DC_DC_Converter

DC-DC Converter

The DC_DC_Converter represents the performance of a generic DC-to-DC converter. This component is intended to run with an InverterRectifierMap subelement plugged into its S_map socket that represents its losses.

Usage

• The input design parameters that must be specified by the modeler when creating an instance of this DC_DC_Converter component are mass specific power (SpecificPower) and design efficiency (eff). This component will transfer power from input to output, with losses according to its design efficiency. Output voltage is related to input voltage by a ratio, K, which represents the combined effect of the turns ratio of an integrated transformer (if it exists) as well as the duty cycle. ONDESIGN, it calculates its mass (Mass) by dividing its ONDESIGN input power by its specific power.

• This component transforms power, from electrical power at its input port, to useful output (load) power. Because this component represents a transformation of power, it includes a node. Being a component including a node, its voltage is an indepedent variable. It also features a dependent that ensures that the electrical power at the input port, is sufficient to produce the output power demanded, plus the losses in this component (EP_I.S.r * eff == Pdemand).

• This component also has logic that represents control functions. These are enabled by adding the independent, ind_control, which will vary the Vo/Vi voltage ratio, K. This independent is intended to be a 'control knob' must be matched to a dependent somewhere else in the system (in the case of a hybrid power system with two sources, the dependent could represent a constraint on power split, or could represent the designation of one source or another as a constant power vs a constant voltage 'slack' bus).

• As a component that contains a node and has its voltage known at the beginning of the solverSequence[], it uses its prePass() method to call the electrical port update function to pass this voltage information to electrical components that it is connected to. Note that in the current implementation of the NPSS Power System Library, these components containing nodes do not know what currents are going through their ports at the beginning of an iteration. Because of this, they must be connected to power transmission components (cables and breakers), and these transmission components must be run before node-bearing transformation components like this one, as the transmission components will calculate and populate these current values. Note that this design is intended to be analogous to a common approach taken in fluid networks within NPSS rocket models.

• This component, like other power system components in the NPSS Power System Library, can optionally include thermal models. An optional thermal model is enabled by setting switchThermPort to TRUE, and plugging an EThermalMass subelement into the S_eThermMass socket. Doing these will add a temperature state (existing within EThermalMass) and a thermal port to the model. The thermal port is intended to connect this component to a second component that represents the mechanism by which heat is extracted from this component. This second component could represent a heat exchanger, cold plate, or just model heat transfer from the first component to the surrounding environment. For more information see EThermalMass.