1,931 research outputs found
Cyclic-averaging for high-speed analysis of resonant converters
AbstractâThe paper describes the development and application
of a cyclic-averaging technique for the rapid analysis of
high-order resonant power converters. To provide a focus to the paper, particular emphasis is given to a 3rd-order LCC voltage output converter topology. The proposed methodology predicts steady-state voltages and currents throughout the circuit, and provides estimates of the stresses on the resonant circuit components. State-space simulations and experimental results from a 350 V-input/150 V-output converter are used to demonstrate a prediction accuracy comparable with time-domain integration-based
techniques is achievable, while requiring only 1/10,000th of the computation time. In addition, a comparison with Spice simulation results shows that cyclic averaging provides commensurate predictions of voltage and current stresses on the resonant circuit components. Issues arising from the stray capacitance associated with the resonant inductor, and the corresponding sensitivity of the predicted output voltage, are also considered
Analysis of CLL voltage-output resonant converters using describing functions
A new ac equivalent circuit for the CLL voltage output resonant converter is presented, that offers improved
accuracy compared with traditional FMA-based techniques. By employing describing function techniques, the nonlinear interaction of the parallel inductor, rectifier and load is replaced by a complex impedance, thereby facilitating the use of ac equivalent circuit analysis methodologies. Moreover, both continuous and discontinuous rectifier-current operating conditions are addressed. A generic normalized analysis of the converter is also presented. To further aid the designer, error maps are used to demonstrate the boundaries for providing accurate behavioral predictions. A comparison
of theoretical results with those from simulation studies and experimental measurements from a prototype converter, are also included as a means of clarifying the benefits of the proposed techniques
One-cycle control of switching converters
A new large-signal nonlinear control technique is proposed to control the duty-ratio d of a switch such that in each cycle the average value of a switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient. One-cycle control rejects power source perturbations in one switching cycle; the average value of the switched variable follows the dynamic reference in one switching cycle; and the controller corrects switching errors in one switching cycle. There is no steady-state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with a constant frequency buck converter have demonstrated the robustness of the control method and verified the theoretical predictions. This new control method is very general and applicable to all types of pulse-width-modulated, resonant-based, or soft-switched switching converters for either voltage or current control in continuous or discontinuous conduction mode. Furthermore, it can be used to control any physical variable or abstract signal that is in the form of a switched variable or can be converted to the form of a switched variable
Self-oscillating control methods for the LCC current-output resonant converter
AbstractâA strategy for self-oscillating control of LCC current-output resonant converters, is presented, based on varying the phase-angle between the fundamental of the input voltage and current. Unlike other commonly employed control methodologies,the proposed technique is shown to provide a convenient, linear system input-output characteristic suitable for the design of regulators.
The method is shown to have a similar effect as controlling
the dc-link supply voltage, in terms of output-voltage/current control. The LCC converter variant is used as an application focus for demonstrating the presented techniques, with simulation and experimental measurements from a prototype converter being used to show the practical benefits. Third-order small and large-signal models are developed, and employed in the formulation of robust output-voltage and output-current control schemes.
However, notably, the presented techniques are ultimately generic and readily applicable to other resonant converter variants
Novel active function blocks and their applications in frequency filters and quadrature oscillators
KmitoÄtovĂ© filtry a sinusoidnĂ oscilĂĄtory jsou lineĂĄrnĂ elektronickĂ© obvody, kterĂ© jsou pouĆŸĂvĂĄny v ĆĄirokĂ© oblasti elektroniky a jsou zĂĄkladnĂmi stavebnĂmi bloky v analogovĂ©m zpracovĂĄnĂ signĂĄlu. V poslednĂ dekĂĄdÄ pro tento ĂșÄel bylo prezentovĂĄno velkĂ© mnoĆŸstvĂ stavebnĂch funkÄnĂch blokĆŻ. V letech 2000 a 2006 na Ăstavu telekomunikacĂ, VUT v BrnÄ byly definovĂĄny univerzĂĄlnĂ proudovĂœ konvejor (UCC) a univerzĂĄlnĂ napÄt'ovĂœ konvejor (UVC) a vyrobeny ve spoluprĂĄci s firmou AMI Semiconductor Czech, Ltd. OvĆĄem, stĂĄle existuje poĆŸadavek na vĂœvoj novĂœch aktivnĂch prvkĆŻ, kterĂ© nabĂzejĂ novĂ© vĂœhody. HlavnĂ pĆĂnos prĂĄce proto spoÄĂvĂĄ v definici dalĆĄĂch pĆŻvodnĂch aktivnĂch stavebnĂch blokĆŻ jako jsou differential-input buffered and transconductance amplifier (DBTA), current follower transconductance amplifier (CFTA), z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), generalized current follower differential input transconductance amplifier (GCFDITA), voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), a minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). PomocĂ navrĆŸenĂœch aktivnĂch stavebnĂch blokĆŻ byly prezentovĂĄny pĆŻvodnĂ zapojenĂ fĂĄzovacĂch ÄlĂĄnkĆŻ prvnĂho ĆĂĄdu, univerzĂĄlnĂ filtry druhĂ©ho ĆĂĄdu, ekvivalenty obvodu typu KHN, inverznĂ filtry, aktivnĂ simulĂĄtory uzemnÄnĂ©ho induktoru a kvadraturnĂ sinusoidnĂ oscilĂĄtory pracujĂcĂ v proudovĂ©m, napÄt'ovĂ©m a smĂĆĄenĂ©m mĂłdu. ChovĂĄnĂ navrĆŸenĂœch obvodĆŻ byla ovÄĆena simulacĂ v prostĆedĂ SPICE a ve vybranĂœch pĆĂpadech experimentĂĄlnĂm mÄĆenĂm.Frequency filters and sinusoidal oscillators are linear electric circuits that are used in wide area of electronics and also are the basic building blocks in analogue signal processing. In the last decade, huge number of active building blocks (ABBs) were presented for this purpose. In 2000 and 2006, the universal current conveyor (UCC) and the universal voltage conveyor (UVC), respectively, were designed at the Department of Telecommunication, BUT, Brno, and produced in cooperation with AMI Semiconductor Czech, Ltd. There is still the need to develop new active elements that offer new advantages. The main contribution of this thesis is, therefore, the definition of other novel ABBs such as the differential-input buffered and transconductance amplifier (DBTA), the current follower transconductance amplifier (CFTA), the z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), the generalized current follower differential input transconductance amplifier (GCFDITA), the voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), and the minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). Using the proposed ABBs, novel structures of first-order all-pass filters, second-order universal filters, KHN-equivalent circuits, inverse filters, active grounded inductance simulators, and quadrature sinusoidal oscillators working in the current-, voltage-, or mixed-mode are presented. The behavior of the proposed circuits has been verified by SPICE simulations and in selected cases also by experimental measurements.
Stability Study and Nonlinear Analysis of DC-DC Power Converters with Constant Power Loads at the Fast Timescale
Rapidly growing distributed renewable networks make an increasing demand on various types of power converters to feed different loads. Power converters with constant power load are one typical configuration that can degrade the stability of the power conversion system due to the negative impedance characteristic. This paper presents a nonlinear analysis method using the developed complete-cycle solution matrix method by transforming the original linear time-variant system into a summation of segmented linear time-invariant systems. Thus, the stability of the nonlinear system can be studied using a series of the corresponding state transition matrix and saltation matrix. As this derived matrix contains all the comprehensive information relating to the systemâs stability, the influence of the constant power load to systemâs fast-timescale stability in both continuous conduction mode and the discontinuous conduction mode can be fully investigated and analyzed. The phenomena of fast-timescale instability around switching frequency for power converters with a constant power load are observed and investigated numerically. Finally, experimental results have proven the analysis and verified the effectiveness of the developed method
Efficient and Robust Simulation, Modeling and Characterization of IC Power Delivery Circuits
As the Mooreâs Law continues to drive IC technology, power delivery has become one
of the most difficult design challenges. Two of the major components in power delivery are
DC-DC converters and power distribution networks, both of which are time-consuming to
simulate and characterize using traditional approaches. In this dissertation, we propose a
complete set of solutions to efficiently analyze DC-DC converters and power distribution
networks by finding a perfect balance between efficiency and accuracy.
To tackle the problem, we first present a novel envelope following method based on
a numerically robust time-delayed phase condition to track the envelopes of circuit states
under a varying switching frequency. By adopting three fast simulation techniques, our
proposed method achieves higher speedup without comprising the accuracy of the results.
The robustness and efficiency of the proposed method are demonstrated using several DCDC
converter and oscillator circuits modeled using the industrial standard BSIM4 transistor
models. A significant runtime speedup of up to 30X with respect to the conventional
transient analysis is achieved for several DC-DC converters with strong nonlinear switching
characteristics.
We then take another approach, average modeling, to enhance the efficiency of analyzing
DC-DC converters. We proposed a multi-harmonic model that not only predicts the
DC response but also captures the harmonics of arbitrary degrees. The proposed full-order
model retains the inductor current as a state variable and accurately captures the circuit
dynamics even in the transient state. Furthermore, by continuously monitoring state variables,
our model seamlessly transitions between continuous conduction mode and discontinuous
conduction mode. The proposed model, when tested with a system decoupling
technique, obtains up to 10X runtime speedups over transistor-level simulations with a maximum output voltage error that never exceeds 4%.
Based on the multi-harmonic averaged model, we further developed the small-signal
model that provides a complete characterization of both DC averages and higher-order
harmonic responses. The proposed model captures important high-frequency overshoots
and undershoots of the converter response, which are otherwise unaccounted for by the
existing techniques. In two converter examples, the proposed model corrects the misleading
results of the existing models by providing the truthful characterization of the overall
converter AC response and offers important guidance for converter design and closed-loop
control.
To address the problem of time-consuming simulation of power distribution networks,
we present a partition-based iterative method by integrating block-Jacobi method with
support graph method. The former enjoys the ease of parallelization, however, lacks a
direct control of the numerical properties of the produced partitions. In contrast, the latter
operates on the maximum spanning tree of the circuit graph, which is optimized for
fast numerical convergence, but is bottlenecked by its difficulty of parallelization. In our
proposed method, the circuit partitioning is guided by the maximum spanning tree of the
underlying circuit graph, offering essential guidance for achieving fast convergence. The
resulting block-Jacobi-like preconditioner maximizes the numerical benefit inherited from
support graph theory while lending itself to straightforward parallelization as a partitionbased
method. The experimental results on IBM power grid suite and synthetic power grid
benchmarks show that our proposed method speeds up the DC simulation by up to 11.5X
over a state-of-the-art direct solver
Modeling and Analysis of Power Processing Systems (MAPPS), initial phase 2
The overall objective of the program is to provide the engineering tools to reduce the analysis, design, and development effort, and thus the cost, in achieving the required performances for switching regulators and dc-dc converter systems. The program was both tutorial and application oriented. Various analytical methods were described in detail and supplemented with examples, and those with standardization appeals were reduced into computer-based subprograms. Major program efforts included those concerning small and large signal control-dependent performance analysis and simulation, control circuit design, power circuit design and optimization, system configuration study, and system performance simulation. Techniques including discrete time domain, conventional frequency domain, Lagrange multiplier, nonlinear programming, and control design synthesis were employed in these efforts. To enhance interactive conversation between the modeling and analysis subprograms and the user, a working prototype of the Data Management Program was also developed to facilitate expansion as future subprogram capabilities increase
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