AC Sources / Loads

Programmable AC power supplies, electronic AC loads, and bidirectional AC systems are essential components for testing and simulating grid-connected and AC-powered equipment. An AC power supply generates controlled voltage, frequency, phase angle, and waveforms, while an electronic AC load absorbs power and simulates defined electrical consumers. Bidirectional AC systems combine both functions and enable controlled energy flow in both directions, including regenerative operation.

The ET System portfolio includes linear AC sources, programmable grid simulators, conventional and regenerative AC loads, bidirectional AC/DC systems, and high-bandwidth four-quadrant power amplifiers. Available solutions cover single-phase, split-phase, and three-phase applications ranging from compact laboratory instruments to scalable high-power test systems.

Select the appropriate product category according to the required energy direction: programmable AC power supplies and grid simulators supply a device under test (DUT), electronic AC loads absorb power, and bidirectional AC sources and loads support energy flow in both directions. Typical applications include testing power supplies, inverters, UPS systems, onboard chargers, drives, generators, energy storage systems, and other grid-connected equipment.

How to Choose the Right AC Source or Load

The most important selection criterion is the required direction of energy flow between the test system and the device under test (DUT). Once the appropriate product category has been identified, the phase configuration, voltage, current, power, frequency range, dynamic behavior, grid-simulation functions, automation interfaces, and mechanical integration should be evaluated.

• Supplying a DUT: Choose a programmable AC power supply or grid simulator when the test system must generate controlled voltage, frequency, phase angle, or grid conditions. Typical applications include testing power supplies, household appliances, industrial electronics, avionics equipment, motors, and grid-connected devices.
• Loading a DUT: Choose an electronic AC load when the DUT generates electrical energy and a defined consumer must be simulated. Typical applications include testing AC sources, generators, UPS systems, inverters, and protection functions.
• Energy flow in both directions: Choose a bidirectional AC source and load when the DUT must both receive and return energy. Typical applications include inverter, onboard-charger, drive, energy-storage, and regenerative power-electronics testing.
• Phase configuration: Determine whether the DUT requires single-phase, split-phase, or three-phase operation. For three-phase applications, check whether each phase must be controlled independently and whether balanced and unbalanced conditions are required.
• Voltage, current, and power: Define the required RMS voltage, peak voltage, current, active power in kW, apparent power in kVA, and short-term overload capability. Clarify whether three-phase voltage values are specified phase-to-neutral (L-N) or phase-to-phase (L-L).
• Frequency range and bandwidth: Define the required fundamental frequency and higher-frequency signal components. Standard grid testing may only require frequencies around 50 or 60 Hz, while avionics, dynamic testing, or power amplification may require frequencies and bandwidths up to several kilohertz.
• Grid and waveform simulation: Check whether programmable voltage and frequency sequences, phase-angle changes, voltage dips, interruptions, ramps, phase imbalance, harmonics, and arbitrary waveforms are required. Also verify the availability of applicable IEC, EN, grid-code, or application-specific test functions.
• Load behavior: For AC load simulation, define the required operating modes, power-factor range, crest factor, active and reactive power, and whether resistive, inductive, capacitive, or nonlinear load characteristics must be reproduced.
• Dynamic performance: Consider voltage and current slew rates, response time, settling time, overshoot, minimum event duration, load-step behavior, and transitions between source and load operation.
• Accuracy and power quality: Check programming and measurement accuracy for voltage, current, power, frequency, phase angle, and power factor as well as resolution, total harmonic distortion (THD), ripple, noise, and data acquisition rate.
• 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 mains voltage, phase configuration, input current, connection type, and facility requirements. Regenerative systems can return absorbed energy to the mains and reduce heat generation compared with conventional dissipative loads.
• Mechanical integration and safety: Consider benchtop or 19-inch rack installation, dimensions, weight, cooling, AC and DC connections, emergency shutdown, interlocks, grounding, isolation, and protection against accidental contact.
• Parallel operation and scalability: For higher current or power requirements, verify whether the selected series supports parallel or master-slave operation and which operating limits apply to the combined system.

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