I'm trying to get a 350V DC output from a 24V supply,but my output doesnt go higher than 24V. Could someone explain where im going wrong. This is the first time im doing something like this.

 

I'm trying to get a 350V DC output from a 24V supply,

Hi dee,
You say you want a 350Vdc output when using a 5R Load, that is 70 Amps.
For a 24Vdc source voltage, at 100% conversion efficiency gives a ratio of 14.5, so the 24V source would have to supply 70A * 14.5 = 1015 Amps.

Recheck your actual circuit requirements.
E

 

Do your simulation with R1=1kOhm, then you will understand what ericgibbs means

 

Hi dee,
You say you want a 350Vdc output when using a 5R Load, that is 70 Amps.
For a 24Vdc source voltage, at 100% conversion efficiency gives a ratio of 14.5, so the 24V source would have to supply 70A * 14.5 = 1015 Amps.

Recheck your actual circuit requirements.
E

I'm actually trying to design the High voltage DC bus for a pure sine wave inverter, if that makes this any clearer. So this will provide the power rail to the H-bridge for my sine wave inverter. What should I consider when designing this stage? Thank you for the reply.

 

I'm actually trying to design the High voltage DC bus for a pure sine wave inverter, What should I consider when designing this stage?

hi dee,
You need to specify the required load voltage and current for the project.

Why is it required to be a 'pure sine wave' for a 350Vdc load???

Please post the final full specification.
E

 

hi dee,
You need to specify the required load voltage and current for the project.

Why is it required to be a 'pure sine wave' for a 350Vdc load???

Please post the final full specification.
E

Hi ericgibbs,
I need the 350V to reconstruct a 50Hz 230V rms sine wave using SPWM, im using an eg8010 to generate the spwm.

 

Hi ericgibbs,
I need the 350V to reconstruct a 50Hz 230V rms sine wave using SPWM, im using an eg8010 to generate the spwm.
As part of our project we are building a pure sine wave inverter.

Like so, but our input voltage is 24V and output power is 300W

 

Like so, but our input voltage is 24V and power is 300W

hi dee,

What is the current load on the 350Vdc output?

E

 

Like so, but our input voltage is 24V and power is 300W

What is the current load on the 350Vdc output?

Probably the output power is about 300W. 350V at 300W is 0.857A. The load will look like 408 ohms. (not 5 ohms)

 

And even then the TS will not get an output voltage of 350 V as long as he uses diodes with a breakdown voltage of 150 V.

 

I'm actually trying to design the High voltage DC bus for a pure sine wave inverter, if that makes this any clearer. So this will provide the power rail to the H-bridge for my sine wave inverter.

Hi.
I read this TS's quote as he is expecting to 'provide the power rail to the H-bridge'.
This is why I keep asking him for details regarding the current he is requiring to drive this bridge load.
As he has a 5R load on his LTSpice circuit suggests he may think he has designed a power amplifier circuit.!??

E

 

hi dee,

What is the current load on the 350Vdc output?

E

Sorry for not replying sooner, I need to build it for a maximum load current of 1.3A

 

Hello,

When the input is 300 Watt, you can not get 455 Watt (350 Volt × 1.3 Amp) on the output.
You likely should have 500 Watt or more on the input, depending on the efficiency.

Bertus

 

Like so, but our input voltage is 24V and power is 300W

I need to build it for a maximum load current of 1.3A

Then there is loss in the H bridge.
Your batteries can only supply 300W and you want 500W (output power + loss) you need to think about power. Things are not adding up.
Maybe you are thinking 1.3A peak and 0.8A average.

 

Then there is loss in the H bridge.
Your batteries can only supply 300W and you want 500W (output power + loss) you need to think about power. Things are not adding up.
Maybe you are thinking 1.3A peak and 0.8A average.

Sorry, I meant my output power should be 300W.

 

Sorry, I meant my output power should be 300W. Output RMS current is 1.3A

 

I'm designing a push pull converter to convert 24V to 350V DC. This is to be used for a pure sine wave inverter operating at 230V rms 50Hz with an output power of 300W. This is my first time designing something like this.I'm using the SG3525 to generate the complementary PWM signals to drive the mosfets at a frequency of ~100kHz.



Theres an issue with my output volate and I can't figure out the reason.


X3 drain voltage (Green)
X1 drain voltage (Blue)
Output voltage (Red)


Q. Is my output resistor sized correctly?