JP7632153B2 - Method for adjusting a differential resolver and a differential resolver - Google Patents

Description

This disclosure relates to a method for adjusting a differential resolver and a differential resolver.

A differential resolver is known that is suitable for preventing erroneous detection by a rotation sensor when a moment load is applied (for example, Patent Document 1).

JP 2008-216073 A

In a differential resolver that detects position based on the difference between differential signals of multiple phases, if there is variation in the signal output from the excitation winding, the position detection accuracy may decrease.

The present disclosure has been made in consideration of the above problems, and aims to provide a differential resolver and an adjustment method for a differential resolver that can suppress deterioration in position detection accuracy due to variations in the signal output from the excitation winding.

In order to achieve the above object, an adjustment method for a differential resolver according to one embodiment of the present disclosure is a method for detecting a current change due to a reluctance change when AC power is supplied to an excitation winding of each phase based on a difference signal between a first output signal of N phases shifted by 360 [deg]/N (N is an integer of 2 or more) depending on the position of the resolver rotor relative to the resolver stator, and a second output signal of a reverse phase inverted from the first output signal for each phase, in which the reluctance between the resolver rotor and the resolver stator changes depending on the position of the resolver rotor relative to the resolver stator, and the method includes a first step of adjusting the signal obtained by adding up the first output signals of N phases so that the AC component of the signal is approximately zero, and a second step of adjusting the signal obtained by adding up the first output signal and the second output signal after the first step so that the AC component of the signal is approximately zero.

The above configuration makes it possible to suppress deterioration in position detection accuracy due to variations in the signal output from the excitation winding.

As a desirable aspect of the method for adjusting a differential resolver, in the first step, it is preferable to ground the input terminal of the second output signal of the differential amplifier circuit that outputs the difference signal between the first output signal and the second output signal, and add the N-phase first output signal.

This makes it possible to absorb variations caused by the differential amplifier circuit.

In order to achieve the above object, a differential resolver according to one aspect of the present disclosure is a differential resolver in which the reluctance between a resolver rotor and a resolver stator changes depending on the position of the resolver rotor, and detects a current change due to a reluctance change when AC power is supplied to an excitation winding of each phase based on a difference signal between a first output signal of N phases shifted by 360 [deg]/N (N is an integer of 2 or more) depending on the position of the resolver rotor relative to the resolver stator, and a second output signal of a reverse phase inverted from the first output signal for each phase, and a plurality of excitation windings are connected in series to a single-phase AC power source and are grounded via a resistor, the first output signal is output from a connection point between the plurality of excitation windings and the resistor, a plurality of excitation windings are connected in series to the single-phase AC power source and are grounded via a resistor, the second output signal is output from a connection point between the plurality of excitation windings and the resistor, and at least 2N-1 of the 2N resistors are variable resistors.

The above configuration can suppress deterioration in position detection accuracy due to variations in the signal output from the excitation winding. It can also make adjustment work more efficient.

A desirable aspect of the differential resolver is that all 2N resistors are variable resistors.

A preferred embodiment of the differential resolver is equipped with a differential amplifier circuit that outputs a difference signal between the first output signal and the second output signal.

A preferred embodiment of the differential resolver may further include a switch circuit that grounds the input terminal of the second output signal of the differential amplifier circuit.

The present disclosure provides a method for adjusting a differential resolver and a differential resolver that can suppress deterioration in position detection accuracy due to variations in the signal output from the excitation winding.

FIG. 1 is a vertical cross-sectional view of a motor to which a differential resolver according to a first embodiment is applied. FIG. 2 is a cross-sectional view of the differential resolver according to the first embodiment. FIG. 3 is a circuit diagram showing a circuit configuration of the differential resolver according to the first embodiment. FIG. 4A is a diagram showing an example of the waveform of the first A-phase output signal. FIG. 4B is a diagram showing an example of the waveform of the first B-phase output signal. FIG. 4C is a diagram showing an example of the waveform of the first C-phase output signal. FIG. 5A is a diagram illustrating a first procedure of the adjustment method for the differential resolver according to the first embodiment. FIG. 5B is a diagram illustrating a first procedure of the adjustment method for the differential resolver according to the first embodiment. FIG. 6A is a diagram illustrating a second procedure of the adjustment method for the differential resolver according to the first embodiment. FIG. 6B is a diagram illustrating a second procedure of the adjustment method for the differential resolver according to the first embodiment. FIG. 7 is a circuit diagram showing a circuit configuration of a differential resolver according to the second embodiment.

Below, a detailed description of a form for carrying out the invention (hereinafter, referred to as an embodiment) will be given with reference to the drawings. Note that the present disclosure is not limited to the following embodiment. Furthermore, the components in the following embodiment include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiment can be combined as appropriate.

(Embodiment 1)
Fig. 1 is a vertical cross-sectional view of a motor to which a differential resolver according to embodiment 1 is applied. As shown in Fig. 1, the motor 100 is configured to include a stator 22 which is a stationary part, a rotor 12 which is a rotor, a cross roller bearing 14 which is interposed between the rotor 12 and the stator 22 and rotatably supports the rotor 12, a motor section 16 which applies a rotational torque to the rotor 12, and a resolver 30 which detects the rotational angular position of the rotor 12. Here, the resolver 30, the cross roller bearing 14, and the motor section 16 are arranged on the same radial plane in that order from the radially inner side.

The stator 22 is formed with an annular inner wall body 22a that protrudes axially upward (upward in FIG. 1), and an annular outer wall body 22b that protrudes axially upward is formed radially outward from the inner wall body 22a. On the other hand, the rotor 12 is formed with an annular inner wall body 12a that protrudes axially downward (downward in FIG. 1), and an annular outer wall body 12b that protrudes axially downward is formed radially outward from the inner wall body 12a. The stator 22 and the rotor 12 are arranged straddling each other such that the inner wall body 22a of the stator 22 is located between the inner wall body 12a and the outer wall body 12b of the rotor 12, and the outer wall body 12b of the rotor 12 is located between the inner wall body 22a and the outer wall body 22b of the stator 22.

The cross roller bearing 14 is composed of an inner ring 14a, an outer ring 14b, and multiple cross rollers (rollers) 14c that are rotatably arranged between the inner ring 14a and the outer ring 14b. The cross rollers 14c are approximately circular with a diameter slightly larger than their length, and the even-numbered rotation axes on the orbit and the odd-numbered rotation axes on the orbit are inclined at 90° to each other.

The inner ring 14a is fixed by gluing its lower surface to the upper surface of the inner wall body 22a of the stator 22. The outer ring 14b is fixed by gluing its upper surface to the lower surface of the outer wall body 12b of the rotor 12.

The stator 22 is fixed to the fixed plate 24 by bolts 24a, and the rotor 12 is fitted to the outer circumferential surface of the output shaft.

The motor section 16 is composed of a permanent magnet 16a and a coil 16b arranged facing the permanent magnet 16a at a predetermined distance. The permanent magnet 16a is directly fixed to the outer peripheral surface of the outer ring 14b by being glued to the outer peripheral surface of the outer ring 14b without using any intermediate member. Meanwhile, the coil 16b is attached to the outer wall body 22b of the stator 22 by a bolt 16c.

The resolver 30 detects the position of the motor 100. The resolver 30 is an outer rotor type differential resolver that includes a resolver rotor 18 made of a hollow annular laminated core, and a resolver stator 20 that is arranged facing the resolver rotor 18 at a predetermined distance and made of an annular laminated core with multiple stator poles formed at equal intervals in the circumferential direction.

The resolver rotors 18 of the two resolvers 30 are placed at a small distance via rotor spacers 42 and are attached to the outer circumferential surface of the inner wall body 12a of the rotor 12 by bolts 18a. On the other hand, the resolver stators 20 of the two resolvers 30 are directly fixed to the inner circumferential surface of the inner ring 14a by being glued to the inner circumferential surface of the inner ring 14a without any intervening members.

By passing current through the coil 16b, the rotor 12 and resolver rotor 18 rotate together, and the resolver stator 20 detects reactance changes, and a controller (not shown) controls the rotation speed and positioning.

Figure 2 is a cross-sectional view of a differential resolver according to the first embodiment. Figure 3 is a circuit diagram showing the circuit configuration of the differential resolver according to the first embodiment.

On the inner peripheral surface of the resolver stator 20, as shown in Fig. 2, N-phase, for example, 18-pole, three-phase first magnetic poles A11-A16, B11-B16, C11-C16 are formed at a predetermined interval in that order, protruding in the radial direction, and 18-pole, three-phase second magnetic poles A21-A26, B21-B26, C21-C26 are formed at the intermediate positions of the first magnetic poles A11-A16, B11-B16, C11-C16, respectively, and these magnetic poles are arranged in the order of A11-21-B11-A21-C11-B21-A12-C22-... Each magnetic pole A11-C26 has three teeth TS1-TS3 formed on the end face on the inner peripheral surface side, and one excitation winding LA11-LC26 is wound in the center. Therefore, the magnetic poles at 180 degrees are in phase with each other.

The resolver rotor 18 has 150 slot teeth TR formed at equal intervals on its outer circumferential surface. Here, the pitch of the slot teeth TR of the resolver rotor 18 is such that, for example, if three adjacent teeth TR of the resolver rotor 18 coincide with the teeth TS1 to TS3 of the magnetic pole A11 of the resolver stator 20, the teeth TS1 to TS3 of the adjacent magnetic pole C21 are mechanically shifted in phase by 1/36 pitch relative to the slot teeth TR of the resolver rotor 18.

The excitation windings LA11 to LC26 of the magnetic poles A11 to C26 are connected in series with the excitation windings Li11 to Li16 of the first magnetic poles i11 to i16 (i=A, B, C) as shown in FIG. 3, so that the excitation windings LA11 to LC11 are connected to the single-phase AC power supply 63, and the excitation windings LA16 to LC16 are grounded via resistors RA1 to RC1, while the excitation windings Li21 to Li26 of the remaining second magnetic poles i21 to i26 are connected in series with the excitation windings LA21 to LC21 similarly connected to the single-phase AC power supply 63, and the excitation windings LA26 to LC26 are grounded via resistors RA2 to RC2. In this embodiment, the resistors RA1 to RC1 and RA2 to RC2 are variable resistors for signal adjustment, which will be described later.

The connection points between the excitation windings LA16-LC16 and LA26-LC26 and the resistors RA1-RC1 and RA2-RC2 are connected to output terminals TA1, TB1, and TC1, which output a first A-phase output signal A1, a first B-phase output signal B1, and a first C-phase output signal C1 in response to current changes due to reluctance changes between each magnetic pole and the slot teeth TR of the resolver rotor 18, and output terminals TA2, TB2, and TC2, which output a second A-phase output signal A2, a second B-phase output signal B2, and a second C-phase output signal C2. These are connected to three differential amplifier circuits 65A, 65B, and 65C, which are composed of operational amplifiers.

Each of the differential amplifier circuits 65A, 65B, and 65C has an operational amplifier OP whose non-inverting input side is connected to the output terminal TA1 via a resistor RI1 and grounded via a resistor RE, whose inverting input side is connected to the output terminals TA2, TB2, and TB2 via a resistor RI2, and a feedback resistor RF is inserted between the inverting input side and the output side. An output terminal TA is provided for outputting a difference signal between the first A-phase output signal A1 and the second A-phase output signal A2 input to the differential amplifier circuit 65A, an output terminal TB is provided for outputting a difference signal between the first B-phase output signal B1 and the second B-phase output signal B2 input to the differential amplifier circuit 65B, and an output terminal TC is provided for outputting a difference signal between the first C-phase output signal C1 and the second C-phase output signal C2 input to the differential amplifier circuit 65C.

The three-phase AC voltages corresponding to the excitation currents output from these differential amplifier circuits 65A, 65B, and 65C are supplied to a phase conversion circuit 66 that converts three phases into two phases, and the two-phase signal output from the phase conversion circuit 66 is supplied to a signal processing circuit 67.

Figure 4A is a diagram showing an example of the waveform of the first A-phase output signal. Figure 4B is a diagram showing an example of the waveform of the first B-phase output signal. Figure 4C is a diagram showing an example of the waveform of the first C-phase output signal.

4A, 4B, and 4C, the first i (i=A, B, C) phase output signal i1 is a waveform in which the AC waveform of the single-phase AC power supply 63 shown by the solid line is superimposed on an approximately sine wave signal (AC signal) corresponding to the current change due to the reluctance change between each magnetic pole and the slot teeth TR of the resolver rotor 18. Here, the approximately sine wave signal specifically has a waveform shape that closely resembles an ideal sine waveform, for example, when the motor 100 is rotating at a constant speed. The approximately sine wave signal appears as an envelope of the AC waveform of the single-phase AC power supply 63 shown by the solid line. In addition, the first B phase output signal B1 is a signal that is delayed by 120 [deg] of the approximately sine wave signal with respect to the first A phase output signal A1. In addition, the first C phase output signal C1 is a signal that is delayed by 240 [deg] of the approximately sine wave signal with respect to the first A phase output signal A1. That is, the first i-phase output signal i1 (i=A, B, C) is shifted by 360[deg]/3 (=120[deg]) depending on the position of the resolver rotor 18 relative to the resolver stator 20.

On the other hand, the second i-phase (i=A, B, C) output signal i2 is an inverted phase signal of the approximately sine wave signal of the first i-phase output signal superimposed with the AC waveform of the single-phase AC power supply 63. As a result, the second B-phase output signal B2 is an approximately sine wave signal delayed by 120 degrees from the second A-phase output signal A2. Also, the second C-phase output signal C2 is an approximately sine wave signal delayed by 240 degrees from the second A-phase output signal A2.

If variations occur in the approximately sine wave signals of the first phase A output signal A1, the first phase B output signal B1, the first phase C output signal C1, the second phase A output signal A2, the second phase B output signal B2, and the second phase C output signal C2, the position detection accuracy may be reduced. Causes of variations in the approximately sine wave signals of the first phase A output signal A1, the first phase B output signal B1, the first phase C output signal C1, the second phase A output signal A2, the second phase B output signal B2, and the second phase C output signal C2 include, for example, variations in each excitation winding and variations in each resistor of the differential amplifier circuits 65A, 65B, and 65C.

In this embodiment, by adjusting the variable resistors RA1 to RC1 and RA2 to RC2 used for signal adjustment, the variation in the approximately sinusoidal signals of the first A-phase output signal A1, the first B-phase output signal B1, the first C-phase output signal C1, the second A-phase output signal A2, the second B-phase output signal B2, and the second C-phase output signal C2 is suppressed, thereby improving the position detection accuracy. The adjustment method for the differential resolver according to the first embodiment is described below.

Figures 5A and 5B are diagrams illustrating the first step of the method for adjusting a differential resolver according to embodiment 1.

In this embodiment, first, the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 are adjusted. The first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 can be expressed by the following equations (1), (2), and (3), respectively. In the following equations (1), (2), and (3), A indicates the DC component of the first A-phase output signal A1, B indicates the DC component of the first B-phase output signal B1, and C indicates the DC component of the first C-phase output signal C1.

A1=(A+sinθ)×sinωt...(1)

B1={B+sin(θ-120)}×sinωt...(2)

C1={C+sin(θ-240)}×sinωt...(3)

The DC component A of the first A-phase output signal A1 can be adjusted by resistor RA1. The DC component B of the first B-phase output signal B1 can be adjusted by resistor RB1. The DC component C of the first C-phase output signal C1 can be adjusted by resistor RC1.

When the DC component A of the first A-phase output signal A1, the DC component B of the first B-phase output signal B1, and the DC component C of the first C-phase output signal C1 satisfy the following formula (4), the following formula (5) is established, and as shown in FIG. 5A, the approximately sinusoidal signal component of the signal obtained by adding the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 becomes zero.

A=B=C...(4)

A1+B1+C1=0...(5)

If the DC component A of the first A-phase output signal A1, the DC component B of the first B-phase output signal B1, and the DC component C of the first C-phase output signal C1 do not satisfy the above formula (4), the following formula (6) is satisfied, and as shown in Figure 5B, an approximately sinusoidal signal appears in the signal obtained by adding the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1.

A1+B1+C1≠0...(6)

In the first step of the adjustment method for the differential resolver according to the first embodiment, the output terminals TA2, TB2, and TC2 are grounded. As a result, the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 are output to the output terminals TA, TB, and TC, respectively. Then, the resistors RA1, RB1, and RC1 are adjusted so that the approximately sine wave signal (AC signal) appearing in the envelope of the signal obtained by adding the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 output from the output terminals TA, TB, and TC is within a predetermined range Δv1. More preferably, the resistors RA1, RB1, and RC1 are adjusted so that the approximately sine wave signal (AC signal) appearing in the envelope of the signal obtained by adding the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 is approximately zero.

In FIG. 3, an example is shown in which the switch circuits SWA, SWB, and SWC that ground the output terminals TA2, TB2, and TC2 are provided in the resolver 30, but this is not limiting, and the output terminals TA2, TB2, and TC2 may be grounded outside the resolver 30, such as on an adjustment jig connected to the output terminals TA2, TB2, and TC2.

Figures 6A and 6B are diagrams illustrating the second step of the method for adjusting a differential resolver according to embodiment 1.

In this embodiment, following the first step, adjustments are made to the second A-phase output signal A2, the second B-phase output signal B2, and the second C-phase output signal C2.

The approximately sine wave signals appearing in the envelopes of the second A-phase output signal A2, the second B-phase output signal B2, and the second C-phase output signal C2 are inverted phase signals relative to the approximately sine wave signals appearing in the envelopes of the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1, respectively.

The DC component A' of the second A-phase output signal A2 can be adjusted by resistor RA2. The DC component B' of the second B-phase output signal B2 can be adjusted by resistor RB2. The DC component C' of the second C-phase output signal C2 can be adjusted by resistor RC2.

When the DC component A of the first A-phase output signal A1 and the DC component A' of the second A-phase output signal A2 satisfy the following formula (7), the following formula (8) is established, and as shown in FIG. 6A, the approximately sinusoidal signal component of the signal obtained by adding the first A-phase output signal A1 and the second A-phase output signal A2 becomes zero.

A=A'...(7)

A1+A2=0...(8)

When the DC component A of the first A-phase output signal A1 and the DC component A' of the second A-phase output signal A2 do not satisfy the above formula (7), the following formula (9) is satisfied, and as shown in FIG. 6B, an approximately sinusoidal signal appears in the signal obtained by adding the first A-phase output signal A1 and the second A-phase output signal A2.

A1+A2≠0...(9)

In the second step of the method for adjusting the differential resolver according to the first embodiment, the resistor RA2 is adjusted so that the approximately sinusoidal signal (AC signal) appearing in the envelope of the signal obtained by adding the first A-phase output signal A1 output from the output terminal TA1 and the second A-phase output signal A2 output from the output terminal TA2 is within a predetermined range Δv2. More preferably, the resistor RA2 is adjusted so that the approximately sinusoidal signal (AC signal) appearing in the envelope of the signal obtained by adding the first A-phase output signal A1 and the second A-phase output signal A2 is approximately zero.

In the second step of the adjustment method for the differential resolver according to the first embodiment, the resistor RB2 is adjusted so that the approximately sine wave signal (AC signal) appearing in the envelope of the signal obtained by adding the first B-phase output signal B1 output from the output terminal TB1 and the second B-phase output signal B2 output from the output terminal TB2 is within a predetermined range Δv2. More preferably, the resistor RB2 is adjusted so that the approximately sine wave signal (AC signal) appearing in the envelope of the signal obtained by adding the first B-phase output signal B1 and the second B-phase output signal B2 is approximately zero.

In the second step of the adjustment method for the differential resolver according to the first embodiment, the resistor RC2 is adjusted so that the approximately sinusoidal signal (AC signal) appearing in the envelope of the signal obtained by adding the first C-phase output signal C1 output from the output terminal TC1 and the second C-phase output signal C2 output from the output terminal TC2 is within a predetermined range Δv2. More preferably, the resistor RC2 is adjusted so that the approximately sinusoidal signal (AC signal) appearing in the envelope of the signal obtained by adding the first C-phase output signal C1 and the second C-phase output signal C2 is approximately zero.

The first and second steps of the adjustment method for the differential resolver according to the first embodiment described above can suppress the deterioration of position detection accuracy caused by variations in the signal output from the excitation winding.

(Embodiment 2)
7 is a circuit diagram showing a circuit configuration of a differential resolver according to embodiment 2. In this embodiment, of the resistors RA1 to RC1 and the resistors RA2 to RC2, the resistor RB1 is a fixed resistor.

In the first step of the adjustment method for the differential resolver according to this embodiment, output terminals TA2, TB2, and TC2 are grounded, and resistors RA1 and RC1 are adjusted so that the approximately sinusoidal signal appearing in the envelope of the signal obtained by adding together the first A-phase output signal A1, the first B-phase output signal B1, and the first C-phase output signal C1 output from output terminals TA, TB, and TC is within a predetermined range Δv1. This makes it possible to make the adjustment work more efficient.

In the above embodiment, the first i-phase output signal i1 (i = A, B, C) is shifted by 360 [deg] / 3 (= 120 [deg]) depending on the position of the resolver rotor 18 relative to the resolver stator 20, and the second i-phase output signal i2 (i = A, B, C) is an opposite-phase signal whose phase is inverted with respect to the first i-phase output signal i1. However, the present invention is not limited to this. It is also possible to apply the present invention to a mode in which a current change due to a reluctance change when AC power is supplied to the excitation winding of each phase is detected based on a difference signal between an N-phase first output signal shifted by 360 [deg] / N (N is an integer of 2 or more) and a second output signal whose phase is inverted with respect to the first output signal for each phase.

The figures used above are conceptual diagrams for providing a qualitative explanation of the present disclosure, and are not intended to be limiting. The above-described embodiment is an example of a suitable implementation of the present disclosure, but is not intended to be limiting, and various modifications may be made without departing from the spirit of the present disclosure.

30 Resolver 63 Single-phase AC power supply 65A, 65B, 65C Differential amplifier circuit 66 Phase conversion circuit 67 Signal processing circuit A1 1st A-phase output signal A2 2nd A-phase output signal B1 1st B-phase output signal B2 2nd B-phase output signal C1 1st C-phase output signal C2 2nd C-phase output signal LA11 to LA16, LA21 to LA26, LB11 to LB16, LB21 to LB26, LC11 to LC16, LC21 to LC26 Excitation winding RA1, RB1, RC1, RA2, RB2, RC2 Resistors SWA, SWB, SWC Switch circuit TA, TB, TC Output terminals TA1, TB1, TC1 Output terminals TA2, TB2, TC2 Output terminals 100 Motor

Claims (7)

A method for adjusting a differential resolver, the method comprising: detecting a current change caused by a reluctance change between a resolver rotor and a resolver stator depending on a position of the resolver rotor, based on a difference signal between first output signals of N phases shifted by 360 [deg]/N (N is an integer of 2 or more) depending on a position of the resolver rotor with respect to the resolver stator, and a second output signal of a reverse phase inverted from the first output signal for each phase, when AC power is supplied to an excitation winding of each phase, the method comprising:
a first step of adjusting an AC component of a signal obtained by adding up the first output signals of N phases so that the AC component becomes approximately zero;
a second step of adjusting, for each phase after the first step, N signals obtained by adding the first output signal and the second output signal so that each of the AC components becomes approximately zero;
having
How to adjust a differential resolver. In the first step, an input terminal of the second output signal of a differential amplifier circuit that outputs a difference signal between the first output signal and the second output signal is grounded, and the first output signals of N phases are added.
2. The method for adjusting a differential resolver according to claim 1. The differential resolver includes:
a plurality of excitation windings are connected in series to a single-phase AC power supply and are grounded via a first resistor, and the first output signal is output from a connection point between the plurality of excitation windings and the first resistor;
a plurality of excitation windings are connected in series to the single-phase AC power supply and are grounded via a second resistor, and the second output signal is output from a connection point between the plurality of excitation windings and the second resistor;
In the first step, the first resistor is adjusted so that an AC component of a signal obtained by adding up the first output signals of N phases becomes approximately zero;
In the second step, the second resistor is adjusted so that AC components of N signals obtained by adding the first output signal and the second output signal for each phase are each approximately zero.
3. A method for adjusting a differential resolver according to claim 1 or 2. In the differential resolver, the N first resistors and the N second resistors are variable resistors.
The method for adjusting a differential resolver according to claim 3 . In the differential resolver, N-1 first resistors and N second resistors are variable resistors.
The method for adjusting a differential resolver according to claim 3 . The differential resolver is adjusted by the adjustment method according to any one of claims 1 to 5.
Differential resolver. a differential resolver in which a reluctance between a resolver rotor and a resolver stator changes depending on a position of the resolver rotor, and a current change caused by a reluctance change when AC power is supplied to an excitation winding of each phase is detected based on a difference signal between first output signals of N phases shifted by 360 [deg]/N (N is an integer of 2 or more) depending on a position of the resolver rotor with respect to the resolver stator, and a second output signal of an opposite phase that is inverted in phase with respect to the first output signal for each phase,
a plurality of excitation windings are connected in series to a single-phase AC power supply and are grounded via a resistor, and the first output signal is output from a connection point between the plurality of excitation windings and the resistor;
a plurality of excitation windings are connected in series to the single-phase AC power supply and are grounded via a resistor, and the second output signal is output from a connection point between the plurality of excitation windings and the resistor;
Among the 2N resistors, at least 2N-1 resistors are variable resistors;
a differential amplifier circuit that outputs a difference signal between the first output signal and the second output signal;
a switch circuit that grounds an input terminal of the second output signal of the differential amplifier circuit;
Equipped with
Differential resolver.

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