1.Introduction

Port crane machinery and other transmission machinery compared to the inverter has more demanding safety and performance requirements. Both to meet the frequent start, stop, significant vibration and shock, a large overload capacity and a variety of harsh conditions of use; and to meet the characteristics of the power supply: a variety of harmonic components, sharp current, voltage changes, down to ensure that the constant torque smooth speed regulation, up to ensure that the full power output at high speed of the weak magnetic, and in the low frequency, the fundamental frequency and high frequency must have enough output torque, etc.; more importantly To meet the safety issues of port machinery.

In this case, NewSky developed vector control based four-quadrant high performance lifting inverter, which was successfully applied in Shanghai Port Group Zhendong Container Terminal Branch No.130 shore bridge, taking an important step for the localization of port crane equipment electric control system.

2.The 130th shore bridge renovation situation

The modified shore bridge number 130, located in the second phase of Waigaoqiao Shanghai Port Group Zhendong Container Terminal Branch, was manufactured by Shanghai Zhenhua Heavy Industry (Group) Co.

Figure 1 No.130 shore bridge of Zhendong Company

Table 1 Table of 130 shore bridge motor drive equipment

In this retrofit, the original brand PLC and LCL filter are retained, the original brand AFE and inverter are replaced, and the data exchange between PLC and inverter drive is changed from the original brand special SX bus to the common Profibus-DP communication. The control flow of the modified 130 system is shown in Figure 2.

Figure 2 Block diagram of 130 shore bridge system

The retrofitted new Timex electronic control system isThe retrofitted new Timex electronic control system is：

1 original brand PLC, add SX to Profibus-DP module1 original brand PLC, add SX to Profibus-DP module；

1 x AS510-4T0400 400kW AFE replaces RHC400-4C AFE1 x AS510-4T0400 400kW AFE replaces RHC400-4C AFE；

2 sets of AS520-4T0160 replace the original brand FRN160VG7S-4LC inverter, each driving 2 132kW hoist motors or each driving 8 sets of 18.5kW motors and 2 sets of 15kW carriage travel motors；

One AS520-4T0132 replaced FRN132VG7S-4A inverter to drive four 22kW trolley motors or drive one 55kW pitch motor.

The electrical control modification of No. 130 shore bridge was started on January 30, 2012 to February 4, 2012 to complete the installation and commissioning work, and was put into operation on February 5. The renovation site is shown in Figure 3 and Figure 4.

The main difficulties in the transformation process are as follows.

(1) Matching of original brand PLC and new Timex inverter control: holding brake control and dynamic performance, because it is lifting the container, so it requires enough torque to lift or put down the container even if the motor is at a very low speed, and there can be no slipping hook when putting down or lifting, otherwise it will bring serious safety problems.

(2) The use of the original brand LCL filter and the new time with the AFE problem

Table 2 NewSky AFE actual measurement data

(3) synchronous control of the car. The car is dragged by 10 motors, 8 of which are controlled by the same inverter and the remaining 2 are controlled by another inverter, and the motor power and gear ratio of the 8 motor units and the 2 motor units are not the same. To ensure the synchronous operation of the trolley, the master-slave control mode is adopted, and the speed of the master inverter is transmitted to the slave inverter through CAN bus to ensure the consistency of the final speed of the 2 inverter-driven motors of the trolley.

(4) Smooth start and fast braking of the trolley. 4 trolley motors are controlled by the same inverter, using closed-loop vector control to achieve smooth control of the motor.

(5) The pitch motor has not been used for many years. As the pitch motor situation was unknown before the transformation, the inverter ran after the transformation, and the motor failed to start. After many tests, the motor has long been damaged, and after replacing the motor, everything is normal.

(6) Communication problem. The original brand PLC does not support Profibus DP, using third-party SX bus to Profibus DP bus, debugging complex. Adopting the DP module designed by New Time, there were many problems with the original brand system compatibility at the beginning, resulting in communication false alarm failure. Later, by changing the PLC communication program and adding relevant accessories, the normal use of communication was ensured.

3.OperationOperation

AFE Converters 

The NewSky AS510 active front-end AFE features current harmonic reduction, bus voltage smoothing and reactive power reduction. In actual use, it has been operating stably so far, except for the communication failure during the commissioning stage. After testing, the DC voltage and feedback voltage output from the rectifier are stable under various different loads of the shore bridge, the voltage fluctuation is within the normal range, the voltage harmonics are less than 1.5%, and the current harmonics are less than 5%. Through the test data of various working conditions in the trial production stage, it meets the demand of AC and DC reversible conversion of 130 bridge crane. Figure 5 shows the AFE operation diagram.

Figure 5 Grid waveform

Inverter (AS520-4T0160 and AS520-4T0132)

The hoist and trolley inverters have not shown any hardware failure from the trial run so far, and the software operation is stable and reliable. Figures 6-8 show the weak magnetic waveform, master-slave synchronization waveform and hanging cabin protection waveform, respectively.

Figure 6 Lifting downward weak magnetic curve

Figure 7 Master-slave control waveform

Figure 8 Hanging cabin protection curve

In the trial production stage after the completion of the transformation, after several times of debugging and fine-tuning of the control software, the control software fault of the inverter has changed from 7 kinds at the beginning to a resettable fault with occasional speed deviation at this stage; so that the resettable fault of 1000 TEU per operation was 20.74 times in February at the beginning of the shore bridge operation, and dropped to less than 2 times per 1000 TEU per operation in March, April and May. After a fine tuning in May, the reset failure per 1000 TEU in June, July and August was less than 0.3 times. The decrease in the number of failures verifies the high reliability of the hardware and the accuracy of the control software of the new Sida inverter, the light sound and smooth current waveform when the hoisting motor is holding. From the use of 130 bridge cranes now, the new Systech inverter system meets the reliable use of this type of bridge crane. The data in Table 3 is from the statistics of Zhendong Container Terminal Branch before August 23.

Table 3 Operation data statistics table

4.Application Experience

In the first month of use, due to unfamiliarity with the terminal working conditions, especially the driver's operating habits are not well understood, there are more reset failures, as the project team between the two sides to deepen the communication, failures also less and less patronize the 130 retrofit project. From the transformation in February to the present 8 months of application effect, fully meet the 130 shore bridge operation requirements.

Through the actual load measurement, it shows that the electrical performance of the inverter meets the technical requirements of port crane electric control. Its main technical performance indicators are comparable with similar products at home and abroad, and some performance indicators are better than similar products at home and abroad. The stability of port lifting and handling, high production efficiency, reduce maintenance costs, reduce the labor intensity of workers plays an important role in achieving good economic and social benefits.