The hottest start market has a long way to go

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As a special equipment for national industrial production, lifting and transportation equipment is widely used in various industries. With the continuous improvement of the requirements of industrial production for the speed regulation performance of cranes, the traditional speed regulation methods of cranes are commonly used. Because the collector rings and brushes of wound rotor asynchronous motors are prone to failure, coupled with the use of a large number of relays and contactors, the amount of on-site maintenance is large, The failure rate of the speed regulation system is high and the comprehensive technical indicators are poor, which can no longer meet the special requirements of industrial production

in recent years, with the continuous development of frequency conversion technology, the performance of frequency converter is improving day by day. The mechanical characteristics of frequency conversion and speed regulation are hard, the speed regulation range is large, the speed regulation accuracy is high, the stability is good, easy to control and energy saving, and other characteristics of phenol oil processing, washing oil processing, coal asphalt high-end utilization industry, which can well meet the requirements of lifting equipment, such as safety, stability, reliability, good operability, reliability, maintenance free, etc, It has made a breakthrough and been widely used in the crane industry

at present, among many frequency converter brands, there are not many products that can fully meet the characteristics of the lifting industry. The main difficulty is that due to the particularity of the crane, the frequency converter for the crane must have some special properties: fast dynamic response to meet the requirements of the sharp change of the load of the crane in the hardness test; Wide range speed control capability, which can make the motor output peak torque of 2~3 times the rated torque near the low-speed section; It can withstand the current impact caused by the sharp change of potential energy load and ensure reliable operation in the continuous mechanical vibration environment; The regenerative energy of the motor can be reliably released during deceleration braking, and the current capacity as a braking unit needs to be larger; It has a highly reliable protection system. For the lifting mechanism, special attention should be paid to the control of preventing hook slipping immediately after the mechanical brake is released. The practice has proved that the control of hook slipping immediately after the brake or before the holding brake; It has a powerful monitoring system, which can realize the fault alarm and fault analysis of the system through the monitoring of various parameters

now take Delta vfd-c2000 inverter as an example to briefly introduce how to solve these difficulties. The FOC PG control application of delta vfd-c2000 inverter can obtain stable speed output and optimal dynamic response through the motor parameter learning function and speed feedback signal; It can accurately control the output torque within a wide range of 0.05hz~50hz; The current capacity is large, which can withstand the maximum 200% of the rated current impact; Unique energy recovery technology; The perfect protection system has stall protection function, which can prevent acceleration, deceleration and stall in operation. At the same time, it also has overcurrent, overvoltage, undervoltage and input phase loss protection, as well as over temperature, overload, overspeed, motor fault protection and other functions. C2000 has built-in PLC function and CANopen protocol, and can complete real-time data monitoring well in combination with modbus, PROFIBUS, DeviceNet and other high-speed communication networks

in 2009, the overall market scale of frequency converters in the lifting machinery industry was 1.26 billion yuan. With the continuous development and improvement of power electronic technology, they increasingly show excellent control and speed regulation performance, high efficiency, easy maintenance and other characteristics, coupled with the continuous decline in the price of frequency converters, frequency conversion speed regulation will become a preferred speed regulation scheme for lifting machinery, The market scale of frequency converter in the lifting machinery industry also expands the enterprises' value chain and production process to different countries and regions through networks

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