Research On Digital Control Of UPS Based On DSP

Digital control,in which software replaces analog and digital instruments,can increase the integration of the product;promote the flexibility and intelligence of the system. Therefore,the digital control tends to be one of the promising methods in the UPS control technology.This article introduces a kind of digital control technology based on DSP,named single-phase double conversion UPS,and put forward a digital control project the software and hardware. The main hardware of the system includes isolating and driving of the PWM signal,sampling and processing of the signals of control,as well as hardware protection circuit. The system software can realize each functional module in the UPS. Firstly,design the software phase-closed loops;secondly,realize the double closed loops control of the instantaneous value and the virtual value. Furthermore,the dynamic flux imbalance of the output transformer caused by ordinary PI arithmetic is analyzed in detail. A new solution for flux balance by sampling the instantaneous primary current of the output transformer and introducing the on-line calculated bias current component into the voltage regulation arithmetic is presented.The dissertation,in addition,discusses the malfunction monitoring and protecting,such as overload. The discussions on the speed control of fan according to the output power,and some monitoring functions,such as the isolation sample of battery's voltage and its management,which will improve the reliability and intelligence of the system,are also included in the dissertation.A great lot of analysis,simulations and experiments have verified the system's feasibility and advantage. The research in the dissertation,to some extent,has paved a way for the further research,improvement and application in the digital control of UPS.