JP2009019546A - Variable valve mechanism driving device and valve controlling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of a conventional variable valve mechanism driving device of a valve controlling system in which, because a voltage to be applied to a motor is calculated without considering an induced electromotive force caused by a current change of the motor, a response speed of the motor cannot be made faster and thereby a lift amount cannot be changed at a high speed to an appropriate value for an output of an engine. <P>SOLUTION: A voltage instruction calculator for calculating a voltage instruction value of the motor finds a response current value representing the voltage instruction value of the motor by a delay of first order, and calculates the induced electromotive force caused by the current change of the motor by using the response current value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable valve mechanism driving apparatus that drives a variable valve mechanism that changes the lift amount of an engine valve, and a valve control system that includes the variable valve mechanism driving apparatus.

  A four-stroke engine of an automobile sucks fuel and air into the engine, pushes a piston with a combustion pressure generated by compression and combustion of the mixture, and rotates a tire. After combustion, the gas in the engine is exhausted to the outside.

  The gas circulation in this series of intake, compression, combustion, and exhaust is carried out by an intake valve and an exhaust valve installed at the upper part of the engine, and the opening and closing of these valves greatly affects fuel consumption. The fuel consumption can be improved by changing the lift amount of the valve, and the mechanism for changing the lift amount is a variable valve mechanism.

  Since the optimum lift amount varies depending on the engine output, in order to improve fuel efficiency, it is required that the variable valve mechanism follow the change in the engine output at high speed. In order to satisfy this requirement, the response speed of the motor that drives the variable valve mechanism may be increased.

  Increasing the response speed of the motor can be realized by accurately controlling the rotation angle, angular velocity, and torque of the motor with respect to the command value. The rotation angle and angular velocity of the motor can be achieved by using the actual rotation angle of the motor detected by using the rotation angle sensor and the angular velocity calculated by the detected rotation angle as control parameters. In addition, accurate control of the torque is possible by using the motor current detected by the current sensor as a control parameter because the torque is proportional to the current. As described above, it is desirable to use the rotation angle sensor and the current sensor for accurate control of the rotation angle, angular velocity, and torque of the motor, but it is practically difficult to install both sensors from the viewpoint of cost. Therefore, a variable valve mechanism driving apparatus disclosed in Patent Document 1 has been developed as a variable valve mechanism driving apparatus for a valve control system that does not use an expensive current sensor.

JP2006-200387

  However, in the variable valve mechanism driving device of Patent Document 1, the voltage applied to the motor is calculated without considering the induced electromotive force generated by the change in the motor current. For this reason, even if a voltage obtained based on a rotation angle command value given from the outside is applied to the motor, a response time is required until the motor current reaches a predetermined value. Therefore, there is a problem that the response speed of the motor cannot be increased and the lift amount cannot be changed to a value suitable for the output of the engine at a high speed.

  The present invention has been made in view of the above problems, and is a variable valve of a valve control system that can increase the response speed of a motor and change the lift amount by following a change in engine output at high speed. It is an object to provide a mechanism driving device.

  A variable valve mechanism driving device comprising: a motor that rotationally drives a control shaft of the variable valve mechanism; and a motor control device that controls the motor based on a rotation angle command value of the control shaft given from the outside, A motor control device calculates an angular velocity command value to be given to the motor so that the rotation angle of the control shaft matches the rotation angle command value, and sets the angular velocity of the motor as the angular velocity command value. An angular velocity controller that calculates a current command value to be given to the motor to be matched, and the current command value and the angular velocity of the motor are input, and the resistance voltage of the motor, an induced electromotive force generated by a current change, By calculating the induced electromotive force caused by the steady current and the induced voltage caused by the rotation of the motor A voltage command calculator that outputs a voltage command value of the motor, the voltage command calculator calculates a response current value that represents the current command value of the motor by a first-order lag, and uses the response current value to determine the response current value. We decided to calculate the induced electromotive force generated by the current change of the motor.

  A valve variable mechanism driving device of a valve control system capable of changing the lift amount following high-speed changes in engine output is obtained.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a valve control system according to an embodiment of the present invention. The valve control system shown in FIG. 1 includes a variable valve mechanism 101 and a variable valve mechanism driving device. The variable valve mechanism driving device includes a synchronous motor 108, a rotation angle sensor 104, and a motor control device 100.

  The variable valve mechanism 101 controls the lift amount of the valve in accordance with the rotation angle of the synchronous motor 108, thereby adjusting the intake air amount of the engine. The variable valve mechanism 101 includes a control shaft (not shown) connected to the synchronous motor 108, and the lift amount changes as the swing angle of the cam that drives the valve changes due to the rotational drive of the control shaft. .

A rotation angle sensor 104 serving as a rotation angle detector detects a rotation angle Θs of the control shaft. The motor control device 100 uses a control shaft rotation angle command value Θs * input from the outside in accordance with the depression amount of the accelerator pedal of the automobile and a control shaft rotation angle Θs detected by the rotation angle sensor 104 to make a three-phase operation. An AC voltage is output and the synchronous motor 108 is driven and controlled.

  Next, the configuration of the motor control device 100 will be described. The motor control device 100 includes a rotation angle controller 103, an angular velocity converter 106, an angular velocity controller 105, a voltage command calculator 109, a coordinate converter 110, and an inverter 107.

  The rotation angle controller 103 is a rotation angle control that matches the rotation angle Θs of the control shaft output from the rotation angle sensor 104 with the rotation angle command value Θs * which is a control target value of the rotation angle Θs of the control shaft given from the outside. I do. Specifically, a value obtained by multiplying the difference between the rotation angle command value Θs * and the control shaft rotation angle Θs by a proportional gain is output as the angular velocity command value ω * of the synchronous motor 108.

  The angular velocity converter 106 outputs the angular velocity ω of the synchronous motor 108 using the rotation angle Θs of the control shaft. The angular velocity ω is a value obtained by time-differentiating the rotational angle Θm of the synchronous motor 108 obtained by multiplying the rotational angle Θs of the control shaft by the gear ratio of the gear connecting the synchronous motor 108 and the control shaft.

上記式（１）において、Ｐは同期モータ１０８の回転子の極対数、φは回転子の磁束、Ｋｐは比例ゲイン、Ｋｉは積分ゲインである。
また、電流指令値ｉｄ*は式（２）を用いて算出する。

上記式（２）において、Ｌｄ，Ｌｑは回転二軸座標上のｄ，ｑ軸成分のインダクタンスである。 The angular velocity controller 105 calculates current command values id * and iq * on the rotation biaxial coordinates, and sets the angular velocity command value ω * output from the rotation angle controller 103 to the angular velocity ω output from the angular velocity converter 106. Perform angular velocity control to match. Specifically, the current command value iq * is calculated using Equation (1).

In the above formula (1), P is the number of pole pairs of the rotor of the synchronous motor 108, φ is the magnetic flux of the rotor, Kp is a proportional gain, and Ki is an integral gain.
Further, the current command value id * is calculated using Equation (2).

In the above equation (2), Ld and Lq are the inductances of the d and q axis components on the rotating biaxial coordinates.

  The voltage command calculator 109 uses the current command values id * and iq * output from the angular velocity controller 105 and the angular velocity ω output from the angular velocity converter 106, and uses the d-axis component voltage command values vd * and q. The voltage command value vq * of the shaft component is output.

  Hereinafter, a method of calculating the voltage command value vd * and the voltage command value vq * in the voltage command calculator 109 will be described.

上記、式（３），（４）においてＲ×ｉｄ*、およびＲ×ｉｑ*は抵抗降下分の電圧、（Ｌｄ×ｄ／ｄｔ）×ｉｄ*、および（Ｌｑ×ｄ／ｄｔ）×ｉｑ*は電流変化により生じる誘導起電力、−ωＬｑｉｑ、およびωＬｄｉｄは定常状態の電流により生じる誘導起電力、ωφは回転子磁束による誘導電圧である。 The voltage command values vd * and vq * can be obtained using voltage equations of the following formulas (3) and (4).

In the above formulas (3) and (4), R × id * and R × iq * are the voltage of the resistance drop, (Ld × d / dt) × id *, and (Lq × d / dt) × iq *. Is an induced electromotive force caused by a current change, -ωLqiq and ωLdid are induced electromotive forces caused by a steady-state current, and ωφ is an induced voltage caused by a rotor magnetic flux.

  When the current commands id * and iq * change abruptly, the induced electromotive forces (Ld × d / dt) × id * and (Lq × d / dt) × iq * caused by the current change become excessive, and the voltage command The values vd * and vq * exceed the voltage that the inverter can output. Therefore, the voltage command values vd * and vq * are calculated using the response current values ids and iqs in which the response currents of the current command values id * and iq * are expressed by a first-order lag. Thereby, the voltage command values vd * and vq * including the induced electromotive force generated by the current change of the synchronous motor 108 can be calculated. By applying the voltage command values vd * and vq * thus calculated to the synchronous motor 108, the response time until the motor current reaches the current command values id * and iq * is shortened, and the synchronous motor 108 is obtained. The response speed can be increased.

  FIG. 2 is a diagram illustrating the internal configuration of the voltage command calculator 109. The voltage command calculator 109 shown in FIG. 2 includes a response current calculator 109a and a voltage command calculator 109b.

上記、式（５），（６）においてＴｄ，Ｔｑは、それぞれ応答電流値ｉｄｓ，ｉｄｑの時定数、ｓはラプラス演算子（ｄ／ｄｔ）である。 The response current calculation unit 109a obtains response current values ids and idq in which the current command values id * and iq * output from the angular velocity controller 105 are expressed by a first-order lag according to the following equations (5) and (6).

In the above formulas (5) and (6), Td and Tq are time constants of response current values ids and idq, respectively, and s is a Laplace operator (d / dt).

Based on the current command values id *, iq *, the response current values ids, idq, and the rotational angular velocity ω of the synchronous motor 108, the voltage command calculation unit 109b calculates the voltage command value vd * by the following equations (7), (8). And the voltage command value vq * is calculated.

  In the voltage command calculator 109, the values of the resistance R, the inductance Ld, the inductance Lq, and the magnetic flux φ of the synchronous motor 108 are set in advance, so that the voltage command value vd * is obtained using the equations (7) and (8). , Vq * can be obtained.

  The coordinate converter 110 uses the voltage command values vd * and vq * output from the voltage command calculator 109 and the rotation angle Θs of the control shaft output from the rotation angle sensor 104 to convert a three-phase AC voltage command value. Output.

次に、行列式（１０）を用い、二軸座標上の電圧指令値ｖα*，ｖβ*を三軸座標上の電圧指令値ｖｕ*，ｖｖ*，ｖｗ*に変換する。

以上により三相交流電圧指令値ｖｕ*，ｖｖ*，ｖｗ*が算出される。 Hereinafter, a method for obtaining the three-phase AC voltage value command values vu *, vv *, and vw * in the coordinate converter 110 will be described.
First, voltage command values vd * and vq * on the rotating biaxial coordinates are converted into voltage command values vα * and vβ * on the biaxial coordinates using the following determinant (9).

Next, the determinant (10) is used to convert the voltage command values vα *, vβ * on the biaxial coordinates into the voltage command values vu *, vv *, vw * on the triaxial coordinates.

Thus, the three-phase AC voltage command values vu *, vv *, and vw * are calculated.

  The inverter 107 applies a three-phase AC voltage to the synchronous motor 108 based on the three-phase AC voltage command values vu *, vv *, vw * output from the coordinate converter 110. The inverter 107 is controlled by a PWM control method in which an average voltage applied to the synchronous motor 108 within a unit time is changed along a sine wave by turning on / off the internal switch.

  In the present embodiment, the voltage command values vd * and vq including the induced electromotive force generated by the current change of the synchronous motor 108 using the response current values ids and idq in which the current command values id * and iq * are expressed by first-order delay. Since * is calculated, the response of the synchronous motor 108 can be speeded up. As a result, the lift amount of the valve in the variable valve mechanism 101 can be changed at a high speed in accordance with the change in the output of the engine, and the fuel consumption can be improved.

Embodiment 2. FIG.
FIG. 3 is a diagram showing a valve control system according to another embodiment of the present invention. The valve variable mechanism driving device of the valve control system of FIG. 3 detects the rotation angle Θm of the synchronous motor 108 by the Hall sensor 111 which is a rotation angle detector. The Hall sensor 111 is installed on the stator of the synchronous motor 108. When the number of pole pairs P is 3, the Hall voltage is applied at the timing when each pole arranged on the rotor of the synchronous motor 108 at intervals of 60 degrees passes. To detect. Therefore, the rotation angle Θm of the synchronous motor 108 every 60 degrees between 0 degree and less than 360 degrees can be detected.

  The motor control device 200 calculates from the control shaft rotation angle command value Θs * input from the outside in accordance with the depression amount of the accelerator pedal of the automobile and the control angle calculated from the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111. A three-phase AC voltage is output using the rotation angle Θs of the shaft, and the synchronous motor 108 is driven and controlled. The rotation angle controller 203 outputs an angular velocity command ω * of the synchronous motor 108 based on the rotation angle command value Θm * of the synchronous motor 108 and the rotation angle Θm of the synchronous motor 108. The angular velocity converter 206 outputs the angular velocity ω of the synchronous motor 108 based on the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111.

Hereinafter, calculation of the angular speed ω of the synchronous motor 108 in the speed converter 206 will be described.
Since the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111 is a value every 60 degrees, the time differential value of the rotation angle Θm becomes a value in which sharp peaks are arranged every 60 degrees, and the angular velocity ω of the synchronous motor 108 Cannot be calculated accurately.
Therefore, a value obtained by filtering the value obtained by time differentiation of the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111 with a first-order lag filter is used as the angular velocity of the synchronous motor 108. As a result, an accurate angular velocity ω of the synchronous motor 108 can be obtained.

  Next, a method for calculating the angular velocity ω of the synchronous motor 108 without using a first-order lag filter will be described. As described above, the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111 is a value less than 360 degrees and every 60 degrees. Therefore, if the time interval for detecting the rotation angle Θm of the synchronous motor 108 based on the output of the Hall sensor 111 is longer than the time interval for one rotation of the synchronous motor 108, the rotation angle Θm of the synchronous motor 108 cannot be detected.

  For example, if the synchronous motor 108 rotates 400 degrees while detecting the rotation angle Θm of the synchronous motor 108 once based on the output of the Hall sensor 111, if the first detection value is 0 degree, the next detection The value is 60 degrees, the next detected value is 120 degrees, and the detection is a false detection.

  Therefore, the time interval for detecting the rotation angle Θm of the synchronous motor 108 based on the output of the Hall sensor 111 is set to be shorter than the minimum rotation period of the synchronous motor 108, and the angular velocity converter 206 detects the detected synchronous motor 108. The change amount of the rotation angle Θm is added a predetermined number of times and divided by the detection time interval. Thereby, the angular velocity ω of the synchronous motor 108 can be calculated. The number of additions of the change amount is an arbitrary number, but a more accurate rotational angular velocity of the synchronous motor 108 can be obtained by increasing the number of additions.

  Further, although time differentiation is not performed in the above example, differentiation is performed on the rotation angle Θm of the synchronous motor 108 detected by the Hall sensor 111 to obtain an angular velocity ω of the synchronous motor 108, and then a predetermined angular velocity ω is determined. The number of peaks in time can also be detected. That is, if the rotation angle of the synchronous motor 108 is detected at regular intervals, the rotation angular velocity of the synchronous motor 108 within the predetermined time can be calculated from the number of peaks observed.

Since the coordinate converter 210 performs a calculation based on the rotation angle Θm of the synchronous motor 108 output from the hall sensor 111, the three-phase voltage command values vv *, vu *, vw * are obtained from the voltage command values vd *, vq *. The coordinate conversion to can be performed more accurately than using the rotation angle Θs of the control shaft.
Further, when the three-phase voltage command values vv *, vu *, and vw * are obtained using Expression (9), the value of the cos function or the sin function is required. Since the output of the hall sensor 111 is a value every 60 degrees from 0 degree to less than 360 degrees, there are six types of cos functions or sin functions of 0 degree, 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees. The coordinate converter may be provided with a memory storing the value of. Even using such a low-precision Hall sensor 111, the three-phase voltage command values vv *, vu *, and vw * can be accurately obtained.

  In the present embodiment, the three-phase voltage command values vv *, vu *, and vw * can be calculated more accurately, so that the response speed of the synchronous motor 108 can be further increased. In addition, by using the Hall sensor 111 with low accuracy, the memory capacity necessary for the coordinate converter 210 can be reduced and the cost can be reduced.

Embodiment 3 FIG.
FIG. 4 is a diagram illustrating a valve control system according to another embodiment of the present invention. The valve variable mechanism driving device of the valve control system of FIG. 4 includes both a rotation angle sensor 104 that is a first rotation angle detector and a hall sensor 111 that is a second rotation angle detector.

Since the rotation angle controller 103 calculates the angular velocity command value ω * based on the rotation angle Θs of the control shaft output from the rotation angle sensor 104, the rotation angle controller 103 performs more accurate control than using the rotation angle Θm of the synchronous motor 108. The rotation angle of the shaft can be controlled.
Further, since the coordinate converter 210 performs a calculation based on the rotation angle Θm of the synchronous motor 108 output from the Hall sensor 111, the three-phase voltage command values vv *, vu *, The coordinate conversion to vw * can be performed more accurately than using the rotation angle Θs of the control shaft.

  As described above, in this embodiment, the angular velocity command value ω * and the three-phase voltage command values vv *, vu *, and vw * can be calculated more accurately. Speed can be increased.

Embodiment 4 FIG.
As shown in equations (3) and (4), the voltage of the synchronous motor 108 is the resistance drop voltage R × id * and R × iq *, and the induced electromotive force (Ld × d / dt) × id generated by the current change. * And (Lq × d / dt) × iq *, the induced electromotive force generated by the steady-state current −ωLqiq and ωLdid, and the sum of the induced voltage ωφ due to the rotor magnetic flux.
When the voltage vq of the q-axis component applied to the synchronous motor 108 is increased, the angular velocity ω of the synchronous motor 108 is increased. However, the output voltage vq of the inverter 107 has an upper limit, and the angular velocity ω when the maximum output voltage Vqmax of the q-axis component of the inverter 107 is applied to the synchronous motor 108 becomes the maximum angular velocity ωmax of the synchronous motor 108. Here, the maximum angular velocity ωmax can be expressed by the following equation (11) using the maximum output voltage Vqmax.
ωmax≈Vqmax / (φ + Ld × id) (11)

As shown by the above equation (11), when the maximum output voltage Vqmax is applied and the d-axis component current id is zero, the maximum angular velocity ωmax is a value obtained by dividing the maximum output voltage Vqmax by the rotor magnetic flux φ. . On the other hand, if the current id is negative, a magnetic flux represented by Ld × id is generated in a direction that cancels out the magnetic flux φ of the rotor, and the term of (φ + Ldid) decreases, so that the maximum angular velocity ωmax of the synchronous motor 108 is increased. Can be made.

  Thus, by generating magnetic flux in a direction that cancels the magnetic flux φ of the rotor, the maximum angular velocity ωmax of the synchronous motor 108 can be increased without increasing the maximum output voltage Vqmax. Thereby, the maximum rotational angular velocity of the control shaft of the variable valve mechanism 101 can be increased, and a higher control response speed can be obtained.

  The synchronous motor 108 includes a permanent magnet type synchronous motor using a permanent magnet as a rotor and a field winding type synchronous motor using an electromagnet with a winding as a rotor, but the field winding type synchronous motor is large. In order to obtain torque, it is required to increase the number of windings of the rotor or to increase the thickness of the winding. By increasing the radius and mass of the rotor due to this requirement, the inertia of the rotor increases. Response speed cannot be increased. On the other hand, the permanent magnet type synchronous motor does not require winding, and the volume and thickness of the permanent magnet are smaller and thinner than the field winding, so that the radius and weight of the rotor can be reduced. Can reduce the inertia. Therefore, the response speed of the motor can be increased by using a permanent magnet type synchronous motor that does not use a winding for the rotor.

  The synchronous motor 108 may be a field winding type synchronous motor, and an induction motor may be used instead of the synchronous motor 108. Further, the number of pole pairs of the synchronous motor 108 may be any number. The output of the hall sensor 111 may be an output every 90 degrees or every 45 degrees.

Further, in the rotation angle controller 103, proportional control is performed by multiplying the difference between the rotation angle command value Θs * of the control shaft and the rotation angle Θs of the control shaft by a proportional gain. Control using at least one of integral control that multiplies the integral gain, differential control that multiplies the differential time change value by the differential gain, and proportional control may be used.
Further, although the proportional-plus-integral control combining the proportional control and the integral control is performed in the angular velocity controller 105, the control method may be a control using at least one of proportional, integral, and differentiation.

The rotation angle sensor may be a resolver, an encoder, a hall sensor, or the like.
The hall sensor 111 may be a resolver or an encoder. By using a resolver or an encoder, the resolution of detection of the motor rotation angle is improved, and the control response speed and control accuracy in the control of the synchronous motor 108 can be improved. Thereby, the control response speed and control accuracy in the valve control of the variable valve mechanism 101 can be improved.

  Further, the gear ratio connecting the synchronous motor 108 and the control shaft of the variable valve mechanism 101 is set so that the rotational speed of the synchronous motor 108 with respect to the rotational speed of the control shaft is increased (for example, 1: 200). The rotation angle of the control shaft can be controlled with high resolution.

It is a figure showing the valve control system concerning Embodiment 1 of the present invention. It is a figure showing the internal structure of the voltage command calculating unit of this invention. It is a figure showing the valve | bulb control system which concerns on Embodiment 2 of this invention. It is a figure showing the valve control system concerning Embodiment 3 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Motor control apparatus 101 Valve variable mechanism 104 Rotation angle sensor 108 Synchronous motor 109 Voltage command calculator 109a Response current calculation part 109b Voltage command calculation part 111 Hall sensor

Claims (8)

A motor that rotationally drives the control shaft of the variable valve mechanism;
A variable valve mechanism driving device including a motor control device that controls the motor based on a rotation angle command value of the control shaft given from the outside,
The motor control device
A rotation angle controller that calculates an angular velocity command value to be given to the motor so that the rotation angle of the control shaft matches the rotation angle command value;
An angular velocity controller for calculating a current command value to be given to the motor so as to match the angular velocity of the motor with the angular velocity command value;
By inputting the current command value and the angular velocity of the motor, and calculating the resistance voltage of the motor, the induced electromotive force caused by the current change, the induced electromotive force caused by the steady current, and the induced voltage caused by the rotation of the motor A voltage command calculator that outputs a voltage command value of the motor;
The voltage command calculator is
A variable valve mechanism driving apparatus characterized in that a response current value representing a current command value of the motor by a first order lag is obtained, and an induced electromotive force generated by a change in the current of the motor is calculated using the response current value. A rotation angle detector for detecting the rotation angle of the control shaft;
An angular velocity converter that calculates an angular velocity of the motor from the detected rotation angle of the control shaft;
The rotation angle controller calculates an angular velocity command value of the motor based on the detected rotation angle of the control shaft,
The angular velocity controller calculates a current command value of the motor based on the calculated angular velocity;
2. The variable valve mechanism driving device according to claim 1, wherein the voltage command computing unit calculates a voltage command value of the motor using the calculated angular velocity. A rotation angle detector for detecting the rotation angle of the motor;
An angular velocity converter that calculates an angular velocity of the motor from the detected rotation angle of the motor;
The rotation angle controller outputs an angular velocity command value of the motor based on the rotation angle of the control shaft calculated from the detected rotation angle of the motor;
The angular velocity controller calculates a current command value of the motor based on the calculated angular velocity;
2. The variable valve mechanism driving device according to claim 1, wherein the voltage command calculator outputs a voltage command value of the motor using the calculated angular velocity. The angular velocity controller is for calculating a current command value on a rotating biaxial coordinate,
The voltage command calculator calculates a voltage command value on the rotating biaxial coordinates,
The motor control device
A coordinate converter that converts the voltage command value on the rotating biaxial coordinates into a three-phase AC voltage command value based on the rotation angle of the control shaft;
The variable valve mechanism driving device according to claim 1, further comprising an inverter that applies a voltage to the motor based on a three-phase AC voltage command value output from the coordinate converter. A first rotation angle detector for detecting the rotation angle of the control shaft;
A second rotation angle detector for detecting the rotation angle of the motor;
An angular velocity converter that calculates an angular velocity of the motor from the detected rotation angle of the control shaft;
A coordinate converter for converting a voltage command value on a rotating biaxial coordinate into a three-phase AC voltage command value based on the detected rotation angle of the motor;
An inverter for applying a voltage to the motor based on a three-phase AC voltage command value output from the coordinate converter;
The rotation angle controller outputs an angular velocity command value of the motor based on the detected rotation angle of the control shaft,
The angular velocity controller calculates a current command value on the rotation biaxial coordinates of the motor based on the calculated angular velocity,
2. The variable valve mechanism driving device according to claim 1, wherein the voltage command calculator outputs a voltage command value on a rotation biaxial coordinate of the motor using the calculated angular velocity. When the angular velocity of the motor is equal to or greater than the value obtained by dividing the maximum output voltage of the inverter by the magnetic flux of the rotor of the motor, the d-axis component on the rotating biaxial coordinates of the current command value is negative. The valve variable mechanism drive device according to claim 4 or 5. A motor that rotationally drives the control shaft of the variable valve mechanism;
A variable valve mechanism drive device comprising: a motor control device that controls the motor based on a rotation angle command value of the control shaft given from the outside;
The variable valve mechanism driving apparatus, wherein the motor includes a rotor made of a permanent magnet.   8. A variable valve mechanism having a control shaft connected to the motor and changing a lift amount of the valve by the control shaft driven to rotate by the motor. The valve control system described in.

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