High-Bandwidth High-CMRR Current Measurement for a 4.8MHz Multi-Level GaN Inverter AC Power Source
Metadata only
Datum
2021Typ
- Conference Paper
Abstract
The control of very high switching frequency power electronic converter systems featuring latest generation wide bandgap (WBG) devices requires current measurements with a very high bandwidth (BW) to achieve high closed-loop control dynamics. One example is a ultra-high BW 4.8 MHz parallel-interleaved multi-level GaN inverter AC power source with a target output BW of 100 kHz. This work investigates the combination of state-of-the-art Hall-effect current sensors with a suitable high-frequency (HF) sensor to extend the BW of the commercially available current sensor by a factor of 20 50, i.e., up to 10 20 MHz. The main focus lies on a small form factor and a low realization effort. HF current sensors based on a Rogowski coil, an inductor integrated voltage sensing and a current transformer (CT) are analyzed and compared. Additionally, their respective performance limitations are highlighted. Furthermore, a precise combiner network to combine the low-frequency (LF) and HF signal is analyzed. The combiner circuit is designed in a way that component tolerances have no influence on the behavior in the transition frequency range from LF to HF. Thereby, also the immunity to Common-Mode (CM) disturbances, i.e., the high dv/dt occurring for the switching transitions of WBG semiconductors is considered. Finally, a hardware demonstrator featuring the two most promising current sensor approaches, i.e., the inductor voltage sensing and the CT, is presented and verified with comprehensive measurements in frequency and time domain. A BW from DC up to 35 MHz is measured. The realized sensors are further tested with a hardware prototype of the aforementioned AC power source switching 600 V at an effective switching frequency of 1:6 MHz. The measurements clearly reveal that both proposed sensor concepts are well suited for accurate measurements in fast switching converter systems with negligible additional volume. Mehr anzeigen
Publikationsstatus
publishedExterne Links
Buchtitel
2021 IEEE Applied Power Electronics Conference and Exposition (APEC)Seiten / Artikelnummer
Verlag
IEEEKonferenz
Thema
Current Measurement; Hall Sensor; Rogowski Coil; Current Transformer; Inverter; Wide Bandgap Semiconductors; Multi-Level Converter; Ultra-High Bandwidth DC/AC ConverterOrganisationseinheit
03573 - Kolar, Johann W. (emeritus) / Kolar, Johann W. (emeritus)