JPS59126957A - Method and device for detecting rotating speed using resolver - Google Patents

Abstract

PURPOSE:To perform brushless detection of a rotating speed with high sensitivity by obtaining a rotating speed signal in accordance with the frequency difference of the two-frequency modulating signals outputted from two phases of output windings of a resolver. CONSTITUTION:An excitation signal is applied from a sine wave signal oscillator 2 to the excitation winding WX of a resolver 1. The 1st phase shifter S1 and the 2nd phase shifter S2 are connected to two phases of output windings Walpha, Wbeta of the resolver 1, and are further connected to waveform shaping circuits 7, 8. The outputs of the circuits 7, 8 are applied to frequency-voltage converters 9, 10, and the differential voltage of the respective converter is outputted from a differential amplifier 1 by which the signal proportional to the rotating speed is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a method and apparatus for detecting the rotational speed of a rotating machine using a resolver component.

In general, in speed control systems used for positioning control and constant cutting control in machine tools, speed detection is required to stabilize the control system and improve responsiveness. It is necessary to add a loop to the device to detect the entire rotational speed and control the speed, and conventionally a DC tacho generator has been used as the speed detector for this purpose. However, speed detectors that use brushes, such as those used in DC Quko generators, suffer from problems such as wear of the brushes and instability of the contact voltage between the brushes and the commutator pieces, as well as complicated maintenance of the control system and decreased reliability. There was a problem. There is a way to use an optical tacho generator as a brushless speed detector and convert its output pulse signal into p' torque by a frequency-voltage converter and use it for control, but this pulse signal Since there is a limit to the number of pulses, there is a limit to satisfactory control during low-speed operation. Therefore, speed detectors that use resolvers, which are highly reliable in terms of brushless electromagnetic detectors, have recently been used, but these are capable of detecting only one signal whose frequency changes in proportion to the rotational speed. However, since the speed detection sensitivity is low, the speed detection sensitivity is low.

The present invention applies an excitation signal to the excitation winding of a resolver having a one-phase excitation winding and a two-phase output winding, and synthesizes two output signals output from the two-phase output winding, A rotational speed detection method using a resolver that overcomes the above-mentioned drawbacks by obtaining two different frequency modulation signals and obtaining a rotational speed signal proportional to the rotational speed based on the frequency difference between the two frequency modulation signals, and This paper proposes a detection device.

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the drawings. In Fig. 1, 1 is a one-phase excitation winding W x 'k on the rotor, and two-phase output windings Wα, Wβ on the stator.
and the above excitation winding Wx
The rotor position is detected by the output signals of the output windings Wα and Wβ due to electromagnetic coupling between the output windings Wα and Wβ. Reference numeral 2 denotes a sine wave signal oscillator for causing an excitation i torrent to flow through the excitation winding Wx, and outputs an excitation voltage ef shown in the following equation (1).

ez = Ex sinωo t
-(1) Here, Ex is voltage amplitude, ωo-2πfO-,
fO is the excitation frequency. The resolver 1 receives the above excitation voltage eX through the excitation winding Wx, and outputs the following output signals e from the output windings Wα and Wβ, respectively. Or release an epk.

ea= El sinωOt −5in Oe
−(2)”I = EI sinωOj −cp
sθe 1= (3) Here, El is the voltage amplitude, and θe is the electrical angle of the rotor rotational angular velocity of the resolver 1. 3 and 5 are resistors with a resistance value R, 4 and 6 are capacitors with a capacitance C, the capacitor 4 and the resistor 3 are connected in series to form the first phase shifter 81, and the resistor 5 and the capacitor 6 are connected in series. They are connected in series to constitute a second phase shifter Sx'c. The output signal ea of the output winding Wα is applied to one end of each of the capacitor 4 and the resistor 5, and the entire output signal eβ of the output winding Wβ is applied to one end of each of the resistor 3 and the capacitor 6. Interconnection point P of capacitor 4 and resistor 3
The output voltage ea of the phase shifter 81 from I is applied to the waveform shaping circuit 7 for shaping into a square wave pulse signal, and the output voltage eb of the phase shifter S2 is applied to the interconnection point P2 of the resistor 5 and the capacitor 6. is similarly applied to the waveform shaping circuit 8.

There is a relationship R=1/ωOC between the resistance value R of the resistors 3 and 5 and the capacitance C of the capacitor 4°6.
Es1n (ωat soil θe −π/4) ・
” (4) eb=Esin(ωot king θB +rr/4
) −(5) where E is the voltage amplitude, θ
e=θm/(P/2), θe... Electrical angle of the rotor rotation of the resolver 1, 0 m... The mechanical angle of the rotor rotation of the resolver 1, P... The number of poles of the resolver 1.

The square wave pulse train signals outputted from the waveform shaping circuits 7 and 8 are applied to frequency-voltage converters 9 and 10 for converting the signals into DC voltages, respectively, and the output voltages of these converters are both The output terminal 12 of the amplifier 11 outputs a signal proportional to the rotational speed.

In the above configuration, when the rotor of the resolver 1 is rotated at a rotational speed of 1 N (rpm) clockwise in the drawing, the phases of the output voltages ea and eb change as shown in the following equation.

e = Es1n(ωo+Δω)t −
(61eb =Esin(ωjiΔω) 1
−(force, where Δω−2π・Δf=2π(p
/120) N.

Δf: A frequency corresponding to the rotational speed N (rpm).

When the rotor of the resolver 1 rotates in the counterclockwise direction opposite to that described above at a rotational speed N (rpm), the signs of Δω in the true force in equation (6) above become opposite.

The above two (6) and (7) are two frequency-modulated signal voltages ea 1 according to the rotation speed of the rotor of the resolver 1.
This shows that eb can be obtained. FIG. 2 shows the voltage waveforms of these signal voltages ea, eb and excitation voltage ex, with the horizontal axis representing time t1 and the vertical axis representing voltage values.

In the same figure, the excitation voltage of the resolute 1 has a constant period To (=1/fo), but the voltage ea has a period Ta [-17 (f o + Δf ) ) k which is shorter than the period To.
Also, the voltage eb has a period 1°・' which is longer than the period To.
rb [= 1/(fo-△f), 1] f, and the periods Ta and Tb change according to increases and decreases in the rotational speed N. Figure 6 shows the rotation direction (±) and rotation speed N'lr on the horizontal axis.
The frequency fffi of the voltage e a He B is plotted on the vertical axis, and a curve A shows the frequency change of the voltage ea with respect to the rotational direction and rotation speed, and a curve B shows the frequency change of the voltage eb. As seen in the figure, when the rotor is stopped, that is, when N=00, the frequency f becomes fo for both curves A and B, and the clockwise rotational speed 10N (or counterclockwise rotational speed - N) increases. As the frequency f of curve A increases (or decreases), the frequency f of curve B decreases (or increases). Therefore, the change in frequency f with respect to the change in rotational speed N is the sum of the change due to song aA and the change due to curve B, which means that a frequency change that is twice as much as when using only curve A is obtained. . Therefore, the voltage ea
frequency (fo±Δf) and frequency of voltage eb (fo+
Δf) is converted into a voltage by the frequency-voltage converter 9 or 10 via the waveform shaping circuit 7 or 8, respectively, and the difference voltage between the two voltages is amplified by the differential amplifier 11, and the output terminal 12
If we take it out from the equation, the frequency change corresponding to the rotation speed is 2Δ
A speed signal voltage corresponding to f can be obtained. When a speed signal proportional to the rotational speed is obtained as described above, the rotational speed is detected using a single frequency modulation signal obtained using a conventional resolver, and the detection method is to convert the frequency to voltage to obtain the rotational speed signal. In comparison, using a resolver with the same number of poles, it is possible to detect the rotational speed with twice the detection sensitivity, that is, with a detection sensitivity equivalent to a resolver with twice the number of poles.

Next, each output voltage ea of the two phase shifters Sl and S2 is
Another embodiment of the means for obtaining a speed signal proportional to the rotational speed based on +eb will be described with reference to FIGS. 4 and 5. In FIG. 4, Pl and P2 are the phase shifters S1. This figure shows portions corresponding to the signal output terminals PI and P2 of S2, and the configuration up to the signal output terminals is the same as that in FIG. 1, so illustration is omitted. 21 is a third phase shifter that receives the output voltage eak from the signal output terminal Pl, and 22 is a fourth phase shifter that receives the output voltage ebk from the signal output terminal P2. For example, the phase φ of the output voltage ec or ed with respect to the frequency f of the voltage ea or e has lead or lag phase shift characteristics as shown in FIG. It shall have a leading phase shift characteristic. 23 and 24 are the above voltages e, e or voltage eb1a, respectively.
Multipliers 25 and 26 that receive and multiply C ed are low-pass filters that receive the output signal of multiplier 23 or 24, respectively, attenuate its high frequency components, and output DC component voltage Ec or Ed'. 27 is a differential amplifier that receives the output voltage Ec + E d of the low-pass filter of the Korera and outputs a voltage Eei obtained by amplifying the difference voltage.

In the above configuration, if voltages ea 1 e6 are respectively expressed by the above equations (6) and (7),
The voltages e cr 86 are each expressed by the following equations.

ec=E 5inc(ω0−1−Δω)t+φ. :]
=18)6d=EsinC(ω0−Δω)t+
φd': l − (9) where φ. and .phi.d indicate the phase shift angle of the voltage phase determined by .omega. (-2.pi. .mu.f), respectively, and are on the solid line characteristic in FIG. The output voltage e xe of the multiplier 23 and the output Ca voltage edXeb of the multiplier 24 are each given by the following equation.

e Xe =E2sin[(ω+Δω)t+φ. ]ψs
]n(ω+△ω)t a 2 11[worldφ−■(2(ω+muω)t+φ)] ・・・(
10) 2c
ced X eb= E'5in(:(ω-Δω)t
+φd) sin(ω-t, ω) as shown in the above equation (10),
Since the second term within 0 in 011 is a high frequency component, low pass filters 25 and 26 are used to remove the high frequency component.
The output voltages Ec and Ed are respectively given by the following equations.

2 Ec=-4φ. ...(
12) Phase shift angle φ in the above equation. , φ, is 90° when the frequency f to the excitation voltage is fo, as seen in Fig. 5, so the phase shift angle change corresponding to the frequency modulation signal Δf is expressed as the progressive phase shift characteristic in Fig. 5. In the light, 壬muφ and ±
If Δφ, the above equations (121 and (13)) are given by the following equations, respectively.

E・= −cry, (9゜・壬−φ)= “” si
・(shiheφ) ...α(a)2 2 C2C As can be seen from the above equation, the phase shift angle Δφ. , Δφd is in the range of Δφ215° and Δφd≦15°, respectively, the voltage is -
- Ec and Ed have linearity7, and the polarity of these voltages is reversed depending on the rotation direction. Therefore, the output voltage Ee of the differential amplifier 27 becomes a speed signal voltage which is proportional to the rotational speed N and whose polarity differs depending on the rotational direction.

As described above, the present invention applies an excitation signal to the excitation winding of a resolver having a -phase excitation winding and two-phase output windings (Wα, Wβ), The two output signals outputted from the engine are synthesized to obtain two different frequency modulation signals, and the rotational speed signal is obtained based on the frequency difference between the two frequency modulation signals. Compared to conventional detection based on frequency changes,
With twice the sensitivity, highly reliable rotational speed detection can be performed by brushless technology. It's cool, claim 2
According to the invention, two phase shifters each consisting of a series connection circuit of a capacitor and a resistor are used to connect the capacitor input side of the first phase shifter and the resistor of the second phase shifter. The output of the output winding (Wα9) is added to the input side, and the output of the output winding (Wβ) is added to the resistor input side of the first phase shifter and the capacitor input side of the second phase shifter. Therefore, it is possible to easily obtain two different frequency modulation signals based on each output signal of the output windings (Wα, Wβ) using a phase shifting means having an extremely simple configuration. The rotation speed signal is obtained by converting the two frequency modulated signals into voltages and amplifying the difference between the direct voltages, so that the fc voltage signal is proportional to the rotation speed from the two frequency modulated signals. It is possible to provide a highly reliable rotational speed detection device that is brushless, easy to maintain, and has high sensitivity.

Furthermore, according to the invention of claim 3, the two frequency-modulated signals are each added to a phase shifter to shift the phase according to the frequency, and the phase-shifted signals are applied to a multiplier and a multiplier. Two voltages corresponding to each phase shift angle are obtained through the low-pass filter, and a rotational speed signal is obtained based on the difference between the two mold pressures. Based on the phase shift angle, a voltage signal proportional to the rotational speed can be obtained with extremely high detection sensitivity.

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing an overview of an embodiment of the present invention, Fig. 2 is a waveform diagram showing voltage waveforms of the main parts of the device in Fig. 1, and Fig. 5 is a voltage e a + e B in Fig. 1. FIG. 4 is a block diagram showing the configuration of main parts of another embodiment of the present invention, and FIG. 5 is a characteristic curve showing an example of the characteristics of the phase shifter in FIG. 4. It is a diagram. 1... Resolver, Wx... Excitation winding, Wα, Wβ・
... two-phase output winding, 2... sine wave signal oscillator, S],
S2... Phase shifter, 7, 8... Waveform shaping circuit, 9, 1
0... Frequency-voltage converter, 11.27... Differential amplifier, 21°22... Phase shifter, 23.24... Multiplier, 25, 26... Low pass filter. Agent Patent Attorney Hidetoshi Matsumoto ・・・・１・（′
It's a bug! Nrokubi 11 6, HlIO Yoshi station return to the outside.

Claims (3)

[Claims] (1) An excitation signal Ex is applied to the excitation winding of a resolver having a -phase excitation winding and a two-phase output winding (Wα, Wβ).
sinωat (However, Ex...voltage amplitude, ω0...
angular velocity, t...time), and the output winding (Wα)
The output signal EIS1nω6t'CQSθe from the output winding (Wβ) is combined with the output signal EIS1nω6t'CQSθe from the output winding (Wβ). , two different frequency modulation signals Es1n(ω0Δω)1 (where E: voltage amplitude, Δω: angular velocity depending on the rotation direction and rotation speed), and Es1o(ω0Δω)t are obtained. A rotation speed detection method using a resolver, characterized in that a rotation speed signal is obtained based on the frequency difference between the two frequency modulation signals. (2) A resorno (with a one-phase excitation winding on the rotor and two-phase output windings (Wα, Wβ) on the stator, and a series connection circuit of a capacitor and a resistor with a capacitor input side of V A first phase shifter whose resistor input side is connected to the output end of the output winding (Wα) and the output end of the output winding (Wβ), and a resistor input consisting of a series connection circuit of a resistor and a capacitor. a second phase shifter whose side is connected to the output end of the output winding (Wα) and whose capacitor input side is connected to the output end of the output winding (Wβ); a first frequency-to-voltage converter that receives an output signal and converts its frequency into a full voltage; and a second frequency-to-voltage converter that receives an output signal from the second phase shifter and converts its frequency into a voltage. A resolver comprising: a converter; and a differential amplifier that receives both output voltages of the first and second frequency-voltage converters, amplifies the difference voltage therebetween, and outputs it as a rotational speed signal. Rotation speed detection device. (3) A resolver having a one-phase excitation winding on the rotor and a two-phase output winding (Wα, Wβ) on the stator, and a series connection circuit of a capacitor and a resistor. a first phase shifter having an output end of the wire (Wα) and a resistor input end connected to the output end of the output winding (Wβ), respectively;
A second phase shifter consisting of a series connection circuit of a resistor and a capacitor, with the resistor input side connected to the output end of the output winding (Wα), and the capacitor input side connected to the output end of the output winding (Wβ), respectively. a third phase shifter receiving the output signal from the first phase shifter; a fourth phase shifter receiving all the output signals from the second phase shifter; a multiplier of 81!1 which receives the Okayama Chi No. 8 of the first phase shifter and multiplies it; and a second multiplier which receives the Okayama Rika No. of the fourth and second phase shifters and performs #l calculation. a first low-pass filter that receives the output signal of the first multiplier and produces an output with its high frequency components removed; and a first low-pass filter that receives the output signal of the second multiplier and produces an output with its high frequency components removed. The present invention is characterized in that it is equipped with a second low-pass filter that generates a rotational speed signal, and a differential amplifier that receives the Okayama force voltages of the first and second low-pass filters, amplifies the difference voltage, and outputs it as a rotational speed signal. Rotation speed detection device using a resolver.