Modulated MPC for Arm Inductor-less MVDC MMC with Reduced Computational Burden

TL;DR

This paper introduces a novel modulated model predictive controller for inductor-less MVDC MMCs, reducing computational burden and enabling efficient transient and steady-state control for solid-state transformers.

Contribution

It presents a closed-form solution for the control problem, eliminating the need for inductors and tuned PI controllers, with a new circulating energy compensator for lower sampling speeds.

Findings

Achieves inductor-less current control with reduced computation.

Demonstrates effective transient power flow and steady-state energy control.

Validates performance through simulation and experiments.

Abstract

A modulated model predictive controller is designed for an inductor-less modular multilevel converter targeting an MVDC solid-state transformer application. The underlying optimization problem is formulated such that a unique closed-form solution is derived from a highly accurate dynamic system model, which significantly reduces computation time. Unlike other closed-form methods, the proposed controller achieves inductor-less current control, has a reduced sampling speed enabled by a novel model-based circulating energy compensator, and does not require tuned PI controllers to generate current references. Simulation and experimental results demonstrate that the proposed controller achieves transient power flow control and steady state circulating energy control despite the low system inertia.