Thermal simulation

Thermal management is an important aspect of power electronic systems and is becoming more critical with increasing demands for compact packaging and higher power density. PLECS enables the user to include the thermal design with the electrical design at an early stage in order to provide a cooling solution suitable for each particular application.

Switching and conduction losses

Instead of determining semiconductor switching losses from current and voltage transients, PLECS records the operating condition of the semiconductor (forward current, blocking voltage, junction temperature) before and after each switch operation. It then uses these parameters to read the resulting dissipated energy from a 3D look-up table. During the on-state, the dissipated power is computed from the device current and temperature.

This combination of ideal switch models with detailed loss data provides an efficient and accurate alternative to detailed device simulations. The required data tables are entered via the visual editor integrated into PLECS.

Heat sink concept

The core component of the thermal library is an idealized heat sink depicted as a semitransparent box. A heat sink absorbs the thermal losses dissipated by the components within its boundaries. At the same time, a heat sink defines an isotherm environment and propagates its temperature to the components which it encloses.

Thermal equivalent network

Heat conduction from one heat sink to another or to an ambient temperature is modeled with lumped thermal resistances and capacitances that are connected to the heat sinks. This approach allows you to control the level of detail of the thermal structural model.