JPH08205583A - Circuit for controlling rotational speed of fan motor - Google Patents

Abstract

PURPOSE: To obtain a control circuit for the rotational speed of a fan motor wherein its configuration is simple and the noise generated by the control of the motor is less. CONSTITUTION: In a control circuit for the rotational speed of a fan motor which performs the switchings of the current fed to the motor at controlling periods synchronized with the phase of a power supply voltage, a plurality of ON/OFF control elements 3, 4, 5 the two elements 4, 5 of which are connected respectively in series with current limiting elements 6, 7 are connected in parallel with each other, and are interposed between an AC power supply 1 and a fan motor 2. Further, by the use of the sensed phase of the power supply voltage through voltage-phase sensing means 9 for sensing the phase of the power supply voltage and by the use of control-timing generating means 10, the switchings of the plurality of ON/OFF control elements 3, 4, 5 are performed every integer times the half cycle of the power supply voltage. Thereby, when the current fed to the fan motor 2 is cut off, it is reduced step-wise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor rotation speed control circuit for controlling the rotation speed of a fan motor in order to obtain a required air volume.

[0002]

2. Description of the Related Art As a control circuit for controlling the rotation speed of a fan motor, for example, there is a control circuit for controlling a duty ratio as disclosed in Japanese Patent Publication No. 6-67276. This type of control circuit has a zero-cross detection circuit 101 for detecting a zero-cross signal of the power supply voltage as shown in FIG. 17, and a microcomputer 102 for obtaining a control pattern based on the signal of the zero-cross detection circuit 101. Based on the control pattern by the microcomputer 102, the current to the fan motor 103 is turned on / off by the triac 104.
It is configured to be controlled by turning it off. this is,
The number of ON / OFF cycles of the triac 104 is varied within the control cycle, which is an integral multiple of the power supply frequency, and the power supply to the fan motor 103 is controlled to control the rotation speed of the fan motor 103. The energization waveform of is as shown in D of FIG. 18A shows the voltage waveform of the power supply, B shows the input waveform of the microcomputer 102, and C shows the output waveform of the microcomputer 102.

In addition to this, as shown in FIG. 19, for example, the rotational speed of a motor is often controlled by phase control. Reference numeral 201 in FIG. 19 denotes a zero-crossing detection circuit composed of a diode bridge 202, a resistor 203, a constant voltage power source 204, and a voltage comparator 205.
Is a signal delay circuit capable of setting the delay time of the zero-cross signal by the voltage of the delay time setting means 207, and 208 is a triac inserted between the power source 209 and the motor 210. The delayed output of the signal delay circuit 206 is applied to the gate of the triac 208 via the gate drive resistor 211.

In this circuit, the power supply voltage shown in A of FIG. 20 is full-wave rectified by the diode bridge 202 as shown in B of FIG. 20, and compared with the voltage of the constant voltage power supply 204 by the voltage comparator 205. Power supply 209 shown in C of FIG.
The zero-cross detection signal is output from the zero-cross detection circuit 201. This detection signal is delayed by the delay time set by the delay time setting means 207 in the signal delay circuit 206, and the triac 2 is used as the drive signal shown in D of FIG.
It is output to 08. Triac 208 by drive signal
When is turned on, a voltage is applied to the motor 210, and FIG.
A current as shown by E flows in the motor 210. That is,
By changing the delay time by the delay time setting means 207, the current flowing to the motor 210 is adjusted, and the motor 2
The rotation speed of 10 is controlled.

[0005]

In the conventional control circuit for controlling the motor rotation speed as described above, a control circuit for controlling the energization rate as disclosed in Japanese Patent Publication No. 6-67276,
Since it is ON / OFF control that turns ON / OFF the triac 104 in the control cycle, there is a problem that torque fluctuations at the time of ON and OFF are steep, and noise easily occurs from the fan motor 103 itself. If the control cycle is multiplied by an odd number of half the cycle of the power supply voltage, the fan motor 10
Since magnetic noise is generated from 3, the control cycle is as long as an integral multiple of one cycle of the power supply voltage.
Since the rotation fluctuation range of the fan motor becomes large, there is a problem in that the pulsation of the wind noise of the fan and the noise due to the intermittent energization of the fan motor 103 become noticeable.

The problem of noise can be prevented by an inverter circuit which is controlled at a frequency higher than the power supply frequency because the rotational speed with less torque fluctuation can be controlled, but the inverter circuit has a complicated structure and high-speed switching. The cost is high because an element is also required.

On the other hand, in the above-mentioned phase control,
If the fan motor 210 is turned on at a time when the power supply voltage is high, the fan motor 210 will generate magnetic noise such as unpleasant metallic noise. If noise countermeasures are required, the fan motor 210 may be molded with resin. In addition, the fan motor 210 and the blades have to be floated with a cushioning material, and there is a problem that the cost for noise countermeasures is high, and those noise countermeasures are those in which the fan motor 210 is made of sheet metal. Compared to, it is difficult to reuse the material.

The present invention has been made in order to solve the above-mentioned conventional problems, and its object is to provide a fan having a simple structure and a low cost, which causes less noise from a fan motor due to control. To provide a motor rotation speed control circuit, to increase the applicability and adjustment function of the control circuit, and to suppress the generation of noise due to noise.

[0009]

In order to achieve the above object, the invention of claim 1 controls the rotation speed of the fan motor by turning on and off the electric current to the fan motor at a control cycle synchronized with the phase of the power supply voltage. In the control, a series circuit including a plurality of ON / OFF control elements and a current limiting element is connected in parallel between the AC power supply and the fan motor, and the plurality of ON / OFF control elements of these series circuits are inserted. , When the current to the fan motor is cut off by the control timing generation means from the phase of the power supply voltage detected by the voltage phase detection means for detecting the phase of the power supply voltage, it is switched to the fan motor every integer multiple of half cycle of the power supply voltage A means for gradually reducing the current is adopted.

In order to achieve the above object, the invention of claim 2 controls the rotation speed of the fan motor by turning on and off the current to the fan motor at a control cycle synchronized with the phase of the power supply voltage. A current limiting means capable of continuously controlling the amount of current is inserted between the power supply and the fan motor, and the current limiting means is controlled from the phase of the power supply voltage detected by the voltage phase detection means for detecting the phase of the power supply voltage. A means for controlling by the timing generating means to gradually reduce the current flowing to the fan motor when the current to the fan motor is cut off is adopted.

In order to achieve the above object, the invention of claim 3 uses the control timing generating means in the means according to claim 1 to perform half cycle of the power supply voltage at a certain phase of the power supply voltage when energizing the fan motor. A means for switching a plurality of ON / OFF control elements for each integral multiple and gradually increasing the current flowing to the fan motor is adopted.

In order to achieve the above-mentioned object, the invention of claim 4 is the means according to claim 2, wherein the control timing generating means controls the current limiting means from a certain phase of the power supply voltage when the energization of the fan motor is started. Then, a means for gradually increasing the current flowing to the fan motor is adopted.

In order to achieve the above object, the invention of claim 5 is, in addition to the means according to claim 1 or claim 2, a power-on phase setting means capable of arbitrarily setting a power-on phase of an AC power source. Adopt the means provided.

In order to achieve the above object, the invention of claim 6 is different from the means of claim 1 or 2 in that the power-on phase of the AC power supply can be set slightly before the zero cross of the AC power supply. A means including a power-on phase setting means is adopted.

In order to achieve the above object, the invention of claim 7 is independent of the means according to claim 1 or claim 2 and can set the power-on phase of the AC power source corresponding to the difference of the power source frequency. The means for switching the power-on phase setting means is provided.

In order to achieve the above-mentioned object, the invention of claim 8 can set the control timing generating means in the means according to claim 1 or 2 in multiple stages by the control notch setting means. In this way, a means for varying the control cycle according to the control notch is adopted.

In order to achieve the above object, the invention of claim 9 uses a single-phase capacitor motor as the fan motor in the means according to claim 1 or 2, and the main coil side of this capacitor motor is Multiple ON / OFF
A means for inserting a series circuit including a control element and a current limiting element in parallel connection or inserting a current limiting means capable of continuously controlling the amount of current is adopted.

[0018]

According to the first aspect of the present invention, when the rotation speed of the fan motor is controlled by turning on and off the current to the fan motor at a control cycle synchronized with the phase of the power supply voltage, the fan motor at the control cycle is controlled. ON / O for every integral multiple of half cycle of power supply voltage
The series circuit formed by the FF control element and the current limiting element is switched, and the current limiting element of the series circuit gradually reduces the current flowing to the fan motor, and the torque fluctuation when the current to the fan motor is cut off becomes gentle.

According to the second aspect of the present invention, when the rotation speed of the fan motor is controlled by turning on and off the electric current to the fan motor in a control cycle synchronized with the phase of the power supply voltage, the fan motor in the control cycle is controlled. When the current to the fan motor is cut off, the current flowing to the fan motor is gradually reduced by the current limiting means capable of continuously controlling the amount of current, and the torque fluctuation when the current to the fan motor is cut off becomes gentle.

According to the third aspect of the present invention, in addition to the operation according to the first aspect, at the time of starting the energization of the fan motor in the control cycle, a plurality of power supply voltages are provided at a certain phase for every integral multiple of half cycle of the power supply voltage. The ON / OFF control element is switched, the current flowing to the fan motor is increased stepwise by the current limiting element of the series circuit, and the torque fluctuation becomes moderate even when the energization of the fan motor is started.

In the means according to claim 4, in addition to the operation according to claim 2, the current flowing to the fan motor gradually increases from a certain phase of the power supply voltage when the energization of the fan motor is started in the control cycle. ,
The torque fluctuations are also moderate when the energization of the fan motor is started.

In the means according to claim 5, in addition to the operation according to claim 1 or 2,
The power-on phase setting means can adjust the power-on phase at which noise generated during control is further reduced according to the fan motor.

In the means according to claim 6, in addition to the operation according to claim 1 or 2,
Since the power-on phase setting means can set the power-on phase of the AC power source slightly before the zero crossing of the AC power source, even if noise is superimposed on the power source voltage due to the influence of the equipment used in the surroundings, the control timing generation means The output signal is
It is less likely to shift backwards from the zero cross of the AC power supply.

In the means according to claim 7, in addition to the operation according to claim 1 or 2,
By switching the power-on phase setting means according to the difference in the power-source frequency, the power-on phase of the AC power source can be optimized for the power-source frequency.

In the means according to claim 8, in addition to the operation according to claim 1 or 2,
Since the control cycle can be changed according to the multi-step control notch set by the control notch setting means, it is possible to select the control notch that generates less noise, and shorten the control cycle to reduce the rotation speed of the fan motor. The change in can be suppressed to a small level.

In the above-mentioned means according to claim 9, in addition to the operation according to claim 1 or 2,
Although the current of the main coil of the condenser motor is controlled, the current of the auxiliary coil is not controlled and is constant, the total current is the sum of them, and the current to be controlled can be reduced, and only the coil load can be controlled. Because of the control, the current change at power-on becomes gentle.

[0027]

An embodiment of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a circuit configuration diagram showing a rotation speed control circuit of a fan motor according to a first embodiment, and FIG. 2 is an explanatory diagram showing its operation timing. The fan motor rotation speed control circuit shown in FIG. 1 controls the rotation speed of the fan motor by turning on and off the current to the fan motor at a control cycle synchronized with the phase of the power supply voltage. Is connected to the fan motor 2 by a commercial power source. Between the commercial power source 1 and the fan motor 2, a current limiting circuit in which a plurality of series circuits including triacs 3, 4, 5 as ON / OFF control elements and resistors 6, 7 as current limiting elements are connected in parallel. 8 has been inserted. Between the terminals of the commercial power source 1, a voltage comparator 9 is connected as a voltage phase detecting means for detecting the phase of the power source voltage.

Reference numeral 10 is a microcomputer as a control timing generating means for generating a control timing from the phase of the power supply voltage. The output side of the voltage comparator 9 is connected to its input terminal, and the variable resistor 11 as the rotation speed setting means is provided. It is connected to the A / D conversion input terminal Q. The output terminal X of the microcomputer 10 is connected to the gate of the triac 3 of the series circuit via the gate drive resistor 12, and the output terminal Y is connected to the gate of the triac 4 of the other series circuit via the gate drive resistor 13. The output terminal Z is connected to the gate of the triac 5 of another series circuit via the gate drive resistor 14.

In the fan motor rotation speed control circuit having the above-described configuration, the microcomputer 10 turns on and off the electric current to the fan motor 2 at a control cycle in synchronization with the phase of the power supply voltage to control the rotation speed of the fan motor 2. Controlled. When the current to the fan motor 2 of this control cycle is cut off, the microcomputer 10 changes the phase of the power supply voltage in units of control phases # 1 to # 8 shown by J in FIG. Output terminals X, Y, Z
Switch the output from.

That is, the voltage comparator 9 detects the phase of the power supply voltage with respect to the power supply voltage of the waveform shown by A in FIG. 2 and outputs the detected phase shown by B in FIG. The microcomputer 10 to which the output of the voltage comparator 9 is input generates and outputs a drive pulse to the output terminals X, Y and Z at the timings C, D and E shown in FIG. The drive pulses output to the output terminals X, Y, and Z control ON / OFF of the triacs 3, 4, and 5 as indicated by F, G, and H in FIG. 2, respectively. No resistor is connected to the triac 3, but the triacs 4 and 5 have resistors 6 and 7 as current limiting elements, respectively.
Are connected in series, the current to the fan motor 2 is limited when the triac 4 or the triac 5 is ON, and the current waveform of the fan motor 2 is as shown in FIG.
As indicated by I, when the current to the fan motor 2 in the control cycle is cut off, its effective value is controlled and gradually decreases.

Therefore, the fan motor 2 has a simple structure.
The torque fluctuation when the current to the
Noise due to abrupt torque fluctuations when the power is cut off is reduced.
When the energization time is an odd number of half cycles of the power supply voltage, the noise generated tends to increase, but this point can also be improved by gradually reducing the current when the power is cut off. Further, since the control unit can be set to a half cycle of the power supply voltage and the control cycle can be shortened, it is possible to suppress the speed ripple of the fan motor 2 caused by turning the current ON / OFF. Further, since the control operation is not accompanied by the high-speed switching operation and is at a low speed, the occurrence of electrical noise is small. When the triacs 3, 4, and 5 are adopted as ON / OFF control elements, the operation may be a pulsed driving signal, so that not only the average driving current is required but also the triacs 3, 4, and 5. 5 turns off when the current flowing through the fan motor 2 becomes zero,
There is an advantage that strict OFF timing setting is not required and noise generation at the time of OFF can be suppressed.

The variable resistor 11, which is connected to the A / D conversion input terminal Q of the microcomputer 10 and serves as a rotation speed setting means, changes its resistance value to change the A / D ratio.
The voltage applied to the conversion input terminal Q changes, and it is possible to switch to a plurality of control notches according to the change. In this embodiment, as shown in FIG. 3, the A / D by the variable resistor 11 is used.
By changing the voltage applied to the conversion input terminal Q, for example, eight stages of control notches can be set. And
As shown in FIG. 3, each triac 3, 4, 5 is controlled by a control pattern corresponding to each control notch. Note that FIG.
0 during the control phase in the triac 3,4,5
Indicates OFF, 1 indicates triac 3 is ON, 2 indicates triac 4 is ON, and 3 indicates triac 5 is ON. For example, in the control notch 1, in the control phase # 1, the triac 3 operates in the control phase #
2, the triac 4 is turned on in the control phase # 3, the triac 5 is turned on in the control phase # 3, and the triacs 3, 4, 5 are turned on in the control phases # 4 to # 8.
A control pattern for FF is adopted, and for the control notch 8, a control pattern for turning on only the triac 3 in the control phases # 1 to # 8 is adopted.

The triacs 3, 4, and 5 as ON / OFF control elements in the fan motor rotation speed control circuit having the above-described configuration can be configured by elements such as transistors, and the number of them is limited to three. 2 or 4
It can be more than one. However, since the series circuit of the ON / OFF control elements has resistors 6 and 7 as current limiting elements and generates heat, it is not a good idea to increase the number too much. Further, the voltage comparator 9 is only required to be capable of detecting the phase of the power supply voltage, and the same effect can be obtained by the zero-cross detection circuit according to the conventional technique shown in FIG. 17, for example. The control cycle does not have to be limited to the period of four cycles of the commercial power supply 1, and if it is selected to be an odd multiple of a half wave of the power supply cycle, the average value of the voltage applied to the fan motor 2 will always be 0, and the coil applied by direct current will be applied. It is possible to suppress the demagnetization and deterioration of parts such as capacitors.

Embodiment 2 FIG. In the second embodiment shown in FIGS. 4 and 5, the current limiting circuit 8 in the rotation speed control circuit of the fan motor of the first embodiment described above is used as current limiting means capable of continuously controlling the amount of current. Is controlled by the control timing generation means from the phase of the power supply voltage detected by the voltage phase detection means for detecting the phase of the power supply voltage, and the fan motor 2 is turned off when the current to the fan motor 2 is cut off.
The current to be supplied is gradually reduced instead of stepwise, and the configuration other than the portion related to this configuration is the same as that shown in the first embodiment. Therefore, the same or corresponding parts as those of the first embodiment are designated by the same reference numerals as those of the first embodiment, and the detailed description thereof will be omitted.

In the fan motor rotation speed control circuit of the second embodiment shown in FIG. 4, a current limiting means 15 capable of continuously controlling the amount of current is inserted between the commercial power source 1 and the fan motor 2. Between the terminals of the commercial power source 1, a voltage comparator 9 is connected as a voltage phase detecting means for detecting the phase of the power source voltage.

Reference numeral 16 is a microcomputer as control timing generating means for generating control timing from the phase of the power supply voltage. The output side of the voltage comparator 9 is connected to its input terminal P and the variable resistor 11 as rotation speed setting means is provided. It is connected to the A / D conversion input terminal Q. The output terminal R of the microcomputer 16 is connected to the gate of the voltage-resistance conversion FET (junction type field effect transistor) 17 of the current limiting means 15, and the drive voltage of the FET 17 is output.

The current limiting means 15 includes diodes 18, 19, 20, 21 for rectifying an alternating current, a transistor 22 for controlling the current of the fan motor 2, an operational amplifier 23, a current detecting resistor 24, a voltage dividing resistor 25, and a FET 17. It is composed by. The full-wave rectified AC voltage by the diodes 18 to 21 is applied as V1 across the collector of the transistor 22 and the current detection resistor 24. This voltage V1 is also applied to the series circuit of the voltage dividing resistor 25 and the FET 17 and divided by the drain terminal of the FET 17 to obtain the voltage V1.
2 occurs.

The FET 17 exhibits a constant resistance characteristic in a region where the drain voltage is low, and when the voltage applied between the gate and the source is high, the FET 17 exhibits a characteristic similar to a resistance having a small value between the drain and the source. On the contrary, when the voltage applied between the gate and the source is low, the characteristic between the drain and the source is similar to that of a large resistance. Therefore, the FET 17 can be regarded as a resistor whose value changes according to the voltage applied between its gate and source. The operational amplifier 23 uses the voltage V3 appearing at the terminal of the current detection resistor 24 and the FET 17
It operates so that the voltage V2 divided by the drain terminal of the same becomes the same.

The voltage V2 is V1.Rfet / (R23 + R
fet), and the voltage V3 is calculated by R24 · Ic. Where Rfet is the equivalent resistance between the drain and source of the FET 17, R25 is the resistance value of the voltage dividing resistor 25,
R24 is the resistance value of the current detection resistor 24, and Ic is the collector current of the transistor 22 (collector current and emitter current are assumed to be substantially equal). Since the operational amplifier 23 operates so that the voltage V3 and the voltage V2 are the same,
V1 / Ic = R24 ・ (R25 + Rfet) / Rfet
When this is set as Rx, V1 / Ic, that is, the current limiting means 15 operates as a whole equivalent to a resistor having a resistance value of Rx, and the value becomes variable depending on the value of Rfet. Therefore, if the voltage applied between the gate and the source of the FET 17 increases, Rfet decreases and Rx decreases.
Grows. Further, when the voltage applied between the gate and the source of the FET 17 becomes low, Rfet becomes large and Rx
Becomes smaller. That is, the resistance value Rx of the entire current limiting unit 15 can be changed by the voltage applied between the gate and the source of the FET 17.

The operation of the above-described fan motor rotation speed control circuit will be described in the case where the control cycle is four cycles of the power supply voltage. First, the voltage comparator 9 detects the phase of the voltage of the commercial power supply 1. The waveform of the power supply voltage is A in Fig. 5,
The detected phase which is the output of the voltage comparator 9 is B in FIG.
Microcomputer 1 to which the output of voltage comparator 9 is input
6 outputs from the output terminal R the drive voltage indicated by the solid line in C of FIG.

The drive voltage of the microcomputer 16 is
The equivalent resistance of the current limiting means 15 inputted to the current limiting means 15 is controlled as shown by the solid line in D of FIG. Thereby, the current of the fan motor 2 is controlled as shown by the solid line in E of FIG. By adjusting the variable resistor 11, the voltage of the A / D conversion input terminal Q of the microcomputer 16 can be changed.

When the voltage at the A / D conversion input terminal Q is high, the microcomputer 16 current-limits the drive voltage indicated by the alternate long and short dash line in which the bending point of the voltage indicated by T in C of FIG. 5 changes in the direction of T2. Output to the means 15. At this time, the equivalent resistance of the current limiting means 15 has a waveform shown by the one-dot chain line in D of FIG. 5, and the current of the fan motor 2 is shown in FIG.
The waveform becomes as indicated by the alternate long and short dash line at E. That is, the effective current of the fan motor 2 increases and the rotation speed thereof increases.
When the voltage at the A / D conversion input terminal Q is low, the microcomputer 16 outputs to the current limiting means 15 the drive voltage indicated by the dotted line in which the bending point of the voltage T shown in C of FIG. 5 changes in the direction T1. To do. At this time, the current limiting means 1
The equivalent resistance of No. 5 has a waveform shown by a dotted line in FIG. 5D, and the current of the fan motor 2 has a waveform shown by a dotted line in E of FIG. That is, the effective current of the fan motor 2 is reduced and the rotation speed thereof is reduced. The position of the bending point of the voltage indicated by T in C of FIG. 5 can be continuously changed, and the rotation speed can be controlled by a fine control amount.

According to the fan motor rotation speed control circuit of the second embodiment, the torque fluctuation when the current to the fan motor 2 is cut off becomes more moderate, and the noise accompanying the steep torque fluctuation when the power is cut off is reduced. Becomes remarkable. When the energization time is an odd number of half cycles of the power supply voltage, the noise generated tends to increase, but this point can also be improved by reducing the current when the power is cut off. Since the control operation is slow, electrical noise is less likely to occur, and the number of constituent parts can be reduced, thereby reducing the cost. Although the transistor 22 is a heat-generating component, the heat radiation efficiency can be improved if it has a shape with high heat radiation efficiency.

Example 3. This Example 3 illustrated by FIG.
Is a microcomputer 1 as a control timing generating means for generating a control timing from the phase of the power supply voltage in the rotation speed control circuit of the fan motor of the first embodiment.
By setting 0, when starting to energize the fan motor 2 in the control cycle, a plurality of ON / OFF control elements are switched for each integer multiple of a half cycle of the power supply voltage at a certain phase of the power supply voltage so that the current flowing to the fan motor 2 is stepwise It is intended to increase. Therefore, since the basic structure is the same as that of the first embodiment, the same reference numerals as those of the first embodiment are used for the same or corresponding parts of the first embodiment with reference to FIG. 1, and the description thereof is omitted. .

As in the case of the first embodiment, when the current to the fan motor 2 in the control cycle is cut off, its effective value is controlled and gradually reduced so that the noise can be sufficiently reduced. Noise can be further reduced by gradually increasing the current flowing to the fan motor 2 even when the energization of the fan motor is started. However,
In reality, noise is more likely to occur when the current to the fan motor 2 is cut off. This is the fan motor 2 even if the current is cut off.
It is conceivable that a current tends to flow in the coil of (1), and this current works externally and acts on the fan motor 2 as a braking force.

Since the configuration and operation relating to the control when the current to the fan motor 2 is cut off have been described in the first embodiment, the description thereof will be omitted. Here, the control cycle is 4 cycles of the power supply voltage, and the control notch is 2 steps among 8 steps.
As will be described below, the operation of gradually increasing the current flowing to the fan motor 2 when the energization of the fan motor 2 is started will be described assuming that the control is performed in units of control phases # 1 to # 8.

The voltage comparator 9 detects the voltage phase of the commercial power supply 1. The waveform of the power supply voltage of the commercial power supply 1 is as shown by A in FIG. 6, and the voltage comparator 9 outputs a signal as shown by B in FIG. 6 as the detection phase. The microcomputer 10 to which the output of the voltage comparator 9 is input is
At the timings shown in D and E, drive pulses are generated and output to the output terminals X, Y and Z thereof. The drive pulses output to the output terminals X, Y and Z control ON / OFF of the triacs 3, 4 and 5 as indicated by F, G and H in FIG. 6, respectively. No resistors are connected to the triac 3, but resistors 6 and 7 as current limiting elements are connected in series to the triacs 4 and 5, respectively. Therefore, when the triac 4 or the triac 5 is ON, the fan motor 2 is connected. The current waveform of the fan motor 2 is limited, and the effective waveform of the current waveform of the fan motor 2 is controlled stepwise when the fan motor 2 is energized in the control cycle, as indicated by I in FIG.

By adjusting the variable resistor 11 to change the voltage applied to the A / D conversion input terminal Q, for example, 8-step control notches can be set as shown in FIG. Then, as shown in FIG. 7, the triacs 3, 4, and 5 are controlled by the control pattern corresponding to each control notch. During the control phase in FIG. 7, 0 is the triac 3, 4, 5 is off, 1 is the triac 3 is on,
2 Triac 4 is ON, 3 Triac 5 is O
Each represents N. For example, with control notch 1,
In the control phase # 1, the triac 5 is turned on, in the control phase # 2, the triac 4 is turned on, and in the control phase # 3, the triac 3 is turned on.
However, the triac 4 is turned on in the control phase # 4.
However, in the control phase # 5, the triac 5 is turned on.
However, in the control phases # 6 to # 8, the control pattern in which the triacs 3, 4, and 5 are turned off is adopted, and in the control notch 4, the triac 5 is in the control phase # 1, and the triac is in the control phase # 2. Four
However, in the control phases # 3 to # 6, the triac 3 is turned on, the triac 4 is turned on in the control phase # 7, and the triac 5 is turned on in the control phase # 8.

Therefore, in the third embodiment, the first embodiment
In addition to the functions of the above, the inrush current at power-on is reduced, which allows the use of a smaller power control element, which contributes to cost reduction, and the smooth rise of torque at power-on, which causes noise. It can be further suppressed.

Example 4. This Example 4 illustrated by FIG.
Is a microcomputer 1 as control timing generation means for generating control timing from the phase of the power supply voltage in the fan motor rotation speed control circuit of the second embodiment.
According to 6, the current flowing to the fan motor 2 is gradually increased from a certain phase of the power supply voltage when the energization of the fan motor 2 in the control cycle is started. Therefore, since the basic configuration is the same as that of the second embodiment, the same reference numerals as those of the second embodiment are used with reference to FIG. 4, and the same or corresponding parts as those of the second embodiment are denoted by the same reference numerals. .

As in the second embodiment, when the current to the fan motor 2 in the control cycle is cut off, its effective value is controlled and continuously reduced, so that the noise can be sufficiently reduced, but the fan motor 2 in the control cycle is reduced. Noise can be further reduced by gradually increasing the current flowing to the fan motor 2 even when energization to the fan motor is started.

Since the configuration and function relating to the control when the current to the fan motor 2 is cut off have been described in the second embodiment, the description thereof will be omitted. Here, the operation of increasing the current when the energization of the fan motor 2 is started will be described when the control cycle is four cycles of the power supply voltage.

The voltage comparator 9 detects the voltage phase of the commercial power supply 1. The waveform of the power supply voltage of the commercial power supply 1 is as shown by A in FIG. 8, and the voltage comparator 9 outputs a signal as shown by B in FIG. 8 as the detection phase. The microcomputer 16 which receives the output of the voltage comparator 9 outputs the drive voltage indicated by C in FIG. 8 from its output terminal R. This drive voltage is input to the current limiting means 15, whereby the current of the fan motor 2 is limited as shown by the solid line in E of FIG. By adjusting the variable resistor 11, the voltage of the A / D conversion input terminal Q of the microcomputer 16 can be changed.

When the voltage at the A / D conversion input terminal Q is high, the microcomputer 16 current-limits the drive voltage indicated by the alternate long and short dash line in which the bending point of the voltage indicated by T in C of FIG. 8 changes in the direction of T2. Output to the means 15. At this time, the equivalent resistance of the current limiting means 15 has a waveform shown by the one-dot chain line in D of FIG. 8, and the current of the fan motor 2 is shown in FIG.
The waveform becomes as indicated by the alternate long and short dash line at E. That is, the effective current of the fan motor 2 increases and the rotation speed thereof increases.
When the voltage of the A / D conversion input terminal Q is low, the microcomputer 16 outputs to the current limiting means 15 the drive voltage indicated by the dotted line in which the bending point of the voltage indicated by T in C of FIG. 8 changes in the direction of T1. To do. At this time, the current limiting means 1
The equivalent resistance of No. 5 has a waveform shown by a dotted line in D of FIG. 8, and the current of the fan motor 2 has a waveform shown by a dotted line in E of FIG. That is, the effective current of the fan motor 2 is reduced and the rotation speed thereof is reduced. The position of the bending point of the voltage indicated by T in C of FIG. 8 can be continuously changed, and the rotation speed can be controlled by a finely controlled amount.

Therefore, in the fourth embodiment, the second embodiment is used.
In addition to the functions of the above, the inrush current at power-on is reduced, which allows the use of a smaller power control element, which contributes to cost reduction, and the smooth rise of torque at power-on, which causes noise. It can be further suppressed.

Example 5. The fifth embodiment shown in FIG. 9 and FIG. 10 is a microcomputer 10 as a control timing generating means for generating a control timing from the phase of the power supply voltage in the rotation speed control circuits of the fan motors of the first and second embodiments. 16 is provided with a setting means for setting the power-on phase, and the other configuration is the same as that of the first or second embodiment. Therefore, the same or corresponding parts as those of the first and second embodiments are designated by the same reference numerals as those of the first and second embodiments, and the description thereof will be omitted.

In the fifth embodiment, the variable resistor 26 as the power-on phase setting means is connected to the A / D conversion input terminals R of the microcomputers 10 and 16. For example, as shown in FIG. 9, the variable resistor 2 is connected to another A / D conversion input terminal R in the microcomputer 10 of the rotation speed control circuit of the fan motor having the configuration shown in the first embodiment.
In the configuration in which 6 is connected, the voltage set by the variable resistor 26 is input to the A / D conversion input terminal R of the microcomputer 10, and the drive signal generated by the microcomputer 10 and indicated by C in FIG. It works to adjust the falling phase.

The basic operation is as shown in FIG. 2 in the first embodiment, but when the set voltage of the variable resistor 26 is increased as shown in FIG. 10, the microcomputer 10 is shown by the dotted line at C in FIG. Output terminal X at the timing
The drive pulse is generated and output to. As a result, the energized state of the triac 3 becomes like the dotted line in F of FIG. 10, and the current of the fan motor 2 becomes like the dotted line in I of FIG. Further, when the set voltage of the variable resistor 26 is lowered, the microcomputer 10 generates and outputs a drive pulse to the output terminal X at the timing shown by the alternate long and short dash line in C of FIG. As a result, the energization state of the triac 3 becomes like the one-dot chain line in F of FIG. 10, and the current of the fan motor 2 becomes like the one-dot chain line in I of FIG. 10, and the power-on phase can be adjusted.
In the second embodiment, the power-on phase can be adjusted with the same configuration. The power-on point at which the noise generated during control is minimized differs depending on the motor, but this can be adjusted to the power-on point at which the noise generated by the fan motor 2 is minimized, thus increasing adaptability.

Example 6. In the sixth embodiment, similarly to the fan motor rotation speed control circuit shown in the fifth embodiment, the microcomputer 10, 16 as the control timing generating means is provided with setting means for setting the power-on phase. Since the configuration and the operation are the same as those of the fifth embodiment, the description thereof will be omitted and the fifth embodiment will be described.
FIGS. 9 and 10 relating to FIG.

In the sixth embodiment, the variable resistor 26 as the power-on phase setting means connected to the A / D conversion input terminal R of the microcomputer 10 causes the power-on phase slightly before the zero cross of the commercial power source 1. It has been set. Noise is likely to be superimposed on the commercial power source 1 due to the influence of devices used in the vicinity. When such noise is superimposed, it is easily affected by noise near the zero crossing in the circuit configuration, and the detection phase which is the output of the voltage comparator 9 is B in FIG.
Fluctuates as indicated by the dotted line and the alternate long and short dash line. When the detected phase fluctuates in this way, the drive signal also fluctuates as indicated by a dotted line or a chain line in C of FIG.

During the delay phase in which the drive signal fluctuates rearward as shown by the alternate long and short dash line in FIG. 11C, the current of the fan motor 2 includes harmonics in the current waveform as shown in D of FIG. Easier to do. Further, when the drive signal is in the advance phase in which the drive signal fluctuates forward as shown by the dotted line in C of FIG. 11, the current of the fan motor 2 has a small number of harmonic components contained in the current waveform as shown in E of FIG. Occurrence will be less. By setting the power-on phase slightly before the zero cross of the commercial power supply 1, even if noise is superimposed on the power supply voltage, the drive signal is
As indicated by F, the possibility of shifting backward is reduced, and the generation of noise associated with the delay phase can be reduced. Further, since the contribution rate of noise generation due to the variation of the control circuit itself and the jitter of the voltage comparator 9 becomes small, the noise reduction is promoted as a result.

Example 7. The seventh embodiment shown in FIG. 12 is
Similar to the fan motor rotation speed control circuit shown in the fifth embodiment, the microcomputer 10 or 16 as the control timing generating means is provided with setting means for setting the power-on phase. The setting means can set the power-on phase according to the difference in the power supply frequency. The other configurations and operations are the same as those of the fifth embodiment, and therefore their explanations are omitted.

In the fan motor rotation speed control circuit of the seventh embodiment, as shown in FIG. 12, the microcomputer 10 as the control timing generating means can independently set the power-on phase corresponding to the difference in the power supply frequency. Variable resistors 27 and 28 as power-on phase setting means are switchably connected. One of the variable resistors 27 and 28 is for setting the power-on phase for 50 Hz,
The other one is for setting the power-on phase for 60 Hz, and the microcomputer 10 is connected via the common selection switch 29.
Of A / D conversion input terminals R. The selection switch 29 is switched to either the 50 Hz side or the 60 Hz side by the output of the power supply frequency detector 30 which is connected to the output side of the voltage comparator 9 and serves as a frequency discriminating means of 50/60 Hz. The other construction is the fifth embodiment.
Is the same as

The power supply frequency detector 30 has a power supply frequency of 5
It is determined whether it is 0 Hz or 60 Hz, and if it is 50 Hz, the output becomes H level, and the variable resistor 27 and the A / D conversion input terminal R of the microcomputer 10 are connected. As a result, the power-on phase can be adjusted by the variable resistor 27. If it is 60 Hz, the output of the power supply frequency detector 30 becomes L level, and the variable resistor 28 and the A / D conversion input terminal R of the microcomputer 10 are connected. As a result, the power-on phase can be adjusted by the variable resistor 28. That is, the characteristics of the fan motor 2 change according to the power supply frequency, but the optimum power-on phase can be set at each power supply frequency, and noise can be reduced in any area where the power supply frequency is different. .

Both the power supply frequency detector 30 and the selection switch 29 can be realized as a built-in function of the microcomputers 10 and 16. Further, the variable resistors 27 and 28 may be composed of several fixed resistors, because the power-on phase may be set to a certain constant value for the fan motor 2.

Example 8. The eighth embodiment has the same configuration as the rotation speed control circuit of the fan motor of the first and second embodiments described above, and the variable resistor 11 is varied in the microcomputers 10 and 16 as the control timing generating means. At this time, the control pattern is set so that the control cycle changes. Other configurations are the same as those in the first and second embodiments.
Since these are the same as those in FIG.

In the eighth embodiment, when the variable resistor 11 is varied as shown in FIG. 13, the control pattern is set so that the control cycle for repeating ON / OFF of energization of the fan motor 2 changes. In accordance with this control pattern, the triacs 3, 4, 5 are sequentially turned on / off, or the current limiting means 15 is operated. In FIG. 13, for example, the control notch 1 has a control cycle of 4 cycles, and the control notch 2 has a control cycle of 3.5 cycles.
By making it possible to change the control cycle, the control cycle can be set as short as possible, and the change in the rotation speed of the fan motor 2 can be suppressed small.
In addition, the selection range of the control pattern is expanded, so that it is possible to select a control pattern with less noise generation, and various control amounts can be selected.

Example 9. The ninth embodiment basically has the same configuration as the rotation speed control circuit of the fan motors of the first and second embodiments described above, and the fan motor 2 is a single-phase capacitor motor 2a, and its main coil 31 side. It is intended to control only. The configuration other than this is the same as that of the first and second embodiments, and therefore the description will be given here based on FIG. 14 according to the first embodiment. In addition, Example 1
The same reference numerals are used for the common parts and the description thereof will be omitted.

As shown in FIG. 14, ON / O is provided between the main coil 31 of the single-phase capacitor motor 2a and the commercial power supply 1.
A current limiting circuit 8 in which a plurality of series circuits including triacs 3, 4, and 5 as FF control elements and resistors 6 and 7 as current limiting elements are connected in parallel is inserted. The auxiliary coil 32 is directly connected to the commercial power supply 1 via the phase advancing capacitor 33. The other configuration is the same as that of the first embodiment.

The operation of the rotation speed control circuit of the fan motor will be described with reference to FIG. 15 when the control cycle is 4 cycles of the power supply voltage and the control notch is 4. 15A
Since the current of the auxiliary coil 32 is connected to the commercial power source 1 via the phase advancing capacitor 33 with respect to the waveform of the power source voltage shown by, it is always constant as shown in B of FIG. The current of the main coil 31 is controlled by the current limiting circuit 8 and becomes as shown in C of FIG. 15 as described in the first embodiment. The total current of the condenser motor 2a as a whole is calculated by the auxiliary coil 3
2 and the current of the main coil 31 are summed up, as shown in D of FIG.

That is, since only the coil load is controlled, the change in current when the power is turned on becomes gentle, and even if the power-on phase is slightly shifted, the noise is less likely to be involved and the noise can be suppressed. Further, since only the main coil 31 is controlled, the current to be controlled is small, and a small element can be used, so that the cost is also reduced. Since the voltage to the auxiliary coil 32 does not decrease, the decrease in the rotation speed of the capacitor motor 2a due to the voltage drop by the current limiting circuit 8 becomes small. Furthermore, since the change in the total input current due to the energization control is small, it has little effect on other devices that use the same power supply system.

In the ninth embodiment, the total current of the capacitor motor 2a is as shown in D of FIG. 15 as described above, and the change of the current is small, so that the following advantages can be obtained. . That is, as shown in FIG. 16, a switch 3 with a pilot lamp is provided in an actual operating circuit such as a ventilation fan.
4 is often connected. This type of switch 34 turns on and off the current flowing through the load 35,
The current flowing through the transformer is sent to a light emitting diode 37, which is a pilot lamp, through a transformer 36 to illuminate it. When the fan motor 2 having the control circuit shown in the first or second embodiment is connected as the load 35, the current of the fan motor 2 is switched on and off, so that the light emitting diode 37 blinks frequently. The blinking cycle depends on the power supply frequency and the control cycle. For example, the power supply frequency is 50 Hz.
In the case where the control cycle is 5 cycles of the power supply cycle, the blinking cycle is 10 Hz, which is a cycle with high sensitivity to the human eye, which causes discomfort due to eyesore. When this embodiment is connected as the load 35 of the driving circuit as described above, the change in current is small, so the light emitting diode 37 is used.
The blinking of is reduced to avoid annoying conditions.

[0073]

As is apparent from the above description of the embodiments, according to the first aspect of the invention, the fan motor is rotated by turning on and off the current to the fan motor at a control cycle synchronized with the phase of the power supply voltage. When controlling the speed, when switching off the current to the fan motor in the control cycle, the series circuit of multiple ON / OFF control elements and current limiting elements is switched at every integer multiple of half cycle of the power supply voltage, and the current of the series circuit is switched. The current flowing to the fan motor is gradually reduced by the limiting element, the torque fluctuation when the current to the fan motor is cut off is moderated, and the noise can be reduced with a simple structure with no cost.

According to the second aspect of the present invention, when the rotation speed of the fan motor is controlled by turning on and off the current to the fan motor in the control cycle synchronized with the phase of the power supply voltage, the fan motor in the control cycle is controlled. When the current is cut off, the current flowing to the fan motor is gradually reduced by the current limiter that can continuously control the amount of current, the torque fluctuation when the current to the fan motor is cut off becomes gentle, and the configuration is simple with no cost. Noise can be reduced.

According to the invention of claim 3, in addition to the effect according to the invention of claim 1, when energizing the fan motor in the control cycle is started, a plurality of power supply voltages are provided at a certain phase for every integer multiple of a half cycle of the power supply voltage. ON / OFF control element is switched, the current flowing to the fan motor increases stepwise by the current limiting element of the series circuit, and the torque fluctuation becomes gentle even when the current to the fan motor is cut off, further reducing noise. can do.

According to the invention of claim 4, in addition to the effect according to claim 2, when the energization of the fan motor in the control cycle is started, the current flowing to the fan motor is gradually increased by the current limiting means from a certain phase of the power supply voltage, Even when the current to the fan motor is cut off, the torque fluctuation becomes gentle, so
Noise can be further reduced.

According to the invention of claim 5, in addition to the effect according to claim 1 or claim 2, the power-on phase setting means further reduces the noise generated during control according to the fan motor. Can be adjusted to.

According to the invention of claim 6, in addition to the effect according to claim 1 or 2, the power-on phase setting means can set the power-on phase slightly before the zero crossing of the power source. Even if noise is superimposed on the power supply voltage due to the influence of the equipment used in the above, the output signal of the control timing generation means is less likely to shift backward from the zero cross of the power supply, and the noise due to the influence of noise is reduced.

According to the invention of claim 7, in addition to the effect according to claim 1 or claim 2, by switching the power-on phase setting means according to the difference in the power-source frequency, the power-on phase is set to the frequency. It can be optimally applied to, and can be applied to areas with different power supply frequencies.

According to the invention of claim 8, in addition to the effect according to claim 1 or claim 2, the control cycle can be changed in accordance with the multi-step control notch set by the control notch setting means. Therefore, it is possible to select a control notch that generates less noise, and to shorten the control period to suppress changes in the rotation speed of the fan motor and suppress noise generation.

According to the invention of claim 9, in addition to the effect according to claim 1 or claim 2, the current of the main coil of the capacitor motor is controlled, but the current of the auxiliary coil is not controlled and is constant. , The total current becomes the sum of them, and the current to be controlled can be made small, and the current change at power-on becomes gentle because only the coil load is controlled, and the power-on phase shifts slightly. However, it does not lead to the generation of noise.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a rotation speed control circuit of a fan motor according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation timing of the first embodiment.

FIG. 3 is an explanatory view showing a control operation of the first embodiment as a table.

FIG. 4 is a circuit configuration diagram of a rotation speed control circuit for a fan motor according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing operation timing of the second embodiment.

FIG. 6 is an explanatory diagram showing operation timing of the third embodiment.

FIG. 7 is an explanatory view showing a control operation of the third embodiment as a table.

FIG. 8 is an explanatory diagram showing operation timing of the fourth embodiment.

FIG. 9 is a circuit configuration diagram of a rotation speed control circuit of a fan motor according to a fifth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing operation timing of the fifth embodiment.

FIG. 11 is an explanatory diagram showing operation timing of the sixth embodiment.

FIG. 12 is a circuit configuration diagram of a rotation speed control circuit for a fan motor according to a seventh embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a table of control operations of a rotation speed control circuit for a fan motor according to an eighth embodiment of the present invention.

FIG. 14 is a circuit configuration diagram of a fan motor rotation speed control circuit according to a ninth embodiment of the present invention.

FIG. 15 is an explanatory diagram showing operation timing of the ninth embodiment.

FIG. 16 is an operation circuit diagram illustrating the function of the ninth embodiment.

FIG. 17 is a circuit configuration diagram of a conventional fan motor rotation speed control circuit.

18 is an explanatory diagram showing operation timings of the circuit shown in FIG.

FIG. 19 is a circuit configuration diagram of a conventional motor rotation speed control circuit.

20 is an explanatory diagram showing an operation timing of the circuit shown in FIG.

[Explanation of symbols]

 1 Commercial Power Supply 2 Fan Motor 3 Triac 4 Triac 5 Triac 6 Resistance 7 Resistance 9 Voltage Comparator 10 Microcomputer 11 Variable Resistor 15 Current Limiting Means 16 Microcomputer 26 Variable Resistor 28 Variable Resistor 28 Variable Resistor 29 Selection Switch 30 Power frequency detector 31 Main coil 32 Auxiliary coil 2a Capacitor motor

Claims (9)

[Claims] 1. A method for controlling a rotation speed of a fan motor by turning on and off a current to the fan motor at a control cycle synchronized with a phase of a power supply voltage. Of the ON / OFF control element and the current limiting element are connected in parallel and inserted, and the plurality of ON / OFF control elements of these series circuits are detected by the voltage phase detection means for detecting the phase of the power supply voltage. By the control timing generating means that creates the control timing from the phase of the power supply voltage, when switching off the current to the fan motor in the control cycle, it is switched every integer multiple of half cycle of the power supply voltage to gradually reduce the current flowing to the fan motor. A rotation speed control circuit for a fan motor, characterized in that 2. A method for turning on / off a current to a fan motor at a control cycle synchronized with a phase of a power supply voltage to control a rotation speed of the fan motor, wherein a current is supplied between the AC power supply and the fan motor. A current limiting means capable of continuously controlling the amount is inserted, and this current limiting means is controlled by a control timing generating means for generating a control timing from the phase of the power supply voltage detected by the voltage phase detection means for detecting the phase of the power supply voltage. Thus, the rotation speed control circuit of the fan motor is configured to gradually reduce the current flowing to the fan motor when the current to the fan motor is cut off in the control cycle. 3. The rotation speed control circuit for the fan motor according to claim 1, wherein the control timing generation means comprises:
When starting to energize the fan motor, multiple ON / OFs are performed for each integer multiple of a half cycle of the power supply voltage at a certain phase of the power supply voltage.
A rotation speed control circuit for a fan motor, characterized in that the F control element is switched to increase the current flowing to the fan motor stepwise. 4. The rotation speed control circuit for a fan motor according to claim 2, wherein the control timing generation means comprises:
A rotation speed control circuit for a fan motor, wherein a current limiting means is controlled from a certain phase of a power supply voltage to gradually increase a current flowing to the fan motor when energization of the fan motor is started. 5. The rotation speed control circuit for a fan motor according to claim 1, further comprising a power-on phase setting means capable of arbitrarily setting a power-on phase. Fan motor rotation speed control circuit. 6. The rotation speed control circuit for a fan motor according to claim 1, further comprising a power-on phase setting means capable of setting a power-on phase slightly before the zero cross of the AC power supply. A rotation speed control circuit for a fan motor, which is provided. 7. The fan motor rotation speed control circuit according to claim 1, wherein the power-on phase of the AC power source can be set independently of the power-on phase of the AC power source. A rotation speed control circuit for a fan motor, wherein the setting means is switchably provided. 8. The rotation speed control circuit for a fan motor according to claim 1, wherein the control timing generating means is configured so that multi-step control notches can be set by the control notch setting means. The fan motor rotation speed control circuit is characterized in that the control cycle is made variable in accordance with the control notch. 9. The rotation speed control circuit for a fan motor according to claim 1, wherein the fan motor is a single-phase capacitor motor, and a plurality of capacitors are provided on the main coil side of the capacitor motor. A rotation speed control circuit for a fan motor, wherein a series circuit including an ON / OFF control element and a current limiting element is connected in parallel or inserted, or a current limiting means capable of continuously controlling the amount of current is inserted.