JP2002320400A - Synchronous motor control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stable acceleration by making it difficult that a terminal voltage of a synchronous motor is saturated. SOLUTION: An equivalent magnetic field control of motor 4 is realized by setting a vertical axis current Id1 to the proportional relationship of a horizontal axis current Iq in the speed from 0 to basic rotating speed Nbase , setting another vertical axis current Id0 to the function of speed using the proportional constants Kd2 , Kd3 in the speed from the basic rotating speed Nbase to the maximum rotating speed Ntop , and defining the vertical current Id by adding the vertical axis current Id1 and the vertical axis current Id0 . Moreover, during acceleration of motor 4, the equivalent magnetic field is increased or decreased in proportion to the rotating angle N of the motor 4 using Kd3 as a variable. Consequently, the vertical axis current Id0 for suppressing a terminal voltage VM remarkably increases to result in making it difficult that the terminal voltage VM of motor 4 is saturated. Accordingly, stable acceleration can e realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor, and more particularly to a synchronous motor control method using a permanent magnet as a field, and more particularly to a synchronous motor control method requiring a wide constant output range.

[0002]

2. Description of the Related Art In a method of controlling a permanent magnet synchronous motor, which is a kind of a synchronous motor requiring a constant output ratio of 1: n, disclosed in Japanese Patent Application Laid-Open No. H10-14299, the maximum rotational speed of the synchronous motor is determined. N _top , base rotation speed N _base = N
_top / n, and the rotational speed N of the synchronous motor is expressed as (A) 0
<N ≦ N _base range and (B) N _base <N ≦ N _top 2
Vector control is performed in two control ranges. Hereinafter, this control method will be specifically described.

First, in the control range of (A), the required output is
Torque command T necessary to secure _ref(%)
-Axis current command I flowing_q, Q axis of torque command proportional component
Current command I_q1, D-axis current command I_d, The torque command proportional component
d-axis current command I_d1The relationship of I_q= I_q1= I_qmax× (T
_ref/ 100) [I_qmaxIs the q-axis current at 100% rating
Command I_q] (1), I_d= K_d1× I_q[However, K_d1Is
Proportional constant] (2) is performed and vector control is performed.

Further, in the control range of (B), a q-axis current command I _q1 and a q-axis current command I _d1 for securing required output are provided.
In addition to the relationship, the d-axis current command I _d0 for suppressing the synchronous motor terminal voltage is given by I _d0 = K _d2 × (N−N _base ) /
(N _top -N _base ) [where K _d2 is a proportional constant] ...
(3), I _d = I _d0 + I _d1 (4), and vector control is performed.

FIG. 5 is a block diagram of a control device for executing the control method described above. As shown in FIG. 5, 1 is a vector calculator, 2 is a PWM generator, 3 is an inverter power unit, 4 is a permanent magnet synchronous motor (motor), 5 is a position detector (PG), 6 is a speed calculator, 7 is a three-phase dq converter, 8 is an I _d1 operator, 9 is an I _d0 operator, 10 is a current detector, 11 is a speed regulator, 12 is an I _q1 converter, 14, 1
5 and 17 are subtractors, and 16 is an adder.

The speed calculator 6 calculates the rotational speed of the motor 4 from the position of the motor 4 obtained from the PG 5, that is, the speed feedback signal N. Difference e between speed command N ^* obtained by subtractor 14 and speed feedback signal N
Is input to the speed regulator 11. The speed regulator 11 performs proportional-integral (PI) control based on the speed deviation e and outputs a torque command _Tref . The I _q1 converter 12 converts the torque command T _ref into the q-axis current command I _q by using the above equation (2).
And output.

When the q-axis current command _Iq is input to the _Id1 calculator 8 as a torque command proportional component, a d-axis current command _Id1 is generated by multiplying the q-axis current command _Iq by a proportional coefficient _Kd1. Is done. The subtractor 15 calculates the difference between the q-axis current command _Iq and the q-axis current feedback signal _Iqfb obtained by inputting the motor current detected by the current detector 10 to the three-phase dq converter 7. Then, it is input to the vector operation unit 1.

On the other hand, the d-axis current command I _d includes a d-axis current command I _d0 and a d-axis current command I _{d1 of a} speed proportional component obtained by inputting the speed feedback signal N to the I _d0 calculator 9. Are created by adding in the adder 16. The subtractor 17 calculates the d-axis current command I _d to d
The shaft current feedback signal I _dfb is subtracted and input to the vector operation unit 1.

The vector operation unit 1 outputs a voltage command V ^* of the motor 4 and a phase control angle command θ ^* . PWM generator 2
Is PWM based on the voltage command V ^* and the phase control angle command θ ^*.
A pulse is generated to drive the inverter power unit 3 to control the speed of the motor 4.

FIG. 6 is an equivalent circuit diagram of the motor 4, that is, the synchronous motor. When the number of poles of the motor 4 and P _ole,
The angular velocity ω of the motor 4 is represented by the following equation (5).

[0011] _{ω = 2π × P ole / 120} × N ... (5) of the motor 4 primary resistance r ≒ 0, the q-axis voltage V _q, when the d-axis voltage and V _d, the terminal voltage V _M of the motor 4 is , And is represented by the following equation (6).

V _M ² = V _q ² + V _d ² (6) Further, the induced voltage E of the motor 4 is expressed by the following equation (7).

E = K _E × N [K _E is the induced voltage coefficient of the magnet] (7) The q-axis voltage V _q of the motor 4 is represented by the following equation (8).

[0014] _{V q = E-I d ×} L d × ω = N (b-aN) [ provided _{that, a = L d × 2π ×} P ole / 120 × K d2 / N top -N bas e, b = K _{E + L d × 2π × P} ole / 120 (K d2 × N base / (N top -N base) - K d1 × I qmax × (T ref / 100)), d -axis inductance L _d is the motor 4] ... (8) d-axis voltage V _d of the motor 4 is represented as the following equation (9).

[0015] _{V d = -I q L q ω} = -cN [ _{However, c = L q × 2π ×} P ole / 120 × I qmax × (T ref / 100)), L q is q-axis inductance of the motor 4 ] (9) From the equations (6), (8) and (9), the terminal voltage V of the motor 4 is obtained.
_M is represented by the following equation (10).

[0016] _{V M = N × √ ((} b-aN) 2 + c 2) ... (10) 5, the rotational speed of the motor 4, i.e. a speed feedback signal N, and the terminal voltage V _M, q-axis voltage V _q, is a graph showing the relationship between the d-axis voltage V _d. As shown in FIG.
The q-axis voltage _Vq becomes maximum at N = b / 2a as shown in the equation (6), and the d-axis voltage _Vd becomes N as shown in the equation (8).
= Maximum at N _top, the terminal voltage V _M, as shown in equation (10), the maximum N = b / a.

As described above, in the control method of the permanent magnet synchronous motor, which is a kind of the synchronous motor requiring a constant output ratio of 1: n, the terminal voltage becomes N = b /
There is a problem that the maximum value is reached at the point a and saturation occurs, the control becomes impossible, and the acceleration time becomes long.

[0018]

As described above,
In a conventional control method of a permanent magnet synchronous motor, which is a kind of a synchronous motor requiring a constant output ratio of 1: n, the terminal voltage of the motor becomes maximum between the maximum rotation speed and the base rotation speed. During the acceleration, there is a problem that the terminal voltage is saturated, the control becomes impossible, and the acceleration time becomes longer.

According to the present invention, the terminal voltage is less likely to be saturated,
An object of the present invention is to provide a synchronous motor control method capable of realizing stable acceleration.

[0020]

In order to solve the above-mentioned problem, in the synchronous motor control method of the present invention, the maximum rotational speed of the synchronous motor requiring a constant output ratio of 1: n is set to N _top , and the base speed is set to N _top. represents the rotation speed and _{n b ase = n top / n} , the rotational speed n of the synchronous motor, and a range of (a) 0 <n ≦ n base,
(B) The control range is divided into two control ranges of N _base <N ≦ N _{top. In} the control range of (A), the torque control T _ref (%) necessary to secure the required output is performed. The relationship between the flowing q-axis current command I _q , q-axis current command I _q1 , d-axis current command I _d , and d-axis current command I _d1 of the torque command proportional component is represented by I _q = I
_q1 = _Iqmax × ( _Tref / 100) [ _Iqmax is 100%
Q-axis current command at rated time I _q ], I _d = I _d1 = K _d1 × I
_q [where K _d1 is a proportional constant], and in the control range of (B), the q-axis current commands I _q and I _q1 and the d-axis current command I
In addition to the relationship of _d1, the d-axis current command I _d0 in order to suppress the synchronous motor terminal voltage _{V M, I d0 = K d2} × K d3 × (N-
N _base ) / (N _top −N _base ) [where K _d2 and K _{d 3} are proportional constants], and the d-axis current command I _d is given by I _d = I _d0 + I
In the synchronous motor control method for performing vector control stipulates that _d1, During acceleration of the synchronous motor, the K _d3 and one or more variables, and wherein the increase or decrease in proportion to the rotation angle N.

According to the synchronous motor control method of the present invention, during acceleration of the synchronous motor, K _d3 is defined as one or more variables.
It is increased or decreased in proportion to the rotation angle N of the synchronous motor. By doing so, the d-axis current command for suppressing the terminal voltage of the synchronous motor is made proportional to the square of the rotational speed of the synchronous motor, and d
Increase the shaft current command. Therefore, in the synchronous motor control method of the present invention, the terminal voltage of the synchronous motor is less likely to be saturated during acceleration, and stable acceleration can be realized.

[0022]

Next, a synchronous motor control method according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a control device that implements the synchronous motor control method according to the present embodiment. As shown in FIG. 1, the control device, I instead of I _d0 converter 9 _d0
The control device shown in FIG. 5 is different from the control device shown in FIG. 5 in that a converter 19 is provided and an acceleration determiner 13 is newly provided.

The I _d0 converter 19 sets I _d0 to 0 in the control range of (A) described above, and calculates and outputs I _d0 by the following equation (11) in the control range of (B).

I _d0 = K _d2 × K _d3 × (N−N _base ) / (N _top −N _base ) [where K _d2 is a proportionality constant, and K _d3 is one or more variables during motor 4 acceleration. Yes, otherwise, proportional constant] (11) The acceleration determiner 13 calculates the RUN signal input when the inverter power unit 3 is driven, the current detected by the current detector 10, and the speed calculation. The speed feedback signal N output from the device 6 is input. The acceleration determiner 13 calculates R
The UN signal is active, a torque is calculated from the current detected by the current detector 10, and it is determined whether or not the motor 4 is accelerating based on the fluctuation of the torque. When it is determined that the motor 4 is accelerating, the acceleration determiner 13 inputs the speed feedback signal N, determines K _d3 , and sets it to the I _d0 calculator 19. K _d3 is the motor 4
During acceleration, the value is proportional to the speed feedback signal N.

The synchronous motor control method of the present embodiment will be summarized. In the synchronous motor control method of the present embodiment, similarly to the conventional synchronous motor control method, the maximum rotational speed of the synchronous motor is represented by _Ntop , and the base rotational speed is represented by _Nbase = _Ntop / n. N, (A) 0 <N ≦ N
Vector control is performed by dividing the control range into a _base range and (B) N _base <N ≦ N _top control ranges.

First, in the control range of (A), the required output is
Torque command T necessary to secure _ref(%)
-Axis current command I flowing_q, Q axis of torque command proportional component
Current command I_q1, D-axis current command I_d, Torque command proportional component
D-axis current command I_d1As shown in the above equation (2).
Then, vector control is performed.

Further, in the control range of (B), the aforementioned q
In addition to the relationship between the shaft current command I _q1 and the d-axis current command I _d1 , a d-axis current command I for suppressing the synchronous motor terminal voltage V _M.
The _d0, and the above equation _{(11), I d = I} d0 + I d1 ... (1
Vector control is performed by defining as in 2).

The q-axis voltage V _q of the motor 4, the following equation (1
It is expressed as 3).

[0029] _{V q = E-I d ×} L d × ω = N (b'-a'N) [ _{However, a '= L d × 2π} × P ole / 120 × K d2 × K d3 / N to p −N _base , b ′ = K _E + L _d × 2π × _Pole / 120 (K _d2 × N _base / (N _top −N _base ) −K _d1 × I _qmax × (T _ref / 100)), and L _d is d-axis inductance] ... (13) d-axis voltage V _d of the motor 4 of the motor 4 is represented as the above formula (9).

[0030] Equation (6), (9) and (13), the terminal voltage V _M of the motor 4 is given by the following equation (14).

[0031] _{V M = N × √ ((} b'-a'N) 2 + c 2) ... (14) 2, during acceleration of the motor 4 when using a synchronous motor control device of this embodiment, Rotation speed N of motor 4
When is a graph showing the d-axis voltage V _d, q-axis voltage V _q, the state of variation of the terminal voltage V _M. As shown in FIG. 2, the q-axis voltage V _q becomes maximum at N = b ′ / 2a ′ as shown in equation (13), and the d-axis voltage V _d becomes N = b as shown in equation (9).
The voltage becomes maximum at N _top and the terminal voltage V _M becomes maximum at N = b ′ / a ′ as shown in Expression (14). As aforementioned,
In the synchronous motor control method of the present embodiment, K _d3 (K _d3 is one or more variables)
Is increased or decreased in proportion to the rotation angle N of.

[0032] In the synchronous motor control method of this embodiment, compared with the conventional synchronous motor control method, the value of also the d-axis voltage V _d in the rotational speed N of the motor 4 throat is the same, the q-axis voltage V _q The maximum rotation speed b '/ 2a' of the motor 4
Is smaller than b / 2a and the terminal voltage V _M
Is the maximum value of the rotation speed b '/ a' of the motor 4 is also b / a
Smaller than. Accordingly, the synchronous motor control method of the present embodiment, the maximum value of the terminal voltage V _M is smaller than the maximum value of the terminal voltage V _M of the conventional synchronous motor control method.

FIG. 3 shows the output P, rotation speed N, d-axis current commands I _d0 , I _d1 , and q-axis current commands of the motor 4 during acceleration of the motor 4 when the synchronous motor control method of this embodiment is used. I _q, which is a graph showing how the terminal voltage V _M. FIG.
As shown in, the d-axis current command I _d0 in acceleration of the motor 4 in the synchronous motor control method of the present embodiment has a value greater than the d-axis current command I _d0 in the conventional synchronous motor control method, the The increase is proportional to the square of the rotation speed N. The d-axis current command I _d0 suppresses component terminal voltage V _M of the motor 4, that is, field-weakening磁量. Therefore, as shown in FIG. 3, the terminal voltage V _M of the motor 4 is lower than the terminal voltage V _M of the motor 4 in the conventional synchronous motor control method. Therefore, the synchronous motor control method of the present embodiment, and less likely to saturate the terminal voltage V _M of the motor 4 during acceleration, it is possible to achieve a stable acceleration.

Further, the proportional constant K_d1, K_d2Is a negative number (-)
And the motor 4 to be controlled is connected to a direct-axis (d-axis)
Cactance L_dIs the horizontal axis (q axis) inductance L_qthan
Small L_q> L_dPermanent magnet synchronous motor with saliency
Machine. FIG. 4 shows an example.
is there. As shown in the figure, a permanent magnet exists on the d-axis,
The magnetic flux due to the armature reaction from the theta side is difficult to pass,
Therefore, the d-axis direction inductance L_dIs small. Conversely, this
In the q-axis direction orthogonal to this, the armature reaction magnetic flux is
Easy to pass because of core core (rotor core), q-axis direction
Inductance L_qBecomes larger and L_q> L_dRelationship poke
It has a pole shape. (In contrast, L_q= L_dIs cylindrical
Say). Then, on the orthogonal dq coordinate axes, the magnetic flux
When the vector direction is taken in the plus (+) direction, this magnetic
I in the direction to weaken the stone flux, that is, in the minus (-) direction_d
Current (-I_d). For this, a proportional constant
Number K _d1, K_d2Is controlled to a negative number (-), the current vector
Is the leading phase and the induced voltage vector of the motor 4
And the induced voltage of the motor 4 is weakened (suppressed),
Furthermore, reluctance torque is superimposed on magnet torque due to saliency.
Because it is folded, the constant output range of the motor can be widened.
Wear. In addition, when the magnet shown in FIG.
In this case, the synchronous motor is a
The axis and q axis are switched (d axis → q axis, q axis → d axis
change to). And the proportional constant K_d1, K_d2To a positive number (+)
And + I_dIs controlled to flow. Therefore, the current base
The vector has a lag phase with respect to the d-axis magnetic flux vector,
Reluctance torque is generated. In addition, the control of the present invention
By using the equation, a wide range of constant output characteristics can also be obtained.
You.

[0035]

As described above, in the synchronous motor control method of the present invention, _{Kd3 is set} to one or more variables during acceleration of the synchronous motor, and is increased or decreased in proportion to the rotation angle N. By doing so, the d-axis current command for suppressing the terminal voltage of the synchronous motor is made proportional to the square of the rotation speed of the synchronous motor, and the d-axis current command is increased. Therefore, in the synchronous motor control method of the present invention, the terminal voltage of the synchronous motor is less likely to be saturated during acceleration, and stable acceleration can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a control device for executing a synchronous motor control method according to an embodiment of the present invention.

FIG. 2 is a graph showing the rotation speed of the motor, and changes in d-axis voltage, q-axis voltage, and terminal voltage when the motor is accelerated when the synchronous motor control method according to the embodiment of the present invention is executed. is there.

FIG. 3 is a graph showing a state of a motor output, a rotation speed, a d-axis current command, a q-axis current command, and a terminal voltage during motor acceleration when the synchronous motor control method according to one embodiment of the present invention is used. It is.

FIG. 4 is a diagram showing a structure of a permanent magnet synchronous motor.

FIG. 5 is a block diagram of a control device for executing a conventional synchronous motor control method.

FIG. 6 is an equivalent circuit diagram of the synchronous motor.

FIG. 7 is a graph showing a relationship among a motor rotation speed, a terminal voltage, a q-axis voltage, and a d-axis voltage in a conventional synchronous motor control method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vector calculation part 2 PWM generation part 3 Inverter power part 4 Synchronous motor (motor) 5 Position detector (PG) 6 Speed calculator 7 Three-phase dq converter 8 I _d1 converter 9, 19 I _d0 converter 10 Current detector 11 Speed adjuster 12 I _q1 converter 13 Acceleration determiner 14, 15, 17 Subtractor 16 Adder

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Gosho 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu-shi, Fukuoka F-term (reference) 5H560 BB04 BB17 DA07 DB20 DC12 EB01 UA02 XA02 XA04 XA12 XA13 XB07 5H576 BB09 DD05 EE01 EE02 EE11 FF02 GG02 GG04 HA02 HB01 JJ25 LL01 LL22 LL41

Claims (2)

[Claims] 1. The maximum rotation speed of a synchronous motor requiring a constant output ratio of 1: n is defined as _Ntop , and the base rotation speed is defined as _Nbase.
= N _top / n, and the rotational speed N of the synchronous motor is
(A) the range of 0 <N ≦ N _base , and (B) the N _base <N ≦ N
_In the control range of (A), the q-axis current commands _Iq and q flowing according to the torque command _Tref (%) necessary to secure the required output are divided into two control ranges, _ie, the _top range. The relationship between the axis current command I _q1 , the d-axis current command I _d , and the d-axis current command I _d1 of the torque command proportional component is expressed as I _q = I _q1 = I _qmax × (T _ref / 100) [I _qmax is 1
Q-axis current command at the time of 00% rating I _q ], I _d = I _d1 = K _d1 ×
I _q [where K _d1 is a proportional constant], and in the control range of (B), the q-axis current command I _q ,
In addition to the relationship of I _q1, d-axis current command I _d1, the d-axis current command I _d0 in order to suppress the synchronous motor terminal voltage _{V M, I d0 = K d2} × K d3 × (N-N base) / ( N _top −
N _base ) [where K _d2 and K _{d 3} are proportional constants], and the d-axis current command I _d is defined as I _d = I _d0 + I _d1 to perform vector control. A method for controlling a synchronous motor, wherein _{Kd3 is made} to be one or more variables during acceleration and is increased or decreased in proportion to the rotation angle N. Wherein the proportionality constant K _d1, K _d2 negative (-) to, and becomes a synchronous motor control target, the direct-axis (d-axis) inductance L _d is the horizontal axis (q-axis) than the inductance L _q 2. The synchronous motor control method according to claim 1, wherein the method is applied to a permanent magnet synchronous motor having a saliency in which L _q > L _d is small.