The one-to-two intermediate frequency furnace adopts the "series inverter type thyristor intermediate frequency power supply technology". Although the thyristor fully controlled rectifier electric furnace is used, it does not use it for voltage regulation. It only uses it to achieve soft start and act as an electronic switch in the event of a fault to quickly cut off the power supply. , In normal operation, the thyristor is always in the fully-on state, so that the power supply of the grid has a high power factor and reduces harmonic interference. The rectifier control circuit adopts a digital shift trigger circuit. The digital shift trigger circuit has the advantages of good repeatability, good stability, good symmetry, strong anti-interference ability, and convenient debugging. If the digital quantity setting is used, it can still realize remote control.