DCDCControl

Use

This component controls the duty cycle (DRef) of a DC/DC-converter dependent on the reference power ▶PRef.

Recommendation: A fully coupled model for the conversion from battery dc to an ac connection is already available as Batt2ACInverter. Use this model or take this model as example reference to create an own version.

Parameters and Connectors

To use the DCDCControl, several connectors from different sources must be connected. These are the values from the dc/dc converter the current of the dc input ▶IDCin, the voltage of the dc output ▶VDCout and the voltage of the input ▶VDCin. The other parameters required are taken from a battery or another electrical generator and are the open-circuit voltage of the input source ▶VDCinOC, the minimum and maximum input voltage ▶VDCinMin and ▶VDCinMax. The final parameter passed to the component from outside is the reference power ▶PRef, which regulates the conversion.

The DCDCControl component uses an internal PI controller to control the reference duty cycle DRef and further DRef has a defined time delay behavior (see time delays). To set the behaviour, the parameters of the PI controller, the time constant tPI and the gain constant kPI, must be specified. In addition, the maximum power of the dc/dc converter PMax has to be set.

Model Background

Time Delays

The times of the DCDCControl are modeled in the component via PT1 elements, whereby the entered parameters (e.g. tPI) represent the time constant of the PT1 element. When the DCDCControl's power is changed, the reference duty cycle DRef decreases according to the typical behavior of the step response of a PT1 element. This means that after once the time constant (e.g. tPI= 5s) the reference duty cycle drops to 37% of its original value, after twice the time constant (2 * tPI) to a value of 5% and after five times the time constant (5 * tPI) to 0.8%.