Nidec ACBOX V4 brings SiC and grid-forming to utility BESS

The UniQube PCS and ACBOX V4 container illustrate the reduced footprint Nidec Conversion targets for utility-scale grid-forming storage deployments

(Image courtesy of Nidec)

Nidec Conversion unveiled two utility-scale energy platforms at Intersolar Europe 2026 in Munich as grid-forming capability becomes an increasingly expected feature of European storage procurement. ACBOX V4, the latest generation of the company’s integrated AC block battery energy storage architecture, replaces the IGBT-based power modules of earlier generations with a silicon carbide semiconductor approach and adds native grid-forming capability with synthetic inertia. Its companion launch, the UniQube power conversion system, arrives rated for long-duration storage applications and designed for system voltages beyond what current projects require. Both platforms are developed and assembled in Europe.

SiC-based distributed conversion and what changes in ACBOX V4

The defining architectural change in ACBOX V4 is the move to silicon carbide semiconductors within a distributed power conversion topology. Earlier ACBOX generations used IGBT-based 4-quadrant AC/DC power conversion. V4 adopts SiC across a distributed architecture, which Nidec Conversion says delivers improved efficiency and higher availability alongside finer granularity in energy management. The integrated design reduces system footprint for utility-scale deployments relative to the previous generation.

ACBOX V4 combines LFP batteries with this SiC-based distributed conversion, native grid-forming capability, advanced thermal management, and safety features within a single containerised unit. Nidec Conversion describes the platform as built with cybersecurity-by-design and a transparent supply chain in compliance with European standards, positioning that reflects the traceability and cybersecurity criteria now common in European project finance and grid operator procurement.

Grid-forming capability and the regulatory direction shaping BESS procurement

ACBOX V4’s native grid-forming implementation supports synthetic inertia and enables the system to operate as a voltage source rather than a grid-following load. The ACBOX product line has carried grid-forming with synthetic inertia and virtual admittance as a confirmed feature. V4 brings that capability into an architecture built around SiC-based distributed conversion.

The regulatory context adds commercial weight to the specification. In November 2025, ENTSO-E published its Phase II Technical Report on grid-forming requirements under the draft NC RfG 2.0 – a non-binding document providing technical guidance on grid-forming capability for non-synchronous generation and storage, intended as the basis for a future Implementation Guidance Document. The report signals that grid-forming is moving toward a de facto baseline for new storage projects above 1 MW across Europe. Germany has moved furthest toward commercial implementation, launching a synthetic inertia service market from January 2026 with fixed-price contracts of between two and ten years available to certified grid-forming BESS under VDE FNN technical requirements. Native GFM capability is becoming a qualification question in Germany and is likely to follow in further European markets as the NC RfG 2.0 process advances.

UniQube targets LDES applications and 2000V system evolution

UniQube is Nidec Conversion’s new high-density PCS platform, manufactured in Europe and built on a liquid-cooled IGBT architecture. Its design target is long-duration energy storage applications requiring between two and eight hours of discharge duration, alongside renewable integration for photovoltaic and hydrogen systems. At Intersolar Europe, Nidec Conversion demonstrated a complete integrated configuration: two UniQube units paired with a Ring Main Unit and medium-voltage transformer, delivering 10 MVA total at 5 MVA per PCS unit.

The platform currently supports system voltages up to 1500V for PV and hydrogen applications, and its architecture has been engineered for future compatibility with 2000V systems. That voltage level is not yet standard in the market, but it is the direction several large-scale project developers are planning toward. The outdoor installation form factor and high power density, which Nidec Conversion says reduces overall project footprint, address site constraint pressures that are increasingly common in grid-scale development.

Together, ACBOX V4 and UniQube give Nidec Conversion a full-stack European BESS and power conversion offer at the point where grid code requirements are raising the technical floor for storage. Independent verification of the efficiency improvements Nidec Conversion attributes to the SiC architecture, and formal grid-forming certification under national TSO programmes, will be the markers that convert a strong launch into a commercial position.

Stay ahead in the electrification revolution. Explore more breakthroughs from leading innovators in electric commercial transport – visit our news page.