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Simple Solar Inverter Circuit with Charger

This article teaches techniques to construct a circuit that can convert solar energy into AC electricity for a home.

It is made up of an inverter and a charger.

The charger charges a 12V battery using an 18V solar panel.

The inverter generates home AC current through a transformer using the battery power.

You can flip either using the battery to power appliances and charging it with a switch.

What is a Solar Inverter Circuit with Charger:

One can turn solar energy into electrical power that can be used and stored in batteries by connecting a solar inverter circuit with a charger.

The main parts of this kind of circuit are solar charger controller, an inverter and a battery bank.

Circuit Working:

Parts List:

TypeSpecificationQuantity
Resistors100Ω, 15Ω2 each
100Ω 1W1
SemiconductorsSchottky Diode 10Amp1
Zener Diode 15V 1W1
Transistor TIP351
Transistor 2N30552
Transformers9-0-9V 5Amp1
SPDT Switch 10Amp1
Battery 12V 25Ah1
Solar Panel 18V 5Amp1

Solar Panel:

Depending on how strong the sun is, the solar panels output voltage changes after transforming sunlight into electrical energy.

An emitter follower configuration is used for the TIP35 transistor.

The emitter voltage in this configuration is equal to the base voltage less the forward voltage drop across the base emitter junction.

By keeping the base voltage at about 15V the 15V Zener diode connected to the TIP35s transistor base helps keep it from getting too high.

The Zener diode controls the base emitter junctions voltage.

After adjusting for the 0.6V forward voltage loss across the transistor the emitter followers output voltage is controlled to about 14V.

The 12V battery can be charged with this controlled voltage.

Solar charging and inverter operation are the two modes that the SPDT switch offers the user.

The solar panel is connected to the battery for charging when the switch is in the solar charging mode.

The switch connects the battery to the inverter and disconnects the solar panel when it is in the inverter mode.

Inverter Circuit:

The 2N3055 transistors are configured in a cross coupled setup to create an astable multivibrator or a flip flop circuit.

This configuration allows the transistors to switch states alternately generating an alternating current AC output.

Transformer:

The 9-0-9V secondary winding of the transformer steps up the voltage produced by the inverter transistors.

The primary winding of the transformer is connected to the collector emitter circuit of the 2N3055 transistors.

Battery:

A source of energy storage is the 12V 25Ah battery.

In inverter mode the battery provides power to the inverter circuit and the inverter generates an AC output.

Circuit Operation:

Formulas:

Below are some simple formulas for emitter follower circuits which primarily deal with biasing the transistor and monitoring its AC characteristics.

DC Biasing:

    Base Current (IB):

    Because IB depends on transistor gain (β) and circuit configuration there is formula to calculate it:

    IB = (VCC – VBE) / (Rbias)

    where,

    Emitter Current (IE):

    The transistors current gain measures how base current and emitter current are related:

    IE = (β + 1) * IB
    

    AC Characteristics:

    Voltage Gain (Av):

    The voltage gain of emitter followers is almost 1 which differs between 0.8 and 0.999:

    Av = 1

    Note:

    These formulas provide a basic understanding.

    Make use of small signal equivalent circuits which requires additional component features for a more thorough examination.

    How to Build:

    To building a solar inverter circuit follow the below mentioned steps for connections:

    Solar Charger Circuit:

    Inverter Circuit:

    Testing:

    Solar Charging Test:

    Inverter Test:

    Note:

    Safety Precautions

    Conclusion:

    This is a simple tutorial and the actual construction may differ based on specific component values, ratings and the required power output.

    Always refer to datasheets for accurate information on component specifications.

    If you are not familiar with electronics consider seeking help from someone with experience or consulting with a professional.

    Also follow with local electrical codes and safety standards.

    References:

    Single Phase Solar inverter with smart Charge control

    Inverter for the Solar Panel

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