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This paper is the second in a series of two dealing with the spatial optimization of the heat exchanger temperature profiles of exothermic tubular reactors under the assumption of steady-state and plug flow characteristics. The minimum principle of Pontryagin (optimal control theory) is applied in a straightforward, analytical sense. To enable a trade-off between process performance and global heat...
This series of two papers deals with the spatial optimization of the heat exchanger temperature profile of an exothermic tubular reactor under the assumption of steady state and plug flow characteristics. The minimum principle of Pontryagin (optimal control theory) is applied in a straightforward, analytical sense. To enable a trade-off between process performance and heat loss a combined cost criterion...
The paper presents a nodal technique for modeling a large Pressurized Heavy Water Reactor (PHWR). Model equations have been derived from the two group diffusion equations and validated by applying it to a benchmark problem for a large heavy water reactor. The computational results obtained from the model are compared with the benchmark results.
Highly nonlinear and open-loop unstable processes pose serious difficulties to the implementation of optimal control solutions, such as Model Predictive Control (MPC). An example of such processes is the Tennessee Eastman model. Here we show that by proper combination of the optimization algorithm with additional intermediate layers of control, most of the ill-conditioning can be avoided, without...
In this paper a very high gain step up DC-DC converter is proposed. Maximum voltage gain in conventional boost converter like, switched inductor converter, switched capacitor converter, cascaded boost converter etc. are limited due to extreme duty cycle (i.e. duty cycle near to unity). Operation at extreme duty cycle leads to, serious reverse recovery problem at the switches, high conduction losses,...
Potential of bidirectional Split-Pi converter is yet to be exploited. Its unique features like bidirectional property, option to employ in multiphase systems and smaller ratings of passive elements provides liberty to use it in applications demanding high power density such as in hybrid electric vehicles, renewable energy, aerospace, military etc. In this paper dynamic model of Split-Pi converter...
Output dc voltage from Fuel Cell (FC)/Photo Voltaics (PV) needs to be conditioned and converted into ac form before integrating to grid. Normally, two stage converters are used for this purpose. Two stage converters have several disadvantages like low efficiency, more number of components, big size, etc. especially when they are operated at low input voltages. In this paper, a coupled inductor based...
A detailed small signal analysis and a closed loop control design of naturally commutated current-fed dual active bridge (CFDAB) dc/dc converter are presented. Proposed converter is suitable for fuel cell vehicle between traction inverter and batteries. State-space averaging technique is used to derive the small signal model. A closed two-loop controller is designed and implemented on mixed signal...
Due to the focus on clean and green environment, the interest on electrification of existing transportation system is increasing. In Hybrid Electric Vehicle (HEV), the "idle-stop" and hence fuel economy is achieved by using integrated starter generator (ISG). This paper discusses the comparative evaluation of active bidirectional converter based ISG and passive quasi-Z source inverter (qZSI)...
The low and medium voltage renewable energy based dc distribution systems are catching increased attention world-wide due to their inherent benefits over ac systems. Higher efficiency, simple control, more suitable for integration of the sources producing dc power, are some of the main benefits of the dc systems. However, these systems are prone to serious stability issues caused by the constant power...
This paper presents a configuration for the high gain boost converter with coupled inductor and switched capacitor and also gives the improved version for the proposed configuration. The proposed converter has wide input voltage band-width due to its high gain feature. The given converter also has optimum number of components that are optimally utilized. The proposed converter uses coupled inductor...
This paper demonstrates some fundamentals concerning the study of the Fractional order Transmission Line (FTL) operation. A numerical algorithm applied to study the transient analysis is shown describing the abnormal diffusion that appears in the operation of the TL. According to the steady state analysis of the FTL operation, the superior advantages over the conventional domain of imposing the fractional...
Because of its inherent safety feature and potential economic competitiveness, modular high temperature gas-cooled reactor (MHTGR) has been seen as one of the best candidate for building the next generation nuclear energy systems. As a typical small modular reactor (SMR), MHTGR can be incorporated with new energy resources to build micro-grids, and can also be used to build large nuclear energy systems...
This paper describes a four quadrants converter system for the international fusion tokamak device (ITER) which is now under construction in the south of France. The ITER poloidal field (PF) converter system is thyristor-based and rated for 82 MVA, providing up to ±1.05 kV/± 55 kA dc power to the superconducting magnets to generate a controlled rotating magnetic field for nuclear fusion reactions...
This paper proposes a new modeling method for buck converter. The new modeling method, named bi-switching status method (BSM), for buck converter is obtained via the propositional calculus and linear constrain. Based on the mixed logical dynamical (MLD) model, BSM model of buck converter is obtained. Compared with other modeling methods, such as MLD method and state-space averaging method, streamlined...
As for high power plasma power supply, due to high efficiency and flexibility, multi-channel interleaved multi-stage paralleled Buck DC-DC Converter becomes the first choice. In the paper, two-channel interleaved two- stage paralleled Buck DC-DC Converter powered by three-phase AC power supply is selected as research subject, dedicated for the use of plasma cutting machine of 2×45kW, and the passivity-based...
In order to solve the design problem of coupled inductor in multiphase interleaving bidirectional DC/DC convertor, the universal design criterion of coupled inductor with general applicability was proposed. The Buck+Boost interleaving and magnetically integrated bidirectional DC/DC converter was studied under Buck mode with all inductors coupled symmetrically. The universal design criterion of coupled...
In this paper, a current-feed resonant two-switch forward DC-DC Transformer (DCX) is proposed for high-efficiency and high-density unregulated bus converter applications. With a resonant capacitor in series with the leakage inductance of the transformer, ZCS turn-on and nearly ZCS turn-off can be achieved for the primary switches and there is no body diode and reverse recovery losses in the SR. Meanwhile,...
In this paper, an on-board charger for electric vehicle, with two-stage power converter, is designed. Firstly, a single-phase Boost-APFC (Active Power Factor Correction) circuit controlled by a one-cycle controller is designed as the front state converter. Compared to the traditional APFC circuit, the One-cycle controller is constructed without considering the multiplier and AC line voltage sensing...
This article presents the fundamental theory of inverse optimal control problems and its application in output voltage regulation of power converter circuits. An inverse optimal control problem avoids the explicit solution of the Hamilton-Jacobi-Bellman equation that appears in the formulation of an optimal control problem. Some analytical and numerical developments are performed here in order to...
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