Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: legg Newsgroups: sci.electronics.design Subject: Re: power supply discharge Date: Sun, 29 Sep 2024 09:14:42 -0400 Organization: A noiseless patient Spider Lines: 54 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Injection-Date: Sun, 29 Sep 2024 15:12:40 +0200 (CEST) Injection-Info: dont-email.me; posting-host="d77ba8463aa907909edce00af8bdcea4"; logging-data="1861152"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1956U3sJkNhDl9J2MSp8o9L" Cancel-Lock: sha1:Tnze934KHArybQUAqIZ1IytKll0= X-Newsreader: Forte Agent 4.2/32.1118 Bytes: 2888 On Sat, 28 Sep 2024 11:56:52 -0700, KevinJ93 wrote: >On 9/28/24 6:44 AM, legg wrote: >> On Fri, 27 Sep 2024 08:07:29 -0700, john larkin wrote: >> >>> >>> Given a benchtop power supply, you can turn the voltage up and then >>> down, and it goes down. Most have a substantial amount of output >>> capacitance, and can be driving an external cap too. So something >>> pulls the output down. >>> >>> I guess that there are no standards for this, but I've never seen a >>> supply that just hangs high when it's cranked down. >>> >>> I'm designing some programmable multi-channel power suplies and that >>> is one of many tangled issues in the project. >> >> Twiddling the adjustment knob on a bench supply doesn't >> represent a dramatic change - and most adjustible >> supplies don't load their output terminals with a >> lot of capacitance. >> >> DC coupled programable supplies, or bipolar programmable >> supplies are made to drive loads in the first and third >> quadrants. >> >> There are issues in the second and fourth quadrants, where >> the supply is expected to absorb power. >> >> An amplifier driving a pure reactance experiences the same >> losses as driving a dead short. >> >> RL > >Some specialist power supplies for large scale battery testing can >absorb power and return it to the AC supply. > >https://eepower.com/tech-insights/regenerative-power-supplies-create-lots-of-energy-at-electronica/# > >kw It's always made more sense in power test gear, if you can afford it. It's a penny-pinching part of the industry. In the loading case, you don't end up contributing much to the line, you just draw net losses from processing, so no complications for hydro. For PV or other energy sources - it's a negotiation that's dependent on local supplier and contracted regs. RL