Text B DC翻译.docx

Text B DC-DC converter application 电源转换器的应用程序DC Motor Drive 直流电机驱动 Before the widespread application of power-electronic drives to control AC machines, DC motors were by far the machines of choice in applications requiring flexibility of control. Although in recent AC drives have become quite common, the ease of control of DC machines insures their continued use in many applications. 在电力电子驱动控制交流电机得到广泛应用之前,直流电机是目前要求机器应用程序控制灵活的（普遍）选择。尽管最近AC驱动器已经变得普遍,但易于控制的直流机确保它们能继续在许多应用程序中使用。Based on characteristics of DC motor, a power electronic converter supplying a DC should have the capabilities: 基于直流电机的特点,电力电子变换器提供一个直流（电机）应具备的动力:(1),The converter should make its output voltage and current to reverse in order to yield a Four-quadrant operation. (1),变频器应使其输出电压和电流反向,以用来能在四个象限来运行。(2),The converter should be able to operate in a current-controlled mode by holding the current at its maximum acceptable value during fast acceleration and deceleration. The dynamic current limit is generally several times higher than the continuous steady-state current rating of the motor. (2)转换器应该在其最大可接受的值快速加速和减速，以确保在当前能够运行在电流控制模式。动态电流限制通常是高于连续稳态电动机的额定电流几倍（数值）。(3),For accurate control of position, the average voltage output of the converter should vary linearly with its control input, independent of the load on the motor. (3),为了能进行位置的精确控制,平均电压转换器线性控制的输出应该与其控制的输入成线性关系,且独立于电机上的负载。(4),The converter should produce an armature current with a good form factor and should Minimize the fluctuations in torque and speed of the motor. (4)转换器应该用一个很好的形式因素产生一个电枢电流和减小电机的转矩和速度的波动。(5),The converter output should respond as quickly as possible to its control , thus allowing the converter to be represented essentially by a constant gain without a dead time in the overall servo drive transfer function model. (5)转换器输出应该尽可能快回应它的控制,从而使转换器基本上在整个伺服驱动传递函数模型中有固定时间的恒定增益Switch-mode DC-DC converters may satisfy all the requirements listed above. A full-bridge switch-mode DC-DC converter produces a four-quadrant controllable DC output The overall system is shown in Fig.3.11, where the line-frequency AC input rectified into DC by means of a dioderectifier of the type and filtered by means of filter capacitor . An energy dissipation circuit is included to prevent the filer capacitor voltage from becoming large in case of braking of the DC motor. 开关型直流-直流转换器可以满足上面列出的所有要求。一个全桥开关型直流-直流转换器产生一个四方形的可控直流如图Fig.3.11所示,整个系统输出线频率的交流电输入整流成直流通过类型的二极管整流器和过滤通过滤波电容器。能量耗散电路包括防止编档人员电容器电压成为大型直流电机的制动。All four switches in the converter of Fig.3.11 are switched during each cycle of the switching frequency. This results in a true four-quadrant operation with a continuous current conduction, where both Ut and Ia can smoothly reverse, Independent of each other. Ignoring the effect of blanking time ,the average voltage output of the converter varies linearly with the input control voltage ucontrol independent of the load: 所有四个开关变换器的Fig.3.11切换在每个周期的开关频率。这导致一个真正的四象限运行连续电流传导,Ut和Ia都可以顺利逆转,相互独立的。忽略消隐时间的影响,平均电压转换器的输出与输入控制电压线性变化ucontrol独立负载:Ut=kc*ucontrol Ut = kc * ucontrolwhere kc is the gain of the converter. kc是转换器的增益。Switching DC Power Supplies 开关直流电源Regulated DC power supplies are need for most analog and digital electronic systems. Most power supplies are designed to meet some or all of the following requirements: 直流稳压电源是最需要的模拟和数字电子系统。大多数电力供应是为了满足一些或所有下列条件:Regulated output. The output voltage must be held constant within a specified tolerance for changes within a specified range in the input voltage and the output loading. 调节输出。输出电压必须保持不变在指定公差的变化在一个指定范围的输入电压和输出负载。隔离。输出可能需要从输入电绝缘。Isolation. The output may be required to be electrically isolated from the input. Multiple outputs. There may be multiple outputs (positive and negative) that may differ in their in their voltage and current ratings. Such outputs may be isolated from each other. 多个输出。可能会有多个输出(积极的和消极的),可能有不同的电压和电流等级。这样的输出可能是彼此孤立的。In addition to these requirements, common goals are to reduce power supply size and weight and improve their efficiency. Traditionally ,linear power supplies. The cost comparison between linear and switching supplies depends on the power rating. 除了这些需求,共同的目标是减少电源尺寸和重量、提高效率。传统的线性电源。线性和开关之间的成本比较供应依赖于额定功率。As opposed to linear power supplies, in switching power supplies, the transformation of DC voltage from one level to another is accomplished by using DC-to-DC converter circuits (or those derived from them). These circuits employ solid-state devices ( transistors, MOSFETs, etc ), which operate as a switch: either completely on. Since the power devices are not required to operate in their active region, this mode of operation results in the lower power dissipation. Increased switching speeds, higher voltage and current ratings, and a relatively lower cost of these devices are the factors that have contributed to the emergence of switching power supplies. 与线性电源、开关电源、直流电压的转换从一个水平到另一个是通过使用DC-to-DC转换器电路(或那些由它们驱动的)。这些电路采用固态器件(晶体管、场效应管等),作为一个开关:要么完全。自从电力设备不需要在他们的活跃区,这种模式的操作会导致更低的功耗。提高开关速度,更高的电压和电流等级,和相对低成本的这些设备的因素促成了开关电源的出现。Fig.3.22 shows a switching supply with electrical isolation in a simplified block diagram form. The input AC voltage is rectified into unregulated DC voltage by means of a diode rectifier of the type. It should be noted that an EMI filter is used at the input to prevent the conducted EMI. The DC-DC converter block in Fig.3.12 converts the input DC voltage from one level to another DC level. This is accomplished by high frequency switching , which produces high frequency AC across the isolation transformer. The secondary output of the transformer is rectified and filtered to produce U0. The output of the DC supply in Fig.3.12 is regulated by means of feedback control that employ a PWM controller, where the control voltage is compared with a sawtooth waveform at the switching frequency. The electrical isolation in the feedback loop is provided either through an isolation transformer as shown or through an optocoupler. Fig.3.22显示了开关电源在电隔离在一个简化的方框图的形式。输入交流电压整流成不受监管的直流电压通过一个二极管整流器的类型。应该注意的是,使用一个EMI滤波器的输入防止EMI进行。直流-直流转换器块在Fig.3.12转换输入直流电压从一个水平到另一个直流的水平。这是通过高频开关,隔离变压器产生高频交流电。二次输出变压器的纠正和生产半线性过滤。Fig.3.12直流供电的输出是由反馈控制的方法,采用PWM控制器,控制电压的开关频率与锯齿波形。的电气隔离反馈回路提供了通过一个隔离变压器或光耦合器。In many applications, multiple outputs ( both positive and negative) are required. These outputs may be required to electrically isolated from each other ,depending on the application. 在许多应用程序中,多个输出(正面和负面)是必需的。这些输出可能需要取决于应用程序。通过电平控制使之相互隔离。Two major advantages of switching power supplies over linear power supplies are now apparent. These are as follows: 开关电源的两个主要优势在线性电源现在明显。这些都是如下:The switching elements (power transistors or MOSFETs) operate as a switch: either completely off completely on. By avoiding their operation in their active region ,a significant reduction in power losses is achieved . This results in the higher energy efficiency in a 70%90% range. Moreover, a transistor opera