高压无换向器电机及其控制技术

中文摘要
    本文以采用三相桥式电流型变换器的无换向器电机为研究对象，吸收近年来微电子和微处理器领域的最新技术成果，对无换向器电机控制系统的若干薄弱环节进行研究，并取得了一定成果。
    通过分析有关有限状态机(FSM)的文献，设计了改进的有限状态机方法(IFSM，作为小型嵌入式系统的软件分析工具。IFSM的分析结果可以很方便的转换为软件设计阶段的N-S盒图，利用盒图编制软件可以保证软件的结构化并易于维护。在开发无换向器电机时，利用改进的有限状态机方法，不但分析设计了全程时域仿真模型，还利用盒图和C语言，在实际装置中，实现了主控制器、转子位置检测器、晶闸管阀故障监测等软件。这些子系统功能不同，但具有相同的软件结构，维护和调试都很方便。
      首先建立了无换向器电机的传递函数模型，对双闭环调速系统的控制器参数进行设计。然后以Matlab软件提供的一套电力系统工具箱为基础，建立无换向器电机主回路模型，并利用Matlab语言编制控制软件，将两者结合，建立了全范围动态过程的仿真模型，称之为全程时域仿真模型。最后利用此仿真平台，研究了电机低速断流运行特性，以及无换向器电机端电压的变化规律，为研究转子电气位置检测方法以及直流平波电抗器选型提供了理论依据。
    为了解决高压无换向器电机相控整流器繁琐的安装调试问题，重新对相控技术进行了研究。根据三相变压器的接线组原理，揭示出电网不同等级电压的内在联系，而后对感性负载电压电流的相位关系进行分析。得出结论，可以把电网任一低压交流电源，如控制回路的供电电源，作为同步信号源，利用软件方法推算出整流器交流侧电源的相序相位关系，最终形成一套相序相位自动识别算法，并应用到无换向器电机控制系统中。该方法不需要高压电压互感器，降低了装置成本，并大大简化了相控整流器的调试过程。
    由于电机转速从零速到额定转速宽范围调节，电机端电压幅值和频率变化非常大，波形也严重畸变，所以全程式的转子电气位置检测器很受重视，但这一问题始终没有很好地解决。无换向器电机在低速时段，一直沿用机械式(如光电式)转子位置检测器，高速时段才切换为电气位置检测器。本文利用一系列特别设计的方法，解决了转子位置从零速到额定转速的检测问题，并且只使用定子侧的三相电压为观测量，可称为全程式转子电气位置检测器。该检测方法与电机极对数无关而且可以实现电机全程闭环控制，在实验电机上获得了良好效果。
    在前述研究的基础上，吸收微处理器和微电子领域的最新成果，研制了一套高压无换向器电机控制系统。围绕新型快速芯片的使用，设计了多种抗干扰方案来提高控制系统可*性，以适应恶劣的工业运行环境。设计的控制系统分别在两套装置中进行了试运行。一是在实验室环境下，以一台1kV, 400kW, 4对极的同步电动机为控制对象，拖动一台直流发电机和电阻箱负载;二是在某钢厂的空压机车间以一台6kV, 300kW, 7对极的悬臂轴式同步电动机为控制对象，拖动空压机负载。试运行表明，本设计是成功的。
    设计了一套中压晶闸管阀，应用在上述6k V高压无换向器电机中。该晶闸管阀的主要技术特点有:由于无换向器电机低速运行时逆变桥承受电压很低，不能从阻尼电容回路取得触发电源，所以设计了独立的触发电源，并通过高压电缆将高频电源传送到各个晶闸管触发电路;利用检测晶闸管反向电压设计了晶闸管故障检测电路及阀故障检测系统;触发脉冲直接经光纤发送到晶闸管触发电路板，以简化设计并提高响应速度;冷却系统采用风冷结构。通过改变串联元件的数量和晶闸管参数，该装置可以用于6kV-IOkV, 200kW-2000kW范围。
    总结以上内容，本文共在6个方面取得了一定成果:小型嵌入式系统开发的工程方法，无换向器电机全程时域仿真模型，相控整流器相序相位自动识别算法及应用，全程式转子电气位置检测方法的分析与实现，高压无换向器电机控制系统研制，中压晶闸管阀系统研制。

关键词:无换向器电机，转子位置检测，相序相位自适应，晶闸管阀，有限状态机

Abstract
    By us ing new technical achievements in micro一electronic and micro一processor fields,
several weak links of commutatorless motor (CLM)are researched in the following.
    Through analysis of materials of finite state machine (FSM), improved FSM (IFSM) is
designed, which can be used as software analysis tool of small embedded system. Analysis
result described by IFSM can be easily transferred to N-S block diagram which is widely used
as software design tool and program based on block diagram can ensure structure software.
By using IFSM, both whole process time-domain simulation model and real device of CLM
are developed.
    Transfer function model of CLM is built and regulator parameters of double-closed loop
adjustable speed (ASD) system of CLM are calculated by using engineering design method.
Then based on power system toolbox provided with simulink software, main circuit model of
CLM is built and by using matlab language, control software is programmed. Whole process
time一domain simulation model is developed by combina tion of main circuit model and control
software. Low speed current-interruption running characteristics and terminal voltages of
stators of CLM are analyzed based on the simulation model.
    In order to simplify the complex installation and adjustment process of phase-controlled
converter (PCC)  of CLM,  PCC  principle is  re-analyzed. Based on  connection symbol
fundamentals of transformer, internal relations of different voltage-levels of power network
are revealed and then phase relation between voltage and current of inductive load is analyzed.It can be concluded that every phase of low voltage AC source can be selected as synchronous voltage, such as power source of control circuit. Phase sequence and phase of main circuit can be calculated by software. At last phase sequence and phase auto一recognition algorithm is formed, which is used to improve traditional PCC software. When this method is used, high voltage PT can be omitted and adjustment process of PCC can be simplified.
    Because  CLM  is  adjusted  from  standstill  to  rated  revolution,  three-phase
terminap voltages  amplitude  and  frequency  vary  greatly  and  their waves  have  serious
distortion. Whole process electric rotor position detector has been widely researched, but it is not well solved. In the current, mechanical rotor position sensor is used during low speed period of CLM and changed to electric rotor position detector in high speed period. By using a series specially designed methods, the problem of electric rotor position detection from start to rated speed of CLM is solved, which only use three-phase stator's voltage as measurement variables. This method has no relation with poles of motor and can make CLM start under closed-loop control. Good results are gained through experiments on a test motor.
    Based  on  above  researches  and  newest  achievements  of  micro一processor  and
micro一electronics fields, advanced control system of CLM is developed. For many new types
high-speed ICs are used, many anti disturbance measures are designed to improve reliability.
The control system is used in two SMs for test run. One is used to control a 1kV, 400kW and
4-pair poles SM in laboratory, which drives a DC generator; the other is used to control a 6kV,300kW and 7-pair poles SM in an air compressor shop, which drives an air compressor. Test run shows that control system has good performance.
    A  set  of  medium-voltage  thyristor-valve  system  is  designed  and  it's  technical
characteristics include: independent triggering power is designed because inverter triggering power source can not gain from damped capacitor circuit when CLM is operating in low speed;  thyristor fault detection circuit is designed based on measure of inverse voltage of thyristor and valve fault detection system is designed to check all thyristors in turn; triggering pulses do not adopt code pattern, which are directly transmitted to triggering circuit of every thyristor through optical fiber in order to simplify design and increase response speed; air cooling system is adopted. Thyristor valve system is used in a 6kV CLM introduced in the former. Through change of thyristor's number and parameters, this device can be used in the range of 6kV IOkV and 200kW一2000kW.
    To sum up, several achievements are made in the following aspects: engineering method
of development of small embedded system, whole process time-domain simulation model of
CLM, phase sequence and phase auto-recognition algorithm of phase-controlled rectifier,
achievement of whole process electric rotor position detector, development of control system
for high voltage CLM, development of medium-voltage thyristor valve system.

Key words: CLM，Rotor Position Detection, Phase Sequence Self-adaptation, FSM