Homemade home inverter circuit diagram

Homemade home inverter circuit diagram (I)

The circuit is shown in Figure 1. When switch K1 is turned to the "inverting" position, BG1 is turned on, and the astable multivibrator composed of the time base circuit NE555 and peripheral components begins to oscillate, and its charge and discharge time constants are adjustable. If R1=R2 is selected, the duty cycle of the output pulse is 50%, and the oscillation frequency of the multivibrator is f=1.443/(R1+R2+2W)C2. The component values ​​in the figure can adjust the oscillation frequency to 50Hz. The oscillation pulse is output from the active pin, and the waveform is a square wave. The square wave is coupled by C4 and integrated by R3 and C5 to become a triangular wave. This triangular wave is integrated by R4 and C6 for the second time and R5 and C7 for the third time, becoming an approximate sine wave, which is coupled to the BG2 is amplified by BG2 and output on the L2 coil of B1. When the voltage on the upper end of L2 is positive, D4 ​​is turned off and D3 is turned on, so that BG4 and BG6 are turned off, and BG3 and BG5 are turned on. The current flows from the positive electrode of the battery → L1 of B2 → BG5 → the negative electrode of the battery; when the voltage on the upper end of L2 is negative, D3 is turned off and D4 is turned on, so that BG3 and BG5 are turned off, and BG4 and BG6 are turned on. The current flows from the positive electrode of the battery → L2 of B2 → BG6 → the negative electrode of the battery. BG5 and BG6 are turned on and off alternately, and a positive and negative symmetrical sine wave is synthesized by transformer B2, and then boosted by L3 and sent to the inverter output sockets CZ1 and CZ2 for use by electrical appliances. At the same time, LED1 (red) lights up to indicate the inverter state.

When the switch is turned to the "Charge" position, the mains electricity is stepped down by transformer B2, full-wave rectified by D5 and D6, and current limited by R11 to charge the battery. At the same time, LED2 (green) lights up to indicate the charging status.

Component selection and fabrication

The components in this circuit are all commonly available and can be selected according to the values ​​shown in the figure. B1 uses a radio output transformer, which should have a large core and thick wire diameter. The coil originally connected to the speaker is connected to the L2 position. BG3 and BG4 are composed of two 9013 and 9012 in parallel, as shown in Figure 2 and Figure 3. BG5 and BG6 are composed of four 3DD15 in parallel, as shown in Figure 4. The heat sink area of ​​BG5 and BG6 should not be less than 600cm2, and the B2 inverter transformer can be a finished product. The printed circuit board for the whole machine can be designed and made by yourself. The battery should have a capacity greater than 150Ah.

The debugging of this inverter only needs to adjust W so that the inverter voltage frequency is 50Hz.

Homemade home inverter circuit diagram (II)

The inverter introduced in this article has a simple circuit, low cost, easy maintenance, and high efficiency. Anyone with a little hands-on ability can make it. Although it does not have the high-end and complex switching power supply integrated circuit and field effect power amplification of the commercially available high-quality home inverter, its efficacy is not inferior. This machine has a quasi-sine wave output, a no-load current of less than 450mA, a load capacity of more than 300W, and an efficiency of more than 85%. Usually, it is more than enough to power electric fans, lighting bulbs, and electric soldering irons, or string 100W bulbs with TVs below 29 inches (due to the degaussing coil, the starting current is too large, so the bulbs must be started in series. If the degaussing coil is unplugged, the series bulbs can be used), which brings great convenience to life and maintenance. Faults will not cause voltage increases or burn electrical appliances. The author has used it for more than a year and has not seen any problems. The circuit is shown in the figure.

Working principle: After the 12V power supply is turned on, the multivibrator composed of V1, V2, R1-R4, C1, and C2 is powered on and starts to oscillate, and the collectors of V1 and V2 output positive polarity square waves close to 50Hz in turn. After being integrated and shaped into a quasi-sine wave by the integration circuit composed of C3 and R5, C4 and R6, it is inverted and amplified by V3 and V4 to stimulate V5 and V6 respectively, so that the final power tubes V7 and V8 are turned on and off in turn, and their collector currents flow through the primary windings L1 and L2 of the transformer to induce a quasi-sine wave high voltage output of about 50Hz on the high-voltage side of the transformer.

Component selection: Most of the components of this machine can be removed from waste circuit boards. V5 and V6 use D880 or C2073. V7 and V8 are made of three 3DD207 in parallel, with parameters of 200V/5A/50W, and can also be replaced by 3DD15D. The adjustable resistor RP can be removed from the tail board of an old color TV. There are no special requirements for the other resistors and capacitors. Coils L1 and L2 are 1.62mm enameled wires, each with 50 turns. L3, L4, and L5 are all made of Φ0.53mm enameled wires, with 12 and 12,945 turns respectively. The power tube can be equipped with a heat sink as large as possible. This machine is equipped with a heat sink with a width of 150cm. The transformer core should have an effective cross-sectional area of ​​more than 20cm2. You can use a sufficiently large core of a waste battery charger or a toroidal power transformer core on an amplifier. The toroidal transformer core is used.

Production and debugging: After all the power tubes are installed on the heat sink, all the other components are welded on the power tubes by scaffolding welding, and there is no need to make a circuit board. Since V1, V2 and the components that make up the oscillation circuit will cause the amplitude of the oscillation signal output by the collectors of V1 and V2 to be inconsistent due to the difference in characteristics, resulting in excessive no-load consumption, so the adjustable resistor RP is used to adjust the balance of the oscillation circuit. The voltage stabilizing circuit composed of VD and R7 is a necessary part to ensure the stable operation of the oscillation circuit, and can solve the problem of imbalance in the oscillation circuit caused by the drop in battery voltage. When testing and debugging, first adjust RW to the middle position, connect an ammeter in series to the 12V power supply end, start the machine without load, adjust RP to minimize the current, and then connect a 60W bulb to the load end; adjust RP to minimize the current, repeat the no-load and load adjustment for many times until the current can no longer be adjusted. At this time, listen close to the transformer, and the noise should be minimal. If the balance is not adjusted, the noise is very loud, and you can hear the noise even if your ears are not close. The emitters of V5 and V6 are connected to the bases of V7 and V8 in reverse phase through windings L3 and L4, respectively, which can deepen the saturation and cutoff depth of V7 and V8. It is beneficial to improve the efficiency of V7 and V8. Note that the phases of L3 and L4 must be correct. If they are connected incorrectly, although there will be output at the high-voltage end, the output voltage is not high and the load capacity will be very poor. After debugging, you can find a used computer power box. Put the whole machine in it, and use its cooling fan to dissipate heat.