A Reverse-Salient Permanent Magnet Synchronous Motor and Its <i>dq</i>-Axis Current Distribution Laws
Xiaokun Zhao, Baoquan Kou, Changchuang Huang
Abstract
The reverse-salient permanent magnet synchronous motors (RSPMSMs) have attracted considerable attention in electric vehicles due to their wide constant-power speed range. However, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -axis current distribution laws of the RSPMSM are absent, and the relationships between motor parameters and the constant-power speed range are still unclear. First, the flux-intensifying effects and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -axis current distribution laws of the RSPMSM are investigated. Second, the relationships between motor parameters and the constant-power speed range are summarized. Then, an RSPMSM with a wide constant-power speed range is proposed. The electromagnetic performance of the proposed RSPMSM is investigated by finite element method simulations and is compared with a conventional interior permanent magnet synchronous motor. Finally, an RSPMSM prototype is manufactured and tested. The results show that the RSPMSM exhibits favorable characteristics such as a wide constant-power speed range, weak flux-weakening current, high permanent magnet operating point, strong short-circuit current suppression capability, and high efficiency at a high speed. The constant-power speed range tested by the experiment reaches 5.5:1. Thus, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -axis current distribution laws, the relationships between motor parameters and the constant-power speed range are of great significance to the design of the RSPMSM.