B13_PC-BDC_XFACTORS SPEED教程

3.
Program Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Contents
1. 2.
X-factors in PC-BDC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Adjustment factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 2.2 2.3 2.4 Magnetic calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Inductance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Circuit calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SPEED TUTORIAL B13
1 July 2011
Adjustment Factors in PC-BDC
Objective
To explain the use of adjustment factors (also known as "X-factors", "calibration factors", etc) in PCBDC, and to provide suggested values or means of selecting values.
Output More geometry Weights & inertias Areas & volumes More winding data Slot-fill factors Winding harmonics Resistances Inductances Terminal performance Power Torque Efficiency Currents Current densities Losses Temperature rise Flux densities Special calculations Torque/speed Ranging Starting Phasor diagram
Note : The most commonly used X-factors are highlighted with the flag shown at left.
Note : When running the i-psi GoFER with interior-magnet motors, it is often the case that only XBrT, XCq and XCd are required, and these are the ones adjusted by the embedded finite-element solver. (See also DiffSat in the PC-BDC manual).
Fudge factor
Knowledge required
Basic theory of brushless permanent-magnet machines; basic operation of PC-BDC. Further reading : SEM —SPEED's Electric Motors, chapter 2; the WinSPEED manual; An Introduction to WinSPEED. For the basic operation of the PC-BDC program, see tutorial B01.
Material databases Steel Wire Magnets
FixfChop Bifilar
Special Finite-elements Scripting
Fig. 3
Organization of PC-BDC and its controls and adjustment factors
Wiபைடு நூலகம்dings Layout Turns Wire size
Drive/control Configuration Control settings
Connex Drive Sw_Ctl dq0 ChopType
XL XCd, XCq ETCalc, XLendt ufz
XLdiff CalcLdLq
Background
PC-BDC is based on classical analytical methods of calculation, which involve many simplifying assumptions and ideal models in order to achieve rapid calculation and good physical interpretation. To make allowances for things that cannot be calculated accurately, PC-BDC has various adjustment factors. These factors vary in importance and in the frequency with which they need to be used.
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1.
X-factors in PC-BDC
Input Options Geometry Configuration Dimensions RotType Embed Config S-Slot Polarity RCore WdgType WireSpec
Calculating engine Adjustment factors Magnetic calculations XBrT XFringe, XBetaM u_LKG, bBsat, Xrl XBtpk, XTTarc XTw, Xks XSYoke, XRYoke X_EMF XLM, Xrm Xkm_HB Fringing aPend XBGap uKCL Program controls CalcVer EMFCalc BgProfil CalcSatn XSatn SatnTol SlotMod XSlotMod Inductance PSSlot, muPlug, SpreadSO CalcCogg TempCalc ISLA Tol Tol_ISLA BreakIT Circuit calculations Lext Rext X_R Losses WFeCalc XFe LossFe Saliency dqRevert CalcVwfm WFeScale
The general organization of PC-BDC is shown in Fig. 1 together with the main program controls and adjustment factors. The main types of input data are shown in the left-hand box, and the main types of output data in the right-hand box. The "calculating engine" in the middle is the means by which the input data is mapped into the output data. Learning to "drive" the calculating engine is not merely a question of understanding the options and adjustment factors, but also of understanding the theory and the algorithms. Most of the "options" involve definite decisions. Thus RotType identifies a certain rotor type whose dimensions can be modified in the outline editor. Drive identifies the means of supplying electrical power to the machine, for example, by a squarewave or sinewave inverter. Connex identifies the winding connection: wye, delta, etc. "Adjustment factors", on the other hand, are somewhat less definite. A perfect calculating program would need no adjustment factors, but PC-BDC is far from perfect. The main adjustment factors can be classified as follows: (1) Saturation factors. By itself, PC-BDC calculates machines on a fundamentally linear basis except for the magnetic circuit on open-circuit. This is essential to permit the rapid calculation of the machine performance in circuit terms. Resistances, EMFs and reactances are generally quite accurate in the unsaturated condition, but in heavily saturated conditions PC-BDC relies on its partner PC-FEA to obtain saturation factors. A notable example is XCq when used with IPM motors. Allowances for real-world effects which are not included in the Ideal mathematical models. The mathematical models are simplified to make calculation feasible, but this means that several "real world" effects are omitted. Many of these effects are parasitic and second-order, but if the machine is driven to extremes of temperature, current density, or flux-density, their importance can increase dramatically. To some extent this type of imperfection can be corrected by comparing or calibrating PC-BDC against finite-element calculations, and the GoFERs described in the main manual are designed to do this efficiently. For example, adjustment factors such as XBrT, XBetaM, XFringe, bBsat are used to adjust the open-circuit flux-distribution, while XL, XCd, XCq are used to adjust the inductance or synchronous reactances. Measured data can and should be used for the same purpose.