JPH03245792A - Controlling method for motor - Google Patents

Abstract

PURPOSE:To give quick-response properties equal to conventional vector control by a simple circuit by controlling the phase of three-phase ACs so as to keep a spatial angle formed by a position, where the value of the spatial distribution of armature reaction magnetomotive force is maximized, and the direct-axis of a rotor constant and controlling the instantaneous value of the amplitude of three-phase ACs. CONSTITUTION:In a method in which three-phase ACs made to flow through a three-phase winding are controlled by an inverter, the phase of the three-phase ACs controlled so that a spatial angle formed by a position, where the value of the spatial distribution of armature-reaction magnetomotive force generated by currents made to flow through the three-phase winding is maximized, and the direct-axis of said rotor is kept at a fixed value. The instantaneous value of the amplitude of the three-phase ACs is controlled directly apart from the control, thus controlling instantaneous torque.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing electric motors such as synchronous motors, internal Stastone permanent magnet motors, and reluctance smorphs.

B.

Summary of the Invention When three-phase alternating current is caused to flow through the three-phase winding provided in the stator core by an inverter, the position where the value of the spatial distribution of the armature reaction magnetomotive force due to this three-phase alternating current is maximum, and the position directly under the rotor. By regulating the phase of the three-phase AC so that the spatial angle of The operating characteristics have also been improved.

C1 Conventional technology and its problems Conventionally, so-called vector opening has been widely used as a speed control method for AC motors that have excellent opening performance equivalent to that of DC motors.

This vector control ζ: is based on the principle of detecting the vector of magnetic flux, adjusting the magnetizing current so that the magnitude of the magnetic flux is constant, and flowing a torque current proportional to the required torque at right angles to the magnetic flux. Magnetic flux vectors and current vectors are calculated from various circuit constants.

However, when performing this vector control,
In the process, dq conversion, two-phase three-phase conversion, or various calculations are performed, so there is a problem that the control circuit is complicated and adjustment is time-consuming.

The present invention is directed to a method for controlling a synchronous motor, an internal magnet type permanent magnet motor, or a reluctance motor, which uses a simpler circuit than the above-mentioned vector control, has the same long-range performance as vector control, and has improved operating characteristics. The purpose is to provide.

D. Means for Solving the Problems The present invention, which achieves the above-mentioned objects, comprises a stator having a three-phase winding in the stator core, a rotor having magnetic poles formed by field windings, and A three-phase motor that has a rotor with permanent magnets embedded as magnetic poles in the rotor, and one rotor that does not have magnetic poles and has different magnetic reluctance between the direct axis and the horizontal axis, and the three-phase winding has In the method of controlling alternating current using an inverter, the spatial angle formed between the position where the value of the spatial distribution of the armature reaction magnetomotive force generated by the current flowing in the three-phase winding is maximum and the direct axis of the rotor is set to a constant value. The present invention is characterized in that the instantaneous torque is controlled by regulating the phase of the three-phase alternating current so as to maintain the amplitude of the three-phase alternating current, and directly controlling the instantaneous value of the amplitude of the three-phase alternating current independently of the parenthesis control.

E. Action and Principle The phase ωt is determined so as to keep constant the spatial angle φ between the position where the value of the spatial distribution of the armature reaction magnetomotive force is maximum and the direct control of the rotor, and this phase ωt'' and the command angular velocity ωJ With the current amplitude 18' based on the three-phase winding current 1:, 1,7
By obtaining , , g and controlling the inverter, the instantaneous torque of the electric motor can be controlled.

Here, the principle of the present invention will be explained as follows by further embodying the above-mentioned effect.
This will be explained below with reference to the figures.

Figure 1 is an explanatory diagram showing the relationship between the magnetomotive force and the gap magnetic flux density of a synchronous machine.The lower part shows a part of the rotor, and the upper part shows the q-axis (horizontal axis ) d axis (
It shows the relationship between magnetomotive force, etc. In Fig. 1, Fl is the reaction magnetomotive force due to the armature current and rotates in synchronization with the rotor, F is the fundamental wave component of the rotor magnetomotive force, and Bg is the composite magnetomotive force of the magnetomotive force F and F2. The fundamental wave component of the gap magnetic flux density caused by &C is the armature current density distribution. Among these, the angle δ between the d-axis and the peak of the gap magnetic flux density Bg is the internal phase difference angle, and conventionally, the synchronous machine theory is constructed using this internal phase difference angle as a parameter.

In the present invention, a theory is constructed using the phase difference φ between the d-axis and the peak of the armature current magnetomotive force F as a parameter. Since this is also the peak position of the reference d-axis birotor magnetomotive force F2, φ is also the phase difference (referred to as magnetomotive force phase difference angle) between the re-magnetic forces F1 and F2.

To express the torque using this magnetomotive force phase difference angle φ, a three-phase alternating current l shown by the amplitude 17 of the following equation (1) is applied to the stator three-phase winding of the synchronous machine. , 11. The generated torque T when l is flowing is (2)
The formula becomes

...(2) In this case, P is the number of pole pairs, K is a constant determined by the design specifications, and B
f, is the peak value of the fundamental wave component of the gap magnetic flux density generated by the field magnetomotive force, L, 6 is the direct armature reaction inductance, and Lso is the horizontal axis armature reaction inductance.

This equation (2), torque T, is a general equation that holds true for all synchronous machines. This is a reaction torque that exists only when the q-axis has a different magnetic resistance.

Therefore, in the case of a cylindrical rotor, the second term does not exist, and in the case of a reluctance motor, only the second term exists. As can be seen from the equation, if the current phase is controlled to keep the magnetomotive force phase difference angle φ constant, the torque T will be the instantaneous value l of the current amplitude.

It will depend on.

Here, if all spatial angles are expressed in electrical angles and the angular velocity ~ of the rotor is also expressed in electrical angles, in order for the armature reaction magnetomotive force F to rotate in synchronization with the rotor, the current equation (1) must be ω
must be equal to vomit.

Also, in the stator, with the winding axis of the U-phase winding as the origin,
When considering the stator coordinates expressed in electrical angles, and assuming that the d-axis position θ6 in this coordinate system is the d-axis position, the following equation (3) can be obtained in an operating state where φ is constant.

θ=ω is −φ (3) Therefore, according to this equation (3), if θ6 is detected by the sensor and kept constant and φ is set to φ′, then the equation (4) is obtained.

(ωt Bi=Nailt=θ.+φ1...(4) In this way, the command value (ωt, etc.) can be obtained.

Therefore, if the phase of the current flowing through the three-phase winding is controlled so that (ωt) in equation (1) becomes (ωt) in equation (4), the armature reaction magnetomotive force F1 will be equal to its peak value and the d-axis It is possible to rotate at an angular velocity in synchronization with the rotor while maintaining an angle of φ" between the rotor and the rotor.

As a result, φ can be kept constant by the phase core of the current, and at this time, from equation (2), the instantaneous value of the torque is determined depending on the instantaneous value 1 of the current amplitude. Therefore, the instantaneous value of the current flowing through the three-phase windings of the stator is 1. , l9.
The instantaneous torque of the electric motor can be controlled by arranging the ishiverter so that l satisfies the following equation (5).

F.

Embodiment Here, one embodiment of the taxidermy method according to the present invention will be described with reference to a specific control circuit. Current medullary type inverter 20
The electric motor 21 is controlled by the position detecting device 22, which is equipped with the electric motor 21.
The rotor's d-axis position θ. is obtained. Current phase calculation circuit g8
23, the preset magnetomotive force phase difference angle command value φ
From two ROM tables created based on 9,
Output at the input θ.

On the other hand, the signal from the position detector 22 is changed to FV t! 11. The rotational angular velocity signal ω6 is obtained by converting the signal in the converter 24. This speed signal is compared with the speed command value ωE, and the current amplitude l! is used to obtain the necessary torque via the PI controller 25! Get it.

This amplitude 1: and multiplying form/A change￥j26
The current command values 1: and l: of cao (θ, +φ゛) and D/A converted are obtained. And i + i −
', using the relationship i = O 1: From the arithmetic circuit 27,
A V-phase current command value 19' is obtained.

If the voltage source inverter 20 is controlled to supply current to the motor 21 according to the command values l:, l;, l:, even if the load torque fluctuates, ω! Be able to operate stably at an angular velocity of

Also, since the formula for torque T is independent of frequency, PI
A limiter 28 is provided on the output side of the controller, and a constant torque can be generated by flowing a constant current value during acceleration and deceleration.

Further, in this embodiment, the i and t hysteresis converters 29
According to the sign of (ωJ-ω,,), if it is positive, the value of φ'' is also assumed to be positive and the motor is accelerated, and if it is negative, the value of φ'' is also assumed to be negative and the generator is accelerated. It uses regenerative braking when driving.

Although this embodiment can be applied to all rotating machines having the structure of a synchronous motor or a reluctance motor, the optimum value of φ is selected depending on the structure. In this case, a value of φ is selected that is close to the value of φ that produces peak torque and has good characteristics such as efficiency and power factor. Additionally, instantaneous overload can be handled by setting the power supply voltage so that a corresponding current can flow.

G.

Details of the invention As explained above, the present invention has the following effects.

(1) It should be possible to control instantaneous torque using a significantly simpler control method than vector division.

(2) Conventional synchronous motors: A damper winding is provided in consideration of starting, synchronous pull-in, and explanation, but this method detects and controls the position of the two rotors, so There are no problems like this at all. Therefore, no damper winding is required, which simplifies the structure. In addition, in conventional synchronous motors, the rated torque is approximately 1/1.5 to 1/2 of the peak torque in consideration of tax regulations, but with this method, the rated torque can be set to a torque close to the peak torque. The electric motor can be made smaller;S.

(3) Operating characteristics such as efficiency and power factor can also be improved compared to conventional synchronous machines.

As is clear from the above, this method can have excellent characteristics with a simple control circuit, and can also save resources and energy.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention, and FIG. 2 is a control circuit diagram for implementing the present invention. In the figure, Fl: armature current magnetomotive force, L: rotor magnetomotive force, B is gap magnetic flux density, 21 is a motor, 23 is a current phase calculation circuit, and 24 is an F/V converter.

Claims (1)

[Claims] A stator with a three-phase winding in the stator core, a rotor with magnetic poles formed by field windings, a rotor with permanent magnets embedded as magnetic poles inside the rotor core, and magnetic poles. In the method of controlling the three-phase alternating current flowing through the three-phase winding with an inverter, the three-phase alternating current flowing through the three-phase winding is controlled by an inverter. The phase of the three-phase alternating current is controlled so that the spatial angle between the position where the value of the spatial distribution of the armature reaction magnetomotive force generated by the current flowing through the windings is maximum and the direct axis of the rotor is maintained at a constant value. , and controlling instantaneous torque by directly controlling the instantaneous value of the amplitude of the three-phase alternating current independently of this control.