The power regulation of the silicon-controlled rectifier (SCR) parallel induction heating equipment is achieved by adjusting the conduction angle of the rectifying SCR. When the equipment operates at low power, the conduction angle of the SCR decreases, resulting in a lower power factor of the grid. Therefore, it is necessary to install a power factor compensation cabinet to increase new investment. Without installing a power factor compensation cabinet, it could lead to capacitor damage in the user's power distribution room's compensation cabinet or overheating of the power supply transformer. This would increase the user's investment and result in power loss. The power regulation of the IGBT series induction heating equipment uses inverter-side regulation, with the rectifying circuit employing diodes. The power factor of the rectification is 100%, so no additional equipment needs to be configured in the distribution cabinet.
2. During the operation of the IGBT series induction heating equipment, the reverse voltage the switching devices endure is very small, merely the conduction voltage drop of the reverse-parallel diodes of the switching devices. It is extremely low. When the silicon-controlled rectifier parallel power supply is operating, the switching devices bear a higher reverse voltage. Due to the low capability of the self-switching devices IGBT to withstand reverse voltage, it is necessary to connect fast-recovery diodes with equal capacity in series with the main switches of each bridge arm in application, which increases the losses. Aviation ground power 2, 36V aviation power supply 1, 400Hz variable-frequency power supply 7, 115/200V power supply 2, 27V DC power supply 5, 400Hz power supply 12, aviation power supply.
3. The inverter input of the IGBT series induction heating equipment is equivalent to a constant voltage source, with the load being a series combination of R, L, and C. Its output voltage is a rectangular wave, and the current is an approximate sine wave. The IGBT in this setup withstands rectangular voltage, resulting in a large dt/du, making the absorption circuit crucial, while the requirement for dt/di is relatively low. The inverter input of the SCR parallel power source is equivalent to a constant current source, with the load being a parallel combination of R, L, and C. Its output current is a rectangular wave, and the output voltage is an approximate sine wave. The IGBT in this system withstands rectangular current, with a large dt/di. Sometimes, to reduce dt/di, an inductor must be串联 in the circuit to limit dt/di, which increases losses.
