Full-bridge Reactive Power Compensator with Minimized Equipped Capacitor and its Application to Static Var Compensator
This project discusses reactive power compensators from the point of stored energy in the capacitor, and proposes a single-phase full-bridge configuration of semi-conductor switches to be used with reduced equipped capacitance for reactive power compensation. By applying this concept to shunt type static var compensator, a static synchronous compensator (STATCOM) can be achieved with reduced sized capacitor. Additionally, the switching loss can be reduced due to its distinctive capacitor voltage waveform which swings at the double of the line frequency. Modulation technique and capacitor voltage control method based on the reduced capacitance and high voltage ripple in the capacitor are proposed.
Usually series compensator is required to inject only small percentage of voltage compared to the system voltage, since the purpose of using series compensation is canceling existing unwanted series inductance. Therefore, line frequency switching can be an option since generated harmonic components in total voltage and impact to the current can be within an acceptable amount. A gate commutated series capacitor (GCSC) is another type of series compensator, which is a series connected ac capacitor with a semi-conductor shunt switch and is operated with line frequency switching.
This project discusses common understanding between the ‘voltage source converter based’ and the ‘capacitor based’ reactive power compensators, and proposes a modulation controlled full-bridge reactive power compensator with reduced and optimized capacitance. The proposed compensator has advantages from both types, low harmonics characteristics by the modulation which comes from the voltage source converter based compensator and small required capacitance which comes from the capacitor based compensator.
TOOLS AND SOFTWARE USED:
- MP LAB
Takanori Isobe, Member, IEEE, Daisuke Shiojima, Kyohei Kato, Yoel Rosales, and Ryuichi Shimada, Member, IEEE, “Full-bridge Reactive Power Compensator
with Minimized Equipped Capacitor and its Application to Static Var Compensator”, IEEE Transactions on Power Electronics, 2015