor is maintained at a preset value or changes according to a preset speed curve by adjusting the input voltage, current or other control parameters of the motor. The current control mode refers to a control mode in which the current of the motor is maintained at a preset value or changes according to a preset current curve by adjusting the input voltage or other control parameters of the motor.

[0138] The load motor runs in speed control mode, which means that the speed of the load motor is constant or adjusted according to a preset speed curve. This control mode enables the load motor to stably provide the required load to the motor under test, thereby simulating the load conditions in actual working scenarios.

[0139] The motor under test is operated in current control mode, in which the current of the motor under test is controlled within a preset range or adjusted according to a preset current curve. The current control mode helps to precisely control the operating state of the motor under test, thereby more accurately measuring its losses.

[0140] Specifically, in a single test, according to the test requirements, one motor is selected from the four motors as the motor under test, and one motor is selected from the remaining three as the load motor. Make sure that the motor under test and the load motor are from different motors to avoid mutual interference. If the rotor permanent magnet of one of the four motors is not magnetized, this motor cannot be used as a load motor. Exemplarily, it is assumed that the first motor is a flat wire winding welded core permanent magnet synchronous motor, the second motor is a Litz wire winding welded core permanent magnet synchronous motor, the third motor is a flat wire winding bonded core permanent magnet synchronous motor, and the fourth motor is a flat wire winding welded iron loss false rotor (rotor permanent magnet is not magnetized) motor. If the first motor is selected as the motor under test, one of the second and third motors can be selected as the load motor; if the second motor is selected as the motor under test, one of the first and third motors can be selected as the load motor; if the third motor is selected as the motor under test, one of the first and second motors can be selected as the load motor; if the fourth motor is selected as the motor under test, one of the first, second, and third motors can be selected as the load motor.

[0141] like Figure 4 As shown, Figure 4 A structural schematic diagram of a flat wire motor loss separation system provided in an embodiment of the present application. In the figure, the motor under test and the load motor are connected by a transmission shaft, and a torque sensor is connected in the middle to measure the torque and speed. The DC power supply supplies power to the motor under test through an inverter, and is connected to a power analyzer to test its current, voltage and electric power. When a prototype is tested, it is installed in the "motor under test" position. At this time, any one of the first motor, the second motor, and the third motor that is not tested can be installed in the "load motor" position to act as a load. During the test, the load motor adopts a speed control mode, and the motor under test adopts a current control mode.

[0142] In this embodiment, the system allows flexible selection of the motor under test and the load motor from multiple motors. This flexibility allows the test to be performed on different types of motors, thereby improving the applicability of the test. By controlling the operating modes of the motor under test and the load motor separately, the actual working conditions can be simulated more accurately to ensure the accuracy of the loss test results. In addition, the system can automatically adjust the control parameters, record the test data, and analyze the test results in real time, greatly reducing the time for manual intervention and data processing.

[0143] In addition, an embodiment of the present application also provides a method for separating the global losses of a flat wire winding permanent magnet synchronous motor, wherein the losses include its copper loss, iron loss, permanent magnet loss and mechanical loss, wherein the copper loss includes its DC part and AC additional part, and the iron loss includes a comparison of its different processing techniques.

[0144] There are 4 prototypes required for the test, and their structural dimensions, assembly processes, etc. are exactly the same, as follows:

[0145] Prototype 1: Flat wire winding welded core permanent magnet synchronous motor;

[0146] Prototype 2: Litz wire-wound welded core permanent magnet synchronous motor;

[0147] Prototype 3: Flat wire winding bonded core permanent magnet synchronous motor;

[0148] Prototype 4: Flat wire winding welded iron loss dummy rotor (rotor permanent magnets are not magnetized) motor.

[0149] Need to ensure:

[0150] 1. Prototype 1 is equipped with a sensor for measuring the temperature of the permanent magnet;

[0151] 2. The number of conductors per slot and the number of parallel branches of Litz wire winding and flat wire winding are equal;

[0152] 3. The stator and rotor cores of the above motors use the same type of silicon steel sheets;

[0153] 4.The permanent magnet model of the dummy rotor motor is consistent with that of other prototypes.

[0154] Test platform such as Figure 4 As shown, the motor under test and the load motor are connected through a transmission shaft, and a torque sensor is connected in the middle to measure the torque and speed. The DC power supply supplies power to the motor under test through the inverter and is connected to the power analyzer to test its current, voltage and electric power. When testing a certain prototype, it is installed in the "motor under test" position. At this time, any one of the prototypes 1, 2, and 3 that is not being tested can be installed in the "load motor" position to act as a load. During the test, the load motor adopts the speed control mode, and the motor under test adopts the current control mode.

[0155] The loss separation is based on the setting:

[0156] 1. The mechanical loss and permanent magnet loss of the four prototypes under the same working condition are equal. The so-called same working condition means that the speed, current amplitude and current angle are equal;

[0157] 2. The output torque of prototypes 1, 2, and 3 under the same working conditions is equal;

[0158] 3. The iron loss of prototype 1 and prototype 2 is equal under the same working conditions;

[0159] 4. The AC copper loss of prototype 2 is not considered;

[0160] 5. The copper consumption of prototype 1 and prototype 3 is equal under the same working conditions.

[0161] The process of separating the losses at each operating point is as follows: Figure 5 As shown, Figure 5 A schematic diagram of a total loss separation process provided in an embodiment of the present application. In the figure, prototype 1 is the focus of attention, that is, prototype 1 is the motor to be tested for total loss separation. After each step in the figure, the permanent magnet loss, mechanical loss, copper loss (including total copper loss, DC copper loss and AC additional copper loss), and iron loss (including total iron loss and additional iron loss caused by welding) of prototype 1 will be obtained.

[0162] In the figure, the total loss of each prototype is obtained by subtracting the output mechanical power from the input electrical power, where the input electrical power is measured by a power analyzer and the output mechanical power is equal to the product of torque and speed, where the torque and speed are measured by a torque sensor.

[0163] The copper loss of prototype 2 is equal to its DC copper loss, which is calculated using the above formula 1.

[0164] Similarly, the DC copper loss of prototype 1 can be calculated by the following formula 3:

[0165] P 1Cudc = mI 2 R1Cudc Formula 3;

[0166] Where P 1Cudc is the DC copper loss, I is the effective value of the current under working conditions, R 1Cudc is the DC resistance of each phase of prototype 1, and m is the number of motor phases, which is usually 3.

[0167] The mechanical loss test method of prototype 1 is as follows: Install prototype 4 on Figure 4 The position of the motor under test is set in the middle, and the load motor is controlled to the specified speed. The torque sensor reading is read at this time. The absolute value of the product of the torque sensor reading and the speed is the mechanical loss at this speed. The mechanical loss is only related to the speed and has nothing to do with the current. The mechanical loss of prototype 4 is the same as that of prototype 1.

[0168] The permanent magnet loss test method of prototype 1 is: cool the motor to room temperature, and then record the temperature rise curve of the permanent magnet under specified working conditions, such as Figure 6 As shown, Figure 6 A schematic diagram of a permanent magnet heating curve provided in an embodiment of the present application. Observe the slope of the heating curve at the initial moment, which is recorded as The permanent magnet loss is calculated using the above formula 2.

[0169] The testing principle is that at the initial moment, heat has not yet been transferred between the stator and rotor, and the temperature rise of the permanent magnet is only caused by the loss of the permanent magnet itself.

[0170] This global loss separation method for flat-wire winding permanent magnet synchronous motor has the advantages of high precision, good reliability, simple process and good versatility.

[0171] Based on the method described in any of the above embodiments, the present application also provides Figure 7 A structural diagram of a control module is shown in FIG. Figure 7 At the hardware level, the control module includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include hardware required for other services. As an example, the control module may include a motor controller and a test bench, wherein the motor controller and the test bench both include a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include hardware required for other services. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the method described in any of the above embodiments.

[0172] Based on the method described in any of the above embodiments, the present application also provides a flat wire motor loss separation system, the system comprising the first motor, the second motor, and a control module as described in any of the above embodiments.

[0173] Based on the method described in any of the above embodiments, the present application also provides a computer program product, which includes one or more computer programs or instructions. The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. When the computer program is executed by a processor, the method described in any of the above embodiments is implemented.

[0174] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0175] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0176] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0177] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0178] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0179] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A method for determining the loss of a flat wire motor, characterized in that: The method is applied to a control module of a flat wire motor loss separation system, the system comprising a first motor and a second motor; the control module is respectively connected to the first motor and the second motor in communication; the first motor is a flat wire winding motor, the second motor has a different winding structure from the first motor, and the other losses in the total power loss except copper loss are the same; the method comprises: Obtaining a first total power loss and a first current of the first motor under the same operating condition, and obtaining a second total power loss and a second current of the second motor; the operating condition includes a rotation speed, a current amplitude, and a current angle; Determine the remaining losses of the first motor except the copper loss based on the second total power loss and the second current; determining a total copper loss of the first motor based on the first total power loss and the remaining losses except the copper loss; Based on the total copper loss and the first current, a DC copper loss and an AC additional copper loss of the first motor are determined.

2. The method according to claim 1, characterized in that The determining the remaining losses of the first motor except the copper loss based on the second total power loss and the second current includes: Obtaining the DC resistance of each phase of the second motor and the number of phases of the second motor; Determining the copper loss of the second motor based on the DC resistance per phase of the second motor, the number of phases of the second motor, and the second current; The remaining losses of the first motor excluding the copper loss are determined based on the second total power loss and the copper loss of the second motor.

3. The method according to claim 1, characterized in that The determining, based on the total copper loss and the first current, the DC copper loss and the AC additional copper loss of the first motor includes: Obtaining the DC resistance of each phase of the first motor and the number of phases of the first motor; Determining the DC copper loss based on the DC resistance per phase of the first motor, the number of phases of the first motor, and the first current; The AC additional copper loss is determined based on the total copper loss and the DC copper loss.

4. The method according to claim 1, characterized in that The system further includes a third motor; the control module is in communication connection with the third motor; the third motor and the first motor have different core connection modes, and the losses other than iron loss in the total power loss are the same; the method further includes: determining mechanical losses of the first motor, and determining permanent magnet losses of the first motor; Determining a total iron loss of the first motor based on the first total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss; Obtaining a third total power loss of the third motor under the same operating condition; Determining the iron loss of the third motor based on the third total power loss, the total copper loss, the permanent magnet loss, and the mechanical loss; Based on the total iron loss of the first motor and the iron loss of the third motor, the iron loss of the first motor caused by the core connection mode is determined.

5. The method according to claim 4, characterized in that The system further includes a fourth motor; the control module is in communication with the fourth motor; the fourth motor and the first motor have different rotor structures and the same mechanical loss; and determining the mechanical loss of the first motor includes: The mechanical loss of the fourth motor under the same operating condition is obtained, and the mechanical loss of the fourth motor is determined as the mechanical loss of the first motor.

6. The method according to claim 4, characterized in that The determining of the permanent magnet loss of the first motor includes: Acquiring temperature change information of the first motor under the same operating conditions; Based on the temperature change information, a permanent magnet loss of the first motor is determined.

7. The method according to any one of claims 1 to 6, characterized in that: The system includes a connected motor under test and a load motor, the motor under test is any one of the first motor, the second motor, the third motor and the fourth motor, and the load motor is any one of the first motor, the second motor and the third motor; and in the same loss determination test, the motor under test and the load motor are selected from different motors; the load motor operates in a speed control mode, and the motor under test operates in a current control mode.

8. A control module, characterized in that: The control module comprises: processor; a memory for storing processor-executable instructions; Wherein, when the processor calls the executable instructions, the operation of any method described in claims 1-7 is implemented.

9. A flat wire motor loss separation system, characterized in that: The system includes a first electric machine, a second electric machine, and the control module of claim 8 .

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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