Polyharmonic Flux Motor Braking via Offset PWM Harmonics

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing motor systems face limitations in controlled deceleration and braking due to the rating of the bus voltage capacitor, which restricts the deceleration rate and can lead to system failure if exceeded.

Innovation Solution

The method involves offsetting PWM carriers and injecting a high-frequency signal into the motor control signal to increase motor harmonics, thereby increasing energy losses and enabling higher deceleration rates without exceeding the bus voltage capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If PWM carriers are offset to increase motor harmonics, then motor braking torque is improved, but energy losses increase

Engineering Contradiction:

Improvemotor braking torqueVSAvoidenergy losses

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The patent changes the parameters of the PWM carrier signals by introducing intentional offsets in the carrier frequencies. This parameter modification creates additional harmonic components in the motor current, which increase the braking torque through enhanced magnetic field interactions, while the increased energy losses are acceptable as they facilitate faster deceleration

Inventive Principle:

Principle #35Parameter changes

2Productivity

If deceleration rate is increased, then productivity is improved, but bus voltage capacitor rating is exceeded

Engineering Contradiction:

Improvedeceleration rateVSAvoidcapacitor overload

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the normally harmful effect of motor co-energy during deceleration into a beneficial braking force. By offsetting the PWM carriers, the system generates additional harmonics that increase motor losses and convert kinetic energy into heat more efficiently, enabling faster deceleration without exceeding capacitor voltage limits

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 allows for increased motor braking torque within the limited bus voltage, enhancing deceleration capabilities while preventing capacitor overload.

Implementation Method 1

The method offsets pulse width modulation (PWM) carriers to a motor to increase motor harmonics

Methodology Applied

Scientific EffectPWM (Pulse Width Modulation):

Implementation Method 2

The offset PWM carriers increase energy losses for the motor

Methodology Applied

Scientific EffectHarmonic generation:

Implementation Method 3

The offset PWM carriers increase energy losses for the motor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11901855B2Polyharmonic flux motor loss increase

Publication Date: 2024.02.13 ROCKWELL AUTOMATION TECH INC

AI summary

For polyharmonic flux motor loss increase, a method offsets pulse width modulation (PWM) carriers to a motor to increase motor harmonics. The offset PWM carriers increase energy losses for the motor.