The Research On Delta UPS Based On Digital Control

At present, the mainstream market existing UPS products are those with double conversion structure, high cost, efficiency is close to the limit, and further reduce costs, the space of improving the efficiency is very small. Replace the full power conversion with part of power conversion is a good idea to improve the system efficiency. Thus, Delta conversion UPS emerges under this guiding ideology.This paper analyzes the advantages and disadvantages of UPS already on the market, and makes a comparison with the Delta UPS. Then it analyzes the direct and indirect control strategy, and chooses direct control strategy by comparison. Introduce the Delta UPS system structure, and make a more comprehensive analysis of the three-phase Delta UPS in various states of power flow. Especially the battery charging power flow state analysis in the condition that the input voltage fluctuates for the study of Delta UPS battery charge control provides the reference. Analysis the reason of the output voltage distort when UPS with nonlinear load and the application of quasi resonant control makes the distortion is low. Delta UPS already on the market charge and discharge the battery frequently when the grid voltage fluctuations, resulting in shorter battery life. To solve this problem, a method that real-time calculates the input current according to the load is proposed.An experimental platform is built. Simulation and experimental results verify the theoretical analysis and the effectiveness of the proposed improvements or solutions.