Design and testing of a power electronic synthetic inductor

In many applications inductors are often replaced with circuits, typically based upon operational amplifiers, which emulate an inductance for reasons of package size or to closer approximate the desired ideal behaviour. A power electronic synthetic inductor offers an alternative circuit which can emulate an inductor with relatively low power consumption, as well as provide a flexible circuit topology that is not limited to inductive behaviour. In this article, a power electronic synthetic inductor topology and control system is developed. A prototype synthetic inductor was built and tested, and its operation was explored and compared with an operational-amplifier-based synthetic inductor. A minor modification of the circuit allows the emulation of a negative resistance in parallel with the synthesised inductor, which can increase the quality factor of the system beyond that associated with an ideal inductor. Experimental results reveal that the power electronic synthetic inductor has significantly lower power consumption than an operational-amplifier-based synthetic inductor.