Extra-high-voltage silicon carbide converter valve cooling system

Abstract

The invention provides an extra-high-voltage silicon carbide converter valve cooling system. The extra-high-voltage silicon carbide converter valve comprises a silicon carbide double valve formed by asilicon carbide converter valve; the cooling system comprises a primary cooling system and a secondary cooling system; the primary cooling system comprises a condenser and a heat exchanger assembly provided by the condenser; and the secondary cooling system comprises a secondary cooling medium outlet pipe, a secondary cooling apparatus, and a heat exchanger and a circulating pump which are provided by the secondary cooling apparatus, and a secondary cooling medium return pipe. The cooling system provided by the invention is high in voltage resistance, simple in structure, high in operationalreliability, low in cost, high in cooling efficiency, high in environment adaptivity, safe in equipment operation, convenient to maintain and high in economic efficiency; the phase changing cooling medium circulation power is provided by heat loss of components, such as a silicon carbide transistor, a damping resistor and the like, so that external power is not needed; and the whole system forms an independent self circulation system and is convenient to maintain.

Description

technical field [0001] The invention belongs to the field of ultra-high voltage direct current transmission converter valves in power electronics, and specifically relates to a cooling system for ultra-high voltage silicon carbide converter valves. Background technique [0002] UHVDC transmission is currently the only advanced transmission technology that can efficiently transmit 10,000 MW-level electric energy to a distance of 2,000 kilometers. It has the advantages of large transmission capacity, long distance, high efficiency, low loss, and small footprint. District power transmission has always played an important role. [0003] The converter valve is the core equipment of DC transmission. At present, the core component of the converter valve is the thyristor. Since the voltage of the converter valve is as high as hundreds of kilovolts and the current is as high as several thousand amperes, the thyristor valve with semiconductor silicon as the basic material There will ...

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Problems solved by technology

[0003] The converter valve is the core equipment of DC transmission. At present, the core component of the converter valve is the thyristor. Since the voltage of the converter valve is as high as hundreds of kilovolts and the current is as high as several thousand amperes, the thyristor valve with semiconductor silicon as the basic material will generate huge power loss

Moreover, the performance of thyristor switches based on silicon devices has approached its theoretical limit determined by material characteristics with the improvement of its structural design and manufacturing process. very limited

[0004] In addition, the cooling method of UHVDC converter valves has undergone a transformation from air cooling and oil cooling to the current water cooling method. Compared with air cooling and oil cooling, water has the highest thermal conductivity, the largest specific heat capacity, and the strongest convective heat transfer capacity. However, due to the high pressure resistance of silicon carbide thyristors, the internal thermal conductivity and power density are much higher than those of silicon thyristors currently used, and the existing water cooling methods have low cooling efficiency, complex water treatment systems, uneven temperature distribution, and electrical corrosion. A series of problems such as scaling and insulation failure caused by leakage can no longer meet the cooling requirements of silicon carbide thyristor converter valves

[0005] Phase change cooling is a new and efficient cooling method. However, the existing research mainly focuses on the field of generator technology, power tubes and GTO inverters, and almost no phase change cooling is applied to UHVDC converter valve devices. The selection of phase change cooling medium is the key to phase change cooling technology. It is necessary to study the heat flow characteristics, electrical insulation, material corrosion and environmental friendliness of phase change cooling medium in depth.

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