What is solar power inverter and how does it work?

Solar inverter, also known as PV inverter, is the "heart" of solar energy system. Its reliability and safety are directly related to the smooth operationof the solar energy system, its conversion efficiency directly affects the power generation efficiency, and its service life is directly related to thelife span of the photovoltaic power system, so it is necessary to understand the inverter in depth before purchasing it and find the most suitable one.

 

What's the difference between solar inverter and normal Inverter?

Like solar inverters, ordinary inverters use control circuits, transformers and switches to convert DC power to AC, but it is they that have the distinct difference: blocking diode and charge controller.

The solar inverter has a built-in blocking diode and charge controller that allows current to flow from the solar panel to the battery. However, it prevents current from flowing from the battery to the solar panel and potentially damaging other parts of the system.

The latter is the opposite of the blocking diode and is responsible for regulating the current and voltage from the solar panel to the battery to ensure that the battery is not overcharged.

 

What does an solar inverter do?

The PV inverter is the power electronics that connects the solar PV panels to the grid and keeps it synchronized with the solar panels, switching circuits, blocking diodes, batteries and charge controllers. Their main function is to convert the direct current generated by the solar panels into alternating current, but they do not produce any additional energy and are therefore not generators.

 

What different types of solar inverters are there?

Classify by function

• Power inverter:

  The power inverter usually is used to convert the direct current (DC) stored in the battery into a standard household alternating current (AC).

 

• Micro inverter:

  In addition to converting the DC current from the solar panels into AC current, it can transmit the AC power back to the utility. the AC output of the micro inverter can be synchronized with the frequency and phase of the utility.

 

• Inverter charger:
  Inverter charger is the collective name of off-grid inverter, grid tie inverter, and hybrid inverter.By integrating the functions of PV power generation and energy storage to battery, it can overcome the shortcomings of unstable power generation by weather changes. By storing power in the trough and outputting power in the peak, the peak power generation of the utility can be greatly reduced and the capacity of grid can be greatly increased, which can improve the utilization rate of the grid.
  
  The inverters can also be classified as pure sine wave inverter and modified sine wave inverter according to the waveform of the output current, which can be detailed in this article.

How does an inverter work?

While the PV array transmits DC power to the inverter, the DC electric rapidly transfers energy back and forth through the inverter. During this process, the inverter forces the DC power to constantly change direction, producing square-wave AC current. However, the square wave AC waveform is not smooth and the voltage keeps changing abruptly, which will seriously affect the life of the appliance.

Therefore, the inverter converts DC power into AC power by speeding up the transmission speed and forming a sinusoidal current output by sinusoidal pulse width modulation(PWM) or maximum power point tracking (MPPT), thereby allowing the square wave AC current to successfully become sinusoidal AC current.

 

Why do you need an inverter?

DC electricity has major limitations in daily applications, for example, AC loads of household appliances cannot be powered by DC electricity, and long-distance transportation will lose most of the power. Therefore, for PV power generation to be widely used in our daily life, an inverter that can turn the DC current it generates into AC current is indispensable.

The inverter can not only convert DC and AC power, but also has the function of maximizing the function of the solar cell, as well as both system modulation and maintenance functions, maximum power tracking and control functions, anti-alone operation functions, active voltage adjustment functions, DC detection functions, DC grounding detection functions, etc.

 

What size of inverter do you need?

The inverter is the part that needs to be chosen most carefully. We need to calculate the rated power of the household appliances used at the same time and consider the situation where the appliances are all staggered, and when used at the same time the power required by the appliances at the beginning of the start is the peak power, much larger than the rated power. For example, air conditioners, refrigerators, washing machines, induction cookers, microwave ovens, etc.

For example, if the total power of the load is 1600 watts, it is recommended to use an inverter of 3000 watts or more. Because, the peak power will affect the inverter output and energy storage.The actual carrying power of the inverter is also a big issue, which often requires the selection of a quality inverter. Many of the poor inverters have a nominal power much less than the actual carrying power.