Design and implementation of static synchronous series compensator with a soft-switching H-bridge inverter with DSP-based synchronization control

The implementation of an H-bridge inverter which is aimed to be a building block for Flexible AC Transmission Systems, namely Static Synchronous Series Compensator, is explained in detail The inverter is implemented with the ready-made module from Mitsubishi PS21997 A quasi-resonant topology that is comprised of a clamping circuit and a resonant circuit, is also implemented in order to achieve soft switching and thus increase the overall efficiency of the inverter by decreasing switching losses that reach considerable values with the abundant number of switches and a switching frequency of the order of kHz The control loop is realized by means of a Digital Signal Processor in order to achieve synchronization with the power line and power flow control The overall system is characterized by a 6-pulse inverter the input voltage of which is not a pure DC but a waveform that occasionally reaches zero level with the help of a quasi-resonant circuit at the source side, and which can keep detect the power line current and infect a voltage which is in full quadrature (90 degree phase difference) with it This system is aimed to be a building block for FACTS devices such as Static Synchronous Series Compensator (SSSC) The motivation of designing a more efficient and dynamic inverter with high power quality is to construct more efficient and effective FACTS device