Battery Connected DC-DC Converter Duty Cycle from "Green Hydrogen 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 pulse. 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, 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.

[Sabin]

It appears that the DC-link voltage is going to negative values which will trigger an error. Can you provide a sample model?

[James Vrtis]

I have attached a copy of my model with an image of the solar and pulse generation over time. The pulse generated would control the duty cycle of the DC-DC converter. I've carried the signal over to the battery storage module but left it unconnected to prevent errors when starting the simulation.

[Sabin]

The model is missing CompressorMapSpeedLines.mat. Are you trying to use the PWM signal to control the DC-DC converter or the duty cycle? If you want to use the pulse that will slow down the simulation. If you preffer to use the duty cycle as a value between 0 and 1 (but not a pulse) that can be done without any impact to simulation speed.

[James Vrtis]

Yes, sorry I thought I resolved the compressor problem after attaching the slx file. I'm not sure how to save the imported Base Workspace variables from " ee_electrolyzer_grid_nh3.m" which contains the compressor data. I would be fine with either just to get the DC-DC Converter controled by this signal.

Answer 1

[Sabin]

It appears that there is an issue with the Signal Processing logic to compute the duty cycle. It is possible to configure the DC-DC converter to use duty cycle but the duty cycle is expected to be a value between 0 and 1 rather than a pulse. Duty cycle is a parameter that describes the proportion of time a PWM signal is ON versus OFF within a given period. Best to revise the algorithm for computing the duty cycle.