Modular Multilevel Converter with Sensorless Diode-Clamped Balancing through Level-Adjusted Phase-Shifted Modulation

Cascaded H-bridge and modular multilevel converters (MMC) are on the rise with emerging applications in renewable energy generation, energy storage, and electric motor drives. However, their well-known advantages come at the price of complicated balancing, high-bandwidth isolated monitoring, and numerous sensors that can prevent MMCs from expanding into highly cost driven markets. Therefore, an obvious trend in research is developing control and topologies that depend less on measurements and benefit from simpler control. Diode-clamped topologies are considered among the more applicable solutions. The main problem with a diode-clamped topology is that it can only balance the module voltages of a string in one direction; therefore, it cannot provide a completely balanced operation. This paper proposes an effective balancing technique for the diode-clamped topology. The proposed solution exploits the dc component of the arm current by introducing a symmetrically level-adjusted phase-shifted modulation scheme, and ensures the balancing current flow is always in the correct direction. The main advantages of this method are sensorless operation, no added computation and control effort, and low overall cost. Analysis and detailed simulations provide insight into the operation of the system as well as the new balancing technique and the experimental results confirm the provided discussions

Dual-Port Dynamically Reconfigurable Battery with Semi-Controlled and Fully-Controlled Outputs

Modular multilevel converters (MMC) and cascaded H-bridge (CHB) converters are an established concept in ultra-high voltage systems. In combination with batteries, these circuits allow dynamically changing the series or parallel configuration of subportions of the battery as so-called modular battery integrated converters or reconfigurable batteries, and are being discussed for grid-storage and electromobility applications. A large body of research focuses on such circuits for supplying a single load, such as a motor for electric drives. Modularity, failure tolerance, less dependence on the weakest element of a battery pack, higher controllability, and better efficiency are the main incentives behind this pursuit. However, most studies neglect the auxiliary loads which require isolation from the high-voltage battery. This paper proposes a simple topology and controller that can fork off a second (galvanically isolated) output of a reconfigurable dc battery. The proposed system provides a nonisolated semicontrolled port for the dc link to maintain the operating point of the main inverter(s) close to optimal, while fully controlling an isolated output for the auxiliaries per the safety regulations. The proposed system does not require additional active switches for the auxiliary port and can operate with a wide range of voltages. Simulation and experiments verify the developed analysis.Comment: All Rights reserved. This work has been submitted for publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Hacking encrypted frequency-varying wireless power : cyber-security of dynamic charging

202407 bcchAccepted ManuscriptRGCPublishedGreen (AAM