JPS60176489A - Control system of synchronous motor - Google Patents

Abstract

PURPOSE:To remedy to an ultrafine torque command by forming the product of a current amplitude, a magnetic flux density of a rotor and a cosine value of the phase difference of a current flowed to a stator winding proportional to the torque command so that the torque generated in a synchronous motor coincides with the torque command. CONSTITUTION:A current amplitude IA is calculated by a calculator 20 on the basis of a torque command T and the prescribed value TL, and the magnetic flux density of a rotor and the cosine cosalpha of the phase difference alpha of the current flowed to a stator winding are calculated by a calculator 21. A 3-phase sinusoidal wave generator 2A generates sinusoidal wave signals s1-s3 in which the phases are displaced at 120 deg. for deciding the phase of the current flowed to the stator winding and the frequency corresponding to the rotating position of the rotor. The current of the stator winding is controlled so that the product of the torque T, the current amplitude IA and the cosine value cosalpha are proportional.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for a synchronous motor that can reduce the influence of a dead zone of a control device and precisely control even minute torques.

- Figure 1 shows the schematic structure of a synchronous motor, in which the stator windings Z2 and Z3 are wound in three phases on the stator 30, and three-phase alternating current is supplied from the control device. It has become. This current is caused to flow in synchronization with the position of the magnetized rotor 31, and due to the interaction with the magnetic flux generated by the rotor 31, Figure 2 shows a conventional example of such a control device for a synchronous motor. The torque command T is amplified by an amplifier 1, becomes a command IA for the amplitude of the winding current flowing through the stator windings 21 to Z3, and is input to the multipliers 3 to 5. On the other hand, a position detector 1 connected to a synchronous electric file
The position DP of the rotor 31 detected by 8 is input to the three-phase sine wave generator 2, and the position DP of the rotor 31 detected by the stator @1! lZl, Z2
and a sine wave signal Sl whose phase is shifted by 120°, which determines the frequency of the current flowing through Z3.

S2 and S3 are generated and multipliers 3.4 and 5, respectively.
is input. For the first phase, the current amplitude IA from the amplifier 1 and the sine wave signal Sl from the three-phase sine wave generation circuit
is multiplied by the multiplier 3 and becomes the current command Ril. This current command Ril is input to the adder 6, and the current 11 of the first phase Z1 of the stator winding detected by the current detector 15 is inputted to the adder 6, and the stator current i1 is inputted from the current command Ril. The current deviation Eil from which is subtracted is input to the PI loco controller 9. Then, the PID controller 9 performs a compensation calculation, and the result is transmitted to the power amplifier 12.
A required voltage v1 is applied to one end of the . Further, the second phase and the third phase are also exactly the same as described above.

and a power amplifier 12. ' 13 and 14, the first phase Zl, the second phase Z2 and the third phase Z3 of the stator winding are
As shown in the figure, the wires are connected in a Y-shape and are connected in parallel.1 For example, the stator winding Z1 of the first phase has the voltage Vl of the power amplifier 12 and the neutral voltage of the stator windings 21 to Z3. Point N
A stator current i1 flows according to the potential difference between the voltage and the voltage vO. The same applies to the stator currents 12 and i3, and rotational torque is generated in the rotor 31 due to the interaction between the stator currents 11 to 13 and the magnetic flux generated by the rotor 31.

In such a configuration, the current amplitude IA is generated based on the torque command T given to the control device. In addition, sine wave signals Sl, S with frequencies corresponding to the rotor position port P
2 and S3 are generated and multiplied by the current amplitude IA by multipliers 3, 4 and 5, respectively, to become current commands Ril, Ri2 and Ri3. Based on the current command Ril, the adder 6
．． A stator current i1 flows through the first phase stator winding Zl through a current feedback system consisting of a PID controller 9, a power amplifier 12, and a current detector 15. The stator current is 1 for each third phase.
2 and i3 are flowing.

Assuming that the frequency of the three-phase sine wave generating circuit 2 is ω/2π, the impedances of the stator windings 21-23 are the same, and normal current control is performed by the current feedbar system, generally, It works. The rotor 31 is rotated at an angular velocity ω by these stator currents i1 to i13. At time 0, the generated w of the rotor 31
Assuming that the direction of the f-gap density B is parallel to the stator winding 21, the magnetic flux densities 81.82 and B3 perpendicular to the stator windings Zl, 22 and Z3 are respectively (however, BA is the magnetic flux The size of density B) becomes.

Here, assuming that the average radius and effective length of the stator winding Zl-23 are all the same and R and L, respectively, the rotational torque TM applied to the rotor 31 is.

From formulas (IA) ~ (Ic) and (2A) - (2C), Ta -L ・R・ (Bl −th +B2 ・i
2 + B3 ・ 13) = Yes L @ R-BA*
IA fist cascx=Ka IA・cosa −,
, shout 3) (However, = jL-R-BA).

The three-phase IF sinusoidal wave generation circuit 2 generates the 11-single wave signal Sl so that there is no phase difference between the rotation of the rotation f31, that is, the rotation of the magnetic flux density B, and the fixed I'1L flow 11. 4
As shown in Figure 12, it is α-0, and the formula % is expressed as follows. Therefore, in order to generate the rotational torque TN to match the torque command T, the current amplitude IA should be set as IA=i ・T, . . . old . . . (5) as shown in Fig. 5. . As can be seen from equation (5), when it is necessary to generate a minute torque, the current amplitude IA is also minute, and as seen from (IA) to (IC), in this case, the stator winding Zl, Current i1. flowing through Z2 and Z3. i
The amplitudes of 2 and i3 are minute.

However, as shown in FIG. 6, which shows the human output characteristics of the gravity amplifiers 12 to 14, for example, there is a dead zone in which the output Vo does not change when the input v1 is small, and the small upstream control j# ■Cannot be done. Therefore, the conventional Flj control device has the disadvantage that it cannot respond to the minute torque command T.

Therefore, the purpose of this emitting j is without the drawbacks mentioned above,
Coping with minute torque commands T1. Get 40I+ '*l
i: To provide a motivation control method.

This invention will be explained below.

This invention applies a torque command T to a fixed winding of a synchronous motor consisting of a stator, a stator-45 wire wound around the stator in a Sanwa winding, and a magnetized rotor. This relates to the iIU method for controlling synchronous motors, which determines the amplitude TA of the current, and determines the phase and frequency of the stator winding current from the rotor position of the rotor. In order to match the torque command T, the product iA cosα of the current amplitude IA and the cosine value cosα of the magnetic flux density of the rotor and the phase coefficient α of the current flowing in the delimiter winding is
is made proportional to the torque command T.

No. 71Δ shows a schematic configuration of an embodiment for realizing the method of the present invention, corresponding to FIG. At the same time, 1iif 'i'L equipment 2j is manually operated. Furthermore 1. The signal (Feat) from the 1-lux unit, etc. is also input manually to the operator 20, and is also input to the 1IITQ unit 21. If the absolute value of the torque command T is less than or equal to the constant value TL, the ia flow amplitude IA is generated in proportion to the torque command T to satisfy equation (5), and if the absolute value of the torque command T is less than or equal to the constant value TL, the torque When the command T stops or stops, the current amplitude IA is set to a constant value IL, and when the torque command T is negative, the current amplitude IA is set to a constant value -IL and is input to the multipliers 3-5.

- As shown in FIG. 9, when the absolute value of the torque command T is greater than a constant value of 41 to TL, the cosine value CO5α of the phase difference α, which will be described later, is set to 1, and the torque command T is set to 1. If the absolute value is less than or equal to the fixed value TL, then when the torque command T is zero or positive, cosa; ...As (7), a string wave is generated on the 3-phase 1 - 1 path 2 is manually powered. Therefore, between the current amplitude IA, the cosine value cosα of the current amplitude IA・cosa, and the torque command T, there is j? As shown in the JlO diagram, the following relationship holds true: T = K #IA-casa --- (8). However, K is the same as in equation (5).

Next, the 3-root string wave generation circuit 2A is at the rotational position DP.

Correspondingly, a sinusoidal signal 5l-53 with a phase shift of 120° is generated which determines the phase and frequency of the current flowing in the stator winding Zl-23, or the conventional three-root signal shown in FIG. As in the string wave generation circuit 2, the magnetic flux density B of the rotor 31,
11th without matching the phase with the sine wave signal Sl.
As shown in the figure, the cosine value cos input from the calculator 21
The 1F sinusoidal signal S1 is advanced by a phase difference α that gives α.

Then, the sine wave signal 5l-8 generated in this way
3 are input to multipliers 3 to 5, respectively.

And, from Kagaki 3 to 5 onwards, it is the same as before.

In such a configuration, the I-lux command T and the constant value TL
'l! by the arithmetic unit 2o based on 'l! : The m amplitude IA is multiplied by 11, and the cosine value cosα is calculated by the computing unit 21 based on the torque command T and the constant 1 (iTL).

Then, in the three-phase iIE sinusoidal wave generation circuit 2A, based on this cosine value cosα and the rotation value position, the three-phase Sine wave signals s1 to S3 are generated, and the current amplitude is IA and the phase is s1 to s1, respectively, as in the conventional example.
Current 1 of 1υ constant winding Zl~Z3 to match s3
1 to 13 are controlled.

At this time, the generated torque TM of the synchronous motor is given by the equation (3) as described above, and the current amplitude IA and the cosine value cosα are set in advance by the calculators 20 and 21 so as to satisfy the equation (8). However, the generated throat torque TM coincides with the desired torque command T. Moreover, as shown in Fig. 8 and Fig. 91Δ, the small torque command T is dealt with by keeping the current amplitude IA at a constant value If or -■ and varying the cosine value cosα. Therefore, current control can be performed by the upstream foot puncture system without making extensive use of the dead zone regions of the L force amplifiers 12 to 14 shown in FIG.

In addition, the above-mentioned computing units 2o and 21 calculate the relationship between the torque command T and the current amplitude ■^, and the relationship between the torque command T and the cosine value α, respectively.
The relationship with is set as shown in Figures 8 and 9, but
It is not necessarily limited to this. In other words, the product IA of the torque command T, the current amplitude IA, and the cosine value CO8α
For example, the relationship between the I-Luke finger 4T and the current amplitude IA is shown in Figure 12, and the relationship between the I-Luke command T and the cosine value CO3α is shown in Figure 13.
The settings may be made as shown in the figure. Also, since cosα and C05(-α) are equal, 1F
The rotation number S1 is advanced by phase -α from the magnetic flux density of rotation 1'31. In other words, (q (even if the phase α is delayed)
Is there an effect similar to that of 2d\? Stator -af (iIZ1
Considering the inktance of ~Z3, it is easier to control the force that advances the 11th string wave S1 by the phase α than the magnetic flux density.

According to the control force formula of this invention, as shown below.

When it is necessary to generate a minute I-lux, the current amplitude applied to the stator winding is kept at a constant value instead of being made minute as in the conventional case. This has the advantage that it is possible to perform good current control without using much of the non-transferable band region present in the power amplifier or the like in the control device.

[Brief explanation of drawings]

Fig. 1 is a schematic structural diagram of a synchronous motor, Fig. 2 is a diagram showing an example of a conventional synchronous motor control device, Fig. 31Δ is a diagram for explaining how the power amplifier and stator winding are connected, Fig. 4
181 is the magnetic flux of the rotor in the conventional device! ? -: Diagram showing the phase relationship between degree and stator a-line current, Figure 5 is a diagram showing the relationship between conventional torque command T and tW flow amplitude IA, and Figure 6 is
The figure shows the power amplifier's insensitivity/j1? FIG. 7 is a block diagram of an embodiment for realizing the method of the present invention, and No. 81N shows the relationship between the torque command T and the wave amplitude IA according to the method of the present invention. FIG. 9 shows the torque command T and cosine (IIjcosα) according to the method of this invention.
Figure 10 shows the relationship between the torque command T and the product of the 1E flow amplitude IA and the cosine m cos α, Iy5, and Figure 11 shows the relationship between the rotor magnetic flux density and A diagram showing the phase relationship of the current in the stator winding, FIG. 12 shows another torque command T and current amplitude IA according to the method of this invention.
FIG. 13 is a diagram showing the relationship between another torque command T and cosine value cosα according to the method of the present invention. l...Amplifier, 2,2A...3 root string wave generation circuit,
3-5... Multiplier, 6-8... Adder, 9-11.
... PID controller, 12-14... Power amplifier, 15-17... Current detector, 18... Synchronous motor, 19... Position detector, 20.21... Arithmetic unit, 3
0... Stator, 31... Rotor. Applicant's agent: Karito Ni Yasugata. Na l Illustration 3 Figure f (No. 5 ΩI A Certain 6 Figure O L 6 Figure IA Vines 9 Figure 1 Leather !θ Figure 11 Mouth vines /2 Figure IA ・Courtesy /3 Deputy CO8ba↑

Claims (4)

[Claims] (1) For a synchronous motor consisting of a stator, a two-phase winding wound around the stator, and a magnetized rotor, a torque command T is applied to the stator winding. In a control force equation for a synchronous motor that determines the phase and frequency of the current in the 8 wires of the stator based on the rotational position of the rotor based on the amplitude IA of the flowing current, the generated torque TM of the synchronous motor is the torque command In order to match T, the product IA・c of the current amplitude IA +3ij and the cosine value cosα of the magnetic flux sonicity of the rotor and the phase difference α of the current flowing through the stator winding.
A control method for a synchronous motor, characterized in that osα is made proportional to torque command T described in F311. (2) Absolute of the torque command T (when M+ is greater than a constant value T, the absolute value of the cosine value cosα is constant 3°, and the absolute value of the current amplitude IA is proportional to the absolute value of the torque command T) When the absolute value of the torque command T is less than a constant value TL, the absolute value of the current amplitude IA is made constant and the absolute value of the cosine value cosα is made proportional to the torque command. The torque command T
By making it proportional to the absolute value of aIA・cos
A control method for a synchronous motor according to claim 1, wherein α is made proportional to the torque command T. (3) The control force formula for a synchronous motor according to claim 2, wherein the current amplitude IA and the torque command T have the same sign, and the cosine value cosα is non-negative. (4) A control method for a synchronous motor according to claim 2, wherein the cosine value cosα and the torque command T have the same sign, and the current amplitude IA is non-negative.