Modular multilevel converters MMCs contain numerous IGBTs. The modeling of such converters for electromagnetic transient type, EMT type, simulations is complex. Detailed models used in MMC HVDC simulations may require very large computing times. Simplified and averaged models have been proposed in the past to overcome this problem. In this paper existing averaged and simplified models are improved in order to increase their range of applications. The models are compared and analyzed for different transient events on a MMC HVDC system.