Loss measurement in semiconductor rectifier equipment

IT HAS long been recognized that the efficiency of a large rectifier unit cannot be determined accurately by input-output power measurements. The “segregated loss” method has been written into rectifier standards because it reduces greatly the errors inherent in input — output measurements of high-efficiency equipments. However, when determining the losses of the semiconductor rectifier itself, we must take into account the difference of wave shape of the cell currents in normal operation and in the test circuit. The high incremental resistance of the cells precludes the direct equation of losses for the same average currents at different form factors.