Linear Motor Continuous Force Rating vs Peak Force Trade-off

Overview of Technical Issues:

The force generation mechanism in the linear motor exhibits insufficient capability to simultaneously deliver high continuous force rating for sustained operations and high peak force for dynamic responses—when optimized for continuous duty, peak force becomes inadequate for transient loads, while peak-force optimization results in insufficient continuous rating due to thermal accumulation constraints from the thermal dissipation structure; the goal is to overcome this trade-off and achieve both high continuous force rating and robust peak force capability without thermal limitations.

Solution directions generated for this problem

Problem Direction 1 :

ImproveContinuous force output capacity
VS
ConstraintHeat generation rate

Inspiration 1 : Cross-domain reference

Application Principle: #35 Parameter changes
Cross-domain applicability Assess applicability
Ultrasonic sealing method and device for bags
Innovative Solution Refine solution

Cryogenic conductor pre-conditioning for continuous force enhancement

Cryogenic pre-treatment reduces winding resistance
How to solve :
  • Pre-cool motor windings to -40°C to -60°C using liquid nitrogen circulation before continuous operation — copper resistivity drops 25-30% at cryogenic temperature, enabling same force with lower I²R losses
  • Install vacuum-insulated cooling jacket around winding assembly with LN₂ inlet/outlet ports (flow rate 0.5-1.0 L/min) — maintain winding at -50±5°C during 10-15 minute pre-conditioning phase, then switch to ambient operation as thermal mass absorbs heat
  • Integrate resistance monitoring circuit (±0.1% accuracy) to verify winding resistance reduction ≥22% before engaging continuous duty — if resistance target unmet, extend pre-cooling by 3-5 minutes to ensure thermal uniformity across all coil layers
Expected Effect : Continuous force +35-40% at same thermal limit; I²R losses -28%
Risk Control :
  • LN₂ supply logistics and cost
  • thermal shock-induced insulation micro-cracking
  • condensation moisture ingress risk

Problem Direction 2 :

ImproveContinuous force output capacity
VS
ConstraintThermal management system complexity

Inspiration 1 : Cross-domain reference

Application Principle: #25 Self-service
Cross-domain applicability Assess applicability
System and method for magnetization of rare-earth permanent magnets
Innovative Solution Refine solution

Motion-driven passive coolant circulation in linear motor housing

Integrate motor motion to drive coolant flow
How to solve :
  • Machine bidirectional flow channels into motor housing walls with check valves at each end — linear motion creates pressure differential that pumps coolant without external pumps
  • Fill channels with dielectric coolant (3M Novec 7100, boiling point 61°C) at 70–80% volume — motion-induced flow rate 0.15–0.25 L/min per 100mm stroke at 1Hz frequency
  • Bond aluminum nitride heat spreader (thermal conductivity ≥200 W/(m·K), thickness 0.6mm) directly to winding backing plate — transfers heat to channel walls within 15mm distance, eliminating separate heat sink assemblies
Expected Effect : Continuous force +35%, zero active cooling components, system mass −18%
Risk Control :
  • check valve reliability under vibration
  • coolant leakage at channel seals
  • flow rate insufficient at low motion frequency

Problem Direction 3 :

ImprovePeak force output capacity
VS
ConstraintHeat generation rate

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Substrate transfer device, and vacuum treating apparatus
Innovative Solution Refine solution

Pre-staged capacitor bank for decoupled peak force delivery

Decouple peak force from resistive heating via energy pre-storage
How to solve :
  • Install electrolytic capacitor bank (500–1200 μF, 400–600 VDC) charged continuously at low current during normal operation
  • capacitor discharges 2.5–3× nominal current for 50–200 ms peak events, bypassing winding resistance during transients
  • IGBT switching circuit (10 kHz PWM) controls discharge timing with ±2 ms precision, triggered 5 ms before mechanical peak demand
  • winding experiences only capacitor's low-ESR path (typically 15–30 mΩ vs. winding 200–500 mΩ), reducing I²R losses by 65–75% during peak phase
  • capacitor recharges over 3–8 seconds at 0.3–0.5C rate between peaks, thermal load distributed across duty cycle rather than concentrated in transient
Expected Effect : Peak I²R losses -70%, peak force +40%, thermal spike eliminated, continuous rating unaffected
Risk Control :
  • capacitor ESR drift over temperature cycles
  • IGBT switching loss accumulation
  • discharge synchronization timing error

Problem Direction 4 :

ImproveContinuous force output capacity
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Deformable element
Innovative Solution Refine solution

Pre-cooled thermal reservoir motor with phase-transition buffer for dual-mode force output

Pre-cool motor to sub-ambient temperature before operation to create thermal capacity reservoir
How to solve :
  • Install thermoelectric cooling module (TEC, Peltier array 200–300W capacity) on motor housing
  • pre-chill windings and core to -10°C to -15°C for 3–5 minutes before duty cycle starts, creating 8–12 kJ thermal absorption capacity
  • Embed phase-change material (PCM) packets (paraffin wax, melting point 55–65°C, latent heat ≥180 kJ/kg) in 0.6mm aluminum foil envelopes between winding layers, absorbing transient heat spikes during peak force events without temperature rise
  • Operate in time-division thermal mode: continuous phase uses stored cold capacity (winding temperature rises from -10°C to +80°C over 60–90 seconds), peak phase triggers PCM melting to buffer 2–3x current bursts, idle phase (10–15 seconds) allows PCM solidification and TEC re-cooling to baseline
Expected Effect : Continuous force duration +70%, peak force capability +85%, no active cooling during operation
Risk Control :
  • TEC power consumption adds 15–20% energy overhead
  • PCM packet placement precision affects thermal uniformity
  • condensation risk at sub-zero pre-cooling requires sealed housing
Patsnap Eureka Solution