JPH08237986A - Rotational position detector and detecting method - Google Patents

Abstract

PURPOSE: To detect the rotational position continuously with high accuracy, even it a rotational speed detection element has a part of low accuracy, by estimating the rotational position based on an absolute rotational position and absolute rotational speed and acceleration determined from the absolute rotational position and then subjecting the estimated rotational position to interpolation. CONSTITUTION: An estimated rotational position/rotational speed detecting section 64 calculates an estimated rotational position S9 and an estimated rotational speed signal S10 based on an absolute rotational position signal S6, an absolute rotational speed signal S7 and an absolute rotational acceleration signal S8 calculated at an absolute rotational position/rotational acceleration calculating section 61 and a current time signal (t) delivered from a timer section 63. Based on the absolute rotational position signal S6, the absolute rotational speed signal S7, the estimated rotational position S9 and the estimated rotational speed signal S10, a rotational position/ rotational speed output section 65 calculates most appropriate rotational position signal S11 and rotational speed signal S12 which is then delivered to a motor drive section 66. With such arrangement, rotational position can be detected continuously with high accuracy even if the rotational speed detection element has a part of low accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational position detection device and a detection method, and is particularly suitable for detecting a rotational position of a drive motor for home electric appliances such as a washing machine, an air conditioner and a vacuum cleaner, or an industrial motor. The present invention relates to a simple rotational position detection device and detection method.

[0002]

2. Description of the Related Art Conventionally, a brushless motor inverter control system is generally a 120 ° energization system, which is a simple control method, but employs a 180 ° energization system which enables smoother motor drive in order to reduce vibration and noise. The demand to do so is high. However, the 180 ° energization method needs to detect the rotational position with higher accuracy than the 120 ° energization method. Therefore, generally, the rotational position is detected using an encoder.
It was necessary to increase the size of the rotary position detecting device by using an encoder for the 0 ° energizing rotary position detecting device.

Further, as a conventional method for detecting the rotational position of a brushless motor, the magnetic field of the rotor magnet is detected by using a rotational position detecting element such as a Hall element, so that the signal level changes according to the rotational position of the rotor magnet. There is a method of obtaining a rotational position detection signal to be used as a rotational position signal. In consideration of the defect of the rotational position detecting element in which the detection accuracy changes during one rotation cycle and sufficient detection accuracy cannot be obtained, as described in JP-A-4-295293, There has been proposed a technique for improving the detection accuracy of the rotational position by using the output of the rotational position detection element that produces a sine wave and a cosine wave, which has a better linearity.

It is also conceivable to directly use the commutation position signal, which is a digitized output of a Hall element or the like, which is used for switching the motor flow phase used in the 120 ° energization method of the brushless motor. In that case, the most accurate output of the rotational position signal of the Hall element or the like appears as the rising and falling edges of the digital signal, but the rotational position cannot be read at any other time.

In these cases, it is possible to estimate and complement the rotational position at the time when there is no signal accuracy or when there is no signal. As a method similar to that, Japanese Patent Laid-Open No. 5-328780
As described in Japanese Patent Laid-Open Publication No. 2003-242242, there is proposed a technique for estimating the rotational position at the time of output in consideration of the time from the input of the rotational position signal to the output of the three-phase voltage in AC servomotor control.

[0006]

However, in the technique described in Japanese Patent Laid-Open No. 4-295293, there is a circuit for processing the output signal of the rotational position detecting element in addition to using a plurality of rotational position detecting elements. Therefore, there is a problem that the circuit configuration becomes complicated. Further, the above-mentioned Japanese Patent Laid-Open No. 5-32
Since the technique described in Japanese Patent No. 8780 does not consider the acceleration / deceleration of the motor, there is a problem that an accurate rotational position cannot be estimated during acceleration / deceleration and continuous rotational position detection cannot be performed.

An object of the present invention is to solve the problems of these prior arts, with a simple circuit structure, even if the output of the rotational position detecting element has a portion with low rotational position accuracy.
An object of the present invention is to provide a rotational position detection device and a detection method that can perform complementary processing to detect rotational position with high accuracy and continuously.

[0008]

In order to achieve the above object, the present invention provides a rotational position detecting element portion for detecting a rotational position of a rotating body by a rotational position detecting element utilizing magnetic change, and the rotational position. In a rotational position detecting device having a detection signal generation unit that generates a rotational position detection signal based on the rotational position detection signal and a control unit that controls the rotational position detection based on the rotational position detection signal, the control unit is one of the rotating bodies. During rotation, in the part where the detection accuracy of the rotational position detection element is good,
The absolute rotational position is detected by directly detecting the rotational position, and in the portion where the detection accuracy is insufficient, the estimated rotational position is calculated by the absolute rotational position and the absolute rotational speed and the absolute rotational acceleration obtained from the absolute rotational position, A rotation position is continuously output using the absolute rotation position and the estimated rotation position.

Another feature of the present invention is that a rotational position detecting element step for detecting a rotational position of a rotating body by a rotational position detecting element utilizing a magnetic change, and a rotational position detection signal based on the rotational position. In a rotation position detection method having a detection signal generation step of generating and a control step of controlling the rotation position detection based on the rotation position detection signal, the control step includes one rotation of the rotating body,
In the portion with good detection accuracy of the rotational position detection element, the rotational position is directly detected to be the absolute rotational position, and in the portion with insufficient detection accuracy, the absolute rotational position and the absolute rotational speed obtained from the absolute rotational position. And calculating the estimated rotational position based on the absolute rotational acceleration and continuously outputting the rotational position using the absolute rotational position and the estimated rotational position.

[0010]

According to the present invention, the rotational position detecting element section detects the rotational position of the rotating body by using at least one rotational position detecting element. The output signal generation unit generates a rotational position detection signal based on the rotational movement of the rotating body. The absolute rotation position / rotational speed / rotational acceleration calculation unit of the control unit is
In the rotation, in a portion with high detection accuracy of the rotation position detecting element, the rotation position is directly detected to be an absolute rotation position, and the absolute rotation speed and the absolute rotation acceleration are calculated from the absolute rotation position.
The estimated rotational position / rotational speed calculation unit calculates the estimated rotational position from the absolute rotational position, the absolute rotational speed, and the absolute rotational acceleration in a portion where the detection accuracy is insufficient. The rotational position / rotational speed output unit complements the estimated rotational position and continuously outputs the rotational position using the absolute rotational position and the estimated rotational position.

As a result, the output of the rotational position detecting element is 1
Even if the rotational position accuracy changes during the rotation cycle and cannot be used practically, the portion with insufficient rotational position accuracy is estimated and compensated for. Detection can be performed.

Further, by driving the motor so that the rotational acceleration changes only when the absolute rotational position is detected, the estimated rotational position can be detected stably by reflecting the change in the rotational acceleration.

Further, when the rotation position detecting element has a means for generating one sinusoidal analog rotation position signal with respect to the rotation position of the rotating body, the rotation direction is set to the rotation direction command value of the rotating body or the like. It is possible to eliminate the fluctuation of the rotation position accuracy of the analog rotation position signal by using only the linear approximation part of the analog rotation position signal as the absolute rotation position information, and to make a continuous rotation position with high accuracy. Can be detected.

Further, when the rotation position detecting element has a means for generating three digital commutation position signals with respect to the rotation position of the rotating body, the commutation position detection edge of the digital commutation position signal is absolute. By using the rotation position information as the rotation position information, the rotation position information that is originally discontinuous is detected as the continuous rotation position, and the estimated position detection is performed without changing the circuit used in the 120 ° energization method of the brushless motor. 120 ° is energized in low-speed rotation with low accuracy, and 1 in high-speed rotation with high estimated position detection accuracy.
It can be used by switching to an appropriate operation method during motor operation, such as energizing at 80 °.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment and a second embodiment of a rotational position detecting device and a detecting method according to the present invention will be described below with reference to the drawings.

First, the first embodiment will be described.

FIG. 1 shows the overall structure of a brushless motor control device having a rotational position detecting device according to a first embodiment of the present invention. Brushless motor 4 and rotational position detector 5
a and an inverter device composed of an inverter device that operates according to a rotational position signal output from the rotational position detection device 5a, obtains a DC voltage Ed from an AC power supply 1 from a rectifier circuit 2 and a smoothing capacitor C, and supplies the DC voltage Ed to an inverter 3. To do.

This inverter 3 has transistors TR1 to TR1.
This is an inverter composed of TR6 and freewheeling diodes D1 to D6, and the AC output voltage is chopped by the positive potential side transistors TR1 to TR3 and the negative potential side transistors TR4 to TR6 of the DC voltage Ed undergoing pulse width modulation. It is controlled by operating.

The common emitter terminals of the transistors TR4 to TR6 and the common anode terminals of the freewheeling diodes D4 to D6 are connected to the GND side of the rectifier circuit 2 through the resistor R1.

The brushless motor 4 comprises a rotor 41 and a stator 42 in which armature windings U, V and W are inserted with a two-pole permanent magnet as a field, and a winding current flowing through the armature windings U, V and W. Flows through the resistor R1 and returns to the rectifier circuit 2.
By inserting the resistor R1 here, the current I1 can be detected by the voltage drop.

The rotational position detecting device 5a includes a rotational position detecting element portion for detecting the rotational position, for example, a hall element portion 51,
A detection signal generation unit that generates and adjusts a detection signal based on the output from the Hall element unit 51, for example, an operational amplifier unit 52,
A control unit for controlling the rotational position detection based on the signal adjusted by the operational amplifier unit 52, for example, the microcomputer 6
a.

The control circuit for controlling the rotation speed of the brushless motor 4 is provided in the microcomputer 6a. As signals input to the microcomputer 6a, the outputs S1 and S2 from the Hall element unit 51 that detects the rotational position of the rotor 41 are adjusted through the operational amplifier unit 52 to have a sinusoidal Hall element output signal S3 and the voltage of the resistor R1. Current I flowing from the drop signal S14 to the brushless motor 4
There is an overcurrent output signal S15 of the overcurrent detection circuit 8 which detects the overcurrent state of No. 1 and a rotation speed command signal S5 which gives a reference speed and a rotation direction to the microcomputer 6a from the outside of the brushless motor control device. The signal output from the microcomputer 6a is the drive output signal S13 to the driver circuit 7 that drives the transistors TR1 to TR6.

The overcurrent detection circuit 8 compares the current I1 with a preset reference current value by using a voltage drop signal S14 of the resistor R1 and compares the current I1 with a preset reference current value. Digital overcurrent signal S
15 is output.

In the microcomputer 6a, the rotational position detector 5a directly detects the absolute rotational position from the Hall element output signal S3 when the rotational position accuracy of the Hall element output signal S3 as the absolute rotational position information is good. At the time when the rotational position accuracy of the Hall element output signal S3 is insufficient, the estimated rotational position is obtained and complemented using the rotational speed and rotational acceleration obtained from the absolute rotational position.

FIG. 2 shows a functional configuration of the rotational position detecting device 5a shown in FIG.

The hall element portion 51 is the brushless motor 4
And outputs a signal that changes according to the rotational position of the permanent magnet rotor 41 as a potential difference between S1 and S2.

The operational amplifier section 52 outputs the output signals S1 and S2 of the hall element section 51 to A of the microcomputer 6a.
The sinusoidal Hall element output signal S3 that can be input to the / D converter is subjected to waveform gain adjustment and output.

The absolute rotational position / rotational speed / rotational acceleration calculating unit 61 inputs the Hall element output signal S3 from the operational amplifier unit 52 using an A / D converter, and further outputs the current time from a timer unit 63 which will be described later. Signal t and rotation direction determination unit 62
By using the rotation direction signal S4 from, the absolute rotation position signal S6, the absolute rotation speed signal S7, and the absolute rotation acceleration signal S8 are calculated and output.

The rotation direction discriminating unit 62 includes a rotation speed command signal S5 including a rotation direction command given from the outside of the brushless motor control device and an absolute rotation speed signal S7 from the absolute rotation position / rotation speed / rotation acceleration calculation unit 61. To output the rotation direction signal S4. Further, the rotation direction signal S4 is corrected by monitoring the waveform pattern of the Hall element output signal S3.

The timer section 63 counts up the timer counter at regular intervals. The value of this timer counter is output as the current time signal t.

The estimated rotational position / rotational speed calculation section 64 includes an absolute rotational position signal S6, an absolute rotational speed signal S7, an absolute rotational acceleration signal S8 and a timer section 63 obtained from the absolute rotational position / rotational speed / rotational acceleration calculation section 61. Estimated rotational position signal S9 and estimated rotational speed signal S1
0 is calculated and output.

The rotational position / rotational speed output unit 65 outputs the absolute rotational position signal S6 and the absolute rotational speed signal S7 obtained from the absolute rotational position / rotational speed / rotational acceleration calculation unit 61 and the estimated rotational position / rotational speed calculation unit 64. Obtained estimated rotational position signal S
9. Using the estimated rotational speed signal S10, the most appropriate rotational position signal S11 and rotational speed signal S12 are calculated and output to the motor drive unit 66. Also, the rotational position signal S to be output
Reference numeral 11 denotes an absolute rotational position / rotational speed / rotational acceleration calculation unit 6
It also outputs the absolute rotational position detection signal S16 used for determining whether the information is obtained from 1 or obtained from the estimated rotational position / rotational speed calculation unit 64.

The motor driving unit 66 drives the transistors TR1 to TR6 to drive the transistors TR1 to TR6 in order to rotate the brushless motor 4 at the rotation speed of the rotation speed command signal S5 provided from the outside of the brushless motor control device. Outputs S13. At that time, the rotation position
The rotation position signal S11 and the rotation speed signal S12 are input from the rotation speed output unit 65, and the rotor 4 is energized by 180 ° energization.
Although the drive output signal S13 corresponding to the actual rotational position and the rotational speed of 1 is output, if the rotational acceleration changes when the estimated rotational position is detected, the rotational acceleration change cannot be reflected and the correct rotational position can be detected. However, the motor current waveform may be disturbed. Therefore, the absolute rotational position detection signal S16
By changing the motor output only when the absolute rotational position is detected, the rotational acceleration is changed only when the absolute rotational position is detected, so that the estimated rotational position can be correctly reflected. When the brushless motor 4 is in the overcurrent state, this is detected by the overcurrent signal S15, and the process of stopping the operation of the brushless motor 4 is performed.

FIG. 3 shows a flow chart of the control procedure of the rotational position detection of FIG. The program for the control procedure of the rotational position detection is stored in advance in the memory (ROM) in the microcomputer 6a and is executed in parallel with the motor drive program by using the interrupt function or the like.

First, in step 10, the rotational position detection program is started, and then timer setting is started (11).
Here, the process for initializing the timer for knowing the current time t and then starting it is performed. Next, the functions related to the rotational position detection of the microcomputer 6a are initialized (1
2). Also, the rotation direction, absolute rotation position, absolute rotation speed,
It also performs initial detection of absolute rotational acceleration.

Next, the Hall element output signal S3 is read using the A / D converter and the Hall element output value is input (13). Then, the timer outputs the hall element output signal S3.
The time t at which is read is input (14).

Next, the read Hall element output signal S3
However, it is determined whether or not it is within the straight line approximation section d1 shown in FIG. 4A (15). Within the linear approximation section d1, that is, within the range in which the rotational position and the output of the Hall element output signal S3 are in proportion, the processing relating to the absolute rotational position described below is performed. In the case outside the section, that is, the rotational position and the Hall element output signal S3. If the output of is not in a proportional range, the process related to the estimated rotational position described later is performed.

In the processing of the absolute rotational position, it is necessary to first determine the rotational direction, so the rotational direction command value is input by inputting the rotational speed command value S5 including the rotational direction command from the motor drive program (16). Next, the rotation direction is determined using the rotation speed signal S7 obtained in the previous calculation, the rotation speed command value S5 including the rotation direction command, and the Hall element output signal S3 (17).

Next, including the Hall element output signal S3,
Previous calculation results S11, S12, S8 and rotation direction signal S
4 is used to calculate the absolute rotational position signal S6, the absolute rotational speed signal S7, and the absolute rotational acceleration signal S8 (18).

Next, in the conditional branch of step 15,
If the Hall element output signal S3 is outside the linear approximation section d1, the estimated rotational position / rotational speed is calculated (1
9). Here, the estimated rotational position signal S9 and the estimated rotational speed signal S10 at the current time t are calculated using the absolute rotational position signal S6, the absolute rotational speed signal S7, and the absolute rotational acceleration signal S8 calculated in step 18.

Next, the rotational position signal and rotational speed signal calculated in step 18 or step 19 are output to the motor drive program etc. as the most appropriate rotational position signal S11 and rotational speed signal S12 (20). After the processing of step 20 is completed, the processing from step 13 to step 19 is repeatedly executed to continuously detect the rotational position.

FIG. 4 shows a signal waveform in the process of generating the rotational position signal of the rotational position detecting device 5a of FIG.

(A) shows the waveform of the Hall element output signal S3. The Hall element output signal S3 is applied to the rotor 4 as shown in the figure.
Although a sinusoidal waveform is obtained according to the rotation position of 1, the change in S3 is small with respect to the change of the rotation position in the broken line portion.
The signal of S3 contains almost no rotational position information. Therefore, in the present invention, the linear approximation section d1 indicated by a solid line in which the change of the signal of S3 can be linearly approximated to the change of the rotational position, that is, the rotational position and the output of the Hall element output signal S3 are in a proportional range, The absolute rotational position is detected using the signal, and in the other broken line portions, that is, in the range where the rotational position and the output of the Hall element output signal S3 are not proportional,
This is complemented by calculating the estimated rotational position from the rotational speed and rotational acceleration obtained in the d1 section without directly detecting the rotational position. The estimated rotational position is calculated by adding the absolute rotational position and the rotational position calculated by multiplying the absolute rotational acceleration and the absolute rotational speed by the time coefficient. Also, the broken line portion t
Each of 1 to t15 indicates a switching point of the detection method.

(B) is a waveform of the rotational position signal S11. This is output as a rotational position signal to the motor drive unit 66 and the like. Further, here, the motor is assumed to rotate at a constant acceleration in the section of d2 and to rotate at a constant speed at other times, and the motor is driven so as to change the rotational acceleration only when the absolute rotational position is detected. The change is correctly reflected in the estimated rotational position detection.

(C) is the waveform of the rotation speed signal S12. This is output to the motor drive unit 66 and the like together with the rotational position signal S11, and is also used for calculation of the estimated rotational position signal S9.

(D) is the waveform of the rotational acceleration signal S8. This is the estimated rotational position signal S9 and the rotational speed signal S1.
It is used for the estimation calculation of 0.

By performing the rotational position detection as described above,
Even if only one Hall element is used, a motor drive that requires highly accurate rotational position detection, such as the brushless motor 180 ° energization method, must be realized with a very simple circuit configuration. You can

Next, the second embodiment will be described.

FIG. 5 shows the overall structure of a brushless motor control device having a rotational position detecting device according to the second embodiment of the present invention. This brushless motor control device has almost the same configuration as the brushless motor control device of the first embodiment of FIG. 1, but the rotational position detection device 5b is different, that is,
A rotational position detecting element unit for detecting the rotational position of the brushless motor 4 of the rotational position detecting device 5b, for example, the Hall element unit 5
4 and a detection signal generation unit that generates a detection signal based on the output from the Hall element unit 51, compares the signals, and digitizes them, for example, a commutation position signal generation unit 55 and a control unit that drives a motor, for example, a microcomputer. The operation algorithm of 6b is different. Here, the parts having the same reference numerals as those in FIG.
The same operation as in FIG. 1 is performed.

The control circuit for controlling the rotation speed of the brushless motor 4 is provided in the microcomputer 6b. As signals input to the microcomputer 6b, Hall elements 54a, 54b, 54 for detecting rotational positions of three positions of the rotor 41 which are deviated by 120 ° in electrical angle.
Outputs S20 to S25 from the Hall element unit 54 composed of c
The commutation position signals S26 to S28 output from the commutation position signal generation unit 55 as the digital commutation position signal for energizing 120 °, and the current I1 flowing to the brushless motor 4 from the voltage drop signal S14 of the resistor R1. Overcurrent output signal S15 from the overcurrent detection circuit 8 for detecting the overcurrent state of
There is a rotation speed command signal S5 which gives a reference speed to the microcomputer 6b from the outside of the brushless motor control device. The signal output from the microcomputer 6b is the drive output signal S13 to the driver circuit 7 that drives the transistors TR1 to TR6.

FIG. 6 shows a functional configuration of the rotational position detecting device 5a shown in FIG.

The hall element section 54 includes three hall elements 5
4a, 54b, 54c are attached to the rotational position of the permanent magnet rotor 41 at an electrical angle of 120 °. The Hall element portion 54 is connected between S20 and S21 and S2.
A signal that changes according to the rotational position of the permanent magnet rotor 41 is output as a potential difference between 2 and S23 and between S24 and S25.

The commutation position signal generation unit 55 digitizes the output signals S20 to S25 of the Hall element unit 54 by a comparator and outputs them as commutation position signals S26 to S28 when the motor is driven by 120 ° energization type. .

The absolute rotational position detector 67 receives the commutation position signals S26 to S28 from the commutation position signal generator 55 and further uses the current time signal t from the timer 63 to determine the absolute rotational position. The signal S29 is calculated and output.

The rotation speed / rotational acceleration calculation unit 68 calculates an absolute rotation speed signal S7 and an absolute rotation acceleration signal S8 from the absolute rotation position signal S29 from the absolute rotation position detection unit 67 and the current time signal t from the timer unit 63. Output.

The motor drive unit 69 may be the same as that of FIG. 2 of the first embodiment, but in the second embodiment, it is particularly 120 °.
Since it is the same as the hardware circuit for energization, the characteristic may be used to switch between 120 ° energization at low speed rotation and 180 ° energization method which is a more efficient control method at high speed rotation. In that case, the motor drive unit 69 uses the commutation position signals S26 to S in the 120 ° energization method.
28 is used to output a 120 ° drive signal S13, and at 180 ° energization, a 180 ° drive signal is output using the rotational position signal S11 and the rotational speed signal S12 from the rotational position detection device according to the second embodiment of the present invention. Is output to drive the brushless motor 4.

FIG. 7 shows a flowchart of the control procedure of the rotational position detection of FIG. The program for the control procedure of the rotational position detection is stored in advance in the memory (ROM) in the microcomputer 6b and is executed in parallel with the motor drive program by using the interrupt function or the like.

First, the rotational position detection program is started in step 30, and then timer setting is started (31).
Here, the timer for knowing the current time t is initialized and then started. Next, the function related to the rotational position detection of the microcomputer 6b is initialized (32). It also performs initial detection of the rotation direction, absolute rotation position, absolute rotation speed, and absolute rotation acceleration.

Next, the current time t is input from the timer (3
3). Next, using the already obtained absolute rotational position signal S29, absolute rotational speed signal S7, and absolute rotational acceleration signal S8, the estimated rotational position signal S9 and the estimated rotational speed signal S1 at the current time t are used.
Calculate 0 (34).

The signal level of any of the commutation position signals S26 to S28 changes from LOW to HIGH or HI.
When GH is changed to LOW, a process related to absolute rotation position detection is performed by the interrupt function. Hereinafter, a process related to the absolute rotational position detection will be described.

When the commutation position is detected (35), the time is first input (36). Here, the time t when this commutation position signal is detected is input from the timer. Next, the change in the commutation position signal is analyzed to obtain the absolute rotation position signal S29 (3
7).

Next, using the current absolute rotation position signal S29 and time t, and the absolute rotation position signal S29, absolute rotation speed signal S7, and absolute rotation acceleration signal S8 obtained by previous absolute rotation position detection, Absolute rotation speed signal S7 of
The absolute rotational acceleration signal S8 is calculated (38).

The rotational position and rotational speed thus obtained are the most appropriate rotational position signal S11 and rotational speed signal S.
12 is output to a motor drive program or the like (3
9).

After the process of step 39 is completed, the processes of step 33, step 34, and step 39 are repeated, and when the commutation position signal is input, the process relating to the absolute rotational position detection starting from step 35 is performed.

FIG. 8 shows a signal waveform in the process of generating the rotational position signal of the rotational position detecting device 5b of FIG. In addition,
It is assumed that the motor is rotating at a constant acceleration in the section of d2 as in the first embodiment, and is rotating at a constant speed at other time points.

(A) to (c) are commutation position signals S26 to S28, respectively. Commutation position signals S26 to S28
Are the comparators 55a to 5 of the commutation position signal generator 55.
Since it is digitized by 5c, it becomes a rectangular wave as shown in the figure. Further, t20 to t42 indicate the time points when the commutation position signal changes and the absolute rotational position is detected.

(D) is the waveform of the rotational position signal S11. This is output as a rotational position signal to the motor drive unit 69 and the like. Since the estimation complementing process is performed at almost all times, it may become discontinuous with the commutation position detection, but if it is constant acceleration rotation, accurate rotation position detection will be performed with a slight delay.

(E) is the waveform of the rotation speed signal S12. This is output to the motor drive unit 69 and the like together with the rotational position signal S11, and is also used for calculation of the estimated rotational position signal S9.

(F) is the waveform of the rotational acceleration signal S8. This is used for estimation calculation of the rotational position signal S9 and the rotational speed signal S10.

By performing the rotational position detection as described above,
It is possible to detect the rotational position with high accuracy and continuously from the rotational position information which is originally discontinuous, and without changing the circuit used in the 120 ° energization method of the brushless motor, 120 ° at low speed rotation with low estimated rotational position detection accuracy. It can be used by switching to an appropriate operation mode during motor operation, such as energization and 180 ° energization in high-speed rotation where the estimated rotational position accuracy increases. Further, the phase of the motor drive signal can be freely changed to realize highly efficient motor drive.

The output signal S3 of the operational amplifier 5 shown in FIG. 1 is used in the first embodiment, and the output signals S26 to S28 of the comparators 54a to 54c shown in FIG. 5 are used in the second embodiment.
Although the case where the rotational position of the rotor 41 is detected while estimating the rotational position by using the above, the present invention is not limited to this, and a high-precision portion of the Hall element is used while using a signal that reduces the rotational position accuracy. The rotational position detection accuracy can be substantially maintained at a high accuracy by complementing the low-accuracy portion by using only.

Further, in the above embodiment, the case where the hall element is used as the rotational position detecting element has been described, but the present invention is not limited to this, and other elements such as a magnetoresistive element may be applied. Also, the number of Hall elements used is one in the first embodiment and three in the second embodiment, but in the first embodiment, another hall element is used to surely detect the rotation direction. In the second embodiment, as in the first embodiment, one Hall element is used so as to estimate the rotation direction as well, and various numbers of Hall elements to be used can be applied depending on the requirement of detection accuracy.

Further, in the above-mentioned embodiments, the case where the present invention is applied to the brushless motor control device has been described. However, the brushless motor, the air conditioner, the electric washing machine and the like having the rotation position detecting device of the present invention is used. By using the motor control device, it is possible to easily reduce vibration and noise. Further, the present invention is not limited to this, and can be widely applied to various other rotational position detecting devices for rotating bodies, and also to position measurement in drive control of a linearly moving power source such as a linear motor. You can

[0074]

According to the present invention, by using the output of the rotational position detecting element that changes based on the rotational movement of a predetermined rotating body, this rotational position detection accuracy changes during one rotation of the rotating body and is put into practical use. Even if it does not withstand, the rotation position is detected directly as the absolute rotation position in the part with high accuracy, and the estimated rotation position is calculated from the rotation speed and rotation acceleration obtained from the absolute rotation position in the part with insufficient accuracy. By complementing, substantially accurate rotation position detection can be realized with high accuracy. By performing such rotational position detection, a small and low-cost sensor such as a Hall element can be used without using a large and costly rotational position sensor such as an encoder. And cost reduction can be achieved.

When the rotation position detecting element has a means for generating one sinusoidal analog rotation position signal with respect to the rotation position of the rotating body, the rotation direction is determined from the rotation direction command value of the rotating body or the like. By determining and using only the linear approximation portion of the analog rotational position signal as the absolute rotational position information, it is possible to detect the rotational position continuously with high accuracy. By performing rotational position detection in this way, a motor that requires highly accurate rotational position detection, such as the 180 ° energization method of a brushless motor, with a very simple circuit configuration that uses only one Hall element or the like. Drive can be realized.

Further, by performing the motor driving so that the rotational acceleration is changed only when the absolute rotational position is detected, the estimated rotational position detection can be stabilized and the disturbance of the motor current waveform can be prevented.

Separately from this, when the rotation position detecting element has a means for generating three digital commutation position signals with respect to the rotation position of the rotating body, a commutation position detection edge of the digital commutation position signal is obtained. By using as the absolute rotational position information, the rotational position information that is originally discontinuous can be detected with high accuracy and continuously. By performing such rotational position detection, 120 ° at low speed rotation with low estimated rotational position detection accuracy without changing the circuit used in the 120 ° energization method of the brushless motor.
It can be used by switching to an appropriate operation mode during motor operation, such as energization and 180 ° energization in high-speed rotation where the estimated rotational position accuracy increases. Further, the phase of the motor drive signal can be freely changed to realize highly efficient motor drive.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a brushless motor control device having a rotational position detection device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a rotational position detection device 5a shown in FIG.

FIG. 3 is a flowchart of a control procedure of rotational position detection of FIG.

4 is a signal waveform diagram in the process of generating a rotational position signal of the rotational position detection device 5a of FIG.

FIG. 5 is an overall configuration diagram of a brushless motor control device having a rotational position detection device according to a second embodiment of the present invention.

6 is a block diagram showing a functional configuration of a rotational position detecting device 5a of FIG.

FIG. 7 is a flowchart of a control procedure of rotational position detection of FIG.

8 is a signal waveform diagram in the process of generating a rotational position signal of the rotational position detection device 5b of FIG.

[Explanation of symbols]

5a, 5b ... Rotational position detecting device, 51, 54 ... Hall element section, 52 ... Operational amplifier, 55 ... Commutation position signal generating section,
6a, 6b ... Microcomputer, 61 ... Absolute rotation position / rotational speed / rotational acceleration calculation unit, 62 ... Rotation direction determination unit, 63 ... Timer unit, 64 ... Estimated rotation position,
Rotation speed calculation unit, 65 ... Rotation position / rotation speed output unit,
66/69 ... Motor drive unit, 67 ... Absolute rotation position detection unit, 68 ... Rotation speed / rotation acceleration calculation unit

Claims (12)

[Claims] 1. A rotational position detecting element portion for detecting the rotational position of a rotating body by a rotational position detecting element utilizing magnetic change,
In a rotation position detection device having a detection signal generation unit that generates a rotation position detection signal based on the rotation position and a control unit that controls the rotation position detection based on the rotation position detection signal, the control unit is configured to rotate the rotation. In one rotation of the body, the rotation position detection element directly detects the rotation position in an area where the detection accuracy of the rotation position detection element is high, and the absolute rotation position and the absolute rotation position are detected in the area where the detection accuracy is insufficient. A rotation position detecting device, which calculates an estimated rotation position based on an absolute rotation speed and an absolute rotation acceleration obtained from the rotation position, and continuously outputs the rotation position using the absolute rotation position and the estimated rotation position. . 2. A rotational position detecting element section for detecting a rotational position of a rotating body by a rotational position detecting element utilizing magnetic change,
In a rotational position detection device having a detection signal generation unit that generates a rotational position detection signal based on the rotational position and a control unit that controls the rotational position detection based on the rotational position detection signal, the rotational position detection element unit is And at least one rotational position detecting element that detects a rotational position of the rotating body, wherein the detection signal generation unit generates a rotational position detection signal based on the rotational movement of the rotating body, and the control unit In one part of the rotation of the rotating body where the detection accuracy of the rotational position detecting element is high, the absolute rotational position and the absolute rotational speed are calculated by directly detecting the rotational position to determine the absolute rotational position. In the rotational position / rotational speed / rotational acceleration calculation unit and in the part where the detection accuracy is insufficient, the estimated rotational position is calculated by the absolute rotational position, the absolute rotational speed, and the absolute rotational acceleration. And the estimated rotational position and rotational speed calculation unit that calculates,
A rotation position detecting device comprising a rotation position / rotation speed output unit that complements the estimated rotation position and continuously outputs the rotation position using the absolute rotation position and the estimated rotation position. 3. A portion with high detection accuracy is a range in which the rotational position and an output of the rotational position detection signal are in proportion to each other, and a portion with insufficient detection accuracy is the portion with low detection accuracy. A rotational position detecting device, wherein the rotational position and the output of the rotational position detection signal are in a non-proportional range. 4. The estimated rotational position is calculated by adding the absolute rotational position and a rotational position calculated by multiplying the absolute rotational acceleration and the absolute rotational speed by a time coefficient. A rotational position detecting device characterized by the above. 5. The rotation position detecting element unit according to claim 1 or 2, wherein the rotation position detecting element unit detects a rotation position of the rotating body by one predetermined rotation position detecting element, and the detection signal generating unit is configured to detect the rotation position. A sine-wave rotational position detection signal that changes based on rotational movement of the body is generated, and the control unit uses only a linear approximation portion of the rotational position detection signal as information on the absolute rotational position. Position detection device. 6. The rotation position detecting element unit according to claim 1 or 2, wherein the rotation position detecting element unit detects a rotation position of the rotating body by three predetermined rotation position detecting elements, and the detection signal generating unit is configured to detect the rotation position. A rectangular wave-shaped digital commutation position signal is generated based on the rotational movement of the body, and the control unit uses a commutation position detection edge of the rotation position detection signal as information on the absolute rotation position. Position detection device. 7. The motor drive unit according to claim 1, wherein the control unit drives the motor so as to change the rotational acceleration only when the direct rotational position for calculating the absolute rotational position is detected. A rotational position detecting device having: 8. The rotation according to claim 1 or 2, wherein the control unit includes a rotation direction determination unit that is necessary for calculating the absolute rotation position and that determines a rotation direction of the rotating body. Position detection device. 9. A rotational position detecting element step of detecting a rotational position of a rotating body by a rotational position detecting element using magnetic change, and a detection signal generating step of generating a rotational position detection signal based on the rotational position. In a rotational position detecting method including a control step of controlling the rotational position detection based on the rotational position detection signal, the control step includes a portion with a high detection accuracy of the rotational position detection element in one rotation of the rotating body. Then, the rotational position is directly detected to be an absolute rotational position, and in a portion where the detection accuracy is insufficient, an estimated rotational position is calculated from the absolute rotational position and the absolute rotational speed and the absolute rotational acceleration obtained from the absolute rotational position. Then, the rotational position detection method is characterized in that the rotational position is continuously output using the absolute rotational position and the estimated rotational position. 10. A rotational position detecting element step of detecting a rotational position of a rotating body by a rotational position detecting element using a magnetic change, and a detection signal generating step of generating a rotational position detection signal based on the rotational position. In the rotational position detection method having a control step of controlling the rotational position detection based on the rotational position detection signal, the rotational position detection element step includes at least one rotational position detection element that detects a rotational position of the rotating body. Then, the detection signal generating step generates a rotational position detection signal based on the rotational movement of the rotating body, and the control step has high detection accuracy of the rotational position detecting element in one rotation of the rotating body. In the part, the absolute rotational position for directly detecting the rotational position to determine the absolute rotational position and calculating the absolute rotational speed and the absolute rotational acceleration from the absolute rotational position. A rotation speed / rotational acceleration calculation step, and an estimated rotation position / rotational speed calculation step of calculating an estimated rotation position based on the absolute rotation position, the absolute rotation speed, and the absolute rotation acceleration in a portion where the detection accuracy is insufficient. A rotation position detecting method comprising: a rotation position / rotation speed output step of complementing the estimated rotation position and continuously outputting the rotation position using the absolute rotation position and the estimated rotation position. 11. The part with high detection accuracy according to claim 9 or 10, is a range in which the rotational position and the output of the rotational position detection signal are proportional, and the part with insufficient detection accuracy is A rotational position detecting method, wherein the rotational position and the output of the rotational position detection signal are in a non-proportional range. 12. The estimated rotational position according to claim 9, wherein the estimated rotational position is calculated by adding the absolute rotational position and a rotational position calculated by multiplying the absolute rotational acceleration and the absolute rotational speed by a time coefficient. A rotational position detecting method characterized by the above.