The double-sided LCC (DLCC) compensation has been widely used in inductive power transfer (IPT) systems because it has a load-independent current source output directly proportional to the coils’ coupling, which makes it inherently safe against misalignment. The input current of the DLCC typically has high harmonic distortion due to the low-pass filter characteristic of the input LC components. Consequently, predicting the inverter’s turn-off current through circuit modeling using the first-harmonic approximation (FHA) would result in a significant estimation error. However, an accurate computation is essential to determine whether the inverter’s zero-voltage switching (ZVS) turn-on is achieved. This paper defines an analytical model that effectively predicts the inverter turn-off current point for any operating condition, i.e., when the diode rectifier operates in continuous and discontinuous conduction modes. It has been found that the inverter turn-off current depends on the loading condition. Therefore, the proposed method is based on modeling the equivalent load as the rectifier together with the battery. Experimental verification has been conducted using two IPT systems with nominal power levels of 3.7 kW and 7.7 kW.

The usage of an Auxiliary Resonant Commutated Pole (ARCP) circuit with an 11-level Cascaded H-Bridge (CHB) converter as an option for feeding high-power Wireless Power Transfer (WPT) track-pads in traction applications is proposed in this research. By utilizing a mathematical model to obtain the switching pulses of the ARCP circuit, a reduction in the conduction losses of the involved inductance can be achieved. Moreover, an optimization routine is developed to reduce the MOSFETs' root mean square current by finding each module's phase shift angles. The study uses the SAE J2954 standard to restrict the Electromagnetic Interference (EMI) in the frequency band between$400\ kHz$and$30\ MHz$. The success of the suggested technique is displayed by simulation results showing that it is possible to operate the CHB with Zero Voltage Switching in all modules of the power converter. Inductive Power Transfer applications applied in railways can benefit from this contribution due to the use of multilevel converters.

This paper presents the study of a 100kW electric vehicle (EV) fast charger based on a 12-pulse rectifier cascaded with two buck-type DC-DC converters. The proposed circuit operates with a triangular current shaping method which considerably improves the current harmonics performance of the system. The studied circuit is particularly suited for high power battery charging, being relatively simple to operate, requiring a low active semiconductor count (only two active switches), and because it employs circuit technologies well-established in the high power market. Above all, this EV fast charger meets the requirements of isolation, high efficiency, high output voltage and good power quality (low THD and unity power factor). This paper describes in detail the analytical modeling of the studied circuit, including the current harmonic input filter design which meets the grid standard requirement, and the loss modeling of the semiconductors and passive elements. The modeling and simulation results of the proposed 100 kW system are presented and analyzed.

The range anxiety and relatively long charging time issues of electric vehicles (EVs) have boosted the development of fast charging technology. With charging light EVs being the main focus in the past decade, a trend of promoting the charging infrastructures dedicated to heavy-duty EVs (HDEVs) such as E-trucks, and Ebuses has emerged to further the electrification of global transportation. Accordingly, the market is calling for advantageous standards, architectures, and power electronic circuits specialized in the fast charging of HDEVs. For the charging of HDEVs, the power rating of chargers can reach an ultra-high-power level (>1 MW) to ensure a charging time comparable to the refueling time of internal combustion engine (ICE) vehicles. At this power rating, the classic full power processing (FPP) two-stage AC-DC plus DC-DC architecture has limited space for improvement in terms of the efficiency and effective cost of the charger circuits. This thesis proposes a solution to the HDEV fast charger topologies. Firstly, the state-of-the-art EV fast charging technology, concepts of the hybrid rectifier, and partial power processing (PPP), which could be beneficial in advancing the charging architecture are reviewed. Based on the results of the literature review, a new unidirectional Input-Parallel-Output-Series (IPOS) three-phase hybrid rectifer topology is proposed and analyzed. This topology is derived from the Input-Parallel-Output-Parallel (IPOP) hybrid rectifier in [1] by connecting the DC-links in series instead of in parallel. The IPOS topology is beneficial at ultrahigh power rating to interface heavy-duty EV batteries which require a high and wide output voltage range, enabling the system to deliver an output voltage range of 800∼1500 V to interface the next-generation of EV batteries with available 600/1200V commercial semiconductors. Besides, the proposed topology is efficient, cost-effective, and scalable with the grid input current harmonic components in compliance with the IEEE-519 standard. The benefits of the IPOS topology are supported by circuit derivation, control strategy, analytical modelling, simulation, and experimental verification of the current modulation technique. Index terms— fast charging, hybrid rectifier, partial power processing, power factor correction, AC–DC converter

In inductive power transfer applications, it is possible to ensure high efficiency of the main coils by operating at the optimum load. Since the optimum load depends on the coupling between the main coils, the operation needs to be adapted to match this case at different alignment conditions. This paper proposes a method to keep the optimum load constant by varying the natural resonant frequency of both the primary and secondary circuits of a S-S compensation network. This is possible by changing the value of the compensation capacitors at different alignments. This strategy differs from the ones found in the literature, where the input and the output voltage are changed to always match the optimum load. The proposed concept is proven through circuit simulations of an 11 kW EV battery charging system, and several strategies for the implementation of the variable capacitance are discussed.

Industrial wireless charging systems use standardized coils to guarantee interoperability between different manufacturers. In combination with these coils, the compensation network can still be designed and optimized. This paper explains the step-by-step design of the compensation network for a 7.7 kW wireless charging system (power class WPT2), which is composed of standardized coils. The compensation network must satisfy the output power and voltage requirements, the soft-switching of the inverter, and the limit of voltage and current stress on the components. The S-S compensation network is found to be unfeasible for those coils, and an optimized double-sided LCC compensation network is designed. The 3-phase grid connection is selected despite the 1-phase one because it gives the lowest total conduction losses. Finally, two parallel SiC MOSFETs C3M0075120K are chosen as inverter's switch because of their low conduction losses. This solution can achieve a payback time within a year with respect to the cheapest one.

This paper aims to investigate the radiated magnetic field by 11 kW inductive power transfer (IPT) systems used for the charging of electric vehicles. Two reference designs suggested by SAE J2954 are studied. Both designs are analysed to obtain the coils winding currents, and 3D FEM models are built in COMSOL without considering the car chassis, which constitutes a conservative approach. The magnetic field intensity at specific distances from the IPT coupler are calculated. Finally, the simulation results are compared with the respective magnetic field limits defined in the international standards SAE J2954, IEC 61980-1 and ICNIRP. The results show that the magnetic field radiations at 10 meters points are significantly lower than the limits established in the SAE J2954, while the emissions at 0.9 meters points are only slightly below the limits defined by ICNIRP.

This paper aims to identify the difference between foreign object (FO) and misalignment in terms of their influence on inductive power transfer (IPT) systems. This is performed through magnetic and equivalent circuit analysis of the mutual inductance, primary input impedance, charging pad terminal impedance and current harmonics. Experiment measurements on an IPT prototype are carried out to verify the analysis. It is found that: the charging pad terminal impedance under FO condition has a more pronounced decrement than that of misalignment; the mutual inductance under FO condition shows negative correlation with frequency, while positive for misalignment; the absolute value of the input impedance is decreased by FO and increased by misalignment; the influence of FO and misalignment on the THD of the input current is minimal. Finally, it is possible to detect FO and distinguish it from misalignment, through the variation of the primary pad terminal inductance, as well as the frequency dependence of the primary input impedance and the mutual inductance.

This work presents a unidirectional three-phase PFC rectifier well-suited for application targeting high efficiency and/or high power density, such as DC-type electric vehicle chargers. Herein, a quasi-single stage AC-DC converter is proposed where a conventional three-phase DELTA-switch voltage source rectifier is cascaded to a PWM interleaved buck-type DC-DC converter by means of a low energy storage DC-link. The characteristics of the presented power electronics, including the principles of operation, modulation strategy, suitable PWM control scheme, and dimensioning equations are described in this paper. The presented circuit is benchmarked against other solutions for a 50 kW power capability battery charger. The results show a superior power efficiency of the proposed system.

In power electronic applications the replacement of the state-of-art Si-based IGBTs by SiC-based Mosfets can bring improvements to the performance metrics of several systems, such as higher efficiency and increased power density. Currently, the cost of SiC semiconductor technology is far greater than that of Si-based devices. Therefore, the utilization of the intrinsic body-diode of the Mosfet chips as replacement of any additional anti-parallel SiC Schottky diode chips makes economic sense. Unfortunately, little information about the body-diode ruggedness is available in the datasheets or in the literature, which leads to concern about the device long term reliability. This article verifies the robustness of the body-diodes of three commercial SiC Mosfets in 10 μs short surge current operation with additional 80% rated reverse blocking voltage after surge. The results show that the tested semiconductors can impressively withstand several times their rated current without showing signs of degradation.

Back-To-Back (B2B) Voltage Source Converter (VSC) with AC-side LCL filters can be adopted for parallel AC-DC distribution links. In this paper, Grid-side Current Control (GCC) for the inner/fast control loops of the front- and backend power electronics are implemented in order to enhance the system performance against grid disturbances. Herein, a notch filter-based GCC scheme with a harmonic rejection control is proposed which is able to deliver attenuation to the LCL filter resonances while suppressing the harmonics in the grid-side currents originated when the AC voltages are distorted. The results obtained in MATLAB/SIMULINK and an experimental prototype show that the studied GCC method can successfully mitigate the influence of grid voltage harmonics, while providing a stable power control for the hybrid AC-DC distribution links.

This article proposes a power converter solution for 1.5 kV DC photovoltaic applications and benchmark the benefits of commercially available SiC MOSFETS for the system power efficiency. The circuit solution is based on a full power factor three-level active neutral-point-clamped converter featuring reduced numbers of high-frequency switched semiconductors. A combination of Si IGBT and SiC MOSFET is selected for the converter implementation because of the tradeoff between system cost and power efficiency. Finally, the advantages of the proposed converter is verified by the analysis of a 200 kVA power generation system employing this solution and other conventional two- and three-level voltage source converters.

This paper discusses new three-phase ac-ac Indirect Matrix Converter (IMC) topologies featuring higher power efficiency than conventional IMCs. Initially, a new Inverting-link Matrix Converter (ILMC) with lower conduction power losses than a standard ILMC for voltage step-down operation is proposed. New Ultra-Sparse Matrix Converters (USMCs) well-suited for voltage step-down applications are also presented. These circuits have redundant current paths to distribute the impressed dc-link current to the input terminals which can be potentially used to reduce semiconductor losses. A voltage step-up USMC, referred to as delta-switch USMC (Δ-USMC), well-suited for wind power generation systems, where low inductance machines are used, is also analyzed. In order to benefit from the best features of the proposed IMCs, standard and new space vector modulations featuring distinctive commutation schemes are presented. Finally, to demonstrate the advantages of the studied IMCs, power loss comparisons of these solutions and standard IMCs rated to 10 kW are shown.

This paper presents highly efficient three-phase unidirectional buck-type unity power factor rectifiers well-suited for various power electronic applications such as high power EV battery charging or DC distribution systems. The circuits are assembled by incorporating two auxiliary circuit branches into standard three-phase buck-type PFC topologies, each one comprising of one active switch and three diodes. This enables redundant current paths for distributing the impressed output DC currents to the AC input terminals, which can be potentially used to reduce the system's total semiconductor losses and/or increase its output power capability. The advantages of a new converter constructed with a three-phase six-switch buck-type PFC, including the principles of operation, modulation strategy and suitable control structure are described in this paper. Finally, the proposed converter is compared with the conventional six-switch buck-type converter and SWISS rectifier. According to the results, the studied AC-to-DC system is the topology of choice for a buck-type PFC.

This paper discusses three-phase bidirectional high-power factor mains interfaces for application in smart-houses featuring a local DC distribution grid. The DC grid demanded power can be supplied by local DC generators, such as renewable power sources, and/or by the public three-phase AC mains, which gives the option of feeding back power into the mains in case of a low local power consumption. In order to generate a local 400V DC bus, bidirectionally connected to the European three-phase low voltage AC mains rated at 400V line-to-line, buck-type converter topologies are required. Several possible converter concepts are initially presented and further comparatively evaluated based on the following performance indices: total required semiconductor chip area, overall efficiency, overall passive components volume, and required EMI filter damping. As result of the comprehensive evaluation, the Bidirectional 3rdHarmonic Injection Active Filter Type Rectifier with DC/DC Output Stage is identified as most advantageous topology for the realization of a bidirectional buck-type PFC rectifier in the considered power range of 5 to 10 kW.