Axiom, A 100+kW Motor Controller For Making Big Motors Move

If you’ve ever driven a tiny drone motor with a pocket-sized ESC, you already understand the basic magic trick:
take DC power, chop it up into three phase-shifted waveforms, andboomspinning happens. The difference with
Axiom is that the “boom” is purely metaphorical (please keep it that way). We’re talking about a
100+ kW-class motor controller aimed at moving big motorstraction motors, industrial machines,
R&D rigs, and the sort of projects where “continuous current” isn’t a footnote… it’s the whole story.

In the open-hardware world, Axiom gained attention because it’s built around a bold idea:
make high-power motor control more accessible without sacrificing the engineering discipline that
keeps high-voltage systems reliable and predictable. It’s also notable for being
VESC-compatible, which means it inherits a familiar ecosystem of tooling and workflows that many
builders already trustonly now scaled up to a power level where the motor can stop being “cute” and start being
“seriously productive.”

What “100+ kW” Actually Means (In Human Units)

Power ratings can get abstract fast, so let’s translate. 100 kW is about 134 horsepower. In EV terms,
that’s “commuter car” territory. In industrial terms, it’s “this pump doesn’t care about your feelings” territory.
But the trick is that high power comes from some combination of voltage and current, and those two numbers dictate
everything about the hardware.

Quick math, big implications

• 100 kW at 400 V is about 250 A.
• 300 A at 400 V is 120 kWand that’s “all day long” power if the thermal design can keep up.
• 100 kW at 48 V would require over 2,000 A, which is why low-voltage, high-power builds quickly turn into copper-and-cooling sculptures.

This is why Axiom’s widely discussed target of high current at high voltage matters: it lives in the zone where EV
traction inverters operate, and where electrical noise, switching losses, thermal limits, and safety margins stop
being “nice-to-haves” and start being “either you respect physics or physics will file a complaint.”

Meet Axiom: Big-Motor Control With Open Roots

Axiom is best understood as a high-power three-phase inverter and controller designed to run serious
motors while staying compatible with the VESC ecosystem. In plain English: it’s an EV-grade style
controller philosophy applied with open design intent, using proven motor-control ideas and a familiar interface
for configuration, monitoring, and tuning.

The “why” is compelling. High-power motor control is historically gated behind expensive commercial controllers,
proprietary software, and limited visibility into the details that matter (fault handling, measurement fidelity,
control timing, hardware protection logic). Axiom’s approach is basically: “What if the community didn’t have to
reinvent the wheel, but could finally see how the wheel is made?”

What it’s designed to do

The Axiom project description frames it as a controller intended for powerful three-phase motors across diverse
applicationseverything from traction vehicles and racing to industrial use and R&D environments. It’s also been
discussed in contexts like subsea systems and other specialized platforms where dependable torque control matters.
That variety is a clue: Axiom isn’t just chasing peak power; it’s chasing control quality and
system integration at high power.

Under the Hood: The Three Pieces Every High-Power Controller Must Nail

If you strip away the branding and the hype, every high-power motor controller lives or dies by three fundamentals:
(1) power switching, (2) measurement and isolation, and (3) control software that behaves under stress.
Axiom is interesting because it leans into all three instead of pretending that only one of them matters.

1) Power stage: where electrons do heavy lifting

The power stage is the muscle. It’s the part that takes DC bus voltage and produces a controlled three-phase output.
High-power designs commonly use IGBT modules or wide-bandgap devices (like SiC MOSFETs) depending on voltage,
switching frequency, efficiency targets, and packaging constraints. Axiom’s published materials and component examples
show a design approach compatible with high-current IGBT modules and robust gate drivingexactly what you’d expect
for a controller aiming at continuous high power without drama.

Why modules? Because at hundreds of amps, discrete transistors become a layout and reliability puzzle. Modules help
with current sharing, thermal paths, and repeatable assembly. But “help” doesn’t mean “easy.” It means your problems
become more professional. Congratulations.

2) Sensing + isolation: the part that keeps your measurements honest

High-performance motor control depends on accurate current and voltage feedback. And that’s annoyingly difficult in
an inverter, because the very act of switching power creates huge dv/dt and di/dt events that try to inject noise
into everything. Industrial motor-drive design guidance often emphasizes that phase current sensing lives in a harsh,
electrically noisy environmentand it’s not trivial to measure well without careful isolation and layout choices.

Practically, this is why you’ll see hall sensors or shunts with isolated amplifiers, isolated power rails for gate
drivers and measurement domains, and communication interfaces designed to survive EMI. The goal is simple:
your controller should “see” the motor clearly even when the inverter is throwing a tiny lightning
storm at the PCB.

3) Control brain: fast timing and predictable protection

Axiom is frequently described as combining a microcontroller-driven control flow with additional logic resources.
In high-power systems, “the brain” isn’t just about torque control; it’s also about how faults are detected and how
quickly the system can react. Hardware-accelerated logic can be useful for safety-related timing, interlocks, or
signal conditioning that must behave deterministicallyeven if the CPU is busy.

The fun part is that this isn’t just academic. At 100+ kW, a fault response measured in microseconds can be the
difference between “caught it” and “why does my garage smell like regret?”

FOC: The Not-So-Secret Sauce That Makes Big Motors Feel Civilized

If you’ve heard “field-oriented control” (FOC) described as “smooth torque,” that’s true… but incomplete. FOC is a
control method that treats the motor like a system you can model and steer, rather than a mystery you poke with PWM
until it spins. Done well, FOC enables:

• Fast torque response (useful for traction and robotics)
• High efficiency across operating conditions
• Controlled regenerative braking (turning decel energy into returned battery energy, within limits)
• Consistent behavior when load changes suddenly

TI and other motor-control references commonly frame traction inverters as the bridge between a high-voltage battery
and a multi-phase AC machine, including both propulsion and regeneration. Microchip’s motor-control reference designs
similarly highlight FOC for efficiency and noise reduction. The point isn’t the brandit’s the consensus:
modern high-performance drives are control-software products as much as they are power hardware.

Regenerative braking: powerful, but not “free”

Regen is a great feature, but it has constraints: battery charge limits, bus voltage limits, thermal limits, and
traction stability. The controller must enforce boundaries so regen doesn’t overvoltage the system. Industry
specifications for hybrid/electric vehicle systems have long emphasized that controller/inverter functions should
manage battery voltage limits, including during regeneration.

Translation: the best motor controller isn’t the one that regenerates the most; it’s the one that regenerates
appropriately while staying stable, safe, and predictable.

Thermal Reality: “All Day Long” Is a Cooling Statement

At high power, the hard part isn’t making a motor spin. The hard part is making it spin for hours without drifting,
derating, or cooking the components that quietly age faster at elevated temperatures. Research organizations like
NREL spend a lot of effort on power electronics thermal management and packaging reliability because temperature
doesn’t just affect the semiconductorit affects capacitors, boards, interconnects, and long-term durability.

Where the heat comes from

• Conduction losses: current through devices and busbars produces I²R losses.
• Switching losses: every on/off transition costs energy, more so at high voltage and current.
• Magnetics and filters: inductors and EMI components dissipate real heat too.

When a controller claims a high continuous rating, it’s really claiming that the mechanical and thermal design
(heat sinking, coolant interface if used, airflow assumptions, temperature sensing placement) can keep the critical
parts within spec. That’s why datasheets and real testing matter more than optimistic forum math.

Safety and Standards: The Boring Part That Keeps Things Un-boring

High voltage systems don’t need scary marketing; they’re inherently serious. Guidance aimed at responders and
post-incident handling of high-voltage EVs repeatedly stresses a simple rule: assume the system is energized
unless you have verified otherwise. That mindset is useful even for engineers, because it forces you to treat
isolation, creepage/clearance, service disconnect concepts, and discharge paths as first-class design requirements.

On the industrial side, UL safety frameworks around adjustable speed drives focus on electrical and thermal safety
considerations for drive systems and their elements. Even where a specific standard may exclude traction drives,
the underlying thinkingsafe spacing, insulation integrity, predictable fault behavior, and robust design marginsis
directly relevant to any high-power controller that expects to live in the real world.

A practical safety mindset for readers

• Respect energy storage: capacitors can retain dangerous energy even after power-down.
• Design for faults: “what happens if this sensor fails?” should have a calm answer.
• Assume EMI is hostile: what works on a bench may fail next to a real busbar and switching edges.
• Use qualified expertise: high-voltage traction systems should be validated by trained professionals and appropriate procedures.

Integration: Why CAN, Tooling, and “User Experience” Matter at 100 kW

It’s easy to underestimate “software tools” until you’ve tried to tune a large motor drive without them. A core
appeal of VESC-style platforms has been the visibility: configuration interfaces, real-time plotting, logging, and
a tuning workflow that doesn’t feel like a secret handshake. Axiom leans into that idea: the interface isn’t a bonus;
it’s the difference between “I can debug this” and “I am now a full-time guesser.”

Communications like CAN are also not just buzzwords. In traction and industrial systems, a robust comms layer lets
you coordinate controllers, share torque commands, enforce limits, and integrate safety logic at the system level.
In other words: the motor controller is rarely a solo performer; it’s usually part of a larger cast.

Where Axiom Fits: Use Cases That Make Sense for a 100+ kW Controller

Axiom has been positioned as suitable for a wide spectrum of high-power three-phase motor applications. To keep this
grounded, here are a few scenarios where a 100+ kW-class controller is genuinely appropriate (and not just “because
bigger numbers are fun”):

1) EV conversions and prototype traction platforms

In conversion and prototype work, developers often need a controller that can handle a high-voltage battery pack,
provide reliable torque control, and expose configuration and telemetry for debugging. A high-power controller is
particularly useful when the goal is highway-capable performance or repeatable testing under load.

2) Racing and high-duty-cycle testing

Peak power is common in racing. Continuous power is rarerand more revealing. A controller that can sustain high
output without derating is a performance advantage not because it makes the car “faster instantly,” but because it
stays consistent lap after lap. Consistency is what turns fast parts into fast results.

3) Industrial equipment with aggressive torque demands

Heavy pumps, compressors, winches, and material-handling systems can demand serious torque at low speeds, and they
often run for long periods. High-quality current control and thermal robustness matter more than flashy peak numbers.

4) R&D rigs: dynos, test stands, and powertrain development

R&D environments value instrumentation, repeatability, and controllability. A controller designed with measurement
fidelity and tool support can shorten development cyclesbecause it helps teams isolate variables instead of guessing
at them.

Buying, Building, or Spec’ing: A Checklist for “Big Motor” Sanity

Whether you’re evaluating Axiom specifically or comparing it to other traction inverters, the selection logic is
universal. Ask these questions early, before you fall in love with a spec sheet:

Electrical fit

• DC bus voltage range: Does it match your battery or supply with margin?
• Continuous vs peak current: Are both defined with temperature conditions?
• Motor type + feedback: PMSM, induction, BLDC; Hall sensors, encoder, resolverwhat’s supported?
• Regen behavior: How are regen limits enforced and monitored?

Thermal and mechanical reality

• Cooling assumptions: air vs liquid; mounting surfaces; heat spreaders; thermal sensors.
• Packaging: busbar layout, connector strategy, creepage/clearance, environmental sealing needs.
• Component life: capacitors and interconnects often set lifetime more than semiconductors do.

Control and integration

• Tooling and logs: can you capture real data under load?
• Comms: CAN or other robust interfaces for system-level control.
• Fault strategy: graceful back-off vs abrupt shutdown; how are faults categorized and recovered?

The theme here is simple: high-power motor control is systems engineering. The controller is central, but it is not
the whole system. If you spec it like a standalone part, the rest of the system will “spec you back.”

The Direction of Travel: More Power Density, Higher Voltage, Smarter Packaging

The broader industry trend is clear: improve inverter performance while shrinking size, weight, and cost. DOE
descriptions of inverter R&D commonly emphasize reducing volume, reducing part count through integration, and
lowering costs. At the device level, wide-bandgap power (especially SiC) is frequently discussed as a route to higher
efficiency and power densityparticularly in 800 V class traction platforms. Companies like Wolfspeed and onsemi
highlight SiC modules and traction inverter architectures aimed at these higher-voltage, high-performance systems.

What does that mean for the “Axiom-style” world? Even if a given design uses IGBTs today, the pressure to move toward
higher efficiency, higher switching performance, and better thermal packaging will continue. The winners will be
designs that make these transitions without turning integration into a PhD thesis.

Conclusion: Axiom as a “Big Motor” Moment

Axiom represents a meaningful idea in the high-power motor-control space: bring traction-class capability closer to
builders and teams who value transparency, tooling, and engineering rigor. Whether you’re interested in it as a
product, a reference design, or a proof that open ecosystems can scale upward, the takeaway is the same:
high-power controllers are no longer only the domain of closed, proprietary black boxes.

And that matters because the future is full of big motorsEVs, industrial electrification, advanced mobility, and
everything in between. The more we can make high-power control understandable, testable, and approachable (without
pretending it’s “easy”), the faster innovation happensand the fewer people learn about EMI the hard way.

Field Notes: of Real-World Experience Around 100+ kW Motor Control

The first time a team moves from a “respectable” 10 kW setup to a 100+ kW controller, the emotional arc is usually
the same: confidence, excitement, confusion, humility, competence. In that order. On paper, it looks like a clean
scale-upbigger bus voltage, bigger current, bigger heat sink. In practice, the system starts behaving like a living
creature with moods, and you quickly learn which parts of your process were solid and which parts were… optimistic.

One of the earliest lessons is that noise has a personality. At low power, sloppy wiring might only
cause an occasional sensor glitch. At high power, the same wiring becomes an antenna farm. You see it in odd places:
a temperature reading that jitters only above a certain duty cycle, a comms link that drops when torque steps fast,
or a current trace that looks “hairy” exactly when the inverter is switching hardest. Teams end up becoming amateur
detectivesmoving a cable two inches, rerouting a harness, improving shielding, or adjusting filteringthen
celebrating like they just solved a mystery novel. Because they did.

The next big lesson is that thermal management is a planning skill, not just a hardware choice.
At high power, a controller doesn’t fail only because it gets hot; it fails because something near it gets hot:
a capacitor that ages faster than expected, a connector that warms and increases resistance, or a PCB region that
becomes a tiny toaster. A common “grown-up” move is adding better temperature instrumentation so you’re not guessing
where the heat is going. The goal is boring data: stable temperatures, repeatable test runs, predictable limits.

Then there’s the tuning side. A lot of teams expect FOC to feel like a single “calibrate” button. Reality is kinder
than it used to betooling is better nowbut large motors still demand respect. When torque targets are high, small
parameter errors can show up as extra heat, less efficiency, or a control loop that feels slightly “grumpy” under
sudden load changes. The best experiences tend to come from teams that treat tuning as an engineering workflow:
log data, make one change at a time, verify improvements under the same conditions, and build a record of what
worked. It’s less glamorous than guessing, but it scales.

Finally, teams learn that a 100+ kW controller is not a single componentit’s a commitment. You don’t just buy (or
build) a motor controller; you commit to good mechanical mounting, thoughtful cabling, safety procedures, and a test
approach that doesn’t rely on luck. The funny part is that once those habits click, everything else gets easier:
the system becomes calmer, debugging becomes faster, and the “big motor” stops feeling like a wild animal and starts
feeling like a well-trained athlete. Still powerful. Still serious. But finally predictable.