JP4437401B2 - Speed sensorless motor controller - Google Patents

Description

  The present invention relates to torque control of an electric motor. In particular, the present invention relates to high-precision estimation of the initial speed and initial secondary magnetic flux of the electric motor and high-precision motor torque control.

FIG. 4 is a block diagram showing a conventional example. In the same figure, an example of pick-up control of the electric motor 6 will be described. 1 is a torque control means, 2 is a pick-up control means, 3 is a switch, 4 is a power converter, 5 is a current detector, 6 is an electric motor, and 7 is an initial value estimator.
The current detector 5 detects a current vector i flowing through the electric motor 6. The pick-up control means 2 inputs the current vector i detected by the current detector 5 and outputs a pick-up voltage command v0 that makes the current i flowing through the electric motor 6 a direct current.

  The initial value estimator 7 receives a current vector i, a pick-up voltage command v0, a pick-up control start command ST, and a primary resistance R1, and outputs an initial speed ωm0 and an initial secondary magnetic flux φ20.

  When the torque control start command SW is set, the torque control means 1 sets the torque of the electric motor 6 based on the current vector i using the initial speed ωm0 and the initial secondary magnetic flux φ20, which are outputs of the initial value estimator 7, as initial values. A torque control voltage command V1 to be controlled is output.

The switch 3 switches between the pick-up voltage command v0 and the torque control voltage command V1 by the torque control start command SW. That is, until the torque control start command SW is set, the pick-up voltage command v0 is set as the voltage command V *, and when the torque control start command SW is set, the torque control voltage command V1 is output as the voltage command V *.
The power converter 4 amplifies the voltage command V * and supplies power to the electric motor 6 (see, for example, Patent Document 1).

With the above configuration, the initial speed ωm0 and the initial secondary magnetic flux φ20 of the motor 6 are estimated by the pick-up control means 2 and the initial value estimator 7 until the torque control start command SW is established. When the torque control start command SW is issued, the torque control of the electric motor 6 is performed using the initial speed ωm0 and the initial secondary magnetic flux φ20 at the time when the SW is raised as initial values.
The timing at which the torque control start command SW is set is determined from the pick-up control time, the initial speed ωm0, and the state of the initial secondary magnetic flux φ20.

  Hereinafter, the pickup control until the torque control start command SW is set will be described in detail.

As shown in FIG. 5, one configuration of the pick-up control means 2 is a current control that outputs a pick-up voltage command v0 for controlling the current flowing to the motor 6 from the direct current command I, the current phase angle θ, and the current vector i to direct current. There is what comprises the means 8.
The initial value estimator 7 estimates the initial speed ωm0 and the initial secondary magnetic flux φ20 of the electric motor 6 from the movement of the pick-up voltage command v0. FIG. 6 is a configuration example of the initial value estimator 7. 9 is an actual magnetic flux estimator, 10 is an actual magnetic flux memory, 11 is an actual magnetic flux extractor, 12 is an initial speed estimator, 13 is an initial magnetic flux estimator, and 14 is an arithmetic timer.

ここで、Ｌ１は一次自己インダクタンス、Ｌ２は二次自己インダクタンス、Ｍは相互インダクタンスである。 The arithmetic timer 14 is a timer counter that is cleared to 0 at the edge of the pick-up control start command ST, and outputs a pick-up time t0. The actual magnetic flux estimator 9 calculates the actual magnetic flux estimation vector φ2r by the equation (A) from the current vector i, the picked-up voltage command v0, and the primary resistance R1.

Here, L1 is a primary self-inductance, L2 is a secondary self-inductance, and M is a mutual inductance.

  The real magnetic flux memory 10 stores the 0 to t0 section of the real magnetic flux estimation vector φ2r that changes every moment. The actual magnetic flux extractor 11 extracts the values φ (t00), φ (t01), and φ (t02) of the actual magnetic flux estimation vector φ2r at arbitrary three points in time from 0 to t0.

ここで、（Ｆ１Ａ、Ｆ１Ｂ）、（Ｆ２Ａ、Ｆ２Ｂ）、（ＲＡ、ＲＢ）は、各々、Ｆ１、Ｆ２、Ｒの各成分である。
次に、円の中心Ｒから見たφ（ｔ００）とφ（ｔ０２）の角度θＣを式（Ｆ）で求める。

As an example, the initial speed estimator 12 calculates the initial speed ωm0 using Expressions (B) to (G). First, the center R of a circle passing through the three points is obtained by Expressions (B) to (E).

Here, (F1A, F1B), (F2A, F2B), and (RA, RB) are components of F1, F2, and R, respectively.
Next, an angle θC between φ (t00) and φ (t02) viewed from the center R of the circle is obtained by the equation (F).

ここで、ｊは虚数単位、Ｔ２は二次時定数で、Ｌ２／Ｒ２で得られる。Ｒ２は二次抵抗である。 The initial magnetic flux estimator 13 obtains the initial secondary magnetic flux φ20 by the equation (H).

Here, j is an imaginary unit, T2 is a second-order time constant, and is obtained by L2 / R2. R2 is a secondary resistance.

The above pick-up technique has the following problems.
If there is an error in the primary resistance R1 due to fluctuations in the motor temperature or the like, the error in the calculated magnetic flux vector φ2r, which is the output value of the actual magnetic flux calculator 9, is accumulated by the equation (A). As a result, there are errors in φ (tx0), φ (tx1), and φ (tx2) that are the outputs of the actual magnetic flux extractor 11. An error occurs in the initial velocity ωm0 and the initial secondary magnetic flux φ20 estimated by the equations (B) to (H) based on φ (tx0), φ (tx1), and φ (tx2).

  As described above, if there is an error in the primary resistance, an error occurs in the initial speed ωm0 and the initial secondary magnetic flux φ20, and the initial value of the torque control means 1 has an error. Can not.

Therefore, 21 to 25 in FIG. 4 are added so that the primary resistance R1 of the formula (A) can be estimated. Hereinafter, 21 to 25 in FIG. 4 will be described.
In FIG. 4, 21 is an identification timer, 22 is a magnetic flux calculator, 23 is a magnetic flux memory, 24 is a magnetic flux extractor, and 25 is an R1A identifier.

The identification timer 21 is a timer counter that is cleared to 0 at the edge of the pick-up control start command ST, and outputs an identification time tx. The magnetic flux calculator 22 calculates the calculated magnetic flux vector φ2s from the current vector i, the pick-up voltage command v0, and the primary resistance nominal value R1C according to the equation (I).

The calculation magnetic flux memory 23 stores a 0 to tx section of the calculation magnetic flux vector φ2s that changes every moment. The calculation magnetic flux extractor 24 extracts values φs (tx0), φs (tx1), and φs (tx2) of the calculation magnetic flux vector φ2s at three equal intervals from the 0 to tx interval. In particular, let tx2 be the identification time tx.
tx0 = tx1-tx0 = tx-tx1 Formula (J)
Put it.

  The R1A identifier 25 receives φs (tx0), φs (tx1), φs (tx2), the identification time tx, the current vector i, and the primary resistance nominal value R1C, and outputs the primary resistance R1. Hereinafter, the R1A identifier 25 will be described.

In the formula (I), it is assumed that the primary resistance nominal value R1C is deviated from the true value R1 by an error ΔR.
R1 = R1C + ΔR Formula (K)
When the formula (K) is substituted into R1C of the formula (I), the current vector i is constant, so the formula (I) is expressed by the formula (L) using the formula (A).
φ2s = φ2r + ΔR · i · t Formula (L)
Here, t is the calculation time of φ2s. Further, L2≈M.

ここで、Ｅ０ＡとＥ０ＢはＥ０をΔＲについてまとめた場合の係数である。 Therefore, E0 is calculated by the equations (M) to (O).

Here, E0A and E0B are coefficients when E0 is summarized for ΔR.

Since φ2r draws a circle, the origin, FS1, and FS2 are on the same circle. Furthermore, since the origin, FS1, and FS2 are sampled at equal intervals, E0 becomes zero. Here, the primary resistance error ΔR can be obtained by the equation (P) that satisfies E0 = 0, but the denominator of the equation (P) may be 0, and at this time, the primary resistance R1 becomes indefinite. Therefore, the primary resistance R1 is identified using integration instead of direct calculation from the equation (P).
ΔR = −E0A / E0B Formula (P)

ここで、ＧＲ１Ａは同定ゲイン、Ｂ０は前回演算時のΔＲ値である。なお、ｔ＝０でＢ０＝０とする。
以下、式（Ｋ）で一次抵抗Ｒ１を得ることができる。 The integral identification method is represented by formula (Q) to formula (S).

Here, GR1A is the identification gain, and B0 is the ΔR value at the previous calculation. Note that t = 0 and B0 = 0.
Hereinafter, the primary resistance R1 can be obtained by the formula (K).

By newly adding the R1 identification functions 21 to 25, it is possible to identify the fluctuation of the primary resistance R1 and to obtain the actual magnetic flux estimation vector φ2r estimated by the real magnetic flux estimator 9 with high accuracy. As a result, the initial speed ωm0 and the initial secondary magnetic flux φ20 of the electric motor 6 can be estimated with high accuracy, and the electric motor torque can be controlled with high accuracy.
JP2001-211697

The prior art has the following problems.
In the formula (P), the primary point of the invention was to obtain the primary resistance error ΔR.
・ E0B, the denominator of formula (P), may be 0.
E0A and E0B are small when residual magnetic flux is present at startup or when the motor speed is high, or when the relative vector between φs (tx0) and φs (tx2) is substantially parallel to the current vector i. For this reason, the calculation accuracy may be significantly deteriorated. At this time, an error occurs in the initial speed ωm0 and the initial secondary magnetic flux φ20, and the initial value of the torque control means 1 has an error, so that the torque control of the electric motor 6 cannot be performed with high accuracy.

Further, in the means for integrating and identifying ΔR in the equations (Q) to (S), the identification time tx is tx> 2π / ωmr equation (T) before ΔR converges.
Then, even if ΔR converges to a true value, there is a possibility that an error of 2nπ may appear in θC according to equation (F). Therefore, if the integral identification calculation is stopped before the expression (T) is satisfied or the identification gain GR1A is increased, ΔR may not converge to the true value or may diverge. Then, an error occurs in the initial speed ωm0 and the initial secondary magnetic flux φ20. Here, ωmr is the actual speed of the electric motor 6, and n is an arbitrary integer other than zero.

If an error occurs in the initial speed ωm0 and the initial secondary magnetic flux φ20, the initial value of the torque control means 1 has an error, so that the torque control of the electric motor 6 cannot be performed with high accuracy. If the errors in the initial speed ωm0 and the initial secondary magnetic flux φ20 become large, the torque control of the electric motor 6 may become impossible.
The present invention has been made to solve the above problems.

In order to solve the above problems, the following configuration is adopted.
(1) A current detector 5 for detecting a current vector i flowing through the electric motor 6
(2) Pick-up control means 2 for inputting a current vector i and outputting a pick-up voltage command v0 for causing a direct current to flow through the motor 6.
(3) An initial value estimator 7 for inputting the current vector i, the pick-up voltage command v0, the primary resistance R1, and the pick-up control start command ST and outputting the initial speed ωm0 and the initial secondary magnetic flux φ20.
(4) Identification timer 21 for counting up identification time tx by pick-up control start command ST
(5) A magnetic flux calculator 22 for inputting a current vector i, a pick-up voltage command v0 and a primary resistance nominal value R1C and outputting a calculated magnetic flux vector φ2s.
(6) Rotating coordinate converter 32 for rotating the coordinate of the calculated magnetic flux vector φ2s in the current axis direction θ and outputting the rotating magnetic flux vector φ2t.
(7) An extreme magnetic flux extractor 30 that outputs an extreme magnetic flux vector φt1 and an extreme time tx3 when the rotating magnetic flux vector φ2t becomes an extreme value.
(8) An R1B identifier 31 that inputs an extreme magnetic flux vector φt1, an extreme time tx3, and a current vector i and outputs a primary resistance R1.

  With the above configuration, the primary resistance fluctuation ΔR can be identified with high accuracy. As a result, the initial speed ωm0 and the initial secondary magnetic flux φ20 of the electric motor 6 can be estimated with high accuracy, and the motor torque can be accurately determined. Can be controlled.

  The primary resistance fluctuation ΔR can be identified with high accuracy. As a result, the initial speed ωm0 and the initial secondary magnetic flux φ20 of the electric motor 6 can be estimated with high accuracy, and the motor torque can be controlled with high accuracy. .

  By identifying the primary resistance fluctuation ΔR with high accuracy, the motor torque is controlled with high accuracy.

  FIG. 1 is a block diagram showing an embodiment of the present invention, in which 32 is a rotary coordinate converter, 30 is an extreme magnetic flux extractor, and 31 is an R1B identifier.

The rotating coordinate converter 32 receives the calculated magnetic flux vector φ2s and the current phase angle θ, and calculates the rotating magnetic flux vector φ2t using the equations (U) and (V).
F2tA = F2sA · cosθ + F2sB · sinθ Formula (U)
F2tB = −F2sA · sinθ + F2sB · cosθ Formula (V)
Here, (F2sA, F2sB) and (F2tA, F2tB) are components of φ2s and φ2t, respectively. Applying equation (L) to φ2s,
F2tA = F2rtA + ΔR · I · t Formula (W)
F2tB = F2rtB Formula (X)
It becomes. Here, (F2rtA, F2rtB) are components when the actual magnetic flux estimation vector φ2r is subjected to rotational coordinate conversion in the θ direction. By passing the rotary coordinate converter 32, the effect of the primary resistance error ΔR is only F2tA, and the effect of the primary resistance error ΔR is eliminated in F2tB.

  As shown in FIGS. 2 and 3, the extreme magnetic flux extractor 30 extracts an extreme magnetic flux vector φt1 that is a φ2t value at the maximum and minimum points of F2tB and a time tx3 at the maximum and minimum points of F2tB. 2 and 3 (F2A1, F2B1) are components of φt1.

From the tx3 extracted by the extreme value magnetic flux extractor 30, and φt1 = (F2A1, F2B1), the R1B identifier 31
ΔR = F2A1 / I / tx3 Formula (Y)
R1 = R1C + ΔR Formula (Z)
To identify R1.

The reason why the primary resistance error ΔR is obtained by the equation (Y) is shown below.
Since (F2rtA, F2rtB) in the expressions (W) and (X) are sine waves having a phase difference of 90 degrees, if F2rtB is the maximum or minimum, F2rtA = 0 is always obtained. Therefore, at t = tx3, the equation (W) is expressed as: F2A1 = ΔR · I · tx3 Equation (AA)
It becomes. Expression (Y) is derived from Expression (AA).

Since neither I nor tx3 is 0, the calculation accuracy is not deteriorated by the equation (Y). Further, unless the direct current command I is made very small, the denominator and numerator of the formula (Y) are never small.
According to the present invention, since R1 can be identified in a half cycle of the motor speed, the formula (T) does not hold.

However, if there is a residual magnetic flux at the start and the residual magnetic flux cannot be estimated in equation (I), the direct current component is loaded on F2A1 due to the direct current component on φ2s. Don't be. In order to solve this problem, extreme magnetic flux vector values at different times are used. That is, from the time tx31 and the extreme magnetic flux vector (F2A11, F2B11) when F2tB is maximized, the time tx32 and the extreme magnetic flux vector (F2A12, F2B12) when F2tB is minimized,
ΔR = (F2A11−F2A12) / I / (tx31−tx32) Formula (AB)
Then, the primary resistance error ΔR is obtained. Due to the difference between the two points, the influence of the direct current component on F2A1 can be eliminated.
In selecting tx31 and tx32, it is obvious that the formula (AB) holds even when both of the two points are the maximum time point of F2tB and the minimum time point of F2tB.

According to equation (AB), one period of motor speed is required for R1 identification.
t00 = tx31 Formula (AC)
t02 = tx32 Formula (AD)
Assuming that the R1 identification value according to the formula (AB) is used, the estimation error of the initial speed ωm0 does not occur. Note that tx31 <tx32, and tx32 is the extreme time immediately after tx31.

  With the above configuration, the primary resistance fluctuation ΔR can be identified with high accuracy. As a result, the initial speed ωm0 and the initial secondary magnetic flux φ20 of the motor 6 can be estimated with high accuracy, and the motor torque can be estimated. It can be controlled with high accuracy.

Even without a speed sensor, the coasting speed at the start of operation of the electric motor can be estimated quickly and with high accuracy.
For example, in speed sensorless vehicle control, re-acceleration from the coasting traveling state and braking from the coasting traveling state are possible.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing a calculation example of the extreme magnetic flux extractor of the present invention. FIG. 3 is a diagram showing a calculation example of the extreme value magnetic flux extractor of the present invention. FIG. 4 is a block diagram showing a conventional example. FIG. 5 is a block diagram showing an example of the configuration of the pick-up control means of one conventional example. FIG. 6 is a block diagram showing a configuration example of an initial value estimator of a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque control means 2 Pickup control means 3 Switch 4 Power converter 5 Current detector 6 Electric motor 7 Initial value estimator 8 Current control means 9 Real magnetic flux estimator 10 Real magnetic flux memory 11 Actual magnetic flux extractor 12 Initial speed estimator 13 Initial magnetic flux estimator 14 Operation timer 21 Identification timer 22 Magnetic flux calculator 23 Operation magnetic flux memory 24 Operation magnetic flux extractor 25 R1A identifier 30 Extreme value magnetic flux extractor 31 R1B identifier 32 Rotating coordinate converter

v0 ... Pickup voltage command
V1 ... Torque control voltage command V * ... Voltage command i ... Current vector ωmr ... Actual speed SW ... Torque control start command ST ... Pick-up control start command R1 ... Primary resistance ωm0 ... Initial speed φ20 ... Initial secondary magnetic flux I ... DC current command θ ... Current command phase angle t0 ... Pickup time φ (t0) ... Actual magnetic flux estimation vector at time t0 t00, t01, t02 ... any value between 0 and t0 φ (t00) ... actual magnetic flux estimation vector at time t00 φ (t01) ... real magnetic flux estimation vector at time t01 φ (t02) ... t02 Actual magnetic flux estimation vector at the time φ2r ・ ・ ・ Real magnetic flux estimation vector
t00, t01, t02 ... Arbitrary values within the pick-up time tx ... Identification time φ2s ... Computed magnetic flux vector R1C ... Primary resistance nominal value ΔR ... Primary resistance error φs (tx) ... Calculated magnetic flux vector at time tx
tx0, tx1, tx2 ... any value between 0 and tx φs (tx0) ... computed magnetic flux vector at time tx0 φs (tx1) ... computed magnetic flux vector at time tx1 φs (tx2) ... tx2 Calculated magnetic flux vector at the time φ2t ・ ・ ・ Rotary magnetic flux vector φt1 ・ ・ ・ Extreme magnetic flux vector
tx3: Extreme time F2A1: θ direction component of φt1 at time tx3 F2B1: θ direction orthogonal component of φt1 at time tx3
tx31 ・ ・ ・ Extreme time 1
F2A11 ... θ direction component of φt1 at time tx31 F2B11 ... θ direction orthogonal component of φt1 at time tx31
tx32 ・ ・ ・ Extreme time 2
F2A12: θ direction component of φt1 at time tx32 F2B12: θ direction orthogonal component of φt1 at time tx32

Claims (1)

A current detector for detecting a current vector flowing in the motor, a pick-up control means for inputting the current vector and outputting a pick-up voltage command for passing a DC current to the motor, pick-up of the current vector, the pick-up voltage command, and a primary resistance An initial value estimator for inputting a control start command and outputting an initial speed and an initial secondary magnetic flux, an identification timer for counting up an identification time tx by the pick-up control start command, the current vector and the pick-up voltage command A magnetic flux calculator that inputs a primary resistance nominal value and outputs a calculated magnetic flux vector, a calculated magnetic flux memory that stores the calculated magnetic flux vector at time tx, and extracts a calculated magnetic flux vector at any time point from the calculated magnetic flux memory. A magnetic flux extractor, the magnetic flux vector at any time and the current vector In speed sensorless motor control apparatus having R1A identifier for outputting a primary resistance,
The current detector, the pick-up control means, the initial value estimator, the identification timer, the magnetic flux calculator, and a rotational coordinate conversion of the computed magnetic flux vector in the direction of the current axis to output a rotational magnetic flux vector A rotary coordinate converter, an extreme magnetic flux extractor that outputs an extreme magnetic flux vector and an extreme time tx3 when the rotational magnetic flux vector becomes an extreme value, the extreme magnetic flux vector, the extreme time tx3, and the A speed sensorless motor control device comprising: an R1B identifier that inputs a current vector and outputs the primary resistance.

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