JP2002320397A - Motor rotor position estimating apparatus, position estimating method and program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor rotor position estimating apparatus for operating a low voltage IPM motor up to a high speed rotation. SOLUTION: This motor rotor position estimating apparatus comprises a position estimating part (30) for estimating the position (θM) of a rotor of motor. The position estimating part (30) estimates the position (θM) of rotor based on a speed electromotive force constant (KE) of the motor and the speed electromotive force constant (KE) is KEM (n) obtained by the formula [1/ KE]M(n)=[1/KE]M(n-1)+KKΔiγ +αsgn(Δiγ(n)). Here, KEM(n-1) is the speed electromotive force constant before the position (θM) of rotor is estimated, Kk is the electromotive force constant estimating gain, Δiγ is a difference between the estimated current (iγ) estimated to be detected from the motor and a real current (id) flowing actually into the motor, and α is a sufficiently small value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor rotor position estimating apparatus, position estimating method and program, and more particularly to motor rotation used for sensorless control capable of operating a low-voltage IPM motor up to high rotation. The present invention relates to a child position estimation device, a position estimation method, and a program.

[0002]

2. Description of the Related Art As demands for energy saving and low pollution increase worldwide, due to problems such as exhaust gas and noise, the market for battery-powered vehicles tends to expand in place of engine driving.
Current battery cars are mainly driven by DC motors,
The DC motor requires replacement of the brush and has a low regenerative ability, so that the travelable distance per charge is small. On the other hand, there is a strong need for an AC motor drive having advantages such as high maintainability, high efficiency, and downsizing.

[0003] AC motors with a small number of brushes are roughly classified into a cage induction motor and a permanent magnet synchronous motor (PM motor). Among them, the PM motor has recently been able to be downsized due to the rapid improvement in magnet performance. An IPM motor in which a permanent magnet is embedded in a rotor has high efficiency because reluctance torque generated by magnetic saliency can be effectively used in addition to the magnet torque by the permanent magnet. Further, by using the field weakening control together, the operating range can be significantly expanded even under the limitation of the motor supply voltage and the current. IPM motors having such characteristics are widely used in applications requiring a wide range of variable speeds, such as electric vehicles and motors for air conditioners. Regarding this, the first document (Morimoto, Matsui, Takeda:
"Current Status and Report of Reluctance Torque Applied Motors", IEEJ, Vol. 119, No. 10, 1145 (1999), Second Document (IEEJ Technical Report No. 719, "Reluctance Torque Applied Motors and Control Systems" (1999)) And the third document (Isobe / Hoshino / Morimoto: "Design method of embedded magnet type motor for low voltage", Rotary Machinery Research Fund RM-00-26 of the Institute of Electrical Engineers of Japan).

The performance of an IPM motor largely depends on a control method for optimally extracting a magnet torque and a reluctance torque, and it is necessary to perform an appropriate current control in consideration of a device constant. For that purpose, it is necessary to control the current phase according to the rotor position. On the other hand, in order to improve environmental resistance and reduce costs, without attaching a rotor position sensor,
Sensorless control for controlling the IPM motor is also required at the same time. Various proposals have been made for the sensorless control method of the IPM motor. Regarding this, in the fourth document (Takeshita, Ichikawa, Lee, Matsui: "Sensorless salient-pole brushless DC motor control based on speed electromotive force estimation""
117 volume 1, p. 99-104 (1997)), the fifth
Literature (Ichikawa, Takeshita, Matsui: "Starting method and stability of sensorless salient-pole type brushless DC motor" SPC-95-95, 129 (1992)
5)), 6th document (Watanabe, Takeshita, Matsui: "Zero-speed control of sensorless salient-pole type brushless DC motor", Institute of Electrical Engineers of Japan, SPC-97-7, SPC-97-7, (1997)), No. 7.
References (Takeshita, Ichikawa, Matsui, Yamada, and Mizutani: "Estimation method of initial position and angle of sensorless salient-pole type brushless DC motor", Electricity D, Vol. 116, No. 7, (1996));
Usui / Takeshita / Matsui: "Parameter Estimation Method for Salient-Pole PMSM", 1999 IEEJ National Convention 4-472, (199
9)) is known.

As described above, in order to sufficiently extract the torque of the IPM motor, position information (= angle information) of the magnetic poles of the rotor is required. Conventionally, a rotor position detection sensor has been used to obtain this position information. Various control methods without a position sensor have been devised due to needs such as high reliability, low cost, and miniaturization.

[0006] The large torque IPM motor has a large speed electromotive force constant, and thus generates a large electromotive force during high rotation. Therefore, extremely weak field control is performed. That is, the field-weakening current (= d-axis current) is extremely large with respect to the torque current (= q-axis current). For this reason, a slight dq-axis position estimation error affects the generated torque.

Since it is impossible to estimate the position at low speed, no large torque is generated at low speed.

With respect to position estimation in a stationary state and at a low speed, the following technique disclosed in Japanese Patent Application Laid-Open No. 9-238495 is known. Even when the rotor is stationary or rotating at a low speed, the rotational position (electrical angle) of the rotor is detected without a sensor. The electrical angle is obtained by utilizing the difference in inductance between the phases depending on the angle of the rotor. A voltage I is applied between predetermined phases, and a current I flowing in each phase of UVW according to an inductance which varies depending on the angle of the rotor at that time.
u, Iv, and Iw are detected at the same time, and the electrical angle is determined from the previously stored relationship between the three. Also, in the first step, the electrical angle φ is determined by an approximate calculation in any range of 0 to π or π to 2π, and the second angle is obtained by utilizing the asymmetry of the maximum current with respect to the voltage applied between the phases. In the step, the range to which the electric angle belongs is specified. As a result, the electrical angle θ is uniquely determined.

With respect to position estimation during normal rotation, the following technique disclosed in Japanese Patent Application Laid-Open No. 8-308286 is known. In a synchronous motor having salient poles, a rotation angle of a rotor is detected without using a sensor, and the detected rotation angle is used to control the synchronous motor. The currents Iu and Iv flowing through the stator coil are detected, and the rotation angle is detected by the rotation angle estimating unit therefrom. This estimation has a synchronous motor model inside the synchronous motor control device, and the deviation Δθ between the rotation angle of the model and the actual rotation angle is proportional to the deviation between the actual Id current of the motor and the current Iγ of the model, The deviation of the motor angular velocity is
This is performed using the fact that it is proportional to the difference between the actual current Iq of the motor and the current Iδ of the model. Further, the rotational angular velocity can be obtained as a moving average, assuming that it does not actually fluctuate greatly. In this case, the sampling time can be reduced to improve the calculation speed.

In addition, regarding the position estimation during normal rotation,
The following technique described in Japanese Patent Application Laid-Open No. 10-174499 is also known. This is a control method in which the magnetic axis can be specified in the entire speed range and the speed can be controlled continuously regardless of the speed command.
In a sensorless control method for continuously controlling a permanent magnet type synchronous motor from a zero speed to a high speed range, a real motor rotation speed is defined by d as a magnetic axis of the motor, q as an axis advanced by 90 ° from the d axis. γ-δ, where γ is the coordinate dq axis rotating at ω _R and the designated magnetic axis of the motor, and δ is the axis advanced by 90 ° from the γ axis.
When the axis is set and the rotation speed ω _R γ of the γ-δ axis is determined, the distribution gain K1 and the rotation speed command ω _RREF are set so as to decrease as the absolute value of the rotation speed command ω _RREF increases. A distribution gain K2 that is set to increase as the absolute value increases is prepared, K1 is set to the rotational speed command ω _RREF, and K is set to the speed estimation value ω _RP obtained from the induced voltage of the synchronous motor or the estimated value of the induced voltage.
The rotational speed ω _R γ of the γ-δ axis of the designated magnetic axis is determined by adding the products each multiplied by 2.

[0011]

Conventionally, no method has been established for operating an IPM motor up to a high rotation. In particular, a method of operating a low-voltage IPM motor up to a high rotation has not been established.

There is a need for a method of operating a motor while controlling it with high precision. There is a demand for a method of operating up to high rotation while controlling the position information of the rotor of the motor with high accuracy. In particular, a method for operating a low-voltage IPM motor up to a high rotation is desired. It is desired that the IPM motor achieve both high torque in a stationary state and high-speed operation. It is applied to a battery forklift and the like, and it is desired that the required torque can be realized with a limited low voltage such as a battery voltage.

An object of the present invention is to provide a motor rotor position estimating device, a position estimating method, and a program for operating a motor while controlling the motor with high accuracy. It is another object of the present invention to provide a motor rotor position estimating device, a position estimating method, and a program for driving a motor to high rotation. Still another object of the present invention is to provide
An object of the present invention is to provide a motor rotor position estimating device, a position estimating method, and a program for driving a low-voltage motor to high rotation. Still another object of the present invention is to provide a motor rotor position estimating device, a position estimating method, and a program for operating a low-voltage IPM motor up to high rotation. It is still another object of the present invention to provide a motor rotor position estimating device, a position estimating method, and a program for achieving both high torque and high-speed operation of an IPM motor in a stationary state. Still another object of the present invention is applied to a motor of an electric vehicle such as a battery forklift, and a position estimating device of a motor rotor for realizing a required torque at a limited low voltage such as a battery voltage.
A position estimation method and a program are provided.

[0014]

Means for solving the problem are expressed as follows. The technical matters corresponding to the claims in the expression are appended with parentheses (), numbers, symbols, and the like. The numbers, symbols, etc. clearly indicate the correspondence / correspondence between the technical matter corresponding to the claim and the technical matter of at least one of the plural forms of implementation. It is not intended to indicate that the technical matter is limited to the technical matter of the embodiment.

The motor rotor position estimating apparatus of the present invention
A motor rotor position estimating device including a position estimating unit (30) for estimating a position (θ _M ) of a motor rotor, wherein the position estimating unit (30) includes a speed electromotive force constant ( Based on K _E ), the position of the rotor (θ _M )
And the speed electromotive force constant (K _E ) is K _EM (n) obtained by the following equation.

(Equation 8) Here, the K _EM (n−1) is the speed electromotive force constant before the position (θ _M ) of the rotor is estimated,
The K _k is an electromotive force constant estimation gain, and the Δiγ
Is the difference between the estimated current (i _γ ) estimated to be detected from the motor and the actual current (id) actually flowing through the motor, and the α is a sufficiently small value.

A motor rotor position estimating apparatus according to the present invention comprises:
A motor rotor position estimating device including a position estimating unit (30) for estimating a position (θ _M ) of a motor rotor, wherein the position estimating unit (30) includes a speed electromotive force (e) of the motor. _M (n)) and the estimated speed electromotive force (e _M (n)) and the speed electromotive force constant (K
_E ), the position of the rotor (θ _M ) is estimated,
The speed electromotive force constant (K _E ) is K _EM (n) obtained by the following equation.

(Equation 9) Here, the K _EM (n−1) is the speed electromotive force constant before the position (θ _M ) of the rotor is estimated,
The K _k is an electromotive force constant estimation gain, and the Δiγ
Is the difference between the estimated current (i _γ ) estimated to be detected from the motor and the actual current (id) actually flowing through the motor, and α is the gain of the sigmoid function. It is a small value.

In the motor rotor position estimating device of the present invention, the term K _k Δiγ in the above equation has a fast response, and the term αsgn (Δiγ) has a slow response.

In the motor rotor position estimating apparatus of the present invention, the term αsgn (Δiγ) has a time constant of 10 seconds or more.

In the motor rotor position estimating device according to the present invention, the motor is an IPM motor.

In the motor rotor position estimating apparatus according to the present invention, the (maximum torque speed: maximum speed) of the motor is (1: 8) or more.

According to the motor rotor position estimating apparatus of the present invention,
A motor rotor position estimating device for estimating a position (θ _M ) of a rotor of a motor, wherein a current detected from the motor is determined based on an applied voltage (v ^* ) applied to the motor. current estimating unit for estimating a estimated current (i _gamma) and (25), the estimated current (i _gamma) before is estimated (n
And the applied voltage (v ^*) current detector for detecting the actual current (id) which actually flows in the motor by -1), on the basis of the actual current (id) and the estimated current (i _gamma),
A position estimating unit (3) for estimating the position (θ _M ) of the rotor
0), and the position estimating unit (30) estimates the position (θ _M ) of the rotor by the following equation,

(Equation 10) Here, the θ _M (n) is the estimated position (θ _M ) of the rotor, and the θ _M (n−1) is the position of the rotor before the estimation. , T is the cycle when the current is controlled, K _E is the speed electromotive force constant of the motor, e _M (n) is the estimated speed electromotive force, Z is a correction amount of the position estimation error, and K _EM (n) obtained by the following equation is substituted for the K _E in the above equation.

(Equation 11) Here, the K _EM (n−1) is the speed electromotive force constant before the estimation, the K _k is an electromotive force constant estimation gain, and the Δiγ is the estimated current (i _γ). )
And the actual current (id), and α is a sufficiently small value.

In the motor rotor position estimating apparatus of the present invention, the Z is obtained by the following equation.

(Equation 12)Where K_θIs a position estimation gain, and the ω_M0
(N-1) is the speed of the rotor before the estimation.
Yes, the Δi_γ(N) is the estimated current (i _γ) And before
This is the difference between the actual currents (id).

In the motor rotor position estimating device of the present invention, Δi _γ (n) is the difference between the d-axis current (id) as the actual current and the γ-axis current (i _γ ) as the estimated current. is there.

In the motor rotor position estimating apparatus of the present invention, Δi _γ is the d-axis current (i
d) and the difference between the estimated current and the γ-axis current (i _γ ).

The motor rotor position estimating apparatus of the present invention
And the estimated speed electromotive force e _M(N) is the following formula
Required by

(Equation 13)Here, the e_M(N-1) is the speed before the estimation.
Ke is a speed electromotive force estimation gain.
Yes, the Δi_δ(N) is the estimated current (i _M) And before
This is the difference between the actual currents (i).

In the motor rotor position estimating apparatus of the present invention, Δi _δ (n) is a difference between the q-axis current (iq) as the actual current and the δ-axis current (iδ) as the estimated current. .

In the motor rotor position estimating apparatus according to the present invention, the position estimating section (30) is configured to determine the position (θ) of the rotor during operation of the motor regardless of the number of rotations of the motor.
_M ).

In the motor rotor position estimating device according to the present invention, the position estimating unit (30) applies a pulse voltage of the same magnitude to the U, V, and W phase windings of the motor when the motor is stationary. Then, the magnitudes of the currents flowing through the U, V, and W phase windings are compared, and the position of the rotor is estimated based on the result of the comparison.

In the motor rotor position estimating apparatus according to the present invention, the position estimating section (30) superimposes a pulse voltage (Vγ) on the d-axis command voltage when the motor is running at a low speed, and changes the current change amount at that time. , The difference between the estimated rotor position (θ _M ) and the actual rotor position is estimated.

In the motor rotor position estimating device according to the present invention, the maximum torque of the motor is 125 [Nm], and the maximum rotation speed of the motor is 4350 [rpm].

The motor of the present invention is a motor to which the motor rotor position estimating device of the present invention is applied.

An electric vehicle according to the present invention is an electric vehicle to which the motor according to the present invention is applied, and a low voltage of a battery mounted on the electric vehicle is used as a power source for the motor.

The air conditioner of the present invention is an air conditioner to which the motor of the present invention is applied.

The method for estimating the position of the motor rotor according to the present invention is as follows.
A position estimation method of the motor rotor for estimating the position of the motor rotor (θ _{M), (a)} on the basis of the motor speed electromotive force constant (K _E), the position of the rotor (theta _M ), And (b) the speed electromotive force constant ( _KE ) is calculated by the following equation.
Performing (a) as _EM (n);

[Equation 14] Here, the K _EM (n−1) is the speed electromotive force constant before the position (θ _M ) of the rotor is estimated,
The K _k is an electromotive force constant estimation gain, and the Δiγ
Is the difference between the estimated current (i _γ ) estimated to be detected from the motor and the actual current (id) actually flowing through the motor, and the α is a sufficiently small value.

The program of the present invention is a program for causing a computer to execute each step of the motor rotor position estimating method of the present invention.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, an embodiment of a motor rotor position estimating apparatus according to the present invention is an IPM.
A method of sensorless control over the entire speed range of the motor will be described.

Since the large torque IPM motor has a large speed electromotive force constant, it generates a large electromotive force during high rotation. Therefore, extremely weak field control is performed. That is, the field-weakening current (= d-axis current) is extremely large with respect to the torque current (= q-axis current). For this reason, a slight dq-axis position estimation error affects the generated torque. Motor parameter error is
This causes a slight position estimation error. At the time of high rotation, since this slight error cannot be ignored, it is necessary to use motor parameter correction together to operate the low-voltage IPM motor to high rotation. Among the motor parameters, the speed electromotive force constant is used for position estimation during normal rotation. Hereinafter, the present embodiment will be described in detail.

1. In the present embodiment, a method of operating an IPM motor that realizes low-speed, large-torque and high-speed operation (speed at maximum torque: maximum speed = 1: 8) under low-voltage power supply conditions by sensorless control, and a sensorless control method The result of applying is described.

In the present embodiment, a method based on pulse voltage application is used for position estimation at rest, a method based on pulse voltage superposition is used for position estimation at extremely low speed, and a rotation based on speed electromotive force estimation is performed during normal rotation. The child position estimation method is used.

In the present embodiment, in order to realize high-speed operation under a low-voltage power supply condition, it is required to perform more accurate position estimation. Therefore, in the present embodiment, the position estimation in the stationary state and the low-speed state described above (<2.1>, <
2.2>), position estimation during normal rotation (<2.3>)
In addition to this, a speed electromotive force constant correction is incorporated to enable more accurate position estimation (FIG. 13).

As shown in FIG. 13, "stationary position estimation" is performed at rest (), and "normal rotation position estimation" is performed after rotation starts regardless of the number of rotations (). When the “position estimation during normal rotation” is performed, the value after the correction of the speed electromotive force constant is used (). Also, when the motor speed is as low as 100 rpm,
In addition to the "position estimation at normal rotation", the "position estimation at low speed (error estimation)" is performed ().

In the position estimation during the normal rotation, an angle (position) estimation error is calculated from an error between the d-axis current and the γ-axis current (Equations (5) and (6) described later). In the present embodiment,
The speed electromotive force constant is corrected using a feedback loop (FBL in FIG. 12) having a larger time constant (Equation (8)), and the position and speed during normal rotation are calculated using the corrected speed electromotive force constant. The estimation is performed (FIGS. 6 and 12).

2. Rotor Position Estimation Theory <2.1> Estimation of Rotor Position at Standstill To estimate the rotor position at standstill, the saliency of the IPM motor is used. That is, as shown in FIG. 1, the same magnitude of the pulse voltage is applied to the U, V, and W phase windings, the magnitude of the current flowing in each phase is compared, and the rotor position is estimated. N
To determine the polarity of the pole and the S pole, a pulse voltage large enough to cause magnetic saturation is applied.

In the estimation of the rotor position at rest in <2.1>, the above-mentioned fifth document, seventh document and Japanese Patent Application Laid-Open No.
The method described in Japanese Patent No. 38495 can be employed.

<2.2> Estimation of Rotor Position at Very Low Speed The salient polarity of the IPM motor is also used for estimating the rotor position at very low speed where the induced voltage due to rotation is small.

Definition of dq axis and γδ axis The dq axis and γδ axis of the IPM motor are defined as shown in FIG. The dq axis recognized by the controller is called the γδ axis.

In the IPM motor, the axis through which the magnetic flux formed by the permanent magnet passes through the rotor in the radial direction is called the d axis,
The axis through which the magnetic flux formed by the stator coil of the stator passes through the rotor in the radial direction is called the q-axis. For example, if the number of poles is 4,
Both dq axes are electrically at an angle of 90 degrees. In other words, the axis in phase with the no-load induced electromotive force E0 of the IPM motor is the q-axis, and the axis orthogonal to the vector is the d-axis, and vector decomposition of each phase current I is performed on these dq axes. Thus, the operation of the IPM motor can be easily grasped and controlled.

Voltage Equation The dq-axis equivalent circuit and voltage equation of the IPM motor are shown in FIG.
And (1).

(Equation 15)

The torque generation formula of the IPM motor is given by (2)
It is an expression.

(Equation 16) If the dq axis and the γδ axis match, even if Vγ is applied, the torque should have little effect. Therefore, the pulse component Vγ is superimposed on the d-axis command voltage, and the difference between the estimated position and the actual rotor position is estimated from the current change amount at this time (FIG. 4). Since the motor has saliency, if there is a position estimation error, the influence on the dq axes changes according to the position estimation error.

Equation representing position estimation error The estimation error Δθ is shown in FIG. Here, I represents a direct current amount, and is represented by equation (3).

[Equation 17] T is a pulse voltage application time.

The rotor position estimation at <2.2> at extremely low speed is described in the above-mentioned sixth document and Japanese Patent Application Laid-Open No. 9-238495.
The method can be performed by the method described in Japanese Patent Application Laid-Open Publication No. H10-26095.

<2.3> Estimation of Rotor Position During Normal Rotation For the number of rotations at which an induced voltage is generated, a rotor position estimation method based on speed electromotive force estimation is used as shown in FIG. That is, in the controller, a virtual motor model as shown in Expression (4) having a motor constant that has been measured in advance is constructed.

(Equation 18)

The position estimation during normal rotation is performed as follows. In the virtual motor model (4) in the controller, from the applied voltage of the previous time (= (n-1) times),
(N) times of the detected current is estimated (FIG. 5). The estimated currents are i _γ (n) and i _δ (n). Note that id _M
= I _Mγ = i _γ and iq _M = i _Mδ = i _δ .
Further, in the present specification and the drawings, a difference only in whether or not a character is subscripted does not indicate a difference in the content. The current that actually flows is detected based on the previously applied voltage (FIG. 5). From the difference between the estimated current and the actual current, the speed electromotive force is estimated by equation (5), and the position is calculated from equation (6) (FIG. 5). In addition, because the processing is performed discretely,
The current processing is set to the current time (= (n) times), and the immediately preceding processing is set to the previous time (= (n-1) times).

When the rotational speed changes, the speed electromotive force changes.
However, the influence is exerted on the δ-axis current. Estimated position is off
And γ-axis current, so as shown in equation (6)
Γ-axis current error Δi_γCan be corrected from equation (5)
Δ-axis current error Δi _δSpeed electromotive force
I can correct it. However, the rotor position depends on the direction of rotation.
Since the sign changes, an sgn function is inserted.

[Equation 19]

(Equation 20) Here, the second term on the right side of the equation (6) is one current control cycle (T).
It represents the amount of movement between positions. _Ke is a speed electromotive force estimation gain, and _Kθ is a position estimation gain. Δi _δ = iq−i _δ . Δi _γ = id-i _γ . _Ke is a speed electromotive force estimation gain for correcting the speed electromotive force by multiplying the current estimation error. K _θ is a position estimation gain for correcting the estimated position by multiplying the current estimation error. _KE is a speed electromotive force constant of the motor.

The estimation of the rotor position during normal rotation in <2.3> is performed by the method described in the above-mentioned fourth document, Japanese Patent Application Laid-Open Nos. 8-308286 and 10-174499. Can be.

[0056] From <2.4> velocity correction electromotive force constant (6), in the position estimation based on the estimated speed electromotive force, that parameter error of IPM motor, in particular the speed electromotive force constant K _E greatly affects I can see. The speed electromotive force constant is estimated by the equation (7).

(Equation 21)

The correction of the speed electromotive force constant in <2.4> is described in connection with the eighth document.

Here, in <2.4> of the present embodiment, the correction of the speed electromotive force constant is performed by equation (8).

(Equation 22) Here, the second term on the right side of the equation (8) has a fast response,
Since α is a sufficiently small value, the third term on the right side of the equation (8) has a slow response as a result. The third term on the right side of equation (8) is a large time constant of 10 seconds or more (the response is slow)
have. Here, the “fast response” is a response with a time constant of several seconds or less, and corrects the speed electromotive force constant immediately after the start of control. The “slow response” is a gradual response having a time constant of 10 seconds or more, and responds to a speed electromotive force constant that changes depending on the winding temperature during energization. The time constant of the third term on the right side of the equation (8) is represented by a sigmoid (sgn) function,
The value of the time constant is preferably 10 seconds or more. The reason why the numerical value is preferable is that it is a term for following a change in which the speed electromotive force constant of the motor changes gradually with the winding temperature. The value of α in the third term on the right side of the equation (8) is the gain of the sigmoid function that determines the time constant, and is 10 ⁻³ (rpm
/ V) is preferred. The reason why the numerical value is preferable is that it is a term for following a change in which the speed electromotive force constant of the motor changes gradually with the winding temperature.

In conventional speed electromotive force constant correction, equation (8)
The slow responsiveness corresponding to the third term on the right side of was not considered. In the present embodiment, highly accurate position estimation can be performed by performing correction in consideration of this. The reason why it is necessary to perform the above-described highly accurate position estimation is that it is necessary to operate the low-voltage IPM motor up to high rotation.

Next, the current control of the IPM motor of this embodiment will be described with reference to FIGS.

The IPM of the present embodiment described below
A technique related to motor current control is disclosed in Japanese Patent Application Laid-Open No. 8-308.
No. 286. According to the present embodiment and the technology described in the publication, `` the rotational angular velocity of a synchronous motor having a rotor having salient poles is detected, the rotational angular velocity is used to estimate the angle of the rotor, and The synchronous motor is controlled by controlling the energization of the three-phase coil based on the control of the three-phase coil. "

Japanese Patent Application Laid-Open No. 8-308286 discloses the following matters. Assuming that the deviation between the actual rotational angular velocity of the rotor and the rotational angular velocity estimated based on the model is proportional to the current deviation between the q-axis current and the δ-axis current, the estimated rotational angular velocity of the rotor is calculated from the previous estimated rotational angular velocity. And the current deviation. Assuming that the deviation between the actual rotation angle of the rotor and the rotation angle estimated based on the model is proportional to the current deviation between the d-axis current and the γ-axis current, the estimated angle of the rotor is
It is determined from the previous estimated angle, the estimated rotational angular velocity, and the current deviation. The deviation Δθ between the actual rotation angle of the synchronous motor and the rotation angle estimated using the model is the actual motor current iγ
(Current corresponding to the d-axis current id) and the current iγ of the model, and the deviation Δα between the actual angular velocity of the synchronous motor and the rotational angular velocity estimated using the model is the actual motor current iδ ( (a current corresponding to the q-axis current iq) and the current iδ of the model. If the actual rotation angle and the angle estimated using the model match well, Δθ ≒
Since it is 0, it can be replaced with Δiγ ≒ Δid, Δiδ ≒ Δiq.

FIG. 6 shows the overall configuration for performing the current control of the present embodiment. As shown in FIG. 6, a torque command T ^* is input from the outside by analog voltage input. The torque command T ^* is the current command id in the optimum current table 21.
^* , Iq ^* and the difference between the detected currents id, iq
I control 22 is performed.

Reference numeral 23 denotes a voltage command calculation unit, which is based on the deviation between the current commands Id ^* and Iq ^* given based on the load condition of the IPM motor 14 and the like and the current id and iq, and is based on the dq coordinate axis. Upper target voltages vd ^* , vq ^*
Is calculated. Here, the currents id and iq are actually I
Three-phase currents iu, iv, iw flowing through PM motor 14
Is converted by the three-phase / two-phase converter 24 into a current i on the dq coordinate axis.
These values are converted as d and iq.

The two-phase / three-phase converter 26 converts the target voltages vd ^* and vq ^* commanded by the voltage command calculator 23
The target voltages vu, vv, vw of the phase are converted. A PWM control unit (not shown) is provided at a stage preceding the inverter 13. The PWM control unit includes three-phase target voltages vu, vv, vw
Is converted into a duty in order to realize by turning on and off a DC power supply (not shown). Voltages applied to each of the three-phase coils of the IPM motor 14 are controlled by controlling six switching elements provided in the inverter 13 based on an on / off signal from the PWM control unit.

The three-phase / two-phase converter 24 is provided for the IPM motor 1
Based on the detected U-phase current iu, V-phase current iv, W-phase current iw, and the estimated rotor position θ _M (in the case of no sensor), the currents id and iq on the dq coordinate axes are calculated.

In FIG. 6, the broken line shows the case with a sensor, and in this case, the position and speed are calculated from the resolver signal. Speed / position estimation unit 4 for sensorless operation
In step 1, the rotor position / speed is estimated from the command voltages vd ^* , vq ^* , the feedback currents id, iq, and the like. The estimated position indicated by theta _M, indicating an estimated speed omega _MO.

The inverter 13 in FIG. 6 corresponds to the inverter in FIG. 5, and the IPM motor 14 in FIG. 6 corresponds to the IPM motor 14 in FIG.

FIG. 12 shows a detailed configuration of the speed / position estimating section 41 of FIG.

As shown in FIG. 12, the speed / position estimating section 4
1 is the command voltage vd ^* , vq ^* and the feedback current i
d, based on iq (input of the controller in the motor model 25), and outputs the estimated position theta _M and the estimated velocity omega _MO.

Reference numeral 25 in FIG. 12 corresponds to the virtual model 25 in the controller in FIG. 5, and reference numeral 30 in FIG.
Corresponds to the position / velocity estimation algorithm unit 30 of FIG.
The low-speed position estimating unit 29 in FIG. 12 performs “rotor position estimation at extremely low speed” described in section <2.2>.

As shown in FIG. 12, the motor model 25 in the controller uses the previous (n-1) applied voltages vd ^* , vd
The current detected (n) is estimated from q ^* . Δi _γ , Δ which are differences between the estimated currents i _γ (n), i _δ (n) and the currents id, iq actually flowing by the previous applied voltage
i _δ is input to the position / velocity estimation algorithm unit 30.

The position / speed estimation algorithm unit 30 includes a speed electromotive force estimation unit 31, a speed error estimation unit 32, an LPF
(Low-pass filter) 33, speed estimating unit 34, and position estimating unit 35.

The speed electromotive force estimator 31 receives the δ-axis current error (Δiδ (n)) and corrects the previous speed electromotive force e _M (n−1), as shown in the above equation (5). Then, the current speed electromotive force e _M (n) is estimated.

The electromotive force constant correction unit denoted by reference numeral 51 in FIG.
2.4> “correction of speed electromotive force constant” described in equation (8)
I do. The electromotive force constant correction unit 51 is added to the speed / position estimation unit 41.
Is one of the features of the present embodiment.

The electromotive force constant correction unit 51 receives Δi _γ (= id−i _γ ) and corrects the previous speed electromotive force constant K _E (n−1), as shown in equation (8). Then, the corrected speed electromotive force constant K _EM (n) is output.

The speed estimating unit 34 and the position estimating unit 35 estimate the corrected speed electromotive force constant _KE and the speed electromotive force output from the speed electromotive force estimating unit 31 as shown in equation (6). The value e _M (n) is input and the estimated position value θ _M
(N) is output.

As shown in FIG. 6, the speed / position estimating section 41
Outputs an estimated position value θ _M (n). The three-phase / two-phase conversion unit 24 receives the estimated value θ _M (n) of the position,
From the detected currents iu, iv, iw from the PM motor 14, d
The current is converted into currents id and iq on the axis and the q axis.

3. Test Apparatus <3.1> Outline FIG. 7 shows a schematic view of the test apparatus. Power supply is battery voltage (D
C48V). Main circuit switching element is IGBT
A module (600A) is used. A resolver is provided as a position sensor for debugging, and it is possible to compare a rotor position obtained by estimation with a resolver reading value.

<3.2> IPM Motor The operating characteristics required for the motor and the specifications of the supplied power are shown below. FIG. 8 shows the required operation characteristics. Rotational speed where the field of weakness is wide and maximum torque is required: Maximum rotational speed =
1: 8.

(Operating characteristics required for the motor and power supply specifications) Maximum output: 8.8 kW Maximum torque: 154.2 Nm (at 540 rpm) Maximum rotation speed: 4,350 rpm (at 14.0 Nm) Rated output: 8. 8 kW Rated torque: 47.7 Nm Rated speed: 1,760 rpm Maximum effective motor input voltage between terminals: 31.6 V Maximum effective motor current value 226 A Current phase: 0 ° to 85 °

FIG. 15 shows the constants of the motor. FIG.
9 shows a measured value of a motor constant. The winding resistance R is 0.
00947 [Ω]. The speed electromotive force constant _KE is set to 0.
0264 [Vrms / rpm]. d-axis inductance _{L d} is a 0.346 [mH]. q-axis inductance _{L q} is a 0.462 [mH]. Salient pole ratio ρ
Is 1.34.

<3.3> Controller The controller specifications of the IPM motor are shown below. CPU: HD6477034F20 (SH7034) CPU operating frequency: 20 MHz Current control cycle: 200 μsec

4. Test results <4.1> Position estimation results Figure 9 shows the position estimation results during sensorless operation. It is an estimation result from a standstill to about 1,000 rpm. The thin line is the estimation result, and the thick line is the resolver reading. Position estimation at rest (<2.1>) is completed in 0.3 seconds immediately after servo-on, and when the speed is lower than 100 rpm, position estimation at extremely low speed (voltage of 16.3 V every 12.8 msec is applied for 1.6 ms).
ec) (<2.2>) and position estimation based on speed electromotive force estimation (every 200 μsec) (<2.4>). At 100 rpm or more, only position estimation (<2.4>) based on speed electromotive force estimation is performed. However, at the time of deceleration, only position estimation (<2.4>) based on speed electromotive force estimation is performed at 80 rpm or more.

<4.2> Operating Area Measurement Results FIG. 10 shows the operating area measurement results during sensorless operation.
The torque is slightly smaller than the required operation region in FIG.

<4.3> Step Response An actually measured torque response when a torque command on a step was given was measured. The result is shown in FIG. However, a ramp limit process is performed on the torque command, and it takes 1.64 seconds to reach the maximum torque command.

5. Consideration The cause of the decrease in torque in sensorless operation is considered to be a position estimation error. During high-speed rotation, a large amount of field weakening current Id flows to cancel the induced voltage. For example, when rotating at 4350 rpm, a field-weakening current of Id = 300 A, which is about 11 times the torque current Iq = 27 A, is flowing. In the case of such a current phase, if the position estimation error is small, the field-weakening current component becomes a torque current component, causing a large torque fluctuation. That is, the higher the speed, the larger the torque error caused by the position estimation error.

In the position estimation during rotation, the current flowing from the previously applied voltage is estimated. However, there is a case where the voltage is not applied as instructed due to the nonlinearity of the controller. Dead time, low battery voltage, IG
The ON voltage of the BT may be considered as the cause.

[0089]

According to the motor rotor position estimating apparatus of the present invention, a low-voltage IPM can be operated up to a high rotation.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an operation of estimating a stationary rotor position of a motor rotor position estimating apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a model of an IPM motor to which an embodiment of the motor rotor position estimating apparatus according to the present invention is applied;

FIG. 3 is a circuit diagram showing a dq-axis equivalent circuit of an IPM motor to which an embodiment of the motor rotor position estimating apparatus according to the present invention is applied;

FIG. 4 is a timing chart showing a current response when a pulse voltage is applied in estimating the rotor position at an extremely low speed in one embodiment of the motor rotor position estimating device of the present invention.

FIG. 5 is a diagram illustrating a rotor position estimation during normal rotation of the motor rotor position estimation device according to one embodiment of the present invention;
FIG. 4 is a block diagram showing a configuration for performing rotor position estimation for speed electromotive force estimation.

FIG. 6 is a block diagram showing a configuration for performing current control of an IPM motor in one embodiment of the motor rotor position estimating apparatus of the present invention.

FIG. 7 is a diagram schematically showing a test device for performing a test in one embodiment of the motor rotor position estimating device of the present invention.

FIG. 8 is a diagram showing required driving characteristics of a motor to which an embodiment of the motor rotor position estimating device of the present invention is applied.

FIG. 9 is a diagram showing a position estimation test result during sensorless operation in one embodiment of the motor rotor position estimation device of the present invention.

FIG. 10 is a diagram showing an operation area measurement result during sensorless operation in one embodiment of the motor rotor position estimating device of the present invention.

FIG. 11 is a diagram showing a result of measuring an actually measured torque response when a torque command on a step is given in one embodiment of the motor rotor position estimating device of the present invention.

FIG. 12 is a block diagram showing a detailed configuration of a speed / position estimating unit in one embodiment of the motor rotor position estimating device of the present invention.

FIG. 13 is a diagram showing position estimation performed according to the number of rotations of the motor in one embodiment of the motor rotor position estimation device of the present invention.

FIG. 14 is a diagram showing a position estimation error at an extremely low speed in one embodiment of the motor rotor position estimation device of the present invention.

FIG. 15 is a diagram showing constants of a motor to which an embodiment of the motor rotor position estimating apparatus according to the present invention is applied;

[Explanation of symbols]

13 Inverter 14 IPM Motor 21 Optimum Current Table 23 Voltage Command Calculator 24 3-Phase / 2-Phase Converter 25 Virtual Model in Controller 26 2-Phase / 3-Phase Converter 29 Low-Speed Position Estimator 30 Position / Speed Estimation Algorithm 31 Speed Start Power estimation unit 32 Speed error estimation unit 33 LPF 34 Speed estimation unit 35 Position estimation unit 41 Speed / position estimation unit 51 Electromotive force constant correction unit T ^* Torque command

Continued on the front page F-term (reference) 3L061 BE02 5H560 AA02 AA08 BB04 BB17 DA10 DA14 DB14 DC12 EB01 EC01 GG04 HC02 RR05 SS01 TT12 TT15 UA02 XA02 XA04 XA08 XA13 5H576 AA10 AA15 BB10 CC01 DD02 DD07 FF01 GG02 JJ03 JJ06 JJ23 JJ24 KK06 LL14 LL22 LL40 LL41

Claims (21)

[Claims] 1. A position estimation device of a motor rotor provided with a position estimation unit for estimating the position of the rotor of the motor, the position estimating unit, based on the speed electromotive force constant K _E of the motor, The position of the rotor is estimated, and the speed electromotive force constant K _E is calculated by the following equation.
_EM (n) Here, the K _EM (n-1) is the speed electromotive force constant before the position of the rotor is estimated.
_k is an electromotive force constant estimation gain, Δiγ is a difference between an estimated current estimated to be detected from the motor and an actual current actually flowing in the motor, and α is a sufficiently small value. A motor rotor position estimating device. 2. A motor rotor position estimating device including a position estimating unit for estimating a position of a motor rotor, wherein the position estimating unit estimates a speed electromotive force of the motor,
Based on the estimated speed electromotive force and the speed electromotive force constant K _E of the motor to estimate the position of the rotor, the speed electromotive force constant K _E is obtained by the following equation K
_EM (n) Here, the K _EM (n-1) is the speed electromotive force constant before the position of the rotor is estimated.
_k is an electromotive force constant estimation gain, Δiγ is the difference between the estimated current estimated to be detected from the motor and the actual current actually flowing through the motor, and α is the sigmoid function. A motor rotor position estimating device that is a gain and a sufficiently small value. 3. The motor rotor position estimating device according to claim 1, wherein the term K _k Δiγ in the equation has a fast response, and the term αsgn (Δiγ) has a slow response. Estimating device for motor rotor. 4. The motor rotor position estimating device according to claim 1, wherein the term αsgn (Δiγ) has a time constant of 10 seconds or more. Position estimation device. 5. The motor rotor position estimating device according to claim 1, wherein the motor is an IPM motor. 6. The motor rotor position estimating device according to claim 1, wherein (maximum torque speed: maximum speed) of the motor is (1:
8) The apparatus for estimating the position of the motor rotor as described above. 7. A motor rotor position estimating device for estimating a rotor position θ _M of a motor, wherein a current detected from the motor is estimated based on an applied voltage applied to the motor. A current estimating unit for estimating as a current, a current detecting unit for detecting an actual current actually flowing to the motor by the applied voltage before the estimated current is estimated, based on the estimated current and the actual current, A position estimating unit for estimating the position θ _M of the rotor, wherein the position estimating unit calculates the position θ _{M of the} rotor by the following equation.
, And Here, the θ _M (n) is the estimated position of the rotor θ _M , the θ _M (n−1) is the position of the rotor before the estimation, T is the cycle when the current is controlled, K _E is the speed electromotive force constant of the motor, e _M (n) is the estimated speed electromotive force, and Z is , A correction amount of the position estimation error, and the K _E in the above equation is K _EM obtained by the following equation.
(N) is substituted. Here, the K _EM (n−1) is the speed electromotive force constant before the estimation, the K _k is an electromotive force constant estimation gain, and the Δiγ is the estimated current and the actual current. The motor rotor position estimating apparatus, wherein the difference is a current, and the α is a sufficiently small value. 8. The motor rotor position estimating apparatus according to claim 7, wherein said Z is obtained by the following equation. Here, the K _θ is a position estimation gain, and the ω _M0
(N−1) is the speed of the rotor before the estimation, and the Δi _γ (n) is the difference between the estimated current and the actual current. 9. The motor rotor position estimating apparatus according to claim 8, wherein the Δi _γ (n) is a difference between the d-axis current as the actual current and the γ-axis current as the estimated current. Rotor position estimation device. 10. The motor rotor position estimating apparatus according to claim 1, wherein Δiγ is a difference between the d-axis current as the actual current and the γ-axis current as the estimated current. A motor rotor position estimating device. 11. The motor rotor position estimating apparatus according to claim 2, wherein the estimated speed electromotive force e _M (n) is obtained by the following equation. Here, the e _{M (n-1)} is a speed electromotive force prior to the estimated, the K _e is the estimated speed electromotive force gain, the Δi δ _(n), the estimated current and An apparatus for estimating a position of the motor rotor, which is a difference between the actual currents. 12. The motor rotor position estimating apparatus according to claim 11, wherein Δi _δ (n) is a difference between the q-axis current as the actual current and the δ-axis current as the estimated current. Child position estimation device. 13. The motor rotor position estimating device according to claim 1, wherein the position estimating unit is configured to control the rotation of the rotor regardless of the number of rotations of the motor during operation of the motor. Position estimating device for estimating the position of the motor rotor. 14. The motor rotor position estimating device according to claim 1, wherein the position estimating unit includes a U, V, and W-phase winding of the motor when the motor is stationary. And applying a pulse voltage of the same magnitude to each of the U, V, and W phase windings, comparing the magnitudes of currents flowing through the respective windings, and estimating the position of the rotor based on the result of the comparison. Child position estimation device. 15. The motor rotor position estimating device according to claim 1, wherein the position estimating unit superimposes a pulse voltage on a d-axis command voltage when the motor is at a low speed, A motor rotor position estimating device for estimating a difference between the estimated rotor position and an actual rotor position based on a current change amount at that time. 16. The motor rotor position estimating device according to claim 1, wherein the maximum torque of the motor is 125 [Nm], and the maximum rotation speed of the motor is 4350 [rpm]. A motor rotor position estimating device. 17. A motor to which the motor rotor position estimating device according to claim 1 is applied. 18. An electric vehicle to which the motor according to claim 17 is applied, wherein a limited low voltage of a battery mounted on the electric vehicle is used as a power source of the motor. 19. An air conditioner to which the motor according to claim 17 is applied. 20. A motor rotor position estimating method for estimating a position of a rotor of a motor, the method comprising: (a) estimating a position of the rotor based on a speed electromotive force constant K _E of the motor; And (b) the speed electromotive force constant K _E
Comprises the step of executing (a) assuming that K _EM (n) is determined by the following equation: Here, the K _EM (n-1) is the speed electromotive force constant before the position of the rotor is estimated.
_k is an electromotive force constant estimation gain, Δiγ is a difference between an estimated current estimated to be detected from the motor and an actual current actually flowing in the motor, and α is a sufficiently small value. Is a method for estimating the position of the motor rotor. 21. A program for causing a computer to execute each step of the motor rotor position estimating method according to claim 20.