Permanent magnet temperature analysis considering PWM carrier harmonics for interior permanent magnet synchronous generator in hybrid vehicles

In this paper, we investigate into an approach to predict the magnet temperature in interior permanent magnet synchronous generator for mass-produced front engine rear drive hybrid vehicles. To achieve an accurate thermal analysis, the generator losses under PWM converter drive are firstly calculated by 3D-FEM using measured current waveform including PWM carrier harmonics. As an approach for thermal analysis, a lumped capacitance model is proposed, which makes it possible to estimate the magnet temperature with fast computation. The thermal analysis is executed using the calculated losses and the experimentally obtained thermal resistance as the inputs. The calculated magnet temperature characteristics are in good agreement with the measured ones. As a result, it is verified that the proposed thermal analysis is effective for estimating the magnet temperature in this kind of application. © 2007 The Institute of Electrical Engineers of Japan.