Energy saving by reducing motor rating of Sucker-Rod Pump systems

Abstract Energy industry can make significant savings by reducing electric motors ratings of the popular Sucker-Rod Pump (SRP) systems. This can be achieved by application of robust controllers, which are fully integrated with the SRP systems. In this work we have developed, modelled and analysed such integrated systems, specifically by examining two control schemes with open- and closed-loop controllers. The open loop scheme employs a genetic algorithm optimizing frequency in order to minimize fluctuations in a motor output power. This approach results in reducing the peak torque and consequently decreases the required motor rating by 20%. However, the scheme relies on a complex model of this electromechanical system, and it is computationally expensive. The second proposed scheme with a closed-loop control, the first of its kind for the SRP systems, is much faster and robust. It allows to reduce the motor rating by further 30% of that required in the open-loop scheme, which can save $246 M through choosing smaller motors and $39 M per year by reducing motor inner loss.