Microgrid DC-DC Converter Duty Cycle w/ Microgrid

Hello, I am using the "Green Hydrogen Microgrid" model, but I'm trying to change the battery DC-DC Converter to run off of a duty cycle or PWM. The pulse was created to be 1's and 0's when the solar power is below a ceritian range. However, when I change the battery/storage connected DC-DC converter from the existing current reference to duty cycle and then connect my pulse, I run into multiple problems. If I use the buck boost converter, then I recieve various errors such as "input voltage must be greater than or equal to zero". Is there a way I can get this model to run with the battery connected DC-DC converter utilizing a duty cycle pulse. Thank you for the help.