Summary

 

This article focuses on the use of easy-drive CV3100 series 280KW inverter to drive a 250KW 8-pole asynchronous motor.

 

Keywords: gas station, frequency converter, compressor, PLC, touch screen

 

I. Introduction

 

Compressors are widely used in current industrial plants. According to the different compression media, compressors can be divided into many types. Air compressors are the most common type. As an important power equipment, air compressors are widely used in machinery manufacturing and chemical engineering. , Cement and building materials, mines, power plants, transportation construction, and many other fields, and the compressor introduced in this article is mainly used to compress natural gas. By compressing and boosting natural gas, the compressed natural gas is used to refuel cars. The easy-to-drive CV3100 series 280KW The frequency converter drives a 250KW 8-pole asynchronous motor to compress natural gas.

 

2. Work flow

Gas filling process: Obtain the gas source from the pipe network to distribute, separate, buffer, and meter the incoming natural gas. It needs to be equipped with gas valves, pressure regulators, flow meters, intake separation filter buffer tanks, and the drying system The water in the natural gas is deeply removed by molecular sieve to ensure that the leakage point of the finished product meets the requirements. Next, the dried mortgage natural gas is sent to the compressor to be pressurized to 24 MPa, and the pressurized and dehydrated product gas is sent to the car in priority order. Direct charging or supplying gas to high, medium and low pressure gas storage tanks can achieve the purpose of saving energy and ensuring the pressure of the high pressure gas storage system. The exhaust gas recovery system recovers the discharged natural gas from the gas filling station to save energy and environmental protection.

 

4. On-site debugging analysis

 

At the beginning, the customer reported that the machine showed ER09 failure when it was powered on and running for a period of time, and the fault current was about 1000A. After arriving at the site, the customer was allowed to run the machine and the machine did have an ER09 fault during the operation. The fault current was consistent with the customer’s reflection. This fault was observed Later, it was discovered that there was a problem with the customer’s external PLC program. After the machine was running for a period of time, the PLC program incorrectly issued a stop command. At that time, the inverter would stop during operation, and the customer’s deceleration time was set to 10S (over Short), which caused the machine to suddenly receive a stop signal to stop during operation. Due to the short deceleration time of the customer during the shutdown process, the mechanical inertia was large, which led to ER09 failure, and the machine's shutdown process was changed to free shutdown. After the machine received the stop command from the external PLC, the machine automatically stopped without ER09 failure, and then the equipment of the machine was started under pressure. There was a pressure of about 40 kg in the compressor pipeline, which caused the machine to skip ER09 failure when it started. The fault current of the machine is 980A, the fault frequency is 6.32HZ, the P0.16 of the machine is modified to 3, the machine is started, the machine fails, the fault frequency is 6.16HZ, the fault current is 1004A, try to modify P0.17 to 10, and the machine is running, the fault frequency is 5.89HZ , The fault current is 1106A, then continue to try a variety of V/F curve parameter settings, the ER09 fault still appears when starting, and finally try the vector control method, input the current, speed and other related parameters of the machine to the inverter, let The machine self-learning, running the machine more than 10 times, the machine no longer has ER09 failure, the maximum current of the monitoring machine fluctuates between 600-700A, and the machine debugging is successful.

 

5. On-site application

6. Summary

 

After using the inverter, the starting current of the compressor is reduced, and the current during loading rises smoothly without any impact; at the same time, the output pressure is stable, which improves the production efficiency and product quality; the amount of maintenance of the equipment is reduced in the future, and the starting current of the compressor is small , Less than 2 times the rated current, the loading and unloading valve does not need to operate repeatedly, the energy-saving control cabinet controls the compressor to automatically adjust the motor speed according to the air consumption, the operating frequency is low, the speed is slow, the bearing wear is small, the service life of the equipment is extended, and the maintenance workload is reduced; and At the same time, the inverter has protection functions for undervoltage, overcurrent, overload, overheating, and lack of equivalence, making the machine run reliably and smoothly.