Mansour Mohseni

Bio: Mansour Mohseni is an academic researcher from Curtin University. The author has contributed to research in topics: Wind power & AC power. The author has an hindex of 12, co-authored 38 publications receiving 1163 citations. Previous affiliations of Mansour Mohseni include University of Alberta & University College of Engineering.

Review of international grid codes for wind power integration: Diversity, technology and a case for global standard

Abstract: This paper presents a comprehensive study on the latest grid code regulations enforced by transmission system operators on large wind power plants (WPPs). First, the most common requirements included in the majority of international grid codes are compared; namely, low and high voltage ride-through capabilities, active and reactive power responses during and after faults, extended range of voltage–frequency variations, active power (frequency) control facility, and reactive power (voltage) regulation support. The paper also presents a discussion on the global harmonization of international grid codes as well as future trends expected in the regulations. Finally, the evolution of different wind generator technologies to fulfill various grid code requirements is investigated. The presented study will assist system operators to establish their connection requirements for the first time or to compare their existing regulations with other operators. It also enables wind turbine manufacturers and wind farm developers to obtain a more precise understanding from the latest international requirements imposed on modern wind farms.

Impacts of Symmetrical and Asymmetrical Voltage Sags on DFIG-Based Wind Turbines Considering Phase-Angle Jump, Voltage Recovery, and Sag Parameters

Abstract: This paper presents a new analysis into the impacts of various symmetrical and asymmetrical voltage sags on doubly fed induction generator (DFIG)-based wind turbines. Fault ride-through requirements are usually defined by the grid codes at the point of common coupling (PCC) of wind farms to the power network. However, depending on the network characteristics and constraints, the voltage sag conditions experienced at the wind generator terminals can be significantly different from the conditions at the PCC. Therefore, it is very important to identify the voltage sags that can practically affect the operation of wind generators. Extensive simulation studies are carried out in MATLAB/Simulink to investigate the transient overshoots and ripples that appear in the rotor current and dc-link voltage when the DFIG is subjected to various types of (a)symmetrical faults. For the first time, the impacts of phase-angle jump and operational constraints of circuit breakers are examined. Furthermore, the influences of sag parameters including type, initial point-on-wave instant, depth, and impedance angle are investigated. Complementary theoretical analyses are also presented to support the validity of observations made in the simulation studies.

Enhanced Hysteresis-Based Current Regulators in Vector Control of DFIG Wind Turbines

Abstract: This paper proposes enhanced hysteresis-based current regulators in the field-oriented vector control of doubly fed induction generator (DFIG) wind turbines. The proposed control scheme is synchronized with the virtual grid-flux space vector, readily extractable by a quadrature phase-locked loop (QPLL) system. Identical equidistant-band vector-based hysteresis current regulators (VBHCRs) are then used to control the output currents of the rotor-side and grid-side converters. The proposed hysteresis-based technique has excellent steady-state performance and reveals several advantages in comparison with the commonly used proportional-integral (PI) current regulator, including very fast transient response, simple control structure, and intrinsic robustness to the machine parameters variations. Moreover, the fixed hysteresis bands in VBHCRs are replaced with equidistant bands to limit the instantaneous variations of the switching frequency and reduce the maximum switching frequencies experienced in the converters. Extensive simulation studies are carried out for a 1.5 MW DFIG-based wind turbine to examine the operation of the proposed vector control scheme under changing wind speed and compare its transient and steady-state performances with the conventional PI current regulators.

A New Vector-Based Hysteresis Current Control Scheme for Three-Phase PWM Voltage-Source Inverters

Abstract: This paper presents a new vector-based hysteresis current controller (HCC) for three-phase pulsewidth modulation (PWM) voltage-source inverters (VSI). The HCC is intrinsically robust to the load parameters variations, exhibits very fast transient performance, and is suitable for simple implementations. Despite these advantages, the conventional HCC has a major drawback when applied to the three-phase PWM-VSI: interphases dependency leads to very high-switching frequencies in the inverter. This paper starts with a review on the vector-based HCCs reported in the literature to address this problem. Then, a new vector-based method is proposed using multilevel hysteresis comparators integrated with a switching table. The proposed method works with the inverter current vector represented in the stationary α- β frame and produces a coordinated switching pattern. The current error is kept inside a square tolerance region without significant increase in the complexity of the hardware implementation. Simulation results show that the proposed vector-based method can retain the advantages of the conventional HCC. However, the steady-state performance of the proposed current regulator is significantly improved by reducing the switching frequency and minimizing oscillations of the inverter current vector. The proposed current controller is finally compared with other reported vector-based methods and its advantages are illustrated.

Transient Control of DFIG-Based Wind Power Plants in Compliance With the Australian Grid Code

Abstract: Australian Grid Code has recently enforced stringent regulations on the transient response of large wind power plants (WPPs). The new grid code requires wind generators to ride-through severe low- and high-voltage conditions, provides reactive power support during the fault period, and exhibits fast power recovery after the supply voltage restoration. This paper proposes a new control scheme for doubly fed induction generator (DFIG)-based WPPs to fulfill these requirements in one inclusive approach. New design strategies for the outer power control loops of DFIG are suggested and their corresponding P-Q capability curves are rigorously studied. It is shown that safely overloaded converters can enhance the reactive power capability of DFIGs during the fault periods. Moreover, for the inner current control loops, the conventional PI current regulators are replaced with enhanced hysteresis-based current regulators. This current regulator, with very fast transient response, increases low- and high-voltage ride-through capabilities of the DFIG, as requested by the Australian Grid Code. Finally, time-domain simulation studies are conducted to evaluate the capability of the proposed control scheme to fulfill the Australian regulations and examine its positive impacts on the transient response of the adjacent fixed-speed WPP.

High-Power Wind Energy Conversion Systems: State-of-the-Art and Emerging Technologies

Abstract: This paper presents a comprehensive study on the state-of-the-art and emerging wind energy technologies from the electrical engineering perspective. In an attempt to decrease cost of energy, increase the wind energy conversion efficiency, reliability, power density, and comply with the stringent grid codes, the electric generators and power electronic converters have emerged in a rigorous manner. From the market based survey, the most successful generator-converter configurations are addressed along with few promising topologies available in the literature. The back-to-back connected converters, passive generator-side converters, converters for multiphase generators, and converters without intermediate dc-link are investigated for high-power wind energy conversion systems (WECS), and presented in low and medium voltage category. The onshore and offshore wind farm configurations are analyzed with respect to the series/parallel connection of wind turbine ac/dc output terminals, and high voltage ac/dc transmission. The fault-ride through compliance methods used in the induction and synchronous generator based WECS are also discussed. The past, present and future trends in megawatt WECS are reviewed in terms of mechanical and electrical technologies, integration to power systems, and control theory. The important survey results, and technical merits and demerits of various WECS electrical systems are summarized by tables. The list of current and future wind turbines are also provided along with technical details.

Overview of Control Systems for the Operation of DFIGs in Wind Energy Applications

Abstract: Doubly fed induction generators (DFIGs), often organized in wind parks, are the most important generators used for variable-speed wind energy generation. This paper reviews the control systems for the operation of DFIGs and brushless DFIGs in wind energy applications. Control systems for stand-alone operation, connection to balanced or unbalanced grids, sensorless control, and frequency support from DFIGs and low-voltage ride-through issues are discussed.

Fault Ride-Through of a DFIG Wind Turbine Using a Dynamic Voltage Restorer During Symmetrical and Asymmetrical Grid Faults

Abstract: The application of a dynamic voltage restorer (DVR) connected to a wind-turbine-driven doubly fed induction generator (DFIG) is investigated. The setup allows the wind turbine system an uninterruptible fault ride-through of voltage dips. The DVR can compensate the faulty line voltage, while the DFIG wind turbine can continue its nominal operation as demanded in actual grid codes. Simulation results for a 2 MW wind turbine and measurement results on a 22 kW laboratory setup are presented, especially for asymmetrical grid faults. They show the effectiveness of the DVR in comparison to the low-voltage ride-through of the DFIG using a crowbar that does not allow continuous reactive power production.

Review of international grid codes for wind power integration: Diversity, technology and a case for global standard

Abstract: This paper presents a comprehensive study on the latest grid code regulations enforced by transmission system operators on large wind power plants (WPPs). First, the most common requirements included in the majority of international grid codes are compared; namely, low and high voltage ride-through capabilities, active and reactive power responses during and after faults, extended range of voltage–frequency variations, active power (frequency) control facility, and reactive power (voltage) regulation support. The paper also presents a discussion on the global harmonization of international grid codes as well as future trends expected in the regulations. Finally, the evolution of different wind generator technologies to fulfill various grid code requirements is investigated. The presented study will assist system operators to establish their connection requirements for the first time or to compare their existing regulations with other operators. It also enables wind turbine manufacturers and wind farm developers to obtain a more precise understanding from the latest international requirements imposed on modern wind farms.