电磁炉有关IGBT的翻译

IGBT Selection Method for the Design of Resonant Inverters for DomesticInduction Heating

Abstract

The power transistor (IGBT) is one of the most important components of the inverter of domestic induction cookers. For this application the maximum junction temperature (Tjmax) of the IGBT is one of the most critical design parameters because the cooker has to decrease the output power when the junction temperature is near to Tjmax of the device. The junction temperature (Tj) of the IGBT principally depends on the power losses. This paper proposes a method to choose the IGBT based on the calculation of the temperature variation ΔTja from the power losses.

Nowadays, IGBT behaviour is a trade-off between conduction and switching performance, so it is necessary to measure the IGBT power losses separately. This paper proposes a method to measure the power losses separately based on electrical measurement and the IGBT conduction characteristics. Moreover it is proposed a criterion to determinate the limits of the power losses based on eliminate theoffset of device voltage and the switching area is defined from the voltage is over 2.5 V to the current is zero.

Finally, the proposed method has been applied to five different IGBTs for different levels of power and with two standard pans with an electronic board of a commercial cooker Moreover this method has been verified with a thermografic camera obtaining similar results.

Introduction

Domestic induction cookers take the energy from the mains voltage, which is rectified and filtered. Then the resonant inverter supplies high-frequency current to the induction coil. The half-bridge series resonant inverter (Fig. 1 (a)) is the most used due to the electrical requirements of its components, its simplicity and its cost-effectiveness [1]. The resonant load consists of the pan and the induction coil. Their coupling is modelled as the series connection of an inductor and a resistor, based on the transformer analogy [2].

Domestic induction cookers enable to heat the pan in a power range between 3300 W and 50 W. The modulation strategies typically used in domestic induction heating are the Square Wave (SW) control and the Asymmetrical Duty Cycle (ADC) control for the high power range and the Pulse Density Modulation (PDM) [3] for the low power range.

One of the most important components of domestic induction cookers is the power transistor; usually it is an IGBT for its conduction and switching characteristics. For this application the maximum junction temperature (Tjmax) of the IGBT is one of the most critical design parameters because the cooker has to decrease the output power when Tj is near to Tjmax of the device. This reduction of the output power is not desirable for this application, so the optimum IGBT is that one minimizes this reduction of power

The junction temperature (Tj) of the IGBT depends on the power losses, the cooling system, the thermal characteristics of the device and the environment temperature (Ta). The refrigeration system consists of the isolation foil, the heatsink and the fan