Contribution à la modélisation et à la conception optimale des turboalternateurs de faible puissance
D. Petrichenko, L2EP, Laboratory of Electrotechnics and Power Electronics Ecole Centrale de Lille
Presentation plan Introduction and problem definition Developed approach Software implementation Applications Conclusion and perspectives
Introduction The objectives and problem definition
INTRODUCTION – Objectives Objective: Creation of a rapid tool used in optimal electromagnetic design of turbogenerators of power of 10-100 MW. Collaboration: Jeumont-Framatome ANP Moscow Power Engineering Institute (M.P.E.I.) CNRT (Centre National de la Recherche et Technologie), FUTURELEC-2
Introduction – Jeumont production Jeumont production: 2-4-6-n pole turbogenerators Power up to 1000 MW
Introduction – Turbogenerator particularities Big number of input parameters (up to 250): - complex geometry;
- stator and rotor slots of different configuration;
- cooling system with ventilation ducts;
- complex windings.
Big number of physical phenomena: - saturation phenomena;
- mutual movement of stator and rotor cores;
- axial heterogeneity of the cores;
- magnetic and electric coupling.
Introduction – existing methods Assumptions to classical theory: - energy transformation – in air-gap;
- salient surfaces of magnetic cores are replaced by non-salient;
- only first harmonic of the magnetic field is considered;
- field factors of flux density in the linear machine can be applied to saturated machine;
- main field and leakage fields of a saturated machine are independent;
- etc…
Introduction – existing methods
Developed approach Tooth contour method Permeance network construction Mode calculation
Developed approach Principles Axial heterogeneity Network construction: - Air-gap
- Tooth zones
- Yoke zones
Electromagnetic coupling Network equations Operating modes calculation
Developed approach
Developed approach – turbogenerator particularities
Developed approach – turbogenerator particularities Seven zones of influence of axial heterogeinity: - Stator yoke
- Stator teeth
- Stator slots
- Air-gap
- Rotor slots
- Rotor teeth
- Rotor yoke
Axial structure of the turbogenerator must be comprised in the permeance network in-plane in order to calculate properly the winding flux linkages. The material properties must be changed to reflect the influence of the axial heterogeneity.
Developed approach – air-gap zone Special Boundary Conditions: The current is distributed regularly in the wires. All other currents in the magnetic system are zero. The permeability of the steel is infinite.
Developed approach – air-gap zone
Developed approach – air-gap zone
Developed approach – air-gap zone
Developed approach – magnetic system
Developed approach – magnetic system
Developed approach – magnetic system
Developed approach – magnetic system
Approach – electromagnetic coupling Magnetic shells approach: - The shell is stretched on the sort of winding
Developed approach – electromagnetic coupling MMF sources The values depend on the ampere-turns which cross the layer with the : Form the matrix W which links together the branches of electric circuit and permeance network!
Developed approach – system of equations
Developed approach – Steady-state fixed rotor algorithm
Implementation Software implementation: TurboTCM
Implementation – the core. Circuit specification.
Implementation – component responsibilities
Implementation – software structure
Implementation – Matlab solver
Implementation – Graphical User Interface Allows: Set up a project: - Rated data;
- Geometrical descriptions;
- Winding descriptions;
- Axial configuration;
- Simulation parameters;
Perform the Model generation: - Generate magnetic permeance network;
- Generate electric circuits;
- Generate coupling matrices;
Perform some calculations: - Machines’ characteristics;
- Operating mode calculation;
Save the project and prebuilt model for further use from the command line or scripts (optimization).
Implementation – Various characteristic calculation
Implementation – Each operating mode output
Applications Small machine Two pole turbogenerator Four pole turbogenerator Optimization application: screening study
Application – Two pole machine of 3000 VA S = 3000 VA V = 220 V PF = 0,8 p = 1 24 stator slots Shaft with a separate BH-curve
Application – Two pole machine of 3000 VA 100 positions Excitation current of 20 A (saturated mode) Time of calculation in OPERA RM: 3h25min Time of calculation in TurboTCM: 18.3 seconds Gain in calculation time: 672.13 times
Application – Two pole machine of 3000 VA
Application – Two pole turbogenerator Several machines were tested: - Power of 31-67 MVA
- Voltage of 11-13.8 kV
- Frequency of 50-60 Hz
- Power factors of 0.8-0.9
No-load and short circuit cases were compared with experimental results In most cases errors do not exceed 3.5 %
Application – Two pole turbogenerator – no-load case
Application – Two pole turbogenerator – load cases
Application – Two pole turbogenerator – load cases
Application – Four pole turbogenerator
Application – Four pole turbogenerator Material properties were unknown - Linear modelisation fit completely
- In nonlinear case – the error was significant
Application – Different machines – conclusion The tool was validated on several types of machines: - Small 2 pole synchronous machine
- Two-pole turbogenerator
- Four-pole turbogenerator
No-load, short circuit and load characteristics are easily obtained. It’s possible to obtain special values from the results: - Electromagnetic torque
- Parameters Xd and Xq
- Air-gap flux densities
- Etc…
Application – Response surface study Objective: Demonstrate the use of TurboTCM together with an optimization supervisor. Variables: - hs1 – stator tooth height (±10%)
- bs1 – stator tooth width (±10%)
- Di1 – stator boring diameter (±5%)
- Tp1 – rotor pole width (±10%)
Responses: - KhB3 – 3rd order harmonic of air-gap flux density
- KhE3 – 3rd order harmonic of stator EMF
- KhE1 – the fundamental of the no-load stator EMF
- If – excitation current in no-load
Application – Response surface study results
Application – Response surface study. Conclusion. TurboTCM can be easily coupled with Experimental Design Method Different influence factors can be quantified The full factorial design was performed: - 81 experiments were lead
- It takes 25 minutes on a PC Pentium IV 2GHz.
Optimization can be performed using our tool
Conclusion and perspectives General conclusion and perspectives
Conclusion The main idea: exploit the particularities of a machine to minimize the number of the network elements. Axial heterogeneity: - taken into account on the stage of the network construction;
- the model is not a 2D model any more!
Flexible and adaptive PN construction, treating: - complicated geometries;
- irregular slot structure and distribution.
Fixed rotor algorithm – rapid steady-state calculations. Software TurboTCM is modular, scalable and flexible: - taking into account different machine configurations;
- different modes of use;
- easy coupling with optimization software.
The results are validated for several different types of machines.
Perspectives Expand the approach and software to other types of electrical machines. Implementation of additional methods of air-gap permeances calculation. Further development and extension by multiphysical phenomena: - Thermal circuit coupling;
- Vibroacoustic analysis.
Taking into account the Eddy-currents and hysteresis effects.
Thank you for attention!
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