Modeling and control for non-regenerative three-level boost rectifier considering DC-link voltage balance

In this paper, a new average d-q model for the non-regenerative three-level boost rectifier is proposed. The state space analysis is first carried out and an optimal zero sequence injection is found from the perspective of DC-link voltage balance or neutral point control. By utilizing this zero component the equilibrium point of the neutral point voltage is established and then the behavior of the voltage balance can be modeled in the d-q coordinate. Based on the proposed model, a controller with carrier-based implementation is developed, which features great simplicity and good DC-link voltage balance regulation. Both simulation and experimental results verified the feasibility of the proposed model and control approach.