大功率同步电动机自控变频式软起动技术研究

发布时间：2018-06-10 17:45

本文选题：电励磁同步电机 + 自控变频　；参考：《哈尔滨工业大学》2014年博士论文

【摘要】：电励磁同步电机具有功率因数可调、效率高等优点，在工业大功率场合获得了广泛应用。在诸多同步电机起动方式中，自控变频软起动方式是技术含量最高，性能最优的起动方式，是同步电机软起动技术的发展方向。它具有起动电流较小，起动转矩可控，对电网几乎没有附加要求等优点。目前，国内大功率电动机软起动装置主要还是依靠进口，尤其是变频软起动器，国内目前还没有形成完善的应用性产品，因此研究自控变频方式同步电机软起动装置具有重要的经济意义和战略意义。大功率同步电动机的起动及并网困难成为其应用的重大阻碍，是限制产业发展的重大技术难题，本文针对自控变频式同步电动机起动系统中存在的问题进行了理论分析和实践研究，主要研究内容如下：针对同步电动机无位置传感器起动方法，本文采用自给脉冲起动与电气转子位置检测相结合的方法实现了同步电动机无位置传感器起动。通过突加、突减励磁的方法检测静止转子位置，转速在中高速时用电气式的方法实现转子位置检测，通过电机惯量辨识计算出自给脉冲的加速频率，并用自给脉冲的方式实现了电机从静止到中高速起动的过渡，实现了全程无位置传感器的起动。针对自给脉冲方法在低速起动过程中存在转子脉动等问题，研究了基于高频注入的转子位置检测方法。根据电励磁同步电机的特点，向励磁注入高频电压信号，产生高频励磁电流，之后采集耦合在定子上具有转子位置信息的高频电压信号，经过滤波及坐标变换提取有效转子位置信息，最后采用锁相环算法锁定转子位置。在晶闸管传动系统中，当电流换相时，电机反电动势的畸变比较严重，检测端电压将含有大量的高次谐波，准确提取有效的高频信号非常困难。因此本文提出了基于高频注入电压预估的同步电机转子位置检测方法。在换相时刻采用预估电压作为锁相环的给定信号，防止换向畸变的高频谐波进入到锁相环。实验结果证明，加入电压预估后，，有效地避免了换相电压畸变对转子位置检测产生的不利影响，提高了高频注入转子位置检测的精度和可靠性。并网是自控变频式同步电机软起动系统中非常关键的技术性问题。本文针对大功率以及大惯量系统，研究了准同期并网策略。分析了双闭环调速系统中，在电流环动态特性非理想条件下，采用速度PI控制器引起的相角滑差不稳定问题，进而，本文提出了一种自适应复合速度控制方法。在升速阶段采用单比例自适应速度控制算法，克服了传统比例控制器无法消除静差的困难；在准同期阶段，采用了基于相角滑差的准同期控制算法，解决了滑差不稳定的问题，并给出了可靠的并网判决策略。针对自控变频软起动装置高压系统的设计及实现，本文介绍了控制系统的软、硬件设计方法。首先针对起动过程中，电机端电压检测存在的隔离、相移及谐波等问题，提出了详细的电压检测方案。介绍了对晶闸管阀组、平波电抗器、进线电抗器的设计方法，设计了基于电流源的同步隔离触发装置，解决了高压串联晶闸管同步触发和高低压隔离问题。通过实验结果提出了不同主电路结构的适用场合。
[Abstract]:With the advantages of adjustable power factor and high efficiency, the electric excitation synchronous motor has been widely used in industrial high-power situations. In the starting mode of many synchronous motors, the self controlled frequency conversion soft starting mode is the most technical content, the best starting mode, and the development direction of the synchronous motor soft starting technology. It has a small starting current. At present, the domestic high power motor soft starter is mainly dependent on the import, especially the variable frequency soft starter. At present, the domestic soft starter has not formed a perfect application product at home. Therefore, it is of great economic significance to study the soft starting device of the synchronous motor with self controlled frequency conversion. The difficulty of the starting and grid connection of high power synchronous motor has become a major obstacle to its application, and it is a major technical problem to restrict the development of the industry. In this paper, the theoretical analysis and practical research are carried out on the problems in the starting system of the self controlled frequency conversion synchronous motor. The main contents are as follows:
Aiming at the starting method of sensorless synchronous motor, this paper realizes the starting of the synchronous motor without position sensor with the method of self feeding pulse starting and electric rotor position detection. The position of the static rotor is detected by the sudden addition and the reduction of excitation, and the rotor position detection is realized by the electric method when the speed is in the middle and high speed. The acceleration frequency of the pulse is calculated by the inertia of the motor, and the transition from static to middle speed is realized by the way of self supply pulse, and the starting of the whole distance sensorless is realized.
Aiming at the problem of rotor pulsation in low speed starting process, the method of rotor position detection based on high frequency injection is studied. According to the characteristics of the synchronous motor, high frequency voltage signal is injected into the excitation, high frequency excitation current is produced, and then high frequency voltage signal with rotor position information on the stator is collected. By filtering and coordinate transformation, the effective rotor position information is extracted. Finally, the phase locked loop algorithm is used to lock the rotor position. In the thyristor transmission system, when the current is changed, the distortion of the motor back EMF is more serious. The detection terminal voltage will contain a large number of high order harmonics, so the accurate extraction of the effective high frequency signal is very difficult. Therefore, this paper is very difficult to accurately extract the effective high frequency signal. A method for detecting the rotor position of a synchronous motor based on high frequency injection voltage is proposed. In the commutation time, the estimated voltage is used as a given signal of the phase-locked loop to prevent the high frequency harmonics from the commutation distortion into the phase-locked loop. The experimental results show that the phase change of the commutation voltage can be avoided effectively after the voltage prediction is added. The adverse effect has improved the accuracy and reliability of high frequency injection rotor position detection.
Grid connection is a very key technical problem in the soft starting system of self controlled inverter synchronous motor. In this paper, a quasi synchronization network strategy is studied for high power and large inertia systems. The problem of unstable phase angle slip instability caused by the speed PI controller is analyzed under the non ideal dynamic characteristics of the current loop in a double closed loop speed control system. In this paper, an adaptive compound velocity control method is proposed. A single proportional adaptive speed control algorithm is adopted at the stage of rising to overcome the difficulty of eliminating static difference by the traditional proportional controller. In the quasi synchronization phase, a quasi synchronization control algorithm based on the phase angle slip is adopted to solve the problem of the instability of the slip. Based on the grid decision strategy.
In view of the design and implementation of the high voltage system of self controlled variable frequency soft starting device, this paper introduces the soft and hardware design methods of the control system. Firstly, the detailed voltage detection scheme is proposed for the isolation, phase shift and harmonics of the motor terminal voltage detection in the starting process. It introduces the thyristor valve group, the flat wave reactor and the wire feed. A synchronous isolation trigger based on current source is designed to solve the problem of synchronous trigger and high and low voltage isolation of high voltage series thyristor. The application of different main circuit structures is put forward through experimental results.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM341

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