Controlling systems with motor drives using pulse width modulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing PWM methods in HVAC and refrigeration systems cause significant mechanical vibrations due to resonance frequencies, leading to noise and potential damage, and existing solutions either require manual adjustment or increased material costs for damping.

Innovation Solution

A system that uses a controller to select and operate an electronic power converter with a PWM algorithm that mitigates resonance frequencies by analyzing harmonic signatures and determining optimal PWM algorithms to minimize mechanical vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If PWM is used to supply power efficiently, then power efficiency is improved, but mechanical vibrations increase due to resonance frequencies

Engineering Contradiction:

Improvepower efficiencyVSAvoidmechanical vibrations

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system dynamically selects PWM algorithms based on real-time detection of resonance frequencies. The controller continuously monitors the system state and adjusts the PWM algorithm selection to avoid resonant conditions, making the power supply adaptive rather than static. This resolves the contradiction by allowing efficient PWM operation while dynamically avoiding vibration-causing frequencies.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameters of PWM operation by selecting from multiple PWM algorithms with different harmonic signatures. Each algorithm has distinct frequency characteristics, and the system selects the algorithm whose harmonic content does not coincide with the system's resonance frequencies, thereby maintaining efficiency while avoiding vibrations.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If manual adjustment or damping materials are used to reduce vibrations, then mechanical vibrations are reduced, but device complexity or material costs increase

Engineering Contradiction:

Improvemechanical vibrationsVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system replaces mechanical vibration reduction methods (such as damping materials or mechanical adjustments) with a control-based solution. Instead of physically modifying the system to reduce vibrations, the controller selects PWM algorithms that avoid resonant frequencies, substituting mechanical approaches with electronic control intelligence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-diagnosis and self-adjustment by automatically detecting resonance frequencies and selecting appropriate PWM algorithms without external intervention. The controller monitors system responses and autonomously adjusts PWM parameters, eliminating the need for manual adjustment or additional damping components.

Inventive Principle:

Principle #25Self-service

3Device complexity

If a fixed PWM algorithm is used, then device complexity is reduced, but adaptability to different resonance conditions decreases

Engineering Contradiction:

Improvecontrol algorithm complexityVSAvoidadaptability to resonance conditions

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control system transitions from static to dynamic operation by continuously monitoring system resonance characteristics and adjusting PWM algorithm selection accordingly. The controller adapts to changing operating conditions and resonance frequencies, maintaining optimal performance across different system states without requiring complex manual reconfiguration.

Inventive Principle:

Principle #15Dynamics

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

The solution effectively reduces mechanical vibrations by selecting a PWM algorithm that avoids resonance frequencies, thereby reducing noise and potential damage, and allows for dynamic adjustment during the system's life cycle, improving operational efficiency and reducing material costs.

Implementation Method 1

Digital power supplies provide efficient power supply by using pulse-width modulation (PWM) to quickly switch on and off power

Methodology Applied

Scientific EffectPulse width modulation:

Implementation Method 2

determines one or more resonance frequencies associated with the HVAC and/or refrigeration system. The controller also selects a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the one or more resonance frequencies

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS12000638B2Controlling systems with motor drives using pulse width modulation

Publication Date: 2024.06.04 LENNOX IND INC

AI summary

A system includes an electronic power converter and a controller. The electronic power converter supplies power to one or more motor drives of an HVAC system. The controller obtains a plurality of pulse width modulation (PWM) algorithms. Each PWM algorithm has an associated spectrum of frequencies. The controller further determines one or more resonance frequencies associated with the HVAC system. The controller also selects a first PWM algorithm from the plurality of PWM algorithms wherein the spectrum of frequencies of the first PWM algorithm lacks frequency peaks that overlap with the one or more resonance frequencies associated with the HVAC system. The controller further operates the electronic power converter according to the first PWM algorithm.