Modified Lyapunov-Based Model Predictive Direct Power Control of an AC-DC Converter with Power Ripple Reduction

This paper presents a modified Model Predictive- Direct Power Control scheme (MP-DPC) for an AC-DC power converter with the help of Lyapunov constraints. Conventional MP-DPC has the disadvantage of using a PI controller, which makes the responses sluggish and has large power ripples. The Lyapunov function has an added advantage of further improving the stability with the help of inequality constraints over a bounded region by finding a local optimal point rather than a global one. The disturbance vector used in the Lyapunov function is responsible for selecting the best possible future switching state, which is the reference voltage vector for space vector (SV-PWM). The proposed scheme achieves a better dynamic response at the output DC voltage along with reduced ripples in both real and reactive power. Simulation results are presented to verify that the proposed Lyapunov based MP-DPC scheme (which has no PI) has an improved dynamic response and lower power ripple compared to the conventional MP-DPC (with PI).