A Medium-Voltage Magnetic Component Testing System
Authors
Petersen, Frederik Hjortkær ; Chaudhary, Hijab
Term
4. term
Education
Publication year
2021
Submitted on
2021-05-27
Pages
51
Abstract
Transformers are widely used and must be tested to ensure they operate safely under real conditions. This thesis develops and evaluates a laboratory test system that reproduces real operating conditions for high-frequency transformers. Several converter topologies are reviewed, and an extended Dual-Active Bridge (DAB) is chosen as the core of the system. In a DAB, two actively switched converters are linked through a transformer, and power flow is controlled by a timing difference (phase shift) between their gating signals. In the extended DAB, power is circulated between the primary and secondary to reduce the power drawn from the supply, and the effect of this circulating path is examined. The system is modeled and simulated in PLECS Standalone. The main adjustable parameters—switching frequency, phase shift, and duty cycle—are varied in open loop to study their influence on transformer operating conditions. A closed-loop controller is then derived to regulate transformer current by adjusting the phase shift. Both simulations and experiments use a single phase shift between the primary and secondary converter gating signals. The system is built in the laboratory and controlled using a PLECS RT Box 1 and PLECS Coder. System performance is assessed, and conclusions are drawn primarily from the closed-loop simulation results.
Transformere er udbredte og skal testes, så de kan fungere sikkert under de forhold, de møder i praksis. Dette arbejde udvikler og vurderer et laboratoriebaseret testsystem, der efterligner virkelige driftsforhold for højfrekvente transformere. Flere konvertertopologier skitseres, og en udvidet Dual-Active Bridge (DAB) er valgt som kernen i systemet. I en DAB er to aktive konvertere forbundet via en transformer, og effektstrømmen styres ved at forskyde timingen (faseforskydning) mellem deres styresignaler. I den udvidede DAB cirkulerer effekt mellem primær- og sekundærsiden for at reducere den nødvendige effekt fra forsyningen, og virkningen af denne cirkulerende vej undersøges. Systemet modelleres og simuleres i PLECS Standalone. De vigtigste indstillinger—koblingsfrekvens, faseforskydning og duty cycle (tænd/sluk-forhold)—variere i åben sløjfe for at se, hvordan de påvirker transformeren. Derefter udledes en lukket-sløjfe-regulering, der styrer transformerstrømmen ved at justere faseforskydningen. Både simuleringer og forsøg anvender en enkelt faseforskydning mellem primær- og sekundærkonverterens styresignaler. Systemet bygges i laboratoriet og styres med PLECS RT Box 1 og PLECS Coder. Systemets ydeevne vurderes, og konklusioner drages primært på baggrund af resultaterne fra lukkede-sløjfe-simuleringer.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords