High power linear AC Electronic Load for testing UPS Systems

Abstract

Concept of a series bipolar transistor array for AC power control is already developed. However non-linearity issues, high power capability with load sharing at high voltages and digital control with better transient performance were not adequately adopted in early-developed stages.

This thesis is a description of the design approach of digitally controllable linear 230V/50 Hz AC line voltage capable electronic load with predictable characteristics based on spice simulation. The BJT array used in this project provides high power dissipation capability and uniform voltage and power distribution across the individual transistors. A set of optoisolators are used to have electrical isolation between power stage and digital control circuits. A Zilog Z8Encore! 64K series development kit is used in controlling the circuit.