DDC control box master control system

Abstract

The application relates to a DDC control box master control system in the technical field of DDC control boxes, characterized in that the DDC control box master control system comprises a DDC control box, a master microprocessor, a sensor network, an A / D conversion module, a D / A conversion module and an actuator system; the master microprocessor, the A / D and D / A modules are integrated on a pre-wired PCB, and a flip wiring structure is adopted, so that the deployment of field connection and external wiring and fixed internal wiring is realized; the master end runs an IEC 61131-3 standard programmable runtime, fuses an incremental PID, a feedforward and a fuzzy self-tuning algorithm, so that the air supply temperature fluctuation control is within + / -0.3 DEG C, and online downloading and remote debugging are supported; a field-region-central three-level distributed system is constructed, local closed-loop control is still maintained when the central network is interrupted, an enthalpy energy-saving strategy and a double-threshold anti-freezing interlock are matched, the control precision, the energy-saving rate and the system safety are considered, and the problems of traditional DDC box wiring confusion, algorithm solidification, protocol closure and single machine failure and loss of control are solved.

Description

Technical Field

[0001] This invention relates to the field of DDC control box technology, specifically a DDC control box main control system. Background Technology

[0002] The DDC control box is a direct digital controller and the core control unit of an automation system (BAS / BMS). It is an intelligent control unit that integrates the controller, terminal block, power supply, communication module, and protection devices. However, existing DDC control box main control systems generally have the following shortcomings: 1. In terms of hardware, it uses discrete terminals and field wiring, which is complicated to construct, has a high error rate, and a long debugging cycle; in terms of control, it only supports a simple PI algorithm with fixed parameters, and the supply air temperature fluctuates by more than ±1.5℃, which is difficult to meet the requirements of constant temperature and humidity scenarios; in terms of software, the programming language is proprietary to the manufacturer and does not support online download and version management, and operation and maintenance heavily rely on on-site operation. 2. In terms of communication, most systems employ closed protocols and a two-level star topology, leading to complete loss of control in the event of a central station or bus failure. Regarding energy efficiency, they lack enthalpy calculation and fresh air ratio optimization, resulting in significant energy waste during transitional seasons. In terms of environmental adaptability, the enclosure has low protection levels, a narrow operating temperature range, and only a single-threshold alarm for freeze protection, posing a risk of coil freezing and cracking. Therefore, there is an urgent need for a DDC control box main control system with high integration, precise control, open programming, three-level disaster recovery, quantifiable energy savings, and strong environmental adaptability. To this end, the inventors have proposed a DDC control box main control system to address the aforementioned technical problems. Summary of the Invention

[0003] To overcome the shortcomings mentioned above, the invention aims to provide a technical solution that can solve the above problems.

[0004] A DDC control box main control system, characterized in that it includes: a DDC control box, a main control microprocessor, a sensor network, an A / D conversion module, a D / A conversion module, and an actuator system; The main control microprocessor is located inside the DDC control box. The sensor network is connected to the A / D conversion module. The A / D conversion module is connected to the main control microprocessor. The main control microprocessor is connected to the D / A conversion module. The D / A conversion module is connected to the actuator system. The sensor network is used to collect analog signals of the building environment and equipment status. The A / D conversion module is used to convert the analog signals into digital signals and transmit them to the main control microprocessor. The main control microprocessor is used to perform calculations on the digital signals according to preset control logic and generate control instructions. The D / A conversion module is used to convert the control instructions into drive signals to control the actuator system.

[0005] Furthermore, the DDC control box integrates a wiring module and a PCB circuit board inside its enclosure, and the main control microprocessor, the A / D conversion module, and the D / A conversion module are all integrated on the PCB circuit board; The wiring module adopts a flip-type wiring structure. The power supply terminals of the sensor network and the external devices of the actuator system are all connected through the wiring module, and the power lines and network lines inside the DDC control box are pre-connected.

[0006] Furthermore, the main control microprocessor adopts an ARM Cortex-M series microprocessor or an Intel Atom-level low-power SoC chip. The main control microprocessor runs programmable control software based on the IEC 61131-3 standard, which supports online download, version management and remote debugging.

[0007] Furthermore, the sensor network includes at least one of a temperature sensor, a humidity sensor, a pressure sensor, a CO2 concentration sensor, a differential pressure sensor, a flow sensor, and an air quality sensor; The temperature sensor is a platinum resistance thermometer (PT100) or an NTC thermistor, the humidity sensor is a capacitive polymer thin film sensor, and the CO2 concentration sensor is an NDIR non-dispersive infrared sensor.

[0008] Furthermore, the actuator system includes switching actuators, regulating actuators, and intelligent actuators; The regulating actuator includes a three-way electric water valve, a two-way electric water valve, or a springless pneumatic actuator with a 0-10V input. The intelligent actuator integrates a valve positioner with HART or Modbus communication protocol.

[0009] Furthermore, the main control microprocessor has at least one composite control algorithm selected from PID control algorithm, fuzzy control algorithm and feedforward control algorithm. The main control microprocessor controls the supply air temperature fluctuation range of the HVAC system to within ±0.3℃ through closed-loop feedback and adaptive PID tuning.

[0010] Furthermore, it also includes a communication network module, which is connected to the main control microprocessor; The communication network module supports BACnet MS / TP, BACnet / IP, Modbus TCP or LonWorks communication protocols, and is used to upload field-level data to the central monitoring workstation to build a three-level distributed control system of field-regional-central level.

[0011] Furthermore, the outer shell of the DDC control box is treated with phosphating and coated with milky white paint. Heat dissipation holes are provided on both sides of the box. The protection level of the DDC control box is IP20, and the operating temperature range is -45℃ to 65℃.

[0012] Furthermore, the main control microprocessor is also equipped with an energy management module, which is used to execute operation control, energy consumption recording and enthalpy control strategies; The enthalpy control strategy compares the enthalpy values ​​of indoor and outdoor air and dynamically adjusts the opening ratio of the fresh air valve and return air valve of the fresh air handling unit to maintain a constant total air volume and achieve energy-saving control.

[0013] Furthermore, the main control microprocessor is also equipped with safety interlock and antifreeze protection logic; When the antifreeze protection trigger condition is detected, the main control microprocessor executes dual threshold control logic, including issuing an alarm when the temperature is lower than the first threshold, forcibly closing the fresh air valve and starting the electric heater when the temperature is lower than the second threshold, and simultaneously stopping the air supply fan.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: by integrating the main control microprocessor, A / D and D / A modules on the pre-connected PCB and adopting a flip-type wiring structure, the deployment of connecting external lines on site without moving internal lines is realized; when the main control terminal runs the IEC 61131-3 standard programmable runtime, it integrates incremental PID, feedforward and fuzzy self-tuning algorithms to control the air supply temperature fluctuation within ±0.3℃, and supports online download and remote debugging; The communication side is compatible with BACnet / MS-TP, BACnet / IP, Modbus TCP and LonWorks, and constructs a three-level distributed system of field-region-central. It maintains local closed-loop control even when the central network is interrupted. With the enthalpy energy-saving strategy and dual threshold anti-freeze interlock, it takes into account control accuracy, energy saving rate and system security, and solves the problems of messy wiring, rigid algorithms, closed protocols and loss of control when a single machine fails in traditional DDC boxes. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to specific embodiments.

[0016] In this embodiment, please refer to a specific implementation of a DDC control box main control system, characterized in that it includes: a DDC control box, a main control microprocessor, a sensor network, an A / D conversion module, a D / A conversion module, and an actuator system; The main control microprocessor is located inside the DDC control box. The sensor network is connected to the A / D conversion module. The A / D conversion module is connected to the main control microprocessor. The main control microprocessor is connected to the D / A conversion module. The D / A conversion module is connected to the actuator system. The sensor network is used to collect analog signals of the building environment and equipment status. The A / D conversion module is used to convert the analog signals into digital signals and transmit them to the main control microprocessor. The main control microprocessor is used to perform calculations on the digital signals according to preset control logic and generate control instructions. The D / A conversion module is used to convert the control instructions into drive signals to control the actuator system.

[0017] Sensor networks primarily function to calculate and generate analog quantities, as follows: → A / D conversion of digital quantities: temperature, humidity, pressure, CO2… → Main microprocessor operation → Control commands (digital values) → D / A conversion (0–10 V / 4–20 mA) → Actuators (water valves, air valves, frequency converters) The PID control algorithm is as follows: in: Setting value Feedback value Controller output (corresponding to 0–10 V of D / A converter) These are: proportional, integral, and differential coefficients. The discrete-position PID (sampling period T) in DDC has the following formula: The formula for incremental PID is as follows: When the system exhibits large deviations or nonlinearity, fuzzy rules are used to adjust the PID parameters: Input: E = Temperature error level (NB, NS, ZO, PS, PB) Input: EC = Rate of change of error Output: ΔKp, ΔKi, ΔKd get: ; After conversion using the formulas in A / D and D / A: For example, a PT100 transmitter outputting 0–10 V corresponds to 0–50 °C. The formula can be obtained as follows: Output via D / A converter: accomplish The logical criteria and action feedback form a closed loop.

[0018] The DDC control box integrates a wiring module and a PCB circuit board inside its enclosure. The main control microprocessor, the A / D conversion module, and the D / A conversion module are all integrated on the PCB circuit board. The wiring module adopts a flip-type wiring structure. The power supply terminals of the sensor network and the external devices of the actuator system are all connected through the wiring module, and the power lines and network lines inside the DDC control box are pre-connected.

[0019] The internal structure of this enclosure uses wiring modules and PCB circuit boards for installation. The PCB integrates the main control microprocessor, A / D, and D / A wiring modules, which are flip-type. Externally, it connects to sensor networks, actuator systems, and equipment power supplies, replacing traditional screw-based deep cavity wiring with flip-type terminal blocks.

[0020] Its operation steps are as follows: after the main control MPU performs calculations → D / A converter on PCB → internal pre-wiring → flip the terminal block → field actuator.

[0021] The main control microprocessor uses an ARM Cortex-M series microprocessor or an Intel Atom-level low-power SoC chip. The main control microprocessor runs programmable control software based on the IEC 61131-3 standard, which supports online download, version management and remote debugging.

[0022] The sensor network includes at least one of the following: temperature sensor, humidity sensor, pressure sensor, CO2 concentration sensor, differential pressure sensor, flow sensor, and air quality sensor. The temperature sensor is a platinum resistance thermometer (PT100) or an NTC thermistor, the humidity sensor is a capacitive polymer thin film sensor, and the CO2 concentration sensor is an NDIR non-dispersive infrared sensor.

[0023] The actuator system includes switch-type actuators, regulating actuators, and intelligent actuators; The regulating actuator includes a three-way electric water valve, a two-way electric water valve, or a springless pneumatic actuator with a 0-10V input. The intelligent actuator integrates a valve positioner with HART or Modbus communication protocol.

[0024] The main control microprocessor has at least one composite control algorithm among PID control algorithm, fuzzy control algorithm and feedforward control algorithm. The main control microprocessor controls the supply air temperature fluctuation range of the HVAC system to within ±0.3℃ through closed-loop feedback and adaptive PID tuning.

[0025] Supply air temperature control: Calculate e(k) from the measured value y(k) and the set value r(k) of PT100. PID output u(k) → D / A converter converts to 0–10 V → adjusts the opening of the two-way electric water valve Target: Supply air temperature fluctuation ≤ ±0.3 ℃.

[0026] Total control quantity: It also includes a communication network module, which is connected to the main control microprocessor; the communication network module supports BACnet MS / TP, BACnet / IP, Modbus TCP or LonWorks communication protocols, and is used to upload field-level data to the central monitoring workstation to build a three-level distributed control system of field-regional-central level.

[0027] This system constructs a three-level distributed control architecture: field level, regional level, and central level. Field level: Each DDC control box acts as a BACnetMS / TP node or Modbus slave, connected to the RS485 bus via a flip-type wiring module. The DDC box independently operates its local control logic (PID / feedforward / enthalpy), unaffected by the status of the upstream network. After each control cycle, the DDC box packages data such as temperature, humidity, valve position, and energy consumption into BACnetMS / TP frames or Modbus messages, sending them to the regional level via the bus. Regional level: The regional controller, which can be a high-performance DDC or an embedded gateway, polls subordinate DDC boxes (0-64 nodes) via the MS / TP bus, aggregates operating data from each box, executes regional coordination logic, performs whole-floor fresh air balancing and zone temperature optimization, and uploads the aggregated data to the central level via BACnet / IP. Central level: Central monitoring workstation / BMS server, connected to the regional level via BACnet / IP or ModbusTCP, to display the DDC box's operating data (refresh rate ≤2s), trend recording and historical query, alarm management and event push, remote modification of setpoints, remote online download of control programs, and remote forced and debug operations.

[0028] The outer shell of the DDC control box is treated with phosphating and painted with milky white paint. Heat dissipation holes are provided on both sides of the box. The protection level of the DDC control box is IP20, and the operating temperature range is -45℃ to 65℃.

[0029] The main control microprocessor is also equipped with an energy management module, which is used to execute operation control, energy consumption recording and enthalpy control strategies; The enthalpy control strategy compares the enthalpy values ​​of indoor and outdoor air and dynamically adjusts the opening ratio of the fresh air valve and return air valve of the fresh air handling unit to maintain a constant total air volume and achieve energy-saving control.

[0030] The specific formula for the enthalpy of air (dry air + water vapor) is as follows: t: Dry bulb temperature of air (°C) w: Moisture content (kg water / kg dry air), calculated from a temperature and humidity sensor. The main control microprocessor is also equipped with safety interlock and antifreeze protection logic; when the antifreeze protection trigger condition is detected, the main control microprocessor executes dual threshold control logic, including issuing an alarm when the temperature is lower than the first threshold, forcibly closing the fresh air valve and starting the electric heater when the temperature is lower than the second threshold, and simultaneously stopping the air supply fan.

[0031] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A DDC control box main control system, characterized in that, include: DDC control box, main control microprocessor, sensor network, A / D conversion module, D / A conversion module and actuator system; The main control microprocessor is located inside the DDC control box. The sensor network is connected to the A / D conversion module. The A / D conversion module is connected to the main control microprocessor. The main control microprocessor is connected to the D / A conversion module. The D / A conversion module is connected to the actuator system. The sensor network is used to collect analog signals of the building environment and equipment status. The A / D conversion module is used to convert the analog signals into digital signals and transmit them to the main control microprocessor. The main control microprocessor is used to perform calculations on the digital signals according to preset control logic and generate control instructions. The D / A conversion module is used to convert the control instructions into drive signals to control the actuator system.

2. The DDC control box main control system according to claim 1, characterized in that, The DDC control box integrates a wiring module and a PCB circuit board inside its enclosure. The main control microprocessor, the A / D conversion module, and the D / A conversion module are all integrated on the PCB circuit board. The wiring module adopts a flip-type wiring structure. The power supply terminals of the sensor network and the external devices of the actuator system are all connected through the wiring module, and the power lines and network lines inside the DDC control box are pre-connected.

3. The main control system of a DDC control box according to claim 1, characterized in that, The main control microprocessor uses an ARM Cortex-M series microprocessor or an Intel Atom-level low-power SoC chip. The main control microprocessor runs programmable control software based on the IEC 61131-3 standard, which supports online download, version management and remote debugging.

4. The main control system of a DDC control box according to claim 1, characterized in that, The sensor network includes at least one of the following: temperature sensor, humidity sensor, pressure sensor, CO2 concentration sensor, differential pressure sensor, flow sensor, and air quality sensor. The temperature sensor is a platinum resistance thermometer (PT100) or an NTC thermistor, the humidity sensor is a capacitive polymer thin film sensor, and the CO2 concentration sensor is an NDIR non-dispersive infrared sensor.

5. The main control system of a DDC control box according to claim 1, characterized in that, The actuator system includes switch-type actuators, regulating actuators, and intelligent actuators; The regulating actuator includes a 0-10V input three-way electric water valve, a two-way electric water valve, or a springless pneumatic actuator. The intelligent actuator integrates a valve positioner with HART or Modbus communication protocol.

6. The main control system of a DDC control box according to claim 1, characterized in that, The main control microprocessor has at least one composite control algorithm among PID control algorithm, fuzzy control algorithm and feedforward control algorithm. The main control microprocessor controls the supply air temperature fluctuation range of the HVAC system to within ±0.3℃ through closed-loop feedback and adaptive PID tuning.

7. The DDC control box main control system according to claim 1, characterized in that, It also includes a communication network module, which is connected to the main control microprocessor; The communication network module supports BACnet MS / TP, BACnet / IP, Modbus TCP or LonWorks communication protocols, and is used to upload field-level data to the central monitoring workstation to build a three-level distributed control system of field-regional-central level.

8. The main control system of a DDC control box according to claim 1, characterized in that, The outer shell of the DDC control box is treated with phosphating and painted with milky white paint. Heat dissipation holes are provided on both sides of the box. The protection level of the DDC control box is IP20, and the operating temperature range is -45℃ to 65℃.

9. The main control system of a DDC control box according to claim 1, characterized in that, The main control microprocessor is also equipped with an energy management module, which is used to execute operation control, energy consumption recording and enthalpy control strategies; The enthalpy control strategy compares the enthalpy values ​​of indoor and outdoor air and dynamically adjusts the opening ratio of the fresh air valve and return air valve of the fresh air handling unit to maintain a constant total air volume and achieve energy-saving control.

10. The main control system of a DDC control box according to claim 1, characterized in that, The main control microprocessor is also equipped with safety interlock and anti-freeze protection logic; When the antifreeze protection trigger condition is detected, the main control microprocessor executes dual threshold control logic, including issuing an alarm when the temperature is lower than the first threshold, forcibly closing the fresh air valve and starting the electric heater when the temperature is lower than the second threshold, and simultaneously stopping the air supply fan.

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