Research Of Static Var Generator Based On IGBT

With the rapid development of power electronics technology, more and more electrical equipment posed by the power electronic components used in power system.But some series of power quality problems came with it.Various electrical equipmentes especially some of the sensitive electrical equipments need relatively high power quality. As one important aspect of power quality improvement, The reactive power compensation technology has got more and more important.Especial for the voltage sages and unbalances, which are so caused by ground faults or unbalanced load in the power system, often interrupt the operation of sensitive elerctrical equipments. As a effective dynamic reactive power compensation device for power system, the research on STATCOM/SVG is becoming a hot field of power electronics. Compared with the traditional reactive power compensation devices, STATCOM has many advantages, such as fast response, small volume, wider adjustable range and higher wave-quality of compensation current.The STATCOM has becoming an important trend of dynamic reactive power compensation.Firstly, this thesis analyzed the dynamic reactive compensation mechanism of the IGBT-based STATCOM. Then, the STATCOM steady-state mathematical model was established and the mathematical modle based on the sequencen algorithm was derived. Based on this, the thesis proposed a hybrid control method with the combination of positive-sequence and nagetive-sequence voltage component.To achieve the control objectives, it needs to accurately detect the compensation signal in advance.The positive and negative sequence componets were converted to direct signals used d-q coordinate transformation.In the theoretical analysis, the thesis gave a detailed introduction on the hardware and the software design. Hard d-q ware circuit design includes a main circuit,driving circuit,signal detection circuit and the DSP processing circuit.Then gave the detailed calculation of parameters of devices.On the software,the paper adopted the module design, including the initialization module, frequency measurement module, data processing module and SPWM pulse generator module.Finally, the simulation on the designed STATCOM was performed using MATLAB/SIMULINK. Some of circuits were test based on the established experimental platform. Both the simulation and the experimental results shows that the designed STATCOM can suppress the unbalanced voltage caused by the unbalanced load. The results also indicate that the theory and technology proposed in the thesis are feasible and effective.