Research And Design Of Three Phase PWM Converter

Practically in order to let the electric equipment work in ideal state, it usuallyneeds to convert power by energy conversion devices in the development of modernindustry. But most of the energy conversion devices will produce large amounts ofelectric power harmonic in power transmission, transformation and even loadabsorption, which will result distortion of voltage and current waveform in power grid.And it may also add a lot of harmonic into the power grid, reducing the power factorand power quality, damaging electrical equipment, harming the life of electricalequipment, and even threatening the safety of power grid. Therefore, it is veryimportant to study how to suppress the harmonic pollution.At present time, there are two ways to solve the power grid harmonic pollution:adding active power filter (APF) or active power compensator (SVC) to cancel theharmonic in power grid; researching and designing a power electronic conversiondevice which has low harmonic pollution and the unit power. The second way canfundamentally solve the problem of power grid harmonic pollution.Aiming at the problem of power grid harmonic pollution of traditionaluncontrolled rectifier and thyristor rectifier, we adopted the second way to develop athree-phase PWM rectifier with low harmonic pollution. The three-phase PWMrectifier can realize unit power factor and two-way-flow of energy, besides it has fastdynamic response performance.Firstly, I have read a lot of references and understood the development situationof current converters. I analyzed the hardware topology structure and the workingprinciple of three-phase voltage source PWM converter, and established amathematical model based on dq coordinate system in this paper.Secondly, the control strategy of three-phase PWM inverter is discussed here andthe double closed loop PI control method is also studied deeply. By the PSIMsimulation software, the simulation model of the system is set up to optimize andvalidate control strategy of the system.Once again, the system hardware circuit is designed, including the systemtopology and the determination of main circuit parameters. Control circuit is builtwith the DSP2812. At the same time, the software programming is completed based on previously analysis SVPWM control strategy.Finally, after the debugging of the three-phase PWM inverter system, theexperimental result shows that the control strategy is correct.