Power switch cabinet dehumidification control system based on semiconductor chilling plate

Abstract

The invention provides an electric switch cabinet dehumidification control system based on a semiconductor chilling plate, which solves the problems of dehumidification control in a switch cabinet and the like, and comprises a microprocessor U3, the microprocessor U3 is connected with a power supply circuit, a serial port communication circuit, a power supply voltage detection circuit, a temperature sampling circuit, a direct current fan driving and running current detection circuit, a semiconductor chilling plate driving and running current detection circuit and an air humidity sensor detection circuit, and the microprocessor U3 is connected with an interface circuit. The system has the advantages of good control effect, high automation degree and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of power control, and in particular relates to a dehumidification control system for a power switch cabinet based on a semiconductor refrigeration sheet. Background Art

[0002] Power switchgear is widely used in power supply systems of power stations. In order to ensure reliability and safety, it is generally highly closed, compact in structure, small in internal space, relatively closed and poor in air circulation, and often enters humid air due to lax sealing, underground moisture, rainy season and other reasons; when the air humidity is too high, condensation is easy to occur in the cabinet, causing the insulation parts to be damp, which reduces the performance and life of the components, accelerates metal corrosion, oxidizes the contact surface, increases the contact resistance, and causes the insulation strength of high-voltage electrical equipment to seriously decrease, leading to accidents. Therefore, moisture-proof and dehumidification have become important factors to ensure the safe and stable operation of switchgear. The general traditional treatment method is to install electric heaters, fans, desiccants in the cabinet or seal the cabinet. These measures can solve the problems of moisture and condensation in the cabinet in a short time, but they cannot solve the problem of moisture in the cabinet.

[0003] In order to solve the deficiencies of the existing technology, people have conducted long-term exploration and proposed various solutions. For example, a Chinese patent document discloses a switch cabinet intelligent dehumidification system with a timed dehumidification function [201520584515.0], which includes a CPU with a timing function and a power module connected thereto, a 485 communication module, a temperature and humidity acquisition module, a semiconductor condenser component, a fan, an indicator light, a button and a human-machine interface, wherein the CPU can set the dehumidification start and stop time, and the automatic timed dehumidification function will be realized within the set time every day, the temperature and humidity acquisition module collects the temperature and humidity data inside the electrical equipment and transmits the data to the CPU, the 485 communication module transmits the temperature and humidity data and the CPU working status to the host computer, and transmits the host computer instructions to the CPU, and the semiconductor condenser component and the fan are used for dehumidification.

[0004] The above solution solves the problem of dehumidification inside the switch cabinet to a certain extent, but the solution still has many shortcomings, such as low degree of automation and poor power regulation effect of the dehumidification system. Summary of the invention

[0005] The purpose of the present invention is to provide a power switch cabinet dehumidification control system based on semiconductor refrigeration sheets with reasonable design and flexible adjustment of dehumidification power in view of the above problems.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: a dehumidification control system for a power switch cabinet based on a semiconductor refrigeration plate, including a microprocessor U3, the microprocessor U3 is connected to a power supply circuit, a serial communication circuit, a power supply voltage detection circuit, a temperature sampling circuit, a DC fan drive and operating current detection circuit, a semiconductor refrigeration plate drive and operating current detection circuit and an air humidity sensor detection circuit, and the microprocessor U3 is connected to an interface circuit.

[0007] In the above-mentioned dehumidification control system of the power switch cabinet based on semiconductor refrigeration plate, the power supply end of the microprocessor U3 is connected to the decoupling capacitors C16, C17, C18 and C19 connected in parallel to the ground, the reset end of the microprocessor U3 is connected to the reset resistor R31 and the reset capacitor C43 connected to the ground, the clock signal of the microprocessor U3 uses an external oscillator, the input and output pins of the external oscillator are connected to the two ends of the passive crystal oscillator Y12, and the two ends of the passive crystal oscillator Y12 are respectively connected in parallel with two grounded load capacitors C20 and C21; the data line and clock line of the program debugging port of the microprocessor U3 are pulled up by resistors R32 and R33 respectively.

[0008] In the above-mentioned dehumidification control system of the power switch cabinet based on semiconductor refrigeration plate, the power supply circuit includes a voltage-stabilizing power supply chip U1 and a voltage-stabilizing power supply chip U2; the input end of the voltage-stabilizing power supply chip U1 is connected to the input power supply through the anti-reverse connection diode Ds and the filter capacitors C10 and C11, and the output end of the voltage-stabilizing power supply chip U2 is connected to the grounded filter capacitors C12 and C13, and the voltage-stabilizing power supply chip U1 outputs 5V current and inputs it to the input end of the voltage-stabilizing power supply chip U2; the output end of the voltage-stabilizing power supply chip U2 is connected to the capacitors C14 and C15 connected in parallel to the ground, and the voltage-stabilizing power supply chip U2 outputs 3.3V current to each power supply circuit; the power supply circuit has a power indication circuit composed of a current-limiting resistor R30 and a light-emitting diode LEDi.

[0009] In the above-mentioned power switch cabinet dehumidification control system based on semiconductor refrigeration plate, the serial communication circuit includes a current limiting protection resistor R27 arranged on the communication transmission line, a current limiting protection resistor R28 arranged on the communication receiving line and a protection resistor R29 arranged on the communication grounding line.

[0010] In the above-mentioned dehumidification control system of the power switch cabinet based on the semiconductor refrigeration plate, the temperature sampling circuit includes a first temperature sampling interface and a second temperature sampling interface; the first temperature sampling interface includes an RC filter circuit composed of voltage-dividing resistors R40 and R41 connected to the power circuit and a grounded capacitor C22; the second temperature sampling interface includes an RC filter circuit composed of voltage-dividing resistors R42 and R43 connected to the power circuit and a grounded capacitor C23.

[0011] In the above-mentioned dehumidification control system of the power switch cabinet based on the semiconductor refrigeration plate, the power supply voltage detection circuit has a power supply voltage divider circuit composed of a resistor R44 and a resistor R45, the power supply voltage detection circuit has an RC filter circuit composed of a resistor R46 and a capacitor C21, and the power supply voltage detection circuit has a voltage clamping protection circuit composed of diodes D2 and D3.

[0012] In the above-mentioned dehumidification control system of the power switch cabinet based on semiconductor refrigeration plate, the DC fan drive and operation current detection circuit includes a power driver U5, the input control end of the power driver U5 is connected to the current limiting resistor R1, the diagnostic control end of the power driver U5 is connected to the current limiting resistor R2, the power driver U5 is connected to the current detection resistor Rsf, the power driver U5 is connected to the filter circuit for current sampling composed of capacitor C1 and resistor R3, the current sampling channel switching control end of the power driver U5 is connected to the current limiting resistor R4, the input control end of the power driver U5 is connected to the current limiting resistor R5, the output channel of the power driver U5 is connected to the pull-down circuit with the current limiting resistor R6 and the filter capacitor C2, and the output channel of the power driver U5 is connected to the pull-down circuit with the current limiting resistor R7 and the filter capacitor C3.

[0013] In the above-mentioned dehumidification control system of the power switch cabinet based on semiconductor refrigeration film, the semiconductor refrigeration film driving and operating current detection circuit includes a power driver U6, the input control end of the power driver U6 is connected to the current limiting resistor R11, the diagnostic control end of the power driver U6 is connected to the current limiting resistor R12, the power driver U6 is connected to the current detection resistor RsT1, the power driver U6 is connected to the filter circuit for current sampling composed of a capacitor C11 and a resistor R13, the current sampling channel switching control end of the power driver U6 is connected to the current limiting resistor R14, and the input control end of the power driver U6 is connected to the current limiting resistor R15; the semiconductor refrigeration film driving and operating current detection circuit has a power switch module Q5 and an H-bridge circuit; the H-bridge circuit includes transistors Q1 and Q2; the transistor Q1 is connected to resistors R17, R18, R19, R20 and a voltage-stabilizing diode Dz1; the transistor Q2 is connected to resistors R21, R22, R23, R24 and a voltage-stabilizing diode Dz2.

[0014] In the above-mentioned dehumidification control system of the power switch cabinet based on the semiconductor refrigeration chip, the interface circuit includes the positive and negative plug-in pins of the semiconductor refrigeration chip control, the temperature sensor collection input pin, the fan control output plug-in pin, the 12V power supply input pin and the serial communication transceiver pin.

[0015] In the above-mentioned dehumidification control system of the power switch cabinet based on semiconductor refrigeration sheet, the air humidity sensor circuit includes an air humidity sampling chip U4, an electrostatic protection chip ESD, and a power protection diode TVS; the power input end of the air humidity sampling chip U4 passes through two filter capacitors C5 and C6, and the SDA end and SCL end of the air humidity sampling chip U4 are respectively connected to IIC_SDA and IIC_SCL of the microprocessor U3 and are respectively connected in parallel with two high-frequency filter capacitors C3 and C7 to ground.

[0016] Compared with the existing technology, the advantages of the present invention are: the entire control system combines real-time collection of air temperature and humidity, and temperature and humidity threshold setting for automatic closed-loop control, which can realize fully automatic control of temperature and humidity in the cabinet, and has a short working time, no vibration of electrical parts, small space occupation and little impact on the operation of other equipment, thereby flexibly controlling the power of the dehumidification system; creating condensation conditions in local areas so that the humid air in the cabinet condenses into water and is directly discharged out of the cabinet, thereby reducing the relative humidity of the air in the cabinet, which can fundamentally solve the internal humidity of electrical equipment and inhibit the occurrence of condensation; it has its own overheating protection and fault diagnosis mechanism, thereby ensuring the overall stability of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an overall schematic diagram of the present invention;

[0018] Figure 2 is a circuit schematic diagram of the microprocessor U3 of the present invention;

[0019] Figure 3 It is a schematic diagram of a power supply circuit of the present invention;

[0020] Figure 4 It is a circuit principle diagram of the serial communication circuit of the present invention;

[0021] Figure 5 It is the principle diagram of the temperature sampling circuit and the power supply voltage detection circuit of the present invention;

[0022] Figure 6 It is a circuit schematic diagram of a DC fan driving and operating current detection circuit of the present invention;

[0023] Figure 7 It is a circuit principle diagram of the semiconductor refrigeration plate driving and operating current detection circuit of the present invention;

[0024] Figure 8 is a circuit schematic diagram of the interface circuit of the present invention;

[0025] Fig. 9 It is a circuit principle diagram of the air humidity sensor detection circuit of the present invention;

[0026] In the figure, there are power supply circuit 1, serial communication circuit 2, temperature sampling circuit 3, DC fan drive and operation current detection circuit 4, semiconductor refrigeration chip drive and operation current detection circuit 5, air humidity sensor detection circuit 6, power supply voltage detection circuit 7, and interface circuit 8. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1-9 As shown, a dehumidification control system for a power switch cabinet based on a semiconductor refrigeration plate includes a microprocessor U3, the microprocessor U3 is connected to a power circuit 1, a serial communication circuit 2, a power voltage detection circuit 7, a temperature sampling circuit 3, a DC fan drive and operation current detection circuit 4, a semiconductor refrigeration plate drive and operation current detection circuit 5 and an air humidity sensor detection circuit 6, and the microprocessor U3 is connected to an interface circuit 8. The semiconductor refrigeration plate drive and operation current detection circuit 5 controls the semiconductor refrigeration plate to realize a bidirectional function of cooling or heating, the DC fan drive and operation current detection circuit 4 controls the fan to run or stop, the temperature sampling circuit 3 is connected to an external temperature sensor to realize real-time temperature detection and semiconductor refrigeration plate overheat protection, the air humidity sensor detection circuit 6 realizes real-time collection of air humidity for real-time feedback of the dehumidification effect, and the serial communication circuit 2 realizes the configuration of automatic control parameters and fault diagnosis functions.

[0029] Specifically, the microprocessor U3 automatically controls the operation of the semiconductor refrigeration plate and the fan by collecting the real-time amount of temperature and air humidity and the control parameter threshold set by serial communication. The power supply end of the microprocessor U3 is connected to the decoupling capacitors C16, C17, C18 and C19 connected in parallel to the ground, the reset end of the microprocessor U3 is connected to the reset resistor R31 and the reset capacitor C43 connected to the ground, the clock signal of the microprocessor U3 uses an external oscillator, the input and output pins of the external oscillator are connected to the two ends of the passive crystal oscillator Y12, and the two ends of the passive crystal oscillator Y12 are respectively connected in parallel to two grounded load capacitors C20 and C21; the data line and clock line of the program debugging port of the microprocessor U3 are pulled up by resistors R32 and R33 respectively.

[0030] In depth, the power supply circuit 1 includes a 12V power supply circuit, a 5V power supply circuit and a 3.3V power supply circuit. The 12V power supply circuit is used for 5V and 3.3V power supply input and semiconductor refrigeration plate driving and operating current detection circuit 5 level conversion. The 3.3V power supply circuit is used for powering the microprocessor U3, the temperature sampling circuit 3 voltage divider power supply, the air humidity sensor detection circuit 6 power supply and the logic power supply of its control chip.

[0031] The power supply circuit 1 specifically includes a voltage-stabilized power supply chip U1 and a voltage-stabilized power supply chip U2; the input end of the voltage-stabilized power supply chip U1 is connected to the input power supply through an anti-reverse connection diode Ds, filter capacitors C10 and C11, and the output end of the voltage-stabilized power supply chip U2 is connected to grounded filter capacitors C12 and C13, and the voltage-stabilized power supply chip U1 outputs a 5V current and inputs it to the input end of the voltage-stabilized power supply chip U2; the output end of the voltage-stabilized power supply chip U2 is connected to capacitors C14 and C15 connected in parallel to the ground, and the voltage-stabilized power supply chip U2 outputs a 3.3V current to each power supply circuit; the power supply circuit 1 has a power supply indication circuit composed of a current-limiting resistor R30 and a light-emitting diode LEDi, which is used to indicate a 3.3V power supply. The voltage-stabilized power supply chip U1 uses the model AMS1117-5.0, and the voltage-stabilized power supply chip U2 uses the model AMS1117-3.3.

[0032] Furthermore, the serial communication circuit 2 is used to configure control parameters such as the semiconductor refrigeration chip overheat protection temperature threshold, the dehumidification humidity threshold, and is also used to read information such as operation fault storage information. It includes a current limiting protection resistor R27 set on the communication transmission line, a current limiting protection resistor R28 set on the communication receiving line, and a protection resistor R29 set on the communication ground line.

[0033] Furthermore, the temperature sampling circuit 3 is used for real-time temperature acquisition, which is used for overheat protection during the operation of the semiconductor refrigeration plate on the one hand, and for real-time dehumidification control logic on the other hand. It includes a first temperature sampling interface and a second temperature sampling interface; the first temperature sampling interface includes an RC filter circuit composed of voltage-dividing resistors R40 and R41 connected to the power supply circuit 1 and a grounded capacitor C22; the second temperature sampling interface includes an RC filter circuit composed of voltage-dividing resistors R42 and R43 connected to the power supply circuit 1 and a grounded capacitor C23.

[0034] In addition, the power supply voltage detection circuit 7 is used for real-time power supply voltage detection to protect the semiconductor refrigeration chip from operating within the rated operating voltage range to extend its life; it has a power supply voltage divider circuit composed of a resistor R44 and a resistor R45, the power supply voltage detection circuit has an RC filter circuit composed of a resistor R46 and a capacitor C21, and the power supply voltage detection circuit has a voltage clamping protection circuit composed of diodes D2 and D3.

[0035] At the same time, the DC fan drive and operation current detection circuit 4 controls the fan to start or stop running, which is used for heat dissipation of semiconductor refrigeration plates and air circulation in the cabinet, and can monitor the fan current in real time. Specifically, it includes a power driver U5, the input control end of the power driver U5 is connected to a current limiting resistor R1, the diagnostic control end of the power driver U5 is connected to a current limiting resistor R2, the power driver U5 is connected to a current detection resistor Rsf, the power driver U5 is connected to a filter circuit for current sampling composed of a capacitor C1 and a resistor R3, the current sampling channel switching control end of the power driver U5 is connected to a current limiting resistor R4, the input control end of the power driver U5 is connected to a current limiting resistor R5, the output channel of the power driver U5 is connected to a pull-down circuit with a current limiting resistor R6 and a filter capacitor C2, the output channel of the power driver U5 is connected to a pull-down circuit with a current limiting resistor R7 and a filter capacitor C3, and the power driver U5 uses BTS5120-2EKA.

[0036] It can be seen that the semiconductor refrigeration plate driving and operating current detection circuit 5 is used to control the semiconductor refrigeration and heating power and monitor the semiconductor current. It includes a power driver U6, the input control end of the power driver U6 is connected to the current limiting resistor R11, the diagnostic control end of the power driver U6 is connected to the current limiting resistor R12, the power driver U6 is connected to the current detection resistor RsT1, the power driver U6 is connected to the filter circuit for current sampling composed of a capacitor C11 and a resistor R13, the current sampling channel switching control end of the power driver U6 is connected to the current limiting resistor R14, and the input control end of the power driver U6 is connected to the current limiting resistor R15; the semiconductor refrigeration plate driving and operating current detection circuit has a power switch module Q5 and an H-bridge circuit; the H-bridge circuit includes transistors Q1 and Q2; the transistor Q1 is connected to resistors R17, R18, R19, R20 and a voltage stabilizing diode Dz1; the transistor Q2 is connected to resistors R21, R22, R23, R24 and a voltage stabilizing diode Dz2.

[0037] Obviously, the interface circuit 8 includes the positive and negative plug-in pins for controlling the semiconductor refrigeration chip, the temperature sensor collection input pin, the fan control output plug-in pin, the 12V power supply input pin and the serial communication transceiver pin.

[0038] Preferably, the air humidity sensor circuit 6 is used to collect the air humidity in real time and compare it with the set dehumidification humidity threshold, so as to control the operation of the semiconductor refrigeration chip. Specifically, it includes an air humidity sampling chip U4, an electrostatic protection chip ESD, and a power protection diode TVS; the power input end of the air humidity sampling chip U4 passes through two filter capacitors C5 and C6, and the SDA end and SCL end of the air humidity sampling chip U4 are respectively connected to IIC_SDA and IIC_SCL of the microprocessor U3 and are respectively connected in parallel with two high-frequency filter capacitors C3 and C7 to the ground, and the air humidity sampling chip U4 uses HDC1080.

[0039] To sum up, the principle of this embodiment is that the microprocessor U3 serves as the control core, and the semiconductor refrigeration plate drive and operating current detection circuit 5 and the DC fan drive and operating current detection circuit 4 connected to it control the semiconductor and fan power and monitor the current and voltage in real time. The temperature sampling circuit 3 and the air humidity sensor detection circuit 6 connected to the microprocessor U3 feedback the temperature and humidity, and feedback-adjust the power of the semiconductor refrigeration plate to realize dynamic adjustment of the temperature and humidity, so that condensation conditions are created in the local area inside the switch cabinet, so that the humid air in the cabinet condenses into water and is directly discharged outside the cabinet.

[0040] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0041] Although this article uses more terms such as power supply circuit 1, serial communication circuit 2, temperature sampling circuit 3, DC fan drive and operation current detection circuit 4, semiconductor refrigeration chip drive and operation current detection circuit 5, air humidity sensor detection circuit 6, power supply voltage detection circuit 7, interface circuit 8, etc., it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A dehumidification control system for a power switch cabinet based on a semiconductor refrigeration sheet, comprising a microprocessor U3, characterized in that: The microprocessor U3 is connected to a power supply circuit (1), a serial communication circuit (2), a power supply voltage detection circuit (7), a temperature sampling circuit (3), a DC fan drive and operating current detection circuit (4), a semiconductor refrigeration plate drive and operating current detection circuit (5) and an air humidity sensor detection circuit (6), and the microprocessor U3 is connected to an interface circuit (8).

2. According to claim 1, a dehumidification control system for a power switch cabinet based on a semiconductor refrigeration sheet is characterized in that: The power supply end of the microprocessor U3 is connected to decoupling capacitors C16, C17, C18 and C19 connected in parallel to the ground; the reset end of the microprocessor U3 is connected to a reset resistor R31 and a reset capacitor C43 connected to the ground; the clock signal of the microprocessor U3 uses an external oscillator, and the input and output pins of the external oscillator are connected to the two ends of the passive crystal oscillator Y12; the two ends of the passive crystal oscillator Y12 are respectively connected in parallel to two grounded load capacitors C20 and C21; the data line and clock line of the program debugging port of the microprocessor U3 are pulled up by resistors R32 and R33 respectively.

3. According to the semiconductor refrigeration sheet-based power switch cabinet dehumidification control system of claim 1, it is characterized in that: The power supply circuit (1) comprises a voltage-stabilized power supply chip U1 and a voltage-stabilized power supply chip U2; the input end of the voltage-stabilized power supply chip U1 is connected to the input power supply through an anti-reverse connection diode Ds and filter capacitors C10 and C11, the output end of the voltage-stabilized power supply chip U2 is connected to grounded filter capacitors C12 and C13, the voltage-stabilized power supply chip U1 outputs a 5V current and inputs it to the input end of the voltage-stabilized power supply chip U2; the output end of the voltage-stabilized power supply chip U2 is connected to capacitors C14 and C15 connected in parallel to the ground, and the voltage-stabilized power supply chip U2 outputs a 3.3V current to each power supply circuit; the power supply circuit (1) has a power indication circuit composed of a current-limiting resistor R30 and a light-emitting diode LEDi.

4. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1 is characterized in that: The serial communication circuit (2) comprises a current limiting protection resistor R27 arranged on a communication transmission line, a current limiting protection resistor R28 arranged on a communication reception line, and a protection resistor R29 arranged on a communication ground line.

5. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1 is characterized in that: The temperature sampling circuit (3) comprises a first temperature sampling interface and a second temperature sampling interface; the first temperature sampling interface comprises an RC filter circuit composed of voltage-dividing resistors R40 and R41 connected to the power supply circuit (1) and a grounded capacitor C22; the second temperature sampling interface comprises an RC filter circuit composed of voltage-dividing resistors R42 and R43 connected to the power supply circuit (1) and a grounded capacitor C23.

6. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1 is characterized in that: The power supply voltage detection circuit (7) has a power supply voltage divider circuit composed of a resistor R44 and a resistor R45, the power supply voltage detection circuit has an RC filter circuit composed of a resistor R46 and a capacitor C21, and the power supply voltage detection circuit has a voltage clamping protection circuit composed of diodes D2 and D3.

7. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1 is characterized in that: The DC fan driving and operating current detection circuit (4) comprises a power driver U5, an input control end of the power driver U5 is connected to a current limiting resistor R1, a diagnostic control end of the power driver U5 is connected to a current limiting resistor R2, the power driver U5 is connected to a current detection resistor Rsf, the power driver U5 is connected to a filter circuit for current sampling composed of a capacitor C1 and a resistor R3, a current sampling channel switching control end of the power driver U5 is connected to a current limiting resistor R4, an input control end of the power driver U5 is connected to a current limiting resistor R5, an output channel of the power driver U5 is connected to a pull-down circuit having a current limiting resistor R6 and a filter capacitor C2, and an output channel of the power driver U5 is connected to a pull-down circuit having a current limiting resistor R7 and a filter capacitor C3.

8. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1 is characterized in that: The semiconductor refrigeration plate driving and operating current detection circuit (5) comprises a power driver U6, the input control end of the power driver U6 is connected to a current limiting resistor R11, the diagnostic control end of the power driver U6 is connected to a current limiting resistor R12, the power driver U6 is connected to a current detection resistor RsT1, the power driver U6 is connected to a filter circuit for current sampling composed of a capacitor C11 and a resistor R13, the current sampling channel switching control end of the power driver U6 is connected to a current limiting resistor R14, and the input control end of the power driver U6 is connected to a current limiting resistor R15; the semiconductor refrigeration plate driving and operating current detection circuit comprises a power switch module Q5 and an H-bridge circuit; the H-bridge circuit comprises transistors Q1 and Q2; the transistor Q1 is connected to resistors R17, R18, R19, R20 and a voltage stabilizing diode Dz1; the transistor Q2 is connected to resistors R21, R22, R23, R24 and a voltage stabilizing diode Dz2.

9. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1, characterized in that: The interface circuit (8) comprises semiconductor cooling plate control positive and negative electrode plug-in pins, temperature sensor acquisition input pins, fan control output plug-in pins, 12V power supply input pins and serial communication transceiver pins.

10. The dehumidification control system for power switch cabinet based on semiconductor refrigeration sheet according to claim 1, characterized in that: The air humidity sensor circuit (6) comprises an air humidity sampling chip U4, an electrostatic protection chip ESD, and a power protection diode TVS; the power input end of the air humidity sampling chip U4 passes through two filter capacitors C5 and C6, and the SDA end and SCL end of the air humidity sampling chip U4 are respectively connected to IIC_SDA and IIC_SCL of the microprocessor U3 and are respectively connected in parallel with two high-frequency filter capacitors C3 and C7 to ground.

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