CN113864217A - Fan speed regulation method and system - Google Patents
Fan speed regulation method and system Download PDFInfo
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- CN113864217A CN113864217A CN202111064526.2A CN202111064526A CN113864217A CN 113864217 A CN113864217 A CN 113864217A CN 202111064526 A CN202111064526 A CN 202111064526A CN 113864217 A CN113864217 A CN 113864217A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R19/175—Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
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Abstract
The invention provides a fan speed regulation method and a system, comprising the following steps: receiving a third signal; controlling the rotating speed of the fan according to the distribution of the level state of the third signal; the third signal is determined based on a comparison of the magnitudes of the first and second signals. The fan speed regulating method and the fan speed regulating system provided by the invention control the driving and power-off time of the fan in the running process according to the third signal, further realize the speed regulation of the fan in the strong current circuit, have good starting characteristics, and have the advantages of small volume, high safety and greatly reduced electric energy loss.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a fan speed regulation method and system.
Background
With the wide application of various fan application devices, the speed regulation of the fan is indispensable.
The existing speed regulating circuit for the alternating current fan is directly connected in series in an alternating current loop, a direct current contactor with large volume and a potentiometer with large power consumption are needed, and the potentiometer is directly connected with a geothermal system.
Therefore, the existing speed regulating circuit has the problems of high energy consumption, insecurity and poor starting performance of the fan.
Disclosure of Invention
Aiming at the problems in the prior art, the embodiment of the invention provides a fan speed regulation method and system.
The invention provides a fan speed regulation method, which comprises the following steps: receiving a third signal; controlling the rotating speed of the fan according to the distribution of the level state of the third signal; the third signal is determined based on a comparison of the magnitudes of the first and second signals.
According to the fan speed regulating method provided by the invention, the rotating speed of the fan is controlled according to the distribution of the level state of the third signal, and the method comprises the following steps: determining a level state of the third signal at any one time; under the condition that the level state of the third signal is high level, connecting a first power supply with the fan to drive the fan to operate; and cutting off the connection between the first power supply and the fan under the condition that the level state of the third signal is low level and the voltage signal of the first power supply crosses zero.
According to the speed regulation method of the fan, provided by the invention, the first signal is obtained by a first circuit according to the voltage signal of the first power supply; wherein the first circuit comprises: a zero-crossing detection circuit and a sawtooth wave forming circuit; the input end of the zero-crossing detection circuit is used for receiving a voltage signal sent by the first power supply; the input end of the sawtooth wave forming circuit is used for receiving the direct current signal output by the zero-crossing detection circuit; the output end of the sawtooth wave forming circuit is used for outputting the first signal; the first signal is a sawtooth wave signal.
According to the speed regulation method of the fan provided by the invention, the zero-crossing detection circuit comprises: the current limiting resistor R1, the full bridge circuit D1, the photoelectric coupler OP1 and the pull-up resistor R3; the pin No. 1 of the full-bridge circuit D1 is connected with the pin No. 1 of the photoelectric coupler OP 1; the No. 2 pin of the full-bridge circuit D1 forms one input end of the zero-crossing detection circuit and is connected with the negative electrode of the first power supply; the pin 3 of the full-bridge circuit D1 is connected with the pin 2 of the photoelectric coupler OP 1; the pin 4 of the full-bridge circuit D1 is connected with one end of the current-limiting resistor R1; the other end of the current-limiting resistor R1 forms the other input end of the zero-crossing detection circuit and is connected with the anode of the first power supply; a No. 4 pin of the photoelectric coupler OP1 is connected with one end of the pull-up resistor R3 to form an output end of the zero-crossing detection circuit; the other end of the pull-up resistor R3 is connected with the anode of a second power supply; the pin 3 of the photoelectric coupler OP1 is grounded.
According to the speed regulation method of the fan provided by the invention, the sawtooth wave forming circuit comprises: the voltage comparator U1A, a resistor R2, a resistor R11, a resistor R4, a triode Q3, a resistor R9 and a capacitor C2; the No. 2 pin of the voltage comparator U1A is an inverted end, and forms the input end of the sawtooth wave forming circuit; the No. 3 pin of the voltage comparator U1A is a positive end and is simultaneously connected with one end of the resistor R2, one end of the resistor R11 and one end of the resistor R4; the other end of the resistor R4 is simultaneously connected with the pin No. 2 of the triode Q3 and the pin No. 1 of the voltage comparator U1A; the other end of the resistor R2 and the No. 8 pin of the voltage comparator U1A are simultaneously connected with the anode of the second power supply; the other end of the resistor R11, the pin No. 4 of the voltage comparator U1A, one end of the capacitor C2 and the pin No. 1 of the triode Q3 are grounded; the pin No. 3 of the triode Q3 is connected with one end of the resistor R9; the other end of the resistor R9 is connected with the anode of the second power supply; and a pin 3 of the triode Q3 is connected with the other end of the capacitor C2 to form an output end of the sawtooth wave forming circuit.
According to the fan speed regulation method provided by the invention, the second signal is obtained by the second circuit according to the pulse width modulation signal; the second signal is a direct current voltage signal; the second circuit includes: a filter circuit; the filter circuit receives the pulse width modulation signal output by a signal output interface of the central processing unit; the output end of the filter circuit forms the output end of the second circuit; the filter circuit includes: the resistor R16, the resistor R17, the capacitor C4 and the capacitor C5; the signal output interface of the central processing unit is connected with one end of the resistor R16; one end of the resistor R16 forms the input end of the filter circuit and is connected with the signal output interface of the central processing unit; the other end of the resistor R17 is connected with one end of the capacitor C5 to form the output end of the filter circuit; the other end of the capacitor C4 and the other end of the capacitor C5 are grounded.
According to the fan speed regulation method provided by the invention, the third signal is obtained based on the third circuit; the third circuit includes: the circuit comprises a resistor R14, a resistor R8, a resistor R6, a voltage comparator U1B, a triode Q1 and a resistor R10; the No. 5 pin of the voltage comparator U1B is used as a positive end, and is simultaneously connected with one end of the resistor R8 and one end of the resistor R6; the other end of the resistor R8 forms an input end of the third circuit and is connected with the output end of the first circuit; the other end of the resistor R6 is simultaneously connected with a pin No. 7 of the voltage comparator U1B, one end of a pull-up resistor R5 and a pin No. 2 of the triode Q1; the other end of the pull-up resistor R5 is simultaneously connected with one end of a capacitor C1, a pin No. 1 of the triode Q1 and the anode of a second power supply; the other end of the capacitor C1 is grounded; the No. 6 pin of the voltage comparator U1B is used as an inverted terminal and is connected with one end of the resistor R14; the other end of the resistor R14 forms the other input end of the third circuit and is connected with the output end of the second circuit; and a pin 3 of the triode Q1 is connected with one end of the resistor R10, and the other end of the resistor R10 forms the output end of the third circuit.
According to the fan speed regulation method provided by the invention, a third signal is received, the rotating speed of the fan is controlled according to the distribution of the level state of the third signal, and the fan speed regulation method is realized based on a fourth circuit; the fourth circuit includes: the circuit comprises a photoelectric coupler U2, a resistor R12, a bidirectional thyristor Q2, a resistor R15, a resistor R18, a resistor R13 and a capacitor C3; a pin No. 1 of the photoelectric coupler U2 is connected with one end of the resistor R12 to form an input end of the fourth circuit; the other end of the resistor R12 and a No. 2 pin of the photoelectric coupler U2 are grounded; the No. 6 pin of the photoelectric coupler U2 is simultaneously connected with the anode of a first power supply, the No. 2 pin of the bidirectional thyristor Q2 and one end of the resistor R13; the No. 4 pin of the photoelectric coupler U2 is connected with one end of the resistor R15; the other end of the resistor R15 is simultaneously connected with the No. 3 pin of the bidirectional thyristor Q2 and one end of the resistor R18; the other end of the resistor R18 is simultaneously connected with the pin No. 1 of the bidirectional thyristor Q2 and one end of the capacitor C3 to form the output end of the fourth circuit; the other end of the capacitor C3 is connected with the other end of the resistor R13.
According to the fan speed regulation method provided by the invention, the voltage phase of the first signal is the same as that of the pulse width modulation signal; for any moment, if the amplitude comparison result shows that the amplitude of the first signal is higher than that of the second signal, the third signal is at a high level; and if the amplitude comparison result shows that the amplitude of the first signal is not higher than the amplitude of the second signal, the third signal is at a low level.
The invention also provides a fan speed control system, comprising: the receiving control unit is used for receiving a third signal and controlling the rotating speed of the fan according to the distribution of the level state of the third signal; the third signal is determined based on a comparison of the magnitudes of the first and second signals.
The fan speed regulating method and the fan speed regulating system provided by the invention control the driving and power-off time of the fan in the running process according to the third signal, further realize the speed regulation of the fan in the strong current circuit, have good starting characteristics, and have the advantages of small volume, high safety and greatly reduced electric energy loss.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a fan speed control method provided by the present invention;
FIG. 2 is a schematic structural diagram of a fan speed regulation circuit provided by the present invention;
FIG. 3 is a second schematic flow chart of a fan speed control method according to the present invention;
FIG. 4 is a waveform diagram illustrating a fan speed control method according to the present invention;
fig. 5 is a schematic structural diagram of a fan speed control system provided by the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that in the description of the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The terms "upper", "lower", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The traditional speed regulating circuit is directly connected in series in an alternating current loop, the starting performance of a fan is poor, and a potentiometer is directly connected with a hot ground system and is very unsafe; large electric energy loss and low safety. Even depending on manual adjustment, automatic control cannot be achieved.
The following describes a fan speed regulation method and system provided by an embodiment of the invention with reference to fig. 1 to 5.
Fig. 1 is a schematic flow chart of a fan speed control method provided by the present invention, and its executing main bodies are all fourth circuits without emphasis, as shown in fig. 1, including but not limited to the following steps:
first, in step S1, the fourth circuit receives the third signal.
Further, in step S2, controlling the rotation speed of the fan according to the distribution of the level state of the third signal; the third signal is determined based on a comparison of the magnitudes of the first and second signals.
The fan may be a single-phase ac fan or a three-phase ac fan, and in the following embodiments of the present invention, the single-phase ac fan is taken as an example for description, which is not to be construed as a limitation to the protection scope of the present invention.
The working power supply of the fan is a first power supply, and the first power supply can be 220V single-phase alternating current.
The first signal can be a sawtooth wave signal, the second signal can be a direct current voltage signal and is used as a reference voltage, the first signal can be fixed and unchanged, and the duty ratio of the third signal is adjusted by adjusting the amplitude of the second signal. In the embodiment of the present invention, the amplitude is an amplitude of the voltage signal, and the amplitude comparison result may be a result of the amplitude of the first signal being greater than the amplitude of the second signal.
Under the condition that the level state of the third signal is high level, the fourth circuit is connected between the first power supply and the fan to drive the fan to operate; and under the condition that the level state of the third signal is low level, the fourth circuit cuts off the connection between the first power supply and the fan.
The fourth circuit controls the time of driving and power-off in the running process of the fan, so that the speed of the fan is regulated.
The fan speed regulating method provided by the invention controls the driving and power-off time of the fan in the operation process according to the third signal, further realizes the speed regulation of the fan in the strong current circuit, has good starting characteristics, and has the advantages of small volume, high safety and greatly reduced electric energy loss.
Optionally, controlling the rotation speed of the fan according to the distribution of the level state of the third signal includes:
determining a level state of the third signal at any one time;
under the condition that the level state of the third signal is high level, connecting a first power supply with the fan to drive the fan to operate;
and cutting off the connection between the first power supply and the fan under the condition that the level state of the third signal is low level.
Fig. 2 is a schematic structural diagram of the fan speed control circuit provided by the present invention, and as shown in fig. 2, the positive pole of the first power source is denoted as AC220_ L, and the negative pole of the first power source is denoted as AC220_ N; the second power supply may be a 12V dc power supply.
Under the condition that the level state of the third signal is high level, the pin No. 2 and the pin No. 3 of the bidirectional triode thyristor Q2 are conducted, and the connection between the first power supply and the fan is switched on to drive the fan to operate; and under the condition that the level state of the third signal is low level, a medium is arranged between the No. 2 pin and the No. 3 pin of the bidirectional triode thyristor Q2, and the connection between the first power supply and the fan is cut off.
According to the fan speed regulating method provided by the invention, the driving and power-off time of the fan in the operation process is controlled through the third signal, so that the speed regulation of the fan in the strong current circuit is realized.
Optionally, the first signal is obtained by a first circuit according to a voltage signal of the first power supply;
wherein the first circuit comprises: a zero-crossing detection circuit and a sawtooth wave forming circuit;
the input end of the zero-crossing detection circuit is used for receiving a voltage signal sent by the first power supply; the input end of the sawtooth wave forming circuit is used for receiving the direct current signal output by the zero-crossing detection circuit; the output end of the sawtooth wave forming circuit is used for outputting the first signal; the first signal is a sawtooth wave signal.
The period of the first signal is about half of the period of the voltage signal provided by the first power supply, and accordingly, the frequency of the first signal is about twice the frequency of the voltage signal provided by the first power supply.
In the running process of the fan speed regulating circuit, the sawtooth wave signal is linearly boosted along with time in one period, so that the duty ratio of the third signal can be linearly changed by adjusting the amplitude of the second signal, and the stable speed regulation of the fan is further realized.
According to the fan speed regulation method provided by the invention, the voltage signal of the first power supply is converted into the sawtooth wave signal through the first circuit, so that the fan is stably regulated.
Optionally, the zero-crossing detection circuit includes: the current limiting resistor R1, the full bridge circuit D1, the photoelectric coupler OP1 and the pull-up resistor R3;
the pin No. 1 of the full-bridge circuit D1 is connected with the pin No. 1 of the photoelectric coupler OP 1;
the No. 2 pin of the full-bridge circuit D1 forms one input end of the zero-crossing detection circuit and is connected with the negative electrode of the first power supply;
the pin 3 of the full-bridge circuit D1 is connected with the pin 2 of the photoelectric coupler OP 1;
the pin 4 of the full-bridge circuit D1 is connected with one end of the current-limiting resistor R1;
the other end of the current-limiting resistor R1 forms the other input end of the zero-crossing detection circuit and is connected with the anode of the first power supply;
a No. 4 pin of the photoelectric coupler OP1 is connected with one end of the pull-up resistor R3 to form an output end of the zero-crossing detection circuit;
the other end of the pull-up resistor R3 is connected with the anode of a second power supply; the pin 3 of the photoelectric coupler OP1 is grounded.
Specifically, the first power supply inputs voltage signals from the pin No. 2 and the pin No. 4 of the full-bridge circuit D1, and the voltage signals are single-phase alternating current and have directivity and two zero-crossing points, so that the voltage signals are rectified by the full-bridge circuit D1, the negative half period of the voltage signals is inverted to be positive, the rectified voltage signals are rectified to be pulsating direct current signals, and the zero-crossing pulse signals are output after being isolated by the photoelectric coupler OP 1.
The current limiting resistor R1 can limit the current of the first power supply, so that the elements in the fan speed regulating circuit are prevented from being damaged by overlarge current.
According to the fan speed regulation method provided by the invention, the zero-crossing detection circuit is utilized to carry out voltage reduction and rectification processing on the alternating voltage signal of the first power supply so as to obtain the zero-crossing pulse signal and provide a basis for forming the sawtooth wave signal.
Optionally, the sawtooth wave forming circuit includes: the voltage comparator U1A, a resistor R2, a resistor R11, a resistor R4, a triode Q3, a resistor R9 and a capacitor C2;
the No. 2 pin of the voltage comparator U1A is an inverted end, and forms the input end of the sawtooth wave forming circuit;
the No. 3 pin of the voltage comparator U1A is a positive end and is simultaneously connected with one end of the resistor R2, one end of the resistor R11 and one end of the resistor R4;
the other end of the resistor R4 is simultaneously connected with the pin No. 2 of the triode Q3 and the pin No. 1 of the voltage comparator U1A;
the other end of the resistor R2 and the No. 8 pin of the voltage comparator U1A are simultaneously connected with the anode of the second power supply;
the other end of the resistor R11, the pin No. 4 of the voltage comparator U1A, one end of the capacitor C2 and the pin No. 1 of the triode Q3 are grounded;
the pin No. 3 of the triode Q3 is connected with one end of the resistor R9;
the other end of the resistor R9 is connected with the anode of the second power supply;
and a pin 3 of the triode Q3 is connected with the other end of the capacitor C2 to form an output end of the sawtooth wave forming circuit.
The resistor R2 and the resistor R11 form a voltage dividing circuit, and the voltage dividing point of the voltage dividing circuit, namely the voltage of the access terminal of the No. 3 pin of the voltage comparator U1A, is a zero-crossing reference voltage.
The pin 2 of the voltage comparator U1A is connected to the zero-crossing pulse signal, and when the zero-crossing pulse signal is higher than the zero-crossing reference voltage, the pin 1 of the voltage comparator U1A serves as an output terminal and outputs a low level. Otherwise, a high level is output to form a rectangular wave signal.
The resistor R4 is a positive feedback resistor, and is used for adjusting the voltage of the in-phase terminal as required, so as to ensure the stability of the voltage of the output terminal of the voltage comparator U1A and prevent jitter.
The triode Q3 is a PMOS triode, and is in a conducting state during the period when the rectangular wave signal output by the voltage comparator U1A is at a low level, and at this time, the charge on the capacitor C2 is rapidly discharged; when the rectangular wave signal output by the voltage comparator U1A is at a high level, it is in an off state, the capacitor C2 is slowly charged by the common 12V dc voltage of the second power supply through the resistor R9, and the voltage on the capacitor C2 gradually increases to form a sawtooth wave signal.
According to the fan speed regulation method provided by the invention, the sawtooth wave forming circuit is utilized to generate a sawtooth wave signal according to the zero-crossing pulse signal and the reference voltage, so that the stable speed regulation of the fan is realized.
Optionally, the second signal is obtained by the second circuit according to a pulse width modulation signal; the second signal is a direct current voltage signal;
the second circuit includes: a filter circuit;
the filter circuit receives the pulse width modulation signal output by a signal output interface of the central processing unit;
the output end of the filter circuit forms the output end of the second circuit;
the filter circuit may be a two-stage RC filter circuit, and at least includes: the resistor R16, the resistor R17, the capacitor C4 and the capacitor C5;
the signal output interface of the central processing unit is connected with one end of the resistor R16;
one end of the resistor R16 forms the input end of the filter circuit and is connected with the signal output interface of the central processing unit;
the other end of the resistor R17 is connected with one end of the capacitor C5 to form the output end of the filter circuit;
the other end of the capacitor C4 and the other end of the capacitor C5 are grounded.
A signal output interface of the Central Processing Unit (CPU) outputs a Pulse Width Modulation (PWM) signal.
The invention adjusts the width or duty ratio of the PWM signal to regulate the amplitude of the second signal: the two-stage RC filter circuit is used for converting the PWM signal output by the CPU into a direct-current voltage signal, and outputting the direct-current voltage signal to the third circuit as a second signal.
Wherein, the amplitude of the direct current voltage signal is in direct proportion to the duty ratio of the PWM signal.
According to the fan speed regulation method provided by the invention, the amplitude of the direct current voltage signal is further regulated by regulating the duty ratio of the pulse width modulation signal, so that the stable speed regulation of the fan is realized.
Optionally, the third signal is obtained based on a third circuit;
the third circuit includes: the circuit comprises a resistor R14, a resistor R8, a resistor R6, a voltage comparator U1B, a triode Q1 and a resistor R10;
the No. 5 pin of the voltage comparator U1B is used as a positive end, and is simultaneously connected with one end of the resistor R8 and one end of the resistor R6;
the other end of the resistor R8 forms an input end of the third circuit and is connected with the output end of the first circuit;
the other end of the resistor R6 is simultaneously connected with a pin No. 7 of the voltage comparator U1B, one end of a pull-up resistor R5 and a pin No. 2 of the triode Q1;
the other end of the pull-up resistor R5 is simultaneously connected with one end of a capacitor C1, a pin No. 1 of the triode Q1 and the anode of a second power supply;
the other end of the capacitor C1 is grounded;
the No. 6 pin of the voltage comparator U1B is used as an inverted terminal and is connected with one end of the resistor R14;
the other end of the resistor R14 forms the other input end of the third circuit and is connected with the output end of the second circuit;
and a pin 3 of the triode Q1 is connected with one end of the resistor R10, and the other end of the resistor R10 forms the output end of the third circuit.
The third circuit compares and amplifies the first signal and the second signal to obtain a third signal which is used as a trigger signal of the fourth circuit.
The positive electrode of the capacitor C1 is connected to the positive electrode of the second power supply, and the negative electrode of the capacitor C1 is grounded, so that the second power supply can be stabilized.
The third circuit compares the amplitude of the first signal with the amplitude of the second signal, and since the first signal is only related to the voltage characteristic of the first power supply and can be regarded as fixed, the duty ratio of the acquired third signal is different when the amplitudes of the second signals are different.
The first signal is applied to the in-phase terminal of the U1B through the resistor R8, the second signal is applied to the out-phase terminal of the U1B through the resistor R14, when the amplitude of the first signal is higher than that of the second signal, the pin No. 7 of the voltage comparator U1B outputs a high level, otherwise, the pin No. 7 of the voltage comparator U1B outputs a low level, so that the signal output by the pin No. 7 of the voltage comparator U1B is a rectangular wave, and the rectangular wave generates a third signal with a large driving capability through the transistor Q1 to drive the fourth circuit.
The transistor Q1 is a common emitter mode transistor.
According to the fan speed regulating method provided by the invention, the amplitude values of the first signal and the second signal are compared through the third circuit to form periodic rectangular wave voltage for realizing the control of the rotating speed of the fan.
Optionally, receiving a third signal, controlling the rotation speed of the fan according to the distribution of the level state of the third signal, and implementing the control based on a fourth circuit;
the fourth circuit includes: the circuit comprises a photoelectric coupler U2, a resistor R12, a bidirectional thyristor Q2, a resistor R15, a resistor R18, a resistor R13 and a capacitor C3;
a pin No. 1 of the photoelectric coupler U2 is connected with one end of the resistor R12 to form an input end of the fourth circuit;
the other end of the resistor R12 and a No. 2 pin of the photoelectric coupler U2 are grounded;
the No. 6 pin of the photoelectric coupler U2 is simultaneously connected with the anode of a first power supply, the No. 2 pin of the bidirectional thyristor Q2 and one end of the resistor R13;
the No. 4 pin of the photoelectric coupler U2 is connected with one end of the resistor R15;
the other end of the resistor R15 is simultaneously connected with the No. 3 pin of the bidirectional thyristor Q2 and one end of the resistor R18;
the other end of the resistor R18 is simultaneously connected with the pin No. 1 of the bidirectional thyristor Q2 and one end of the capacitor C3 to form the output end of the fourth circuit;
the other end of the capacitor C3 is connected with the other end of the resistor R13.
Photoelectric isolation devices are arranged in the first circuit and the fourth circuit to isolate the fan speed regulation circuit from the first power supply, photoelectric isolation of weak current and strong current is achieved, and the fan is automatically and stably regulated in speed by controlling the strong current through the weak current.
For the voltage signal output by the first power supply, the conduction duration of the fourth circuit in each half alternating voltage period is different along with the difference of the duty ratio of the third signal, so that the average voltage of the fan in the whole working time is different, and the speed regulation effect of the fan is further realized.
Under the condition that the voltage state of the third signal is high level, the No. 6 pin and the No. 4 pin of the photoelectric coupler U2 are conducted, so that a voltage signal output by the anode of the first power supply applies trigger voltage to the No. 3 pin of the bidirectional triode thyristor Q2 through the resistor R15, the No. 2 pin and the No. 1 pin of the bidirectional triode thyristor Q2 are conducted, and the fan M is electrified; at the moment when the third signal is changed from the high level to the low level, because the period of the third signal is about half of that of the voltage signal of the first power supply, at the moment, the voltage signal of the first power supply crosses the zero point, the bidirectional thyristor Q2 is cut off, the bidirectional thyristor Q2 is continuously cut off in the time period when the third signal is at the low level, so that the fan M is continuously de-energized, until the third signal is changed to the high level, the bidirectional thyristor Q2 is turned on again, and the fan M is not energized again.
In the speed regulation process of the fan, the duty ratio of a PWM signal is controlled by a CPU to regulate the amplitude of a second signal so as to influence the duty ratio of a third signal, the duty ratio of the third signal determines the time length from cut-off to conduction of a bidirectional thyristor Q2 in a fourth circuit, the fan M is not electrified in the time length from cut-off to conduction of the bidirectional thyristor Q2, the rotating speed of the fan M can be influenced, and the automatic control of the fan M is finally realized.
Due to the characteristics of the controllable silicon, the voltage signal of the first power supply is automatically closed at the zero-crossing moment and then is conducted again when the next trigger moment is reached. The chopper element protection is formed by the resistor R13 and the capacitor C3, the counter-induction electromotive force of the fan M at the moment of turning off the bidirectional thyristor Q2 is absorbed, and the bidirectional thyristor Q2 is prevented from being broken down, so that the circuit is protected.
According to the fan speed regulating method provided by the invention, the third signal is utilized to control the driving and power-off time of the fan in the operation process, so that the speed regulation of the fan in the strong current circuit is realized.
Optionally, the voltage phase of the first signal and the pulse width modulation signal is the same;
for any moment, if the amplitude comparison result shows that the amplitude of the first signal is higher than that of the second signal, the third signal is at a high level;
and if the amplitude comparison result shows that the amplitude of the first signal is not higher than the amplitude of the second signal, the third signal is at a low level.
Fig. 3 is a second schematic flow chart of the fan speed control method according to the present invention, as shown in fig. 3, on one hand, the alternating voltage signal of the first power source completes the formation of the sawtooth wave signal by the alternating current zero crossing detection and the sawtooth wave pulse formation; on the other hand, the PWM pulse converts a direct current voltage signal by controlling the PWM signal and the reference voltage formation by the CPU.
And further, according to the sawtooth wave signal and the direct current voltage signal, a comparison amplification pulse is obtained, so that the silicon controlled rectifier is controlled to be conducted and triggered, alternating current chopping is carried out, and the automatic and stable speed regulation of the fan is realized.
Fig. 4 is a waveform schematic diagram of the fan speed regulating method provided by the present invention, as shown in fig. 4, the first signal is a sawtooth wave signal, the second signal is a direct current voltage signal, the zero-crossing pulse signal is collected at pin 4 of the photocoupler OP1, and the output waveform is collected at pin 4 of the photocoupler U2. The frequency of the first power supply is 50Hz, and the frequencies of the first signal, the second signal, the zero-crossing pulse signal and the output waveform are all theta 99.8043Hz, which is about twice the frequency of the first power supply.
As can be seen from fig. 4, when the amplitude of the first signal changes from lower to higher than the amplitude of the second signal, which is an output start time, the output waveform changes from low level to high level, which is an output start point of the fan M, and when the output waveform is at high level, the first power supply continuously drives the fan M; at the zero-crossing point of the zero-crossing pulse signal, the output is turned from high level to low level, the connection between the first power supply and the fan M is cut off when the output waveform is in the high level state, and the fan M loses power.
Fig. 5 is a schematic structural diagram of a fan speed control system provided in the present invention, as shown in fig. 5, the fan speed control system at least includes:
a receiving unit 501, configured to receive a third signal;
a control unit 502, configured to control a rotation speed of the fan according to the distribution of the level state of the third signal;
the third signal is determined based on a comparison of the magnitudes of the first and second signals.
In the running process of the system, the receiving unit 501 receives a third signal, and the control unit 502 controls the rotating speed of the fan according to the distribution of the level state of the third signal; the third signal is determined based on a comparison of the magnitudes of the first and second signals.
The working power supply of the fan is a first power supply, and the first power supply can be 220V single-phase alternating current.
The first signal can be a sawtooth wave signal, the second signal can be a direct current voltage signal and is used as a reference voltage, the first signal can be fixed and unchanged, and the duty ratio of the third signal is adjusted by adjusting the amplitude of the second signal.
Under the condition that the level state of the third signal is high level, the fourth circuit is connected between the first power supply and the fan to drive the fan to operate; and under the condition that the level state of the third signal is low level, the fourth circuit cuts off the connection between the first power supply and the fan.
The fourth circuit controls the time of driving and power-off in the running process of the fan, so that the speed of the fan is regulated.
According to the fan speed regulating system provided by the invention, the automatic and stable speed regulation of the fan is realized by controlling strong current with weak current, the fan speed regulating system has good starting characteristic, and a direct current contactor with large volume and a rheostat with large power consumption are omitted, so that the circuit volume and the electric energy loss are greatly reduced.
It should be noted that, in specific execution, the fan speed control system provided in the embodiment of the present invention may be implemented based on the fan speed control method described in any of the above embodiments, and details of this embodiment are not described herein.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A fan speed regulation method is characterized by comprising the following steps:
receiving a third signal;
controlling the rotating speed of the fan according to the distribution of the level state of the third signal;
the third signal is determined based on a comparison of the magnitudes of the first and second signals.
2. The fan speed control method according to claim 1, wherein controlling the rotation speed of the fan according to the distribution of the level state of the third signal comprises:
determining a level state of the third signal at any one time;
under the condition that the level state of the third signal is high level, connecting a first power supply with the fan to drive the fan to operate;
and cutting off the connection between the first power supply and the fan under the condition that the level state of the third signal is low level and the voltage signal of the first power supply crosses zero.
3. The fan speed control method according to claim 2, wherein the first signal is obtained by a first circuit according to a voltage signal of the first power supply;
wherein the first circuit comprises: a zero-crossing detection circuit and a sawtooth wave forming circuit;
the input end of the zero-crossing detection circuit is used for receiving a voltage signal sent by the first power supply;
the input end of the sawtooth wave forming circuit is used for receiving the direct current signal output by the zero-crossing detection circuit;
the output end of the sawtooth wave forming circuit is used for outputting the first signal; the first signal is a sawtooth wave signal.
4. The fan speed regulation method of claim 3, wherein the zero-crossing detection circuit comprises: the current limiting resistor R1, the full bridge circuit D1, the photoelectric coupler OP1 and the pull-up resistor R3;
the pin No. 1 of the full-bridge circuit D1 is connected with the pin No. 1 of the photoelectric coupler OP 1;
the No. 2 pin of the full-bridge circuit D1 forms one input end of the zero-crossing detection circuit and is connected with the negative electrode of the first power supply;
the pin 3 of the full-bridge circuit D1 is connected with the pin 2 of the photoelectric coupler OP 1;
the pin 4 of the full-bridge circuit D1 is connected with one end of the current-limiting resistor R1;
the other end of the current-limiting resistor R1 forms the other input end of the zero-crossing detection circuit and is connected with the anode of the first power supply;
a No. 4 pin of the photoelectric coupler OP1 is connected with one end of the pull-up resistor R3 to form an output end of the zero-crossing detection circuit;
the other end of the pull-up resistor R3 is connected with the anode of a second power supply;
the pin 3 of the photoelectric coupler OP1 is grounded.
5. The fan speed regulation method according to claim 4, wherein the sawtooth wave forming circuit comprises: the voltage comparator U1A, a resistor R2, a resistor R11, a resistor R4, a triode Q3, a resistor R9 and a capacitor C2;
the No. 2 pin of the voltage comparator U1A is an inverted end, and forms the input end of the sawtooth wave forming circuit;
the No. 3 pin of the voltage comparator U1A is a positive end and is simultaneously connected with one end of the resistor R2, one end of the resistor R11 and one end of the resistor R4;
the other end of the resistor R4 is simultaneously connected with the pin No. 2 of the triode Q3 and the pin No. 1 of the voltage comparator U1A;
the other end of the resistor R2 and the No. 8 pin of the voltage comparator U1A are simultaneously connected with the anode of the second power supply;
the other end of the resistor R11, the pin No. 4 of the voltage comparator U1A, one end of the capacitor C2 and the pin No. 1 of the triode Q3 are grounded;
the pin No. 3 of the triode Q3 is connected with one end of the resistor R9;
the other end of the resistor R9 is connected with the anode of the second power supply;
and a pin 3 of the triode Q3 is connected with the other end of the capacitor C2 to form an output end of the sawtooth wave forming circuit.
6. The fan speed control method according to claim 4, wherein the second signal is obtained by the second circuit according to a pulse width modulation signal; the second signal is a direct current voltage signal;
the second circuit includes: a filter circuit;
the filter circuit receives the pulse width modulation signal output by a signal output interface of the central processing unit;
the output end of the filter circuit forms the output end of the second circuit;
the filter circuit includes: the resistor R16, the resistor R17, the capacitor C4 and the capacitor C5;
the signal output interface of the central processing unit is connected with one end of the resistor R16;
one end of the resistor R16 forms the input end of the filter circuit and is connected with the signal output interface of the central processing unit;
the other end of the resistor R17 is connected with one end of the capacitor C5 to form the output end of the filter circuit;
the other end of the capacitor C4 and the other end of the capacitor C5 are grounded.
7. The fan speed control method according to claim 6, wherein the third signal is obtained based on a third circuit;
the third circuit includes: the circuit comprises a resistor R14, a resistor R8, a resistor R6, a voltage comparator U1B, a triode Q1 and a resistor R10;
the No. 5 pin of the voltage comparator U1B is used as a positive end, and is simultaneously connected with one end of the resistor R8 and one end of the resistor R6;
the other end of the resistor R8 forms an input end of the third circuit and is connected with the output end of the first circuit;
the other end of the resistor R6 is simultaneously connected with a pin No. 7 of the voltage comparator U1B, one end of a pull-up resistor R5 and a pin No. 2 of the triode Q1;
the other end of the pull-up resistor R5 is simultaneously connected with one end of a capacitor C1, a pin No. 1 of the triode Q1 and the anode of a second power supply;
the other end of the capacitor C1 is grounded;
the No. 6 pin of the voltage comparator U1B is used as an inverted terminal and is connected with one end of the resistor R14;
the other end of the resistor R14 forms the other input end of the third circuit and is connected with the output end of the second circuit;
and a pin 3 of the triode Q1 is connected with one end of the resistor R10, and the other end of the resistor R10 forms the output end of the third circuit.
8. The fan speed control method according to claim 1, wherein the receiving of the third signal and the controlling of the fan speed according to the distribution of the level state of the third signal are implemented based on a fourth circuit;
the fourth circuit includes: the circuit comprises a photoelectric coupler U2, a resistor R12, a bidirectional thyristor Q2, a resistor R15, a resistor R18, a resistor R13 and a capacitor C3;
a pin No. 1 of the photoelectric coupler U2 is connected with one end of the resistor R12 to form an input end of the fourth circuit;
the other end of the resistor R12 and a No. 2 pin of the photoelectric coupler U2 are grounded;
the No. 6 pin of the photoelectric coupler U2 is simultaneously connected with the anode of a first power supply, the No. 2 pin of the bidirectional thyristor Q2 and one end of the resistor R13;
the No. 4 pin of the photoelectric coupler U2 is connected with one end of the resistor R15;
the other end of the resistor R15 is simultaneously connected with the No. 3 pin of the bidirectional thyristor Q2 and one end of the resistor R18;
the other end of the resistor R18 is simultaneously connected with the pin No. 1 of the bidirectional thyristor Q2 and one end of the capacitor C3 to form the output end of the fourth circuit;
the other end of the capacitor C3 is connected with the other end of the resistor R13.
9. The fan speed regulation method of claim 6, wherein the voltage phase of the first signal is the same as the voltage phase of the pulse width modulation signal;
for any moment, if the amplitude comparison result shows that the amplitude of the first signal is higher than that of the second signal, the third signal is at a high level;
and if the amplitude comparison result shows that the amplitude of the first signal is not higher than the amplitude of the second signal, the third signal is at a low level.
10. A fan speed control system, characterized by, includes:
a receiving unit for receiving a third signal;
the control unit is used for controlling the rotating speed of the fan according to the distribution of the level state of the third signal;
the third signal is determined based on a comparison of the magnitudes of the first and second signals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111064526.2A CN113864217B (en) | 2021-09-10 | Fan speed regulation method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111064526.2A CN113864217B (en) | 2021-09-10 | Fan speed regulation method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113864217A true CN113864217A (en) | 2021-12-31 |
| CN113864217B CN113864217B (en) | 2024-07-30 |
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