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When does one need to "tune the current loop"?

RichB
Intellectual 585 points


Hi all

How does one know when one should tune their current loop rather than leave the Ip/Iq gains as automatically chosen?

What are they effects of an untuned current loop?

Cheers

Rich

  • 0
    TI__Guru** 119670 points
    the current loop for InstaSPIN-FOC and -MOTION is tuned based on the Rs and Ls in user.h (or after you go through motor ID).
    this is well tuned.

    the cases where we have seen a need for other tuning
    - very low speed, high load control. increasing the Kp can be helpful.
    - motors where Rs is changing quite a bit. if you are changing the Rs into FAST using RsOnline it may also be useful to recalculate the gains for the current controllers

    you really have to test to see if the tuning meets your torque response goals.
  • 0 in reply to ChrisClearman
    Expert 1620 points 
    

    ChrisClearman said:


     - motors where Rs is changing quite a bit. if you are changing the Rs into FAST using RsOnline it may also be useful to recalculate the gains for the current controllers

    

    

    When use RsOnline,the Kp and Ki will be refreshed all the time,so if I set a new Kp value, this value will be replaced by recalculation result immediately.How to tune it ? Need I add code: new Kp = recalculation Kp * S? (S is a scale factor,such as 1.1 ro 1.2 or 1.3 or ... )           
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    

	            
                	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
			
		
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
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                          TI__Guru**
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    "When use RsOnline,the Kp and Ki will be refreshed all the time"
    
are you sure about this? I haven't run lab07 in awhile, but just looking through the .c I don't think this is the case.  Rs is updated into FAST...and if you manually change a gain in gMotorVars it will update into the controller...but I don't see the gains getting recalculated with new Rs values anywhere else in the code.
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    

	            
                 	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
			
		
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
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