磁感应电机软启动英文翻译.doc

磁感应电机软启动模糊操纵器的概念非常简单 。他们由输入界面，处理界面和输出界面构成 。输入界面如类似开关，对适当的状态和真实值等等的传感器或其他的输入模式。处理界面要求每个适当规则保护，产生的每个结果都是规则的结果，然后结合 。最终，输出界面转换合并所有的结果成为特定的控制输出值 。另外，阶梯形状和0曲线度被使用，尽管状态的最大共同的形状是三角形，但是形状一般地不那么比曲线度和他们的安排的数字重要。从37曲线度一般地为了用模糊的形式遮盖输入值或“全部数值”范围适当 。如同以前被讨论的那样处理界面，以如果、结束陈述的形式根据逻辑规则的模式在什么地方的部分被叫做“前例”并且，部分被叫做“必然的结果”。典型的模糊控制系统有许多的规则 。考虑恒温器的规则：（温度“冷”）、（加热器“高”）等如果这中规则作为一些“寒冷的”真实值的“温度”输入的真理值来在模糊的模式中作为一些“高度的”值 的“加热器”输出产生结果 。这中结果为了产生最初混成的输出用其他的规则的结果最终被使用。明显地更大真实的“寒冷”评价，虽然这未必是表示输出的本身，将从这被放到“高度”上，真实值在表中仅仅是1规则的更高的。在一些例子中状态相等的修改 。共同的包括“在附近”、“大致”、“微小地”、“非常”、“极端地”和“稍微”的。虽然这个定义能在不同的实现之间相对的变化，这些操作可以有明确的定义。例子1正方形的状态“非常”有效；真实值总是1以下，这把状态功能变窄 。“极端地”三字方时候“稍微”拿平方根放宽功能是为了形成非常窄的值。在实践中，模糊的规则的模式通常让几个被结合的前例使用，模糊操作员虽然定义再一次倾向于变化，并且，在1中的定义仅仅使用全部前例时候或评价最大的使用时最重要。从给予“互补的”功能的1另外有减去状态功能的“非”运算符。用推理方法输出的状态功能得到的真理值用定义规则，但是，最多1最简单的结果“最大最小限度”的不同的方法。规则能平行在硬件中或者按顺序软件中被解答。全部激发的规则的结果都给最初的值所定几个方法。理论上各种的优点和缺点每个里都有。质心法与规则非常的结合输出，另一方面高度方法明显地赐与规则最合适的输出值。柔性软启动器的作用是在电器的开始运行时减少电压使其运行，柔性软启动提供给电动机的主要方面是控制抵抗或电抗的危害。柔性软启动的控制电流是可调的，为控制电流的固定的装置，因而，产生的电压使用与电动机。在理论中，柔性软启动控制应用的每个电压，能与被控电动机的电压进行有效的成直线排列的连接，或者，在电机的内部进行连接。以实现其作用。这些固定的开关给出了一定的值，他们在每个部分的周期以相似的方法控制每个阶段。平均的电压通过改变开关的传导角度控制 ，增加传导角度将增加平均的输出电压 。以固定的开关控制有相当数量的平均输出电压和抵抗最初者有关的效率里，固定的控制开关能改变电压大小是主要的优点。典型的控制中，初始者电压是需要进行有效的抵御的，另一个固体的开关主要的优点是为了有适合的平均电压必须在电机启动开始能简单地被改变 。随着传导角度的变化，输出电压能被增加，或者减少，并且，还能利用电子学自动控制完成。控制电子学为了解决电机的启动根据计算时间的连续性（开环）特别设定电压高低的预订程序或者为了控制电流和速度（闭环）进行灵活的控制输出电压。转换的要素必须能控制到发动机在线路中被应用的电流 。为了用真正技术提供维持可信赖性高水平的设备，被确定为至少有3个转换的要素是必要计算时间的线路电压。在400伏提供上，这表示必要条件为1200伏装置和600 伏装置在200伏以上提供。另外，转换的要素有转瞬即逝的好处，现在的超载容量这很重要 。现在转瞬即逝的超载特点达到1200伏是不容易地，但可以利用，另外，选择在SCR-Diode和 SCR-SCR之间进行使用。这些操作有一些适当，但是，他们不是简单地能到达的。SCR-SCR和SCR-Diode任意选择之间的主要的差异是输出电压的价格和协调的内容。当SCR-Diode方法从技术角度模糊的时候，提供从技术角度合乎需要的左右对称的输出的SCR-SCR向控制干扰和噪声提供商业上更有效而且更容易实现。声学和偏执狂已经在今天市场上彻底地减少了，SCR-Diode型的柔软启动的数字还存在。技术不总是简单地如此，用类似的被用来和在描述 SCR-SCR系统的6脉冲技术相反描述SCR-Diode系统的3脉冲技术的词是可以识别的。闭环系统是监视来自开始的输出的特性或效果，把开始的电压从侧面灵活的得到回答。大部分的软启动器的闭环系统是在发电机在开始期间里监视电流，为了给以被控对象把设备的软启动器的电流以斜面的形式出现。更稀少的闭环系统加装了是监视发电机的速度和起点的加速度的A编码装置和控制发电机加速度或线性的比率，软启动器的控制是通过时间改变电流水平。在最基本的系统中的软启动中，软启动是实现控制对象与标准的数值进行比较以监视设备的运行状况，如果电流超过规定的点，那就显示错误，综合的闭环系统将监视全部的3个阶段上的电流，灵活的改变输出电压使之订正为合适的电流。这个系统能增加和减少，为了适合应用减少开始电压。电机的启动电流是软启动器交给发电机的，其电流将从0伏开始出发，讯速的增加到输出电压，于是，可以看出，任何一个完整的电压都被接触到调整发电机的输出电压和进行电动机的超载控制保护的操作。电动机的启动条件是保持必要的转矩是实现电机运行的理想条件，我们是有在一定的时间内的时期，在控制模式中，限制被加斜面上的电流和以前是一样的。从最开始的启动，限制电流和时间是通过可调的，为了合适的应用是事先设定的，现在的软启动技术有相当数量设备中应用，是机器使用的必要条件，担负输出的设备是这样与其他的如泵抽方式相类似的，是控制最初的转矩，由于其优越性，所以软启动技术被广泛采用。.Soft Starters for Induction MotorsFuzzy controllers are very simple conceptually. They consist of an input stage, a processing stage, and an output stage. The input stage maps sensor or other inputs, such as switches, thumbwheels, and so on, to the appropriate membership functions and truth values. The processing stage invokes each appropriate rule and generates a result for each, then combines the results of the rules. Finally, the output stage converts the combined result back into a specific control output value. The most common shape of membership functions is triangular, although trapezoids and bell curves are also used, but the shape is generally less important than the number of curves and their placement. From three to seven curves are generally appropriate to cover the required range of an input value, or the universe of discourse in fuzzy jargon. As discussed earlier, the processing stage is based on a collection of logic rules in the form of IF-THEN statements, where the IF part is called the antecedent and the THEN part is called the consequent. Typical fuzzy control systems have dozens of rules.Consider a rule for a thermostat: IF (temperature is cold) THEN (heater is high)This rule uses the truth value of the temperature input, which is some truth value of cold, to generate a result in the fuzzy set for the heater output, which is some value of high. This result is used with the results of other rules to finally generate the crisp composite output. Obviously, the greater the truth value of cold, the higher the truth value of high, though this does not necessarily mean that the output itself will be set to high, since this is only one rule among many. In some cases, the membership functions can be modified by hedges that are equivalent to adjectives. Common hedges include about, near, close to, approximately, very, slightly, too, extremely, and somewhat. These operations may have precise definitions, though the definitions can vary considerably between different implementations. Very, for one example, squares membership functions; since the membership values are always less than 1, this narrows the membership function. Extremely cubes the values to give greater narrowing, while somewhat broadens the function by taking the square root. In practice, the fuzzy rule sets usually have several antecedents that are combined using fuzzy operators, such as AND, OR, and NOT, though again the definitions tend to vary: AND, in one popular definition, simply uses the minimum weight of all the antecedents, while OR uses the maximum value. There is also a NOT operator that subtracts a membership function from 1 to give the complementary function.There are several different ways to define the result of a rule, but one of the most common and simplest is the max-min inference method, in which the output membership function is given the truth value generated by the premise. Rules can be solved in parallel in hardware, or sequentially in software. The results of all the rules that have fired are defuzzified to a crisp value by one of several methods. There are dozens in theory, each with various advantages and drawbacks. The centroid method is very popular, in which the center of mass of the result provides the crisp value. Another approach is the height method, which takes the value of the biggest contributor. The centroid method favors the rule with the output of greatest area, while the height method obviously favors the rule with the greatest output value.A soft starter is another form of reduced voltage starter for A.C. induction motors. The soft starter is similar to a primary resistance or primary reactance starter in that it is in series with the supply to the motor. The current into the starter equals the current out. The soft starter employs solid state devices to control the current flow and therefore the voltage applied to the motor. In theory, soft starters can be connected in series with the line voltage applied to the motor, or can be connected inside the delta loop of a delta connected motor, controlling the voltage applied to each winding.Solid state switches. These Solid State Switches are phase controlled in a similar manner to a light dimmer, in that they are turned on for a part of each cycle. The average voltage is controlled by varying the conduction angle of the switches. Increasing the conduction angle will increase the average output voltage. Controlling the average output voltage by means of solid state switches has a number of advantages, one of the major advantages being the vast improvement in efficiency relative to the primary resistance starter, due to the low on state voltage of the solid state switches. Typically, the power dissipation in the starter, during start, will be less than 1% of the power dissipated in a primary resistance starter during start. Another major advantage of the solid state starter is that the average voltage can be easily altered to suit the required starting conditions. By variation of the conduction angle, the output voltage can be increased or reduced, and this can be achieved automatically by the control electronics. The control electronics can be preprogrammed to provide a particular output voltage contour based on a timed sequence (open loop), or can dynamically control the output voltage to achieve an output profile based on measurements made of such characteristics as current and speed (closed loop).The switching elements must be able to control the current applied to the motor at line voltage. In order to maintain a high level of reliability on a real industrial type supply, the switching elements need to be rated at least 3 times the line voltage. On a 400 volt supply, this means that the requirement is for 1200 Volt devices, and 600 Volt devices on a 200 volt supply. It is also important that the switching elements have a good transient current overload capacity.1200 Volt triacs with good current transient overload characteristics are not readily available, and so the choice is really between the SCR-Diode and SCR-SCR. There are some triacs which are suitable for this operation, but they are not easily attainable. The major differences between the SCR-SCR and the SCR-Diode options are price, and the harmonic content of the output voltage. The SCR-SCR method provides a symmetrical output which is technically desirable from the point of supply disturbances and harmonics, while the SCR-Diode method is inferior technically, it is commercially more effective and easier to implement. Harmonics awareness and paranoia has drastically reduced the number of SCR-Diode type soft starters on todays market, but they do still exist. The technology is not always easily recognizable as such with terms such as three pulse technology being used to describe SCR-Diode systems as opposed to six pulse technology describing SCR-SCR systems. Closed Loop starters monitor an output characteristic or effect from the starting action and dynamically modify the start voltage profile to cause the desired response. The most common closed loop soft starter is the controlled current soft starter where the current drawn by the motor during start is monitored and controlled to give either a constant current, or a current ramp soft start. A much rarer closed loop format is the constant acceleration soft start where the motor speed is monitored by a tachogenerator or shaft encoder and the voltage is controlled to maintain a constant rate of acceleration or a linear increase in motor speed. The controlled current soft starters are available with varying levels of sophistication. In the most basic systems, the soft starter is essentially a standard TVR soft starter with a ramp freeze option where the current on one phase is monitored and compared to a set point. If the current exceeds the set point, the ramp is frozen until the current drops below that set point. At the other end of the scale, a comprehensive closed loop soft starter will monitor the current on all three phases and dynamically change the output voltage to correct the start current to the required profile. This system is able to both increase and reduce the start voltage to suit the application. A constant current starter will start initially at zero volts