The adoption of standardized modular converters is an emerging trend in space-qualified electrical power systems. This modular approach streamlines design and manufacturing processes, potentially reducing development lead times for new satellite platforms. Building on previous research that identified the four-switch buck-boost (FSBB) converter with double digital control loops as an effective solution for solar array and battery interfacing, this paper presents the small-signal analytical modeling of control loops within a modular multiconverter architecture operating in boost mode with resistive load. A model of a single- and two-module system is proposed and validated through both simulation and experimental measurements, providing a robust framework for assessing inter-module interactions and their impact on overall system stability.

The four-switch buck-boost converter is a widely used topology due to its bidirectional capability and wide operating voltage range in applications such as battery chargers, photovoltaic applications, or smart grids. This article proposes an improved modulation strategy that reduces the average inductor current, like other state-of-the-art strategies, while also minimizing the inductor's current ripple and the maximum current during the buck-boost operating mode. The objective is to minimize core power losses and reduce conduction power losses in the transistors, thereby improving overall efficiency. To demonstrate this, a state-of-the-art reference modulation strategy is first analyzed. Next, modifications are suggested to obtain the improved strategy, and both are analytically compared. Finally, both modulations are implemented and experimentally validated.

This work presents the modeling and characterization of novel LFP-LTO lithium-ion cells with thick electrodes specifically designed for low-power applications, such as cardiac pacemakers. The selected cells, manufactured in a 2032 coin format with a nominal voltage of 1.9 V and a capacity of 15 mAh, were modeled using equivalent circuit models (ECMs), including both a basic first-order RC (1RC) and an enhanced three-RC-branch (3RC) Thevenin model. A multiobjective optimization strategy was employed to balance accuracy and computational complexity. To capture the dynamic behavior of the cells, a pulse-PRBS (Pulse-Pseudo-Random Binary Sequence) identification signal was applied, enabling precise parameter extraction over a broad frequency spectrum. Experimental results demonstrate that the 3RC model achieves voltage errors below 0.1%, making it suitable for accurate modeling under dynamic load conditions. Furthermore, the series configuration of two LFP-LTO cells reaches a nominal voltage of 3.7 V, matching the requirements of conventional pacemaker batteries. In addition, aging analysis was conducted by applying the same PRBS signal to the cells both before and after accelerated cycling and then modeling the results. These findings confirm that the 3RC model can also serve as a predictive tool for estimating battery aging and health. The proposed modeling methodology offers a reliable and efficient framework for integrating new thick-electrode technologies into biomedical applications.

Dual Active Bridge (DAB) converters have emerged as a leading solution for industrial applications that require high efficiency and bidirectional power transfer with isolation. The Triple-Phase-Shift (TPS) modulation scheme enables flexibility to enhance efficiency by choosing the operating point that minimizes power losses. This paper presents a novel, simplified methodology for reducing conduction losses in DAB converters using polynomial-based techniques. The operation of the DAB converter under TPS modulation is analyzed, and the corresponding modeling equations are derived. The proposed optimization method is described and validated through simulations in various design scenarios. The results demonstrate the existence of a set of three polynomials that effectively minimize the rms current based on the load conditions and the voltage ratio. Preliminary findings show that these polynomials will remain nearly constant across different converter designs, provided the output-to-input voltage ratio is the same.

This article presents a set of bidirectional dc-dc power converter solutions for high-voltage, high-power applications using magnetic and semiconductor devices that need to handle a small fraction of the rated power and voltage. The elements are integrated in an interleaved operation, which results in the generation of a low rms and pseudosine phase current. All these features result in a topology with a high level of efficiency, maintaining soft-switching over the entire operating range. Steady-state equations and simulation results are presented and then experimentally validated with a 25 kW prototype converter. Finally, it is verified that the solution is suitable for the needs of the proposed dc-microgrid scenario, that includes hydrogen production and an EV-charger, using solar PV-panels and battery energy storage systems as energy sources.

This paper discusses the implementation of a wireless inductive power transfer system for pacemaker applications. One of the inherent challenges in these systems is regulating the output voltage, as there is no direct physical connection from the primary. Additionally, there are other challenges, such as variability in magnetic coupling. First, resonant converters for inductive charging topologies are investigated for biomedical applications. Then, a control method based on the system’s modeling is proposed, eliminating the need for communication. This method is designed for systems with variable and unknown coupling and specifically for a resonant series–parallel topology. For an operation point, determined by the coupling factor, the primary current is measured to regulate the output voltage by adjusting the input voltage. The relationship between the input current and the input voltage is set by a look-up table. The effectiveness of this control strategy is validated in the PSIM simulator and with experimental results for a coupling range between 0.3 and 0.5, achieving a regulated output current error of less than 1%, and an output voltage range within the limits of the battery charger.

Electrospray thrusters are promising high-efficiency propulsion systems for small satellite platforms. While the available satellite power bus operates between 5V and 28V, these thrusters operate at kilovolt level, requiring DC/DC power conversion. These power converters must meet specific requirements, including bipolar output, compact design, and a reduced component count to fit within small platforms. In addition, they may incorporate current-balancing mechanisms to ensure thruster current symmetry, preventing spacecraft charging without a cathode. Electrospray thrusters are promising high-efficiency propulsion systems for small satellite platforms. While the available satellite power bus operates between 5V and 28V, these thrusters operate at kilovolt level, requiring DC/DC power conversion. These power converters must meet specific requirements, including bipolar output, compact design, and a reduced component count to fit within small platforms. In addition, they may incorporate current-balancing mechanisms to ensure thruster current symmetry, preventing spacecraft charging without a cathode. This paper provides an overview of DC/DC power converters designed for electrospray thrusters, analyzing key trends and characteristics. Among various voltage-boosting techniques, converters based on isolated transformers and Cockcroft–Walton voltage multipliers emerge as the preferred solution. The four predominant architectures found in the literature, aside from commercial solutions, include resonant full bridge, Royer oscillator, interleaved boost, and flyback topologies. This survey offers a comprehensive comparison of the literature designs for electrospray propulsion, outlining the working principles of the topologies and their characteristics, suitability, and trends.

Failure analysis is a fundamental part of system safety and reliability, and allows early design decision-making in order to extend the life of systems and avoid accidents. Currently, there are multiple standard methodologies for performing failure analysis, being FMECA (Failure Modes, Effects and Criticality Analysis) one of the best known and most applied in multiple sectors. However, the FMECA methodology is an extraordinarily complex and time-consuming task, especially in the case of electronic systems that contain a high number of components. Nowadays, for generating feasible FMECA analyses it is necessary to assume simplifications, hypotheses and subjective criteria that limit the scope of the analysis and drastically affect the quality and credibility of the results. Simulation and automation tools are an ideal and necessary complement to provide FMECA analyses with greater accuracy and less subjectivity in the results obtained, as well as greater efficiency in the time spent on the analysis.

Electrospray thrusters offer remarkable efficiency at low power levels and compact form factor, positioning them as promising propulsion systems for small satellite platforms. The ability of electrospray thrusters to emit both positive and negative ion beams has significant implications for charge neutralization. In theory, electrosprays could function without the need for an external cathode. If two separate thrusters are operated simultaneously with one emitting a positive ion beam and the other an identical negative ion beam, the spacecraft would theoretically remain charge-neutral, allowing the thrusters to operate continuously without inducing spacecraft charging. This article explores the self-balancing of emitted currents, and consequently the ion beams, by incorporating a capacitor as a control element. This approach achieves current balancing without altering the operation of the power converter. The thruster’s behavior as an electrical load is simulated using a novel electrical model derived from experimental thruster data. This model, integrated within the converter, demonstrates that the inclusion of a capacitor effectively balances the emitted currents. Experimental validation aligns with the simulation results, confirming current balance with a relative error between polarities of only 1

Recent advancements in electric propulsion have revolutionized related industries. Electrospray thrusters offer an alternative to traditional systems, potentially enabling wide adoption in small satellites due to electronics miniaturization. Electrospray thruster thrust correlates directly with emitted current. Maintaining a constant current by adjusting voltage ensures consistent thrust, underscoring the importance of monitoring thruster behavior. Furthermore, the sensor architecture can be configured to measure either the positive or negative rail with only changes to the wiring, requiring no additional modifications. This paper introduces a high-side sensor for kilovolt, microamp, and temperature measurements with a digital interface. Designed with automotive-grade components, it underwent a 7-hour validation test with electrospray thrusters.

Electrospray thrusters offer remarkable efficiency at low power levels and compact form factor, positioning them as promising propulsion systems for small satellite platforms. This paper introduces the design of a miniaturized Power and Control Unit for electrospray thrusters. The system fits within the pocketsat form factor while ensuring high-performance, high-voltage power conversion and effective thrust generation in this propulsion technology. The paper goes through the architecture of the Power and Control Unit and its different subsystems, where the high-performance power converter is studied in detail. The system is built in a 42 $$\times$$ × 42 $$\times$$ × 25 mm3 and 39 g weight stacked hardware unit, achieving a configurable bipolar voltage output with the implemented control algorithm. The system undergoes experimental verification, where a power conversion efficiency over 90% was measured within the output range of 2-10W and 1-2kV, validating soft-start, thruster voltage alternation, and variation of the thruster set point in real time. The final milestone is the successful 7-hour emission test with electrospray thrusters under vacuum conditions, ensuring the system’s suitability for real-world applications related to electrospray propulsion for small satellites.

The need for battery storage in applications using solar energy requires, in most cases, the use of topologies with bidirectionality and high-power density. The Dual Active Bridge converter meets all requirements in most applications and is a widely used topology.In this paper, a Dual Active Bridge converter for elevator applications has been analyzed and optimized. Firstly, a general overview of the converter is presented, and its different modulation strategies are discussed. Simulation tools have been used to optimize the system to find the optimum value of inductance to minimize transistor power losses. The converter has been implemented and tested under different values of inductances. Finally, the transistors bridge temperature has been compared depending on the implemented inductance, and an improvement in the system has been verified.

In recent years the implementation of wireless power systems has increased due to improvements in technology and efficiency. Some advantages of wireless power transfer technology are reliability, safety, and convenience of use. One of the challenges with these systems is output regulation, as there are no physical wires to access it. Further complications are the variability of coil coupling and output power in the case of chargers. Firstly, this paper has summarized some of the main techniques for controlling the output of inductive power technology. Moreover, a predictive free communication control from the primary is proposed. It is aimed at charging systems with constant but unknown coupling, using a small drone charger as a reference. This control allows the secondary side to be simplified and acts faster than a control loop at the output due to the predictive measurement and feedforward operation. The simulation results for an output voltage of 5 V show an error of less than 3 % for a coupling range of 0.25 to 0.5.

The Four-Switch Buck-Boost converter (FSBB) or Non-Inverting Buck-Boost (NIBB) is a widely used converter due to its bidirectionality and the capability to work with a wide range of input and output voltages. This converter can be used for battery charges, photovoltaic applications, and smart grids. Several papers present different strategies to reduce the average current through the inductor to improve the converter's efficiency.This paper aims to reduce the current ripple through the inductor to minimize the power losses in the core. Firstly, the current modulator presented in the state of the art will be analyzed. Then some modifications will be suggested, and the modulators will be analytically compared. Finally, both modulations will be implemented and tested.

This article presents two equivalent electrical models of electrospray thrusters verified with experimental data. The first model presented in this article aims to improve the electrospray thruster representation in HV-dc/dc converter's steady-state and closed feedback-loop response simulations since it is one of the most critical subsystems of an electrospray propulsion system. The proposed model, adapted from cold cathode fluorescents lamps (CCFLs) models, is composed of basic electrical elements (resistors, capacitors, and diodes), and it is implemented in SIMULINK/MATLAB. The model parameters are extracted from experimental data, and it is possible to export them to any electrical simulation tool. The second model incorporates temperature dependencies based on electrospray physics to predict the thruster's behavior within an experimental data set. The absolute error between the experimental and simulated data is less than two microamps for the nontemperature-dependent model and two and five-tenths microamps for the temperature-dependent model in the thruster's operating range. Besides, the relative error is less than 4% for the nontemperature-dependent model and less than 8% in the thruster's operating range for the temperature-dependent model. A comparison with previous models is quantified showing that the models presented in this article are a better approximation, validating the proposed models.

The non-idealities of the components used in power converters can lead to suboptimal operating solutions if they have not been considered in the preliminary analysis. In particular, the idealization of the coupling in the integrated magnetic components may represent one of the major sources of differences in the final behavior concerning the expected one, with implications for the performance. In this paper, the effects of considering a non-ideal coupling in the Bidirectional Buck-Boost converter with Magnetic Coupling are explored, and an optimized use of the Triple Phase Shifted modulation considering them is proposed to reduce the switching and conduction losses. The validation of the theory is performed through experimental measurements on a prototype in representative scenarios of the boost operation.

Integrated magnetic components (IMCs) are used to save volume and increase the efficiency of many dc power converter topologies. However, their design is not a straightforward procedure, and it is possible to find different modeling strategies in the literature. Using one or another modeling approximation significantly impacts the analytical results' accuracy and may lead to erroneous solutions and to the need for a time-consuming redesigning process. In this study, an IMC with an EE-type structure and three air gaps, named E3E, is described and modeled under different modeling alternatives with an increasing degree of complexity. Additionally, a new expression to analytically model the window reluctance, key for coupling coefficient estimation, is proposed inspired by the E3E structure finite element analysis. The error of using each E3E modeling alternative is studied, by comparing the analytical results with the measurements obtained for several assemblies, including one for a dc-dc converter application case.

Some of the advantages of wireless power transfer technology are reliability, safety and convenience of use, features suitable for biomedical applications. In recent years the implementation of these systems has increased due to improvements in technology and efficiency. This paper reviews the state of the art in wireless power transfer for cardiac pacemaker charging using inductive power technology with resonant converters. Resonance frequency, magnetic coupling or typical topologies are the most studied concepts by researchers in wireless charging systems for pacemakers. The compilation of authors and knowledge in this field provides an overview of the current status and allows further progress to be made in making this technology viable.

The Four Switch Buck-Boost converter (FSBB) is a widely used topology for DC-DC applications in which isolation is not required. This is mainly due to its bidirectionality, and the ability to operate under a wide range of input and output voltages. There are several modulation strategies for this converter, each one with its strengths and weaknesses.In this paper, several modulators from state of the art are compared, and the losses of the transistors and the inductor are computed. With this information, it is intended to select the best modulator depending on the input and output voltages, output power, and hardware limitations of the designed FSBB.

The Dual-Active-Half-Bridge (DAHB) converter is being explored as a candidate for applications requiring low cost, reliable and power dense power conversion. This paper describes the discrete modelling of a DAHB converter, applicable to different modulation strategies such as Single Phase Shift (SPS), Dual-phase-shift (DPS) or Triple-Phase Shift (TPS). Discrete modelling allows a very accurate description of high frequency effects, phenomena that cannot be effectively predicted with averaged methods. This is especially useful if the half-bridge capacitance is small and the resonant frequency is comparable to the switching frequency. The modelling approach generates an accurate dynamic model, as well as a steady-state model predicting very precisely the current and voltage wave-forms, which in turn allows to make an optimal design based on numerical methods. The model has been validated with time domain simulations in both dynamic and static operation.