A non-intrusive energy-saving control device for centralized air conditioning systems

Abstract

This invention discloses a non-intrusive energy-saving control device for centralized air conditioning systems, comprising an intelligent control platform N1, a first signal switching switch N21, a second signal switching switch N22, a data gateway for energy-saving retrofitted air conditioning units N31, a control cabinet for energy-saving retrofitted chilled / hot water pumps of the air conditioning units N32, a control cabinet for energy-saving retrofitted cooling water pumps of the air conditioning units N33, and a control cabinet for energy-saving retrofitted cooling towers N34. This invention also provides hardware circuitry for multi-type signal differential input protection circuits and a Modbus RTU-to-TCP protocol data gateway. This invention enables online energy-saving retrofitting of the air conditioning system without shutting it down, eliminating the impact of construction on the customer's normal use of the air conditioning system and without affecting the safety strategies of the original control system.

Description

Technical Field

[0001] This invention relates to the field of air conditioning energy-saving technology, and in particular to a non-intrusive energy-saving control device for centralized air conditioning systems. Background Technology

[0002] The "China Building Energy Consumption Research Report (2020)" points out that in 2018, the total energy consumption of buildings throughout the entire life cycle in China was 2.147 billion tons of standard coal equivalent, accounting for 46.5% of the total national energy consumption. In particular, energy consumption during the building operation phase was 1 billion tons of standard coal equivalent, accounting for 46.6% of the building's total life cycle energy consumption and 21.7% of the national total energy consumption. Therefore, building energy conservation is of great significance to achieving my country's carbon neutrality goal. As the main part of energy consumption during the building operation phase, centralized air conditioning systems account for 40%-60% of the total building energy consumption. Therefore, improving the efficiency of air conditioning systems and reducing their energy consumption plays a crucial role in building energy conservation. Energy-saving retrofitting and optimized control of centralized air conditioning systems are important ways and key measures to achieve efficiency improvement and energy saving. During the design phase, centralized air conditioning systems are often designed based on the building's maximum air conditioning load multiplied by a certain safety factor. In actual operation, the air conditioning load usually changes over time, resulting in centralized air conditioning systems operating at low loads most of the time, leading to low operating efficiency and serious energy waste. Therefore, it is necessary to optimize and control the centralized air conditioning system in real time to solve the problem of energy waste caused by "over-powered systems."

[0003] A search of existing technologies revealed a Chinese invention patent with application number CN201610017501.X entitled "A Centralized Air Conditioning Energy-Saving Control System and Its Control Strategy," which discloses a control strategy that directly guides system regulation based on room load changes. It calculates room load fluctuations based on room temperature changes and converts them into real-time airflow, chilled water flow, and cooling water flow adjustments. The supply and return water temperature difference control mode serves as a monitoring method to maintain normal system operation. Another Chinese invention patent with application number CN200810035560.5 entitled "Model-Based Global Optimization Energy-Saving Control Method and Device for Centralized Air Conditioning Systems" discloses a method based on energy consumption models of refrigeration units, water pumps, and fans, as well as an ARMA air conditioning load prediction model. This method calculates the optimized energy-saving operating conditions of each energy-consuming device, enabling the entire system to operate at its most energy-efficient state. Chinese invention patent application CN201910446104.8, entitled "Intelligent Optimization Control Method and Device for Centralized Air Conditioning Systems Based on Big Data Cloud Platform," discloses the use of a big data platform and artificial intelligence algorithms to effectively improve the system's optimization control model and optimization calculation efficiency, providing the necessary conditions for realizing online optimization control of large-scale centralized air conditioning systems. However, the practical application of the above technology in energy-saving retrofitting of air conditioning systems requires solving the compatibility problem between the new energy-saving control system and the original building automation system (BAS). Simultaneously, it is necessary to achieve online energy-saving retrofitting of the air conditioning system without damaging the original control system.

[0004] Furthermore, in PLC controllers or controllers, analog input terminals are used for analog signals, which are typically 0-10V or 4-20mA signals. However, existing chips often experience stray currents, sudden voltage increases in the analog signal, or the inadvertent input of high-voltage AC power, such as 220V AC, when acquiring analog signals. This can damage the PLC controller or its analog-to-digital converter, and even easily lead to the failure of the entire PLC controller or controller, resulting in economic losses and project delays.

[0005] Therefore, those skilled in the art are dedicated to providing an intrusive energy-saving control device for centralized air conditioning systems, which adds a status monitoring switching device between the original water pump / fan control box and the newly added frequency converter control box, so as to realize the switching of monitoring functions of the water pump / fan operation, fault, manual / automatic, start-stop control monitoring circuit between the original control system and the new energy-saving control system. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is how to provide a non-intrusive energy-saving control device for a centralized air conditioning system.

[0007] To achieve the above objectives, this invention provides a non-intrusive energy-saving control device for a centralized air conditioning system, comprising an intelligent control platform N1 for energy-saving retrofitting, a first signal switching switch N21, a second signal switching switch N22, a data gateway N31 for the air conditioning unit for energy-saving retrofitting, a control cabinet N32 for the air conditioning chilled / hot water pump for energy-saving retrofitting, a control cabinet N33 for the cooling water pump of the air conditioning unit for energy-saving retrofitting, and a control cabinet N34 for the cooling tower for energy-saving retrofitting. The first signal switching switch N21 and the second signal switching switch N22 each include a toggle switch K, signal interface A, signal interface B, signal interface C, and a fire alarm signal interface Fs. The control cabinet N32 for the air conditioning chilled / hot water pump for energy-saving retrofitting includes a controller NC, a three-phase power switch QA1, a frequency converter controller Fre, relay switches QAC1 and QAC2. The frequency converter controller Fre includes a frequency conversion feedback interface FB, a frequency conversion adjustment interface FC, a start interface ST, a fault interface WARN, and a run interface RUN.

[0008] The air conditioning system to be upgraded mainly includes the original control platform 01, the original air conditioning unit data gateway 021, the original air conditioning chilled / hot water pump control cabinet 022, the original air conditioning unit cooling water pump control cabinet 023, the original cooling tower control cabinet 024, the air conditioning unit 04, the air conditioning chilled / hot water pump 05, the air conditioning unit cooling water pump 06, and the cooling tower 07. Among them, the original air conditioning chilled / hot water pump control cabinet 022 includes a controller 0C, a three-phase power switch QA, a relay switch QAC, and a thermal overload relay BB.

[0009] The intelligent control platform N1 for energy-saving renovation is connected to signal interface B in the first signal switching switch N21. The original control platform 01 is connected to signal interface A in the first signal switching switch N21. Signal interface C in the first signal switching switch N21 is connected to signal interface C in the second signal switching switch N22. Signal interfaces B in the second signal switching switch N22 are respectively connected to the data gateway N31 for the energy-saving renovation air conditioning unit, the control cabinet N32 for the energy-saving renovation air conditioning chilled / hot water pump, the control cabinet N33 for the energy-saving renovation air conditioning unit cooling water pump, and the control cabinet N34 for the energy-saving renovation cooling tower. Signal interfaces A in the second signal switching switch N22 are respectively connected to the original air conditioning unit data gateway 021, the original air conditioning unit data gateway N31, the original air conditioning unit data gateway N32, the original air conditioning unit data gateway N33, the original air conditioning unit data gateway N34 ... The cooling / hot water pump control cabinet 022, the original air conditioning unit cooling water pump control cabinet 023, and the original cooling tower control cabinet 024 are all connected. The built-in controller of the air conditioning unit 04 is connected to the data gateway N31 of the air conditioning unit for energy-saving renovation and the data gateway 021 of the original air conditioning unit. The motors of the air conditioning cooling / hot water pump 05 are connected to the air conditioning cooling / hot water pump control cabinet N32 for energy-saving renovation and the original air conditioning cooling / hot water pump control cabinet 022. The motors of the air conditioning unit cooling water pump 06 are connected to the air conditioning cooling water pump control cabinet N33 for energy-saving renovation and the original cooling water pump control cabinet 023. The motors of the cooling tower 07 are connected to the cooling tower control cabinet N34 for energy-saving renovation and the original cooling tower control cabinet 024.

[0010] The connection relationship between the air conditioner chilled / hot water pump control cabinet N32 for energy-saving renovation and the original air conditioner chilled / hot water pump control cabinet 021 is as follows: Three-phase power switch QA1 is connected to the three-phase power input port of the inverter Fre. The three-phase power output port of the inverter Fre is connected to the water pump / fan motor M via relay switch QAC1. The signal interface of the controller NC is connected to relay switches QAC1 and QAC2, and to each signal interface of the inverter controller Fre (including the frequency conversion feedback interface FB, frequency conversion regulation interface FC, start interface ST, fault interface WARN, and run interface RUN). Three-phase power switch QA is connected to the thermal overload relay BB via relay switch QAC. The thermal overload relay BB is connected to the motor M of the air conditioner chilled / hot water pump 05 via relay switch QAC2. The signal interface of the controller OC is connected to relay switch QAC. The connection relationships between the cooling water pump control cabinet N33 of the air conditioning unit used for energy-saving renovation and the original cooling water pump control cabinet 023 of the air conditioning unit, as well as the connection relationships between the cooling tower control cabinet N34 of the energy-saving renovation and the original cooling tower control cabinet 024, are consistent with the above.

[0011] When the intelligent control platform N1 for energy-saving renovation needs to perform energy-saving control tasks normally, the three-phase power switch QA in the original air conditioning chilled / hot water pump control cabinet 022 is opened, and the three-phase power switch QA1 in the air conditioning chilled / hot water pump control cabinet N32 for energy-saving renovation is closed. The toggle switch K in the first signal switching switch N21 and the second signal switching switch N22 is switched to the signal interface C, so that the signal interfaces B and C in the first signal switching switch N21 and the second signal switching switch N22 are connected, and the signal interfaces A and C are disconnected. The controller OC in the original air conditioning chilled / hot water pump control cabinet 022 and the controller NC in the air conditioning chilled / hot water pump control cabinet N32 for energy-saving renovation send instructions to make the relay switches QAC and QAC2 open and the relay switch QAC1 close, so that the frequency converter Fre and the motor M are connected.

[0012] In an emergency, such as when signal interface C in the first signal switch N21 and fire alarm signal interface Fs in the second signal switch N22 receive a fire alarm signal, the three-phase switch QA in the original air conditioning chilled / hot water pump control cabinet 022 closes, and the three-phase switch QA1 in the energy-saving retrofit air conditioning chilled / hot water pump control cabinet N32 opens. The toggle switch K in the first signal switch N21 and the second signal switch N22 automatically switches to signal interface A, causing signal interfaces B and C in the first signal switch N21 and the second signal switch N22 to open, and signal interfaces A and C to connect. The controller OC in the original air conditioning chilled / hot water pump control cabinet 022 and the controller NC in the energy-saving retrofit air conditioning chilled / hot water pump control cabinet N32 issue commands to close relay switches QAC and QAC2, and open relay switch QAC1. At this point, the original control platform 01 resumes control over the main power equipment of the air conditioning system, including air conditioning unit 04, air conditioning chilled / hot water pump 05, air conditioning unit cooling water pump 06, cooling tower 07, and smoke extraction system equipment. The operation methods of the energy-saving retrofit air conditioning unit cooling water pump control cabinet N33, the energy-saving retrofit cooling tower control cabinet N34, the original air conditioning unit cooling water pump control cabinet 023, and the original cooling tower control cabinet 024 are the same as described above.

[0013] This invention also provides a multi-type signal differential input protection circuit. The input signal type (0-10V or 4-20mA) is selected by shorting pins. An overload protection device prevents excessive voltage from accidentally entering the analog input terminal, which could lead to voltage rise at the converter input terminal and damage to the analog-to-digital converter. A voltage conversion device obtains the normal operating voltage values ​​for the operational amplifier and analog-to-digital converter. A signal processing device processes the input analog signal to obtain a stable and effective analog signal. A filtering device eliminates stray currents such as AC current in the analog signal. Furthermore, this technical solution utilizes a surge protection device to guide any AC current accidentally entering the analog signal input terminal to ground, protecting the operational amplifier and analog-to-digital converter. This prevents damage to the operational amplifier, analog-to-digital converter, and PLC controller, improving the safety and reliability of the PLC controller and thus avoiding economic losses and project delays.

[0014] The present invention provides a multi-type signal differential input protection circuit, including an analog signal input terminal, a signal conversion device, a voltage conversion device, an overload protection device, a surge protection device, a filtering device, and a signal processing device.

[0015] The analog signal input terminal receives the analog signal, which passes through the load protection device, surge protection device, filtering device and signal processing device in sequence, and is output to the signal conversion device; the analog-to-digital converter in the signal conversion device receives the analog signal processed by the signal processing device.

[0016] In the above scheme, the analog signal input terminal includes a 3-pin header X1, a 2-pin header P1, resistors R1 and R4; one end of resistor R1 is connected to the 5V voltage terminal, and the other end is connected to pin 3 of header X1; one end of resistor R4 is connected to pin 1 of header X1, and the other end is connected to the negative terminal of the differential input signal; pin 2 of the 3-pin header is connected to one end of the overload protection device; pin 1 of the 2-pin header P1 is connected to the negative terminal UI1- of the analog input terminal, and pin 2 is grounded.

[0017] In the above scheme, the overload protection device includes a self-resetting fuse F1. One end of F1 is connected to pin 2 of the 3-pin header X1 in the analog input terminal, and the other end is connected to the positive terminal UI1+ of the analog input terminal.

[0018] In the above scheme, the voltage conversion device includes transistor VT1, voltage reference chip VT2, inductor L2, resistors R5, R6, R7, and R10, and capacitors C6 and C7; one end of resistor R5 is connected to DC24V, and the other end is connected to the collector of VT1; one end of resistor R6 is connected to DC24V, and the other end is connected to the base of VT1; one end of resistor R7 is connected to the emitter of VT1, and the other end is connected to pin 1 of VT2; one end of resistor R10 is connected to pin 1 of VT2, and the other end is connected to pin 3 of VT2; capacitors C6 and C7 and inductor L2 together form a Π-type filter.

[0019] In the above scheme, the surge protection device includes three transient suppression diodes, also known as TVS diodes; one of the TVS diodes is connected to the positive and negative terminals of the analog input signal respectively; the other two TVS diodes are connected to the positive and negative terminals of the analog input signal respectively at one end, and grounded at the other end.

[0020] In the above scheme, the filtering device includes inductors L1 and L3 and capacitors C3 and C4; one end of L1 is connected to the negative terminal UI1- of the analog signal input terminal, and the other end is connected to C3, and the other end of C3 is connected to ground; one end of L3 is connected to the positive terminal UI1+ of the analog signal input terminal, and the other end is connected to C4, and the other end of C4 is connected to ground.

[0021] In the above scheme, the signal processing device includes an operational amplifier N1A, capacitors C1 and C2, and resistors R2, R3, R8, and R9. One end of R2 is connected to the filter device at the negative terminal UI1- of the analog input, and the other end is connected to the negative input of the operational amplifier N1A. One end of R3 is connected to R2, and the other end is connected to the output terminal of the operational amplifier N1A. One end of R8 is connected to the filter device at the positive terminal UI1+ of the analog input, and the other end is connected to the positive input of the operational amplifier N1A. One end of R9 is connected to R8, and the other end is grounded. Capacitor C1 is connected in parallel to R3. One end of capacitor C2 is connected to 5V, and the other end is grounded.

[0022] In the above scheme, the signal conversion device includes an analog-to-digital converter D1 and a capacitor C5. One end of the capacitor C5 is connected to 5V and the other end is grounded. Pin 4 of the analog-to-digital converter receives the analog signal AD1 output by the signal conversion device, and then sends out the converted digital signal through SPI communication.

[0023] The non-intrusive energy-saving control device for centralized air conditioning systems provided by this invention has a built-in Modbus RTU to TCP protocol conversion gateway, which can upload data collected from the RS485 bus to the PLC controller and other corresponding devices via the TCP protocol.

[0024] The hardware circuit of the Modbus RTU to TCP protocol data gateway provided by this invention includes an Ethernet chip device, an RJ45 network port device, an MCU device, and an RS485 device.

[0025] In the above scheme, the Ethernet chip U1 in the Ethernet chip device is connected to the FSMC bus of the MCU device via a 16-bit data bus; the chip select terminal of the Ethernet chip U1 is controlled by the FSMC_NE2 of the MCU device; and the CMD is controlled by the FSMC_A7 of the MCU device.

[0026] In the above scheme, the RJ45 network port device is connected to the Ethernet device via TP_TX+, TP_TX- and TP_RX+, TP_RX- signals for data transmission and reception; the RJ45 network port device is connected to the Ethernet device via LEDA and LEDB signals to control the on / off state of the indicator lights on the RJ45 interface J1, thereby determining whether the communication is normal; in addition, the selected RJ45 interface U1 is an RJ45 interface with a built-in network transformer, which can enhance the signal, making its transmission distance longer, while isolating the chip end from the outside, greatly enhancing the anti-interference capability, and also enhancing the protection of the internal chip;

[0027] In the above scheme, the MCU device internally consists of a 32-bit microcontroller chip and corresponding peripheral circuits. The microcontroller chip has a main frequency of 72MHz, contains 512K of Flash and 64K of SRAM, and supports the FSMC bus. The MCU device transmits data to the Ethernet device through the 16-bit data bus FSMC, and controls the chip select, CMD, reset, and other functions of the Ethernet chip U1 in the Ethernet device through signals such as FSMC_NE2, FSMC_A7, and DM9000_RST. At the same time, the MCU device is connected to the RS485 device through RX and TX signals for communication and data exchange.

[0028] In the above scheme, the RS485 device is connected to the MCU device through RX and TX signals for communication and data interaction; at the same time, the RS485 device adopts opto-isolation technology, using optocouplers N2 and N3 to opto-isolate from the MCU device, which can effectively prevent externally acquired 485 stray signals from interfering with the MCU and enhance the circuit's anti-interference capability.

[0029] The present invention has at least the following beneficial technical effects:

[0030] This invention eliminates the need to modify the existing building control system during energy-saving retrofits. The protocol conversion gateway supports conversion between different protocols, enabling interconnection between networks with different protocols and communication between heterogeneous devices, thus reducing the workload and cost of energy-saving retrofits. This invention allows for online energy-saving retrofits without shutting down the air conditioning system, eliminating the impact of construction on the customer's normal use of the air conditioning system and not affecting the safety strategies of the original control system. In the event of an accident or fire, the switching device switches the monitoring line back to the original control system, executing the original system's civil defense safety controls. Furthermore, the RJ45 network port with a network transformer and optocoupler used in the gateway significantly improve the circuit's anti-interference capability and stability. This invention is suitable for widespread application in existing intelligent optimization and energy-saving control technologies for air conditioning systems, possessing significant social and economic benefits.

[0031] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the non-intrusive energy-saving control device for a centralized air conditioning system according to the present invention;

[0033] Figure 2 This is a schematic diagram of the connection structure between the air conditioning chilled / hot water pump control cabinet and the original air conditioning chilled / hot water pump control cabinet of the non-intrusive energy-saving control device for centralized air conditioning systems of the present invention.

[0034] Figure 3 This is a schematic diagram of the multi-signal type differential input protection circuit of the present invention;

[0035] Figure 4 This is a hardware circuit diagram of the Modbus RTU to TCP protocol data gateway of the present invention. Detailed Implementation

[0036] The preferred embodiments of the present invention are described below to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0037] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0038] like Figure 1The non-intrusive energy-saving control device for the centralized air conditioning system shown is as follows: N1 is the intelligent control platform for energy-saving renovation; N21 is the first signal switching switch; N22 is the second signal switching switch; N31 is the data gateway for the air conditioning unit for energy-saving renovation; N32 is the control cabinet for the chilled / hot water pump of the air conditioning unit for energy-saving renovation; N33 is the control cabinet for the cooling water pump of the air conditioning unit for energy-saving renovation; N34 is the control cabinet for the cooling tower for energy-saving renovation; 01 is the original control platform; 021 is the original data gateway for the air conditioning unit; 022 is the original control cabinet for the chilled / hot water pump of the air conditioning unit; 023 is the original control cabinet for the cooling water pump of the air conditioning unit; 024 is the original control cabinet for the cooling tower; 04 is the air conditioning unit; 05 is the chilled / hot water pump of the air conditioning unit; 06 is the cooling water pump of the air conditioning unit; and 07 is the cooling tower. Both the first signal switching switch N21 and the second signal switching switch N22 include a toggle switch K, signal interface A, signal interface B, signal interface C, and a fire alarm signal interface Fs. The intelligent control platform N1 for energy-saving renovation is connected to signal interface B in the first signal switching switch N21. The original control platform 01 is connected to signal interface A in the first signal switching switch N21. Signal interface C in the first signal switching switch N21 is connected to signal interface C in the second signal switching switch N22. Signal interfaces B in the second signal switching switch N22 are respectively connected to the data gateway N31, the air conditioning chilled / hot water pump control cabinet N32, the cooling water pump control cabinet N33, and the cooling tower control cabinet N34 for the energy-saving renovation air conditioning unit. Signal interfaces A in the second signal switching switch N22 are respectively connected to the original air conditioning unit data gateway 021, the original air conditioning unit data gateway N31, the original air conditioning unit data gateway N32, the original air conditioning unit data gateway N33, the original air conditioning unit data gateway N34, and the original air conditioning unit data gateway N35. The cooling / hot water pump control cabinet 022, the existing air conditioning unit cooling water pump control cabinet 023, and the existing cooling tower control cabinet 024 are connected. The built-in controller of the air conditioning unit 04 is connected to the data gateway N31 of the air conditioning unit for energy-saving renovation and the data gateway 021 of the existing air conditioning unit. The motors of the air conditioning cooling / hot water pump 05 are connected to the air conditioning cooling / hot water pump control cabinet N32 for energy-saving renovation and the existing air conditioning cooling / hot water pump control cabinet 022. The motors of the air conditioning unit cooling water pump 06 are connected to the air conditioning cooling water pump control cabinet N33 for energy-saving renovation and the existing cooling water pump control cabinet 023. The motors of the cooling tower 07 are connected to the cooling tower control cabinet N34 for energy-saving renovation and the existing cooling tower control cabinet 024.

[0039] like Figure 2As shown, the air conditioning chilled / hot water pump control cabinet N32 for energy-saving renovation includes a controller NC, a three-phase power switch QA1, a frequency converter Fre, relay switches QAC1 and QAC2; among which, the frequency converter Fre includes a frequency conversion feedback interface FB, a frequency conversion regulation interface FC, a start interface ST, a fault interface WARN, and a run interface RUN. The original air conditioning chilled / hot water pump control cabinet 022 includes a controller OC, a three-phase power switch QA, relay switches QAC, and a thermal overload relay BB; M is the motor of the air conditioning chilled / hot water pump 05. The three-phase power switch QA1 is connected to the three-phase power input port of the frequency converter Fre, and the three-phase power output port of the frequency converter Fre is connected to the water pump / fan motor M through the relay switch QAC1. The signal interface of the controller NC is connected to the relay switches QAC1, QAC2, and the signal interface of the frequency converter Fre, respectively. The three-phase switch QA is connected to the thermal overload relay BB via relay switch QAC. The thermal overload relay BB is connected to the motor M of the air conditioner chilled / hot water pump 05 via relay switch QAC2. The signal interface of the controller 0C is connected to relay switch QAC. The connection relationships between the cooling water pump control cabinet N33 of the energy-saving retrofit air conditioning unit and the original air conditioning unit cooling water pump control cabinet 023, as well as the connection relationships between the cooling tower control cabinet N34 of the energy-saving retrofit and the original cooling tower control cabinet 024, are all related to... Figure 2 Consistent.

[0040] When the intelligent control platform N1 for energy-saving renovation needs to perform energy-saving control tasks normally, the three-phase power switch QA in the original air conditioning chilled / hot water pump control cabinet 022 is opened, and the three-phase power switch QA1 in the air conditioning chilled / hot water pump control cabinet N32 for energy-saving renovation is closed. The toggle switch K in the first signal switching switch N21 and the second signal switching switch N22 is switched to the signal interface C, so that the signal interfaces B and C in the first signal switching switch N21 and the second signal switching switch N22 are connected, and the signal interfaces A and C are disconnected. The controller OC in the original air conditioning chilled / hot water pump control cabinet 022 and the controller NC in the air conditioning chilled / hot water pump control cabinet N32 for energy-saving renovation send instructions to make the relay switches QAC and QAC2 open and the relay switch QAC1 close, so that the frequency converter Fre and the motor M are connected.

[0041] In an emergency, such as when signal interface C in the first signal switch N21 and fire alarm signal interface Fs in the second signal switch N22 receive a fire alarm signal, the three-phase switch QA in the original air conditioning chilled / hot water pump control cabinet 022 closes, and the three-phase switch QA1 in the energy-saving retrofit air conditioning chilled / hot water pump control cabinet N32 opens. The toggle switch K in the first signal switch N21 and the second signal switch N22 automatically switches to signal interface A, causing signal interfaces B and C in the first signal switch N21 and the second signal switch N22 to open, and signal interfaces A and C to connect. The controller OC in the original air conditioning chilled / hot water pump control cabinet 022 and the controller NC in the energy-saving retrofit air conditioning chilled / hot water pump control cabinet N32 issue commands to close relay switches QAC and QAC2, and open relay switch QAC1. At this time, the original control platform 01 resumes control over the main power equipment of the air conditioning system, including air conditioning unit 04, air conditioning chilled / hot water pump 05, air conditioning unit cooling water pump 06, cooling tower 07, and smoke prevention and exhaust system equipment.

[0042] The operation methods of the air conditioning unit cooling water pump control cabinet N33, the cooling tower control cabinet N34 for energy-saving renovation, the existing air conditioning unit cooling water pump control cabinet 023, and the existing cooling tower control cabinet 024 are the same as those described above.

[0043] like Figure 3 As shown, this embodiment is a multi-signal type differential input protection circuit, including analog input terminals 1 and 2, an overload protection device 3, a voltage conversion device 4, a surge protection device 5, filtering devices 6 and 7, a signal processing device 8, and a signal conversion device 9. Analog input terminals 1 and 2 receive analog signals, which pass sequentially through the overload protection device 3, the surge protection device 5, the filtering devices 6 and 7, and the signal processing device 8, before being output to the signal conversion device 9. The analog-to-digital converter in the signal conversion device 9 receives the analog signal processed by the signal processing device.

[0044] The input signal type is selected by shorting the 3-pin header in the analog input terminal. The overload protection device 3 is used to prevent excessive voltage from being accidentally applied to the analog input terminals 1 and 2, which could cause the voltage of the signal conversion device 9 to rise and damage the analog-to-digital converter. The filtering devices 6 and 7 are used to eliminate stray currents such as AC in the analog signal. The signal processing device 8 is used to process the input analog signal, thereby obtaining a stable and effective analog signal for input to the signal conversion device 9.

[0045] In the surge protection device 5 of the protection circuit, one end of each of the two bidirectional TVS diodes is connected to the positive and negative terminals of the analog input terminals respectively, and the other end is grounded. The other TVS diode is directly connected to the two filter devices. When AC power, such as 220V AC, is accidentally introduced into analog input terminals 1 and 2, the surge protection device 5 will quickly form a circuit and conduct the AC power to ground. Diodes VP1, VP2, and VP3 are bidirectional transient suppression diodes. Among them, bidirectional transient suppression diodes have advantages such as fast response time, high transient power, low leakage current, low breakdown voltage deviation, easy control of clamping voltage, no damage limit, and small size. They can quickly conduct AC power that has been accidentally introduced into analog input terminals 1 and 2 to ground, protecting the safety of the analog-to-digital converter.

[0046] The overload protection device 3 includes a fuse F1, which is a self-resetting fuse. The self-resetting fuse has the characteristics of fast resistance change speed, short recovery time and impact resistance. It can disconnect in time when excessive voltage is accidentally applied to the analog input terminals 1 and 2 to protect the analog-to-digital converter and operational amplifier.

[0047] The voltage conversion device 4 includes a transistor VT1, a voltage reference chip VT2, an inductor L2, resistors R5, R6, R7, and R10, and capacitors C6 and C7. One end of resistor R5 is connected to DC24V, and the other end is connected to the collector of VT1. One end of resistor R6 is connected to DC24V, and the other end is connected to the base of VT1. One end of resistor R7 is connected to the emitter of VT1, and the other end is connected to pin 1 of VT2. One end of resistor R10 is connected to pin 1 of VT2, and the other end is connected to pin 3 of VT2. Capacitors C6 and C7 and inductor L2 together form a Π-type filter. The voltage reference chip VT2 is used to control the voltage output, obtaining a stable 5V voltage from DC24V to power the operational amplifier and analog-to-digital converter.

[0048] Filtering devices 6 and 7 include inductors L1 and L3 and capacitors C3 and C4; one end of L1 is connected to the negative terminal UI1- of the analog input terminal, and the other end is connected to C3, and the other end of C3 is connected to ground; one end of L3 is connected to the positive terminal UI1+ of the analog input terminal, and the other end is connected to C4, and the other end of C4 is connected to ground; L1, C3 and L2, C4 form two LC filters, which can reduce signal loss in the circuit and block and filter stray currents such as AC current in the analog signal. At the same time, the stray current can also be grounded through capacitor C1.

[0049] The signal processing device 8 includes an operational amplifier N1A, capacitors C1 and C2, and resistors R2, R3, R8, and R9. One end of R2 is connected to the filter device at the negative terminal UI1- of the analog input, and the other end is connected to the negative input of the operational amplifier N1A. One end of R3 is connected to R2, and the other end is connected to the output terminal of the operational amplifier N1A. One end of R8 is connected to the filter device at the positive terminal UI1+ of the analog input, and the other end is connected to the positive input of the operational amplifier N1A. One end of R9 is connected to R8, and the other end is grounded. Capacitor C1 is connected in parallel to R3. One end of capacitor C2 is connected to 5V, and the other end is grounded. By using the operational amplifier, the analog signal input to the analog-to-digital converter can be stably and effectively controlled, and corresponding common-mode interference in the signal can be blocked.

[0050] The signal conversion device 9 includes an analog-to-digital converter D1 and a capacitor C5. One end of the capacitor C5 is connected to 5V and the other end is grounded. Pin 4 of the analog-to-digital converter receives the analog signal AD1 output by the signal conversion device and then sends out the converted digital signal through SPI communication.

[0051] like Figure 4 The hardware circuit diagram of the Modbus RTU to TCP protocol data gateway shown includes an Ethernet chip device 10, an RJ45 network port device 11, an MCU device 12, and an RS485 device 13. Its working principle is as follows: the RS485 device communicates with the corresponding device via the RS485 bus, collects the data signals from the corresponding device, and then sends the collected data signals to the MCU device via TX and RX signals. The MCU device internally parses and processes the received data and then sends it to the Ethernet device via the 16-bit interface bus FSMC. The Ethernet device buffers and processes the received data, and then sends the data to the RJ45 device via TP_TX+, TP_TX- and TP_RX+, TP_RX- signals. The RJ45 device then transmits the data to the connected device via a network cable.

[0052] The Ethernet chip U1 in the Ethernet chip device is connected to the FSMC bus of the MCU device via a 16-bit data bus; the chip select terminal of the Ethernet chip U1 is controlled by the FSMC_NE2 of the MCU device; and the CMD is controlled by the FSMC_A7 of the MCU device.

[0053] The RJ45 network port device connects to the Ethernet device via TP_TX+, TP_TX- and TP_RX+, TP_RX- signals for data transmission and reception. The RJ45 network port device also connects to the Ethernet device via LEDA and LEDB signals, controlling the indicator lights on RJ45 interface J1 to determine if communication is normal. Furthermore, the selected RJ45 interface U1, with its built-in network transformer, enhances the signal, extending the transmission distance. It also isolates the chip from external interference, significantly improving anti-interference capabilities and enhancing protection for the internal chip.

[0054] The MCU device contains a 32-bit microcontroller chip and corresponding peripheral circuits. The microcontroller chip has a main frequency of 72MHz, contains 512K of Flash and 64K of SRAM, and supports the FSMC bus. The MCU device transmits data to the Ethernet device through the 16-bit data bus FSMC, and controls the chip select, CMD, reset, and other functions of the Ethernet chip U1 in the Ethernet device through signals such as FSMC_NE2, FSMC_A7, and DM9000_RST. At the same time, the MCU device is connected to the RS485 device through RX and TX signals for communication and data exchange.

[0055] The RS485 device connects to the MCU device via RX and TX signals for communication and data exchange. At the same time, the RS485 device adopts opto-isolation technology, using optocouplers N2 and N3 to opto-isolate from the MCU device, which can effectively prevent externally acquired 485 stray signals from interfering with the MCU and enhance the circuit's anti-interference capability.

[0056] The specific software processing procedure involves iterating through and querying the contents of the "Operating Status" register in all built-in chiller unit protocols. If the return value is correct, the chiller communication protocol is automatically matched, avoiding tedious manual selection, improving the recognition rate, and lowering the application threshold.

[0057] The following is a specific embodiment of a matching program for a refrigeration unit protocol, including some of the protocol content:

[0058] PC-DBY-A Centrifugal Refrigeration Unit Microcomputer Control System

[0059] Communication interface protocol

[0060] I. Interface Type

[0061] The microcomputer control system of the centrifugal chiller provides an RS-485 interface. The interface communication parameters are:

[0062] Baud Rate: 9600

[0063] Data Bits: 8

[0064] Parity:NONE

[0065] Stop Bits: 1

[0066] II. Interface Protocol

[0067] MODBUS (RTU)

[0068] III. Lower-level machine address

[0069] 1. Lower-level machine status address (bit address)

[0070] 1.2 Digital Input Status

[0071]

[0072] The program contains a built-in list of hundreds of communication protocols, including parameters such as baud rate and "host running" register information. It reads each protocol one by one until a correct return frame is matched, and then sends the data frame. The program is as follows:

[0073]

[0074]

[0075] If no frame is returned after three reads, proceed with the next protocol content read until a correct frame is returned.

[0076] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, those skilled in the art can obtain the following results based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology.

Claims

1. A non-intrusive energy-saving control device for a centralized air conditioning system, characterized in that, It includes an intelligent control platform (N1), a first signal switching switch (N21), a second signal switching switch (N22), a data gateway for the air conditioning unit used for energy-saving renovation (N31), a control cabinet for the chilled / hot water pump of the air conditioning unit used for energy-saving renovation (N32), a control cabinet for the cooling water pump of the air conditioning unit used for energy-saving renovation (N33), and a control cabinet for the cooling tower used for energy-saving renovation (N34). The energy-saving retrofit intelligent control platform (N1) is connected to the signal interface B of the first signal switching switch (N21). The signal interface A of the first signal switching switch (N21) is connected to the original control platform (01). The signal interface C of the first signal switching switch (N21) is connected to the signal interface C of the second signal switching switch (N22). The signal interface B of the second signal switching switch (N22) is connected to the data gateway (N31) of the energy-saving retrofit air conditioning unit, the control cabinet (N32) of the energy-saving retrofit air conditioning chilled / hot water pump, the control cabinet (N33) of the energy-saving retrofit air conditioning unit cooling water pump, and the control cabinet (N34) of the energy-saving retrofit cooling tower. The signal interface A of the second signal switching switch (N22) is connected to the original air conditioning unit data gateway (021) and the original air conditioning unit cooling tower control cabinet (01). The cooling / hot water pump control cabinet (022), the original air conditioning unit cooling water pump control cabinet (023), and the original cooling tower control cabinet (024) are connected. The controller of the air conditioning unit (04) is connected to the data gateway (N31) of the air conditioning unit for energy-saving renovation and the data gateway (021) of the original air conditioning unit. The motor of the air conditioning cooling / hot water pump (05) is connected to the control cabinet (N32) of the air conditioning cooling / hot water pump for energy-saving renovation and the control cabinet (022) of the original air conditioning cooling / hot water pump. The motor of the air conditioning unit cooling water pump (06) is connected to the control cabinet (N33) of the air conditioning unit for energy-saving renovation and the control cabinet (023) of the original cooling water pump. The motor of the cooling tower (07) is connected to the control cabinet (N34) of the cooling tower for energy-saving renovation and the control cabinet (024) of the original cooling tower.

2. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 1, characterized in that, The first signal switching switch (N21) and the second signal switching switch (N22) also include a toggle switch K and a fire alarm signal interface Fs.

3. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 1, characterized in that, The energy-saving retrofit air conditioning chilled / hot water pump control cabinet (N32) includes a controller NC, a three-phase power switch QA1, a frequency converter Fre, a relay switch QAC1, and a relay switch QAC2. The frequency converter Fre includes a frequency conversion feedback interface FB, a frequency conversion adjustment interface FC, a start interface ST, a fault interface WARN, and a run interface RUN. The three-phase power switch QA1 is connected to the three-phase power input port of the frequency converter Fre, and the three-phase power output port of the frequency converter Fre is connected to the motor M of the water pump / fan through the relay switch QAC1. The signal interface of the controller NC is connected to the signal interfaces of the relay switch QAC1, the relay switch QAC2, and the frequency converter Fre, respectively.

4. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 3, characterized in that, The controller NC includes multiple types of signal differential input protection circuits. The protection circuits include an analog signal input terminal, a signal conversion device, a voltage conversion device, an overload protection device, a surge protection device, a filtering device, and a signal processing device. The analog signal input terminal receives analog signals, which are sequentially passed through the overload protection device, the surge protection device, the filtering device, and the signal processing device, and then output to the signal conversion device. The analog-to-digital converter in the signal conversion device receives the analog signal processed by the signal processing device.

5. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 4, characterized in that, The analog signal input terminal includes a 3-pin header X1, a 2-pin header P1, resistors R1 and R4; one end of resistor R1 is connected to a 5V voltage terminal, and the other end is connected to pin 3 of header X1; one end of resistor R4 is connected to pin 1 of header X1, and the other end is connected to the negative terminal of the differential input signal; pin 2 of the 3-pin header is connected to one end of the overload protection device; pin 1 of the 2-pin header P1 is connected to the negative terminal UI1- of the analog signal input terminal, and pin 2 is grounded.

6. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 5, characterized in that, The voltage conversion device includes a transistor VT1, a voltage reference chip VT2, an inductor L2, resistors R5, R6, R7, and R10, and capacitors C6 and C7. One end of resistor R5 is connected to DC24V, and the other end is connected to the collector of VT1. One end of resistor R6 is connected to DC24V, and the other end is connected to the base of VT1. One end of resistor R7 is connected to the emitter of VT1, and the other end is connected to pin 1 of VT2. One end of resistor R10 is connected to pin 1 of VT2, and the other end is connected to pin 3 of VT2. Capacitors C6 and C7 and inductor L2 together form a Π-type filter.

7. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 6, characterized in that, The surge protection device includes three TVS diodes; one of the TVS diodes is connected to the positive and negative terminals of the analog signal input terminal respectively; the other two TVS diodes are connected to the positive and negative terminals of the analog signal input terminal respectively at one end, and grounded at the other end.

8. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 7, characterized in that, The signal processing device includes an operational amplifier N1A, capacitors C1 and C2, and resistors R2, R3, R8, and R9. One end of resistor R2 is connected to the filter device at the negative terminal UI1- of the analog signal input, and the other end is connected to the negative input of operational amplifier N1A. One end of resistor R3 is connected to R2, and the other end is connected to the output terminal of operational amplifier N1A. One end of resistor R8 is connected to the filter device at the positive terminal UI1+ of the analog signal input, and the other end is connected to the positive input of operational amplifier N1A. One end of resistor R9 is connected to R8, and the other end is grounded. Capacitor C1 is connected in parallel to R3. One end of capacitor C2 is connected to 5V, and the other end is grounded.

9. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 1, characterized in that, It also includes the hardware circuit of a Modbus RTU to TCP protocol data gateway, which includes an Ethernet chip device, an RJ45 network port device, an MCU device, and an RS485 device. The RS485 device uploads the collected data to the MCU device through the serial bus TX and RX. The MCU device sends the data to the Ethernet chip device through the FSMC bus, and then the Ethernet chip device uploads the data through the RJ45 network port device.

10. The non-intrusive energy-saving control device for a centralized air conditioning system as described in claim 9, characterized in that, The Ethernet chip device includes an Ethernet chip U1, a diode D2, a crystal oscillator Y1, resistors R11, R12, R13, R14, R15, R20, and R21, and capacitors C10, C11, C12, C13, C15, and C16; the RJ45 network port device includes an RJ45 network port J1, resistors R26, R27, R28, and R29, and capacitors C17, C18, and C19; the RS485 device includes optocouplers N2 and N3, an RS485 transceiver chip D3, a transistor V1, a bidirectional TVS diode VP4, resistors R16, R17, R18, R19, R22, R23, R24, and R25, and capacitors C8, C9, and C14.

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