Current Control and Loss Estimation in a Medium Voltage Silicon-Carbide Power Converter
Authors
Kirkeby, Mathias ; Nielsen, Morten Rahr
Term
4. term
Education
Publication year
2022
Submitted on
2022-05-30
Pages
112
Abstract
Wide bandgap materials, such as silicon carbide (SiC), are gaining traction in power electronics because they can handle high voltages and temperatures and switch quickly, reducing losses. This thesis demonstrates closed-loop current control in a 10 kV SiC MOSFET-based half-bridge power converter. To limit the impact of switching noise on the current feedback signal, the sampling scheme proposed in [1], [2] is implemented and shown to work in practice. A single-phase proportional–resonant (PR) current controller is designed and deployed on a DSP control board within a single-phase back-to-back experimental setup. The controller includes dead-time compensation based on a linear approximation built from measurements of the actual dead-time voltage error during switching transients at different load currents. With the controller in place, the setup functions as a test platform to evaluate power module performance in terms of losses and MOSFET die temperatures during operation. It is tested across various DC-link voltages, load currents, and switching frequencies. Experimental results are compared to expected values derived from conduction losses calculated from on-state resistance and switching losses estimated from a double-pulse test in [3].
Materialer med bredt båndgab, som siliciumcarbid (SiC), vinder frem i effektelektronik, fordi de kan håndtere høje spændinger og temperaturer og skifte hurtigt, hvilket kan reducere tab. Denne afhandling demonstrerer lukket-sløjfe strømkontrol i en 10 kV SiC MOSFET-baseret halvbro-strømomformer. For at mindske påvirkningen af koblingsstøj på strømfeedback er den i [1], [2] foreslåede prøvetagningsmetode implementeret med succes. En enfaset proportional-resonant (PR) strømkontroller er designet og implementeret på et DSP-styrekort i en enfaset back-to-back forsøgsopstilling. Kontrolleren omfatter en dead time-kompensation baseret på en lineær approksimation af de målte spændingsfejl, der opstår under koblingstransienter for forskellige laststrømme. Den vellykkede implementering gør opstillingen til en testplatform til at evaluere effekttab og MOSFET-dietemperaturer under drift. Dette er eksperimentelt afprøvet ved forskellige DC-link spændinger, laststrømme og koblingsfrekvenser. De målte resultater er sammenlignet med forventede værdier afledt af ledetab beregnet ud fra on-state modstand samt koblingstab baseret på en double-pulse test udført i [3].
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords