How to Select the Correct Power Supply

What is a Power Supply?

A power supply, also commonly referred to as a power source, is a device that takes the electrical current from a separate source of electricity (such as wall outlets, batteries, or generators) and converts it into the necessary voltage and current values required to power a load. Power sources must be supplied with a controlled amount of current and an accurate voltage to provide connected devices with the proper amount of power. To support the wide array of applications that are required from power supplies, each source has access to a variety of capabilities to support their given application.

Key Attributes of Modern Power Supplies

As power supplies have evolved to suit a multitude of purposes, certain attributes have become particularly important to support those causes. Some of those attributes include:

Advanced Testing – To ensure a test goes correctly, the power source used must simulate whatever test is conducted with a high level of accuracy. To do this, the power supply must be both consistent and repeatable.
Compact Designs – The smaller the design, the smaller the footprint and greater power efficiency in relation to the power supply volume.
Precision Power – Applications where specific amounts of power are required, such as medical device testing, research, and high-energy weapons, prevent damage to the equipment while also ensuring there is no loss in performance.
Programmable Power and Modularity – Being able to program a power supply allows users to adjust voltage, current, and frequency as needed to meet the power requirements of a plethora of products and testing environments.
Slew Rate – Slew rate is the maximum rate of change of an output voltage or output current per unit of time. Power supplies need particular slew rates to prevent overshoot and stress in a DUT whenever changes in voltage or current occur outside of its expected ranges. This can be useful for situations such as replicating start-up conditions for engines that start in cold ambient conditions, lowering their immediate voltage output below typical ranges.

Industries Where Power Supplies are Used

Aerospace/Defense – Not only are power supplies useful for the simulating power conditions found in space, but they are also crucial for upkeeping electronics repairs in military depots.
Automotive and Transportation – All new vehicles require power supplies during their manufacturing process to perform a variety of tests. Additionally, automotive R&D labs use power sources for electronic integration and margin testing.
Commercial/Industrial – Commercial and industrial R&D labs require power supplies to perform margin and integration testing for electrical devices, electronics, and materials during the development cycle.
Energy/Power Generation – Programmable power supplies are required to adjust to ever-changing standards and testing solutions that come from renewable-energy, power-generation applications in addition to their current role of supporting conventional power-generation systems.

Purposes for Using Power Supplies

Power Emulation – Emulating power sources are important for ensuring a product can handle similar properties that the device under testing would experience in the field.
Process Power – Process power transforms a product by controlling where and how a power system is used. This is done to load down the device and stress the system to ensure it does not succumb to early electronic failure.
Stimulus Power – Typically done in power and test operations, stimulus applications are where the power supply sends a specific input to get the load to respond.

What are the Different Types of Power Supplies?

Power supplies can come in a variety of forms depending on the application being tackled. Below is a list of some of the most used power supplies and what they do.

AC to DC power supplies transform AC power, which is the type of energy typically used to power the world, into the precise DC voltage required by the device under testing.

Battery chargers are power sources that can either charge a specific type of battery, or multiple types of batteries, depending on the complexity of the unit.

DC to DC power supplies modify existing DC voltages to fulfill specific requirements desired by a DC system.

Frequency converters are power supplies that transform electrical power to accommodate different pieces of electrical equipment based on their required frequency, whether that is 25Hz, 50Hz, 60Hz, 100Hz, or 400Hz.

High voltage power supplies are designed for applications such as specific avionics systems and electrostatic equipment that require high levels of voltage that cannot be met by typical power supplies.

Linear power supplies send a regulated, continuously flowing voltage to their respective load, like a sink faucet continuously pouring water.

Regenerative power supplies can both supply and accept power, allowing them to perform applications such as energy storage, while cutting down on energy waste and increasing general efficiency.

Switching power supplies regulate voltage by quickly toggling the transistor on and off at high frequencies to enable precise voltage regulation with minimal power loss. This can be compared to flipping a light switch on and off repeatedly to save power as opposed to leaving it on continuously.

What Are the Common Test Standards Used with Power Supplies

As mentioned above, no singular power supply fits for all situations. This is commonly reflected in the wide array of test standards that are created to suit different industries and products. Some of these test standards include:

California Instruments Sequoia SQ0090 Regenerative AC Grid Simulator

Voltage:
- AC - Low Range: 0 - 166Vrms L-N, High Range: 0 - 333Vrms L-N
- DC - Low Range: 0 - 220VDC, High Range: 0 - 440VDC
Current (Per Ø):
- FSV – 1800.7/90.1Arms (AC), 91/68.2Adc (DC)
- Max – 250/125Arms (AC), 125.8/94.6Adc (DC)
Power: 90kVA/kW, 1/3Ø

Learn More About the Sequoia SQ0090

California Instruments Tahoe | TA0045A1 Power Supply

Voltage:
- AC - Low Range: 0 - 166Vrms L-N, High Range: 0 - 333Vrms L-N
- DC - Low Range: 0 - 220VDC, High Range: 0 - 440VDC
Current (Per Ø): 125/62.5Arms, 85/42.5ADC
Power: 45kVA/kW, 1/3Ø

Learn More About the Tahoe TA0045A1

Chroma 17040E | Regenerative Battery Pack Test System

Voltage: 100 – 1700V
Current (Per CH): 400A @ 1700Vrange, 800A @ 850Vrange
Power: 200kW

Learn More About the 17040E

ITECH IT79165-350-990 Regenerative Grid Simulator

Voltage: 350V
Current: 990A
Power: 165kVA

Learn More About the IT79165-350-990

Pacific Power 3550AZX Regenerative AC & DC Power Source

Voltage:
- AC – Low Range: 0 ~ 225Vac, High Range: 0 ~ 440Vac
- DC – Low Range: 0 ~ ±335Vdc, High Range: 0 ~ ±650Vdc
Current:
- 1Ø
  - Low Vrange: 390Arms (AC), 300Adc (DC)
  - High Vrange: 225Arms (AC), 150Adc (DC)
- Split
  - Low Vrange: 130Arms (AC), 100 (DC)
  - High Vrange: 75Arms (AC), 50 (DC)
- 3Ø
  - Low Vrange: 130Arms (AC), 100 (DC)
  - High Vrange: 75Arms (AC), 50 (DC)
- Power: 55kVA/kW, 3Ø

Learn More About the 3550AZX