JPS6271487A - Drive controller for dc motor - Google Patents

Abstract

PURPOSE:To determine the abnormality of revolution quickly and precisely, and to prevent the damage of a DC motor by stopping conduction to the DC motor when the number of revolution of a rotor reaches a set value or less. CONSTITUTION:A DC motor 1 has a rotor-position detecting means 2 detecting the position of a rotor. A revolution-number detecting means 3 is connected to the rotor-position detecting means 2. The revolution-number detecting means 3 detects the number of revolution of the DC motor 1. A comparison means 4 compares the number of revolution with a set value, and the comparison means 4 outputs a stopping signal to a control means 6 when the number of revolution reaches the set value or less, and a power condition to the DC motor 1 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a drive control device for a DC motor used, for example, in an electric fan whose rotational speed is variable, and in particular to a protection mechanism in the event of abnormal rotation. .

(b) Conventional technology As a protection mechanism in a drive control device for a DC motor,
JP-A No. 56-62035 discloses a device that protects the locked state by stopping the power supply to the DC motor when the back electromotive force of the DC motor falls below a predetermined level for a predetermined period of time or more. , or JP-A-57-779
A device that detects the stoppage of rotation of a motor by using a capacitor, as disclosed in Japanese Patent No. 68, is well known. Furthermore, there are devices that use temperature sensing elements such as bimetals, and fans that detect changes in the shape of guards etc. (Japanese Patent Publication No. 54-436
84@publication, Utility Model Publication No. 56-48952).

(c) Problems to be solved by the invention However, in devices that utilize back electromotive force, the back electromotive force may also vary due to variations in the motor windings, flux, etc., making it difficult to make accurate judgments. In the case of a device using a capacitor, there is a possibility that an error in rotation speed detection may occur due to changes in characteristics due to aging or temperature, such as the capacity of the capacitor, and there is a concern about long-term use. In addition, devices that use a temperature detection element have a long operating time, and may vary depending on the ambient temperature.Moreover, devices that detect capacitance changes may malfunction or may not come into contact with the guard when carrying them. However, there were problems such as the rotation stopped and the circuit configuration became complicated.

This invention has been made in view of the above circumstances, and provides a drive control device for a DC motor that can quickly and accurately determine when an abnormal rotation occurs and can stop the DC motor without damaging it when an abnormality occurs. This is what I am trying to do.

(d) Means for Solving Problems The configuration of the present invention is to drive a DC electric current vJt1, which includes a drive means for driving a DC motor having a rotor position detection means, and a control means for outputting a control signal to the drive means. In the control device, a rotation speed detection means detects the rotation speed of the rotor from a rotor position detection signal output from the rotor position detection means, and a rotation speed setting value at which the rotation speed signal output from the rotation speed detection means is normal. This is a drive control device for a DC motor, characterized in that it includes a comparison means for outputting a stop signal to the control means to stop energizing the DC motor in the following cases.

In FIG. 1, (1) is a DC motor, which is equipped with rotor position detection means (2) for detecting the position of the rotor. (
3) is a rotation speed detection means, which is connected to the rotor position detection means and detects the rotation speed of the rotor from the rotor position detection signal. (4) is a comparison means that compares the rotation speed signal from the rotation speed detection means (3) with a set value, and if it is less than the set value, the control means (6) stops energizing the DC motor (1). Outputs a stop signal to

(5) is a driving means.

(E) Function Since the present invention is constructed as described above, the rotation speed detection means (3) detects the rotation speed, and the comparison means (4) compares the rotation speed with a set value. If it is below, the comparison means (4) outputs a stop signal to the control means (6) to stop energizing the DC electric motor 111(1).

(F) EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following examples.

What is shown in FIGS. 2 to 5 is a drive control device (A
) is used for the electric fan (B), and the rotation speed detection means (3), the comparison means (4) J5 and the control means (6) are configured by a microcomputer.

The fan lit machine (B) consists of a printed circuit board (base (8) that houses the sword, and a support (9) that stands on the base (8)) in which the 8 drive control device (A) is installed. and a fan part (1υ) provided at the upper end of the support column (9) via a neck piece (g). In the inside thereof, there is an out-rotor type DC motor (motor) (1; fixed to the neck piece 00), a blower blade 051 provided on the boss part (14) fixed to the rotor (131), and a boss. The spinner (6) fixes the part (14).

As shown in FIGS. 4 and 5, the drive control device (A) has a configuration including a first microcomputer, a wind setting switch connected to the first microcomputer, and a second microcomputer. 0, drive circuit ■,
It consists of an output transistor circuit (21).

The first microcomputer 07) turns the motor ON/OFF in response to the mm setting switch (18) provided on the top surface of the base (8).
2? i') OD nF: Output to x-ta e.

The second microcomputer e has rotor position detection means (
2 are connected. The old second microcomputer is
When the motor ON control signal is received, 1/1 of the rotor 03)
Rotor position detection signal [J
I NPLIT), (V INPUT), (WI
N motor rotation signal (LIU 0U) corresponding to
T), (VLIOUT), (WU 0UT), (tJ
D 0UT), (VD OUT>(WD O'U
T) is output to the drive circuit. And the drive circuit head has each motor rotation signal (UU 0UT), (
VUOLIT), (WU 0UT), (UD 0U
T), <VD 0tJT), and (WD 0UT) are inverted and output to the output transistor circuit (21).

In addition, the second microcomputer simultaneously controls the rotor (1
3) A rotational speed signal of one pulse per rotation is output to the first microcomputer (171). A timing chart showing the mutual relationship of these signals is shown in FIG.

1 is a power supply circuit for a DC motor (1) and its drive control device (A).

In addition, in the above, the first microcomputer operates as the comparison means (4), and the second microcomputer operates as the rotation speed detection means (3) and the control means (6).
). Further, the drive circuit (2) and the output transistor circuit (31) constitute a drive means (5).

Next, the operation of this embodiment will be explained with reference to FIGS. 7 to 10.

To explain the software of the first microcomputer, the program consists of the main routine shown in FIG.
It consists of three routines: the internal interrupt routine shown in the figure, and the external interrupt routine shown in FIG. Here, the external interrupt routine is executed by the second microcomputer 0tll.
The internal interrupt lunitin is activated every time the falling part of the rotational speed signal from the ll is input, and the internal interrupt lunitin is activated at regular intervals by a timer inside the first microcomputer, regardless of the main routine and external interrupt routine. to start.

First, when the electric fan (B) is powered on, the inside of the first microcomputer rib is initialized (step 100). After this, key manual processing is performed (step 101), for example, pressing the Ill setting switch □□□ once will change the setting to ``1 Weak'', then pressing it once will change to ``Medium'', pressing it again will change to ``Strong'', and finally `` Activate it so that it is turned off.

When the air volume is set by operating the air volume setting switch ■, 8, the set I! 1ffi (notch) is determined (Step 102), a setting value corresponding to the air volume [a reference value for determining that the rotation of the DC motor (1) is abnormal) is set to Met (Step 103), (Step 104) ), (step 105). Here, the setting value for the air volume "weak" is Tt, "medium" is T2, and "strong" is T3. When the wind engine is set, a motor rotation ON signal is outputted from the first microcomputer to the second microcomputer a (step 106), and the machine waits for key human power again.

Next, the internal interrupt routine is activated at Jfl around trasec during execution of the main routine. If the DC motor (1) is stopped, there is no need to calculate the rotation speed, so first determine whether the DC motor (1) is rotating or not (step 107). If the setting is "off"), the process returns to the main routine without doing anything. On the other hand, if the DC electric machine (1) is rotating, to find the time for the rotor 031 to rotate,
The rotation number counter is incremented (+1) (step 108), and the rotation number of the rotor 03 is detected by determining the rotation time of the rotor 031. That is, it is determined whether the rotation number counter has overflowed or not (step 109), and if it has not overflowed, the process returns to the main routine. If the external interrupt does not occur before the next internal interrupt occurs, the internal interrupt will be interrupted again.
Steps 107 and 108 are executed. In this way, if an external interrupt does not occur and the rotation number counter is not over-puffed 0-L, as shown in Figure 10, the number of revolutions from the rise to fall of the rotation number signal of the second microcomputer e is one revolution. Therefore, 0 internal interrupts occur during this period, and the time T for one rotation is T-nt l1sec -...-(1-1)
The rotation speed is detected.

If the DC electric motor 1 (1) is in a stopped state from the beginning, there is no rotation speed signal, that is, the external interrupt routine is not activated by the fall of the rotation speed signal. Therefore, a rotation abnormality due to an external interrupt cannot be judged. Therefore, after incrementing the rotation number counter during an internal interrupt, it is determined whether the rotation number counter has overflowed (step 109). If the rotation number counter has overflowed, it is determined that the rotation is abnormal and the power supply to the DC motor (1) is stopped. A stop signal is output (step 110), and the process returns to step 100 of the main routine.

If the rotation number counter does not overflow and the fall of the rotation number signal is input, an external interrupt routine is activated. The external interrupt routine calculates the contents of the rotation number counter (T=n
t m5ec ) and the set value T1, T2, or T3 (I
tseC) (step 111), and if the content of the revolution counter T≧set value (T1.T2, T3),
Since the rotational speed of the DC motor (1) is lower than the reference value, it is determined to be abnormal and a stop double angle is output (step 112), the interrupt process is ended, and the process returns to the initial process of the main routine (step 100). Also, T<Ti, T2, T:
If it reaches t, the rotation is normal, so the rotation number counter is cleared in order to perform the next rotation number detection (step 113) and the process returns to the main routine.

In this example, the period from the fall of the rotational speed signal to the final fall of the rotational speed signal, that is, the time T required for one rotation of the DC motor (1) is measured and set individually according to each air volume. By comparing the set values TL, T2, and T3, if the rotation speed is lower than expected, it can be determined that there is an abnormality and the DC motor (1) can be stopped.
It becomes possible to bring the DC electric motor 1 (11) into a safe state. Furthermore, since the setting values (reference values) T1°T2 and Ta corresponding to each air volume setting can be set, more detailed safety measures can be taken.

(G) Effects of the Invention According to this invention, since rotation abnormality is checked for each rotation of the DC motor, when rotation abnormality occurs, the DC motor is quickly operated to stop energizing the DC motor. A drive control device for a DC motor that does not burn out the motor can be obtained. Also, by using a microcomputer,
This eliminates the need for an external circuit and simplifies the circuit configuration.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a partial vertical cross-sectional side view of an electric fan including an embodiment of the present invention, and Fig. 3 is a partial vertical cross-sectional side view of the 77-n portion of the electric fan. , FIG. 4 is a block diagram of an embodiment of the present invention, FIG. 5 is an electric circuit diagram, and FIG. 6 is a timing diagram showing the relationship among the rotor position detection signal, electric machine rotation signal, and rotation speed signal.
7, 8 and 9 are a flowchart of a main routine, a flowchart of an internal interrupt routine, a flowchart of an external interrupt routine, and a flowchart of an external interrupt routine, respectively, for explaining the program of the first microcomputer. FIG. 10 is an explanatory diagram for explaining the timing of internal interrupts. (1)...DC motor, ('2J...
Rotor position detection means, (3)...Rotation speed detection means, (4)...Comparison means, (5)...
・Drive means, (6)... Control means, T
1. T2, T3...Setting value, U INPU
T, V INPUT. W INPUT...Rotor position detection signal. Figure 2: Procedural amendment December 2, 1985 1. 41 indications 1985 Patent Application No. 209693 2 Title of invention Drive control device for DC motor 3 III with each 111 characteristics to be amended Patent Applicant Address 2-18 Keihan Hondori, Moriguchi City Name (188) Sanyo Electric Co., Ltd. Representative Kaoru Iue 4, Agent 530 Address 1-3 Quarter, 5-chome Nishitenma, Kita-ku, Osaka
From One Building,” he corrected.

Claims (1)

[Claims] 1. In a drive control device for a DC motor, which includes a drive means for driving a DC motor having a rotor position detection means, and a control means for outputting a control signal to the drive means, the rotor position output from the rotor position detection means is A rotation speed detection means detects the rotation speed of the rotor from a detection signal, and when the rotation speed signal outputted from the rotation speed detection means is less than a normal rotation speed setting value, the control means stops energizing the DC motor. 1. A drive control device for a DC motor, comprising: comparison means for outputting a stop signal for the purpose of the control.