• Mike Robin Zäch
  • Simon Holt Olsen
  • Janus Dybdahl Meinert
  • Benjamin Futtrup Kjærsgaard
  • Sigmundur I Gardi
1. term, Energy Engineering, Master (Master Programme)
Bootstrap circuits are commonly used as gate driver power supplies to get rid of isolated DC/DC supplies. This allowsfor a smaller and cheaper circuit powering the gate driver. However, a bootstrap circuit limits the operational dutycycle for the converter as the bootstrap capacitor needs a certain time to charge during each switching period [12]. Theestimation of the duty cycle has previously been done by “rule of thumb”, which resulted in an underestimation of theduty cycle limit. By taking the output current and on-state resistance into account, the accuracy of these estimations isimproved, leading to the possibility of using higher modulation index, lowering the DC link voltage and thereby reducingswitching losses. In this paper, a test setup is designed which consists of two half-bridges connected through an inductiveload as a single-phase back-to-back converter. Leg 1 is controlled by open loop control which fixates the modulationindex, while the load current is controlled using a PR controller on leg 2. Using this converter configuration, it is possibleto operate with a known modulation index on leg 1 containing the bootstrap circuit, and with a controlled load currentto validate the proposed method [1].
SpecialisationPower Electronics and Drives
Publication date15 Dec 2019
Number of pages58
ID: 317390783