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Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V
Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V
Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V
  • Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V
  • Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V
  • Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V

Aplicación del sistema de control electrónico de realimentación de frecuencia variable IPC en un cabrestante minero de 380 V/660 V

Este artículo describe principalmente la aplicación del sistema de realimentación de energía de frecuencia variable IPC, utilizado en cabrestantes de pozos. Este sistema emplea un inversor especial de la serie PH7 para la industria de elevación y equipos de realimentación de energía de alta resistencia de la serie PFH, y reconstruye el modo original de control de velocidad por resistencia en serie del rotor, lo que permite inyectar a la red la energía regenerada del motor de elevación.


1. Introducción

La elevación minera es una parte fundamental del proceso de producción minera. El mineral o carbón extraído de los distintos frentes de trabajo subterráneos se transporta mediante equipos de transporte a través de túneles subterráneos hasta el depósito subterráneo, y posteriormente se eleva a la superficie mediante equipos de elevación. El ascenso y descenso del personal, así como el transporte de materiales y equipos, requieren el uso de estos equipos. Constituyen el eje que conecta el sistema de producción subterránea de la mina con la zona industrial en superficie, y su importante función se ilustra con la metáfora de «la garganta de la mina», lo cual resulta muy apropiado. Como equipos de elevación minera de uso común, los elevadores o cabrestantes deben cumplir con altos requisitos de fiabilidad, seguridad y eficiencia. El sistema de control eléctrico de realimentación de frecuencia variable de la división de elevación de Jianeng Company se ha implementado con éxito en la renovación del cabrestante de la mina de plata Changce, en el condado de Yizhang, perteneciente a Yixin Industrial Co., Ltd., en la ciudad de Chenzhou. Este artículo ofrece una descripción detallada de su aplicación.

2. Requisitos de transmisión eléctrica para cabrestantes de minería

1. Características de carga del cabrestante minero

Cuando un objeto pesado se eleva, el motor necesita vencer diversas resistencias (incluidos el peso y la fricción del objeto), lo que constituye una carga resistiva.

When a heavy object is lowered, due to its ability to descend according to the acceleration of gravity (potential energy), when the gravity of the heavy object is greater than the frictional resistance of the transmission mechanism, the gravity (potential energy) of the heavy object itself is the driving force for the descent, and the motor becomes the recipient of energy, thus belonging to the power load.

2. Requirements for the Driver of Mine Winch Motor

① High starting torque and good speed regulation characteristics;

② Strong overload capacity;

③ At low frequencies, it can output a large torque and cannot slide when suspended;

④ When lowering, the motor generates a large amount of regenerative energy, and it is required to be able to handle the regenerative energy of the motor reasonably.

3. Disadvantages of traditional control systems for mine winches

① High energy consumption

The traditional speed control method for mine winches is the winding motor rotor series resistance speed control. This control system consumes a large amount of slip power on the resistors connected in series with the rotor (usually accounting for more than 30% of the total energy consumption), resulting in a significant waste of electrical energy. From both energy-saving and economic perspectives, it is not advisable.

② Poor speed regulation performance

The rotor series resistance speed regulation method belongs to graded speed regulation, and the decrease in speed is achieved through the energy consumption of the external resistance of the rotor. The most important thing is that the lower the speed, the softer the mechanical characteristics of the motor, and the smaller the output torque. Moreover, graded speed regulation has a significant impact on motors and mechanical equipment, resulting in unstable equipment operation, discontinuous speed regulation, easy derailment, and high failure rate. For the 24-hour continuous production mode of coal mines, there are significant economic losses.

③ Poor system reliability

Frequent opening and closing of contactors (contactors frequently open and close under high current conditions) often causes sintering of contactor contacts and burning of coils.

Inadequate protective measures can easily lead to motor burnout.

The C brake is subjected to significant impact, and the brake pads are severely worn, making it easy for the brake to not hold tightly and requiring frequent maintenance and replacement.

④ High maintenance costs

Contactors, wound motor rotor brushes, and slip rings often require maintenance and replacement, which is costly.

The reducer and brake are greatly impacted and often require maintenance.

The characteristics of the C rotor series resistance speed regulation method ultimately result in limited production efficiency (frequent failures in shutdown and maintenance states), heavy maintenance workload, and increased usage and maintenance costs.

4. Advantages of frequency conversion feedback electric control system for mine winch

① The frequency converter has good speed regulation performance, large starting torque, hard mechanical characteristics, and accurate positioning.

② The frequency converter runs smoothly, with minimal impact on the reducer and brake, reducing equipment maintenance and extending the service life of the hoist.

③ After using the frequency converter, there is no need to use contactors anymore, and the wound motor can also be changed to a squirrel cage motor without the need for maintenance of the brushes and slip rings

④ The frequency converter has high operating efficiency and has complete protection, monitoring, and self diagnostic functions for the motor and system. If combined with PLC control, it can greatly improve the reliability of the mine winch electrical control system.

⑤ The energy feedback function can feed back the regenerative energy of the motor to the power grid, greatly saving electricity.

3、 Application of IPC frequency conversion feedback electronic control system in energy-saving renovation of mine winches (380V)

According to the load characteristics and control requirements of the mine winch equipment, the main configuration of the variable frequency feedback electric control system is as follows:

 

project

parameter

Remarks

System frequency converter

PH7-04-075NDC

75KW/165A/380V

1 unit

System energy feedback device

PFH55-4

Rated current: 55A, peak current: 80A

1 unit

System PLC

Siemens S7-200

CPU224/AC/DC/Relay

6ES7 214-1BD23-0XB8


sku:
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Description

3. Energy saving transformation system for frequency conversion feedback of mine winch

After the transformation of the mine winch system, the motor of the mine winch lifting mechanism was infinitely variable speed, greatly improving the control performance of the lifting mechanism and reducing the huge impact on the motor and mechanical parts. At the same time, energy feedback will enhance the regenerative energy of the motor to be fed back to the grid, greatly saving electricity, reducing the ambient temperature of on-site equipment operation, and extending the service life of electrical equipment. The energy-saving renovation system has two control cabinets, consisting of a frequency converter and an energy feedback device PLC、 The specific functions of the contactor and other components are summarized as follows:

1. After the system transformation, the variable frequency feedback control mode of the motor can be freely switched with the original rotor series resistance power frequency control mode, and the two control modes are electrically interlocked to ensure the safety of the system operation.

2. After the system transformation, the original operation mode and habits of the mine winch will be retained, that is, the gear control and operation mode of the original cam controller will be retained. In this way, it will not affect the normal operation of the mine winch operator and ensure that the special equipment inspection of the mine winch is qualified.

3. The variable frequency feedback electrical control system of the lifting mechanism has multiple protection functions such as short circuit, overvoltage, overcurrent, phase loss, overload, and over temperature, to maximize the protection of the lifting mechanism of the mine winch.

4. The system adopts a frequency converter to drive the lifting mechanism motor. When the motor drives the potential load to be lowered, the motor will be in a regenerative power generation state. The energy feedback device will feed back the regenerated energy of the motor in the generating state to the power grid, ensuring the normal operation of the variable frequency system and greatly saving electricity.


4. System debugging

① Debugging of PLC programs and control circuits. After the equipment installation is completed, the control circuit is powered on and the main circuit is not powered on. Perform control circuit and PLC program debugging to ensure correct logic control of the control circuit and PLC, and normal operation of all components.

② Debugging of frequency converter.

Disconnect the mine winch motor from the reducer, and use V/F control mode for no-load operation of the frequency converter. Drag the motor to ensure stable and normal operation of the motor, and the output voltage and current of the frequency converter are normal.

Disconnect the mine winch motor from the reducer, and use a PG free vector control method for the frequency converter to perform rotational self-learning and obtain motor parameters. Then, the PG free vector control method is used for no-load operation, dragging the motor and adjusting the corresponding parameters to ensure stable operation of the motor. The output voltage and current of the frequency converter are normal.

Connect the winch motor to the reducer, and use PG free vector control for the frequency converter. Run the frequency converter with load to ensure stable motor operation.

③ Debugging of energy feedback device.

Conduct no-load and heavy load lowering tests on the mine winch, correctly set the feedback action voltage value of the energy feedback device, and ensure the normal operation of the frequency converter and energy feedback system.

④ The overall debugging and operation of the system.

The entire system undergoes overall testing to ensure that the mine winch is lifted and lowered without load, lifted and lowered under heavy load, the speed of each gear meets the requirements, the gear shifts are normal, and the frequency converter and energy feedback device operate normally. And conduct work and frequency conversion switching tests to ensure normal switching and normal power frequency operation.

4、 The Application Effect and Customer Evaluation of IPC Frequency Conversion Feedback Electric Control System in Energy saving Renovation of Mine Winches

El funcionamiento real del sistema ha demostrado que la aplicación del sistema de control eléctrico de realimentación de frecuencia variable IPC en la modernización para el ahorro energético de los cabrestantes mineros no altera su modo de operación original, y el freno de mano original prácticamente ya no se utiliza, simplificando así la operación. El sistema funciona de forma estable y fiable, con un excelente rendimiento de regulación de velocidad y un elevado par de arranque y par de salida a baja frecuencia. Al descender el mecanismo, el excedente de electricidad generado por la regeneración del motor se inyecta a la red, lo que supone un importante ahorro energético. El cliente está muy satisfecho con la eficacia del sistema de control electrónico de realimentación de frecuencia variable IPC en la modernización para el ahorro energético de los cabrestantes mineros. Tras las mediciones, el sistema de control electrónico de realimentación de frecuencia variable IPC permite ahorrar más del 28 % de energía eléctrica en comparación con el método original de regulación de velocidad por resistencia en serie del rotor del motor del devanado del cabrestante minero.

5. Conclusión

La aplicación del sistema de control electrónico de retroalimentación por conversión de frecuencia IPC en la transformación para el ahorro de energía de los cabrestantes mineros ha mejorado el nivel de automatización de estos equipos en la industria minera y ha acelerado la modernización de los equipos industriales. Ha desempeñado un papel muy positivo en el aumento de la capacidad productiva de la industria minera y en la garantía de su seguridad.

Más importante aún, el equipo de elevación minera pertenece a la maquinaria minera de gran escala, y su consumo energético representa una proporción significativa del consumo total de energía de toda la producción minera. En comparación con el sistema de control de velocidad por resistencia en serie del rotor del motor bobinado, el sistema de control eléctrico de realimentación de frecuencia variable permite un ahorro considerable de electricidad, reduciendo así los costos de producción y generando beneficios económicos para la industria minera.