Delay after applying "step time" for DC Boost converter with controller
Hi, currently I'm studying about DC-DC Boost converter with controller. After I applied the step time, the output voltage supposed to follow the step time, but there is some delay in the simulation results after I applied the "step time" in the step input block. Can someone help, why this delay occur? Please see the attached pictures. Thanks
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Please, share your model and I would be happy to have a look into it.
Hi, this are the models. I tried these examples.
1. https://www.mathworks.com/matlabcentral/fileexchange/71320-boost-converter-pi-control-demo
2. https://www.mathworks.com/help/physmod/sps/ug/boost-converter-voltage-control.html
Hi, In the attache model, I slightly modified the model to monitor the inductor current and to more easily manually switch from constant reference voltage to a step reference voltage. The "delay" you are experiencing is normal. This boost converter has a pretty large output capacitor that needs to be charged up to the input voltage through the diode. During this initial transient switching is ineffective and you can clearly see a very large inductor current spike. This phenomenon is called "inrush current" and, for the boost converter, it prevents the output voltage from being controllable until the output capacitor has a voltage Vc greater than the input voltage Vin. In practice, you have tried to change the output voltage through a step reference voltage while the boost converter is still uncontrollable. As a recommendation, you should set the lower limit of the output of the PI controller (that is the minimum duty cycle) to 0.1-0.15 as a rule of thumb. Set the upper limit to 0.85-0.9 to keep the operation far from the low-efficiency region. It is not recommended to operate the boost converter with full 0-1 duty cycle. Hope this helps, Antonino
