Thyristor starter

A thyristor starter that starts a synchronous machine, the thyristor starter 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 supplied from the converter through the DC reactor into AC power of a variable frequency and supplies the AC power to the synchronous machine;
• and
• a controller that controls a firing phase of a thyristor in the converter such that a direct current flowing through the DC reactor coincides with a current command value, wherein
• the thyristor starter accelerates the synchronous machine in a stopped state to a prescribed rotation speed by sequentially adopting a first mode and a second mode,
• in the first mode, the thyristor starter performs commutation of the inverter by intermittently setting the direct current to zero, and
• in the second mode, the thyristor starter performs commutation of the inverter by an induced voltage of the synchronous machine,
• the controller includes
• a current controller that generates a voltage command value for an output voltage of the converter by performing a control operation using an integral element of a deviation of the direct current with respect to the current command value,
• a corrector that adds a correction value to the voltage command value, and
• a control angle calculator that calculates a phase control angle of the thyristor in the converter based on the voltage command value to which the correction value is added, and
• in the first mode, the correction value is set to increase as a rotation speed of the synchronous machine increases.