JP2011010486A - Control device for permanent-magnet synchronous machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate the magnet magnetic flux of a permanent-magnet synchronous machine, without being affected by a calculation error of the magnetic pole position.SOLUTION: A permanent-magnet synchronous machine includes an observer that supplies a voltage of a variable voltage and frequency to a motor by a power conversion device so as to detect and estimate a motor current. The permanent-magnet synchronous machine estimates the rotational speed and the magnetic pole position of the motor, by using the detected motor current detection value, at a position sensorless control method for the permanent magnet synchronous machine, the magnet-magnetic flux is estimated, on the basis of an inverse matrix of a transfer function matrix in a range from an error of the magnetic pole position and an error of the magnet magnetic flux which are obtained from a deviation between the motor current detection value and a current estimated value estimated by the observer, up to a deviation between the current detection value and the current estimated value.

Description

  The present invention relates to on-line magnet magnetic flux tuning during position sensorless control of a permanent magnet synchronous machine.

  In the permanent magnet synchronous machine position sensorless control, the torque control accuracy deteriorates due to the setting error of the magnet magnetic flux that fluctuates due to the temperature change. Therefore, on-line tuning technology for magnet magnetic flux has been proposed. As a technique of magnet magnetic flux online tuning at the time of permanent magnet synchronous machine position sensorless control without using a temperature sensor, there is a technique described in Patent Document 1.

FIG. 2 shows a system configuration of a position sensorless control magnet magnetic flux online tuning system configured using the technique described in Patent Document 1.
This system includes a permanent magnet synchronous machine (hereinafter referred to as PMSM) 1, a load 2, a current detection means 3, a power conversion device 4, a rotating two-phase / three-phase coordinate converting means 5, and a three-phase / rotating two-phase coordinate. Conversion means 6, current control means 7, current command value calculation means 8, speed PID adjuster 9, speed estimator 10, motor shaft estimator 11, counter electromotive voltage constant identifier 12, and integration means 13 and a low-pass filter 14.
The three-phase / rotational two-phase coordinate conversion means 6 performs the fixed two-phase conversion of the three-phase current values i _ua , i _va , i _wa output from the current detection means 3 on the α and β axes, and then the output from the integration means 13. Rotational coordinate conversion of the angle is performed and converted into γ and δ axis currents iγ _a and iδ _a which are biaxial quantities.
The axis estimated to be parallel to the magnetic pole of the magnet is the γ-axis, and the direction orthogonal to it is the δ-axis.
Further, the rotating two-phase / three-phase coordinate converting means 5 uses the angle θ _# output from the integrating means 13 to reversely convert the γ and δ-axis voltage command values vγ _a ^* and v δ _a ^* to be fixed. After conversion to a two-phase value, two-phase three-phase conversion is performed to output three-phase voltage command values v _ua ^* , v _va ^* , and v _wa ^* . The voltage command values v _ua ^* , v _va ^* and v _wa ^* are input to the power converter 4. The power conversion device 4 is a power supply device that supplies a voltage current of variable frequency / variable voltage to the motor based on the voltage command values v _ua ^* , v _va ^* , v _wa ^* .
The speed PID controller 9 performs PID calculation on the deviation so that the deviation between the speed command value (electrical angle) ω ^* and the estimated value of the estimated motor speed (electrical angle) ω _# output from the speed estimator 10 becomes zero. The performed value is output as a torque command value _Te ^* .
Current command value calculating unit 8, based on the torque command value received from the speed PID controller 9, gamma, [delta] -axis current value i? _A ^*, created a i? _A ^*.
Current control means 7, gamma received from the current command value computing means 8, [delta] -axis current value iγ _a ^*, iδ _a ^* and, gamma received from the three-phase / rotation two-phase coordinate conversion unit 6, [delta] -axis current i? _a, gamma as i? _a match respectively, [delta] -axis voltage value v? _a ^*, and controls the v? _a ^*.
The speed estimator 10, the speed command value (electric angle) omega ^* and δ-axis current i? _A and the estimated speed from the estimated speed (electrical angle) to obtain the omega _#. The coordinate conversion angle θ _# used in the rotating two-phase / three-phase coordinate converting means 5 and the three-phase / rotating two-phase coordinate converting means 6 is obtained by integrating the estimated speed (electrical angle) ω _# by the integrating means 13. .

The rotational angular velocity of the estimated γδ coordinate is ω _# (electrical angle), the γ axis is on the phase angle of θ _# (electrical angle) from the u phase axis, and Δθ from the axis parallel to the magnetic pole of the magnet (d axis) It is assumed that it is delayed by (electrical angle). The voltage equation of PMSM in γδ coordinates is expressed as (Equation 1).

here,

R _a : Armature winding resistance, L _d , L _q : d, q axis inductance, φ _f : Magnet flux,
_{vγ a, vδ a: γ,} δ -axis _{voltage, iγ a, iδ a: γ} , δ -axis current, omega: rotational angular velocity (electrical angle),
P: Differential operator

In (Equation 1),

Then, the voltage equation of PMSM is expressed as (Equation 5).

The motor shaft estimator 11 estimates the shaft error of the motor from (Equation 5) using (Equation 6).

In the counter electromotive voltage constant identifier 12, the magnetic flux is estimated by (Equation 7) using (Δθ) _# obtained by (Equation 6).

here,

It is also possible to improve the estimation accuracy by using a voltage detector and using γ, δ-axis voltage detection values instead of γ, δ-axis voltage command values in (Equation 6) and (Equation 7). is there.
Φ _# obtained in (Equation 7) is input to the low-pass filter 14, and its output φ _{f #} is input to the current control means 7 and the current command value calculation means 8.

JP 2004-7924 A

However, in the magnetic flux online tuning technique at the time of permanent magnet synchronous machine position sensorless control described in Patent Document 1, when the magnetic pole position calculation error (Δθ− (Δθ) _# ) is not zero during acceleration / deceleration, the magnetic flux estimation is performed. There is a problem that an error occurs.
Therefore, torque control accuracy is deteriorated due to a magnet magnetic flux estimation error.

  Accordingly, an object of the present invention is to estimate the magnetic flux of a permanent magnet synchronous machine without being affected by a magnetic pole position calculation error.

In order to achieve the above object, the invention according to claim 1 includes an observer that applies a variable voltage variable frequency voltage to the motor by the power conversion device, detects the motor current, and estimates the motor current. In the position sensorless control method of the permanent magnet synchronous machine that estimates the rotational speed and magnetic pole position of the motor using the current detection value,
Using the inverse matrix of the transfer function matrix from the magnetic pole position error and magnet magnetic flux error obtained from the deviation between the motor current detection value and the current estimation value estimated by the observer to the deviation between the current detection value and the current estimation value Magnet magnetic flux estimation is performed.

  The magnet flux estimator of the present invention can estimate the magnet flux independently of the magnetic pole position calculation error. Therefore, even when there is a magnetic pole position calculation error, the magnetic flux of the magnet can be estimated with high accuracy, thereby enabling highly accurate torque control.

It is a block diagram which shows embodiment by this invention. It is a block diagram which shows a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention.
In this figure, components having the same functions as those in the conventional configuration shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted here.
The difference from the conventional example shown in FIGS. 1 and 2 is that the speed estimator 10, the motor shaft estimator 11, the counter electromotive voltage constant identifier 12, the integrating means 13, and the low-pass filter 14 are replaced with a current. That is, an observer 21, a magnetic flux estimator 22, and a magnetic pole position / rotation speed estimator 23 are used.

  The current observer 21 for estimating the γ and δ axis currents is the one of (Equation 9).

The current and parameters with # represent estimated values. The parameters that employ the estimated values are θ _# , ω _# , and φf _# . G ₁₁ , g ₁₂ , g ₂₁ , and g ₂₂ are observer gains. It is also possible to improve the estimation accuracy by using a voltage detector and using the detected γ and δ-axis voltage values instead of the γ and δ-axis voltage command values in (Equation 9).
Further, the observer gain is set as shown in (Equation 10).

Here, g _a , g _b , g _c , and g _d are control variables that determine the poles of the observer gain.
Since the characteristic equation of the current observer 21 is as shown in (Equation 11),

Control variables g _a , g _b , g _c , and g _d in the observer gain may be set so that (Equation 11) satisfies the stability condition. The subscript 0 at the lower right indicates the equilibrium point.
Next, the operation of the magnet magnetic flux estimator 22 will be described. The magnet flux estimator 22 calculates (Equation 12).

Where Kφ, x ₁ , x ₀ are estimator gains,

It is.
By transforming (Equation 1), (Equation 14) is obtained.

From (Equation 9), (Equation 10), and (Equation 14),
cosΔθ = cos2Δθ = 1, sinΔθ = Δθ, sin2Δθ = 2Δθ
And linearizing near the equilibrium point, the following linearization error state equation (Equation 15) is obtained. Here, Δω = sΔθ is put in order. In addition, errors in parameters other than the magnetic pole position, rotational speed, and magnet magnetic flux are ignored. Further, vγ _a ^* −vγ _a = 0 and vδ _a ^* −vδ _a = 0. Note that s is a Laplace operator.

here,

From (Equation 15), the linearization error transfer function matrix P ₀ (s) with u as input and e _ia as output is expressed by the following equation (Equation 17).

At this time, from (Equation 12) and (Equation 17),

here,

Is obtained. Since the numerator of the inverse matrix of the linearization error transfer function matrix is used in the estimator of (Equation 12), the 1st row and 1st column of the 1 × 2 matrix on the right side is (0). Therefore, φ _{f #} can be estimated without being affected by the magnetic pole position calculation error Δθ. The estimator gains Kφ, x ₁ and x ₀ are set according to the response of the magnetic flux estimation system from (Equation 18).
The magnetic pole position / rotation speed estimator 23 uses, for example, the following estimator.
The magnetic pole position and rotational speed estimators are represented by the following equations (Equation 20) and (Equation 21).

Here, Kθ ₁ and Kθ ₂ are estimator gains.
Control variables g _b and g _c in the observer gain

By so choosing it as, theta _# and [Delta] [theta], the relationship of [Delta] [phi _f, from (Equation 12) and (Expression 20), the equation (23).

Here, P _D0 = s ² + (g _a0 + g _b0 ) s + (g _a0 g _b0 −g _c0 g _d0 ). From (Equation 23), the estimation of the magnetic pole position is affected by the magnet magnetic flux error. However, since the magnet magnetic flux estimation can be performed independently of the magnetic pole position error and the rotation speed error, The influence of magnetic flux error can be ignored.
The relationship between the time omega _# and [Delta] [omega, [Delta] [phi _f is as (Expression 12), (Expression 21) from equation (24).

From (Equation 24), the estimation of the rotational speed is affected by the magnet magnetic flux error. However, since the magnet magnetic flux estimation can be performed independently of the magnetic pole position error and the rotational speed error, the magnet magnetic flux estimation is converged. The influence of magnetic flux error can be ignored.
The estimator gains Kθ ₁ and Kθ ₂ are set according to the response of the magnetic pole position / rotation speed estimation system from (Equation 23) and (Equation 24).
In addition, you may use another system for estimation of a magnetic pole position and a rotational speed.
Further, the magnet magnetic flux online tuning technology at the time of position sensorless control can be applied to both an embedded magnet type permanent magnet synchronous machine with L _d ≠ L _q and a surface magnet type permanent magnet synchronous machine with L _d = L _q .

  DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2 ... Power converter, 3 ... Positive side feeding circuit, 4 ... Negative side feeding circuit, 5 ... Reference voltage setting circuit, 6 ... Voltage comparison circuit, 7 ... Intermittent signal oscillation circuit, 8 ... E / O Conversion circuit, 9 ... optical cable, 10 ... O / E conversion circuit, 11 ... control circuit, GR1 ... first resistance element group, GR2 ... second resistance element group, GR3 ... third resistance element group, R1P, R2P , R1N, R2N ... voltage dividing resistors, G1G, R2G ... grounding resistors

Claims (1)

A voltage of variable voltage and variable frequency is given to the motor by the power converter,
Detect motor current,
An observer for estimating the motor current,
In the position sensorless control method of the permanent magnet synchronous machine for estimating the rotation speed and the magnetic pole position of the motor using the detected motor current detection value,
Based on the inverse matrix of the transfer function matrix from the magnetic pole position error and the magnetic flux error obtained from the deviation between the motor current detection value and the current estimation value estimated by the observer to the deviation between the current detection value and the current estimation value A method of controlling a permanent magnet synchronous machine, wherein magnet magnetic flux estimation is performed.