Optimal Design of MHz LLC Converter for 48V Bus Converter Application Yinsong Cai, Student Member, IEEE, Mohamed H. Ahmed, Student Member, IEEE, Qiang Li, Member, IEEE, and Fred C. Lee, Life Fellow, IEEE

Optimal Design of MHz LLC Converter for 48V Bus Converter Application Yinsong Cai, Student Member, IEEE, Mohamed H. Ahmed, Student Member, IEEE, Qiang Li, Member, IEEE, and Fred C. Lee, Life Fellow, IEEE

 Abstract—Intermediate bus architecture employing 48V bus converters is widely used in power supply applications. With the rapid increase of demanded power by these loads, higher efficiency and power density are driving better performance power management solutions. In this paper, a Gallium Nitride (GaN) based design of a two-stage solution is proposed. The first stage is a multi-phase Buck for regulation. The second stage is an LLC converter with fixed switching frequency for isolation. The detailed design and optimization of the LLC converter are studied. To achieve high power density and high efficiency, the transformer design becomes critical at MHz frequency. The matrix transformer concept is applied and a merged winding structure is used for flux cancellation, which effectively reduces the AC winding losses. A novel primary termination and via structure is proposed, resulting in great loss reduction. In addition, to study the current sharing of parallel winding layers, a 1-Dimensional analytic model is proposed, and a symmetrical winding layer scheme is used to balance the current distribution. Finally, the prototype for the two-stage bus converter is developed, with the peak efficiency of 96% and power density of 615W/in3.

 VIEW FULL PAPER: https://www.osti.gov/servlets/purl/1799217

Twelve-Step Voltage Source Inverter: A Three-Phase Six-Levels Inverter Using Planar Transformers Haitham KANAKRI, Euzeli Cipriano DOS SANTOS JR., and Maher RIZKALLA

 

Twelve-Step Voltage Source Inverter: A Three-Phase Six-Levels Inverter Using Planar Transformers Haitham KANAKRI, Euzeli Cipriano DOS SANTOS JR., and Maher RIZKALLA 

 Abstract—Multi-level inverters (MLIs) are becoming increasingly popular in high-speed motor drive systems for modern electric aircraft applications. However, two significant limitations are associated with current MLIs technology: (1) the high switching losses due to the high carrier switching frequency and (2) the complex modulation schemes required to maximize the DC source utilization. Consequently, the development of new topologies to mitigate these limitations is imperative for the rapid advancement of future electric aircraft systems. This paper introduces a six-level twelve-step inverter (TSI) that utilizes twelve switches and three planar high-frequency transformers. Implementing the proposed configuration ensures maximum DC source utilization, with a peak phase voltage of 5Vdc / 3. The proposed solution presents less semiconductor losses than the conventional MLIs, surpassing conventional MLIs, associated with neutral point clamped (NPC), flying capacitor (FC), and cascaded H-bridge (CHB). Experimental results demonstrate the TSI’s operation under static and dynamic conditions and its capability to function in three different modes: three-step, six-step, and twelve-step operations. The paper also offers a comprehensive design of the proposed planar transformer, supported by theoretical analysis, finite element analysis (FEA), and experimental validation.

VIEW FULL TEXT WEB: Page 263-273

 https://file.cpss.org.cn/uploads/allimg/20240927/CPSS%20TPEA%20V9N3.pdf

Design and Analysis of a Three-Phase High-Frequency Transformer for Three-Phase Bidirectional Isolated DC-DC Converter Using Superposition Theorem-by Yasir S. Dira ,Ahmad Q. Ramli ,Nadia M. L. Tan,and Giampaolo Buticchi

 

Design and Analysis of a Three-Phase High-Frequency Transformer for Three-Phase Bidirectional Isolated DC-DC Converter Using Superposition Theorem-by Yasir S. Dira ,Ahmad Q. Ramli ,Nadia M. L. Tan,and Giampaolo Buticchi Institute of Power Engineering, Universiti Tenaga Nasional, Kajang 43000, Malaysia; yasirsabah291@gmail.com (Y.S.D.); qisti@uniten.edu.my (A.Q.R.) 2 Key Laboratory of More Electric Aircraft Technology of Zhejiang Province, University of Nottingham Ningbo China, Ningbo 315100, China 

 Abstract: Battery energy storage systems based on bidirectional isolated DC-DC converters (BIDCs) have been employed to level the output power of intermittent renewable energy generators and to supply power to electric vehicles. Moreover, BIDCs use high-frequency transformers (HFTs) to achieve voltage matching and galvanic isolation. Various studies have recently been conducted using soft magnetic materials, such as nanocrystalline, amorphous solids, and ferrite, to develop more compact and effective transformers with superior power densities. The HFTs in three-phase BIDCs are composed of three magnetic cores. However, this leads to low power density and high cost. Besides, the three-phase (3P) ferrite core has not been investigated for high-power converters such as 3P-BIDCs. This paper presents the design and development of a 3P-EE ferrite magnetic core for 3P-BIDCs. The area product design method was used to determine the core and winding design. The paper also proposes the use of the superposition theorem in conducting a magnetic circuit analysis to predict the flux density and magnetising inductance of the transformer core. Moreover, the use of the superposition theorem allowed the required air-gap length for balancing the distribution of flux density and magnetizing inductance in the transformer core to be determined. The balanced flux distribution and magnetizing inductance resulted in a uniform core loss and temperature in the transformer. This paper also presents the experimental results of the designed HFT operated in a 300-V, 3-kW 3P-BIDC. The experimental results showed that the proposed HFT achieved a balanced flux density and magnetizing inductance with a high power density and low cost. Moreover, the transformer performed at a maximum efficiency of 98.67%, with a decrease of 3.33 ◦C in the overall temperature of the transformer as compared to the transformer without air gaps.

VIEW FULL TEXT: https://www.mdpi.com/2071-1050/16/21/9227

Power Losses Analysis of Multiphase Interleaved DC-DC Boost Converter using OrCAD PSpiceSoftware-A.A.Bakar Department of Electrical Engineering Universiti Tun Hussein Onn Malaysia-T.Sithananthan Department of Electrical Engineering Universiti Tun Hussein Onn Malaysia

2024 IEEE 4th International Conference in Power Engineering Applications (ICPEA), 4-5 March 2024

 Power Losses Analysis of Multiphase Interleaved DC-DC Boost Converter using OrCADPSpiceSoftware 

A.A.Bakar Department of Electrical Engineering Universiti Tun Hussein Onn Malaysia Johor, Malaysia afarul@uthm.edu.my S.SaimanDepartment of Electrical Engineering Universiti Tun Hussein Onn Malaysia Johor, MalaysiaT.SithananthanDepartment of Electrical Engineering Universiti Tun Hussein Onn Malaysia Johor, Malaysia tharnisha97@gmail.com A.F.H.A.Gani Department of Electrical Engineering Universiti Tun Hussein Onn Malaysia Johor, Malaysia

 Abstract—DC-DC converters with multiphase structures are widely used in electrical and electronic devices because of their advantages over conventional boost converters, such as reduction in input current ripple and low conduction loss. As technology advances, more delicate needs have to be fulfilled for better load performance. Traditional boost converters are still feasible but with certain drawbacks, such as high current ripples, significant switching losses, and high switch voltage stresses. This paper presents a novel multiphase DC-DC boost converter, with an output power range between 50 Watts to 200 Watts. The number of phases for this multiphase boost converter is limited to 5-phase. This paper focuses on power losses in the converter, namely conduction losses in diodes and MOSFET, switching losses in MOSFETs, as well as losses in inductors and capacitors. The discussion includes an analysis of the relationships between multiphase boost converters in terms of the number of phases and power loss. Simulation results show that the 3-phase DC-DC boost converter contributed to the least losses (at P=200 Watts) with the efficiency of 94.09 %, in addition to the smaller number of components used; by comparison between 3-phase and 4-phase. The performance analysis was done using OrCAD PSpice software.

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 http://eprints.uthm.edu.my/11701/1/P16758_3083f91e69916bfb3a101edf40a9cd8e%208.pdf

The Analysis and Comparison of Leakage Inductance in Different Winding Arrangements for Planar Transformer Ziwei Ouyang, Ole C. Thomsen, Michael A. E. Andersen Department of Electrical Engineering, Technical University of Denmark

 

The Analysis and Comparison of Leakage Inductance in Different Winding Arrangements for Planar Transformer Ziwei Ouyang, Ole C. Thomsen, Michael A. E. Andersen Department of Electrical Engineering, Technical University of Denmark

 Abstract -- The coupling of the windings can be easily increased by using multiply stacked planar windings connection. Interleaving is a well-known technique used to reduce leakage inductance and minimize high-frequency winding losses. The paper aims to analyze leakage inductance based on magneto motive force (MMF) and energy distribution in planar transformer and correct the formula of leakage inductance proposed by previous publications. The investigation of different winding arrangements shows significant advantages of interleaving structure. In this work, a novel half turn structure is proposed to reduce leakage inductance further. Some important issues are presented to acquire desired leakage inductance. The design and modeling of 1 kW planar transformer is presented. In order to verify the analytical method for leakage inductance in this paper, finite element analysis (FEA) and measurement with impedance analyzer are presented. Good matching between calculation, FEA 2D simulation and measurement results is achieved.

VIEW FULL TEXT: https://backend.orbit.dtu.dk/ws/portalfiles/portal/4594800/Ouyang.pdf