Understanding the Functions, Types of Inverters, and How to Choose the Best Solar Inverter

What is an Inverter?

An inverter is a device that converts direct current (DC) power (from solar panel or power storage) into alternating current (AC) power, which is typically used by household appliances. Most commonly, the output is a 220V, 50Hz sine wave. Inverters are essential for a wide range of applications, including air conditioners, home theaters, power tools, computers, washing machines, and many more electrical devices.

In countries with high vehicle ownership, like the U.S. and Europe, inverters are particularly useful for outdoor activities like work trips or vacations. They allow users to connect batteries to inverters for powering various appliances and tools while on the go. For smaller inverters, ranging from 20W to 150W, you can connect directly via the car‘s cigarette lighter. For higher power demands, larger inverters require a direct connection to the car‘s battery.

When the grid fails,By connecting household devices to an inverter and energy storage batteries, Appliances can access AC power in a flash. This makes it possible to use electronics like UPS power.

What is the Role of an Inverter?

1. Maximum Power Point Tracking (MPPT)

Solar panels‘ current and voltage fluctuate based on sunlight intensity and panel temperature, affecting their overall power output. Inverters feature MPPT (Maximum Power Point Tracking) technology to ensure maximum power is harvested. MPPT optimizes the power conversion from solar panels by continuously adjusting the electrical operating point to ensure maximum efficiency.

Studies show that systems equipped with MPPT can increase power generation by up to 50% compared to systems without MPPT. So, while solar panels generate electricity, the inverter ensures you can get the maximum possible output from your solar energy system.

2. Anti-Islanding Protection for Grid Safety

Many assume that their solar system will continue working during grid outages. However, most systems are designed to shut down when the grid fails, a feature enabled by the inverter‘s anti-islanding protection. This feature prevents the system from sending power back to the grid during an outage, which could endanger utility workers and cause system instability. When the grid voltage drops to zero, the inverter ceases operation as a safety precaution.

3. Automatic Operation Based on Solar Output

Inverters can automatically start and stop based on the power generated by the solar panels. As sunlight increases during sunrise, solar radiation intensifies, and the inverter activates once the panels produce sufficient power. Throughout the day, the inverter continuously monitors solar panel output and stays operational as long as the panels generate enough energy to meet the inverter‘s requirements. Even on cloudy or rainy days, the inverter can function efficiently. When panel output diminishes, such as at sunset, the inverter automatically switches to standby mode.

Types of Inverters

1. Based on Power Flow

Active Inverters: These inverters are connected to the grid and regulate the current to allow efficient power distribution without directly feeding into the load.

Passive Inverters: These directly feed power into the load without interacting with the grid. They convert DC power into AC at a specific or adjustable frequency, depending on the load requirement.

2. Based on Grid Connectivity

Off-Grid Inverters: Designed for systems that operate independently of the power grid, often used in remote or backup power setups.

Grid-Tied Inverters: These inverters are integrated into the public power grid and are designed to export excess electricity produced by solar panels to the grid, often supporting net metering.

3. Based on Topology

Two-Level Inverters: Simplest type, commonly used in smaller applications.

Three-Level Inverters: Provide better output waveform quality and are used in medium-sized systems.

Multilevel Inverters: Offer superior efficiency and lower harmonic distortion, typically used in large-scale or industrial applications.

4. Based on the Power Rating

High-Power Inverters: For large-scale industrial and commercial applications.

Medium-Power Inverters: Suited for moderate energy consumption needs, such as mid-sized businesses.

Low-Power Inverters: Used in small-scale or residential applications.

How to Choose the Right Inverter

1. Rated Output Voltage

The inverter should deliver stable AC voltage within the specified input DC voltage range. The rated voltage accuracy should be within 3% to 5% during normal operation and within 8% to 10% during dynamic conditions such as load changes or interference.

2. Voltage Imbalance

For three-phase systems, the voltage imbalance (ratio of negative sequence to positive sequence components) must remain below a defined limit, typically in the range of 5% to 8%.

3. Output Waveform Distortion

When the solar inverter generates a sinusoidal output, the maximum allowable waveform distortion or harmonic content must be regulated. The total harmonic distortion (THD) of the output voltage should not exceed 5% for general systems, with single-phase systems allowing up to 10%.

4. Rated Output Frequency

The output frequency of the inverter‘s AC voltage must be stable, generally at the standard grid frequency of 50Hz, with a tolerance of 1% under normal working conditions.

5. Load Power Factor

This parameter reflects the inverter‘s ability to handle inductive or capacitive loads. For a sinusoidal output, the typical load power factor should range from 0.7 to 0.9 (lagging), with a nominal value of 0.9.

This refined guide provides a more in-depth and technical understanding of inverters, highlighting their role in power conversion, grid safety, and system optimization. Whether for residential, commercial, or industrial applications, understanding inverter features and types helps users make informed decisions, ensuring efficiency and reliability in their energy systems.

Voltage Regulator Inverter 0 Sencond Transfer Time

Main Features:

• Dual outputs, for smart load management
• Maximum PV input current increases to 27A
• Zero (0ms) transfer time to protect mission-critical loads such as servers and ATMs
• High PV input voltage range
• Touchable button with large 4.3 colored LCD with multiple communications
• Selectable high power charging current
• Built-in Wi-Fi for mobile monitoring (App is available)
• Configurable AC/Solar input priority via LCD setting
• Reserved communication port for BMS (RS485 or CAN-BUS)
• Supports USB On-the-Go function
• Parallel operation up to 9 units
• 2 years warranty