## 7 Conclusions  
In this paper, the temperature and loss characteristics under different magnetic loads and current densities are compared and investigated. The comprehensive effects of magnetic load and current density on temperature are further revealed. On the basis of the conclusions obtained, the temperature characteristics of the final scheme and the prototype are analyzed to verify the validity and feasibility of our conclusions. The key points are summarized as follows:  
1. When the stator magnetic flux density increases from 1.2 T to 1.6 T, although the temperature of each part of the motor increases, the highest temperature rise is only 9 \({}^{\circ}\)C, which appears at the stator winding. In addition, the temperature of the PM only increases by 2.7 \({}^{\circ}\)C. Therefore, an increase in the magnetic load does not cause a significant increase in the temperature for LSPMMs. 2. Case 1 and Case 2 have the same current density. However, compared with Case 2, the core loss of Case 1 increases by 639 W due to the higher magnetic load. In addition, in order to ensure the same back-EMF, the core length of Case 1 is shortened while increasing the magnetic load, resulting in lower copper loss of Case 1. The copper loss of Case 1 is reduced by 2757 W compared with Case 2, which is about five times the increase in stator core loss. Therefore, Case 1, with a higher magnetic load, has a lower temperature under rated load compared with Case 2. The winding and PM temperatures of Case 1 are 120.3 \({}^{\circ}\)C and 78.8 \({}^{\circ}\)C, respectively, and the temperature of the corresponding parts of Case 2 are 122.9 \({}^{\circ}\)C and 68.5 \({}^{\circ}\)C. Thus, for LSPMM design, an increase in the magnetic load may not lead to an increase in the temperature, because the core length will also be shortened, resulting in lower copper loss and the possibility of a temperature drop. Figure 22: Prototype. Among the four schemes, Case 4 has the smallest current density, but has the largest stator magnetic flux density and stator core loss. Compared with the other three schemes, the current density of Case 4 is reduced by 1 A/mm\({}^{2}\), 1 A/mm\({}^{2}\), 2.3 A/mm\({}^{2}\) in turn, resulting in a reduction in copper loss by 1510 W, 4267 W, and 6598 W, while the stator core loss increases by 625 W, 1264 W, and 1610 W, respectively. However, the temperature of Case 4 is the lowest. Compared with the other three cases, the stator winding temperature of Case 4 drops by 18.1 \({}^{\circ}\)C, 20.7 \({}^{\circ}\)C, and 48.8 \({}^{\circ}\)C. It can be summarized that although the stator core loss keeps increasing, the copper loss due to the decrease in current density decreases more sharply; thus, the temperature still decreases. Therefore, for LSPMMs, the motor temperature is significantly affected by current density. 4. After comparing the final scheme with the initial scheme, the final scheme with higher magnetic flux density and lower current density has a lower temperature. The stator winding temperature of the final scheme is 101.7 \({}^{\circ}\)C, and the stator winding temperature decreases by 21 \({}^{\circ}\)C compared to the initial scheme. In addition, the temperature performance of the manufactured prototype is also very good, and the error between the measured and calculated results of the temperature is only 2%. Therefore, in the design of outer rotor LSPMMs, lower current density and higher magnetic load can indeed lead to better temperature performance. Conceptualization, G.D. and Q.Z. ([PERSON]); Data curation, G.D. and Q.Z. (Qizheng Zhang); Formal analysis, Q.Z. (Qizheng Zhang); Funding acquisition, G.D.; Investigation, G.D. and Q.Z. (Qizheng Zhang); Methodology, G.D. and Q.Z. (Qizheng Zhang); Project administration, G.D.; Resources, G.D.; Software, Q.Z. (Qizheng Zhang); Supervision, Q.Z. ([PERSON]); Validation, G.D., Q.Z. ([PERSON]), T.P. and C.H. ; Visualization, Q.Z. (Qizheng Zhang); Writing-original draft, Q.Z. (Qizheng Zhang); Writing-review & editing, G.D., Q.Z. (Qizheng Zhang), C.H. and T.P.