Testing Small Wind Turbine Generators - Renewable and ...

More documents

Recommendations

Info

2.6.2 Electrical SystemTo load the three-phase AC generator with resistors, it is first necessary to rectify itsoutput. This is done with a three-phase bridge rectifier rated to 35 amps and 800 volts. Therectifier is shown in Figure 2.20, and its specifications are given in Appendix A, Figure A.7.The rectifier is mounted directly to one of the Unistrut support beams. To facilitate heattransfer from the rectifier without the use of additional cooling fins, this support beam ismade from aluminum rather than steel. In addition, heat-transfer grease is applied betweenthe metal rectifier face and the aluminum beam. The DC output of the bridge rectifieris fed directly into the resistors. Depending on the type of load required for a given test,these resistors may be connected in series, in parallel, or in some combination of series andparallel.To facilitate making inter-resistor connections quickly and securely, each terminal ofeach resistor is fitted with a bolt and wing nut. Short lengths of wire, fitted on each endwith a spade terminal, can be easily secured onto the resistor tab with the wing nut, asshown in Figure 2.21.Figure 2.20. Three-phase bridge rectifierconnected to the generator leads anddump load.Figure 2.21. Resistor connection assemblieson the dump load.2.6.3 Mounting StructureIt is necessary to keep the resistors elevated, so they do not overheat, and separate,so they do not accidentally short each other out. For these reasons, a mounting system is31
developed to hold the resistors in place. Like the dynamometer platform, it is constructedfrom Unistrut components. Each resistor is supported by a long bolt through its hollowaxis, which compresses the resistor between L-brackets on each end. This structure is shownin Figure 2.22, where one resistor is mounted and one resistor has been removed to exposeits supporting hardware. The entire dump load structure is shown in Figure 2.23. Alsovisible in this photograph is a shunt resistor, which is discussed in Section 2.7.To test the CE&P generator up to 1.0 kW, at least four of these 300 watt resistors areneeded at a time. The mounting structure, however, is sized to hold up to five resistors,allowing additional permutations of resistor connections.Figure 2.22. Mounted resistor and exposed resistor-mounting structure on the dump load.2.7 MeasurementTo adequately characterize the generator’s performance during testing, five key measurementsmust be taken:1. Motor/generator rotational speed2. Motor input voltage3. Motor input current32
Page 1 and 2: Testing Small Wind Turbine Generato
Page 3 and 4: Testing Small Wind Turbine Generato
Page 5: “And now,” cried Max, “let th
Page 8 and 9: 2.5 Control System . . . . . . . .
Page 11 and 12: List of Figures1.1 California Energ
Page 13 and 14: List of Tables2.1 Phase names and a
Page 16 and 17: Chapter 1IntroductionHorizontal boo
Page 18 and 19: Figure 1.1. California Energy and P
Page 20 and 21: Chapter 2System DesignI had investe
Page 22 and 23: instantaneous shaft position, a dig
Page 24 and 25: consist of only one deep channel, s
Page 26 and 27: Figure 2.4. One of two roller platf
Page 28 and 29: 1/2”. The next has an inside diam
Page 30 and 31: Motor ConnectionsPhase Name DC Posi
Page 32 and 33: Figure 2.10. Active motor phases fo
Page 34 and 35: meet these requirements are ON Semi
Page 36 and 37: and to ground. This current flow al
Page 38 and 39: Figure 2.17. Assembled control circ
Page 40 and 41: indefinitely to continuously keep t
Page 42 and 43: difference is divided by the one se
Page 44 and 45: is independent from the main DC pow
Page 48 and 49: Figure 2.23. Complete dump load, in
Page 50 and 51: Chapter 3TestingThe perception of e
Page 52 and 53: 1. Begin with no dump load resistor
Page 54 and 55: The dynamometer frame was slightly
Page 56: to address this problem.While a sol
Page 59 and 60: 4.1 OverviewOnce testing has been p
Page 61 and 62: is the same for all phases: R P = 0
Page 63 and 64: Curve Number Basis Equation1 T F =
Page 65 and 66: Figure 4.5. Difference between mode
Page 67 and 68: elated to the DC output voltage by
Page 69 and 70: T T = 1 (√ω 3VLM I M − I 2 )M
Page 71 and 72: The resultant model is then checked
Page 73 and 74: Table 4.3 shows the final generator
Page 75 and 76: Efficiency EquationLastly, the gene
Page 77 and 78: Figure 4.8. Generator line voltage:
Page 79 and 80: more bits of information: the rated
Page 82 and 83: Chapter 5Summary and ConclusionsThi
Page 84 and 85: Dynamometer1. The dynamometer is a
Page 86: BibliographyLieu, P. D. K., Design
Page 89 and 90: Figure A.1. Primary transistor spec
Page 91 and 92: Figure A.3. Quadrature optical enco
Page 93 and 94: Figure A.5. Digital signal processo
Page 95 and 96: Figure A.7. Three-phase bridge rect
Page 97 and 98:
Figure A.9. Operational amplifier s
Page 99 and 100:
Figure B.1. Dynamic C code, page 1
Page 101 and 102:
Page 103 and 104:
Page 106 and 107:
Appendix CRaw Test DataFigure C.1.
show all

Testing Small Wind Turbine Generators - Renewable and ...

Create successful ePaper yourself

Delete template?

Save as template?