1140V series of four-quadrant variable frequency converters for industrial applications is the series of high-power frequency converter developed by our company to meet the demands of high-power industrial users faced with speed control of asynchronous motor, frequency conversion asynchronous motor, synchronous motor and permanent magnet synchronous motor  in the industrial fields. It adopts the “equivalent three-level and four-quadrant variable frequency source and filter technique”, it has many advantages like mature technology, advanced performance, complete function, good quality, compact structure, low price, convenient use and good service, etc. 

The 1140V series of variable frequency converters for industrial applications is designed and produced by CenteRole (Dalian) Electric Transmission Technology Co., Ltd. It consists of the transformer panel and variable frequency converter panel. There is one dry type transformer for 18-pulse wave rectification, which is used for the star-triple conversion at primary side winding to adapt to the variable frequency output of 380V /690V  and 1140V .The variable frequency converter panel consists of the same three H-bridge power module and a filter. The rectification unit of power module adopts AFE four-quadrant rectification, which will benefit the power factor and the quality of current wave at the power grid side. The AFE four-quadrant rectification supplies the steady DC support voltage which is not affected by the network voltage and fluctuation of load. The inverter unit of power module adopts H-bridge inverter, three H-bridge are sharing the AC bus，three H-bridge are connected in star and the inverter line voltage will reach five-level. The output filter is optimized designed sine wave filter. Through the filter, the output voltage to the motor is sine wave. 

• It adopts the equivalent three-level technique, both making the electric power to transfer bi-directionally to meet the demand of motor electric operation and power generation operation，and to ensure high power factor and low current harmonic on power grid side. It also sufficiently meets the international and national standards and requirements.
• The rated capacity of frequency conversion equipment can be as high as 1600kVA under the output condition of 1140V.
• It adopts the AFE four-quadrant rectification, DC buses voltage are accurate and steady, can not be affected by the variation at both  the power grid side and  the load side, and the quality of inverter voltage can be guaranteed.
• It adopts the equivalent three-level technique, the quality of the electric energy of variable frequency converter output is very high, the voltage harmonic is very low.
• Easy to enlarge the power system.
• Can realize the prompt braking of motor assembling unit.
• Adopt the built-in temperature detecting element IGBT to conduct real-time monitoring for the temperature of each IGBT, and guarantee that the use is safe and reliable.
• Adopt the couple rupture disc DC supporting capacitor, the system is safe and the service life of capacitor is long.
• Adopt the customized annular heat pipe cooling solution, the efficiency of heat dissipation is high and safe and it is reliable.
• The whole power system consists of 2 panels, with a compact structure. The whole size is only 3530mm width, 2200mm height and 1600mm depth. 

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