JPH11341866A - Brushless motor drive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-priced brushless motor driver which can quickly detect the conditions of a motor, such as rotating direction thereof. SOLUTION: Since there is a pattern respectively in the rotations of the normal and reverse directions among the patterns, which change when the next edge is detected from the patterns of combination of communication sensor signals, in a case such that the edge detecting signal of the 1/6 period of the commutation sensor signal by sampling the existing commutation sensor signal in the sufficiently quick period, the current direction of rotation can be obtained through collation with the previously stored pattern, when the next edge detecting signal is obtained. Assuming the current pattern to be a pattern 3, the next pattern becomes either of the pattern 2 and pattern 4, and the rotating direction can be detected from the pattern obtained in the next edge detecting signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor driving device having a commutation sensor signal.

[0002]

2. Description of the Related Art In FIG. 3, a first signal and a second signal are pulse train signals having a phase difference of 90 electrical degrees obtained from a frequency signal generator mounted on a motor.

[0003] A first signal or a second signal is supplied in accordance with the rotation of the motor.
The rotation direction is detected by detecting the other level at the time of one rising (or falling) edge of the signal, and the level of the second signal with respect to the rising edge of the first signal is determined by the rotation of the motor. When the direction is the A direction, the level is L level, and when the direction is the B direction, the level is H level. Therefore,
The rotation direction is detected for each cycle of the frequency signal.

Further, the detected rotation direction is distinguished by displaying the polarity in the upper digit of a display having a 7-segment LED.

[0005]

In order to control the rotation speed of the brushless motor at high speed and with high accuracy, it is necessary to quickly detect the rotation direction and the rotation speed.

For this purpose, the cycle of the frequency signal must be sufficiently short with respect to the rotation of the motor. In a servo motor control device used for positioning control, etc.,
A rotary encoder capable of outputting thousands of pulses for one rotation of the motor is mounted on the motor. However, if a frequency signal generator capable of outputting thousands of pulses is mounted on a normal brushless motor drive device that only controls the rotation speed, it would be extremely expensive, the motor outer dimensions would be large, and it was not an effective means. .

In order to control a low rotation speed of about several tens of rotations including both forward and reverse rotations by using a commutation sensor signal which usually has only a few pulses per rotation of the motor, it takes time to detect the rotation direction. It was not possible to cope with speeding up.

An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive brushless motor driving device capable of quickly detecting a motor state such as a rotation direction.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an H level and an L level of a commutation signal.
Edge detection means for sampling the level and outputting a detection signal when any signal level changes, and storing a combination pattern of three commutation signal levels which can be generated for each rotation direction of the brushless motor. Means for comparing the combination pattern of the commutation signal level and the combination pattern of the storage means when the edge detection signal is output, and outputting a detection signal corresponding to the rotation direction in which the order of change matches The rotation direction detection means outputs a rotation direction detection signal every time an edge detection signal is input.

As a result, the detection speed in the rotational direction can be increased six times as compared with the related art.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention provides a method for detecting the rotational position of a rotor, each of which has an electrical angle of 12 degrees.
In a control device for a brushless motor having three commutation signals having a phase difference of 0 degree, an H level and an L level of the commutation signal are sampled and a detection signal is generated when any of the signal levels changes. An edge detecting means for outputting, a storing means for storing a combination pattern of three commutation signal levels which can be generated for each rotation direction of the brushless motor, and a combination pattern of the commutation signal when the edge detection signal is outputted And a combination pattern of the storage means, and a rotation direction detection means for outputting a detection signal corresponding to the rotation direction in which the change order matches.

The method according to claim 1, wherein the rotation direction detecting means outputs a rotation direction detection signal every time the edge detection signal is input.

Further, a means for comparing the combination pattern of the three sampled commutation signals with the combination pattern stored in the storage means and, if not applicable, deeming the sensor abnormal and interrupting the output to the brushless motor is further provided. The brushless motor driving method according to claim 1, further comprising:

2. The brushless motor driving method according to claim 1, further comprising an indicator comprising an LED of eight segments, and further comprising means for switching on and off of the dot segment of the LED by outputting a rotation direction detection signal. .

As described above, when the edge detection signal is output, the combination pattern of the commutation signal level is compared with the combination pattern of the storage means, and the detection signal corresponding to the rotation direction in which the order of change is coincident is output to rotate. The direction can be detected.

Further, since the rotation direction detection signal is output each time the edge detection signal is input, the rotation direction can be detected at a period 1/6 of the conventional one.

Further, when the pattern is different from the pattern stored in the storage means, it has a function of judging an abnormality, and the output to the brushless motor can be cut off.

Further, by outputting the rotation direction detection signal, the dot segments in the 8-segment LED can be switched on and off to display the rotation direction.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a CS signal generator 1 is a Hall IC, and each detecting a rotational position of a rotor has an electrical angle of one.
Three commutation signals CS having a phase difference of 20 degrees
1, CS2 and CS3 are output. Edge detection means 2
The H level and the L level of the commutation signals CS1, CS2, and CS3 are sampled, and an edge detection signal is output when any of the signal levels changes. At this time, the CS combination detecting means 3 detects a combination pattern of the commutation signals CS1, CS2, CS3. The CS combination storage means 4 is a storage means in which a combination pattern of the commutation signal level is stored in advance. The CS combination comparing unit 5 compares the combination pattern of the commutation signal with the combination pattern of the storage unit 4 when the edge detection signal is output. Then, the rotation direction detecting means 7 stores the CS in the storage means 4.
The rotation direction is detected from the change in the combination order, and a signal indicating the rotation direction is output to the dot segment lighting switching means 9. When the combination pattern of the detected CS signals is not in the CS combination order of the storage means 4, the sensor abnormality detection means 6 determines that the sensor is abnormal and the motor output cutoff means 8
Shuts off the output to the brushless motor.

In the above description, components other than the CS signal generator 1 are processed by the microcomputer. Next, how to use the detected commutation signal will be described. In FIG. 2, CS1, CS2, and CS3 are commutation sensor signals having a phase difference of 120 degrees. Here, each signal of the rising edge and the falling edge of each commutation sensor signal is six from pattern 1 to pattern 6. The order of the change of the pattern is, for example, in the rotation direction A, from pattern 1 to pattern 2 sequentially.
In the rotation direction B, the pattern changes from pattern 6 to pattern 5, pattern 4, pattern 3, pattern 2 and pattern 1 in reverse.

As described above, the conventional commutation sensor signal is sampled at a sufficiently fast cycle, and an edge detection signal having a 1/6 cycle of the commutation sensor signal is output. The pattern that will change when the next edge detection signal is obtained from the pattern of the combination of the commutation sensor signals when the edge detection signal is obtained is one in each of the forward rotation and the reverse rotation. When the detection signal is obtained, the current rotation direction can be obtained by comparing the detection signal with a pattern stored in advance. If the current pattern is pattern 3, the next pattern is either pattern 2 or pattern 4, and the rotation direction can be detected by the pattern obtained from the next edge detection signal.

Therefore, if the order of the two different types of pattern changes is stored in the microcomputer in advance and compared, the rotation direction can be determined. In addition, the rotation direction can be detected six times faster than the conventional rotation direction detection method.

Further, when the order of the pattern change does not match the stored pattern, it is determined that the mode is impossible with normal motor rotation, and a function to cut off the power supply to the motor is provided. Also, when the combination of the commutation sensor signal levels does not apply to any of the patterns 1 to 6, the power supply to the motor is similarly cut off (for example, all the H or L levels).

Further, by using the rotation direction detection signal output, the rotation direction display can be divided by switching the dot segment of the 8-segment LED of the display from on to off.

[0026]

As apparent from the above embodiment, claim 1
According to the described invention, the rotation direction can be detected at a higher speed than the conventional method using the commutation sensor signal, so that a more accurate control of the brushless motor can be realized.

According to the third aspect of the present invention, it is possible to easily detect an abnormal operation of the motor.

Thus, a brushless motor driving device capable of quickly detecting the motor state such as the rotation direction can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram of a commutation sensor signal showing an embodiment of the present invention.

FIG. 3 is a signal waveform diagram showing a conventional rotation direction detection method.

[Explanation of symbols]

 2 Edge detection means 4 CS combination storage means 7 Rotation direction detection means 8 Motor output cutoff means 9 Dot segment lighting switching means CS1, CS2, CS3 Commutation signal H, L signal level

Claims (4)

[Claims] 1. A control device for a brushless motor having three commutation signals each having a phase difference of 120 degrees in electrical angle for detecting the rotational position of a rotor, wherein the H level and the L level of the commutation signals are Edge detecting means for outputting a detection signal when a change occurs in any signal level by sampling; and storage means for storing a combination pattern of three commutation signal levels which can be generated for each rotation direction of the brushless motor. A rotation direction detection unit that compares a combination pattern of the commutation signal and a combination pattern of the storage unit when the edge detection signal is output, and outputs a detection signal corresponding to a rotation direction in which the order of change is identical; Brushless motor driving method provided with. 2. The brushless motor driving method according to claim 1, wherein the rotation direction detection means outputs a rotation direction detection signal every time the edge detection signal is input. 3. A means for comparing the combination pattern of the three sampled commutation signals with the combination pattern stored in the storage means, and if not applicable, deems that the sensor is abnormal and cuts off the output to the brushless motor. The brushless motor driving method according to claim 1, further comprising: 4. The brushless motor driving method according to claim 1, further comprising a display having an eight-segment LED, and further comprising means for switching on and off the dot segment of the LED based on a rotation direction detection signal output.