变换器

The converter can be improved just by exchanging the position of the resonant inductance and the transformer such that the transformer is connected with the lagging leg. The improved converter has several advantages over its counterpart, e.g., the clamping diodes conduct only once in a switching period, and the resonant inductance current is smaller in zero state, leading to a higher efficiency and reduced duty cycle loss. The operation principle of the improved converter and the comparison with the original converter are analyzed in this paper. The effect of the blocking capacitor in series with the transformer or resonant inductance is discussed, and a best scheme is determined.The improved converter is adopted to design the DC/DC converter of secondary power supply in HVDC power system.

本文将谐振电感和变压器交换位置，使变压器与滞后桥臂相连，这样箝位二极管在一个开关周期中只导通一次，同时零状态时谐振电感电流较小，有利于提高变换效率和减小占空比丢失，本文分析改进后变换器的工作原理，并与改进前的变换器进行对比，讨论隔直电容在不同位置对变换器工作的影响，确定一种最佳工程方案。

In this article two functional modes of the Fly-back Converter (Continuous Conduct Mode and Discontinuous Conduct Mode) are particularly analyzed, which include their characteristics, applications, the critical pattern of two functional modes is argued, both the exact boundary from the angle of circuit parameters is crystallized, at the same time, basic principle of PFC under the DCM mode is introduced, which settle theoretical basis for the subsequent design; by establishing the mathematic model of the converter, a further investigation of the configuration is made, qualitatively and quantitatively, analyzed to settle exactly theoretical basis for the subsequent emulation and the experimental parameter; from the angle of steady-state analysis, the transfer function of the system is deduced to establish dynamic small-signal state equation, emulating the system with the help of matlab, then according to the simulation result and the theory of PFC revise the system, lastly, we adopt the project which add a zero-pole compensator to the voltage loop, by this way, a satisfied system performance is gained and the PFC scheme is ensured successfully; finally, based on the previously-done work, we combining with the situation of specific design requirement, acquired the numerical value of each unit devices in this converter

详细分析了反激式变换器的两种工作状态，连续模式(Continuous Conduct Mode ，简称CCM)和断续模式(Discontinuous Conduct Mode，简称DCM)以及各自的特点、应用场合，论证了两种工作状态的临界模式，从电路参数的角度明确了二者的界限，同时还介绍了DCM模式下PFC的基本原理，为后面的设计奠定理论基础；通过对整个变换器系统建立准确的数学模型，对此变换器的电路结构做了进一步的研究，定性、定量地分析了变换器各部分的工作状态，为仿真和实验参数的确定以及电路参数的优化提供理论依据；从稳态分析的角度，为系统建立了动态小信号状态方程并推导出系统的传递函数，利用matlab对系统进行仿真，进而根据仿真结果以及PFC的相关理论对系统进行校正，采用在电压环加入零点—极点补偿器的设计方案，得到了满意的系统特性并且保证了PFC的顺利实现；最后，在前面所做工作的基础上，结合设计要求计算出此变换器系统中每个元器件的数值，利用Pspice对其进行了仿真、优化，然后根据仿真结果搭建了硬件电路。

Due to the high reliability, high stability and low EMI criterions in auxiliary power supply systems, the half-bridge LLC resonant converter is selected for the front-end converter, the AC bus architecture and full-wave rectifier are as well utilized. The turns-ratio between the AC bus and load converter is 1:1. The effect of beads which are used in the load converters to the resonant circuit is analyzed.

根据辅助电源高可靠性、高稳定性、低电磁干扰、良好的高频隔离的要求，通过对不同拓扑类型的分析比较，选择半桥LLC谐振变换器作为前级变换器，交流母线和零式全波整流结构作为后级变换器，在母线和后级变换器的连接上采用1∶1的隔离变压器连接。

In order to assist Boost converter design, the working process of the converter at discontinuous current mode was analyzed and a nonlinear mathematical model was estabilished as well. Case study on Matlab/ Simulink was performed with binary logical variable used, the simulation result was consistent with the theoretical analysis which proveed the validitd and feasibility of the proposed model. The model could be used to assist Boost circuit design effectively and supplie a basis for parameter optimization.

为了辅助升压变换器在应用中的设计，分析了电流断续状态下Boost变换器的工作过程，建立了这种状态下的Boost变换器非线性数学模型，在结合二进制逻辑变量，建立了Simulink模块下的变换器仿真模型，研究表明仿真结果与理论分析结果一致，证实了模型的准确性和可行性，这种逻辑与模拟结合的简明通用的模型可以高效辅助Boost电路设计并为参数优选打下了基础。

In order to realize real-time control, the paper studied two kinds of closed-loop control structures such as based on scalar quantity and double closed-loop control structure, moreover established their control structure, then simulation to the double closed-loop control structure of voltage source type matrix converter. The simulation results indicate that reach the real-time control requests, the system dynamic response performance is good, the converter input output can be adjusted in the short time.

为实现电压源型阵变换器的实时控制要求，论文对基于标量控制和双闭环的两种电压源型矩阵变换器闭环控制结构进行了研究，分别建立了这两种闭环控制的控制结构，并且对电压源型矩阵变换器的双闭环控制结构进行仿真，仿真结果表明达到了实时控制的要求，系统的动态响应性能好，变换器的输入输出能在较短的时间内达到调节。

The First Law of thermodynamics and exergy analysis method were used to construct factors such as coefficient of performance , exergy efficiency and exergy index according to the AHT combined Carnot cycle model established. Aimed at the insufficient of the classical thermodynamics analysis method, the optimization relationships between the specific heating load and operating parameters, and between SHL and COP, was reasoned out using the Finite Time Thermodynamics method according to the characteristic of investment and capacity of AHT, and endo-reversible combined Carnot cycle model. Hence, the rationality of the energy utilization and the economic index, which related to the total heat transfer area, were both taken into account.

首先利用热力学第一定律分析法和〓分析方法，按照建立的吸收式热变换器理想联合卡诺模型，构建包括性能系数、热力学效率、〓效率、〓指数在内的吸收式热变换器热力学评价体系；然后针对经典热力学分析方法的不足，根据热变换器的功能、投资等方面的特点，按照内可逆联合卡诺模型，利用有限时间热力学理论方法，导出了吸收式热变换器比供热率与操作参数、比供热率与热力学性能系数的优化关系，从而使优化结果兼顾了系统用能的合理性和与总传热面积相关的反映设备投资回报的经济性指标。

With the development of semiconductor devices, the switching frequency of PWM converters becomes higher, which makes PWM converters (mainly high-frequency transformers, inductors and capacitors in converters) smaller, and this will benefit design and application of them. Whats more, higher switching frequency will reduce the audio-frequency noise and improve dynamic response of PWM converters.

随着半导体器件技术的不断发展，PWM变换器所能达到的开关工作频率越来越高，使得变换器(主要是变换器中的高频变压器、电感等磁性元件和电容)的体积和重量越来越小，这有利于PWM变换器的设计及推广应用。

A novel hybrid diode-clamp cascade multilevel converter is presented in this paper. The new concept of the converter is based on connection of multiple diode-clamp converter modules with different dc bus voltages. Normally, the voltage blocking capability of faster devices such as IGBT and the switching speed of high voltage devices like GTO are found to be limited.

该文在研究传统的级联多电平、传统混合级联多电平以及二级管钳位级联多电平变换器的基础上提出了一种新型的混合二极管钳位级联多电平变换器，这种新型变换器是将具有不同直流母线电压的多个二极管钳位多电平变换器进行级联，输出电压是将这些变换器的输出电压进行矢量相加而合成的。

The characteristics analysis of two different current -to-voltage convertors,current transformer an reactance transformer ,shows that the current transformer has the same converting effect on the currents with different frequencies,while the reactance transformer transforms has various converting effect.

通过对电流互感器式&电流-电压&变换器和电抗变压器式&电流-电压&变换器变换特性的分析，结果表明：对于不同频率的电流，电流互感器式&电流-电压&变换器对它们的变换几乎是相同的。

This circuit can be widely used in other topology, such as flyback converter, half bridge converter, full bridge converter and push-pull converter with synchronous rectifier.

这个电路可以推广到其他隔离变换器的拓扑中，如反激变换器同步整流、半桥变换器同步整流、全桥变换器同步整流和推挽变换器同步整流。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。