An accurate way of determining BJT´s switching loss in medium and high voltage applications

Semiconductors are widely used in power electronics applications as a switching device. In some applications, BJTs are used and their power loss calculation has a crucial effect on the temperature performance of transistors which must be in thermal limits. The power loss can be analyzed in three states; on, off and transition. In recent studies, on state loss has been calculated by estimation. In addition to that, in higher voltage applications, it is difficult to measure collector-emitter voltages (V_CE) to calculate on and transient state losses correctly due to tolerances of voltage probes. An accurate power loss calculation method of BJT devices has been presented in this research in which the losses are evaluated by measuring only the base (I_B) and the collector currents (I_c) without any estimation. The method does not require collector-emitter voltage measurements. The proposed method has been experimented on a current fed push-pull resonant inverter.