Hybrid Circuit Model Research Articles

Control Development and Fault Current Commutation Test for the EDISON Hybrid Circuit Breaker

The DC circuit breaker is an indispensable building block for DC network systems. Hybrid circuit breakers that combine mechanical and solid-state switches have more potential to be utilized in DC distribution networks because of their lower conduction losses and fast interrupt speed. The efficient energy DC interrupter with surge protection (EDISON) removes any solid-state circuit in the main current path, thereby substantially reducing the conduction losses during normal operations. However, it requires a dedicated control with fast dynamics because any false triggering of the mechanical switch or solid-state switches of the breaker would lead to a commutation failure and a potential unquenchable arc. This paper proposes a finite-state-machine (FSM) based control scheme that guarantees an accurate and fast control response during a fault event. Due to this fast response requirement, a dual-core-CPU-based control architecture is applied featuring parallel taskings and negligible communication delays between the two cores. Furthermore, a control-law-accelerator (CLA) is employed to further reduce the latency of the program execution by 33%. The controller hardware-in-the-loop (CHIL) model of the EDISON breaker is implemented in OPAL-RT to verify the control scheme and de-risk the prototype test. A fifth-order RLC network is developed to characterize the mechanical switch behavior such that the hybrid circuit model can be simulated in the CHIL solely by circuit components. Finally, the proposed control scheme is implemented and validated in a prototype test with a 3 kA interrupting current and a 60 A/μs current commutation rate.

Measurement-Induced Transition in Long-Range Interacting Quantum Circuits.

The competition between scrambling unitary evolution and projective measurements leads to a phase transition in the dynamics of quantum entanglement. Here, we demonstrate that the nature of this transition is fundamentally altered by the presence of long-range, power-law interactions. For sufficiently weak power laws, the measurement-induced transition is described by conformal field theory, analogous to short-range-interacting hybrid circuits. However, beyond a critical power law, we demonstrate that long-range interactions give rise to a continuum of nonconformal universality classes, with continuously varying critical exponents. We numerically determine the phase diagram for a one-dimensional, long-range-interacting hybrid circuit model as a function of the power-law exponent and the measurement rate. Finally, by using an analytic mapping to a long-range quantum Ising model, we provide a theoretical understanding for the critical power law.

Measurement-induced purification in large- N hybrid Brownian circuits

Competition between unitary dynamics that scrambles quantum information nonlocally and local measurements that probe and collapse the quantum state can result in a measurement-induced entanglement phase transition. Here we study this phenomenon in an analytically tractable all-to-all Brownian hybrid circuit model composed of qubits. The system is initially entangled with an equal sized reference, and the subsequent hybrid system dynamics either partially preserves or totally destroys this entanglement depending on the measurement rate. Our approach can access a variety of entropic observables which are distinguished by the averaging procedure, and for concreteness we focus on a particular purity quantity for which the averaging is particularly simple. We represent the purity as a path integral coupling four replicas with twisted boundary conditions. Saddle-point analysis reveals a second-order phase transition corresponding to replica permutation symmetry breaking below a critical measurement rate. The transition is mean-field-like and we characterize the critical properties near the transition in terms of a simple Ising field theory in $0+1$ dimensions. In addition to studying the purity of the entire system, we study subsystem purities and relate these results to manifestations of quantum error correction in the model. We also comment on the experimental feasibility for simulating this averaged purity, and corroborate our results with exact diagonalization for modest system sizes.

Modeling the effect of cochlear windows activity on reverse stimulation under the role of physiological third windows

The cochlear windows consist of the round window (RW) and the oval window (OW). These two openings connect the cochlea and the middle ear; its activity plays a vital role in sound transmission into the cochlea. However, it is difficult to capture a brief description of how cochlear windows activity affects reverse stimulation with physiological third windows. In the present study, a hybrid circuit model considering the vestibular and cochlear aqueducts was used to investigate the relationship between cochlear windows activity and reverse stimulation. Meanwhile, a finite element (FE) model of the RW was established to perform stiffness calibration on the RW thickening. Then, middle ear disorders involving the activity of the RW and the OW were simulated: otosclerosis and otitis media. Finally, the intracochlear differential pressure transfer function were calculated to predict the influence of cochlear windows activity on sound perception under reverse stimulation. The results show that the resonant response of the auditory system complicates the effects of cochlear windows activity on reverse sound transmission. Moreover, the physiological third windows produce volume velocity shunt flow, which mitigates the deterioration caused by the reduced cochlear windows activity during reverse stimulation.

1-D Large Signal Model of Folded-Waveguide Traveling Wave Tubes

A recently published hybrid circuit model for folded-waveguide slow wave structures has been implemented in the 1-D large signal code CHRISTINE. The resulting code is applied to a design for a G-band (220 GHz) folded-waveguide traveling wave tube. Results of small and large signal gain are compared with those from TESLA, a 2-D code using the same circuit model. Conditions for accuracy of the 1-D model are illustrated and explained. The effects of an offset beam tunnel on circuit dispersion and amplifier stability are illustrated using the CHRISTINE code.

Reentrant excitation in an analog-digital hybrid circuit model of cardiac tissue

We propose an analog-digital hybrid circuit model of one-dimensional cardiac tissue with hardware implementation that allows us to perform real-time simulations of spatially conducting cardiac action potentials. Each active nodal compartment of the tissue model is designed using analog circuits and a dsPIC microcontroller, by which the time-dependent and time-independent nonlinear current-voltage relationships of six types of ion channel currents employed in the Luo-Rudy phase I (LR-I) model for a single mammalian cardiac ventricular cell can be reproduced quantitatively. Here, we perform real-time simulations of reentrant excitation conduction in a ring-shaped tissue model that includes eighty nodal compartments. In particular, we show that the hybrid tissue model can exhibit real-time dynamics for initiation of reentries induced by uni-directional block, as well as those for phase resetting that leads to annihilation of the reentry in response to impulsive current stimulations at appropriate nodes and timings. The dynamics of the hybrid model are comparable to those of a spatially distributed tissue model with LR-I compartments. Thus, it is conceivable that the hybrid model might be a useful tool for large scale simulations of cardiac tissue dynamics, as an alternative to numerical simulations, leading toward further understanding of the reentrant mechanisms.

Whip–PIFA combination for handset application: A hybrid circuit model and full‐wave analysis

AbstractIn this paper, a circuit model is developed in RF ADS in order to simulate the coupling effect of a retracted whip on a planar inverted‐F antenna (PIFA) for wireless‐handset application. The PIFA is designed as the main antenna of the handset to cover the 800‐MHz (824–894 MHz) and 1900‐MHz (1850–1990 MHz) bands. A parasitic whip antenna is used to improve the performance of the PIFA, especially when the handset is used against the human head. In such a whip–PIFA combination environment, the retracted whip will degrade the PIFA performance if it is not designed carefully. The purpose of this paper is to present an efficient method to optimize the PIFA performance when the whip antenna is in the retracted position. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 210–215, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20590