Energy based closed form solution of ZCS multiresonantseries-parallel converters

Under-resonant operation of an ideal multi-resonant series-parallel power converter (MRSPC) with a capacitive output filter is modeled in this paper. This operation allows zero current switching (ZCS), which is convenient for bipolar devices. The capacitive output filtering reduces the recovery effect of the rectifier diodes and is suitable for high output voltage applications. A closed-form solution is found for this power converter, based on state space analysis using energy concepts. This approach simplifies the mathematical operations and gives better physical insight of the system variables. Based on the model, the steady-state characteristics of this power converter are derived by a simulation program, which are discussed and compared with the series resonant half-bridge power converter (SRHC). The optimum power converter parameters are found for given design requirements using computerized optimization routines. Several design examples are presented and compared with SRHC. The validity of the model is verified by SPICE simulations     

Integrated control and mechanism design for the variable input-speed servo four-bar linkages

This paper presents an integrated design approach for variable input-speed servo four-bar linkages. In order to satisfy the kinematic requirements, to reduce the shaking force and moment, to improve the speed trajectory tracking performance and to minimize the motor power dissipation, the dimensions of the links, the counterweights, the input-speed trajectory and the controller parameters are considered as the design variables simultaneously. The proposed integrated design approach is introduced and formulated with the optimization design problem. Examples are given to compare the results of the proposed design approach with the other two approaches and demonstrate the feasibility of the proposed integrated design approach.     

A low-cost cellular mobile communication system: a hierarchicaloptimization network resource planning approach

This paper deals with the optimization of the design and radio network resource planning for cellular mobile communication systems. The key element to be considered for mobile network planning is cost. A hierarchical optimization planning method (HOP) is utilized since there are so many factors like system performance, terrain features, base station parameters, and cost factors which are involved in the large-scale system design. We present a three-level optimization approach for designing a cellular mobile system. It determines the cell number, cell site allocation, and the specific base station parameters in order to minimize the total system cost and to comply with the required system performance. The problem is formulated as a large combinatorial optimization model which can determine the optimal number of cells and select the best base stations' locations. The simulated annealing approach is developed to solve the hard combinatorial problem. Simulation results demonstrate the feasibility and effectiveness of the HOP approach for radio network planning     

无人机AC/DC电源的小型化设计

介绍了无人机机载AC/DC电源的发展要求,分析该种电源小型化设计的难点所在,运用系统优化设计的方法分析电源的各功能部件.通过采用替换元件、重建结构、集成电路等手段使电源系统保持成本尽可能低的同时做到体积最小.实现了应用的高效率和灵活性,对我军无人机整体性能的进一步提升具有十分重要的意义.     

Computer-aided optimization of DC/DC converters for automotive applications

This paper investigates computer-aided optimization of DC/DC converters, with a focus on converters for dual-voltage automotive electrical systems. A new CAD optimization approach based on Monte Carlo search methods is introduced which allows the design space to be rapidly explored in an automated fashion and the most optimal designs and design approaches to be identified. The optimization approach also allows the effects of variations in design specifications on the cost, weight, and volume of an optimized converter to be readily determined. A prototype converter designed using this optimization procedure is evaluated and compared to a converter designed by conventional means.     

Application of nonlinear design optimization for power convertercomponents

A computer-aided-design approach for power converter components is described. A designer with a minimum of programming and optimization experience can interface with nonlinear optimization routines to rapidly perform design trade-offs that would be impossible by hand. A power converter design using MOSFET and bipolar-junction-transistor (BJT) switches is shown to illustrate the power of optimization routines in power electronics. Realistic design values and available vendor components can be incorporated in a design without using an extensive database program structure. A practical example is given with experimental data to verify the accuracy and usefulness of optimization software     

Level conversion for dual-supply systems

Dual-supply voltage design using a clustered voltage scaling (CVS) scheme is an effective approach to reduce chip power. The optimal CVS design relies on a level converter implemented in a flip-flop to minimize energy, delay, and area penalties due to level conversion. Additionally, circuit robustness against supply bounce is a key property that differentiates good level converter design. Novel flip-flops presented in this paper incorporate a half-latch level converter and a precharged level converter. These flip-flops are optimized in the energy-delay design space to achieve over 30% reduction of energy-delay product and about 10% savings of total power in a CVS design as compared to the conventional flip-flop. These benefits are accompanied by 24% flip-flop robustness improvement leading to 13% delay spread reduction in a CVS critical path. The proposed flip-flops also show 18% layout area reduction. Advantages of level conversion in a flip-flop over asynchronous level conversion in combinational logic are also discussed in terms of delay penalty and its sensitivity to supply bounce.     

Umformerwerksoptimierung — Momentanoptimierung im Bahnstromversorgungsnetz

This article deals with short-term-optimization. The goal of the optimization is to minimize the total cost of imported (exported) energy from the public grid via converter board by using unit commitment and optimal power flow. Based on the results of the state estimator and the load forecast the optimal generation schedule for the rotary converters will be determined several hours into the future subject to several constraints.     

Control Design of a Three-Phase Matrix-Converter-Based AC–AC Mobile Utility Power Supply

This paper describes the control analysis and design of an ac-to-ac three-phase mobile utility power supply using a matrix converter capable of high-quality 50-, 60-, and 400-Hz output voltage and reduced input harmonic distortion. Instead of the traditional structure employing a diode bridge rectifier, a dc link and a pulsewidth-modulated inverter, a three-phase-to-three-phase direct ac-ac (matrix) converter has been used as the power-conditioning core of the system, working in conjunction with input and output LC low-pass filters. An optimizing control design method using a genetic algorithm approach has been used, which yields designs to minimize a cost function, taking into account transient and steady-state output voltage performance targets, together with robustness to different operative conditions and system parameters drift. Simulation and experimental tests have demonstrated that the system meets the power-quality requirements of the application.     

Energy Management Power Converters in Hybrid Electric and Fuel Cell Vehicles

Using a bidirectional dc-dc converter along with low-voltage energy storage for the high-voltage dc bus and traction motor drives has been a prominent option for hybrid electric and fuel cell vehicles. This paper will describe the significance of energy management power converters and their circuit topology options for efficiency, size, and cost considerations. Whether isolated or nonisolated, soft switching techniques have been widely used in high-power bidirectional dc-dc converters. Through some design examples, the component selection and circuit design optimization are discussed, and their efficiency evaluation results are also given. Major difficulties of developing a high-power bidirectional dc-dc converter are found in lack of high-power passive components and lack of multiphase dc-dc controllers. More development work needs to be done in these areas     

Power electronic converters for switched reluctance drives

A number of power electronic converter circuits exist for switched reluctance motor (SRM) drives which are generally applicable to most loads. A larger number of circuits exist which are suitable for particular niche applications, but which have the potential to be the most cost-effective within that niche. Due to the variable methods of operation of these circuits and the rapid progress in this field, comparisons of these circuits have so far been limited. This paper attempts to bring together the sum total of power converter topologies so far published for SRM drives. A novel classification methodology is presented. The power converters are compared using a straightforward total semiconductor VA per phase sum, and the relative cost of the drive system elements is considered     

System optimization with component reliability estimation uncertainty: a multi-criteria approach

Summary & Conclusions-This paper addresses system reliability optimization when component reliability estimates are treated as random variables with estimation uncertainty. System reliability optimization algorithms generally assume that component reliability values are known exactly, i.e., they are deterministic. In practice, that is rarely the case. For risk-averse system design, the estimation uncertainty, propagated from the component estimates, may result in unacceptable estimation uncertainty at the system-level. The system design problem is thus formulated with multiple objectives: (1) to maximize the system reliability estimate, and (2) to minimize its associated variance. This formulation of the reliability optimization is new, and the resulting solutions offer a unique perspective on system design. Once formulated in this manner, standard multiple objective concepts, including Pareto optimality, were used to determine solutions. Pareto optimality is an attractive alternative for this type of problem. It provides decision-makers the flexibility to choose the best-compromise solution. Pareto optimal solutions were found by solving a series of weighted objective problems with incrementally varied weights. Several sample systems are solved to demonstrate the approach presented in this paper. The first example is a hypothetical series-parallel system, and the second example is the fault tolerant distributed system architecture for a voice recognition system. The results indicate that significantly different designs are obtained when the formulation incorporates estimation uncertainty. If decision-makers are risk averse, and wish to consider estimation uncertainty, previously available methodologies are likely to be inadequate.     

Thermal modeling of high frequency DC–DC switching modules: Electromagnetic and thermal simulation of magnetic components

This work focuses on the accurate thermal modeling of magnetic components for power converters. The inductors of a 1.8 MHz DC–DC switching converter are simulated using the Finite-Element (FE) approach with a three-step procedure: (i) electrical simulation for Joule power loss; (ii) electromagnetic simulation for core losses and eddy currents; (iii) thermal simulation for temperature distribution calculation. The magnetic component models can be used in the full converter FE thermal simulation for design optimization and estimation of reliability hazards.     

Development of a low cost fuel cell inverter system with DSP control

In this paper, the development of a low cost fuel cell inverter system is detailed. The approach consists of a three-terminal push-pull dc-dc converter to boost the fuel cell voltage (48V) to /spl plusmn/200 VDC. A four switch [insulated gate bipolar transistor (IGBT)] inverter is employed to produce 120-V/240-V, 60-Hz ac outputs. High performance, easy manufacturability, lower component count, safety and cost are addressed. Protection and diagnostic features form an important part of the design. Another highlight of the proposed design is the control strategy, which allows the inverter to adapt to the requirements of the load as well as the power source (fuel cell). A unique aspect of the design is the use of the TMS320LF2407 DSP to control the inverter. Two sets of lead-acid batteries are provided on the high voltage dc bus to supply sudden load demands. Efficient and smooth control of the power drawn from the fuel cell and the high voltage battery is achieved by controlling the front end dc-dc converter in current mode. The paper details extensive experimental results of the proposed design on Department of Energy (DoE) National Energy Technology Laboratory (NETL) fuel cell.     

A high frequency AC/DC converter with unity power factor andminimum harmonic distortion

A novel forced commutated AC/DC converter and control strategy is proposed that is able to draw nearly sinusoidal currents at unity power factor from three-phase power lines. The power factor is controlled by adjusting the relative position of the fundamental component of an optimized pulse-width-modulation (PWM) type voltage with respect to the supply voltage. Current harmonic distortion is minimized by the use of optimized firing angles for the converter at a frequency where gate turn-off thyristors (GTOs) can be used. This feature makes this approach attractive at power levels of 100 kW to 600 kW. An 8096 microcontroller is used to minimize the interface hardware requirements. The theoretical analysis of the converter, the control energy, and experimental results for a low-power prototype are presented     

Switched scalar quantizers for hidden Markov sources

An algorithm for designing switched scalar quantizers for hidden Markov sources is described. The design problem is cast as a nonlinear optimization problem. The optimization variables are the thresholds and reproduction levels for each quantizer and the parameters defining the next-quantizer map. The cost function is the average distribution incurred by the system in steady-state. The next-quantizer map is treated as a stochastic map so that all of the optimization variables are continuous-valued, allowing the use of a gradient-based optimization procedure. This approach solves a major problem in the design of switched scalar quantizing systems, namely, that of determining an optimal next-quantizer decision rule. Details are given for computing the cost function and its gradient for weighted-squared-error distortion. Simulation results which compare the new system to current systems show that the present system performs better. It is observed that the optimal system can in fact have a next-quantizer map with stochastic components     

A new method of analysis for PWM switching power converters

A new method of analysis for pulse-width modulation (PWM) switching power converters is presented. It allows one to find an approximate periodic solution for the converter vector state variable. The converter is modelled by a differential equation with periodic coefficients. This equation is substituted by an equivalent system of linear differential equations with constant coefficients. Only the forced (steady-state) solutions should be found for each equation of this system. The equations are solved in sequence. The final steady-state solution of the PWM differential equation is obtained as the sum of these forced solutions. The method allows one to find the converter dc transfer function and efficiency, to evaluate their frequency dependences, and to find the critical frequency and ripple. The first three equations of the equivalent system are usually adequate for practical purposes, and these equations are obtained by an easy formal procedure. One can also obtain the dynamic equation of the state variable dc component, and calculate the converter line to output and duty cycle to output transfer functions. A boost converter is used as an example to confirm the analytical results by numerical simulation.     

Response Surface Based Optimization Approach for Thermal Placement Design of Chips in Multiple-Chip Modules

This paper attempts to perform thermal enhancement of planar multiple-chip modules (MCMs) containing a number of chips of equal and/or unequal power through optimal chip placement design. To achieve the goal, an effective design approach is presented for the thermal design optimization problems in the context of models of placement of chips in MCMs. The approach combines the use of the currently proposed response surface (RS) based methodology, which is an optimization algorithm and a finite element modeling technique. The proposed RS-based methodology is used for creating a macro mathematical expression of the design objective of the thermal optimization problem, i.e., the total chip junction temperature of the system, associated with the design parameters, including the chip location and power. The validity of the mathematical expressions constructed is verified through two approaches. Furthermore, to make the constructed mathematical expression more compact while maintaining the associated solution accuracy, the backward variable elimination technique is employed. The effectiveness of the proposed design optimization methodology is demonstrated through several design case studies involving planar plastic ball grid array type MCMs. It is found that the proposed RS-based methodology could accurately define the macro mathematical model of the total system chip junction temperature in terms of the chip location and power. In addition, results show that the current optimal chip placement design can provide a minimal system temperature.     

Unified modeling of hybrid electric vehicle drivetrains

Hybridizing automotive drivetrains, or using more than one type of energy converter, is considered an important step toward very low pollutant emission and high fuel economy. The automotive industry and governments in the United States, Europe, and Japan have formed strategic initiatives with the aim of cooperating in the development of new vehicle technologies. Efforts to meet fuel economy and exhaust emission targets have initiated major advances in hybrid drivetrain system components, including: high-efficiency high-specific power electric motors and controllers; load-leveling devices such as ultracapacitors and fly-wheels; hydrogen and direct-methanol fuel cells; direct injection diesel and Otto cycle engines; and advanced batteries. The design of hybrid electric vehicles is an excellent example of the need for mechatronic system analysis and design methods. If one is to fully realize the potential of using these technologies, a complete vehicle system approach for component selection and optimization over typical driving situations is required. The control problems that arise in connection with hybrid power trains are significant and pose additional challenges to power-train control engineers. The principal aim of the paper is to propose a framework for the analysis, design, and control of optimum hybrid vehicles within the context of energy and power flow analysis. The approaches and results presented in the paper are one step toward the development of a complete toolbox for the analysis and design of hybrid vehicles     

Analysis and design of clamped-mode resonant converters withvariable load

In this paper, a design procedure for clamped-mode resonant converters working with variable load is proposed and analyzed. The operation of these converters with general parallel or series loads is reviewed first. The operation of the transistors as zero-voltage switches is identified and characterized as mode A. Mode A is preferred to simplify the implementation of the power switches and to increment the converter efficiency. As a case study, the design of an RF power amplifier is presented. The amplifier is connected to a variable load with reactive characteristics, through a low-pass filter of three elements. The validity of the proposed design approach is verified with an experimental setup