Analysis of the Discontinuous Pwm Controlled D-statcom for Reactive Power Compensation Applications

Original scientific paper The scope of this paper covers the investigations of discontinuous PWM (DPWM) control of the Distribution Static Synchronous Compensator (D-STATCOM). Various DPWM methods have been widely used in motor drives for controlling the inverter and reducing power losses. With the rising demand for energy, energy efficiency has currently become an issue of vital importance. As a result, the use of the D-STATCOM in distribution systems is becoming increasingly common. In this study, DPWM methods were used for the D-STATCOM inner control. For the outer control, phase angle control was used and PWM methods were adapted to this control algorithm. In addition, conventional continuous PWM (CPWM) methods were applied to the D-STATCOM for comparison purposes. All simulations were performed in the MATLAB-Simulink software environment. Power losses have a significant impact on the D-STATCOM; therefore, a simulation model was developed to calculate the conduction and switching losses in order to investigate the effectiveness of DPWM methods in reducing the D-STATCOM power losses. Results showed that the utilization of different DPWM methods in the D-STATCOM was suitable for high modulation indexes. This clearly illustrates that, according to different DPWM methods, a reduction of from 14 % up to 50 % in D-STATCOM switching losses can be achieved. Furthermore, this study proposes the use of CPWM and DPWM methods in low and high modulation indexes, respectively, according to the requirements of the distribution system.