Air-conditioning air handling unit

Abstract

The utility model discloses an air-conditioning air handling unit, belongs to the technical field of air handling, and solves the problem that the air volume is increased or decreased due to misjudgment of an air feeder caused by poor contact of a 24V power supply line of a differential pressure sensor in the air-conditioning air handling unit. Comprising a machine case, a draught fan arranged in the machine case and a pressure difference sensor arranged on an air path in the machine case, the pressure difference sensor and the draught fan are jointly coupled with a draught fan electric measurement circuit, and the draught fan electric measurement circuit detects the voltage condition of the pressure difference sensor and switches a power supply and maintains normal operation of the draught fan when the voltage of the pressure difference sensor is abnormal. Through linkage of redundant power supply, real-time monitoring, signal isolation and intelligent control, the problem of fan misoperation caused by poor power supply contact of a differential pressure sensor is solved, and reliable operation of an air conditioning unit in a complex industrial environment is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of air handling technology, and in particular to an air conditioning air handling unit. Background Technology

[0002] Air handling units (ALUs) are devices used for centralized air treatment, widely used in commercial buildings, industrial sites, and large residences. They provide a comfortable and clean indoor air environment through a series of air handling processes, including cooling, heating, humidification, dehumidification, filtration, and ventilation. A typical ALU consists of a mixing section, a pre-filter section, a cooling coil section, a heating section, a humidification section, a fan section, and a supply air section. The mixing section introduces fresh and return air; the filtration section effectively removes dust and impurities from the air; the cooling coil and heating section regulate the air temperature; and the humidification and dehumidification sections control the air humidity. The fan section provides power to deliver the treated air into the room. ALUs are characterized by high efficiency, energy saving, and stability, meeting the air quality requirements of different locations and creating a healthy and comfortable indoor environment.

[0003] However, a faulty 24V power supply line of the differential pressure sensor in the air handling unit caused the blower to misjudge and increase or decrease the air volume.

[0004] Therefore, an air handling unit is proposed to solve or alleviate the above problems. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of existing technologies by proposing an air handling unit.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An air handling unit includes a chassis, a fan installed inside the chassis, and a differential pressure sensor installed on the air duct inside the chassis. The differential pressure sensor and the fan are coupled together to a fan electrical measurement circuit. The fan electrical measurement circuit detects the voltage of the differential pressure sensor and switches the power supply to maintain normal operation of the fan when the voltage of the differential pressure sensor is abnormal.

[0008] Preferably, the wind turbine electrical measurement circuit includes a main power input module, a backup power module, a redundancy switching module, a voltage monitoring module, a signal filtering and isolation module, a control system, and a wind turbine drive circuit;

[0009] The output terminal of the main power input module is connected to the main power input terminal of the redundancy switching module, the output terminal of the backup power module is connected to the backup power input terminal of the redundancy switching module, and the power output terminal of the redundancy switching module is connected to the power input terminal of the differential pressure sensor.

[0010] The input terminal of the voltage monitoring module is connected to the output terminal of the main power input module, and its alarm signal output terminal is connected to the digital input port of the control system. The voltage monitoring module monitors the voltage status of the main power input module in real time and feeds back the alarm signal to the control system.

[0011] The differential pressure sensor signal output terminal is connected to the input terminal of the signal filtering and isolation module, and the output terminal of the signal filtering and isolation module is connected to the analog input port of the control system. The signal output by the differential pressure sensor is processed by the signal filtering and isolation module and then transmitted to the control system.

[0012] The control signal output terminal of the control system is connected to the speed regulation input terminal of the fan drive circuit, and the drive output terminal of the fan drive circuit is connected to the motor winding of the fan. The control system controls the fan drive circuit according to the differential pressure signal and the alarm signal to adjust the speed of the blower.

[0013] Preferably, the main power input module includes a fuse and a TVS diode. One end of the fuse is connected to the positive terminal of an external 24V power supply, and the other end is connected to the anode of the TVS diode. The cathode of the TVS diode outputs the main power supply voltage, and the anode of the TVS diode is grounded.

[0014] Preferably, the backup power module includes a supercapacitor and a charging management chip TP4056. The input pin of the charging management chip TP4056 receives the main power supply voltage, the output pin of the charging management chip TP4056 is connected to the positive terminal of the supercapacitor, and the negative terminal of the supercapacitor is grounded.

[0015] Preferably, the redundancy switching module includes a Schottky diode SS34 and a MOSFET. The anode of the Schottky diode SS34 receives the main power supply voltage, the cathode of the Schottky diode SS34 is connected to the power supply node of the differential pressure sensor, the source of the MOSFET is connected to the positive terminal of the supercapacitor, the drain of the MOSFET is connected to the sensor power supply node, and the gate of the MOSFET is connected to the output terminal of the voltage monitoring module.

[0016] Preferably, the voltage monitoring module includes a reference source TL431, a voltage divider resistor, a comparator LM393, and an optocoupler PC817. The reference pin of the reference source TL431 is connected to the main power supply voltage through the voltage divider resistor. The cathode of the reference source TL431 is connected to the voltage divider resistor, and the pin of the voltage divider resistor is grounded. The cathode of the reference source TL431 is connected to the non-inverting input of the comparator LM393. The inverting input of the comparator LM393 is connected to a 2.5V reference voltage. The output of the comparator LM393 is connected to the anode of the LED of the optocoupler PC817. The cathode of the LED of the optocoupler PC817 is grounded. The output of the optocoupler PC817 is connected to the digital input pin of the control system.

[0017] Preferably, the signal filtering and isolation module includes an RC low-pass filter, a linear optocoupler HCNR201, and an operational amplifier OPA2188. The input terminal of the RC low-pass filter is connected to the signal output terminal of the differential pressure sensor. The input terminal of the linear optocoupler HCNR201 is connected to the output terminal of the RC filter, and its output terminal is connected to the non-inverting input terminal of the operational amplifier OPA2188. The output terminal of the operational amplifier OPA2188 is connected to the analog input port of the control system.

[0018] Preferably, the control system includes a PLC, the fan drive circuit includes a frequency converter ACS550, the alarm input terminal of the PLC is connected to the output terminal of the optocoupler PC817, the analog input terminal of the PLC is coupled to the output terminal of the operational amplifier OPA2188, the analog output terminal of the PLC is coupled to the command input terminal of the frequency converter ACS550, and the motor drive output terminal of the frequency converter ACS550 is connected to the three-phase winding of the fan.

[0019] This utility model has the following beneficial effects:

[0020] This invention solves the problem of fan malfunction caused by poor power supply contact of differential pressure sensors by using redundant power supply, real-time monitoring, signal isolation and intelligent control linkage, thus ensuring the reliable operation of air conditioning units in complex industrial environments. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a structural block diagram of the electrical measurement circuit for the wind turbine in this utility model.

[0024] 1. Chassis; 2. Main power input module; 3. Backup power module; 4. Redundancy switching module; 5. Voltage monitoring module; 6. Differential pressure sensor; 7. Signal filtering and isolation module; 8. Control system; 9. Fan drive circuit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0030] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] An air handling unit, such as Figure 1 As shown, it includes a chassis 1, a fan installed inside the chassis 1, and a differential pressure sensor 6 installed on the air duct inside the chassis 1. The differential pressure sensor 6 and the fan are coupled together to a fan electrical measurement circuit. The fan electrical measurement circuit detects the voltage of the differential pressure sensor 6 and switches the power supply to maintain the normal operation of the fan when the voltage of the differential pressure sensor 6 is abnormal.

[0032] like Figure 2 As shown, the wind turbine electrical measurement circuit includes a main power input module 2, a backup power module 3, a redundancy switching module 4, a voltage monitoring module 5, a signal filtering and isolation module 7, a control system 8, and a wind turbine drive circuit 9. The output of the main power input module 2 is connected to the main power input of the redundancy switching module 4. The output of the backup power module 3 is connected to the backup power input of the redundancy switching module 4. The power output of the redundancy switching module 4 is connected to the power input of the differential pressure sensor 6. The input of the voltage monitoring module 5 is connected to the output of the main power input module 2, and its alarm signal output is connected to the digital input port of the control system 8. Block 5 monitors the voltage status of the main power input module 2 in real time and feeds back an alarm signal to the control system 8. The signal output terminal of the differential pressure sensor 6 is connected to the input terminal of the signal filtering and isolation module 7. The output terminal of the signal filtering and isolation module 7 is connected to the analog input port of the control system 8. The signal output by the differential pressure sensor 6 is processed by the signal filtering and isolation module 7 and then transmitted to the control system 8. The control signal output terminal of the control system 8 is connected to the speed regulation input terminal of the fan drive circuit 9. The drive output terminal of the fan drive circuit 9 is connected to the motor winding of the fan. The control system 8 controls the fan drive circuit 9 according to the differential pressure signal and the alarm signal to adjust the speed of the blower.

[0033] The main power input module 2 includes a fuse and a TVS diode. One end of the fuse is connected to the positive terminal of an external 24V power supply, and the other end is connected to the anode of the TVS diode. The cathode of the TVS diode outputs the main power supply voltage, and the anode of the TVS diode is grounded.

[0034] The backup power module 3 includes a supercapacitor and a charging management chip TP4056. The input pin of the charging management chip TP4056 receives the main power supply voltage, and the output pin of the charging management chip TP4056 is connected to the positive terminal of the supercapacitor, while the negative terminal of the supercapacitor is grounded.

[0035] The redundancy switching module 4 includes a Schottky diode SS34 and a MOSFET. The anode of the Schottky diode SS34 receives the main power supply voltage, the cathode of the Schottky diode SS34 is connected to the power supply node of the differential pressure sensor 6, the source of the MOSFET is connected to the positive terminal of the supercapacitor, the drain of the MOSFET is connected to the sensor power supply node, and the gate of the MOSFET is connected to the output terminal of the voltage monitoring module 5.

[0036] The voltage monitoring module 5 includes a reference source TL431, a voltage divider resistor, a comparator LM393, and an optocoupler PC817. The reference pin of the reference source TL431 is connected to the main power supply voltage through the voltage divider resistor. The cathode of the reference source TL431 is connected to the voltage divider resistor, and the pin of the voltage divider resistor is grounded. The cathode of the reference source TL431 is connected to the non-inverting input of the comparator LM393. The inverting input of the comparator LM393 is connected to a 2.5V reference voltage. The output of the comparator LM393 is connected to the anode of the LED of the optocoupler PC817. The cathode of the LED of the optocoupler PC817 is grounded. The output of the optocoupler PC817 is connected to the digital input pin of the control system 8.

[0037] The signal filtering and isolation module 7 includes an RC low-pass filter, a linear optocoupler HCNR201, and an operational amplifier OPA2188. The input of the RC low-pass filter is connected to the signal output of the differential pressure sensor 6. The input of the linear optocoupler HCNR201 is connected to the output of the RC filter, and its output is connected to the non-inverting input of the operational amplifier OPA2188. The output of the operational amplifier OPA2188 is connected to the analog input port of the control system 8.

[0038] The control system 8 includes a PLC, and the fan drive circuit 9 includes a frequency converter ACS550. The alarm input terminal of the PLC is connected to the output terminal of the optocoupler PC817, the analog input terminal of the PLC is coupled to the output terminal of the operational amplifier OPA2188, the analog output terminal of the PLC is coupled to the command input terminal of the frequency converter ACS550, and the motor drive output terminal of the frequency converter ACS550 is connected to the three-phase winding of the fan.

[0039] This utility model circuit achieves stable power supply and fan control for the differential pressure sensor 6 in the air handling unit through the coordinated operation of multiple modules. Its working principle is as follows:

[0040] The main power input module 2 receives an external 24V DC power supply. After overcurrent protection by the fuse and surge suppression by the TVS diode, it outputs a clean main power voltage. This main power voltage powers the differential pressure sensor 6 directly through the Schottky diode SS34 of the redundant switching module 4, and also charges the supercapacitor through the charging management chip TP4056 to form a backup power supply. The voltage monitoring module 5 collects the main power voltage in real time and sets a 22V threshold through the reference source TL431 and the voltage divider resistor. When the main power voltage drops, the comparator LM393 outputs a low level to trigger the optocoupler PC817 to send an alarm signal to the control system 8. At the same time, it drives the MOSFET to turn on, so that the energy stored in the supercapacitor is seamlessly switched to the sensor power supply circuit through the low impedance path of the MOSFET, ensuring that the sensor continues to operate during power failure.

[0041] The 4-20mA signal output by differential pressure sensor 6 is filtered by an RC filter to remove high-frequency harmonics generated by the inverter ACS550, then is potential isolated by a linear optocoupler HCNR201, and finally buffered and conditioned by an operational amplifier OPA2188. The interference-free analog signal is then sent to the analog input pin of the control system 8. The control system 8 dynamically adjusts the 0-10V output of the analog output pin according to the differential pressure signal, and controls the inverter ACS550 to drive the blower to achieve speed regulation. When the digital input pin detects a power supply alarm, it immediately freezes the speed regulation command, forces the blower to run at 50% safe speed, and uploads the fault code through the RS485 interface to trigger a remote maintenance response.

[0042] The fan electrical measurement circuit in this invention significantly shortens the power supply switching time through dual power supply redundancy and mixed switching of MOSFETs and diodes. The supercapacitor can support the differential pressure sensor 6 to work continuously for 10 minutes, completely eliminating signal interruption caused by poor contact. In addition, RC filtering and linear optocoupler dual isolation control the signal transmission error and effectively resist electromagnetic interference in the environment. Overall, it can also prevent the air handling unit from misjudging the air supply fan and increasing or decreasing the air volume due to poor contact of the 24V power supply line of the differential pressure sensor 6.

[0043] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An air conditioning air handling unit, comprising: Includes a chassis (1), a fan installed inside the chassis (1), and a differential pressure sensor (6) installed on the air duct inside the chassis (1). The differential pressure sensor (6) and the fan are coupled together to a fan electrical measurement circuit. The fan electrical measurement circuit detects the voltage of the differential pressure sensor (6) and switches the power supply and maintains the normal operation of the fan when the voltage of the differential pressure sensor (6) is abnormal.

2. An air handling unit as set forth in claim 1, characterized in that, The wind turbine electrical measurement circuit includes a main power input module (2), a backup power module (3), a redundancy switching module (4), a voltage monitoring module (5), a signal filtering and isolation module (7), a control system (8), and a wind turbine drive circuit (9). The output terminal of the main power input module (2) is connected to the main power input terminal of the redundancy switching module (4), the output terminal of the backup power module (3) is connected to the backup power input terminal of the redundancy switching module (4), and the power output terminal of the redundancy switching module (4) is connected to the power input terminal of the differential pressure sensor (6). The input terminal of the voltage monitoring module (5) is connected to the output terminal of the main power input module (2), and its alarm signal output terminal is connected to the digital input port of the control system (8). The voltage monitoring module (5) monitors the voltage status of the main power input module (2) in real time and feeds back the alarm signal to the control system (8). The signal output terminal of the differential pressure sensor (6) is connected to the input terminal of the signal filtering and isolation module (7), and the output terminal of the signal filtering and isolation module (7) is connected to the analog input port of the control system (8). The signal output by the differential pressure sensor (6) is processed by the signal filtering and isolation module (7) and then transmitted to the control system (8). The control signal output terminal of the control system (8) is connected to the speed regulation input terminal of the fan drive circuit (9), and the drive output terminal of the fan drive circuit (9) is connected to the motor winding of the fan. The control system (8) controls the fan drive circuit (9) according to the differential pressure signal and the alarm signal to adjust the speed of the blower.

3. An air handling unit as set forth in claim 2, wherein, The main power input module (2) includes a fuse and a TVS diode. One end of the fuse is connected to the positive terminal of an external 24V power supply, and the other end is connected to the anode of the TVS diode. The cathode of the TVS diode outputs the main power supply voltage, and the anode of the TVS diode is grounded.

4. An air handling unit as set forth in claim 3, wherein, The backup power module (3) includes a supercapacitor and a charging management chip TP4056. The input pin of the charging management chip TP4056 receives the main power supply voltage, and the output pin of the charging management chip TP4056 is connected to the positive terminal of the supercapacitor. The negative terminal of the supercapacitor is grounded.

5. An air handling unit according to claim 4, characterized in that, The redundancy switching module (4) includes a Schottky diode SS34 and a MOS transistor. The anode of the Schottky diode SS34 receives the main power supply voltage, the cathode of the Schottky diode SS34 is connected to the power supply node of the differential pressure sensor (6), the source of the MOS transistor is connected to the positive terminal of the supercapacitor, the drain of the MOS transistor is connected to the power supply node of the sensor, and the gate of the MOS transistor is connected to the output terminal of the voltage monitoring module (5).

6. An air handling unit as set forth in claim 3, wherein, The voltage monitoring module (5) includes a reference source TL431, a voltage divider resistor, a comparator LM393, and an optocoupler PC817. The reference pin of the reference source TL431 is connected to the main power supply voltage through the voltage divider resistor. The cathode of the reference source TL431 is connected to the voltage divider resistor, and the pin of the voltage divider resistor is grounded. The cathode of the reference source TL431 is connected to the non-inverting input of the comparator LM393. The inverting input of the comparator LM393 is connected to a 2.5V reference voltage. The output of the comparator LM393 is connected to the anode of the LED of the optocoupler PC817. The cathode of the LED of the optocoupler PC817 is grounded. The output of the optocoupler PC817 is connected to the digital input pin of the control system (8).

7. An air handling unit as set forth in claim 6, wherein, The signal filtering and isolation module (7) includes an RC low-pass filter, a linear optocoupler HCNR201, and an operational amplifier OPA2188. The input of the RC low-pass filter is connected to the signal output of the differential pressure sensor (6). The input of the linear optocoupler HCNR201 is connected to the output of the RC filter, and its output is connected to the non-inverting input of the operational amplifier OPA2188. The output of the operational amplifier OPA2188 is connected to the analog input port of the control system (8).

8. An air handling unit as set forth in claim 7, wherein, The control system (8) includes a PLC, the fan drive circuit (9) includes a frequency converter ACS550, the alarm input terminal of the PLC is connected to the output terminal of the optocoupler PC817, the analog input terminal of the PLC is coupled to the output terminal of the operational amplifier OPA2188, the analog output terminal of the PLC is coupled to the command input terminal of the frequency converter ACS550, and the motor drive output terminal of the frequency converter ACS550 is connected to the three-phase winding of the fan.

Images