# How to run acoustic noise maps calculations?

### Principle

For variable speed applications, especially for automotive applications such as Hybrid Electric Vehicles and Full Electric Vehicles, it is convenient to calculate the NVH behaviour of the electric powertrain in the torque/speed plane. This way, the acoustic noise / vibration / harmonic forces at any operating point can be obtained and the noise can even be synthesized along a driving cycle. Besides the NVH difference between braking and traction can also be observed.

Building acoustic noise maps requires to specify the current angle as a function of speed for each torque level, which depends on the chosen control strategy (e.g. MTPA). Two definitions are possible:

1. define the matrices T(N,I) and T(N,Phi0) (torque level T function of phase current level I, speed N and current angle Phi0) , Id & Iq currents function of torque level and speed - see the templace of Excel sheet in Test/Validation_data/InputNoiseMapTemplate.xlsx
2. define the matrices Id(T,N) and Iq(T,N) (Id & Iq currents function of torque level T and speed N) - see the templace of Excel sheet in Test/Validation_data/InputNoiseMapTemplate2.xlsx

In these matrices unknown values can be left empty.

### Scripting implementation

To activate the calculation of the acoustic noise map one must choose respectively for input type 1 and 2

`Input.Simu.type_noise_map=1;`
`Input.Simu.type_noise_map=2;`

The noise map is automatically run at the end of the fixed speed simulation. To display the acoustic noise map one can type the following plot commands:

`plot_VS_ASWL_map`

It gives the following type of graph:

Noise map of a 48s8p IPMSM traction machine

For further details see the dedicated page on plot_VS_ASWL_map plot command.

TBC