DCDC级联变换电路设计与实现英文文献和翻译.doc

DC - DC converter (DC / DC) converter is widely used in remote and data communications, computer, office automation equipment, industrial instrumentation, military, aerospace and other fields related to the national economy all walks of life.Divided by the size of the rated power, the DC / DC can be divided into 750W, 750W 1W and 1W to the following three categories. In the 1990s, the growth rate of the DC / DC converter in low power range greatly improved, 6W of 25WDC/DC converter growth rate, this is because they are used extensively for DC measurement and test equipment, computer display systems, computers and military communications systems.By the low-power high-speed microprocessors, DC / DC converter to the direction of the power development is an inevitable trend, so the faster growth rate of 251W 750W DC / DC converter, which it is used services of medical and laboratory equipment, industrial control equipment, telecommunications equipment, multi-channel communication and transmission equipment, DC / DC converter in the field of remote and digital communications has broad application prospects. DC / DC converter will transform a fixed DC voltage to a variable DC voltage, this technique is widely used in the trolley bus, subway, trains, electric cars continuously variable transmission and control, while making the above control has accelerated stable respond quickly to performance, and at the same time receive the effect of saving energy. DC chopper instead of the rheostat savings 20% to 30% of the energy. DC chopper can not only play the role of the regulator (SMPS), can also play a role effectively suppress the noise of the grid side harmonic current. DC / DC converter has been commercialized, the module uses high-frequency PWM technology, the switching frequency is about 500kHz, the power density of 0.31W/cm3 1.22W/cm3. With the development of the LSI, the power supply module to achieve the miniaturization is necessary to continuously improve the switching frequency and a new circuit topology. At present, some companies have already developed and produced the second zero-current switching and zero voltage switching power supply module, power density has dramatically increased.The rapid development of the electronics industry has greatly promoted the development of the switching power supply. The high-frequency switching power supply miniaturization technology has become the mainstream of modern electronic devices, power supply system. In the field of electronic devices, usually to rectifier called a power DC / DC converter will be called the secondary power supply. Once the role of the power supply is single or three phase AC mains to transform a nominal 48V DC power supply. In power electronic devices using a traditional phased power supply has been replaced by high-frequency switching power supply, high frequency switching power supply (also known as the switch type Rectifier SMR) MOSFET or IGBT high frequency work. The switching frequency is generally controlled within the range of 50kHz 100kHz, high efficiency and miniaturization. In recent years, the switching regulator power capacity continues to expand, stand-alone capacity has been expanded to from 48V/12.5A, 48V/20A 48V/200A, 48V/400A. A wide range of electronic equipment used in the IC power supply voltage varies, the electronic power supply system, the use of high frequency high power density DC / DC isolated power supply module from the intermediate bus voltage (typically 48V DC ) transform into a variety of DC voltage, can greatly reduce the wear and tear, easy maintenance, installation and compatibilizer is very convenient. General can be directly installed in the standard control panel, the requirements of the secondary power supply is a high power density. Because of the growing capacity of electronic devices, power capacity will continue to increase. DC / DC switching power supply for its high efficiency, high integration features in portable electronic products in a wide range of applications. With the development of integrated circuit technology, the structure is complex, but the better performance of the peak current the mode PWMDC / DC switching power converters has become the market mainstream. Classification and direction of development of switch mode power supplies The switch mode power supplies is the use of modern power electronics technology, to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply. Switch mode power supplies can be divided into the AC / AC power supply, DC / DC power supply, AC / DC power supply and DC / AC power supply, the most widely used DC / DC switching power supply. DC / DC switching power supply is divided into inductive switching power supplies and capacitor switching power supply. A. Inductive switching power supply Inductive switching power supply inductance as the main energy storage components to provide a continuous current to the load can be done through the different topologies of buck, boost, and negative pressure function. Inductive switching power supply with very high conversion efficiency, the energy loss of its work include: 1) internal or external MOSFET conduction losses, mainly with the duty cycle of MOSFET on-resistance; 2) dynamic loss including the power MOSFET turns on the switching losses and drive MOSFET switched-capacitor power loss with the input voltage and switching frequency; 31 static loss, with Ic internal leakage current. The load current is large, the above losses are relatively small, so the inductive switching power supply can reach 95% efficiency. These losses will be relatively larger affect the conversion efficiency decreases, but the load. The drawback of the inductive switching power supply power program as a whole larger (mainly inductors and capacitors), the output voltage ripple in the PCB layout to be extra careful to avoid the If the EM (Electro Magnetic Interference). Increase the switching frequency can effectively reduce the size of inductors and capacitors and output voltage ripple. B. Capacitive switching power supply - the charge pump The charge pump is to use capacitors as energy storage components. The internal switch control charge and discharge of the capacitor array. In order to reduce EMI and ripple due to switching, many design uses a dual charge pump structure. The charge pump boost, buck, and negative pressure function can be completed. Because of the charge pump circuit structure within reason, when the output voltage and input voltage into a certain multiple of the relationship, such as 2 times or 1.5 times the maximum efficiency of up to 90%. But the efficiency will vary with the ratio between the two will be as low as 70%, should make use of the charge pump is the best conversion working conditions. Due to the limitations of the storage capacitor, the output voltage is generally no more than three times the input voltage, output current does not exceed 300mA. The charge pump characteristics between LDOs (10wdropout the regulator) and inductive switching power supply with high efficiency and relatively simple peripheral circuit design, EMI and ripple center, but the output voltage and output current limit. The switched-mode power supplies, known as energy efficient power supply, it represents the direction of development of the power supply, DC / DC power supply has become a mainstream product. The worlds leading leading semiconductor companies have increased investment in performance power management integrated circuit design and launch new products. In recent years, the switched-mode power supplies, the rapid development towards the higher level of integration, improve efficiency, improve control accuracy, and small lightweight. 1. Higher level of integration. Early switching converter power supply system to the discrete components. 1990s, the late emergence of the PowerIC by the control chip, the power switch and inductor-capacitor components. Easily achieve a significant reduction in power conditioning, remote control functions, as well as size, weight, power integrated circuits conform to modern portable electronic devices demand for electricity, and therefore has been widely used and rapid development. Integrated switching power supply in the communications industry, industrial automation, automotive manufacturing, aerospace technology and other fields to become the mainstream of the power supply design, represents the direction of development of power supply, known as energy-efficient power. Development today, the power IC controller chip control circuit and power switch integrated with, only a small amount of external inductance, capacitance components can easily constitute a switching power supply. Can be expected with the inductor integrated on the chip technology is maturing, the integration of switching power supply system will be higher. 2. To improve power conversion efficiency. Improve power conversion efficiency means lower power consumption. The switching losses of the switching converter include: 1) switching device turns on, current flows through the switch on-resistance, resulting in conduction losses; 2) switching devices in the conduction cut-off between the conversion, the gate-source switch capacitor charging and discharging due to switching losses. Aimed at reducing these two losses, the development of synchronous rectification and soft switching technology. Synchronous rectification MOSFET in place of a rectifier diode, the MOSFET on-resistance is very low, only a few dozen Q-chat, the conduction losses of the rectifier element is greatly reduced, to improve the conversion efficiency. Synchronous rectification technology is particularly suitable for application in low voltage, high current situations. Switch topologies in PWM (Pulse.Width Modulation): the power switch turns on, the moment of shutdown, the use of auxiliary switch caused by the main switch zero voltage or zero current turn on or off in the non-switching time circuit PWM method is still work Therefore, the main circuit voltage, current amplitude remains the same as the conventional PWM converter. Another advantage of this technology is its zero-voltage zero-current switching conditions from the input voltage and load changes.Characteristics of the voltage waveform overlap, so that the switching loss is approximately zero, the current transformation process, thereby enhancing the power conversion efficiency of the system. The soft-switching technology for high switching frequency applications. In addition, low-power standby, remote shutdown, light load automatically reduce the switching frequency and other measures to improve the conversion efficiency. 3. Improve control accuracy. Switching converter control the development of the voltage and current dual-loop feedback control, which based on the average current control PWM control technology to achieve precise control of the average inductor current, has been successfully used in power factor from the initial voltage single-loop feedback control correction circuit. In addition, the charge control technology. 4. Small lightweight. Switching power supply is smaller and smaller. With the improved integration of external components, switching power supply needed is less and less: With the improvement of the switching frequency, the system inductance, capacitance component values decrease, inductance, capacitance element occupied by the volume decrease. In addition, the topology of multi-channel power output by the same input power. Multi-output power supply can be parallel or serial. Single-input multi-output DC / DC converter can be effective in reducing the whole volume is to achieve machine performance optimization measures. Generally speaking, the current switching converter development of technology trends: high-frequency technology, the soft-switching technology, the PFC (Power Factor Correction) technology, modular technology, and low output voltage technology. 直流-直流变换器(DC/DC)变换器广泛应用于远程及数据通讯、计算机、办公自动化设备、工业仪器仪表、军事、航天等领域，涉及到国民经济的各行各业。按额定功率的大小来划分，DC/DC可分为750W以上、750W1W和1W以下3大类。进入20世纪90年代，DC/DC变换器在低功率范围内的增长率大幅度提高，其中6W25WDC/DC变换器的增长率最高，这是因为它们大量用于直流测量和测试设备、计算机显示系统、计算机和军事通讯系统。由于微处理器的高速化，DC/DC变换器由低功率向中功率方向发展是必然的趋势，所以251W750W的DC/DC变换器的增长率也是较快的，这主要是它用于服务性的医疗和实验设备、工业控制设备、远程通讯设备、多路通信及发送设备，DC/DC变换器在远程和数字通讯领域有着广阔的应用前景。 DC/DC变换器将一个固定的直流电压变换为可变的直流电压，这种技术被广泛应用于无轨电车、地铁、列车、电动车的无级变速和控制，同时使上述控制具有加速平稳、快速响应的性能，并同时收到节约电能的效果。用直流斩波器代替变阻器可节约2030的电能。直流斩波器不仅能起到调压的作用(开关电源),同时还能起到有效抑制电网侧谐波电流噪声的作用。 DC/DC变换器现已商品化，模块采用高频PWM技术，开关频率在500kHz左右，功率密度为0.31W/cm31.22W/cm3。随着大规模集成电路的发展，要求电源模块实现小型化，因此就要不断提高开关频率和采用新的电路拓扑结构。目前，已有一些公司研制生产了采用零电流开关和零电压开关技术的二次电源模块，功率密度有较大幅度的提高。电子产业的迅速发展极大地推动了开关电源的发展。高频小型化的开关电源及其技术已成为现代电子设备供电系统的主流。在电子设备领域中，通常将整流器称为一次电源，而将DC/DC变换器称为二次电源。一次电源的作用是将单相或三相交流电网变换成标称值为48V的直流电源。目前，在电子设备中用的一次电源中，传统的相控式稳压电源己被高频开关电源取代，高频开关电源(也称为开关型整流器SMR)通过MOSFET或IGBT实现高频工作，开关频率一般控制在50kHz100kHz范围内，实现高效率和小型化。近几年，开关整流器的功率容量不断扩大，单机容量己从48V/12.5A、48V/20A扩大到48V/200A、48V/400A。 因为电子设备中所用的集成电路的种类繁多，其电源电压也各不相同，在电子供电系统中，采用高功率密度的高频DC/DC隔离电源模块，从中间母线电压(一般为48V直流)变换成所需的各种直流电压，可以大大减小损耗、方便维护，且安装和增容非常方便。一般都可直接装在标准控制板上，对二次电源的要求是高功率密度。因为电子设备容量的不断增加，其电源容量也将不断增加。 DCDC开关电源以其高效率、集成度高的特点在便携式电子产品中得到了广泛的应用。随着集成电路技术的发展，结构复杂但性能更好的峰值电流模式PWMDCDC开关电源变换器已经成为市场的主流。 开关式电源的分类及发展方向 开关式电源是利用现代电力电子技术，控制开关晶体管开通和关断的时间比率，维持稳定输出电压的一种电源。开关式电源可分为ACAC电源、DCDC电源、ACDC电源和DCAC电源，应用最广泛的就是DCDC开关式电源。DCDC开关式电源分为电感式开关电源和电容式开关电源。 1电感式开关电源 电感式开关电源是利用电感作为主要的储能组件，为负载提供持续不断的电流，通过不同的拓扑结构可以完成降压、升压和负压的功能。电感式开关电源具有非常高的转换效率，其工作时主要的电能损耗包括：1)内置或外置MOSFET的导通损耗，主要与占空比和MOSFET的导通电阻有关；2)动态损耗，包括功率MOSFET同时导通时的开关损耗和驱动MOSFET开关电容的电能损耗，主要与输入电压和开关频率有关；31静态损耗，主要与Ic内部的漏电流有关。 在负载电流较大时，上面的损耗都相对较小，故电感式开关电源可以达到95的效率。但是在负载变小时，这些损耗就会相对变大而影响转换效率。电感式开关电源的缺点是电源方案的整体面积较大(主要是电感和电容)，输出电压的纹波较大，在PCB布板时必须格外小心以避免EM If ( Electro Magnetic Interference)。提高开关频率可以有效的减小电感和电容的体积及输出电压纹波。 2电容式开关电源电荷泵 电荷泵是利用电容作为储能组件内部的开关管数组控制电容的充放电。为减少由于开关造成的EMI和纹波，很多设计采用双电荷