Effect of parameters on back-EMF in permanent magnet brushless DC motor with concentrated winding
A method for analyzing the concentrated windings back-EMF in permanent magnet brushless DC motor, based on the analytical calculation of one phase back-EMF by using Fourier series, has been developed and validated by comparing computing waves to measured waveforms. And the paper discussed the influence on back-EMF of design parameters.
Analytical Modelling of Rotor Magnetic Characteristics in an Interior Permanent Magnet Rotor
This chapter proposes a technique for analytical modelling of the non-homogenous magnetic saturation in the IPM rotor iron, based on which an analytical model for calculation of the PM flux density is proposed. The principles of the magnetic equivalent circuit in electric machines are first explained. The flux paths in a V-shaped IPM rotor due to the magnet residual flux are then classified into five groups. Accordingly, geometrical relationships in the IPM rotor are derived and used in analytical modelling of the non-homogenous magnetic saturation in the rotor iron. The B-H curve of the rotor core material is taken into account in the proposed approach. The proposed model provides information regarding the flux density and relative permeability of the iron in different regions of the rotor. In the next step, the state of the art analytical model for the PM flux density in the airgap is briefed, for which, a novel model is then proposed that is based on the novel magnetic saturation map that was derived earlier in this chapter. A case-study was then investigated to evaluate the proposed techniques using FEA and experimental results from the prototype machine.
LABORATORY AND FIELD TESTING OF SEED SPACING UNIFORMITY FOR SUGARBEET PLANTERS
Five planter configurations were evaluated for seed spacing uniformity at three field speeds using a seed 
location method in the field and a laboratory method involving an opto-electronic sensor system. Planter seed spacing 
uniformity was described using the Coefficient of Precision (CP3) measure. Results showed that CP3 measures 
determined using the laboratory test method were significantly different from those determined using the field test method. 
This indicated the laboratory test method cannot be used to predict planter seed spacing uniformity in the field. Seed 
spacing uniformity determined in laboratory tests was higher than, or equal to, seed spacing uniformity determined in 
field tests. This indicated the laboratory test method may be useful to screen out planters or planter units with poor 
uniformity of seed metering. Field testing of the planters that perform well in laboratory tests must be conducted to 
adequately determine the seed spacing uniformity of those planters in the field. Results from laboratory and field tests 
could be useful in determining areas for improvement of planters or planter units.