Application 1 of Chengdu Sunwoele Medium Voltage Series VFD (Variable-frequency Drive)

Chengdu Sunwoele Co.Ltd. has been committed to the development and application of medium-voltage VFD (Variable-frequency Drive) (voltage 660V~690V, 1140V) since 2003, and has accumulated rich experience in continuous practice and exploration . At present, the medium-voltage VFD (Variable-frequency Drive) products developed and produced have been successfully applied to urban water supply, electric submersible pumps, water injection pumps, kowtow machines in oil fields, main shaft fans, belt conveyors, and coal excavators in coal mines. (anti-riot) and other fields have achieved good economic and social effects. At present, our company can produce medium-voltage VFD (Variable-frequency Drive) products with a power range of 22KW~800KW, covering almost the application requirements of all industrial and mining enterprises.

1. Sunwoele medium voltage VFD (Variable-frequency Drive)

Main components and technical description:

1. Use a 4400V reverse voltage rectifier bridge;

2. The use of DC reactors reduces the input current harmonics and improves the power factor at the input end of VFD (Variable-frequency Drive);

3. The inverter module uses 3300V high-voltage IGBT, without IGBT series connection, the number of power devices is reduced, and the reliability of the system is improved. The new generation of modules has low loss and improves the efficiency of the whole machine;

4. The drive circuit uses optical fiber isolation transmission to realize long-distance drive and improve the anti-interference performance of high-voltage circuits;

5. It is designed with ±15% voltage fluctuation, can withstand instantaneous 250% impact current, and has large low-frequency torque, adapting to China's power grid and working conditions;

6. Strong current shock suppression ability, safe and stable operation when the load fluctuates in a large range;

7. The advanced SVPWM non-sinusoidal pulse width modulation technology is used to inject zero-sequence signals into the sine wave. Voltage Space Vector Pulse Width Modulation (SVPWM) is a non-sinusoidal modulation technology that injects an appropriate third harmonic into the sine wave. Its linear modulation is 15% higher than that of SPWM, and the output harmonics are small. The switching frequency is reduced, the switching loss is reduced, and the reliability and life of the system are improved;

8. It can suppress the transient overcurrent of the motor, and the transient impact current can reach 250%, which ensures that it will not trip under heavy load and will not affect production efficiency;

9. Perfect protection: overcurrent, overvoltage, overload, undervoltage, underload, phase loss, short circuit, overheating, etc.;

2. Explosion-proof VFD (Variable-frequency Drive) technology

The explosion-proof VFD (Variable-frequency Drive) jointly developed by Chengdu Sunwoele Co.Ltd. and other explosion-proof equipment companies uses high-efficiency heat pipes or other high-efficiency heat dissipation technologies, and its extremely low thermal resistance and high-efficiency heat dissipation performance make the heat dissipation of high-voltage IGBTs better Solution, the design maximum VFD (Variable-frequency Drive) power can reach 800kW/1140V. In view of the special environment of coal mine underground, the explosion-proof VFD (Variable-frequency Drive) not only adopts corresponding moisture-proof and anti-drip measures in the box structure, but also increases the creepage distance and electrical clearance in the main circuit as much as possible, and in the control circuit. , all control panels have taken special moisture-proof measures. The explosion-proof frequency conversion speed control device adopts the vector control method of Sunwoele HFV3000 series without speed sensor. The basic control idea of the speed sensorless vector control is to detect the excitation current (or magnetic flux) and torque current as the basic control quantities according to the input motor parameters according to a certain relationship, and control the motor stator winding voltage The frequency makes the excitation current (or magnetic flux) and the command value and detection value of the torque current consistent, and the torque is output, so as to realize the vector control. The VFD (Variable-frequency Drive) adopting the speed sensorless vector control method can not only be comparable to the DC speed regulation system in the speed regulation range, but also can control the torque generated by the asynchronous motor to ensure the low frequency (0.5Hz) operation The output of rated torque can reach 1.5 times.

〉Application of Sunwoele medium voltage VFD (Variable-frequency Drive)

1. Application on mine explosion-proof belt conveyor

Belt conveyors are the main transportation equipment for high-yield and high-efficiency modern coal mines. Belt conveyors have a variety of driving technologies, such as direct start, speed-adjustable hydraulic coupling, soft start, and AC frequency conversion drive. The schematic diagram of the belt conveyor is as follows:

At present, the belt conveyors in coal mines have higher and higher requirements on the driving technology. The basic requirements are:

(1) Simple control, good starting characteristics, good speed regulation performance, and large starting torque;

(2) energy saving;

(3) Reliable work and low maintenance;

(4) The price is moderate.

Explosion-proof VFD (Variable-frequency Drive) using speed sensorless vector control (SVC) can meet user requirements and will be the development direction of underground belt drive.