AN2383 datasheet(30/39 Pages) STMICROELECTRONICS

30 / 39 page

Thermal conditions

AN2383

30/39

Doc ID 12433 Rev 3

Thermal conditions

The induction cooking system described in this document can deliver up to 2500 W at its

maximum working level.

The IGBTs need to be mounted on a heatsink, as does the power diode bridge.

Tests performed in laboratory conditions demonstrate that even when delivering the

maximum power for a long duration, the temperature of the components does not exceed

the safe working area. The board was placed in an open space without an enclosure.

In a real application, the board would be placed inside a box. And, to save space, the plate

is usually placed over the circuitry. Therefore, the heat dissipated by the heatsink has no

easy way out, and the cooking process worsens the thermal conditions. The heatsink is no

longer sufficient to dissipate the heat. For this reason, a fan is implemented in the system

which is driven directly by the MCU.

Tests have demonstrated that while delivering the maximum power, the temperature

reaches a stable value below 90 °C, which can still be considered safe.

The fan starts as soon as the temperature on the heatsink reaches 55 °C. The fan stays on

for at least one minute, whether the system is on or in standby mode.

Fan management can be modified by software. An NTC mounted directly on the heatsink,

between the IGBTs, improves control efficiency. Working as a thermostat controlled by an

MCU, the sensor turns the fan on or off when necessary.

Any increase in the induction cooking system performance (for example, if higher output

power is required), would result mainly in adapting the cooling system, resizing the heatsink,

using a more powerful fan, or all three.

The system itself is capable of handling up to 3000 watts of power.

AN2383 датащи(PDF) 30 Page - STMicroelectronics