Electric Machine Design using SPEED and Motor-CAD
FC-IV CONTROLLER
MACHINE INVERTER
Page 5
LOAD INVERTER
Gate drives Current
SPEED Reference
Resolver TORQUE
SPEED
Test Machine
Load Machine
Ldc iLdc Vs
iDC
Q1
ICdc 0
D1
Vt
VCdc
D3 Q3
D5 Q5
Cdc Q4
Q6
Q2
D4 Rdc
R_s
D6
D2
iRec iB
iA
iC
Lac Leads Rac v1
A i1
vAB B
C
i2
i3
Lph
Rph e1
e2
e3
Frame
Fig. 1.3 The SPEED system
1.7
The SPEED system — features, functions, and auxiliaries
In Fig. 1.3 the basic design process of Fig. 1.2 is illustrated with some of the features already mentioned, such as the OUTLINE EDITOR, the WINDING EDITOR, the DESIGN SHEET, and the GRAPHS. At the lower left of Fig. 1.3 is a condensed figure of a dynamometer and a circuit diagram for an inverter-fed AC machine, referring to the simulation of the drive and its digital control found in many SPEED programs. Fig. 1.3 also shows a number of important auxiliary functions and links. The finite-element GoFER — this is a closely linked finite-element program (PC-FEA) which is provided to assist with electromagnetic field calculations. “GOFER” stands for “Go to FiniteElements and Return”. The data transfer from SPEED to PC-FEA is automatic, although it can be controlled and modified by the user at all stages of the process.2 “Return” refers to data that can be passed back to SPEED for directly improving the design calculations in several different ways. 2
The FLUX™ finite-element software by CEDRAT can read SPEED datafiles of type .bd4, .im1 and .srd directly. Thereafter FLUX™ can be used flexibly for a wide range of finite-element calculations. Moreover, FLUX™ has excellent facilities for modifying the geometry with holes, flats, notches, and imperfections such as eccentricity.
The finite-element process is also used internally in some SPEED programs as an embedded solver. In this case the finite-element results are incorporated in the design calculations without displaying the flux-plot or other graphics available with the GOFER. Some calculations require this solver. The material property databases are important repositories for material property data in a form that is readable by the SPEED programs. Given the critical importance of material property data, it is essential that users prepare their own data records for materials used in their products. This data is often proprietary, particularly when it has been hard-won by painstaking efforts in the test laboratory, or by negotiation with suppliers. The material data supplied with the SPEED programs is generic and unqualified. It should only be used as a “starter”, or as representative of certain general classes of material, for example, “highsilicon steel”, or “neodymium-iron-boron”. There is an important link to Motor-CAD™ for heat-transfer analysis and cooling calculations. Finally there are facilities for linking SPEED data to manufacturing design databases such as those used with product inventories.