Abstract : When paper is within its elastic range, the difference in linear velocity between its two ends is linearly related to the tension. Based on this, this paper explores a method for tension control using an AC motor, and presents a preliminary scheme for control algorithm, hardware structure, control scheme, and related parameter tuning. Keywords : linear velocity; radius; paper thickness; AC motor. In the two AC motor-driven rewinding machines we designed for a paper mill in Zhejiang, the scheme used was a closed-loop tension sensor plus a dedicated frequency converter and macro software for winding. This led to two problems: firstly, the cost of the dedicated software was too high and difficult to obtain; secondly, the installation of the tension sensor required high equipment processing quality, otherwise the noise interference caused by equipment vibration could easily drown out the effective signal, leading to sensor failure, and thus the actual working speed often did not reach the design speed. Based on this situation, this paper proposes an open-loop tension control scheme, utilizing the advantages of frequency converters in easy speed control and high control accuracy to achieve constant tension control through speed control. To this end, it is necessary to first explain the deformation of paper due to tension during the rewinding process. When a flexible web material is running under tension, its linear velocity is different at the two ends where the external force is applied, as shown in Figure 1. [b][align=center]For details, please click: Constant Tension Open-Loop Control Scheme for AC Rewinding Machines with Speed ​​Control[/align][/b]