A new average-value model of a rectifier circuit in a synchronous-machine-fed rectifier system is set forth. In the proposed approach, a proper state model of the synchronous machine in the qd-rotor reference frame is used, whereas the rectifier/dc-link dynamics are represented using a suitable proper transfer function and a set of nonlinear algebraic functions that are obtained from the detailed model using numerical averaging. The new model is compared to a detailed simulation as well as to measured data and is shown to be very accurate in predicting the large-signal time-domain transients as well as small-signal frequency-domain characteristics.