JP2002064991A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost motor controller which can control the torque with higher precision by reducing the variations in of a DC brushless motor itself and temperature change. SOLUTION: A target current setting unit 1 and a current control unit 2 handle the motor 3 by converting it to an equivalent circuit including a first armature located on the q-axis as the magnetic flux direction of field and a second armature crossing the q-axis at the right angle. The target current setting unit 1 comprises a torque compensating means 11 for calculating the amount of torque compensation to adjust the torque of the motor 3 depending on the difference between the target phase power (Pf-c) preset by a current setting map 10 and an actual power (Pf-r) detected by an actual phase power detecting unit 30 based on the actual Id current (Id-s), actual Iq current (Iq-s), the target Vd voltage (Vd-c) and the target Vq voltage (Vq-c), and for compensating for the target Id current (Id-c) as the target value of the Id current flowing into the second armature of the motor with amount of torque compensation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device for controlling an output torque of a DC brushless motor by feeding back a current flowing through an armature of the motor.

[0002]

2. Description of the Related Art Conventionally, as a torque control method of a DC brushless motor, as shown in FIG.
v, w) of a DC brushless motor, a first armature 101 on a q-axis which is a magnetic flux direction of a field magnet provided on the rotor 100 and a second armature 1 on a d-axis orthogonal to the q-axis.
Dq control, which is handled by converting to an equivalent circuit having “02”.

According to the dq control, a control system of a DC brushless motor, which is originally represented by three-phase AC voltage and AC current, can be represented by two-axis (d-axis / q-axis) DC voltage and DC current. Therefore, torque control of the DC brushless motor can be simplified.

[0004] The output torque Tr of the three-phase DC brushless motor is represented by the following equation:
If the current flowing through the armature is Id, it is expressed by the following equation (a).

[0005]

(Equation 1)

Therefore, if the induced voltage constant Ke is constant, the relationship between Id and Tr is mapped in advance, and when a desired torque command is given, the Id current corresponding to the torque command is obtained from the map. Is determined, and the output torque of the DC brushless motor can be controlled by adjusting the voltage applied to the electrodes of the motor such that the Id current matches the target value.

However, actually, the induced voltage constant Ke may change due to individual differences of the motor, temperature change of the field magnet, and the like. When the induced voltage constant Ke changes in this way, an error occurs between the torque command and the actual output torque of the motor, and accurate torque control cannot be performed.

Therefore, conventionally, attention has been paid to the fact that there is a correlation between the output torque of the DC brushless motor and the power consumption, and the power supplied from the power supply of the DC brushless motor (≒ power consumption of the DC brushless motor) and The relationship between the output torque of the DC brushless motor is mapped in advance, and when performing torque control, the difference between the power obtained from the map in accordance with the torque command and the power actually supplied from the power source is eliminated. Then, the target Id current is corrected to perform torque compensation.

However, in order to obtain the power actually supplied from the power supply, it is necessary to provide a voltage sensor for detecting the output voltage of the power supply and a current sensor for detecting the output current of the power supply. And the configuration of the apparatus becomes complicated.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device capable of performing accurate torque control by reducing the effects of individual differences and temperature changes of a DC brushless motor at a reduced cost. With the goal.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a DC brushless motor is provided with a first motor on a q-axis which is a direction of a magnetic field of the motor.
Current detection means for converting an armature and an equivalent circuit having a second armature on the d-axis orthogonal to the q-axis and treating the same, and detecting an armature current that is a current flowing through the armature of the motor; Rotation speed detection means for detecting the rotation speed of the motor,
Power supply voltage detection means for detecting a power supply voltage of the motor;
A target Iq which is a target value of a current flowing through the first armature according to the actual power supply voltage detected by the power supply voltage detecting means, the actual rotational speed detected by the rotational speed detecting means, and a predetermined target torque. Target current determining means for determining a current and a target Id current which is a target value of a current flowing through the second armature; and an actual current flowing through the first armature from a current value detected by the current detecting means. Actual current grasping means for grasping a certain actual Iq current and an actual Id current which is an actual current flowing through the second armature;
voltage control means for controlling a Vq voltage generated in the first armature and a Vd voltage generated in the second armature such that the current Id matches the actual Id and the target Id current. The present invention relates to improvement of a motor control device provided.

Then, based on the target torque, the actual rotation speed, and the actual power supply voltage, a target phase power, which is the sum of the power consumed by the first armature and the power consumed by the second armature, A target phase power determining unit that determines a target phase power as a value, the actual Iq current or the target Iq current, the actual Id current or the target Id current, and the Vq voltage and the Vd voltage by the voltage control unit. From the control voltage value, the power actually consumed by the first armature and the second
Real-phase power grasping means for grasping the real-phase power which is the sum of the power actually consumed by the armature; and torque compensation for adjusting the torque of the motor according to a difference between the real-phase power and the target phase power. And a torque compensating means for calculating the amount and correcting the target Id current with the torque compensation amount.

According to the present invention, as will be described later in detail, when the induced voltage constant of the motor changes due to the individual difference of the motor or a temperature change, the output torque of the motor fluctuates. The real-phase power grasped by the power grasping means changes. The target Id is obtained by the torque compensation amount calculated by the torque compensating means in accordance with a difference between the actual phase power and the target phase power, for example, by feedback processing by PI control.
Since the current is corrected, a change in the output torque of the motor due to a change in the induced voltage constant can be suppressed, and the output torque of the motor can be accurately controlled.

In the case where the induced voltage of the motor includes higher harmonics, the variation of the actual Iq current and the actual Id current detected by the actual current detecting means is large. When it is necessary to perform higher-order moving average processing when grasping the real-phase power, by grasping the real-phase power using the target Iq current or the target Id current, the real-phase power grasping means is The real phase power can be grasped by the moving average processing of a small order. According to the present invention, it is not necessary to newly provide a sensor for detecting the current supplied from the power supply of the motor, and therefore a motor control device capable of performing accurate torque control is provided at a reduced cost. be able to.

The control phase voltage obtained by vector-combining the control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means is the Vq voltage and the Vd voltage which can be actually controlled by the voltage control means. The control phase voltage and the V actually generated in the first armature when the saturation state exceeds the upper limit voltage of the phase voltage obtained by vector synthesis of
a storage unit for storing in advance a correlation between a q voltage and a real phase voltage obtained by vector-synthesizing the Vd voltage generated in the second armature; The real-phase power is obtained by correcting the control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means based on the correlation stored in the storage means.

According to the present invention, when the saturation state occurs and the control phase voltage and the real phase voltage do not match with each other, the real phase power grasping means stores the correlation data stored in the storage means. The control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means is corrected based on the relationship to grasp the actual phase power. Therefore, even in the case of the saturated state, the real-phase power grasping means can grasp the real-phase power with good accuracy.

Further, the magnitude of the control phase voltage obtained by vector-combining the control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means is equal to the Vq voltage which can be actually controlled by the voltage control means. A phase voltage compensator for correcting the target Iq current so as to be equal to or less than a maximum phase voltage set near an upper limit voltage of a phase voltage obtained by vector-combining the Vd voltage and the Vd voltage is provided.

According to the present invention, when the Iq current is corrected by the phase voltage compensating means when the magnitude of the control phase voltage exceeds the maximum phase voltage, the details will be described later. The voltage Vd decreases, the voltage Vq increases, and the magnitude of the control phase voltage decreases below the maximum phase voltage. Therefore, the control phase voltage exceeds the maximum phase voltage and the Id current cannot be controlled,
It is possible to prevent the output torque of the motor from dropping below the target torque.

Further, the rotor of the motor is of a salient pole type having an air gap between field poles, and the torque compensating means is configured to output the Id current and the Id current on a dq coordinate plane including the d axis and the q axis. A first axis having an inclination in a direction in which a change in the output torque of the motor becomes maximum with respect to a change in the predetermined amount of the Iq current, and a phase orthogonal to the first axis, wherein the output torque of the motor is constant and the phase is The second in the direction of the lowest voltage
And setting the torque compensation amount within a range defined by a side of the first axis where the output torque increases and a side of the second axis where the phase voltage decreases in a coordinate system composed of axes. To the dq coordinate plane to calculate a correction amount of the target Id current and a correction amount of the target Iq current according to the torque compensation amount, and calculate the target Id current and the target Iq And correcting the current.

According to the present invention, when the rotor of the motor is the salient pole type, and the output torque of the motor is affected by the Iq current, the coordinate conversion is performed according to the torque compensation amount. The correction amount of the target Iq current and the correction amount of the target Id current are calculated to obtain the target Iq current.
The q current and the Id current can be corrected.

Further, the rotor of the motor is of a salient pole type having an air gap between field poles, and the phase voltage compensating means is provided on the dq coordinate plane including the d axis and the q axis. A first axis having a direction in which a change in the output torque of the motor becomes maximum with respect to a change in a predetermined amount of the Iq current, and an output torque of the motor which is orthogonal to the first axis and has a constant output torque. The second in the direction in which the phase voltage is the lowest
The control phase voltage and the maximum phase voltage within a range defined by a side where the output torque of the first axis decreases and a side where the phase voltage decreases of the second axis in a coordinate system composed of axes. By setting a phase voltage compensation amount calculated according to the difference and performing coordinate conversion from the coordinate system to the dq coordinate plane, the correction amount of the target Id current according to the phase voltage compensation amount and the target The correction amount of the Iq current is calculated to correct the target Id current and the target Iq current.

According to the present invention, when the rotor of the motor has the cylindrical shape and the output torque of the motor is affected by the Iq current, the coordinate conversion is performed according to the phase voltage correction amount. The correction amount of the target Iq current and the correction amount of the target Id current can be calculated to correct the target Iq current and the Id current.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram in a case where torque control of a DC brushless motor is performed by a motor control device of the present invention. FIG. 2 is a control block diagram of a DC brushless motor according to a first embodiment of a target current setting unit.
FIG. 4 is an explanatory diagram of a correction process when the phase voltage of the DC brushless motor is saturated, FIG. 4 is an explanatory diagram of a correction process when the control phase voltage of the motor exceeds the maximum phase voltage, and FIG. 6 is a control block diagram of a DC brushless motor according to the second embodiment, FIG. 6 is a structural explanatory diagram of a rotor of the DC brushless motor, and FIGS. 7 and 9 perform torque compensation and phase voltage compensation for a DC brushless motor having a salient pole-shaped rotor. FIG. 8 is a control block diagram of a DC brushless motor according to a third embodiment of the target current setting unit.
FIG. 10 is an explanatory diagram of dq coordinates.

Referring to FIG. 1, the motor control device of the present invention mainly comprises a target current setting section 1 and a current control section 2. The target current setting unit 1 and the current control unit 2
As shown in FIG. 10, the DC brushless motor 3 (hereinafter, referred to as a motor 3) of the phase (u, v, w) is moved along a q-axis that is a magnetic flux direction of a field 100 of a permanent magnet provided in the motor 3. And a second armature 102 on the d-axis orthogonal to the q-axis.

In the figure, θe is an electric angle which is the angle of the field 100 measured clockwise with respect to the u-phase axis, and ωe is the electric angular velocity of the field 100. Further, the rotor 4 of the motor 3 has a cylindrical shape in which a field pole of a general permanent magnet is embedded in a magnetic material and has no air gap between the field poles as a rotor of a DC brushless motor.

In this equivalent circuit, the second armature 10
The torque of the motor 3 is controlled by adjusting the Id current flowing through the first armature 101 and the Iq flowing through the first armature 101.
By adjusting the current, the magnetic flux of the field poles of the motor 3 is controlled.

The target current setting unit 1 and the current control unit 2
It is an electronic unit composed of U, ROM, RAM, etc., and is output to a target current setting unit 1 from a rotation speed sensor 5 (corresponding to rotation speed detecting means of the present invention) for detecting the rotation speed of the motor 3. And a power supply voltage sensor 7 for detecting an output voltage of the power supply 6 of the motor 3.
The power supply voltage detection signal (PS_s) output from the power supply voltage detection means (corresponding to the power supply voltage detection means of the present invention) and the target torque signal (Tr_c) output from another device are input, and the current setting map 10 (the present invention) The target current determining means (corresponding to the target current determining means) generates the target torque indicated by the target torque signal (Tr_c) so that the target value of the target Id current (Id_c) and the target value of the Iq current are obtained. A certain goal I
q (Iq_c) is determined.

Here, the current setting map 10 shows the rotation speed of the motor 3 obtained from the rotation speed detection signal (Re_s),
When an output voltage of the power supply 5 obtained from the power supply voltage detection signal (PS_s) and a target torque indicated by the target torque signal (Tr_c) are given, an Id current necessary to obtain the target torque is obtained. This is a data map obtained by experimentally obtaining Iq current. Therefore, the target Id current (Id_c) set in the current setting map 10 and the target Id
If the Id current and the Iq current are controlled so that the q current (Iq_c) is supplied to the motor 3, the motor 3 can basically generate the target torque.

However, in practice, the induced voltage constant of the motor 3 may be different from the induced voltage constant when the current setting map 10 is created due to individual differences of the motor 3 and temperature changes of the field poles. Then, the torque T generated by the motor 3
Since r is represented by the above equation (1) when the induced voltage constant is Ke, if the induced voltage constant Ke is different from the value when the current setting map 10 is created, the target torque and the motor 3 are actually generated. An error occurs with the torque.

Therefore, the target current setting unit 1 performs a process of suppressing the error of the torque generated by the motor 3 by the torque compensating unit 11 (including the function of the torque compensating means of the present invention). The phase voltage compensating unit 12 (including the function of the phase voltage compensating means of the present invention) prevents the voltage generated in the capacitor from exceeding the controllable range. The operation of the torque compensator 11 and the phase voltage compensator 12 will be described later.

The current control unit 2 has a current detection signal (Iu_s) output from a current sensor 8a (corresponding to current detection means of the present invention) for detecting a current flowing through the u-phase armature of the motor 3. And a current detection signal (Iw_s) output from a current sensor 8b (corresponding to current detection means of the present invention) for detecting a current flowing through a w-phase armature of the motor 3;
Magnetic pole position sensor 9 for detecting the electric angle of the field pole of motor 3
The position detection signal (θe_s) output from the
The phase / dq converter 20 (corresponding to the actual current grasping means of the present invention) converts I-phase current detection signal (Iu_s), w-phase current detection signal (Iw_s), and position detection signal (θe_s) into Id. The actual Id current (Id_s), which is the current detection value, and I
An actual Iq current (Iq_s) which is a detected value of the q current is calculated.

The actual Id current (Id_s) and the actual Iq current (Iq_s) are calculated together with the target Id current (Id_c) and the target Iq current (Iq_c) output from the target current setting unit 1.
It is input to the dq voltage control section 21 (corresponding to the voltage control means of the present invention). The dq voltage control unit 21 determines that the actual Id current (Id_s) matches the target Id current (Id_c), and
Referring to FIG. 10, target Vq voltage (Vq_c) which is a target value of Vq voltage generated in first armature 101 so that actual Iq current (Iq_s) matches target Iq current (Iq_c).
And a target Vd voltage (Vd_c) that is a target value of the Vd voltage generated in the second armature 102.

The target Vq voltage (Vq_c) and the target Vd voltage (Vd_c) determined by the dq voltage control unit 21 are dq /
The signal is input to the three-phase converter 22, and the dq / 3-phase converter 22
The target Vq voltage (Vq_c) and the target Vd voltage (Vd_c) are set to 3
It is converted to the target voltage of the phase (Vu_c, Vv_c, Vw_c) and output to the motor driver 23. Then, the motor driver 23 outputs voltages (Vu, Vv, Vw) corresponding to the three-phase target voltages (Vu_c, Vv_c, Vw_c) to u,
The voltage is applied to each of the armatures v and w.

By a series of these processes by the current control unit 2, the target Id current (Id_c) is reduced to the actual Id current (Id_s).
And the current flowing through the armature of the motor 3 is feedback-controlled so that the target Iq current (Iq_c) matches the actual Iq current (Iq_s).

Next, a first mode of the target current setting section 1 will be described with reference to FIGS. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

Referring to FIG. 2, the current setting map 10 provided in the target current setting section 1 includes a target Id current (Id_c) and a target Iq current (Iq_c) in addition to the aforementioned target Id current (Id_c). , The phase power Pf which is the sum of the power consumed by the first armature 101 and the power consumed by the second armature 102
Is determined (in this case, the current setting map includes the function of the target phase power determining means of the present invention).

The map data of the target phase power (Pf_c) is
Like the target Id current (Id_c) and the target Iq current (Iq_c), they are set based on data measured by experiments in advance.

Here, Id current (Id) and Iq current (I
q), Vd voltage (Vd) and Vq voltage (Vq)
There is a relationship of the following equation (2).

[0039]

(Equation 2)

By transforming equation (2), the following equation (3) is obtained.

[0041]

[Equation 3]

Therefore, when the induced voltage constant Ke of the motor 3 changes due to the individual difference of the motor 3 or the temperature change of the field pole, the output torque Tr of the motor 3 changes (Equation (1)).
), Target Id current (Id_c) and target Iq current (Iq
_c) to supply the target Vd voltage (Vd_
c, the target Vq voltage (Vq_c, which corresponds to the control voltage value of the Vq voltage of the present invention) changes.

As a result, the actual phase power (Pf_), which is the actual power consumed by the motor 3 calculated by the following equation (4):
r) changes.

[0044]

(Equation 4)

Therefore, the change in the output torque Tr of the motor 3 can be grasped from the change in the actual phase power (Pf_r). Therefore, the torque compensating unit 11 corrects the target Id current (Id_c) according to the difference between the target phase power (Pf_c) and the real phase power (Pf_r) determined from the current setting map 10, thereby outputting the output of the motor 3. A process for suppressing the fluctuation of the torque Tr is performed.

The torque compensating section 11 includes a real-phase power grasping section 30 (corresponding to the real power grasping means of the present invention) for calculating the real-phase power (Pf_r) according to the above equation (4), and an actual power supply voltage (PS).
_s), the upper limit voltage of the phase voltage that can be actually controlled by the dq voltage controller 21 is grasped, and the control phase voltage obtained by vector synthesis of the target Vd voltage (Vd_c) and the target Vq voltage (Vq_c) exceeds the upper limit voltage. When a saturated state is reached, a saturation correction unit 31 that corrects the actual phase voltage (Pf_r), an addition point 32 that takes the difference (ΔPf = Pf_c−Pf_r) between the target phase power and the actual phase power, and ΔPf from the following equation ( 5) The torque compensation amount (ΔI) for adjusting the output torque of the motor 3 according to
d) and a PI calculation unit 33 for calculating the target Id current (I
d_c) to add the torque compensation amount (ΔId) to correct the target Id current, and has an addition point 34.

[0047]

(Equation 5)

Here, the dq voltage controller 21 controls the motor 3
Control that causes the motor 3 to generate a phase voltage exceeding the output voltage of the power supply 6 (see FIG. 1) cannot be performed. Therefore, the real-phase power grasping unit 30 calculates the actual power supply voltage (PS_s)
The upper limit voltage of the phase voltage that can be controlled by the dq voltage control unit 21 is determined based on

Referring to FIG. 3A, control phase voltage (Vf
_c) is equal to or lower than the above-described upper limit voltage (Vf_u) (state in the figure), the current control unit 2 controls the control phase voltage (Vf_c) so that the phase voltage actually applied to the motor 3 matches. Therefore, the real-phase power (Vf_r) calculated by the real-phase power grasping unit 30 substantially matches the phase power actually supplied to the motor 3.

However, when the control phase voltage (Vf_c) is in a saturated state (the state in the figure) exceeding the upper limit voltage (Vf_u), the current exceeds the controllable range of the current control unit 2, so that the control phase voltage (Vf_c) Therefore, the phase voltage applied to the motor 3 is different. As a result, the actual phase power (Vf_r) calculated by the actual power grasping unit 30 does not match the phase power actually supplied to the motor 3, and the phase power cannot be grasped accurately.

FIG. 3B shows the relationship between the control phase voltage (Vf_c) and the detection voltage (Vf_s) of the phase voltage actually applied to the motor 3 when the phase power is saturated. (In the figure), the control phase voltage (Vf_c) is changed to the detection voltage (Vf_c).
_s) is a diagram shown in comparison with an ideal control state (in the figure) that coincides with (_s). As is clear from FIG. 3B, as the saturation state progresses, the difference from becomes larger, and the error of the real-phase power (Pf_r) grasped by the real-phase power grasping unit 30 increases.

Therefore, the saturation correction section 31 stores a map (corresponding to the storage means of the present invention) storing the correlation between the control phase voltage (Vf_c) and the detected phase voltage (Vf_s) in the saturated state shown in FIG. Corresponding to the actual phase power (Pf) calculated by the real phase power grasping unit 30 based on the map.
_r), the real-phase power (Pf_r) can be accurately grasped even in the saturated state.

FIGS. 4A and 4B show the relationship between the current and the voltage on the dq coordinates shown in FIG. 10, where Lq is the inductance of the first armature 101, Lq
d is the inductance of the second armature, R is the first armature 10
The resistance of the first and second armatures 102, ω is the angular velocity of the motor 3, and ωe is the electric angular velocity of the motor 3.

Vmax (corresponding to the maximum phase voltage of the present invention) is a current control unit 2 determined according to the actual power supply voltage PS_s.
This is a voltage set near the upper limit value of the phase voltage obtained by vector-combining the Vd voltage and the Vq voltage that can be controlled by the above.

Here, the voltage V generated in the first armature 101
q and the voltage Vp generated in the second armature 102 are represented by the following equations (6) and (7), respectively.

[0056]

(Equation 6)

[0057]

(Equation 7)

The output torque Tr of the motor 3 increases in the direction of the combined vector V1 of R · Id and ωe · Ld · Id (see FIG. 4A). In this case, for example, when the operating point P1 of the motor 3 is on a circle having a radius of Vmax, I is determined by the above-described torque compensation amount (ΔId).
When the correction for increasing the d current is performed, the phase voltage shifts in the direction of D1 (D1 is parallel to V1), exceeds Vmax, and the operating point is outside the stable circle. When the operating point of the motor 3 goes out of the stable circle, normal current control by the current control unit 2 cannot be performed, and the output torque of the motor 3 may be greatly reduced.

Therefore, when the control phase voltage (Vf_c) exceeds the maximum phase voltage (Vmax), the control phase voltage compensator 12 corrects the control phase voltage (Vf_c) so as to fall within the stable circle. Is performed.

The control phase voltage compensator 12 outputs the actual power supply voltage (P
S_s), a maximum phase voltage setting unit 40 that sets the maximum phase voltage (Vmax), a control voltage grasping unit 41 that calculates a control phase voltage (Vf_r) from the control Vd voltage (Vd_c) and the control Vq voltage (Vq_c), The phase voltage for adjusting the phase voltage of the motor 3 from the addition point 42, which is the difference (ΔVf = Vfmax−Vf_c) between the phase voltage (Vmax) and the control phase voltage (Vf_c), and ΔVf by the following equation (8). Compensation amount (ΔI
q), and a PI calculation unit 43 for calculating the target Iq current (I
q_c) is added to the phase voltage compensation amount (ΔIq) to correct the target Iq current, and has an addition point 44.

[0061]

(Equation 8)

Referring to FIG. 4B, phase voltage compensating section 12
Means that the Id current is increased by ΔId by the torque compensating unit 11,
Accordingly, when the operating point of the motor 3 shifts from P1 to P2 and the operating point of the motor 3 goes out of the stable circle SF, the phase voltage compensation amount (ΔIq ) Is added to the target Iq current at the addition point 44.

Thus, the operating point of the motor 3 is set to the stable circle S
The transition from the point P2 outside F to the point P3 in the stable circle SF prevents the current control of the motor 3 from being disabled, thereby preventing the output torque of the motor 3 from decreasing.

Then, the target Id current (Id_c) corrected by the torque compensator 11 and the target Iq current (Iq_c) corrected by the phase voltage compensator 12 are compared with the current controller 2.
Is output to the dq voltage control unit 21 provided in the.

The dq voltage control section 21 outputs the target Id current (I
d_c) and the actual Id current (Id_s), the addition point 50 that takes the difference (ΔId_c), the PI operation unit 51 that performs the PI operation on ΔId_c, the target Iq current (Iq_c) and the actual Iq current (Iq_c).
s) and the addition point 52 which takes the difference (ΔIq_c), ΔI
A PI calculation unit 53 that performs a PI calculation of q_c, calculates a target Vd voltage (Vd_c) from the Iq current and the angular velocity ω of the motor 3 by decoupling from the calculation results of the PI calculation unit 51, and calculates the calculation result of the PI calculation unit 53. From the target Vq voltage (Vq_c) to Id
A non-interference control unit 54 for generating a non-interference term for decoupling from the current and the angular velocity ω of the motor 3, and a non-interference term calculated by the non-interference control unit 54 in the calculation result of the PI calculation unit 51. The addition point 55 to be added and the PI calculation unit 5
And an addition point 55 for adding the non-interference term calculated by the non-interference control unit 54 to the calculation result of No. 3.

Then, dq / 3 is supplied from dq voltage control section 21.
By outputting the target Vd voltage (Vd_c) and the target Vq voltage (Vq_c) to the phase conversion unit 22, the target Id current (Id_c) becomes the actual Id current (Id_s) as described above with reference to FIG. And the target Iq current (Iq_c) is
The current flowing through the armature of the motor 3 is feedback-controlled so as to match the q current (Iq_c).

Next, a second mode of the target current setting section 1 will be described with reference to FIG. The second embodiment differs from the above-described first embodiment only in the configuration of the real-phase voltage grasping unit 30, and the other configurations are the same.

In the first embodiment described above, the real-phase power grasping unit 30 calculates the real-phase power (Pf_r) according to the equation (1). However, when higher-order harmonics are included in the induced voltage of the motor 3, the dispersion of the actual Id current (Id_s) and the actual Iq current (Iq_s) increases, and the target Vd voltage (Vd_c) and Target Vq voltage (Vq_
The variation in c) also increases.

In this case, in order to stably calculate the real-phase power (Pf_r), a process of performing a higher-order moving average is required, and there is a disadvantage that a response is delayed and a calculation time is increased. Therefore, in the second embodiment, the real-phase power grasping unit 30 calculates the real-phase power (Pf_r) by the following equation (9).
Is calculated.

[0070]

(Equation 9)

That is, the actual Id current (Id_s) and the actual Iq
Real-phase power (Pf_r) based on target Id current (Id_c) and target Iq current (Iq_c) instead of current (Iq_s)
Is calculated. This makes it possible to calculate the real-phase power (Pf_r) having a small variation by a moving average having a small order.

Next, a third mode of the target current setting section 1 will be described with reference to FIGS.

As shown in FIG. 6A, when the rotor 71 of the motor is a salient pole type having an air gap between the field poles 71a and 72b, the field poles 71a and 71b and the armatures 72a and 72b Since the gap (Ga) between them changes according to the rotational position of the rotor 70 (the gap is maximum at the position and the gap is minimum at the position), the magnetic resistance between the armatures 72a and 72b changes accordingly. .

Therefore, as shown in FIG. 6B, the rotor 75 is a rotor of a DC brushless motor, and the field poles 76a and 76b are embedded in a magnetic material (iron or the like) 77 so that the field poles 76a and 76b are A reluctance torque TL is generated which is not generated in the case of a cylindrical shape in which there is no air gap between 76b and the gap (Gb) between armatures 78a, 78b and rotor 75 is constant.

Here, the reluctance torque TL is expressed by the following equation (10), and the output torque Ti of a motor having a salient-pole rotor is expressed by the following equation (11).

[0076]

(Equation 10)

[0077]

(Equation 11)

Therefore, when the rotor shown in the above equation (1) is a salient-pole type motor, the output torque of the motor is determined only by the Id current, but when the rotor is a cylindrical type motor, the Id current and the The output torque of the motor is determined by both the Iq current.

Therefore, as in the first and second embodiments of the target current setting unit 1 described above, the target phase power (Pf
_c) and the actual phase power (Pf_r) cannot be used for torque compensation based on the Id current alone. Further, since the output torque of the motor fluctuates when the Iq current changes, when the actual phase voltage (Vf_r) of the motor exceeds the maximum phase voltage (Vfmax), the difference between the maximum phase voltage (Vmax) and the real phase voltage (Vf_r) is obtained. The phase voltage compensation based on the difference (ΔVf) cannot be performed only by the Iq current.

Therefore, in the third embodiment, the target current setting section 1 decouples the motor torque from the phase voltage in accordance with the difference (ΔPf) between the target phase power (Pf_c) and the actual phase power (Pf_c). In order to compensate the motor phase voltage by decoupling the torque from the torque according to the difference (ΔVf) between the maximum phase voltage (Vfmax) and the control phase voltage (Vf_r), the following coordinate conversion processing is performed.

From the above equation (11),

[0082]

(Equation 12)

[0083]

(Equation 13)

Therefore, with respect to a certain operating point (Id, Iq) of the motor having the salient pole type rotor, the amount of torque change per unit current (corresponding to the predetermined current of the present invention) of the Id current and the Iq current Is the coordinate value Idu1 (V
dqu coordinate), Iqu1 (Vq coordinate)

[0085]

[Equation 14]

Is given by

The coordinate values Idu4 (Vd-axis coordinates) and Iqu4 (Vq-axis coordinates) of the unit current vector in which the torque does not change are:

[0088]

(Equation 15)

Is given by

When these coordinates are expressed as vectors on the dq coordinates, as shown in FIG. 7A, the vector Ut in the normal direction of the isotorque curve TC of the rotor having the salient pole type motor is obtained.
And a tangential vector Uv. Ut is a vector in a direction in which the torque change at the operating point (P10) of the motor is the largest, and Uv is a vector in a direction in which the torque does not change. Further, the Tr axis passes through the operating point (P10), and the inclination is U
The axis equal to t and the Vf axis are axes orthogonal to the Tr axis and at which the change in the phase voltage of the motor is minimized.

From the above, in order to perform the torque compensation and the phase voltage compensation of the motor having a salient pole type rotor in a non-interfering manner as in the case of the motor having a cylindrical rotor, the above equation (5) is used.
Is defined as ΔT, and the phase voltage compensation amount (ΔId) calculated by the above equation (8) is set as ΔT.
q) is set to ΔVf, and the coordinate conversion by the following equation (16) is performed to determine the correction amount (ΔId) of the Id current and the correction amount (ΔIq) of the Iq current for the salient-pole type motor. Good.

[0092]

(Equation 16)

By performing the coordinate conversion in this manner, as shown in FIG. 7A, the torque compensation amount ΔT set on the Tr axis is converted into a dq coordinate value, and the torque compensation amount ΔT
The correction amount (ΔId) of the Id current and the correction amount (ΔIq) of the Iq current required to obtain the following equation can be obtained. Similarly, in the case of the phase voltage operation amount (ΔVf), the phase voltage compensation amount (ΔVf) set on the Vf axis is converted into a dq coordinate value, and the Id current necessary to obtain the phase voltage compensation amount (ΔVf) And the correction amount (Δq) of the Iq current can be obtained.

It is to be noted that the torque compensation amount ΔT is not set on the Tr axis, but on the side where the output torque of the motor on the Tr axis increases (the (+) side in the figure) and on the side where the phase voltage of the motor on the Tf axis decreases (in the figure). (− Side), the correction amount of the Id current (ΔId) and the correction amount of the Iq current (ΔIq) required to obtain the torque compensation amount ΔT can be obtained. Good. Also, the phase voltage compensation amount ΔVf is not set on the Vf axis, but on the side where the output torque of the motor on the Tr axis decreases ((−) side in the figure) and on the side where the phase voltage of the motor on the Tf axis decreases ((− ) Side), the correction amount of the Id current (ΔId) and the correction amount of the Iq current (ΔIq) required to obtain the torque compensation amount ΔT may be obtained.

FIG. 8 shows the configuration of the torque compensating unit 11 and the phase voltage compensating unit 12 in the case where the torque compensation and the phase voltage compensation are performed on the motor 80 having the salient pole type rotor by the above equation (16). It is a thing. The torque compensating unit 12 performs coordinate transformation of the torque compensation amount ΔT by the coordinate transformation unit 70 using the above equation (16), and outputs a correction value (ΔId) of the Id current and a correction value (ΔIq) of the Iq current. Further, the phase voltage compensator 1
2, the coordinate conversion unit 70 performs coordinate conversion on the phase voltage manipulated variable ΔVf using the above equation (16), and corrects the Id current by the correction value (Δ
Id) and the correction value (ΔIq) of the Iq current are output.

As described above, by performing the coordinate transformation by the coordinate transformation unit 70, the torque compensation processing by the torque compensation unit 11 and the phase voltage compensation processing by the phase voltage compensation unit 12 can be performed without interference.

If the stability of the phase power feedback by the torque compensator 11 and the stability of the phase voltage feedback by the phase voltage compensator 12 are not sensitive to a change in the gain of the coordinate converter 70, the above equation (16) is used. ) Can be sufficiently controlled by approximating the following equation (17).

[0098]

[Equation 17]

The maximum output point of the phase voltage is shown in FIG.
As shown in (1), the point where the isotorque curve TC and the voltage circle SF come into contact with each other (P11 in the figure) is a boundary (L1 in the figure) of the phase voltage feedback stable region. Therefore, the feedback of the phase voltage may become unstable around the operating point P11. In this case, ΔL (= L
By performing the coordinate transformation with d-Lq) larger than the actual value, the output limit can be set within the stable region. In the figure, FV2 is the direction in which the torque does not change when ΔL is increased, and L2 is the boundary of the enlarged stable region.

In this case, the coordinate conversion equation is as follows:
8).

[0101]

(Equation 18)

Further, with respect to the operating point (Id, 0) of the motor 80 when Iq = 0, the coordinate value Idu3 (Vd3) in the direction in which the amount of change in torque per unit current of the Id current and the Iq current is largest. Axis coordinates), Iqu3 (Vq axis coordinates)
Is

[0103]

[Equation 19]

The coordinate values Idu4 (Vd-axis coordinates) and Iqu4 (Vq-axis coordinates) of the unit current vector in which the torque does not change are:

[0105]

(Equation 20)

Can be calculated. FIG. 9 illustrates this. TC1, TD1, FD1, and LQ1 are I
The graph shows the isotorque curve when q ≠ 0, the direction in which the torque changes most with respect to the unit current, the direction in which the phase voltage decreases at a constant torque, and the stability limit of the phase voltage feedback. TC2, TD2, FD2, and LQ2 are respectively Iq
Isotorque curve when = 0, direction in which torque changes most with respect to unit current, direction in which phase voltage decreases at constant torque,
The stability limit of the phase voltage feedback is shown.

As is clear from FIG. 9, the stable region is expanded when Iq = 0 compared to the case where Iq ≠ 0. Therefore, the coordinate transformation may be performed approximately using Equations (19) and (20). The coordinate conversion formula in this case is as shown in the following formula (21).

[0108]

(Equation 21)

In this embodiment, the saturation correction unit 31
Holds the correlation between the control phase voltage (Vf_c) and the detected phase voltage (Vf_s) shown in FIG. 3B as a map.
For example, you may hold | maintain by a relational expression.

In the first mode of the target current setting section 1 described above, the real-phase power grasping section 30 outputs the real Id current (Id_
s) and the actual Iq current (Iq_s) based on the actual phase power (P
f_r), and in the second mode of the target current setting unit 1, the real-phase power grasping unit 30 calculates the target Id current (Id_c) and the target I
Although the real-phase power (Pf_r) was calculated based on the q current (Iq_c), the real Id current (I
d_s) and the target Iq current (Iq_c), the real-phase power may be calculated, or the real-phase power (Pf_r) may be calculated based on the target Id current (Id_c) and the real Iq current (Iq_s). .

In this embodiment, the saturation correction unit 31
, The phase voltage is corrected by the phase voltage compensator 12 and the phase voltage is corrected by the phase voltage compensator 12, but the effects of the present invention can be obtained even when these corrections are not performed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram when torque control of a DC brushless motor is performed by a motor control device of the present invention.

FIG. 2 is a control block diagram of a DC brushless motor according to a first embodiment of a target current setting unit.

FIG. 3 is an explanatory diagram of a correction process when a phase voltage of a DC brushless motor is saturated.

FIG. 4 is an explanatory diagram of a correction process when a target phase voltage exceeds a maximum phase voltage.

FIG. 5 is a control block diagram of a DC brushless motor according to a second embodiment of the target current setting unit.

FIG. 6 is a structural explanatory view of a rotor of the DC brushless motor.

FIG. 7 is an explanatory diagram of coordinate conversion for performing torque compensation and phase voltage compensation on a DC brushless motor whose rotor has salient poles.

FIG. 8 is a control block diagram of a DC brushless motor in a third mode of the target current setting unit.

FIG. 9 is an explanatory diagram of coordinate conversion for performing torque compensation and phase voltage compensation for a DC brushless motor whose rotor has salient poles.

FIG. 10 is an explanatory diagram of dq coordinates.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Target current setting part, 2 ... Current control part, 3 ... DC brushless motor, 4 ... Rotor, 5 ... Rotation speed sensor, 6 ... Power supply, 7 ... Power supply voltage sensor, 8a, 8b ... Current sensor, 9
... magnetic pole position sensor, 10 ... current setting map, 11 ... torque compensator, 12 ... phase voltage compensator, 20 ... 3 phase / dq converter, 21 ... dq voltage controller, 22 ... dq / 3 phase converter,
23 ... motor driver, 30 ... real-phase power grasping unit, 31 ...
Saturation correction unit, 40: maximum phase voltage setting unit, 41: target phase voltage grasping unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor, Shokichi Asami 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Yoshinobu Hasuka 1-4-4 Chuo, Wako-shi, Saitama No. 1 F term in Honda R & D Co., Ltd. (Reference) 5H560 BB04 BB12 BB17 DA00 DB00 DC12 DC13 EB01 EB07 RR10 SS01 TT11 TT15 XA02 XA13 5H576 BB06 CC01 DD02 DD05 EE01 JJ03 JJ25 LL01 LL22 LL24 LL41

Claims (5)

[Claims] 1. An equivalent circuit comprising a DC brushless motor having a first armature on a q-axis which is a direction of a magnetic field of the motor and a second armature on a d-axis orthogonal to the q-axis. Current detection means for detecting an armature current that is a current flowing through the armature of the motor, rotation speed detection means for detecting the rotation speed of the motor, and a power supply for detecting a power supply voltage of the motor Voltage detection means, a target of a current flowing through the first armature according to an actual power supply voltage detected by the power supply voltage detection means, an actual rotation speed detected by the rotation speed detection means, and a predetermined target torque. A target current determining means for determining a target Iq current as a value and a target Id current as a target value of a current flowing through the second armature; and a current value detected by the current detecting means to the first armature. Is the actual current that flows Actual current grasping means for grasping an Iq current and an actual Id current which is an actual current flowing through the second armature; and wherein the actual Iq current matches the target Iq current, and the actual Id current is equal to the target Id. A motor control device including voltage control means for controlling a Vq voltage generated in the first armature and a Vd voltage generated in the second armature so as to coincide with a current; And determining the target phase power as the target value of the phase power, which is the sum of the power consumed by the first armature and the power consumed by the second armature, from the actual power supply voltage Means, from the actual Iq current or the target Iq current, the actual Id current or the target Id current, and the control voltage values of the Vq voltage and the Vd voltage by the voltage control means. Actually erase Real-phase power grasping means for grasping real-phase power, which is the sum of the power consumed and the power actually consumed by the second armature; and the motor of the motor according to a difference between the real-phase power and the target phase power. A motor control device comprising: a torque compensation unit that calculates a torque compensation amount for adjusting a torque, and corrects the target Id current based on the torque compensation amount. 2. A control phase voltage obtained by vector-synthesizing the control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means, the Vq voltage and the Vd voltage which can be actually controlled by the voltage control means. The control phase voltage, the Vq voltage actually generated in the first armature, and the Vd voltage generated in the second armature when the saturation state exceeds the upper limit voltage of the phase voltage obtained by vector synthesis of And a storage means for storing in advance a correlation with a real-phase voltage obtained by vector-synthesizing, the real-phase power grasping means, when the saturated state is reached, based on the correlation stored in the storage means. 2. The motor control device according to claim 1, wherein the control unit corrects the control voltage of the Vq voltage and the control voltage of the Vd voltage to determine the actual phase power. 3. The magnitude of a control phase voltage obtained by vector combining the control voltage of the Vq voltage and the control voltage of the Vd voltage by the voltage control means is equal to the Vq voltage that the voltage control means can actually control. 2. The apparatus according to claim 1, further comprising: a phase voltage compensator for correcting the target Iq current so as to be equal to or less than a maximum phase voltage set near an upper limit voltage of a phase voltage obtained by vector-combining the Vd voltage and the Vd voltage. Item 4. The motor control device according to any one of items 3. 4. The motor according to claim 1, wherein the rotor of the motor is a salient pole type having an air gap between field poles, and the torque compensating means is configured to output the Id current and the Id current on a dq coordinate plane including the d axis and the q axis. A first axis having an inclination in a direction in which a change in the output torque of the motor becomes maximum with respect to a change in the predetermined amount of the Iq current, and a phase orthogonal to the first axis, wherein the output torque of the motor is constant and the phase is The torque compensation amount falls within a range defined by a side of the first axis in which the output torque increases and a side of the second axis in which the phase voltage decreases in a coordinate system including a second axis in a direction in which the voltage is lowest. By performing coordinate transformation from the coordinate system to the dq coordinate plane, a correction amount of the target Id current and a correction amount of the target Iq current according to the torque compensation amount are calculated,
4. The motor control device according to claim 1, wherein the target Id current and the target Iq current are corrected. 5. 5. The motor according to claim 1, wherein the rotor of the motor is of a salient pole type having an air gap between field poles, and the phase voltage compensating means is provided on the dq coordinate plane including the d axis and the q axis. A first axis having a direction in which a change in the output torque of the motor becomes maximum with respect to a change in a predetermined amount of the Iq current, and an output torque of the motor which is orthogonal to the first axis and has a constant output torque. In the coordinate system including the second axis in the direction in which the phase voltage is lowest, the control is performed within a range defined by the side where the output torque of the first axis decreases and the side where the phase voltage decreases of the second axis. The phase voltage compensation amount calculated according to the difference between the phase voltage and the maximum phase voltage is set, and the coordinate conversion from the coordinate system to the dq coordinate plane is performed. Calculating the correction amount of the target Id current and the correction amount of the target Iq current 4. The motor control device according to claim 3, wherein the target Id current and the target Iq current are corrected.