JPH0356818A - Rotation angle detecting device - Google Patents

Abstract

PURPOSE:To detect an angle of rotation with high accuracy without using any secondary winding by leading an AC signal which excites respective projection poles of respective exciting projection pole couples and a signal which includes variation in the inductance of the windings as a variable out of the mid-points of the windings. CONSTITUTION:Exciting projection pole couples A and C of the stator 3 of a resolver 1 are wound with windings LAC1 and LAC2 differentially and exciting projection pole couples B and D are wound with windings LBD1 and LBD2 differen tially. A rotor 5 is arranged in the inner peripheral space of the stator eccentrically with the rotary shaft of a motor. The windings LAC1 and LBD1 are applied with a sine wave signal VSTD from a reference signal generator OSC and the windings LAC2 and LBD2 are applied with the signal VINV generated by inverting the sine wave through OP. Then composite signals VNAC and VNBD are outputted from the mid-point NAC of the windings LAC1 and LAC2 and the mid-point NBD of the windings LBD1 and LBD2 to an R/D converter RDC. The converter RDC outputs the rotational angle signal theta dig of the rotor 5 from the signals VNAC and VNBD.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an electromagnetic rotation angle detection device for detecting the rotation angle of a rotating machine.

[Conventional technology] L size compared to conventional electromagnetic rotation angle detection devices that detect the rotation angle of rotating machines such as motors (Company). wire (output winding)
There are so-called brushless resolvers, each equipped with a rotating transformer, and a nolactance resolver, which has a primary winding (excitation winding) on the stator salient poles, and a secondary winding (output winding) in series with the primary winding. Resolvers are known. In the case of a brushless resolver, the phase difference between the reference AC voltage applied to the primary winding and the spiritual pressure generated in the secondary winding due to electromagnetic induction changes depending on the rotation angle of the rotor. In the case of a reluctance-type resolver (t.), due to the inductance of the primary winding that changes as the rotor rotates, a phase difference occurs between the reference AC signal applied to the primary winding and the output signal of the secondary winding. is used to detect the rotation angle of the rotor, which rotates integrally with the rotating shaft of the rotating machine.

[Problems to be Solved by the Invention] However, since each of the above-mentioned resolvers is provided with a secondary winding, the problem arises that the size and weight of the device increases, and an extra load is applied to the rotating machine. In addition, in the case of brushless resolvers, there is a problem with reliability because there is a moving part called a rotating transformer.

Of course, in the case of a reluctance type resolver (using a current detection resistor instead of the upper secondary winding), it is possible to detect changes in inductance due to the rotation of the motor as changes in current, but this is detected by the heat generated by the resistor. Since a so-called temperature drift occurs in which the characteristics of the signal change, there is a problem in using it for highly accurate rotation angle detection.

Present Invention 1 An object of the present invention is to provide a rotation angle detection device that does not require a secondary winding and is capable of highly accurate rotation angle detection [Means for Solving the Problems] Summary of the present invention A stator is provided with a plurality of excitation salient pole pairs each having windings wound differentially, and a rotor that changes the inductance of the winding of each of the excitation salient pole pairs according to the rotation angle. In the rotation angle detection device, an excitation means for exciting each of the two salient poles in each of the excitation salient pole pairs with alternating current signals having mutually different phases; A rotation angle detection device comprising: rotation angle signal generation means for generating a rotation angle signal of the rotor based on a composite signal of the above two AC output signals.

[Function] The rotation angle detection device of the present invention configured as described above allows 1f. The excitation means excites each of the two salient poles in each excitation salient pole pair with alternating current signals having mutually different phases. Therefore, when the rotor rotates, the inductance of the winding of each salient pole changes in each exciting salient pole pair at a period corresponding to the rotor's rotational speed. In other words, the periodic change in the inductance of each winding is expressed as a function of the rotation angle of the rotor. Due to periodic changes in the inductance of this winding, a composite signal 1 is output from the midpoint of the windings differentially wound in each excitation salient pole pair. A signal that has as variables a change in inductance and an AC signal. becomes. Based on this composite signal,
The rotation angle signal generation means generates a rotation angle signal of the rotor.

[Example] An example of the present invention will be described below with reference to the drawings. first,
Figure 1 shows a lactance resolver (
FIG. 2 is an explanatory diagram of a resolver (hereinafter simply referred to as a resolver).

As shown in the figure {; on the inner circumference of the stator 3 of the resolver 1 {
Above: Four exciting salient poles A, B, C, at equal intervals of 90 degrees.
D is provided, and excitation salient poles A and C and excitation salient poles B and C, which face each other in the radial direction, form a pair (hereinafter, excitation salient pole pair A and C will be referred to as ACa1 excitation salient pole pair). B and D are referred to as BD phase). To the excitation salient pole pair A and C (
Above, the first winding LACI and the second winding AC2 are wound differentially. The excitation salient pole pair B and D are wound one above. The third winding L BD 1 and the fourth winding LBD2 are differentially wound. It is wrapped.

It has a cylindrical shape and is arranged eccentrically with respect to the rotation axis Q of the motor (not shown) so that it rotates integrally with the rotation axis ○. When the rotor 5 rotates, the distance between the rotor 5 and the exciting salient poles of the stator 3 changes as the rotor 5 rotates.

As shown in Figure 2, 1:, the first winding L AC 1 and the third
The sine wave signal V STD output from the reference signal generator ○SC is added to the winding L BD 1.
^C2 and the fourth winding LBD2 it. A signal in which the sine wave is inverted by the inverting amplifier OP (the phase differs from the sine wave signal by π) 'INV is added to each excitation phase A, B
, C, and D are excited. Then, the midpoint NAC between the first winding LACI and the second winding LAC2 of the AC phase, and BD
Phase 3rd winding LBDI and 4th winding LBD2 midpoint NBD
A composite signal VNAC and VNBD of the signal V STD and the inverted signal VINV, respectively, are output to an R/D converter (resolver/digital converter) RDC as rotation angle signal generating means.

R/D converter RDCf;t, two input signals V
The rotation angle θ of the rotor 5 is detected from the NAC and VNBD, and the rotation angle θ and the digital value θdi of the rotation angle are
A multiplier RM and a synchronous rectifier DET that output a deviation signal (voltage) according to the deviation (θ - θdig) from g, an integrator IG that integrates the deviation signal, and an oscillation frequency according to the output of the integrator IG. a voltage controlled oscillator vC○ that varies the
A counter CNT feeds back a correction signal to the multiplier RM so that the deviation becomes zero (θ=θdig) based on the output of the voltage controlled oscillator vC○, and outputs the rotation angle θ of the rotor 5 as a digital signal θd1g. (The R/D converter is a well-known one, such as the AD2S8 manufactured by Analog Devices Inc.
0, DOC Corporation's RDC-17210, etc. are known).

In this embodiment, the reference signal generator ○SC and the inverting amplifier OP correspond to the excitation means.

next]:. Excitation signal VSTD, VINV midpoint N
The relationship between the output signals VNAC and VNBD from AC and NBD will be explained.

The sine wave signal V STD applied to the first winding LACI and the third winding LBDI, V STD= V OX sinωt The inverted signal V INV applied to the second winding LAC2 and fourth winding LBD2, V INV= - V OX sinωt each winding LAC
If the inductances of I, LAC2, LBDI, and LBD2 are Q^, QC, QB, and QD, they are expressed by the following equation based on the potential VNAC+ of the midpoint NAC of the AC phase.

1 Inductance QA. l2ct & As shown in Fig. 3, the inductance is the composite component of the 1:% offset QO and the periodic change due to the rotation of the rotor 5, 11a(θ) (θ(upper). However, Qro is the mechanical structure of the stator 3 and rotor 5,
It is a constant determined by the material, and each winding LACI, L
AC2, LBDI, and LBD2 are almost equal.

QA=Q(θ)=QrJ+Qa(.θ)QC:Q(θ
1π) = Q O+(l a (θ−π)Qa(θ
) by trigonometric functions (f, Q A= Q O+ Q
aX sinθ−(2)Q C= Q O+ Q a
X sin (θ−π)=l20 12aXsinθ
- (3) By substituting equations (2) and (3) into equation (1), the following equation is obtained.

V N AC= (-Q a/ Q O) X sin
θX sinωt-(4) Similarly, V N BD= (-Q a/Q O) X cos
θX sin ωt −·(5) is obtained.

(4) From formula (5), the output VNACI1 input signal from the midpoint NAC of the AC phase (V STD = V OX
sinωt ) Te, change in inductance (sin
θ), which is the output from the midpoint NBD of the BD phase VNBDI's output from the midpoint NAC of the AC phase VNA
It can be seen that this is a signal whose phase is delayed by π/2 from that of C. These signals VNAC% VNBDI; J:R/DDn/(
By performing feedback control so that the deviation (θ - θdig) between the rotation angle θ input to the rotor RDC and the digital value θdg of the rotation angle becomes zero, an accurate rotor 5
A rotation angle signal θdig is obtained.

As described above, since the rotation angle θ of the rotor 5 can be detected without using the secondary winding on the resolver 11 of this embodiment, movable parts such as brushes and rotary transformers are not required, and accordingly, the device This not only improves the reliability of the device, but also allows the device to be made smaller and lighter. Also, since no current detection resistor is used, there is no temperature drift. In other words, with conventional resolvers that use a current detection resistor instead of a secondary winding (although there is a problem that the characteristics of the detection signal change due to heat generation of the companion resistor and changes in ambient temperature),
In this embodiment, the output signal VNAC,
VNBD does not change.

In this example, the digital rotation angle signal θd1g was created from the analog signal output from the resolver 1 from the R/D converter RDC2, but in addition to this, the phase difference between the excitation signal and the output signal was calculated using a clock pulse. The rotation angle detection signal may be obtained by a circuit using a well-known phase control method that counts at ac= V OX co
sωt, and the second winding LAC2 has its inverted signal V in
ac = - V OX cos ωt, and the third winding LBD1 of the BD phase has a sine wave signal V bd = V OX sin
ωt is the inverted signal V i of 1 to the fourth winding LBD2.
nbd=-V OX sinωt is not added AC
Output VNACI from phase midpoint NAC; ILV N AC
= (Q a/Q O) XcosθXsinωt
Output from midpoint of 8D phase V N BDf yo V N BD
= (Q a/Q O) X sinθXcosw
It becomes t. Then, the differential amplifier ○P1 outputs the difference between these output voltages.

VNBD-VNAC= (Qa/QO)
X(sinθcosωt−cosθsinωt)=(
Q a/Q O)
= V OX sin ωt is a signal whose phase is shifted by the rotation angle θ of the rotor 5. By inputting this output signal into a well-known deviation counter and counting the phase difference θ using clock pulses, an accurate digital rotation angle signal can be obtained.

In this way, the present invention can accurately detect the rotation angle of the rotor 5 also by the phase control method.

In addition, in this embodiment, one friend is the first winding L1^C, the third winding LBD1, the second winding LAC2, and the fourth winding LBD2.
Different excitation signals were applied to each of the first winding L
Add excitation signal only to I AC and third winding LBDI,
One ends of the second winding LAC2 and the fourth winding LBD2 may be grounded.

In this case, as shown in Figure 5, the first AC phase
Wind the wire and apply a sine wave signal to C1 V ac = V OX si
nωt, second winding LAC2 niha cosine wave signal V bd=
When V OX cos ωt is added, the output signal V OUT= sin (ωt−θ
). By inputting this output into a well-known deviation counter and counting the phase difference θ using clock pulses, an accurate digital rotation angle signal can be obtained.

When this one-sided excitation is used, an inverting amplifier is not required, which simplifies the device configuration.

Furthermore, in this embodiment, the signals applied to the first winding LIAC, the third winding LBDI, the second winding LAC2, and the fourth winding LBD2 have a phase difference of π,
Of course, the phase difference is not limited to π.

Further, in this embodiment, the rotor 5 is the resolver 1 in which a cylindrical member is arranged eccentrically, but it may also be a multipolar resolver in which the rotor is shaped into a tooth shape. In this case, since the inductance change period becomes faster, the frequency of the excitation signal may be increased.

[Effects of the invention As explained above 1:. According to the present invention, since a signal having as variables an AC signal that excites each salient pole of each excitation salient pole pair and a change in the inductance of the winding is extracted from the midpoint of the winding, the secondary winding and It is possible to accurately detect one rotation angle without using a current detection signal. Therefore, the device can be made smaller and lighter, and detection errors due to temperature changes can be eliminated.

[Brief explanation of drawings]

Figure 1 is an explanation of the resolver of the embodiment. Figure 2 is the electric circuit of the resolver. Figure 3 is an explanation of changes in inductance. Figure 4 is the electric circuit of another example. Figure 5 is the electric circuit of the resolver. FIG. 2 is an electrical circuit diagram showing an example. 1... Reluctance type resolver 3... Stator 5... Rotor A, B, C, D... Exciting salient pole LACI・
...First winding LAC2...Second winding LB
DI... Volume 3! i LBD2...Fourth winding ○SC...Reference signal generator RDC...R/D converter

Claims (1)

[Scope of Claims] A stator having a plurality of excitation salient pole pairs each having windings wound differentially; a rotor that changes the inductance of the winding of each of the excitation salient pole pairs according to the rotation angle; A rotation angle detection device comprising: excitation means for exciting each of the two salient poles in each of the excitation salient pole pairs with alternating current signals having mutually different phases; A rotation angle detection device comprising: rotation angle signal generation means for generating a rotor rotation angle signal based on a composite signal of the two output AC output signals.