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Seminar | Acoustics of Electric Drives

Innovations in electric drive technology and improved storage technologies are currently strong drivers in the field of electromobility. In the industry, topics such as noise generation and sound radiation are becoming increasingly important throughout the entire development process. When designing electric drives, on the one hand normative specifications must be addressed in terms of noise generation, and on the other hand properties relating to comfort, performance and brand image are decisive.
In order to be able to design components that fit precisely, OEMs and suppliers are required to understand and master the acoustic phenomena that occur in electric drives. In the 'Acoustics of Electric Drives' training, we provide you with a broad, interdisciplinary knowledge of all aspects of the acoustics of electric drives and introduce various solution approaches for addressing acoustic phenomena.



The modular concept provides you with both basic and advanced topics from e-drive technology and acoustics. These include data acquisition and analysis as well as calculation and simulation. In four online events, we work with you to acquire theoretical knowledge from both disciplines. A test bench day at the Fraunhofer-Institute in Dresden offers you the opportunity to combine theory with practice so that you develop skills and methods for test bench application. The consistent reference to an example makes it easier for you to recognize interrelationships and modes of operation.


User and technical project managers who

  • perform validations of e-drive concepts,
  • are responsible for e-machine design,
  • are entrusted with the development of e-drives,
  • are responsible for targeting.



Test bench events live ... Setup - Data acquisition - Evaluation. This and much more is what you can expect in the training.

You are also welcomed to take a first look into the training documents. 



Module 1 Basics of E-Drives

  • Energy conversion, e. g.

           ► 4-quadrant operation

           ► (Energy) efficiency

           ► Space vector theory

           ► Sankey Diagram

  • E-machine types and their mathematical description, especially

           ► Miniature drives

           ► 3-phase induction motor with star and delta connection 

  • Inverter technology, especially

           ► Inverter

           ► Pulsed, pulse width modulated voltage

           ► Commutation types

  • Control engineering, e. g.

           ► Synchronous / Asynchronous machine

           ► d/q current control

           ► Encoder evaluation

           ► Controlled vs. regulated operation

           ► Controller setting criteria

           ► Control characteristics for SM (MTPA) and ASM

           ► Field weakening principle

  • Effective chain overall drive and acoustic force excitation

Module 2 Basics of Acoustics

  • Basic knowledge Acoustics, e. g.

           ► Airborne / Structure-borne sound

           ► Hearing sensation, level calculation, psychoacoustics

           ► Frequency weighting for airborne and structure-borne sound

  • Measurement technology / Sensors, e. g.

           ► Mikrophone, microphone types

           ► Accelerometers

           ► Force transducers

           ► Torque transducers

           ► RPM sensors

  • Sensor positioning, especially

           ► Isolation and connection

           ► Reproducibility

  • Data Acquisition, in particular

           ► Signal conditioning and filtering of raw data

           ► Analog-to-digital conversion

           ► TTL signals, frequency signals

  • Spectral analyses, e. g.

           ► FFT (Narrowband frequency analysis)

           ► Order analysis

           ► N'th Octave analysis (3rd Octaves)

Module 3 FE calculation of the force excitation at the e-drive

  • 2D FEM model of an PMSM

           ► Magnetic field and force waves in the air gap

           ► Air gap flux density, force density

  • 2D Order Analysis

           ► E-motor orders from magnetic circuit geometry

           ► PWM orders from the control

           ► Acoustically relevant force orders

  • Origin of harmonics
  • Transfer to calculation with real current courses
  • Calculation of control and modulation
  • Force excitation by current harmonics
  • Demonstrating calculation possibilities
  • Effective chain of the overall system for acoustic excitation

           ► Current control and modulation by software

           ► Magnetic stator flow

           ► Rotor flow of the permanent magnets

           ► Resulting air gap

           ► Voltage feedback (induction)

           ► Resulting radial and tangential force shaft

  • Test bench concept for blocked forces

           ► Source characterization methods

           ► Ideal and real test candidate mounting

           ► Implementation of the "blocked force" condition on the test bench

  • Load unit design

Module 4 E-Drive specific Acoustics / E-NVH

  • Measurement technology for E-NVH, especially

           ► Sensors for electric and acoustic quantities

           ► Cable shielding concepts

  • Filter, particularly

           ► Frequency and order filter in the time domain

           ► Order extraction

           ► Sound Design

  • PWM fans, e. g.

           ► Offset definition

           ► Order evaluation with inverter frequency offset

           ► Sound Design with frequency offset

  • Animation, e. g.

           ► Impact measurement

           ► Operational Deflection Shape (ODS) analysis

  • Transformations and analyses in the angle domain

           ► Clarke Transformation

           ► Park Transformation

           ► Correlations in the angle domain

  • Valuation, interest methods

           ► Psychoacoustics

           ► Analysis standards airborne noise

           ► Blocked Forces

Module 5 Test Bench Day

A unique opportunity is our test bench day: You spend a day at the component test bench at Fraunhofer IWU in Dresden with measurements on the training motor. 

Through the test bench activities, instrumentation, adjustment, and data acquisition become tangible for you. Applying the measurement technology and the subsequent data check will give you an impression of the dynamic data and their evaluation. You will gain a hearing impression and will be able to qualitatively classify and memorize it by comparing it with various presentations. A comparison of variants allows you to hear the effects of different motor control strategies.

In order to clarify interrelationships, it is important for us to relate the training to an example throughout. Thus, all the theoretical content of the 'advanced topics' relates to the test bench motor and the practical part specifically picks up on the knowledge from the online training in the test bench measurements. You have the opportunity to generate measurement data yourself and to participate in its evaluation.

The small group size offers plenty of room for interaction and reflection. The breaks allow for the opportunity to deepen contacts and exchange experiences. And of course, you can take your data home with you in ATFX format at the end.



21./22.09.2021, 08:30 – 12:30 h   Online Modules 1+2: Basics of E-Drives & Acoustics
27./28.09.2021, 08:30 – 12:30 h   Online Modules 3+4: FE calculation force excitation & E-NVH
05.10.2021, 08:00 – 17:00 h          Practice day at component test bench of the IWU in Dresden


  • Theory: Web-Seminars (Microsoft Teams)
  • Practice: Classroom training in Dresden at the component test bench of the Fraunhofer IWU
    Fraunhofer-Institute for Machine Tools and Forming Technology IWU, Technical Acoustics, Nöthnitzer Strasse 44, 01187 Dresden, Germany

Number of participants

  • Max. 10 persons – in accordance with Corona requirements, currently only 6 persons to ensure the necessary hygiene and social distancing measures


  • 2000.- € excl. VAT per person


The training "Acoustics of Electric Drives" is a joint event of the Fraunhofer-Institute IWU and Müller-BBM VibroAkustik Systeme GmbH.
The terms and conditions published on the registration page apply.

About Fraunhofer IWU

The Fraunhofer-Institute for Machine Tools and Forming Technology IWU is the leading institute for resource-efficient production within the Fraunhofer-Society. Our main focus is on the development of efficiency technologies and intelligent production facilities for the manufacturing of chassis and powertrain components. The trend towards ever lighter and more material-efficient designs has a significant impact on the vibration behavior of a structure. With our experience in the field of technical acoustics and state-of-the-art analysis and measurement methods, we develop innovative solutions for current issues such as electric main and auxiliary drives.

About Müller-BBM VibroAkustik Systeme  

Müller-BBM VibroAkustik Systeme is one of the global market leaders for pathbreaking, integrated solutions for the acquisition, analysis, and management of physical data in the fields of acoustics, vibration, and strength. Our PAK software is used across the industry, especially in fields of automotive, aerospace, and mechanical engineering. PAK is the choice in a wide range of applications - whether NVH, vibro-acoustic engineering, troubleshooting, quality assurance, research, and development. This also includes innovative metrological solutions with regard to acoustics and vibrations of electric drives.