Research Of Three-level Static Synchronous Compensator

With the development of the social economy, the requirement of users for the power quality is higher and higher and the reactive power compensation problem is particularly prominent. Compared with other reactive power compensation devices, the static synchronous compensator has been widely used because of the better compensation effect, the faster regulating and the longer operating life. At the same time, combining the multilevel inverter with the static synchronous compensator, its performance is further improved. This paper mainly studies the three-level static synchronous compensator.In this article, firstly, the significance and the development history of reactive power compensation were introduced by comparing the advantages and disadvantages of different reactive power compensation devices, then, the steady-state performance and stability of STATCOM was analyzed by introducing the pricinple and setting up the mathematical model of STATCOM. In this paper, STATCOM can be divided into four parts, the first part analyzes the working principle of main circuit in detail; the second part introduces the various reactive current detection and especially p-q and ip-iq detections which based on the instantaneous reactive power theory; the third part introduces the direct current control method and the indirect current control method which has been widely applied. Combining with the adwantages and disadwantages of two methods, designs a current decoupling control based on voltage space vector pulse width modulation(SVPWM); the fourth part makes a theoretical derivation for SVPWM.The STATCOM overall system simulation model is built with the MATLAB simulation tool based on theoretical study of STATCOM. By comparing the simulation results of the p-q and ip-iq reactive current detection when the power grid voltage distort and not, we knows that ip-iq method has a wider application range than p-q method, so we choose ip-iq method as the reactive current detection. The simulation results of each submodule of SVPWM verify the correctness and rationality of the SVPWM model. Through analyzing the simulation results of a variety of operation for STATCOM, show that the three-level STATCOM has a good compensation performance and dynamic performance in this paper.Finally, according to the simulation analysis, the hardware circuit and software control program are designed. At the same time, we get the experiment waveform.