AC Power Supplies

Programmable AC power supplies generate precisely controlled AC voltage, frequency, phase angle, and waveforms for powering electrical devices and simulating different grid conditions. They enable stable and reproducible testing of electrical and electronic systems in development, laboratory, production, and automated test equipment (ATE). Depending on the series, AC sources may also provide DC output, operate as a grid simulator, or absorb and regenerate energy.

The ET System portfolio includes linear AC power supplies, single-phase AC sources, flexible single- and three-phase systems, programmable grid simulators, and bidirectional AC sources and loads. Available solutions range from compact laboratory instruments to scalable high-power systems and dynamic AC/DC amplifiers.

Typical applications include testing power supplies, onboard chargers, inverters, UPS systems, drives, household appliances, avionics equipment, and industrial electronics. AC sources are also used to simulate voltage dips, interruptions, frequency deviations, phase imbalance, and other grid disturbances. The appropriate AC power supply is selected according to phase configuration, voltage, current, apparent power, frequency range, dynamic response, regenerative capability, interfaces, and mechanical integration. For separate load simulation, explore our programmable electronic AC loads.

How to Select an AC Power Supply

Selecting a suitable AC power supply starts with the electrical requirements of the device under test (DUT) and the grid conditions that must be simulated. In addition to voltage, current, and apparent power, the required phase configuration, frequency range, waveform quality, dynamic behavior, regenerative capability, automation interfaces, mains connection, and mechanical integration should be considered.

• Phase configuration: Determine whether the DUT requires a single-phase, split-phase, or three-phase supply. Some flexible single- and three-phase AC sources allow the phase configuration to be changed by software. For three-phase systems, check whether independent phase adjustment and unbalanced operation are required.
• Output voltage: Define the required voltage range and clarify whether values are specified phase-to-neutral (L-N) or phase-to-phase (L-L). Also consider DC output, AC+DC operation, voltage resolution, and any required short-term overvoltage.
• Current, power, and inrush capability: Check the required RMS current, peak current, apparent power in kVA, active power in kW, and crest factor. DUTs with capacitive inputs, motors, transformers, or power supplies may require considerably higher inrush current than their nominal operating current.
• Frequency range and bandwidth: Define the required fundamental frequency and any higher-frequency components. Standard grid simulation may only require frequencies around 50 or 60 Hz, while avionics, dynamic testing, or amplifier applications may require frequencies up to several kilohertz.
• Linear or switched technology: Linear AC power supplies may be preferred for applications requiring low distortion, low noise, and precise waveform reproduction. Switched systems generally provide higher power density and are suitable for a wide range of industrial and high-power applications.
• Grid simulation and waveform generation: For grid and compliance testing, verify support for programmable voltage and frequency sequences, phase-angle changes, voltage dips, interruptions, ramps, phase imbalance, harmonics, and arbitrary waveforms. Also check whether the required IEC, EN, or application-specific test functions are available.
• Dynamic response: Consider voltage and current slew rates, response time, settling time, overshoot, switching between operating modes, and minimum event duration. High-speed applications may require an AC/DC power amplifier with greater bandwidth and fast response.
• Source, load, or regenerative operation: If the DUT can return energy, for example an inverter, onboard charger, drive, or energy storage system, a bidirectional AC source and load may be required. Regenerative systems can return absorbed energy to the mains instead of converting it entirely into heat.
• Accuracy and power quality: Check voltage, current, power, frequency, and phase measurement accuracy as well as resolution, total harmonic distortion (THD), ripple, noise, and data acquisition rate. The required values depend on whether the system is used for general power testing, standards testing, or precise research applications.
• Interfaces and automation: For automated test equipment (ATE), verify remote-control commands, sequence functions, trigger options, software compatibility, and available interfaces such as LAN, CAN, RS232, RS485, USB, SCPI, analog control, and digital I/O.
• Mains connection and regeneration: Check the available input voltage, phase configuration, input current, connection type, and facility limits for regenerated power. High-power systems may require fixed wiring, dedicated protection devices, and coordination with the electrical installation.
• Mechanical integration and cooling: Consider benchtop or 19-inch rack installation, dimensions, weight, airflow, cooling requirements, output connections, emergency shutdown, interlocks, and protection against accidental contact.
• Parallel operation and scalability: For higher power requirements, verify whether the selected series supports parallel or master-slave operation and which limits apply to the combined system.

For application-specific test benches, ET System can combine AC power supplies, electronic AC loads, DC equipment, measurement technology, safety components, power distribution, and control systems through test system integration. For support with selecting a suitable AC source or grid simulator, contact our technical sales team.