PLC控制电梯外文翻译

Variable Frequency Speed-regulation System of Elevator

Using PLC Technology

Abstract-In this paper, the system of variable frequency speed-regulation based on PLC was proposed. Firstly, the overall structure of control system was determined. Inverter and programmable logic controller were chosen to complete variable frequency speed-regulation. Secondly, parameters of inverter were set by develop system hardware. PLC drive selection and 110 points distribution were completed; rotary encoder was connected with PLC interface. Finally, the software flow charts and ladder programs were designed by analysis of elevator system on the basis of software design methods.

Keywords-variable frequency speed-regulation; program; logic controller; elevator control system

I. INTRODUCTION

Human power was used as simple lifting equipment before Christ in china, until now hand-gin still was used as lifting device for extraction wells water in some rural of northern areas. So China is one of the earliest countries of the world in the aspect of elevator prototype [1]. In 1854, Elisa Graves Otis from Americans had shown his invention at the World Expo to the world in the Crystal Palace from New York, which was the first safety elevator in history [2]. Since then, elevator has been widely used in the world.

In modem life and economic activity, elevator has become a sign of the city. Elevator has been used as essential vertical transportation equipment, especially in high-rise building. The control systems of relays were used in the conventional elevator, whose control functions and signal processing were realized by hardware. Most of electrical components were common control electrical appliances [3]. Such elevator has been produced with mature technology in the past years, which has been formed series of products. With the rapid development of social economy and improvement of life quality, the shortcomings from traditional elevator controlled by original DC converter and relay had been more and more obvious and exposed many problems: (I) the traditional elevator control system have high failure rate that were mainly due to numerous contacts, complexity of wiring circuit. In addition, electrical contacts were easy to bum out, which could result in poor contact. (2) Electrical controller and hardware wiring based on common method were difficult to achieve a more complex control function, that is, why the functions of system control were difficult to increase. (3)Electromagnetic agencies and contact action were so slow, mechanical and electromagnetic have large inertia. Therefore, the control precision of system was difficult to rise. (4)The traditional elevator control systems have some shortcomings, such as large structure, high energy consumption, serious mechanical noise and so on. (5) Due to line complex and high failure rate of control system, large maintenance workload and high cost were required. It was shown that we should execute a comprehensive transformation to the traditional elevator control system.

II. INVERTER PARAMETERS DESIGN

Elevators were used as vertical transport tool, which belong to potential energy load and require frequent start and stop [4]. With the change of the passenger capacities, up or down transformation, the motor has minimum load. When elevator was run in no load up-going or heavy load down-going, motor was used in the state of power generation. Similarly, the motor has maximum load when elevator was run in heavy load up-going or no load down-going, motor was

used in the state of power. Therefore, the motor was required to run in the four quadrants of axis [5]. The change of motor work states were realized by contactors in the traction motor of traditional elevator. Speed control of motor was completed by series resistance or series reactance in the stator circuit of two-speed asynchronous motor, which can not satisfy the comfort of passengers. Traditional relay control modes were replaced by PLC control method, which could gradually transited from DC speed adjusting system to AC variable frequency speed adjusting system in the modes of motor drag [6].

A. Inverter Type Select

Inverter is the voltage frequency converter, which could convert AC with fixed requency to adjustable frequency voltage AC to supply the motor operation. Considered control requirements and reliability factors from elevator, ANCHUAN VS-616G5 digital inverter was used in this design. The PG card and rotary encoders must be equipped with VS-616G5 inverter in the speed control system of elevator in order to supply motor speed and feedback [7]. Rotary encoder was connected with the coaxial of motor to detect the motor speed. A, B were represented as two phase pulse outputs from rotary encoder. When A phase pulse was ahead of B phase pulse 90' , the electric motor was operated in the state of forward rotation. Similar, when the A phase pulse was lag of the B phase pulse 90' , the electric motor was operated in the state of reverse rotation. According to phase sequence of A, B pulse, the direction of motor rotation could be determined by rotary encoder. Motor speed could also be measured by frequency or period of A, B pulse. Feedback signals were sent into VS-61605 through PO card to operation regulation [8]. The pulse waveform of A, B phases were shown in figure I.

B. Calculation of Inverter Capacity and Braking Resistor

We had supposed that elevator motor power of traction machine was defined as P1,operate speed of the elevator was V1, lift weight was W1 , lift truck was W2,additional weight W3, acceleration of gravity was g , Power of inverter was P. With the maximum load, the traction power P2 in the process of elevator rise [9].

Which, was friction; δ could be negligible;

inverter power P should be close to electrical power P1.the safety surplus capacity must be considered relative to traction power P2. Therefore, P=1.5P2, we could known from experience value,

Therefore, the inverter capacity was selected about 15KW.

As elevator was potential energy load, variable frequency speed regulation system should have a brake function since elevator could generate renewable energy during the process of operation. When VS-61605 was used in the system of speed control, the braking resistors must also be configured. When the elevator was worked in the deceleration, the electric motor was run in the power generation state and feedback power to the inverter. DC part voltage from AC-

DC-AC inverter could increase when sync speed dropped [10].The role of braking resistor was feedback power and suppresses DC voltage. Renewable energy were consumed in the braking resistor through the brake unit by use of the energy consumption braking mode, which has lower cost and good results.

The value of energy consumption braking resistor R2 should be made the value of the braking current I z does not exceed the half of the inverter current.

Which, U0 was defined as DC bus voltage of inverter in the rated state, R2＞30Ω.Because the work of braking resistor was not continuous long-term work, the power could be significantly less than the power consumed.

III. HARDWARE DESIGN

The hardware of elevator control system was composed by Car Lateral Control Panel, Elevator Landing Door Signal, Inverter, and Adjustable Speed Drives. The structure chart of control system was shown in figure 2.

The function of adjustable speed was completed by inverter and logic control section was

completed by the PLC controller. The logic relatives of various signals were responsible for PLC to send on/off control signals to inverter. At the same time, the working status from inverter was transported to PLC .the bilateral contact relationships were established. The speed loop and position loop were established by established to complete speed test and feedback by equip with PO card and Rotary Encoder, which could be connected with Motor coaxial connector. In addition, the system also must be configured with the brake resistor [11]. When the elevator deceleration, DC voltage hypertension must be suppressed due to motor working in the state of renewable generation power, which will back power to inverter.

A. Motor Drive Control System

Similar as other elevator control systems, control system based on PLC was also mainly composed of two parts, that is, signal control system and motor drive control system. The basic structure of PLC elevator control system was shown in figure 3. The main hardware had been included by PLC controller, CPU memory, machinery, car lateral control panel, call elevator plate outside of hall, layer device, gate machine, adjustable speed drives, main motor drive system and so on.

According to the position detection method of Car Lateral from rotary encoder, a high-speed counter was required in the programmable logic controller. FX2N PLC from Mitsubishi Company made in Japan was chosen. The control instructions from elevator were realized by PLC software. The management and control functions of command signals were completed by PLC controller, such as start, acceleration/deceleration and stop of elevator traction motor and open/close door motor, operate direction, floor display, landing call, car lateral internal operation command, security and so on.

B. Signal Control System

Input control signal to the PLC have included that run mode selection, operation control signal, Car Lateral internal instructions, elevator plate calls, signal security information, rotary encoders, optical pulse, on/off door controller and limit level signals, door area and flat layer signals. The control system of six level elevators was used as an example in this paper. According to the need of control switch, about 48 input points and 30 output points need to be control. FX2N a 128MR model of PLC was chosen when we have considered about 10% to 15% surplus capacity of control points [12]. The signal control system of elevator was shown in figure 4.

IV. SOFTW ARE PROCESS

A. Main Program

Control system proposed from this paper was a system of collective selective control. The modular programming methods were used to classify various properties of output signal, medium registers were used to connect different modules to transmit information. System software could be divided into some follow modules, that is, floor detection circuit module, seven segment LED display floor circuit module, elevator direction selection circuit module, deceleration point signal generator circuit modules, on/off door of elevator car lateral circuit module, button memory lights display circuit module and the other modules. In the floor detection circuit module, floor encoding were read into and memory signals were saved in the corresponding registers until the floor changes. LED display was controlled in the seven segment display circuit module. Elevator up or down judgments in response to call the elevator were completed in the elevator direction selection circuit module. Main program flow chart of system software was shown in figure 5.

B. Floor Display Program

Elevator will running in the deceleration state when current floor consistent with target detection floor. During the process of operation, elevator will go through many floor detection points. Deceleration notification will be emitted only when elevator reach the detect point of goal floor. After receive deceleration notification signal, elevator had started slow down. The flow chart of floor display program was shown in figure 6.

PLC output ports were directly connected with seven- segment LED, which need not external hardware decoder. Seven-segment LED was compiled by PLC software to directly display floor number. The seven-segment LED digital tube was commonly used, which is a digital distribution in a plane by a number of light-emitting diodes or liquid crystal segments to form a variety of digital code. Seven-segment LED digital tube was distributed in a plane. Digital codes of floor were composed by some light-emitting diodes or liquid crystal segments. Seven segment LED

display circuit was shown as figure 7.

In the display circuit of seven-segment code, input pin a, b, c, d, e, f, g of LED were

connected with 24V power supply, then the corresponding section will be lighted, the control terminals Y10 -Y16 of programmable logic controller will be closed or open, which could control on or off state to appear the corresponding value in the appropriate section of LED. Digital display of values and correspond pins were shown in table I. Among them, output state I was defined as bright field of the seven segments LED; output state 0 was defined as dark field of the seven segments LED.

V . CONCLUDES

Variable frequency speed-regulation and programmable logic controller technology were used to transform old elevator. The reliability of the elevator was improved through reasonable equipment selection, parameter setting and software design. The elevators after transformation have obvious advantages such as structure compact, low noise, high efficiency, simply

maintenance and low failure rate. The elevator based on variable frequency speed- regulation and programmable logic controller technology have improve passenger comfort and reliable.

Maintenance costs and power consumption of motor were reduced significantly. But there are still many areas for improvement: (I) Changed with fluctuate in traffic; the functions of select direction of elevator were optimized to achieve the purpose of efficient transport of passengers. (2)

Emergency approaches will be increased in the fault conditions. These problems will to be perfect in the future.

ACKNOWLEDGMENT

First and foremost, I would like to show my deepest gratitude to my supervisor, Dr. Zhang. a respectable, responsible and resourceful scholar, who has provided me with valuable guidance in every stage of the writing of this thesis. I shall extend my thanks to Mr. Wang for all his kindness and help. I would also like to thank all my teachers who have helped me to develop the

fundamental and essential academic competence. My sincere appreciation also goes to all my friends for their encouragement and support.

采用PLC 技术的电梯变频调速系统

摘要：本文提出了基于PLC 测定的变频调速调节系统。首先，对控制系统的整体结构

进行了测定。选择变频器和可编程逻辑控制器，来完成变频调速调节。其次，设定变

频器的系统硬件参数。选择PLC 的驱动点和I/O 端子的分配，旋转编码器与PLC 的接口连接。最后，在软件设计的基础上，完成软件流程图和梯形图程序，分析出电梯设

计系统的方法。

关键词：变频调速；可编程逻辑控制器；电梯控制系统。

一、引言

在早期的中国，人的力量被用来作为简单的起重设备，直到现在，北方地区的一些农村手动提取井水的升降装置仍在使用。因此，中国是世界上最早的在电梯的原型[1]方面有建树的国家之一。1854 年，来自美国的格雷夫斯在纽约水晶宫世博会上向世界展示了他的发明，这是史上第一部安全电梯[2]。此后，电梯在世界上得到了广泛的应用。

在现代生活和经济活动中，电梯已经成为了城市的标志。电梯作为重要的垂直运输工具，尤其是在高层建筑中。继电器控制系统曾被用于常规的电梯中，其控制功能和信号处理由硬件来实现。许多的电气元件来共同控制电器[3]。在过去的几年，电梯的生产技术愈发成熟，已形成系列产品。随着经济社会的快速发展和生活质量的提高，由传统的DC 转换器和继电器控制的电梯，缺点越来越明显，暴露出诸多问题：（1）传统的电梯控制系统故障率较高，主要是由于多次接触，复杂的布线电路。此外，电接点易燃，这可能会导致接触不良。（2）电机控制器与硬件接线根据常用的方式，难以实现更复杂的控制功能，也就是难以提高系统控制的性能。（3）电磁机构和接触点动作慢，机械和电磁惯性大。因此，系统的控制精度难以提高。（4）传统的电梯控制系统也存在一些缺点，如结构庞大，能耗高，机械噪声大等。（5）由于线路复杂、故障率高，必然导致控制系统维护量大、成本高。结果表明，我们应该来完成传统的电梯控制系统的完全改造。

二、变频器参数设定

电梯作为垂直运输的工具，属于位能负载设备，并需要频繁启动和停止[4]。电梯随着载客量，向上、向下变化，电机的最小负荷而变化。当电梯在无负载或重负载下，电机在发电状态。同样地，电机具有最大负载时，在重负载上行或无负载下行状态时，电机处于用电状态。因此，电动机的运行轴[5]的四个象限中。传统的电梯由牵引电动机驱动，电机的工作状态的变化，由接触器实现。在定子电路的串联电阻或串联电抗，且电动机的速度控制由双速异步电动机来完成，不能满足乘客的舒适性。用PLC 来取代传统继电器控制模式，它可以在电机拖动过程中，从直流调速的模式逐步过渡到交流变频调速。

A.变频器的选择

变频器可以实现电压频率的转换，它可以转换交流与固定频率，交流电压频率调节后供给电机使用。考虑从电梯的控制要求和可靠性，本次设计使用安川VS-616G5数字变频器。在速度控制系统的电梯中PG 卡和旋转编码器必须配备于VS-616G5 变频器，以供给电动机速度控制和反馈动作[7]。通过电机同轴连接的旋转编码器来检测电机的转速。A，B 分别表示为两相旋转编码器的脉冲输出。当 A 相脉冲超前 B 相脉冲90 度时，电动机正向旋转的状态。类似的，当A 相脉冲滞后B 相脉冲90 度时，电动机操作的反向旋转状态。根据A，B 脉冲的相序，确定电机的旋转方向。测量电机转速的同时也可以测量出A，B 脉冲频率或周期。反馈信号发送到VS-61605 通过PG卡到变频器[8]。图一所示的脉冲波形A，B。

B.变频器容量的计算和制动电阻

我们定义电梯曳引机的电机功率为P1，运行的电梯速度为V1，起重量为W1，W2，额外的重量W3，重力加速度为G，电源逆变器是P.随着的最大负载在电梯上升[9]的过程中，牵引功率为P2。

其中，F1 为摩擦力，δ可忽略不计。变频器的功率P 接近电梯电源P1，安全性能，必须考虑牵引功率P2。P=1.5P2，因此，我们可以得知经验值，

此时，变频器的容量约为15KW。

随着电梯潜在的能量的加载，可变的频率速度调控系统应该有一个制动函数，因为电梯可能在操作过程中产生可再生的能量。当系统速度控制中使用了VS-616G5，必须配置制动电阻器。当电梯被用在减速过程时，所述电动从发电状态，反馈到变频器的发电状态。DC 从AC-DC-AC 逆变器可以增加,当同步速度下降时。制动电阻器的作用是反馈信号抑制直流电压。可再生能源的被消耗了在制动电阻上，通过所述制动单元的制动模式，该模式具有较低的成本和良好的结果。

能源消耗制动电阻器R2，制动的电流I z 的值不超过该的变频器电流的二分之一。其中，U0 被定义为变频器额定电压，R2 大于30 欧姆。因为制动电阻不是长期工作的，电源可能小于所消耗的功率。

三、硬件设计

电梯控制系统的硬件组成，由汽车横向控制面板，电梯厅门信号，变频器，调速传动。图2 中所示的控制系统的结构图。

速度可调的功能，由变频器和PLC 控制器的逻辑控制部分完成。负责PLC 发送开/关控制信号，逆变器的各种信号的逻辑亲属。在同一时间，变频器的工作信号被输送到PLC，双边接触关系成立。由PG 卡和旋转编码器与电机同轴连接，可连接建立完成速度测试和反馈设备的速度环和位置环。此外，该系统还必须配置制动电阻器[11]。当电梯减速时，必须抑制由电机工作的可再生能源发电功率，这将反馈电信号到变频器。

A.电机驱动控制系统

类似其他的电梯控制系统，基于PLC 的控制系统主要由两部分组成，即信号控制系统和电动机驱动控制系统。PLC 的电梯控制系统的基本结构如图3 所示。主要硬件包括PLC 控制器，CPU 内存，机械，汽车侧控制面板，呼叫电梯外盘层设备，大厅，门机，调速驱动器，主电机驱动系统等。

根据旋转编码器位置检测方法，需要一个高速计数器在可编程逻辑控制器中。在日本三菱公司的FX2N PLC 中，从电梯控制指令由PLC 软件实现。完成管理和控制功能的指令信号由PLC 控制器，如启动，加速/减速和停止电梯牵引电机和电机开/关门，方向确定，楼层显示，层站呼梯操作命令，安全指令等。

B.信号控制系统

输入控制信号给PLC 运行模式选择，操作控制信号，内部指令，升降呼叫信号，安全性信息，旋转编码器，光脉冲，打开/关闭门控制器和限制电平信号，轿厢门和平面层信号。在六级电梯的控制系统中，使用约48 个输入点和30 个输出点。选择FX2N 128MR 的PLC 型号。图4 中所示的信号控制系统的电梯。

四、软件过程

A.主程序

本文提出的控制系统是一个系统的集城选择控制装置。采用模块化编程方法，将输出信号的各种属性进行分类，其中寄存器用来连接不同的模块并传输信息。系统软件可分为一些后续的模块，也就是层检测电路模块，七段数码管显示楼层电路模块，电梯方向选择电路模块，减速点信号发生器电路模块，开/关电梯轿厢门模块，按钮记忆灯显示电路模块和其他模块。在其它检测电路模块中，读入内存信号并保存在相应的寄存器中，直到轿厢地板的变化。LED 显示屏控制七段显示器电路模块。电梯向上或向下的判断响应呼叫电梯，在电梯方向选择电路模块。系统软件的主程序流程图如图5 所示。

B.楼层显示程序

电梯在减速运行时，检测楼层信号位置。在操作的过程中，电梯会经过许多楼层检测点。减速将发出通知，只有当电梯到达目标楼层的检测点。收到减速通知信号后，电梯已开始放缓。如图6 中所示地显示程序的流程图中。七段LED，不需要外部硬件解码器，直接连接PLC 的输出端口。七段LED 编译PLC 软件直接显示楼层号。七段LED 数码管常用的，这是一个数字由多个发光二极管或液晶段，分布在一个平面上形成各种不同的数字码。七段LED 数码管分布在一个平面上。

五、总结

变频调速调节和可编程逻辑控制器技术被用来改造电梯。电梯的可靠性进行了改进，通过合理的设备选型，参数设置和软件设计。改造后的电梯有明显的优点，如结构紧凑，噪音低，效率高，维护简单，故障率低。电梯的基础上变频调速，可编程逻辑控制器技术已提高乘客的舒适性和可靠性。显着降低电机的维护成本和功耗。但也有仍然有很多需要改进的地

方：（一）改变流量波动;电梯选择方向的功能进行了优化，实现高效运送乘客的目的。（2）紧急方法将增加在故障条件。这些问题将在未来来完善。