The Research And Design Of High-speed Centrifuge Controller

Centrifuge is one kind of equipment used for separating or purifying some substances by high-speedy rotating of it. The developments of its rotation speed directly impact the ones of biomedical science and other high technology. As for the drive motor of centrifuge, it got the achievement in the field of DC motor. However, the frequent replacement of carbon brush in DC motor had restricted the development of centrifuge. With the raising and growing of the AC Variable Speed theory, asynchronous motor accesses to a wide range of applications in the centrifuge field. The most important features of the asynchronous motor are its simple structure, low price, high reliability and easy maintenance. in the area of Centrifuge industry, the asynchronous motor controller commonly uses general-purpose inverter, which is applied extensively. However, its disadvantages are obvious that it costs more, needs to set up too many parameters in the procedure, and makes low use of DC bus voltage. The purpose of the research in this article is to reduce the cost and enhance the controlling capability of the controller. At the same time, the research aims to enhance the DC bus voltage utilization, in order to develop a dedicated controller for centrifuge with high performance. In the aspects both in capability improvement and energy-saving, the controller is valuable to research.This paper first introduces the development status and trend, which determines the asynchronous motor as the driving power of the centrifuge as well as the combination of higher utilization of direct torque control and vector control method as the development of controller technological means. In the following chapters, basic conception and traditional models of direct torque control and vector control are mentioned. In Chapter III, through the traditional model analysis, the improving and optimizing programs is raises, which mostly focuses on the program of vector control combined with direct torque control to solve low-speed pulse problem. In order to improve high-speed pulsation problems, the speed ring uses fuzzy adaptive PI controller instead of the traditional PI controller. The decision-making strategy of voltage switching vector uses fuzzy control instead of the traditional two-point-control strategy. The paper analyzes the flux and torque problems in the process of vector control transiting to direct torque control and raise some solutions. By analyzing the simulation and results of the improved controller model, it is further verify the feasibility of the combined control strategy. Finally, the author designs for hardware in controller, including the design for main circuit, current-voltage detection circuit, and speed measurement circuit. In the last chapter, it summarizes the full text, and looks forward the development and future of the application of direct torque control in the centrifuge prospect.