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对新型电动自行车的关键动力部件-直流无刷电机作为深入的剖析与设计。本文所介绍的电动自行车中使用的直流无刷电机,纱参考英国Patscentre国际实验室协作设计产品,采用全电子操纵系统,电动自行车的最高时速可达25km/h,一次充电行程为64km。该电机的功率为350W,重6kg,具有自译电与过压过流全保护功能,效经可达85%,性能综合指标远优于传统的以有刷电机为动力的电动自行车。 相似文献
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目前已有不少空调厂家生产采用直流无刷电机风机盘管的产品,然而经过多年的市场推广,直流无刷电机风机盘管仍未能取代传统交流电机风机盘管成为市场主流设备。现通过对直流无刷电机风机盘管与传统交流电机风机盘管的各方面对比,找出直流无刷电机风机盘管的技术经济优势,从而为暖通空调工程节能减排设计提供新的选择。 相似文献
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基于AVR单片机的直流无刷电机智能控制系统设计 总被引:1,自引:1,他引:1
分析目前直流无刷电机控制器的现状,设计了一种直流无刷电机通用的控制系统,通过开关选择有位置传感器或者无位置传感器控制模式,实现了相同额定电压额定功率的直流无刷电机控制器的通用,并可通过RS-232与PC机通信方便上位机对电机运行状况进行监控,并通过24 V,220 V两种额定功率的电机的实际运行,验证了系统的可行性. 相似文献
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针对有传感器无刷直流电机的体积大、受环境影响等缺点,本文对无位置传感器直流无刷电机控制进行了相关的研究,根据无位置直流无刷三相电机的基本工作原理和电机转子反电动势的过零变化规律,结和PWM控制技术和电机绕组反电动势检测技术,采用DSP控制器设计无位置传感器直流无刷电机控制电路和控制方法,实践证明本设计结构简单,运行稳定可靠. 相似文献
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龚文资 《中国制造业信息化》2011,40(17)
介绍了一种电动自行车的反充电装置。通过采集电动自行车的车速信号及车辆制动信号,并由电子控制器控制电动自行车的充电装置,可实现电动自行车在超速或制动时,将车辆行驶的部分动能转化为电能,对蓄电池进行反向充电,从而提高了电动自行车的单次充电行驶里程及车辆的安全性,延长了蓄电池的使用寿命。制动时动能转化为电能也增强了制动效果,提高了电动自行车的制动性能。 相似文献
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龚文资 《机械设计与制造工程》2011,(9):48-49,54
介绍了一种电动自行车的反充电装置。通过采集电动自行车的车速信号及车辆制动信号,并由电子控制器控制电动自行车的充电装置,可实现电动自行车在超速或制动时,将车辆行驶的部分动能转化为电能,对蓄电池进行反向充电,从而提高了电动自行车的单次充电行驶里程及车辆的安全性,延长了蓄电池的使用寿命。制动时动能转化为电能也增强了制动效果,提高了电动自行车的制动性能。 相似文献
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本文用实验测试与理论分析的方法研究E. O. T. S. 电影经纬仪在工作过程中由于水平度盘方位角位置偏移而造成的误差,并提出消除或减少误差的方法.文章内容可提供电影经纬仪总体设计参考. 相似文献
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Russian Engineering Research - Attention focuses on determining the deformed state of the workpiece in free channel extrusion. The formulas obtained permit calculation of the accumulated strain at... 相似文献
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Two high molecular weight polymers, polyvinylpyrrolidone (PVP) and hydroxyethyl starch (HES), have been used as cryoprotectants for preparing specimens to be freeze fractured. Solutions of 25% (w/w) suppress the formation of intracellular ice in single cells and tissue blocks from both plants and animals to the extent that fine structural details of the cell can be elucidates. The mode of action of these cryoprotectants, together with the structures they reveal and the peculiar advantages attached to their use, is discussed. 相似文献
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This review summarizes our current knowledge of the ultrastructure of the human neurohypophysis and includes comments on its anatomy, physiology, and embryology. The neurohypophysis represents a unique tissue having neural and endocrine characteristics and possessing ultrastructural features distinct from those of conventional endocrine organs such as the anterior pituitary, thyroid, pancreatic islets, etc. In contrast to these glands, the neurohypophysis is composed of the processes of mature neurons. As such, it is not capable of synthesizing hormones but only of their storage and release. Neurosecretion is one of the most exciting areas of neuroendocrinology and, although spectacular progress has been achieved in elucidating the process, a number of aspects are incompletely understood. Recent evidence indicates that the magnocellular nuclei of the hypothalamus, the anatomic origin and functional basis of the neurohypophysis, produce not only vasopressin and oxytocin, the so-called "neurohypophyseal hormones," but a number of other biologically active peptides as well. The physiologic function of these substances is largely unknown but they may be of profound importance in endocrine homeostasis. Based on these novel findings, the role of the neurohypophysis in endocrine regulation has to be re-evaluated. 相似文献