High Efficient Maximum Power Point Tracking for Multiple Solar Strings with GaN-Based HiLEM Circuit

This paper discusses the potentials of string based Maximum Power Point Tracking (MPPT) in ground-mounted solar power plants using the HiLEM topology. First, the functionality of the HiLEM circuit is described, then the planned setup with the HiLEM topology is presented. Finally, the operating principle is illustrated by a simulated shading scenario

A 60 kW Power Hardware-in-the-Loop Test Bench for grid emulation based on a Series Hybrid Cascaded H-Bridge Converter

In this paper the requirements for a Power Hardware-In-the-Loop (PHIL) system for the emulation of grids and grid faults are discussed. Solutions for all parts of the PHIL system – the power electronics, the signal processing system and the software structure – are presented. Subsequently, an analysis of the accuracy, bandwidth and stability of the PHIL testbench is done and the effects of different interface algorithms are shown. Concluding, measurement results of emulated highly dynamic grid faults such as voltage dips and spikes, distorted grids and weak grid situations are shown, which prove the performance of the PHIL system

A Highly Integrated 25-Level Cascaded H-Bridge Active Filter for the Mitigation of High Order Current Harmonics

The increasing share of power electronics in the conversion and distribution of electrical energy represents a novel challenge for energy quality and supply stability. It is to be expected that high-frequency current harmonics will increase significantly with the number of grid-connected power converters. To reduce the associated disadvantages, this paper presents a 25-Level Cascaded H-Bridge Active Filter for mitigating converter-induced current harmonics in the kilohertz range.~Compared to conventional active filters, the proposed use of a voltage-source active filter does not require high control bandwidth, tuning to specific frequencies or measurement and tracking of high frequency currents.~The highly integrated design on printed circuit boards allows a high number of voltage levels and a high power density at small additional effort and costs. A 12 kVA-demonstrator is used to mitigate the switching frequency current harmonics of a grid-connected two-level converter, verifying the effectiveness of the active filter configuration

Hybrid Implementation of Cascade Control for GaN-Based Modular Multilevel Converter for Low-Voltage Grid

A hybrid control system implementation for a Modular Multilevel Converter (MMC) prototype is presented in this paper. The cascade control using an ARM processor for the energy controller and a field programmable gate array (FPGA) for the current controllers, allows the GaN semiconductors to generate an output current with an effective ripple frequency of 200 kHz. The MMC system model and the partitioning of the cascade control are shown. With its dynamic current limit, implemented in the FPGA, the MMC is able to provide AC currents above the nominal current. Finally, prototype measurements of an emulated grid fault are shown

A standardized and modular power electronics platform for academic research on advanced grid-connected converter control and microgrids

This paper introduces a multifunctional converter platform rated at 30kW. Individual units allow research on advanced grid-connected converter control, while their interconnection enables isolated microgrid investigations. The standardized and modular design allows simple reconfiguration of the system for different setups, for which multiple measurements are presented

Cascaded H-Bridge based Parallel Hybrid Converter - A novel Topology for perfectly sinusoidal high power Voltage Sources

The demand for high voltage, high power, high precision and high dynamic 3AC-voltage sources is increasing constantly. One application that gets more and more important in recent years and demands such voltage sources is e.g. Power-Hardware-in-the-Loop (PHIL) Emulation. In this paper a new power converter topology called “Parallel Hybrid Converter” or PHC is presented and a corresponding control scheme is derived. This new converter has a terminal behavior similar to a MMC or MMPMC but compared to them the PHC features significantly reduced costs and a significantly improved power density