Ⅰ. Application overview of Renle high voltage inverter
The Gansu Jingdian large-scale pumping station project uses the RNHV series intelligent high voltage produced by Shanghai Renle Frequency converter, this product adopts power unit series technology, stacked wave boost, and isolation transformer provides independent phase-shifting power. By changing the number of series units, the power unit adopts the AC-DC-AC method to obtain different direct output voltages. , To meet the needs of users for speed regulation and energy saving of different motor loads. At the same time, in order to minimize the construction period of the installation and transformation of the speed control system, the inverter adopts an integrated design concept, consisting of a transformer cabinet, a power cabinet, a control cabinet and a bypass cabinet (optional), and the user is directly connected to the input , The output cable is ready to use, convenient and fast.
Ⅱ, the advantages of inverter-driven motors compared to industrial frequency-driven motors
1. Small impact on the grid and motor:
When the motor is started at power frequency, its starting current will be as high as 6-10 times the rated current, which is likely to cause an impact on the power grid. At the same time, frequent power frequency starting of the motor is likely to damage the motor.
The starting current of the inverter is generally less than the rated current of the motor.
The limit is less than 200%.
2. RNHV high voltage frequency conversion series products have the characteristics of large starting torque, good adaptive characteristics, strong stability, and large overload margin.
3. Energy saving and cost reduction: the use of frequency conversion can effectively reduce the capacity of the transformer, and at the same time according to the frequency conversion，The speed regulation function of the device can effectively save energy and reduce emissions.
Ⅲ, the advantages of the application of Renle high-voltage frequency conversion speed control device Gansu Jingdian large-scale pumping station
1. The special high-voltage frequency conversion speed control device for Renle water pump is a high-voltage frequency conversion speed control device specially developed and designed by Renle for the load system of the water pump industry. This product integrates international excellent power electronic technology and vector control technology, and is not only compatible with international high-end frequency conversion The speed control device has the same excellent control performance, and also combines the characteristics of China's use environment, especially for the application field of the pump system. Many special measures have been taken to make it in the product reliability, environmental adaptability and customer personalization. All aspects can fully meet the various needs of pump applications.
2. The special high-voltage frequency conversion speed control device of Renle series water pump adopts the unit module series multi-level technology, which belongs to the voltage source inverter, and the power unit adopts the AC-DC-AC method, which is highly reliable and easy to operate.
The grid voltage is isolated and phase-shifted by the transformer to supply power to the power units. Each power unit is a single-phase AC-DC-AC voltage inverter. The units are connected in series to form a three-phase variable frequency power supply to power the high-voltage motor. According to the number of series units, the products are divided into 6kV and 10kV series. The main transformer adopts a phase-shifting rectification method with high input power factor, and the input voltage and current harmonics meet the strictest harmonic distortion requirements of IEEE519-1992 and GB/T 14549-93 for voltage and current. No need for any power factor compensation and harmonic suppression devices. The inverter output adopts multiple PWM technology, the output is almost perfect sine wave, no need to add output filter. The motor harmonic loss is small, the torque ripple is small, and there is no obvious motor noise. The motor does not need to be derated for use. The output dv/dt and common mode voltage are small, and there is no additional electrical stress damage to the motor.
3. Technical characteristics of Renle high voltage frequency conversion speed control device
1) The frequency conversion device adopts the latest design and manufacturing technology, and the internal components adopt high-quality imported components, which have a long service life and the most simplified system design, which improves the reliability of equipment operation and ensures the quality of the entire inverter;
2) The high-performance controller integrates DSP, FPGA, CPLD, and PLC devices with clear division of labor, safety and reliability.
3) The built-in PID regulator and fuzzy control regulator are integrated and designed for closed-loop control, and an external regulator can also be used for closed-loop control.
4) The remote communication monitoring interface of the controller system is RS232/RS485, which can flexibly support communication protocols such as Modbus and Profibus.
5) When the undervoltage of the high-voltage main power supply reaches 65%, it will not stop, and the inverter will automatically derate to run. After the voltage returns to normal, it will automatically return to the original set speed.
6) Adopting new control technology, superimposing controllable high-frequency components on the output voltage vector through vector algorithm, so that the motor produces greater resistance torque, speeds up the braking of the motor, and greatly reduces the speed reduction time.
7) The power grid can be restarted automatically after a momentary power failure.
8) Complete power unit protection and system protection, accurate fault diagnosis and positioning, and complete historical fault records and operation records.
9) The PCB board automatic welding production line has greatly ensured the quality of the PCB board, and truly grasped the quality firmly in their own hands.
The above technical characteristics have greatly improved the performance and reliability of the product, and some of the performance has been similar to the products of internationally renowned manufacturers.
4. Special personalized design for water pump
○ Vector open loop/closed loop control mode
○ Meet periodic load requirements
○ Satisfy the flow requirement of variable speed adjustment of water pump
○ Meet system speed stability requirements
○ Meet energy saving requirements
5. Renle water pump special high-pressure frequency conversion speed regulating device has unique technical advantages in water pumps:
1) The vector control method is adopted, which has high control accuracy and fast response speed, which effectively improves the efficiency of the pump, reduces valve damage, and meets the requirements of safe operation of the pump load;
2) The hardware configuration is high, the overload capacity is strong, and the 2 times overload can last for one minute, which can meet the periodic overload needs of the internal mixer;
3) Operation method, providing a sufficiently high starting torque, according to different production processes, by directly adjusting the motor speed to achieve energy saving, reduce the wear of the main equipment and corresponding auxiliary equipment, make the equipment maintenance cycle longer, and extend the equipment operating life;
4) Almost no high-order harmonics, no pollution to the power grid, no damage to the motor, no need to configure a grid filter device, improve the power factor to 0.96, and reduce reactive power loss;
5) With the motor soft start function, reduce the motor starting current, reduce the motor start impact, and reduce the operating noise;
6) Using carrier wave technology, the water pump shaft system can hardly feel the pulsation torque, reduce the vibration of the water pump equipment, reduce the heating of the equipment, and extend the life of the equipment;
7) Abundant and changeable mechanical characteristic curves, which can realize stepless speed regulation, meet the technological requirements of the water pump, and meet the demand of variable speed regulation flow;
8) Integrate a variety of on-site control methods, flexibly configure corresponding control methods according to different site needs, and have large software storage space and strong scalability;
9) System integration design, easy to use, users only need to provide cable wiring;
10) The trigger adopts the form of optical fiber, and the high and low voltage in the cabinet are completely isolated, with good safety and strong anti-interference ability;
6. Bring benefits to users:
1) Cost saving: Back-end automatic control through a dedicated communication protocol reduces wiring and equipment costs.
2) Energy-saving effect: The on-site water pump maintains the water level balance of all pumping stations through variable frequency adjustment of the flow rate, reducing frequent startup, and the energy-saving effect is about 18%.
3) Extend the service life of the equipment: reduce the impact on the power grid and the motor when the pump is started, the main equipment and corresponding auxiliary equipment (such as bearings, pumps, etc.) wear less than before, the maintenance cycle is longer, and the equipment operating life is extended.
4) Reduce on-site noise: The noise is greatly reduced, the working environment conditions are improved, and the on-site operators have responded well.
5) Improve power factor: When the original motor is directly driven by industrial frequency, reactive power compensation is used, and its actual operating power factor is 0.92. After adopting the high-voltage variable frequency regulation system, the power factor on the power supply side can be increased to above 0.96, and the reactive power can be greatly reduced without the need for reactive power compensation devices, meeting the requirements of the power grid, and further saving the operating costs of upstream equipment.
