JPS6082092A - Starting method of motor - Google Patents

Abstract

PURPOSE:To prevent a motor from starting in the reverse direction by fixing a rotor at the prescribed position at the starting time of the motor and then starting the motor. CONSTITUTION:The rotated state of a rotor 11 is detected by a comparator 14 with the induced voltage generated at the stator windings 15, 16, 17 of nonenergized state by the rotation of the rotor 11 during the operation of a motor. Energizing timing to stator windings 15, 16, 17 is controlling by a timer process on the basis of the input of a controller 10 in the rotated state. The prescribed stator windings 15, 16, 17 are energized for the prescribed time at the starting time of the motor, the rotor 11 is fixed to the prescribed position, and started. Thus, the start of the motor can be stably performed irrespective of the stopping position of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling an electric motor having a magnetically rotating rotor, and particularly relates to a method of starting the same.

(B) Prior Art Motors with rotors that rotate with magnetism include, for example, motors with coils for forming magnetic poles in the rotor, motors with magnets embedded in the rotor, etc. Recently, they have been widely used as non-commutated DC motors with ferrite magnets attached to the rotor, AC servo starters, AC synchronous motors, etc.

In such motors, the rotor equipped with permanent magnets rotates and the stator windings are in a de-energized state, without using a pulse generating means for position detection such as a Hall element or a pulse generator to detect the position of the rotor. If the timing of energization of the stator windings is controlled based on the induced voltage generated, the induced vehicle pressure will not occur until the rotor rotates, so the rotor position will not be known and the motor cannot be started. there were.

Therefore, at startup, the timing of energization to the stator windings is controlled in accordance with the output of a separately installed low-frequency pulse excavator to start the rotor, and an induced voltage is generated in the stator windings. The switch was made to control the energization timing based on this induced voltage.

In this case, at the start of startup, the operation is similar to that of a synchronous motor that rotates at a low frequency, so depending on the size of the load (moment of inertia), the time it takes to reach stable rotation (rotation synchronized with the output of the pulse oscillator) may vary. It was something that would happen.

Also, when switching the energization to the stator windings in accordance with the output of the pulse oscillator in this way, the rotor may rotate in the opposite direction depending on the position of the rotor and the stator winding that is energized first. There was a case. In other words, based on Figures 1 to 9, (1) in Figure 1 is a single-phase AC power supply, (2) is a rectifier circuit, and the rectifier circuit is explained in detail. Although the configuration is not shown, it has a well-known thyristor bridge circuit, etc. (3) is a rectifier circuit (2
) is an inverter that generates a rotating magnetic field in the stator using the rectified direct current. This inverter (3)
The elements constituting the circuit may be thyristors or other switching elements as long as they can control switching in response to signals from a control circuit, which will be described later, but in the following explanation, six transistors (4) connected as shown in the figure will be used. ~(9)
will be shown and explained as a representative example. 00) is a control circuit that outputs a signal for controlling the firing of the transistors constituting the inverter (3) in a predetermined order, and the stator windings in a non-energized state when the rotor (11) rotates. (+5)
, α6), α7) and the resistance (1, 0
Comparator 04) compares the magnitude with the midpoint voltage generated by division of 3).
After the comparison is made, the output of this comparator (14) is input, and based on this input signal, timer processing (switching the energization to the stator winding after a complete timer time is calculated from the input of this input signal) is performed. After that, transistors (4) to (9)
The 0N-OFF state of stator winding 05), (
+6), which switches the energization to αη. Also, based on the output of this control circuit 0 (υ is comparator 04), a second
As shown in the figure, the transistors (4) to (9) are 0N-
The OFF state is sequentially switched according to the first to sixth modes (after the sixth mode, the mode shifts to the seventeenth mode). For example, in the first mode, if a control voltage is applied to each transistor so that transistors (4) and (8) are turned on and other transistors (5) to (7) and (9) are turned off, the pre-winding is fixed.
), Q6) to the terminal ([Jl → terminal (current flows in the direction of V1, and then in the second mode transistors (4), (9)
ON, other transistors (5) to (8) OFF"F
If each transistor is controlled so that fixed prewind #1
lu5) and αη in the direction of terminal ([]) → terminal (4), and in the third mode, transistors (5) and (9
) is controlled so that it is ONt and the others are OFF, a direct current flows through the fixed prewinding su6+ and Qη in the direction from the terminal (V) to the terminal opening direction. Similarly, from the third mode to the sixth mode, transistors (4) to (9) are sequentially controlled to fire as shown in FIG. 2, and the cycle of the first to sixth modes is repeated.

In this way, the stator winding (151, (16), α7)
When the K current flows, a rotating magnetic field is formed, so the rotor (
Iυ rotates and can continue operating as an electric motor.

In addition, such electric motors operate based on the induced voltage generated by the rotation of the rotor (ill), so when no induced voltage is generated (stopped), there are many strange things in the operation. - Such a tr-low power method was unable to start the motor. Therefore, at the time of starting, a separate low-frequency oscillator was provided, and the mode was switched according to the output of this oscillator, and the induced voltage was large enough to be detected. From the time the voltage was generated, control was switched to control by this control circuit OQ.

Since such control was performed, for example, the rotor Ql
When the motor is started when l stops at the position shown in Fig. 3, the ON-OFF state of transistors (4) to (9) becomes the first mode state, and the stator winding α5) , 06), when a current flows from the terminal (J) to the terminal (V), the rotor 0υ starts rotating clockwise.

Next, from the state of the second mode and 7, as shown in Fig. 4, when an intercurrent flows from the terminal αD to the terminal W, the stator winding 05), (171Vc occurs in the stator winding (15), (171). The attraction between the magnetic field and the magnetic poles of the rotor (11) is balanced and the rotation of the rotor 0υ stops.Note that this is when the moment of inertia of the load connected to the motor is small; Thick (・The case will be described later.

After this, the state enters the third mode, and as shown in Fig. 5, current flows from the terminal (V) to the terminal W in the stator windings Q6) and Q71, and current is generated in the stator windings Q6) and α7). The rotor (II) starts rotating counterclockwise due to the magnetic field. When the fourth mode is reached, the stator windings 0 (support), 0
In 5), a current flows from the terminal (V) to the terminal σ, and the rotor Uυ maintains counterclockwise rotation due to the magnetic field generated in the stator windings 0 and 06). Thereafter, even if the modes are sequentially switched to the fifth mode, the sixth mode, the first mode, etc., the rotor rotation can be maintained in the counterclockwise direction.

Next, when the moment of inertia of the load is large, the magnetic field energy given during startup in the first mode is large, and the energy during clockwise rotation is also large. Therefore, in the next second mode, the pre-winding is fixed by the rotation of the rotor υ.
An induced voltage is generated in (151, (17)) of the transistor (4
), (9) becomes smaller than at startup, so the energy of the magnetic field applied to the rotor αυ becomes smaller than the energy possessed by the rotor 0υ. Therefore, in the second mode, this rotor 01) does not stop but continues to rotate clockwise. When switching to the third mode in this state, as shown in Fig. 7, current flows from the stator winding (I6) to the terminal (■) to the terminal (for the α force) to the stator winding (α, etc.), α If the energy of the magnetic field generated by the force is greater than the energy possessed by the rotor 0D, the rotor (11
) can be switched counterclockwise. However, the rotor (■υ
When it switches to the 4th mode when it does not switch counterclockwise and maintains a stopped state or further clockwise rotation, as shown in Fig. 8, stator winding 05), Q61 has terminal (V) → terminal α.
Current flows to D and the rotor (11) maintains clockwise rotation due to the magnetic field generated in stator windings α9 and (16+).Next, even when switching to the 5th mode, it remains fixed as shown in Figure 9. The child windings 0 (G) and (17) have a current flowing to the terminal W-+ terminal ((J) and the rotor αD maintains clockwise rotation due to the magnetic field generated in the stator winding 0!51.07). In this way, the sixth
Even if the mode was switched sequentially from mode to mode 1, the clockwise rotation was maintained and the rotation was opposite to the normal direction of rotation.In this way, depending on the stop position on the rotor side, the motor may rotate in the opposite direction. was there. In addition, electric motors such as those mentioned above have been made smaller and have higher output, and can easily drive loads with a large moment of inertia.Therefore, there is a tendency for loads with a large moment of inertia to be used, and depending on the stopping position of the rotor Uυ, The probability of reverse rotation was increased.

(c) Purpose of the Invention In view of the above problems, the present invention provides a control method that prevents reverse rotation by fixing the stator in a predetermined position before starting the electric motor. be.

B) Structure of the Invention The present invention relates to an electric motor consisting of a rotor that rotates with magnetism, a stator that forms a rotating magnetic field for driving the rotor, and its windings. consists of a comparator that compares changes in the induced voltage generated by the rotor in the stator winding in a non-energized state, and a control circuit that controls the timing of energizing the stator winding using a timer process based on the output of this comparator. This control circuit ensures that the motor starts by energizing the specified stator windings for a certain period of time to fix the rotor in a predetermined position before starting the motor. This is what I did.

(E) Embodiment Below, embodiments of the present invention will be explained based on FIGS. 10 to 14. First, the electric motor, inverter (3), etc.
Since the same one as in the figure is used, the explanation will be omitted. Therefore, the difference from the conventional one lies in the control circuit (10). In the present invention, this control circuit 00) is composed of a microprocessor and its peripheral components, and its operation is performed based on the flowchart shown in FIG. That is, in Fig. 1O, when the power supply is connected, the transistor (6) first applies a force for a period of time (approximately 1 to 5C5eC, depending on the magnitude of the moment of inertia of the rotor and load).
)) is in ON state. In other words, as shown in Figure 11, stator winding 05) and (17) have terminals (5) → terminals (
A current flows to Ll), and a constant magnetic field is generated on the stator winding 05) and the 0D rotor type). Next, after 1 hour has passed (
Based on the output of the oscillator inside the i111 circuit α0), the energization pattern to the transistors (4) to (9) is sequentially switched from the first mode to the sixth mode as shown in FIG. In this way, based on the output of the oscillator, the rotor U
When υ rotates and the induced voltage generated in the de-energized stator winding exceeds a predetermined value, the stator winding (1!19, αe, coupled to the α force) is generated based on the output of the comparator α (a). This is normal operation in which the

When the electric motor is started using the control circuit (10) that operates in this way, (1) When the rotor 01) is in the position shown in Fig. 11, the transistor (6) (power is turned on). Then, current flows from terminal (4) to terminal ((1) in stator winding α7), and stator winding Q51. (17)
A constant magnetic field is generated on the rotor αυ side. This magnetic field and the magnetic poles of the rotor aυ attract each other to maintain the rotor aυ in a stopped state. ■, When the rotor Uυ is in the position shown in Fig. 12, the rotor (Ill is the stator winding < 151
．． (It rotates to the left due to the magnetic field generated at lη. At this time, due to the magnitude of the moment of inertia of the rotor Ql) and the load of the motor, the rotor αυ does not stop in the stable state shown in Figure 11, but is shown in Figure 13. It may rotate to such a position. At this time, the magnetic field generated in the stator winding u9, (17) prevents the rotor Uυ from rotating to the left, and at the same time, the magnetic field causes the rotor aυ to start rotating to the right. Therefore, this rotor I alternately rotates counterclockwise and clockwise due to the magnetic field generated by the stator winding (15) and the alpha force. Such a rotor 0υ
The vibration gradually decreases and stops at the position shown in FIG. Also, if the moment of inertia of the load is large, the rotor (if 111 does not stop in the state shown in Figure 13, this rotor Ql) will rotate counterclockwise several times, and then switch to clockwise rotation as the rotational energy of rotor 0υ decreases. After oscillating for several seconds, it stops at the position shown in FIG.

■, When the rotor aυ is in the position shown in FIG. 14, the rotor αυ is connected to the stator winding u! 19. First, it rotates to the right due to the magnetic field generated at an. After this, the stator winding Q51. (The rotor (II) vibrates due to the magnetic field generated at lη and stops at the position shown in FIG. 11.

As described above, the rotor aυ is set in a predetermined position by the magnetic field generated in the stator windings Q5) and (17), so the control circuit 0 (υ is the transistor (4) to (9) shown in FIG. When switching sequentially from the 1st mode to the 6th mode, the rotor (
II) starts to rotate counterclockwise due to the magnetic field generated in the stator winding (15+, (1G+, a7)).After this, when the induced voltage generated in the non-conducting stator winding exceeds a predetermined value, the above-mentioned As in the conventional example, normal operation is performed in which the timing of energization to the stator windings is switched using a signal based on this induced voltage.

(f) Effects of the invention As described above, the present invention includes a rotor that rotates with magnetism,
In an electric motor consisting of a stator and its stator windings that form a rotating magnetic field for driving the rotor, during operation of the motor, induction occurs in the non-energized stator windings due to the rotation of the rotor. The rotational state of the rotor is detected by voltage, and the timing of energization to the stator windings is controlled by timer processing based on the input of this rotational state, and when the motor is started, power is energized to a specified stator winding for a certain period of time. Since starting is started after the rotor is fixed at a predetermined position, the motor can be started stably regardless of the stop position of the rotor.

In other words, the stop position of the rotor can reliably prevent reverse rotation of the rotor, which has conventionally occurred.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the basic configuration of a non-commutated DC motor.
Fig. 2 is an explanatory diagram showing the ON state of the transistor shown in Fig. 1, and Figs. 3 to 9 are conventional explanatory diagrams showing the magnetic field generated in the stator winding and the position of the rotor shown in Fig. 1. , 410
The figure is a flow chart diagram showing the operation of the control circuit according to the embodiment of the present invention, and Figures 11 to 14 are explanatory diagrams of the present invention showing the magnetic field generated in the stator winding and the position of the rotor shown in Figure 1. It is. 00)...control circuit, Uυ...rotor, (1 block α61, α7)...stator winding. Fig. 2 Fig. 3 Fig. 4 Fig. 6 U Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 1O Fig. 11 Fig. QA12 Fig. 13 Fig. U Fig. 1

Claims (1)

[Claims] (1) In an electric motor consisting of a rotor that rotates with magnetism, a stator that forms a rotating magnetic field to drive the rotor, and its stator windings, the rotation occurs during operation of the electric motor. The rotating state of the rotor is detected by the induced voltage generated in the de-energized stator winding due to the rotation of the rotor, and the timing of energizing the stator winding is controlled by a timer process based on human power in this rotating state. A method for starting an electric motor, characterized in that when starting an electric motor, electricity is supplied to a predetermined stator winding for a certain period of time to fix the rotor at a predetermined position, and then starting is started.