Series intermediate frequency furnace
The series one-to-two intermediate frequency furnace adopts thyristor fully controlled rectifier bridge. In the series resonant power supply, the rectifier thyristor is always in a fully open working state under any circumstances, so it ensures the stable DC voltage output and does not reduce the power factor. And increase the harmonic content.
When the power supply fails or alarms, the thyristor fully controlled rectifier bridge is equivalent to a solid-state control switch, which will immediately cut off the main circuit and provide the most effective protection for the main components of the power supply.
The series intermediate frequency furnace has the following advantages:
(1) Strong load adaptability. Whether the intermediate frequency furnace is cold, hot, half-charged or full-charged, the series inverter can output rated power. That is to say, in the whole melting process, the series inverter always works in the rated output state. Therefore, the utilization rate of the equipment can be improved, the melting speed can be accelerated, and the energy consumption can be reduced.
(2) The series intermediate frequency furnace inverter adopts the method of changing the operating frequency to adjust the output power. It only needs a fixed DC voltage for power supply. Therefore, two series inverters can share a set of rectified power supply to achieve bidirectional power supply. This is a true two-way power supply system. Two electric furnaces get power at the same time, without any switch to switch between the electric furnaces. On the two electric furnaces, the power can be adjusted arbitrarily within the range of 0% -100%.
Series intermediate frequency furnace inverter group is composed of fast thyristor KK tube, fast recovery diode ZK, buffer module, control system, compensation capacitor group, each with a furnace body. The use of large-section water-cooled copper bars ensures less energy loss;
A set of fast thyristor KK tube for series resonant inverter is composed of several groups of modules with the structure shown in KK1 and KK2 connected in parallel. The trigger signal uses centralized trigger pulses, which has good consistency and ensures controllability on the same bridge wall Silicon is turned on and off at the same time;
Trigger control system also has protection against simultaneous conduction of upper and lower bridges;
Each KK tube also has a fast recovery diode to provide bypass for the overvoltage and load generated when the thyristor is turned on to be turned off by the back pressure;
Each group of devices has a current-limiting inductor at the front end string to suppress the current rise rate and protect the thyristor's safe operation