Cascaded bridgeless totem-pole multilevel converter with model predictive control for 400 V dc-powered data centers

A cascaded bridgeless totem-pole multilevel converter and its model predictive control (MPC) are proposed for the power interface of 400 V dc-powered data centers. Wide bandgap devices such as gallium nitride (GaN) or silicon carbide (SiC) MOSFETs with very low reverse recovery charge are utilized in the proposed totem-pole converter to reduce the switching loss. DC bus voltage error can be effectively mitigated by adopting the proposed MPC strategy when compared with a conventional proportional-integral (PI) control; the proposed MPC also exhibits smaller overshoot and much faster response when the load changes, and can operate at lower switching frequencies, thus further reducing switching losses. Furthermore, it is easier to balance the dc-bus voltages in each module using the proposed MPC control. The simulation and hardware-in-loop test results of conventional PI and proposed MPC controllers are presented to validate the effectiveness of the proposed converter and its control algorithm.