To use a happy campus, you need to install Adobe Flash Player ver.9 or above. Please install Flash Player. [pages]: 31[words]:14854 [contents]/system design scheme research 3 system design and application example 4 summary and prospect [Abstract] With the appearance of thyristor, the combination of modern power electronic technology and control theory with computer has promoted the prosperity of research and application of electric drive control technology, which is beneficial to industrial production and application. Production efficiency and people's quality of life have been improved, and great changes have taken place in the production and life of human society. The maturity of thyristor -DC motor speed regulation system provides high efficiency and high performance power supply for modern industry. DC motor speed regulation system has a broad market with its excellent speed regulation performance, and the DC speed regulation principle based on feedback control theory is the basis of AC speed regulation control. This paper introduces the design and research of current cut-off negative feedback single closed-loop DC motor speed regulation system, which consists of DC motor module, thyristor rectifier module, speed feedback link, current cut-off negative feedback link and pulse generation module. The system mainly uses the deviation between speed feedback and current cut-off negative feedback and a given amount to change the trigger phase shift control signal to adjust the control angle of thyristor, so as to change the output voltage of rectifier to realize the principle of adjusting the speed of DC motor. Firstly, the mathematical model of the motor is given, and the working principle of the speed closed-loop speed regulation system is analyzed. In order to limit the excessive starting current, the current cut-off negative feedback is introduced, and the function of the current cut-off negative feedback link is introduced. Secondly, according to the principle scheme, the system principle block diagram is constructed, the simulation model of the system is established by using Matlab/Simulink software, and the system is simulated. Then an application example of DC motor speed regulation system is given, and the parameters of each module are set according to the example to simulate. After comprehensive consideration and reasonable analysis, the simulation waveforms of various physical quantities basically meet the requirements. [Text] 1 Yan Xu 1 Research background In modern production and life, motors have been playing a very important role, and they are widely used in transportation, national defense, aerospace, medical and health care, agricultural production, commercial and office equipment, and daily household appliances. According to relevant data, more than 90% of the power comes from motors, and about 60% of the electric energy produced in China is consumed by motors. In this sense, motor is also the most common source of motion, and the most effective way to control motion is to control the source of motion. Therefore, motion control is often achieved by controlling the motor. DC speed regulation is an early technology in modern electric drive automatic control system. The power electronics technology developed in the 1960s transformed and controlled the electric energy, and produced various modern, efficient and energy-saving new power supplies and AC /DC speed regulating devices, which provided modern high technology for industrial production, transportation, construction, office and home automation, improved production efficiency and people's quality of life, and made great changes in the production and life of human society. With the development of new power electronic devices and advanced control technology, the performance of power electronics and electric drive control devices is constantly optimized and improved, and the influence of this change will be greater and greater. With the appearance of thyristor, the combination of modern power electronics technology, control theory and computer promotes the prosperity of research and application of power rotation control technology. Thyristor -DC motor speed regulation system provides high efficiency and high performance power supply for modern industry. Although AC speed regulation is developing rapidly, AC speed regulation technology is becoming more and more mature, and the economy and maintainability of AC motor are getting better and better, AC speed regulation is still widely welcomed by users. However, the DC motor speed regulation system still has a broad market because of its excellent speed regulation performance, and the DC speed regulation principle based on feedback control theory is also the basis of AC speed regulation control. The current DC and AC speed regulating devices are digital, and the chips and software used have their own characteristics, but the basic control principles have their own characteristics. This paper mainly studies the basic principle and speed regulation performance of DC speed regulation through simulation.