Development of self-commutated SVC for power system

Control Strategies of a Hybrid Multilevel Converter for Expanding Adjustable Output Voltage Range

“…Thus, the 6m±1 (m: integer) harmonics in the output voltage produced by the GTO inverters are eliminated. 2 In this paper GTOs represent high power devices. High power devices such as IGCTs and IEGTs can be also employed instead of GTOs.…”

“…2(b) and (c), respectively. The combined voltage of the two GTO inverters is VGTO = VGTO1 + VGTO2 (2) and is shown in Fig. 2(d).…”

Development of a control system for a high-performance self-commutated AC/DC converter

“…In Japan, two sets of 50 MVA static var compensators using gate turn-off thyristor (GTO) converters with a nominal dc voltage of 16 kV and another of 80 MVA with dc 4 kV, which are referred to as "static synchronous compensators (STATCOMs)" in the FACTS projects, have already been installed and are in operation [3] [4]. Since these converters are of the voltage-source type, a scheme for high-speed control of dc voltage and reactive power was developed, and satisfactory operating experience in actual grid systems has been obtained.…”

Investigation of hybrid multilevel DC/AC inverters

“…Early, a large snubber is used to limit the dv/dt of the switching component during the turn-off period [103], and a variable inductor is to be placed between each gate drive circuit and the corresponding switching component in order to control the rising/falling time and to adjust the transient voltage [44,104]. These modifications will increase the losses and reduce the dynamic performance, so a system with fewer GTOs connected in series provides better voltage sharing, and improves efficiency and dynamic performance [51].…”