Global Journal of Science, Engineering and Technology (ISSN : 2322-2441) Issue 8, 2013 , pp. 67-73 © GJSET Publishing, 2013. http://www.gjset.org 67 DC MOTOR CONTROL USING CHOPPER NAZANIN AFRASIABI Department of Mechatronics Engineering, Kish International Campus, University of Tehran Kish Island IRAN n.afrasiabi@ut.ac.ir MOHAMMADREZA HAIRI YAZDI School of Mechanical Engineering University of Tehran College of Engineering, Karegar St.North, Tehran IRAN myazdi@ut.ac.ir Abstract: - This paper deals with DC motor control in a high performance manner. The DC motor control system is designed and performed using a chopper circuit. The four different parts of control of DC motors will be considered here. Using chopper as a converter the speed of DC motor is controllable. The chopper firing circuit gets signal from controller and then by supplying variable voltage to the armature of the motor the desired speed chopper is achieved. There are two different types of control loops, current controller and speed controller. The controller used is Proportional-Integral type. Using this controller the delay is removed and fast control is achieved. Separately excited DC motor is designed and the complete layout of DC drive mechanism is achieved. The current and speed controller is designed and in order to get stable and high speed control of DC motor, the speed controller is optimized using modulus hugging method. After obtaining the entire model of DC drive system, the model is utilized with MATLAB (SIMULINK). DC motor drive is computer simulated and analyzed under various speeds and load torques. Key-Words: - chopper circuit, four quadrant control, DC motors, control loops, MATLAB (SIMULINK). 1. Introduction High performance motor derives are necessary parts of industrial applications. A motor drive system with high performance has special characteristics such as good dynamic speed command tracking and load regulating response. DC motors are well known for their excellent control of speed for acceleration and deceleration. In a DC motor the power supply directly connects to the field of the motor and causes a precise voltage control which is essential for applications which need control of speed and torque. Because of various advantages such as simplicity, ease of application, reliability and favorable cost, DC drives have long been a backbone of industrial applications. In comparison with AC drive systems DC drives are less and are normally cheaper for low horsepower ratings. DC motors are identified as adjustable speed machines for many years and a wide range of options have evolved for this purpose. Adjustable speed AC drives would be more complex and expensive. D.C motor is considered as a SISO (Single Input and Single Output) system which has torque/speed characteristics and is compatible with most mechanical loads. By proper adjustment of the terminal voltage [3] the mentioned characteristic makes a D.C motor controllable over a wide range of speeds. In this article controlling DC motor speed using Chopper as power converter and PI as speed and current controller is investigated. A chopper is a static power electronic device that converts fixed dc input voltage to a variable dc output voltage. Chopper systems have smooth control capability and are highly efficient and fast in response. A chopper can be used to step down or step up the fixed dc input voltage [2] like a transformer.