【作者】 王大朋；

【导师】 王凤翔；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2012， 博士

【摘要】 磁轴承的控制系统具有模拟控制和数字控制两种方式,模拟控制控制器一般由运算放大器构成,其运行速度快,成本低,但是控制器一旦选定,参数不容易更改,并且不能实现复杂的控制算法。在磁轴承的实际应用中,主要用于转速不是特别高的轴承。数字控制器相对与模拟控制器而言更加灵活,复杂的控制算法容易通过软件实现,能够获得比模拟控制更好的控制性能。因此,目前磁轴承控制主要采用数字控制。为了研究验证磁轴承的控制算法和系统特性,利用实验室原有的磁轴承系统研发了一套基于DSP的五自由度磁轴承控制系统,并且对功率放大器进行了研究,对所研制的磁轴承控制系统进行了静态悬浮和高速无负载实验。4.1基于DSP的磁轴承控制系统的硬件4.1.1控制系统的构成随着微电子技术的快速发展,数字信号处理器(DSP)的性能变得越来越好,其成本不断下降,计算速度越来越快,已经广泛的应用在各行各业中。因为磁轴承的主要应用领域是高速电机,所以在设计磁轴承控制器时必须选用运算速度快的DSP控制芯片,同时也需要配合高速度的A/D转换器和D/A转换器。利用DSP作为主控芯片的磁轴承控制系统的结构如图4.1所示。首先利用涡流传感器测量磁轴承五个自由度位移信号,然后经过滤波电路滤波后送入A/D转换器转换成数字信号,经过DSP计算模块来实现所用的控制方法,计算处理完毕的数据再通过D/A转换器变换成模拟电压信号作为功率放大器的输入控制信号,形成磁轴承控制电流。4.1.2主控芯片TMS320F2812 DSP磁轴承控制器的主控芯片使用TI公司生产的TMS320F2812数字信号处理器。此验证了故障判断方法的有效性。更多还原

【Abstract】 The high speed permanent magnet (PM) machine has been widely investigated in the field of electrical engineering since it has small volume, high power density and high efficiency. Compared with the convertional low-speed machine, the rotor speed can reach up to or even above 100000r/min, so that the mechanical bearing is difficult to meet the requirements of the high-speed operation. The active magnetic bearing(AMB), which levitates a rotor by magnetic forces, has many merits, such as no contact, frictionless and so on, particularly suitable for high speed motors. However, it also is a nonlinear and open-loop unstable complicated. control system. Therefore, how to improve the stability and reliability of magnetic bearing is the key of high-speed motor for safe operation.The research work of this thesis is a part of the project-“The distributed high speed generator system driven by micro-turbines and its energy conversion system”, which is supported by the National Natural Science Foundation of China (No. 50437010). The study of the thesis is concentrated to the suspension force analysis of AMB, linear active disturbance rejection control, PID control, and online monitoring of AMB fault. The main contents are as follows:(1) Due to the strong nonlinearity of magnetic bearing, a levitation force analysis of magnetic bearing based on field-circuit combined method was used. The linear operation range of AMB was determined. The factor of linear expressions for magnetic levitation force was revised, and the nonlinear expressions of magnetic levitation force was deduced by polynomial approximation. Moreover, the dynamical model of rotor-bearing system, model of control system and model of rotor displacement measuring system were established.(2) The linear active disturbance rejection control and PID of AMB control were studied. Because the tranditional PID control method for radial AMB cannot achieve good results, the linear active disturbance rejection controller was designed, which can enhanced the anti-disturbance capability for radial AMB. For axial AMB, the incomplete differential type PID controller was desingn, the PID parameters were optimized based on genetic algorithms.(3) Base on three-level power amplifier with carrier triangular wave reversed-phase method, the AMB control system was designed by using DSP as its micro-controller. Then, the AMB control platform was established, the static suspension experiment and high speed running experiment were carried out, and the stable levitation of AMB in 5 degrees of freedom was realized.(4) The monitoring system of AMB was designed based on LabVIEW, a method of failure judgement was proposed by using the wavelet energy distribution vectors, and the correctness and effectiveness of the failure judgement approach are verified by the experiments.更多还原