Two-phase forward converter using an integrated magnetic component

An interleaved two-phase forward converter using an integrated magnetic component is proposed for telecommunication and computer applications. The integrated magnetic component consists of two step-down transformers and two output-filtering inductors on a single magnetic core. The z-parameter (gyrator) model and the equivalent-circuit model of the integrated magnetic component are presented. The circuit operation and design criteria of the proposed converter are described. All theoretical analyses are verified by simulated and experimental results.     

Table-Aided Design of the Energy-Storage Reactor in DC-to-DC Converters

A new procedure for the selection of magnetic cores for use in energy-storage dc-to-dc power converters that eliminates the need for an automated computer search algorithm and stored data file is presented. The converter configurations included in the procedure are the three commonly encountered single-winding converters for voltage stepup, for current stepup and voltage stepup/current stepup, and for the two-winding converter for voltage stepup/current stepup. For each converter configuration, three types of controllers are considered: constant-frequency, constant on-time, and constant off-time. Using concepts developed from analyses of these converters by considering the transfer of energy by means of an energystorage inductor or transformer, a special table of parameters calculated from magnetic core data is constructed, which leads to a considerably simplified design procedure.     

Power tracking for nonlinear PV sources with coupled inductor SEPIC converter

The photovoltaic (PV) generator exhibits a nonlinear i-v characteristic and its maximum power (MP) point varies with solar insolation. In this paper, a V2-based MP point tracking (MPPT) scheme is developed using a buck-boost transformation topology. Although several buck-boost transformation topologies are available we have considered here a coupled inductor SEPIC converter for experimentation. To achieve almost ripple-free array current we have used ripple steering phenomena with the help of integrated inductor. This integrated inductor not only reduces the magnetic core requirements but also improves converter performance. Mathematical models are formulated and tracking algorithm is evolved. A combined PV system simulation model is developed in the SIMULINK. For a given solar insolation, the tracking algorithm changes the duty ratio of the converter such that the solar cell array (SCA) voltage equals the voltage corresponding to the MP point. This is done by the tracking algorithm, which mainly computes the power proportional to square of terminal voltage and changes the duty ratio of the converter so that this power is maximum. The proposed algorithm is implemented in real-time with the help of Analog Device ADMC-401 DSP evaluation module. The tracking program is developed to perform experimental investigations using analog-to-digital converter (ADC) interrupt. Using this processor we are able to track the MP within 200 ms. The proposed peak power tracking effectiveness is demonstrated through simulation and experimental results.     

基于CNN 与BiLSTM 的退化设备剩余使用寿命预测

针对DC-DC 变换器难以建立物理退化模型的问题,提出了一种基于卷积神经网络和双向长短期记忆 神经网络的剩余寿命预测算法。首先,通过对DC-DC 变换器中关键器件进行失效模式分析,得到DC-DC 变换 器的失效特征参数;然后,采用卷积神经网络对多传感器信号进行融合和特征提取,获得百分比指数退化指标; 其次,将获得的健康指标输入到融合注意力机制的双向记忆神经网络中,利用注意力机制对输出结果进行加权 融合,利用不同的权重值优化预测模型,最后,利用蒙特卡洛丢弃法获得剩余寿命的区间估计,并通过仿真数 据验证了所提出方法的有效性。     

Ultracapacitors + DC-DC converters in regenerative braking system

An ultracapacitor system for an electric vehicle has been implemented. The device allows higher accelerations and decelerations of the vehicle with minimal loss of energy and minimal degradation of the main battery pack. The system uses a DC-DC power converter, which is connected between the ultracapacitor and the main battery pack. The design has been optimized in weight and size, by using water-cooled heat sinks for the power converter, and an aluminum coil with air core for the smoothing inductance. The ratings of the ultracapacitor are: nominal voltage: 300 Vdc; nominal current: 200 Adc; capacitance: 20 Farads. The amount of energy stored allows us to have 40 kW of power during 20 seconds, which is enough to accelerate the vehicle without the help of the traction batteries. The vehicle uses a brushless DC motor with a nominal power of 32 kW and a peak power of 53 kW. A control system based on a Digital Signal Processor (DSP) manipulates all the aforementioned variables and controls the Pulse Width Modulation (PWM) switching pattern of the converter transistors. The car used for the implementation of this system is a Chevrolet LUV truck.     

超大功率电推进电源处理单元关键技术研究

针对深空探测等空间任务对超大功率(10kW~100kW范围)电推进系统的需求,通过对国内外超大功率电推进技术的调研,提出了一种50kW超大功率霍尔电推进系统电源处理单元（Power Processing Unit,PPU）设计方案,重点对核心的阳极电源关键技术进行研究,提出了四管Buck-Boost变换器和三相LLC谐振变换器级联的设计方案,为我国超大功率PPU的发展提供了技术参考。     

高频平面变压器技术研究

通过对平面变压器损耗分析及其不同绕组结构构造技术研究,采用多层交错换位绕组结构,设计了适用于有源箝位软开关变换器的PSSP结构平面变压器。将研制的平面变压器应用于100W高密度DC/DC模块,经实验验证,该变压器总损耗仅为1.3W,并且与传统的变压器比较,体积减小了46.6%,高度减小了68%。     

DC-to-DC Converter Power-Train Optimization for Maximum Efficiency

A new way is given to describe the independent and dependent design variables of the power train of a dc-to-dc converter in terms of a multidimensional design-parameter space. These concepts provide a framework for examining the problem of design optimization of the power train, with particular emphasis on the maximization of converter efficiency. Numerous examples of important parameterspace surfaces illustrate some of the major relationships between core volume, switching frequency, and output power and between efficiency, ripple, and temperature rise of the energy-storage reactor. Also, the difference in performance between the continuous and discontinuous magnetomotive (MMF) force modes of operation is explored.     

A new zero-voltage switching DC/DC boost converter

A pulsewidth-modulated (PWM) zero-voltage-switching quasi-resonant boost converter operating at constant switching frequency is presented. In contrast to the frequency-modulated (FM) zero-voltage-switching quasi-resonant boost converter, this converter possesses better controllability and higher operating performance, and overcomes the instability caused by the parasitic oscillation. The principle of operation and performance of the converter are presented. Its two-dimensional state trajectories and steady-state characteristic curves are derived which are useful for the converter design. Both the SPICE simulation and experimental result agree with the theoretical prediction     

Comments, with reply, on `Parallel resonant converter with LLC-typecommutation'

In a recent paper by C.Q. Lee et al. (ibid., vol.25, no.6, p. 844-7, Nov. 1989), the authors analyzed a DC-DC converter that they termed the LLC-type PRC (parallel resonant converter). Its resonant network contains three active components-two inductances and a parallel capacitance-and as a consequence the converter might be expected to have third-order dynamics. But Lee et al. employed a matrix transformation to show that the behavior of the circuit may be represented as a state-plane trajectory, as for a second-order circuit. The purpose of this contribution is to show that the converter has a zero-frequency eigenvalue, associated with undesirable circulating DC. The second-order dynamics exhibited by the third-order converter are explained by an application of Thevenin's theorem. Some aerospace applications of the LLC-type parallel resonant converter (PRC) are discussed. In their reply, the authors show that the circulating direct current does not exist in the practical converter circuit     

民用飞机防火系统试验室气流模拟系统设计

在民用飞机防火系统地面模拟试验中,由于气流流量对试验具有重要的影响,因此,需要模拟发动机风扇舱、发动机核心舱、APU舱和货舱在飞行中的气流流量。由于流量的精度对试验结果具有重要的影响,设计一种基于PLC控制的气流模拟系统,基于PID控制算法,通过变频器控制电机带动风机模拟所需的气流,满足地面试验的要求。     

Control design and closed-loop analysis of a switched-capacitorDC-to-DC converter

The theoretical and practical details involved in the control design and closed-loop analysis of a step-down switched-capacitor (SC) DC-to-DC converter are presented. The state-space averaging technique is applied to extract the small-signal dynamics of the power stage, and a graphical loop gain method is used to design the feedback compensation and analyze the closed-loop performance of an SC converter. The results of the control design and closed-loop analysis are substantiated by experiments using a prototype SC converter     

The Feasibility of Packaging High-Frequency Microcircuits Inside the Magnetic Core

A design goal for miniaturization has long been the elimination of the magnetic circuit. In practice, the size/weight penalties are decreased by operation at higher frequency where core size can be effectively reduced. When microcircuitry is considered, the magnetic circuit is designed out. Either RC or active networks replace inductance, or it is externally added to the microcircuit. This paper will demonstrate that the microcircuit elements can be readily interconnected inside of ferrite pot cores. Linear circuits using the magnetic circuit to advantage can be packaged in the same volume as the transformer, inductance, or filter alone. The natural RFI and radiation shielding, as well as heat transfer capabilities, are inherent with this form of packaging. For illustration, a 2-kV, 20-?A power supply featuring a 60-kHz, class C oscillator; a 10-volt, 100-mA converter featuring a 300-kHz square-wave oscillator; and a 9.5-volt, 100-mA switching regulator are packaged inside ferrite pot cores. With this technique only functional input-output connections are necessary, since the microcircuitry interconnections are inside the pot core.     

Voltage-based maximum power point tracking control of PV system

Photovoltaic (PV) generators exhibit nonlinear v-i characteristics and maximum power (MP) points that vary with solar insulation. An intermediate converter can therefore increase efficiency by matching the PV system to the load and by operating the solar cell arrays (SCAs) at their maximum power point. An MP point tracking algorithm is developed using only SCA voltage information thus leading to current sensorless tracking control. The inadequacy of a boost converter for array voltage based MP point control is experimentally verified and an improved converter system is proposed. The proposed converter system results in low ripple content, which improves the array performance and hence a lower value of capacitance is sufficient on the solar array side. Simplified mathematical expressions for a PV source are derived. A signal flow graph is employed for modeling the converter system. Current sensorless peak power tracking effectiveness is demonstrated through simulation results. Experimental results are presented to validate the proposed method     

Analysis and design of (LC)(LC)-type series-parallel resonantconverter

A series-parallel resonant converter employing (LC)(LC)-type tank circuit operating in lagging power factor (PF) mode is presented and analyzed using complex ac circuit analysis. Design curves are obtained and the converter is optimized under certain constraints. Detailed Space Integrated Control Experiment (SPICE) simulation results are presented to evaluate the performance of the designed converter under varying load conditions. Results obtained from an experimental converter are also presented. The results obtained from the theory, SPICE simulation, and the experimental converter are compared. The proposed converter has high efficiency from full load to very light load (<10%). Switching frequency variation required for a wide change in the load (near load open circuit to full load) is narrow compared with the series resonant converter (SRC)     

Start-Up Transient of a DC-to-DC Converter Powered by a Current-Limited Source

An analysis technique is presented which permits the designer to explore the start-up transient of a dc-to-dc converter when it is powered by a current-limited source. The current versus voltage characteristics of the source are superimposed upon those of the dc-to-dc converter. By noting the nature of the intersection of these curves in the voltage-current plane, we are able to predict whether or not the converter is able to start up while powering a specified load.     

Harmonic analysis of a parallel-loaded resonant converter

A method for calculating the harmonic components of the currents and voltages in a parallel-loaded resonant converter using frequency-domain techniques is presented. The converter is divided into an inverter section and a rectifier section. A harmonic model is developed for the resonant converter in which the rectifier section is treated as a voltage-dependent current sink. All voltages and currents in this model are represented by a Fourier series. The unknown coefficients in all Fourier series are calculated by using the harmonic model and Kirchhoff's laws. Because of the nonlinear nature of the rectifier section, an iterative technique must be utilized to find the unknown Fourier coefficients     

A fixed frequency LCL-Type series resonant converter

A fixed frequency LCL-type series resonant converter (SRC) which uses an inductive output filter is proposed. Steady-state analysis of the converter is presented using complex ac circuit analysis. Based on the analysis, a simple design procedure is given. Detailed space integrated control experiment (SPICE) simulation results are presented to evaluate the performance of the designed converter under varying load and supply voltage conditions. Also, detailed experimental results obtained from a metal-oxide-semiconductor field-effect transistor (MOSFET) based 500 W converter are presented to verify the analysis and SPICE simulation results. The results obtained from the analysis, SPICE simulation and the experimental converter are compared. The proposed converter requires a narrow variation in pulsewidth while maintaining lagging power factor mode of operation for a very wide variation in the load as well as supply voltage     

Fault-tolerance wide voltage conversion gain DC/DC converter for more electric aircraft

In this paper, a fault-tolerance wide voltage conversion gain DC/DC converter for More Electric Aircraft (MEA) is proposed. The proposed converter consists of a basic Cuk converter module and n expandable units. By adjusting the operation state of the expandable units, the voltage conversion gain of the proposed converter could be regulated, which makes it available for wide voltage conversion applications. Especially, since mutual redundancy can be realized between the basic Cuk converter module and the expandable units, the converter can continuously work when an unpredictable fault occurs to the fault-tolerant parts of the proposed converter, which reflects the fault tolerance of the converter and significantly improves the reliability of the system. Moreover, the advantages of small input current ripple, automatic current sharing and low voltage stress are also integrated in this converter. The working principle and features of the proposed converter are mainly introduced, and an experimental prototype with 800 W output power has been manufactured to verify the practicability and availability of the proposed converter.     

Analysis and design of a three-phase LCC-type resonant converter

A three-phase dc-to-dc LCC-type resonant converter with high-frequency transformer isolation is proposed. The operation and a simple analysis of the converter are presented. Design curves are obtained and a design example is given. SPICE simulation and experimental results are presented to verify the performance of the proposed converter for varying load conditions. The converter proposed has several advantages, e.g., operation in lagging PF mode for the entire load range, requires a narrow variation required in switching frequency, reduced component size and stresses, etc