Development Of Embedded Energy-saving Controller For Central Air Conditioning

With the economic development and the increasing energy consumption, the power consumption of the central air conditioning has accounted for 20% of the total electricity consumption. The special controllers on the market are difficult to control the overall system due to insufficient features. Therefore, a new energy saving controller has huge market potential and economic benefits.Firstly, according to the requirements of central air conditioning, the iCoupler technic of ADI is adopted to make electrical isolation of 2.5KV, which can achieve an effect of high data rates, good timing accuracy and strong transient common-mode rejection; dual CAN bus is used in the communication between the controllers; 100M Ethernet is introduced between the controllers and position machine; various types of IO interface are adopted to meet the complexity of control points,; other kinds of communication are included to facilitate the maintenance, expansion and upgrade. Secondly, ARM Cortex-M3 based Microcontroller LM3S8970 is used as controller core. Four-layer PCB control board is designed. The embedded controller has 8 AI, 8 AO, 10DI, 10DO, and dual CAN, Ethernet, RS-232C, IrDA SIR, SSI communication are integrated.Thirdly, the architecture and its detail scheme of the software system for energy saving control system of central air conditioning have been proposed. A scheduling strategy of control first and tail-chaining supported is utilized, which has achieved the real time of the control software; Compliance with programming norms, the software has been developed, including board-level definitions, drivers, communication and control algorithms.Finally, an embedded testing platform has been established, whose framework is hardware facilities+EKI-LM3S2965 and IAR EWARM. The hardware testing, software testing and hardware/software system testing of the controller are carried out.Testing results have proven that the hardware and the software system of the controller is stable, reliable, and the controller can trace the given signal in real time, which indicates that the controller can be used in energy saving control system of central air conditioning. Then, the embedded energy saving controller has a great and profound significance at improving performance and energy conservation. Moreover, the embedded testing platform established is of a certain universal, suitable for testing of related embedded products.