Analysis of modified sine wave inverter

August 10, 2024

What is a modified sine wave inverter

A modified sine wave inverter is a device that converts direct current (DC) into alternating current (AC). The AC waveform it produces is close to a sine wave, but not exactly the same, hence the name “modified sine wave”. Modified sine wave inverters are commonly used in homes, outdoor activities, and small industrial equipment because they are low cost and suitable for most common appliances.

Introduction to the main components

Modified sine wave inverters consist of several key components, including:

DC input circuit: receives DC power (such as a battery) and performs filtering and EMC processing.
Inverter bridge: consists of power switching devices (such as IGBT, MOSFET, etc.), and realizes the conversion of DC to AC by turning on and off the switch tube.
Control circuit: generates a specific PWM control signal to drive the switch tube in the inverter bridge, thereby outputting a modified sine wave voltage.
Output filter circuit: filters the square wave or trapezoidal wave output by the inverter bridge to make it closer to a sine wave.

How a modified sine wave inverter works

After the DC power supply is filtered by the input circuit and EMC processed, it provides a stable DC voltage for the inverter bridge.
The control circuit generates a specific PWM control signal to drive the power switch tube in the inverter bridge to turn on and off according to a certain rule.
The square wave or trapezoidal wave voltage output by the inverter bridge is filtered by the output filter circuit to obtain a modified sine wave voltage that is approximately a sine wave.
The modified sine wave voltage is supplied to the load for use.

Advantages and disadvantages

Pros	Cons
Improved output waveform compared to square wave inverters, with reduced harmonic content	Output waveform still differs from pure sine wave and contains some harmonics
Relatively simple structure and lower cost	Not suitable for inductive loads such as motors and transformers
Suitable for resistive loads like incandescent lamps and heaters	May cause interference with certain sensitive electronic devices

Common types

Single-phase modified sine wave inverter: outputs single-phase AC power, with low power, generally below 500W.
Three-phase modified sine wave inverter: outputs three-phase AC power, with high power, up to several kilowatts.
High-frequency modified sine wave inverter: has a high switching frequency, generally above 20kHz, with small size and light weight.
Power frequency modified sine wave inverter: has a switching frequency of 50Hz or 60Hz, requires a larger transformer and filter, and is larger in size and weight.

How to choose a suitable modified sine wave inverter

When choosing a modified sine wave inverter, you need to consider the following factors:

Load type: Modified sine wave
inverters can be used for resistive loads, while pure sine wave inverters are required for inductive loads.
Power size: Select an inverter with appropriate power according to the load power, and leave a certain margin.
Input voltage: Select an inverter with corresponding input voltage according to the DC power supply voltage.
Usage environment: In outdoor or harsh environments, you need to choose an inverter with corresponding protection level.
Brand and quality: Choose a brand with good reputation and reliable quality, and check the prod
uct certification and warranty policy.

Analysis of modified sine wave inverter

What is a modified sine wave inverter

Introduction to the main components

How a modified sine wave inverter works

Advantages and disadvantages

Common types

How to choose a suitable modified sine wave inverter

Comparison of waveforms of modified sine wave and pure sine wave

Table of Contents

Excellent! share to:

Improve again: high-quality power inverter and energy storage device

JYINS New Energy

Products

Resources

Contact Info

Request a Quote