Technology Platform

iNERGY-Drive™
FOC Technology

Precise. Smooth. Quiet. Intelligent. The Heart of Smart Cooling. Proprietary Field-Oriented Control embedded in iU6xxx ICs — delivering unmatched motor performance across all load conditions.

Self-Learning Algorithm 120,000 RPM Capability 4KHz Electrical Frequency ±15% Coil Tolerance
iNERGY-Drive™ FOC

Field-Oriented Control:
The inergy Advantage

Traditional 120° square-wave drive wastes energy through torque ripple, commutation noise, and suboptimal current phasing. iNERGY-Drive™ FOC delivers sinusoidal current at the optimal phase angle — maximizing torque-per-ampere across all speeds.

Up to 120,000 RPM
4KHz electrical frequency control capability. With a 4-pole motor: 4,000Hz / 2 pole-pairs × 60s = 120,000 RPM. Validated on 12V 4028 server fan at 41000 RPM.
4KHz Electrical Freq · 4-Pole · 12万RPM
🧠
Self-Learning Algorithm
Automatically identifies motor parameters and optimizes the operating point. Adapts to load variation, back pressure changes, and manufacturing tolerances — no manual tuning required after initial setup.
Auto-Optimize · Zero Iteration
📈
+3.3–11.6% Efficiency
Validated competitor comparison: iU6291 outperforms leading competitor by 11.6% at PWM=20%, 9.6% at PWM=60%, and 3.3% at PWM=100%. Coil temperature 5°C lower after 60 minutes.
vs Leading Competitor · Validated
🔧
±15% Coil Tolerance
When coil resistance and inductance vary ±15% from nominal (common in mass production), FOC auto-corrects to reach the same target speed — IDC increase only 1.7–5.8%.
Production-Robust · No Re-tune
📐
Lead Angle Control
Adjustable lead angle — positive (advance), negative (lag), and zero-crossing crossing. Critical for optimizing efficiency at specific operating speed ranges. Positive and negative angles validated.
Positive / Negative / Zero-Crossing
🔇
Sensorless & Silent
Hall sensor not required — iNERGY-Drive™ FOC achieves full sensorless control. Smooth sinusoidal currents eliminate commutation noise. Low acoustic noise critical for AI rack density.
No Hall Required · Low EMI
System Test Results

iU6391 FOC System Performance

Validated on 12V 4-pole motor, 37,000 RPM operating point. All results from inergy internal testing using real fan motors with Tektronix oscilloscopes. These FOC results carry across the iNERGY-Drive™ platform — for new 12V high-current designs the iU6395 (N/N pre-driver, dual integrated current-sense amplifiers) is the recommended successor.

#Test CategoryResultDetail
1FOC vs 120° Square Wave (Sine Magnetization)Better @ 7K–20K RPMFOC efficiency exceeds 120° square wave in 7,000–20,000 RPM range
2FOC vs 120° Square Wave (Square Magnetization)Better @ 8K–22K RPMFOC efficiency exceeds 120° square wave in 8,000–22,000 RPM range
3Efficiency Under Different Fan LoadsAuto-OptimizeFOC automatically optimizes efficiency across light, medium, and heavy fan loads
4Lead Angle AdjustmentFull RangePositive, negative, and zero-crossing lead angle all validated and controllable
5Coil Parameter Variation ±15%IDC +1.7–5.8% onlyR±15%, L±15% — FOC auto-corrects to reach same target speed, minimal efficiency loss
6Motor Startup — Zero SpeedPassSmooth startup from standstill in all static conditions
7Motor Startup — Tailwind (Forward)PassDirect speed catch-up from 2,150 RPM forward free-run
8Motor Startup — Reverse WindPassBrake to stop then smooth forward start from 2,080 RPM reverse spin
9High Speed Control — FOC Max120,000 RPM4KHz electrical frequency → 4-pole motor → 120,000 RPM theoretical capability
10Terminal ProgrammingPass4-wire burn-in via VDC/PWM/FG/GND without disassembling motor/fan
Efficiency Comparison · iU6291 vs Competitor

Validated Efficiency Advantage

Tested on 12038 fan, 12V, same speed setpoint. iU6291 consistently draws less current than the leading competitor at every PWM duty level.

PWM Duty vs Efficiency Comparison (12038 Fan, 12V)
PWM%Competitor RPMCompetitor IDC (mA)iU6291 RPMiU6291 IDC (mA)IDC ReductionEfficiency Gain
20%19381731933153-20 mA+11.6%
40%32374263251389-37 mA+8.7%
60%45039414516851-90 mA+9.6%
80%5858185258521742-110 mA+5.9%
100%7061313470023032-102 mA+3.3%
Temperature Validation — 60 Minutes Continuous
At 7,000 RPM continuous operation (25°C ambient, 60 minutes): Competitor coil temperature 43.2°C — iU6291 coil temperature 38.7°C. A 4.5°C improvement in coil temperature directly extends motor life and improves system MTBF.
Startup Capability

All-Condition Startup

AI datacenter fans and pumps must start reliably regardless of airflow or coolant flow conditions at power-on. iNERGY-Drive™ FOC handles all three critical scenarios.

🛑→▶️
Scenario 1
Zero-Speed Startup
Motor at rest. iNERGY-Drive™ FOC detects static rotor position and applies controlled startup current ramp. Smooth acceleration to target speed in ~5 seconds (KP/KI tunable).
Static StartSmooth Acceleration
🌬️▶️
Scenario 2
Tailwind / Forward Flow Startup
Fan/pump already spinning in forward direction from airflow or coolant flow. FOC detects rotor speed and phase, then performs direct speed catch-up — no braking required.
Speed DetectionDirect Catch-Up
↩️▶️
Scenario 3
Reverse Wind / Back-Flow Startup
Fan spinning in reverse from negative pressure (common in rack hot-aisle conditions). FOC detects reverse rotation, applies controlled brake, then smoothly starts in forward direction.
Reverse DetectionAuto-BrakeForward Start
Motor Control Platform

iNERGY Motor Control Platform

inergy's platform combines the best of ASIC simplicity and MCU flexibility — delivered as a complete solution with IC + motor control firmware + S Programmer tool.

🔲
ASIC Approach
Simple customer tuning, but limited customization. Cannot change fundamental behavior.
Advantage: Easy to use
🎯
iNERGY-Drive™ Platform
Combines both: easy 1-click parameter generation + flexible firmware base + dedicated S Programmer tool. Convenient · Reliable · Efficient · Flexible.
Best of Both Worlds
💻
MCU Approach
Maximum flexibility but high development difficulty, time, and cost. Requires significant engineering resources.
Advantage: Flexible
📊
Excel Parameter Table
Users fill in motor operating parameters in a structured Excel table. "One-click generate" produces the parameter file — no firmware coding required.
🔧
S Programmer Tool
inergy's dedicated S Programmer hardware flashes the generated parameter file via 4-wire connection (VDC/PWM/FG/GND). No motor disassembly needed.
📄
Motor Control Firmware Base
Fully tested iNERGY-Drive™ firmware base handles all FOC algorithms. Customer parameters customize behavior — not rewrite the core.
🔁
4-Wire Production Burn-In
Same 4-wire terminal interface used for parameter flash is available in production. Enables in-line programming without fan/motor disassembly.
// Start your iNERGY-Drive™ evaluation

Get iNERGY-Drive™ FOC
Development Kit

EVB, S Programmer, parameter generation Excel tool, and reference firmware included. FAE remote fine-tune session included for rapid motor optimization.

Company