Sinewave Commutation Reduces Torque Ripple in Permanent Magnet Motors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing HVAC systems employing variable speed motors with square wave commutation techniques experience high cogging torque, operating torque ripple, and efficiency losses, leading to undesirable acoustic noise and vibration due to discontinuous phase currents.

Innovation Solution

Implementing a permanent magnet motor with a motor controller configured for sinewave commutation to produce continuous phase currents, reducing torque ripple and improving efficiency by energizing all three phase windings simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If square wave commutation is used to control variable speed motors, then the motor can operate at variable speeds, but high cogging torque and torque ripple are produced resulting in acoustic noise and vibration

Engineering Contradiction:

Improvevariable speed operationVSAvoidacoustic noise and vibration

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the waveform parameter from square wave to sinewave commutation. This parameter change transforms the discontinuous phase currents into continuous sinusoidal currents, eliminating the abrupt switching that causes cogging torque and torque ripple, thereby reducing acoustic noise and vibration while maintaining variable speed capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical damping materials that were previously needed to reduce noise and vibration with an electrical solution (sinewave commutation). By substituting the commutation waveform, the system achieves noise reduction without requiring additional mechanical damping components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If square wave commutation is used in variable speed motors, then speed control is achieved, but efficiency loss occurs on the order of about two percent

Engineering Contradiction:

Improvespeed controlVSAvoidmotor efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent changes the commutation waveform parameter from square wave to sinewave, which eliminates the discontinuous current periods where no voltage is applied to any phase winding. This continuous current flow improves motor efficiency by eliminating the energy losses associated with abrupt switching and unenergized phases

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If mechanical damping materials are used to reduce noise and vibration, then acoustic noise is reduced, but device complexity and cost increase

Engineering Contradiction:

Improveacoustic noiseVSAvoidmotor structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces mechanical damping materials with an electrical control solution (sinewave commutation). By changing the commutation waveform to produce continuous sinusoidal currents, the system reduces cogging torque and torque ripple at the source, eliminating the need for additional mechanical damping components and simplifying the overall motor structure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces acoustic noise and vibration, enhances motor efficiency, and eliminates the need for mechanical damping materials, resulting in a more cost-effective and quieter HVAC system operation.

Implementation Method 1

a permanent magnet motor having a stationary assembly, a rotatable assembly in magnetic coupling relation to the stationary assembly, and a shaft coupled to the air-moving component

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7626349B2Low noise heating, ventilating and/or air conditioning (HVAC) systems

Publication Date: 2009.12.01 NIDEC MOTOR CORP

AI summary

A heating, ventilating and/or air conditioning (HVAC) system includes a system controller, a motor controller, an air-moving component, and a permanent magnet motor having a stationary assembly, a rotatable assembly in magnetic coupling relation to the stationary assembly, and a shaft coupled to the air-moving component. The motor controller is configured for performing sinewave commutation in response to one or more control signals received from the system controller to produce continuous phase currents in the permanent magnet motor for driving the air-moving component. By using sinewave commutation (in contrast to square wave commutation), the noise and vibration produced by the HVAC system is markedly reduced.