The FEC1900 cabinet comprises all devices needed to build up a modular converter system.
Pulse rectifier and inverter based on IGBT modules on water-cooled, easy-to-change power stacks.
DC-link made of film-capacitors.
Break chopper and break resistor.
Controller boards linked via fast bus system (EtherCAT).
Generator contactor, main contactor and precharge-circuit.
Generator-side filter (du/dt) and grid-side filter.
Heat exchanger air-to-water for cooling of all passive parts: cabinet has IP54.
The modular concept is suitable for electrical as well as permanent magnet excited synchronous generators and offers many benefits, compared to single converter solutions. For example, in case of a device failure, power generation can go on with only a small reduction in peak power because the defective module can be completely electrically separated. Under partial load, some of the modules can be switched off in order to reduce losses and to extend their lifetime. The dimensions of a single cabinet are rather small, so the converter can be installed after the erection of the tower.
The main advantages can be summarised as follows.
Combines high power density with reasonable costs.
Protection class and cooling type allow offshore use.
All serviceable parts are easy to replace.
Reduced grid current harmonics.
New control algorithm allows managing symmetric and asymmetric voltage drops.