Research Of Three-Phase High Power UPS And Control Technology Base On Three-level Inverter Technology

Uninterruptible power supply(UPS)is a very important emergency power supply.In the event of an interruption of the input market,UPS can continue to supply power to the office computer for a period of time,while in the event of abnormal electricity,UPS can also effectively purify the municipal electricity.Currently,UPS is widely used in enterprises and even in the family,and its importance will be improved.Firstly,this paper introduces the background of the subject and its technical status.The composition and main performance indexes of the power supply system of UPS are analyzed,and the working principle of the circuit in five working modes is analyzed.Studied the working principle of the main modules of the UPS,including three-phase bridge type all control rectifier circuit and BOOST the booster circuit,battery charging module,inverter modules working principle and control strategy.On this basis,the rectifying circuit of UPS system,BOOST PFC circuit,sampling circuit,current sampling circuit and voltage sampling circuit),the inverter module for the design,the inverter of main power semiconductor switch tube,the output inductor,the dc bus capacitor and the output filter capacitor parameters,such as a detailed calculation and analysis;In addition,the thesis to the heart of the UPS inverter to the study on control system,establish the control model of three level inverter circuit module,analyzed the symmetric digital PWM wave generation mechanism,realize the SPWM wave output signal based on DSP.The paper has completed the overall design of the system control software,including the system main program,the timing interrupt program,the inverter voltage control loop and the program design of the current control loop.Finally,I have tested the main performance indicators of designed UPS prototype,including the dynamic characteristic of the output voltage waveform,the output current,output voltage harmonic distortion rate of accuracy and efficiency of the machine was tested.The experimental results verify the rationality of hardware and software design and the correctness of theoretical analysis.