The 3-terminal converter is built with HV IGBT transistors with 6,5kV blocking voltage. Transistors are controlled by fiber optic from DSP and FPGA based controller. Entire device consists of three subcircuits, which create configurable bidirectional multilevel converter, based on "DIODE CLAMPED" structure. The first converter is composed of three active rectifiers connected in series, supplied by isolation transformer. The second converter is four-level inverter and rectifier, coupled directly with 6kV AC grid. The third part is chopper as active voltage balancing system. All subcircuits are connected to a common 10kV DC link. Implemented algorithms are based on space vector modulation techniques (SVPWM). For operation with highly distorted working conditions there are advanced PLL methods for harmonic identification applied. Application of technologically advances elements and sophisticated algorithms allow to satisfy actual needs and standards.

TECHNICAL PARAMETERS
Voltage source (with transformer): 6-20kV AC
Voltage source (without isolation): 6kV AC
Output voltage: 6kV AC
DC link voltage: 3 x 3,3kV DC
Grid frequency: 1-2kHz
Rated power: 1MVA
Cooling: Forced air flow
Control: DSP Signal Processor, FPGA
Input parameters: Industrial PC with touch screen