A Practical Guide to AC Power Sources: What They Are and How They Work

Key Characteristics of AC Power

AC power, short for alternating current, is a widely used form of electricity that flows by periodically reversing direction and changing magnitude. It typically appears as a sinusoidal waveform and is the default electrical format for most residential and commercial environments.

Purpose and Role of an AC Power Source

An AC power source (also known as an AC power supply) is a device that delivers stable alternating current to other equipment. It is particularly crucial for sensitive or precision devices that cannot tolerate voltage fluctuations from standard grid power. These instruments require a consistent and controlled power input, which an AC source ensures by adjusting the voltage or frequency according to the device's needs.

The AC power supply converts standard AC grid input into the desired output format, providing a stable power condition across various countries and applications. It also supports testing environments by simulating scenarios such as voltage sags, surges, harmonics, and momentary shutdowns, which help verify the resilience and reliability of the Device Under Test (DUT).

To summarize, an AC power source must fulfill three core functions:

• Deliver stable voltage output
• Maintain steady waveform regardless of input fluctuation
• Support different types and variations of electrical loads

 

Common Categories of AC Power Supplies

Single-Phase AC Power Supply

A single-phase AC power supply routes current through one live wire and a neutral wire. It is commonly used in households and office applications where the power demands are relatively low. Many everyday appliances like fans and coolers operate effectively on single-phase systems due to their simple requirements and compatibility with non-polarized AC voltage.

Three-Phase AC Power Supply

A three-phase AC power source involves three conductors with a 120° phase difference. It offers a more efficient and cost-effective solution for high-power transmission. These power supplies are preferred in industrial environments to power motors, compressors, and heaters. Preen’s AFV+ series, for example, allows users to configure balanced or independent voltages for advanced applications, making it ideal for regions with varying power standards.

Typical Use Cases for AC Power Sources

AC power supplies find applications across a wide range of fields. Preen provides reliable and versatile AC power solutions, from single-phase to high-capacity three-phase systems, designed to meet diverse testing and application needs.

• Home and Laboratory: Ideal for household appliance testing, R&D experiments, and single-phase EV charging or performance evaluation.
• Industrial Applications: Powers high-demand equipment such as motors, compressors, and heaters, and supports PV inverter testing as well as three-phase EV charging systems.
• Energy and R&D Testing: Covers PV inverter evaluation, EV-related testing, and various laboratory applications.
• Renewable Energy and Compliance: Supplies power for motors, compressors, and renewable energy systems, while supporting regulatory tests such as Low Voltage Ride Through (LVRT).
• Production Line and Simulation: Used for renewable energy and EV inspections, IT/SMT production line verification, and simulation of various voltage and frequency conditions.

 

Preen’s AC Power Product Lineup

AC Power Source

Product Name	AFV-P Series High Performance Programmable AC Power Source	AFV+ Series High Power Programmable AC Power Source	AFV Series High Power Programmable AC Power Source	PAS/PFV Series Regenerative Grid Simulator	AFC Series AC Power Source / Frequency Converter	AMV/AMF Series 400Hz Power Supply / Ground Power Unit
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Features	Programmable AC power source with DC output and precision measurement.	An upgraded high power programmable AC power source of AFV series, with improving THD and Load Regulation.	High power programmable AC power source utilizing advanced PWM technology to deliver power.	Regenerative high power AC power source, built in with Low Voltage Ride Through Test (LVRT) test function.	AC power source which can simulate standard or abnormal voltage and frequency status.	Ground power unit which is compliant with MIL-STD-704F.
Output Power	600VA~5kVA	10kVA~2000kVA	10kVA~2000kVA	30kVA~2000kVA	10kVA~2000kVA	AMV: 30kVA~180kVA AMF: 500VA~400kVA
Output Voltage	0~310V	0~310V	0~310V	0～300V 0-350V(opt)	0~310V	115/200V ±10%
Output Frequency	A: 5~2000Hz B: 15~1000Hz	A: 45~500Hz B: 45~120Hz C: 300~840Hz	45~120Hz 45~500Hz (Opt.)	45~65Hz 40~70Hz (Opt.)	45~65Hz, 100Hz/120Hz/200Hz/240Hz/400Hz (Opt.)	AMV: 300~500Hz(Stand Alone) 400Hz(Fixed) AMF: 350~450Hz 400Hz (Fixed)
THD	≤ 0.3-2%	≦ 0.5%	≦ 1%	≦ 2%	≦ 2%	AMV: ≦ 2% AMF: ≦ 0.5-3%
Load Regulation	≦ 0.07% F.S.	≦ 0.5%	≦ 1%	≦ 1%	≦ 1%	AMV: ≦ 1% AMF: ≦ 0.5-1.5%
Efficiency	≧ 77%-80% at max. power	≧85%-90% at max. power	≧85%-90% at max. power	≧ 92% at Max. Power	≧85%-90% at max. power	AMV: ≧ 92% at Max. Power AMF: ≧ 87% at Max. Power
Operational Temperature	0-40℃	0℃-45℃	0℃-45℃	0℃-45℃	0℃-45℃	AMV: -40℃-55℃ AMF: -20℃-45℃
IP Level	-	-	-	-	-	AMV: IP54
Overload Capacity	-	-	-	-	-	AMV: 125%/600s, 150%/30s, 200%/10s, (Optional) 150%/60s, 200%/30s, 250%/10s, 300%/1s AMF: 120%/1 hr, 150%/60s, 200%/15s
Crest Factor	≧ 3	≧ 3	-	-	-	-
Inrush Current	≧ 4.5 times of max.output current (rms)	-	-	-	-	-
Response Time	≦ 300 μs	≦ 1ms	≦ 2ms	≦ 2ms	≦ 2ms	-
DC Output Voltage	0-210V / 0-420V	-	-	-	-	-
Input Power Factor	-	≧ 0.9 at Max. Power	≧0.9 at max. power ≧0.85% at max. power	≧ 0.99 at Max. Power	≧0.85 ≧0.9 at max. power	AMV: ≧94%at max. power AMF: ≧85% at max. power
Input Voltage	98-132VAC/196-264VAC	380VAC±15% 200VAC, 208VAC, 240VAC, 400VAC,	/380VAC±15% 208/220VAC,480VAC,(Optional)	380VAC±15%	-	-
Input Frequency	47~63Hz	47~63Hz	47~63Hz	47~63Hz	-	-
Remote Interface	Standard:　RS232,RS485, Ethernet, USB, PLC Remote In&Out Option: GPIB, Analog	Standard: RS232, RS485, Ethernet Option: Interface Card(RS232&RS485, Ethernet,USB) GPIB, Analog	Standard: RS232, RS485, Ethernet Option: Interface Card(RS232&RS485, Ethernet,USB),GPIB, Analog	Standard: RS232, RS485, Option: Ethernet, GPIB, USB	Standard: RS232, RS485	AMV: RS-485 AMF: RS-485 (opt.)
Weight	16～61.5kg (35.3～135.6lbs)	-	-	-	-	-
Certification	CE & RoHS	CE & RoHS	CE & RoHS	CE & RoHS	CE & RoHS	CE & RoHS
Application	EV, Home Appliance, Laboratory	PV Inverter, EV, Industrial Power Supply, Renewable Energy	PV Inverter, EV, Laboratory	PV Inverter, EV, Laboratory, Motor & Compressor	EV, Renewable Energy, IT/SMT Production Line
	More Details	More Details	More Details	More Details	More Details	More Details

 

FAQ About AC Power Supplies

How Does an AC Power Supply Work?

An AC power supply typically comprises a transformer, rectifier, and filter. The transformer adjusts the input voltage, the rectifier converts it into pulsating DC, and the filter smooths the output to provide usable power to the load.

What Is the Standard Operating Voltage for AC?

Standard AC operating voltages are typically 220V and 380V, depending on regional requirements.

What Is the Nature of an AC Power Source?

An AC power source is fundamentally a method of delivering energy from power generation stations to end-users. It is versatile and essential for both residential and commercial power distribution due to its ability to transform and travel efficiently.

What Types of AC Sources Exist?

What Is a Programmable AC Power Supply?

A programmable AC power source allows users to control voltage and frequency dynamically to simulate different power grid conditions. It can be operated remotely using digital interfaces like RS232, USB, GPIB, or analog inputs.

Which AC Power Source Is Suitable for EVSE Testing?

Preen’s AFV+ and PAS series can conduct various input and performance tests for EV chargers. The AFV+ series handles variable input simulations, while the PAS series is capable of power sourcing and sinking for regenerative testing.