How to generate first value for Kp, Ki of PID in current controller

How to generate first value for Kp, Ki of PID for Id,Iq in current controller.Now I put random values for initial kp,ki values.For Example ,For Many projects ,I put kp =1,Ki = 10.After that ,I have to tune using auto tuning method.So,Do you have any method or formula for generate initial value for Kp,Ki of PID in current controller.

[Sam Chak]

Can you show the mathematical model of the plant or system?

The initial values for the control gains can be generated when the nominal model is available.

How you want to tune them later to fit the control objectives is another story.

[Aquatris]

This depends on a lot of things. However if you know nothing about the system, there is no way to do this. You can try to follow certain PID tuning methods (ziegler nichols is the most popular for simple systems) but then you need to know the order of magnitude of your gains regardsless.

Answer 1

[Sabin]

It is possible to use pole placement as a starting point. If you can approximate the plant with a first order system, it is easy to compute the gains in MATLAB. See below an example for tuning the PMSM current controllers if we know the values of inductance L (can be Ld and Lq or same L depending on if surface or interior magnets) and resistance R. The only parameter we will need to define is the bandwidth.

% G(s) = 1/(L.s+R)=(1/R)/((L/R).s+1)

w0=Hz*2*pi; % bandwidth [rad/s]
zeta=1;     % attenuation
Kp=2*zeta*w0*L-R; % proportional gain     
Ki=Kp*(L*w0^2);   % integral gain 

[adhavan d]

can you tell how to calculate frequency which is used for calculating Bandwidth(w0)?

Answer 2

[MathWorks Motor Control Blockset Team]

Please refer to the following document page: Estimate Control Gains and Use Utility Functions.