JPH0345180A - Control of driving of variable air gap motor - Google Patents

Abstract

PURPOSE:To obtain a high torque by a method wherein 120 deg. square wave is produced by a minimum air gap position detecting signal and the maximum exciting point is set near the point of 60 deg. before the maximum exciting point. CONSTITUTION:The optimum driving of a variable air gap motor is effected by a speed command and a 120 deg. square wave, obtained by amplifying the output of a speed detector through a PI amplifier to obtain a torque command and inputting it into a control circuit CNT. The control circuit CNT obtaine a minimum air gap position signal GC employing 6 sets of position detectors PS and converts it into a driving current phase command through a converter T. An exciting phase angle is determined by setting the maximum exciting point at the center of the square wave to a point near 60 deg. before generating the minimum air gap position.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention provides maximum control of motor torque! The present invention relates to a drive control method for a variable gap motor that allows IifI41m.

B. Summary of the Invention In a variable gap motor that magnetically attracts a rotor to a stator, the minimum gap position is detected, and the position is determined based on the detected signal.
When a 20° square wave current is applied, the strongest excitation point is set at around 60° from the minimum air gap position, so that the motor torque can always be controlled to the optimum state.

C9 Prior Art The inventor of the present application has developed a variable gap motor (the origin of this name will be described later) that can obtain low speed and high torque output. The principle of the variable gap motor will now be explained with reference to FIG. As shown in the figure, a conical rotor cone 2 made of a ferromagnetic material is arranged in a fixedly installed conical stator cone 1, and the top of the rotor cone 2 is supported so as to be rotatable and swingable. . Furthermore, J of stator cone 1
Coils 01 to C6, which serve as electromagnets, are arranged around R.

C1, C2 → C3, C4 → C3-C6
When the rotor cone 2 is sequentially shifted while circulating as shown in →C1, the rotor cone 2 is attracted by the energized coil and moves along the inner circumferential surface of the stator cone 1. In other words, rotor cone 2
rotates in the direction of arrow ■ while moving the contact position in the direction of arrow ■ in the figure. The rotation speed of the rotor cone 2 is much smaller than the contact movement speed (this rotation speed becomes smaller as the difference between the apex angle a of the stator cone 1 and the apex angle β of the rotor cone 2 becomes smaller. By taking out as an external output, it is possible to realize a motor with low speed and high torque motor output.In this motor, as the rotor cone 2 moves, the gap between the stator cone 1 and the rotor cone 2 changes. Therefore, this type of motor is called a variable gap motor.

A conventional example of a variable gap motor that rotates based on the above-mentioned principle will be explained with reference to FIG. As shown in the figure, the shaft 10 is supported by a frame 12 via a radial bearing 11, and the shaft 10 is equipped with two rotor cones 14 via special bearings (detailed structure will be described later) 13. There is. This rotor cone 141 is provided with a core 14a to facilitate passage of magnetic flux. Special bearing 1
3 allows the rotor cone 14 to swing in the axial direction, but has a function of rotating the rotor cone 14 integrally with the shaft 1° in the circumferential direction. The stator 15 is fixed to the frame 12 and located between the two rotor cones 14. A plurality of coils (electromagnets) are arranged in the stator 15 along the circumferential direction. Furthermore, stator cones 16 on which the rotor cone 14 rolls are fixed to both ends of the stator 15.

The special bearing 13 is shown in an exploded view in FIG.
As shown in the cross-sectional view in the figure, the main components are an inner circle f@13a, an outer circle @13b, and a sphere 13c. A plurality of aligned hemispherical recesses 13d are formed in the circumferential direction on the outer peripheral surface of the inner cylinder 13a and the inner peripheral surface of the outer cylinder 13b, and the sphere 13c is inserted into the hemispherical recesses 13d. . Then, the inner circle @ 13 m is fixed to the shaft 10, and the outer cylinder 13b is fixed to the rotor cone 14. In this way, the rotation of the rotor cone 14 is transmitted to the shaft 10, and the rotation of the rotor cone 14 is transmitted to the shaft 10.
can swing in the axial direction.

In the variable air gap motor having the above configuration, when the excitation of the coils of the stator 15 is sequentially shifted in the circumferential direction, the rotor cone 14 is attracted to the excited coils, and the rotor cone 14 is attracted to the excitation coils.
4 rotates while contacting the stator cone 16. The rotation of the rotor cone 14 is then transmitted to the shaft 10, and the shaft rotation becomes an external output.

D. W1m to be Solved by the Invention In the variable gap motor described above, it is necessary to detect the minimum gap position of the rotor with respect to the stator when driving the rotor. That is, for example, if the strongest excitation is performed at the minimum gap position, the attractive force at that position becomes large, but the desired rotor torque cannot be obtained.

In other words, by changing the phase angle between the minimum gap position and the strongest excitation position, the generated torque changes, and by setting this phase angle to an appropriate constant value, the highest torque can be obtained.

The present invention provides a drive control method for a variable gap motor that controls the excitation phase angle to be constant in order to obtain the optimum torque.

E.

Means for Solving the Problems The present invention achieves the above-mentioned objects by creating a 120° square wave with the minimum gap position detection signal, and by converting the I&
Basically, the strong excitation point is set near 1160° where the minimum air gap position occurs.

F.

The state of being attracted to the next magnetic pole along the working contact movement position is 60
By setting the excitation phase angle around °, the motor output torque can be set to high torque, and the torque can be maintained in the optimum state at #
I can control it.

Here, the principle of drive control will be described with reference to FIGS. 5 to 7. Figure 5 shows the plane of a six-pole motor, Ntff3,
Three magnetic poles are assigned to each of the S poles, and for example, when the coil C1 is energized, the coils C6 and C2 are also energized, and magnetic flux passes through the magnetic poles (6) and (2) with respect to the magnetic pole (1). In this case, if the rotor is attracted by the magnetic poles (4) as shown in Fig. 5, and then the attracted state (contact state) is moved counterclockwise, the energization of coil C3 is With magnetic pole (3) as the center, magnetic pole (2), (4
1 = In other words, the excitation changes in order in the counterclockwise direction. FIG. 7 shows the state in which the coils are energized to each magnetic pole.

FIG. 6 shows a circuit for energizing the coils 01 to C6, which uses so-called power transistors.
Equipped with 6 quadrant circuits and 12 coils 01 to C6.
08 is made to flow. Here, IIS indicates the current detected by the current detector, and is the same as I□ shown in I□ to ■f6 in FIG.

G.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to FIGS. 1-4. FIG. 1 is an overall configuration diagram when applied to a speed command, and shows the speed [11@ omitted] by a variable gap motor.

That is, the speed command and the speed detection 11 of the variable gap motor M
! (Pulse encoder) The F/V converted output of PE is added at a summing point A, the PI is intensified, and the torque command IF is output to the control circuit CNT. This control circuit CNT performs optimal wA operation using a 120" square wave based on the signal from the position detector PS from the motor M. Here, the position detector PS has a capacitor installed and applies high frequency to adjust the impedance. It is formed by attaching a piezoelectric element to the rotor contact surface.

Among these, the control circuit CNT has the configuration shown in FIG.
Here, the minimum gap position signals GCI to GC6 are obtained using the 6aI detector PS, and this minimum gap position signal is converted l#Tζζ to reshape the drive current phase command consisting of I,, I,, I. ing. In this modification, an excitation current of 120° is obtained by the circuit shown in FIG. 3 based on each signal GC1 to GC6 of the detector PS as shown in the time chart shown in FIG. That is, for example, the current I '13 is made by No. 43 GC1 and GC3, and the current
is created by signals GC2 and GC4. In other words, the RS flip-flop FFI is set and reset using the signals GC5 and GCl, and the current Ifl is obtained.
Ie is inverted and the voltage by signal GC2゜GC4 is ``f4''.
is added and further passed through the inverting amplifier A2. You should get it.

In this case, when considering the optimum excitation in the direction of movement of the contact position of the rotor with respect to the minimum air gap position, the strongest excitation point, for example, the center of the rectangular wave (3) and the minimum air gap position are 6
Since the highest torque occurs near 0°, the current If3
The strongest excitation point has a relationship of δ (excitation phase angle) of approximately 60'' with respect to signal GC3.

Currents I,1 to 16 and signals GCI to GC6 all have the same relationship.

In this way, the current phase commands I, I created by conversion @sT
, I enter the multiplier
Be separated into 0. And this current I□~■111 is 2
The current is input to each current f#ll11 circuit having one circuit, a comparator CP, and a two-quadrant chip circuit, and the current current from the current detector is taken into consideration to excite the coils 01 to C6.

In this way, the coil can be excited with a drive current that takes into account the excitation phase angle δ between the minimum gap position and the strongest excitation point.

H9 As described in detail, according to the present invention, by setting the excitation phase angle to the optimum value, the motor torque can always be controlled in the optimum state, and the output torque can be controlled only by the amplitude command, so that the DC Speed control similar to that of a machine is possible.

[Brief explanation of drawings]

Figure 1 is an overall configuration diagram for moderate control, Figure 2 is a control circuit configuration diagram for one embodiment, and Figure 3 is a conversion of Figure 2 @T.
FIG. 4 is a time chart in the conversion WiT, FIGS. 5 to 7 are diagrams explaining the principle of driving, and FIGS. 8 to 11 are diagrams explaining the principle of the variable gap motor. In the figure, CNT is a control circuit, ps is a position detector, GCI to GC6 are minimum gap position detection signals, I, 111
c is the excitation current phase command, 'fl~' (Im is the excitation current. Fig. 3 Al, A2 Inverting amplifier (1bJc l KatsuLl is also an open collar circuit) Fig. 4 Time chart familiar) Jun δ = 60 deg Figure Figure Figure [C1, C3, C5 and C2, C4, C6 are currents in opposite directions] Figure 8 Rotation principle Red diagram Conventional technology 0 Figure 11

Claims (1)

[Claims] A detector detects the minimum air gap position detection signal of the rotor relative to the stator, a 120° square wave current is created using this minimum air gap position detection signal, and each magnetic pole is excited with this 120° square wave current. A method for controlling the drive of a variable air gap motor, characterized in that the strongest excitation point is set at around 60 degrees before the generation of the minimum air gap position detection signal at the magnetic pole.