Research On The Space Vector Pulse Width Modulation And Its Realization Of Three-Phase UPS Digital Control System

This paper based on the project" The Research and Development of High-power On-lineUPS Control System". With the development of science and technology, the requirements ofmodern electrical equipment for power quality are getting higher and higher, no matter whenthe mains is functional or not, they require UPS(Uninterruptible Power Supply) can provideclean, stable and reliable power for normal load. With the development of high-performanceDSP controllers, digital control becomes a trend and direction in its further development.Using DSP chip as the main chip makes the product easier to optimize and upgrade.The DSP technology can improve the stability and reliability about output voltage of theUPS products in order to output high-quality voltage waveform and strengthen the dynamicperformance of the system.The key point to realize the main control system of On-line UPS is to realize the digitalcontrol of three-phase inverter.This thesis introduces the whole design of DSP-based digitalclosed-loop control system of three-phase inverter, that is software design of digitalclosed-loop control system of inverters. This thesis researches deeply on the space vectorpulse width modulation (SVPWM) and closed loop control system of three-phase inverter.Thethesis explains the meaning of three-phase unbalanced load. It proposes a kind of SVPWMcontrol strategy.This thesis uses Matlab software to simulate the closed-loop control system ofthree-phase inverter meanwhile verify the correctness and feasibility of the control scheme.Then, according to the control scheme, we design the main control system of UPSprototype. In the design of system software, The thesis makes a detailed derivation ofalgorithms, such as SVPWM control algorithms, digital PI algorithm, ADC linearity errorprocessing algorithms and so on. At the same time, the thesis makes simulation analysis andgives the main program flowchart.Finally, according to software flowchart and hardware structure of the main controlsystem, the main control system of a prototype is designed.After making a series ofexperiments on the prototype, it gives the experimental waveforms.