What is the issue with my boost converter design and how can I fix it?

[TonyStewart]

This design is pointless until you define the load in watts and nF load capacitance, for which all piezo's are rated.
Diode capacitance will also impact results. As always, better design specs. results in a better design.

 

[core7916]

I hope you realized 390 uF was deleted for a good reason.

What is the real piezo load in nF, ohms?
View attachment 326517

sir the piezo has 1uf capacitence and 200k ohm resistence, i dont know exactly how much power is required to actuate this, since i dont know how much current it takes.

 

[Baluncore]

sir the piezo has 1uf capacitence and 200k ohm resistence, i dont know exactly how much power is required to actuate this, since i dont know how much current it takes.

I assume you will switch the DC voltage from the booster to drive the piezo transducer.
What is the piezo transducer application?
Do you know the piezo frequency and voltage?

The average current required from the boost supply will be proportional to drive voltage, and to the switching frequency.
Piezo capacitance, C; charge, q; voltage, v; current, i; time, t; frequency, f; power, W.
C = q/v; q = i·t; C = i·t/v; t = 1/f; C = i/(f·v); i = f·v·C; W = f·C·v².

 

[core7916]

I assume you will switch the DC voltage from the booster to drive the piezo transducer.
What is the piezo transducer application?
Do you know the piezo frequency and voltage?

The average current required from the boost supply will be proportional to drive voltage, and to the switching frequency.
Piezo capacitance, C; charge, q; voltage, v; current, i; time, t; frequency, f; power, W.
C = q/v; q = i·t; C = i·t/v; t = 1/f; C = i/(f·v); i = f·v·C; W = f·C·v².

its an piezo injector, the frequency of piezo in varies based on rpm selection, max 140hz,
i am not sure about voltage , maybe between 100- 150v it may open.

 

[Baluncore]

Then here is a quick estimate of the load for modelling a voltage booster.
Average current; i = f·v·C = 140 Hz * 150 volt *1 uF = 21. mA .
W = 21 mA * 150 volt = 3.15 watt .
For 5% ripple, reservoir capacitance, Cr = 1 uF * (100/5) ≈ 22 uF .
Resistive load for testing booster = 150 volt / 21 mA = 7143. ohms .
So model or test, a 22 uF reservoir capacitor, with a 6k8 resistive parallel load.

 

[TonyStewart]

How many injectors sharing the same HV?

You must define all the parameters of the injector pulses before you can define all the supply parameters before you can make a design. ok? Please do this.

Some injector profiles look like this if it is a fuel injector.

e.g. Courtesy Bosch

You should state all the goals of this design. e.g. Better fuel efficiency, longer injector life, etc
or just learn how to drive an injector and measure all injector characteristics.

If you want to master the art of SMPS electronic design, then you buy some of his latest books from one of the best teachers and experts on SMPS design Chris Basso, On Semi. https://cbasso.pagesperso-orange.fr/Spice.htm

If you are not that motivated then try these;

You can download the PDF versions and the working MathCAD files.