HPSDR DEMETER

项目负责人：Jeroen, PE1RGE

"Demeter" 是 HPSDR 电源项目的名称。尽管电源可以被广泛的使用，但 Demeter 是专为 HPSDR 项目设计的。

在 2008 年 6 月 13 日，Tiny Demeter 被添加到 Demeter 页面中。Tiny Demeter 的设计思想十分简单。它更适合实验的目的，使得动手构建 Demeter 之前可以培养一些经验。

更多的资料将会呈现在该页面之上。

73 Jeroen PE1RGE

下面是一些 HPSDR 邮件列表的讨论结果 ( 2007 年 6 月 11 日 ):

DEMETER 性能指标

输入 - Input

13.8 Volt DC (always 13.8 V or is there a supply range, see remark below)
110 Vac (mains)
230 Vac (mains)
Battery (13.8 Volt) input with automatic switchover
输入接插件 - Input connector
Powerpole connector for DC 13.8 Volt
Mains connector: National standard

输出电压 - Output voltages

Remote switchable voltages
+5 Volt @ …. Amps
+12 Volt @ ….. Amps
-12 Volt @ ….. Amps

待机供电 - Standby supply (for GPS-engine and OCXO)

Constant on
+5 Volt
+15 Volt
+24 Volt (depends on OCXO used, if possible user definable/adjustable)

输出接插件 - Output connector

ATX-connector
DIN 41612 (Atlas connectors)

保护 - Protection

Input protection (high/low voltage, polarity)
Output protection (current limiting, voltage crowbar)

检测 - Monitoring

Input voltage
Output voltage Output currents
Temperature

电源供给通信 - Power supply communication

Atlas backplane
USB-bus
1 wire interface (controlled by a board on Atlas)
Dumb-interface using the pins T7 and T8 on the Atlas

同 HPSDR 的连接 - Connection to the HPSDR

Using the ATX power connector, communication via the USB bus
Using the DIN41612 connector using the Atlas backplane for communication

Position of the power supply

On the Atlas backplane
In a separate box (outside/inside Pandora)

HPSDR configuration

Ozymandias - interface module
Mercury – receiver (5V @ 500mA, 12V @ 200mA, -12V not used)
Penelope – transmitter (5V @ 300mA, 12V @ 200mA, -12V not used))
Alexiares - RF Bandpass Filters
Gibraltar - frequency standard
Epimetheus - antenna and other switching
Measured: Ozy + Janus: +12v @ 200mA, +5v @ 180 ma, -12v @ 70 ma

Questions/remarks

Switching or Linear?
Internal/External?
Power dissipation (Convection cooling/ forced air-cooling)?
Do we need computer monitoring of voltages and currents?
Include an USB-HUB (use one of the ports for the power supply communication)?
Configuration (to use or not to use the SDR-1000)? People who use it in combination with the SDR-1000 need less power from the power-supply and are using a custom built supply or the SDR-1000 power supply.
Will the 13.8Volt really be 13.8Volt or “something” between 11.0 Volt and 15 Volt? In other words: How many people are going to use the HPSDR mobile?
Linear (A “lot of heat”, not “green”, easy to construct and trouble-shoot)
Switching (Less heat, more “green”, more noise, more difficult to construct)
Transformers: From my opinion there will always be a normal mains-transformer, both in the switching and the linear power supply option. Building a switcher for 110Vac/230Vac is too dangerous and complicated (safety regulations) for (less experienced) home-builders. The switcher will be situated in the low-voltage part.

Tiny Demeter

Based on the Teamspeak Session from 31st of May 2008 the idea arose to develop a simpler power supply. The working title for this supply became Tiny Demeter.

This supply could be handy for: - experimenters - people who want a simple configuration - temporary solution unitl Demeter becomes available

Tiny Demeter uses the station power supply as main-source. It expects a fairly well regulated 13.6 till 13.8Volts. From this voltage it will generate:

  • +12V @ 1Amp
  • +5V @ 1.5Amp
  • -12V @ -0.3Amp

Current rating can be increased by adding multiple regulating power transistors.

The regulators for Tiny Demeter (and Demeter) will be build from discrete components. The reason for this are the following:

  • It allows "current scaling", by adding more power transistors the current handling can be increased
  • A discrete regulator gives better temperature stability
  • A discrete regulator gives lower output-noise

From the basic idea of having just a few linear regulators the following extras were added:

  • Input voltage monitor; This will warn the user when the input power source voltage is too low. (If the input voltage is below a certain threshold the +12V stability cannot be guaranteed, probably causing problems in the HPSDR system.)
  • Temperature regulator/monitor; Due to the nature of linear regulators the power dissipation will be around 15 Watts (without extra regulating transistors).
  • Crow-bars for each supply voltage; For added safety
  • Shunt-resistors to measure the current for each supply-voltage
  • Input protection circuit; probably consists of a fuse and a diode OR a fuse and an electronic switch (switch only closes when the input voltage has the right polarity).
The board itself will have a:
  • An ATX 20pin power connector attached to its PCB, so it plugs in directly on Atlas
OR
  • An ATX 20pin power connector attached to a short cable and mounting brackets which can be used to mount Tiny Demeter on the mounting holes of Atlas

The proposed schematic block-diagram can be found below:

Design Ideas

Here some references are made to components and ideas which I have in mind for the Tiny Demeter design:

Transformers for the switcher:

  • www.bourns.com/pdfs/pm600_610_620_series.pdf
  • www.cooperbussmann.com/3/CoiltronicsFinder.html

Linear regulator

  • discrete: see schematic
  • Linear Technology LT3080

Crow Bar

The principle of the regulator with the discrete components:

Media:Regulator.pdf

The best topology for the switcher has to be determined. At this moment a Push-Pull configuration looks very promising. This will generate the least harmonics as the duty-cycle of the switcher is close to 50%. To get an idea of a push pull switcher one can look here: http://sound.westhost.com/project89.htm

Please note: THIS IS NOT THE DESIGN FOR DEMETER, ONLY AN EXAMPLE OF THE TOPOLOGY.

Preliminary design

The following documents contain a part of the design of Tiny Demeter. "Tiny Demeter design.pdf" contains (some) engineering notes. The file "Schematic Prints.pdf" contains the schematic of the switcher, however without the correct values for the components. You can use it to get a general idea of the DC/DC converter design. More details of the design will be added soon!

Design notes: Media:Tiny_Demeter_design.pdf

Preliminary (partial) design: Media:Schematic_Prints.pdf

--PE1RGE 08:36, 1st August 2008 (PDT)

HPSDR 其它模块







注：Demeter（原文出处，以上翻译整理仅供参考!）