POWER ELECTRONICS A brief history of power electronics and why it's important

| Author / Editor: Luke James / Johanna Erbacher

Although power engineering and electronics may not be seen by many as “exciting” as other forms of engineering, the field plays a hugely important role that has wide reaching applications, and this cannot be understated.

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A mercury rectifier on display in Switzerland before being decommissioned.
A mercury rectifier on display in Switzerland before being decommissioned.
(Source: Timberwind)

Power electronics plays an essential part of virtually every device and system in one or more ways. Any device that requires an input of electrical power is driven by power electronics which convert electrical energy of one type into another type, such as AC to DC.

However, this is just the narrow technical explanation; the real-world impact of power electronics is much wider. And as the world continues to suffer at the hands of COVID-19, we are seeing more and more examples of just how important power electronics and all those who work in the field are.

A brief history of power electronics

Power electronics has a rich and extensive history. It first emerged at the turn of the 20th century with the introduction of Peter Cooper Hewit’s mercury arc valve, a type of rectifier that converts high voltage alternating current (AC) to direct current (DC). These were used in applications such as electric railways, industrial motors, streetcars, high-voltage direct current power transmission, and radio transmitters.

A few years later in 1096, Lee De Forest’s triode was introduced. In 1925, Errol Shand’s metal tank rectifier came along, then Joseph Slepian’s ignitron in the 1930s.

In fact, all early innovations up until the late 1940s applied to energy control. It wasn’t until 1948 when things truly took off, with the invention of the silicon transistor at Bell Laboratories. Another device that emerged around this time was the thyristor, a name for any semiconductor switch where the bistable operation depends on p-n-p-n regenerative feedback. The most widely known example of a thyristor is the silicon-controlled rectifier (SCR), introduced in 1954 by Bell Laboratories.

By this point, several power semiconductor devices had been introduced, including the bipolar junction transistor (BJT) and the metal-oxide-field effect transistor (MOSFET).

Why does all this matter?

Power electronics is responsible for the conversion and control of electric power, with converters modifying the primary characteristics of electrical power such as voltage, current, frequency, and the basic form of AC or DC. This level of control enables the setting and regulation of nonelectrical parameters, such as how fast a motor goes, how far a radio transmits, or how hot an oven gets.

As such, power electronics systems and technologies are used in a huge range of applications, from mobile phones to electric vehicles (EVs) and kitchen appliances to lighting. Any system or application backed by electricity that you can think of will have power electronics at its core, enabling its function. As such, it’s an area that is highly influential in our digital world and modern lives.

Some other applications of power electronics include:

  • Temperature and lighting control;
  • Solar power and renewable energy;
  • Medical applications;
  • Computer networks and data centers;
  • Military;
  • Electric power networks; and
  • Transportation.

And as the demand for energy grows, we as a race will rely more and more on the ability to manipulate energy sources to maintain and improve our modern and comfortable standard of living. Power electronics will also play a crucial role in battling the climate crisis and helping nations achieve their carbon neutrality and carbon zero goals.

Also important are semiconductors, power electronics innovations which enable many of the applications we take for granted today. MOSFETs, for example, are used for a huge number of purposes including switching power supplies, power converters, motor control, and voltage regulators. Another type of semiconductor, the bipolar junction transistor, is used in timers, delay circuits, and amplifiers.

In short, power electronics provides us with the ability to control large amounts of energy with increasing efficiency and ingenuity. Without this, it’s hard to imagine what our world would look like today.