Rotary assembly platforms are used in several automation applications, such as box-fill systems. In modern automatic machines, several actuators may be mounted on the rotating platform, but this architecture raises the problem of their feeding. The solution developed in this paper consists in adopting a LLC resonant converter that uses the leakage and magnetizing inductances of a rotary transformer as inductors of the resonant network. Furthermore, since the output voltage on the rotating platform cannot be directly measured, a sensorless control scheme has been developed to improve load regulation. Experimental results are provided to show the effectiveness of the converter and its control scheme.