International Journal of Power Electronics and Drive Systems (IJPEDS) Vol. 14, No. 2, June 2023, pp. 727~740 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v14.i2.pp727-740  727 Journal homepage: http://ijpeds.iaescore.com Torque control of a 5 KW, 220 V separately excited DC motor using microcomputer Mohamed Mostafa Ramadan Ahmed 1,2 , Atef A. Elemary 2 , Zuhair Muhammed Alaas 2 , Abdallah Mohamed Hamada 3 1 Department of Electrical Technology, Faculty of Technology and Education, Helwan University, Helwan, Egypt 2 Department of Electrical Engineering, Faculty of Engineering, Jazan University, Jazan, Saudi Arabia 3 Department of Electrical Technology, Faculty of Technological, Higher of Ministry, Alexandria, Egypt Article Info ABSTRACT Article history: Received Nov 14, 2022 Revised Dec 31, 2022 Accepted Jan 16, 2023 Fast torque control is crucial for various applications, including diesel-electric locomotives, electric automobiles, and steel plants. The purpose of this paper is to utilize a microcomputer to control the torque of a separately-excited DC motor fed from a single-phase semi-controlled converter. There are numerous strategies to determine torque using direct or indirect methods. The greatest issue of direct strategy using torque meters is that the measuring device must be installed between the motor and the load. In this paper, we avoid this challenge by employing the indirect approach, specifically by monitoring several DC machine-specific quantities such as voltage, current, and speed, which are easier to determine experimentally. This technology is unquestionably helpful in real-world applications since it eliminates any mechanical impact on the installation. This paper describes the system configuration and provides an explanation of the architecture and system features. The simulation of the proposed system using TUSTSIM dynamic simulation program which is capable of simulating the control system with a digital controller in the loop is presented. An implementation of microcomputer-assisted torque control of DC separately excited motor with proportional integral (PI) controllers is presented. A typical oscillography of the driving characteristics is provided along with the experimental results. Keywords: Controlled converter DC drive Microcomputer PI controller Torque control This is an open access article under the CC BY-SA license. Corresponding Author: Mohamed Mostafa Ramadan Ahmed Department of Electrical Engineering, Faculty of Engineering, Jazan University Al Maarefah Rd, Jazan Arab Saudi Email: mohamedra62@yahoomail.co.uk 1. INTRODUCTION DC machines are widely used in a variety of industrial applications, including robots, electric vehicles, steel rolling mills, trains, and cranes due to their easy, wide, precise, and continuous control capabilities. In a direct DC drive system, controlling motor torque is frequently necessary. Numerous topologies exist for measuring torque using direct or indirect methods [1]–[5]. Each of these methods has its benefits and drawbacks [6]. The main difficulty with the direct method is that a measuring device, must be inserted between the load and the motor or between the driving motor and the generator, respectively, using a torque meters with strain gauges incorporated into a Wheatstone bridge [7], [8]. The indirect method is used to avoid this difficulty particularly by measuring some quantities of the dc motor itself. Dc motor parameters that are simpler to measure experimentally, like motor voltage, current, and shaft speed, are used to indirectly calculate the motor torque. This technology is unquestionably helpful in industrial settings because it avoids any mechanical impact on the actual installation. It is necessary to establish specific dc motor settings and characteristics before using