A Simple Variable THD Load Emulation Technique for Performance Evaluation of Power Supply Equipment

Using load emulation, the performance of source side converters can be easily evaluated and improved without the need for actual load. Due to the increase in use of power electronic converters and SMPS based systems, the harmonic levels in load side has increased considerably. Hence emulation of variable THD load is very important in analysing the performance of source side converters and ensure the performance efficiency and power quality under such loads. Here a novel method of obtaining variable load using PWM control explained. The PWM is controlled in a rainbow sinusoidal fashion to obtain clipped waveform across a resistor so that harmonics is introduced in the Load. The power factor can also be varied in the system by paralleling it with leading and lagging converter circuits. The working principle, modelling and simulation are presented along with the results. Proposed technique provides accurate modulation of load THD and effect of harmonics loads on sources converter are also analysed using this.