JP4723846B2 - Motor control device - Google Patents

Description

The present invention is, DVD, CD, relates makes the chromophore at the distal end over motor controller to drive rotating the disk recording medium such as HDD.

  2. Description of the Related Art In recent years, information storage devices have used disk storage devices that rotate and drive a disk as a recording medium to record / read signals. The disk is fixed to a spindle motor and rotated at high speed. For the purpose of miniaturization, a permanent magnet motor is generally used as a spindle motor.

  A conventional spindle motor control device will be described with reference to FIG. In the spindle motor control device 85, the output terminals of the hall elements Hu, Hv, and Hw that are attached to the spindle motor and connected to the power source via the resistor 70 and connected to the ground via the resistor 71 are connected to the control IC 84. Connected to the input terminal. The output signals of the hall elements Hu, Hv, and Hw are amplified by the amplifier 72 and then differentially amplified by the amplifier 73. At this time, the gain is determined by a signal obtained by synthesizing the differential amplification result of the current command SI by the differential amplifier 75 and the reference potential 74 and the output of the current detection resistor 82 by the differential amplifier 77 and the differential amplification result of the reference potential 76. Is done.

  These signals are passed through an inverting circuit 86 whose non-inversion / inversion is controlled by a brake command SB, and then compared with the outputs of the triangular wave generator 78 by respective comparators 79 and converted into PWM signals. The three-phase PWM signals are supplied as FET.Fu, Fv, FW via the upper gate drive circuit 80, and as FET.Fx, Fy, Fz via the lower gate drive circuit 81. Therefore, the Hall elements waveform is amplified to form a pseudo sine wave waveform to the motor windings Lu, Lv, and Lw, and the three-phase PWM that is duty adjusted by the current command SI is supplied. The motor is driven to rotate.

FIG. 12 shows a timing chart. For the output signals of the hall elements Hu, Hv, Hw, sinusoidal PWM voltages Vu, Vv, Vw (indicated by broken lines in the figure) are supplied to the motor windings Lu, Lv, Lw. Is done. The currents Iu, Iv, Iw flowing through the motor windings Lu, Lv, Lw are delayed with respect to the voltage. When the brake command SB is input, the inverted sinusoidal PWM voltage is supplied to the motor to generate a braking force.
In addition, the thing similar to the above structures is disclosed by patent documents 1-3 etc., for example.
No. 01/039358 JP 2004-242417 A JP 2003-339143 A

However, the spindle motor control device having the configuration described above is required to be downsized and cost-reduced, but there is a problem that the hole element attached to the motor is an obstacle. .
The present invention has been made in view of the above circumstances, and its object is a rotational position sensor disposed permanent magnet motor in terms of the non-essential, winding the sinusoidal current of the motor by a three-phase PWM signal it is to provide a makes the chromophore at the distal end over motor controller can be energized lines.

In order to achieve the above object, the motor control device of the present invention provides:
A permanent magnet motor comprising a rotor having a permanent magnet and a stator provided with a three-phase winding;
Current detecting means for detecting a current of the three-phase winding;
Current conversion means for calculating a magnetic flux axial direction component current (d-axis current) of the permanent magnet motor and a torque axial direction component current (q-axis current) orthogonal thereto from the current of the three-phase winding;
Power calculating means for calculating the power of the permanent magnet motor;
D-axis current command forming means for calculating a d-axis current command based on the power;
Q-axis current command forming means for calculating a q-axis current command based on a current command given from outside;
Voltage calculating means for calculating a d-axis voltage and a q-axis voltage based on the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current;
Induced voltage calculation means for calculating a d-axis induced voltage based on the d-axis current, the q-axis current, and the d-axis voltage;
Angular velocity calculation means for determining the angular velocity of the rotor based on the d-axis induced voltage;
Position estimating means for estimating the rotational position of the rotor based on the angular velocity;
PWM signal forming means for forming a three-phase PWM signal from the d-axis voltage, the q-axis voltage, and the rotational position;
Energization means for energizing the windings of the permanent magnet motor based on the three-phase PWM signal ;
When braking the rotation of the permanent magnet motor, regenerative braking is performed after short-circuit braking is performed for a predetermined time or a predetermined number of revolutions or more, and then a negative current command SI given from the outside at a predetermined number of revolutions or less is supported. And a brake control means for controlling to perform positioning by energizing the three-phase winding .

If comprised in this way, a current conversion means will calculate the d-axis current which is a magnetic flux axial direction component, and the q-axis current which is a torque axial direction component from the three-phase winding current of a permanent magnet motor, and d-axis current command The forming means calculates a d-axis current command based on the power of the permanent magnet motor, and the q-axis current command forming means calculates a q-axis current command based on a current command given from the outside. The voltage calculation means calculates the d-axis and q-axis voltages based on the d-axis and q-axis current commands and the d-axis and q-axis currents.
When the induced voltage calculation means calculates the d-axis induced voltage based on the d-axis and q-axis currents and the d-axis voltage, the angular speed calculation means determines the angular speed of the rotor based on the d-axis induced voltage, and the position The estimating means estimates the rotational position of the rotor from the angular velocity. Further, the PWM signal forming means forms a three-phase PWM signal from the d-axis and q-axis voltages and the rotational position, and the energizing means energizes the windings of the permanent magnet motor based on the three-phase PWM signal. Further, when braking the rotation of the permanent magnet motor, the brake control means performs a regenerative brake after performing a short-circuit brake for a predetermined time or at a predetermined rotation speed or higher, and then applies a negative brake applied from the outside at a predetermined rotation speed or lower. In response to the current command SI, the three-phase winding is energized to perform positioning.

According to the present invention, it is possible to energize the windings of a permanent magnet motor with an arbitrary waveform using a PWM signal without using a rotational position sensor, so that the motor control device can be configured in a small size and at low cost. it can. In addition, a stable stop operation can be realized even with a sensorless system.

(First embodiment)
The configuration of the first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a functional block diagram showing the configuration of the spindle motor control device 1. In FIG. 1, among three-phase windings Lu, Lv, Lw of a permanent magnet motor constituted by, for example, a brushless DC motor, shunt resistors (current detection means) 11, 12 are connected in series to the windings Lu, Lv. The both ends of the shunt resistors 11 and 12 are connected to current detection circuits (current detection means) 13 and 14, respectively.

  FIG. 2 shows the configuration of the current detection circuits 13 and 14. The current detection circuits 13 and 14 are composed of operational amplifiers 60 and 61 and a resistor and reference voltage generator 62. The peripheral resistors R1, R2, R3, and R4 of the operational amplifier 60 have the same resistance value, and the difference voltage between the input voltages x and y is output with reference to the reference voltage Vr. The operational amplifier 61 is an inverting amplifier, and amplifies the output signal of the operational amplifier 60 with an amplification factor Rb / Ra with reference to the voltage Vr.

  When the AD conversion circuit 15 performs analog / digital conversion on the output signals of the current detection circuits 13 and 14, the conversion result of the output signal from the current detection circuit 13 is Iu, the conversion result of the output signal from the current detection circuit 14 is Iv, -Iu-Iv is output as Iw. The AD conversion circuit 15 also AD converts the power supply voltage supplied to the energizing means (inverter) 83 including six FETs Fu to Fw and Fx to Fz connected in a three-phase bridge. The signal is output as Vdc.

  The current converter 16 receives the currents Iu, Iv, Iw and the angle Θ, and calculates a magnetic flux axis direction component current Id and a torque axis direction component current Iq orthogonal to the magnetic flux axis direction. The d-axis current Id is compared with a d-axis current command Idr by a comparator (voltage calculation means) 17 and supplied to a PI controller (voltage calculation means) 18. Similarly, the q-axis current Iq is compared with the q-axis current command Iqr by the comparator (voltage calculation means) 19 and supplied to the PI controller (voltage calculation means) 20. The d-axis current command Idr is generated and output by the d-axis current command forming unit 27 in response to the power Wm given by the power calculating unit 26. The q-axis current command Iqr is generated and output by the q-axis current command forming means (amplitude calculating means) 25. Then, the PI controllers 18 and 20 perform proportional / integral processing on the signals output from the comparators 17 and 19 to form the d-axis voltage Vd and the q-axis voltage Vq.

  The PWM signal forming means 21 forms a PWM waveform Vu, Vv, Vw of a three-phase voltage from the voltages Vd, Vq and the angle Θ by a so-called space vector method, but the two-phase modulation signal pattern and the three-phase modulation signal are generated by the signal SM. The pattern can be switched. The gate drive circuits 80 and 81 amplify the PWM waveforms Vu, Vv and Vw of the three-phase voltage and output them to the respective gate terminals of the energizing means 83. As for each phase output terminal of the energizing means 83 having a three-phase configuration, the U and V phases are directly connected to the motor windings Lu, Lv and Lw via the shunt resistors 11 and 12, respectively.

  The induced voltage calculation means 22 outputs a signal Ed generated by being supplied with the currents Id and Iq and the voltages Vd and Vq to the angular velocity calculation means 23. Then, the angular velocity calculation means 23 calculates the angular velocity ω from the signal Ed, and the angle calculation means (position estimation means) 24 generates and outputs the angle Θ based on the angular velocity ω. At the same time, for example, a rotation signal FG as motor speed information is output to a host CPU (not shown).

  The spindle motor control device 1 is provided with a start / stop signal SO, a current command (torque command) SI, and a low angular velocity command SF, for example, by a host CPU. The start / stop signal SO is input to a start control means (low-speed rotation control means) 28 for performing sequence control at the time of starting the motor and a brake control means 29 for performing sequence control at the time of motor braking, and the current command SI is converted to an AD conversion circuit 30. The low angular velocity command SF is input to the start control unit 28 via the AD conversion circuit 31. That is, the spindle motor control device 1 is configured to perform sensorless vector control.

Next, the operation of the present embodiment will be described with reference to FIGS. The signal z output from the current detection circuits 13 and 14 that has received the voltage across the shunt resistors 11 and 12 is expressed by equation (0).
z = (Rb / Ra) (y−x) + Vr (0)
Accordingly, the voltages across the shunt resistors 11 and 12 are amplified with reference to the voltage Vr and supplied to the AD conversion circuit 15. The AD conversion circuit 15 outputs the conversion result of the current detection circuit 13 side output as Iu, the conversion result of the current detection circuit 14 side output as Iv, and −Iu−Iv as Iw. The AD conversion circuit 15 stores the AD conversion result in the energized off state (reference voltage Vr), and calculates Iu and Iv as the difference from the AD conversion result.

比較器１７,１９及びＰＩ制御器１８,２０においては、（３）式によりｄ軸電圧Ｖｄ及びｑ軸電圧Ｖｑが形成される。

ここで、Ｋｐは比例ゲイン、ＫＩは積分ゲインである。 The current conversion means 16 calculates the magnetic flux axis direction component current Id and the torque axis direction component current Iq by the equations (1) and (2).

In the comparators 17 and 19 and the PI controllers 18 and 20, the d-axis voltage Vd and the q-axis voltage Vq are formed by the equation (3).

Here, Kp is a proportional gain, and KI is an integral gain.

ＰＷＭ信号形成手段２１では信号ＳＭによって２相変調出力パターンと３相変調出力パターンとが切り換えられるが、まず、２相変調が選択されている場合について説明する。ＰＷＭ信号形成手段２１は、電圧Ｖα,Ｖβを受けて図３に示すような６個のセクタに分類し夫々次の演算により信号波Ｖｕ,Ｖｖ,Ｖｗを形成する。ここで、Ｄ１,Ｄ２はオンオフ比率（デュ−ティ）を表す変数、Ｆはデュ−ティに換算するための定数である。 The PWM signal forming means 21 calculates Vα and Vβ by the equation (4).

The PWM signal forming means 21 switches between the two-phase modulation output pattern and the three-phase modulation output pattern according to the signal SM. First, the case where the two-phase modulation is selected will be described. The PWM signal forming means 21 receives the voltages Vα and Vβ, classifies them into six sectors as shown in FIG. 3, and forms signal waves Vu, Vv, and Vw by the following calculations, respectively. Here, D1 and D2 are variables representing an on / off ratio (duty), and F is a constant for converting to a duty.

(1) When the voltage vector V belongs to the sector 1 The voltage vector V (Vα, Vβ) is separated into a component of the voltage vector V1 (1, 0, 0) and a component of the voltage vector V2 (1, 1, 0). Then, the variables D1 and D2 are calculated, and the signal waves Vu and Vv are determined based on these. Since the sector 1 is in the non-switching period of the W phase, the signal wave Vw becomes zero. The PWM signal forming means 21 calculates using the following equation (5).

(2) When the voltage vector V belongs to the sector 2 The voltage vector V is separated into the components of the voltage vectors V2 and V3 to obtain the variables D1 and D2, and the signal waves Vu and Vv are determined based on this. The signal wave Vw becomes zero. The calculation is performed by the following equation (6).

(3) When the voltage vector V belongs to the sector 3 The voltage vector V is separated into the components of the voltage vectors V3 and V4 to obtain the variables D1 and D2, and the signal waves Vv and Vw are determined based on this. The signal wave Vu becomes zero. The calculation is performed by the following equation (7).

(4) When the voltage vector V belongs to the sector 4 The voltage vector V is separated into the components of the voltage vectors V4 and V5 to obtain the variables D1 and D2, and based on this, the signal waves Vv and Vw are determined. The signal wave Vu becomes zero. The calculation is performed according to the following equation (8).

(5) When the voltage vector V belongs to the sector 5 The voltage vector V is separated into the components of the voltage vectors V5 and V6 to obtain the variables D1 and D2, and the signal waves Vw and Vu are determined based on these. The signal wave Vv becomes zero. The calculation is performed by the following equation (9).

(6) When the voltage vector V belongs to the sector 6 The voltage vector V is separated into the components of the voltage vectors V6 and V1, variables D1 and D2 are obtained, and the signal waves Vw and Vu are determined based on these. The signal wave Vv becomes zero. The calculation is performed by the following equation (10).

  The voltage signals Vu, Vv, Vw are converted into PWM signals, and the signals shown in FIG. 4 are output to the gate drive circuits 80, 81. As shown in FIG. 4 showing the waveforms between the U phase, the V phase, and the UV, these are signals with 120 degrees of non-switching periods for each phase, the switching loss is 2 arm, and the circuit loss is relatively small. However, since the switching period and the non-switching period are mixed, the sine wave accuracy is relatively poor.

Next, a case where three-phase modulation is selected by the signal SM will be described. Signal waves Vu, Vv, Vw are formed by the following calculation.
(1) When the voltage vector V belongs to the sector 1 The voltage vector V is separated into the components of the voltage vectors V1 and V2 to obtain the variables D1 and D2, and further the variable D0 corresponding to the zero vector is obtained. The signal waves Vu, Vv, Vw are determined. D0 corresponding to the generation time of the zero vector is divided into two, and the voltage vectors in the PWM period are, for example, V0 (0, 0, 0), V1 (1, 0, 0), V2 (1, 1, 0), V7. It is switched in the order of (1, 1, 1). The calculation is performed according to the following equation (11).

(2) When the voltage vector V belongs to the sector 2 The voltage vector V is separated into the components of the voltage vectors V2 and V3 to obtain the variables D1, D2, and D0, and the signal waves Vu, Vv, and Vw are determined based on these. To do. The calculation is performed by the following equation (12).

(3) When the voltage vector V belongs to the sector 3 The voltage vector V is separated into the components of the voltage vectors V3 and V4 to obtain the variables D1, D2 and D0, and the signal waves Vu, Vv and Vw are determined based on these. To do. The calculation is performed by the following equation (13).

(4) When the voltage vector V belongs to the sector 4 The voltage vector V is separated into the components of the voltage vectors V4 and V5 to obtain the variables D1, D2 and D0, and the signal waves Vu, Vv and Vw are determined based on these. To do. The calculation is performed according to the following equation (14).

(5) When the voltage vector V belongs to the sector 5 The voltage vector V is separated into the components of the voltage vectors V5 and V6 to obtain the variables D1, D2, and D0, and the signal waves Vu, Vv, and Vw are determined based on these. To do. The calculation is performed according to the following equation (15).

(6) When the voltage vector V belongs to the sector 6 The voltage vector V is separated into the components of the voltage vectors V6 and V1, variables D1, D2 and D0 are obtained, and the signal waves Vu, Vv and Vw are determined based on these. To do. The calculation is performed by the following equation (16).

The voltage signals Vu, Vv, Vw are converted into PWM signals, and the signals shown in FIG. 5 are output to the gate drive circuits 80, 81. As can be seen from FIG. 5 showing waveforms between the U phase, the V phase, and the UV, there is no non-switching period, so the circuit loss is relatively high, but the sine wave accuracy is high.
The gate drive circuits 80, 81 amplify the PWM waveforms Vu, Vv, Vw of the three-phase voltage, supply on / off signals to the gate terminals of the energizing means 83, and sine with respect to the motor windings Lu, Lv, Lw. A wave PWM voltage is generated. Accordingly, a sine wave current flows through the motor windings Lu, Lv, and Lw, and the motor is driven to rotate. At the same time, the current follows the d-axis current command Idr and the q-axis current command Iqr.

Next, an operation for estimating the rotation angle of the motor without using the rotational position sensor will be described. The induced voltage computing means 22 computes the d-axis induced voltage according to equation (17).
Ed = Vd−R · Id + ωL · Iq (17)
Here, R and L are motor constants. If the dq axis on the circuit matches the dq axis of the motor, the d axis induced voltage Ed should be zero, and if the voltage Ed is not zero, the axis does not match. ing. When the voltage Ed is positive, the dq axis on the circuit is advanced with respect to the dq axis of the motor, and when the voltage Ed is negative, the dq axis on the circuit is delayed with respect to the dq axis of the motor. The angular velocity calculation means 23 calculates the angular velocity ω by the equation (18).
ω = ωo−K · Ed (18)
Here, K is a gain constant. The angle calculation means 24 obtains the angle Θ by integrating the angular velocity ω. By repeating these processes, the angular velocity ω and the angle Θ are calculated so that the dq axis on the circuit matches the dq axis of the motor.

そして、図６に示す関係で電流指令ＳＩからｑ軸電流指令Ｉqrを形成する。図６は、ＳＩが正の場合を示しているが、負の場合も同様である。即ち、（２０）式となる。
Ｖout＜０.９５・Ｖdc Ｉqr＝ＳＩ
０.９５・Ｖdc≦Ｖout＜Ｖdc Ｉqr＝２０・ＳＩ・（Ｖdc−Ｖout）／Ｖdc
Ｖdc≦Ｖout Ｉqr＝０
・・・（２０）
これにより、電源電圧Ｖdcと出力電圧Ｖoutを常に監視して、オーバーフロー（Ｖdc≦Ｖout）しないようにｑ軸電流指令Ｉqrを制限するので、オーバーフローによる電圧Ｖoutの歪を原因とする電流波形の乱れは発生しない。この動作により、通常は電流指令ＳＩに依存してモータのｑ軸電流が制御される。 Next, the operation of forming a q-axis current command will be described. The current command SI is input to the q-axis current command forming unit 25 via the AD conversion circuit 30. The q-axis current command forming means 25 basically sets the q-axis current command Iqr according to the current command SI and outputs a positive / negative value, but limits the q-axis current command Iqr under the output voltage overflow condition. . First, the output voltage Vout (the amplitude of the output line voltage) is calculated by the equation (19).

Then, the q-axis current command Iqr is formed from the current command SI in the relationship shown in FIG. FIG. 6 shows the case where SI is positive, but the same is true for negative cases. That is, equation (20) is obtained.
Vout <0.95 ・ Vdc Iqr = SI
0.95 · Vdc ≦ Vout <Vdc Iqr = 20 · SI · (Vdc−Vout) / Vdc
Vdc ≦ Vout Iqr = 0
... (20)
As a result, the power supply voltage Vdc and the output voltage Vout are constantly monitored, and the q-axis current command Iqr is limited so as not to overflow (Vdc ≦ Vout). Therefore, the disturbance of the current waveform caused by the distortion of the voltage Vout due to overflow is prevented. Does not occur. By this operation, the q-axis current of the motor is normally controlled depending on the current command SI.

Next, the operation for forming the d-axis current command Idr will be described. In the power calculation means 26, the power Wm is calculated by the equation (21).
Wm = 3 · (Vd · Id + Vq · Iq) / 2 (21)
This electric power Wm is usually a positive value, but may take a negative value when the current command SI is negative and the motor is braked. The d-axis current command forming means 27 receives the electric power Wm and obtains the d-axis current command Idr by the equation (22).
Idr = Idr + Kw · Wm (22)
However, Idr ≦ 0
Therefore, when the power Wm is positive, the d-axis current command Idr maintains zero, and when the power Wm becomes negative, the d-axis current command Idr changes in the negative direction. Thereafter, when the power Wm returns to positive, the d-axis current command Idr also changes in the zero direction. Although the d-axis current is controlled by this operation, the d-axis current is a current that does not contribute to torque, and has an effect of generating heat at the winding resistance. If the d-axis current is increased when the electric power becomes negative, that is, when the voltage generated when the motor is braked is regenerated to the power supply side via the energizing means 83, The electric power is consumed by the heat generated in the winding, and the regenerative state can be avoided.

Next, the operation of the start control means 28 will be described with reference to the flowchart of FIG. The start control means 28 starts processing when the start / stop signal SO changes from stop to start, and works on each means described so far to control each variable.
(1) Positioning stage Initially, the rotor is positioned. In this positioning stage, the d-axis current command forming unit 27 is actuated to increase the current command Idr from zero to the current command SI, and the output ω of the angular velocity calculating unit 23 is set to zero and the output Θ of the angle calculating unit 24 is initially set to zero. Turn into. Iqr by the q-axis current command forming means 25 is initialized to zero. As a result, a predetermined energization is performed on the motor, and the rotor stops at a predetermined position. The energization at this time is set to three-phase modulation by the signal SM. This positioning stage is completed in a predetermined time, and the process proceeds to the next forced rotation stage.

(2) Forced rotation stage In the next forced rotation stage, by increasing the output ω of the angular velocity calculating means 23, the output Θ of the angle calculating means 24 also changes and the motor starts rotating. At this time, the increase in the angular velocity ω is performed by, for example, equation (23). Ky is a constant.
ω = ω + Ky · SI (23)
That is, the control is performed so that the acceleration is slow when the current command SI is small and the acceleration is rapid when the current command SI is large. The angular velocity ω is limited by the low angular velocity command SF and cannot be larger than SF. Therefore, when the low angular velocity command SF is less than the predetermined value ωs, the forced rotation is continued at the angular velocity of SF. In the range of low angular velocity where the induced voltage generated in the motor is small, the motor rotates in accordance with the low angular velocity command SF.

The case where the value of the low angular velocity command SF is equal to or greater than the predetermined value ωs will be described continuously. The angular velocity ωs is an angular velocity at which an induced voltage is sufficiently generated in the motor, and the induced voltage calculation means 22 can calculate the d-axis induced voltage Ed. When the angular velocity ω reaches the predetermined value ωs, the operation proceeds to the next switching stage.
(3) Switching stage In the switching stage, the d-axis current command Idr is changed from the current command SI to zero, and the q-axis current command Iqr is changed from zero to the current command SI at the angular velocity ωs (Equation (24)). At the same time, the output ω of the angular velocity calculation means 23 is set to zero, and the change in the output Θ of the angle calculation means 24 is stopped.
Idr = SI · cos (ωs · t)
Iqr = SI · sin (ωs · t) (24)
In this switching stage, the d-axis induced voltage Ed of the induced voltage calculation means 22 is further monitored. The d-axis induced voltage Ed changes from plus to minus due to the change in current. When the d-axis induced voltage Ed becomes zero, the calculation result of the angular velocity calculation means 23 is adopted to obtain the angular velocity ω. Thereafter, the angular velocity ω enters a closed loop state that increases in accordance with the d-axis induced voltage Ed, and shifts to the next steady stage.

(4) Steady stage In the steady stage, the d-axis current command Idr is zero, and the q-axis current command Iqr is in accordance with the current command SI. At this time, when the rotational speed of the motor exceeds a predetermined rotational speed, the signal SM is set to the two-phase modulation side. As described above, it is possible to start a sine wave current following the current command while using the sensorless method. This state continues until the start / stop signal SO changes to stop.

  Next, the brake control means 29 will be described with reference to the flowchart of FIG. The brake control means 29 starts processing when the start / stop signal SO changes from start to stop, and works on each means to control each variable. When braking is required, for example, the start / stop signal SO is stopped and the negative current command SI is input to the spindle motor control device 1 from the host CPU.

(1) Short-circuit brake stage In the short-circuit brake stage, the signal SM is set to the two-phase modulation side, and at the same time, the PI controllers 18 and 20 are operated to set the voltages Vd and Vq to zero. As a result, the output of the PWM signal forming means 21 becomes “low” for the three phases, and the lower FETs Fx, Fy, Fz of the energizing means 83 are turned on. Thus, the windings Lu, Lv, Lw are short-circuited via the lower FETs Fx, Fy, Fz, and a braking force is generated. This short-circuit braking stage is continued when the rotational speed is equal to or higher than a predetermined number of revolutions or within a predetermined time, and when the condition is not met, the next regenerative braking stage is started.

(2) Regenerative braking stage In the regenerative braking stage, the negative q-axis current command Iqr is formed from the negative current command SI via the q-axis current command forming means 25, and the q-axis current of the motor is controlled by the current control loop. The At the same time, the power is calculated by the power calculation means 26, and in the case of negative, the d-axis current command forming means 27 forms a negative d-axis current command Idr. As described above, the braking operation controlled so that the electric power does not become negative is performed. Further, the braking force depends on the current command SI. The signal SM is switched between two-phase modulation and three-phase modulation according to the rotational speed. Although the motor is decelerated in the regenerative braking stage, there is a limit to the estimation of the motor rotation angle by detecting the induced voltage at low speed rotation. That is, when the rotational speed is less than or equal to the predetermined rotational speed ωs, the regenerative braking stage cannot be continued, and the process proceeds to the next positioning stage.

(3) Positioning Stage In the positioning stage, the output ω of the angular computing means 24 is fixed by setting the output ω of the angular velocity computing means 23 to zero. At the same time, the d-axis current command forming means 27 is operated to increase the current command Idr from zero to the absolute value of the current command SI, and Iqr by the q-axis current command forming means 25 is set to zero. Then, positioning torque is generated and the motor stops. This positioning step ends after continuing for a predetermined time.

As described above, according to the present embodiment, the current conversion means 16 is the d-axis current and the torque axis direction component that are the magnetic flux axis direction components from the current flowing through the three-phase windings Lu, Lv, and Lw of the permanent magnet motor. calculates a q-axis current, d-axis current command forming means 2 7 calculates the d-axis current command Idr based on the permanent magnet motor power Wm, the q-axis current command forming means 25, a current supplied from the outside A q- axis current command Iqr is calculated based on the command SI. The PI controllers 18 and 20 calculate the d-axis and q-axis voltages Vd and Vq based on the d-axis and q-axis current commands Idr and Iqr and the d-axis and q-axis currents Id and Iq.

Then, when the induced voltage calculating means 22 calculates the d-axis induced voltage Ed based on the d-axis and q-axis currents Id and Iq and the d-axis voltage Vd, the angular velocity calculating means 23 is based on the d-axis induced voltage Ed. The angular velocity ω of the rotor is determined, and the angle calculator 24 estimates the rotational position Θ of the rotor from the angular velocity. Further, the PWM signal forming means 21 forms three-phase PWM signals Vu, Vv, Vw from the d-axis and q-axis voltages Vd and Vq and the rotational position Θ, and the energizing means 83 is a three-phase PWM signal Vu, Vv. , Vw is applied to the windings Lu, Lv, Lw of the permanent magnet motor.
Accordingly, since the sine wave energization can be executed on the permanent magnet motor by the sensorless method, the spindle motor can be driven at a low cost and with high efficiency. In addition, the motor current is separated into the d / q axes by vector control, and the d-axis current Id that does not contribute to torque generation is controlled to zero during acceleration, maximizing acceleration capacity compared to voltage control. it can.

  Further, when the start control means 28 controls the energization means 83 to position the motor, the start control means 28 starts the motor start by forced commutation, and the energization based on the three-phase PWM signals Vu, Vv, Vw from the forced commutation. Since the start control is performed by switching to, the sensor can be stably started even in the sensorless system. Since the acceleration during forced rotation is controlled as a function of the current command SI, starting corresponding to a wide range of current commands is possible. Further, when the start control means 28 receives a low speed command SF from the outside, the start control means 28 performs the low speed rotation by controlling the angular speed ω by forced commutation. Therefore, even in the sensorless vector control system, the rotation in the low angular speed region is performed. Thus, a plurality of disc recording media such as DVD, CD, and HDD can be rotationally driven.

  Further, the brake control means 29 performs a short-circuit brake for a predetermined time or at a predetermined rotation speed or higher when braking the rotation of the permanent magnet motor, and then performs winding corresponding to the negative current command SI given from the outside. Therefore, stable stop operation can be realized even with a sensorless system. The d-axis current command forming means 27 outputs the d-axis current command Idr to control the motor power when the brake is applied to the motor. That is, in the conventional configuration, the power supply voltage may increase due to the regenerative power generated during braking, and the control IC may be destroyed. However, according to the present invention, an increase in the power supply voltage due to the regenerative power can be suppressed. .

  Further, the PWM signal forming means 21 can select an output waveform corresponding to two-phase modulation and three-phase modulation, selects three-phase modulation in the low-speed rotation region of the permanent magnet motor, and performs two-phase modulation in the high-speed rotation region. Therefore, three-phase modulation is performed with emphasis on waveform accuracy in the low angular velocity region, and two-phase modulation is performed in the high angular velocity region, thereby reducing switching loss and suppressing heat generation. In addition, the q-axis current command forming means 25 calculates the output voltage amplitude Vout and limits the q-axis current command Iqr in accordance with the comparison result with the power supply voltage Vdc. Vibration due to current distortion can be suppressed.

(Second embodiment)
FIG. 9 shows a second embodiment of the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only different parts will be described below. In the spindle motor control device 40 of the second embodiment, the portion surrounded by the broken line in FIG. 9 in the spindle motor control device 1 is configured using an arithmetic unit such as a microcomputer 41, and vector control calculation is performed. It is configured to execute at a PWM cycle or an integer multiple thereof.

そして、角度演算手段２４はハード処理化されており、角度Θを出力している。同じくハ−ド処理化されているＰＷＭ信号形成手段５１は、２相変調／３相変調の３相波形をＲＯＭテ−ブルで保有しており、（Θ＋Ｖphs）をアドレスとして読み出す。読み出した３相デ−タに電圧振幅Ｖampを乗算した後、ＰＷＭ信号に変換して出力する。 (Third embodiment)
FIG. 10 shows a third embodiment of the present invention. The spindle motor control device 42 according to the third embodiment is configured by a microcomputer 43 or the like in a portion surrounded by a broken line in FIG. The part corresponding to the PWM signal forming means 21 in the first embodiment is replaced with a PWM signal forming means 51 and a voltage converting means 52.
The voltage calculation means 52 of the microcomputer 43 receives the voltages Vd and Vq, and outputs the voltage amplitude Vamp and phase Vphs according to equation (25).

The angle calculation means 24 is hardware-processed and outputs an angle Θ. Similarly, the hard-processed PWM signal forming means 51 holds a three-phase waveform of two-phase modulation / three-phase modulation in a ROM table, and reads (Θ + Vphs) as an address. After the read three-phase data is multiplied by the voltage amplitude Vamp, it is converted into a PWM signal and output.

  The angle calculation means 24 and the PWM signal forming means 51 execute calculation processing at a PWM cycle or a cycle that is an integer multiple thereof, and the software processing in the microcomputer 43 is executed at a longer cycle. According to the third embodiment configured as described above, a microcomputer with low capability can be used, and a low-cost spindle motor control device 42 can be realized.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications are possible.
Although shunt resistors are arranged only in two phases of the three-phase windings, it is desirable to arrange shunt resistors in all three-phase windings in order to achieve a three-phase balance.
It is not always necessary to switch between two-phase modulation and three-phase modulation according to the rotation speed, and only three-phase modulation may be performed over all rotation speeds.
The sequence for starting the motor is not limited to that shown in FIG. For example, the switching step (3) may be omitted.

Further, in the (2) forced rotation stage of the start sequence, the acceleration rate does not necessarily have to be changed according to the q-axis current command Iqr, and the acceleration rate may be set constant.
The low speed rotation control means may be provided when it is necessary to perform low speed rotation according to individual design.
The process of limiting the q-axis current command Iqr according to the comparison result between the output voltage amplitude Vout and the power supply voltage Vdc may be performed as necessary.
Moreover, the sequence in the case of stopping by applying a brake to the rotating motor is not limited to that shown in FIG. For example, the short-circuit brake stage (1) or the regenerative brake stage (2) may be omitted.

1 is a functional block diagram illustrating a configuration of a spindle motor control device according to a first embodiment of the present invention. Diagram showing the configuration of the current detection circuit Voltage vector vector illustration Waveform diagram when using two-phase modulation Waveform diagram when using three-phase modulation The figure which shows the relationship between output voltage Vout and q-axis current command Iqr The flowchart which shows the starting sequence of the motor by the starting control means The flowchart which shows the braking sequence of the motor by a brake control means FIG. 1 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. 1 equivalent diagram showing the prior art Diagram showing position sensor signal, output current, and output voltage waveform

Explanation of symbols

In the drawing, 1 is a spindle motor control device, Lu, Lv and Lw are windings, 11 and 12 are shunt resistors (current detection means), 13 and 14 are current detection circuits (current detection means), 16 is current conversion means, Reference numeral 17 denotes a comparator (voltage calculation means), 18 denotes a PI controller (voltage calculation means), 19 denotes a comparator (voltage calculation means), 20 denotes a PI controller (voltage calculation means), 21 denotes a PWM signal forming means, 22 Is an induced voltage calculating means, 23 is an angular velocity calculating means, 24 is an angle calculating means (position estimating means), 25 is a q-axis current command forming means (amplitude calculating means), 26 is a power calculating means, and 27 is a d-axis current command forming. Means, 40 spindle motor control device, 41 is a microcomputer, 42 spindle motor control device, 43 is a microcomputer, 51 is a PWM signal forming means, 52 is a voltage converting means, and 83 is an energizing means. is there.

Claims (4)

A permanent magnet motor comprising a rotor having a permanent magnet and a stator provided with a three-phase winding;
Current detecting means for detecting a current of the three-phase winding;
Current conversion means for calculating a magnetic flux axial direction component current (d-axis current) of the permanent magnet motor and a torque axial direction component current (q-axis current) orthogonal thereto from the current of the three-phase winding;
Power calculating means for calculating the power of the permanent magnet motor;
D-axis current command forming means for calculating a d-axis current command based on the power;
Q-axis current command forming means for calculating a q-axis current command based on a current command given from outside;
Voltage calculating means for calculating a d-axis voltage and a q-axis voltage based on the d-axis current command, the q-axis current command, the d-axis current, and the q-axis current;
Induced voltage calculation means for calculating a d-axis induced voltage based on the d-axis current, the q-axis current, and the d-axis voltage;
Angular velocity calculation means for determining the angular velocity of the rotor based on the d-axis induced voltage;
Position estimating means for estimating the rotational position of the rotor based on the angular velocity;
PWM signal forming means for forming a three-phase PWM signal from the d-axis voltage, the q-axis voltage, and the rotational position;
Energization means for energizing the windings of the permanent magnet motor based on the three-phase PWM signal ;
When braking the rotation of the permanent magnet motor, regenerative braking is performed after short-circuit braking is performed for a predetermined time or a predetermined number of revolutions or more, and then a negative current command SI given from the outside at a predetermined number of revolutions or less is supported. And a brake control means for controlling to perform positioning by energizing the three-phase winding . In the regenerative braking, the brake control unit causes the q-axis current command forming unit to form a negative q-axis current command Iqr from the negative current command SI, and the power calculation unit performs the d-axis current, q Power is calculated based on the axial current, the d-axis voltage, and the q-axis voltage, and when the power becomes negative, the d-axis current command forming unit is caused to form a negative d-axis current command Idr. The motor control device according to claim 1. In the positioning, the brake control unit fixes the output of the angle calculation unit by setting the output of the angular velocity calculation unit to zero, and changes the d-axis current command Idr by the d-axis current command forming unit from zero to a current. 3. The motor control device according to claim 1, wherein the absolute value of the command SI is increased, and the q-axis current command Iqr by the q-axis current command forming means is made zero . 4. The motor control device according to claim 1, further comprising low-speed rotation control means for performing low-speed rotation by controlling the angular velocity by forced commutation when an external low-speed command is received .

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