JP6953302B2 - Speed sensorless motor controller - Google Patents

Description

The present invention relates to torque control of a motor, and in particular, provides a motor control device capable of highly accurate estimation of the initial speed and initial secondary magnetic flux at the time of starting the motor and starting motor torque control with high accuracy. be.

A so-called speed sensorless motor control device, which is not provided with a speed sensor, is known from the viewpoint of improving the maintainability of the motor and obtaining a large output even if the motor is made smaller. When controlling the torque of a motor with such a speed sensorless motor control device, it is generally necessary to estimate the speed (angular velocity) of the motor.

FIG. 6 is a block diagram showing a configuration example of a conventional speed sensorless motor control device (see, for example, Patent Documents 1 and 2). The current detector 5 detects the current vector i flowing through the motor 6. The pick-up control unit 2 inputs the current vector i detected by the current detector 5, the DC current command I and the DC phase angle command θ, and sets the current vector i flowing through the motor 6 as the command (I, θ). Outputs the pick-up voltage command v0.

ここで、Ｒ１は電動機６の一次抵抗、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 real magnetic flux estimator 9 calculates the real magnetic flux vector φ2r of the motor 6 by the equation (A) from the current vector i and the pick-up voltage command v0.

Here, R1 is the primary resistance of the motor 6, L1 is the primary self-inductance, L2 is the secondary self-inductance, and M is the mutual inductance.

The calculation timer 14 is a timer counter that is cleared to 0 at the edge of the pick-up control start command ST, and outputs the pick-up time t0. The initial value estimator 7 inputs the current vector i, the actual magnetic flux vector φ2r, and the pick-up time t0, and outputs the initial velocity ωm0 of the motor 6 and the initial secondary magnetic flux φ20.

When the torque control start command SW is turned on, the torque control unit 1 sets the initial speed ωm0, which is the output of the initial value estimator 7, and the initial secondary magnetic flux φ20 as initial values, and based on the current vector i, the torque of the motor 6 The torque control voltage command V1 for controlling the above is output.

The switch 3 switches and outputs the pick-up voltage command v0 and the torque control voltage command V1 by the torque control start command SW. That is, the pick-up voltage command v0 is set as the voltage command V * until the torque control start command SW is turned on, and the torque control voltage command V1 is output as the voltage command V * when the torque control start command SW is turned on. The power converter 4 amplifies the voltage command V * and supplies electric power to the motor 6.

With the above configuration, until the torque control start command SW is turned on, the pick-up control unit 2, the actual magnetic flux estimator 9, the calculation timer 14, and the initial value estimator 7 use the initial speed ωm0 of the motor 6 and the initial speed. The secondary magnetic flux φ20 is estimated. When the torque control start command SW is turned on, the torque control of the motor 6 is performed with the initial speed ωm0 at the time when the SW is turned on and the initial secondary magnetic flux φ20 as initial values. The timing for turning on the torque control start command SW is determined by the pick-up control execution time, the initial speed ωm0, the initial secondary magnetic flux φ20, and the like.

Hereinafter, the operation of the initial value estimator 7 in the pick-up control until the torque control start command SW is turned on will be described in detail.

The initial value estimator 7 estimates the initial velocity ωm0 of the motor 6 from the movement of the actual magnetic flux vector φ2r, and estimates the initial secondary magnetic flux φ20. FIG. 7 is a configuration example of the initial value estimator 7.

The real magnetic flux memory 10 stores the section from the time 0 to the pick-up time t0 of the real magnetic flux vector φ2r that changes from moment to moment. The actual magnetic flux extractor 11 extracts φ (t00), φ (t01), and φ (t02), which are the actual magnetic flux vectors φ2r at arbitrary three time points t00, t01, and t02, from the interval from time to t0.

As an example, the initial velocity estimator 12 calculates the initial velocity ωm0 by the equations (B) to (G). In this method, first, the center R of the circle passing through the end points of the three vectors φ (t00), φ (t01), and φ (t02) is obtained by the equations (B) to (E).

F1 = φ (t01) −φ (t00) Equation (B)

F2 = φ (t02) −φ (t00) Equation (C)

ここで、（Ｆ１_Ａ、Ｆ１_Ｂ）、（Ｆ２_Ａ、Ｆ２_Ｂ）、（Ｒ_Ａ、Ｒ_Ｂ）は、各々、ベクトルＦ１、Ｆ２、Ｒの各成分である。次に、円の中心Ｒから見た、ベクトルφ（ｔ００）とベクトルφ（ｔ０２）との間の角度θＣを式（Ｆ）で求める。

_{Here, (F1 A, F1 B)} , (F2 A, F2 B), (R A, R B) are each a respective component of the vectors F1, F2, R. Next, the angle θC between the vector φ (t00) and the vector φ (t02) as seen from the center R of the circle is obtained by the equation (F).

ここで、記号「×」はベクトルの外積を、記号「・」はベクトルの内積をそれぞれ示す。
時刻ｔ００からｔ０２まで（例えば数十ミリ秒）のモータの回転速度は、ほぼ一定とみなすことができるため、最後に式（Ｇ）で初期速度ωｍ０を求めることができる。

Here, the symbol "x" indicates the outer product of the vectors, and the symbol "・" indicates the inner product of the vectors.
Since the rotation speed of the motor from time t00 to t02 (for example, several tens of milliseconds) can be regarded as almost constant, the initial speed ωm0 can be finally obtained by the equation (G).

ここで、ｊは虚数単位、Ｔ２は電動機６の二次時定数で、Ｌ２／Ｒ２で得られる。Ｒ２は二次抵抗である。φｘｘは拾い上げ制御開始時の残留磁束である。なお、式（Ｈ）の第２項は、ベクトルＲに対する実磁束ベクトルφ２ｒの相対ベクトルとして求めることもできる。 The initial magnetic flux estimator 13 obtains the initial secondary magnetic flux φ20 by the equation (H) using the current vector i.

Here, j is an imaginary unit, T2 is a secondary time constant of the motor 6, and is obtained by L2 / R2. R2 is a secondary resistor. φxx is the residual magnetic flux at the start of pick-up control. The second term of the equation (H) can also be obtained as a relative vector of the actual magnetic flux vector φ2r with respect to the vector R.

Japanese Unexamined Patent Publication No. 2001-2116889 Japanese Unexamined Patent Publication No. 2001-211697

The prior art has the following problems. When estimating the initial velocity ωm0 of the motor 6 from the movement of the circular locus of the actual magnetic flux vector φ2r using the equations (B) to (G), the second term of the equation (H) when the time t0 changes. It can be considered that the initial velocity ωm0 is estimated using the movement of the part.

In the second term of the equation (H), when there is a residual magnetic flux φxx such that the absolute value in parentheses becomes small, the size of the vectors F1 and F2 is large in the calculation using the equations (B) to (G). As the value is small, the influence of the estimation error of the actual magnetic flux estimator 9 becomes large, and as a result, the calculation accuracy deteriorates, and there is a possibility that an error occurs in the estimation of the initial velocity ωm0 and the initial secondary magnetic flux φ20.

Further, even when the residual magnetic flux φxx = 0 after a while after using the motor, the absolute value in parentheses in the second term of the equation (H) becomes small when the initial speed to be estimated is high. In this case as well, the speed calculation accuracy deteriorates due to the small size of the vectors F1 and F2 in the calculation using the formulas (B) to (G), and there is an error in estimating the initial speed ωm0 and the initial secondary magnetic flux φ20. It can occur.

From the above, especially when there is residual magnetic flux or the initial speed is high, an error occurs in the estimated values of the initial speed ωm0 and the initial secondary magnetic flux φ20, and there is an error in the initial input value of the torque control unit 1. There is a possibility that the torque control of the electric motor 6 cannot be performed with high accuracy.

When the residual magnetic flux φxx = 0, the absolute value in parentheses in the second term of the equation (H) can be increased by increasing the magnitude of the current vector i. However, since the pick-up control is performed when the motor is started, the current vector i suddenly changes significantly from zero, and after that, by continuing a large current, the precision equipment around the motor control device is affected by noise, etc. (hereinafter, this effect is affected. May cause inductive interference). Increasing the current improves the speed calculation accuracy but increases the inductive interference. On the contrary, if the current is reduced, the inductive interference is lowered, but the speed calculation accuracy is lowered. As described above, there is a trade-off relationship between speed calculation accuracy and inductive interference. The present invention has been made to solve the above problems, and is a speed sensorless motor control capable of suppressing inductive interference to a low level and estimating the initial speed ωm0 and the initial secondary magnetic flux φ20 of the motor with high accuracy. The purpose is to provide the device.

In order to solve the above problems, the speed sensorless electric motor control device of the present invention inputs the current detector 5 for detecting the current vector i flowing through the electric motor 6, the current vector i and the pick-up voltage command v0, and inputs the actual magnetic flux vector φ2r. The actual magnetic flux estimator 9 to be output, the initial value estimator 7 for inputting the current vector i, the actual magnetic flux vector φ2r, and the pick-up time t0, and outputting the initial speed ωm0 and the initial secondary magnetic flux φ20 of the electric motor, and the above. The current of the electric motor can be controlled to DC based on the current vector i, a plurality of DC current commands I, and the DC phase angle command θ, and the result of the control is switched by the pick-up control switching command SS to output the pick-up voltage command v0. The pick-up control unit 102 with switching, the pick-up resetting unit 101 that inputs the actual current magnetic current vector φ2r and the DC phase angle command θ and outputs the pick-up control switching command SS, and the pick-up resetting unit 101 When the maximum value of the component of the actual magnetic flux vector φ2r orthogonal to the DC phase angle command θ is detected, the pick-up control switching command SS is turned on, and the pick-up control unit 102 with switching turns on the current vector i. The size of the first current control unit 103 that outputs the first pick-up voltage command v01, which controls the first DC current obtained by the DC current command I and the DC phase angle command θ, and the current vector i. The second current control unit 104 that outputs the second pick-up voltage command v02 that controls the second DC current obtained by the zero DC current command I and the DC phase angle command θ, and the output v01 of the first current control unit. A command switch 106 that switches the output v02 of the second current control unit by the pick-up control switching command SS to set the pick-up voltage command v0 .

By the above means, the magnitude of the absolute value in parentheses in the second term of the equation (H) can be increased, particularly when there is residual magnetic flux or when the initial speed is high. As a result, the initial speed and the initial secondary magnetic flux of the motor can be estimated with high accuracy, and the torque of the motor can be controlled with high accuracy. Further, by reducing the magnitude of the current vector i to zero before the influence of the induced interference spreads to the surroundings, the induced interference can be suppressed to a low level.

FIG. 1 is a block diagram showing a configuration example of a speed sensorless motor control device of the present invention. FIG. 2 is a block diagram showing a configuration example of a pick-up control unit with switching according to the present invention. FIG. 3 is a diagram showing an operation example of the pick-up reset unit of the present invention. FIG. 4 is a diagram showing the locus of the actual magnetic flux vector of the motor when the speed sensorless motor control device according to the embodiment of the present invention is operated. FIG. 5 is a diagram showing an allowable range of timing for turning on the pick-up control switching command SS of the pick-up resetting unit of the present invention. FIG. 6 is a block diagram showing a configuration example of a conventional speed sensorless motor control device. FIG. 7 is a block diagram showing a configuration example of a conventional initial value estimator.

FIG. 1 is a block diagram showing a configuration example of the present invention. The speed sensorless motor control device of the present embodiment includes a current detector 5, an actual magnetic flux estimator 9, an initial value estimator 7, a pick-up control unit 102 with switching, and a pick-up reset unit 101. The same components as those of the prior art shown in FIGS. 6 and 7 described above are designated by the same reference numerals as those in FIGS. 6 and 7, and the description thereof will be omitted. The pick-up control unit 102 with switching can control the current vector i to be a plurality of DC currents having different sizes based on the current vector i of the electric motor 6, the DC current command I, and the DC phase angle command θ (of the electric motor 6). The current can be controlled to direct current), multiple controls are switched by the pick-up control switching command SS, and the pick-up voltage command v0 is output.

The pick-up reset unit 101 inputs the DC phase angle command θ and the actual magnetic flux vector φ2r, and outputs the pick-up control switching command SS. A pick-up control switching command SS is newly input to the calculation timer 14, and the pick-up time t0 is cleared to 0 at the edge (timing) when the pick-up control switching command SS is turned from off to on.

With the above configuration, the pick-up control switching command SS is created according to the state of the actual magnetic flux vector φ2r, and the direct current control state of the pick-up control can be switched by the pick-up control switching command SS.

FIG. 3 is a diagram showing an operation example of the pick-up resetting unit 101 of the present invention. The pick-up reset unit 101 turns on the pick-up control switching command SS when it detects the maximum value of the component of the actual magnetic flux vector φ2r orthogonal to the DC phase angle command θ.

With the above configuration, when the maximum value of the component of the actual magnetic flux vector φ2r orthogonal to the DC phase angle command θ is detected, the output of the pick-up reset unit 101 (DC current control state of pick-up control) is switched. As a result, the pick-up control unit 102 controls so that the magnitude of the direct current of the current vector i is switched.

FIG. 2 is a block diagram showing a configuration example of the pick-up control unit 102 with switching of the present invention. The pick-up control unit 102 with switching includes a first current control unit 103, a second current control unit 104, a multiplier 105, and a command switch 106. The first current control unit 103 inputs the current vector i, the DC current command I, and the DC phase angle command θ, and controls the current vector i flowing through the motor 6 to the first DC current as commanded. Is output.

The multiplier 105 multiplies the DC current command I by zero, sets the DC current command to zero, and outputs the DC current command to the second current control unit 104. The second current control unit 104 inputs the current vector i, the zero DC current command from the multiplier 105, and the DC phase angle command θ, and sets the current vector i flowing through the motor 6 as the second DC current as commanded. 2 The pick-up voltage command v02 is output.

When the pick-up control switching command SS is off, the command switch 106 outputs the first pick-up voltage command v01 as the pick-up voltage command v0. When the pick-up control switching command SS is on, the second pick-up voltage command v02 is output as the pick-up voltage command v0.

Although detailed description is omitted, at least one of the DC current command and the phase angle command input to the second current control unit 104 is the DC current command I and the DC phase angle input to the first current control unit 103. Although there is a possibility that the object of the present invention may be achieved even if the command θ is different from the command θ, as shown in FIG. 2, a zero DC current command and a DC phase angle command θ are input to the second current control unit 104. By configuring the above, the pick-up control unit with switching of the present invention can be realized most effectively.

With the above configuration, the following pick-up control can be realized. For the sake of simplicity, the DC phase angle command θ is set to 0. That is, the first current control unit 103 controls the current vector i to the first direct current (I, 0), and the second current control unit 104 controls the current vector i to the second direct current (0,0).

First, the pick-up control is started from the state where the pick-up control switching command SS is off. The time at this point is set to 0. Since the first pick-up voltage command v01 is output as the pick-up voltage command v0, the current vector i is controlled by the first direct current (I, 0). The locus of the actual magnetic flux vector φ2r of the motor 6 from the start of the pick-up control to the turn-on of the pick-up control switching command SS is shown by, for example, the arc C1 shown in FIG. Here, the solid lines (arcs C1 and C2) in FIG. 4 show the loci when the initial velocity ωm0 is high. Further, the broken lines (arcs C3 and C4) in FIG. 4 show the loci when the initial speed ωm0 is low as described later.

The pick-up reset unit 101 turns on the pick-up control switching command SS when it detects the maximum value of the component of the actual magnetic flux vector φ2r orthogonal to the DC phase angle command θ. _{Since θ = 0 this time, pick-up control is performed at time t 1} when the imaginary axis (B-axis) component of the actual magnetic flux vector φ2r is maximum, that is, when the locus of φ2r intersects the positive side of the B-axis in FIG. The switching command SS is turned on.

After that, since the second pick-up voltage command v02 is output as the pick-up voltage command v0, the current vector i is controlled by the second direct current (0,0). The locus of the actual magnetic flux vector φ2r after the pick-up control switching command SS is turned on is shown by the arc C2 shown in FIG. In the locus of the arc C2, φ (t ₁ ) is the residual magnetic flux φxx represented by the equation (H). Therefore, if the radius of the arc C1 is r, the radius of the arc C2 is 2 * r. Therefore, by switching the pick-up voltage command as described above, the radius of the arc drawn by the actual magnetic flux vector φ2r, that is, the absolute value in parentheses of the second term of the equation (H) can be increased.

In the embodiment shown here, the pick-up control switching command SS is turned on when the maximum value of the imaginary axis component of the actual magnetic flux vector φ2r is detected. As a result, the radius of the arc C2 after switching can be further increased. However, even if the pick-up control switching command SS is turned on within the range shown by the solid line in FIG. 5, the radius of the arc after switching can be increased.

By extracting the values φ (t00), φ (t01), and φ (t02) of the actual magnetic flux vectors φ2r at any three time points from the arc C2 and using the equations (B) to (H), the initial stage of the motor 6 The velocity ωm0 and the initial secondary magnetic flux φ20 can be obtained. As described above, since the radius of the arc C2 is large, the sizes of the vectors F1 and F2 are also large, and the estimation accuracy of the initial velocity ωm0 and the initial secondary magnetic flux φ20 is improved.

From the viewpoint of increasing the magnitude of the vector F1, F2, as shown in FIG. 4, the time _{(t 1)} of the t00 trajectory of φ2r intersects the positive side of the B-axis, the real axis component of φ2r the t01 It is preferable that t02 is set to the minimum time and t02 is set to the time when the locus of φ2r intersects the negative side of the B axis.

By realizing the pick-up control as described above, the absolute value in parentheses in the second term of the equation (H) when the control switching command SS is on can be obtained, and the equation (H) th when the control switching command SS is off. It can be larger than the absolute value in parentheses of the second term.

When the initial speed is high, the time for the first pick-up voltage command v01 to output as the pick-up voltage command v0 is shortened, so that the magnitude of the current vector i is reduced to zero before the influence of the induced interference spreads to the surroundings. Therefore, the induction disorder can be suppressed low.

However, when the initial speed is low, the time for the first pick-up voltage command v01 to output as the pick-up voltage command v0 is not short, so that the influence of inductive interference may appear. Therefore, the pick-up resetting unit 101 does not have to set the predetermined time Tchgm until the pick-up control switching command SS is turned on and detect the maximum value of the component of the actual magnetic flux vector φ2r orthogonal to the DC phase angle command θ. When the predetermined time Tchgm has elapsed, the pick-up control switching command SS is turned on.

The locus of the actual magnetic flux vector φ2r of the motor 6 until the pick-up control switching command SS is turned on is shown by, for example, the arc C3 shown in FIG. The locus of the actual magnetic flux vector φ2r after the pick-up control switching command SS is turned on is shown by the arc C4 shown in FIG. The locus of the actual magnetic flux vector φ2r after the pick-up control switching command SS is turned on is a circular locus whose radius is the magnitude of the actual magnetic flux vector at the moment when the pick-up control switching command SS is turned on.

When the initial velocity is low, the magnetic flux during the off period of the pick-up control switching command SS moves away from the origin quickly, so that the radius of the actual magnetic flux vector φ2r after the pick-up control switching command SS is turned on becomes sufficiently large.

By extracting the values φ (t00), φ (t01), and φ (t02) of the actual magnetic flux vectors φ2r at any three time points from the arc C4 and using the equations (B) to (H), the initial stage of the motor 6 can be obtained. The velocity ωm0 and the initial secondary magnetic flux φ20 can be obtained. As described above, since the radius of the arc C4 is large, the sizes of the vectors F1 and F2 are also sufficient, and the estimation accuracy of the initial velocity ωm0 and the initial secondary magnetic flux φ20 is improved.

Here, if the predetermined time Tchgm is set to a time during which the influence of the induced interference does not appear, the magnitude of the current vector i is reduced to zero before the influence of the induced interference spreads to the surroundings, and the induced interference is lowered. It can be suppressed.

1 Torque control unit 2 Pick-up control unit 3 Switcher 4 Power converter 5 Current detector 6 Electric motor 7 Initial value estimator 9 Real magnetic flux estimator 10 Real magnetic flux memory 11 Real magnetic flux extractor 12 Initial speed estimator 13 Initial magnetic flux estimator 14 Calculation timer 101 Pick-up reset unit 102 Pick-up control unit with switching 103 1st current control unit 104 2nd current control unit 105 Multiplier 106 Command switch

Claims (1)

A current detector that detects the current vector flowing through the motor, and
An actual magnetic flux estimator that inputs the current vector and the pick-up voltage command and outputs the actual magnetic flux vector,
An initial value estimator that inputs the current vector, the actual magnetic flux vector, and the pick-up time, and outputs the initial speed and the initial secondary magnetic flux of the motor.
The current of the motor can be controlled to DC based on the current vector, a plurality of DC current commands, and a DC phase angle command, and the result of the control is picked up by the control switching command and the pick-up voltage command is output. Control unit and
A pick-up resetting unit that inputs the actual magnetic flux vector and the DC phase angle command and outputs the pick-up control switching command.
With
When the pick-up reset unit detects the maximum value of the component of the actual magnetic flux vector orthogonal to the DC phase angle command, the pick-up control switching command is turned on.
The pick-up control unit with switching
A first current control unit that outputs a first pick-up voltage command that controls the current vector to a first DC current obtained by the DC current command and the DC phase angle command.
A second current control unit that outputs a second pick-up voltage command that controls the current vector to a second DC current obtained by a DC current command having a magnitude of zero and the DC phase angle command.
A command switch that switches the output of the first current control unit and the output of the second current control unit by the pick-up control switching command to obtain the pick-up voltage command.
A speed sensorless motor control device characterized by being equipped with.

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