Posted 19 Jul 2017 Hi All, I was wondering if any of you guys could help me about improving my load sharing application. At the moment it's very unstable and i can't see what i am doing wrong! Thanks. Details: I am trying to run a industrial chain conveyor using Torque control by Real sensorless vector control function of A700 Mitsubishi VFD. I have been following "Technical Note" which is provided by mitsubishi (see attached PDF). As described on technical note, i am trying to control 5 motors ( 1 X 2.2kW, 4 X 1.1kW) to share the load on this chain conveyor. Torque command (SV) and Motor Torque (PV) read from Master VFD and PID output (MV) of Q03UDE transferred to Slave VFDs over CC-link. i would appreciate any information and help you can provide, Many Thanks. Application_Technical_Note_Load_Sharing.pdf Share this post Link to post Share on other sites
Posted 20 Jul 2017 Not positive I can help but can take a look. I have a little experience with this. Are you able to post your projects PLC and VFD? More details on the problem you are experiencing as well. Share this post Link to post Share on other sites
Posted 21 Jul 2017 Hi All, If you are interested to have a go, you may find my programs below. Thanks. K-line torque control(mr PLC).zip K_-Line 310517.zip 1 person likes this Share this post Link to post Share on other sites
Posted 22 Jul 2017 So, I am not able to find a problem here. Hopefully someone else can help. isengineer, if you see this and do not mind doing so post the symptoms you had sent to me that may give a better idea of where to look for others. Good luck Share this post Link to post Share on other sites
Posted 27 Jul 2017 Symptoms are, On run signal all drives accelerating up to set frequency (30Hz) fine (i believe during acceleration and deceleration, torque control not exercised) Then master drive runs at 30Hz and slave drives continues to increase their speed. I know that this is happening because MV (which is my torque command for slave drives) is quite large. Maybe i need to adjust my PID parameters to make it less responsive! But what i don't understand, all 4 slave drives not running at same speed, even though same MV value driving them all! Because of this some section of the chain conveyor stretches and some sections bunched up. Ideally i need all drives to run at same speed ( apart from Sinew drive, because this one has a larger diameter drive wheel and it needs to run 0.96 times slower than the others) so i can keep line tension same on everywhere on the line but i need all 5 drives to share the load. Thanks. Share this post Link to post Share on other sites
Posted 15 Aug 2017 A bit late. I must admit I haven't tried the load-sharing function before, but I've ran torque controls. Do you also set the maximum speed limit for all drives (e.g. speed should never exceed master drive + e.g. 2%)? Unless you set a maximum speed limit, all drives will continue to increase speed "unlimited" until their torque is applied correctly. Share this post Link to post Share on other sites