区域水资源复合系统可持续利用演变轨迹研究

从分析感应电机的铁损耗入手,给出了转子铁损耗等效电阻随转差率的变化关系.通过研究转子铁损耗在整个铁损耗中所占比例和同步角频率的关系,指出在低速区转子铁损耗对电机运行效率有着显著的影响.建立了考虑转子铁损耗时感应电机的损耗模型.利用拉格朗日优化算法,推导出感应电机在矢量控制下稳态运行时效率最高的控制条件.实验结果证实,所建立的损耗模型在全速范围内都有着较高的准确度,所推导的最大效率运行条件也是切实有效的.

Study of sustainable evolution track of regional water resources complex system

Regional water resources complex system (RWRCS) has been developing with different S-type patterns. Due to the linearity of Logistic(L) model, L curve can not express the diversity of evolution pattern, so the Richards(R) model is introduced which is more flexible to describe the evolution diversity of RWRCS. By analyzing the evolution characteristics, the evolution patterns are classified into three types: symmetrical developing type (SDT), rapid developing in earlier stage type (RDET) and rapid developing in later stage type (RDLT), and it is considered that the prophase in peak stage of RDET and the anaphase in starting stage of RDLT are also sustainable utilization optimum timing of RWRCS. Furthermore, the long-term process of the sustainable evolution is explored. It is indicated that the long-term process of the sustainable evolution is a combination of continuous gradual change and discontinuous fluctuations. In the end, Dalian City is taken as an example to research evolution track of RWRCS. The results show that the evolution process of Dalian water resources complex system(DWRCS) exhibited obvious S-type in 1980-1988 and 1990-1998, and the evolution patterns of these two passages were RDET. In 1980-2007, the fluctuations existed in the gradual change process, but the evolution process of DWRCS basically corresponds to S-type, and the evolution pattern is RDLT.