Switch mode inverter

9W2ZSU = http://qrz.com/db/9w2zsu

MY INVERTER RESEARCH – SMPS/LINER 200,250,500,600,1000Watts Created by :Salim-M/ CallsignAmateur 9W2ZSU…[email protected].. 4.1. 2012 -Malaysian WARNING! Build SMPS inverter is VERY DANGEROUS!! Please take all precaution ..electric shock Can cause serious injured or death.. You must read below before start build this circuit. -

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This is switching mode inverter (same 100% circuit topology with commercial inverter) SMPS mode more efficient then traditional push pull liner transformer inverter.what we all know liner transformer is expensive,bulky ,more heat and UNSTABLE in solar hybrid system. This circuit in modified sine wave! Has 30% harmonic .you can run mofied sine wave to ac motor but generate more heat than pure sine wave inverter ,others device like computer,TV,lighting,etc no problems run with mod sine wave. You will need OSCILLOSCOPE or the project will be very much harder to build and test. A design such as this relies on careful measurements and great care to make certain that it will perform as expected. Attempting this without an oscilloscope is NOT recommended. You must have 36 ohm 5w resistor for discharge 400v capacitor voltage storage Large heatsinkfor all mosfets..heat will increase Rds(on), and that will make the heatsink hotter, and – BANG!!! Always take CAREFULL this circuit run very high voltage! Make sure dischare all capacitor after testing circuit. Most critical part is you must self winding torodial transformer! ..ferrite core has two type ETD and TORODIAL..i am choosen torodial because ETD type hard to find in market..commercial inverter use ETD but both work same

picture below is my SMPS inverter circuit topology


9W2ZSU = http://qrz.com/db/9w2zsu Circuit diagram below is my full 1000W SMPS inverter circuit

Circuit diagram below is simple 600w SMPS inverter version



1ST STEP CONSTRUCTION. TRANSFORMER CONSTRUCTION -

The most critical part is winding transformer.. Has two type ferrite transformer – ETD and TORODIAL…because hard to find ETD wire wound in market ,torodial was choosen…both torodial and ETD work same.

MANDATORY COMPONENT -

NTC resistor -for prevent inrush current surge what can cause H bridge mosfet BLOW Fast Recovery Diode – this SMPS need fast diode..if use normal diode will cause entire circuit less power output then expected. DO NOT alter voltage limiter resistor value-(feedback dc bus voltage at pin 1) alter this resister value can cause output ac voltage increase or decrease.

FIRST TIME START UP PROCEDURE -

Set oscilloscope probe.clamp it at TP1 and TP2 test point Turn on 12v main power source circuit and set 50hz frequency at 100k pot DO NOT touch any circuit with hand.!! electric shock!! this inverter can KILL you! After done set frequency, please discharge 330uf 400v capacitor with 36R 5W resistor! Use digital TRUE RMS multimeter for measure output ac voltage.do not use cheap china multimeter will give you false reading voltage.

BELOW IS MODIFIED SINE WAVE when TP1 and TP2 connected

H bridge mosfets Output (AC) modified sine wave (DANGER!)



FERRITE TRANSFORMER SELECTION. PICTURE BELOW IS TRANSFORMER TORODIAL CORE (easy to find in market)

PIC BELOW IS TRANSFORMER ETD CORE

TRANSFORMER CALCULATION A good starting point is using 5 turns for each primary (that is, 5 turns, centre tap and another 5 turns IN THE SAME DIRECTION). To calculate the number of turns of the secondary winding, multiply by the turns ratio. For example, if you want to build a +/- 400VDC bus supply from 12VDC, the turns ratio is 400V/12V=33.3 approx, so 33.3 x 5 = 166T (The 5 is primary) The secondary turn is 166T (better 176 turns, to overcome the diode losses) . You MUST use enamelled copper wire for all the windings. Keep also in mind that when working with high frequencies, the effective section of the wire is much smaller than the physical one, due to the "skin" effect (the current concentrates only in the outer part of the wire). As high currents are involved here, the section of the wire is very important, (if you don't want the enamel to fuse due to the heating produced by the resistive losses of the wire and short all the windings). A good practice is to use several thinner wires in parallel rather than a single thick one. This also eases winding. For example, three AWG 13 diameter wires can form a suitable primary for a 1000w DC bus supply.Three AWG13 winding in PARALLEL The same applies to the secondary, although the current is reduced so you can use less wires



TORODIAL WINDING STEP.

Step 1 : enamel copper wire

step 2 : start wind secondary

finish up winding secondary

Step3: wind primary wire

primary wire finish up wind 5 turn each ready for assamble

For perform 1200w you will need two ferrite torodial core for high power dc-dc converter with high switching frequency 50-60khz



FERRITE TORODIAL SPEC

I am use this Ferrite torodial spec: -

FT – 37 – 77 OD – 37mm ID – 23mm Height – 15mm Material code -77

This single toroid capable supply load 600w continuously at 55khz frequency

Winding technics for secondary.

Becareful..make sure double check your winding core before assamble..wrong winder will cause short circuit or blow the power mosfet..all wire winding in one direction..follow the step number.



FERRITE TOROID,IRON POWDER AND IRON CORE Toroid has two type. -

Ferrite Iron powder

Do not use iron powder toroid..or the project will failed..the iron powder has lower ‘Q’ For application dc-dc converter need high ‘Q’ rating,high volume resistivity and permeability. FT ferrite was choosen..material type 77



FERRITE TOROID MATERIAL.



COMPARITION FERRITE TOROID VS IRON CORE -

Most popular now days ferrite transformer used in dc-dc converter/inverter 1st generation inverter was use iron core transformer since late 80 era Simple component and easy to build for beginner electronic for liner inverter but more costly especially transformer price..Efficiency only 50% or less. SMPS inverter only build by expert electronic coz expose to high voltage, sensitive part and need complete measurement equipment such oscilloscope and true RMS multimetr Cost For every single 400watts liner inverter you can make two SMPS 1200watts inverter...copper price always high mate!..cost for build SMPS very low.. High efficiency for SMPS Inverter..80 – 90% you can archive 90% if you build very proper especially winding transformer, high quality component mosfet,PCB and low ESR caps I never said commercial smps inverter not good..but they build for production that’s why use lower quality component for lower cost especially china made inverter. Most china made SMPS inverter use aluminum wire for transformer. not pure copper wire..aluminum transformer wire heat very fast if running at hot country and bang!!

The tiny ferrite FT-37 has more power if compare bulky iron core 9 – 0 – 9 400VA Iron core 9-0-9 400va -Price = RM 200.00 / usd 66.00 (expensive) -Maximum watts = 400 – 450watts -Efficiency = 50% or lower depend on battery voltage. only pro in high robust. Ferrite FT-37 toroid -Price = RM 3.00 / usd 1.00 (cheap) -Maximum watts = 500 – 600watt depend on switching frequency and high efficiency 80-90% 9W2ZSU = http://qrz.com/db/9w2zsu


MOSFET THERMAL & INSULATION. CLAMPING MOSFET&INSULATED WITH THERMAL CLOTH -Make sure clamping mosfet insulated with thermal cloth AND thermal transfer liquid -1200W application NEED big area heat sink for prevent IRF3205 mosfets over heating.additional high RPM cooling fan required. PIC BELOW IS CLAMPING MOSFETS ON HEATSINK + THERMAL LIQUID + THERMAL CLOTH

High RPM cooling fans..recycle aluminum SMPS casing fitted my 1200w inverter apply on my small solar system.



ANTI SURGE INRUSH CURRENT ISSUE Inrush current always damange sensitive component in smps application such h bridge power mosfet..inrush will occur if you using power tools exe drills,jigsaw and grider.this equipment need high surge current for start up.for prevent this inrush current flow in you inverter you must put NTC resistor.the resistor will absorb surge current from startup load. I was choosen NTC 10D-11 for protect my h bridge fet from blow up…at 600w application you will need minimum two NTC 10D wiring in series at ac output..at 1200w application need 3 pax NTC 10D also wiring in serie. NTC 10D – 11 spec: -

10D = 10ohm resistant 11 = 11mm width

I have blow dozen of mosfet IRF740 during this research.lucky this mosfet cheaper here. Most of fets blow because unbalance NTC resistor value..un proper cooling system and false frequency switching…now my inverter well perfect in term robust and power.

NOTE : The two circuit diagram 600w and 1200w just basic heart of inverter..i never put overload protection and low voltage shutdown coz I don’t want somebody use my circuit for commercial inverter…if you want..you create you self design the two protection overload and low voltage shutdown..



1st STAGE MY PROTOTYPE. PICTURE BELOW IS MY 1ST PROTOTYPE H BRIDGE CHOPPER 320VDC TO 220VAC

PICTURE BELOW IS MY 1ST PROTOTYPE DC-DC CONVERTER 12V TO 320VDC FOR 1000W SMPS 1000W SMPS NEED TWO TORODIAL CORE FT-37.



MY SMPS INVERTER APPLICATION. PIC BELOW IS 200W SMPS UPS SYSTEM FOR MY FISH AQUARIUM POWER BACKUPS.

PIC BELOW 600W my SMPS portable power pack (very use full) say no to stinky noisy GEN-SET

PIC Below 1200w SMPS for small solar hybrid system. this inverter work every day power up my small electronic workshop, my laptop, soldering iron, kitchen exhaust fan also work as power Backup if grid failure. This small solar system also save my electric bill about rm20.00 per month.

homebrew 1200w inverter + homebrew MPPT 20a solar charger + 120w mono panel + 12v 280ah bank 9W2ZSU = http://qrz.com/db/9w2zsu


ABOUT LINER INVERTER. THIS IS LINER TRADITIONAL INVERTER WITH BULKY TRANSFORMER (OLD TECH) THIS PROTOTYPE I LEARN WHAT IS INVERTER.LOOK SIMPLE BUT EXPENSIVE TO BUILD EXPICIALLY TRANSFORMER..

*LEFT PIC -150W PROTOTYPE USING PIC16F628A * RIGHT PIC – 250W LINER INVERTER (ANALOG) CIRCUIT DIAGRAM BELOW IS 250-500W LINER ANALOG INVERTER.Actually I like this kind of inverter in term of ROBUST ..you can put this inverter outdoor side.hard to damage..if overload or short circuit this inverter just suck a lot battery amps! And nothing any component part damage..the cons is efficiency is only 50% ,unstable voltage,bulky huge,expensive to build and not suitable application in solar hybrid system

ANALOG LINER INVERTER (MODIFIED SINE WAVE) CIRCUIT DIAGRAM



JUST TO SHARE MY OLD LINER INVERTER PROJECT

My First liner inverter 150w

My third gen liner inverter 250w

my second gen liner inverter 200w

liner inverter 300w in my early small solar system

CONCLUSION Lastly I suggest who want build inverter in a first step go for liner inverter before build more complicated SMPS inverter and I repeat BUILD SMPS inverter is more COMPLICATED than expected … INVERTER – most people says ‘BETTER BUY THAN BUILD’ its costly…yes its true for beginning...but..in my opinion when BUY, you only got ONE..but when you success BUILD..you can build thousand of inverter.. Cheers…sorry my poor English…un finish school..coz my teacher death early..  .thank you By –Ags Saleem , HAM callsign 9W2ZSU Malaysian.


Switch mode inverter

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