Linear Motor Forcer Cooling Channel Design for Peak Power

Overview of Technical Issues:

The cooling channel structure provides insufficient heat removal from the linear motor forcer during peak power operation, causing excessive temperature rise in the windings that leads to thermal derating, performance degradation, and risk of insulation damage; the goal is to optimize the cooling channel design to maintain safe operating temperatures even during peak power pulses while managing thermal transients effectively.

Solution directions generated for this problem

Problem Direction 1 :

ImproveCoolant flow velocity
VS
ConstraintPressure drop and pumping power

Inspiration 1 : Cross-domain reference

Application Principle: #15 Dynamics
Cross-domain applicability Assess applicability
System and method for processing liquefied gas
Innovative Solution Refine solution

Adaptive pulsed cooling with predictive flow modulation for linear motor thermal management

Adaptive flow control matches cooling intensity to real-time thermal demand
How to solve :
  • Install variable-speed pump with winding-embedded RTD temperature sensors (±0.5°C accuracy, 50ms response) feeding PID controller
  • baseline flow 1.5 L/min at 80°C, ramps to 6 L/min when temperature exceeds 140°C threshold
  • Implement predictive algorithm using motor controller CAN bus data to pre-boost flow 2–3 seconds before scheduled peak power events, pre-cooling windings to 120°C baseline for thermal headroom
  • Deploy dual-threshold control: aggressive ramp (0–100% in 0.8s) at 145°C for emergency response, gradual modulation (±15% per second) at 130–145°C for efficiency
  • pressure sensors verify flow within ±8% of setpoint
Expected Effect : Average pumping power reduced 60–70%; peak winding temperature maintained below 148°C; thermal response time under 1.2s
Risk Control :
  • sensor calibration drift over thermal cycles
  • pump cavitation during rapid acceleration
  • controller latency causing temperature overshoot

Problem Direction 2 :

ImproveHeat exchange surface area
VS
ConstraintForcer volume and weight

Inspiration 1 : Cross-domain reference

Application Principle: #17 Another dimension
Cross-domain applicability Assess applicability
Cylindrical air to air heat exchanger
Innovative Solution Refine solution

Radial microchannel array embedded in winding bobbin core

Embed radial microchannel array in bobbin core
How to solve :
  • Machine radial microchannel arrays (0.6–0.8mm diameter, 2–3mm pitch) directly into hollow winding bobbin cores using precision EDM drilling, creating 3D coolant pathways perpendicular to heat flow direction without adding external cooling layers
  • Use high-conductivity aluminum alloy 6061-T6 (thermal conductivity ≥167 W/(m·K)) for bobbin material, with manifold ports at axial ends distributing coolant radially through 50–80 parallel microchannels per bobbin section
  • Implement serpentine radial flow pattern where coolant enters central manifold, flows radially outward through microchannels to winding contact surface, returns through interleaved channels, achieving 8–12× surface area multiplication within existing bobbin volume
Expected Effect : Heat exchange area +850%, forcer volume +0%, winding temperature reduced to 135°C at peak power, thermal resistance <0.15 K/W
Risk Control :
  • microchannel blockage from coolant contamination
  • EDM drilling tolerance deviation ±0.05mm affecting flow uniformity
  • thermal expansion mismatch between aluminum bobbin and copper windings causing interface gaps

Problem Direction 3 :

ImproveThermal transient response capability
VS
ConstraintForcer volume and weight

Inspiration 1 : Cross-domain reference

Application Principle: #35 Parameter changes
Cross-domain applicability Assess applicability
High damage threshold frequency conversion system
Innovative Solution Refine solution

Phase-change material thermal buffer layer for transient peak absorption

Embed PCM layer to absorb transient heat without adding thermal mass
How to solve :
  • Integrate 0.6mm thin PCM layer (paraffin wax composite, melting point 145–150°C, latent heat ≥200 kJ/kg) directly between winding and cooling channel using aluminum foam carrier (porosity 85–90%, thermal conductivity ≥180 W/(m·K)) to maintain structural integrity while enabling phase transition
  • During peak power pulses (5–15 seconds), PCM absorbs heat through solid-liquid phase change, buffering temperature spikes by 25–35°C without requiring increased coolant flow
  • between pulses, standard cooling solidifies PCM for next cycle
  • Encapsulate PCM in sealed aluminum cells (wall thickness 0.15mm) to prevent leakage and volume expansion, with thermal interface resistance <0.02 K·cm²/W to winding surface
  • quality control via differential scanning calorimetry (DSC) verifying latent heat ±5%, melting range ±3°C
Expected Effect : Transient temperature spike reduced 30°C; forcer volume increase <2%; thermal response time improved 40%
Risk Control :
  • PCM thermal cycling degradation after 10,000 cycles
  • encapsulation seal failure under vibration
  • thermal contact resistance drift over time

Problem Direction 4 :

ImproveHeat transfer coefficient
VS
ConstraintPressure drop and pumping power

Inspiration 1 : Cross-domain reference

Application Principle: #3 Local quality
Cross-domain applicability Assess applicability
Battery cell thermal runaway barrier
Innovative Solution Refine solution

Spatially-graded microchannel cooling with localized turbulence zones

Divide channels into zones with turbulence only where heat flux peaks
How to solve :
  • Segment cooling channels into three thermal zones: smooth laminar channels (heat flux <50 kW/m²), moderate dimpled sections (50-80 kW/m²), and aggressive pin-fin arrays only at end-turn windings (>80 kW/m²) where temperature exceeds 180°C
  • Design hydraulic diameter transitions from 3mm smooth to 1.5mm finned sections with gradual contraction angles ≤15° to minimize separation losses
  • Install inline pressure sensors (±0.5% accuracy) at zone boundaries to verify pressure drop remains below 25 kPa total while achieving local heat transfer coefficient >8000 W/(m²·K) in critical zones
Expected Effect : Heat transfer +120% in hot zones, system pressure drop +18% only, pumping power +22%
Risk Control :
  • zone transition flow separation
  • manufacturing tolerance of micro-features
  • thermal expansion mismatch between zones

Problem Direction 5 :

ImproveThermal transient response capability
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Rotary tilting electric crucible furnace
Innovative Solution Refine solution

Pre-cooling thermal buffer system with predictive control for transient response

Predictive pre-cooling before peak power events
How to solve :
  • Install temperature-predictive controller linked to motion planner — initiates pre-cooling 15–30 seconds before scheduled peak power operations, reducing winding baseline temperature from 140°C to 100–110°C to create thermal headroom
  • Integrate fast-response microchannel array (channel diameter 0.8–1.2mm, hydraulic diameter ≤1.5mm) with coolant flow rate ramping from 2 L/min baseline to 8 L/min during pre-cooling phase, achieving heat transfer coefficient ≥3000 W/(m²·K)
  • Embed thin-film RTD sensors (response time ≤50ms) at winding hot spots with closed-loop feedback — controller maintains winding temperature below 150°C during peak pulses by modulating flow rate in real-time based on predicted thermal load from motion commands
Expected Effect : Winding peak temperature ≤148°C; thermal headroom +30–40°C; response time <100ms
Risk Control :
  • motion prediction accuracy insufficient causing mistimed pre-cooling
  • microchannel clogging from coolant contamination
  • sensor calibration drift under thermal cycling
Patsnap Eureka Solution