DC Power Supply for Energy Storage Testing: BESS, PCS and Grid Converters

Energy storage validation lives at the intersection of high power, bidirectional flow and grid-code compliance. This guide helps test engineers and buyers spec a regenerative DC source for BESS, power conversion systems and grid-tie converters without over- or under-buying.

The energy-storage test problem in one paragraph

A battery energy storage system (BESS) and its power conversion system (PCS) must charge from the grid and discharge back to it on command. To test the PCS or grid converter on the bench, you need a DC source that emulates the battery, sinking energy during charge and sourcing it during discharge, while the converter exercises its grid-side controls. A bidirectional, regenerative DC power supply is the natural fit, and recovering discharge energy at up to 93% efficiency keeps long compliance campaigns affordable.

The N35500 platform from Ultra Power Systems provides four-quadrant operation with CC/CV/CP/CR modes and optional battery emulation, so the converter under test sees a realistic DC bus rather than a stiff rail.

Grid-code and standards alignment

PCS and grid-tie converter testing is governed by interconnection standards. Specifying a source whose ecosystem already references these requirements shortens your path to credible reports:

IEEE 1547 for interconnection and interoperability of distributed resources.
IEC 61010 for measurement and control equipment safety.
ISO 17025 laboratory competence for accredited results.

The platform carries CE, IEC 61010, IEEE 1547 and ISO 17025 references, supporting BESS and PCS validation programs end to end.

Sizing for BESS DC-bus voltage and power

Spec voltage from the storage system's DC-bus window and power from the converter's rated throughput. The 0–2250 V range covers low-voltage commercial racks through 1500 V utility-scale strings.

Storage class	Typical DC bus	Supply voltage class
Residential / C&I module	48–600 V	0–1000 V
Containerised C&I BESS	600–1000 V	0–1500 V
Utility-scale string	1000–1500 V	0–2250 V

A single unit delivers up to 42 kW in 3U, and master/master parallel scales to megawatt grid-converter benches. Battery emulation (NS81000, 7 libraries plus custom curves) lets the PCS see a realistic state-of-charge profile during testing.

Bidirectional cycling, comms and automation

Seamless source-to-sink transitions with ≤5 ms response let the converter ride through charge/discharge reversals the way it will in the field. With 0.02% F.S. accuracy your round-trip efficiency and capacity figures stay defensible. LAN, RS232, RS485 and CAN with SCPI, Modbus-RTU and CANopen integrate the supply into automated grid-code test sequences, so anti-islanding, ramp-rate and ride-through routines can run unattended overnight.

Because the same hardware sources and sinks, you avoid the cost and floor space of a separate electronic load, and the regenerated discharge energy offsets the draw of the rest of the bench. For multi-string or containerised BESS programs, several units can run in parallel or as independent channels so you validate more devices per shift. When your DC-bus window, power and channel count are defined, scope a BESS or PCS test system with us, request a quote or email Ultra Power Systems.

Frequently asked questions

Why use a regenerative supply for energy storage testing?

Storage testing cycles large amounts of energy in both directions. A regenerative bidirectional supply returns discharge energy to the grid at up to 93% efficiency instead of dumping it as heat, cutting electricity and cooling costs and removing the need for a separate electronic load.

Does the supply support IEEE 1547 PCS testing?

Yes. The platform references IEEE 1547 alongside IEC 61010 and ISO 17025, and its bidirectional four-quadrant operation lets you emulate the battery while the PCS or grid converter exercises its interconnection controls.

Can it emulate a real battery DC bus?

With the NS81000 battery-emulation option you get 7 built-in chemistry libraries plus custom curves, so the converter under test sees a realistic state-of-charge ramp rather than a flat voltage rail.

How do I scale to megawatt-class grid-converter testing?

Use master/master paralleling of the same N35500 hardware. The architecture scales from a 42 kW 3U unit into the megawatt range while keeping one control and software interface.

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