Generelized approach for calculating electrical losses in semiconductor devices

摘要

Electrical losses in semiconductor devices are key to their normal operation. In essence, they take into account the heat losses in the load, which is estimated by the amount of the average active power dissipated there. The latter includes the following components: turn-on state losses, turn-off state losses, switching on losses, switching off losses and losses in controlled junction. Usually, in practice last four types losses are negligible and they can be eliminated. In turn, the average active power is in a proportion to the square of the shape coefficient and depends on the average value of the current flowing through the load in the form of a square function.In the present paper an analytical expressions about these two quantities for all analyzed semiconductor devices are established. A single and a pair of two Insulated-Gate Bipolar Transistors (IGBT) are discussed.Corresponding dependences between the average value of the consumed active power in the load and a firing angle α and a slake angle β of an IGBT have been worked out. An optimal correlation condition between these two angles is proposed. At the end of the article, recommendations regarding the limitation of the values of this power are given. This is necessary in order to prevent overheating of the semiconductor crystal, which leads to its breakdown.