Accurate Analytical Method for Magnetic Field Calculation of Interior PM Motors

Simplified Analytical Model for Rapid Evaluation of Interior PM Traction Machines Considering Magnetic Nonlinearity

“…Based on the obtained dq-axis airgap flux densities in (17) and (20), the dq-axis inductance of IPM machine is determined as shown in (21) where kad(dq) is the dq-axis adjustment factors associated with the difference in the fundamental value between the actual dq-axis armaturereaction airgap flux densities (17), (20) and the ideal case (12) [4], [26], [27]; Llk is the phase leakage inductance.…”

“…Analytical researches for IPM machine were presented in [3]- [17]. Air-gap field analysis of a line-start IPM machine for determination of dq-axis inductances and back-EMF was introduced in [3].…”

“…However, only analysis result as a function of phase current (q-axis) was presented in [15] and analysis result of one specific operation point was shown in [16]. In [17], a high fidelity EMC model considering individual stator slot reluctances, segmented airgap reluctances, and segmented rotor reluctances was suggested. However, two separate nested-process-loops with multi-loop-variables must be solved for determining one operation point.…”

“…However, two separate nested-process-loops with multi-loop-variables must be solved for determining one operation point. As a result, computation time of the proposed method in [17] is only reduced by 30% compared with the FEA. To the best knowledge of the author, analytically rapid solution for sufficiently predicting IPM machine parameters from a given design specification considering magnetic nonlinearity under full range on-load dq-axis currents is quite limited and this is the main subject of the paper.…”

“…It is noted that determination of optimum dq-axis currents over torque-speed performance map was well presented in [1], [2] and [23] and is not discussed in the paper to avoid duplication. In comparison with high fidelity EMC model techniques [6], [7], [13], [17] where multi-loop-variables must be iterated within a process loop, the proposed method with only a single loop-variable is simpler and therefore could be employed for rapid nonlinear magnetic analysis under full range on-load dq-axis currents with a reasonably accurate level. Under the proposed method, sufficiently accurate machine parameters (up to 10% difference under extremesaturation and deep-FW operations), and efficiency (up to 1% efficiency difference within main torque-speed operation region) of the tested IPM machine compared with FEA can be produced within minutes.…”