What are power modules?
High-performance power modules are the core of Danfoss inverters. They integrate all power semiconductors into 8 cm long components. The modules consist of semiconductors (transistors and diodes) placed as required on a highly heat conductive material, covered with a see-through silicon paste. This provides a very stable thermal environment and is easily mounted on a heat sink or similar. Depending on the type and size of the inverter 1- 4 power modules are required. Power modules are used for DC to DC and DC to AC conversion.
Why use power modules?
The compact nature of the power modules enable more components in less space, while the heat dissipation capabilities ensure that cooling of the components is easier. Mounted on the heat sink of the inverter the power modules have ideal conditions for keeping the temperature down. Internal temperature sensors are placed near the power modules, ensuring that forced cooling is applied once the temperature rises to a set level. The cooling is only applied when necessary and as the modules have so good dissipation abilities, only little energy is used, increasing overall performance of the inverter. The reason for being so observant of temperature is due to the fact that by any temperature increase above normal operating temperature for a component, the life and/or performance of the component is decreased.
Another reason for using power modules rather than placing the discrete components directly on the printed circuit board is found in the topology of the inverter. The TripleLynx inverter for instance, has a complex three level topology requiring a lot of inter connections. If a traditional mounting of the components was used the relatively long distances between them would result in problems with stray inductance. Using power modules these problems are eliminated.
Power modules additionally play a part in ensuring production quality and thereby product quality. This is due to the fact that the more components in a product the more soldering and connecting points are required. Using power modules the one large component replaces more than a dozen others, thus eliminating several potential sources of bad connections.
Making better inverters
By using power modules the components that play an essential part in precise and correct conversion of energy are safely stored in an environment, which provides the best working conditions. They additionally enable the use of complex topologies, which in turn grant better inverters.