Multi-Switch Based Current-Source Reactive Power Compensation

With the increasing complex of grid system and more kinds of electrical equipments, the problems which are caused by reactive power are getting more and more serious. Recently, the TSC and STATCOM are still the most widely used reactive power compensation devices. In the applications, both of these two devices are inadequate in a certain areas. Consider the existing problems, this paper proposed a new type of Multi-Switch based current-source Reactive Power Compensation device, mainly worked in the four areas as listed below.First, consider the cost and performance of the reactive power compensation, a new structure of the Multi-Switch Based Current-Source Reactive Power Compensation was proposed. The structure Used SCRs as the main power switches and IBGTs as assistant switches, greatly reduced the cost; with the similar working method as the STATCOM, it solved the problem such as the capacity and the stepless regulating. It provided a new Solution of low-cost and high-efficient reactive power compensation device. This paper sketched the specific topology, proposed two improving circuits based on the study of the switching characteristics of SCR, then modeled and analyzed the main circuit.Second, the analysis of the reactive power compensation device control strategy. Briefly introduced the instant reactive power theory and the detection method; provided the direct and indirect control methods. This paper used the indirect control method to control the reactive compensation devices, studied the mathematical model and the static and dynamic stability of the indirect control method in detail. Then discussed the specific process of the command currents generating, proved it with simulation and experiment, laid the foundation for the control of the actual device. Third, according to the synchronization problem of active power filter, three phases phase-locked loop is introduced in this paper. The practicability and validity of the three phases PLL is proved by both simulation and experiments.At last, this paper studied the control signal generation methods of the current-source AC/DC converter, mainly focused on the SVPWM method. SVPWM area dividing and vector operating time calculating are discussed in detail. And based on the logical characteristics of the multi-switch topology, A new practical method was also provided to use TMS320LF2407 DSP to carry out the specific switching logic. The final system experiment showed a good dynamic and static performance of the new type of the Multi-Switch based current-source Reactive Power Compensation device.