Research On UPS Inverter Control System And Parallel Systems Communication Based On CAN Bus

In recent years, as electricity equipment requirements for performance and reliability of power supply increasing, uninterruptible power supply (UPS) has been widely applied, and plays a more and more role. This paper studies inverter, the core part of UPS.Single-phase UPS inverter employs diode-clamped three-level inverter circuit as the main circuit. SPWM modulation of three-level inverter uses single sine wave modulation by double triangular carrier modulation method. Paper using state space average method to model three level inverter, get inverter control model. Considering the main factors influencing the inverter output voltage waveform distortion, in order to obtain high quality output voltage steady state waveform and fast dynamic response, puts forward a combined multi-loop control scheme, where double closed-loop control inside, repetitive control in the middle and root-mean-square (RMS) control outside, and design the parameters of the control system.According to the requirement of the UPS inverter system for real time, paper introduces embedded real-time operating system μC IOS-Ⅱ, implements μC IOS-Ⅱ to DSP control chip TMS320F28335 transplantation. On this basis, analyses the control timing of UPS inverter composite control scheme, and gives software realization process of composite control scheme, the generation of SPWM modulation process is introduced, uses the McBSP module implements double DSP communication without master-slave relationship. Then, the validity and reliability of the design are verified through the experiment, the experimental results show that the inverter output voltage waveform of harmonic content is less, dynamic response fast, performance of the system good.Finally, UPS inverter parallel systems communication based on CAN is designed. The features of CAN bus, format of extended data frame and communication mechanism are detailed. The structure of eCAN module of DSP control chip are introduced. The paper also presents the hardware interface circuit of CAN controller and CAN communication network, then presents the software design of communication based on CAN bus. The experiment show the results of parallel systems communication.