Application Of CAN Communication In Paralleled UPS System Based On RTOS

Uninterrupted Power System(UPS) provide reliable and uninterrupted electricity to critical load in case of power failure. It has been widely used in various fields such as banks, medical treatments, and railway transportation. As technology develop, users want UPS to be more reliable and intelligent. Field bus is a new generation of distributed control system, which meets the networking trade of UPS system. It has powerful life and has taken an epochal change to the UPS control system technology.UPS is taken as the object to be studied in this paper. A further study is made based on the theory of real-time communication technologies with the field-bus control system. The details are showed as follows:Firstly an analysis is made on the kernel schedule algorithm in ?C/OS-II, which is an embedded real time operation system. Based on UPS real time communication characteristics, a new kernel schedule algorithm is proposed in this paper. An efficient task communicate method which improve the reliability and real-time ability of UPS is also been referred.Secondly Controller Area Network(CAN) was introduced based on RTOS. As paralleled UPS system needs application layer protocol of CAN, a general communication protocol in UPS application layer was designed in this paper. Including message transmit format, data analysis rule, and application function division, UPS-CAN also formulate the network management rule to control master-slave network and improve reliability of paralleled UPS system.Finally, the new kernel was ported into Cortex-M3 processor which named LM3S9B92 and tested. UPS-CAN protocol was also applied in 20kVA module parallel UPS in order to test the bus data and hot plug function. Experimental results shows that system is real-time, reliable and stable.