VHDL codes for battery charge & discharge and Control startegy used in Hybrid system

Thanks for the reply, i am doing it using the power Electronics and simulation is done using powersim in Matlab, i am just curious if any one has done it in simulink, the model should control the battery charge and discharge from/to the DC-bus volatge , so always the bus voltage is constant, i make the model but the problem the DC-bus is not constant, i am sure it is type of PI controllers tuning, if you have come acros it it will be good help