Internal Model Control of DFIG Based Micro Wind Energy Conversion System

Sourav Bose,S.P.Singh 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

Amongst the alternative renewable energy sources, the micro wind energy conversion system promises of reliability, cost effectiveness in rural areas where grid power is unavailable for electrification calling for sustainable development. Numerous studies on the control schemes are being conducted to generate electrical energy from the available wind energy using doubly fed induction generator (DFIG). In this paper, the internal model control (IMC) method is used to control rotor currents, speed and stator reactive power of DFIG based wind energy conversion system(WECS). The result is stator flux reference frame proportional integral (PI) or PI-type controllers, and the parameters of the controllers are directly expressed in certain parameters of the DFIG and the desired bandwidth of the close loop. This Process eliminates the trial and error steps to tune the PI controllers during vector control of DFIG. A 1 hp wound type induction generator coupled with 1 kW dc motor is used for the experiment. Performance of the propose single VSC based DFIG has been analyzed under different conditions.

Hierarchical Voltage Control of a Wind Power Plant Using the Adaptive I<SUB>Q</SUB>-V Characteristic of a Doubly-Fed Induction Generator

Jinho Kim,Geon Park,Jul-Ki Seok,Byongjun Lee,Yong Cheol Kang 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

Because wind generators (WGs) in a wind power plant (WPP) produce different active powers due to wake effects, the reactive power capability of each WG is different. This paper proposes a hierarchical voltage control scheme for a WPP that uses a WPP controller and WG controller. In the proposed scheme, the WPP controller determines a voltage error signal by using a PI controller and sends it to a doubly-fed induction generator (DFIG). Based on the reactive current-voltage (IQ-V) characteristic of a DFIG, the DFIG injects an appropriate reactive power corresponding to the voltage error signal. To enhance the voltage recovery capability, the gains of the IQ-V characteristic of a DFIG are modified depending on its reactive current capability so that a DFIG with greater reactive current capability may inject more reactive power. The proposed scheme enables the WPP to recover the voltage at the point of common coupling (PCC) to the nominal value within a short time after a disturbance by using the adaptive IQ-V characteristics of a DFIG. The performance of the proposed scheme was investigated for a 100 MW WPP consisting of 20 units of 5 MW DFIGs for small and larger disturbances. The results show the proposed scheme successfully recovers the PCC voltage within a short time after a disturbance.

DFIG 풍력터빈의 계통 저전압 발생 시 빠른 과도상태자속 감쇄를 위한 컨버터 제어 방법

김태형(Tae-Hyeong Kim),송승호(Seung-Ho Song) 대한전기학회 2020 전기학회논문지 Vol.69 No.1

The high penetration of large power capacity of wind power plants connected to the grid directly can lead to serious problem of power system stability. Wind turbines should control active and reactive power according to the requirements of grid code and should stay connected to the grid during grid voltage disturbance. Doubly fed induction generator(DFIG) provides the advantage of variable speed operation and control of rated active and reactive power using a small rated power of converter approximately 30% power capacity of the generator. But the main drawback of this type of wind turbine is large sensitivity to the grid voltage disturbance, because the stator of a DFIG is directly connected to the grid. In this paper, based on theoretical study, the dynamic behavior of DFIG under grid voltage dips is analyzed and a control method of rotor current injection is proposed for the fast decrease of the transient natural stator flux. The proposed control strategy focuses on the mitigation of the transient natural stator flux for the reduction of high voltage on rotor-side and the injection of the reactive current for grid voltage support simultaneouly. For the verification of the proposed control strategy, a complete simulation model for 2MW DFIG is implemented and its performance is extensively examined using PSCAD.

Hierarchical Voltage Control of a Wind Power Plant Using the Adaptive I_Q-V Characteristic of a Doubly-Fed Induction Generator

Kim, Jinho,Park, Geon,Seok, Jul-Ki,Lee, Byongjun,Kang, Yong Cheol The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

Because wind generators (WGs) in a wind power plant (WPP) produce different active powers due to wake effects, the reactive power capability of each WG is different. This paper proposes a hierarchical voltage control scheme for a WPP that uses a WPP controller and WG controller. In the proposed scheme, the WPP controller determines a voltage error signal by using a PI controller and sends it to a doubly-fed induction generator (DFIG). Based on the reactive current-voltage ($I_Q-V$) characteristic of a DFIG, the DFIG injects an appropriate reactive power corresponding to the voltage error signal. To enhance the voltage recovery capability, the gains of the $I_Q-V$ characteristic of a DFIG are modified depending on its reactive current capability so that a DFIG with greater reactive current capability may inject more reactive power. The proposed scheme enables the WPP to recover the voltage at the point of common coupling (PCC) to the nominal value within a short time after a disturbance by using the adaptive $I_Q-V$ characteristics of a DFIG. The performance of the proposed scheme was investigated for a 100 MW WPP consisting of 20 units of 5 MW DFIGs for small and larger disturbances. The results show the proposed scheme successfully recovers the PCC voltage within a short time after a disturbance.

Comparative Study between Two Protection Schemes for DFIG-based Wind Generator Fault Ride Through

Okedu, K.E.,Muyeen, S.M.,Takahashi, R.,Tamura, J. Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1

Fixed speed wind turbine generators system that uses induction generator as a wind generator has the stability problem similar to a synchronous generator. On the other hand, doubly fed induction generator (DFIG) has the flexibility to control its real and reactive powers independently while being operated in variable speed mode. This paper focuses on a scheme where IG is stabilized by using DFIG during grid fault. In that case, DFIG will be heavily stressed and a remedy should be found out to protect the frequency converter as well as to allow the independent control of real and reactive powers without loosing the synchronism. For that purpose, a crowbar protection switch or DC-link protecting device can be considered. This paper presents a comparative study between two protective schemes, a crowbar circuit connected across the rotor of the DFIG and a protective device connected in the DC-link circuit of the frequency converter. Simulation analysis by using PSCAD/EMTDC shows that both schemes could effectively protect the DFIG, but the latter scheme is superior to the former, because of less circuitry involved.

최대 전압 강하에 비례하는 무효전류 공급 루프를 이용한 DFIG 풍력단지의 계층전압제어

박건(Geon Park),김진호(Jinho Kim),강용철(Yong Cheol Kang) 대한전기학회 2016 전기학회논문지 Vol.65 No.8

In a power grid that has a high wind power penetration, the fast voltage support of a wind power plant (WPP) during the grid fault is required to stabilize the grid voltage. This paper proposes a voltage control scheme of a doubly-fed induction generator (DFIG)-based WPP that can promptly support the voltage of the point of common coupling (PCC) of a WPP during the grid fault. In the proposed scheme, the WPP and DFIG controllers operate in a voltage control mode. The DFIG controller employs two control loops: a maximum voltage dip-dependent reactive current injection loop and a reactive power to voltage loop. The former injects the reactive power in proportion to the maximum voltage dip; the latter injects the reactive power in proportion to the available reactive power capability of a DFIG. The former improves the performance of the conventional voltage control scheme, which uses the latter only, by increasing the reactive power as a function of the maximum voltage dip. The performance of the proposed scheme was investigated for a 100-㎿ WPP consisting of 20 units of a 5-㎿ DFIG under various grid fault scenarios using an EMTP-RV simulator. The simulation results indicate that the proposed scheme promptly supports the PCC voltage during the fault under various fault conditions by increasing the reactive current with the maximum voltage dip.

Hierarchical Voltage Control of a Wind Power Plant Using the Adaptive IQ-V Characteristic of a Doubly-Fed Induction Generator

김진호,박건,이병준,석줄기,강용철 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

Because wind generators (WGs) in a wind power plant (WPP) produce different activepowers due to wake effects, the reactive power capability of each WG is different. This paper proposesa hierarchical voltage control scheme for a WPP that uses a WPP controller and WG controller. In theproposed scheme, the WPP controller determines a voltage error signal by using a PI controller andsends it to a doubly-fed induction generator (DFIG). Based on the reactive current-voltage (IQ-V)characteristic of a DFIG, the DFIG injects an appropriate reactive power corresponding to the voltageerror signal. To enhance the voltage recovery capability, the gains of the IQ-V characteristic of a DFIGare modified depending on its reactive current capability so that a DFIG with greater reactive currentcapability may inject more reactive power. The proposed scheme enables the WPP to recover thevoltage at the point of common coupling (PCC) to the nominal value within a short time after adisturbance by using the adaptive IQ-V characteristics of a DFIG. The performance of the proposedscheme was investigated for a 100 MW WPP consisting of 20 units of 5 MW DFIGs for small andlarger disturbances. The results show the proposed scheme successfully recovers the PCC voltagewithin a short time after a disturbance.

Adaptive Neural PLL for Grid-connected DFIG Synchronization

Ali Bechouche,Djaffar Ould Abdeslam,Tahar Otmane-Cherif,Hamid Seddiki 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3

In this paper, an adaptive neural phase-locked loop (AN-PLL) based on adaptive linear neuron is proposed for grid-connected doubly fed induction generator (DFIG) synchronization. The proposed AN-PLL architecture comprises three stages, namely, the frequency of polluted and distorted grid voltages is tracked online; the grid voltages are filtered, and the voltage vector amplitude is detected; the phase angle is estimated. First, the AN-PLL architecture is implemented and applied to a real three-phase power supply. Thereafter, the performances and robustness of the new AN-PLL under voltage sag and two-phase faults are compared with those of conventional PLL. Finally, an application of the suggested AN-PLL in the grid-connected DFIG-decoupled control strategy is conducted. Experimental results prove the good performances of the new AN-PLL in grid-connected DFIG synchronization.

Augmentation of Wind Farms Ride Through by DFIG-based Variable Speed Wind Generators

Okedu, K.E.,Muyeen, S.M.,Takahashi, R.,Tamura, J. Journal of International Conference on Electrical 2012 Journal of international Conference on Electrical Vol.1 No.1

Wind farm grid codes require wind generators to ride through voltage sags, which means that normal power production should be re-initiated once the nominal grid voltage has been recovered. Doubly Fed Induction Generator (DFIG) based wind farm is gaining popularity these days because of its inherent advantages like variable speed operation and independent controllability of active and reactive power over conventional Induction Generator (IG). This paper proposes a new control strategy using DFIGs for stabilizing a wind farm composed of DFIGs and IGs. Simulation analysis by using PSCAD/EMTDC shows that the DFIGs can effectively stabilize the IGs and hence the entire wind farm through the proposed control scheme by providing sufficient reactive power to the system.

연계선로의 조건 변화에 따른 DFIG와 FSIG 풍력발전시스템의 운전특성 비교

노경수(Kyoung-Soo Ro),김태호(Tae-Ho Kim) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.9

This paper analyzes the steady-state output characteristics of variable-speed wind turbine systems using doubly-fed induction generators(DFIG) compared with fixed-speed induction generator(FSIG) wind turbine systems. It also presents simulations of a grid-connected wind turbine generation system for dynamics analysis on MATLAB/Simulink and compares the responses between DFIG and FSIG wind turbine systems with respect to wind speed variation, impedance changes and X/R ratio changes of interconnecting circuits. Simulation results show the variation of generator's active output, terminal voltage and fault currents at the interconnecting point. Case studies demonstrate that DFIG wind turbine systems illustrate better performance to 3-phase fault than FSIG's.