在利用改进绕组设计对电机进行双速或多速节能改造时，存在一些特殊工况要求不同转速时的能效尽可能接近，这就需要对定子绕组进行特殊设计以实现2种转速条件下效率最优。针对该需求，对比了3种单绕组双速电机实现方案，对比发现反向换相法在2种极对数情况下均能保持较高的基波绕组系数，进一步利用有限元方法研究了不同节距和绕组匝数对电机运行性能的影响，并提出了最优的绕组设计方案。以1台5.5 kW、4极电机为例，利用所提方法进行4/6极绕组设计并进行试验验证，结果表明2种转速下电机效率基本一致，验证了所提设计方法的可行性及有效性。

Currently, two-speed or multi-speed energy-saving remanufacturing of motor system is generally realized by improved design of stator winding. But the energy efficiency at different speeds should be close to each other so that the optimal efficiency can be achieved under different rotating speeds in some special conditions. In response to this demand, three single-winding two-speed schemes of stator winding are compared, and it is found that the reverse commutation method can maintain a relatively high fundamental winding factor for both pole pair numbers. The effects of different pitches and winding turns on the motor performance are analyzed by finite element method, and the optimal winding design scheme is proposed. Taking a 5.5 kW, 4-pole motor as an example, the proposed method is used to carry out a 4/6 pole winding design and experiment validation. The results show that the motor efficiency is generally the same under the two speeds, which verifies the feasibility and effectiveness of the proposed design method.