Timeline for Design of variable split rail power supply
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 28, 2016 at 16:57 | comment | added | Andy aka | I don't see that being a problem. | |
| May 28, 2016 at 16:53 | comment | added | Cotlone | @Andyaka Thanks for your reply and sorry about my delay! Ok, I'm not sure whether that happens either, I actually thought it was a linear effect due to the electric field. But I think that running a unipolar configuration will not be an issue unless I get into non-linear response regions of the piezo (which I'm not likely to). As a related point, do you think there are any issues in having a common ground across all of these bridges which will be running out of phase (independently)? | |
| May 20, 2016 at 8:19 | comment | added | Andy aka | If you are using a basic piezo device then it has series capacitance and this will do exactly the same as an external capacitor. So, with a series of unipolar pulses there will be a an average dc offset across that capacitor, yes. Will it affect what you want to do - it might if you have a piezo transducer that elongates an amount and stays elongated while DC is applied. I'm not sure that this happens in a piezo - isn't movement due to the differential of voltage applied i.e. if you compressed a piezo it would generate volts but then that voltage would fall to zero. | |
| May 19, 2016 at 23:48 | comment | added | Cotlone | Forgive me if I'm wrong here, but does not a series capacitor prevent transmission of DC component by essentially, causing zero net charge transfer between point and negative swings, such as that seen is this image: dnp.fmph.uniba.sk/~kollar/je_w/image464.gif If this is correct, a sequence of unipolar pulses has a DC base line component that would depend on duty factor. I imagine that, with reference to an unbiased piezo device, the amount of strain induced in either direction would be effected by the applied voltage in that direction. | |
| May 18, 2016 at 7:15 | comment | added | Andy aka | I'm unsure what you mean by a baseline shift and unbalanced voltage swing. | |
| May 17, 2016 at 21:48 | comment | added | Cotlone | @Andyaka I appreciate the DC filtration of the load, thanks for the explanation. I just had a thought though, if I use a PWM signal to modulate power to the transducers, is this likely to cause a baseline shift resulting in an unbalanced voltage swing? Am I right in thinking that regardless of whether I use bipolar power rails, this effect would still occur? | |
| May 17, 2016 at 21:37 | vote | accept | Cotlone | ||
| May 13, 2016 at 20:37 | comment | added | Cotlone | @GeorgeHerold thanks for the link. At this stage though, we probably aren't looking at polarised actuators. The piezos will be used for US generation. | |
| May 13, 2016 at 17:48 | comment | added | Andy aka | @GeorgeHerold if the OP is using a polarized one then taking the voltage too negative could be very problematic! | |
| May 13, 2016 at 17:35 | comment | added | George Herold | @Cotlone, I should add that these piezo actuators are polarized... they do not like too big a reverse voltage. | |
| May 13, 2016 at 17:33 | comment | added | George Herold | @Andyaka thorlabs.de/newgrouppage9.cfm?objectgroup_id=8040 thorlabs.de/newgrouppage9.cfm?objectgroup_id=61 Well here are a few, we use something like the second link, but buy from a distributor (not Thor labs.) These are ~100V and move a few microns. I can look up the part number and distributor if that is what you might be looking for, | |
| May 13, 2016 at 16:56 | comment | added | Cotlone | Thanks for the replies gentlemen. Due to my application, I'm interested in the dilatation part of the waveform, which is why I was considering split rail. I'll look further into using a push-pull design with the series capacitor. | |
| May 13, 2016 at 16:32 | comment | added | Andy aka | @GeorgeHerold do you have a link - it would be useful to me. | |
| May 13, 2016 at 16:29 | comment | added | George Herold | I'm not sure the "flavor" of the OP's piezo, but I use some that are DC devices. (position control) | |
| May 13, 2016 at 16:22 | history | answered | Andy aka | CC BY-SA 3.0 |
