Scalable Optimal Control Allocation: Linear and Quadratic Programming Methods Applied to Active Capacitor Balancing in Modular Multilevel Converters

Submodule Temperature Regulation and Balancing in Modular Multilevel Converters

In modular multilevel converters (MMCs), tem5 perature control of semiconductor devices in the submod6 ules (SMs) is a key factor for the safe and reliable opera7 tion. Under normal operation, significant temperature differ8 ences can exist between SMs due to, for example, aging of 9 semiconductor modules and module parameter mismatch. 10 This paper presents a method for achieving SM thermal ba...

Modular Multilevel Converters: Control and Applications

This review article is mainly oriented to the control and applications of modular multilevel converters (MMC). The main topologies of the switching modules are presented, for normal operation and for the elimination of DC faults. Methods to keep the capacitor voltage balanced are included. The voltage and current modulators, that are the most internal loops of control, are detailed. Voltage con...

Optimal Linear Quadratic Control

Linear Quadratic Optimal Control

In previous lectures, we discussed the design of state feedback controllers using using eigenvalue (pole) placement algorithms. For single input systems, given a set of desired eigenvalues, the feedback gain to achieve this is unique (as long as the system is controllable). For multi-input systems, the feedback gain is not unique, so there is additional design freedom. How does one utilize this...

Capacitor Voltage Monitoring in Modular Multilevel Converter

A Modular Multilevel Converter (MMC) is an attractive solution for power conversion without transformers. As MMC consists of cascade connections and floating dc capacitors, it requires continuous voltage monitoring. An adaptive observer design has been presented to estimate the capacitor voltages from the measurement of arm currents. This work introduces a capacitance value of the cell capacito...