The paper suggests a control system of a three-phase power factor corrector. The study of the control system operation is carried out and the expressions for calculating the permissible values of error amplifier factors are obtained. The influence of the error amplifier parameters on phase current quality is investigated. The dependence of total harmonic distortion input current on a combination of error amplifier parameters is obtained at a given value of power factor. The conditions under which the total harmonic distortion input current has the minimum value are found out. This article is of interest to power electronics engineers, who are aimed at developing a three-phase power factor corrector.