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Energy-feed power electronic loads can precisely control the phase and magnitude of the power supply output current, achieving the emulation of loads. Moreover, they can feed energy back to the grid for energy regeneration, demonstrating significant research value. This article proposes an energy-fed power electronic load topology and control method that can realize the static and dynamic simulation of linear and non-linear loads and take into account the simulation needs of single-phase, three-phase three-wire, and three-phase four-wire loads. The main circuit uses a two-stage back-to-back AC/DC/AC structure: the front side is a three-phase four-wire split capacitor PWM rectifier bridge, which is used to simulate loads under various operating conditions; the back side is a three-phase three-wire PWM inverter bridge, which realizes the energy feeding back to the grid and reduces the waste of energy; and the intermediate side uses a split capacitor to equalize the voltage and achieve voltage stabilization. The topology is analyzed under the simulation demands of three-phase balanced, three-phase unbalanced, single-phase and non-linear loads. Finally, a MATLAB(R2022a)/Simulink simulation platform is built for a power electronic load with a rated capacity of 200 kVA. The simulation results verify the effectiveness, feasibility, and advancement of the power electronic load proposed in this article. [ABSTRACT FROM AUTHOR]

In terms of high-current measurement of capacitors, PCB Rogowski coils have attracted much attention because of their small size and easy installation. However, they are vulnerable to electromagnetic interference. In order to improve the immunity of the coil, this paper studies the influence of the structure and parameter changes of the double-layer PCB coil on the measurement accuracy of mutual inductance. By testing the frequency response of four common coil structures, a differential winding coil structure is proposed. Based on the measurement of large capacitance current, the influence of non-electrical parameters of coils on the measurement accuracy of mutual inductance is experimentally verified. [ABSTRACT FROM AUTHOR]

Lifetime prediction of dc-link capacitors in a single drive has been discussed before, which indicates that the capacitor in a standard drive meets serious reliability challenges and in a slim drive does not. However, in most of the applications, drives are connected in parallel with the power grid. The large amount of harmonic distortion produced by nonlinearity drives may transmit and couple between grid and drives, which changes the stresses of devices as well as the dc-link filters. Therefore, the estimated results in a single drive cannot be extended to multiple drives any more. This article investigates the lifetime of dc-link capacitors in multiple drives system. First, by decoupling the interactions among grid-connected drives, a simplified equivalent circuit model and its analytical model to obtain the dc-link continuous current in multiple drives is proposed, which releases the designers from configuring the large simulation for multiple drives. Then, applying the lifetime prediction method, the lifetime of dc-link capacitors in multiple drives is investigated, in terms of types of drives, numbers of drives, and grid conditions. The results show that the lifetime of the standard drives extends in the multidrive systems and the lifetime of the slim drives decreases in the multidrive systems, which break the previous mind. Finally, based on the proposed analytical model and lifetime estimation method, the capacitor sizing from reliability aspect for multiple slim drives is given. The outcomes of the lifetime investigation could be a guideline for the design of the capacitive dc link in multidrive systems. [ABSTRACT FROM AUTHOR]

For the applications where a single capacitor is incapable to meet the needs, multiple capacitors are connected in series or in parallel as a bank to fulfill the capacitance and voltage rating requirements. Even though some commercial products have already existed in the market, most of the designs use the same capacitors or combine different types of capacitors by experience, so that the volume, cost, reliability, and power loss are not optimized. To the best knowledge, no quantitative design considering all these design aspects is available for capacitor banks. This article proposes a model-based optimal design method for hybrid capacitor banks consisting of both electrolytic capacitors and film capacitors. Performance factors, such as impedance characteristics, lifetime, power loss, cost, and volume, are modeled and considered in the optimization process. The selection of the capacitance ratio between the two types of capacitors and the number of capacitors connected in parallel are analyzed based on specific design constraints. A case study of the dc-link capacitor bank design for a 5.5-kW inverter is presented to demonstrate the modeling and optimal design process. [ABSTRACT FROM AUTHOR]

This letter proposes a simple yet practical power loss model of dc-link capacitors used in single-phase inverters. The low-frequency and high-frequency capacitor ripple current components make the existing power loss models either oversimplified by ignoring the high-frequency effects or overcomplicated with detailed analytical solutions. The proposed simplified model can achieve negligible errors with respect to the detailed model without the need of double fast Fourier transform. Different modulations and topologies are analyzed to show the applicability of the proposed method. A 2-kW single-phase inverter case study is presented to demonstrate the accuracy and ease of use of the proposed model. [ABSTRACT FROM AUTHOR]

Capacitive dc-links are widely used in voltage source converters for power balance, voltage ripple limitation, and short-term energy storage. A typical solution, which uses aluminum electrolytic capacitors for such applications, is assumed to be one of the weakest links in power electronic systems, therefore, also becoming one of the lifetime bottlenecks of power electronic systems. Various passive and active capacitive dc-link solutions have been proposed intending to improve the reliability of the dc-links qualitatively, making great effort to diverting the instantaneous pulsating power into extra reliable storage components. In this paper, a generic topology derivation method for single-phase power converters with active capacitive dc-link integrated has been proposed, which can derive all existing topologies, and identify a few new topologies. According to the synthesis results, the main achievements in research on capacitive dc-link solutions are reviewed and presented chronologically as well as thematically ordered. Furthermore, the reliability-oriented design procedure is applied to size the chip area of active switching devices and the passive components to fulfill a specific lifetime target and system specification, as well as compare the overall capacitive energy storage, energy buffer ratio, and the cost of different solutions. The cost comparisons are performed with a scalable lifetime target and power rating. It reveals that different conclusions can be drawn with different lifetime targets in terms of cost-effectiveness. [ABSTRACT FROM AUTHOR]

The output characteristics and the transfer efficiencies of inductive power transfer (IPT) systems are affected by (but not limited to) the variation of parameters such as, variable load, misalignment between the primary and secondary coils, and resonance frequency detuning. This paper first analyzes the resonant conditions of all voltage-fed compensation topologies in IPT systems to achieve the load-independent voltage transfer characteristic at load-independent zero phase angle frequency. With these conditions, the parameters sensitivity to the key performance factors of the S-SP, LCC-S, LCC-P, and double-sided LCC compensated IPT systems are systematically investigated when considering the losses in coils and compensation networks. Comparisons of the quantitative sensitivity analysis and experimental results for all IPT systems are made in terms of the voltage transfer ratio and efficiency. These analyses can provide guidance for the selection of superior compensation networks to minimize the additional converter effort and simplify the control algorithm of closed-loop IPT systems. [ABSTRACT FROM AUTHOR]