JPS62239895A - Control circuit for energizing degree of fan motor - Google Patents

Abstract

PURPOSE:To make the relation characteristic between energizing degree to a fan motor and the number of rotation linear, by setting the minimum unit of the energizing and unenergizing duration to the fan motor on a one AC cycle basis. CONSTITUTION:A zero-cross point detection circuit is composed of diodes 7 and 8, resistances 9, 10 and 12 as well as a transistor 11. A microcomputer 13 performs the timing of ON and OFF controlling the energizing duration output by the number of output pulses of a zero-cross voltage detection circuit on a cycle basis by the number of set-up zero-cross voltage detection pulses. On that account, the minimum unit of the energizing duration or unenergizing duration to a fan motor is set based on a cycle of an AC power source, so that the number of cycles energized on the positive side of the AC power source tallies with the number of cycles energized on the negative side and on deviation is found and that the DC braking is eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a fan motor energization rate that repeatedly energizes and de-energizes a fan motor according to a predetermined pattern and drives the fan motor at a rotation speed corresponding to the energization rate. This relates to control circuits.

[Prior Art] An example of this type of fan motor energization rate control circuit is the circuit shown in FIG. Further, conventional control is shown in FIGS. 4 and 5. FIG. 1 is a circuit diagram of a fan motor energization rate control circuit, FIG. 4 is an output waveform diagram of the circuit, and FIG. 5 is an explanatory diagram of the contents of a memory map in the electronic control circuit.

In FIG. 1, (1) is an AC100 commercial power supply, (2) is a fan motor, and (3) is a power transformer. (4) is a diode bridge, (5) is an electrolytic capacitor, and (6) is a three-terminal regulator. The diode bridge (4), electrolytic capacitor (5), and three-terminal regulator (6) constitute a constant voltage power supply circuit. ing.

(7) and (8) are diodes, (10) and (12) are resistors, and (11) are transistors 1 to 1, and the diodes (7) and (8) and the resistor (9)
and (10) and (12) and transistor (11)
The zero-cross detection circuit is configured by:

In other words, when A0100V + power supply (1) approaches zero cross, the potential difference between both ends of the secondary winding of the power transformer (3) becomes almost zero, so the potential at both terminals of this secondary winding becomes It becomes lower than the GND level on the output side of the diode bridge (4) (the negative terminal side of the electrolytic capacitor (5)).

Note that the GND level is always higher than the potential of the lower end of the secondary winding of the power transformer (3) by the forward voltage valve of the diode in the diode bridge (4). ing. Therefore, the diode (7
) and (8) are both reverse biased, and no base current can flow through the transistor (11). Therefore,
The transistor (11) is turned off and the pull-up resistor (
12), the collector potential of the transistor (11) becomes equal to the power supply voltage of the microcomputer (13) and becomes "')-1 (high level)".

When A0100V power supply (1) is not near zero cross,
The potential of either terminal of the secondary winding of the power transformer (3) becomes high, and base current flows through the diode (7) or (8) and resistor (9), causing the transistor (11
) is turned on, and its collector potential becomes on (GND level) and goes to a low level.

In this way, it is possible to detect whether the A0100V power supply (1) is near zero cross or not based on the collector potential of the transistor (11).

Further, (13) is a microcomputer that constitutes an electronic control circuit of the fan motor energization rate control circuit. (Pl
) is its power supply terminal, and the output (
VCC) is given.

(P2) is its ground terminal, which is connected to GND (OV). (P3) is its input terminal, which is the output terminal of the zero-cross detection circuit described above, that is, the transistor (11).
collector is connected.

(P4) is its output terminal and resistor! It is connected to the base of a resistor (19) and a transistor (20) via (18). (22a) is the light emitting side of the photo 1-LIAC coupler, and the light receiving side of the photo TRIAC coupler <
22b), and together constitute a phototriac coupler.

(P5) is an external input terminal for commanding the energization rate of the electronic control circuit constituted by the microcomputer (13), and in this embodiment, it is controlled by another microcomputer.

Here, the output terminal (P
4) becomes "H", the transistor (20) turns on, so a current flows through the resistor (21) to the light emitting side (22a) of the phototriac coupler, and the light receiving side (22a) of the phototriac coupler flows through the resistor (21). 22b) is turned on. As a result, the gate trigger circuit of the triac (27) formed by the resistors (23) and (24) is closed, and the triac (27), which constitutes a switching circuit together with the gate trigger circuit, is turned on, and the fan motor (2) is turned on.
is energized.

Output terminal (P4) of microcomputer (13) is L
'', the transistor (20) is off, so the trigger current does not flow to the light emitting side (22a) of the phototriac coupler, and the trigger current does not flow to the light receiving side (22b) of the phototriac coupler.
) turns off and opens the gate trigger circuit, so the triac (27) turns off. Therefore, the fan motor (2) is not energized. Also, (25) is a resistor, (26) is a capacitor, ]・Liac (2
7) constitutes the snubber circuit.

Next, the conventional control I operation of the fan motor energization rate control circuit will be explained using FIGS. 4 and 5.

In Figure 4, (28) is the power waveform of the AC 100V power supply (1), (29) is the input waveform at the input terminal (P3) of the microcomputer (13), and (32) is the output of the microphone [1 computer (13)]. The output waveform (33) at the terminal (P4) is a current waveform (energization waveform) energized to the fan motor (2). Further, FIG. 5 is a table showing the contents of a memory map in the electronic control circuit showing patterns for energizing the fan motor.

First, when the power supply waveform (28) is near the zero cross, the input terminal (P3) of the microcomputer (13) becomes 'l-1' due to the action of the zero cross detection circuit described above.When the power supply waveform (28) is not near the zero cross, the microcomputer The input terminal (P3) of (13) becomes °゛L''. Therefore, every half cycle of the power supply waveform (28), and
A pulse signal that becomes HTj near the zero cross is applied to the input terminal (P3) of the microcomputer (13) (this is the waveform shown in (29)).

The microcomputer (13) controls the fan motor (2), which is determined by other microcomputers based on control conditions such as time, temperature of the heat exchanger of the heater, etc.
The most appropriate energization rate for obtaining the rotational speed is selected, and in order to achieve that energization rate, the fan motor (2) is energized m+ according to the pattern of the memory map shown in FIG. In this embodiment C, the control of the energization rate is determined by a separate microcomputer, but the energization rate may be determined within the microcomputer (13).

This memory map pattern has a conduction rate of △ci
One unit is 12 cycles of the oov power supply (1), but the on/off switching is further divided into four, which is a unit of three cycles. For example, the energization rate is 83.
Considering the case of 3 [%], if only 10 cycles out of 12 cycles of AC 100V power supply are energized and the remaining 2 cycles are not energized, the energization rate is 10/12-0
゜833, so 2.5 to the fan motor (2)
Cycle on, 0.5 cycles off, 2.5 cycles on, 0.5 cycles off, 2.5 cycles on, 0.5 cycles off, 2.5 cycles on, 0.5 cycles・Repeated pattern of off (
2,5+2.5+2.5+2.5-10, so 10/
12=0.833). J'3, as an on/off switch, 12 Nicle is further divided into 3
The reason for using cycle units is that if the period of energization/de-energization of the fan motor (2) is long, the strength of the fan's wind will fluctuate and the wind will become pulsating. /This is to shorten the period of non-energization.

In addition, if a conduction rate of 20.8 [%] is required, 1"
Cycle on, 2 cycles off, 0.5 cycles on, 2.5 cycles off, 0.5 cycles on, 2.5 cycles off, 0.5 cycles on
Power is applied to the fan motor (2) in a repeating pattern of on, 2.5 cycles, and off. At this time, the number of energization cycles during 12 cycles is 1+0.5+0.5+0.
5-2.5, so the energization rate is 2.5/12=0.208
becomes.

Note that in the memory map pattern shown in FIG.
The total number of energization cycles in two cycles is divided into 20 half-cycles from 2.5 to 12, so the energization rate is from 20.8% (=2.5/12) to 100%.
](=12/12>) You can select from 20 levels.

The microcomputer (13) counts the number of cycles using the above-mentioned zero-cross signal, and also sets the output terminal (P4) to L'' at a timing synchronized with the zero-cross signal.
->"l-1", and then after a predetermined period of time, the output terminal (P4) is switched to ゛TOBI°→II L''.

That is, when the fan motor (2) is to be energized for a certain cycle, first, the output terminal (P4) is switched from °°L'' to ii H++ in synchronization with the zero-cross signal.

And from that time, for example, 6 [m5ec] later,
The output terminal (P4) is switched to °' H” - “L”. At this time, the time of 6 [m5 ccl is obtained by the timer built in the microcomputer (13). 3 [m5ec
1 period (power supply 60112 hours) or 1 Q [llll5
eC] period (when the power supply is 5Qllz), so after the output terminal (P4) changes from 'l-1' to ll LIT, the zero-cross signal is generated again after 2 or 3 [m5ccl or 4[+11SeC] has elapsed. The input is input to the microcomputer (13), and in synchronization with it, the output terminal (P4) is again switched from "L" to "Todo", and the 6 [m
After 5ec], it is switched from ゛tobi' to °``shi''. Such pulse output is continuously output for twice the required number of RFI cycles (because the zero-cross signal is input every half cycle). The gate of the triac 27) is triggered by the ``tobi'' signal at the output terminal <P4>, as described above. As mentioned above, this gate trigger signal turns off at 6[1113eC], but it is retriggered every zero cross signal, so while the output pulse of the output terminal (P4) is 'H', the triac (27) is conductive. state, and the fan motor (2) is energized.Also, the fan motor (2) can be de-energized by leaving the output terminal (P4) in the “sh” state even if the zero-cross signal is input. Yes, the number of cycles is counted by the Pirox L1 signal.

[Problems to be Solved by the Invention] Since the conventional fan motor energization rate control circuit is configured and controlled as described above, it has the following problems.

In other words, the cycle of energization/fault to the fan motor (2) is 3 cycles of the AC power supply, and the minimum unit of duration of the energized and non-energized parts is 0 of the AC power supply. .5 cycles, so the fan sweater (2) must be energized in one direction from the AC fi source.
For example, while it starts from the positive half-wave, energization to the fan motor (2) can end either during the positive half-wave or the negative half-wave. The number of energization cycles on the positive side and the negative side were different, and the number of energization cycles was sometimes biased toward one side, that is, the positive side or the negative side. For example, the energization rate is 83.3[
%], 2.5 cycles are energized every 3 cycles, so 6 cycles out of 10 out of 12 cycles are energized on the positive side of the AC power supply, resulting in 4 cycles. 2 cycles will be energized on the negative side, and 2 cycles will be biased on the positive side. Due to this bias, an excess amount of current is always applied on the positive side, which is equivalent to biasing a DC component to an AC current waveform, so when this is applied to the fan motor (2), It will work as an AM brake. That is, even if an energization rate of 83.3% is given, the rotation speed of the fan motor (2) will be lowered by the influence of the DC brake. However, for example, when the energization rate is 66.7%, energization is performed for 2 cycles every 3 cycles, so the number of energization cycles on the positive side and the number of energization cycles on the negative side are equal, and no bias occurs. The DC brake is not applied, and the fan motor (2) rotates at the expected rotation speed corresponding to the energization rate of 66.7%.

In other words, even if the energization rate changes by a certain amount, the way the DC brake is applied will differ depending on the output pattern, and if the DC brake is not applied, the planned rotational speed corresponding to the energization rate will be obtained. On the other hand, when the DC brake is applied, the rotational speed becomes lower than the planned rotational speed corresponding to the energization rate, and the rotational speed of the fan motor (2) does not change by a constant amount. In other words, there is a problem that the relationship between the energization rate and the rotational speed is not linear, but becomes a curved line with ups and downs.

This invention was made to solve the above problems, and provides a fan motor energization rate control circuit in which the relationship between the energization rate to the fan motor and the rotation speed of the fan motor has a linear characteristic. The purpose is to provide the following.

Means for Solving Problems] The fan motor energization rate control circuit according to the present invention turns on/off the energization duration output according to the number of output pulses of a zero-cross voltage detection circuit that detects the zero cross voltage of an AC power supply. An electronic control circuit that controls the timing of 61H in units of one cycle according to the set number of zero-cross voltage detection output pulses, and a turn-on and turn-off of a thyristor directly connected to the fan motor using the on/off control output of the electronic control circuit. It is equipped with a switching circuit for controlling.

[Function] In the fan motor energization rate control circuit according to the present invention, the minimum unit of the duration of energization or de-energization to the fan motor is one cycle of the AC power supply, so the number of energization cycles on the positive side of the AC power supply is The number of energization cycles on the negative side matches, and there is no bias towards only a specific polarity, so the DC brake is no longer applied to the fan motor, and the rotation speed of the fan motor is as planned by an amount corresponding to the energization rate. As a result, the relationship between the energization rate and the rotational speed is a smooth characteristic.

Embodiment] A fan motor energization rate control circuit according to an embodiment of the present invention will be described below. FIG. 1 is a circuit configuration diagram of a fan motor energization rate control circuit, and since it is exactly the same as that described in the description of the prior art, the description thereof will be omitted. FIG. 2 is an output waveform diagram of the circuit according to the embodiment of the present invention, and FIG. 3 is an explanatory diagram of the contents of a memory map in the electronic control circuit.

In FIG. 2, (28) is the power waveform of the AC 100V power supply (1), and (29) is the input waveform of the zero-cross signal at the input terminal (P3) of the microcomputer (13) at J3, which is the same as the conventional one. (30) is the output waveform applied to the output terminal (P4) of the microcomputer (13), (3
1) is a current waveform (energization waveform) energized to the fan motor (2).

FIG. 3 is a table showing a memory map pattern for energizing the fan motor (2).

The microcomputer (13) controls the control conditions, e.g.
In order to achieve the most appropriate energization rate to obtain the rotation speed of the fan motor (2), which is determined by the time and temperature of the heat exchanger (1), the fan Energize the motor (2). The pattern of this memory map is 8C100V electricity i1! which is grouped together as a conduction rate. (1) The number of cycles has been increased from the conventional 12 cycles to 24 cycles, and the on/off switching has been changed from 24 cycles to 4 cycles.
The split 6 cycles are in the middle.

For example, considering the case of energization rate of 83.3%, 5 cycles on, 1 cycle off, 5 cycles on, 1 cycle off, 5 cycles on,
The fan motor (2) is energized in the memory map pattern of 1 cycle off, 5 cycles on, and 1 cycle off. At this time, the number of energization cycles in 24 cycles is 5+5+5+5=20, so the energization rate is 20
/24=0.833.

In addition, if energization rate of 20.8% is required, 2 cycles on, 4 cycles off, 1 cycle on, 5 cycles off, 1 cycle on, 5 cycles off, 1 cycle on , with a memory map pattern of 5 cycles off, the fan motor (2
) is energized. At this time, the energization cycle in 24 cycles is 2 + 1 + 1 + 1 = 5, so the energization rate is 5/2
4=0.208.

Further, as shown in FIG. 3, the minimum unit of the number of energized and de-energized cycles is one cycle.

That is, there is no output in 0.5 cycle units such as 2.5 cycles on or 3.5't cycles off as in the conventional example (Fig. 5), but 3 cycles on or 4 cycles off. There is only an output of an integer number of cycles. For this reason,
The number of energization rate stages has been changed from the conventional example (20.8%) to 100%.
(20 steps up to %1), the number of cycles for calculating the energization rate is increased from the middle of 12 cycles in the conventional example to 24 cycles.

In the above embodiment, the switching circuit of the fan motor (2) is configured by turning on or turning off the triac (27) connected in series with the fan motor (2), but when carrying out the present invention, Not limited to the triac (27), puT, sc
R,sss.

It is applied to general thyristor circuits such as GTOlSUS and SBS.

Furthermore, in the above embodiment, the microcomputer (13)
The number of output pulses of the zero-cross voltage detection circuit is used to control the energization duration output on and off, but when implementing this invention, the microcomputer (13
), any electronic control circuit that can select and control a predetermined energization rate from a memory map may be used. However, in the conventional fan motor energization rate control circuit in which the electronic control circuit is composed of a microcomputer, control in units of one cycle can be solved by simply rewriting the memory map, so changing the microcomputer software is sufficient. Since it can be modified, it has the advantage that it can be done at the same cost as conventional ones.

"Effects of the Invention" As described above, the fan motor energization rate control circuit of the present invention controls the timing of on/off control of the energization duration output according to the number of output pulses of the zero-cross voltage detection circuit, depending on the set zero-cross voltage detection output. By using the electronic 1, II 60 circuit, which is performed in units of 1 cycle depending on the number of pulses, the minimum unit of continuous time or non-energized time to the fan motor is one cycle of the AC power supply, so on the positive side of the AC power supply. The number of energized cycles and the number of energized cycles on the negative side match and there is no bias, so there is no direct current brake that would adversely affect the rotational speed due to the bias. Therefore, as for the rotation speed of the fan motor, only the output corresponding to the given energization rate can be obtained as planned, so the relationship between the energization rate and the rotation speed has a linear characteristic, making it easier to control the rotation speed of the fan motor. .

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the fan motor energization rate control circuit, FIG. 2 is an output waveform diagram controlled by the circuit according to the embodiment of the present invention, and FIG. 3 is a diagram of the output waveform in the electronic control circuit of the embodiment of the present invention. FIG. 4 is an explanatory diagram of the contents of the memory map. FIG. 4 is an explanatory diagram of the operation of a conventional fan motor conduction rate control circuit. FIG. 5 is an explanatory diagram of the contents of the memory map in the conventional electronic control circuit. In the figure, (1) ・ACI OOV[t, (2)...Fan motor, (13)...Microcomputer, (22a)...
・Light-emitting side of phototriac coupler, (22b)...
・Phototriac coupler light receiving side, (27)...
Triac, is. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A zero-crossing voltage detection circuit that detects the zero-crossing voltage of the AC power source; and a zero-crossing voltage detection output pulse that controls the timing of on/off control of the energization duration output according to the number of output pulses of the zero-crossing voltage detection circuit. The fan motor is characterized by comprising: an electronic control circuit that performs the operation on a cycle-by-cycle basis depending on the number; and a switching circuit that controls turn-on and turn-off of a thyristor connected in series to the fan motor using the on/off control output of the electronic control circuit. Fan motor energization rate control circuit.