JP2003315162A - Temperature detecting method using resolver, temperature detecting method for actuator, and electric power steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature detecting method utilizing a resolver which can detect temperature of the resolver and ambient temperature thereof without using a temperature sensor. <P>SOLUTION: Two-phases resolver output signal obtained by applying a first- phase excitation signal to the resolver is expressed as the following equations (1) and (2): Ss=E×Ks×sinθ×sin(ωt+ϕt)+Bs...(1), Sc=E×Kc×cosθ×sin(ωt+ϕt)+Bc...(2). The temperature of the resolver and the ambient temperature thereof are obtained from the two-phases resolver output signal (S111) based on a phase difference between an excitation coil and an output coil in the sin phase ϕs, and a phase difference between an excitation coil and an output coil in the cos phase ϕc (S101 to S109). Therefore, the temperature of the resolver and the ambient temperature thereof can be measured without using the temperature sensor. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting method using a resolver, a temperature detecting method for an actuator, and an electric power steering apparatus.

[0002]

2. Description of the Related Art As a device for detecting the temperature of an actuator without using a temperature sensor such as a thermistor, for example, there is an "electric power steering device control device" disclosed in Japanese Patent Laid-Open No. 10-100913. This is an electric power steering apparatus that detects a steering state, generates an assisting force according to the steering state by a motor, and assists steering by controlling the winding temperature of the motor by a torque sensor that detects a steering torque. It is an estimate.

However, in the case of a torque sensor used in such an electric power steering apparatus, torque is detected by measuring the amount of twist of a torsion bar or the like as the amount of change in the inductance of a sensor coil electromagnetically coupled to the sensor ring. In many cases, the configuration to obtain is adopted (Japanese Patent Laid-Open No. 2000-1
See "Torque Sensor" in Japanese Patent No. 46722). Therefore, even if an attempt is made to detect a steering angle with such a one-coil torque sensor, only a relative steering angle can be detected. Therefore, in an application in which absolute angle detection is required in addition to torque detection, In place of such a torque sensor, a resolver capable of detecting an absolute angle has been used.

[0004]

However, when the resolver is used instead of the torque sensor having the one-coil structure, a temperature sensor for measuring the temperature and a temperature detection circuit for the temperature sensor are separately required. . Therefore, if a structure is adopted in which the torque and the angle are detected by the resolver, there arises new problems that the product cost and the failure rate increase with the increase in the number of parts.

Further, when the torque sensor having the one-coil structure as described above is used in the electric power steering apparatus, since it is necessary to detect the steering torque, the assist force is usually provided in the vicinity of the steering wheel. In many cases, the configuration is such that the motor is physically located away from the motor. Therefore, there is a problem in that a certain degree of detection error may occur if the temperature sensor is used to detect the temperature by using a torque sensor that is distant from the motor.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to use a resolver which can detect the temperature of a resolver and its surroundings without using a temperature sensor. It is to provide a detection method. Another object of the present invention is to provide an actuator temperature detection method and an electric power steering apparatus that can accurately detect the temperature of an actuator or a motor without using a temperature sensor.

[0007]

[Means for Solving the Problems and Actions and Effects of the Invention]
In order to achieve the above object, in the temperature detecting method using the resolver according to claim 1, the two-phase resolver output signal obtained by applying the one-phase excitation signal to the resolver is used as the expression according to claim 1.
When expressed by (1) and (2), φs and the equation of Equation (1)
The technical feature is that the temperature of the resolver or its surrounding temperature is obtained from the two-phase resolver output signal based on φc in (2).

According to the first aspect of the present invention, the temperature of the resolver or its surrounding temperature is obtained from the two-phase resolver output signal based on φs of the equation (1) and φc of the equation (2). Thus, the temperature of the resolver and the temperature around it can be detected without using the temperature sensor.

Further, in the temperature detecting method using the resolver of claim 2, in addition to φs of the formula (1) and φc of the formula (2), the Ks of the formula (1) and The technical feature is that the temperature of the resolver or the ambient temperature thereof is calculated from the output signal of the two-phase resolver based on the equation (2) Kc.

According to the second aspect of the present invention, the temperature of the resolver or the ambient temperature thereof is also obtained from the two-phase resolver output signal based on Ks of the equation (1) and Kc of the equation (2). As a result, φs of the equation (1) and the equation (2)
Not only is the temperature of the resolver or its surrounding temperature determined based on φc of
(2) Since the temperature of the resolver or its surrounding temperature is obtained from the two-phase resolver output signal based on Kc, the temperature can be obtained accurately. Therefore, the temperature of the resolver and the temperature around it can be accurately detected without using a temperature sensor.

Further, according to a third aspect of the present invention, there is provided an actuator temperature detecting method for detecting a temperature of an actuator whose control angle is detected by a resolver. A first step of obtaining a first resolver temperature, which is the temperature of the resolver or its ambient temperature, by the temperature detecting method using the resolver according to claim 1 or 2;
A second resolver temperature, which is a temperature of a second resolver located between the first resolver and the actuator or a temperature around the second resolver, is obtained by a temperature detecting method using the resolver according to claim 1 or 2. 2 steps,
Based on the “first resolver temperature according to the first step”, the “second resolver temperature according to the second step”, and the “heat conduction distance between the first and second resolvers and the actuator”, And a third step of obtaining the temperature of the actuator.

In the invention of claim 3, the first step uses the resolver of claim 1 or 2 as the first resolver temperature which is the temperature of the first resolver located apart from the actuator or the ambient temperature thereof. 3. The resolver according to claim 1 or 2, wherein the temperature of the second resolver located between the first resolver and the actuator or a second resolver temperature which is the ambient temperature thereof is obtained by the second temperature detecting method. The temperature of the actuator is determined based on the first resolver temperature, the second resolver temperature, and the heat conduction distance between the first resolver, the second resolver, and the actuator in the third step. . As a result, the temperature of the actuator is obtained based on the temperature data at two locations such as the first resolver temperature and the second resolver temperature, and the heat conduction distance between the first resolver, the second resolver, and the actuator. By obtaining the temperature gradient per unit heat conduction distance between persons, the temperature of the actuator can be obtained easily and accurately. Therefore, the temperature of the actuator can be accurately detected without using the temperature sensor.

In order to achieve the above object, the electric power steering apparatus according to a fourth aspect of the invention is an electric power steering apparatus that detects a steering state and generates an assisting force according to the steering state by a motor to assist steering. A first resolver, which is a device for obtaining a temperature of a first resolver for detecting the steering state or a first resolver temperature which is an ambient temperature thereof by a temperature detecting method using a resolver according to claim 1 or 2. A temperature detecting means and a second means for detecting the rotation state of the motor
Second resolver temperature detecting means for determining the second resolver temperature, which is the temperature of the resolver or the ambient temperature thereof, by the temperature detecting method using the resolver according to claim 1 or 2, "by the first resolver temperature detecting means". "First resolver temperature", "second by the second resolver temperature detecting means"
It is a technical feature to provide a motor temperature detecting means for obtaining the temperature of the motor based on the "resolver temperature" and the "heat conduction distance between the three members of the first and second resolvers and the motor".

According to the invention of claim 4, the first resolver temperature detecting means detects the steering state, or the temperature of the first resolver or its surrounding temperature, which is the first resolver temperature. The second resolver temperature, which is the temperature of the second resolver for detecting the rotation state of the motor or the ambient temperature thereof, which is obtained by the temperature detecting method used, is detected by the second resolver temperature detecting means.
The temperature is detected by the temperature detecting method using the resolver described above, and the motor temperature detecting means determines the motor based on the first resolver temperature, the second resolver temperature, and the heat conduction distance between the first resolver, the second resolver, and the motor. Find the temperature of. As a result, the temperature of the motor is obtained based on the temperature data at two locations such as the first resolver temperature and the second resolver temperature, and the heat conduction distance between the first and second resolvers and the motor. By obtaining the temperature gradient per unit heat conduction distance between persons, the temperature of the motor can be obtained easily and accurately. Therefore, the temperature of the motor can be accurately detected without using the temperature sensor.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a temperature detecting method, an actuator temperature detecting method and an electric power steering apparatus using a resolver of the present invention will be described below with reference to the drawings. In each of the following embodiments, an example in which the electric power steering apparatus of the present invention is applied to an electric power steering apparatus for a vehicle such as an automobile will be described.

First, the main structure of the electric power steering apparatus 10 according to this embodiment will be described with reference to FIG. As shown in FIG. 1, the electric power steering apparatus 10 mainly includes a steering wheel 11, a steering shaft 12, and a pinion shaft 1.
3, torsion bar 14, resolver 15s for first angle sensor 15, resolver 16s for second angle sensor 16,
The speed reducer 17, the rack and pinion 18, the resolver 19s for the motor rotation angle sensor 19, the motor M, the ECU 20, and the like are configured to detect the steering state by the steering wheel 11 and to provide an assist force corresponding to the steering state to the motor M. And assists the steering by the driver. Wheels (not shown) are connected to both sides of the rack and pinion 18 via tie rods or the like.

That is, one end of a steering shaft 12 is connected to the steering wheel 11, and one end of a torsion bar 14 is connected to the other end of the steering shaft 12. Further, one end of the pinion shaft 13 is connected to the other end of the torsion bar 14, and the pinion shaft 1
A pinion gear of a rack and pinion 18 is connected to the other end side of 3. Further, the steering shaft 12 and the pinion shaft 13 are provided with resolvers 15s and 16s capable of absolutely detecting respective rotation angles (steering angles θ ₁ and θ ₂ ), respectively, and are electrically connected to the ECU 20, respectively. ing.

As a result, the steering shaft 12 and the pinion shaft 13 can be connected relatively rotatably by the torsion bar 14, and the rotation angle of the steering shaft 12 (steering angle θ ₁ ) can be determined by the resolver 15s. 15 and the rotation angle (steering angle θ ₂ ) of the pinion shaft 13 by the second angle sensor 16 by the resolver 16s.
Can be detected respectively. for that reason,
The rotation angle of the steering shaft 12 can be detected as the steering angle θ ₁ by the first angle sensor 15, and
From the angle difference (or deviation) between the steering angle θ ₁ of the steering shaft 12 by the first angle sensor 15 and the steering angle θ ₂ of the pinion shaft 13 by the second angle sensor 16 and the twist amount of the torsion bar 14 from the angle ratio and the like ( The one corresponding to the steering torque) can be detected as the twist angle.

In addition, in the middle of the pinion shaft 13,
The driving force generated by the motor M is transmitted at a predetermined reduction ratio.
The reduction gear 17 is meshed with a gear (not shown),
The driving force of the motor M, that is, the assist force, via the speed reducer 17.
Is transmitted to the pinion shaft 13. It
In addition, this motor M also has its rotation angle (motor rotation angle
θ _MRotation angle by the resolver 19s capable of detecting
A sensor 19 is provided, and this resolver 19s is also E
It is electrically connected to the CU 20.

The resolvers 15s, 16s, 19s (hereinafter referred to as "resolver 1" used in the electric power steering apparatus 10
5s etc. " In all of the above, so-called one-phase excitation, in which a resolver output signal according to the detection angle (electrical angle) can be obtained from the two-phase output coil by applying an excitation signal to the one-phase excitation coil It is of a two-phase output (voltage detection) type.

That is, the resolver 15s and the like are composed of a one-phase exciting coil fixed to the rotor and a two-phase output coil wound so that the electrical angle is shifted by 90 degrees. It is rotatably supported with respect to the phase output coil. Then, one end of the exciting coil is grounded and the other end is electrically connected to the CPU 30 via an AMP 32 described later. The two-phase output coils are electrically connected to the A / D converter of the CPU 30 via AMPs 34 and 36 described later so that one ends thereof are both grounded and the other ends thereof can output output signals independently. Connected to each other.

By configuring the resolver 15s and the like in this way, the excitation signal generated by the CPU 30 and output through the AMP 32 is input to the excitation coil, so that the two-phase output coils are excited and output. Signal S
S and SC are induced. This output signal is given by the following equation (3),
Since it can be expressed as (4), the output signal is A
CPU 30 via MP 34, 36 and A / D converter
Is input to the CPU 30, the rotation angle (electrical angle) θ of the rotor, that is, the rotation angle of the detection target can be calculated by a predetermined calculation process by the CPU 30.

Ss = E.Ks.sin.theta.sin (.omega.t + .phi.s) + Bs ... (3) Sc = E.Kc.cos.theta.sin (.omega.t + .phi.c) + Bc ... (4) The above equations (3), (4) In 4), Ss is the output signal voltage in the sin phase, Sc is the output signal voltage in the cos phase, E
Is the amplitude of the excitation signal, Ks is the transformation ratio between the excitation coil and the output coil in the sin phase, Kc is the transformation ratio between the excitation coil and the output coil in the cos phase, θ is the electrical angle, and ω is the excitation signal. Angular velocity, t is time, φs is the phase shift between the excitation coil and the output coil in the sin phase, φc is the phase shift between the excitation coil and the output coil in the cos phase, and Bs is the sin
The offset voltage of the output signal in the phase, Bc is the offset voltage of the output signal in the cos phase.

Next, the electrical configuration and operation of the ECU 20 and the like which compose the electric power steering apparatus 10 will be described with reference to FIGS.
It will be described based on. As shown in FIG. 2, the ECU 20
Mainly includes the first angle sensor 15, the second angle sensor 16,
The assist torque determination means 21, the current control means 23, the motor rotation angle sensor 19 and the like are included. Specifically, as shown in FIG. 3, the CPU 3 having an A / D converter built therein.
0 (microcomputer), AMP 32, 34, 36
And a memory (not shown) and various interface circuits.

Incidentally, these AMPs 32, 34, 36
Is a buffer amplifier having a function of amplifying voltage or current, and is interposed between the resolver 15s and the like and the CPU 30. As a result, the AMP 32 plays a role of amplifying the one-phase excitation signal output from the output port Po of the CPU 30 to the resolver 15s or the like, and the AMPs 34 and 36 are input from the resolver 15s or the like to the A / D converter of the CPU 30. It serves to amplify the phase resolver output signal.

As a result, the electrical angles (detection angles) detected by the resolver 15s or the like, that is, the steering angles θ ₁ , θ ₂ and the motor rotation angle θ _M are input to the ECU 20 as two-phase resolver output signals. In the ECU 20, the steering angles θ ₁ and θ ₂ and the motor rotation angle θ _M are calculated by the CPU 30 based on these two-phase resolver output signals, as will be described later. Then, based on these calculated steering angles θ ₁ and θ ₂ and the motor rotation angle θ _M , the assist force generated by the motor M is determined as described below.

The first angle sensor 15 detects the steering angle θ ₁ based on the output of the resolver 15s shown in FIG. Similarly, the second angle sensor 16 detects the steering angle θ ₂ based on the output of the resolver 16s. Assist torque determining means 2
1 is the steering angle θ ₁ detected by the first angle sensor 15.
The assist force generated by the motor M is determined based on the steering angle θ ₂ detected by the second angle sensor 16. For example, the steering angle theta _1, the theta ₂ of the angular difference (or deviation) and angle assisted previously set corresponding to such ratio current instruction I _A ^* maps and predetermined arithmetic processing and the like, the assist current command I _A ^* Are seeking.

The current control means 23 includes the actual current I _A flowing through the motor M for the assist current command I _A ^* determined by the assist torque determination means 21, and the motor of the motor M detected by the motor rotation angle sensor 19. Based on the rotation angle θ _M , it is converted into a voltage and the voltage command V ^* is output. That is, the current control means 23 controls to output the target voltage command V ^* by negatively feeding back the actual current I _A flowing in the motor M detected by the current sensor 27.

The motor driving means 25 includes a PWM circuit 24 and
It is composed of switching elements Q1 to Q4.
The PWM circuit 24 is hardware different from the ECU 20.
The pulse width modulation circuit realized by
Voltage command V output from 3 ^*Pulse width according to
It is configured so that a pulse signal can be output for each U phase and V phase.
Has been. This allows the switch to be connected to the output side.
U-phase and V-phase powers corresponding to the gates of the switching elements Q1 to Q4.
Since a loose signal can be given, depending on the pulse width
To turn on / off the switching elements Q1 to Q4
Thus, the drive of the motor M can be arbitrarily controlled.

From the above, the electric power steering apparatus 10 detects the steering state by the first angle sensor 15 and the second angle sensor 16 and causes the motor M to generate an assisting force corresponding to the steering state to drive the driver. The steering can be assisted.

Next, such an electric power steering apparatus 10 will be described.
Angle sensor 1 for detecting the steering torque and steering angle of the vehicle
An example of motor temperature calculation processes 1 to 3 for calculating and detecting the temperature of the motor M using the resolver 16s of 6 and the resolver 19s of the motor rotation angle sensor 19 that detects the motor rotation angle of the motor M is shown in FIG. ~ It demonstrates based on FIG.
The motor temperature calculation processes 1 to 3 described below are all calculated by a program executed by the CPU 30.

First, the motor temperature calculation processing 1 will be described with reference to FIGS. 4 and 7. The motor temperature calculation process 1 shown in FIG. 4 is based on the φs of the equation (3) and the φc of the equation (4) described above, based on the output signals Ss and Sc of the resolver 15s, the temperature of the resolver 15s or the ambient temperature thereof. The temperature T1 of the motor M is detected by obtaining

As shown in FIG. 4, motor temperature calculation processing 1
Then, after a predetermined initialization process, first in step S101, the output signal Ss output from the resolver 15s,
Sc is acquired through the A / D converter and digital values R1 to
The process of obtaining R8 is performed. In this process, the phase 120
Digital values R1 to R8 of 9 points are obtained for each °.

In the following step S103, step S1
Based on the digital values R1 to R8 acquired by 01
A process of calculating the amplitude a0 of the sin approximate expression by the least square method is performed. Specifically, it is calculated by the following equation (5),
For details, refer to Japanese Patent Application No. 2002-1238 by the present applicant.
See the specification for the application of No. 68. a0 = E ・ Ks ・ sin θ ・ cos (φs) ・ ・ ・ (5)

In the next step S105, step S1
Based on the digital values R1 to R8 acquired by 01
A process of calculating the amplitude b0 of the cos approximate expression by the least square method is performed. Specifically, it is calculated by the following equation (6). For the details of the formula (6), refer to the application specification of Japanese Patent Application No. 2002-123868 filed by the applicant of the present invention, as in the case of the formula (5). b0 = E ・ Kc ・ sin θ ・ sin (φc) ・ ・ ・ (6)

Since the amplitude a0 of the sin phase and the amplitude b0 of the cos phase are expressed as shown in equations (5) and (6), the phase shift φ, which is the temperature dependent component, can be expressed by the following equation (7) ) Can be obtained. That is, in step S107, s
Based on the amplitude a0 of the in phase and the amplitude b0 of the cos phase,
The process of calculating the phase shift φ is performed by (7). φ = tan ^-1 (b0 / a0) (7)

When the phase shift φ is calculated in step S107, the process of calculating the temperature T1 based on the phase shift φ is performed in subsequent step S109. Specifically, use an approximate expression of a straight line of the phase shift φ and the temperature T1, or
Alternatively, the phase shift φ is converted into the temperature T1 by using a conversion table or a map created in advance.

As a result, the temperature T1 of the resolver 15s or the like or its surroundings can be obtained based on the output signals Ss and Sc output from the resolver 15s or the like, so that the motor M located near the resolver 15s or the like can be obtained. The initial temperature of can be detected. That is, when there is no difference between the temperature of the resolver 15s and the temperature of the motor M, for example, when the ambient temperature rises such as when the engine is started after a long period of stop or during dead soak, the temperature shown in FIG. If it is based on the output signals Ss and Sc output from the resolver 16s of the two-angle sensor 16, step S1
The temperature T1 (90 ° C. in FIG. 7 (A)) obtained by each processing from 01 to step S109 is directly detected as the temperature of the motor M (□ (white square) shown in FIG. 7 (A)).
mark).

On the other hand, for example, when the engine is restarted shortly after the engine is stopped, the resolver 15s having a small heat capacity is more likely to cool and heat more quickly than the motor M having a relatively large heat capacity. Resolver 15 based on output signals Ss and Sc output from 15s, etc.
The temperature of the motor M cannot be accurately obtained only by calculating the temperature T1 of s or the like or the surrounding temperature T1. Therefore, steps S113 to S117 described below are performed.
Each process is required.

Therefore, in step S111, it is determined whether or not the calculation of the heat radiation amount is necessary, and if it is determined that it is necessary (Yes in S111), the process proceeds to step S113, and it is necessary. If not judged (S11
(No in 1), the temperature T1 obtained in step S109 is set as the temperature of the motor M, and the series of main motor temperature calculation processing 1 is ended.

In step S113, the actual current of the motor M is
Based on the I _A and the voltage command value V ^*, the motor power P
A process of calculating m is performed. Then, step S11
5, the process of calculating the temperature TPm based on the motor power consumption Pm is performed. In the processing in step S115, the motor power consumption Pm is converted into the temperature TPm by using a linear approximation formula of the motor power consumption Pm and the temperature data TPm, or by using a conversion table or map created in advance.

When the temperature TPm is calculated in step S115, the temperature T1 'including the calculation of the heat radiation amount is calculated in the following step S117. That is, step S11
In step 7, the temperature T1 calculated in step S109 (for example, 70 ° C. in FIG. 7B) and the temperature T1 calculated in step S115.
Sum with Pm (for example, 20 ° C. in FIG. 7 (B)) (T1 ′ = T
1 + TPm (for example, 90 ° C. = 70 ° C. + 20 in FIG. 7B)
)), The temperature T1 ′ including the calculation of the heat radiation amount is detected as the temperature of the motor M (□ (white square) mark shown in FIG. 7 (B)).

As described above, in the motor temperature calculation processing 1 shown in FIG. 4, the output signals Ss and Sc of the resolver 15s and the like are converted from the resolver 15s and the like based on the φs of the equation (3) and the φc of the equation (4). The temperature of or around it can be determined. Therefore, the temperature of the resolver 15s and the like, and the temperature of the motor M can be accurately detected without using the temperature sensor.

Next, the motor temperature calculation processing 2 will be described with reference to FIGS. 5 and 7. The motor temperature calculation processing 2 shown in FIG. 5 is based on the Ks of the equation (3) and the Kc of the equation (4) described above, based on the output signals Ss, Sc of the resolver 15s or the like to the temperature of the resolver 15s or the ambient temperature thereof. The temperature T2 of the motor M is detected by obtaining

As shown in FIG. 5, motor temperature calculation processing 2
Then, after a predetermined initialization process, first in step S201, the output signal Ss output from the resolver 15s or the like is acquired via the A / D converter to obtain the digital value G1 and the output signal Sc is converted into the A / D converter. A process of obtaining the digital value G2 through the is performed.

In the following step S203, step S2
On the basis of the digital values G1 and G2 obtained by 01, the processing for calculating the rotation angle θ of the rotor such as the resolver 15s is performed by the following equation (8). θ = tan ^-1 (G1 / G2) (8)

In step S205, step S203
The determination processing of the rotation angle θ calculated by is performed. That is,
Rotation angle θ is 45 ° <θ <135 ° or 225 ° <θ
If <315 ° (Yes in S205), the process proceeds to step S207, and if not (S20).
No in step 5), the process proceeds to step S209.

In step S207, the transformation ratio change K1 / K0 is calculated by the following equation (9). K1 / K0 = G1 / G3 (9) Here, G3 is expressed by the following equation (10) which is a reference equation obtained by measurement in advance, and ωt1 which is the value of ωt at the time of measurement and θ of the time of measurement It is a reference value in which the value θ1 is substituted. Gs = E · Ks · sin (ωt + φs) · sin (θ) (10)

Also in step S209, step S207.
Similarly, the transformation ratio change K1 / K0 is calculated by the following equation (11). K1 / K0 = G1 / G4 (11) Here, G4 is expressed by the following equation (12), which is a reference equation obtained by measurement in advance, and ωt1 which is the value of ωt at the time of measurement and θ of the time of measurement are It is a reference value in which the value θ1 is substituted. Gc = E · Kc · sin (ωt + φc) · cos (θ) (12)

In the next step 211, step S20
7 or transformation ratio change K obtained in step S209
A process of calculating the temperature T2 based on 1 / K0 is performed. Specifically, the transformation ratio change K1 / K0 and the temperature T2 are approximated by a straight line or by using a conversion table or a map created in advance, the transformation ratio change K
Convert 1 / K0 to temperature T2.

As a result, the temperature T2 around the resolver 15s or the like can be obtained based on the output signals Ss and Sc output from the resolver 15s or the like. Therefore, the initial temperature of the motor M located near the resolver 15s or the like can be detected. This means that in step S109 shown in FIG.
In the same way as already explained with reference to (A), the resolver 15
If there is no difference between the temperature of s etc. and the temperature of the motor M, the temperature T2 (90 ° C. in FIG. 7 (A)) obtained by each processing in steps S201 to S211 is the temperature of the motor M as it is. Is detected (marked with □ (white square) in FIG. 7 (A)).

On the other hand, for example, when the engine is restarted shortly after the engine is stopped, the resolver 15s having a small heat capacity is more likely to cool and heat more quickly than the motor M having a relatively large heat capacity. Resolver 15 based on output signals Ss and Sc output from 15s, etc.
The temperature of the motor M cannot be accurately obtained only by calculating the temperature T1 of s or the like or the surrounding temperature T1. Therefore, each process in steps S215 to S219 is necessary, but these processes are the same as each process in steps S113 to S117 shown in FIG. 4, and therefore description thereof will be omitted here.

In step S213, it is determined whether or not the calculation of the heat radiation amount is necessary. If it is determined that it is necessary (Yes in S213), the process proceeds to step S215 and each of steps S215 to S219. Perform processing. If it is not determined to be necessary (No in S213), the temperature T2 obtained in step S211 is set as the temperature of the motor M, and the series of main motor temperature calculation processing 2 is ended.

As described above, in the motor temperature calculation process 2 shown in FIG. 5, the output signals Ss and Sc of the resolver 15s and the like are converted from the resolver 15s and the like based on the Ks of the expression (3) and the Kc of the expression (4). The temperature of or around it can be determined. Therefore, according to the motor temperature calculation processing 1 shown in FIG. 4, φs of the equation (3) and φ of the equation (4) described above are obtained.
Not only detecting the temperature T1 of the motor M on the basis of c, but also detecting the temperature T2 of the motor M on the basis of Ks and Kc, thereby obtaining and detecting the temperature of the motor M in duplicate from different sides. You can Therefore, the temperature of the resolver 15s and the like, and the temperature of the motor M can be detected more accurately without using the temperature sensor.

Subsequently, the motor temperature calculation process 3 will be described with reference to FIGS. 1, 6 and 7. The motor temperature calculation process 3 shown in FIG. 6 is performed by the motor temperature calculation process 1 described with reference to FIG. 4 or the motor temperature calculation process 2 described with reference to FIG. Of the resolver 19 located between the resolver 16s and the motor M by the motor temperature calculation process 2 or the motor temperature calculation process 3 similarly.
By detecting the second resolver temperature Tφm of s, the temperature T3 of the motor M is detected based on the first resolver temperature Tφs, the second resolver temperature Tφm, and the heat conduction distances among the three resolvers 16s and 19s and the motor M. To do.

As shown in FIG. 6, motor temperature calculation processing 3
Then, after the predetermined initialization process, first, in step S301, a process of calculating the first resolver temperature Tφs is performed. That is, as shown in FIG. 1, the first resolver temperature Tφs, which is the temperature of the resolver 16s located away from the motor M or the temperature around it, is calculated as steps S101 to S109 or motor temperature calculation of the motor temperature calculation processing 1 described above. The calculation process of steps S201 to S211 of process 2 is performed. Thereby, for example, the first resolver temperature Tφs indicated by ● (black circle) is obtained as shown in FIGS. 7 (A) and 7 (B).

In the next step S303, a process of calculating the second resolver temperature Tφm is performed. That is, as shown in FIG. 1, the second resolver temperature Tφm, which is the temperature of the resolver 19s located between the resolver 16s and the motor M, or the temperature around it, is calculated from the steps S101 to S109 of the motor temperature calculation process 1 described above. Alternatively, the process of calculating in steps S201 to S211 of the motor temperature calculation process 2 is performed. As a result, for example, the second resolver temperature Tφm indicated by ▲ (black triangle) as shown in FIGS. 7A and 7B is obtained.

In the following step S305, step S3
The first resolver temperature Tφs calculated in 01 and step S3
Based on the second resolver temperature Tφm calculated in 03,
The process of calculating the temperature T3 of the motor M is performed. Specifically, for example, the temperature gradient ΔT per unit heat conduction distance between the resolver 16s and the resolver 19s is calculated by the following equation (1
The temperature of the motor M is calculated by adding the temperature increase / decrease converted to the thermal conduction distance d2 between the resolver 19s and the motor M to the second resolver temperature Tφm as shown in the following equation (14). Calculate T3. ΔT = (Tφs−Tφm) / d1 (13) T3 = ΔT · d2 + Tφm (14) where d1 is the heat conduction distance between the resolver 16s and the resolver 19s, and d2 is the resolver 19s and the motor. It is the heat conduction distance to M.

Further, without depending on the above equations (13) and (14), from the first resolver temperature Tφs, the second resolver temperature Tφm and the heat conduction distances (d1 + d2) among the three resolvers 16s and 19s and the motor M, The temperature T3 of the motor M may be obtained by using an approximate expression or a conversion table or map created in advance.

As a result, as shown in FIGS. 7A and 7B, the first resolver temperature Tφs (marked with ● (black circle) in the figure) and the second resolver temperature Tφm (▲ (black triangle) in the figure). mark)
From this, the temperature T3 of the motor M (marked with a white circle in the figure) can be obtained. Therefore, as shown in Fig. 7 (A),
If there is no difference between the temperatures of the resolvers 16s and 19s and the temperature of the motor M, for example, even when the ambient temperature rises, such as when the engine is started after a long period of stop or at the time of dead soak, FIG. Motor temperature calculation 1 and 2 described with reference
In the case of, 90 (marked with □ (white square) shown in Fig. 7 (A))
It is possible to detect the temperature of the motor M or the temperature around it more accurately than (° C) (○ shown in Fig. 7 (A)).
(Open circle 70 ° C.).

Further, for example, when the engine is restarted shortly after the engine is stopped, the resolvers 16s and 19s having a smaller heat capacity are more likely to cool and heat more quickly than the motor M having a relatively large heat capacity. 16
temperature T1 of the resolvers 16s, 19s or their surroundings based on the output signals Ss, Sc output from s, 19s,
Even when the temperature of the motor M cannot be accurately calculated only by calculating T2, the case of the motor temperature calculation 1 and 2 described with reference to FIGS. 4 and 5 (shown in FIG. 7B). The temperature of the motor M or the temperature around it can be detected more accurately than the temperature of 90 ° C. marked with a □ (white square) (80 marked with a white circle in FIG. 7 (B)).
C).

As described above, in the electric power steering apparatus 10, in step S301, the first resolver temperature Tφs, which is the temperature of the resolver 16s for detecting the steering torque or its surrounding temperature, is set to the motor temperature shown in FIG. The second resolver temperature Tφm, which is the temperature of the resolver 19s for detecting the motor rotation angle θ _M of the motor M or the ambient temperature thereof, is obtained by the calculation process 1 or the motor temperature calculation process 2 shown in FIG. 5 or the motor temperature calculation processing 2 shown in FIG. 5, and in step S305, the first resolver temperature Tφs, the second resolver temperature Tφm, and the resolver 1 are calculated.
The temperature T3 of the motor M is calculated based on the heat conduction distance between the three members of 6s and 19s and the motor M. Thereby, for example, the temperature gradient ΔT per unit heat conduction distance between the resolver 16s and the resolver 19s is calculated by the above equation (13), and further, as shown in the above equation (14), the resolver 19s and the motor M are The temperature increase / decrease converted to the heat conduction distance d2 of
Since the temperature T3 of the motor M is calculated by performing the calculation in addition to the resolver temperature Tφm, the temperature T3 of the motor M can be easily and accurately obtained. Therefore, the temperature of the motor M can be accurately detected without using the temperature sensor.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of an electric power steering apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing main configurations of an ECU and a motor drive circuit shown in FIG.

FIG. 3 is a block diagram showing a connection configuration between an ECU and a resolver.

FIG. 4 is an ECU of the electric power steering apparatus according to the present embodiment.
5 is a flowchart showing a flow of a motor temperature calculation process 1 executed by.

FIG. 5 is an ECU of the electric power steering apparatus according to the present embodiment.
6 is a flowchart showing a flow of a motor temperature calculation process 2 executed by.

FIG. 6 is an ECU of the electric power steering apparatus according to the present embodiment.
5 is a flowchart showing a flow of a motor temperature calculation process 3 executed by.

FIG. 7 is an explanatory diagram showing a temperature relationship between a resolver 16s, a resolver 19s, and a motor M by a heat conduction distance among three parties.

[Explanation of symbols]

10 Electric Power Steering Device 11 Steering Wheel 15 First Angle Sensor 16 Second Angle Sensor 15s Resolver 16s Resolver (First Resolver) 19 Motor Rotation Angle Sensor 19s Resolver (Second Resolver) 20 ECU 30 CPU (First) Resolver temperature detection means, second resolver temperature detection means, motor temperature detection means) M motor (actuator) θ ₁ , θ ₂ steering angle θ _M motor rotation angle (control angle) S301 (first step, first resolver temperature detection means) ) S303 (second step, second resolver temperature detecting means) S305 (third step, motor temperature detecting means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B62D 113: 00 B62D 119: 00 119: 00 137: 00 137: 00 H02K 11/00 DF term ( (Reference) 2F077 AA31 AA43 AA49 FF34 PP26 TT21 TT66 3D032 CC30 DA03 DA15 DA63 DA64 DA67 DC02 DC10 EA01 EB11 EC23 GG01 3D033 CA03 CA11 CA16 CA17 CA20 CA21 5H611 AA01 BB03 PP01 PP05 QQ04 QQ06 UA01 RR01TT0202

Claims (4)

[Claims] 1. When a two-phase resolver output signal obtained by applying a one-phase excitation signal to a resolver is expressed by the following equations (1) and (2), Ss = E.Ks.sin.theta.sin (.omega.t + .phi.s) + Bs ・ ・ ・ (1) Sc = E ・ Kc ・ cos θ ・ sin (ωt + φc) + Bc ・ ・ ・ (2) In the above formulas (1) and (2), Ss is the output signal voltage in the sin phase, and Sc is the cos phase. , E is the amplitude of the excitation signal, Ks is the transformation ratio between the excitation coil and the output coil in the sin phase, Kc is the transformation ratio between the excitation coil and the output coil in the cos phase, and θ is the electrical angle. , Ω is the angular velocity of the excitation signal, t is the time, φs is the phase shift between the excitation coil and the output coil in the sin phase, φc is the phase shift between the excitation coil and the output coil in the cos phase, and Bs is the output signal in the sin phase. Offset voltage, Bc is the offset voltage of the output signal in the cos phase Then, the temperature of the resolver or its ambient temperature is obtained from the two-phase resolver output signal based on φs of the above equation (1) and φc of the above equation (2). Detection method. 2. In addition to φs of the equation (1) and φc of the equation (2), based on Ks of the equation (1) and Kc of the equation (2), the two-phase resolver output signal The temperature detecting method using the resolver according to claim 1, wherein the temperature of the resolver or the temperature around it is determined. 3. A method for detecting the temperature of an actuator, wherein the temperature of an actuator whose control angle is detected by a resolver is detected, which is the temperature of a first resolver located apart from the actuator or a temperature around the first resolver. A first step of obtaining the 1 resolver temperature by the temperature detecting method using the resolver according to claim 1; and a temperature of a second resolver located between the first resolver and the actuator or a temperature around the second resolver. A second step of obtaining a second resolver temperature, which is a temperature, by the temperature detecting method using the resolver according to claim 1 or 2, "a first resolver temperature of the first step", and a "second resolver of the second step". Based on the "resolver temperature" and the "heat conduction distance between the first and second resolvers and the actuator". And a third step of obtaining the temperature of the actuator, the method for detecting the temperature of the actuator. 4. An electric power steering apparatus for detecting a steering state and assisting steering by generating an assisting force according to the steering state by a motor, comprising: a first resolver for detecting the steering state. A first resolver temperature detecting means for obtaining a first resolver temperature, which is a temperature or its surrounding temperature, by a temperature detecting method using the resolver according to claim 1 or 2, and a second resolver for detecting a rotation state of the motor. Second resolver temperature detecting means for obtaining the second resolver temperature, which is the temperature of or around it, by the temperature detecting method using the resolver according to claim 1 or 2, "the first resolver temperature detecting means “Resolver temperature”, “second resolver temperature by the second resolver temperature detecting means” and “heat transfer between the first resolver temperature, the second resolver temperature and the motor”. An electric power steering apparatus comprising: a motor temperature detecting unit that obtains the temperature of the motor based on a "guide distance".