JPH03238317A - Wire-break detecting circuit of magnetic resolver - Google Patents

Abstract

PURPOSE:To detect abnormalities for any combination of wire breaks by providing an amplitude-level detecting circuit, an abnormal-amplitude-decrease detecting circuit and an abnormal-amplitude-level-increase detecting circuit. CONSTITUTION:An amplitude-level detecting circuit 21 detects the amplitude of a phase modulation signal. An abnormal-amplitude-level decrease detecting circuit 22 generates a wire break signal when the detected amplitude of the circuit 21 is smaller than a specified reference value. The reference value is set at a value smaller than the amplitude of the phase modulation signal when there is no wire break in the connecting wire of a coil wound around a salient pole. An abnormal-amplitude-level-increase detecting circuit 3 generates a wire break signal when the detected amplitude of the circuit 21 is larger than the specified reference value. The reference value is set at a value larger than the amplitude of the phase modulation signal when there is no wire break in the connecting wire of a coil wound around the salient pole. The wire breaks in all combinations which are liable to occur in practical applications can be detected with both the circuit 3 which detects the abnormal increase in detected signal of the magnetic resolver and the circuit 22 which detects the abnormal decrease.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is directed to improving a disconnection detection circuit for a phase modulation type magnetic resolver.

<Conventional technology> Conventionally, as a disconnection detection circuit for such a magnetic resolver,
For example, there was a configuration shown in FIG.

In the figure, 1 is a magnetic resolver, and 2 is a disconnection detection circuit.

The magnetic resolver 1 includes a resolver section 11, an excitation circuit 12, and a phase detection circuit 13.

The resolver section 11 is manufactured by the patent application No. 632188 filed by the present applicant.
This is stated in the application specification of No. 92.

In the resolver section 11, 111 to 114 are coils wound at the end of the rotor.The stator of the resolver section 11 has salient poles formed at different positions of 90 degrees in mechanical angle, 0 degree position, 90 degree position. position.

Coils 111, 112, 113, and 114 are wound around the salient poles at the 180° and 270° positions, respectively.

Teeth with a pitch of P are formed at the tip of each salient pole, and 0°
The teeth of the salient pole at the 90°, 180”, and 270° positions have phases of O and (1/1/2, respectively) with respect to the reference position.
4)P.

They are shifted by (2/4)P and (3/4)P.

Reference numeral 115 denotes a rotor, which rotates together with the rotation detection object, for example, a rotor. The rotor 115 has teeth formed at a pitch P at positions facing the teeth of the salient poles of the stems. CNI~
CN6 is a connector for connecting each coil.

In the excitation circuit 12, 121 connects the coils 111 and 113 to Es
AC voltage of 1 nωt (E is the amplitude of the voltage, ω is the angular velocity,
t is time), and 122 is a signal source that excites the coils 112 and 114 with an AC voltage Ecosωt.

In the phase detection circuit 13, R+, R2, R3, and Ra are currents II flowing through the coils 111, 113, 112, and 114.
I I2. I3. Is to voltage V+, Va,
V3 is a resistance that converts to Va.

131 is a subtracter that takes the difference between V and 2; 132 is a subtracter that takes the difference between V and V4; and 133 is an adder that adds the difference signals Va and Vb of the two subtracters.

This addition signal vc becomes a motor rotation detection signal.

In the disconnection detection circuit 2, 21 is an amplitude level detection circuit that detects the amplitude of the detection signal VC, and 22 is an amplitude level abnormal decrease that generates an abnormality detection signal ERI when the detected amplitude level is lower than the reference value VREF+. This is a detection circuit.

In such a circuit, if there is no disconnection in any of the connectors CNI to CN6, the voltages V, to v4 are given by the following equations.

V+ = a (if (m/2)cosplXsinω
t Va =a (1-(m/2)cosψ)Xsinωt V3 =a fl+ (m/2)sin95)XC
O8ωt Va -a (1-(m/2) sin9')xc
osωt a: constant 1m: constant ((1) ψ: rotor rotation angle Based on these voltages, the phase detection circuit 13 performs the following calculation to obtain a phase-modulated detection signal Vc.

V (=V, v2+v, v4 =ams in (ωt+p) Amplitude level detection time #121 detects the amplitude am of vc. Here, since am>VRE F l is set, the amplitude level is abnormally lowered. Detection circuit 22 generates a signal indicating no abnormality.

<Problem to be solved by the invention> However, if only connector CN3 is disconnected, m
(From 1, the detection signal vc is given by the following equation.

Vc = -v2+v, -v.

=-a (1-(m/2) cossi'1xsi
nωt +ams i npcosωt nee acospsinωt From this detection signal Vc, @width and bell detection circuit 21
Detect a. Here, since a>am, a>VRE p
1, so the amplitude level abnormality drop detection circuit 22 generates a signal indicating no abnormality.

For this reason, a disconnection is not detected even though a disconnection actually occurs.

The magnetic resolver gable was connected incorrectly at the customer's site.

Wire breakage may occur due to poor soldering or bent cables.

If a false signal unrelated to the original magnetic resolver detection signal is sent to the motor control circuit due to a disconnection, the motor may run out of control.

The present invention has been made to solve these problems, and an object of the present invention is to realize a disconnection detection path for a magnetic resolver that can detect abnormalities in any combination of disconnections.

Means for Solving the Problems> The present invention comprises a rotor in which teeth are formed at a pitch P, and salient poles are provided at positions where the mechanical angle differs by 90 @, and the tip of each salient pole has the above-mentioned shape. Si
Excited with an n-phase AC signal, the salient pole at 90° position and 27
A signal source that excites a coil wound around a salient pole at the 0° position with a cos-phase alternating current signal, a difference between the currents flowing through the coil excited by a sine-phase alternating current signal, and an excitation using a cos-phase alternating signal. an arithmetic unit that calculates a phase modulation signal whose phase changes by 360 degrees when the rotor rotates once by adding the difference between the currents flowing through the coils, and calculating the amplitude of the phase modulation signal. An amplitude level detection circuit detects, and a disconnection signal is generated when the detected amplitude of this amplitude level detection circuit is smaller than a predetermined reference value, and this reference value is the phase when there is no disconnection in the connection wire of each coil. An abnormal amplitude level drop detection circuit is set to a value smaller than the amplitude of the modulation signal, and a disconnection signal is generated when the detected amplitude of the amplitude detection circuit is larger than a predetermined reference value, and this reference value is A disconnection detection circuit for a magnetic resolver, comprising: an amplitude level abnormal rise detection circuit that is set to a value larger than Ii@ of a phase modulation signal when there is no disconnection in the connection wire of each coil.

In the present invention, all combinations of disconnections that may occur in practice are detected using both the circuit for detecting an abnormal increase in the amplitude of the detection signal of the magnetic resolver and the circuit for detecting an abnormal decrease in the amplitude.

<Example> The present invention will be explained below using the drawings.

FIG. 1 is a configuration diagram of an embodiment of a disconnection detection circuit for a magnetic resolver according to the present invention. Components in FIG. 1 that are the same as those in FIG. 4 are given the same reference numerals.

In FIG. 1, reference numeral 3 denotes an amplitude level abnormality increasing circuit which is a feature of the present invention, and generates an abnormality signal ER2 when the detected amplitude Vd of the amplitude level detection circuit 21 is higher than the reference value VREF2.

The reference values VREFt and VREF2 are set to the following magnitudes.

0<VRE F t <am<Vg E p 2 <a
■The relationship between each disconnection combination and the detected amplitude vd of the amplitude level detection circuit 21 is shown in FIG. 2. As shown in this figure, the detected amplitude vd is O, ams in Sl+1°an
It can be either cosp, a, or J2a. The magnitude relationship between these detected amplitudes and the reference value can be expressed graphically as shown in FIG. 3.

From the condition (2), a disconnection can be detected except in the cases where lams i n ψ1≧VREF+ and lamcos ψl≧VIEFt.

Considering that the motor rotates, realistically it is always 1a.
msinpl≧VREF+.

Since amcos9DI≧VREFt does not hold, a disconnection can be detected in all cases in practice.

Effects> According to the present invention, since wire breakage is detected from both an abnormal decrease and an abnormal rise in the amplitude of the detection signal of the magnetic resolver, it is possible to detect all combinations of wire breaks of the magnetic resolver that may occur in practice.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 and FIG.
1 is an explanatory diagram of the operation of the circuit shown in FIG. 1, and FIG. 4 is a diagram showing an example of a top configuration of a conventional disconnection detection circuit for a magnetic resolver. 1... Magnetic resolver 11... Resolver section, 12.
... Excitation circuit, 13... Phase detection circuit, 2... Disconnection detection circuit, 21... Amplitude level detection circuit, 22...
Abnormal amplitude level decrease detection circuit, 3... Abnormal amplitude level increase detection circuit.

Claims (1)

[Claims] A rotor with teeth formed at a pitch P, salient poles are provided at positions that differ by 90 degrees in mechanical angle, and the tip of each salient pole has teeth formed at a pitch opposite to the teeth of the rotor. Si
Excited with an n-phase AC signal, the salient pole at 90° position and 27
A signal source that excites a coil wound around a salient pole at the 0° position with a cos-phase alternating current signal, the difference between the currents flowing through the coil excited by a sine-phase alternating current signal, and excitation with a cos-phase alternating signal. an arithmetic unit that calculates a phase modulation signal whose phase changes by 360 degrees when the rotor rotates once by adding the difference between the currents flowing through the coils, An amplitude level detection circuit detects, and a disconnection signal is generated when the detected amplitude of this amplitude level detection circuit is smaller than a predetermined reference value, and this reference value is the phase when there is no disconnection in the connection wire of each coil. an amplitude level abnormal decrease detection circuit set to a value smaller than the amplitude of the modulation signal; and a disconnection signal is generated when the detected amplitude of the amplitude detection circuit is larger than a predetermined reference value, and this reference value is set to a value smaller than the amplitude of the modulation signal. A disconnection detection circuit for a magnetic resolver, comprising: an amplitude level abnormal rise detection circuit that is set to a value larger than the amplitude of a phase modulation signal when there is no disconnection in the connection wire of each coil.