Two papers at the European Conference on Power Electronics and Applications
The paper entitled “Fast Voltage Stabilization Control of Split DC Bus Midpoint in 3P4W Shunt APFs” and the paper entitled “An isolated bidirectional half-bridge active-clamp current-fed push-pull DC/DC converter for DC microgrid applications” has been published in the proceedings of the 21st European Conference on Power Electronics and Applications (EPE ’19 ECCE Europe)!
The first paper proposed a midpoint voltage balancer (MVB) based on dual-switching-leg. The MVB provides fast voltage stabilization of the midpoint in three-phase four-wire (3P4W) shunt active power filters (APFs). Interleaved control is adopted in the MVB to prevent high-frequency current circulation in split capacitors, and to facilitate an accurate neutral current tracking. All switches of the MVB operate in zero-voltage switching (ZVS) mode when the neutral current is smaller than the nominal phase current of the APF. MATLAB simulation is carried out to verify the effectiveness of the MVB. A 20 kVA prototype has been built, and experimental results show that the voltage ripple of the midpoint is maintained within 1.5% of the total dc bus voltage even under severe neutral current transient.
The second paper describes an isolated bidirectional half-bridge active-clamp current-fed push-pull DC/DC converter developed for a DC microgrid. A novel modulation scheme is introduced for step-down operation, which decreases the switching losses mainly on the higher voltage side of the converter. Also, the effect on step-up operation mode is analyzed in detail. A prototype of the converter is built with a nominal output power of 600 W exhibiting a peak efficiency of 96.8% in step-down operation. Measurements show a good agreement with the simulated key waveforms. The topology has also a highly efficient step-up operation mode with a peak efficiency of 96.2%.