Full Bridge and Voltage Comparision

M

melissa walraven

Guest
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
 
melissa walraven wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.

I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Click to expand...
Could you just wire the rectifier outputs in parallel, and not worry
about it?

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
 
melissa walraven wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Click to expand...
For sensing the current through each bridge for
comparison, I would delete D1 and D2, then place current -
sense resistors in series with the ground connection
to each bridge.

--Winston
 
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
<walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Click to expand...
---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.



--
JF
 
John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa

---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.
Click to expand...
How would you compare the current from each bridge?

--Winston
 
On 4/24/2012 1:44 PM, melissa walraven wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Homework?
Click to expand...
 
On Tue, 24 Apr 2012 15:32:12 -0400, Tom Biasi <tombiasi@optonline.net>
wrote:

On 4/24/2012 1:44 PM, melissa walraven wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Homework?
Click to expand...
Looks like it. Not enough detail if it were a _real_ two source
situation.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On 4/24/2012 3:37 PM, melissa walraven wrote:
not a homework at all

Melissa

Could you tell us why you need to know this information?
Click to expand...
 
On Tue, 24 Apr 2012 15:45:57 -0400, Tom Biasi <tombiasi@optonline.net>
wrote:

On 4/24/2012 3:37 PM, melissa walraven wrote:
not a homework at all

Melissa

Could you tell us why you need to know this information?
Click to expand...
Please. Like what is the application?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
melissa walraven wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?
Click to expand...
As others have said, you can get rid of D1 and D2. Their function is
already being provided by the right two diodes in each rectifiers.

Now, instead of connecting the anodes in the rectifiers directly to
ground place a shunt resistor into those connections. Both of them.
Calculate the resistor so that at nominal load you get a voltage drop
you can easily measure. If you use a comparator such as the LM339 then
50-100mV would suffice. Rate these shunt resistors accordingly for power.

Now you can compare the two and find out which source contributes more.
You could also use meters or AD converters to find out the ratio. When
the sources are within about a volt of each other then both will
contribute some.

Remember that the signal on that shunt will pulsate at twice the input
frequency.

--
Regards, Joerg

http://www.analogconsultants.com/
 
"melissa walraven" <walravenmelissa@gmail.com> wrote in message
news:718275f3-3562-4fdf-b37b-7faced64b819@a5g2000vbl.googlegroups.com...
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Click to expand...
If the 2 bridge outputs are reasonably similar, the simplest way is load
each in turn with a resistor and measure the resistor's temperature rise -
DMMs with K-type thermocouples are quite reasonable these days.

80kHz is quite fast, so you want Shottky-barrier or silicon carbide
rectifiers or their dissipation will be as high as the resistor.
 
On Tue, 24 Apr 2012 11:29:47 -0700, Winston <Winston@Bigbrother.net>
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa

---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.

How would you compare the current from each bridge?

--Winston
Click to expand...
---
Who cares?

All she wants is to have the bridge with the highest output voltage
drive the load.

--
JF
 
John Fields wrote:
On Tue, 24 Apr 2012 11:29:47 -0700, Winston<Winston@Bigbrother.net
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa

---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.

How would you compare the current from each bridge?

--Winston

---
Who cares?
Click to expand...
Melissa the OP, yes? (Emphasis mine):

"I am trying to *compare the magnitude of the DC outputs* of two full
bridge rectifiers."

"Based on the magnitude of the DC output, *I have to decide
which bridge will be providing power* to the load as shown in the
link."

"I posted the circuit at the following link *to compare the two output
voltages*"

All she wants is to have the bridge with the highest output voltage
drive the load.
Click to expand...
I didn't get that from her post. :)

--Winston
 
John Fields wrote:
On Tue, 24 Apr 2012 11:29:47 -0700, Winston <Winston@Bigbrother.net
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.
How would you compare the current from each bridge?

--Winston

---
Who cares?

All she wants is to have the bridge with the highest output voltage
drive the load.
Click to expand...
AFAIU Melissa wants to know which bridge is currently driving the load.
If that is so then she needs a signal that tells her.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On 2012-04-24, melissa walraven <walravenmelissa@gmail.com> wrote:
Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?
Click to expand...
It depends how the AC sources are correlated with one another and with
the circuit ground, it also makes the assumption that you want to drw
power from the source with the greatest amplitude.

also D1 and D2 serve no purpose, as they only duplicate the
functionality of the diodes on the right half of the two bridges.
the could be omitted (replaced with wire)

--
⚂⚃ 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---
 
On Tue, 24 Apr 2012 14:47:57 -0700, Winston <Winston@Bigbrother.net>
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 11:29:47 -0700, Winston<Winston@Bigbrother.net
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa

---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.

How would you compare the current from each bridge?

--Winston

---
Who cares?

Melissa the OP, yes? (Emphasis mine):

"I am trying to *compare the magnitude of the DC outputs* of two full
bridge rectifiers."

"Based on the magnitude of the DC output, *I have to decide
which bridge will be providing power* to the load as shown in the
link."

"I posted the circuit at the following link *to compare the two output
voltages*"

All she wants is to have the bridge with the highest output voltage
drive the load.

I didn't get that from her post. :)

--Winston
Click to expand...
---
Oh, well...

--
JF
 
On Tue, 24 Apr 2012 14:48:44 -0700, Joerg <invalid@invalid.invalid>
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 11:29:47 -0700, Winston <Winston@Bigbrother.net
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.
How would you compare the current from each bridge?

--Winston

---
Who cares?

All she wants is to have the bridge with the highest output voltage
drive the load.


AFAIU Melissa wants to know which bridge is currently driving the load.
If that is so then she needs a signal that tells her.
Click to expand...
---
Fair enough.

Maybe she'll tell us what she wants.

--
JF
 
On Tue, 24 Apr 2012 17:57:59 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 24 Apr 2012 14:48:44 -0700, Joerg <invalid@invalid.invalid
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 11:29:47 -0700, Winston <Winston@Bigbrother.net
wrote:

John Fields wrote:
On Tue, 24 Apr 2012 10:44:11 -0700 (PDT), melissa walraven
walravenmelissa@gmail.com> wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
---
If you remove D1 and D2 and connect the outputs of the two bridges
together, then when the output voltage of the upper bridge is higher
than the output voltage of the lower bridge, current out of the bottom
bridge will be blocked and the load will be fed by the upper bridge.

Conversely, if the output voltage of the lower bridge is higher than
that of the upper bridge, the upper bridge will be cut off by the
lower bridge and the load will get its current from the lower bridge.

Plus, you won't have to suffer the losses in D1 and D2.
How would you compare the current from each bridge?

--Winston

---
Who cares?

All she wants is to have the bridge with the highest output voltage
drive the load.


AFAIU Melissa wants to know which bridge is currently driving the load.
If that is so then she needs a signal that tells her.

---
Fair enough.

Maybe she'll tell us what she wants.
Click to expand...
Unless someone else does her homework for her ;-)

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
melissa walraven wrote:

Hi,

I am trying to compare the magnitude of the DC outputs of two full
bridge rectifiers.

The two rectifiers are getting inputs from two different sinusoidal
sources of frequency 80 KHz who are in phase but could have different
amplitudes. Based on the magnitude of the DC output, I have to decide
which bridge will be providing power to the load as shown in the
link.


I posted the circuit at the following link to compare the two output
voltages

http://img542.imageshack.us/img542/655/file2d.jpg

Am I on the right thinking process?

Melissa
Click to expand...
How much of a voltage difference of detection are you looking for?

Jamie
 
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