Jordi Everts

• Dr. MSc.
• Technology Manager at Neways Technologies

Non-isolated three-phase AC/DC converter concepts facilitate more compact and more efficient realizations of future EV chargers. However, without the galvanic isolation and/or high common-mode (CM) impedance provided by an isolation transformer, non-isolated chargers must employ other means to suppress CM leakage currents to ground sufficiently and...

Single-phase Power Factor Correction (PFC) rectifiers with sinusoidal grid currents are inherently subject to an input power fluctuating at twice the mains frequency. In order to potentially mitigate bulky, heavy and failure-prone electrolytic dc-link capacitors, active Power Pulsation Buffer (PPB) concepts are proposed in the literature. For conve...

The modulation strategy proposed in this paper enables wide-range zero voltage switching (ZVS) operation of a three-level three-phase dual active bridge (DAB) dc-dc converter. The circuit topology is analyzed and piece-wise linear equations are derived for most appropriate switching modes. Based on the results of a numerical optimizer a modulation...

A directly employable closed-form analytical solution for the calculation of an efficient, full-operating-range zero voltage switching (ZVS) modulation scheme for bidirectional dual active bridge (DAB) dc–dc converters is presented. Contrary to the analytical ZVS modulation schemes previously proposed in literature, the amount of charge that is req...

This paper investigates a three-level three-phase Dual Active Bridge (DAB) dc-dc converter with a star-delta connected transformer. The soft-switching region is analyzed for two and three-level operation, using symmetrical voltage waveforms, showing an increased ZVS range for three-level operation. A large number of switching modes are identified a...

The growing attention on plug-in electric vehicles, and the associated high-performance demands, have initiated a development trend towards highly efficient and compact on-board battery chargers. These isolated ac-dc converters are most commonly realized using two conversion stages, combining a non-isolated power factor correction (PFC) rectifier w...

An advanced charge-based Zero-Voltage Switching (ZVS) modulation strategy for a Flying Capacitor Resonant Pole Inverter (FC RPI) with trapezoidal filter current is presented, resulting in full operating range ZVS, decreased rms value of the circulating filter current, and increased switching frequency. A charge-based model that correctly incorporat...

This paper analyzes a three-phase Dual Active Bridge (DAB) dc-dc converter with three-level phase-legs,showing a significant increase in the soft-switching region compared to two-level operation. A strategy is presented that results in a Zero Voltage Switching (ZVS) modulation scheme that relies on analytical equations, uses a small amount of switc...

A three-phase dual active bridge (DAB) converter with three-level phase-legs is analyzed, showing an increased soft-switching region and a reduction in rms current in the ac-link for unequal input and outputvoltages compared to the conventional two-level circuit. Furthermore, a comparison of the semiconductor losses is carried out for different thr...

The growing attention for plug-in electric vehicles, and the associated high-performance demands, have initiated a development trend towards highly efficient and compact on-board battery chargers. These isolated ac-dc converters are most commonly realized using two conversion stages, combining a non-isolated power factor correction (PFC) rectifier...

This paper provides an analysis of a three phase dual active bridge (DAB) topology used as high-power-density dc-dc converter for railway applications. The three-phase DAB is analyzed concerning the current intervals, the output power and soft-switching region, including the impact of zero-voltage switching (ZVS) capacitors. Furthermore, two measur...

This paper investigates the impact of three transformer-winding configurations, i.e. the Y-Y, the Y-Δ, and the Δ-Δ configuration, on the performance of a three-phase dual active bridge (DAB) dc-dc converter. For each configuration, equations for the phase current, power flow, and soft-switching boundaries are derived for all possible switching mode...

This paper is divided into three main parts. In the first part, i.e. Section II, a general outline of the system level aspects regarding battery chargers (power converters) for plug-in electric vehicles (PEVs) is given. Thereby, the different charging modes of the converters, the corresponding power levels, and the infrastructural facilities are di...

This paper investigates the impact of three transformer winding configurations, i.e., the Y-Y, the Y-Δ, and the Δ-Δ configuration, on the performance of a three-phase dual active bridge (DAB) dc-dc converter. For each configuration, equations for the phase currents, power flow, and zero-voltage switching (ZVS) boundaries are derived for all possibl...

A comprehensive procedure for the derivation of optimal, full-operating-range zero voltage switching (ZVS) modulation schemes for single-phase, single-stage, bidirectional and isolated dual active bridge (DAB) ac–dc converters is presented. The converter topology consists of a DAB dc–dc converter, receiving a rectified ac line voltage via a synchro...

A semi-analytical modulation scheme to operate a single-phase, single-stage dual active bridge (DAB) AC-DC converter under full-operating-range zero voltage switching (ZVS) is proposed. The converter topology consists of a DAB DC-DC converter, receiving a rectified AC line voltage via a synchronous rectifier. ZVS modulation strategies previously pr...

For determining the dynamic on-resistance Rdyn,on of a power transistor, the voltage and current waveforms have to be measured during the switching operation. In measurements of voltage waveforms, using an oscilloscope, the characteristics of an amplifier inside the oscilloscope are distorted when the range of the measurement channel is not set wid...

A switching control strategy to enable Zero-Voltage-Switching (ZVS) over the entire input-voltage interval and the full power range of a single-stage Dual Active Bridge (DAB) AC/DC converter is proposed. The converter topology consists of a DAB DC/DC converter, receiving a rectified AC line voltage via a synchronous rectifier. The DAB comprises pri...

For realizing bidirectional and isolated AC/DC converters, soft-switching techniques/topologies seem to be a favourable choice as they enable a further loss and volume reduction of the system. Contrary to the traditional dual-stage approach, using a power factor corrector (PFC) stage in series with a DC/DC isolation stage, we showed recently that t...

III-Nitride materials are very promising to be used in next-generation high-frequency power switching applications. In this letter, we demonstrate the performance of normally off AlGaN/GaN/AlGaN double-heterostructure FETs (DHFETs) using a boost-converter circuit. The figures of merit of our large (57.6-mm gate width) GaN transistor are presented:...

A switching control strategy to extend the zero-voltage-switching (ZVS) operating range of a Dual Active Bridge (DAB) AC/DC converter to the entire input-voltage interval and the full power range is proposed. The converter topology consists of a DAB DC/DC converter, receiving a rectified AC line voltage via a synchronous rectifier. The DAB comprise...

A boost converter was constructed using a high voltage enhancement mode (E-mode) AlGaN/GaN/AlGaN DHFET transistor grown on Si<;111>. The very low dynamic onresistance (R_dyn ≈ 0.23 Ω) and very low gate-charges (e.g. Q_gate ~15 nC at Vos = 200 V) result in minor transistor losses. Together with a proper design of the passive comp...

Wide-bandgap (WBG) semiconductors, such as gallium nitride (GaN), are more and more being used in switching power devices. An AlGaN/GaN/AlGaN Double Heterojunction Field Effect transistor (DHFET) was developed in previous work and needed to be tested. The used test circuit was a buck converter. This type of converter, in addition with the normally-...

Gallium Nitride (GaN) is increasingly considered a viable semiconductor material in future power electronic converters. The benefical properties of GaN, being the result of its wide bandgap and the possibility to form heterostructures, make a further optimization of the power conversion possible. Although GaN power devices are still in an early pha...