Study Of Space-Vector PWM Algorithm Used In D-STATCOM

Var compensation is one of dominating methods for keeping power system in condition of favorable running. Now, var compensation devices in wide use are synchronous var compensation equipments combining with power electronic technique. Because of its many advantages, Static Synchronous Compensator has been the main direction of developing synchronous var compensation technique.After the main circuit of STATCOM is decided, this paper utilizes digital signal processor as controlling apparatus according to its working principle and the demands for pulse generator's function. Through analyzing the controlling principle of conventional space-vector PWM and its disadvantages when used in three-level and multi-level inverter, this dissertation presents an improved SVPWM which can use two-level SVPWM and simplify total algorithm by convertering three-level space vector diagram into two-level space vector diagram as well as transforming reference voltage. Meanwhile, a corresponding strategy is also introduced to solve the inherent neutral point potential fluctuations of diode-clamped circuit. Moreover, this paper proves the utilization of new SVPWM in multi-levelinverter above three with an example of five-level inverter. The MATLAB has been made use of to simulate and the results shows that mentioned method can effectively realize controlling transistors and resolve neutral point unbalance.Finally, the way selecting main elements and designing scheme of pulse generator based on DSP (TMS320F2407) is shown in this dissertation, and the communication between the controller and the pulse generator is achieved with SPI, so the control strategy of total digitization is realized really.