In extreme high lemperature environment, the heat dissipation efficiency of water cooling system for converter of MW-grade wind power generators designed for normal temperature environment decreases, which will cause the converter to be overheated and to operate incorrectly. An improved cooling system with an air cooling refrigeration unit combining vapor-compressed refrigerator in scries with normal water cooling system is proposed. The. Heal exchange between the main waler cycle of the converter and the refrigeration unit is realized through a cold storage water lank and an electric three-way valve, which could satisfy the heat dissipation requirement under extreme high temperature environment. When the environment temperature is above 45 centigrade degree and the thermal load is of 82 kW, the return waler temperature will be below 46 centigrade degree. The heat release of the air radiator is only half of the output under normal temperature hecause of the refrigeration unit. In addition, because of the closed water cycle, water and energy are conserved in the proposed water cooling system.%在常规环境温度下使用的兆瓦级风力发电变流器水冷系统在极端高温环境时会出现散热量衰减,导致变流器温升超标,不能正常工作.提出在常规变流器水冷系统的基础上串联空气压缩机制冷的风冷制冷设备,通过水箱蓄冷和电动三通阀开闭,实现变流器主水循环与制冷设备换热,满足极端高温环境风力发电变流器散热降温的要求.这种新的水冷系统在环境温度超过45℃、投入热负荷82 kW条件下,热负荷回水温度低于46℃,并且由于制冷设备的运行,空气散热器散热量比常温下减少1/2.由于该类水冷系统为密闭式水循环,节约水源,而且通过系统控制实现了水冷系统的节能运行.
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