CN110323994B - Method, system, vehicle and storage medium for estimating temperature of motor rotor on line in real time - Google Patents
Method, system, vehicle and storage medium for estimating temperature of motor rotor on line in real time Download PDFInfo
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- CN110323994B CN110323994B CN201910673143.1A CN201910673143A CN110323994B CN 110323994 B CN110323994 B CN 110323994B CN 201910673143 A CN201910673143 A CN 201910673143A CN 110323994 B CN110323994 B CN 110323994B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/60—Controlling or determining the temperature of the motor or of the drive
- H02P29/66—Controlling or determining the temperature of the rotor
- H02P29/662—Controlling or determining the temperature of the rotor the rotor having permanent magnets
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Abstract
The invention discloses a method, a system, a vehicle and a storage medium for estimating the temperature of a motor rotor on line in real time. And secondly, estimating the temperature value of the motor rotor according to the running state of the motor, and then judging the temperature correction condition of the motor rotor to determine to update the temperature value, thereby eliminating the integral accumulation error. And finally, judging the power-off condition of the system to carry out non-loss storage on the corrected rotor temperature, so that the initial temperature of the motor rotor can be estimated after the system is powered on again. The method improves the accuracy of rotor temperature online estimation under the complex operation working condition of the motor.
Description
Technical Field
The invention belongs to the technical field of automobile motors, and particularly relates to a method and a system for estimating the temperature of a motor rotor on line in real time, a vehicle and a storage medium.
Background
The permanent magnet synchronous motor is widely applied to the electric vehicle due to the advantages of high energy density, high efficiency and the like, and the magnetic field intensity of a rotor of the permanent magnet synchronous motor is linearly weakened along with the rise of temperature and is linearly strengthened along with the fall of the temperature. In the control of the permanent magnet synchronous motor, the rotor temperature is obtained to have very important significance, on one hand, as the rotor temperature rises, the torque output capability and precision of the permanent magnet synchronous motor are reduced, and the control deviation of the performance of the whole vehicle is caused; on the other hand, when the temperature of the rotor of the permanent magnet synchronous motor is too high and exceeds a certain critical temperature, the rotor magnetic steel can generate an irreversible demagnetization phenomenon, and the permanent magnet synchronous motor is subjected to use risks.
The temperature of the rotor magnetic steel of the permanent magnet synchronous motor mainly uses a hardware-based temperature sensor acquisition scheme, and the rotor is in a rotating state when the permanent magnet synchronous motor works, so that the motor structure needs to be remanufactured and a sliding ring or a wireless temperature acquisition system is additionally arranged to meet the reliability transmission of a rotor temperature signal, the manufacturing cost of the motor system is increased, and the complex structure brings higher system failure rate. The existing rotor temperature estimation method is to test the corresponding relation between the rotor temperature and the stator temperature by using a test and then obtain the rotor temperature rise by looking up a table through coefficient fitting. However, the existing rotor temperature estimation technology usually ignores dynamic influences of variable load operation of the motor and environmental temperature on temperature change of the stator in actual work, and causes calculation deviation of rotor temperature rise, thereby influencing the working performance of the motor.
Therefore, there is a need to develop a method, system, vehicle and storage medium for estimating the temperature of the rotor of an electric machine on-line in real time.
Disclosure of Invention
The invention aims to provide a method, a system, a vehicle and a storage medium for estimating the rotor temperature of a motor on line in real time, which can improve the accuracy of the rotor temperature on line estimation of the motor under complex operating conditions.
The invention discloses a method for estimating the temperature of a motor rotor in real time on line, which comprises the following steps:
step 1, powering on a system;
step 2, judging the working condition of the motor, if the motor is in a natural cooling state, inquiring a rotor temperature numerical value curve under the natural cooling condition at the current ambient temperature to obtain the initial temperature T of the rotor when the system is powered onr_init；
If the motor is in the running state, estimating the temperature T of the motor rotor at the current moment in the motor running stater2；
Tr2＝Tr1+ΔTr；
Wherein: t isr1The temperature of the motor rotor at the previous moment; delta TrFor the value of the change of the temperature of the rotor in the sampling period；CsThe specific heat capacity of the motor stator is; msThe mass of the motor stator; t iss1The temperature of the stator of the motor at the previous moment; t iss2The temperature of the motor stator at the current moment; pwPower loss for coolant circulation; ps_airPower losses for dissipation into the air through the stator surface; pr_airPower losses for dissipation into the air through the rotor surface; Δ t is a sampling unit time; crThe specific heat capacity of the motor rotor is adopted; mrThe motor rotor mass;
step 3, judging whether the conditions a to c are simultaneously satisfied,
conditions a, ncal_1≤|nmot|≤ncal_2；
Conditions b, | Tmot_trq|≤Tcal；
Condition c, Delta psimot≤Δψcal；
Wherein: n iscal_1Calibrating a low limit value of the motor rotating speed; n ismotThe actual rotating speed of the motor is obtained; n iscal_2Calibrating a value for the high limit of the motor rotating speed; t ismot_trqThe actual torque of the motor; t iscalCalibrating a motor torque limit value; delta psimotThe actual flux linkage change rate of the motor in a sampling period is; delta psicalLimiting a calibration value for the change rate of the motor flux linkage;
if the conditions a to c are not satisfied simultaneously, then for Tr2Judging whether the system is powered off without correction, if not, entering the step 2, and if so, storing Tr2；
If the conditions a to c are simultaneously satisfied, calculating the actual flux linkage psi of the motormotAnd inquiring the corresponding relation between the corrected temperature of the motor rotor and the flux linkage to obtain the corrected temperature T of the motor rotorr_updAnd the temperature T of the motor rotor at the current moment in the motor motion state is controlledr2Is equal to Tr_upd(ii) a Judging whether the system is powered off, if not, returning to the step 2; if yes, the corrected T is storedr2。
Further, in the step 2, Δ T is calculatedrIn which P isw、Ps_airAnd Pr_airThe sum is obtained by checking a system cooling loss power numerical model, wherein the system cooling loss power numerical model is the total cooling loss power P of the systemcool_loss(ΔTsT) and the rate of change of temperature of the stator of the motor Δ TsThe correspondence between them (see fig. 3).
Further, the method for constructing the system cooling loss power numerical model comprises the following steps:
firstly, the total cooling power loss P of the systemcool_loss(ΔTsAt) performs energy equivalent conversion, namely:
Pcool_loss(ΔTs/Δt)＝Pw+Ps_air+Pr_air；
then, the total cooling loss power P of the system is obtained by repeatedly optimizing and calibrating the simulation of the computer according to the errors of the estimated value and the measured value of the rotor temperature under different constant load working conditionscool_loss(ΔTsT) and the rate of change of temperature of the stator of the motor Δ TsUntil the estimation accuracy of the rotor temperature meets the requirements under different environment temperature change load conditions.
Further, the actual flux linkage psi of the motormotThe calculation method of (2) is as follows:
wherein: eΦIs the phase potential amplitude; omegamotIs the electrical angular frequency; emotIs the effective value of the line potential; n ismotThe actual rotating speed of the motor is obtained; p is a radical ofmotThe number of pole pairs of the motor is shown.
Further, in step 2, if the motor is in a natural cooling state, the numerical value curve of the rotor temperature under the natural cooling condition at the current ambient temperature is inquired to obtain the initial temperature T of the rotor when the system is powered onr_initThe method specifically comprises the following steps:
reading the rotor temperature stored in the motor controller when the system is powered off last time and the shutdown time t sent by the battery control systemstopAnd the ambient temperature sent by the vehicle control unitTevir；
Then, a rotor temperature numerical curve under the condition of natural cooling corresponding to the environment temperature in the motor rotor natural cooling numerical model is inquired, and the time point t corresponding to the temperature is found according to the rotor temperature recorded when the system is powered off last time0And adding the shutdown duration tstopTime point of inquiry (t)0+tstop) I.e. obtaining the initial temperature T of the rotor at system power-onr_init。
Further, if the motor rotor natural cooling numerical model does not contain the environmental temperature TevirThe ambient temperature T is taken as the rotor temperature value curve under the natural cooling condition of the ambient temperatureevirThe adjacent temperature is inquired to obtain the initial temperature T of the rotor under the adjacent environment temperature point corresponding to the current environment temperature1、T2And through Tr_init＝λT1+(1-λ)T2Calculating the ambient temperature TevirInitial temperature T of rotorr_init(ii) a Wherein: and lambda is a fitting coefficient.
Further, if the system is stopped for a time period tstopThe heat balance time length of natural cooling to the environment temperature is more than or equal to, the initial temperature T of the rotorr_initIs the ambient temperature Tevir。
The invention discloses a system for estimating the temperature of a motor rotor in real time on line, which comprises a motor controller and a memory, wherein the memory is used for storing data; the motor controller is programmed to perform the steps of the method of real-time online estimation of the temperature of the motor rotor according to the invention.
The invention provides a vehicle comprising the system for estimating the temperature of the rotor of the motor on line in real time.
A storage medium storing one or more programs, which are executable by one or more processors, to implement the steps of the method for real-time online estimation of the temperature of a rotor of an electric machine according to the present invention.
The invention has the following advantages:
(1) the method considers the dynamic influence of the variable load operation of the motor and the environment temperature on the temperature change of the stator in the actual work, thereby improving the accuracy of the online estimation of the rotor temperature of the motor under the complex working condition and further improving the working performance of the motor.
(2) Establishing equivalent conversion of power loss of each key thermal node of the motor system and total cooling loss power of the system, optimizing and calibrating the total cooling loss power of the system corresponding to each temperature change rate of the stator by utilizing computer simulation under different constant load working conditions, and judging whether the numerical model of the total cooling loss power of the system needs to be continuously optimized or not by estimating precision of the temperature of the stator under the variable load working condition.
(3) And constructing a correction model corresponding to the rotor temperature and the flux linkage density through test tests, obtaining a rotor temperature correction value by inquiring the correction model when the motor torque, the rotating speed and the flux linkage change rate meet certain conditions, and updating and correcting the accumulated error generated by the rotor temperature estimation model.
Drawings
FIG. 1 is an energy flow model of each key thermal node in the running state of the motor system of the present invention;
FIG. 2 is a numerical model of the natural cooling of the rotor of the motor according to the present invention;
FIG. 3 is a numerical model of the total cooling power loss of the system according to the present invention;
FIG. 4 is a flow chart of numerical model optimization of total cooling power loss of the system according to the present invention;
FIG. 5 is a model of a motor rotor temperature correction value in accordance with the present invention;
FIG. 6 is a flow chart of a method for controlling the temperature of a rotor of a motor under all operating conditions in accordance with the present invention.
Detailed Description
The invention will be further explained with reference to the drawings.
As shown in fig. 6, a method for estimating the rotor temperature of the motor on line in real time includes the following steps:
step 1, powering on a system.
Step 2, judging the working condition of the motor, and if the motor is in a natural cooling state, judging that the motor is in a natural cooling stateInquiring a rotor temperature numerical value curve under the natural cooling condition at the current environment temperature to obtain the initial temperature T of the rotor when the system is electrifiedr_init；
If the motor is in the running state, estimating the temperature T of the motor rotor at the current moment in the motor running stater2；
Tr2＝Tr1+ΔTr；
Wherein: t isr1The temperature of the motor rotor at the previous moment; delta TrThe temperature change value of the rotor in a sampling period is obtained; csThe specific heat capacity of the motor stator is; msThe mass of the motor stator; t iss1The temperature of the stator of the motor at the previous moment; t iss2The temperature of the motor stator at the current moment; pwPower loss for coolant circulation; ps_airPower losses for dissipation into the air through the stator surface; pr_airPower losses for dissipation into the air through the rotor surface; Δ t is a sampling unit time; crThe specific heat capacity of the motor rotor is adopted; mrIs the motor rotor mass.
Step 3, judging whether the conditions a to c are simultaneously met;
conditions a, ncal_1≤|nmot|≤ncal_2；
Conditions b, | Tmot_trq|≤Tcal；
Condition c, Delta psimot≤Δψcal；
Wherein: n iscal_1Calibrating a low limit value of the motor rotating speed; n ismotThe actual rotating speed of the motor is obtained; n iscal_2Calibrating a value for the high limit of the motor rotating speed; t ismot_trqThe actual torque of the motor; t iscalCalibrating a motor torque limit value; delta psimotThe actual flux linkage change rate of the motor in a sampling period is; delta psicalLimiting a calibration value for the change rate of the motor flux linkage;
if the conditions a to c are not satisfied simultaneouslyThen to Tr2Judging whether the system is powered off without correction, if not, entering the step 2, and if so, storing Tr2；
If the conditions a to c are simultaneously satisfied, calculating the actual flux linkage psi of the motormotAnd inquiring the corresponding relation between the corrected temperature of the motor rotor and the flux linkage to obtain the corrected temperature T of the motor rotorr_updAnd the temperature T of the motor rotor at the current moment in the motor motion state is controlledr2Is equal to Tr_upd(ii) a Judging whether the system is powered off, if not, returning to the step 2; if yes, the corrected T is storedr2。
In this embodiment, the temperature T of the motor rotor at the current moment in the motor motion stater2The calculation formula of (2) is constructed by the following steps:
SA-1, analyzing a heat generation mechanism of each key node in the running process of the permanent magnet synchronous motor, and constructing a heat loss model, wherein the heat loss model specifically comprises the following steps:
firstly, the heat loss generated when three-phase current passes through the section of the stator winding, namely copper loss P, is analyzedCu. The power loss model calculation in its sampling time is as follows:
in the formula: n is the number of motor phases, IPhaseIs phase current, RPhaseIs the phase resistance.
Secondly, the hysteresis loss P generated by the change of the alternating magnetic field caused by the alternating current of the stator winding is analyzedhAnd eddy current loss P generated by induced current caused by magnetic field change in the coreeI.e. iron loss PFe. The power loss model calculation in its sampling time is as follows:
in the formula: k is a radical ofhThe hysteresis loss coefficient (obtained by measuring different frequencies and fitting the magnetic induction intensity); k is a radical ofeIs the eddy current loss coefficient (obtained by measuring different alternating frequencies and fitting through a skin effect equation); k is a radical ofextFitting the additional loss coefficient (obtained by measuring different alternating frequencies through a skin effect and proximity effect calculation formula); f is the alternating frequency of the electric driving magnetic field; b ismIs the stator core flux density amplitude.
The losses caused by the motor bearing rotational friction and by the ventilation, i.e. the mechanical losses P, are then analyzedFr. The power loss model calculation in its sampling time is as follows:
in the formula: k is a radical ofcThe coefficient of surface roughness; cfIs the friction factor; rhoairIs the air density; omegamThe angular velocity of the motor; l is the rotor length; r is the rotor radius.
Finally, the power loss P taken away by the cooling loop is analyzedwAnd power dissipation P of the rotor and stator and their windings to the surroundingsr_airAnd Ps_airI.e. the total cooling power loss of the system.
Stator power loss P taken away by cooling liquidwThe model calculation is as follows:
Pw＝ρwCwAwv(Tin-Tout)/Δt (4)
in the formula: rhowIs the coolant density; cwIs the specific heat capacity of the cooling liquid; a. thewThe sectional area of the cooling pipeline; v is the coolant flow velocity; t isinThe temperature of the inlet water is set; t isoutThe temperature of the effluent is; Δ t is a sampling unit time.
Power dissipation P of rotor and stator and their windings to the surroundingsr_air、Ps_airThe model calculation is as follows:
Pr_air＝δAr(Tr-T0)/Δt (5)
Ps_air＝δAs(Ts-T0)/Δt (6)
in the formula: delta is the convective heat transfer coefficient; a. thesThe convection heat transfer area of the rotor and the winding surface is provided; a. therThe convective heat transfer area of the stator and the winding surface; t issThe rotor and winding surface temperatures; t isrThe surface temperature of the stator and the winding is shown; t is0Is ambient temperature.
The convective heat transfer coefficient δ is calculated as follows:
δ＝9.73+14V0.62 (7)
in the formula: v is the air circulation speed of the heat dissipation surface.
And SA-2, establishing an energy flow model of the motor system (as shown in figure 1) on the basis of analysis of heat generation mechanism and power loss of each key heat node in the motor running state in the step SA-1.
As can be seen from fig. 1, the total power P input to the electric machine systeminThe output power after the power loss involved in the step SA-1 is Pout. The temperature of the motor stator rises mainly due to copper loss PCuIron loss PFeAnd mechanical loss PFrThereby reducing copper to PCuIron loss PFeAnd mechanical loss PFrThe three are equivalent to the motor stator absorbing heat, thereby satisfying the following relations:
PCu+PFe+PFr＝CsMs(Ts2-Ts1)/Δt (8)
in the formula: csThe specific heat capacity of the motor stator is; msThe mass of the motor stator; t iss1For the stator temperature, T, of the motor at the preceding moments2The temperature of the stator of the motor at the current moment.
Meanwhile, the motor stator is used as a heat source, the absorbed power of the motor stator is consumed through four parts, and P is taken away by the first part through cooling liquid circulationwThe second part is dissipated into the air P by the stator surfaces_airThe third part is dissipated into the air P by the rotor surfacer_airThe fourth part is transmitted to the rotor to heat and raise the temperature, namely the heat consumption power P of the motor rotorr. According to the conservation of energy, the energy absorbed by the stator of the motor simultaneously satisfies the following relation:
CsMs(Ts2-Ts1)/Δt＝Pw+Ps_air+Pr_air+Pr (9)
in the formula: prThe heat dissipation power of the motor rotor is obtained.
SA-3, according to the content of the step SA-2, establishing the heat consumption power P of the rotor of the motorrWith stator temperature rate of change (T)s2-Ts1) ,/Δ t, System Cooling loss (P)w、Pr_airAnd Ps_air) The corresponding relation (as shown in equation 9), and the heat dissipation power of the motor rotor satisfies the following relation:
Pr＝CrMr(Tr2-Tr1)/Δt (10)
in the formula: crThe specific heat capacity of the motor rotor is adopted; mrThe motor rotor mass; t isr1For the rotor temperature, T, of the motor at the preceding momentr2The temperature of the rotor of the motor at the current moment.
By combining the formula (9) and the formula (10), the temperature T of the motor rotor at the current moment of the motor running state can be obtainedr2The calculation formula (i.e., the motor rotor temperature estimation formula shown in formula 11 and formula 12) is as follows:
Tr2＝Tr1+ΔTr (11)
it can be seen from the formula (11) that the temperature of the motor rotor at the current moment can be obtained by adding the temperature change value of the rotor in the sampling period to the temperature of the motor rotor at the previous moment. And then, the rotor temperature of the motor at the current moment is used as the initial rotor temperature at the next moment to perform repeated superposition in a sampling period, so that the real-time estimated rotor temperature under the motor running state can be obtained.
In the embodiment, the rotor temperature T stored in the motor control system by obtaining the last power-off of the systemr_pre(i.e., T stored in memory at last power-offr2) The shutdown time t from last power-off to current power-on of the systemstopAnd the ambient temperature TevirCalculating the initial temperature T of the rotor when the system is powered on by adopting the following steps of SB-1 to SB-3r_initThereby improving the accuracy of the rotor temperature estimation.
SB-1, reading the rotor temperature T stored in the motor controller when the motor control system was last powered downr_preAnd the shutdown time t sent by the battery control systemstopAnd the ambient temperature T sent by the vehicle control unitevir。
SB-2, recording the change trend of the motor rotor from the highest temperature to the ambient temperature under each ambient temperature in a test mode, establishing a motor rotor natural cooling numerical model (as shown in figure 2), then inquiring a rotor temperature numerical curve under the natural cooling condition corresponding to the ambient temperature (such as 30 ℃), and recording the rotor temperature T according to the last power-off of the systemr_preFinding the time point t corresponding to the temperature0And adding the shutdown duration tstopTime point of inquiry (t)0+tstop) I.e. obtaining the initial temperature T of the rotor at system power-onr_init。
SB-3: aiming at other environmental temperatures (namely the environmental temperature T is not included in the numerical model of the natural cooling of the motor rotor)evirAs shown in fig. 2, the rotor temperature value curve under the natural cooling condition of the ambient temperature recorded by the motor rotor natural cooling value model has an estimation of the rotor initial temperature at the temperature of 10 ℃, 20 ℃, 30 ℃, 40 ℃, 50 ℃ and 60 ℃, except the above temperatures, the other temperatures are other ambient temperatures), and the method described in steps SB-1 and SB-2 is firstly adopted to obtain the adjacent ambient temperatures (for example: the ambient temperature is 25 ℃, and the adjacent ambient temperatures are the initial temperatures T of the rotor corresponding to the ring temperature of 20 ℃ and the ring temperature of 30 ℃ in FIG. 21、T2And calculating the initial temperature T of the rotor at the ambient temperature by interpolation fitting of a formula (13)r_init. If the system is stopped for a period of time tstopThe thermal equilibrium time length t of natural cooling to the ambient temperature is more than or equal tob-t0(as shown in FIG. 2), the rotor initial temperature T is consideredr_initIs the ambient temperature Tevir。
Tr_init＝λT1+(1-λ)T2 (13)
In the formula: t is1、T2Respectively corresponding to the initial temperatures of the rotors at the adjacent ambient temperature points; lambda is fitting coefficient (value range is [0,1 ]]And calibrating according to the ambient temperature interval).
In this embodiment, in order to improve the operation efficiency and accuracy of the motor rotor temperature algorithm in the controller, on the basis of analyzing the power loss of each key thermal node of the system, the total cooling loss power P of the system is first analyzedcool_loss(ΔTsThe/delta t) is subjected to energy equivalent conversion (as shown in a formula 14), and then the total cooling loss power P of the system is obtained by repeatedly optimizing and calibrating through computer simulation based on the errors of estimated values and measured values of the rotor temperature under different constant load working conditionscool_loss(ΔTsT) and the rate of change of temperature of the stator of the motor Δ TsUntil the estimation accuracy of the rotor temperature meets the requirement under different environment temperature change load conditions, the optimization process is shown in fig. 4.
Pcool_loss(ΔTs/Δt)＝Pw+Ps_air+Pr_air (14)
In the formula: pcool_loss(ΔTsAnd/delta t) is the total cooling power loss of the system corresponding to the temperature change rate of the stator.
In the present embodiment, Δ T is calculatedrIn which P isw、Ps_airAnd Pr_airAnd the sum is obtained by checking a system cooling loss power numerical model.
In this embodiment, the actual flux linkage ψ of the motormotThe calculation method of (2) is as follows:
wherein: eΦIs the phase potential amplitude; omegamotIs the electrical angular frequency; emotIs the effective value of the line potential; n ismotThe actual rotating speed of the motor is obtained; p is a radical ofmotThe number of pole pairs of the motor is shown.
In the embodiment, in order to improve the reliability of the rotor temperature control algorithm, the accumulated error generated in the iterative operation process is eliminated, and the real-time estimation precision of the rotor temperature is ensured. Establishing rotor temperature correction value T by adopting test moder_updWith magnetic linkage psimotIs calculated (i.e. motor rotor temperature correction numerical model, see 5), and then the actual flux linkage psi of the motor is calculated using equation (15)motAnd inquiring the corresponding relation of FIG. 5 to obtain the corrected temperature T of the motor rotorr_upd。
In the formula: eΦIs the phase potential amplitude; omegamotIs the electrical angular frequency; emotIs the effective value of the line potential; n ismotThe actual rotating speed of the motor is obtained; p is a radical ofmotThe number of pole pairs of the motor is shown.
Enabling the motor rotor temperature correction value T under the condition that the conditions in the formula (16) to the formula (18) are simultaneously satisfiedr_updAnd updating the real-time estimated value of the temperature of the motor rotor.
ncal_1≤|nmot|≤ncal_2 (16)
|Tmot_trq|≤Tcal (17)
Δψmot≤Δψcal (18)。
In this embodiment, it is first determined whether the system is powered on, and then the real-time operating state of the motor is determined according to the actual rotational speed and torque of the motor. And secondly, estimating the temperature value of the motor rotor according to the running state of the motor, and then judging the temperature correction condition of the motor rotor to determine to update the temperature value, thereby eliminating the integral accumulation error. And finally, judging the power-off condition of the system to carry out non-loss storage on the corrected rotor temperature, so that the initial temperature of the motor rotor can be estimated after the system is powered on again.
The invention discloses a system for estimating the temperature of a motor rotor in real time on line, which comprises a motor controller and a memory, wherein the memory is used for storing data; the motor controller is programmed to perform the steps of the method of real-time online estimation of the temperature of the motor rotor according to the invention.
The invention provides a vehicle comprising the system for estimating the temperature of the rotor of the motor on line in real time.
A storage medium storing one or more programs, which are executable by one or more processors, to implement the steps of the method for real-time online estimation of the temperature of a rotor of an electric machine according to the present invention.
Claims (10)
1. A method for estimating the temperature of a motor rotor in real time on line is characterized by comprising the following steps:
step 1, powering on a system;
step 2, judging the working condition of the motor, if the motor is in a natural cooling state, inquiring a rotor temperature numerical value curve under the natural cooling condition at the current ambient temperature to obtain the initial temperature T of the rotor when the system is powered onr_init；
If the motor is in the running state, estimating the temperature T of the motor rotor at the current moment in the motor running stater2；
Tr2＝Tr1+ΔTr；
Wherein: t isr1The temperature of the motor rotor at the previous moment; delta TrThe temperature change value of the rotor in a sampling period is obtained; csThe specific heat capacity of the motor stator is; msThe mass of the motor stator; t iss1The temperature of the stator of the motor at the previous moment; t iss2The temperature of the motor stator at the current moment; pwPower loss for coolant circulation; ps_airPower losses for dissipation into the air through the stator surface; pr_airPower losses for dissipation into the air through the rotor surface; deltat is sampling unit time; crThe specific heat capacity of the motor rotor is adopted; mrThe motor rotor mass;
step 3, judging whether the conditions a to c are simultaneously satisfied,
conditions a, ncal_1≤|nmot|≤ncal_2；
Conditions b, | Tmot_trq|≤Tcal；
Condition c, Delta psimot≤Δψcal；
Wherein: n iscal_1Calibrating a low limit value of the motor rotating speed; n ismotThe actual rotating speed of the motor is obtained; n iscal_2Calibrating a value for the high limit of the motor rotating speed; t ismot_trqThe actual torque of the motor; t iscalCalibrating a motor torque limit value; delta psimotThe actual flux linkage change rate of the motor in a sampling period is; delta psicalLimiting a calibration value for the change rate of the motor flux linkage;
if the conditions a to c are not satisfied simultaneously, then for Tr2Judging whether the system is powered off without correction, if not, entering the step 2, and if so, storing Tr2；
If the conditions a to c are simultaneously satisfied, calculating the actual flux linkage psi of the motormotAnd inquiring the corresponding relation between the corrected temperature of the motor rotor and the flux linkage to obtain the corrected temperature T of the motor rotorr_updAnd the temperature T of the motor rotor at the current moment in the motor motion state is controlledr2Is equal to Tr_upd(ii) a Judging whether the system is powered off, if not, returning to the step 2; if yes, the corrected T is storedr2。
2. The method for estimating the rotor temperature of the motor in real time and on line according to claim 1, wherein the method comprises the following steps: in the step 2, atrIn which P isw、Ps_airAnd Pr_airThe sum is obtained by checking a system cooling loss power numerical model, wherein the system cooling loss power numerical model is the total cooling loss power P of the systemcool_loss(ΔTsT) and the rate of change of temperature of the stator of the motor Δ TsThe corresponding relation between them.
3. The method for estimating the rotor temperature of the motor in real time and on line according to claim 2, wherein: the method for constructing the system cooling loss power numerical model comprises the following steps:
firstly, the total cooling power loss P of the systemcool_loss(ΔTsAt) performs energy equivalent conversion, namely:
Pcool_loss(ΔTs/Δt)＝Pw+Ps_air+Pr_air；
then, the total cooling loss power P of the system is obtained by repeatedly optimizing and calibrating the simulation of the computer according to the errors of the estimated value and the measured value of the rotor temperature under different constant load working conditionscool_loss(ΔTsT) and the rate of change of temperature of the stator of the motor Δ TsUntil the estimation accuracy of the rotor temperature meets the requirements under different environment temperature change load conditions.
4. The method for real-time online estimation of the rotor temperature of the motor according to any one of claims 1 to 3, wherein: the actual flux linkage psi of the motormotThe calculation method of (2) is as follows:
wherein: eΦIs the phase potential amplitude; omegamotIs the electrical angular frequency; emotIs the effective value of the line potential; n ismotThe actual rotating speed of the motor is obtained; p is a radical ofmotThe number of pole pairs of the motor is shown.
5. The method for real-time online estimation of the rotor temperature of the motor according to any one of claims 1 to 3, wherein: in the step 2, if the motor is in a natural cooling state, the rotor temperature numerical curve under the natural cooling condition at the current ambient temperature is inquired to obtain the initial temperature T of the rotor when the system is powered onr_initThe method specifically comprises the following steps:
reading the rotor temperature stored in the motor controller when the system is powered off last time and the shutdown time t sent by the battery control systemstopAnd the ambient temperature T sent by the vehicle control unitevir；
Then, a rotor temperature numerical curve under the condition of natural cooling corresponding to the environment temperature in the motor rotor natural cooling numerical model is inquired, and the time point t corresponding to the temperature is found according to the rotor temperature recorded when the system is powered off last time0And adding the shutdown duration tstopTime point t of inquiry0+tstopI.e. obtaining the initial temperature T of the rotor at system power-onr_init。
6. The method for estimating the rotor temperature of the motor in real time on line according to claim 5, wherein: if the motor rotor natural cooling numerical model does not contain the environmental temperature TevirThe ambient temperature T is taken as the rotor temperature value curve under the natural cooling condition of the ambient temperatureevirThe adjacent temperature is inquired to obtain the initial temperature T of the rotor under the adjacent environment temperature point corresponding to the current environment temperature1、T2And through Tr_init＝λT1+(1-λ)T2Calculating the ambient temperature TevirInitial temperature T of rotorr_init(ii) a Wherein: and lambda is a fitting coefficient.
7. The method for estimating the rotor temperature of the motor in real time and on line according to claim 6, wherein the method comprises the following steps: if the system is stopped for a period of time tstopThe heat balance time length of natural cooling to the environment temperature is more than or equal to, the initial temperature T of the rotorr_initIs the ambient temperature Tevir。
8. A system for estimating the rotor temperature of a motor in real time on line comprises a motor controller and a memory, wherein the memory is used for storing data; the method is characterized in that: the motor controller is programmed to perform the steps of the method for real-time online estimation of the temperature of the rotor of the motor as claimed in any one of claims 1 to 7.
9. A vehicle, characterized in that: a system for real-time online estimation of the rotor temperature of an electric machine comprising as claimed in claim 8.
10. A storage medium, characterized by: the storage medium stores one or more programs which are executable by one or more processors to implement the steps of the method for real-time online estimation of the temperature of the rotor of an electric machine according to any one of claims 1 to 7.
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| DE102020111853A1 (en) | 2020-04-30 | 2021-11-04 | Valeo Siemens Eautomotive Germany Gmbh | METHOD OF DETERMINING A TEMPERATURE OF A ROTOR OF AN ELECTRICAL MACHINE |
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| CN116614035B (en) * | 2023-05-29 | 2024-06-28 | 重庆青山工业有限责任公司 | Real-time online estimation method for rotor temperature of permanent magnet synchronous motor |
| CN117200647B (en) * | 2023-11-01 | 2024-03-19 | 浙江万里扬新能源驱动有限公司杭州分公司 | Method for inhibiting working overheat of gear selecting and shifting motor of automobile transmission and vehicle |
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