High-Performance Control of Switched Reluctance Motors

A general high bandwidth, low ripple, instantaneous torque control strategy with a variable field-angle for extended constant-power speed range is presented. The strategy is based on the SR motor's electromagnetic characteristics measured at the motor terminals and is the nearest functional equivalent to AC vector control for this type of machine. Low torque ripple and high bandwidth are achieved over a wide range of speeds and a constant power range of 3:1. The proposed controller, which is applicable to most SR motors, is found to reduce the torque ripple by a factor of 5 in comparison with conventional square-wave current operation, and has been operated over a speed range of 1:6000

Modular Multilevel Converter Modelling, Control and Analysis under Grid Frequency Deviations

A tool for component sizing for MMCs has been developed and tested through simulations in PLECS. The steady-state behaviour under grid frequency deviations — interesting for offshore wind farm connections — has been analysed, providing insights in MMC characteristics and further testing the proposed tool

Var reserve concept applied to a wind power plant

wind power plants. This paper proposes two different VAr reserve control strategies for a wind power plant. The amount of dynamic VAr available most of the operation time, makes the wind power plant (WPP) a good candidate to include a VAr reserve management system. Two different ways of implementing a VAr management system are proposed and analyzed.Peer ReviewedPostprint (author’s final draft

Application of over-current relay in offshore wind power plant grid with VSC-HVDC connection

This paper presents the setting and coordination of over-current relays in an offshore wind power plant (WPP) grid connected only to the power electronic converters with limited fault current capability. The limited fault current injection capability of the converters has been considered as a hindrance for the relay setting. This characteristic can be utilized to develop a deterministic picture of the radial grid network and then the relays settings could be applied. The relay coordination has been demonstrated through an implementation in the Real Time Digital Simulator (RTDS) platform. The setting of relay parameters based upon maximum nominal currents is explained and the consequences are investigated

Application of over-current relay in offshore wind power plant grid with VSC-HVDC connection

This paper presents the setting and coordination of over-current relays in an offshore wind power plant (WPP) grid connected only to the power electronic converters with limited fault current capability. The limited fault current injection capability of the converters has been considered as a hindrance for the relay setting. This characteristic can be utilized to develop a deterministic picture of the radial grid network and then the relays settings could be applied. The relay coordination has been demonstrated through an implementation in the Real Time Digital Simulator (RTDS) platform. The setting of relay parameters based upon maximum nominal currents is explained and the consequences are investigated.Postprint (author’s final draft

Application of over-current relay in offshore wind power plant grid with VSC-HVDC connection

This paper presents the setting and coordination of over-current relays in an offshore wind power plant (WPP) grid connected only to the power electronic converters with limited fault current capability. The limited fault current injection capability of the converters has been considered as a hindrance for the relay setting. This characteristic can be utilized to develop a deterministic picture of the radial grid network and then the relays settings could be applied. The relay coordination has been demonstrated through an implementation in the Real Time Digital Simulator (RTDS) platform. The setting of relay parameters based upon maximum nominal currents is explained and the consequences are investigated

Wind power plant control: an overview

Recent developments in wind turbine technology go towards installation of larger Wind Power Plants (WPPs). Therefore, power system operators have been challenged by the WPP penetration impacts in order to maintain reliabillity and stability of the power system. The revised grid codes have concentrated on the WPP connection point and as a result a WPP is considered as a single power plant. Nevertheless, compared to conventional power plants, WPPs have different inherent features such as converter-based grid interface technology, internal electrical layout, and asynchronous operation of turbines. Talking these into account, a WPP controller is the key factor in order to satisfy the grid code requirements. This paper presents a comprehensive overview of various WPP controller strategies comprising active power, reactive power, voltage, frequency, and emulated inertia control. The WPP control architecture composed of WPP control level and wind turbine control level is also discussed considering the hierearchy and coordination of these levels.Postprint (published version