Motor Cooling Optimization via Reinforcement Learning

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Solution Overview

Problem

Conventional motor control systems face challenges in reducing losses and maintaining regulated temperatures in motors and cooling devices, as they primarily vary the cooling device's operation rate based on motor temperature, leading to inefficiencies and potential damage.

Innovation Solution

A machine learning apparatus that includes a state observer, determination data acquisition unit, and learner to optimize cooling device operation conditions by analyzing temperature data and loss margins, determining optimal rotational speed and coolant flow rates, and updating operation parameters using reinforcement learning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the cooling device operation rate is varied based on motor temperature, then the motor temperature is controlled, but the total losses in motor, control apparatus, and cooling device cannot be reduced

Engineering Contradiction:
Improvemotor temperatureVSAvoidtotal losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The system uses temperature sensors to detect motor and control apparatus temperatures, feeds this information back to the control unit, which then adjusts the cooling device operation rate accordingly. This closed-loop feedback mechanism enables dynamic optimization of cooling performance while minimizing energy losses.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit dynamically changes the operation rate parameter of the cooling device based on real-time temperature conditions. By adjusting this parameter according to actual thermal states of both motor and control apparatus, the system achieves optimal balance between temperature control and loss reduction.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the cooling device operates at high rate to maintain regulated temperature, then temperature control is achieved, but energy losses increase

Engineering Contradiction:
Improveregulated temperatureVSAvoidcooling device energy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The cooling device operation rate is made dynamic rather than fixed. The control unit continuously adjusts the operation rate based on real-time temperature measurements from both motor and control apparatus, enabling the system to use minimum necessary cooling power while maintaining regulated temperatures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of maintaining constant high-rate cooling, the system applies partial cooling action only when and where needed. The control unit determines the precise cooling requirement based on actual temperature margins, avoiding excessive cooling operation and associated energy losses.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the cooling device operates continuously to prevent overheating, then reliability is improved, but losses in the cooling device increase

Engineering Contradiction:
Improvemotor reliabilityVSAvoidcooling device losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system implements feedback control by continuously monitoring temperatures and adjusting cooling operation accordingly. This ensures the cooling device operates only when needed to maintain reliability, avoiding continuous operation and associated unnecessary losses.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system automatically manages cooling device operation based on self-detected temperature conditions. The control unit serves the reliability function by autonomously adjusting cooling rates according to actual thermal states, eliminating the need for continuous high-rate operation.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces total losses in motors, motor control apparatuses, and cooling devices while maintaining temperatures at or below regulated levels, enhancing operational efficiency and longevity.

Implementation Method 1

a coolant supply pipe disposed inside a rotation shaft of the motor along an axial direction, coolant ejection ports that are provided opposite winding edges formed by windings wound around a stator core to eject a coolant from the coolant supply pipe to the winding edges

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a pump for supplying the coolant to the coolant supply pipe, and a pump control means for varying the amount of the coolant discharged from the pump in accordance with a drive state of the motor

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentUS9819300B2Machine learning apparatus for learning operation conditions of cooling device, motor control apparatus and motor control system having the machine learning apparatus, and machine learning method
Publication Date: 2017.11.14 FANUC LTD
  • US9819300B2 patent drawing
  • US9819300B2 patent drawing
  • US9819300B2 patent drawing

AI summary

A machine learning apparatus according to the present invention, which learns the operation conditions of a cooling device for cooling a motor or a motor control apparatus, includes a state observer for observing a state variable including at least one of temperature data of the motor and the motor control apparatus at a specific position during operation of the cooling device; a determination data acquisition unit for acquiring determination data that determines a margin of acceptable value of a loss in each of the motor, the motor control apparatus, and the cooling device and a margin of acceptable value of the temperature of each of the motor and the motor control apparatus at the specific position; and a learner for learning the operation conditions of the cooling device in accordance with a training data set constituted of a combination of the state variable and the determination data.