Fixed-speed partial-load PWM voltage-driven vibroacoustic simulation

In this simulation project tuto_SPMSM_05 at partial load, the voltage is now imposed using an intersective Pulse Width Modulation (PWM) at 1000 Hz.

The following parameters are modified for asynchronous intersective PWM operation:

Input.Simu.type_gensupply = 1;
Input.Simu.type_skin_effect = 1;
Input.Simu.param_PWM{1} =[0 Inf 1 1000];

Four parameters define the PWM to be applied:
- minimum speed: 0
- minimum speed: Inf
- type of strategy: 1 (asynchronous switching)
- switching frequency: 1000 (Hz)

The fourth parameter means that we apply a 1 kHz symmetrical switching frequency independently of the speed (from minimim speed 0 to maximum speed +Inf).

The skin effect is activated in the equivalent circuit with

Input.Simu.type_skin_effect = 1;

If it is not activated a warning message is displayed in the text output.

The PWM generates the following voltage spectrum displayed with plot_voltage_fft: One can notice the harmonics around the multiples of the switching frequency.

PWM voltage spectrum
PWM voltage spectrum

The corresponding phase currents are given plot_currents:

Phase current waveforms
Phase current waveforms

The electro-vibro-acoustic simulation time is still very fast (a few seconds) although higher time harmonics up to 6.2 kHz are included.

Due to PWM operation the acoustic noise spectrum is now enriched with 0 and 2p=4 wavenumbers as seen with plot_ASWL_modal_cont:

0 and 2p=4 wavenumbers modal contributions
0 and 2p=4 wavenumbers modal contributions
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