基于线电压调制的永磁同步电机弱磁控制

What is it about?

A line-modulation-based flux-weakening control is proposed for surface-mounted permanent-magnet synchronous machines. To evaluate the average dc bus voltage utilisation, the maximum line-modulation-ratio, which cannot be >1, is defined. If the maximum line-modulation-ratio is equal to 1, the voltage capacity of voltage-source-inverter is fully utilised, which means the dc bus voltage utilisation has been maximised. Without special declarations, the overmodulation scheme is not utilised in this study. The line modulation is employed in the proposed flux-weakening control, in which the average dc bus voltage utilisation can be maximised by regulating the maximum line-modulation-ratio to 1. Compared with the conventional fluxweakening control, the proposed one is simpler and its copper loss can be reduced. The reason is that the proposed fluxweakening control employs the line modulation while the conventional flux-weakening control usually adopts the space vector pulse width modulation. The effectiveness of the proposed flux-weakening control is verified by experimental results.

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Why is it important?

The main contribution of this paper is to make full use of the hexagon voltage trajectory instead of its inscribed circle voltage trajectory, in which the overmodulation scheme is not employed but the line modulation is used . As a result, the copper loss is reduced while the dc bus voltage utilisation is maximised. Besides, the low-pass filter is also eliminated.

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