1. Brief introduction of permanent magnet variable frequency direct drive system for mill

The permanent magnet variable frequency direct drive system for mills is independently developed and produced by Jingji Technology Co., Ltd., with permanent magnet variable frequency drive products as the core technology. Mainly suitable for various mills with edge drive and center drive. Compared with traditional drive products, the permanent magnet variable frequency direct drive system has direct drive low speed, large torque, maintenance-free, high efficiency and energy saving, convenient installation, stable operation, compact structure, It has many advantages such as small footprint and long service life, adapts to various harsh working environments, and is the ideal driving product for various mills at present. At present, it is widely used in mining, coal, port, metallurgy, chemical, building materials, electric power, food and transportation fields.

2. Product composition

The frequency conversion permanent magnet direct drive system consists of a permanent magnet frequency conversion direct drive motor, a special frequency conversion control device, a system control device and a cooling device.

(1) Permanent magnet variable frequency synchronous motor

Permanent magnet variable frequency synchronous motors are excited by permanent magnet materials, and high-quality permanent magnet materials (NdFeB) are selected. Compared with traditional three-phase asynchronous motors, it has the characteristics of high power factor, long service life, high efficiency and energy saving, simple structure and reliable operation.

(2) Dedicated AC inverter

The frequency converter adopts direct torque control/vector control, which can realize precise control of torque. The inverter for PVD system is specially designed to match the start (brake) characteristics of permanent magnet variable frequency synchronous motors. It has the characteristics of high efficiency, superior electromagnetic compatibility, and strong environmental adaptability. It fully meets the needs of various working conditions and effectively reduces the need for power grids. Interference with surrounding equipment.

(3) Dedicated control box

The special control box for PVD system adopts modular design, distributed I/O control, and full network communication protocol, which minimizes the number of wiring and reduces non-action or non-action caused by poor contact. Support multiple communication protocols such as Ethernet, RS485, RS232, MODBUS, etc. The control box is equipped with a color high-definition touch screen, and the configuration screen content is comprehensive. In addition to monitoring all operating conditions of the PVD system, it also has alarms, fault shielding functions, real-time, historical data query functions, historical fault query functions, parameterized debugging and maintenance functions, Data remote upload function, etc.

(4) Special cooling device

The cooling device adopts the air-water cooling method. According to the heat dissipation characteristics of the system inverter and the permanent magnet variable frequency synchronous motor, independent, series and parallel cooling connections can be selected. Optimize the cooling effect. It is the guarantee for the safe and reliable operation of the PVD system.

3. Permanent magnet variable frequency direct drive system scheme for various mills

 

Figure 1: Permanent magnet direct drive system of edge drive cement mill

 

 

 

 

Figure 2: Permanent magnet direct drive system of central gearless cement mill

 

 

 

 

Figure 3: Permanent magnet direct drive system of edge-drive mine mill

 

 

 

 

Figure 4: Permanent magnet direct drive system of center gearless drive mine mill

 

 

 

 

 

Figure 5: Permanent magnet direct drive system of ceramic mill

 

 

4. Features of permanent magnet direct drive system for mill

4.1 High efficiency, high power factor

Without deceleration device, the mechanical efficiency is close to 100%.

4.2 Efficient area

The PVD system has high efficiency in the range of 20%~120% of the rated load of the conveyor. Under low load and low speed conditions, it has more advantages compared with asynchronous motor drive systems.

"Load-efficiency" comparison chart                                      "Load-power factor" comparison chart

4.3 More safe and reliable

PVD system uses permanent magnet direct drive technology, and the drive system has no intermediate transmission links. The system has few failure points, low vibration, low noise, and more stable and reliable operation. The PVD system adopts frequency conversion soft start (brake) technology, which has little dynamic impact on the belt conveyor when starting (brake), which improves the reliability of the belt conveyor and prolongs the service life of the conveyor.

4.4 Maintenance-free

There is no intermediate transmission link, and there are few maintenance components, which radically reduce operation and maintenance costs.

4.5 Intelligent control

The system has zero-speed full-torque output characteristics, realizing heavy load starting

Possess low-speed belt inspection function to realize frequency conversion stepless speed regulation.

Adopt direct torque control, double closed loop (speed loop, current loop) adjustment to achieve multi-drive power balance

The intelligent drive can adjust the conveyor speed according to the load to realize energy saving and environmental protection.

5, performance advantage comparison

Performance comparison	Asynchronous motor drive system	Electric excitation motor drive system	Permanent magnet variable frequency direct drive system
Drive composition	Water resistance cabinet + winding motor + gear box + coupling	Soft start cabinet + excitation cabinet + electric excitation synchronous motor + air clutch	Inverter + permanent magnet motor
Process adaptability	Constant speed operation, only suitable for a single working condition	Constant speed operation, only suitable for a single working condition	Variable frequency speed regulation to meet the requirements of variable loads
system structure	The system is cumbersome and the reliability is poor	The system is cumbersome and the reliability is poor	Simple system and high reliability
Aerodynamic performance	Poor startup performance, unable to start continuously	Start without load, but cannot start continuously	Soft start, high torque, continuous start
Maintenance	High failure rate and high maintenance cost	Low failure rate and low maintenance cost	Low failure rate and low maintenance cost
volume and weight	Large area	Large area	Small footprint
Transmission efficiency	Low transmission efficiency and high energy consumption	High transmission efficiency and low energy consumption	Direct drive, high transmission efficiency, low energy consumption
cost of investment	Low initial investment cost	Higher upfront investment costs	The highest initial investment cost

6. Analysis of customer return on product energy saving

7, application examples

8. Product industry operation report