JPS60162920A - Resolver device using magnetism sensing element - Google Patents

Abstract

PURPOSE:To drive a resolver device efficiently with a little electric power by providing a magnet rotor, two magnetism sensing elements, and a function generator which sends out a sin and a cos signal, and processing respective output signals by a multiplier and an adder. CONSTITUTION:Two magnetism sensing elements 21 and 22 are arranged at an interval of an electric angle pi/2 or its odd multiple in a magnetic field established by the magnet roller 23 magnetized to 2n (n; integer more than 1) in the circumferential direction of rotation, and they are driven by the common DC power source 24. The function generator 28, on the other hand, generates the sin signal and cos signal which have a phase difference of the electric angle pi/2, those output signals and output signals of the magnetism sensing elements 21 and 22 are multiplied by two sets of multipliers 25 and 26 respectively, and their outputs are added together by an operational amplifier 27 which constitutes an adding circuit. Thus, precise detection is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resolver device using a magnetically sensitive element.

Conventionally, resolvers are one of the means of detecting rotation angles.
As an example of the apparatus, the system shown in FIGS. 1 and 2 is known.

In FIG. 1, reference numeral 1.2 denotes a stator coil, these stator coils 1.2 are arranged 90' apart from each other, and one stator coil 1 receives a signal cosωt from a cos signal generator 6. A signal sinωt is applied to the other stator coil 2 from a sin signal generator 7 via an amplifier 5. Further, a rotor coil 3 is provided beside the rotor 8, and an output signal is obtained from the rotor coil 3. Above two stator coils 1
．． The CO8 signal and the sine signal that are applied to the signal line 2 have an electrical phase difference of 90°. From rotor coil 3,
A secondary output waveform in which the rotor position is phase-shifted by θ° from the absolute zero point is obtained, and thereby the rotation angle of the rotor 8 can be detected.

The example shown in FIG. 2 uses magnetic sensing elements without using a detection coil, and two magnetic sensing elements 11 are placed in the magnetic field of a magnet rotor 13 magnetized in the circumferential direction of rotation.
．． 12 are arranged at an electrical angle of π/2 apart, one magnetically sensitive element 11 receives a signal cosωt from a CQ3 signal generator 14, and the other magnetically sensitive element 12 receives a signal sinωt from a sine signal generator 15. In addition, a signal corresponding to the rotation angle of the rotor is extracted from the output ends of magnetically sensitive elements 11 and 12 connected in series with each other.

In any of the above conventional examples, the cos signal generator and the sin
Since the cosine signal and the sine signal generated by the signal generator are used to energize a coil or a magnetically sensitive element, a relatively large amount of power is required, and an amplifier is also required. In addition, since the coil or magnetic sensing element is driven at a relatively high frequency (approximately 10Kllz to 50Kllz), if the length from the drive circuit to the stator is increased, the waveform may be distorted or have frequency characteristics, making it difficult to drive efficiently. There was also the problem that it was difficult to carry out this process, and external noise was easily picked up.

An object of the present invention is to provide a resolver device using a magnetically sensitive element by eliminating the need to directly drive the magnetically sensitive element with a cosine signal or the like, and by making it possible to perform arithmetic processing on the detected signal only within the circuit. Another object of the present invention is to provide a resolver device using a magnetically sensitive element that requires only a small amount of electric power, can be driven efficiently, and is not easily affected by external noise.

The present invention is characterized by a magnet rotor magnetized to 2n (n is an integer greater than or equal to 1) poles, and two magnets arranged at an electrical angle of π/2 or an odd multiple thereof in the magnetic field generated by the magnet rotor. a sensing element, a function generator that generates a sine signal and a cosine signal having a phase difference of electrical angle π/2, and each output signal of this function generator and each output signal of the two magnetic sensing elements, respectively. The present invention is provided with two sets of multipliers for multiplication and an adder for adding the respective output signals of the multipliers.

The invention will now be described with reference to the embodiment shown in FIG.

In FIG. 3, reference numeral 23 denotes a magnet rotor, and the magnet rotor 23 is magnetized to have 2n (n is an integer greater than or equal to 1) poles in the rotational circumferential direction. Two magnetically sensitive elements 21 are located within the magnetic field generated by the rotor magnet 23.
．． 22 are arranged at electrical angles of π/2 or an odd multiple thereof, and each magnetically sensitive element 21, 22 is driven by a common DC power source 24 for driving the magnetically sensitive element. Each of the magnetic sensing elements 21 and 22 detects the phase of the rotor magnet 23, and as the rotor magnet 23 rotates, one of the magnetic sensing elements 21 and 22 has cosθ.
A signal of sin θ is generated in the other magnetic sensing element. The output of the magnetically sensitive element 21 is input to a multiplier 25, and the output of the other magnetically sensitive element 22 is inputted to a multiplier 26. Multiplier 25
multiplies the signal from the magnetically sensitive element 21 and the signal by cosω generated by the function generator 28, and also multiplies the signal from the multiplier 2
6 multiplies the signal from the magnetically sensitive element 22 and the signal by sin ω generated by the function generator 28 . The cos ω signal and sin ω signal generated by the function generator 28 range from several K11z to several tens of K II z
Furthermore, both of the above signals have a phase difference of π/2 in electrical angle. The outputs of each multiplier 25 and 26 are added by a 5-way adder including an operational amplifier 27, and this added signal is output as a detection signal.

Now, suppose that a cos θ signal is generated in the magnetically sensitive element 21, and a sin θ signal is generated in the other magnetically sensitive element 22. The above cos θ signal is multiplied by the cos ωt signal from the function generator 28 in the multiplier 25, while the above s
The in θ signal is multiplied by a sin ω signal from a function generator 28 in a multiplier 26 . Each multiplier 25.26
The multiplication results in are added by an adder including an operational amplifier 27, and the result is output as a detection signal Fout.

Expressing the above calculation operation in a formula, Fout= cosωt
−cosθ+sinωtψsinθ− 工(cos (
ωt-θ) + cos (ω to one θ)) + k (cos
(ω minus θ) − cos (ωt + θ)) = cos (
ω is one θ). As is clear from the above equation, the output Font is an output phase-modulated by the rotation angle θ of the magnet rotor 23, and thereby a resolver operation is performed.

Note that the output signal Font_t is 6 from the function generator 28.
- Since the signal is shifted by θ° with cosω as the reference signal, a digital output representing the absolute angle θ can be obtained, for example, by counting the clock pulses existing within the deviation angle θ°. Furthermore, when detecting the rotational speed of the magnet rotor, the rotational speed can be calculated by detecting a change in θ using a phase detector and reading the frequency of the change.

As a magnetic sensing element, a Hall element and a magnetoresistive element (M
R element) can be used.

According to the present invention, there are the following effects.

(1) Since it is not necessary to drive the magnetically sensitive element with cosine and sine signals that require high precision, the frequency characteristics of the position detection signal are determined by the frequency characteristics of the magnetically sensitive element alone, allowing highly accurate detection. I can do it.

(2) There is no need for an amplifier that drives a relatively large current.

(3) Since no high-frequency drive current flows between the drive circuit and the magnetically sensitive element, the detection signal will not be interfered with even if the wire connecting the drive circuit and the magnetically sensitive element is long. , there is no external noise.

(4) The other circuit parts except the magnetically sensitive element are arithmetic circuits consisting of a function generator, multiplier, and adder, and there is no drive circuit part for the magnetically sensitive element, so power consumption is reduced and it can be integrated into an IC. In this case, a small chip IC without drive pins can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional resolver device, FIG. 2 is a circuit diagram showing another example of the conventional resolver device, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. 21.22... Magnetic sensing element 23... Magnet rotor 25.26... Multiplier 27... Operational amplifier constituting the adding circuit 28... Function generator 11

Claims (1)

[Claims] A magnet rotor magnetized to 2n (n is an integer greater than or equal to 1) poles, two magnetic sensing elements arranged in the magnetic field generated by the magnet rotor with an electrical angle of π/2 or an odd multiple thereof, and an electrical angle of π/2 or an odd multiple thereof. A function generator that generates a sine signal and a cosine signal having a phase difference of π/2, and two sets of multipliers that multiply each output signal of this function generator and each output signal of the two magnetically sensitive elements, respectively. 1. A resolver device using a magnetically sensitive element, characterized in that it comprises a multiplier and an adder for adding up each output signal of the multiplier.