The inverter is designed to produce 220-volt alternating voltage from low direct voltage. Connects to any 12-volt source, incl. to the car battery through the cigarette lighter socket. The load power can reach 2500 W and is limited primarily by the power of the output transformer and the load capacity of the cigarette lighter socket.
- simple from a circuit design point of view;
- requires minimal adjustment;
- assembled from available components.
Electrical circuit of the inverter
An integrated controlled multivibrator CD4047BD with elements for adjusting the repetition rate of generated pulses is used as a key component of the device; the power part is assembled on paired field-effect transistors. To obtain an output voltage of 220 V, a step-up transformer is used, the inputs of the primary windings of which are connected directly to the terminals D (drains) of the power transistor assemblies.
Power final stages A are assembled on paired field-effect transistors.The final stage circuit is shown below.
200-ohm resistors in the gate circuit ensure equalization of currents across individual transistors.
Electronic components used in the device
To assemble the circuit you need:- CD4047BD controlled multivibrator microcircuit - http://alii.pub/5xga2j
- three resistors 220 Ohm power 0.25 W - http://alii.pub/5h6ouv
- 1000 µF electrolytic capacitor - http://alii.pub/5n14g8
- 47 nF ceramic capacitor - http://alii.pub/5n14g8
- variable resistor 12 kOhm - http://alii.pub/5o27v2
- four powerful field-effect transistors IRFZ44N - http://alii.pub/5ct567
- four resistors 200 Ohm power 0.25 W - http://alii.pub/5h6ouv
- step-up transformer with a transformation ratio of 20.
Features of assembling and setting up the inverter circuit
It is recommended to mount the components of the low-current part of the circuit on a printed circuit board. To install a multivibrator microcircuit, it is advisable to use a 14 or 16-pin mounting block.
Field-effect transistors of power modules “A” are installed in one or two rows on a copper or aluminum radiator. In the case of an in-line installation, its functions may well be performed by a block about 10 cm long and with a cross-section of 1.5 x 1.5 cm, in which holes are drilled and tapped for attaching transistors “for screws”.
Part of the circuit is assembled by surface mounting.
The transformer was taken from a broken uninterruptible power supply.
Solder the board to the transistors.
When setting up the circuit with a variable resistor, the pulse generation frequency is set to 50 Hz.
There is some difference in the shape of the output voltage from the sinusoidal one, because The CD4047BD multivibrator generates rectangular pulses, the fronts of which are partially smoothed by a transformer.The increased coefficient of nonlinear distortion does not matter for the bulk of the loads.
