JPH0779596A - Ventilation fan controller - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a ventilation fan control device capable of controlling a large load capable of causing a relatively large current to flow through a transistor of a flywheel circuit, and having few failures against lightning surges. [Configuration] AC power supply 1 and ventilation fan motor 2 so that both positive and negative switching is performed at a frequency higher than the power supply frequency.
And a switching circuit 3 connected in series between and, and a pair of flywheel transistors 1 connected in parallel to the ventilation fan motor 2 and performing both positive and negative flywheeling.
1 and 16 and a voltage comparator 36 that operates the switching circuit 3, and the bases of the transistors 11 and 16 alternate according to the polarity of the AC power supply 1 regardless of the switching operation of the switching circuit 3. A continuous current is supplied from the AC power supply 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilation fan control device for a ventilation fan that operates by inputting an AC voltage.

[0002]

2. Description of the Related Art Many conventional ventilation fan control devices have a structure as shown in, for example, Japanese Utility Model Publication No. 56-49277, and a pulse drive circuit is formed as shown in FIG. In FIG. 7, both terminals V of the AC power source 70,
Between W, AC motor 71, diode 72 (or diode 74), collector / emitter of transistor 76,
A series switching circuit of the diode 75 (or the diode 73) is connected. A pulse input for driving is applied between the base and emitter of the transistor 76.
The PNP is connected in parallel to both terminals Y and X of the AC motor 71.
The emitter and collector of the transistor 77 and NPN transistor 78 are connected to each other, and the PNP transistor 77 and N
The base of the PN transistor 78 is connected to the terminal V of the AC power supply 70 via the base current supply resistors 79 and 80 and the protection diodes 81 and 82 to form a flywheel circuit. Reference numerals 83 and 84 are protection diodes connected in series to the PNP transistor 77 and the NPN transistor 78.

In the control circuit having the above structure, when a pulse voltage is supplied to the base of the transistor 76, the positive half cycle of the supply signal from the terminal W on the + side of the AC power supply 70 causes the AC motor 71 and the diode 72 to operate. , Collector of transistor 76, emitter, diode 75, terminal V
And the switching is performed. Further, the negative half cycle of the supply signal from the-side terminal V flows through the path of the diode 74, the collector and emitter of the transistor 76, the diode 73, the AC motor 71, and the terminal W for switching.

The collector voltage of the transistor 76 has a waveform WF1 shown in FIG. 8A, and a voltage such as a waveform WF2 shown in FIG. 8B is applied to the AC motor 71.
The AC motor 71 has an inductance component, and when the supply voltage becomes zero, the counter electromotive voltage WB1 as shown by B in FIG. 8 is generated, but both terminals X and Y of the AC motor 71 are mutually connected. PNP transistor 7 with different polarities
7 and the NPN transistor 78 are connected in parallel, only the waveform WF2 shown in B of FIG. 8 is obtained. That is,
During the positive half cycle of the power supply with the transistor 76 in the conductive state (when the terminal W is + and the terminal V is −), the AC motor 7
When the positive voltage applied between both terminals Y and X of No. 1 causes the transistor 76 to become non-conductive, the counter electromotive voltage due to the inductance component of the AC motor 71 causes the AC motor 71 to move.
A negative voltage is generated between the two terminals Y and X. At this time, P
Since the base voltage of the NP transistor 77 is negative with respect to the terminal Y of the AC motor 71, the counter electromotive current is PNP.
By passing the current to the transistor 77, only the waveform WF2 is obtained.

In the negative half cycle, a counter electromotive current flows through the NPN transistor 78, and the counter electromotive voltage of the AC motor 71 generated when the transistor 76 is in the non-conducting state is prevented by the PNP transistor 77 and the NPN transistor 78. Will be. The current flowing through the AC motor 71 is
It is integrated by the inductance of the AC motor 71 and is C in FIG.
It becomes the sine wave current shown in.

Instead of the pulse drive circuit as described above, as shown in FIG. 9, there is also one that performs speed control by switching the taps of the ventilation fan motor 85. That is, the ventilation fan 86 has terminals W and V with the AC power supply 87 and a control signal input terminal Z for inputting a control signal from the outside, and the control signal from the control switch 88 connected to the control signal input terminal Z causes a strong signal.
Weak two-step control is possible. When no external control is performed, the connection is changed and the strong / weak initial setting is performed.

[0007]

In the conventional ventilation fan control device as described above, the AC motor 7 which is an inductive load.
1 and the back electromotive force generated when controlling the ventilation fan motor 85 are suppressed by the flywheel circuit.
Since the base currents of the transistor 77 and the NPN transistor 78 change greatly with the switching operation of the transistor 76 of the switching circuit, there is no problem in the ventilation fan motor 85 with relatively low power consumption, but in the case of the ventilation fan motor 85 with high power consumption. The ON operation of the flywheel circuit is delayed, the back electromotive voltage of the ventilation fan motor 85 becomes large, and the PNP transistor 77 and NPN
This includes problems to be solved such as a rise in the temperature of the transistor 78 and a failure.

Further, when a lightning surge or the like propagates to the power source due to inductive lightning, the PNP transistor 77 and the NPN transistor 78 of the flywheel circuit and the switching transistor 76 are likely to fail. For example, the voltage applied to the terminal V has a positive half cycle, and the transistor 7
When a lightning surge is applied to the base of the NPN transistor 78 when the 6 is on, the NPN transistor 78
Will turn on and short the power supply. PN
Although a power supply short circuit can be prevented by inserting a capacitor between the base and emitter of the P transistor 77 and the NPN transistor 78, a pulsed voltage is applied to the PNP transistor 77 and the NPN transistor 78, so that the ON timing Delay, the surge voltage of the ventilation fan motor 85 cannot be absorbed, and the PNP transistor 7
7 and the NPN transistor 78 also increase in loss, causing a failure.

Further, in general, as for the power source for lighting fixtures such as buildings, AC200V has become mainstream in recent years, in contrast to the ventilation fan which is generally operated by AC power source AC100V.
When the ventilation fan 86 is attached to a ceiling or a wall in which a power supply line and a 200V power supply line are mixed, it sometimes happens that the ventilation fan 86 is connected to the 200V power supply line. Although such misconnection can often be detected by the occurrence of abnormal sound when checking the operation,
If it is operated for several minutes or more without being discovered, heat generation, failure, smoke generation, etc. of the ventilation fan motor 85 will be caused.

Further, the ventilation fan 86 can be controlled by an external control switch 88, or the ventilation fan 86 can be controlled without the external control switch 88, as shown in FIG. It requires a connection change and cannot be handled by general users.

The present invention has been made in order to solve the above-mentioned conventional problems, and the first purpose thereof is to enable control of a large load capable of allowing a relatively large current to flow through a transistor of a flywheel circuit. , Is to provide a ventilation fan control device with few failures against lightning surges,
The second is to provide a ventilation fan control device that can avoid erroneous connection, and the third is to provide an easy-to-use ventilation fan control device that automatically switches between external control means and internal control means. It is to be.

[0012]

According to a first aspect of the present invention, there is provided a ventilation fan control device, wherein a switching circuit connected in series between an AC power source and a ventilation fan motor so as to perform both positive and negative switching, and a switching circuit connected in parallel to the ventilation fan motor. It is equipped with a pair of flywheel transistors that perform both positive and negative flywheeling, and a control circuit that operates the switching circuit. The base of each transistor for the flywheel is independent of the switching operation of the switching circuit. According to the polarity of the AC power supply, a continuous current is alternately supplied from the AC power supply.

A ventilation fan control device according to a second aspect of the present invention includes speed control means for controlling the speed of a ventilation fan motor operated by an AC power source in multiple stages, and voltage detection means for detecting that the voltage of the AC power source exceeds a certain value. A stop means for stopping the supply of the AC power to the ventilation fan motor by the detection signal of the voltage detection means is provided.

According to another aspect of the present invention, there is provided a ventilation fan control device including speed control means for controlling a speed of a ventilation fan motor operated by an AC power source in multiple stages, and a speed control means provided from outside the speed control signal input terminal. The control circuit includes a detachable external control means for speed control, and an internal control means incorporated in the ventilation fan for speed control by the speed control circuit.By connecting the external control means, the external control means and the speed control means are connected. With the connection, the internal control means and the speed control means are separated, and the external control means is separated,
The internal control means and the speed control means are connected.

[0015]

According to the first aspect of the present invention, a continuous and stable current flows through the bases of the respective transistors of the flywheel circuit alternately according to the polarity of the AC power source regardless of the switching operation of the switching circuit, and the bases of the respective transistors are controlled. Can be driven sufficiently.

In the second aspect of the invention, when the voltage of the AC power source exceeds a certain value, the ventilation fan motor is stopped by the detection signal of the voltage detecting means.

According to the third aspect of the present invention, when the external control means is connected and the external control is performed, the external control means and the speed control means are connected to each other, and the internal control means and the speed control means are electrically disconnected from each other to thereby control the external control means. When the external control means is disconnected, the internal control means and the speed control means are electrically connected and controlled by the internal control means.

[0018]

【Example】

Example 1. 1, which is a circuit configuration diagram of a ventilation fan control device according to an embodiment of the present invention, a switching circuit for performing switching in both positive and negative directions with a ventilation fan motor 2 which is an inductive load in series with an AC power supply 1 which is a commercial power supply of AC100V. 3 is connected. The switching circuit 3 is composed of diodes 4, 5, 6, 7 connected in a bridge and a MOSFET 8 as a switching element. A pair of flywheel circuits 9 and 10 are provided between both terminals X and Y of the ventilation fan motor 2.

One flywheel circuit 9 includes a transistor 11, a biasing diode 12 inserted between the collector and the emitter of the transistor 11, and protective diodes 13 and 14 connected in series to the collector and the emitter, respectively. And a resistor 15 for supplying a base current, which is connected between the base of the transistor 11 and the AC power supply 1.
It is composed of and. The other flywheel circuit 1
0 is a transistor 16 and a bias diode 1 inserted between the collector and the emitter of the transistor 16.
7, a protection diode 18, 19 and a transistor 16 connected in series to the collector and the emitter, respectively.
And a resistor 20 for supplying a base current, which is connected between the base and the AC power supply 1. Rectifier diodes 21 and 22 are connected in series to the resistors 15 and 20 in the flywheel circuits 9 and 10, and capacitors 23 and 24 are connected between the base and emitter of the transistors 11 and 16.

Of the power source lines connected to the power source input terminals W and V for the AC power source 1, the power source voltage detector 25 is connected to the power source line on the side of the power source input terminal W to which the switching circuit 3 is not connected. Has been done. Power supply voltage detector 25
Is composed of a rectifying diode 26, voltage dividing resistors 27 and 28, a smoothing capacitor 29, a voltage comparator 30, resistors 31 and 32, and a protection diode 33. The voltage of the reference voltage source 34 is input to the voltage comparator 30. It The output of the voltage comparator 30 is connected to the switching input of the control voltage switching means 35. The control voltage switching means 35 is connected to a control circuit that outputs a switching pulse that operates the MOSFET 8. The control circuit comprises a voltage comparator 36 and a sawtooth voltage generator 37. In the voltage comparator 36, the voltage at the terminal U on the control voltage switching means 35 side and the sawtooth voltage generator 37.
Is compared with the output voltage of the MOSFET, and its output is supplied to the gate of the MOSFET 8 as a pulse signal. This makes MO
The SFET8 performs a switching operation.

The ventilation fan is provided with a control signal input terminal Z, and a detachable variable resistor 3 as an external control means.
It is connected to the power input terminal W via 8. A voltage generator is connected between the power input terminals W and V. This voltage generating means includes resistors 39 and 40 for voltage division and a diode 4
1 and 42, it generates a voltage approximately in the middle of the power input terminals W and V. The difference signal between the control signal input terminal Z and this voltage generating means is rectified by the bridge rectifying means composed of the diodes 43 to 46.

The output of the bridge rectifying means is converted into a voltage by the resistor 47. The voltage generated across the resistor 47 is
A resistor 48, a transistor 49, and a resistor 50 connected in series.
The voltage is shifted by the shift means configured by.
A diode 51 connected to the collector of the transistor 49 is for protection of preventing a reverse voltage from being applied to the transistor 49, and an AC power supply 1 flowing from the transistor 49 by a capacitor 52 provided in parallel with the resistor 50.
A direct current external control signal is generated from the control current for the half cycle. This external control signal is input from the external control signal output terminal T to the signal comparison section 53 and one terminal 54a of the control signal switching means 54. The signal comparison unit 53 includes resistors 55 and 56 for voltage division and a voltage comparator 57, and the output of the voltage comparator 57 is connected to the switching input of the control signal switching unit 54 connected to the control voltage switching unit 35. ing. A voltage obtained by dividing the voltage of the reference voltage source 34 by the resistors 55 and 56 is input to the inverting input terminal of the voltage comparator 57. An internal control signal output terminal S of a variable resistor 58 as internal control means is connected to the other terminal 54b of the control signal switching means 54.

In the ventilation fan control device having the above structure, when the variable resistor 38 as the external control means is connected and is connected to the proper AC power supply 1, the AC power supply 1 connects the power supply input terminals W and V. Is input with a signal having a waveform as shown by a in FIG. The voltage comparator 36 outputs the output of the sawtooth voltage generator 37 indicated by V37 in FIG.
The voltage of the terminal U shown by is input, the waveform shown by c of FIG. 2 is output, and it is applied to the gate of the MOSFET 8 as a switching pulse. The MOSFET 8 turns on when the gate voltage has a high potential, and turns off when the gate voltage has a low potential. This MOSF
Since the ET8 and the diode bridge composed of the diodes 4, 5, 6, 7 operate as a bidirectional current switch,
Both terminals X and Y of the ventilating fan motor 2 are W at d in FIG.
Voltages shown by F1 and WF2 are applied. The voltage at the terminal U of the voltage comparator 36 is changed from VU to VU in FIG.
When it changes to H, the gate of the MOSFET 8 has
The voltage shown in is applied, the electric power applied to the ventilation fan motor 2 is increased, and the ventilation fan motor 2 rotates at high speed.

When the MOSFET 8 is turned off, the MOSFET is connected to both terminals X and Y of the ventilation fan motor 2 which is an inductive load.
8 in the opposite polarity to that when 8 is on, WB in FIG.
1 and WB2 generate back electromotive force. In a half cycle in which the power input terminal V side is positive and the power input terminal W side is negative, if the MOSFET 8 is in the ON state, the diode 17 is passed from the power input terminal V to the rectifying diode 22, the resistor 20, the base of the transistor 16 and the emitter. A current flows in a path from the power supply terminal W to the power input terminal W. Also, MO
When the SFET 8 is turned off, a current flows from the power input terminal V to the power input terminal W through the rectifying diode 22, the resistor 20, the base of the transistor 16 to the emitter, the protection diode 19 to the ventilation fan motor 2.

At this time, since a reverse voltage is applied to the rectifying diode 21, no current flows through the base of the transistor 11 and the transistor 11 is turned off. Therefore, during this period, a sufficient forward bias current always flows through the base of the transistor 16. MO
While the SFET 8 is on, the voltage of the terminal X is positive with respect to the terminal Y of the ventilation fan motor 2, so that a reverse voltage is applied to the protective diode 19 and the protective diode 18, and the collector of the transistor 16 is applied. Does not flow current. When the MOSFET 8 is turned off and a back electromotive voltage is generated by the ventilation fan motor 2, the voltage of the terminal X becomes negative with respect to the terminal Y, and therefore the protection diode 18, the collector / emitter of the transistor 16 and the protection diode 1 start from the terminal Y.
A current flows in a path from the terminal 9 to the terminal X, and the counter electromotive voltage generated in the ventilation fan motor 2 can be suppressed.

Next, a half cycle in which the power input terminal W side is positive and the power input terminal V side is negative will be described.
While T8 is on, a current flows from the power supply input terminal W to the diode 17, from the emitter of the transistor 11 to the base to the power supply input terminal V through the resistor 15, the rectifying diode 21. In addition, while the MOSFET 8 is off, the path from the power supply input terminal W to the power supply input terminal V through the ventilation fan motor 2, the protection diode 14, the emitter of the transistor 11 to the base, the resistor 15, the rectifying diode 21. An electric current flows.

At this time, since a reverse voltage is applied to the rectifying diode 22, no current flows through the base of the transistor 16 and the transistor 16 is turned off. Therefore, during this period, a sufficient forward bias current always flows through the base of the transistor 11. MO
While the SFET 8 is on, the voltage of the terminal X is negative with respect to the terminal Y of the ventilation fan motor 2, so that a reverse voltage is applied to the protective diode 14 and the protective diode 13, and the collector of the transistor 11 is applied. Does not flow current. When the MOSFET 8 is turned off and a counter electromotive voltage is generated by the ventilation fan motor 2, the voltage of the terminal X becomes positive with respect to the terminal Y, so that the terminal 14 has a protective diode 14, the emitter of the transistor 11 has a collector, and the protective diode 13 has a positive polarity. An electric current flows through the path through to the terminal Y to suppress the counter electromotive voltage generated in the ventilation fan motor 2.

As mentioned above, the flywheel circuits 9, 1
The base voltage of the transistors 11 and 16 of 0 is the AC power supply 1
The polarity of the voltage changes every half cycle of
Since it has nothing to do with the switching cycle of T8, the capacitors 23 and 24 can have sufficiently large capacitances, so that noise such as surge is less likely to be applied to the bases of the transistors 11 and 16, and the circuit is strong against lightning surge. At the same time, the back electromotive voltage of the ventilation fan motor 2 can be suppressed.

Next, the function of the power supply voltage detector 25 will be described. The voltage of the AC power supply 1 is rectified by the rectifier diode 26, divided by the resistors 27 and 28, smoothed by the smoothing capacitor 29, and input to the inverting input terminal of the voltage comparator 30. That is, a DC voltage proportional to the voltage of the AC power supply 1 is input to the inverting input terminal of the voltage comparator 30.
The voltage of the reference voltage source 34 is input to the non-inverting input terminal of the voltage comparator 30 via the resistor 31. The resistor 32 is connected between the output of the voltage comparator 30 and the non-inverting input terminal, and gives the voltage comparator 30 a hysteresis characteristic as shown in FIG. That is, when the voltage of the AC power supply 1 becomes equal to or higher than the voltage V1, the output of the voltage comparator 30 becomes VL, and when the voltage of the AC power supply 1 becomes lower than the voltage V2, the output of the voltage comparator 30 becomes VH.

When the output of the voltage comparator 30 is VH, that is,
When the voltage of the AC power supply 1 is lower than V2, the control voltage switching means 35 is selected on the terminal 35a side, and the control signal switching means 5 is selected.
The signal selected in 4 is input to the voltage comparator 36, which controls the ventilation fan motor 2. When the output of the voltage comparator 30 is VL, that is, when the voltage of the AC power supply 1 is V1 or more, the control voltage switching means 35 is selected on the terminal 35b side,
A 0V signal is input to the voltage comparator 36 regardless of the control signal switching means 54, and the non-inverting input of the voltage comparator 36 is always lower than the inverting input as shown in FIG. At the level, the MOSFET 8 is turned off, and no power is supplied to the ventilation fan motor 2. Therefore,
AC100V AC power supply 1 is originally installed at a place where AC100V and AC200V AC power supplies 1 are mixed.
When the place connected to is mistakenly connected to the AC 200V AC power supply, it can be seen that the ventilation fan does not operate and the connection is incorrect. In addition, since the operation is stopped and there is no load on the circuit, troubles due to incorrect connection can be avoided.

Next, the operation control by the external control means and the internal control means will be described. In a half cycle in which the voltage of the power input terminal V is higher than that of the power input terminal W, the diode 4
Since a reverse voltage is applied to 1, 42, the diode 43
No current flows through the diode bridge constituted by ˜46, and no current flows through the resistor 47. Therefore, no voltage is generated across the resistor 47 and the transistor 49 is turned off because no voltage is applied between the base and the emitter, and no voltage is generated across the resistor 50.

In the half cycle when the voltage of the power input terminal V is lower than that of the power input terminal W, a forward voltage is applied to the diodes 41 and 42, so that the diode 4 from the power input terminal W is applied.
1, a resistor 39, a diode 45, a resistor 47, a diode 44, a control signal input terminal Z, and a variable resistor 38, and a current flows in a path to the power supply input terminal V. As a result, a voltage is generated across the resistor 47, a current substantially proportional to this voltage flows through the collector of the transistor 49, a voltage is generated across the resistor 50, and the voltage is output to the external control signal output terminal T.

As shown in FIG. 4, when the resistance value of the variable resistor 38 is increased, the current flowing through the resistor 47 is decreased, the voltage between its terminals is also decreased, and the voltage generated at the external control signal output terminal T is also decreased. When the resistance value of the variable resistor 38 is reduced, the current flowing through the resistor 47 increases, the voltage between its terminals also increases, and the voltage generated at the external control signal output terminal T also increases. In FIG. 4, the voltage of the external control signal output terminal T when the resistance value of the variable resistor 38 is R38L, R38H, R38U is VTL, VTH, VTU, respectively.
I am trying.

The voltage of the external control signal output terminal T is input to the voltage comparator 57, and the voltage of the reference voltage source 34 is changed to the resistance 55,
It is compared with the voltage VTU divided by 56. When the voltage of the external control signal output terminal T is higher than the voltage VTU (when the resistance value of the variable resistor 38 is smaller than R38U),
The output of the voltage comparator 57 becomes high level, the terminal 54a side of the control signal switching means 54 is selected, and the voltage of the external control signal output terminal T is input to the voltage comparator 36 via the control voltage switching means 35. When the voltage of the external control signal output terminal T is lower than the voltage VTU (the resistance value of the variable resistor 38 is R
(When larger than 38 U), the output of the voltage comparator 57 becomes low level, the terminal 54b side of the control signal switching means 54 is selected, and the output by the variable resistor 58 as the internal control means is changed to the voltage via the control voltage switching means 35. Comparator 36
Entered in.

When the variable resistor 38 is connected between the power source input terminal V and the control signal input terminal Z, if the variable range of the variable resistor 38 is between R38L and R38H, then R3
Since 8L <R38H <R38U, the control signal switching means 54 selects the external control signal from the external control signal output terminal T. Therefore, the variable resistor 3 of the external control means
When 8 is connected, the electric power to the ventilation fan motor 2 is controlled only by the variable resistor 38. Variable resistor 38
Is disconnected, the resistance value between the power supply input terminal V and the control signal input terminal Z approaches infinity, the output of the voltage comparator 57 becomes low level, the terminal 54b side of the control signal switching means 54 is selected, and it serves as an internal control means. The variable resistor 58 controls the electric power to the ventilation fan motor 2.

Example 2. FIG. 5 is a circuit configuration diagram of a ventilation fan control device showing another embodiment of the present invention. This embodiment is basically the same as the first embodiment shown in FIG. 1, and the switching between the external control means and the internal control means, the control relating to the voltage of the AC power supply 1, and the generation of the switching pulse to the MOSFET 8 are all performed by a single operation. It is characterized by being configured to be performed by the microcomputer 59. Therefore,
The same parts as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, but the description thereof will be omitted. As can be seen from FIG. 5, the voltage comparator 30 and the resistors 31 and 32 of the power supply voltage detection unit 25 according to the first embodiment are the microcomputer 59.
It is omitted from the configuration by the function of.

In the flow chart of the microcomputer 59 shown in FIG. 6, when the voltage of the AC power supply 1 is turned on, the control sequence starts. The output of the switching pulse is stopped in step 1, and it is determined in step 2 whether or not a fixed time has elapsed. The reason for waiting for a certain period of time is that the circuit for detecting the voltage of the AC power supply 1 needs time to stabilize. After a certain period of time, the process proceeds to step 3. In step 3, it is determined whether the voltage of the AC power source 1 is V1 or higher in FIG. If V1 or more, the process returns to step 1 and steps 1 and 2 are repeated to keep the switching pulse output stopped. If it is lower than V1, go to step 4. In step 4, the output of the switching pulse is constantly turned on in step 5 until another fixed time has not passed, and the ventilation fan motor 2 is set to the strong operation state.
At this time, in step 3, the voltage of the AC power supply 1 becomes V in FIG.
It is also determined whether or not it is 1 or more. When it is higher, the process returns to step 1, the switching pulse is stopped, and the protection operation is started. When the fixed time has elapsed in step 4, the process proceeds to step 6. In step 6, it is determined whether the external control signal at the external control signal output terminal T is equal to or higher than VTU in FIG. When it is equal to or higher than VTU, it is determined that the variable resistor 38 is externally connected, and in step 7, a switching pulse corresponding to the external control signal at the external control signal output terminal T is generated.

When the external control signal at the external control signal output terminal T is lower than VTU in FIG. 4 in step 6, it is determined that the variable resistor 38 is not connected to the outside, and in step 8 the internal control signal output terminal S is output. The switching pulse corresponding to the internal control signal of is generated. Next, in step 9, when the voltage of the AC power supply 1 is V1 or more, the process returns to step 1 to start the protective operation, but otherwise, the process returns to step 6 to continue the control. That is, even if the microcomputer 59 is used, it is possible to obtain the ventilation fan control device that performs the same function as in the first embodiment.

[0039]

As is apparent from the above description of the embodiments, according to the invention of claim 1, the bases of the respective transistors of the flywheel circuit depend on the polarity of the AC power source regardless of the switching operation of the switching circuit. Since a stable and continuous current flows alternately, and the base of each transistor can be driven sufficiently, a relatively large flywheel current can be made to flow, a large load can be controlled, and lightning Even if the surge propagates to the circuit, there are few failures.

According to the second aspect of the present invention, when the voltage of the AC power supply exceeds a certain value, the ventilation fan motor is stopped by the detection signal of the voltage detection means, so that even if the AC fan is erroneously connected to AC200V during construction. Since it does not operate, erroneous connections can be easily found, and since no voltage is applied to the circuit and the ventilation fan motor, these failures can be avoided in advance.

According to the third aspect of the present invention, when the external control means is connected and the external control is performed, the external control means and the speed control means are connected, and the internal control means and the speed control means are electrically separated from each other to perform the external control. Control becomes possible, and when the external control means is disconnected, the internal control means and the speed control means are electrically connected and controlled by the internal control means. The speed can be controlled by the external control means or the internal control means without the need for setting or the like.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a ventilation fan control device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing waveforms of respective parts of the circuit of the ventilation fan control device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an operation of the ventilation fan control device according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an operation of the ventilation fan control device according to the embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of a ventilation fan control device according to another embodiment of the present invention.

6 is a flowchart showing an operation of the ventilation fan control device of FIG.

FIG. 7 is a circuit configuration diagram of a conventional ventilation fan control device.

FIG. 8 is an explanatory diagram showing waveforms during operation of the conventional ventilation fan control device.

FIG. 9 is a connection configuration diagram of a conventional ventilation fan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Ventilation fan motor 3 Switching circuit 8 MOSFET 9 Flywheel circuit 10 Flaswheel circuit 11 Transistor 15 Resistor 16 Transistor 20 Resistor 21 Rectifying diode 22 Rectifying diode 25 Power supply voltage detection unit 30 Voltage comparator 35 Control voltage switching means 36 Voltage comparator 37 Sawtooth voltage generator 38 Variable resistor 48 Resistance 49 Transistor 54 Control signal switching means 57 Voltage comparator 58 Variable resistor

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[Procedure amendment]

[Submission date] February 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

One flywheel circuit 9 includes a transistor 11, a power supply line on the terminal Y side, and an error of the transistor 11.
A bias diode 12 inserted between the mitters ,
It is composed of protective diodes 13 and 14 connected in series to the collector and the emitter, and a resistor 15 for supplying a base current connected between the base of the transistor 11 and the AC power supply 1. The other flywheel circuit 10 includes a transistor 16 and a power supply line on the terminal Y side.
And a biasing diode 17 inserted between the emitter of the transistor 16 and the protection diode 18, 19 connected in series to the collector and the emitter, and between the base of the transistor 16 and the AC power supply 1. It is composed of a resistor 20 for supplying a base current. Resistors 15 and 2 in flywheel circuits 9 and 10
Rectification diodes 21 and 22 are connected in series to 0, and capacitors 23 and 24 are connected between the base and emitter of the transistors 11 and 16, respectively.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

Next, a half cycle in which the power input terminal W side is positive and the power input terminal V side is negative will be described.
While T8 is on, a current flows from the power input terminal W to the diode 12 , the emitter to the base of the transistor 11, the resistor 15, the rectifying diode 21 to the power input terminal V. In addition, while the MOSFET 8 is off, the path from the power supply input terminal W to the power supply input terminal V through the ventilation fan motor 2, the protection diode 14, the emitter of the transistor 11 to the base, the resistor 15, the rectifying diode 21. An electric current flows.

Claims (3)

[Claims] 1. A switching circuit connected in series between an AC power source and a ventilation fan motor so as to perform both positive and negative switching at a frequency higher than a power supply frequency, and a switching circuit connected in parallel to the ventilation fan motor for both positive and negative flywheels. A pair of flywheel transistors that perform wheeling and a control circuit that operates the switching circuit are provided, and the base of each transistor for the flywheel has the AC power supply regardless of the switching operation of the switching circuit. The ventilation fan control device is characterized in that a continuous current is made to flow from the AC power source alternately according to the polarity of the above. 2. A speed control means for controlling the speed of a ventilation fan motor operated by an AC power supply in multiple stages, a voltage detection means for detecting that the voltage of the AC power supply exceeds a certain value, and a detection by the voltage detection means. A ventilation fan control device comprising a ventilation fan stop means for stopping the supply of AC power to the ventilation fan motor in response to a signal. 3. A speed control means for controlling the speed of a ventilation fan motor operated by an AC power source in multiple stages, and a disconnection which is provided outside the ventilation fan and performs speed control by the speed control means from the outside via a control signal input terminal. It is possible to provide an external control means and an internal control means incorporated in a ventilation fan to control the speed by the speed control means, and by connecting the external control means, the external control means and the speed control means are connected to each other, and A ventilation fan control device, wherein an internal control means and the speed control means are electrically separated from each other, and by disconnecting the external control means, the internal control means and the speed control means are electrically connected to each other.