Fan rotating speed control circuit and railway signal power supply module

Abstract

The invention discloses a fan rotating speed control circuit. The fan rotating speed control circuit comprises a fan FAN1; the positive electrode of the FAN1 is connected with one end of the fuse F1; the negative electrode of the FAN1 is connected with the drain electrode of the field effect transistor Q2 and the positive electrode of the diode D1; the source electrode of the Q2 is respectively connected with one end of a resistor R4, the collector electrode of a triode Q4, the emitter electrode of a triode Q3 and one end of an R5; the other end of the R4 is connected with the grid electrode of the Q2 and one end of a resistor R3; the other end of the R3 is connected with the emitter of the triode Q1 and the emitter of the triode Q4; the base electrode of Q4 is connected with the base electrode of Q1, the collector electrode of Q3, one end of R1 and the collector electrode of Q1; the base electrode of Q3 is connected with the other end of R5 and one end of R2; the other end of the R2 is connected with the output end of the single-chip microcomputer output current state detection. The other end of F1 is connected with one end of an inductor L1; and the other end of the L1 is respectively connected with the cathode of the D1, the other end of the R1 and a power supply VCC. The rotating speed of the fan can be safely and reliably controlled, and great practical significance is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of railway signal power supply system and fan control, and in particular to a fan speed control circuit and a railway signal power supply module. Background Art

[0002] Rail transit is an important form of transportation. The railway signal power supply system is responsible for providing various AC and DC power supplies for the entire station signal equipment. In the railway signal power supply system, the power module is a key device that converts the external power grid into the power required by the load.

[0003] With the rapid development of my country's rail transit, there are more and more electrical equipment, but the station area has not increased. The railway signal power supply system is required to develop in the direction of miniaturization and lightweight, which in turn requires the power density of the power modules used to be continuously improved. The power module is a power-consuming product, which will generate losses during operation. This loss will be dissipated in the form of heat. The accumulation of heat will affect the operation of electronic equipment. In order to ensure the normal operation of the power module, a fan needs to be installed inside the power module to dissipate the heat generated inside the power module in a timely manner.

[0004] Since the railway signal power supply system requires each output power supply to be isolated, the power module needs to be made into an isolated power supply system, that is, the input power supply and the output controller do not share a common ground. To ensure the safety and stability of the fan, the power module needs to control the fan speed. When the load size is different, the fan speed needs to be changed. Therefore, the fan speed control circuit of the railway signal power module needs to be able to control according to the output current.

[0005] However, there is currently no circuit that can meet the above requirements. Summary of the invention

[0006] The purpose of the present invention is to provide a fan speed control circuit and a railway signal power supply module in view of the technical defects in the prior art.

[0007] To this end, the present invention provides a fan speed control circuit, which includes a fan FAN1, transistors Q1, Q3 and Q4, a field effect transistor Q2, an inductor L1, a fuse F1, a diode D1 and resistors R1 to R5;

[0008] The positive pole of fan FAN1 is connected to one end of fuse F1;

[0009] The cathode of the fan FAN1 is connected to the drain of the field effect transistor Q2 and the anode of the diode D1 respectively;

[0010] The source of the field effect transistor Q2 is respectively connected to one end of the resistor R4, the collector of the transistor Q4, the emitter of the transistor Q3 and one end of the resistor R5;

[0011] The other end of the resistor R4 is connected to the gate of the field effect transistor Q2 and one end of the resistor R3 respectively;

[0012] The other end of the resistor R3 is connected to the emitter of the transistor Q1 and the emitter of the transistor Q4 respectively;

[0013] The base of transistor Q4 is respectively connected to the base of transistor Q1, the collector of transistor Q3, one end of resistor R1 and the collector of transistor Q1;

[0014] The base of transistor Q3 is connected to the other end of resistor R5 and one end of resistor R2;

[0015] The other end of the resistor R2 is connected to the output current state detection output end of the single chip microcomputer;

[0016] The other end of the fuse F1 is connected to one end of the inductor L1;

[0017] The other end of the inductor L1 is connected to the cathode of the diode D1, the other end of the resistor R1 and the power source VCC respectively.

[0018] In addition, the present invention also provides a railway signal power supply module, in which a fan is installed;

[0019] The fan has the fan speed control circuit as described above.

[0020] It can be seen from the technical solution provided by the present invention that, compared with the prior art, the present invention provides a fan speed control circuit and a railway signal power supply module, which are scientifically designed and can safely and reliably control the speed of the fan, and have great practical significance.

[0021] The railway signal power supply module of the present invention, when applied to a railway signal power supply system, can meet the condition of controlling the fan speed according to the load size, can safely and reliably control the power supply of the fan matched with the railway signal power supply module, and has high safety.

[0022] After inspection, it is found that the circuit provided by the present invention is a finely controlled and reliable circuit, which can be reliably applied to railway signal power supply module equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a fan speed control circuit provided by the present invention;

[0024] In the figure, FAN1-fan; Q1-transistor; Q3-transistor; Q4-transistor;

[0025] Q2-field effect tube;

[0026] R1-resistance; R2-resistance; R3-resistance; R4-resistance; R5-resistance;

[0027] C1-capacitor; C2-capacitor;

[0028] L1-inductor; F1-fuse; D1-diode. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] See also Figure 1 , the present invention provides a fan speed control circuit, comprising: a fan FAN1, transistors Q1, Q3 and Q4, a field effect transistor Q2, an inductor L1, a fuse F1, a diode D1 and resistors R1 to R5;

[0033] The positive pole of fan FAN1 is connected to one end of fuse F1;

[0034] The cathode of the fan FAN1 is connected to the drain of the field effect transistor Q2 and the anode of the diode D1 respectively;

[0035] The source of the field effect transistor Q2 is respectively connected to one end of the resistor R4, the collector of the transistor Q4, the emitter of the transistor Q3 and one end of the resistor R5;

[0036] The other end of the resistor R4 is connected to the gate of the field effect transistor Q2 and one end of the resistor R3 respectively;

[0037] The other end of the resistor R3 is connected to the emitter of the transistor Q1 and the emitter of the transistor Q4 respectively;

[0038] The base of transistor Q4 is respectively connected to the base of transistor Q1, the collector of transistor Q3, one end of resistor R1 and the collector of transistor Q1;

[0039] The base of transistor Q3 is connected to the other end of resistor R5 and one end of resistor R2;

[0040] The other end of the resistor R2 is connected to the output current state detection output end (i.e., FAN_PWM end) of the single-chip microcomputer MCU;

[0041] The other end of the fuse F1 is connected to one end of the inductor L1;

[0042] The other end of the inductor L1 is connected to the cathode of the diode D1, the other end of the resistor R1 and the power source VCC respectively.

[0043] In the present invention, in a specific implementation, the fan speed control circuit further includes: a capacitor C1;

[0044] Capacitor C1 is connected in parallel with fan 1;

[0045] In specific implementation, one end of the capacitor C1 is connected to the fuse F1 and the inductor L1 respectively;

[0046] The other end of the capacitor C1 is connected to the anode of the diode D1, the cathode of the fan FAN1 and the drain of the field effect transistor Q2.

[0047] In a specific implementation, the capacitor C1 is an electrolytic capacitor.

[0048] In the present invention, in a specific implementation, the fan speed control circuit further includes: a capacitor C2;

[0049] One end of the capacitor C2 is respectively connected to the collector of the transistor Q1, the collector of the transistor Q3, one end of the resistor R1 and the collector of the transistor Q1;

[0050] The other end of the capacitor C2 is connected to the source of the field effect transistor Q2, one end of the resistor R4, the collector of the transistor Q4, the emitter of the transistor Q3 and one end of the resistor R5;

[0051] In the present invention, in a specific implementation, the power supply VCC is a 12V direct current power supply DC.

[0052] It should be noted that the power supply VCC is used to provide working power for the fan FAN1;

[0053] In the present invention, in a specific implementation, the fan FAN1 is an electrical device of the present invention, for example, an axial flow fan.

[0054] In the present invention, in a specific implementation, the negative electrode of the fan FAN1 is grounded through the fan ground terminal GND2;

[0055] The source of the field effect transistor Q2, the collector of the transistor Q4 and the emitter of the transistor Q3 are grounded through the power ground terminal GND1;

[0056] It should be noted that the fan ground terminal GND2 and the power ground terminal GND1 are different grounding points, that is, they do not share the same grounding point. This requirement can avoid mutual influence.

[0057] In specific implementation, the 12V DC power supply DC and GND1 can be provided by the auxiliary power supply of the original power module in the railway signal power supply system. Figure 1 Use directly in.

[0058] In the present invention, in a specific implementation, transistors Q1 and Q3 are both NPN transistors, and Q4 is a PNP transistor;

[0059] Field effect transistor Q2 is an N-channel enhancement type field effect transistor.

[0060] In the present invention, in a specific implementation, the resistor R2 is a current limiting resistor;

[0061] Resistors R2 and R5 are connected to form a voltage divider circuit.

[0062] In the present invention, in a specific implementation, the single-chip microcomputer MCU is used to detect the output terminal through the output current state, output a control level signal to the transistor Q3 (specifically: output a high level signal or a low level signal to the transistor Q3), and control the rotation speed of the fan FAN1.

[0063] In specific implementation, the single-chip microcomputer MCU is a chip that comes with the existing railway signal power supply module. The current detection terminal it has is connected to the current output terminal of the railway signal power supply module. When the output current of the existing railway signal power supply module located outside is within a preset first normal value range (for example, 0A), it outputs a low-level signal (specifically a PWM signal with a low duty cycle, such as a duty cycle of 0%) to the transistor Q3; otherwise (that is, not within the first normal data range), it outputs a high-level signal (specifically a PWM signal with a high duty cycle, such as a duty cycle of 100%) to the transistor Q3.

[0064] It should be noted that the output current state detection output terminal on the single-chip microcomputer MCU is used to, when the output current of the railway signal power module is in the first normal range, the PWM duty cycle is low, and when it is not in the first normal range (for example, 0A), the PWM duty cycle is high; it should be noted that the function of the output current state detection output terminal on the single-chip microcomputer MCU is the original function of the railway signal power module (for example, the MW-Z220 / 20 high-frequency AC power module produced by Tianjin Railway Signal Co., Ltd.) The original (i.e., built-in) single-chip microcomputer MCU itself is an existing function on the finished equipment and will not be repeated here.

[0065] In specific implementation, the single-chip microcomputer MCU can be specifically a STM32F103R8T6 single-chip microcomputer produced by STMicroelectronics Co., Ltd. In the present invention, the single-chip microcomputer MCU is used to detect the state of the output current of the railway signal power module and output the detected state information to the circuit of the present invention.

[0066] In specific implementation, when the output current of the railway signal power module is in the first normal range (0A), the output current state detection output terminal PWM on the single-chip microcomputer MCU, at this time the PWM duty cycle is low, the transistor Q3 is turned off, the transistor Q4 is also turned off, the gate of the field effect transistor Q2 loses the driving voltage, and the speed of the fan FAN1 slows down;

[0067] When the output current of the railway signal power module is in the second normal range (0A-20A), the PWM duty cycle is high, the NPN transistor Q3 is activated and turned on, and the current path connected to the ground is opened. When the transistor Q3 is turned on, the PNP transistor Q4 is reverse biased, causing the transistor Q4 to be turned on. The conduction of the transistor Q4 controls the gate voltage of the field effect transistor Q2, so that the field effect transistor Q2 can be turned on, and the speed of the fan FAN1 is accelerated.

[0068] In the present invention, the parameter design and function of each device in the circuit are described as follows:

[0069] 1. Inductor L1 is used to store energy and limit current changes. It can suppress the voltage spike caused by current changes during the switching process of the field effect tube, thereby protecting the components in the circuit.

[0070] In specific implementation, when the field effect tube is turned on, current passes through the inductor and the inductor is gradually charged; when the field effect tube is turned off, the inductor releases the stored energy, maintains the current flow, and reduces voltage fluctuations.

[0071] In a specific implementation, the inductor L1 is preferably 68 μH.

[0072] 2. Diode D1, the selected model is MUR160, which is a reverse protection diode that ensures that current can only flow in one direction to prevent reverse current from damaging the circuit.

[0073] In specific implementation, when the field effect tube is turned off, the energy in the inductor L1 is released, and the diode D1 is turned on, allowing current to pass, thereby preventing the current from flowing back into the field effect tube and other components.

[0074] 3. Capacitor C1 is an aluminum electrolytic capacitor with a model of 1000μF / 25V. It is used to smooth the power supply voltage and store electrical energy to cope with instantaneous changes in current demand.

[0075] In specific implementation, when the load changes, the current will change instantaneously. Capacitor C1 can store enough electrical energy to provide additional current to the circuit when the fan speed changes, ensuring power supply stability and avoiding excessive voltage fluctuations due to load changes.

[0076] 4. Capacitor C2, the selected model is 100nF, which is used to filter out high-frequency noise.

[0077] In specific implementation, capacitor C2 provides a low impedance channel in the high-frequency signal, filters out unnecessary high-frequency noise, and ensures stable operation of the field-effect transistor.

[0078] 5. Fuse F1, model A72-065, is used for overcurrent protection.

[0079] In specific implementation, when the current exceeds the set value, the fuse F1 blows, cutting off the circuit to prevent the circuit components from being damaged due to overcurrent.

[0080] 6. The resistor R2 is 2.7kΩ, which is used to limit the current and protect the transistors Q3 and Q4.

[0081] In a specific implementation, the resistor R2 is used to limit the base current flowing through the transistor (ie, the transistor Q3) to avoid overcurrent damaging the transistor.

[0082] 7. Resistor R5, the selected model is 4.7KΩ, which is a voltage divider resistor used to stabilize the PWM (Pulse Width Modulation) signal input.

[0083] In a specific implementation, the resistor R5 is used to reduce the voltage of the PWM signal to a range suitable for the operation of the transistors Q3 and Q4 to ensure their normal conduction.

[0084] 8. Transistor Q3, the selected model is SS8050, and the selected model of transistor Q4 is SS8550;

[0085] Transistors Q3 and Q4 are used to amplify the PWM signal and drive the field effect tube Q2 to perform high current switching. Through the switching operation of the combination of Q3 and Q4, the PWM signal can effectively control the state of the field effect tube Q2.

[0086] It should be noted that when the PWM signal provided by the output current state detection output terminal on the single-chip microcomputer MCU is of high duty cycle (i.e., high level), the NPN transistor Q3 is activated and turned on, and the current path connected to the ground is opened. While the transistor Q3 is turned on, the PNP transistor Q4 is reverse biased, causing the transistor Q4 to be turned on. The conduction of Q4 controls the gate voltage of the field effect transistor Q2, so that Q2 can be turned on; when the PWM signal is of low duty cycle (i.e., low level), the transistor Q3 is turned off, and the transistor Q4 is therefore also turned off, and the gate of the field effect transistor Q2 loses the driving voltage.

[0087] 8. Field effect transistor Q2, the selected model is IRF630NPBF. When the duty cycle of the PWM signal changes, the on-time of the field effect transistor Q2 also changes accordingly. The longer the on-time, the more electric energy the fan obtains and the faster the speed; the shorter the on-time, the slower the fan speed.

[0088] In specific implementation, the field effect transistor Q2 is the core switch element of the circuit. As a high-speed switch device, when its gate has sufficient voltage, the field effect transistor Q2 is turned on, and the current flows from VCC to the fan. The on and off of the field effect transistor Q2 directly controls the start and stop of the fan. The fan ground terminal GND2 is controlled by the field effect transistor Q2 to form a loop with the power supply 12V.

[0089] 9. The resistance value of resistor R1 can be 2KΩ; the resistance values ​​of resistors R3 and R4 can be 10KΩ.

[0090] In summary, the circuit of the present invention can control the speed of the fan according to the load conditions and the output current, and adopts PWM duty cycle for control, which has lower power consumption and higher efficiency, and can dissipate the heat generated inside the power module more effectively and timely, thereby reducing the failure rate of the fan.

[0091] Based on the above Figure 1 The fan speed control circuit provided by the present invention is shown, and the present invention also provides a railway signal power supply module, in which a fan is installed;

[0092] The fan has the fan speed control circuit as described above.

[0093] In the present invention, it should be noted that the railway signal power supply module is a mature module in the prior art, for example, it can be a MW-Z220 / 20 high-frequency AC power supply module produced by Tianjin Railway Signal Co., Ltd., which adopts a miniaturized structure and air-cooled heat dissipation.

[0094] In the present invention, the railway signal power supply system where the railway signal power supply module is located is a railway signal power supply system with mature prior art technology, for example, it can be the PKX1 type lightweight railway signal power supply panel produced by Tianjin Railway Signal Co., Ltd. The system (i.e., the power supply panel) is composed of miniaturized AC and DC power supply modules.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fan speed control circuit, characterized in that: It includes a fan FAN1, transistors Q1, Q3 and Q4, a field effect transistor Q2, an inductor L1, a fuse F1, a diode D1 and resistors R1 to R5; The positive pole of fan FAN1 is connected to one end of fuse F1; The cathode of the fan FAN1 is connected to the drain of the field effect transistor Q2 and the anode of the diode D1 respectively; The source of the field effect transistor Q2 is respectively connected to one end of the resistor R4, the collector of the transistor Q4, the emitter of the transistor Q3 and one end of the resistor R5; The other end of the resistor R4 is connected to the gate of the field effect transistor Q2 and one end of the resistor R3 respectively; The other end of the resistor R3 is connected to the emitter of the transistor Q1 and the emitter of the transistor Q4 respectively; The base of transistor Q4 is respectively connected to the base of transistor Q1, the collector of transistor Q3, one end of resistor R1 and the collector of transistor Q1; The base of transistor Q3 is connected to the other end of resistor R5 and one end of resistor R2; The other end of the resistor R2 is connected to the output current state detection output end of the single chip microcomputer; The other end of the fuse F1 is connected to one end of the inductor L1; The other end of the inductor L1 is connected to the cathode of the diode D1, the other end of the resistor R1 and the power source VCC respectively.

2. The fan speed control circuit according to claim 1, characterized in that: Also includes: Capacitor C1; Capacitor C1 is connected in parallel with fan 1.

3. The fan speed control circuit according to claim 2, characterized in that: One end of the capacitor C1 is connected to the fuse F1 and the inductor L1 respectively; The other end of the capacitor C1 is connected to the anode of the diode D1, the cathode of the fan FAN1 and the drain of the field effect transistor Q2.

4. The fan speed control circuit according to any one of claims 1 to 3, characterized in that: Also includes: Capacitor C2; One end of the capacitor C2 is respectively connected to the collector of the transistor Q1, the collector of the transistor Q3, one end of the resistor R1 and the collector of the transistor Q1; The other end of the capacitor C2 is connected to the source of the field effect transistor Q2, one end of the resistor R4, the collector of the transistor Q4, the emitter of the transistor Q3 and one end of the resistor R5.

5. The fan speed control circuit according to claim 2, characterized in that: Capacitor C1 is an electrolytic capacitor; The power supply VCC is a 12V direct current power supply DC, which is used to provide working power for the fan FAN1.

6. The fan speed control circuit according to claim 1, characterized in that: Fan FAN1 is an axial flow fan.

7. The fan speed control circuit according to claim 1, characterized in that: Transistors Q1 and Q3 are both NPN transistors, and Q4 is a PNP transistor; Field effect transistor Q2 is an N-channel enhancement type field effect transistor.

8. The fan speed control circuit according to claim 1, characterized in that: The negative pole of the fan FAN1 is grounded through the fan ground terminal GND2; The source of the field effect transistor Q2, the collector of the transistor Q4 and the emitter of the transistor Q3 are grounded through the power ground terminal GND1.

9. The fan speed control circuit according to claim 1, characterized in that: The single chip microcomputer is used to detect the output terminal through the output current state thereon, and output a high level signal or a low level signal to the transistor Q3.

10. A railway signal power supply module, characterized in that: A fan is installed therein; The fan has the fan speed control circuit according to any one of claims 1 to 9.

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