JPS5950785A - Single-phase capacitor motor - Google Patents

Abstract

PURPOSE:To stably stop a single phase capacitor motor without reverse rotation in a short time by decreasing the gain of a brake pulse generator to the prescribed value when the rotating speed reaches the prescribed value or lower at the braking time and reducing the braking current amount. CONSTITUTION:When a speed set signal NR becomes zero at a time t1 so that a motor becomes a braking state and the output voltage if a comparison amplifier 3 is converted from positive to negative as A, a brake pulse generator 5 is operated instead of a drive pulse generator 4, and a brake current flows to the motor 8 as C through a brake control thyristor 7. When a motor speed is decelerated as D so as to reach the prescribed value at a time t2, the gain of the generator 5 decreases to the prescribed value by the output of a low speed time brake gain switching circuit 10 as E, and a low brake current of the magnitude which does not cause a defect such as a reverse rotation is flowed. When a motor 8 is stopped, the output of the amplifier 3 becomes zero, and any of the drive and brake currents does not flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a single-phase capacitor motor device capable of performing stable braking.

[Technical background of the invention and its problems]

In conventional single-phase capacitor motors, in order to eliminate the braking winding, the motor has a main winding, an auxiliary winding, a triac for drive control between the capacitor connection point and the power supply between these windings, and a triac for drive control. The main circuit includes a braking control thyristor between the power supply terminal of the triac and the connection point between the auxiliary winding and the capacitor. In order to obtain stable braking operation in this main circuit configuration, all control circuits are equipped with a low-speed braking pulse erasing circuit.

FIG. 1 is a block diagram showing an example of the configuration of this type of conventional control circuit. In the figure, the speed setter 1 outputs a signal NR corresponding to the desired speed, and the feedback amount regulator 2 outputs a signal NF corresponding to the rotation speed of one motor, and the difference between these two signals NR and NFO is The comparison amplifier 3 receives each signal NR.

A signal obtained by amplifying the difference in NF by a certain predetermined gain, for example, twice is output. Then, the drive pulse generator 4 or the brake pulse generator 5 operates according to the polarity of the output signal of the comparison amplifier 3, makes the drive control triac 6 or the brake control thyristor 7 conductive, and supplies voltage to the motor 8. do.

Now, let's consider, for example, the time of starting, and assume that the speed setting device 1 is set to N rotations. Then, speed setting device 1
outputs a signal NRI corresponding to N rotations. On the other hand, since the signal N F id from the feedback IT sub-grouper is the same, the input signal of the comparator amplifier 30 is the output signal NRI of the speed setter 1.
be equivalent to. Therefore, the output signal of the comparison amplifier 3 is KX
The signal has a magnitude of NRI and becomes a polarity signal for drive control, for example, a positive polarity signal. This signal activates the drive pulse generator 4, which applies a phase-controlled gate pulse to the drive control triac 6 to make it conductive, and at the same time supplies a controlled voltage to the motor 8 to rotate it. .

Further, a speed generator (not shown) is attached to the motor 8, and a signal corresponding to the number of rotations of the rotor is provided to the feedback amount regulator 2. The feedback amount regulator 2 adjusts the magnitude of the signal proportional to the rotational speed, and inputs the signal as a feedback signal NFI to the comparator amplifier 3:C. Then, the comparison amplifier 30
The input signal is (NR-NFI), and the drive control triac 6 is controlled to rotate the motor 8 at N rotations.

On the other hand, when the speed setter 1 is set to zero rotation while the motor 8 is rotating, the output signal NR of the speed setter 1
becomes zero, but the output signal of the feedback amount regulator 2 becomes a signal NFJ corresponding to the rotation speed. Therefore, the output signal of the comparator amplifier 3 has a magnitude of KXNFJ, and is a signal with a polarity for braking control that is opposite to the polarity for drive control during supermotion. This signal activates the braking pulse generator 5,
The phase of the braking control thyristor 7 is controlled to cause a braking current to flow through the motor 8 for braking.

By the way, in the above, when the triac 6 for drive control is turned off and the triac 6 for brake control is turned on, the motor 8
The rotation speed-torque characteristic of is a characteristic that generates braking torque as shown in Fig. 2, and from the braking torque characteristic in the same figure, when the motor 8 is in a non-negative direction, it will rotate in the opposite direction at NA rotation. I understand that. Further, when an alternating current generator is used as a speed generator for detecting the rotational speed of the motor 8, a voltage of the same polarity is generated regardless of whether the motor 8 rotates in the forward or reverse direction. Now, if we consider that the speed setting is zero and the motor 8 is rotated slightly in the opposite direction, the speed generator generates a voltage and as a result, the output of the feedback amount regulator 2 becomes larger than the output of the speed setter 1. The braking pulse generator 5 operates and the braking control thyristor 7 becomes conductive. When the thyristor 7 becomes conductive, a braking current flows, generating a torque that rotates in the opposite direction as shown in Figure 2, and the motor 8 continues to rotate in the opposite direction even though the speed setting is zero. Problems such as not being able to stop may occur.

Therefore, conventionally, as shown in FIG. 1, a low-speed braking pulse erasing circuit 9 is provided to erase the braking pulse at low speeds, put the braking control thyristor 7 in a non-conducting state, and cut the braking current. Efforts are being made to prevent such problems from occurring. However, in this type of motor, the braking current is cut at low speeds, so braking torque cannot be obtained until the vehicle comes to a complete stop, and the motor 8 rotates by inertia at low speeds.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to supply braking current to a stopped state and stabilize it in a short time without causing the problem of reverse rotation that occurs when the speed setting is zero. An object of the present invention is to provide a single-phase capacitor motor device capable of performing high-speed braking.

[Summary of the invention]

To achieve the above object, in the present invention, when the braking thyristor conducts in the above-mentioned device, that is, when the rotor rotation speed reaches a low rotation speed below a predetermined value during braking, the gain of the braking pulse generator is adjusted. It is characterized in that the amount of braking current is reduced by decreasing the amount of braking current to a certain value.

[Embodiments of the invention]

An embodiment of the present invention shown in the drawings will be described below.

FIG. 3 is a block diagram showing an example of the configuration of a control circuit in a single-phase capacitor motor device according to the present invention. In the figure, the same parts as in FIG. , only the different parts will be described here. That is, in FIG. 3, a low speed braking gain switching circuit 10 is provided in place of the low speed braking pulse erasing circuit 9 in FIG. 1, and the braking current amount is reduced by the output of this low speed braking gain switching circuit 10. This is what I did. That is, this low-speed braking gain switching circuit 10 inputs the output of the feedback amount regulator 2, and operates on the condition that the rotation speed of the rotor reaches a low rotation speed below a predetermined value when the braking control thyristor 7 is conductive. , which reduces the gain of the braking pulse generator 5 to a certain value.

Next, the operation of such a single-phase capacitor motor device will be described using FIG. 4.

In the figure, when the comparator amplifier 3 outputs a positive polarity voltage, the drive control triac 6 operates,
When a negative polarity voltage is output, the braking control thyristor 7 operates. At the same time, the magnitude of the driving current is proportional to the magnitude of the positive polarity voltage output of the comparison amplifier 3, as shown in Figure B, and the magnitude of the braking current is proportional to the magnitude of the negative polarity voltage output of the comparison amplifier 3, as shown in Figure C. Proportional to the magnitude of the voltage output.

Now, consider the braking condition. In FIG. 4, time 1. Assume that the speed setting signal NR becomes zero and a braking state is entered.

Then, the output of the comparator amplifier 3 changes from a positive polarity voltage to a negative polarity voltage as described above. Therefore, the current is switched from a driving current to a braking current. When the braking current flows, the speed of the motor 8 decreases as shown in the figure. When a certain speed is reached, for example at time t, the output of the low speed braking gain switching circuit 10 is sent out as shown in FIG. Using this output, before time t2, the braking current is controlled by the negative polarity voltage output of the comparator amplifier 3, whereas after time t, a low braking current is caused to flow. The magnitude of this low braking current is such that even if this low braking current flows when the motor 8 is in a stopped state, no rotation acceleration force is applied to the motor 8, that is, the above-mentioned problem of reverse rotation does not occur.

On the other hand, when the speed of the motor 8 is zero, that is, when the motor is stopped, the output of the comparator amplifier 3 becomes zero, so that the low braking current disappears, and therefore, when the motor 8 is stopped, neither the drive current nor the braking direct current flows. Furthermore, even if the motor 8 is rotated in the opposite direction from the load side, if it is within a certain speed range, a braking current will flow at the moment it is rotated, but because the braking current is large enough, rotational acceleration force for reverse rotation will occur. It will stop without doing so.

In this way, the main winding and the auxiliary winding, the capacitor connected between these windings, and the drive control triac 6 interposed between the connection point of the capacitor and the main winding and the power supply. , a braking control thyristor 7 interposed between the power supply terminal of the drive control triac 6 and the connection point between the capacitor and the auxiliary winding, and a feedback amount that outputs a voltage proportional to the rotation speed of the rotor. A regulator 2, a drive pulse generator 4 and a braking pulse generator that control the drive control triac 6 or the braking control thyristor 7 according to the difference between the rotation signal generated by the feedback regulator 2 and the speed setting value. 5 and the output of the feedback amount regulator 2 as input, and the braking pulse generator 5 is activated on the condition that the rotation speed of the rotor reaches a low rotation speed below a predetermined value when the braking control thyristor 7 is conductive. The single-phase capacitor motor device is equipped with a low-speed braking gain switching circuit 9 that reduces the gain to a certain value.

Therefore, in braking operation, up to a certain speed, the comparator amplifier 3
The braking current can be controlled by the output voltage of , a low braking current is passed from the speed lower than that to a stop, and a braking torque can be generated by passing some braking current during braking operation until the stopped state. It becomes possible to perform stable braking while preventing the occurrence of rotational problems.

It should be noted that the present invention is not limited to the above embodiments, but can be implemented in various forms without changing the gist thereof.

〔Effect of the invention〕

As explained above, according to the present invention, the gain of the braking pulse generator is reduced to a certain value on condition that the rotational speed of the rotor reaches a low rotational speed during braking to reduce the braking problem. Therefore, we have developed an extremely reliable single-phase capacitor motor that can conduct braking current until it stops and perform stable braking in a short period of time without causing the problem of reverse rotation that occurs when the speed setting is zero. The device can be attached.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a control circuit of a conventional single-phase capacitor motor, Fig. 2 is a diagram showing braking torque-rotational speed characteristics, Fig. 3 is a block diagram showing an embodiment of the invention, and Fig. 4 is a block diagram showing a control circuit of a conventional single-phase capacitor motor. The figure is a diagram for explaining the action in FIG. 3. 1... Speed setting device, 2... Return adjustment device, 3...
Comparison amplifier, 4... Drive pulse generator, 5... Braking pulse generator, 6... Triac for drive control, 7.
...Thyristor for braking control, 8...Motor, 10...
・Low speed braking gain switching circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 1 □, ~Sat) Korean invasion Figure 4

Claims (1)

[Claims] A main winding and an auxiliary winding, a capacitor connected between these windings, a triac for drive control interposed between the connection point of the capacitor and the main winding and the power supply, and a triac for drive control. A braking control thyristor interposed between the power supply terminal of the triac and the connection point between the capacitor and the auxiliary winding, a feedback ft regulator that outputs a voltage proportional to the rotation speed of the rotor, and the amount of feedback. A drive pulse generator and a split pulse generator that control the drive control triac or brake control thyristor according to the difference between the rotation signal generated by the regulator and the speed setting value, and the output of the feedback tm regulator. a low-speed braking gain switching circuit that takes as an input and reduces the gain of the braking pulse generator to a certain value on the condition that the rotational speed of the rotor reaches a low rotational speed below a predetermined value when the braking control thyristor is conductive; A single capacitor motor device comprising: