A Novel Hybrid Converter Proposed for Multi-MW Wind Generator for Offshore Applications

Abstract

Modern multi-MW wind generators have used multi-level converter structures as well as parallel configuration of a back to back three-level neutral point clamped (3L-NPC) converters to reduce the voltage and current stress on the semiconductor devices. These configurations of converters for offshore wind energy conversion applications results in high cost, low power density, and complex control circuitry. Moreover, a large number of power devices being used by former topologies results in an expensive and inefficient system. In this paper, a novel bi-directional three-phase hybrid converter that is based on a parallel combination of 3L-NPC and ‘n’ number of Vienna rectifiers have been proposed for multi-MW offshore wind generator applications. In this novel configuration, total power equally distributes by sharing of total reference current in each parallel-connected generator side power converter, which ensures the lower current stress on the semiconductor devices. Newly proposed topology has less number of power devices compared to the conventional configuration of parallel 3L-NPC converters, which results in cost-effective, compact in size, simple control circuitry, and good performance of the system. Three-phase electric grid is considered as a generator source for implementation of a proposed converter. The control scheme for a directly connected three-phase source with a novel configuration of a hybrid converter has been applied to ratify the equal power distribution in each parallel-connected module with good power factor and low current distortion. A parallel combination of a 3L-NPC and 3L-Vienna rectifier with a three-phase electric grid source has been simulated while using MATLAB and then implemented it on hardware. The simulation and experimental results ratify the performance and effectiveness of the proposed system.

Wind energy conversion technologies and engineering approaches to enhancing wind power generation: A review

“…As it was claimed in one of the recent system modeling-based studies, power generation through the implementation of this converter technology can be significantly enhanced by resulting in increased electricity production and reduced weight of the converter itself. NPC [ 26 , 117 , 118 ] More common for offshore wind power generation application than for onshore one The application of this power converter technology was limited for DFIG-based wind farms though it was proven to show promising candidacy for PMSG-based systems according to literature. Hence, critical consideration is required in this regard to possibly work on design advancement of this converter for its broader application in wind farms.…”

Pulse Pattern Optimization Based on Brute Force Method for Medium-Voltage Three-Level NPC Converter with Active Front End

“…A dynamic simulation of the proposed system configuration in Figure 2 was conducted in the simulation tool PLECS to verify the pulse patterns calculated with the BF method. The control structure for the SHE-PWM in a closed loop was used for controlling the DC link voltage as it is described in the literature [2,22,23]. Figure 9 illustrates the simulation schematic in the simulation tool PLECS.…”