Bombardier IGBT VVVF | Class 387/1 Traction Sound | PWM Inverter - Class 387 Inductor Recording

Class 357/375/377/379/387 traction inverters - the Electrostar sound when running on 25kVAC and not the 750VDC power mode: • Bombardier IGBT VVVF |...
Listen closely and see the three-level PWM patterns from the Mitrac DR1000 Train Control & Management System (TCMS used as a TCU) which run the Class 387 traction motors.
Mistake: where it says 6P while braking, this is supposed to say MP.
I've looked at the patterns briefly, thanks to the community we can see:
MP Async, 15P Sync, 6P Sync, 5P Sync, 3P Sync, 1P Sync.
Bombardier Transportation UK Ltd, the previous developer of the Electrostar platform, is now owned by Alstom Engineering and Services Ltd.
Noise reduction post-processing:
44100Hz sample of the ACU, HVAC, and Transformer
48dB reduction
Triple sensitivity with no smoothing
Filter:
50Hz band
102dB reduction
Equipment used:
2x 1000mH telephone pickup coil
Sony ICD-PX470
Class 357 Traction Motor Sound
Class 375 Traction Motor Sound
Class 377 Traction Motor Sound
Class 379 Traction Motor Sound
Class 387 Traction Motor Sound
#induction #inductorwindingmachine #motor #vvvfサウンド #vvvfインバータ #vvvf #train

[@louscr8249]

Nice video would be interesting also to do a recording of the 395 on both AC and DC modes 😮

[@bb-3653]

Ah you are the first to have the electrostars induction recording. Really cool! Also werent the second gen electrostars developed slightly beyond the original system? But i guess they are largely controlled the exact same.

[@ItsYa165]

Funny enough, all Electrostars are DR1000, the Movia is DR1000, so basically the only difference in modulation is based on voltage amplitude which makes sense. The pulse modes will differ like this because different amplitude means comparing two different things. If you supplied the 2009 stock with 25kV and a transformer, it would sound like the 387 on 25kV. If you supplied it with 750VDC by the ACU, the 2009 stock would sound like a 375 or 376. The only difference is the transmission and the model of mo'or. It's quite interesting how voltage affects VF performance.

[@bb-3653]

@@ItsYa165 makes sense. The 09 transmission sounds are almost Inaudible. So it sounds dead after a while. It would be cool to see a modern train use a gear ratio that matches sync mode , The closest is 745s with their transmission sound , but the pitch is slightly higher relitive the the motors spin so its not exactlythe same as a sync mode sound. (Typically syn mode noise are in tandom with a mildly audiable hum sounds in the exact same way, whether its on an electrostars sync mode or a class 385 sync mode eventually they all rise in pitch the same relative to motors RPM)

[@ItsYa165]

@@bb-3653 I think you're not understanding what sync is. Sync, synchronous modulation, is where the pulse count is a fixed number but variable width and voltage amplitude. With that constraint, it means the frequency of the entire bridge's operation must match the fundamental electrical frequency to maintain that pulse count. Inherently, every gearbox is synchronous. How can you have an asynchronous gearbox? Do cogs change the number of teeth over time? Obviously not. The gearbox is literally fastened to the motor's drive shaft and the shaft frequency is directly proportional to the electrical frequency. Let's also get rid of terms like "pitch", and "hum" and start using terms like frequency, power, fundamental, pulse... etc. Different induction motors will be fed different asynchronous and synchronous patterns and power based on their ratings as provided by the manufacture. Controlling it requires programmed logic: current controllers, position sensors, current sensors are examples of the technology used to parametise this program. With this, you can estimate the speed and position of the rotor which is great for knowing the electrical frequency and therefore the mechanical (rotor) frequency... but it's not enough to make informed decision on how many pulses should be generated. This logic is determined by things like the size and shape of the flux locus (whether that's a 2D hexagon around the stator, or 3D) which indicates the effective flux trajectory from line-to-line, or the modulation index (the ratio of the carrier voltage on one half of the bridge to the line voltage) with respect to frequency - indicative of the amount of flux but not its path. This is what trains like Bombardier's Electrostars and Talents do, the latter for determining pulse modes. Why is this important? The whole reason for using synchronous modulation is to reduce the amount of current harmonics generated and to prevent the carrier sidebands from spreading to occupied frequencies. The speed of the train can't be used directly because rotary encoders mechanically impede the drive shaft. So the TCU has to calculate when to sync the inverter, and what speed. On a train-by-train basis, this is obviously going to occur at different speeds because what does speed itself have to do with anything? That results in clocking sync modes at higher or lower fundamental frequencies. The speed of the gears will not instantaneously change because of what you do with the inverter... the same goes for the rotor frequency... the same goes for the fundamental electrical frequency - they're all proportional to each and never become disproportionate otherwise something broke.

[@CR400AF-B]

The first sync pwm is 15-pulse

[@ItsYa165]

Thank you so much 😸 I can see how it can be 15P, but was uncertain.

[@Delta1Productions]

Could you try this with the new class 777s? They seem to have an interesting motor pattern when decelerating compared to accelerating and I’d like to see how the waveforms are so I could recreate them in a simulator

[@ItsYa165]

Maybe in the future

[@Pablo-Iza]

how did you make this?

[@ItsYa165]

It's an electromagnetic recording