About Single Phase Full Bridge Inverter | New Topic 2025

In this note, we are going to know about Single Phase Full Bridge Inverter, and about its specifications, circuit diagram, operation, advantages, disadvantages, and applications. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

What is Single Phase Full Bridge Inverter?

A Single Phase Full Bridge Inverter is a DC to AC inverter that transforms a set DC voltage to an AC voltage. To control the polarity and magnitude of the output voltage, four switches (transistors or thyristors) are connected in an H-bridge configuration. These inverters are commonly utilized in industrial settings, uninterruptible power supplies (UPS), and renewable energy systems.

📌 Specifications of Single Phase Full Bridge Inverter

• The input voltage is typically ranges from 12V to 400V DC.
• This circuit is generated the AC output voltage from 110V or 230V RMS (depending on the application).
• The generated output frequency is ranges from 50 Hz or 60 Hz.
• Switching devices are used here like MOSFETs, Thyristors, and IGBTs as well.
• The efficiency is high around 90% to 97%.
• The output power is depends on the design, typically from a few watts to several kilowatts.

Single Phase Full Bridge Inverter Circuit Diagram

Here is the circuit diagram of Single Phase Full Bridge Inverter –

• Four switching devices (Q1, Q2, Q3, Q4): Connected in H-Bridge configuration.
• DC Source: It is provides the input DC voltage.
• Load: Connected between the output terminals of the bridge.
• Gate Driving Circuit: Controls the switching of transistors or thyristors.

Single Phase Full Bridge Inverter Working

• The inverter operates by turning on and off the switches in a specific sequence to create an alternating output voltage.
• In one half cycle:
  • Q1 and Q4 are turned ON, and Q2 and Q3 are OFF. This applies a positive voltage across the load.
• In the other half cycle:
  • Q2 and Q3 are turned ON, and Q1 and Q4 are OFF. This applies a negative voltage across the load.

Output Voltage Equation

The instantaneous output voltage of a single-phase full bridge inverter is stated as:

• For Square Wave Operation, the output voltage is expressed by –

Where;

1. Vdc = Input DC Voltage
2. ω = Angular Frequency ( ω = 2πf, and f is the output frequency )
3. sgn(sin(ωt)) = Signum function that outputs +1 or -1 depending on the sign of sin⁡(ωt).

• For Pulse Width Modulation Operation or PWM Operation, the output voltage is expressed by –

Where;

• M_a = Modulation Index, which ranges from 0 to 1.
• sin(ωt): Desired sinusoidal output waveform.

Output Current Equation

The current depends on the load connected to the inverter. For pure resistive load, the output current is expressed as –

Where;

• V₀(t) = Output Voltage
• R = Amount of Load

Advantages of Single Phase Full Bridge Inverter

Here are the lists of single-phase full-bridge inverter advantages –

• The output efficiency is high due to low switching losses.
• This circuit is suitable for portable applications.
• It has low harmonic losses.
• The operation of this circuit is both, like bidirectional operation.
• The power ratings can be adjusted by selecting appropriate switches.

Drawback of Single Phase Full Bridge Inverter

Here are the lists of single-phase full-bridge inverter disadvantages –

• The switching of this circuit can generate Electromagnetic Interference (EMI).
• This circuit is requires a gate driver circuit.
• For high power applications, it requires a power cooling system.

Single Phase Full Bridge Inverter Applications

Here we have listed some important applications of this circuit –

• UPS Systems: Supplies AC power during grid outages.
• Industrial Drives: Drives for AC motors and pumps.
• Renewable Energy Systems: Converts DC from solar panels or batteries to AC.
• Electric Vehicles (EVs): Powers AC motors in Electric Vehicles.
• Household Appliances: Powers devices requiring AC from a DC source.
• Telecommunications: Provides reliable power for communication systems.