Identyfikacja warunków pracy transformatorów zasilających przekształtniki AC/DC/AC

The upshot of the ongoing development of energy-transforming systems is that devices used In power engineering meet with more difficult operating conditions when they co-operate directly with Power electronics circuits. High efficiency of power electronics circuits is achieved by switching power electronics elements on and off, often it is accomplished with PWM modulation. This approach causes emergence of very fast voltage gradients in the circuit, occurring at switching frequency. This may in turn adversely affect some elements of energy-transforming systems. We find such circuits in case of electric motors supplied from Power electronic converters, power electronics circuits for battery chargers, power electronics circuits used to trans form ecological energy obtained e.g. from solar batteries. We may cite here the example of inverters supplying induction motors; using inverters forced manufacturers to increase insulation level in these motors. Similar problem is encountered in case of using standard power engineering transformer in the circuit with Power electronics supply. The conducted tests of transformer oil show that after c. 5 years operation the oil had deeply degraded and this bears negative impact on insulation quality and significantly threatens transformer's life time.