Power Electronics in Practice
The field of power electronics is relatively new as a distinct discipline, even though the applications and fundamental methods of a long history. As a special electrical engineering practice, it dates from about the time the SCR was introduced. The term was coined about 1970 to describe the subject as a cohesive discipline. Engineers active in power electronics are typically involved in one of six areas:
- Power supplies, either in general, or for specific power needs in computers, electronics instruments, telecommunications, portable equipment, or other electronic circuits.
- Power semiconductor devices.
- Electronic motor drives.
- Support of energy conversion and control in large power systems. This includes control of power networks, high-voltage DC systems, superconducting magnetic energy storage, alternative energy conversion, and controllers for generators.
- Electric transportation and mobile power, including electric cars, railways, aircraft electric power systems, and spacecraft power systems.
Examples of industries which need experts in power electronics include:
- Computer industry: need for lots of power at a variety of low DC voltages. Backup power is also important. The trend to voltage levels below 5 V will require considerable innovation.
- Telecommunications industry: needs power for transmission, signal processing, and auxiliary services. Highly reliable power sources must be distributed throughout large systems. Rapid communication system growth in developing countries offers vast opportunity. There is extraordinary need for portable communications technology as cell phones and other personal electronic devices grow in popularity and use.
- Aerospace industry: lightweight converters for aircraft energy needs and for spacecraft electric power processing. Reliability requirements are extreme. Conversion from solar power and other alternative energy sources. The all-electric aircraft is a recent development driven partly by advances in power electronics.
- Electric equipment industry: Power supplies for instruments, consumer electronics, portable and remote measurement devices, and many other products. Many of these represent major growth areas in power electronics. For example, power electronic ballasts for high-efficiency fluorescent lighting or high-power LED lighting are now being manufactured in high volumes.
- Industrial controls industry: motor and motion control applications. Power sensing and measurement. Advanced power-electronic AC motor controls are now readily available commercially. Such systems have replaced almost all existing DC motor systems, a trend which can be expected to continue over the next decades.
- Automobile industry: electric actuators and energy control. Electric traction systems. A typical passenger car contains dozens of electric motors – each controlled with power electronics. Air pollution, conventional fuel source scarcity, and recent advances in IGBTs and battery technology are opening up a revolution in electric cars.
- Electric power industry: emergency backup power supplies. Alternative energy source conversion. HVDC transmission. Power supply quality, and direct electronic control of utility grids. It is possible to move more energy through existing connections if power electronic controls are added. Devices suitable for the power grid are opening up new possibilities for so-called ‘smart-grids’.
These examples span nearly the full range of both light and heavy industry. Power electronics today influences the design of everything from office equipment and home appliances to high-speed transportation and satellites.