JP2003088156A - Controller of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which can obtain a high motor efficiency. SOLUTION: In this controller of a brushless motor, a PWM control circuit 1 has a revolution detecting circuit 14 which detects a revolution ω of the motor; a position calculation circuit 15 which takes out a rotation angle θof the motor; a voltage command control circuit 12 which generates a voltage command signal V* according to a sine wave function expressing a voltage command signal with the rotation angle θ, a phase lead angle ψ, and a voltage amplitude command Va as variables; and a PWM signal generating circuit 13 which generates a PWM signal according to the voltage command signal V*. The voltage command control circuit 12 has a phase lead angle taking-out circuit 12a which, after a voltage phase lead angle ψo for a reference load weight is taken out according to the revolution ω of the motor, corrects the phase lead angle ψo according to the voltage amplitude command Va to take out a phase lead angle ψ corresponding to a load weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor control device including an inverter for supplying AC power to a brushless motor and a PWM control circuit for controlling the inverter.

[0002]

2. Description of the Related Art Conventionally, a brushless motor has been used as a motor for driving a pulse eater of a washing machine.
FIG. 10 shows a configuration example of a brushless motor control device. AC power from the commercial power supply (4) is rectified
After being converted into DC power by (5), it is converted into AC power by the inverter (6), and the AC power is supplied to the brushless motor (2) to drive the motor. The brushless motor (2) is provided with position sensors (3) consisting of Hall elements at three positions with a phase difference of 120 degrees on the circumference around the rotation axis.
Three position signals (Hu, Hv, Hw) obtained from the three position sensors (3), (3) and (3) are supplied to the PWM control circuit (9), and the inverter (6) is operated by the PWM control circuit (9). Controlled.

FIG. 11 shows the configuration of the PWM control circuit (9). The three position signals (Hu, Hv, Hw) obtained from the position sensor are supplied to the position calculation circuit (95) and the rotation speed detection circuit (94). In the rotation speed detection circuit (94), three position signals (Hu, Hv,
The rotation speed ω of the motor is detected based on (Hw), and the result is supplied to the phase advance angle derivation circuit (92a) and the position calculation circuit (95) which form the voltage command control circuit (92). The position calculation circuit (95) calculates the rotation angle θ of the motor based on the three position signals (Hu, Hv, Hw) and the rotation speed ω, and the calculated rotation angle θ is calculated by the voltage command control circuit ( It is supplied to the voltage command signal generation circuit (92b) that constitutes the circuit 92). The phase advance angle deriving circuit (92a) derives a phase advance angle ψ described later based on the rotation speed ω. Here, when the load weight is constant, a constant relationship is established between the rotation speed of the brushless motor and the phase advance angle ψ, and the load angle is set to an arbitrary constant value in the phase advance angle deriving circuit (92a). A table or a functional expression representing the above relation when the value is stored. The phase advance angle deriving circuit (92a) derives the phase advance angle ψ from the rotation speed ω obtained from the rotation speed detection circuit (94) based on these tables or functional expressions. The derived phase advance angle ψ is supplied to the voltage command signal generation circuit (92b).

Rotational speed ω obtained from the rotational speed detection circuit (94)
Is supplied to the rotation speed control circuit (91), and in the circuit (91),
The voltage amplitude command Va is created based on the deviation of the motor speed from the target value ω *. The voltage amplitude command Va is supplied to the voltage command signal generation circuit (92b), and in the circuit (92b), the voltage amplitude command V obtained from the rotation speed control circuit (91).
Based on a, the phase advance angle ψ obtained from the phase advance angle deriving circuit (92a), and the rotation angle θ obtained from the position calculation circuit (95), the voltage command signal for the U phase of the brushless motor is calculated from the following formula 1. Vu * is calculated.

[0005]

[Formula 1] Vu * = Va · cos (θ + ψ)

1 for the U-phase voltage command signal Vu *
By giving a phase difference of 20 ° and 240 °, a V phase voltage command signal Vv * and a W phase voltage command signal Vw * are created, and these three phase voltage command signals (Vu *, Vv *, V
w *) is supplied to the PWM signal generation circuit (93) to generate U
PWM signals for the phase, the V phase, and the W phase are created.

The U-phase, V-phase, and W-phase PWM signals thus created are supplied to the inverter (6) shown in FIG. 10, and the inverter (6) is PWM-controlled. As a result,
The brushless motor (2) will be driven. Above P
In the WM control circuit (9), as described above, the phase of the voltage command signal is advanced by the phase advance angle ψ so that the phase of the current flowing in the winding matches the phase of the induced voltage generated in the winding. As a result, the motor efficiency is improved.

[0008]

However, in the conventional PWM control circuit (9), although the load weight fluctuates during the driving of the motor, the load weight is not calculated when the phase advance angle ψ is derived. Is always used, and the same phase advance angle ψ is always derived if the rotational speed ω of the brushless motor is the same.

FIG. 12 shows the phases of the voltage V applied to the motor and the current I flowing through the winding. Figure (a)
(b) and (c) are applied voltages V when the rotation speed ω of the motor is the same, with the direction of the magnetic flux generated from the permanent magnet of the brushless motor as the d-axis and the direction orthogonal to the magnetic flux direction as the q-axis. And the phase of the current I. The figure (a) shows the phase of the applied voltage V and the current I when the load weight has the same value as the above-mentioned constant value, and the figure (b) shows the load weight. Is a phase of the applied voltage V and the current I when the load weight is smaller than the arbitrary constant value, and FIG. 7C shows the applied voltage V and the current I when the load weight is smaller than the arbitrary constant value. Represents the phase. According to the above-mentioned conventional PWM control circuit (9), as described above, the same phase advance angle ψ is given in any of the cases (a), (b) and (c) of FIG.

When a voltage V is applied to the motor, a current I flows in the winding, and an induced voltage (ω · φ) due to the interlinkage magnetic flux φ, a voltage (R · I) due to the resistance R of the winding and the winding A voltage (ω · L · I) due to the inductance L of is generated in the winding. When the load weight is the same as the above-mentioned arbitrary constant value, the phase of the current I flowing through the winding is the induced voltage (ω ·
The current component in the d-axis direction that does not contribute to the torque generation does not occur in agreement with the phase of φ). On the other hand, when the load weight exceeds the above given constant value, the phase of the current I flowing through the winding lags behind the phase of the induced voltage (ω / φ) as shown in FIG. A current component in the d-axis direction that does not contribute to the occurrence of Further, when the load weight is reduced below the above given constant value, the phase of the current I flowing through the winding leads the phase of the induced voltage (ω / φ) as shown in FIG.
A current component in the d-axis direction that does not contribute to the generation of torque is generated.

As described above, in the conventional PWM control circuit (9), when the load weight is the same value as the above-mentioned arbitrary constant value, the phase of the current I flowing through the winding is as shown in FIG. 12 (a). There is no generation of a current component that does not contribute to torque generation in synchronism with the phase of the induced voltage (ω ・ φ) generated in the winding, but the load weight increases or decreases below the above given constant value. Then, as shown in (b) and (c) of the same figure, the phase of the current I deviates from the phase of the induced voltage (ω · φ), and a current component that does not contribute to the generation of torque is generated, which reduces the motor efficiency. There was a problem.

Therefore, an inverter device has been proposed which determines the voltage phase command from the motor rotation speed and the voltage command based on a table showing the relationship between the motor rotation speed, the voltage command and the voltage phase command (special feature: Kaihei 10-146090 [H02P 6 /
18]). However, in the inverter device, since the table used when determining the voltage phase command is a complicated one that expresses the relationship between the three types of parameters, there is a problem that the arithmetic processing at that time becomes complicated.

An object of the present invention is to provide a motor control device which can obtain high motor efficiency.

[0014]

A first brushless motor controller according to the present invention includes an inverter for supplying AC power to the brushless motor, and a P for controlling the inverter.
WM control circuit. Here, the PWM control circuit includes a speed detection unit that detects a rotation speed of the brushless motor, an angle detection unit that detects a rotation angle of the brushless motor, a rotation angle of the brushless motor, a voltage phase advance angle, and a voltage amplitude command value. Is used as a variable to generate a voltage command signal based on a function representing a change in the voltage command signal, and PWM based on the created voltage command signal.
Signal processing means for generating a signal and supplying the PWM signal to the inverter. The arithmetic processing means is detected according to the phase advance angle relationship storage means that stores the relationship between the rotational speed of the brushless motor and the voltage phase advance angle, and the relationship stored in the phase advance angle relationship storage means. Phase advance angle deriving means for deriving the voltage phase advance angle from the rotation speed, and correction processing means for correcting the derived voltage phase advance angle based on the voltage amplitude command value or a value corresponding to the voltage amplitude command value. And signal producing means for producing a voltage command signal from the detected rotation angle, the correction phase advance angle obtained from the correction processing means, and the voltage amplitude command value based on the function.

In the first brushless motor control device according to the present invention, first, the voltage phase advance angle is derived from the rotation speed of the brushless motor in accordance with the relationship stored in the phase advance angle relationship storage means, and thereafter. The correction processing means corrects the derived voltage phase advance angle. Here, when the load weight is constant, a constant relationship is established between the rotation speed of the motor and the voltage phase advance angle to be given to the voltage command signal, and this relationship is expressed by, for example, a table or a functional formula. You can Based on these tables or functional formulas, the voltage phase advance angle at the reference load weight is derived. Then, the voltage phase advance angle is corrected based on the voltage amplitude command value or a value corresponding to the voltage amplitude command value. Here, the voltage amplitude command value increases as the load weight increases, and decreases as the load weight decreases. Therefore,
If the voltage phase advance angle is corrected in accordance with the voltage amplitude command value or a value corresponding to the voltage amplitude command value, when the load weight is larger than the reference load weight, the voltage phase advance angle at the reference load weight is increased. A larger voltage phase advance angle can be obtained. Further, when the load weight is smaller than the reference load weight, it is possible to obtain a voltage phase advance angle smaller than the voltage phase advance angle at the reference load weight. In this way, the phase of the voltage command signal (voltage phase) can be advanced by an appropriate voltage phase advance angle according to the load weight. Therefore, regardless of the load weight, it is possible to always match the phase of the current flowing in the winding with the phase of the induced voltage generated in the winding to prevent the generation of a current component that does not contribute to the generation of torque. Therefore, high motor efficiency can be obtained. Further, it is possible to derive the voltage phase advance angle according to the load weight by a simple arithmetic process without using a complicated table like the conventional inverter device.

Specifically, the arithmetic processing means stores a coefficient relation storage in which a relation between the voltage amplitude command value or a value corresponding to the voltage amplitude command value and a correction coefficient used for correcting the voltage phase advance angle is stored. The correction processing means derives a correction coefficient from the voltage amplitude command value or a value corresponding to the voltage amplitude command value according to the relationship stored in the coefficient relationship storage means, and the derived voltage The phase advance angle is calculated using the correction coefficient to calculate the corrected phase advance angle.

As described above, the voltage amplitude command value increases as the load weight increases. Further, as the load weight increases, it is necessary to further advance the phase of the voltage command signal.
Therefore, a relationship is established between the voltage amplitude command value and the voltage phase advance angle to be given to the voltage command signal, in which the voltage phase advance angle increases as the voltage amplitude command value increases. In this way, since a constant relationship is established between the voltage amplitude command value and the voltage phase advance angle to be given to the voltage command signal, the voltage amplitude command value or a value corresponding to the voltage amplitude command value and the voltage phase advance A certain relationship is established with the correction coefficient used to correct the angle. Therefore, in the above-described specific configuration, the relationship between the voltage amplitude command value or the value corresponding to the voltage amplitude command value and the correction coefficient is stored in the coefficient relationship storage means. Here, such a relationship is represented by, for example, a table or a functional expression. When deriving the voltage phase advance angle, a correction coefficient corresponding to the load weight is derived from the voltage amplitude command value or a value corresponding to the voltage amplitude command value according to the relationship stored in the coefficient relationship storage means. If the voltage phase lead angle at the reference load weight is corrected using such a correction coefficient, the voltage phase lead angle according to the load weight can be obtained.

The tables and functional expressions stored in the phase advance angle relationship storage means represent the relationship between the two parameters of the motor rotation speed and the voltage phase advance angle. Further, the table and the functional expression stored in the coefficient relation storage means represent the relationship between the voltage amplitude command value or a value corresponding to the voltage amplitude command value and two types of parameters of the correction coefficient. Therefore, these tables and functional expressions are simpler than the conventional tables showing the relationship between the three types of parameters. In this way, the voltage phase advance angle and the correction coefficient at the reference load weight are derived in accordance with a simple table or functional expression, and the calculation using the correction coefficient is performed on the voltage phase advance angle to obtain the load weight. A corresponding voltage phase advance angle is derived. Therefore, as compared with the conventional inverter device having a complicated table, the calculation process for deriving the voltage phase advance angle according to the load weight becomes simpler.

Further, specifically, the correction processing means calculates the corrected phase advance angle by multiplying the derived voltage phase advance angle by the derived correction coefficient.

In the above specific configuration, the correction coefficient for the reference load weight is set to 1, and the relationship in which the correction coefficient changes in accordance with the change in the voltage amplitude command value or the value corresponding to the voltage amplitude command value is stored in the coefficient relationship store. Stored in the means. In the voltage phase advance angle correction processing, the voltage phase advance angle at the reference load weight is multiplied by the correction coefficient derived based on the above relationship. Here, when the load weight is the reference load weight, a value of 1 is derived as the correction coefficient, and the same voltage phase advance angle as the reference load weight is calculated. When the load weight exceeds the reference load weight, a correction coefficient larger than 1 is derived, and a voltage phase advance angle larger than the voltage phase advance angle at the reference load weight is calculated. On the other hand, when the load weight is smaller than the reference load weight, a correction coefficient smaller than 1 is derived, and a voltage phase advance angle smaller than the voltage phase advance angle at the reference load weight is calculated. In this way, an appropriate voltage phase advance angle according to the load weight is calculated.

More specifically, the PWM control circuit is
Comprising a speed control means for deriving a voltage amplitude command value based on a deviation between the detected rotation speed and the target rotation speed, the correction processing means of the arithmetic processing means is a voltage amplitude command value derived by the speed control means. The voltage phase advance angle is corrected based on

In the above specific structure, the voltage amplitude command value for causing the rotation speed of the brushless motor to follow the target rotation speed is derived, and the rotation speed of the brushless motor is controlled. When the load weight increases, the rotation speed of the brushless motor decreases, and a larger voltage amplitude command value is derived in order to increase the magnitude of the current flowing through the winding.On the other hand, when the load weight decreases, the brushless motor The rotation speed increases and a smaller voltage amplitude command value is derived in order to reduce the magnitude of the current flowing through the winding. In this way, by correcting the voltage phase advance angle at the reference load weight according to the voltage amplitude command value that changes according to the change of the load weight, the voltage phase advance angle according to the load weight can be obtained. According to the above specific configuration, since the voltage amplitude command value derived by the speed control means is used as the parameter for correcting the voltage phase advance angle, an arithmetic processing circuit for calculating the parameter is unnecessary. Is.

Alternatively, specifically, the arithmetic processing means calculates the signal component of the voltage command signal generated by the signal generating means on the basis of the voltage amplitude command value and the correction advance angle calculated by the correction processing means. Among them, the correction processing means comprises a component calculating means for calculating the magnitude of the component in the direction of the magnetic flux generated from the magnets constituting the brushless motor, or the magnitude of the component in the direction orthogonal to the direction of the magnetic flux. The voltage phase advance angle is corrected based on the magnitude of the magnetic flux direction component or the magnitude of the orthogonal direction component calculated by the calculating means.

When the load weight increases, in order to increase the magnitude Iq of the q-axis direction component, which contributes to the generation of torque, among the components of the current I flowing through the winding, the voltage command signal V * d is increased.
Axial component magnitude Vd * and q-axis component magnitude V
q * increases. In this way, according to the magnitude Vd * of the d-axis direction component (magnetic flux direction component) or the q-axis direction component (orthogonal direction component) of the voltage command signal V *, which fluctuates according to the change of the load weight. By correcting the voltage phase advance angle at the reference load weight, the voltage phase advance angle according to the load weight can be obtained.

A second brushless motor control apparatus according to the present invention comprises an inverter for supplying AC power to the brushless motor, and a PWM control circuit for controlling the inverter. Here, the PWM control circuit includes a speed detection unit that detects a rotation speed of the brushless motor, an angle detection unit that detects a rotation angle of the brushless motor, a rotation angle of the brushless motor, a voltage phase advance angle, and a voltage amplitude command value. A calculation processing means for creating a voltage command signal based on a function representing the change of the voltage command signal, and a PWM signal based on the created voltage command signal,
Signal processing means for supplying the PWM signal to the inverter. Among the signal components of the voltage command signal, the arithmetic processing means is based on the deviation between the magnitude of the component in the direction orthogonal to the direction of the magnetic flux generated from the magnets forming the brushless motor and the target value of the orthogonal component. A signal for creating a voltage command signal from the detected rotation angle, the derived voltage phase advance angle, and the voltage amplitude command value based on the function. It is equipped with a creation means.

The magnitude Vq of the q-axis direction component of the voltage V applied to the motor is the magnitude of the voltage due to the inductance L of the winding.
(ω ・ L ・ Id) and voltage magnitude due to winding resistance R
(R · Iq) and the magnitude of the induced voltage due to the flux linkage φ (ω
・ It is given as the sum of φ). Where inductance L
Is a voltage generated by the d-axis direction component of the current I flowing through the winding, and the d-axis direction component is a current component that does not contribute to the generation of torque. Therefore, the current I flowing in the winding
Of the applied voltage V when the magnitude Id of the component in the d-axis direction is zero, that is, the magnitude of the voltage due to the resistance R (R · Iq) and the magnitude of the induced voltage due to the interlinking magnetic flux φ. It
The sum of (ω ・ φ) (R ・ Iq + ω ・ φ) is the voltage command signal V
It is set as a target value Vq ** of the q-axis direction component (orthogonal direction component) of *. Here, the magnitude Iq of the q-axis direction component of the current I flowing through the winding fluctuates according to the fluctuation of the load weight, but the fluctuation is slight. The magnitude of the voltage (R · Iq) due to the resistance R is the magnitude of the induced voltage due to the interlinkage magnetic flux φ.
The value is sufficiently smaller than (ω · φ). Therefore, when the target value Vq ** is determined, a constant value when the load weight is an arbitrary reference value can be used as the magnitude Iq of the q-axis direction component of the current I. Also, when the magnitude Id of the d-axis direction component of the current I is zero, the applied voltage V d
Since the magnitude Vd of the axial component is given by the magnitude (ω · L · Iq) of the voltage due to the inductance L, the magnitude Iq of the q-axis component of the current I is defined as the magnitude of the d-axis component of the applied voltage V. A value calculated from the size Vd can also be used.

The magnitude of the q-axis direction component of the voltage command signal V * is derived by deriving a voltage phase advance angle for making the magnitude Vq * of the q-axis direction component of the voltage command signal V * follow the target value Vq **. If Vq * is controlled, regardless of the load weight,
The magnitude Id of the d-axis direction component of the current I can be zero.

In the above control device, as described above, the magnitude Id of the d-axis direction component of the current I flowing through the winding, that is, the magnitude Id of the current component that does not contribute to the generation of torque is always zero regardless of the load weight. It is possible to obtain high motor efficiency. Further, the voltage phase advance angle according to the load weight can be derived by a simple calculation process without using a complicated table like the conventional inverter device.

[0029]

According to the brushless motor controller of the present invention, high motor efficiency can be obtained.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be described below.
First, a specific description will be given based on three examples.First embodiment The overall configuration of the brushless motor control device of the present embodiment is
The conventional control device shown in FIG. 10 except for the PWM control circuit.
Identical to and deployed on the circumference of the brushless motor
3 position sensors (3) (3) (3) (3)
Position signals (Hu, Hv, Hw) are supplied to the PWM control circuit.
The PWM control circuit controls the inverter (6).
Has been.

FIG. 2A shows the waveforms of the voltages (Eu, Ev, Ew) induced by the interlinkage magnetic flux in the three-phase windings of the brushless motor, and each voltage waveform has one cycle of 360 degrees. Changes into a sine wave, and the three voltage waveforms are 12
It has a phase difference of 0 degree. Further, FIG. 3B shows three position signals (Hu, Hv,
Hw). Each position signal is a rectangular wave that switches to high and low with 360 degrees as one cycle, and the three position signals have a phase difference of 120 degrees with each other.

FIG. 1 shows the configuration of the PWM control circuit (1) of this embodiment. 3 obtained from the position sensor
The position signals (Hu, Hv, Hw) are calculated by the position calculation circuit (15).
And to the rotation speed detection circuit (14). In the rotation speed detection circuit (14), three position signals (Hu,
The rotation speed ω of the motor is detected based on (Hv, Hw),
The result is supplied to the phase advance angle deriving circuit (12a) and the position calculation circuit (15) which form the voltage command control circuit (12).
The position calculation circuit (15) has three position signals (Hu, Hv,
Hw) and the rotation speed ω based on the rotation angle θ of the motor.
Is calculated, and the calculated rotation angle θ is supplied to the voltage command signal generation circuit (12b) that constitutes the voltage command control circuit (12).

Rotational speed ω obtained from the rotational speed detection circuit (14)
Is supplied to the rotation speed control circuit (11), and in the circuit (11),
The voltage amplitude command Va is created based on the deviation of the motor speed from the target value ω *. The rotation speed control circuit (11) has a transfer function C (s), and the voltage amplitude command Va is calculated from the following Expression 2 using the transfer function C (s).

[0034]

[Formula 2] Va = C (s) · (ω * −ω)

Here, the transfer function C (s) is expressed, for example, by the following equation 3, and the voltage amplitude command Va is PI controlled.

[0036]

## EQU3 ## C (s) = Kp + Ki / s Kp, Ki: constant

The voltage amplitude command Va created as described above
Is supplied to the phase advance angle deriving circuit (12a). In the phase advance angle derivation circuit (12a), first, the phase advance angle ψo is calculated based on the rotation speed ω obtained from the rotation speed detection circuit (14). Here, when the load weight is constant, a constant relationship is established between the rotational speed ω of the motor and the phase advance angle ψ to be given to the voltage command signal Vu * described later, as shown in FIG.
The built-in memory of the phase advance angle deriving circuit (12a) stores a table showing the above relationship when the load weight has an arbitrary reference value, for example, a reference phase advance angle table as shown in FIG. Based on the reference phase advance angle table,
The phase advance angle ψo at the reference load weight is derived from the rotation speed ω. Then, the phase advance angle ψo is corrected using the following equation 4.

[0038]

[Equation 4] ψ = k · ψo k: correction factor

When the load weight increases, the motor rotation speed ω
Is decreased, and a larger voltage amplitude command Va is derived by the rotation speed control circuit (11). Further, as the load weight increases, it is necessary to further advance the phase of the voltage command signal Vu *. Therefore, the voltage amplitude command Va and the voltage command signal Vu *
Between the phase advance angle ψ which should be given to
A relationship is established in which the phase advance angle ψ increases as a increases. In this way, since a constant relationship is established between the voltage amplitude command Va and the phase advance angle ψ, the voltage amplitude command Va
A certain relationship is established between and the correction coefficient k.

FIG. 5 shows the relationship between the voltage amplitude command Va and the correction coefficient k. Between the voltage amplitude command Va and the correction coefficient k, as shown in the drawing, the correction coefficient at the reference load weight is shown. When k is 1, the correction coefficient k increases as the voltage amplitude command Va increases, while the voltage amplitude command V increases.
As a decreases, the correction coefficient k decreases. The above relationship is experimentally or theoretically obtained, and the internal memory of the phase advance angle deriving circuit (12a) stores a table representing the relationship, for example, a correction coefficient table as shown in FIG. Based on the correction coefficient table, the voltage amplitude command Va obtained from the rotation speed control circuit (11)
The correction coefficient k corresponding to the load weight is determined from the.

When the load weight is the same as the reference value, a value of 1 is determined as the correction coefficient k, and the phase advance angle ψo at the reference load weight is multiplied by the correction coefficient k of 1. When the load weight increases above the reference value, the voltage amplitude command Va increases and a correction coefficient k larger than 1 is determined, and the phase advance angle ψo at the reference load weight is multiplied by the correction coefficient k larger than 1. To be done. On the other hand, when the load weight is reduced below the reference value, the voltage amplitude command Va
Is reduced, a correction coefficient k smaller than 1 is determined, and the phase advance angle ψo at the reference load weight is multiplied by the correction coefficient k smaller than 1. Therefore, when the load weight is the same value as the reference value, the phase advance angle ψ having the same value as the phase advance angle ψo at the reference load weight is derived.
When the load weight increases above the reference value, a phase advance angle ψ larger than the phase advance angle ψo at the reference load weight is derived. On the other hand, when the load weight decreases, the phase advance angle ψ at the reference load weight increases. A phase advance angle ψ smaller than ψo will be derived. In this way, the phase advance angle ψo at the reference load weight is corrected to the phase advance angle ψ according to the load weight based on the voltage amplitude command Va.

The phase advance angle ψ obtained from the phase advance angle derivation circuit (12a) is supplied to the voltage command signal generation circuit (12b). The voltage amplitude command Va obtained from the rotation speed control circuit (11) as described above is supplied to the voltage command signal generation circuit (12b). In the voltage command signal generation circuit (12b), based on the voltage amplitude command Va, the rotation angle θ supplied from the position calculation circuit (15), and the phase advance angle ψ, the above formula 1
From this, the voltage command signal Vu * for the U phase of the brushless motor is calculated.

1 for the U-phase voltage command signal Vu *
By giving a phase difference of 20 ° and 240 °, a V phase voltage command signal Vv * and a W phase voltage command signal Vw * are created, and these three phase voltage command signals (Vu *, Vv *, V
w *) is supplied to the PWM signal generation circuit (13). PW
In the M signal generation circuit (13), as shown in FIG. 2C, the U-phase voltage command signal Vu * is compared with a predetermined carrier wave (triangular wave), and based on the comparison result, FIG. The U-phase drive signal (PWM signal) shown in is created. Similarly, the V-phase voltage command signal Vv * is compared with a predetermined carrier to create a V-phase drive signal, and the W-phase voltage command signal Vw * is compared with the predetermined carrier to obtain W. A phase drive signal is created.

The U-phase, V-phase, and W-phase PWM signals thus created are supplied to the inverter (6) shown in FIG. 10, and the inverter (6) is PWM-controlled. As a result,
The brushless motor (2) will be driven.

FIG. 7 shows the phases of the voltage V applied to the motor and the current I flowing through the winding. Same figure (a) (b)
(c) shows the applied voltage V and the current I when the rotational speed ω of the motor is the same, where the direction of the magnetic flux generated from the permanent magnet of the brushless motor is the d axis, and the direction orthogonal to the magnetic flux direction is the q axis. The phase of the applied voltage V and the current I when the load weight has the same value as the above reference value, and the same figure (b) shows the load weight from the above reference value. The phase of the applied voltage V and the current I when it also increases, FIG.
Indicates the phase of the applied voltage V and the current I when the load weight is reduced below the reference value.

When a voltage V is applied to the motor, a current I flows through the winding, and an induced voltage (ω · φ) due to the interlinkage magnetic flux φ, a voltage (ω · L · I) due to the inductance L of the winding, And a voltage (R · I) due to the resistance R of the winding is generated in the winding. When the load weight has the same value as the reference value, the phase advance angle ψo having the same value as the phase advance angle ψo at the reference load weight is given as described above, and as shown in FIG. Since the phase of the current I flowing in the phase coincides with the phase of the induced voltage (ω · φ) due to the interlinking magnetic flux φ, no current component in the d-axis direction that does not contribute to the generation of torque is not generated. Further, when the load weight increases above the reference value, a phase advance angle ψ larger than the phase advance angle ψo at the reference load weight is given as described above,
As shown in (b), the phase of the current I flowing through the winding matches the phase of the induced voltage (ω · φ) due to the interlinking magnetic flux φ, and no current component in the d-axis direction that does not contribute to torque generation is generated. .
Further, when the load weight is smaller than the reference value, a phase advance angle ψ smaller than the phase advance angle ψo in the reference load weight is given as described above, and as shown in FIG. The phase of the flowing current I is the induced voltage (ω
・ Φ), which does not contribute to the generation of torque.
No axial current component is generated.

In the brushless motor control apparatus according to the present embodiment, as described above, not only when the load weight is the same as the reference load weight, but also when the load weight is larger or smaller than the reference load weight, It is possible to prevent the generation of a current component that does not contribute to the generation of torque, which makes it possible to obtain high motor efficiency. Further, as shown in FIG. 4, the reference phase advance angle table used when deriving the phase advance angle ψ according to the load weight represents the relationship between the two parameters of the motor rotation speed ω and the phase advance angle ψo. It is a thing. Further, the correction coefficient table, as shown in FIG. 6, represents the relationship between the two parameters of the voltage amplitude command Va and the correction coefficient k. Therefore, these tables are simpler than the conventional tables showing the relationship between the three types of parameters. In this way, the phase advance angle ψo and the correction coefficient k at the reference load weight are derived from the simple reference phase advance angle table and the correction coefficient table, and based on the phase advance angle ψo and the correction coefficient k, the above number is calculated. From 4, the phase advance angle ψ according to the load weight is derived. Therefore, as compared with the conventional inverter device having a complicated table, the calculation process when deriving the phase advance angle ψ according to the load weight is simpler.

[0048]Second embodiment The phase advance angle derivation circuit (12a) of the first embodiment shown in FIG.
As described above, based on the voltage amplitude command Va, the reference negative
In contrast to correcting the phase advance angle in the load amount, the actual
The phase lead angle deriving circuit of the embodiment uses the voltage command for the U phase.
Based on the magnitude Vd * of the d-axis direction component of the signal V *,
The phase advance angle is corrected.

FIG. 8 shows the configuration of the PWM control circuit (7) of this embodiment. The three position signals (Hu, Hv, Hw) obtained from the position sensor are supplied to the position calculation circuit (75) and the rotation speed detection circuit (74). In the rotation speed detection circuit (74), three position signals (Hu, Hv,
The rotation speed ω of the motor is detected based on (Hw), and the result is supplied to the phase advance angle derivation circuit (72a) and the position calculation circuit (75) which form the voltage command control circuit (72). The position calculation circuit (75) calculates the rotation angle θ of the motor based on the three position signals (Hu, Hv, Hw) and the rotation speed ω, and the calculated rotation angle θ is calculated by the voltage command control circuit ( It is supplied to the voltage command signal generation circuit (72b) that composes 72).

Rotational speed ω obtained from the rotational speed detection circuit (74)
Is supplied to the rotation speed control circuit (71), and in the circuit (71),
Based on the deviation of the motor rotation speed from the target value ω *, the voltage amplitude command Va is created from the expressions 2 and 3. The voltage amplitude command Va is supplied to the voltage command signal generation circuit (72b),
In the circuit (72b), the voltage amplitude command Va obtained from the rotation speed control circuit (71), the rotation angle θ obtained from the position calculation circuit (75), and the phase advance angle derivation circuit (72a) described later are obtained. The voltage command signal Vu * for the U phase of the brushless motor is calculated from Equation 1 based on the phase advance angle ψ. Then, a voltage command signal Vv * and a voltage command signal Vw * are created based on this voltage command signal Vu *, and these three-phase voltage command signals (Vu *, Vv *, Vw).
*) Is supplied to the PWM signal generation circuit (73), and the U phase,
PWM signals for the V phase and the W phase are created.

The voltage amplitude command Va obtained from the rotation speed control circuit (71) is supplied to the voltage component calculation circuit (72c). In the voltage component calculation circuit (72c), the voltage amplitude command Va
And the phase advance angle ψ derived in the previous calculation cycle in the phase advance angle deriving circuit (72a) described later, from the following equation 5, the d-axis direction component of the voltage command signal V * for the U phase Vd * is calculated.

[0052]

## EQU00005 ## Vd * =-Va.sin .psi.

The magnitude Vd * of the d-axis direction component thus calculated is supplied to the phase advance angle deriving circuit (72a). In the phase advance angle deriving circuit (72a), first, as in the first embodiment, based on the reference phase advance angle table shown in FIG. 4, the reference value is obtained from the rotation speed ω obtained from the rotation speed detection circuit (74). The phase advance angle ψo at the load weight is calculated, and then the phase advance angle ψo is corrected by using the above equation 4.

When the load weight increases, in order to increase the magnitude Iq of the q-axis direction component, which contributes to the generation of torque, among the components of the current I flowing through the winding, the voltage command signal V * d
The magnitude Vd * of the axial component increases. Further, as described above, it is necessary to further advance the phase of the voltage command signal V * as the load weight increases. Therefore, the voltage command signal V
Between the magnitude Vd * of the d-axis direction component of * and the phase advance angle ψ to be given to the voltage command signal V *, the phase advance angle ψ increases as the magnitude Vd * of the d-axis direction component increases. The relationship is established. As described above, since a certain relationship is established between the magnitude Vd * of the d-axis direction component of the voltage command signal V * and the phase advance angle ψ, it is equal to the d-axis direction component Vd * of the voltage command signal V *. A certain relationship is established with the correction coefficient k of the above equation 4. Therefore, the phase advance angle derivation circuit (7
The internal memory of 2a) has a table showing such a relation,
That is, a correction coefficient table similar to the table shown in FIG. 6 is stored, and based on the correction coefficient table, the correction coefficient corresponding to the load weight from the magnitude Vd * of the d-axis direction component of the voltage command signal V *. k is determined.

Using the correction coefficient k thus determined and the phase advance angle ψo at the reference load weight, the phase advance angle ψ corresponding to the load weight is calculated from the above equation (4). This phase advance angle ψ is the voltage command signal generation circuit (72b)
The voltage command signal Vu * is calculated in the circuit (72b) based on the voltage amplitude command Va, the rotation angle θ, and the phase advance angle ψ, as described above.

According to the controller of the brushless motor of the present embodiment, the phase of the current flowing through the winding is matched with the phase of the induced voltage generated in the winding so that the current component that does not contribute to the torque generation is generated. It is possible to prevent this, and thereby high motor efficiency can be obtained.

Further, in the control device of this embodiment, when deriving the phase advance angle ψ according to the load weight, the same reference phase advance angle table and voltage command signal V as in the first embodiment are used.
A correction coefficient table representing the relationship between the magnitude Vd of the d-axis direction component of * and the correction coefficient k is used. The correction coefficient table represents the relationship between two types of parameters, and is simpler than the conventional table that represents the relationship between three types of parameters. In this way, the phase advance angle ψo and the correction coefficient k at the reference load weight are derived from the simple reference phase advance angle table and the correction coefficient table, and based on the phase advance angle ψo and the correction coefficient k, the above number is calculated. From 4, the phase advance angle ψ according to the load weight is derived.
Therefore, as compared with the conventional inverter device having a complicated table, the calculation process when deriving the phase advance angle ψ according to the load weight is simpler.

[0058]Third embodiment The phase lead angle deriving circuit of the present embodiment uses the voltage for the U phase.
The magnitude Vq * of the q-axis direction component of the command signal V * and the target value
Phase advance according to the load weight based on the deviation from Vq **
The angle ψ is derived.

FIG. 9 shows the configuration of the PWM control circuit (8) of this embodiment. The three position signals (Hu, Hv, Hw) obtained from the position sensor are supplied to the position calculation circuit (85) and the rotation speed detection circuit (84). The rotation speed detection circuit (84) has three position signals (Hu, Hv,
The rotation speed ω of the motor is detected based on (Hw), and the result is supplied to the position calculation circuit (85). Position calculation circuit (85)
Then, the rotation angle θ of the motor is calculated based on the three position signals (Hu, Hv, Hw) and the rotation speed ω, and the calculated rotation angle θ is the voltage forming the voltage command control circuit (82). It is supplied to the command signal generation circuit (82c).

Rotational speed ω obtained from the rotational speed detection circuit (84)
Is supplied to the rotation speed control circuit (81), and in the circuit (81),
Based on the deviation of the motor rotation speed from the target value ω *, the voltage amplitude command Va is created from the expressions 2 and 3. The voltage amplitude command Va is supplied to the voltage command signal generation circuit (82c),
In the circuit (82c), the voltage amplitude command Va obtained from the rotation speed control circuit (81), the rotation angle θ obtained from the position calculation circuit (85), and the phase advance angle derivation circuit (82b) described later are obtained. The voltage command signal Vu * for the U phase of the brushless motor is calculated from Equation 1 based on the phase advance angle ψ. Then, a voltage command signal Vv * and a voltage command signal Vw * are created based on this voltage command signal Vu *, and these three-phase voltage command signals (Vu *, Vv *, Vw).
*) Is supplied to the PWM signal generation circuit (83), and the U phase,
PWM signals for the V phase and the W phase are created.

The voltage amplitude command Va obtained from the rotation speed control circuit (81) is supplied to the voltage component calculation circuit (82d). In the voltage component calculation circuit (82d), the voltage amplitude command Va
And the phase advance angle ψ derived in the previous calculation cycle in the phase advance angle deriving circuit (82b) described later, from the following equation 6, the q-axis direction component of the voltage command signal V * for the U phase Vq * is calculated.

[0062]

[Equation 6] Vq * = Va · cosψ

The magnitude Vq * of the q-axis direction component calculated in this manner is supplied to the subtraction circuit (82a) which constitutes the voltage command control circuit (82), and the circuit (82a) commands the voltage command. Signal V
The deviation from the target value Vq ** of the q-axis direction component of * is calculated. The calculated deviation is supplied to the phase advance angle deriving circuit (82b), and the phase advance angle deriving circuit (82b) derives the phase advance angle ψ based on the deviation. Phase advance angle derivation circuit (8
2b) has a transfer function Cph (s), and the phase advance angle ψ is calculated from the following Expression 7 using the transfer function Cph (s).

[0064]

[Formula 7] ψ = Cph (s) · (Vq **-Vq *)

Here, the transfer function Cph (s) is represented by the following expression 8, for example, and the phase advance angle ψ is PI controlled.

[0066]

[Equation 8] Cph (s) = Kp + Ki / s Kp, Ki: constant

The magnitude Vq of the q-axis direction component of the voltage V applied to the motor is Iq, the magnitude of the q-axis direction component of the current I flowing through the winding, Id, the magnitude of the d-axis direction component of the winding. Is represented by L, the winding resistance is R, and the number of interlinkage magnetic fluxes of the winding is φ.

[0068]

[Equation 9] Vq = ω ・ L ・ Id + R ・ Iq + ω ・ φ

The q-axis direction component of the current I flowing through the winding is a current component that contributes to torque generation, and the d-axis direction component is a current component that does not contribute to torque generation. Therefore, the magnitude (R · Iq) of the q-axis direction component of the applied voltage V when the magnitude Id of the d-axis direction component of the current I flowing in the winding is zero.
+ Ω · φ) is set as the target value Vq ** of the q-axis direction component of the voltage command signal V *. Here, the magnitude Iq of the q-axis direction component of the current I fluctuates according to the fluctuation of the load weight, but the fluctuation is only slight, and the magnitude of the voltage (R.Iq ) Is a value sufficiently smaller than the magnitude (ω · φ) of the induced voltage due to the interlinkage magnetic flux φ. Therefore, regarding the magnitude of the q-axis direction component of the current I, a value when the load weight is an arbitrary reference value is experimentally or theoretically obtained in advance, and the value is calculated as the magnitude of the q-axis direction component of the current I. I
It can be used as q. Further, the magnitude Vd of the d-axis direction component of the voltage V applied to the motor is expressed by the following formula 10
And the magnitude Iq of the q-axis component of the current I
For this, it is also possible to use a value calculated from the following Equation 10 with the magnitude Id of the d-axis direction component being zero.

[0070]

[Formula 10] Vd = ω · L · Iq + R · Id

In the phase advance angle deriving circuit (82b), the magnitude Vq * of the q-axis direction component of the voltage command signal V * is set to the target value V
A phase advance angle ψ for tracking q ** is derived.
In this manner, by controlling the magnitude Vq * of the q-axis direction component of the voltage command signal V *, the magnitude Id of the d-axis direction component of the current I flowing through the winding is always zero regardless of the load weight. You can do it.

According to the brushless motor control apparatus of the present embodiment, as described above, the magnitude Id of the d-axis direction component of the current I flowing through the winding, that is, the torque is always generated regardless of the load weight. The magnitude of the current component that does not occur can be set to zero, whereby high motor efficiency can be obtained.

Further, in the control device of this embodiment, the phase advance angle ψ corresponding to the load weight is derived by using the above equations 6 to 8. Therefore, as compared with the conventional inverter device having a complicated table, the calculation process when deriving the phase advance angle according to the load weight is simpler.

The configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope described in the claims. For example, in the first and second embodiments, based on the reference phase advance angle table shown in FIG.
Although the configuration for deriving the phase advance angle ψo at the reference load weight is adopted, instead of this, the phase advance angle ψo is calculated based on a functional expression in which the rotation speed ω of the brushless motor is a variable.
It is also possible to adopt a configuration for calculating

In the first embodiment, the correction coefficient k is derived based on the correction coefficient table shown in FIG. 6, and in the second embodiment, the voltage command signal V * d
Although the correction coefficient k is derived based on the correction coefficient table representing the relationship between the magnitude Vd * of the axial component and the correction coefficient, the voltage amplitude command Va
Alternatively, the magnitude Vd * of the component in the d-axis direction of the voltage command signal V *
It is also possible to adopt a configuration in which the correction coefficient k is calculated based on a functional expression in which is a variable.

Furthermore, in the second embodiment, the correction coefficient k is derived from the magnitude Vd * of the d-axis direction component of the voltage command signal V *, but instead of this, the q-axis direction is used. It is also possible to employ a configuration in which the correction coefficient k is calculated from the component magnitude Vq *. Further, a value (Va / ω) obtained by dividing the voltage amplitude command Va by the rotation speed ω of the motor, the voltage amplitude command Va and the voltage amplitude command V at the reference load weight.
A value (Va / Vao) obtained by dividing ao, a value (Vd * / ω) obtained by dividing the magnitude Vd * of the d-axis direction component of the voltage command signal V * by the rotation speed ω of the motor, q A value obtained by dividing the magnitude Vq * of the axial component by the motor speed ω
It is also possible to employ a configuration in which the correction coefficient k is calculated from (Vq * / ω) or the magnitude Iq of the q-axis direction component of the current flowing through the winding.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a PWM control circuit that constitutes a control device of a first embodiment.

FIG. 2 is a waveform diagram of various signals created in the PWM control circuit.

FIG. 3 is a graph showing the relationship between the rotation speed of the motor and the phase advance angle.

FIG. 4 is a reference phase advance angle table representing the above relationship.

FIG. 5 is a graph showing a relationship between a voltage amplitude command and a correction coefficient.

FIG. 6 is a correction coefficient table showing the above relationship.

FIG. 7 is a diagram showing a voltage applied to a motor and a phase of a current flowing through a winding by a control device according to the present invention.

FIG. 8 is a block diagram showing the configuration of a PWM control circuit that constitutes the control device of the second embodiment.

FIG. 9 is a block diagram showing the configuration of a PWM control circuit that constitutes the control device of the third embodiment.

FIG. 10 is a block diagram showing an overall configuration of a brushless motor control device.

FIG. 11 is a block diagram showing a configuration of a PWM control circuit that constitutes a conventional control device.

FIG. 12 is a diagram showing phases of a voltage applied to a motor and a current flowing through a winding by a conventional control device.

[Explanation of symbols]

(1) PWM control circuit (2) Brushless motor (3) Position sensor (4) Commercial power supply (5) Rectifier circuit (6) Inverter (11) Speed control circuit (12) Voltage command control circuit (12a) Phase lead angle derivation circuit (12b) Voltage command signal generation circuit (13) PWM signal generation circuit (14) Rotation speed detection circuit (15) Position calculation circuit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H560 AA10 BB04 BB12 DA02 DA19                       DB02 EB01 SS07 XA04 XA05                       XA12 XA13 XA15

Claims (7)

[Claims] 1. A controller for a brushless motor comprising an inverter for supplying AC power to a brushless motor and a PWM control circuit for controlling the inverter, wherein the PWM control circuit detects a rotation speed of the brushless motor. Speed detection means, angle detection means for detecting the rotation angle of the brushless motor, voltage command based on a function representing the change of the voltage command signal with the rotation angle of the brushless motor, the voltage phase advance angle and the voltage amplitude command value as variables And a signal processing means for generating a PWM signal on the basis of the generated voltage command signal and supplying the PWM signal to an inverter, wherein the arithmetic processing means is a rotation of a brushless motor. A phase advance angle relationship storage unit that stores a relationship between a speed and a voltage phase advance angle; and the phase advance angle relationship case. In accordance with the relationship stored in the storing means, the phase advance angle deriving means for deriving the voltage phase advance angle from the detected rotation speed, and the voltage amplitude command value or a value corresponding to the voltage amplitude command value A correction processing unit that corrects the derived voltage phase advance angle, and a voltage command signal from the detected rotation angle and the correction phase advance angle and the voltage amplitude command value obtained from the correction processing unit based on the function. And a signal producing means for producing the controller. 2. The calculation processing means includes a coefficient relation storage means for storing a relationship between the voltage amplitude command value or a value corresponding to the voltage amplitude command value and a correction coefficient used for correcting the voltage phase advance angle. The correction processing means derives a correction coefficient from the voltage amplitude command value or a value corresponding to the voltage amplitude command value according to the relationship stored in the coefficient relationship storage means, and the derived voltage phase advance angle. 2. The correction phase advance angle is calculated by performing an operation using the correction coefficient on.
The control device according to 1. 3. The control device according to claim 2, wherein the correction processing means calculates a correction phase advance angle by multiplying the derived voltage phase advance angle by the derived correction coefficient. 4. The PWM control circuit comprises speed control means for deriving a voltage amplitude command value based on a deviation between the detected rotation speed and a target rotation speed, and the correction processing means of the arithmetic processing means comprises: 4. The control device according to claim 1, wherein the voltage phase advance angle is corrected based on the voltage amplitude command value derived by the speed control means. 5. The brushless motor among the signal components of the voltage command signal created by the signal creating means based on the voltage amplitude command value and the corrected phase advance angle calculated by the correction processing means. Comprising a component calculating means for calculating the magnitude of the component in the direction of the magnetic flux generated from the magnet constituting the magnet, or the magnitude of the component in the direction orthogonal to the direction of the magnetic flux, and the correction processing means calculates by the component calculating means. 4. The control device according to claim 1, wherein the voltage phase advance angle is corrected based on the magnitude of the generated magnetic flux direction component or the magnitude of the orthogonal direction component. 6. A brushless motor control device comprising an inverter for supplying AC power to a brushless motor and a PWM control circuit for controlling the inverter, wherein the PWM control circuit detects a rotation speed of the brushless motor. Speed detection means, angle detection means for detecting the rotation angle of the brushless motor, voltage command based on a function representing the change of the voltage command signal with the rotation angle of the brushless motor, the voltage phase advance angle and the voltage amplitude command value as variables And a signal processing unit that creates a PWM signal based on the created voltage command signal and supplies the PWM signal to an inverter. The magnitude of the signal component in the direction orthogonal to the direction of the magnetic flux generated from the magnets that make up the brushless motor And a phase advance angle deriving means for deriving a voltage phase advance angle on the basis of a deviation between the target value of the orthogonal direction component, and the detected rotation angle and the derived voltage phase advance angle based on the function. And a signal creating means for creating a voltage command signal from the voltage amplitude command value. 7. The component calculating means for calculating the magnitude of the orthogonal direction component of the voltage command signal based on the voltage amplitude command value and the voltage phase advance angle derived by the phase advance angle deriving means. The control device according to claim 6, further comprising: