Methods of starting power converter systems, and power converter systems

A power converter system comprising:

• a power converter comprising a first converter including a plurality of semiconductor devices, each semiconductor device including at least a controllable semiconductor switch having a threshold voltage and a gate voltage for normal on-state conduction, the first converter having first and second DC terminals connected to a DC link having a DC link voltage, and a plurality of AC terminals;
• a controller-configured to supply current to the first converter and enabling a short circuit state of the first converter by controlling semiconductor switches of the first converter to create at least one short circuit path through the first converter that carries the supplied current;
• and
• wherein at least one of the semiconductor switches in at least one of the short circuit paths is operated with modified on-state conduction to increase conduction losses by applying to the at least one of the semiconductor switches a modified gate voltage that is less than the gate voltage for normal on-state conduction,
• wherein the modified gate voltage equals the threshold voltage plus x volts, where x is in the range of 100 mV to 4 V, and
• wherein when the first converter is in the short circuit state, the DC link voltage is less than the DC link voltage used during a normal switching operation.