ANALYSIS OF ELECTRONIC LOAD CONTROLLER
FOR THREE PHASE SYNCHRONOUS GENERATOR
USING FUZZY LOGIC
Presented by: ANURAG YADAV
Guided by : Dr. S.N. Singh
Alternate Hydro Energy Centre
INTRODUCTION
Energy is the basic requirement for economic development
Mainly Coal, Petroleum, Natural gas, nuclear etc. are used to be
exploited as versatile and high quality energy products
Utilities in many developing countries are finding it difficult to
establish and maintain remote rural area electrification and other
needs
The cost of delivering power to such areas is becoming excessively
large due to large investments in transmission lines and large
transmission losses
For these reasons, many utilities are seriously considering local
ADVANTAGES OF HYDROPOWER
Clean energy source
Renewable source as it doesn’t utilize any fuel
Environment friendly
Easily integrable with grid and other energy
sources and can easily meet peaking demands
Very high conversion efficiency
OBJECTIVES
To develop the model of ELC in MATLAB/Simulink
To simulate the model and analyze it for various operating
conditions
SCHEME OF ELC
ALTERNATO
R
ELECTRONIC
LOAD
CONTROLLER
CONSUMER
LOADS
BALLAST/DUMP
LOAD
ADVANTAGES OF ELECTRONIC
LOAD CONTROLLER
Reduces the cost of Small Hydro installation
Provides smooth control of Voltage and Frequency
Efficient than a conventional hydraulic governor as it is faster
in response
No complications and maintenance is very less
Maintains constant load on the generator irrespective of
consumer load variations
SYNCHRONOUS GENERATOR
It works on the principle of electromagnetic induction
It runs at synchronous speed which is fixed by the line frequency and no. of
poles
It can both export or import reactive power depending upon the type of
excitation
Stable in operation and control
They are of Salient-Pole type or Cylindrical rotor type
LITERATURE REVIEW
AUTHOR(
s)
TOPIC
WORK AND RESULTS
Jan Portegijs[1]
2000 The Humming Bird ELC/Induction Generator
• The humming bird ELC for both single phase and three phase Induction generator is being developed.
• Thyristorized control has been used to control the dump power consumption with two ballast loads.
• Design considerations for building and troubleshooting an ELC were described.
• Design is quite simple but its major disadvantage is the electronic noise which is due to the phase angle control strategy employed.
Arun Kant [2]
2002 Design and development of a controller for Single Phase Induction Generator
• A design for load controller for Single-phase Induction Generator is developed.
• A circuit for sensing the reference and actual frequency has also been developed.
• Hardware of ELC has been developed using IC 555 timer utilizing the solid state electronic devices and circuits.
• Under-voltage,Overvoltage,Over-speeding protections are also being incorporated in the model.
• The model provides quite smooth control of voltage and frequency S.S. Murthy,et al. [3] 2003 Field experience on a novel pico hydel system using SEIG and ELC
• The field experience is being done by exploiting locally available small hydro potential needing minimal civil works
• Water is made to flow in a channel and stored in a forebay tank whose discharge is regulated to have nearly constant head.
• Thyristor based, diode based, Mark-space ratio/PWM based ELC’s were developed and these are being compared for their voltage regulation.
V. Aggarwal [4] 2004 Techno-economic study of micro hydro-turbine governing systems
• Study is being carried out keeping in mind the economic aspects of the turbine governing system.
• It is being concluded that the cost of penstock of ELC based system is less as the flow is constant.
• Constant flow condition also eliminates the water pressure or surge pressure.
• It also eliminates the use of regulating equipment like guide vanes which further adds to cost reduction.
S.P. Singh [5]
2004 Design and development of single phase ELC for micro hydro power plant
• Worked and designed an ELC for a single phase system.
• Design consistes of an uncontrolled rectifier in series with chopper switch (IGBT) which is given pulse signal by PWM controller to control the switching.
• Voltage and frequency are thus controlled and regulated. S. Singh[6]
2006 Design, testing and sensitivity analysis of ELC • ELC is designed using phase angle regulation scheme which can vary from 0 to п. • The ELC is being made for single phase system and back to back
thyristors are being used in its design as it can be operated in both directions.
• Switching occurs at twice the frequency and thus generates harmonic distortion as high as 35-40%.
• The results show that design is succesful for single phase system and that too upto 7kW.
B. Singh[7]
2006 Analysis and design of ELC for SEIG
• ELC is being designed for stand-alone operating mode.
• Uncontrolled rectifier and chopper based ELC is being developed with resistive dump load.
• IGBT is being used as a chopper switch.
• It is being concluded from transient and steady state waveforms that ELC is able to maintain constant voltage and frequency. This type of ELC can handle large power as compared to single phase one.
S.S. Murthy, et al[8] 2006
A Novel Digital Control Technique of Electronic Load Controller for SEIG Based Micro Hydel Power Generation
• The work presents both transient and steady-state analysis of ELC • The operation of ELC is controlled using digital controller.
• The controller is being tested in both laboratory and field.
• This design of ELC is found to be more effective, faster, reliable, compact and cost-effective.
J.M Ramirez, et al[9]
2007
An Electronic Load Controller for Self-Excited Induction Generator
• The proposed ELC is reliable, simple and injects fewer harmonics. • The proposed ELC is conformed by a per-phase chopper circuit in
series with dump load
• Each switch is a combination of a couple of IGBT in anti-parallel connection.
• The commutation pulses are obtained by PWM technique. D.K. Palwalia,
et al[10] 2008
Voltage and Frequency regulation of single phase SEIG
• ELC is being developed for single phase two-winding squirrel cage induction motor
working as SEIG.
• The error is generated based on the voltage difference between the actual and the reference.
• The error signal is compared with internally generated triangular wave of PWM generation scheme which generates the pulses for firing the IGBT through an opto-isolation and pulse driver circuit.
B. Singh, et al [11] 2008 VSC with Star-Delta Transformer based Electronic Load
Controller for a stand alone power
generation
• The proposed scheme presents an asynchronous generator driven by a pico hydro turbine and controller is connected at a point of common coupling through interfacing transformers.
• A star-delta transformer is used to form a four wire topology. It provides path to zero-sequence component of load current.
• Transformer is of three winding type with turns ratio as 2:2:1.
• ELC serves the purpose of harmonic elimination, load balancing and reactive power compensation for voltage control.
• The results show that three phase system is balanced and sinusoidal. B. Singh, et al
[12] 2008
Power Quality improvement in Conventional ELC for isolated power
generation
• The designed ELC scheme consists of a 24-pulse rectifier with 14 diodes and a chopper.
• A polygon wound autotransformer is being employed with reduced kVA rating for 24 pulse rectifier for harmonic reduction and to meet the power quality requirements as prescribed by IEEE standard-519.
• ELC’s are being developed using two schemes viz. six pulse bridge type and 24 pulse bridge type.
• The performance of both designs are being compared and it is concluded that 24 pulse bridge type ELC yields better performance. • Experimental validation of the design has also been done.
B. Singh, et al[13]
2008
Zig-zag transformer based ELC for isolated Asynchronous
generator
• In this scheme, the VSC(Voltage source converter) and a zig-zag transformer are connected in shunt with the stator terminals of the generator.
• The neutral terminal for the consumer loads is created using a zig-zag transformer.
• Two legs of the VSC are connected to the two phases while third phase is connected at the mid-point of the DC bus capacitors of the VSC. • The cost, complexity, of ELC is less as compared to other ELC’s for
H. Ludens[14]
2010 Electronic Load Controller for Micro-hydro system
• The ELC is being developed for a single phase system. • The power circuit consists of eight TRIACs
• It also employs a power transformer consisting of two secondaries. • One of the secondary is utilized to feed the line frequency and the
other one to power the control circuitry of thyristor.
• ELC based on this scheme gives satisfactory performance. V. Rajagopal
[15] 2010
Electronic load
controller for isolated asynchronous
generator in pico hydropower generation
• The work proposes a digital signal processor based ELC for asynchronous generator.
• The control circuitry consists of excitation capacitors, voltage source converter, dc link capacitor, a chopper, star/delta transformer, consumer loads and an auxiliary load.
• The system provides a viable and cost effective solution to achieve power quality improvement, voltage and frequency control, harmonic suppression and load balancing for feeding non-linear loads.
Anurag Chauhan [16] 2010 Transient analysis of self-excited induction generator
• The ELC is being simulated for transient conditions such as process of self-excitation, voltage build-up, faults, unbalanced excitation, switching of resistive and dynamic loads.
• SEIG can safely feed an induction motor rated upto 50% of its rating. • Three-phase fault, L-L fault and unbalanced excitation cause voltage
collapse and de-excitation.
• The dynamic behaviour of SEIG with ELC is satisfactory in constant power applications.
Shalini Singh[17] 2010
Design and testing of ELC for hydropower plant
• The ELC in this scheme is designed and fabricated using thyristors. • The input is taken from generator through step down transformer and
using the control circuit, the triggering pulses are fed through the pulse transformer for gating the thyristors.
• The ELC is tested and shows that it is capable to maintain almost constant voltage. S.N. Mahato, et al[18] 2010 Transient performance of a three-phase SEIG supplying single phase load with ELC
• The work presents an SEIG feeding a single phase inductive load. • The effect of cross-saturation has also been incorporated.
• The developed model has been validated through experiment by sudden removal and application of load so as to check the effectiveness of the model.
S. Gao, et al[19] 2010
Design of a
Microcontroller based ELC for SEIG supplying Single Phase Loads
The ELC has been designed using Microprocessor interface. The ELC is an intelligent sensor in this case
The operation of the controller is fast and also smooth and reliable control is obtained.
B. Singh, et al [20]
2011
Electronic Load
Controller for a Parallel Operated Isolated Asynchronous Generator Feeding Various Loads
The ELC is developed for induction generator operating in stand-alone mode.
The model is simulated for linear/non-linear, balanced/unbalanced loading conditions.
The controller is PI based.
B. Singh, et al[21]
2011
Neural-Network-Based Integrated Electronic Load Controller for Isolated Asynchronous Generators in Small Hydro Generation
The work proposes a neural-network based integrated ELC for isolated asynchronous generator feeding a three-phase four wire load.
The scheme uses adaptive linear element to extract the fundamental component of load current to control the voltage and frequency.
The IELC is realized using zigzag/three single-phase transformers and a six-leg insulated-gate bipolar-transistor-based current controlled voltage-source converter, a chopper switch, and an auxiliary load on its dc bus. The model was simulated and also validated and found to give satisfactory performane.
The controller is also simple, easy to control and less sensitive to load perturbations.
V.
Rajagopal[22] 2011
Improved ELC for offgrid Induction Generator in SHP generation
ELC is being implemented using a digital signal processor.
The design also balances the system under unbalanced loading conditions and also eliminates the harmonics in the load.
THD of load current and terminal voltage lies within 5% as prescribed by IEEE-519 standard.
Performance is very good under non-linear and unbalanced loading conditions.
Anjali Garg, et al [23]
2011
A Fuzzy Logic Based Electronic Load Controller for Self-excited Induction Generators
The proposed scheme presents a fuzzy logic based ELC for asynchronous generator.
The load current is being compared with the reference current and based on the error signal the input goes into Fuzzy logic controller.
The proposed ELC gives better performance as compared to conventional controllers due to the use of fuzzy logic scheme.
Dibyendu Das[24] 2011
Steady-State analysis of Electronic Load Controller for Three Phase Alternator
• The ELC is being developed using PD, PI and PID controller techniques. • The performance of ELC based on the three techniques is being
compared and the effect of varying the proportional, derivative and integral gain constants is also discussed.
• It is being concluded that PID based controller gives better performance as compared to other two.
• The system is not state controllable but the output is controllable as desired. Érika S. Melo, et al [25] 2013 Electronic Load Controller of a Micro-Hydro generator for stand-alone operation
The proposed scheme presents an ELC for single phase permanent magnet synchronous generator operating in isolated mode.
A switched binary-weighted ballast load is connected in parallel with the main load.
Binary-weighted resistors consists of six resistors connected in series. Each switch is triggered in integer cycles and on/off combinations provide 64 options of equivalent resistances that vary linearly.
Comparison is being done between actual and reference frequency. The controller employed here is of PI type.
Better results can be obtained by connecting more resistors to the ballast load.
Peeyush Kala[26] 2013
Steady-state analysis of Fuzzy logic based ELC for SEIG
• In this scheme, fuzzy logic based ELC is being developed for self-excited induction generator.
• The model is simulated in MATLAB/Simulink environment.
• The error signal is fed to the fuzzy logic controller based on the comparison between reference voltage and actual voltage.
• The results show that a better and quick restoration of the system takes place with Fuzzy logic based controller.
Yellaiah. Ponnam [27] 2013
ELC for SEIG using fuzzy logic controller
• The proposed scheme consists of a Fuzzy logic based controller for SEIG operating in isolated mode.
• The error signal is generated by the comparison between the actual voltage and the reference voltage.
• Fuzzy logic based ELC gives faster response and the peak overshoot is also reduced.
C.Kathirvel, et al [28]
2013
Fuzzy logic based voltage and frequency of a self excited
induction generator for micro hydro turbines for rural applications
• The ELC based SEIG has been designed in this work.
• The design is being tested using simulation in MATLAB/Simulink.
• It is concluded that STATCOM or any other reactive power supply device needs to be integrated with fuzzy in order to keep the voltage perturbations within safe limits.
B. Nia Roodsari , et al [29] 2014 The Distributed Electronic Load Controller: A New Concept for Voltage Regulation in Micro hydro Systems with Transfer of Excess Power to Households
• The work presents a concept of distributed ELC.
• The power going as a waste or dump to ballast load is utilized in various household usage nearby.
• This scheme provides good regulation of voltage and frequency.
• The results showed that distributed ELC has more reliable performance than a conventional one.
M. Prabhu Raj, et al[30]
2014
Fuzzy Logic Control Strategy for Stand-Alone Self-Excited Induction Generator for a Variable Speed Wind Turbine
• The work presents a control strategy for SEIG connected to wind turbine and operating in isolated mode.
• The strategy aims to extract the maximum energy from the turbine and simultaneously regulating the terminal voltage over a wide range of speed variations.
• The dynamic performance is achieved using three fuzzy logic controllers.
B. Nia Roodsari , et al [31] 2014
A New Electronic Load Controller for the Self-excited Induction Generator to Decrease Stator Winding Stress
• In this technique, a part of the dump load is being connected vin parallel with the consumer load so that stress on the stator windings can be reduced.
• The duty cycle varies with the variations in main load, which requires constant connection and disconnection of the ballast load.
• In the proposed scheme the ballast load has been divided into two parts for the reasons explained above.
