L2 IntroSurvey. EIEN20 Design of Electrical Machines, IEA, Today s goal. L2: Variety of electrical machines.

Transcription

1 L: Variety of electrical achines Machine construction: an overview Transforer is it achine too? Today s goal ntroduction to achine construction Constructional layouts and echanical arrangeents Supply & control and Application & integration A few exaples ntroduction to achine analysis Methods and tools Analysis: paraeterisation, agnetic, theral pleentation: exaple and hoe assignent Lund University, Sweden Avo R Design of Electrical Machines Previous lecture A+ A+ A- M A+ A- M F F A+ M F A+ F M A- A+ A- F A+ A- M Magnetic field around current carrying coil Magnetic coupling The principle of operation of any rotating electric otor is derived fro Lorenz force Origin of forces Avo R Design of Electrical Machines 3 Avo R Design of Electrical Machines 4 EEN0 Design of Electrical Machines, EA, 016 1

2 Rotary achine rotating agnetic field Classification of electrical achines Magnetic coupling? Origin of forces? Avo R Design of Electrical Machines 5 Machine device that uses energy to perfor useful work = energy conversion, also transforation EM Gap-coil orientation (s) Type of excitation Power character Axial flux Circuferential flux Radial flux Transversal flux nduced, Reluctance Peranent/Electroagnet Hybrid AC, DC, odulated Rotary, Linear Avo R Design of Electrical Machines 6 Supply & Control Origin of forces DC achine asynchronous achine synchronous achine RM achine Constant or slowly varying supply DC AC Switched power u u t Constant or slowly varying supply in frequency or/and aplitude t Avo R Design of Electrical Machines 7 Avo R Design of Electrical Machines 8 EEN0 Design of Electrical Machines, EA, 016

3 Machine (excitation) types Separate excitation PM excitation agnet reluctance doinates, PMSM, BLDCM, DCM PM hybrids + reluctance odulation Field winding sall gaps and good pereability is useful, single or doubly fed Excitation via arature Miniize agnetization current sall air-gap and good pereability essential nduction, reluctance and stepping achines Cobined excitation Hybrid excitation Avo R Design of Electrical Machines 9 Constructional layout Cirular, Rotary Tubular Angular, Spherical Planar, Disk Cannular, Sandwiched Avo R Design of Electrical Machines 10 Air-gap versus flux path Application orientation Machine construction with respect to of the air-gap surface and the direction of the arature field. Radial 1- N/kg Axial 1-3 N/kg Circuferential 1-3 N/kg Transversal -10 N/kg Mechanical arrangeent nner/outer rotor Short/long over Type of echanical otion Rotary Linear Reciprocative or oscillatory Cobined Avo R Design of Electrical Machines 11 Avo R Design of Electrical Machines 1 EEN0 Design of Electrical Machines, EA, 016 3

4 Few exaples Rotary-to-Linear Linear drive: actuator vs achine Transfersal flux achine: claw-pole Electrically agnetised synchronous achine without sliprings Electroechanical energy conversion is efficient at a higher rotation speed than 0 Usually a linear oveent is needed in industries Avo R Design of Electrical Machines 13 Avo R Design of Electrical Machines 14 Linear actuator Electrical linear actuator Force, N Electrical Linear Actuators Pneuatic Cylinders Hydraulic Cylinders Screw Drives Rack-and-Pinion Pneuatic Rodless Cylinders Belt Drives Electrical Linear Motors Force, N Magnetostrictive & theral actuators Linear synchronous PM Motors Hybrid steppers Voice coil Actuators Reluctance Motors Solenoids Electrostatic Actuators Linear nduction Motors Distance, Avo R Design of Electrical Machines Distance, Avo R Design of Electrical Machines 16 EEN0 Design of Electrical Machines, EA, 016 4

5 Linear hybrid achine Claw-pole otor Digital-to-echanical stepper achine Tubular configuration Ø30/114 L /60 The priary part has winding and a PM Relatively high force and precision Avo R Design of Electrical Machines 17 Avo R Design of Electrical Machines 18 Electrically agnetised synchronous achine without sliprings Electroagnetic device calculations Windings Distributed Concentrated Peranent agnets Discrete Multi-pole Magnetic core Stack of lainations (D) ron powder (3D) Principle of operation Base on excitation Methods Siple approach Equivalent circuit ethod (Magnetic EC, Theral EC 1D eleents describing 3D object) Finite eleent ethod (ultiphysics D, 3D) Tools Matlab (Analytic odel, ECM, Design environent) FEMM (Magnetis + Heat transfer + ) Avo R Design of Electrical Machines 19 Avo R Design of Electrical Machines 0 EEN0 Design of Electrical Machines, EA, 016 5

6 Electroagnetic device calculations Geoetry siplification Procedure Geoetry and diensions Materials and their properties Physical processes and sources Boundaries and syetry Matheatical description of the physical process related to the geoetry and ediu Can flow be seen only on a plane? Siplify 3D proble to D Syetric repetition or reflection? Solve a section fro the whole Avo R Design of Electrical Machines 1 Avo R Design of Electrical Machines Geoetry paraeterization Electroagnetic circuit ins lc length height lc t is advisable to describe a device geoetry by a nuber of paraeters: proportions, (Variable) diensions or nubers g Electroagnetic, theral, etc forulation and calculations base on a paraetric geoetry input -core air-gap iron bar +N phi Fn -N Start fro static and continue with dynaics Apere s circuital law applied to agnetic circuit ΣHL = N Maxwell stress concept forces in agnetic field F=1/(μ 0 )B A Avo R Design of Electrical Machines 3 Avo R Design of Electrical Machines 4 EEN0 Design of Electrical Machines, EA, 016 6

7 Theral circuit Exaple q n=h(- ab) J ρk J f ρk f t D Q 0 Heat flows fro hotter to cooler regions Heat sources and sinks Fourier s heat conduction in the aterials Newton s convection boundary condition height Length Electric conductors with fill factor of Kf =0.6 [-] in a crosssection of 0.0x0.05 [] Current density J=e+6 [A/ ] Resistivity ρ.4e-8 [Ω] Specific loss q=j ρkf [W/ 3 ] Width Abient teperature =0 [C] Theral conductivity λ =0. [W/K] Heat transfer coefficient α=0 [W/ K] Avo R Design of Electrical Machines 5 Avo R Design of Electrical Machines 6 Analytic odel Equivalent circuit ethod Syetric part of geoetry 1D heat equation d d x q 0 q 0 r dx dr Solution q d / x d / q d / q q 4 r d / x r x r 1 ab G th1 coil G th ab 3 Guess heat flow paths for the syetric part of the geoetry Estiate heat conductivity eleents Forulate relations between teperatures at the node points and heat flow into the node point Solve the equation syste Avo R Design of Electrical Machines 7 Avo R Design of Electrical Machines 8 EEN0 Design of Electrical Machines, EA, 016 7

8 Finite Eleent Analysis Pre-processing Geoetry Material properties and heat sources Boundary conditions Discretization FE-esh Processing Post-processing Field distribution, flow density, etc Avo R Design of Electrical Machines 9 coil Pre-Processor Drawing the endpoints of the lines and arc segents for a region, Connecting the endpoints with either line segents or arc segents to coplete the region, Defining aterial properties and esh sizing for each region, Specifying boundary conditions on the outer edges of the geoetry. Avo R Design of Electrical Machines 30 Post-Processor Analytic vs. nueric odel 1.07e+00 : >1.49e e+00 : 1.07e e+00 : 1.165e e+00 : 1.13e e+00 : 1.080e e+001 : 1.038e e+001 : 9.958e e+001 : 9.535e e+001 : 9.113e e+001 : 8.690e e+001 : 8.68e e+001 : 7.845e e+001 : 7.43e e+001 : 7.000e e+001 : 6.578e e+001 : 6.155e e+001 : 5.733e e+001 : 5.310e e+001 : 4.887e+001 <4.04e+001 : 4.465e+001 Density Plot: Teperature (K) Estiate hot-spot and average coil teperature for a given loss density and cooling conditions Teperature distribution indicates the theral loading Differential equations that describe physics can be solved for a siple geoetries Equivalent circuit ethod has a low nuber of eleents, which akes it relatively fast and inaccurate Finite eleent ethod has a high nuber of eleents, which akes it relatively slow and accurate The sources in EC are concentrated and FE odel distributed Avo R Design of Electrical Machines 31 Avo R Design of Electrical Machines 3 EEN0 Design of Electrical Machines, EA, 016 8

9 1 transforer Hoe assignent Analysis of heat transfer in a singlephase transforer Lund University, Sweden Priary winding is agnetically loaded by secondary winding deally no power losses, no voltage or agnetootive force drop across the corresponding circuits Avo R Design of Electrical Machines 34 Assignent goals Perforance equations Estiate transferred power capability by studying the liits for cooling power at axiu teperature Learn to use finite eleent (FE) and equivalent circuit (EC) odel for heat transfer Select one of the TRAMO-ETV transforers to diension and validate your odel Apparent power S 1 U Voltage d t dt u t U cos t e t N dt dt Magnetic flux U t sin t sin t B A sin t N Current N i t cos t cos t N J Ae cos t N Ability to transfer power 1 1 S U BJ Ae A Losses P A l q A l q loss e e e Core losses are estiated fro the specific loss curves Flux density is constant Avo R Design of Electrical Machines 35 Avo R Design of Electrical Machines 36 EEN0 Design of Electrical Machines, EA, 016 9

10 Paraeterization Progra structure A single phase shell type of transforer The influence of end turns are excluded The sae electric loading is assued in priary and secondary coil Paraeterization Lengt Geoetric proportions Magnetic loading Material properties Paraetric change Geoetric odelling Sensitivity study Derive geoetry in Proportion between respect with paraeters agnetic and electric circuits D Finite Eleent Method D Equivalent circuit ethod Heat transfer (Mirage)) Theral circuits Objective Estiate electric loading Transforer specification The goal of the calculation is to find optial relation between agnetic and theral circuit The FE odel of heat transfer is established in lua script The EC odel of heat transfer is established in script Avo R Design of Electrical Machines 37 Avo R Design of Electrical Machines 38 terative calculations Theral equivalent circuit nitialization Cooling conditions Magnetic: B -> pfe Electric: Jk,ρ0 -> pcu Find teperature Coil hot-spot ax Coil average ave Target target - ax 0.05 iter ax_iter Result visualization Teperature plot (bp) Electric loading (txt) Obtain new values ρ= ρ0(1+α(ave-0)) pcu=0.5 ρ (Jk+1) Kf iter=iter+1 Obtain current density if target - ax < - 40 then Jk+1=Jk x 0.5 if target - ax > 40 then Jk+1=Jk x else Jk+1=Jk W(target - ax) The goal of the coputation routine is to estiate current loading within the theral liit Theral dependence of copper is taken into account Theral conductivity network of 11 eleents Syetric part of core Copper losses are applied to node and 3, core losses to node 1 Convection eleents are 4 and 11 Avo R Design of Electrical Machines 39 Avo R Design of Electrical Machines 40 EEN0 Design of Electrical Machines, EA,

11 Assignent Copare the estiated current density fro Fe and Matlab (e.g. Excel table) nterpret/validate the ethods and results What geoetric proportions between the electric circuit and agnetic gives the highest transferred power and which the highest efficiency What is the difference between ECM and FEM estiations and what ight be the reason How realistic you think the odels and estiated results are Avo R Design of Electrical Machines 41 EEN0 Design of Electrical Machines, EA,