High-power high-reliability direct-current power supply for subway LED guide screen

Abstract

The utility model provides a high-power high-reliability direct-current power supply for a subway LED (light-emitting diode) guide screen, which relates to the technical field of direct-current power supplies and is characterized in that clutters in rectified output voltage are filtered by an input filter circuit, and input alternating current is converted into direct current by the rectifier filter circuit; a PFC circuit is added in a power supply circuit to improve the power factor of a load, a PWM controller circuit is used to improve the working efficiency, a power conversion circuit is used to convert the energy of the input current into the signal power required by the load, and an output rectification filter circuit is used to control the current output of the high-power high-reliability direct current power supply for the subway LED guide screen. The high-power high-reliability direct-current power supply for the subway LED guide screen provided by the utility model has the characteristics of good heat dissipation performance, high reliability, low reactive power loss and the like, and can well adapt to a severe operating environment in the subway station LED guide screen.

Description

Technical Field

[0001] The utility model relates to the technical field of direct current power supplies, in particular to a high-power and high-reliability direct current power supply for a subway LED guide screen. Background Art

[0002] The subway station LED guide screen is powered by a built-in power module. The power module rectifies and steps down the input AC power (AC220V) into a low-voltage DC power supply (DC5V), providing working power for the LED dot matrix module and its ancillary equipment in the guide screen.

[0003] Currently, the power supply for subway station LED signage screens generally uses a universal power supply module. Because the space inside a subway station LED signage screen is small, airtight, and lacking ventilation, and the current required to drive the screen is high, the power supply generates a lot of heat. Universal power supplies are designed for general industrial applications and cannot fully adapt to the harsh, confined environment of subway station LED signage screens. Furthermore, the power supply's heat dissipation performance and component reliability are poor, resulting in a generally high failure rate. Utility Model Content

[0004] The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, which is used to solve the above-mentioned problems existing in the prior art.

[0005] The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, comprising an input filter circuit, a rectifier filter circuit, a PWM controller circuit, a PFC circuit, a power conversion circuit, and an output rectifier filter circuit;

[0006] The input end of the input filter circuit is connected to the output end of the external AC power supply, and the output end is connected to the input end of the rectifier filter circuit, which is used to filter out clutter in the input voltage;

[0007] The output end of the rectifier and filter circuit is connected to the input end of the PWM controller circuit, and is used to convert the input alternating current into direct current;

[0008] The output end of the PWM controller circuit is connected to the input end of the power conversion circuit to control the level of the output voltage;

[0009] The input end of the PFC circuit is connected to the output end of the LED internal power module, and the output end is connected to the input end of the power conversion circuit, so as to improve the power factor of the load;

[0010] The input end of the power conversion circuit is connected to the output end of the PWM controller circuit and the output end of the PFC circuit respectively, and the output end is connected to the input end of the output rectifier and filter circuit, and is used to convert the energy of the input current into the signal power required by the load;

[0011] The input end of the output rectifier filter circuit is connected to the output end of the power conversion circuit, and the output end is connected to the first end of the power management chip (U1), which is used to control the current output of the high-power and high-reliability DC power supply of the subway LED guide screen.

[0012] According to a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the input filter circuit includes a first capacitor (CY6), a second capacitor (CX2), a first resistor (F1), a second resistor (RT2), a third resistor (R1), a fourth resistor (R2), a first common-mode inductor (L3), and a second common-mode inductor (L2);

[0013] A first end of the first capacitor (CY6) is connected to the input end of the external AC power supply, and a second end is grounded;

[0014] The first end of the second capacitor (CX2) is connected to the first end of the third resistor (R1), and the second end is connected to the first end of the fourth resistor (R2);

[0015] The first end of the first resistor (F1) is connected to the first end of the first capacitor (CY6), and the second end is connected to the second end of the second capacitor (CX2);

[0016] A first end of the second resistor (RT2) is connected to the input end of the external AC power supply, and a second end is connected to the first end of the second capacitor (CX2);

[0017] A first end of the third resistor (R1) is connected to the input end of the first common-mode inductor (L3), and a second end is connected to the second end of the fourth resistor (R2);

[0018] The first end of the fourth resistor (R2) is connected to the input end of the first common-mode inductor (L3);

[0019] The output end of the first common-mode inductor (L3) is connected to the input end of the second common-mode inductor (L2);

[0020] The output end of the second common-mode inductor (L2) is connected to the input end of the rectifier and filter circuit.

[0021] According to a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the rectifier and filter circuit includes a bridge rectifier diode, a third capacitor (C5), a fourth capacitor (C2) and a fifth capacitor (CY1);

[0022] The input end of the bridge rectifier diode is connected to the output end of the rectifier filter circuit, the positive terminal of the output is connected to the first end of the third capacitor (C5), and the negative terminal of the output is connected to the second end of the third capacitor (C5);

[0023] A first end of the fourth capacitor (C2) is connected to a first end of the fifth capacitor (CY1), and a second end is grounded;

[0024] A first end of the fifth capacitor (CY1) is connected to the input end of the PWM controller circuit, and a second end is grounded.

[0025] According to a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the PWM controller circuit includes a fifth resistor (R61), a first transistor (Q10), a second transistor (Q11), a sixth capacitor (C27) and an isolation transformer (T2);

[0026] The first end of the fifth resistor (R61) is connected to the base of the first transistor (Q10), and the second end is connected to the input end of the rectifier filter circuit;

[0027] The base of the first transistor (Q10) is connected to the base of the second transistor (Q11), the emitter of the second transistor (Q11) is connected, and the collector is grounded;

[0028] The collector of the second transistor (Q11) is connected to the input end of the power conversion circuit, and the emitter is connected to the first end of the sixth capacitor (C27);

[0029] A second end of the sixth capacitor (C27) is grounded;

[0030] The input end of the isolation transformer (T2) is connected to the second end of the sixth capacitor (C27), and the output end is connected to the input end of the power conversion circuit.

[0031] According to the utility model, a high-power and high-reliability DC power supply for a subway LED guide screen is provided. The PFC circuit includes a first MOS tube (Q1), a second MOS tube (Q12), a sixth resistor (R24), a seventh resistor (R25), an eighth resistor (R67), a ninth resistor (R68), and a tenth resistor (R32);

[0032] The gate of the first MOS transistor (Q1) is connected to the first end of the sixth resistor (R24), the source is connected to the first end of the seventh resistor (R25), and the drain is connected to the input end of the power conversion circuit;

[0033] The gate of the second MOS tube (Q12) is connected to the first end of the eighth resistor (R67), the source is connected to the second end of the eighth resistor (R67), and the drain is connected to the output end of the LED internal power module;

[0034] The second end of the sixth resistor (R24) is connected to the first end of the ninth resistor (R68);

[0035] The second end of the seventh resistor (R25) is connected to the first end of the sixth resistor (R24);

[0036] The first end of the eighth resistor (R67) is connected to the second end of the ninth resistor (R68);

[0037] The first end of the ninth resistor (R68) is connected to the first end of the tenth resistor (R32);

[0038] The first end of the tenth resistor (R32) is connected to the second end of the sixth resistor (R24), and the second end is connected to the output end of the LED internal power supply module.

[0039] According to the utility model, a high-power and high-reliability DC power supply for a subway LED guide screen is provided, wherein the power conversion circuit includes a third MOS tube (Q5), a fourth MOS tube (Q6), a high-frequency transformer (T1) and an eleventh resistor (R15);

[0040] The gate of the third MOS tube (Q5) is connected to the first end of the eleventh resistor (R15), the source is connected to the first end of the eleventh resistor (R15), and the drain is connected to the input end of the high-frequency transformer (T1);

[0041] The gate of the fourth MOS tube (Q6) is connected to the input end of the high-frequency transformer (T1), the source is connected to the drain of the third MOS tube (Q5), and the drain is connected to the output end of the LED internal power module;

[0042] The input end of the high-frequency transformer (T1) is connected to the drain of the third MOS transistor and the gate of the fourth MOS transistor (Q6), respectively, and the output end is connected to the input end of the output rectifier filter circuit;

[0043] The first end of the eleventh resistor (R15) is connected to the source of the third MOS transistor, and the second end is grounded.

[0044] According to the utility model, a high-power and high-reliability DC power supply for a subway LED guide screen is provided. The output rectifier filter circuit includes an inductor (L1), a fifth MOS transistor (Q3), a sixth MOS transistor (Q4), a seventh MOS transistor (Q2), a seventh capacitor (C3), an eighth capacitor (C12), a ninth capacitor (C8), a tenth capacitor (C9), and an eleventh capacitor (C6);

[0045] The first end of the inductor (L1) is connected to the output end of the LED internal power supply module, and the second end is connected to the first end of the seventh capacitor (C3);

[0046] The gate of the fifth MOS tube (Q3) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0047] The gate of the sixth MOS tube (Q4) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0048] The gate of the seventh MOS tube (Q2) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0049] The first end of the seventh capacitor (C3) is connected to the second end of the inductor (L1), and the second end is grounded;

[0050] A first end of the eighth capacitor (C12) is connected to a first end of the seventh capacitor (C3), and a second end is grounded;

[0051] A first end of the ninth capacitor (C8) is connected to a first end of the eighth capacitor (C12), and a second end is grounded;

[0052] The first end of the tenth capacitor (C9) is connected to the first end of the ninth capacitor (C8), and the second end is grounded;

[0053] The first end of the eleventh capacitor (C6) is connected to the first end of the power management chip (U1), and the second end is grounded.

[0054] According to the high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the power management chip (U1) is an eight-pin chip.

[0055] According to a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the first resistor (F1) includes any one of a fast fuse, a slow fuse, a polysilicon fuse and a smart fuse.

[0056] According to a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model, the second resistor (RT2) includes any one of a metal oxide varistor and a varistor ceramic resistor.

[0057] The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen. The power supply filters out the noise in the rectifier output voltage through an input filter circuit, converts the input AC power into DC power through the rectifier filter circuit, and then adds a PFC circuit in the power supply circuit to improve the power factor of the load, reduce reactive loss, and reduce the self-heating of the power supply. The PWM controller circuit is used to improve the working efficiency, and the power conversion circuit is used to convert the energy of the input current into the signal power required by the load. The high-power and high-reliability DC power supply for the subway LED guide screen has the characteristics of good heat dissipation performance, high reliability, low reactive loss, etc., and can well adapt to the harsh operating environment of the LED guide screen in the subway station. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0059] Figure 1 This is a schematic diagram of a high-power and high-reliability DC power supply circuit for a subway LED guide screen provided by the utility model.

[0060] Figure 2 This is a schematic diagram of the power management chip provided by the utility model.

[0061] Figure 3 This is a schematic diagram of an input filter circuit provided by the utility model.

[0062] Figure 4 This is a schematic diagram of a rectifier and filter circuit provided by the utility model.

[0063] Figure 5 This is a schematic diagram of a PWM controller circuit provided by the utility model.

[0064] Figure 6 This is a schematic diagram of a PFC circuit provided by the utility model.

[0065] Figure 7 This is a schematic diagram of a power conversion circuit provided by the utility model.

[0066] Figure 8 This is a schematic diagram of an output rectifier and filter circuit provided by the utility model.

[0067] Figure 9 This is a layout diagram of components of a circuit board provided by the utility model.

[0068] Figure 10 This is a design drawing of a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model.

[0069] Figure 11 It is an assembly drawing of the radiator and power supply provided by the utility model.

[0070] Figure 12 This is a schematic diagram of the installation hole of the power module in the guide screen provided by the present invention.

[0071] Figure 13 This is a schematic diagram of calculating the safe distance between a high-power and high-reliability DC power supply for a subway LED guide screen and the front and rear guide screens provided by the utility model.

[0072] Figure 14 This is a schematic diagram of temperature rise estimation of a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model. DETAILED DESCRIPTION

[0073] Subway station LED signage is installed on station platforms to provide passengers with onboard guidance. It's primarily composed of multiple LED modules, which emit red, green, and blue light through an LED (light-emitting diode) matrix, creating the desired text and images.

[0074] The subway station LED guide screen is powered by a built-in power module. The power module rectifies and steps down the input AC power (AC220V) into a low-voltage DC power supply (DC5V), providing working power for the LED dot matrix module and its ancillary equipment in the guide screen.

[0075] The LED modules in subway station LED signage are composed of a 32x32 matrix of 1024 dots, each of which integrates three red, green, and blue LEDs. Because each power supply module needs to power multiple LED modules (driving numerous LED beads), power supplies for subway station LED signage typically feature low voltage (DC5V) and high output current (≥60A).

[0076] Currently, subway station LED guide screens generally use universal power modules. These modules are designed for general industrial applications and do not require high heat dissipation performance or reliability. For power modules rated above 30A, they require forced air cooling with built-in cooling fans.

[0077] Because the space inside the subway station LED guide screen is small, closed and not ventilated, and the current driving the LED guide screen is very large, the power supply generates a lot of heat. The universal power supply is designed for general industrial applications and cannot fully adapt to the harsh environment of the small and closed space inside the subway station LED guide screen. In addition, the power supply's heat dissipation performance and component reliability are poor, so the failure rate is generally high.

[0078] This utility model is a special power supply designed for the LED guide screen in subway stations. The power supply has the characteristics of good heat dissipation performance, high reliability, low reactive power loss, wide voltage input, and short startup time. It can adapt well to the harsh operating environment of the LED guide screen in subway stations.

[0079] To make the purpose, technical solutions, and advantages of the present invention more clear, the following will be combined with the accompanying drawings to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. 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.

[0080] The following combination Figures 1 to 14 The utility model describes a high-power and high-reliability DC power supply for a subway LED guide screen.

[0081] This utility model considers improving the working efficiency of the power supply from the circuit design perspective, adding a power factor correction (PFC) circuit, reducing reactive power loss, reducing the power supply's own heating, and reducing pollution to the public power grid; using phase-shifted full-bridge technology to improve efficiency by more than 85%; the PCBA layout considers the centralized arrangement of high-power devices at the bottom, and isolates the control circuit from the main circuit to reduce EMC and EMI interference problems; the main circuit consists of an input filter circuit, a rectifier filter circuit, a power conversion circuit, a pulse width modulation (PWM) controller circuit, a PFC circuit, an output rectifier filter circuit, and a surge protection circuit.

[0082] Figure 1 This is a schematic diagram of a high-power and high-reliability DC power supply circuit for a subway LED guide screen provided by this utility model. Figure 1 The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, which at least includes: an input filter circuit, a rectifier filter circuit, a PWM controller circuit, a PFC circuit, a power conversion circuit, and an output rectifier filter circuit.

[0083] The input end of the input filter circuit is connected to the output end of the external AC power supply, and the output end is connected to the input end of the rectifier filter circuit, which is used to filter out clutter in the input voltage;

[0084] The output end of the rectifier and filter circuit is connected to the input end of the PWM controller circuit, and is used to convert the input alternating current into direct current;

[0085] The output end of the PWM controller circuit is connected to the input end of the power conversion circuit to control the level of the output voltage;

[0086] The input end of the PFC circuit is connected to the output end of the LED internal power module, and the output end is connected to the input end of the power conversion circuit, so as to improve the power factor of the load;

[0087] The input end of the power conversion circuit is connected to the output end of the PWM controller circuit and the output end of the PFC circuit respectively, and the output end is connected to the input end of the output rectifier and filter circuit, and is used to convert the energy of the input current into the signal power required by the load;

[0088] The input end of the output rectifier filter circuit is connected to the output end of the power conversion circuit, and the output end is connected to the first end of the power management chip (U1), which is used to control the current output of the high-power and high-reliability DC power supply of the subway LED guide screen.

[0089] Specifically, the utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, which at least includes:

[0090] Input filter circuit, rectifier filter circuit, PWM controller circuit, PFC circuit, power conversion circuit and output rectifier filter circuit.

[0091] The input end of the input filter circuit is connected to the output end of the external AC power supply, and the output end is connected to the input end of the rectifier filter circuit to filter out the clutter in the input voltage;

[0092] The output end of the rectifier and filter circuit is connected to the input end of the PWM controller circuit to convert the input AC power into DC power;

[0093] The output end of the PWM controller circuit is connected to the input end of the power conversion circuit to control the level of the output voltage;

[0094] The input end of the PFC circuit is connected to the output end of the LED internal power module, and the output end is connected to the input end of the power conversion circuit to improve the power factor of the load;

[0095] The input end of the power conversion circuit is connected to the output end of the PWM controller circuit and the output end of the PFC circuit respectively, and the output end is connected to the input end of the output rectifier and filter circuit, and is used to convert the energy of the input current into the signal power required by the load;

[0096] The input end of the output rectifier filter circuit is connected to the output end of the power conversion circuit, and the output end is connected to the first end of the power management chip (U1), which is used to control the current output of the high-power and high-reliability DC power supply of the subway LED guide screen.

[0097] The embodiment of the present utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen. The input filter circuit filters out the noise in the rectifier output voltage, and converts the input AC power into DC power through the rectifier filter circuit. Then, a PFC circuit is added to the power supply circuit to improve the power factor of the load, reduce reactive loss, and reduce the self-heating of the power supply. A PWM controller circuit is used to improve work efficiency, and a power conversion circuit is used to convert the energy of the input current into the signal power required by the load. Therefore, the high-power and high-reliability DC power supply for the subway LED guide screen has the characteristics of good heat dissipation performance, high reliability, low reactive loss, wide voltage input, short startup time, etc., and can well adapt to the harsh operating environment of the LED guide screen in the subway station.

[0098] Optionally, the power management chip (U1) is an eight-pin chip.

[0099] Specifically, Figure 2 This is a schematic diagram of the power management chip provided by the utility model, such as Figure 2 The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen. The power management chip (U1) used is an eight-pin chip, including eight pins, which is a type of integrated circuit used to manage and control power in electronic equipment. The first end of the power management chip (U1) refers to Figure 2 Pin 7 in the second terminal refers to Figure 2 Pin 3 in the .

[0100] Optionally, the input filter circuit includes a first capacitor (CY6), a second capacitor (CX2), a first resistor (F1), a second resistor (RT2), a third resistor (R1), a fourth resistor (R2), a first common-mode inductor (L3), and a second common-mode inductor (L2);

[0101] A first end of the first capacitor (CY6) is connected to the input end of the external AC power supply, and a second end is grounded;

[0102] The first end of the second capacitor (CX2) is connected to the first end of the third resistor (R1), and the second end is connected to the first end of the fourth resistor (R2);

[0103] The first end of the first resistor (F1) is connected to the first end of the first capacitor (CY6), and the second end is connected to the second end of the second capacitor (CX2);

[0104] A first end of the second resistor (RT2) is connected to the input end of the external AC power supply, and a second end is connected to the first end of the second capacitor (CX2);

[0105] A first end of the third resistor (R1) is connected to the input end of the first common-mode inductor (L3), and a second end is connected to the second end of the fourth resistor (R2);

[0106] The first end of the fourth resistor (R2) is connected to the input end of the first common-mode inductor (L3);

[0107] The output end of the first common-mode inductor (L3) is connected to the input end of the second common-mode inductor (L2);

[0108] The output end of the second common-mode inductor (L2) is connected to the input end of the rectifier and filter circuit.

[0109] Specifically, Figure 3 This is a schematic diagram of the input filter circuit provided by the utility model, such as Figure 3 shown.

[0110] The input filter circuit includes a first capacitor (CY6), a second capacitor (CX2), a first resistor (F1), a second resistor (RT2), a third resistor (R1), a fourth resistor (R2), a first common-mode inductor (L3), and a second common-mode inductor (L2);

[0111] A first end of the first capacitor (CY6) is connected to the input end of the external AC power supply, and a second end thereof is grounded;

[0112] A first end of the second capacitor (CX2) is connected to a first end of the third resistor (R1), and a second end is connected to a first end of the fourth resistor (R2);

[0113] A first end of the first resistor (F1) is connected to a first end of the first capacitor (CY6), and a second end of the first resistor (F1) is connected to a second end of the second capacitor (CX2);

[0114] A first end of a second resistor (RT2) is connected to an input end of an external AC power supply, and a second end is connected to a first end of a second capacitor (CX2);

[0115] A first end of the third resistor (R1) is connected to the input end of the first common-mode inductor (L3), and a second end is connected to the second end of the fourth resistor (R2);

[0116] A first end of the fourth resistor (R2) is connected to an input end of the first common-mode inductor (L3);

[0117] The output end of the first common-mode inductor (L3) is connected to the input end of the second common-mode inductor (L2);

[0118] The output end of the second common-mode inductor (L2) is connected to the input end of the rectifier and filter circuit.

[0119] Furthermore, the input filter circuit also includes a surge protection circuit, which is composed of a second capacitor (CX2), a third resistor (R1) and a fourth resistor (R2).

[0120] Surge protection circuits protect electronic equipment (such as power supply equipment) from overvoltage damage by limiting, absorbing or decomposing overvoltage surges on the power supply line, while input filter circuits can filter out noise in the rectified output voltage and suppress interference signals input from the AC power grid.

[0121] Specifically, the mains voltage passes through an input filter circuit consisting of an input fuse (i.e., the second resistor RT2), a thermistor (i.e., the first resistor F1), a resistor-capacitor filter (i.e., a surge protection circuit), and a first common-mode inductor element L3. The resistor-capacitor filter and the common-mode inductor filter remove clutter from the input voltage, resulting in a good sine wave.

[0122] Optionally, the first resistor (F1) includes any one of a fast fuse, a slow fuse, a polysilicon fuse, and a smart fuse.

[0123] Specifically, the first resistor (F1) is a fuse resistor, including any one of a fast fuse, a slow fuse, a polysilicon fuse, and a smart fuse. Under normal circumstances, the fuse resistor has the function of an ordinary resistor. However, once a circuit fault occurs and its rated power is exceeded, it will disconnect the circuit within a specified time, thereby achieving the purpose of protecting other components.

[0124] Optionally, the second resistor (RT2) includes any one of a metal oxide varistor and a varistor ceramic resistor.

[0125] Specifically, the second resistor (RT2) is a varistor, including any one of a metal oxide varistor and a varistor ceramic resistor, and is mainly used to clamp the voltage when the circuit is subjected to overvoltage, and absorb excess current to protect sensitive devices.

[0126] Optionally, the rectification and filtering circuit includes a bridge rectifier diode, a third capacitor (C5), a fourth capacitor (C2) and a fifth capacitor (CY1);

[0127] The input end of the bridge rectifier diode is connected to the output end of the rectifier filter circuit, the positive end of the output is connected to the first end of the third capacitor (C5), and the negative end of the output is connected to the second end of the third capacitor (C5);

[0128] A first end of the fourth capacitor (C2) is connected to a first end of the fifth capacitor (CY1), and a second end is grounded;

[0129] A first end of the fifth capacitor (CY1) is connected to the input end of the PWM controller circuit, and a second end is grounded.

[0130] Specifically, Figure 4 This is a schematic diagram of the rectifier and filter circuit provided by the utility model. Figure 4 shown.

[0131] The rectifier and filter circuit includes a bridge rectifier diode, a third capacitor (C5), a fourth capacitor (C2), and a fifth capacitor (CY1);

[0132] The input end of the bridge rectifier diode is connected to the output end of the rectifier filter circuit, the positive terminal of the output is connected to the first end of the third capacitor (C5), and the negative terminal of the output is connected to the second end of the third capacitor (C5);

[0133] A first end of the fourth capacitor (C2) is connected to a first end of the fifth capacitor (CY1), and a second end thereof is grounded;

[0134] A first end of the fifth capacitor (CY1) is connected to the input end of the PWM controller circuit, and a second end thereof is grounded.

[0135] Specifically, the voltage output by the input filter circuit first passes through a bridge rectifier diode to rectify the AC into DC, and then passes through the ceramic filter capacitor (i.e., the third capacitor C5 and the fourth capacitor C2) and the electrolytic capacitor (i.e., the fifth capacitor CY1) for charging and discharging, thereby filtering out the pulsating components in the DC and converting it into a smooth DC output.

[0136] Optionally, the PWM controller circuit includes a fifth resistor (R61), a first transistor (Q10), a second transistor (Q11), a sixth capacitor (C27) and an isolation transformer (T2);

[0137] The first end of the fifth resistor (R61) is connected to the base of the first transistor (Q10), and the second end is connected to the input end of the rectifier filter circuit;

[0138] The base of the first transistor (Q10) is connected to the base of the second transistor (Q11), the emitter of the second transistor (Q11) is connected, and the collector is grounded;

[0139] The collector of the second transistor (Q11) is connected to the input end of the power conversion circuit, and the emitter is connected to the first end of the sixth capacitor (C27);

[0140] A second end of the sixth capacitor (C27) is grounded;

[0141] The input end of the isolation transformer (T2) is connected to the second end of the sixth capacitor (C27), and the output end is connected to the input end of the power conversion circuit.

[0142] Specifically, Figure 5 This is a schematic diagram of the PWM controller circuit provided by the utility model, such as Figure 5 shown.

[0143] The PWM controller circuit includes a fifth resistor (R61), a first transistor (Q10), a second transistor (Q11), a sixth capacitor (C27) and an isolation transformer (T2);

[0144] A first end of a fifth resistor (R61) is connected to the base of the first transistor (Q10), and a second end is connected to the second end of the first power management chip (U6);

[0145] The base of the first transistor (Q10) is connected to the base of the second transistor (Q11), the emitter of the second transistor (Q11) is connected, and the collector is grounded;

[0146] The collector of the second transistor (Q11) is connected to the input end of the power conversion circuit, and the emitter is connected to the first end of the sixth capacitor (C27);

[0147] A second terminal of the sixth capacitor (C27) is grounded;

[0148] The input end of the isolation transformer (T2) is connected to the second end of the sixth capacitor (C27), and the output end is connected to the input end of the power conversion circuit.

[0149] Specifically, an integrated circuit (i.e., power management chip U1) generates a pulse signal, which is amplified by the first and second MOS transistors Q1 and Q2. This signal then forms a loop with the primary coil of the isolation transformer T2. The secondary coil of the isolation transformer T2 then forms a loop with the high-voltage switching transistor D2, forming a PWM controller circuit. The PWM controller adjusts the output voltage by controlling the pulse duty cycle.

[0150] Optionally, the PFC circuit includes a first MOS transistor (Q1), a second MOS transistor (Q12), a sixth resistor (R24), a seventh resistor (R25), an eighth resistor (R67), a ninth resistor (R68), and a tenth resistor (R32);

[0151] The gate of the first MOS transistor (Q1) is connected to the first end of the sixth resistor (R24), the source is connected to the first end of the seventh resistor (R25), and the drain is connected to the input end of the power conversion circuit;

[0152] The gate of the second MOS tube (Q12) is connected to the first end of the eighth resistor (R67), the source is connected to the second end of the eighth resistor (R67), and the drain is connected to the output end of the LED internal power module;

[0153] The second end of the sixth resistor (R24) is connected to the first end of the ninth resistor (R68);

[0154] The second end of the seventh resistor (R25) is connected to the first end of the sixth resistor (R24);

[0155] The first end of the eighth resistor (R67) is connected to the second end of the ninth resistor (R68);

[0156] The first end of the ninth resistor (R68) is connected to the first end of the tenth resistor (R32);

[0157] The first end of the tenth resistor (R32) is connected to the second end of the sixth resistor (R24), and the second end is connected to the output end of the LED internal power supply module.

[0158] Specifically, Figure 6 This is a schematic diagram of the PFC circuit provided by the utility model, such as Figure 6 shown.

[0159] The PFC circuit includes a first MOS transistor (Q1), a second MOS transistor (Q12), a sixth resistor (R24), a seventh resistor (R25), an eighth resistor (R67), a ninth resistor (R68), and a tenth resistor (R32);

[0160] The gate of the first MOS tube (Q1) is connected to the first end of the sixth resistor (R24), the source is connected to the first end of the seventh resistor (R25), and the drain is connected to the input end of the power conversion circuit;

[0161] The gate of the second MOS tube (Q12) is connected to the first end of the eighth resistor (R67), the source is connected to the second end of the eighth resistor (R67), and the drain is connected to the output end of the LED internal power module;

[0162] The second end of the sixth resistor (R24) is connected to the first end of the ninth resistor (R68);

[0163] The second end of the seventh resistor (R25) is connected to the first end of the sixth resistor (R24);

[0164] A first end of the eighth resistor (R67) is connected to a second end of the ninth resistor (R68);

[0165] A first end of a ninth resistor (R68) is connected to a first end of a tenth resistor (R32);

[0166] The first end of the tenth resistor (R32) is connected to the second end of the sixth resistor (R24), and the second end is connected to the output end of the LED internal power module.

[0167] Specifically, the PFC circuit adjusts the phase relationship between current and voltage to bring the power factor close to unity, thereby reducing reactive power waste. Current harmonics can cause grid voltage fluctuations and energy loss. The PFC circuit reduces harmonic currents, minimizing grid interference and improving system stability. Because the PFC circuit reduces reactive power consumption, it can also improve power supply efficiency.

[0168] Optionally, the power conversion circuit includes a third MOS transistor (Q5), a fourth MOS transistor (Q6), a high-frequency transformer (T1), and an eleventh resistor (R15);

[0169] The gate of the third MOS tube (Q5) is connected to the first end of the eleventh resistor (R15), the source is connected to the first end of the eleventh resistor (R15), and the drain is connected to the input end of the high-frequency transformer (T1);

[0170] The gate of the fourth MOS tube (Q6) is connected to the input end of the high-frequency transformer (T1), the source is connected to the drain of the third MOS tube (Q5), and the drain is connected to the output end of the LED internal power module;

[0171] The input end of the high-frequency transformer (T1) is connected to the drain of the third MOS transistor and the gate of the fourth MOS transistor (Q6), respectively, and the output end is connected to the input end of the output rectifier filter circuit;

[0172] The first end of the eleventh resistor (R15) is connected to the source of the third MOS transistor, and the second end is grounded.

[0173] Specifically, Figure 7 This is a schematic diagram of a power conversion circuit provided by the present invention. Figure 7 shown.

[0174] The power conversion circuit includes a third MOS tube (Q5), a fourth MOS tube (Q6), a high-frequency transformer (T1), and an eleventh resistor (R15);

[0175] The gate of the third MOS tube (Q5) is connected to the first end of the eleventh resistor (R15), the source is connected to the first end of the eleventh resistor (R15), and the drain is connected to the input end of the high-frequency transformer (T1);

[0176] The gate of the fourth MOS tube (Q6) is connected to the input end of the high-frequency transformer (T1), the source is connected to the drain of the third MOS tube (Q5), and the drain is connected to the output end of the LED internal power module;

[0177] The input end of the high-frequency transformer (T1) is connected to the drain of the third MOS tube and the gate of the fourth MOS tube (Q6), respectively, and the output end is connected to the input end of the output rectifier filter circuit;

[0178] A first end of the eleventh resistor (R15) is connected to the source of the third MOS transistor, and a second end is grounded.

[0179] Specifically, the input signal is stepped down by high-frequency transformer T1 and then fed into the half-bridge circuit. Based on the required output voltage, the PWM controller generates appropriate PWM signals to control the on / off states of the switches. The output voltage can be regulated by adjusting the duty cycle of the PWM signals. The two switches in the half-bridge circuit alternately switch on and off, resulting in a periodic switching of the output voltage between positive and negative polarity. The output signal is smoothed by a filter circuit to remove high-frequency noise introduced by the switching, resulting in a stable DC output voltage.

[0180] Optionally, the output rectifier filter circuit includes an inductor (L1), a fifth MOS transistor (Q3), a sixth MOS transistor (Q4), a seventh MOS transistor (Q2), a seventh capacitor (C3), an eighth capacitor (C12), a ninth capacitor (C8), a tenth capacitor (C9), and an eleventh capacitor (C6);

[0181] The first end of the inductor (L1) is connected to the output end of the LED internal power supply module, and the second end is connected to the first end of the seventh capacitor (C3);

[0182] The gate of the fifth MOS tube (Q3) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0183] The gate of the sixth MOS tube (Q4) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0184] The gate of the seventh MOS tube (Q2) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0185] The first end of the seventh capacitor (C3) is connected to the second end of the inductor (L1), and the second end is grounded;

[0186] A first end of the eighth capacitor (C12) is connected to a first end of the seventh capacitor (C3), and a second end is grounded;

[0187] A first end of the ninth capacitor (C8) is connected to a first end of the eighth capacitor (C12), and a second end is grounded;

[0188] The first end of the tenth capacitor (C9) is connected to the first end of the ninth capacitor (C8), and the second end is grounded;

[0189] The first end of the eleventh capacitor (C6) is connected to the first end of the power management chip (U1), and the second end is grounded.

[0190] Specifically, Figure 8 This is a schematic diagram of the output rectifier and filter circuit provided by the utility model. Figure 8 shown.

[0191] The output rectifier filter circuit includes an inductor (L1), a fifth MOS transistor (Q3), a sixth MOS transistor (Q4), a seventh MOS transistor (Q2), a seventh capacitor (C3), an eighth capacitor (C12), a ninth capacitor (C8), a tenth capacitor (C9), and an eleventh capacitor (C6);

[0192] The first end of the inductor (L1) is connected to the output end of the LED internal power supply module, and the second end is connected to the first end of the seventh capacitor (C3);

[0193] The gate of the fifth MOS tube (Q3) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0194] The gate of the sixth MOS tube (Q4) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0195] The gate of the seventh MOS tube (Q2) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module;

[0196] A first end of a seventh capacitor (C3) is connected to the second end of the inductor (L1), and the second end is grounded;

[0197] A first end of the eighth capacitor (C12) is connected to the first end of the seventh capacitor (C3), and a second end is grounded;

[0198] A first end of a ninth capacitor (C8) is connected to a first end of an eighth capacitor (C12), and a second end thereof is grounded;

[0199] A first end of the tenth capacitor (C9) is connected to the first end of the ninth capacitor (C8), and a second end thereof is grounded;

[0200] The first end of the eleventh capacitor (C6) is connected to the first end of the power management chip (U1), and the second end is grounded.

[0201] Specifically, the basic working principle of the output rectifier filter circuit is to use a filter circuit composed of reactive elements (such as capacitors and inductors) to filter out the pulsating components in the voltage to obtain a smooth DC voltage.

[0202] The embodiment of the present utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen. The input filter circuit filters out the noise in the rectifier output voltage, and converts the input AC power into DC power through the rectifier filter circuit. Then, a PFC circuit is added to the power supply circuit to improve the power factor of the load, reduce reactive loss, and reduce the self-heating of the power supply. A PWM controller circuit is used to improve work efficiency, and a power conversion circuit is used to convert the energy of the input current into the signal power required by the load. Therefore, the high-power and high-reliability DC power supply for the subway LED guide screen has the characteristics of good heat dissipation performance, high reliability, low reactive loss, wide voltage input, short startup time, etc., and can well adapt to the harsh operating environment of the LED guide screen in the subway station.

[0203] The embodiment of the present utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, which also includes the following design of appearance, structure and components.

[0204] Figure 9 This is the layout diagram of the circuit board components provided by the utility model, such as Figure 9 shown.

[0205] Among them, F1 is a thermistor, C2 / C6 / C7 / C8 / C9 / C10 / C12 / C14 / C17 / C18 are electrolytic capacitors, RT1 is a varistor, D1 / D3 / D3 / D18 are diodes, and JMP1 to JMP9 are jumper wires.

[0206] In terms of component selection, since the mean time between failures (MTBF) of a device depends on the reliability of each component of the device, the electronic components used in the embodiments of the present invention are all of reliable high-quality brands (for example, electrolytic capacitors use ruby capacitors with a temperature of 105°C); power devices use advanced material technology and have the advantages of small size and high efficiency (low heat generation); components such as diodes and transistors should consider leaving a design margin of 1.5 times; component selection uses wide-temperature devices (-25°C ~ 105°C) to ensure the operational reliability of each component.

[0207] Figure 10 The utility model provides a high-power and high-reliability DC power supply design for subway LED guide screens, such as Figure 10 shown.

[0208] In terms of appearance design, in order to adapt to the LED guide screen, the size of the power supply of this utility model should be basically the same as the original power supply size, and the size cannot be greater than 10mm. Therefore, considering various factors, the utility model provides a subway LED guide screen high-power and high-reliability DC power supply size design as follows: Figure 10 shown.

[0209] The power supply has dimensions of 217 mm (length) × 81.6 mm (width) × 31.5 mm (height). The AC input terminal arrangement is PE / L / L / N / N; the DC output terminal arrangement is V+ / V+ / V+ / V- / V- / V-.

[0210] In terms of heat dissipation design, the utility model provides a high-power and high-reliability DC power supply for the subway LED guide screen, which adopts a fanless aluminum alloy body for heat dissipation, focusing on improving the operating efficiency of the power supply (reducing reactive power loss and reducing self-heating). The utility model attaches the high-power device to the bottom of the casing through thermal conductive silicone grease, and conducts heat to the casing for heat dissipation; the module adopts an electronic potting glue potting process to improve the thermal conductivity, insulation performance and seismic resistance of the power supply.

[0211] Because the power supply in this utility model utilizes a fanless design and draws a lot of power, heat dissipation from the power module is crucial. To further improve heat dissipation efficiency, this utility model incorporates a dedicated heat sink for the power supply. This heat sink adheres tightly to the power supply housing using thermally conductive silicone grease. Large-area cooling fins are designed on the heat sink surface, rapidly transferring heat generated by the power supply to the surrounding air. This significantly improves heat dissipation efficiency and keeps the power supply temperature consistently low. This lower operating temperature also reduces the temperature of the electronic components within the power supply, significantly reducing the likelihood of power supply failures.

[0212] Figure 11 This is the assembly diagram of the radiator and power supply provided by the utility model, such as Figure 11 shown.

[0213] The radiator is made of aluminum alloy profiles, the radiator base plate thickness is 6mm, the heat sink fin design is 24 teeth, the tooth thickness is 1.15mm, the tooth pitch is 2.15mm, the tooth height is 21mm, and the radiator surface is anodized.

[0214] The heat sink is installed at the bottom of the power module. The fixing holes of the heat sink have a spacing of 178 mm x 67.5 mm. The heat sink and power module are assembled together using four M3 hexagon socket head cap bolts.

[0215] Thermal grease is applied between the heat sink and the power module to enhance heat conduction between the power module and the heat sink.

[0216] Figure 12 This is a schematic diagram of the installation hole of the power module in the guide screen provided by the utility model, such as Figure 12 shown.

[0217] The power supply and the LED guide screen need to match each other. The power supply module is fixed to the frame inside the LED guide screen by screws. In order to ensure the normal installation of the high-power and high-reliability DC power supply for the subway LED guide screen provided by the utility model, the installation hole of the power supply is completely consistent with the reserved hole of the guide screen.

[0218] Figure 13 This is a schematic diagram of calculating the safe distance between a high-power and high-reliability DC power supply for a subway LED guide screen and the front and rear guide screens provided by the utility model, as shown in the figure. Figure 13 shown.

[0219] After the power module is equipped with a heat sink, its thickness will increase compared to the original power supply. Through small factory measurements and CAD calculations, we ensure that the high-power and high-reliability DC power supply (including heat sink) provided by this utility model can be installed normally inside the LED guide screen, leaving a safe space.

[0220] Furthermore, the embodiment of the present invention also conducts a temperature test on a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention, and conducts an estimated analysis of the heat dissipation performance of the DC power supply. Figure 14 This is a schematic diagram of temperature rise estimation of a high-power and high-reliability DC power supply for a subway LED guide screen provided by the utility model. Figure 14 shown.

[0221] Figure 14 The comparison results of the heat dissipation efficiency of the power module are shown. The red curve is the temperature rise curve of the power module for general industrial applications, and the green curve is the temperature rise curve of a high-power and high-reliability DC power supply for a subway LED guide screen provided by this utility model. Figure 14As shown, under the same output power, the DC power supply provided by the present invention has a lower temperature and therefore a higher heat dissipation efficiency.

[0222] Furthermore, the embodiment of the present invention also conducted a load voltage drop test on a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention. Table 1 is a table of the load voltage drop test results of the new power supply provided by the embodiment of the present invention, as shown in Table 1. Among them, the new power supply is a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention.

[0223] Table 1 New power supply load voltage drop test results

[0224]

[0225] An electronic load was used to test the power module's output voltage drop at 0A, 30A, and 50A. The test showed that the power module's output voltage drop was ≤10%, meeting the requirements.

[0226] Furthermore, the embodiment of the present invention also conducted a room temperature load temperature rise test on a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention. Table 2 is a table of room temperature load temperature rise test results of the new power supply provided by the embodiment of the present invention, as shown in Table 2.

[0227] Table 2 New power supply normal temperature load temperature rise test results

[0228]

[0229] The power module was subjected to a temperature rise test at room temperature with an electronic load at loads of 30A, 40A, and 50A (each test lasting three hours). The maximum temperature of the power module housing was observed and recorded. The test showed that the power module maintained a body temperature of ≤85°C under load at room temperature, meeting the requirements.

[0230] Furthermore, the embodiment of the present invention also carried out a load test on a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention in a high-temperature and sealed environment without a heat sink. Table 3 is a load test result table of the new power supply provided by the embodiment of the present invention in a high-temperature and sealed environment without a heat sink, as shown in Table 3.

[0231] Table 3 Load test results of the new power supply without heat sink and in a high temperature closed environment

[0232]

[0233] Furthermore, the embodiment of the present invention also carried out a load test on a high-power and high-reliability DC power supply for a subway LED guide screen provided by the present invention in a high-temperature and sealed environment with a heat sink. Table 4 is a load test result table of the new power supply provided by the embodiment of the present invention in a high-temperature and sealed environment without a heat sink, as shown in Table 4.

[0234] Table 4 Load test results of the new power supply without heat sink in a high temperature and sealed environment

[0235]

[0236] After the power module was assembled with the heat sink, it was able to complete the load test normally in a high-temperature, enclosed environment (that is, at an ambient temperature of 70°C with no ventilation, the power supply carried a 20A load and operated stably without any problems). The test results are shown in Table 4.

[0237] Based on any of the above embodiments, the high-power, high-reliability DC power supply for subway LED guide screens provided by the present invention has excellent heat dissipation performance and low heat generation compared to the original power supply. Under the same operating conditions, the temperature rise of the high-power, high-reliability DC power supply for subway LED guide screens provided by the present invention is 5-20°C lower than that of the original power supply in the prior art.

[0238] Based on any of the above embodiments, to ensure the reliability of the high-power, high-reliability DC power supply for the subway LED guide screen provided by the present invention, the electronic components used in the high-power, high-reliability DC power supply for the subway LED guide screen provided by the present invention are all of reliable, high-quality brands. The power devices used are made of advanced materials, have advantages such as small size and high efficiency; the power devices all adopt wide-temperature devices and are selected with a margin of ≥1.5 times; by improving the reliability of the components, the reliability of the entire device is guaranteed to be improved.

[0239] Since the high-power and high-reliability DC power supply for the subway LED guide screen provided by the utility model has good heat dissipation performance and low heat generation, the operating temperature of the components is low, thereby having a long service life and a low failure rate.

[0240] The utility model provides a high-power and high-reliability DC power supply for a subway LED guide screen, which adopts body heat dissipation and has no cooling fan. Compared with the original power supply in the prior art (which adopts a cooling fan for heat dissipation, and the power supply will be damaged immediately if the fan is damaged), its reliability is greatly improved.

[0241] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0242] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0243] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-power and high-reliability DC power supply for subway LED guide screens, characterized in that: include: Input filter circuit, rectifier filter circuit, PWM controller circuit, PFC circuit, power conversion circuit and output rectifier filter circuit; The input end of the input filter circuit is connected to the output end of the external AC power supply, and the output end is connected to the input end of the rectifier filter circuit, which is used to filter out clutter in the input voltage; The output end of the rectifier and filter circuit is connected to the input end of the PWM controller circuit, and is used to convert the input alternating current into direct current; The output end of the PWM controller circuit is connected to the input end of the power conversion circuit to control the level of the output voltage; The input end of the PFC circuit is connected to the output end of the LED internal power module, and the output end is connected to the input end of the power conversion circuit, so as to improve the power factor of the load; The input end of the power conversion circuit is connected to the output end of the PWM controller circuit and the output end of the PFC circuit respectively, and the output end is connected to the input end of the output rectifier and filter circuit, and is used to convert the energy of the input current into the signal power required by the load; The input end of the output rectifier filter circuit is connected to the output end of the power conversion circuit, and the output end is connected to the first end of the power management chip (U1), which is used to control the current output of the high-power and high-reliability DC power supply of the subway LED guide screen.

2. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The input filter circuit includes a first capacitor (CY6), a second capacitor (CX2), a first resistor (F1), a second resistor (RT2), a third resistor (R1), a fourth resistor (R2), a first common-mode inductor (L3) and a second common-mode inductor (L2); A first end of the first capacitor (CY6) is connected to the input end of the external AC power supply, and a second end is grounded; The first end of the second capacitor (CX2) is connected to the first end of the third resistor (R1), and the second end is connected to the first end of the fourth resistor (R2); The first end of the first resistor (F1) is connected to the first end of the first capacitor (CY6), and the second end is connected to the second end of the second capacitor (CX2); A first end of the second resistor (RT2) is connected to the input end of the external AC power supply, and a second end is connected to the first end of the second capacitor (CX2); A first end of the third resistor (R1) is connected to the input end of the first common-mode inductor (L3), and a second end is connected to the second end of the fourth resistor (R2); The first end of the fourth resistor (R2) is connected to the input end of the first common-mode inductor (L3); The output end of the first common-mode inductor (L3) is connected to the input end of the second common-mode inductor (L2); The output end of the second common-mode inductor (L2) is connected to the input end of the rectifier and filter circuit.

3. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The rectification and filtering circuit includes a bridge rectifier diode, a third capacitor (C5), a fourth capacitor (C2) and a fifth capacitor (CY1); The input end of the bridge rectifier diode is connected to the output end of the rectifier filter circuit, the positive end of the output is connected to the first end of the third capacitor (C5), and the negative end of the output is connected to the second end of the third capacitor (C5); the first end of the fourth capacitor (C2) is connected to the first end of the fifth capacitor (CY1), and the second end is grounded; A first end of the fifth capacitor (CY1) is connected to the input end of the PWM controller circuit, and a second end is grounded.

4. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The PWM controller circuit includes a fifth resistor (R61), a first transistor (Q10), a second transistor (Q11), a sixth capacitor (C27) and an isolation transformer (T2); The first end of the fifth resistor (R61) is connected to the base of the first transistor (Q10), and the second end is connected to the input end of the rectifier filter circuit; The base of the first transistor (Q10) is connected to the base of the second transistor (Q11), the emitter of the second transistor (Q11) is connected, and the collector is grounded; The collector of the second transistor (Q11) is connected to the input end of the power conversion circuit, and the emitter is connected to the first end of the sixth capacitor (C27); A second end of the sixth capacitor (C27) is grounded; The input end of the isolation transformer (T2) is connected to the second end of the sixth capacitor (C27), and the output end is connected to the input end of the power conversion circuit.

5. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The PFC circuit comprises a first MOS transistor (Q1), a second MOS transistor (Q12), a sixth resistor (R24), a seventh resistor (R25), an eighth resistor (R67), a ninth resistor (R68) and a tenth resistor (R32); The gate of the first MOS tube (Q1) is connected to the first end of the sixth resistor (R24), the source is connected to the first end of the seventh resistor (R25), and the drain is connected to the input end of the power conversion circuit; The gate of the second MOS tube (Q12) is connected to the first end of the eighth resistor (R67), the source is connected to the second end of the eighth resistor (R67), and the drain is connected to the output end of the LED internal power module; The second end of the sixth resistor (R24) is connected to the first end of the ninth resistor (R68); The second end of the seventh resistor (R25) is connected to the first end of the sixth resistor (R24); The first end of the eighth resistor (R67) is connected to the second end of the ninth resistor (R68); The first end of the ninth resistor (R68) is connected to the first end of the tenth resistor (R32); The first end of the tenth resistor (R32) is connected to the second end of the sixth resistor (R24), and the second end is connected to the output end of the LED internal power supply module.

6. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The power conversion circuit comprises a third MOS tube (Q5), a fourth MOS tube (Q6), a high-frequency transformer (T1) and an eleventh resistor (R15); The gate of the third MOS tube (Q5) is connected to the first end of the eleventh resistor (R15), the source is connected to the first end of the eleventh resistor (R15), and the drain is connected to the input end of the high-frequency transformer (T1); The gate of the fourth MOS tube (Q6) is connected to the input end of the high-frequency transformer (T1), the source is connected to the drain of the third MOS tube (Q5), and the drain is connected to the output end of the LED internal power module; The input end of the high-frequency transformer (T1) is connected to the drain of the third MOS transistor and the gate of the fourth MOS transistor (Q6), respectively, and the output end is connected to the input end of the output rectifier filter circuit; The first end of the eleventh resistor (R15) is connected to the source of the third MOS transistor, and the second end is grounded.

7. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The output rectifier filter circuit comprises an inductor (L1), a fifth MOS transistor (Q3), a sixth MOS transistor (Q4), a seventh MOS transistor (Q2), a seventh capacitor (C3), an eighth capacitor (C12), a ninth capacitor (C8), a tenth capacitor (C9), and an eleventh capacitor (C6); The first end of the inductor (L1) is connected to the output end of the LED internal power supply module, and the second end is connected to the first end of the seventh capacitor (C3); The gate of the fifth MOS tube (Q3) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module; The gate of the sixth MOS tube (Q4) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module; The gate of the seventh MOS tube (Q2) is connected to the second end of the power management chip (U1), the source is grounded, and the drain is connected to the output end of the LED internal power module; The first end of the seventh capacitor (C3) is connected to the second end of the inductor (L1), and the second end is grounded; A first end of the eighth capacitor (C12) is connected to a first end of the seventh capacitor (C3), and a second end is grounded; A first end of the ninth capacitor (C8) is connected to a first end of the eighth capacitor (C12), and a second end is grounded; The first end of the tenth capacitor (C9) is connected to the first end of the ninth capacitor (C8), and the second end is grounded; The first end of the eleventh capacitor (C6) is connected to the first end of the power management chip (U1), and the second end is grounded.

8. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 1 is characterized in that: The power management chip (U1) is an eight-pin chip.

9. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 2 is characterized in that: The first resistor (F1) includes any one of a fast fuse, a slow fuse, a polysilicon fuse and a smart fuse.

10. The high-power and high-reliability DC power supply for subway LED guide screen according to claim 2 is characterized in that: The second resistor (RT2) includes any one of a metal oxide varistor and a varistor ceramic resistor.

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