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Products & Services - Acelo SST

Acelo SST

Not a transformer that steps voltage down. A system that controls it.

  • SiC MOSFET and high-voltage IGBT based
  • In-house topologies — MMC, DAB, CHB, AFE
  • AI-based optimal voltage prediction
Acelo SST

Problem

AI load breaks the assumptions distribution was designed around.

NVIDIA's Hopper generation drew about 700 W per H100 GPU, roughly 10 kW for a two-CPU, eight-GPU system. A GB200 NVL72 rack with 36 CPUs and 72 GPUs draws around 132 kW. The load did not grow — it changed category. Conventional distribution assumes a load that is broadly steady and broadly predictable, and AI compute is neither.

Challenge

Why a conventional transformer becomes the bottleneck.

  1. 01

    Mass and footprint

    Iron and copper scale with capacity. Beyond a point the power room, not the compute, sets the limit.

  2. 02

    Too many conversion stages

    Existing systems pass power through several inefficient AC-DC conversions before it reaches the load. Each stage costs efficiency and adds a failure point.

  3. 03

    No control surface

    There is nothing to tune. Output follows input, and the system has no say in between.

Technology

Power electronics we built ourselves.

Acelo SST controls voltage and power quality using SiC MOSFET and high-voltage IGBT devices, our own conversion topologies — MMC, DAB, CHB and AFE — and high-frequency isolation transformer design. That combination delivers sub-second real-time control and precision below 1 V, which fixed equipment cannot do, so optimal energy reaches the load with no lead time.

AI optimal-voltage prediction

The AI controlling Acelo SST collects and analyses data from every load and power node on site, predicts the optimal voltage and power-quality coefficients — power factor, harmonics — and controls them automatically. It learns how voltage behaviour differs by equipment type across industries, so operation is optimised with minimal impact on the equipment itself.

First to commercialise SST

Acelo SST Hybrid is an industry-leading case of SST technology brought to market. Voltage optimisation cuts electricity consumption on industrial sites by an average of 5%, and the equipment is certified under the external carbon-credit methodology, so those savings can be recognised as carbon credits.

How it works

Four stages, one controlled path.

01

Input

Medium-voltage AC arrives from the grid — including generation that is variable by nature, such as solar.

02

Semiconductor conversion

SiC MOSFET and IGBT stages switch at 10 kHz. This is where the magnetic mass of a conventional transformer is traded for control.

03

Regulated output

The uneven input is levelled — voltage control accuracy within ±0.1%, compensation range ±10%. What reaches the load is steadier than what entered the device.

04

AI control and monitoring

The AI predicts the optimal voltage from load data and adjusts while running, reporting upstream over Modbus TCP/IP rather than being inferred from symptoms.

INPUTREGULATED OUTPUTGRIDSOLARACELO SSTLOADCONTROL · MONITORINGDATA

Conceptual diagram of input variability against regulated output — not measured data.

Line-up

Three variants, one platform.

Acelo SST Hybrid

100 kW / 200 kW · 500 kVA

Acelo SST Hybrid

High-quality, high-efficiency power without replacing the existing transformer.

Features

  • Operates alongside the existing transformer
  • Precise secondary-side voltage control
  • Real-time voltage compensation
  • Improves voltage drop and fluctuation
  • Energy saving from AI optimal-voltage prediction
  • Power-factor correction and reactive power compensation

Outcome

  • Minimised voltage variation, stable supply
  • Energy saving through voltage optimisation
  • Better power quality, equipment protection

Patents

  • Distribution transformer voltage control device 10-2687785 [Registered]
  • Distribution system control using a distribution transformer voltage control device 10-2745498 [Registered]
  • Single-phase independent control device for three-phase voltage stabilisation and neutral current reduction 10-2025-0105723 [Filed]
Acelo SST DC800

800 V DC · 1 MW

Acelo SST DC800

A new power architecture for lowering the total cost of ownership of an AI data center.

Features

  • Single-stage conversion architecture
  • Medium-voltage AC converted directly to 800 V DC
  • Bidirectional power flow control
  • ESS integration and power buffering
  • Fast voltage control for swinging GPU load
  • High power-density supply

Outcome

  • Fewer conversion stages, lower losses
  • DC-based infrastructure cuts equipment space by 40–50%, TCO by about 30%, and maintenance cost by up to 70%
  • Stable voltage even under rapidly changing GPU load

Patents

  • High-voltage DC power conversion device for rapidly varying loads such as GPUs 10-2025-0173219 [Filed]
Acelo SST SOP

AC · 500 kW

Acelo SST SOP

Active power-flow control between distribution feeders.

Features

  • Active power-flow control
  • Reactive power compensation
  • Harmonic reduction and power-quality improvement
  • Bidirectional power flow control
  • MVDC supply
  • Fault isolation and uninterrupted transfer

Outcome

  • Redistributes power between overloaded and spare feeders, improving grid efficiency and utilisation
  • Better voltage stability where renewables connect
  • Blocks propagation of voltage variation and faults between feeders
  • Continuity of supply through uninterrupted transfer

Patents

  • Power conversion device with dual-switch structure and control method 10-2975902 [Registered]
  • Power conversion device with partial-discharge diagnosis 10-2975905 [Registered]
  • Power conversion device using renewable-energy forecasting and control method 10-2025-0107234 [Filed]

Deployment

Fits the room you already have.

01

Smart Retrofit

Connects on the secondary side without removing the existing main transformer. No large-scale grid replacement work, so no downtime and no disruption to operations — and far lower initial capital expenditure than a full replacement with global-vendor SST equipment.

02

All-in-One

A single form factor instead of separate AHF, AVR and capacitor banks taking up electrical-room space. One unit performs power-factor correction, harmonic control and voltage-unbalance control together, which simplifies maintenance to a single point.

03

Dynamic CVR

Overcomes the limit of hardware that only holds a manually set static voltage. An intelligent grid brain analyses load patterns and determines the optimal voltage on its own, with 0.1% control error against the target.

up to 13%

Energy saving

reduction in electricity cost

up to 80 t

Carbon reduction

basis for carbon-credit linkage

0.1%

Voltage control

control error

Per unit, from the Acelo SST Hybrid (500 kVA) brochure.

Application

Where it goes.

  • AI data centers

    800 V DC distribution for high-density compute.

  • Renewable integration

    Levelling variable generation.

  • Manufacturing

    Rubber, steel pipe and similar processes.

  • Commercial & institutional buildings

    Urban commercial and educational facilities.

See deployment cases

Specifications

Acelo SST Hybrid · 500 kVA

Values below are printed in the Acelo SST Hybrid (500 kVA) brochure. Specifications for DC800 and SOP are published once confirmed.

01

Rating

Rating
Rated capacity500kVA
Rated input voltage3-phase 380Vrms
Input voltage range342 – 418Vrms
Output voltage range±10% adjustable within input range
Rated input currentapprox. 76Arms
Rated output currentapprox. 760Arms
02

Control performance

Control performance
Control frequency10kHz
Voltage control accuracywithin ±0.1%
Voltage compensation range±10%
ResponseReal-time voltage control
03

Power quality

Power quality
Efficiency97 or above%
Power factor0.99 or above
Power-factor correctionSupported (optional)
Harmonic controlSupported (optional)
Voltage unbalance controlSupported (optional)
Voltage sag compensationSupported (optional)
04

Communication & monitoring

Communication & monitoring
Upstream communicationTCP/IP Modbus
Internal communicationCAN
HMI communicationRS485
HMI7-inch touch LCD
Remote monitoringSupported (AI cloud integration available)
05

Protection

Protection
Overvoltage protectionSupported
Overcurrent protectionSupported
Over-temperature protectionSupported
Emergency stopSupported
BypassSupported
06

Environment & mechanical

Environment & mechanical
Applicable standardBased on IEC 62477-1
Protection ratingIP44
Operating temperature−20 to +45℃
Relative humidity0 – 95 RH (non-condensing)%
CoolingForced air
InstallationStand-alone
Weightapprox. 500kg

Common questions

What is a solid-state transformer?
Where a conventional transformer simply converts voltage, a solid-state transformer controls voltage, current and power flow in real time using semiconductor switching. Because conversion is switched rather than fixed, the device can regulate its output and report its state while operating.
Why do AI data centers need solid-state transformers?
NVIDIA has proposed 800 V DC as the architecture for next-generation data centers, with SST as the key equipment for realising it. At the same wire gauge, 800 V DC carries 157% more power than conventional AC infrastructure, which lowers infrastructure cost; it removes the several inefficient AC-DC conversion stages of existing systems; and it makes transformers and phase-balancing equipment unnecessary, reducing system complexity and potential failure points.
What is the difference between Acelo SST Hybrid, DC800 and SOP?
Hybrid operates alongside an existing transformer and precisely controls the secondary-side voltage, so a site can improve power quality and save energy without replacing its main transformer. DC800 converts medium-voltage AC directly to 800 V DC for data centers and other DC loads. SOP is applied at the normally-open point between distribution feeders to actively control active power, reactive power and voltage between them.
Can an SST be installed without replacing the existing transformer?
Yes. Acelo SST Hybrid connects on the secondary side of the existing main transformer, so no removal is required. Because there is no large-scale grid replacement work, downtime and disruption to operations are avoided, and the initial capital expenditure is far lower than a full replacement.
Can an SST help with renewable energy variability?
Yes. Generation such as solar varies through the day. Solid-state conversion levels that variability before it reaches the load, so the downstream system sees a steadier supply than the source provides.

Related products

Talk to our engineering team.

Tell us the application, the voltage level and the timeline.

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