Thyristor starter

A thyristor starter for starting a synchronous machine having a rotor having a field winding and a stator, comprising:

• a converter that converts AC power into DC power;
• a DC reactor that smooths the DC power;
• an inverter that converts the DC power applied from the converter through the DC reactor into AC power with a variable frequency, and supplies the AC power with the variable frequency to the stator;
• and
• an exciter that supplies field current to the field winding, wherein
• the thyristor starter accelerates the synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode and a second mode, the first mode performing commutation of the inverter by intermittently setting DC output current of the converter to zero, and the second mode performing commutation of the inverter by induced voltage of the synchronous machine, and
• the thyristor starter further raises the induced voltage in proportion to a rotation speed of the synchronous machine by keeping the field current constant, and suppresses a rise of the induced voltage by reducing, in the first mode, the field current, after the induced voltage reaches a first voltage value.