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L’expérience du « test climat » dans les métropoles québécoises
No full textInternational audienceAu Québec, les grands projets d’aménagement font l’objet de « tests-climat », en amont des processus de décisions. Comment certains mouvements d’opposition se saisissent-ils de cet outil scientifique afin de remettre en question les choix menant à leur réalisation
Multi-line input network for class EF inverter with enhanced design flexibility
No full textInternational audienceThis paper addresses a new input network for the class EF inverter, which utilizes multiple transmission lines instead of the commonly used quarter-wave line. Experimental demonstrations at 15 MHz with 40 W output power are conducted, showcasing that enhanced performance can be achieved with the proposed input network
Gigahertz, Low-Cost Current Shunt with Retrofitting Capability for Characterization of Fast-Switching GaN Devices
No full textInternational audienceA low-cost current shunt based on a flexible polyimide printed circuit board (PCB) design is presented. With low insertion inductance in the range of 300 pH and bandwidth in excess of 1 GHz, the design is suitable to be used for characterization of very fast GaN devices. Due to its very low thickness, it is possible to retroactively integrate the sensor into many existing designs that were not specifically prepared for current measurement. Thus, it offers an alternative to designing specific PCBs only for switching characterization
A Superconducting Half-Wave Rectifier: Principle and Experiment
No full textInternational audienceThe superconducting rectifier is a low-power consumption, high-current rectifying device with significant potential for application in AC-DC conversion systems. In this study, we have clarified its operating principle from a circuit perspective. It is demonstrated that the rectification function in a superconducting rectifier is attributed to its time-varying resistance, which is controlled by external sources. An AC field-controlled superconducting half-wave rectifier was developed. By constructing an experimental platform, we measured the rectified voltage and current of the rectifier under various operating conditions. The rectifier successfully converted an AC current into a 34 A DC current, powering a superconducting coil load
Ultra-Fast Bidirectional SiC Solid-State Circuit Breaker for 800V / 400A Aircraft Applications
No full textInternational audienceThe shift toward electric propulsion in aircraft brings unique challenges to power distribution and protection systems, requiring the advancement of technologies like solidstate circuit breakers (SSCBs). This paper explores the pivotal role of SSCBs in electric aircraft, highlighting their potential to improve safety, reliability, and efficiency in 800V high-power environments. However, their integration in aviation also presents challenges, such as ultra-fast fault isolation within complex electrical architectures, efficient thermal management, enhanced reliability and safety, and the demand for lightweight, compact designs. This paper addresses these challenges by analyzing current technological limitations, exploring potential solutions, and presenting experimental results from a bidirectional silicon carbide (SiC) SSCB that successfully detects a 1kA fault current with a response time of less than 1µs. The results emphasize the need for continued innovation in SSCB technology to meet the stringent demands of next-generation electric aircraft
Single Active Bridge DC/DC Converter as Auxiliary Power Supply for Medium-Voltage Multilevel Converters
No full textInternational audienceModular multilevel converters are used in various applications such as HVDC, STATCOM or PV. A robust auxiliary power supply is essential to ensure full control of each stage at all times, even during failure scenarios. Due to the high voltage between the cell and the external input power, high isolation is required. This paper presents a Single Active Bridge (SAB) auxiliary power supply for MMCs. The proposed design achieves high isolation and is capable of powering more than 100 MMC cells simultaneously. The high stray inductance resulting from the isolation distance can be included in the converter design. The system can handle asymmetric load changes of up to 24% on a single stage without causing overvoltage conditions. Furthermore, a novel solution is presented to address highly asymmetrical load scenarios
A Current Source Buck-Boost Inverter for Active and Reactive Power Injection to the Low Voltage Grid
No full textInternational audienceWith the ever-rising dependence and demand for Renewable Energy Sources, the development of reliable power converters that correspond to the modern-day grid requirements has become more necessary now than ever. In this paper a Bidirectional Buck-Boost inverter acting as a current source is proposed. This is realized by designing a Buck-Boost converter to operate only in the DCM mode, followed by an unfolding inverter to connect to the low voltage network. This arrangement offers complete freedom of choice both for the output current amplitude as well as its phase relative to the grid voltage. So, it is possible to precisely select the output power factor and inject both active and reactive power into the low voltage grid, by designing judiciously the converter control unit. Simulation and experimental results are used to validate the converters' design and operation
Design and Analysis of a Three-Phase Single-Stage AC-DC Converter with Series Resonant Tank for Electric Vehicle Charging Stations
No full textInternational audienceThis paper presents an analysis and design of a three-phase single-stage ac-dc converter with an LC resonant tank for use in the charging infrastructure for electric vehicles (EVs). The analyzed converter simplifies the power conversion process by reducing the number of components, enhancing both the system reliability and the efficiency. The operation of the converter is modeled and different modes of operation are presented. The introduced single-stage converter achieves zero voltage switching (ZVS), to minimize power losses and to optimize system performance. A prototype is designed and implemented, achieving 95.9% efficiency with low input current total harmonic distortion (THD) and output voltage ripple utilizing small non-electrolyte capacitors. The simulation and experimental results validate the design and control scheme, showing the effectiveness of the proposed approach for modern EV charging stations
Analysis of Leg-Open Fault of Three-Phase Delta-Delta LLC Resonant Converter
No full textInternational audienceHighly reliable LLC resonant converters operating even under fault conditions are important in aerospace, data center, and electrolyzer applications that require continuous and stable power supply. Therefore, analyzing the operating characteristics and researching methods for maintaining output voltage is essential. Thus, this paper analyzes the operation mode and resonant characteristics of a three-phase deltadelta LLC resonant converter after faults, focusing on open-circuit faults. Based on the analysis, equivalent circuits and voltage gain curves after the faults are derived and compared with those before the faults. The decreased output voltage due to the faults are recovered through PFM(Pulse Frequency Modulation). Consequently, the output voltage is recovered without additional components, and it is intuitively interpreted that the operating frequency is adjusted to achieve voltage gain as the resonant frequency changes after the faults. The analysis results are verified by PLECS simulation
Impact of Operating Load Limits on the Control Strategy and Performance of Alkaline Electrolyzer Arrays in Renewable Energy Systems
No full textInternational audienceThis study examines the impact of varying operating load limits on control strategies and performance of alkaline electrolyzer arrays in renewable energy-based hydrogen production. Lower load limits improve hydrogen production by 10.63%, especially during low wind availability, but cause slight imbalances in load distribution