Power Electronics - Applications

Applications

Power electronic systems are found in virtually every electronic device. For example:

• DC/DC converters are used in most mobile devices (mobile phones, PDA etc.) to maintain the voltage at a fixed value whatever the voltage level of the battery is. These converters are also used for electronic isolation and power factor correction.
• AC/DC converters (rectifiers) are used every time an electronic device is connected to the mains (computer, television etc.). These may simply change AC to DC or can also change the voltage level as part of their operation.
• AC/AC converters are used to change either the voltage level or the frequency (international power adapters, light dimmer). In power distribution networks AC/AC converters may be used to exchange power between utility frequency 50 Hz and 60 Hz power grids.
• DC/AC converters (inverters) are used primarily in UPS or renewable energy systems or emergency lighting systems. When mains power is available, it will charge the DC battery. If the mains fails, an inverter will be used to produce AC electricity at mains voltage from the DC battery.

Power electronics is the application of electronics for the control and conversion of electric power. Applications of power electronics range in size from a switched mode power supply in an AC adapter, battery chargers, fluorescent lamp ballasts, through variable frequency drives and DC motor drives used to operate pumps, fans, and manufacturing machinery, up to gigawatt-scale high voltage direct current power transmission systems used to interconnect electrical grids.

Motor drives are found in pumps, blowers, and mill drives for textile, paper, cement and other such facilities. Drives may be used for power conversion and for motion control. For AC motors, applications include variable-frequency drives, motor soft starters and excitation systems.

In hybrid electric vehicles (HEVs), power electronics are used in two formats: series hybrid and parallel hybrid. The difference between a series hybrid and a parallel hybrid is the location of the electric motor in comparison to the internal combustion engine (ICE). The power electronic devices used in electric vehicles consist mostly of dc/dc converters for battery charging, and dc/ac converters to power the propulsion motor. Electric trains are a big movement in public transportation, especially in rural areas. These trains use power electronic devices to obtain power, as well as for vector control using pulse width modulation (PWM) rectifiers. These devices are used, since the trains obtain their power from the lines they transport along. Another new usage for power electronics is in elevator systems. These systems may use thyristors, inverters, permanent magnet motors, or various hybrid systems that incorporate PWM systems and standard motors. The uses of power electronics discussed above are just some examples of the use of power electronics in residential and public applications.