JPS6333615A - Three-phase variable reluctance type resolver - Google Patents

Abstract

PURPOSE:To detect an angle accurately, by exciting two three-phase winding series circuits different in the array sequence with the same voltage. CONSTITUTION:In a three-phase variable reluctance type resolver 20, a series circuit 21 of three-phase windings (a), (b) and (c) is connected in parallel to a series circuit 22 of the windings (b), (c) and (a) arranged in the array sequence of being shifted by one phase. An arithmetic circuit 27 draws connection point potentials of circuits 21 and 22 at terminals 23-26 and performs a computation using operational amplifiers 28-31 to obtain a potential difference (b-c) corresponding to sintheta of a rotor angle theta and a potential difference (a-(b+c)/2) corresponding to costheta to be outputted to a resolver digital converter section 13. As an interphase potential is drawn by the series connection of the windings (a), (b) and (c), there is no deviation in the phase between a synchronous rectification signal obtained at a transmission circuit 11 for exciting the resolver 20 and signals to be fetched at terminals 23-26. This eliminates fluctuation of an output signal theta depending on angle.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a resolver that is a rotation amount (angle) detection sensor for a motor, machine tool, or various measuring devices, and particularly relates to a three-phase variable reluctance type resolver. It is.

[Conventional technology]

FIG. 2 is a partial structural diagram showing the structure of a three-phase variable reluctance resolver. This variable reluctance resolver has an inner and outer stator 1.2 each having an IEI winding part, and a rotor 3 having 150 salient poles arranged at equal intervals on both the inner and outer surfaces is disposed between them. has been done. A plurality of salient poles are also provided at various tips of the inner and outer stators 1.2, and when paying attention to the three adjacent poles (taking the outer stator 2 as an example, 2a, 2b, and 2C),
The relative positions of the salient poles provided at the various tips and the salient poles of the rotor 3 are shifted from each other. That is, FIG. 3 shows the positional relationship between the salient poles of the outer stator 2 and the salient poles of the rotor, and as shown in FIG. When matched, the salient pole of pole 2b and the salient pole of rotor 3 are offset by 120@ as shown in FIG.
The salient poles of C and the salient poles of rotor 3 are 2 as shown in the same figure (c).
There is a deviation of 40@.

FIG. 4 is a circuit diagram showing an angle detection device using a resolver having such a structure, and the resolver 10 is constructed by connecting resistors R in series to each of the various types a, b, and c of the stator. . The oscillation circuit (O
3C) When alternating current excitation at frequency f0 is performed at 11, the L portion of the various coils changes according to the rotation of the rotor, and the current flowing through the coils changes. When the current changes, voltage changes corresponding to various current changes appear at the three output terminals of the resolver 10, respectively. These signals, which are 120" out of phase with each other, are converted into two-phase signals with a 90" phase shift in a three-phase to two-phase conversion circuit 12, and finally converted into two-phase signals with a 90" phase shift. Extract the rotation angle θ of the rotor as a digital value.

In this way, in the conventional variable reluctance resolver,
Utilizing the fact that the current i changes due to various changes in L, the change is extracted as a voltage value iR.

Fig. 5 is a waveform diagram showing an example of a signal appearing at one of the output terminals of the resolver 10, and Fig. 6 is its vector diagram.As can be seen from this vector diagram, the current is delayed by the phase φ. . Therefore, in the RDC section 13, 03CII
The phase delay circuit 14 delays the signal from the signal by a phase amount corresponding to the delay angle φ to generate a synchronous rectification signal.

[Problem that the invention seeks to solve]

However, the phase φ of the detected current is not a fixed value but changes as L changes, that is, as the rotor position changes, and a phase shift occurs between the input carrier and the synchronous phase signal. It will happen. Such a phase shift is R
Since it acts to reduce the gain of the three internal phase discrimination in the DC section 1, its output voltage changes depending on the angular position of the rotor. That is, the output of the RDC section 13 is given fluctuations due to the rotation angle.

In addition, when using the output signal of the resolver IO, it is passed through the three-phase to two-phase conversion circuit 12 to generate a sine signal with a phase shift of 90°.
, a cos signal is obtained, but in the process of this three-phase two-phase conversion, it is necessary to remove the carrier bias component and create a signal as shown in Figure 7, but it is difficult to accurately remove the bias component. Very difficult.

[Means for solving problems]

The three-phase variable reluctance resolver of the present invention has been developed in view of the above problems, and includes a first circuit in which three-phase windings are connected in series, and a winding arrangement order that is different from that of the first circuit. The first circuit and the second circuit are connected in parallel so that AC excitation of the same potential can be performed, and the potential of the windings of each phase can be adjusted. This allows it to be taken out as output.

[Effect]

Since the three-phase coils are connected in series, the magnitude of the current flowing through each coil is the same, and the voltage drop that occurs in each coil varies depending on the L portion of the coil, but the total of the three phases is always equal to the excitation vAt pressure. Therefore, at each output terminal, a change in potential can be obtained that accurately corresponds to a change by L in each phase.

〔Example〕

Hereinafter, the present invention will be described in detail along with examples.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and the same or corresponding parts as in FIG. 4 are given the same reference numerals.

The three-phase variable reluctance resolver 20 of this embodiment has a first circuit 21 in which three-phase windings a, b, and c are connected in series, and the windings are arranged in one order relative to the first circuit 21. The winding order is shifted by one phase.

c and a second circuit 22. The first circuit 21 and the second circuit 22 are connected in parallel so that AC excitation at the same potential can be performed by 03CII. Then, the potential between the a-phase winding and the sub-phase winding and the potential between the b-phase winding and the C-phase winding of the first circuit 21 can be taken out from the output terminals 23 and 26, respectively.

Further, the potential between the b-phase winding and the C-phase winding of the second circuit 22 and the potential between the C-phase winding and the a
The potential between the phase windings can be extracted.

In this way, since the three-phase coils are connected in series, the magnitude of the current flowing through each coil is all equal. Also,
The voltage drop generated in each coil varies depending on the L portion of the coil, but the sum of the three phases is always equal to the excitation voltage. Therefore, at the output terminals 23 to 26, the potential changes according to the change of L in each phase.

The voltage appearing at the output terminals 23 to 26 is as follows: where the voltage drop in the A-phase winding is a, the voltage drop in the B-phase winding is C, and the voltage drop in the C-phase winding is C. (b+c), respectively.
(c+a), a, c. These four types of signals are input to the arithmetic circuit 27, and finally (b-c) and (a-(b+)
c)/2) is obtained. The inside of the arithmetic circuit 27 is composed of general arithmetic means using operational amplifiers 28 to 31, and first, the potential difference (a - b) between the terminals 23 and 24 is calculated.
) and the potential difference (c-a) between the terminals 25 and 26. Then, (b-c) and (a-(b+c)/2) are obtained using operational amplifiers 30 and 31. The output −(b−c) of the arithmetic circuit 27 corresponds to sin θ, and (a−(b+
c)/2) corresponds to cos θ. These two signals are input to a well-known RDC unit 13, and the value of θ is extracted as a digital value. The output of the arithmetic circuit 27 (b-c) and (a-
The phase of the carrier component of (b+c)/2) is 03CII
Since the phase of the output f0 coincides with that of the output f0, a phase delay circuit is not required.

〔Effect of the invention〕

As explained above, according to the three-phase variable reluctance resolver of the present invention, the change in rotor angle is not taken out by the current change in the coil as in the conventional case, but by the potential between the phases. There is no phase shift with the synchronous rectification signal due to current phase delay. Therefore, the output of the RDC is not affected by phase changes, and a phase delay circuit is not required. Further, the bias component of the carrier can be easily canceled and no gain adjustment is required. Furthermore, since the bridge circuit is composed of various coils, there is an advantage that the change per pole is twice that of the conventional method.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a partial structural diagram showing the structure of a three-phase variable reluctance resolver,
Fig. 3 is an explanatory diagram showing the relative positional relationship between the salient poles of the rotor and the salient poles of the stator, Fig. 4 is a circuit diagram of an angle detection device using a conventional three-phase variable reluctance resolver, and Fig. 5 is a diagram showing the relative positional relationship between the salient poles of the rotor and the stator.
Figure 6 is the resolver output waveform diagram, Figure 6 is its vector diagram,
FIG. 7 is an intermediate output waveform diagram of the device of FIG. 4. 20... Three-phase variable reluctance resolver, 21...
・First circuit, 22...Second circuit, 23-26...
・Output terminal.

Claims (1)

[Claims] It has a first circuit in which three-phase windings are connected in series, and a second circuit in which the arrangement order of the windings is shifted by one phase with respect to the first circuit. A three-phase variable reluctance resolver in which the two circuits are connected in parallel to perform alternating current excitation at the same potential, and the potential of the windings of each phase can be taken out as output.