CN111274669A - Claw pole generator transient temperature monitoring method with thermal parameter calibration function - Google Patents
Claw pole generator transient temperature monitoring method with thermal parameter calibration function Download PDFInfo
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Abstract
A claw pole generator transient temperature monitoring method with a thermal parameter calibration function is based on a claw pole generator transient temperature lumped parameter thermal network calculation model, and key thermal parameters in the thermal network model are checked through experimental data, so that the claw pole generator transient temperature monitoring method has the function of accurately calibrating two key independent variables along with the rotating speed of a generator and the ambient temperature of the generator, and high-precision and high-reliability claw pole generator transient temperature monitoring is achieved. The method comprises the following steps: establishing an initial claw-pole generator lumped thermal network model; calibrating key thermal parameters of the claw-pole generator lumped thermal network model; and (5) monitoring and post-processing the transient temperature of the claw pole generator integrated heat network model.
Description
Technical Field
The invention belongs to an alternating current motor monitoring method, and particularly relates to a claw-pole generator transient temperature monitoring method with a thermal parameter calibration function.
Background
With the development of electromagnetic field theory and motor technology, various alternating current motors and design methods, analysis methods and control strategies of the alternating current motors are continuously generated and developed and are continuously widely applied in various industries. In recent years, new requirements and demands are made on the safety performance, the degree of intelligence and the types of vehicle-mounted electrical equipment of automobiles, and an automobile generator is taken as the most critical 'electric energy hub' of an automobile, and the reliable and stable electric energy output capability and the safe operation period as long as possible become one of hot spots of current automobile generator researches.
At present, a vehicle using an internal combustion engine as a main power machine widely adopts a claw pole generator (hereinafter referred to as a claw pole generator) with a claw-shaped rotor, wherein the claw pole generator generates an excitation magnetic field by a direct current concentrated winding and a permanent magnet together, the rotor is dragged to rotate by the power machine through a transmission device, and the excitation magnetic field cuts an armature winding to output continuous electric energy. The claw-pole generator is limited by the narrow space of an engine cabin of an automobile, and the heat dissipation condition of the claw-pole generator is obviously limited. Data show that the temperature of the motor winding exceeds the maximum temperature of 10 ℃ allowed by the insulation grade, and the insulation life of the motor winding is reduced by half; in addition, the increase in temperature of the claw pole generator may also adversely affect the magnetic performance of the permanent magnet, which may lead to a decrease in the performance of the claw pole generator, which may be manifested by a decrease in the output voltage and a decrease in the output power of the generator, which may adversely affect the normal operation and operation of the automobile and the electrical equipment therein. For this reason, a reasonable electromagnetic solution, a reliable mechanical structure, good heat dissipation conditions and an accurate temperature monitoring method are important means for avoiding the above-mentioned adverse effects, wherein accurate monitoring of the generator temperature is an important guarantee for safe operation of the vehicle. Since the accuracy of the temperature sensor is easily interfered and influenced by the temperature, humidity and electromagnetic factors of the working environment, the method of analyzing and calculating the transient temperature and analyzing and calculating the steady state temperature without depending on the temperature sensor gradually becomes one of the key points of the current research. CN103353926A discloses "a method for monitoring temperature distribution of a motor in real time", which comprises the following steps: 1) constructing a Green function library; 2) obtaining the distribution of heat sources in the motor, and determining the distribution of hot spots in the motor: 3) and obtaining the temperature, the average temperature and the hot spot temperature of the motor at any position according to the heat source distribution in the motor and the Green function library. The method has the characteristics of simple model, rapid calculation and strong real-time performance, but the heat dissipation coefficient of the method strictly depends on the empirical coefficient and formula estimated by the rotating speed of the motor rotor, so the method is suitable for occasions with small environmental temperature change, and the working environmental temperature of the claw-pole generator is influenced by the temperature of the engine room of the automobile engine, so the method is not suitable for monitoring the temperature of the claw-pole generator. CN104408237A discloses a method and a device for obtaining a transient temperature field of a motor, the method comprises: 1) acquiring a first finite element model of the motor; 2) carrying out reduced order processing on the first finite element model so as to obtain a reduced order model of the motor; 3) solving the reduced order model to obtain a calculation result of the reduced order model; 4) and mapping the calculation result to the first finite element model so as to obtain the temperature mapping of each node in the first finite element model at different moments. The method has high calculation efficiency, strong applicability and simple operation, but strictly depends on a finite element model, and the key parameter 'heat dissipation convection coefficient' is obtained by calculating the basic principle of fluidics and an interpolation method, so the accuracy of the method is influenced. International journal IEEE transactions on industry applications, 2014 published an article entitled "thermal-state calculation and free and forced convection heat dissipation coefficients" for claw pole generators, which separately tests the heat dissipation coefficients of the heat dissipation holes of the claw pole motor casing in different environmental temperature intervals by experiments to give a relation between the heat dissipation coefficient and the rotation speed of the generator, but the environmental temperature interval tested by the method is narrow and a specific function relation between the motor temperature and the environmental temperature is not given, so that the wide-range temperature monitoring capability and the online potential of the method are restricted.
Disclosure of Invention
The invention aims to provide a claw pole generator transient temperature monitoring method with a thermal parameter calibration function aiming at the technical problems of the traditional claw pole generator transient temperature monitoring method.
The technical scheme of the invention is as follows:
a claw pole generator transient temperature monitoring method with a thermal parameter calibration function comprises the following steps:
1. establishing initial claw pole generator set total heat network model
Establishing an initial claw pole generator lumped parameter thermal network model by adopting a heat transfer balance equation shown in a formula (1);
in the formula, C is average mass hot melting, the unit is J/(kg.K), m is heating body mass, the unit is kg, theta is temperature rise of the motor, the unit is K, t is time, the unit is s, R is thermal resistance including conduction thermal resistance and convection thermal resistance, and P is heat generated in unit time, and the unit is W.
The input of the claw-pole generator lumped parameter thermal network model comprises the working current of the generator, the iron loss of the stator, the mechanical loss, the rotating speed of the generator, the working voltage and the environmental temperature, and the output is the average temperature of the armature winding and the rotor excitation winding of the stator of the generator.
Variables in the claw-pole generator lumped parameter thermal network model can be divided into three types, namely conduction thermal resistance, convection thermal resistance and loss, and the names and corresponding meanings of the variables are respectively as follows:
the conductive thermal resistance includes RY-W-thermal resistance between stator yoke and winding, RW-TThermal resistance between stator winding and teeth, RT-FThermal resistance between stator teeth and ferrite, RExW-FThermal resistance between excitation winding and ferrite, RCP-RYThermal resistance between claw pole and rotor yoke, RY-MFThermal resistance between stator yoke and casing, RY-EWThermal resistance between winding and end winding, RY-T-determineThermal resistance R between sub-yoke and teethT-CPThermal resistance between stator teeth and claw poles, RF-CPThermal resistance between ferrite and claw pole, RExW-CP-thermal resistance between the excitation winding and the claw pole; convective heat resistance includes R0Thermal resistance, R, between the housing and the airEW-IA-thermal resistance between the end windings and the internal air;
loss includes PTIron loss of stator teeth, PWJoule loss, P, of winding in slotExWJoule loss, P, of field windingYIron loss, P, of stator yokeEWJoule loss, P, of end windingF-eddy current losses in the ferrite;
2. key thermal parameter calibration of claw pole generator total heat network model
2.1, carrying out direct current test, wherein direct current is introduced into a stator winding of the alternating current motor during the test, the whole motor only has stator copper loss and does not have loss in other forms, and the direct current test is used for calibrating the heat conductivity of an equivalent winding; then, carrying out an alternating current test, wherein the purpose of the alternating current test is to calibrate the shell surface heat dissipation coefficient and the winding end heat dissipation coefficient in the claw-pole generator lumped parameter thermal network model;
2.2, firstly, calculating the generator temperature corresponding to the direct current test by using a claw pole generator lumped parameter thermal network model, comparing the calculation result with the direct current test result of the claw pole generator, and repeatedly correcting the equivalent winding thermal conductivity to ensure that the calculation result is consistent with the direct current test result, thereby calibrating the functional relation between the equivalent winding thermal conductivity and the winding temperature;
2.3, calculating the temperature of the generator corresponding to the alternating current test by using the lumped parameter thermal network model of the claw pole generator and the equivalent winding thermal conductivity calibrated by the direct current test; comparing the calculated temperature result with the alternating current test result, correcting and continuously updating the surface heat dissipation coefficient of the shell and the heat dissipation coefficient of the end part of the winding by adopting a least square method until the relative error between the calculated value and the actual measured value is lower than 8 percent; and finally, determining the functional relation between the surface heat dissipation coefficient of the shell and the heat dissipation coefficient of the winding end part and the ambient temperature by a nonlinear fitting method. At the moment, the corresponding shell surface heat dissipation coefficient and winding end heat dissipation coefficient are the low-error key thermal parameters of the claw-pole generator lumped parameter thermal network model;
3. transient temperature monitoring and post-processing of claw-pole generator collective heat network model
Stator copper loss, rotor copper loss and iron loss in the claw pole generator lumped parameter heat network model under different working conditions of the claw pole generator are updated in real time according to the calculated iteration step length, and the accurately calibrated low-error key thermal parameters are applied to the claw pole generator concentrated heat network model, so that the temperature of each component of the generator when the generator operates under different working conditions can be obtained, and the detection of the transient temperature of each component of the claw pole generator is realized.
Preferably, the initial claw-pole generator set total heat network model establishing process in step 1 is as follows: a shell, a stator core, a stator winding, a rotor core, a rotor excitation winding and a permanent magnet in the claw pole generator are defined as units, the stator winding, the rotor excitation winding, the stator core and the permanent magnet of the claw pole generator which generate heat are equivalent to be a heating source unit, the units with the same temperature are lumped to be a key node, and then the conduction thermal resistance and the convection thermal resistance between the nodes are determined according to the physical connection relationship among the components of the claw pole generator.
Preferably, the alternating current test in the step 2.1 means that under the condition that the voltage of the generator terminal is kept unchanged, the thermocouple and the temperature polling instrument which are pre-embedded in the winding are utilized, the environmental temperature is changed through the temperature rise test platform, and the output current and the steady-state temperature of the generator at the rotating speed of 1500-15000rpm are respectively tested at two environmental temperatures of 23 ℃ and 80 ℃.
Preferably, in step 2.2, the determined update value K of the thermal conductivity of the claw-pole generator winding is useds2Comprises the following steps:
Ks20.25123+0.00132T equation 2)
Wherein T is the winding temperature;
preferably, in step 2.3, the magnitudes of the surface heat dissipation coefficient of the enclosure and the end heat dissipation coefficient of the winding are synchronously corrected and updated, the values of the key thermal parameters meeting the set relative errors are defined as accurately calibrated key thermal parameters, the numerical ratio of the key thermal parameters to the initial values of the key thermal parameters at multiple groups of temperatures and multiple groups of rotating speeds is defined as the correction coefficient of the key thermal parameters, and the correction coefficient p of the enclosure and the correction coefficient q of the end heat dissipation coefficient of the winding are respectively shown in formula 3) and formula 4);
p＝-0.84413+2.12741×10-5×n+0.54336×T0.39751+1.04×10-12×n×T0.39751formula 3)
In the formula, n is the rotating speed of the generator, the unit is rpm, T is the ambient temperature, and the value range is 23-80 ℃; the formula for calculating the heat dissipation coefficient of the casing of the claw-pole generator after calibration is as follows
αHou＝p*(15.6+V0.62) Equation 5)
The formula for calculating the heat dissipation coefficient of the end part of the winding after calibration is as follows
αEnd＝q*(VEndλa/dEnd) Equation 6)
Wherein V is the air velocity, VEndIs the winding end gas velocity, dEndIs the end equivalent diameter;
corrected heat dissipation coefficient αHouAnd αEndThe method is applied to a claw-pole generator lumped thermal network model.
Preferably, when the generator temperature corresponding to the alternating current test is calculated by using the claw-pole generator lumped parameter thermal network model in step 2.3, the equivalent winding thermal conductivity used is the equivalent winding thermal conductivity K calibrated by the direct current tests2The accuracy of the thermal calculation is ensured.
Preferably, the ambient temperature is used as an input to the model when the calculated value of the key parameter is corrected in step 2.3.
The invention provides a claw pole generator transient temperature monitoring method with a key thermal parameter accurate calibration function, which can be used for accurately calibrating a key thermal parameter of a claw pole generator lumped parameter thermal network model by fully considering two key factors and independent variables of the rotation speed and the environment temperature of the claw pole generator, so that the quick, accurate and reliable monitoring of the claw pole generator transient temperature is realized, and important references are provided for the follow-up adjustment of an electromagnetic scheme, a mechanical structure and a heat dissipation condition of the claw pole generator.
Drawings
FIG. 1 is a schematic flow chart of a method for monitoring transient temperature of a claw-pole generator with thermal parameter calibration function;
FIG. 2 is a lumped parameter thermal network model node and thermal resistance distribution plot;
FIG. 3 is an illustration of the input and output of the lumped parameter thermal network model of a claw-pole generator of the present invention;
FIG. 4 is a data diagram of the calculation results of the implementation of the method for monitoring the transient temperature of the claw-pole generator with the thermal parameter calibration function in the claw-pole generator for a 2.1kW automobile according to the present invention;
in fig. 1: 1. the method comprises the following steps of (1) establishing an initial claw pole generator integrated heat network model flow, (2) calibrating key thermal parameters of the claw pole generator integrated heat network model, and (3) monitoring transient temperature of the claw pole generator integrated heat network model and performing post-processing.
Detailed Description
The invention is described in more detail below with reference to the drawings and examples of the specification:
example 1
As shown in fig. 1, the method for monitoring the transient temperature of the claw-pole generator with the thermal parameter calibration function includes:
1. establishing initial claw pole generator set total heat network model
Referring to the temperature rise calculation part of the technical manual of the Y2 series three-phase asynchronous motor, and simultaneously defining a shell, a stator core, a stator winding, a rotor core, a rotor excitation winding and a permanent magnet component of the claw pole generator as units according to the structural characteristics of the claw pole generator, and performing unitized equivalent processing and node division, wherein the unitized equivalent processing and the key node division have been reported in detail by more literature data, the invention equivalently changes the stator winding, the rotor excitation winding, the stator core and the permanent magnet of the claw pole generator, which generate heat, into a heating source unit, because the stator winding has the particularity in the thermal analysis of the motor (the temperature is highest under the general condition), except the stator winding, neglects the axial heat transfer among the motor components, and lumped the unit with the same temperature into a key node (each motor component is lumped into a thermal node), the node distribution diagram of the claw-pole generator lumped parameter thermal network is shown in the attached figure 2.
And (3) establishing a claw-pole generator lumped parameter thermal network model by adopting a heat transfer balance equation shown in formula 1).
As shown in fig. 3, the input of the lumped parameter thermal network model of the claw-pole generator includes the working current of the generator, the iron loss of the stator, the mechanical loss, the rotating speed of the generator, the working voltage, and the ambient temperature, and the output is the average temperature of the armature winding and the excitation winding of the stator and the rotor of the generator.
Variables in the claw-pole generator lumped parameter thermal network model can be divided into three types, namely conduction thermal resistance, convection thermal resistance and loss, and the names and corresponding meanings of the variables are respectively as follows:
the conductive thermal resistance includes RY-W-thermal resistance between stator yoke and winding, RW-TThermal resistance between stator winding and teeth, RT-FThermal resistance between stator teeth and ferrite, RExW-FThermal resistance between excitation winding and ferrite, RCP-RYThermal resistance between claw pole and rotor yoke, RY-MFThermal resistance between stator yoke and casing, RY-EWThermal resistance between winding and end winding, RY-TThermal resistance between stator yoke and teeth, RT-CPThermal resistance between stator teeth and claw poles, RF-CPThermal resistance between ferrite and claw pole, RExW-CP-thermal resistance between the excitation winding and the claw pole; convective heat resistance includes R0Thermal resistance, R, between the housing and the airEW-IA-thermal resistance between the end windings and the internal air;
and determining conduction thermal resistance and convection thermal resistance between nodes according to the physical connection relation among the components of the claw-pole generator by adopting a known formula 7) and a known formula 8).
RcL/(λ a) formula 7)
Wherein L is a heat conduction distance, λ is a material thermal conductivity, and A is a heat conduction area.
Wherein α is the convection heat dissipation coefficient, A is the convection heat dissipation area, TsIs the solid surface temperature, TfIs the fluid temperature; wherein the calculation of the conduction area and the convection heat dissipation area requires motor dimensional parameters.
Loss includes PTIron loss of stator teeth, PWJoule loss, P, of winding in slotExWJoule loss, P, of field windingYIron loss, P, of stator yokeEWJoule loss, P, of end windingF-eddy current losses in the ferrite;
2. claw-pole generator lumped parameter thermal network model key thermal parameter calibration
In the initial claw pole generator set total heat network model, values of loss, thermal resistance and thermal capacity in the whole heat network model can be preliminarily determined according to the published literature data, but three key thermal parameters, namely a winding equivalent thermal conductivity parameter, a shell surface heat dissipation coefficient and a winding end heat dissipation coefficient, can change along with different ambient temperatures and rotation speeds of the claw pole generator, and the values of the three key thermal parameters can obviously influence the solving precision and reliability of the whole heat network model, so that further accurate calibration is needed.
2.1 firstly, a direct current test is carried out, and the main purpose of the direct current test is to calibrate the equivalent winding thermal conductivity in the claw-pole generator thermal network model. By introducing an amplitude I into a stator winding of the claw-pole generator1In order to shorten the test time and to avoid damage to the generator, I1The magnitude of the voltage is determined according to 40-60% of rated current of the claw pole generator, the time of introducing direct current is 5 minutes, and the test process is carried out in a closed test platform (hereinafter referred to as an 'adjustable environment temperature test platform') capable of adjusting environment temperatureAnd measuring the temperature of the stator winding of the claw-pole generator by using a temperature sensor and a temperature polling instrument, wherein the temperature measuring range is-40-300 ℃, and the resolution is 0.1 ℃. At the moment, the stator winding of the claw pole generator can be equivalent to a heating source (hereinafter referred to as a stator heat source), because the claw pole generator is in a static state, the heat dissipation process of the heat released by the stator heat source can be called a natural heat dissipation process, and the initial value of the heat conductivity of the claw pole generator winding is calculated according to a formula 9)
Wherein delta1For claw pole generator stator slot insulation thickness, lambda10.36W/(m.k) represents the channel insulation thermal conductivity, λL0.185W/(m.k) is the thermal conductivity of the impregnating varnish, lambdaa0.0305W/(m.k) is the air heat conductivity, lambdad0.205W/(m.k) is the thermal conductivity of the wire paint layer, SfIs the groove filling factor, b is the groove width, KLIs the paint filling factor, d is the outer diameter of the enameled wire, dwIs the bare wire outer diameter.
Secondly, alternating current test is carried out, the alternating current test of the claw pole generator aims at calibrating the heat dissipation coefficient of the shell and the heat dissipation coefficient of the end part of the winding, and the implementation process is as follows: the output end voltage of an armature winding of the claw-pole generator is kept unchanged, the environment temperature is changed by using an adjustable environment temperature test platform through a thermocouple and a temperature polling instrument which are pre-embedded in the winding, and output current and steady-state temperature data (hereinafter referred to as temperature experimental data) at two environment temperatures of 23 ℃ and 80 ℃ and under multiple groups of rotating speeds are respectively measured. The upper limit and the lower limit of the multiple groups of rotating speeds are respectively the highest rotating speed (15000rpm) and the lowest rotating speed (1500rpm) of the claw-pole generator in work, and the multiple groups of rotating speeds are uniformly selected in a rotating speed closed interval formed by the upper limit and the lower limit of rotating speeds.
2.2 first, the DC current I in the DC test is measured1As the stator current input of the claw-pole generator heat network model, four input parameters of stator iron loss, mechanical loss, generator rotating speed and working voltage are set to be zero, and the environment temperature is set to be in direct current testThe actual ambient temperature of the chamber. And respectively comparing the temperature of the stator winding and the temperature of the rotor excitation winding obtained by the calculation of the thermal model with the corresponding test values of the direct current test, and repeatedly adjusting the heat conductivity of the equivalent winding until the calculated values of the temperature of the stator winding and the temperature of the rotor excitation winding are consistent with the actually measured values, thereby calibrating the heat conductivity of the equivalent winding of the claw-pole generator. Determining the heat conductivity update value K of the claw-pole generator winding by using the formula 2)s2。
And 2.3, taking the output current of the generator obtained by the alternating current test as a current input value in a heat network model, wherein the working voltage is the rated output voltage of the generator of 13.5V, the stator iron loss and the mechanical loss are determined by adopting a loss separation method, and the rotating speed and the ambient temperature of the generator are values corresponding to different direct current tests.
Two environmental temperatures, namely the stator winding temperature and the rotor excitation winding temperature under the condition of multiple groups of rotating speeds are calculated through a claw pole generator lumped parameter thermal network model, and the equivalent winding thermal conductivity used in the calculation is the equivalent winding thermal conductivity after direct current test calibration.
And comparing the calculated stator winding temperature with the rotor excitation winding temperature with a result corresponding to an alternating current test, correcting and continuously updating the shell surface heat dissipation coefficient and the winding end heat dissipation coefficient by adopting a least square method until the relative error between the calculated value and an actual measured value is lower than 8%, and finally calibrating the function relation between the shell heat dissipation coefficient and the winding end heat dissipation coefficient of the claw-pole generator and the environment temperature within the temperature range of 23-80 ℃ through nonlinear fitting.
3. The transient temperature monitoring and post-processing of the claw pole generator total heat network model is to monitor the transient temperature of the claw pole generator by using key thermal parameters which pass through a key thermal parameter calibration process of the claw pole generator total heat network model, and meanwhile, the monitored data can be called for lower functions.
Fig. 4 is a data diagram of the implementation calculation result of a 2.1kW automotive claw pole generator based on the claw pole generator transient temperature monitoring method with thermal parameter calibration function of the present invention, and when the claw pole generator transient temperature monitoring method with thermal parameter calibration function of the present invention is adopted, the minimum error between the calculated stator winding temperature and excitation winding temperature and the experimental value is 2 ℃ and the maximum error is 10 ℃, whereas the minimum error between the calculated value and the experimental value obtained by the conventional method (i.e., the calculation method without thermal parameter calibration) is about 5 ℃ and the maximum error is 20 ℃. The method for monitoring the transient temperature of the claw pole generator with the function of accurately calibrating the key thermal parameters considers the influence of the environmental temperature and the motor rotating speed on the key thermal parameters, and simultaneously performs accurate calibration, so that the method can be applied to the claw pole generator to obtain a more accurate result, namely the temperature of the claw pole generator obtained by the application of the method is closer to experimental data.
The claw-pole generator in the embodiment is a 2.1kW six-phase generator, but is also popularized and applied to multi-phase multi-pole situations of other power grades.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The above description is only exemplary of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A claw pole generator transient temperature monitoring method with a thermal parameter calibration function is characterized by comprising the following steps: the method comprises the following steps:
step 1, establishing an initial claw-pole generator set total heat network model
Establishing an initial claw pole generator lumped parameter thermal network model by adopting a heat transfer balance equation shown in a formula (1);
in the formula, C is average mass hot melting, the unit is J/(kg.K), m is heating body mass, the unit is kg, theta is temperature rise of the motor, the unit is K, t is time, the unit is s, R is thermal resistance including conduction thermal resistance and convection thermal resistance, and P is heat generated in unit time, and the unit is W.
The input of the claw-pole generator lumped parameter thermal network model comprises the working current of the generator, the iron loss of the stator, the mechanical loss, the rotating speed of the generator, the working voltage and the environmental temperature, and the output is the average temperature of the armature winding and the rotor excitation winding of the stator of the generator.
Variables in the claw-pole generator lumped parameter thermal network model can be divided into three types, namely conduction thermal resistance, convection thermal resistance and loss, and the names and corresponding meanings of the variables are respectively as follows:
the conductive thermal resistance includes RY-W-thermal resistance between stator yoke and winding, RW-TThermal resistance between stator winding and teeth, RT-FThermal resistance between stator teeth and ferrite, RExW-FThermal resistance between excitation winding and ferrite, RCP-RYThermal resistance between claw pole and rotor yoke, RY-MFThermal resistance between stator yoke and casing, RY-EWThermal resistance between winding and end winding, RY-TThermal resistance between stator yoke and teeth, RT-CPThermal resistance between stator teeth and claw poles, RF-CPThermal resistance between ferrite and claw pole, RExW-CP-thermal resistance between the excitation winding and the claw pole; convective heat resistance includes R0Thermal resistance, R, between the housing and the airEW-IA-thermal resistance between the end windings and the internal air;
loss includes PTIron loss of stator teeth, PWJoule loss, P, of winding in slotExWJoule loss, P, of field windingYIron loss, P, of stator yokeEWJoule loss, P, of end windingF-ferriteMedium eddy current loss;
step 2, calibrating key thermal parameters of lumped thermal network model of claw-pole generator
Step 2.1, performing direct current test, wherein direct current is introduced into a stator winding of the alternating current motor during the test, only stator copper loss exists in the whole motor, no loss in other forms exists, and the direct current test is used for calibrating the heat conductivity of an equivalent winding; then, carrying out an alternating current test, wherein the purpose of the alternating current test is to calibrate the shell surface heat dissipation coefficient and the winding end heat dissipation coefficient in the claw-pole generator lumped parameter thermal network model;
step 2.2, firstly, calculating the generator temperature corresponding to the direct current test by using the claw pole generator lumped parameter thermal network model, comparing the calculation result with the direct current test result of the claw pole generator, and repeatedly correcting the equivalent winding thermal conductivity to ensure that the calculation result is consistent with the direct current test result, thereby calibrating the functional relation between the equivalent winding thermal conductivity and the winding temperature;
step 2.3, calculating the temperature of the generator corresponding to the alternating current test by using the lumped parameter thermal network model of the claw pole generator and the equivalent winding thermal conductivity calibrated by the direct current test; comparing the calculated temperature result with the alternating current test result, correcting and continuously updating the surface heat dissipation coefficient of the shell and the heat dissipation coefficient of the end part of the winding by adopting a least square method until the relative error between the calculated value and the actual measured value is lower than 8 percent; and finally, determining the functional relation between the surface heat dissipation coefficient of the shell and the heat dissipation coefficient of the winding end part and the ambient temperature by a nonlinear fitting method. At the moment, the corresponding shell surface heat dissipation coefficient and winding end heat dissipation coefficient are the low-error key thermal parameters of the claw-pole generator lumped parameter thermal network model;
step 3, monitoring and post-processing transient temperature of the claw pole generator lumped thermal network model
Stator copper loss, rotor copper loss and iron loss in the claw pole generator lumped parameter heat network model under different working conditions of the claw pole generator are updated in real time according to the calculated iteration step length, and the accurately calibrated low-error key thermal parameters are applied to the claw pole generator concentrated heat network model, so that the temperature of each component of the generator when the generator operates under different working conditions can be obtained, and the detection of the transient temperature of each component of the claw pole generator is realized.
2. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: the initial claw pole generator set total heat network model establishing process in the step 1 is as follows: a shell, a stator core, a stator winding, a rotor core, a rotor excitation winding and a permanent magnet in the claw pole generator are defined as units, the stator winding, the rotor excitation winding, the stator core and the permanent magnet of the claw pole generator which generate heat are equivalent to be a heating source unit, the units with the same temperature are lumped to be a key node, and then the conduction thermal resistance and the convection thermal resistance between the nodes are determined according to the physical connection relationship among the components of the claw pole generator.
3. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: the alternating current test in the step 2.1 means that under the condition that the voltage of the generator terminal is kept unchanged, the thermocouple and the temperature polling instrument which are pre-embedded in the winding are utilized, the environmental temperature is changed through the temperature rise test platform, and the output current and the steady-state temperature of the generator at the rotating speed of 1500-plus 15000rpm are respectively tested at two environmental temperatures of 23 ℃ and 80 ℃.
4. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: in step 2.2, the determined thermal conductivity update value K of the claw-pole generator windings2Comprises the following steps:
Ks20.25123+0.00132T equation 2)
Wherein T is the winding temperature.
5. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: synchronously correcting and updating the values of the surface heat dissipation coefficient of the shell and the end heat dissipation coefficient of the winding in the step 2.3, defining the key thermal parameter values meeting the set relative errors as accurately calibrated key thermal parameters, defining the numerical ratio of the key thermal parameters to the initial values of the key thermal parameters under multiple groups of temperatures and multiple groups of rotating speeds as key thermal parameter correction coefficients, and respectively showing the heat dissipation coefficient correction coefficient p of the shell and the heat dissipation coefficient correction coefficient q of the end of the winding in the formula 3) and the formula 4);
p＝-0.84413+2.12741×10-5×n+0.54336×T0.39751+1.04×10-12×n×T0.39751formula 3)
In the formula, n is the rotating speed of the generator, the unit is rpm, T is the ambient temperature, and the value range is 23-80 ℃; the formula for calculating the heat dissipation coefficient of the casing of the claw-pole generator after calibration is as follows
αHou＝p*(15.6+V0.62) Equation 5)
The formula for calculating the heat dissipation coefficient of the end part of the winding after calibration is as follows
αEnd＝q*(VEndλa/dEnd) Equation 6)
Wherein V is the air velocity, VEndIs the winding end gas velocity, dEndThe equivalent diameter of the end part, and the corrected heat dissipation coefficient αHouAnd αEndThe method is applied to a claw-pole generator lumped thermal network model.
6. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: in step 2.3, when the claw-pole generator lumped parameter thermal network model is used for calculating the generator temperature corresponding to the alternating current test, the used equivalent winding thermal conductivity is the equivalent winding thermal conductivity K calibrated through the direct current tests2The accuracy of the thermal calculation is ensured.
7. The method for monitoring the transient temperature of the claw-pole generator with the function of calibrating the thermal parameter as claimed in claim 1, wherein the method comprises the following steps: in step 2.3, the calculated value of the key parameter is corrected by using the ambient temperature as the input of the model.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112213638A (en) * | 2020-10-28 | 2021-01-12 | 瑞声新能源发展(常州)有限公司科教城分公司 | Heating state monitoring method of motor coil, related equipment and medium |
| EP3926426A1 (en) * | 2020-06-15 | 2021-12-22 | ABB Schweiz AG | Method of monitoring an electrical machine |
| CN117172058A (en) * | 2023-09-01 | 2023-12-05 | 哈尔滨理工大学 | Digital twin method for shielding end temperature of motor stator |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3926426A1 (en) * | 2020-06-15 | 2021-12-22 | ABB Schweiz AG | Method of monitoring an electrical machine |
| WO2021254986A1 (en) * | 2020-06-15 | 2021-12-23 | Abb Schweiz Ag | Method of monitoring an electrical machine |
| CN112213638A (en) * | 2020-10-28 | 2021-01-12 | 瑞声新能源发展(常州)有限公司科教城分公司 | Heating state monitoring method of motor coil, related equipment and medium |
| CN117172058A (en) * | 2023-09-01 | 2023-12-05 | 哈尔滨理工大学 | Digital twin method for shielding end temperature of motor stator |
| CN117172058B (en) * | 2023-09-01 | 2024-04-19 | 哈尔滨理工大学 | Digital twin method for shielding end temperature of motor stator |
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