The present invention relates to a switched power converter system (1), comprising at least a first power converter (2) and a second power converter (3). Each power converter (2, 3) has a corresponding input terminal (4a, 5a) and output terminal (4b, 5b), where each power converter (2, 3) comprises a corresponding switch arrangement (6, 7). The system further comprises a control unit (8) that at least at start-up is connected to each power converter (2, 3) in the system (1) and arranged to control each switch arrangement (6, 7) by means of spread spectrum modulation, such that cross correlation between the conducted or radiated emissions of the switch arrangements (6, 7) is avoided.