JPH04295293A - Rotational position detecting equipment - Google Patents

Abstract

PURPOSE:To detect an absolute value of a rotation angle in a body of rotation stably and with a high resolution by generating a sine wave signal, a cosine wave signal, an inverse sine wave signal and an inverse cosine wave signal based on the rotating motion of a body of rotation and further by detecting an absolute rotational position based on a linear approximate signal and a division signal further generated. CONSTITUTION:Based on the rotating motion of a body of rotation, a sine wave signal S (SIN), an inverse sine wave signal S(-SIN) and a cosine wave signal S(COS) and an inverse cosine wave signal S (-COS) are generated. From these four signal waveforms, a linear approximate signal S20 is obtained. Moreover, by comparing the signal level of these four signals, the division signals SD1, SD2, SD3 and SD4 dividing the absolute rotation angle of the body of rotation for respective linear approximate regions are obtained. Here, based on the linear approximate signal S20 and divided signals SD1, SD2, SD3 and SD4, the absolute rotational position is detected by a rotational position detection circuit 32. By doing this, the absolute rotational position of the body of rotation can be detected stably and with a high resolution.

Description

[Detailed description of the invention]

0001

[Table of Contents] The present invention will be explained in the following order. Industrial application field Conventional technology (Figure 5) Problem to be solved by the invention (Figure 5) Means for solving the problem (Figures 1 and 4) Effect (Figure 1)
and Figure 4) Examples (Figures 1 to 4) Effects of the invention

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational position detection device, and is suitable for application to, for example, a rotational position detection device for a brushless motor.

0003

[Background Art] Conventionally, in brushless motors, rotation angle detection is performed in which the magnetic field of the rotor magnet is detected using a rotation detection element such as a Hall element, and the signal level changes depending on the rotation angle of the rotor magnet. It is designed to get a signal.

That is, as shown in FIG. 5, the rotation angle detection signal S1 changes sinusoidally between the maximum level and the minimum level with one rotation of the rotor magnet as one cycle. By detecting the level, the absolute amount of rotation angle (
In other words, the rotational position) is detected.

[0005]

[Problem to be Solved by the Invention] However, when trying to detect a rotation angle using such a sinusoidal (that is, curved) rotation angle detection signal S1, the rotation angle detection signal S
1 near the maximum level (i.e. rotation angle 90°) and around the minimum level (i.e. rotation angle 270°),
Since the amount of change in the signal level of the rotation detection signal S1 is smaller than the amount of change in the rotation angle, the rotation angles are 90° and 27°.
There was a problem in which the resolution deteriorated when detecting the rotation angle near 0°.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a rotational position detection device that can stably detect the absolute amount of rotational angle of a rotating body with high resolution. .

[0007]

[Means for Solving the Problem] In order to solve the problem, in the present invention, predetermined rotation detection elements HE1, HE
In the rotational position detection device 10 that detects the rotational position of a rotating body using
11, and a cosine wave signal S(C
cosine wave signal generating means HE2, 13 for generating the OS);
Inverted sine wave signal generation means HE1, 12 that generates an inverted sine wave signal S (-SIN) by inverting the sine wave signal S (SIN) based on the rotational movement of the rotating body; inverted cosine wave signal generation means HE2, 14 that generates an inverted cosine wave signal S (-COS) by inverting the cosine wave signal S (COS), and sine wave signal S (SIN) and cosine wave signal S (COS). ) as well as the inverted sine wave signal S(
-SIN) and inverted cosine wave signal S (-COS), respectively, linear approximation areas LIN1, LIN2, LIN3
, LIN4, linear approximation signal generation means 21, 22, 23 generate a linear approximation signal S20 based on linear approximation areas LIN1, LIN2, LIN3, LIN4, and linear approximation areas LIN1, LIN2, LIN3,
The linear approximation signal S20 and the divided signals SD1, SD2, SD3, SD4 generated by the divided signal generating means 30 are provided with a divided signal generating means 30 that divides each LIN4.
The absolute rotational position of the rotating body is detected based on this.

[0008]

[Operation] Based on the rotational movement of the rotating body, the sine wave signal S (S
IN), an inverted sine wave signal S (-SIN) obtained by inverting the sine wave signal S (SIN), and a cosine wave signal S (
COS) and the inverted cosine wave signal S(-COS) obtained by inverting the cosine wave signal S(COS), and linear approximation areas LIN1 and LIN2 of these four signal waveforms are respectively generated.
, LIN3, and LIN4 are obtained, and further a sine wave signal S (SIN), an inverted sine wave signal S (-SIN), a cosine wave signal S (COS), and an inverted cosine wave signal S ( -COS), the absolute rotation angle of the rotating body is determined by linear approximation area LIN1.
, LIN2, LIN3, and LIN4 are obtained, and the divided signals SD1, SD2, SD3, and SD4 are obtained, and the linear approximation signal S20 and the linear approximation that change linearly with changes in the absolute rotational position and minutely represent the rotational position are obtained. Signal S20
A divided signal SD that roughly specifies the region of rotation angle represented by
1. By detecting the absolute rotational position based on SD2, SD3, and SD4, the absolute rotational position of the rotating body can be detected more stably and with higher resolution.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 10 indicates a rotational position detection device as a whole, and for example, two Hall elements HE1 and H are arranged around a two-pole rotor magnet at an angular interval of 90°.
E2 is arranged so that its magnetically sensitive surface is perpendicular to the rotating magnetic field.

[0011] First and second Hall elements HE1 and HE
2 are bias currents IH1 and I from the power supply VCC, respectively.
Detection signals S11, S12 and S13 that change according to the rotation of the rotor magnet by being supplied with H2,
Output S14.

Detection signal S11 of first Hall element HE1
and S12 are input to the inverting input terminal and non-inverting input terminal of the comparator circuit 11 via resistors R1 and R2, respectively.

The comparator circuit 11 has a negative feedback loop formed by a feedback resistor R6, and its non-inverting input end is connected to ground via a resistor R7.

Therefore, the output signal of the comparator circuit 11 is as shown in FIG.
As shown in (A), a sine wave sinθ(θ
represents the absolute rotation angle).
The signal is then input to the diode D1 of the minimum value detection circuit 21, and is also input to the rotation angle dividing circuit 30 into four.

Furthermore, the detection signal S of the first Hall element HE1
11 and S12 are input to the non-inverting input terminal and the inverting input terminal of the comparator circuit 12 via resistors R3 and R4, respectively.

The comparator circuit 12 has a negative feedback loop formed by a feedback resistor R8, and its non-inverting input end is connected to ground via a resistor R9.

Therefore, the output signal of the comparison circuit 12 is as shown in FIG.
As shown in (A), an inverted sine wave signal S consisting of an inverted sine wave − sin θ obtained by inverting the above sine wave signal S (SIN)
(-SIN), and is input to the diode D3 of the subsequent minimum detection circuit 22, and is also input to the rotation angle four-divider circuit 30.

On the other hand, the detection signals S13 and S14 of the second Hall element HE2 are detected by the resistors R11 and R1, respectively.
2 to the inverting input terminal and non-inverting input terminal of the comparator circuit 13.

The comparator circuit 13 has a negative feedback loop formed by a feedback resistor R16, and its non-inverting input end is connected to ground via a resistor R17.

Therefore, the output signal of the comparison circuit 13 is as shown in FIG.
As shown in (A), a cosine wave signal S (COS) consisting of a cosine wave cos θ changes by one period from the maximum amplitude value while the rotor magnet makes one rotation from an absolute rotation angle of 0° to 360°. is input to the diode D2 of the following minimum detection circuit 21, and is also input to the rotation angle 4-dividing circuit 3.
It is input to 0.

Furthermore, the detection signal S of the second Hall element HE2
13 and S14 are input to the non-inverting input terminal and the inverting input terminal of the comparator circuit 14 via resistors R13 and R14, respectively.

The comparator circuit 14 has a negative feedback loop formed by a feedback resistor R18, and its non-inverting input end is connected to ground via a resistor R19.

Therefore, the output signal of the comparison circuit 14 is as shown in FIG.
As shown in (A), an inverted cosine wave signal S(-cosθ) is an inverted cosine wave signal S(COS).
COS), and then the diode D of the minimum detection circuit 22
4 and is also input to the rotation angle dividing circuit 30 into four.

The minimum detection circuit 21 includes diodes D1 and D
The anode side of 2 is connected to the power supply VC through the resistor R21.
C, and its cathode sides are connected to the output ends of the comparison circuits 11 and 13, respectively.

Therefore, the diode D1 is forward-connected from the power supply VCC side to the comparison circuit 11 side, and the diode D2 is forward-connected from the power supply VCC side to the comparison circuit 13 side. At the common output terminal a on the anode side of each of the diodes D1 and D2, a waveform with a smaller signal level among the sine wave signal S (SIN) and the cosine wave signal S (COS) is selectively output.

Therefore, the output signal from the common output terminal a is converted into a sine wave signal S (SIN) as shown in FIG. ) and cosine wave signal S (COS
) is crossed at time points t1 and t3, a minimum detection signal S16 which switches to the waveform side with a smaller signal level is obtained, and is sent to the diode D7 of the maximum detection circuit 23 that follows.

On the other hand, in the minimum detection circuit 22, the anode sides of the diodes D3 and D4 are connected to the power supply VCC via the resistor R23, and the cathode sides are connected to the output ends of the comparison circuits 12 and 14, respectively. .

Therefore, the diode D3 is forward-connected from the power supply VCC side to the comparison circuit 12 side, and the diode D4 is forward-connected from the power supply VCC side to the comparison circuit 14 side. An inverted sine wave signal S (-SIN) and an inverted cosine wave signal S (
-COS), a waveform with a small signal level is selectively output.

Therefore, the output signal from the common output terminal b is converted into an inverted sine wave signal S( -SIN) and inverted cosine wave signal S (-COS) cross at time points t1 and t3, the minimum detection signal S switches to the waveform side with a smaller signal level.
17, followed by the diode D of the maximum detection circuit 23.
Send on 8th.

The maximum detection circuit 23 includes diodes D7 and D
The cathode sides of 8 are each connected to the ground via the resistor R25, and are also connected to the common output terminal c.

Therefore, the diode D7 is the minimum detection circuit 21.
The diode D8 is connected in the forward direction from the side to the common output terminal c side, and the diode D8 is connected in the forward direction from the minimum detection circuit 22 side to the common output terminal c side. Minimum detection signals S16 and S1
Among the 7 waveforms, the waveform with the highest signal level is selectively output.

[0032] Therefore, the output signal from the common output terminal c is passed through an amplifier circuit section consisting of a resistor R26, a diode D9, and an operational amplifier 18, so that the output signal is converted to the minimum detection signals S17 and S18 as shown in FIG. 2(D). The point at which t crosses
1 and t3, a maximum detection signal S20 is obtained which switches to the waveform side with a higher signal level.

Therefore, as shown in FIG. 3(A), this maximum detection signal S20 includes a sine wave signal S (SIN), a cosine wave signal S (COS), an inverted sine wave signal S (-SIN), and an inverted cosine wave signal S20. Time t when the signal S(-COS) crosses each
1, t2, t3 and t4, the sine wave signal S (SIN), cosine wave signal S (COS
), linear approximation areas LIN1 of the waveforms of the inverted sine wave signal S (-SIN) and the inverted cosine wave signal S (-COS), respectively.
, LIN2, LIN3, and LIN4, and the maximum detection signal S20 is sent to the subsequent rotational position detection circuit 32.

Here, the maximum detection signal S20 is a triangular wave signal, and there are multiple times when the signal level is the same (that is, at the absolute rotation angle of the rotor magnet). Signal SD1, SD
2. The rotation angle is specified based on SD3 and SD4.

That is, the rotation angle 4-dividing circuit 30 divides the sine wave signal S (SIN) sent from the comparison circuit 11 , the inverted sine wave signal S (-SIN) sent from the comparison circuit 12 , and the inverted sine wave signal S (-SIN) sent from the comparison circuit 13 . The cosine wave signal S (COS) sent from the comparison circuit 14 and the inverted cosine wave signal S (-CO
S), respectively, and input a sine wave signal S (SIN), a cosine wave signal S (COS), and an inverted sine wave signal S (-SIN).
and each linear approximation region L of the inverted cosine wave signal S (-COS)
The rotation angle 4-division signal S rises to logic “H” level at IN1, LIN2, LIN3, and LIN4, respectively.
This is a circuit that generates D1, SD2, SD3, and SD4.

That is, as shown in FIG. 4, this rotation angle 4-dividing circuit 30 inputs a sine wave signal S (SIN) to the inverting input terminal of the comparator circuit 31A, and also inputs a cosine wave signal S (COS) to the non-inverting input terminal. By inputting the cosine wave signal S
When the signal level of (COS) is higher than the sine wave signal S (SIN), an output signal that rises to "H" level is obtained,
This is input to the first input terminal of the AND circuit 31I.

Furthermore, the comparison circuit 31B inputs the inverted sine wave signal S (-SIN) to the inverting input terminal and also inputs the cosine wave signal S (COS) to the non-inverting input terminal. The signal level of is the inverted sine wave signal S (
-SIN), an output signal that rises to the "H" level is obtained, and this is input to the second input terminal of the AND circuit 31I.

Therefore, in the AND circuit 31I, the signal level of the cosine wave signal S (COS) is equal to the signal level of the sine wave signal S (SI
N) and the signal level of the cosine wave signal S (COS) is greater than the inverted sine wave signal S (-SIN), that is, the following equation

[Math 1] as well as

The first divided signal SD1, which rises to the "H" level when all of the following relationships are satisfied, is sent to the rotational position detection circuit 32.

Furthermore, the comparator circuit 31C inputs the cosine wave signal S (COS) to the inverting input terminal and also inputs the sine wave signal S (SIN) to the non-inverting input terminal. When the level is higher than the cosine wave signal S (COS), an output signal that rises to the "H" level is obtained, and this is input to the first input terminal of the AND circuit 31J.

Furthermore, the comparison circuit 31D inputs the inverted sine wave signal S (-SIN) to the inverting input terminal and also inputs the cosine wave signal S (COS) to the non-inverting input terminal. The signal level of is the inverted sine wave signal S (
-SIN), an output signal rising to the "H" level is obtained, and this is input to the second input terminal of the AND circuit 31J.

Therefore, in the AND circuit 31J, the signal level of the sine wave signal S (SIN) is equal to the cosine wave signal S (CO
S) and the signal level of the cosine wave signal S (COS) is greater than the inverted sine wave signal S (-SIN), that is, the following equation

[Math 3] as well as

The second divided signal SD2, which rises to the "H" level when all of the relationships shown in the equation (4) are satisfied, is sent to the rotational position detection circuit 32.

Furthermore, the comparison circuit 31E inputs the sine wave signal S (SIN) to the inverting input terminal and the inverted cosine wave signal S (-COS) to the non-inverting input terminal, thereby generating the inverted cosine wave signal S (-COS). COS) signal level is a sine wave signal S
(SIN), an output signal that rises to the "H" level is obtained, and this is input to the first input terminal of the AND circuit 31K.

Furthermore, the comparison circuit 31F inputs the cosine wave signal S (COS) to the inverting input terminal and inputs the sine wave signal S (SIN) to the non-inverting input terminal, thereby converting the signal of the sine wave signal S (SIN). When the level is higher than the cosine wave signal S (COS), an output signal that rises to the "H" level is obtained, and this is input to the second input terminal of the AND circuit 31K.

Therefore, in the AND circuit 31K, the signal level of the inverted cosine wave signal S (-COS) is equal to that of the sine wave signal S.
(SIN) and a sinusoidal signal S(SIN)
When the signal level of is greater than the cosine wave signal S (COS), that is, the following equation

[Math 5] as well as

The third divided signal SD3, which rises to the "H" level when all of the relationships shown in Equation (6) are satisfied, is sent to the rotational position detection circuit 32.

Furthermore, the comparator circuit 31G inputs the sine wave signal S (SIN) to the inverting input terminal and also inputs the cosine wave signal S (COS) to the non-inverting input terminal. When the level is higher than the sine wave signal S (SIN), an output signal that rises to the "H" level is obtained, and this is input to the first input terminal of the AND circuit 31L.

Further, the comparison circuit 31H inputs the sine wave signal S (SIN) to the inverting input terminal and inputs the inverted cosine wave signal S (-COS) to the non-inverting input terminal, thereby generating the inverted cosine wave signal S (-COS). COS) signal level is a sine wave signal S
(SIN), an output signal that rises to the "H" level is obtained, and this is input to the second input terminal of the AND circuit 31L.

Therefore, in the AND circuit 31L, the signal level of the cosine wave signal S (COS) is equal to the signal level of the sine wave signal S (SI
N) and the inverted cosine wave signal S(-COS)
When the signal level of is greater than the sine wave signal S (SIN), that is, the following equation

[Math 7] as well as

The fourth divided signal SD4, which rises to the "H" level when all of the relationships shown in Equation (8) are satisfied, is sent to the rotational position detection circuit 32.

Here, the first divided signal SD1 rises to the "H" level corresponding to the linear approximation region LIN1 of the maximum detection signal S20 (that is, the absolute rotation angle section of 0° to 45° and 315° to 360°). , second divided signal SD
2 rises to the "H" level corresponding to the linear approximation area LIN2 (that is, the section of the absolute rotation angle of 45° to 135°) of the maximum detection signal S20, and the third divided signal SD3 rises to the “H” level corresponding to the linear approximation area LIN2 of the maximum detection signal S20. Corresponding to LIN3 (i.e. absolute rotation angle range 135° to 225°),
The fourth divided signal SD4 rises to the "H" level corresponding to the linear approximation region LIN4 (that is, the section of the absolute rotation angle 225° to 315°) of the maximum detection signal S20.
“Stand up to the level.

Therefore, the rotational position detection circuit 32 determines that when the first divided signal SD1 is at the "H" level, the rotational position of the rotor magnet is within the absolute rotational angle of 0° to 45° or 315°.
It is determined that the rotation angle is in the range of 360° to 360°, and furthermore, the minute rotation angle in the range is detected based on the signal level of the linear approximation region LIN1 of the maximum detection signal S20.

Further, when the second divided signal SD2 is at the "H" level, the rotational position detection circuit 32 determines that the rotational position of the rotor magnet is in the absolute rotational angle range of 45° to 135°, and further The minute rotation angle in the section is detected based on the signal level of the linear approximation region LIN2 of the maximum detection signal S20.

Further, the rotational position detection circuit 32 determines that the rotational position of the rotor magnet is within an absolute rotational angle of 135° to 225° when the third divided signal SD3 is between the “H” level.
Further, the minute rotation angle in this section is detected based on the signal level of the linear approximation region LIN3 of the maximum detection signal S20.

Further, the rotational position detection circuit 32 determines that the rotational position of the rotor magnet is within an absolute rotational angle of 225° to 315° when the fourth divided signal SD4 is between the “H” level.
Further, the minute rotation angle in this section is detected based on the signal level of the linear approximation region LIN4 of the maximum detection signal S20.

In this way, the rotational position detection circuit 32
The absolute rotational position of the rotor magnet is determined from 0° to 360° based on the 4-divided signals SD1, SD2, SD3, and SD4.
By determining the rough position in which section is divided into four sections, and determining the minute position within the section using the maximum detection signal S20, it is expressed by the signal level of the maximum detection signal S20. The rotational position detection signal S30 indicating the absolute rotational angle of the rotor magnet can thereby be obtained.

The above has described the case where the absolute rotation angle is detected during one rotation of the rotor magnet, but a similar sine wave signal S(
By obtaining the inverted sine wave signal S (-SIN), the inverted sine wave signal S (-SIN), the inverted cosine wave signal S (-COS), and the divided signals SD1, SD2, SD3, and SD4, the absolute rotation angle is 0°. A rotational position detection signal S30 corresponding to ~360° can be obtained.

According to the above configuration, the sine wave signal S (SIN), cosine wave signal S (COS), and inverted sine wave signal S (-SIN) obtained by the Hall elements HE1 and HE2.
and the linear approximation region LI of the inverted cosine wave signal S (-COS)
By using N1, LIN2, LIN3, and LIN4, the absolute rotation angle can be detected using the maximum detection signal S20 whose signal level changes linearly in accordance with changes in the absolute rotation angle.

Therefore, it is possible to avoid a decrease in the detection resolution of the rotational position depending on the rotation angle as in the prior art, and it is possible to stably detect the absolute amount of the rotation angle of the rotating body with high resolution.

[0057] In the above embodiment, a case has been described in which the absolute rotation angle of the rotor magnet is detected using the maximum detection signal S20, but the present invention is not limited to this, and the inverted signal of the maximum detection signal S20 is used. The key point is to use the sine wave signal S (S
IN), inverted sine wave signal S (-SIN), cosine wave signal S
(COS) and the inverted cosine wave signal S(-COS) may be detected using a linear approximation region.

Furthermore, in the above embodiment, the case where the Hall element was used for detecting the rotational position was described;
The present invention is not limited to this, and may be used for both driving and rotational position detection.

Further, in the above-described embodiment, a case has been described in which a Hall element is used as the rotation detecting element, but the present invention is not limited to this, and other elements such as a magnetoresistive element can be applied.

Further, in the above-described embodiment, the case where the present invention is applied to a rotational position detection device for a brushless motor is described, but the present invention is not limited to this, but can be applied to rotational position detection devices for various other rotating bodies. Can be widely applied.

[0061]

As described above, according to the present invention, a sine wave signal, an inverted sine wave signal obtained by inverting the sine wave signal, a cosine wave signal, and the cosine wave are generated based on the rotational movement of a predetermined rotating body. Generate an inverted cosine wave signal by inverting the signal, obtain linear approximation signals formed by linear approximation regions of each of these four signals, and further generate the sine wave signal,
By comparing the signal levels of the inverted sine wave signal, cosine wave signal, and inverted cosine wave signal, a division signal is obtained that divides the absolute rotation angle of the rotating body into each of the above-mentioned linear approximation regions, and a division signal is obtained that divides the absolute rotation angle of the rotating body into the above-mentioned linear approximation regions. By detecting the absolute rotational position based on the linear approximation signal that changes linearly and minutely represents the rotational position, and the divided signal that roughly specifies the area of rotational angle represented by the linear approximation signal, The rotational position of can be detected linearly and minutely. In this way, a more stable and high-resolution rotational position detection device can be realized.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing an embodiment of a rotational position detection device according to the present invention.

FIG. 2 is a signal waveform diagram illustrating generation of a maximum detection signal according to the present invention.

FIG. 3 is a signal waveform diagram illustrating generation of a rotation angle dividing signal into four parts according to the present invention.

FIG. 4 is a block diagram showing the configuration of a rotation angle dividing circuit into four parts.

FIG. 5 is a signal waveform diagram for explaining conventional problems.

[Explanation of symbols]

10...Rotational position detection device, 11, 12, 13, 14...
... Comparison circuit, 21, 22 ... Minimum detection circuit, 23 ... Maximum detection circuit, 30 ... Rotation angle 4 division circuit, 32 ... Rotation position detection circuit, HE1, HE2 ... Hall element, S (S
IN)...Sine wave signal, S(-SIN)...Inverted sine wave signal, S(COS)...Cosine wave signal, S(-COS)...
...Inverted cosine wave signal, S16, S17... Minimum detection signal,
S20...Maximum detection signal, SD1, SD2, SD3, S
D4...Divided signal, S30... Rotational position detection signal.

Claims (1)

[Claims] 1. A rotational position detection device for detecting the rotational position of a rotating body using a predetermined rotation detection element, comprising: a sine wave signal generating means for generating a sine wave signal based on the rotational movement of the rotating body; cosine wave signal generating means for generating a cosine wave signal based on the rotational motion of a rotating body; and an inverted sine wave signal for generating an inverted sine wave signal by inverting the sine wave signal based on the rotational motion of the rotating body. generating means; and inverted cosine wave signal generating means for generating an inverted cosine wave signal by inverting the cosine wave signal based on the rotational movement of the rotating body;
Linear approximation signal generating means for generating a linear approximation signal based on a linear approximation area of each waveform of the sine wave signal, the cosine wave signal, the inverted sine wave signal, and the inverted cosine wave signal; division signal generation means for dividing the rotation angle into each of the linear approximation regions, and detecting the absolute rotational position of the rotating body based on the linear approximation signal and the division signal generated by the division signal generation means. A rotational position detection device characterized by: