pushpull boost problem

[madhu hegde]

Hello

i am doing project - 36v to 380v 1kw .boost using SG3525 chip with push pull configuration.

load regulation is the problem.at minimum load say 0.5A ok. but i put 1A load voltage dropping.

please check file and tell me the is it Number of primary / secondary turne ok ?

secondary diode bridge configuration ok ?

please help me...

 

[FvM]

First step is to determine in a measuremet where the voltage drop occurs, can be many thing like

- input voltage drop
- switch transistor voltage drop
- transformer leakage inductance

What's the operation frequency and primary duty cycle?

 

[BradtheRad]

36v to 380v

Your schematic shows the transformer with a higher step-up ratio than is necessary.

 

[D.A.(Tony)Stewart]

There are some basic methods of analysis here.
Load Regulation is related to output/load impedance ratio.
So high load regulation means high output impedance.

A transformer should be the input source impedance * n but coupling factor must be high, otherwise a high series impedance is added.

For 10% ripple on the bridge output, n=380/36 * (1+10%) so n =12 rounded up.
The reason is for any ripple on the bridge output under load, the DC average voltage will drop approximately the same amount.

Next record some results of V for various loads at every node and indicate the magnet design and all other factors such as frequency and switch resistance.