In this paper, a new optimal control algorithm for AC to DC converter is proposed. The control algorithm is based on the PSO algorithm and PID controller. The PID controller’s gains are optimally tuned by PSO algorithm, hence, the optimal control strategy. Here, the topology of the AC to DC power converter is modeled first. Based on the modeled topology, the proposed optimal control algorithm is designed such that there is no error between the actual and reference value of the instantaneous input power. Since, input power reference is computed from the fraction of actual input voltage and its peak value, it allows the input current follow the input voltage such that power factor of the converter remains near unity. The performance of the proposed optimal control algorithm for AC to DC converter is analyzed in terms of power factor correction and efficiency. The validation of the proposed power converter’s topology model and its proposed optimal PSO-PID control algorithm is performed on MATLAB working platform. Simulation results are examined. © 2015 Elsevier B.V., All rights reserved.