Search Results (273)

Wireless power transfer (WPT) technology offers a convenient, efficient, and environmentally robust power supply solution for rack-and-pinion modules. For WPT systems in such modules where the transmitter coil is a long rail, increasing the transmitter coil turns to enhance mutual inductance leads to issues like high cost, low efficiency, and installation difficulties. This paper introduces a relay resonator to strengthen system coupling and proposes a three-coil design scheme employing a single-turn long rail as the transmitter coil. The proposed all-detuned LCC-S-S topology exhibits constant output voltage (CV) and zero phase angle (ZPA) input characteristics while accounting for all cross-mutual inductances and coil resistances. The frequency detuning level of the relay resonator critically governs the system’s power transfer efficiency and directly determines the operational mode of the rectifier—either continuous conduction mode (CCM) or discontinuous conduction mode (DCM). To maximize system efficiency, the optimal detuning frequency of the relay coil is selected under CCM operation. Through optimized design of the three-coil parameters, the final prototype achieves an output power of 106.743 W and an efficiency of 90.865% when integrated with a 1200 mm single-turn long-rail transmitter coil. Full article

The Polish Free-Electron Laser (PolFEL), which is currently under construction in the National Centre for Nuclear Research in Świerk near Warsaw, will comprise an electron gun and from four to six cryomodules, each accommodating two nine-cell TESLA RF superconducting resonant cavities. To cool the superconducting resonant cavities, the cryomodules will be supplied with superfluid helium at a temperature of 2 K. Other requirements regarding the cooling power of PolFEL result from the need to cool the power couplers for the accelerating cryomodules (5 K) and thermal shields, which limit the heat inleaks due to radiation (40–80 K). The machine will utilize several thermodynamic states of helium, including two-phase superfluid helium, supercritical helium, and low-pressure helium vapours. Supercritical helium will be supplied from a cryoplant by a cryogenic distribution system (CDS)—transfer line and valve boxes—where it will be thermodynamically transformed into a superfluid state. This article presents the architecture of the CDS, discusses several design solutions that could have been decided on with the use of second law analysis, and presents the design methodology of the chosen CDS elements. Full article

Vehicle-to-home (V2H) technology enables electric vehicles (EVs) to supply power to residential loads, offering enhanced energy self-sufficiency and backup capabilities. Accurate voltage regulation is essential in such systems, especially under nonlinear and time-varying load conditions. The control method for three-phase four-wire (3P4W) converters plays a vital role in addressing these challenges. In the control configuration of such systems, the non-ideal proportional-resonant (PR) controller stands out due to its ability to reject periodic disturbances. However, the comprehensive study on the discretization of this controller for digital implementation in 3P4W systems has not been available in the literature to date. This paper presents a comparative study of several discretization methods for non-ideal PR controllers. The continuous-time complete transfer function of the integral term of non-ideal PR controllers is discretized using techniques such as Forward Euler, Backward Euler, Tustin, Zero-Order Hold, and Impulse Invariance. Additionally, the discretization methods based on two discrete integrators for the non-ideal PR controller, such as Forward Euler and Backward Euler, Backward Euler and Backward Euler plus computational delay, and Tustin and Tustin, are also evaluated. In the MATLAB/Simulink platform, through evaluating the performance of the non-ideal PR controllers, which are discretized using the above discretization methods, in controlling the output voltage of the 3P4W converter in the V2H application under nonlinear load scenarios, including substantial and sudden changes in load, the discretization method Backward Euler and Backward Euler plus delay is recommended. Full article

In order to achieve a long-pulse-width output, a new long-pulse-width modulator based on the charging power supply of LCC-type high-frequency resonant converters and the pulse-generating unit in series IGBT switching technology has been designed. The relationship between the resonant cavity gain and the switching frequency has been derived. In the charging phase, the critical intermittent control mode is used to increase the charging speed, and in the voltage stabilization phase, the hysteresis burst control strategy is used to improve voltage accuracy. The simulation results show that the output pulse amplitude is 10 kV, the pulse width can reach 650 μs, and the top-drop is about 12%. Thus, a long pulse width modulator is developed. The output pulse voltage can reach 4 kV, and the output pulse width is 650 μs. The power supply reduces the capacity of the energy storage capacitor, which has industrial application value. Full article

A closed-loop transmission line (TL) coupled to an LCR resonator is used in this study for a fully-integrated CMOS rotary traveling wave oscillator (RTWO) based on the rotary traveling wave principle. A technique for the suppression of magnetic coupling noise is presented with eight-shaped inductors. The design and measurement of an 8.53 GHz oscillator in the TSMC 0.18 μm CMOS technology are discussed. The fully-integrated chip occupies a die area of 1.2 × 1.2 mm². The oscillator consists of four sub-oscillators and uses four 1:1 symmetric twisted transformers, with the secondary inductors connected to form a twisted closed-loop transmission line for coupling the sub-oscillators. The transformers are configured as eight-shaped structures to minimize the far-field magnetic field radiation from each transformer and the whole transformer. At a supply voltage of 1.7 V, the power consumption is 5.84 mW. The free-running oscillation frequency of the RTWO is tunable from 8.53 GHz to 10.0 GHz. The measured phase noise at a 1 MHz frequency offset is −122.4 dBc/Hz at an oscillation frequency of 8.53 GHz, and the figure of merit (FOM) of the proposed VCO with a specific inductor layout is −193.4 dBc/Hz, surpassing other similar RTWOs. The FOM with a tuning range (FOM_T) is −195.96 dBc/Hz. Full article

This paper presents a wide-tuning-range, low-power tunable active inductor (AI) designed and fabricated using 130 nm CMOS technology with six metal layers. To achieve high performance with a relatively small silicon area and low power consumption, the AI structure is carefully designed and optimized using a cascode stage, a feedback resistor, and multi-gate finger transistors. In the proposed circuit topology, inductance tuning is realized by adjusting both the bias current and the feedback resistor. The performance of the circuit is evaluated in terms of tuning range, quality factor, power consumption, and chip area. The functionality of the fabricated device is experimentally validated, and the fundamental characteristics of the active inductor are measured over a wide frequency range using a Cascade GSG probe, with results compared to simulations. Experimental measurements show that, under a 1 V supply, the AI achieves a self-resonant frequency (SRF) of 3.961 GHz and a quality factor (Q) exceeding 1586 at 2.383 GHz. The inductance is tunable between 6.7 nH and 84.4 nH, with a total power consumption of approximately 2 mW. The total active area, including pads, is 345 × 400 µm². Full article

This paper presents an enhanced bipolar control strategy for 400 Hz three-phase inverters in aviation ground power supplies, with a focus on maintaining symmetry in power output under unbalanced load conditions. The strategy integrates Linear Active Disturbance Rejection Control (LADRC) for robust positive sequence voltage regulation, Proportional Integral with repetitive control (PI + RC) for harmonic suppression in positive sequence currents, and a Quasi-Proportional Resonance (QPR) controller for negative sequence components in the static coordinate system. By doing so, it simplifies negative sequence control and combines PI + RC to improve the dynamic response and eliminate periodic errors. In the context of symmetry, the proposed strategy effectively reduces the total harmonic distortion (THD) and the three-phase current imbalance degree. Simulation results show significant improvements: under balanced loads, THD is reduced by 41.5% (from 1.95% to 1.14%) compared to traditional PI control; under single-phase and three-phase unbalanced loads, THD decreases by 52.7% (2.56% to 1.21%) and 48.1% (2.39% to 1.24%), respectively. The system’s settling time during load transients is shortened by over 30%, and the three-phase current imbalance degree is reduced by 60–70%, which validates the strategy’s effectiveness in enhancing power quality and system stability, thus restoring and maintaining the symmetry of the power output. Full article

This paper presents an active phase shifter for phased array system applications, implemented using 0.18 μm SiGe BiCMOS technology. The phase shifter circuit consists of a wideband quadrature signal generator, a vector modulator, an input balun, and an output balun. To enhance the bandwidth, a polyphase filter is employed as the quadrature signal generator, and a two-stage RC-CR filter with a highly symmetrical miniaturized layout is cascaded to create multiple resonant points, thus extending the phase shifter’s bandwidth to cover the required range. The gain of the variable-gain amplifier within the vector modulator is adjustable by varying the tail current, thereby enlarging the range of selectable points, improving phase-shifting accuracy, and reducing gain fluctuations. The measurement results show that the proposed active phase shifter achieves an RMS phase error of less than 2° and a gain variation ranging from −1.2 dB to 0.1 dB across a 20 GHz to 30 GHz bandwidth at room temperature. The total chip area is 0.4 mm², with a core area of 0.165 mm², and consumes 19.5 mW of power from a 2.5 V supply. Full article

This paper focuses on the development and experimental validation of a single-phase modular multilevel converter (MMC) based on a battery energy storage system (BESS) for residential uninterruptible power supply (UPS) with two-level active SoC balancing control. The configuration and mathematical modeling of the single-phase MMC-BESS are first presented, followed by the details of the control strategies, including dual-loop output voltage and current control in islanded mode, grid-connected control, circulating current control, and two-level active state-of-charge (SoC) balancing control. The design and optimization of the quasi-proportional-resonant (QPR) controllers were investigated by using particle swarm optimization (PSO). Simulation models were built to explore the operating characteristics of the UPS under islanded mode with an RL load and grid-connected mode and assess the control performance. A 500 W experimental prototype was developed and is herein presented, including results under different operating conditions of the MMC-BESS. The experimental results show that for both RL load and grid-connected tests, balancing was achieved. The response time to track the reference value was two grid periods (0.04 s). In the islanded mode test, the THD was 1.37% and 4.59% for the voltage and current, respectively, while in the grid-connected mode test, these values were 1.72% and 4.24% for voltage and current, respectively. Full article

This paper reviews the current state of research on half-bridge (HB) inverters used in induction heating power supplies, emphasizing their topological structures, output power control methods, and switching strategies. The study explores various control techniques to regulate low power levels in a series resonant inverter (SRI) configured with an HB structure for induction heating applications. Pulse frequency modulation (PFM) is commonly employed to regulate standard power levels by adjusting the operating frequency relative to the resonant frequency. As the operating frequency increases beyond resonance, the output power decreases. However, in certain scenarios, achieving low power levels necessitates high frequencies, which introduces significant control challenges. To address these issues, it is crucial to develop alternative approaches that ensure efficient power reduction, without compromising system performance. This work evaluates and compares multiple solutions tailored for a high-frequency induction heating system delivering 18 kW at an operating frequency of approximately 100 kHz. The study places particular emphasis on optimizing key component sizing and analyzing inverter losses to enhance overall system efficiency and reliability. Full article

The diverse array of sensors deployed on meteorological observation towers, tasked with the observation of meteorological gradients, requires distinct power supplies and effective power regulation. In this article, a multi-frequency, multi-receiver (MFMR) inductively coupled power transfer (ICPT) system using a time-sharing frequency strategy is proposed, which enables coupled power transfer to multiple nodes through only one cable. The time-sharing frequency control (TSFC) method is introduced to produce time-sharing multi-frequency currents. By incorporating a controllable resonant capacitor array at the transmitter, the system can operate at various resonance frequencies over specific intervals, allowing it to supply power to multiple loads with unique resonance frequencies. First, an in-depth analysis of the power transmission characteristics of MFMR-ICPT systems is conducted, with the three-frequency, three-receiver (TFTR) ICPT system circuit serving as an example. The frequency cross-coupling effects are then analyzed, and the TSFC method is explained. Finally, experiments are conducted on a TFTR-ICPT system. The results demonstrated that independent power regulation of multiple loads could be achieved by adjusting the duty cycle of different frequency input voltages through the time-sharing frequency strategy. The system achieved a total power output of 38.7 W, with an efficiency of 64.8%. Full article

Electrostatic actuation is widely employed in microelectromechanical systems (MEMS) due to its distinct advantages. However, it requires high voltage, typically provided by a power supply and a high voltage amplifier, which is limited in gain, especially at high frequencies. Various methods have been proposed to amplify the voltage signal fed into the system by coupling it in series to an LC tank circuit. In this work, we analyze and compare three methods, resonance matching, multi-frequency excitation, and amplitude modulation. We also compare their performance to that of a voltage amplifier. We demonstrate that resonant circuits significantly enhance performance, offering a more effective solution for high-frequency MEMS actuation. Full article

In this study, we present a novel ultra-wideband passive polarization conversion metasurface (PCM) that integrates double V-shaped patterns with circular split-ring resonators. Operating without any external power supply or active components, this design effectively manipulates the polarization state of incident electromagnetic waves. Numerical and experimental results demonstrate that the proposed PCM can convert incident linear polarization into orthogonal states across a wide frequency range of 7.1–22.3 GHz, encompassing the C-, X-, Ku-, and K-bands. A fabricated prototype confirms that the polarization conversion ratio (PCR) exceeds 90% throughout the specified band. Furthermore, we explore an additional application of this passive metasurface for electromagnetic stealth, wherein it achieves over 10 dB of monostatic radar cross-section (RCS) reduction from 7.6 to 21.5 GHz. This broad effectiveness is attributed to strong electromagnetic resonances between the top and bottom layers, as well as the Fabry–Pérot cavity effect, as evidenced by detailed analyses of the underlying physical mechanisms and induced surface currents. These findings confirm the effectiveness of the proposed design and highlight its potential for future technological applications, including 6G communications, radar imaging, anti-interference measures, and electromagnetic stealth. Full article

Microrobots, characterized by their small size, flexibility, and portability, have a diverse range of potential applications. However, microrobots’ actuation (piezoelectric ceramics, dielectric elastomers, ion winds, etc.) often requires a high voltage, typically hundreds of volts. The lithium niobate transformer (LNT), a piezoelectric voltage transformer, presents a promising solution for miniaturizing high-voltage power supplies due to its compact size, low weight, and high step-up ratio. This study explores the effects of structural parameters and external circuits on the resonant frequency and step-up ratio of the LNT through numerical simulations and experiments. The results indicate the following: (1) the second-order longitudinal vibration frequency of the lithium niobate (LN) plate inversely correlates with its length; (2) the thickness and width of the plate have minimal impact on the frequency; (3) the step-up ratio increases as the plate thickness decreases. The experimental results suggest that LN plates with a thickness of 1 mm are preferable due to the fragility of 0.5 mm plates, especially at the output end. Additionally, optimizing the input circuit enhances voltage amplification, allowing the LNT to generate sufficient output voltage for corona discharge. These findings highlight the potential of LNTs for efficiently and reliably powering small-scale devices. Full article

This paper proposes a transient energy auxiliary supply circuit architecture based on resonant switched-capacitor principles, aimed at optimizing the system’s transient response to meet the growing power supply demands. This paper first introduces the relevant principles of resonant switched-capacitor converters. Based on this, a transient energy path topology based on resonant principles is designed to achieve bidirectional, fast, and low electromagnetic interference energy transmission. Corresponding system coordination control strategies and high-precision switch control based on delay lines are proposed for the designed circuit topology. A circuit model is built in SIMPLIS (V8.20a) software for system simulation, and a prototype is built based on FPGA to verify circuit functionality and performance. Experimental results demonstrate that the resonant energy auxiliary circuit can operate in conjunction with a six-phase Buck circuit prototype. Under test conditions of a 500 kHz operating frequency, 6.5 V input voltage, and 0.75 V output voltage, the overshoot voltage is reduced by more than 17% across the entire operating range. When the load steps from 200 A to 20 A, the overshoot voltage is reduced to only 85 mV, a decrease of 27.97%, while the recovery time is 28.8 µs, a reduction of 37.66%. These results confirm that the auxiliary circuit can significantly improve the system’s transient response under large load steps, meeting the design requirements. Full article