Transformers are one of the most widely used electrical equipment in power distribution and electronics systems. As these applications require the components to fulfil the system operating conditions, the transformer needs to be tested. This report focuses on a testing system that emulates real-life conditions for high-frequency transformers.
Different topologies are described, and an extended Dual-Active Bridge (DAB) has been chosen for implementing the testing system. To drive the DAB, different switching topologies are investigated. The simulations and experiments are performed with a single phase-shift between the primary and secondary converter's gating signals. In the extended DAB, the power circulates between the primary and the secondary to minimize the power required from the power supply. The effect on the circulating path is investigated. The system is modelled and simulated in PLECS Standalone. In the system, the controllable parameters are the switching frequency, the phase-shift and the duty cycle. The influence of these parameters to the transformer conditions are investigated by open-loop simulations. Then, closed-loop control of the phase-shift is derived to control the transformer current. The control is applied to the simulations and the experimental setup. The system is constructed in the laboratory and controlled using a PLECS RT box 1 and PLECS Coder. Based on the simulation results of the closed-loop controller, a conclusion is made of the testing system performance.