AC Electronic Load for testing of a SONAR Power Amplifier

The SONAR (Sound Navigation and Ranging) system is a popular technique for the underwater surveillance used in submarines. A piezoelectric-based transducer is the heart of the SONAR system to produce acoustic waves for object detection in the underwater. Moreover, the transducer resembles a reactive element in which the power factor angle varies from ±60°. A power amplifier with a frequency ranging from 500 Hz to 10 kHz is used to power the transducer. Testing of these power amplifiers at different operating conditions is an essential procedure to ensure the reliability of operation. As of the date, the available electronic load bank has a restriction in operation of 0 Hz to a few Hz and is not suitable for the high-frequency application. Therefore, in this work, a configurable AC electronic load with a frequency ranging from 500 Hz to 2000 Hz will be realized to test the power amplifier under different power factor conditions. Parallel connections of R, L, and C elements are properly designed and emulated to create the phase angle and impedance that varies from 250 Ω to 1250 Ω at ±60°. To each branch, a four-quadrant switch is connected to obtain the above-mentioned variation at frequencies of 500 Hz to 2000 Hz. Further, a simple genetic algorithm is used to realize a switch combination as per the selected range of frequency, impedance, and phase angle. The complete system is validated through a 1 kW test system developed in MATLAB Simulink.