Study On The Modulation Topological Structure And Modulation Algorithm Of The Current Source Inverter

Current Source Inverter(CSI)has the advantages such as controlling the current more directly and conveniently,faster dynamic response,easy regeneration capability,and implicit short-circuit protection,has been widespread concern in the power electronics industry.We study the topology of the current source multilevel inverter and the corresponding modulation algorithm from two aspects of single phase and three phase in this dissertation and proposed a new corresponding modulation that suitable to the CSI.Meanwhile,Introduce this algorithm into the direct power control of current source rectifier.1.This dissertation introduce the topology of the current source inverter from single phase and three phases,and analyze the working principles of various topologies in detail.Meanwhile,the switching table of each topology is given,and giving the simulation results.2.Introduce the working principle of the modulation algorithm such as PWM,PWM and PWM in detail,and according to the characteristics of current source inverter,introduce the fanction that transform two logic switch function into three logic switch function.Giving the modulation algorithm which adapts with various topologies,and conduct the FFT analysis of their output waveform for these algorithms,compare their advantages and disadvantages.This dissertation also compare and analyze the advantages and disadvantages of each algorithm,which lays the foundation for the following research.3.Introduces the principle of DPWM algorithm,and then proposes an improved DPWM algorithm,this algorithm can further improve the fundamental content and reduce the harmonics of the output current when been compared with the traditional algorithm.At the same time,when compared with the conventional algorithm,the proposed algorithm also greatly reduces the switching time.Compared with the traditional DPWM algorithm,it is more suitable for current mode inverter.Finally,the correctness and effectiveness of the proposed algorithm are verified by a large number of simulation experiments.4.Introduces the principle of direct current control and direct power control of current source rectifier,and compaire them by the simulation.Then,the improved DPWM algorithm is introduced into direct power control,under the premise of don't affecting the power tracking effect,it not only further improved the output waveform performance,and reduce the switching frequency,thereby prolonging the service life of the power switch tube.5.Built a prototype of three-phase current source PWM inverter.The design of the DSP control system is analyzed in detail,and giving the programming flow to realize the improve DPWM algorithm using DSP.Finally,the experiment of the conventional multi carrier stackalgorithm and the improved DPWM algorithm are doing on the prototype to verify the correctness of the theoretical analysis.