Battery Energy Storage System for Variable Speed Driven PMSG for Wind Energy Conversion System

ABSTRACT:

There are many loads such as remote villages, islands, etc. that are located far away from the main grid. These loads require stand-alone generating system, which can provide constant voltage and frequency for local electrification. Locally available wind power can be used in such off-grid systems. As the wind speed is variable, an AC-DC-AC conversion system is required to convert variable voltage and variable frequency power generation to constant voltage and constant frequency source. Further, as the wind power as well as load is variable there is a need of energy storage device that take care of the load mismatch. In this paper, a standalone wind energy conversion system (WECS) using a variable speed permanent magnet synchronous generator (PMSG) is proposed with a battery energy storage system.

KEYWORDS:

1.      Wind energy conversion system

2.      Isolated system

3.      BESS

4.      Permanent magnet synchronous generator

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig.1 PMSG with PWM rectifier with battery for storing the extra wind energy

EXPECTED SIMULATION RESULTS:

Fig.2. Variation of wind speed, load voltages, load currents, generator power, battery power, load power battery current and DC link voltage.

CONCLUSION:

The isolated operation of wind energy conversion system requires AC-DC-AC interface with the capability of converting variable voltage variable frequency to constant voltage constant frequency source. In addition the power balancing has to be done with some energy storage system, According to the proposed topology, battery energy storage system provides power balance between the generated power and the load. The power mismatch is absorbed by the BESS.

REFERENCES:

[1] Bhim Singh and Gaurav Kumar Kasal, “Solid-State Voltage and Frequency Controller for a stand alone wind power generating system,” IEEE Trans. Power Electronics, vol. 23, no.3, pp.1170–1177, 2008.

[2] Bhim Singh and Gaurav Kumar Kasal, “Voltage and Frequency Controller for a 3-Phase 4-Wire Autonomous Wind Energy Conversion System” accepted for publication in IEEE Trans. on Energy Conversion.

[3] Ghosh and G. Ledwich, Power Quality Enhancement Using Custom Power Devices. Kulwer Academic, 2002.

[4] Gipe, P. Wind power’, Chelsea Green Publishing Company, Post Mills, Vermount, USA,1995.

[5] Rai, G.D. (2000) ‘Non conventional energy sources’, Khanna Publishers, 4th Edition, New Delhi (India)

An Energy Management Scheme with Power Limit Capability and an Adaptive Maximum Power Point Tracking for Small Standalone PMSG Wind Energy Systems

ABSTRACT:

Due to its high energy generation capability and minimal environmental impact, wind energy is an elegant solution to the growing global energy demand. However, frequent atmospheric changes make it difficult to effectively harness the energy in the wind because maximum power extraction occurs at a different operating point for each wind condition. This paper proposes a parameter independent intelligent power management controller that consists of a slope-assisted maximum power point tracking (MPPT) algorithm and a power limit search (PLS) algorithm for small standalone wind energy systems with permanent synchronous generators. Unlike the parameter independent perturb & observe (P&O) algorithms, the proposed slope-assisted MPPT algorithm preempts logical errors attributed to wind fluctuations by detecting and identifying atmospheric changes. The controller’s PLS is able to minimize the production of surplus energy to minimize the heat dissipation requirements of the energy release mechanism by cooperating with the state observer and using the slope parameter to seek the operating points that result in the desired power rather than the maximum power. The functionality of the proposed energy management control scheme for wind energy systems is verified through simulation results and experimental results.

KEYWORDS:

1.      Wind energy

2.       Maximum power point tracking

3.      Energy  management

4.      Power electronics

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig 1 System diagram with the proposed management control algorithm

EXPECTED SIMULATION RESULTS:

Fig 2 Performance of the standard fixed-step size P&O algorithm (average power captured = 1066 W).

Fig 3 Performance of the standard variable-step size P&O algorithm (average power captured = 1106 W).

Fig 4 Performance of the slope-assisted MPPT algorithm (1238 W).

Fig 5 Power coefficient performance of the fixed-step size P&O, variable step size P&O, and the slope assist MPPT (comparison performed under atmospheric identical conditions as depicted in Fig.20).

CONCLUSION:

In this paper, an intelligent parameter-independent power management controller has been presented for standalone offgrid small wind energy systems. With the state observer presiding over the slope-assisted MPPT and the PLS in the proposed controller, the convergence times to the desired operating points is reduced and the logical errors are minimized by identifying the changes in wind conditions. Being applicable for both grid-connected and standalone wind systems, the slope assist MPPT increases a wind system’s MPP search efficiency and enables the wind system to actively adapt to its changing behavior and wind conditions. The PLS algorithm was designed to complement the slope assist MPPT for standalone wind systems that have limited energy storage and use energy dissipation mechanisms to disperse surplus energy. Rather than focusing on capturing maximum power, the power limit search focuses on reducing the size and heat requirements of the energy dissipation mechanism by minimizing surplus power generation as desired. The operating principles of the proposed PLS and MPPT control techniques have been discussed in this paper. Simulation results on a 3kW system and experimental results on a proof-of-concept prototype with a wind turbine emulator have been provided to highlight the merits of this work.

REFERENCES:

[1] Global Wind Energy Council, "Global Wind Report - Anual Market Update 2012," 2013.

[2] Global Wind Energy Council, "Global Wind 2011 Report," 2012.

[3] Canadian Wind Energy Association, "Canadian Wind Energy Association," [Online]. Available: www.canwea.ca.

[4] Q. Wang and L. Chang, "An Intelligent Maximum Power Extraction Algorithm for Inverter-Based Variable Speed Wind Turbine Systems," IEEE Transactions on Power Electronics, vol. 1, September 2004, pp. 1242-1249.

[5] E. Koutroulis and K. Kalaitzakis, "Design of a Maximum Power Tracking System for Wind Energy Conversion Applications," IEEE Transaction on Industrial Electronics, vol. 53, no. 2, April 2006, pp. 486-494.

An Autonomous Wind Energy Conversion System with Permanent Magnet Synchronous Generator

ABSTRACT:

This paper deals with a permanent magnet synchronous generator (PMSG) based variable speed autonomous wind energy conversion system (AWECS). Back back connected voltage source converter (VSC) and a voltage source inverter (VSI) with a battery energy storage system (BESS) at the intermediate dc link are used to realize the voltage and frequency controller (VFC). The BESS is used for load leveling and to ensure the reliability of the supply to consumers connected at load bus under change in wind speed. The generator-side converter operated in vector control mode for achieving maximum power point tracking (MPPT) and to achieve unity power factor operation at PMSG terminals. The load-side converter is operated to regulate amplitude of the load voltage and frequency under change in load conditions. The three-phase four wire consumer loads are fed with a non-isolated star-delta transformer connected at the load bus to provide stable neutral terminal. The proposed AWECS is modeled, design and simulated using MATLAB R2007b simulink with its sim power system toolbox and discrete step solver.

KEYWORDS:

1.      Battery

2.      Permanent Magnet Synchronous Generator

3.      Star-delta Transformer

4.      Voltage Source Converters

5.      Maximum Power Point Tracking

6.      Wind Energy

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Proposed control scheme of VFC for PMSG based AWECS

 EXPECTED SIMULATION RESULTS:

Fig. 2 Performance of Controller during fall in wind speed

Fig. 3 Performance of Controller during rise in wind speed

Fig. 4 Performance of Controller at fixed wind speed and balanced/unbalanced non-linear loads

 CONCLUSION:

A new configuration of voltage and frequency controller for a permanent magnet synchronous generator based variable speed autonomous wind energy conversion system has been designed modeled and its performance is simulated. The VFC has used two back-back connected VSC’s and BESS at intermediate dc link. The GSC has been controlled in vector controlled to achieve MPPT, unity power factor operation of PMSG. The LSI has been controlled to maintain amplitude of load voltage and its frequency. The VFC has performed the function of a load leveler, a load balancer, and a harmonic eliminator.

REFERENCES:

[1] J. F. Gieras and M. Wing, Permanent Magnet Motor Technology – Design and Application, Marcel Dekker Inc., New York, 2002.

[2] M. Kimura, H. Koharagi, K. Imaie, S. Dodo, H. Arita and K. Tsubouchi, “A permanent magnet synchronous generator with variable speed input for co-generation system,” IEEE Power Engineering Society Winter Meeting, 2001, vol. 3, 28 Jan.-1 Feb. 2001, pp. 1419 – 1424.

[3] T.F. Chan, L.L. Lai, Yan Lie-Tong, "Performance of a three-phase AC generator with inset NdFeB permanent-magnet rotor," IEEE Trans. Energy Conversion, vol.19, no.1, pp. 88- 94, March 2004.

[4] T.F. Chan, W. Wang, L.L. Lai, "Analysis and performance of a permanent-magnet synchronous generator supplying an isolated load," IET, Electric Power Applications, vol. 4, no. 3, pp.169-176, March 2010.

[5] K. Amei, Y. Takayasu, T. Ohji and M. Sakui, “A maximum power control of wind generator system using a permanent magnet synchronous generator and a boost chopper circuit,” Proc. of the Power Conversion Conference, PCC Osaka 2002, vol. 3, 2-5 April 2002, pp. 1447 – 1452.

A Unified Nonlinear Controller Design for On-grid/Off-grid Wind Energy Battery-Storage System

 ABSTRACT:

The goal of this paper is to investigate the application of nonlinear control technique to a multi-input multi output (MIMO) nonlinear model of a wind energy battery storage system using a permanent magnet synchronous generator (PMSG). The challenge is that the system should operate in both grid-connected and standalone modes while ensuring a seamless transition between the two modes and an efficient power distribution between the load, the battery and the grid. Our approach is different from the conventional methods found in literature, which use a different controller for each of the modes. Instead, in this work, a single unified nonlinear controller is proposed. The proposed control system is evaluated in simulation. The results showed that the proposed control scheme gives high dynamic responses in response to grid power outage and load variation as well as zero steady-state error.

KEYWORDS:

1.      Battery storage

2.      Bi-directional buck-boost converter

3.      Feedback linearization

4.      Grid-connected

5.      Multi-input mutioutput

6.      Permanent magnet synchronous generator

7.      Stand-alone

8.      Wind turbine

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. WECS based permanent magnet synchronous generator.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Optimum Rotor Speed and Output Power.

Fig. 3. Voltage and current of the load.

Fig. 4. dc-link voltage.

Fig. 5. Wind Turbine Output Power (MW).

Fig. 6. Load Power (MW).

Fig. 7. Charge/discharge of Battery (%).

Fig. 8. Grid Power (MW).

CONCLUSION:

This paper has proposed a nonlinear MIMO controller based on the feedback linearization theory to regulate the load voltage in both grid-connected and stand-alone mode while ensuring a seamless transition between the two modes and an efficient power distribution between the load, the battery and the grid. Our approach is different from the conventional methods found in literature, which use a different controller, PID based, for each mode of operation. Instead, in this work, a single unified nonlinear controller is proposed. The performance of the proposed controller has been tested with different wind speeds as well as in the two modes of operation with dynamic load. The simulation results show that applying nonlinear feedback linearization based control strategy provides a good control performance. This performance is characterized by fast and smooth transient response as well as good steady state stability and reference tracking quality, even with variable wind speed and dynamic load operation. However, this study assume that the system parameters are fixed. A future work will be to test the system when parameters are unknown using adaptive control design theory.

REFERENCES:

[1] M. Fatu, F. Blaabjerg, and I. Boldea, “Grid to standalone transition motion-sensorless dual-inverter control of pmsg with asymmetrical grid voltage sags and harmonics filtering,” IEEE Transactions on Power Electronics, vol. 29, no. 7, pp. 3463–3472, Jul. 2014.

[2] M. Fatu, L. Tutelea, R. Teodorescu, F. Blaabjerg, and I. Boldea, “Motion sensorless bidirectional pwm converter control with seamless switching from power grid to stand alone and back,” in Power Electronics Specialists Conference, 2007. PESC 2007. IEEE. IEEE, 2007, pp. 1239–1244.

[3] R. Teodorescu and F. Blaabjerg, “Flexible control of small wind turbines with grid failure detection operating in stand-alone and grid-connected mode,” IEEE Transactions on Power Electronics, vol. 19, no. 5, pp. 1323–1332, Sept. 2004.

[4] T. Chaiyatham and I. Ngamroo, “Optimal fuzzy gain scheduling of pid controller of superconducting magnetic energy storage for power system stabilization,” International Journal of Innovative Computing, Information and Control, vol. 9, no. 2, pp. 651–666, 2013.

[5] N. Instruments, “Improving pid controller performance,” 2009.