In this article you can find detailed step-by-step instructions for making a 220 V 50 Hz AC inverter from a 12 V car battery. Such a device is capable of delivering power from 150 to 300 W.
The circuit diagram of this device is quite simple..
This circuit operates on the principle of Push-Pull converters. The heart of the device will be the CD-4047 board, which operates as a master oscillator and also controls field-effect transistors that operate in switch mode. Just one transistor can be open; if two transistors are open at the same time, a short circuit will occur, as a result of which the transistors will burn out; this can also happen in case of improper control.
The CD-4047 board is not designed for high-precision control of field-effect transistors, but it copes with this task perfectly. Also, for the device to operate, you will need a transformer from an old 250 or 300 W UPS with a primary winding and a middle positive connection point from the power source.
The transformer has a fairly large number of secondary windings; you will need to use a volt-ohmmeter to measure all the taps and find a 220V network winding. The wires we need will give the highest electrical resistance of approximately 17 ohms, you can remove the extra leads.
Before you start soldering, it is advisable to double-check everything. It is recommended to select transistors from the same batch and the same characteristics; the capacitor of the driving circuit often has a small leakage and a narrow tolerance. Such characteristics are determined by a transistor tester.
Since the CD-4047 board has no analogues, you need to purchase it, but if necessary, you can replace the field-effect transistors with n-channel ones with a voltage of 60V or more and a current of at least 35A. Suitable from the IRFZ series.
The circuit can also operate using bipolar transistors at the output, but it should be noted that the power of the device will be much less when compared with a circuit that uses “field switches”.
Limiting gate resistors should have a resistance of 10-100 ohms, but it is preferable to use 22-47 ohm resistors with a power of 250 mW.
Often the master circuit is assembled exclusively from the elements indicated in the diagram, which has precise settings at 50 Hz.
If you assemble the device correctly, it will work from the first seconds, but when starting it for the first time, it is important to be on the safe side. To do this, instead of a fuse (see diagram), you need to install a resistor with a nominal value of 5-10 Ohms or a 12V light bulb, in order to avoid the transistors exploding if mistakes were made.
If the device operates stably, the transformer will make sound, but the keys will not heat up. If everything works correctly, the resistor (bulb) needs to be removed, and power is supplied through the fuse.
On average, the inverter consumes energy when the robot is idling from 150 to 300 mA, depending on the power source and the type of transformer.
Then you need to measure the output voltage, the output should be about 210-260V, this is considered a normal indicator, since the inverter does not have stabilization. Next, you need to check the device by connecting a 60-watt light bulb under load and letting it run for 10-15 seconds; during this time the keys will heat up a little, since they do not have heat sinks. The keys should heat up evenly; if the heating is not uniform, you need to look for where errors were made.
We equip the inverter with the Remote Control function
The main positive wire should be connected to the middle point of the transformer, but for the device to start working, a low-current positive must be connected to the board. This will start the pulse generator.
A couple of suggestions about installation. Everything is installed in the computer power supply case; the transistors should be installed on separate radiators.
If a common heat sink is installed, be sure to isolate the transistor housing from the heatsink. The cooler is connected to a 12V bus.
One of the significant disadvantages of this inverter is the lack of short circuit protection, and if it occurs, all transistors will burn out. In order to prevent this, you must install a 1A fuse at the output.
To start the inverter, a low-power button is used, through which plus will be supplied to the board. The power busbars of the transformer should be fixed directly to the radiators of the transistors.
If you connect an energy meter to the output of the converter, you will be able to see that the outgoing frequency and voltage are within the permissible limits. If you get a value greater or less than 50Hz, you need to adjust it using a multi-turn variable resistor, it is installed on the board.
To connect household devices to the car’s on-board electrical system, you need an inverter that can increase the voltage from 12 V to 220 V. There are sufficient quantities of them on store shelves, but their price is not encouraging. For those who are a little familiar with electrical engineering, it is possible to assemble a 12-220 volt voltage converter with your own hands. We will analyze two simple schemes.
Converters and their types
There are three types of 12-220 V converters. The first is from 12 V to 220 V. Such inverters are popular among motorists: through them you can connect standard devices - TVs, vacuum cleaners, etc. Reverse conversion - from 220 V to 12 - is required infrequently, usually in rooms with severe operating conditions (high humidity) to ensure electrical safety. For example, in steam rooms, swimming pools or baths. In order not to take risks, the standard voltage of 220 V is reduced to 12, using appropriate equipment.
The third option is, rather, a stabilizer based on two converters. First, the standard 220 V is converted to 12 V, then back to 220 V. This double conversion allows you to have an ideal sine wave at the output. Such devices are necessary for the normal operation of most electronically controlled household appliances. In any case, during installation it is strongly recommended to power it through just such a converter - its electronics are very sensitive to the quality of power, and replacing the control board costs about half the boiler.
Pulse converter 12-220V 300 W
This circuit is simple, the parts are available, most of them can be removed from a computer power supply or purchased at any radio store. The advantage of the circuit is its ease of implementation, the disadvantage is the non-ideal sine wave at the output and the frequency is higher than the standard 50 Hz. That is, devices that require power supply cannot be connected to this converter. You can directly connect not particularly sensitive devices to the output - incandescent lamps, iron, soldering iron, phone charger, etc.
The presented circuit in normal mode produces 1.5 A or pulls a load of 300 W, at a maximum of 2.5 A, but in this mode the transistors will noticeably heat up.
The circuit was built on the popular TLT494 PWM controller. Field-effect transistors Q1 Q2 should be placed on radiators, preferably separate ones. When installing on one radiator, place an insulating gasket under the transistors. Instead of the IRFZ244 indicated in the diagram, you can use IRFZ46 or RFZ48, which are similar in characteristics.
The frequency in this 12 V to 220 V converter is set by resistor R1 and capacitor C2. The values may differ slightly from those shown in the diagram. If you have an old non-working power supply for your computer, and it contains a working output transformer, you can put it in the circuit. If the transformer is not working, remove the ferrite ring from it and wind the windings with copper wire with a diameter of 0.6 mm. First, the primary winding is wound - 10 turns with the output from the middle, then, on top - 80 turns of the secondary.
As already said, such a 12-220 V voltage converter can only work with a load that is insensitive to power quality. To be able to connect more demanding devices, a rectifier is installed at the output, the output voltage of which is close to normal (diagram below).
The circuit shows high-frequency diodes of the HER307 type, but they can be replaced with the FR207 or FR107 series. It is advisable to select containers of the specified size.
Inverter on a chip
This 12-220 V voltage converter is assembled on the basis of a specialized KR1211EU1 microcircuit. This is a generator of pulses, which are removed from outputs 6 and 4. The pulses are antiphase, with a short time interval between them - to prevent the simultaneous opening of both keys. The microcircuit is powered by a voltage of 9.5 V, which is set by a parametric stabilizer on a D814V zener diode.
Also in the circuit there are two high-power field-effect transistors - IRL2505 (VT1 and VT2). They have a very low open resistance of the output channel - about 0.008 Ohms, which is comparable to the resistance of a mechanical key. Permissible direct current is up to 104 A, pulsed current is up to 360 A. Such characteristics actually make it possible to obtain 220 V with a load of up to 400 W. Transistors must be installed on radiators (with a power of up to 200 W it is possible without them).
The pulse frequency depends on the parameters of resistor R1 and capacitor C1; capacitor C6 is installed at the output to suppress high-frequency emissions.
It is better to take a ready-made transformer. In the circuit, it is turned on in reverse - the low-voltage secondary winding serves as the primary, and the voltage is removed from the high-voltage secondary.
Possible replacements in the element base:
- The D814V zener diode indicated in the circuit can be replaced with any one that produces 8-10 V. For example, KS 182, KS 191, KS 210.
- If there are no capacitors C4 and C5 of type K50-35 at 1000 μF, you can take four 5000 μF or 4700 μF and connect them in parallel,
- Instead of an imported capacitor C3 220m, you can supply a domestic one of any type with a capacity of 100-500 µF and a voltage of at least 10 V.
- Transformer - any with a power from 10 W to 1000 W, but its power must be at least twice the planned load.
When installing circuits for connecting a transformer, transistors and connecting to a 12 V source, it is necessary to use large cross-section wires - the current here can reach high values (with a power of 400 W up to 40 A).
Inverter with pure sine wave output
The circuits of daytime converters are complex even for experienced radio amateurs, so making them yourself is not at all easy. An example of the simplest circuit is below.
In this case, it is easier to assemble such a converter from ready-made boards. How - watch the video.
The next video shows how to assemble a 220 volt converter with pure sine wave. Only the input voltage is not 12 V, but 24 V.
And this video just tells you how you can change the input voltage, but still get the required 220 V at the output.
When it is necessary to create mains voltage in a car, special 12-220 converters are usually used. There are inexpensive standard inverters on sale for about 20-30 dollars. However, the maximum power of such devices is, at best, about 300 watts. In some cases, this power may not be enough.
You can get power for a powerful amplifier through small transformations. It is enough just to replace the secondary winding on a standard inverter. After this, you can get any value of the input voltage. For example, the power of a 400 Watt inverter will increase to 600 Watts.
To increase power at home, experts recommend using a simple method. It will be necessary to replace the high-power bipolar switches with IRF 3205.
An inverter is used for operation, to which it is possible to connect 4 pairs of output transistors. Therefore, the device, after carrying out the necessary work, will be able to produce a power of about 1300 watts. If you buy a ready-made inverter with such parameters, its cost will increase to 100-130 dollars.
It is worth noting that the traditional push-pull circuit of the device does not contain protection against overheating, short circuit and output overloads.
The generator is based on a TL 494 microchip, which has an additional driver. It is necessary to replace low-power bipolar transistors with domestic analogues (KT 3107).
In order not to use powerful switches to supply power, the inverter is equipped with a remote control circuit.
In the driving part of the device, special SCHOTTTKI diodes type 4148 are used (domestic KD 522 is also suitable). The transistor in the remote control circuit is replaced with KT 3102.
After this, you can move on to the most important part of the project - the transformer. This element is wound on a pair of glued 3000 NM rings. Moreover, the size of each of them is 45x28x8. For a tighter fixation, the rings can be wrapped with tape.
Then the rings are wrapped on top with fiberglass (the cost in the store is no more than $1). It is quite acceptable to replace this material with fabric electrical tape.
Fiberglass is cut into small strips about 2 cm wide and no more than 50 cm long. The material for work has high heat resistance, and thanks to the thin base, the insulation looks neat.
For the primary winding you need 2x5 turns of wire, that is, 10 turns with a tap from the middle. The work is carried out with a wire with a diameter of 0.7-0.8 mm, and 12 wires are used for each arm. The process is presented more clearly in the following photographs.
The tourniquet is stretched, and 5 turns are evenly wound on both arms, stretching them across the entire ring. The windings must be the same.
The resulting elements have four outputs. The beginning of the first winding must be soldered to the end of the second. The solder location will be a tap for a power voltage of 12 V.
At the next stage of work, the ring must be insulated with fiberglass and covered with a secondary winding.
The secondary winding increases the output voltage. Therefore, when carrying out work you need to be as careful as possible and follow all safety precautions. It is worth remembering that high voltage is dangerous. Installation of the device is carried out only with the power turned off.
The winding of the rings is carried out using a pair of parallel strands of 0.7-0.8 mm wire. The number of turns is about 80 pieces. The wire is distributed evenly throughout the ring. At the final stage, the product is additionally insulated with fiberglass.
When the inverter assembly is completed, you can begin testing it. The device is connected to a battery; for starters, a battery with a voltage of 12 V from an uninterruptible power supply will do. In this case, the “plus” of power will go to the circuit through a 100-watt halogen lamp. It is worth paying attention that this lamp should not be lit before or during work.
After this, you can proceed to checking the field keys for heat generation. With a correctly assembled circuit, it should be practically zero. If there is no input load, and the transistors overheat, then you need to look for a non-working component in the device.
If the testing is successful, you can install the transistors on one common heat sink. For this purpose, special insulating gaskets are used.
The circuit diagram in *.lay format is in the archive file and will be available after downloading.
12-220 Volt inverters are needed to power equipment if it is not possible to supply a household network. The peculiarity of the device is that it can be used to convert a direct voltage of 12 V into an alternating voltage of 220 V. Just a few decades ago this seemed almost unthinkable, but today, when there is a huge element base, it will not be difficult to make such a converter.
Inverter power
You can use a 12-220 car inverter while traveling. Any household appliance can work even in field conditions. But the maximum permissible load is small - a few hundred watts. The most powerful devices allow you to connect a load with a power of 2-3 kW, but the battery will quickly run out. Types of loads by current consumption:
- Reactive - partially consumes energy received from the power source.
- Active - energy is consumed to the maximum.
If you know exactly what load you will connect to the inverter, then calculating the maximum power will not be difficult. Let's say you plan to connect a load with a maximum power of 300 watts to the device. The power of the inverter itself should be about 25% more - such a reserve is quite enough. Therefore, to fully meet the needs, you need an inverter with a power of 375 W. But you won't find one like this on sale. Therefore, you need to choose a device with a power of 400 W - the closest in value.
Where can these devices be used?
The simplest type of 12-220 Volt voltage inverter is an uninterruptible power supply used in computer technology. But they have one big drawback - low power, the battery does not last long. And if the device is used in everyday life in conjunction with a mini-power plant (even a wind-powered one), then stable power is guaranteed. Typically, inverters can be found in the following designs:
- Security alarms.
- Heating boilers.
- Pumping stations.
- Computer servers and other systems.
In other words, they are used where a constant supply of 220 Volts is required. Household voltage stabilizers are nothing more than inverters. Only in them is the alternating voltage converted to constant, stabilized, after which it rises again to 220 Volts. Moreover, with the help of electrical semiconductor switches and a PWM modulator, it is possible to achieve an almost ideal sinusoid.
Features of the design
Inverters 12-220 Volts are used quite widely. Ordinary motorists use them as a power source on long trips. You can simply turn on an electric razor, hair dryer, TV, even boil a kettle. True, the battery will drain quickly. Therefore, it is better to use devices to power essential appliances and lighting.
The simplest homemade 12-220 V inverters can be made from several power transistors and a multivibrator. The device can be operated even in severe frost. But for hot weather it is necessary to provide additional cooling, otherwise the transistors will fail. A simple cooler from a personal computer just needs to be installed on a radiator for cooling semiconductor power transistors.
The simplest homemade inverter
Almost all commercially available inverters operate using high frequency current. Classic circuits, which were made on the basis of transformers, are completely forgotten, they were replaced by pulse designs.
Based on one K561TM2 microcircuit, consisting of two D-flip-flops, it is possible to make the simplest master path for an inverter. The circuit consists of a master oscillator, the role of which is played by DD1, as well as a frequency divider made on the trigger DD1.2.
Power transistors such as KT827 or KT819 are used for voltage conversion. Field effect transistors of the IRFZ44 type show very good results. With the help of a master generator, a sinusoid is generated, which is necessary for the normal operation of the structure.
Features of the inverter
To obtain a 50 Hz circuit, it is necessary to use a secondary winding and electrolytic capacitors and a load element connected in parallel to it. When there is no load connected to the output, the circuit does not work. As soon as you connect any consumer, the inverter will begin to convert the voltage of 12 to 220 Volts.
The output sinusoid is far from ideal. This is a huge drawback of such a scheme. To produce an increase in power, it is necessary to use more expensive and efficient types of transistors. Note the electrolytic capacitor that is connected to the output. It should be designed for a minimum voltage of 250 V. It will be better if this value is higher than 300 V.
Devices based on modern components
Such circuits can be used to power household appliances, fluorescent lamps, etc. In the design, power transistors of the KT819GM type are mounted on a radiator with a large area to improve cooling. The circuit contains a master oscillator based on the KR121EU1 logical element, by analogy as in the case discussed above, and field-effect transistors IRL2505 also work well.
The choice of the KR12116U1 microcircuit was not accidental - it has two-channel adjustment of power switches. Therefore, it is ideal for simple designs. The frequency that the master oscillator will produce depends on the passive elements used in the circuit. Using a signal from the generator, the semiconductors are opened and locked.
When the channels in the transistors are open, their resistance is only 0.008 Ohm - this is very little. Therefore, transistors with low power can be used. For example, if a transformer with a power of 100 W is installed at the output, a current of about 104 A will flow through the transistors in normal mode. In pulse mode, the peak value can be 350-360 Amperes.
Ready-made boards for assembling inverters
You can find ready-made modules on sale. They are boards on which are installed:
- Transformer.
- Semiconductor power switches.
- Radiator.
- Passive elements.
- Residual current devices, fuses.
Such an inverter 12 to 220 will produce a pure sine wave at the output, since it is manufactured at a modern facility. The cost of ready-made blocks is quite high. The lowest-power one will cost no less than 300-350 rubles, and that’s the wholesale price. The higher the power of the device, the higher its cost.
But before using such devices, you need to find a suitable housing. The board must be mounted in such a way that the internal space is well cooled. It is advisable to do additional forced cooling using a cooler from a personal computer. The 12-220 inverter, the diagram of which is shown above, must also be mounted in a reliable housing. The main thing is not to accidentally touch the high-voltage terminals.
A second life for uninterruptible power supply!
If you have an “extra” uninterruptible power supply whose battery is completely dead, you can still revive it. To do this you will need to make some small changes:
- Remove the old battery.
- Solder new wires to connect to the 12 Volt battery.
- At the edges of the wires, install terminals for connecting to the car battery. If the device will be used in a car, it can be powered from the cigarette lighter. But it is undesirable to do this - the high power of the device causes excessive heating of the wires.
To connect household appliances to an uninterruptible power supply, you need to make sockets. The easiest way is to make a carrier from an old surge protector and a piece of wire with a plug, which will include all the equipment.
Design features based on uninterruptible power supply
With a good battery with a capacity of 55 Ah, such a design can maintain normal temperature in an incubator for 100 eggs, for example, for up to a day. Any farmer knows how dangerous hypothermia is for incubators. True, the power of such a device is small; the air conditioner or refrigerator will not be able to work properly.
One drawback of this design is that the standard circuit will not be able to fully charge a car battery. Therefore, when the battery is completely drained, it is necessary to charge it from a normal device that produces a current of more than 5-6 Amps.
Homemade powerful inverter
To make a 12 V 220 3000 W inverter with your own hands, you will need knowledge of the basics of electrical engineering and installation skills. You will have to make several specific elements. One of them is a pulse transformer. With its help, the voltage is increased from 12 to 220 Volts. You also need to acquire several expensive elements. They are listed below:
- PWM modulator. Necessary for the operation of semiconductor switches. With its help, the operating frequency of the entire circuit is set. It should be noted that the switching frequency of power switches is several tens of thousands of times per second.
- Semiconductor transistors operating as power switches allow not only amplification of the signal, but also switching. They open and close, and when paired with a PWM modulator, they create an almost pure sine wave.
- Aluminum radiators with large surface area. The higher the power of the device, the larger the radiator area required.
- Foil material on which all elements are mounted. If desired, of course, you can perform wall-mounted installation, but it will take up too much space. You can make such a homemade 12-220 inverter with your own hands in a few minutes, but it will be unsafe to use if you do not take measures.
- Passive elements - resistors, capacitors.
- Connecting wires.
When manufacturing a device, several electromagnetic relays may also be required for switching. By the way, you can decide that instead of power switches it is permissible to use simple electromagnetic relays. There is only one thing - the switching speed is very high (40-60 thousand operations per second). Therefore, electromechanical devices cannot cope with this task.
Ready-made inverters
If you don’t want to make a 12V 220 3000W inverter with your own hands, you can purchase a finished product in a beautiful case, with a lot of connectors for connecting devices. But the price is too high. You can buy the cheapest one, whose power barely reaches 50 W, for 800-1000 rubles. And it will be enough to charge a laptop battery or power several LED lighting lamps. An electric hair dryer or curling iron can no longer be connected to such a device.
More powerful devices (over 2000 W) have a corresponding price. The cheapest 12-220 V inverter will cost 3000-5000 rubles. But it all depends on the manufacturer. High-quality, multifunctional devices produced by well-known companies can cost over 20,000 rubles. That is why people who are more or less versed in electrical engineering prefer to make a 12-220 inverter with their own hands. Fortunately, the elements for manufacturing can be found in the simplest power supply of a personal computer.
— when using low-power household appliances, especially in field conditions, there is a need to recharge their batteries. Therefore, in such cases, when there is no 220v power supply nearby, an inverter from 12 to 220 volts is very helpful.
I present to your attention a simple circuit of a DC voltage converter from 12v to 220v AC output. Initially, I was faced with the task of making an inexpensive, compact, low-power voltage conversion device. Therefore, it was decided to assemble it from the parts that I had on hand. The main components for assembling the inverter were components from an unnecessary computer power supply. But it is advisable to install a more powerful transformer. A low-power trans is not very suitable for such purposes; during operation it does not draw power more than 18-20 W. Radiators for cooling output transistors must be installed with a heat dissipation area based on more than 60 W of load.
Voltage converter circuit
The printed circuit board of the device must be placed in a housing that guarantees complete protection from the user touching high-voltage circuits.
Converter PCB
If you decide to use the inverter only to connect a TV or incandescent lamp to it, then you can do without a rectifier. By the way, the device works great with a compact fluorescent lamp, I tested it on a CFL with a power of 15 W - it starts up without problems. All components used were installed new, the only exception being the power transformer. Of course, in the future I have plans to make a couple more designs, taking into account the discovered features in the circuit and regarding the components.
The basic principle of operation of the circuit
DIY voltage converter 12-220 volts— a brief description of the circuit and the principle of its operation. This device, in principle, is nothing more than a push-pull pulse converter implemented on a TL494 pulse-width modulator. It is possible to use analogues of this PWM controller. Using this circuitry, the device turns out to be quite simple. High efficiency rectifier diodes are installed in the output circuit to double the voltage. However, the circuit can be used without the use of diodes, while obtaining an alternating voltage. For an electronic type ballast, direct current, as well as the polarity of the connection, does not matter. This is due to the fact that the electronic ballast circuit in the input circuit has its own diode bridge, assembled on fast-acting diodes.
Transformer
The converter circuit presented here uses an industrial high-frequency step-down transformer. Such trances are used in computer power supplies, only in this design it will act as the opposite of a booster. The step-down transformer can be removed from the AT power supply or from the ATX. A step-down or step-up transformer may differ from each other only in dimensions, everything else is the same. In principle, a transformer cannot be a step-up or step-down transformer; it all depends on its connection diagram.
- Capacitor C1 – has a nominal value of 1 nF, (coding on the case is 102);
- Resistor R1 – provides a range of pulses in the output circuit.
- Resistor R2 - together with electrolyte C1 provides the operating frequency.
If it is necessary to increase the frequency, you need to reduce the resistance R1; if you need to reduce the frequency, then we increase the capacitance of the electrolytic capacitor C1.
Field effect transistors
The voltage inverter uses powerful field-effect transistors, which are distinguished by their speed and do not require complex control circuits. The following keys have proven themselves to work well: IRFZ44N, IRFZ46N, IRFZ48N. Practice has shown that during long-term operation of the device the keys do not get very hot, so a radiator for cooling the transistors is not required for this circuit. If it is necessary to place transistors on a heat sink, they must be secured through insulating gaskets. And the screws for fastening them must be used in conjunction with the insulating washer-bushing, which are available in the computer power supply.
But still, for testing the device, a cooling radiator would be useful. Consequently, in the event of a short circuit at the output or an error in the circuit, the output switches will not immediately fail due to overheating. The overload protection circuit can be implemented using a chain - a fuse, plus a diode at the input.
For myself, I made a converter using the well-known IRF540N field-effect transistors.