The Research Of A Dedicated Converter For Centrifuges

After the development of four generations, AC speed control modes have developed rapidly. Direct torque control (DTC) is an AC speed control technique that directly analyzes the AC motor mathematical model and controls motor flux and torque in the stator coordination, possessing high dynamic response, simple control structure, direct control mode.Research of dedicated converter based on DTC for the centrifuge is introduced in this paper. In China, centrifuge commonly uses general converter. Though the general converter shows some advantages, it has many parameters and is expensive. Therefore, the research of the dedicated converter applicable to the centrifuge has very important practical significance.First, the paper presents the development and current situation of AC speed control and the significance of the subject; Next, we introduce the theory, system architecture, and principles of direct torque control; Then, we introduce the hardware circuit design of the dedicated converter for centrifuge control system, including the main circuit, the voltage detection circuit, the current detection circuit, the speed detection circuit, drive and isolation circuit, protection circuit and the power supply circuit. Especially, a hardware platform of the special centrifuge frequency converter control system is built; Second, we introduce the software implementation of direct torque control under the CCS3.3, a DSP integrated development environment, mainly including the specific implementation of modules such as speed detection, speed display, voltage and current detection and their 3/2 transformation, flux and torque calculation, torque given, flux and torque adjusting, flux sectors selection, switch signals selection and voltage states output; Finally, experiments are performed to verify the validity of the design and the performance of the DTC, and some analysis and explanations are given according to some experimental data obtained.In the process of IGBT protection circuit design, we propose a new low-cost short-circuit protection circuit based on IR2110 and a new protection method.