What Is an AC Power Supply?
AC power stands for alternating current power. It refers to power that changes direction and magnitude with frequency. Distributed network power, the lines that supply industries, commercial ventures, and homes all use AC power.
All electric power supplied by power companies to ordinary households is AC power. Air conditioners, refrigerators, lighting fixtures, and other home appliances that are plugged into electrical outlets all run on AC power. It’s the same with industrial premises: motorized pumps, large-scale refrigeration units, and even the control systems that manage all of these larger electrical machines, all supply AC power. Sometimes that power is supplied as a single-phase line, sometimes as a three- or four-phase line power supply, but it still travels as a frequency-regulated alternating current AC power supply.
In industrial applications, devices that convert direct current (DC) to alternating current are also called AC power supply and are widely used. Inverters may be required for these to run correctly.
Uses of AC Power Supplies
AC power supplies are used in a wide range of applications, from general home appliances to industrial equipment.
Many household appliances, such as hair dryers, air conditioners, and microwave ovens run on AC power. Kitchen appliances, multimedia devices, and wall sockets, all operate on AC power. Most industrial equipment, such as commercial refrigeration units, ventilation blowers for exhaust air, and industrial water pumps, are also powered by AC.
In the IT industry when referring to an AC power supply, the term uninterruptible power supply (UPS) is sometimes used. Uninterruptible power supplies are used to protect critical data servers and data storage. AUPS is a product that supplies AC power while charging the battery with commercial power during normal times, and supplies power from the battery when the commercial power goes out. An inverter is added to a UPS to ensure the batteries inside the unit are charged with DC power.
UPS is also used to supply uninterrupted AC power to precision equipment. Data servers are one example of such critical and precise equipment. Even the slightest disturbance of the AC power supplies can cause them to malfunction, making UPS essential.
Simulators are also available to test whether electrical equipment can be damaged by intentionally creating disturbances in the AC power supply.
Principles of AC Power Supplies
Commercial AC power is mainly supplied by synchronous generators. Synchronous generators use electromagnetic induction to supply power.
Electromagnetic induction is the principle that voltage is generated when a magnet is placed close to or away from a conducting solenoid (such as a wound copper wire). Synchronous generators create electric power by the voltage generated from rotating the windings at high speed while generating a strong magnetic field inside. A mechanically induced source of kinetic energy supplies rotor-generated force. As that force acts on a rotor, the generator stator receives magnetically induced power. The speed of the generator decides the initial frequency of the AC power.
AC (regulated) power supplies in the IT industry can be broadly classified into two types: AC stabilizer type (AVR) and frequency converter type (CV/CF).
1. AC Stabilizer Type
The AC stabilizer type stabilizes the output voltage and waveform, while the frequency converter type also stabilizes the frequency.
AC stabilizer systems are broadly classified into SLIDAC systems and tap-switching systems. The SLIDAC method uses a servomotor (servo motor) or a similar device to continuously switch the taps of a transformer to maintain constant AC voltage.
The tap-switching method compares the voltage of the input AC current with a reference voltage, corrects the error, and outputs the result.
2. Frequency Converter Type
Frequency converter systems are broadly classified into linear amplifier systems and inverter systems. In both methods, the AC current is converted to a DC current.
The output voltage and frequency are then corrected using a linear amplifier (linear amplifier method) and a DC/AC inverter (inverter method) and put out as AC power supplies.
Advantages of AC Power Supplies
There are two major advantages of AC power supplies as follows.
1. Easily Transformable
AC power supplies can be easily transformed according to the winding ratio of the transformer. Long-distance power transmission can be done at high voltage to reduce losses, and power can be easily extracted by placing a transformer at the demand location.
Although it is possible to convert voltage using a DC power supply, the cost of the converter itself and the time required for the conversion are high. The greatest advantage of AC power supplies is that this method of adjusting voltage can reduce the equipment cost of power transmission and distribution.
2. Easy Circuit Breakdown
AC power is characterized by cyclically alternating a positive and negative voltage. If you want to stop the current temporarily in the event of an accident or disaster, you can use the moment of zero current to interrupt the circuit, thereby minimizing damage to the electrical system and the circuit breaker itself.
Other Information on AC Power Supplies
Invention of AC Power Supplies
AC power supplies were invented by an inventor named Nikola Tesla. Tesla was born in what is now the Republic of Croatia and excelled in mathematics from an early age.
While a student at the Technical University of Graz, he saw a “gram generator” (a device for generating a direct current that functions as both a generator and a motor), which inspired him to think about ways to improve power generation. Five years later, he succeeded in inventing the world’s first AC current generator, the two-phase AC motor.
Tesla then developed his ideas on alternating current and went on to work for Thomas Edison, who was famous for inventing direct current. However, Edison was against Tesla’s invention of the AC current.
Both Edison and Tesla appealed to the usefulness and safety of the current they had invented, and a “DC current Edison vs. AC current Tesla” configuration was later created. After this confrontation, Tesla’s alternating current was recognized by the public, and today alternating current is indispensable.