3000W Inverter with Inbuilt Charger using AT89C2051

The project posted here is a 3000W inverter with the facility like an inbuilt charger, over and under voltage control, temperature control, microcontroller-based, etc. We all know that an inverter is a device that changes DC power into AC power (just opposite of a rectifier). The general-purpose inverter (low or medium power inverter) used in our house converts 12V DC voltage to 220V AC. But the circuit posted here converts 24V DC (two 12V batteries connected in series) to 220V AC.

Circuit Description of Microcontroller Based 3000W Inverter with inbuilt charger

For a better description, the circuit of Microcontroller Based 3000W Inverter with inbuilt charger is divided into two main sections.

1. The inverter sections
2. Microcontroller section

Inverter Section | 3000W Inverter with Inbuilt Charger using AT89C2051:

Figure 1 shows the main circuit diagram of the inverter circuit. This section converts 24V DC to 220V AC and also charges the battery connected. This circuit is further into five different sub-sections.

1. Astable Multivibrator
2. Inverting Circuit
3. Automatic Change Over Unit
4. Charge Regulator

Astable Multivibrator:

An astable multivibrator is a device that oscillates continuously in a quasi-stable state without any external excitation. The circuit of a stable multivibrator is designed using a CMOS IC CD4047. The output frequency of this multivibrator is dependent upon the time constant and is always 180⁰ out of phase with each other. Variable resistor VR₆ is used to adjust the output frequency at which it oscillates. For the design published here, variable resistor VR₆ is so adjusted that the output will be 50Hz pulse width modulated signal. The two outputs from pin 10 and pin 11 are used to control the two individual MOSFET networks for inverting process.

Inverting Circuit:

The inverting circuit is designed using a series of MOSFET IRF150. This series is arranged in two parts as shown in figure 1. Both the arrangements are open and close alternately at regular interval of time because two individual output of IC₄ (CD4047) is connected to the gates of individual arrangement. The Drain of both arrangements is connected to the upper and lower limb of center tap transformer X₁ as shown in figure 1. When one arrangement is switched on other will be switched off and vice-versa, thus alternating voltage is produced. This section determines the power of the inverter. According to the above arrangement, the output power is about 3000W.

Automatic Changeover Unit:

The automatic changeover unit is designed using 5 individual relays (RL₁ through RL₅) as shown in figure 1. Transformer X₂ with bridge rectifier is used to power the relay circuit. All the input of these relays is connected to the output of bridge rectifier BR₂ thus when mains input is available at the input port all these relays (RL₁ to RL₅) start to energize. The energized electromagnetic pull the metal base connected with N/C to N/O. Relay RL₁ control input and output of the inverter. Relay RL₁ provides a LIVE line where neutral is provided by relay RL₃ and RL₄. Relay RL₂ provides charging voltage when mains is available.

Charge Regulator:

The Charge regulator circuit is designed using op-amp LM393 which compares the battery voltage. When the voltage of the battery is fully charged i.e. reaches up to 26.5V to 27.5V, the output of becoming high as a result transistor starts to conduct, and the piezo buzzer start to beep. This beep sound indicates that the battery is fully charged.

Microcontroller Section | 3000W Inverter with Inbuilt Charger using AT89C2051:

Microcontroller Section is built around AT89C2051 is shown in figure 2 which is used as an indicator circuit and temperature control unit i.e. used to display under or over voltage and also operate fan when the temperature rises above preset level i.e. 50⁰C. you can also build a temperature-controlled unit using Arduino.

The temperature monitoring and controlling section are designed using a thermistor. When the temperature of the unit exceeds the preset level, the voltage of the thermistor exceeds the voltage available at the non-inverting input thus the output of the comparator IC LM393 (IC2:B) becomes low as a result of a switch on the 12V DC fan, and also make pin P1.2 high (indicates the temperature is high).

When the battery voltage decreased to 18V DC the comparator output (IC₂:A) becomes low as a result Piezo buzzer PZ₁ start to beep which indicates the battery is low and needs a charge.

SOFTWARE | 3000W Inverter with Inbuilt Charger using AT89C2051:

The software is written in C programming language and compiled using Keil software. You can directly download and use the software below.

Click Here to Download Software

Check out other power supply and inverter circuits posted on besengineeringprojeccts.com

1. Offline UPS Circuit
2. Advance Emergency Light Circuit
3. Crystal controlled inverter | Verified Inverter Circuit
4. Advance Mini UPS

PARTS LIST OF MIROCONTROLLER BASED 3000W INVERTER WITH INBUILT CHARGER