High-frequency lamp simulator for testing electronic ballasts

A high-frequency lamp simulator for testing the startup and steady-state behaviors of electronic ballasts is presented. It can simulate the behaviors of a fluorescent lamp before, during and after ignition. The main power processing stage (PPS) of the simulator consists of a high-frequency series-resonant AC/DC converter. The electronic ballast under test is connected to the AC side of the PPS through an L-C-L filter. The equivalent input impedance on the AC side of the PPS is adjusted by controlling the magnitude of the voltage on the DC side of the converter, and phase difference between the voltage on the ac side of the converter and ballast output. It can be controlled to be very large to simulate the lamp behavior before ignition. When the simulator is used to simulate the behavior of a lamp after ignition, the output current of the ballast is controlled to be in phase with its output voltage, so that the equivalent input impedance on the Ac side of the simulator is resistive, simulating the high-frequency characteristic of a fluorescent lamp. A 24 W prototype that can simulate the behaviors of a T8 fluorescent lamp has been tested and evaluated. The experimental results are in close agreement with the theoretical predictions.