Duty Cycle Optimization for Constant Switching Frequency in 3-Phase, 2-Level PWM Rectifiers, Using Modified Modulated Predictive Control

In order to improve the steady-state performance of the finite control set model predictive control (FCS-MPC), this paper proposes a simplified modulated predictive current control scheme for a three-phase two-level PWM rectifier.In the proposed scheme, the optimal vector is evaluated initially similarly to the conventional finite control set model predictive control (FCS-MPC).Later, an additional stage is included to compute the duty cycle of the optimal voltage vector obtained from stage 1 by using the simplified relationship between the cost-function values and the duty cycle.Compared to the prior art the proposed approach can effectively improve the THD of the input current with less complexity.The proposed approach retains the fast dynamic response of the FCS-MPC with an improved steady-state performance.In addition, the fixed switching frequency operation is also obtained.