by Teardown of a 8 kW induction cooktop, supplied from 2 single phase mains and neutral. Modular construction with two inverter modules and changeable coils. To get a full explanation on Quasi-Resonant induction heaters, check out my teardown and hacking videos on the IKEA Tillredda induction stoves.
Induction Heater Coils
The induction stove coils are almost all identical and the differences in the size of each cooking zone is purely done in software or configuration on the PCB. Coils are made from litz wire in insulating foam and heat reflecting materials. This is to avoid heat from the pan heating up the coils, which struggle enough with heat from skin effect losses and proximity effect.
Induction heater inverter
The 8 kW induction stove inverters are two separate modules which each has two cooking zones. Each module has a common input, noise filter and bridge rectifier. Each cooking zone and induction coils is connected to separate half-bridge inverters which uses 4 uF of DC bus capacitance and two 0.68 uF / 800 VDC 50 kHz resonant capacitors.
8 kW Induction Cooktop Parts
First the input bridge rectifier is a Chinese brand model D25XB60, which is a 25 A at 600 V rectifier diode. Secondly the IGBT is a Toshiba GT60J323 in a TO-3P package. The IGBT is rated for 33 A continues current at 600 V or 120 A pulsed current. To learn more about power electronics and discuss high voltage and high current experiments, visit the High Voltage Forum.
Thirdly the controller that is used on all printed circuit boards is a ST Microelectronics ST72325 8 bit microcontroller. This had built in Flash/ROM, ADC, timer, SPI, SCI and I2C interface. All the controllers are therefor most likely communicating over I2C and not CANBus as mentioned in the video.
