Development of Compact SMPS and Its Reliability Study

Abstract

n any electrical drive consisting of 3-leg inverter or converter, a control circuit power supply and driver section power supply must be isolated from each other. In this thesis, Switched Mode Power Supply (SMPS) with multiple outputs is developed which satisfies this need of an electrical drive. Developed SMPS generates multiple outputs for control circuit power supply and driver section power supply and also gives isolation between them and hence, there is no need of extra components for isolation. Fly-back converter topology is selected due of its advantages over other basic topologies of SMPS. Effects of parasitic elements like Transformer and MOSFET are also discussed and different solutions to reduce their effects are also discussed and one of them is used for the developed SMPS. Open-loop simulation is carried out in PSPICE software and results are shown. Hardware developed is employed in closed -loop and Current Mode Control methods. SMPS developed consumes a power of upto 30 W and generates supply output voltages of + 5 V; ± 15 V, 24 V for control circuit; + 24 V for fan supply (isolated) and four + 24 V supplies all isolated from each other for driver circuit. Polarity Check Test, High Voltage Test and Short Circuit Test are also discussed and carried out for SMPS and hardware results are tabulated for change in output voltage with change in input voltages, hardware waveforms for output voltage ripple waveforms and driver circuitry output voltages to be given to IGBT.

In this report, Reliability Study basics and two methods for carrying out Reliability Analysis are incorporated. For given components list of an SMPS, Reliability Study is carried out using Part Count method.