With the continuous improvement of environmental protection requirements, desulfurization technology is increasingly widely applied in the industrial field. As a key piece of equipment in the desulfurization system, the performance and development of desulfurization fans play a crucial role in achieving efficient desulfurization and reducing pollutant emissions.
The early desulfurization fan technology was relatively simple, with low performance and efficiency. Moreover, when high-power motors were directly started, they would generate significant current surges. These surges not only caused impacts on the power grid but also potentially led to the risk of other loads shutting down. Frequent starts during use greatly reduced the service life of the motors.
1.Customer demand
High-power loads can generally be started by common methods such as solid-state soft start or series water resistance. Currently, the optimal starting scheme is driven by a frequency converter. A certain electrolytic aluminum customer in Xinjiang has four desulfurization fans that adopt the traditional starting method. The current is 5 to 8 times the rated current of the motor, which seriously lowers the grid voltage and also causes the risk of other loads shutting down. There is an urgent need for upgrading and optimization. The requirements are as follows:
The frequency converter, as a soft starter, successively starts four 3250KW motors. After the start-up is completed, the frequency converter exits the operation.
The site requires that the two frequency converters serve as backups for each other and both can meet the one-to-four requirement.
A connection cabinet is set between the two busbars on site. When the connection cabinet is in the closed state, one frequency converter is allowed to drive four units to start. If the connection cabinet is in the open state, only one frequency converter is allowed to drive two motors for each section of the power supply.
The frequency converter can start any load according to production needs and switch to industrial frequency operation without disturbance, achieving energy conservation and high efficiency, no voltage drop during startup, and meeting process requirements, etc.
2.FGI scheme
According to the customer's requirements, FGI has tailored a two-to-four disturbance-free switching solution for the FD5000 medium voltage drive. This solution has the following advantages:
The FD5000 control system adopts a multi-core control system of DSP+FPGA+ARM, and uses a sensorless vector control mode. It features high control accuracy, fast dynamic response and large low-frequency output torque.
The solution is tailor-made, featuring excellent low-frequency compensation performance. By sampling advanced four-wheel drive compensation and low-frequency oscillation suppression algorithms, it offers outstanding output performance at low frequencies, meeting the requirements for heavy-load startup. According to production needs, the frequency converter can switch to any load without disturbance, and the startup is not restricted by time or frequency.
Four switching cabinets are controlled by FGI's FD model PLC. A one-standby and one-use scheme is designed. Two frequency converters can start any four fans. There are mechanical interlocks and program logic interlocks among the four switching cabinets. The operation is simple, safe and reliable, and the degree of automation is higher.
Through the "frequency and phase locking" control technology, the motor can smoothly and shock-free switch between frequency conversion and power frequency. It is suitable for one-to-many or large-capacity motor soft start scenarios.
3.Customer revenue
The FGI5000 two-to-four non-disturbance switching system enables one frequency converter to start any motor at will, allowing for multiple consecutive starts with minimal impact on the motor, machinery, and power grid.
Through variable frequency start-up without disturbance switching, the soft start of the motor and load is truly achieved, avoiding the impact on the power grid and motor, effectively extending the service life of the equipment, reducing the failure rate of the motor and equipment, and saving costs for customers. The traditional start of the way will cause instantaneous power fluctuations, may be the cause of equipment downtime in production brings to the production and operation. The starting current through the frequency converter is about 0.5 times that of the motor current, ensuring the stability of power supply.
4.End
The successful application of the FGI FD5000 MVD two-to-four solution in the desulfurization fan has fully met the customer's process requirements, achieved energy conservation and cost reduction, and is stable and reliable. In the future, Invt will continue to enhance the energy-saving level of load equipment in the non-ferrous metal industry, significantly reduce production and maintenance costs, increase the degree of automation and production efficiency, create high-quality solutions for more enterprises, and work hand in hand with all parties to promote the continuous progress and development of the industry.
