Generator

Generator

The Generator represents the performance of a generic 3-phase generator. The generator is intended to run with an efficiency map subelement, plugged into its S_map socket.

Usage

• The input design parameters that must be specified by the modeler when creating an instance of this Generator component are mass specific power (SpecificPower), design efficiency (effDes), frequency, and voltage (Vbus_LL). This component will produce electrical power at the specified voltage and frequency, equal to the mechanical power at its shaft port. times its operating efficiency.

• When running ONDESIGN, this component will determine its design speed and design torque by saving off the values at the shaft port. The operating efficiency will be the effDes. when running OFFDESIGN, the model will call its S_map subelement (if it exists), to look up the efficiency at the current operating point. It will then run with that efficiency.

• This component, being a source component, must have its electricPowerType specified, and will propagate this power type information to components downstream of it when findSourcesAndPropagate() is called. Further, being a generator, it is expected that the output power type is 3-phase AC, so this is the default value. Typically, this value does not need to be set manually. For more information, see ElectricPort.prt.

• This component transforms power, from mechanical power at its shaft port, to electrical output power. Because this component represents a transformation of power, it includes a node. Being a component including a node, a voltage must be specified at this component. However, being a source component, its voltage is typically set to a fixed value (unless the modeler changes it to be otherwise), and it does not need solver variables to operate.

• 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.

• The " + isA() + " component does not use solver variables, however it includes sizing logic. this logic calculates mass as well as calculates the design torque and speed values. These values are used by a performance map (if one is plugged into the S_map socket) to calculate efficiency at the current operating point. For more information about performance maps for this component, see MotorGeneratorMap.int