When you need a robust solution for high-power switching, power modules are often your best bet. Power modules are high-power electrical components that contain a single or several components combined into a functional, isolated unit. They typically have a base plate for mounting a heat sink and electrical contacts that allow for quick and easy mounting and removal. By manufacturing the component as a module, improved power handling, reliability, and decreased parasitic circuit elements are all possible.
Common power modules include transistors and diodes. Metal oxide semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), and silicon controlled rectifiers (SCRs) are some of the most common switching elements found as power modules. Some power modules combine transistors into commonly used configurations, including both half-bridge and H-bridge configurations. These configurations allow the user to easily switch the direction of current through a motor from a single voltage power supply. More complex modules that include up to six transistors are also available for inverting applications—switching direct current electricity into alternating current—commonly found in renewable or “green” energy systems.
Diode power modules are also available and come in single, dual, or other configurations. Bridge rectifiers are a common use of diodes for converting alternating current into direct current electricity. Four diodes can be used as a bridge rectifier for single-phase alternating current, while six diodes can be used to rectify three-phase current. Both single-phase and three-phase bridge rectifiers are conveniently available in power modules for ease of use and replacement.
Like other technologies, power modules have continued to evolve to better meet engineering challenges and simplify their use. Intelligent power modules are some of the most recent developments in power module technology. These modules typically contain an IGBT with added control and protection circuitry. Control circuitry provides the driving circuitry for switching the IGBT and gate drive logic to allow simple turn on and turn off. Intelligent power module protection circuitry can prevent problems from high temperatures, excessive current, short circuits, and undervoltage conditions.
The electrical components included in power modules are typically potted in plastic with a metal base plate that allows for adequate cooling when needed under high-power situations. Historically, power modules used screw contacts. More recently, pins and press-fit contacts have also become available. The electrical contacts on power modules allow for high current and high voltage use without soldering. This simplifies installation, removal, and replacement.
Applications of power modules are common in electric cars and other electric motor controllers, appliances, power supplies, electroplating machinery, medical equipment, battery chargers, AC to DC inverters and converters, power switches, and welding equipment. Most high-power switching applications can be implemented with power modules to gain the advantages that they can provide.
WeberAuto at Weber State University Davis has provided a YouTube video of all the electronic components in a Tesla vehicle:
In summary, power modules provide several advantages over isolated components, including:
- Improved power handling and reliability
- Simple heat sinking through the integrated base plate
- Ease of installation, removal, and replacement
- Simplified circuit implementation, especially with intelligent power modules