Research On Z-source Inverter Harmonic Suppression Strategy

With the development and progress of society, power electronic technology is becoming more and more mature, and inverter has been very widely used. A large number application of inverter and the related equipment will increase the national power grid harmonic pollution,and the problem has got the attention of many scholars.General application of the inverter can be divided into two types of voltage and current. The two types of inverter is either a step-down or a boost model, thus caused its application scope is narrow. The cause of this situation is that the two types inverter bridge arm cannot conduct at the same time. Because of the limitations on their own these two types of inverter in many applications lead to low efficiency and the cost is too high. If you want to increase both the application range of the inverter, it must transform the original level of circuit structure into a secondary circuit structure. Doing that will cause a great waste of resources. The proposed of Z source inverter can well solve the shortcomings of two types of inverter, and don’t have to increase the conversion circuit control series when it realize the lifting pressure ability. Therefore, the good circuit structure will has great application scope in the future life and production.Under the limitation of structure and control method of the inverter, the output side of the Z source inverter will contain a large number of unwanted harmonic interference. Therefore, in order to increase the range of application of Z source inverter, we must solve this problem. We can solve this problem mainly from two aspects, on the one hand is to use the modified circuit, on the other hand is to optimize the control method. Finally, the output reasonable filter design is also very important, it can greatly reduce the distortion of the output voltage and current to achieve the harmonic suppression effect.The main content of this paper is:(1)This paper first analyzes the basic circuit of Z source inverter, through comparing with general inverter its principle of working and boosting. Analysis on different circuit structure can get the direct between step-up factor B and duty ratio Do and this will be conducive to the Z source inverter output efficiency.(2)Through the analysis of the Z source inverter in different control strategies on the influence of the inverter output voltage harmonic will be conducive to select more reasonable control method. Then use MATLAB to verify the control method and get the control efficiency.Analysis the total harmonic distortion under the state of the steady state and get the inhibition effect.(3)Analyzing the stress of the power devices with the model of Z-source inverter. Then select the suitable capacitance and inductance components by the requirements of the Z source network.Researching the influence under the analyzes of different carrier.Adding three times waves in the modulation wave to analyze and verify the Z source output efficiency and the influence of the THD.Finally verify the correctness and effectiveness of the theoretical with reasonable filter design.