JPH0424793Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) The present invention relates to a hunting prevention device for a control motor used to control the opening and closing of valves and dampers, and is particularly designed to prevent hunting of control motors driven at high speeds. It is suitable for the purpose of prevention.

(Prior Art) FIG. 2 is a circuit diagram showing a schematic configuration of a conventional control device for a control motor CM. The control motor CM is an electric actuator that was developed especially for small, low-torque applications, and it rotates, stops, and reverses a lever connected to the output shaft of a reversible motor M with a brake via a speed reducer. The opening and closing of valves and dampers is controlled according to the movement of this lever. The reversible motor M has power terminals MH and ML for forward rotation and reverse rotation, and a common power terminal MC.
When current is applied between terminals MH and MC, it rotates in the forward direction, and when electricity is applied between terminals ML and MC, it rotates in the opposite direction.

Conventionally, in order to control this type of control motor CM, the detected voltage obtained from the potentiometer FBP interlocked with the reversible motor M is compared with the control voltage set by the control voltage setting device VC,
A power supply controller SC controls the power supply terminals MH and ML for forward rotation and reverse rotation of the reversible motor M so that the voltage difference is below a predetermined value.

(Problems to be solved by the invention) In the above-mentioned conventional technology, the output shaft of the reversible motor M with a brake rotates several times due to inertia even after the energization is stopped, but the reduction ratio by the reduction gear When is large, the rotational speed of the lever is slow, so the extent to which the lever passes the target stop position due to inertia is negligible and no problem occurs. On the other hand, when the reduction ratio of the speed reducer is small, the rotational speed of the lever is high, so that the lever often passes the target stop position by a wide distance due to inertia and comes to a stop. For example, if the lever is rotated 90 degrees in 3 to 10 seconds, even if the power to the reversible motor M is stopped when the lever reaches the target stop position, the lever will rotate 1 to 2 degrees. Rotate further,
The lever will stop after passing slightly past the target stop position. Therefore, there is a problem in that the reversible motor M rotates in the opposite direction toward the target stop position again, causing a so-called hunting phenomenon. In order to prevent this kind of hunting phenomenon, it is sufficient to lower the gain of the energization controller SC, but
In this case, even if the lever deviates from the target stop position, the range (dead width) in which the reversible motor M does not operate becomes wider, resulting in a problem that control accuracy deteriorates.

The present invention was made in view of the above points, and its purpose is to prevent hunting due to inertia of the control motor in a control device for a control motor driven at high speed, without increasing the dead band. To provide a control motor hunting prevention device that can prevent hunting.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the control motor hunting prevention device according to the present invention, as shown in FIG. A reversible motor M with a brake having power terminals MH and ML, and a feedback potentiometer linked to the rotation of the reversible motor M.
a control motor CM comprising an FBP;
Control motor CM potentiometer FBP
The control voltage setter VC outputs the control voltage to be compared with the detected voltage from the potentiometer FBP, and the voltage difference between the detected voltage from the potentiometer FBP and the control voltage from the control voltage setter VC is below a predetermined value. , power terminal for forward rotation and reverse rotation depending on the polarity of the differential voltage.
In a control motor control device comprising an energization controller SC that controls energization of MH and ML, an energization detection element ( When detecting energization to the current transformers CT ₁ , CT ₂ ) and the power supply terminal MH for forward rotation, and the power supply terminal for reverse rotation
A voltage generator VG is provided, which generates a voltage output of opposite polarity in accordance with the detection output of the energization detection element when energization is detected to the ML, and stops generating the voltage output when energization is not detected. The voltage output is applied in a direction that cancels out the difference voltage between the detected voltage from the potentiometer FBP and the control voltage from the control voltage setter VC.

(Function) In the present invention, as mentioned above, the forward rotation power terminal MH and the reverse rotation power terminal ML of the reversible motor M
When each of the potentiometers is energized, the voltage generator VG generates voltage outputs of opposite polarity to each other, and the voltage output of the voltage generator VG is applied to the potentiometer.
Since the voltage is applied in a direction that cancels out the difference voltage between the detected voltage from the FBP and the control voltage from the control voltage setter VC, the reversible motor M is de-energized slightly before the target stop position. When the energization is stopped, the reversible motor M rotates by an amount determined by the inertial rotational force and the braking force of the brake, and then stops. If the voltage output of the voltage generator VG is adjusted to a voltage value obtained by converting this inertial rotation into the detection voltage of the potentiometer FBP, the reversible motor M will stop at the target stop position. Furthermore, when the reversible motor M is stopped, the energization detection element does not produce a detection output, so the voltage generator VG stops generating voltage. Therefore, the energization controller SC
, the reversible motor M is not energized again after it is stopped.

The differences in operation between the present invention and the conventional example are shown in Figure 3 a and b.
Explain using. First, FIG. 3b shows the operation of a conventional example for comparison and contrast with the present invention. Now, assume that the control motor CM rotates the damper at high speed from 0% opening to a set point (target stop position) of 50% opening. When the control voltage setter VC is operated to generate a control voltage corresponding to 50% opening, the potentiometer FBP
Since a voltage difference occurs between the detected voltage and the control voltage, the energization controller SC performs energization control in a direction in which this voltage difference becomes smaller. This causes the control motor CM to rotate, and the damper opening approaches the set point. The power supply to the control motor CM is stopped at the set point, but the damper rotates due to inertia to slightly increase the set point (for example, 1 to 2
%) Stop at the position you passed. Therefore, the control motor CM reversely rotates again toward the energization stop position, causing hunting.

On the other hand, FIG. 3a is an explanatory diagram of the operation of the present invention.
As before, let's assume that the control motor CM rotates the damper at high speed from the set point (target stop position) from 0% opening to 50% opening.In this case, the inertial rotation amount A of the control motor CM is set to 1. ~2%, the voltage generator VG generates a voltage according to the inertial rotation amount A while the reversible motor M is energized, and this voltage is divided by the detected voltage by the potentiometer FBP and the control voltage setting device VC. The voltage is applied in a direction that cancels out the voltage difference between the control voltage and the control voltage.Therefore, the control motor CM is de-energized 1 to 2% before the set point, and due to inertia rotation, the control motor CM is moved closer to the set point than the de-energized position. The control motor CM stops at a nearby position.When the control motor CM stops, the voltage generator VG stops generating voltage, so the control motor CM rotates in the opposite direction toward the position where energization is stopped, as in the conventional case. There's nothing to do.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 4 is a circuit diagram of one embodiment of the present invention, and FIG. 5 is a circuit diagram showing its usage state. The control unit CU includes a control voltage setting device VC,
Contains an energization controller SC. The control voltage setter VC is
The variable resistor VR divides the DC voltage to generate the desired control voltage. This control voltage is compared with the voltage at terminal _P2 by the energization controller SC, and the switch SW is controlled to reduce the voltage difference, thereby controlling the control motor CM to rotate forward, reverse, or stop.

The control motor CM has a built-in reversible motor M with a brake. A lever is connected to the output shaft of the reversible motor M via a speed reducer such as a speed reduction gear. Reversible motor M rotates forward, stops,
By rotating in reverse, the lever rotates forward, stops, and
It performs a reverse operation and controls the opening and closing of valves and dampers according to the movement of this lever. Reversible motor M
are the power terminals MH and ML for forward and reverse rotation.
and a common power supply terminal MC.
When current is applied between MH and MC, it rotates in the forward direction, and when electricity is applied between terminals ML and MC, it rotates in the opposite direction. potentiometer
The FBP consists of a variable resistor, and its rotating shaft is interlocked with the main shaft that drives the damper etc. via a gear.

The reversible motor M has first and second coils for creating a rotating magnetic field. When one coil is connected to the power line, the other coil is connected to the power line via capacitor Cm, and alternating currents with different phases flow through both coils, creating a rotating magnetic field. . Since the direction of rotation of the rotating magnetic field is opposite when the first coil is connected to the power line and when the second coil is connected to the power line, select the coil that will be connected to the power line. By doing so, it is possible to rotate the motor M in either the forward or reverse direction. The reversible motor M is equipped with a brake, so that the motor M stops relatively quickly when the current to the coil is cut off.

Control motor CM and control unit CU
An inertia preventer X including an energization detection element and a voltage generator VG is connected between. In this embodiment, a current transformer is used as the energization detection element.
CT ₁ and CT ₂ are used. control motor
When current is applied between the forward power supply terminal MH of the CM and the common power supply terminal MC, a detection output is generated on the secondary side of the current transformer _CT1 . This detection output is full-wave rectified by diode bridge DB ₁ and capacitor
It is smoothed at C ₀ to produce a DC voltage output. A diode is installed at the output end of the diode bridge DB ₁ .
Since D ₁ is connected with the polarity shown, the voltage across capacitor C ₀ cannot be greater than the forward drop voltage of diode D ₁ . Similarly,
When current is applied between the reverse power supply terminal ML and the common power supply terminal MC, a detection output is generated on the secondary side of the current transformer _CT2 . This detection output is full-wave rectified by a diode bridge DB ₂ and smoothed by a capacitor C ₀ to produce a DC voltage output. At the output of the diode bridge DB ₂ , a diode D ₂ is connected with the polarity shown, so that the capacitor
The voltage across C ₀ will never be greater than the forward drop voltage of diode D ₂ . Therefore, when the power supply terminal MH for forward rotation is energized and when the power supply terminal ML for reverse rotation is energized, voltages of opposite polarity are generated across the capacitor _C0 , and this voltage The size of diodes D ₁ , D ₂
It is a constant value regulated by the forward voltage drop of . The voltage generated across the capacitor C ₀ is divided by a series circuit of a resistor R ₀ and a variable resistor VR ₀ , and the control voltage by the control voltage setting device VC and the detection voltage by the potentiometer FBP are divided. It is applied in a direction that cancels out the differential voltage. The magnitude of the output voltage of the voltage generator VG is determined by the variable resistor depending on the reduction ratio of the control motor CM.
It is adjusted appropriately by operating VR ₀ , and the inertia preventer X shown in FIG. 4 can be used for various control motors CM. In the embodiment, the maximum output voltage of the voltage generator VG is, for example, 30 mV. This voltage is converted to the detection voltage of potentiometer FBP as follows:
Equivalent to 1.5% damper opening.

(Effect of the invention) As described above, in the present invention, when the power supply terminal for forward rotation and the power supply terminal for reverse rotation of the reversible motor are energized, the voltage generator generates voltage outputs of opposite polarity. and the voltage output of this voltage generator is applied in a direction that cancels out the voltage difference between the detected voltage from the potentiometer and the control voltage from the control voltage setter, so that the reversible motor reaches the target stop position. When the reversible motor stops, the voltage generator stops generating voltage, so the reversible motor stops at the energization stop position. It will not rotate in the opposite direction. Therefore, hunting of the reversible motor can be prevented without lowering the gain of the energization controller.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing the basic configuration of the present invention, Figure 2 is a circuit diagram showing the basic configuration of the present invention.
3A is an explanatory diagram of the operation of the present invention; FIG. 3B is an explanatory diagram of the operation of the conventional example; FIG. 4 is a circuit diagram showing an embodiment of the present invention; FIG. 5 is a circuit diagram showing the state of use of the same as above. MH is the power supply terminal for forward rotation, ML is the power supply terminal for reverse rotation, M is the reversible motor with brake, FBP is the potentiometer, CM is the control motor,
VC is the control voltage setter, SC is the energization controller, CT ₁ ,
CT ₂ is a current transformer and VG is a voltage generator.

Claims (1)

[Scope of utility model registration request] A control motor comprising a reversible motor with a brake having power terminals for forward rotation and reverse rotation, a feedback potentiometer linked to the rotation of the reversible motor, and detection from the potentiometer of the control motor. a control voltage setter that outputs a control voltage to be compared with the voltage;
Energization is performed to control the power supply terminals for forward rotation and reverse rotation according to the polarity of the differential voltage so that the differential voltage between the detected voltage from the potentiometer and the control voltage from the control voltage setting device is below a predetermined value. A control device for a control motor comprising a controller,
An energization detection element detects energization to each power terminal for forward rotation and reverse rotation of the control motor, and voltage outputs of opposite polarity are provided when detecting energization to the power terminal for forward rotation and energization to the power terminal for reverse rotation, respectively. and a voltage generator that generates a voltage output in response to the detection output of the energization detection element and stops generating the voltage output when energization is not detected, and the voltage output of the voltage generator is connected to the detection voltage from the potentiometer and the control voltage setting device. A hunting prevention device for a control motor, characterized in that a control motor is applied in a direction that cancels out a voltage difference between the control voltage and the control voltage.