Research On The Compound Control Method Of The10kVA Three Phase VVVF Power Supply

With the development of electric and electronical coverting technique,thetechnology of SPWM and SVPWM become more sophisticated.Variable voltagevariable frequency(VVVF) power more and more is widely used in various fields. Inorder to obtain high steady-state accuracy and good dynamic performance, the qualityof the output waveform of the VVVF power is proposed more high requirements.VVVF power control strategy has been the hot spot of the power electronics industry.Firstly, this paper introduces the research status of the VVVF power at home andabroad. Secondly its mathematical process is given a detailed analysis, as well as thecourse of the implementation of control technologies is briefly discussed. By analyzingthe characteristics of the various control strategies, an overview of its main advantagesand disadvantages is introduced. Finally, the common problems and differences of thecontrol of the three-phase VVVF is obtained.The mathematical model is an important theoretical basis for analysis of the VVVFpower.The mathematical model expressions of three-phase VVVF power is detailedderived in dq two-phase rotating coordinate system, abc three-phase static coordinatesystem and αβ two-phase stationary coordinate system. The working principle and theparameter constraints of the three-phase VVVF power are describes by the theoreticalanalysis.Due to the disturbance suppression of double closed-loop control is ineffective, anddo not have the functionality of the online tuning parameters. Adding fuzzy control, acompound control method is designed. Fuzzy PI double closed-loop control method foreliminating periodic interference effect is not good. Taking the good elimination ofperiodic interference of repetitive control into account, we can combine fuzzy PI controland repetitive control to meet control system.By a large number of simulation experiments，the paper can draw two conclusions:firstly, the quality of the output waveform is high;secondly, using fuzzy PI control toovercome parameters of a single dual closed-loop can not be self-regulating in the caseof load and no-load, the system has faster dynamic response performance in the case ofload changes. The simulation draw a conclusion: whether it is connected resistive loador non-linear load, the output voltage waveform THD values of compound control arevery low, it can meet the design requirements of the three-phase VVVF power.The paper also research the problem of the phase-locked, an improved softwarephase-locked loop based on2ω notch is designed. In the case of three-phase voltageimbalance and distortion, the SPLL also can achieve a good result. The summary of thepaper and the outlook of future works are described in the last chapter.