Research On Static Synchronous Compensator (STATCOM) Based On Multiple Models PI Controller

Static Synchronous Compensator (STATCOM) can effectively compensate the reactive power and maintain the voltage of the point of common coupling in order to achieve the purpose of improving the power energy quality. Compared with the traditional Static Var Compensator (SVC), STATCOM has better properties of reactive power and voltage stability, so in recent years STATCOM has become a hot research.For the purpose of maintaining the voltage of the point of common coupling of STATCOM, based on direct voltage PI control scheme,for the shortage of the scheme unable to effectively adapt to the change of load, a control scheme which is based on multiple models PI control of direct output voltage control of STATCOM is proposed in this thesis. According to the amplitude of the voltage, multiple models are built. Then the control scheme, which combines the multiple models scheme with PI control, is applied to adapt to the impact of different voltage reducing of the point of common coupling under different impact loads, So the speed and accuracy of voltage control of the point of common coupling will be satisfied.However, in some other situation, system voltage will not change significantly, the change of load mainly embodies in the change of power factor. So in this thesis, the models are built based on the change of load power factor, and direct output current control of STATCOM based on multiple models PI control is proposed. Compared to traditional PI control scheme, this new control scheme can effectively adapt to the change of power factor by the change of load, and after compensating, the power factor of the system can be maintained to 1 or so.In the end, three-phase three wire STATCOM is researched by experiment. Firstly, in the point of the realization of hardware, the topological structure and component parts of STATCOM are introduced. What's more, in the point of the realization of software, the main control scheme and program flow are proposed. Finally, the system is tested, the experiment of instruction reactive current output and the connection of 380V grid are made. The experimental results show that the STATCOM has high precision of reactive current output and a good effect.