High Frequency vs Low Frequency Inverter: Which Has Higher MPPT PV Voltage?

Why is the maximum PV input of the mppt of high-frequency inverter higher than the maximum PV input of the mppt of low-frequency inverter?

For high-frequency inverter used in general households, its maximum PV input reaches 500vdc, and we can connect 7 or even 9 580w-720w solar panels in series. While the maximum PV voltage of the built-in mppt of low-frequency inverter is only 120-180vdc. Each group of PV panels can only connect 1-3 580-720w PV panels in series at most. Why is the data of the built-in mppt of low-frequency inverter not as good as the mppt of high-frequency inverter?

Let's take 48V 100A mppt as an example:

The maximum PV input of the high-frequency inverter is: 500vdc, and the total input power is about 6000w;

The maximum PV input of the low-frequency inverter is: 180vdc, and the total input power is about 5,600w. The two are similar, but the readers have noticed that the maximum PV voltage input of the high-frequency inverter is much higher than the maximum PV voltage input of the low-frequency inverter. So if I tell you this:

The built-in mppt of the high-frequency inverter, the maximum PV current input of the 100A mppt is only 25-27amp, and it cannot support expansion, while the built-in mppt of the low-frequency inverter, the maximum PV current input is exactly 100A, which is the same as the amp number of the mppt marked on it, then how do you consider the above problem?

Let's use the physical formula: watt=voltage*amp(current) to explore this problem.

The MPPT built into the high-frequency inverter assumes that the maximum number of PV panels are connected in series (in order to obtain the maximum PV input power), and the maximum PV input current is: 6000w/500vdc=12amp; according to the safety algorithm, the maximum PV current input allowed by its MPPT should be at least 1.5 times of 12vdc, so it should be designed to be at least 18amp. The MPPT built into the high-frequency inverter of Xindun Power takes into account that customers may have two sets of solar panels installed in parallel, so the maximum PV input allowed is directly set to 25-27A, giving customers enough PV current input space. But please note that this 25-27A is only the maximum PV current allowed by the MPPT, not the maximum PV current that the PV panel can really generate.

Then the current that can be converted into the battery charging current is: the actual PV input total power/48vdc = the actual battery charging current amp. Because of the limitation of the maximum PV input current of the above-mentioned mppt, the maximum current for charging the battery is definitely lower than the charging current of the built-in mppt of the low-frequency inverter. We will compare it with the maximum input PV current of the low-frequency inverter later.

First of all, the original intention of the built-in mppt of the high-frequency inverter is to save the cost of other installation consumables for customers. For example, if you want to save 4MM2 PV lines, then the more PV panels are connected in series, even without parallel PV panels, it is the most cost-effective. This is the benefit of the high-frequency inverter designing the maximum PV voltage input to 500vdc.

The disadvantages are also obvious. In the Middle East, Africa and other regions, the climate is hot. Although there are 7-9 PV panels in series, as the temperature rises, the total series voltage generated by the PV panels will also decrease, and the maximum PV current input is also limited: 25-27amp maximum PV current input (for the built-in mppt of 100A 48v). Therefore, if you use a high-frequency inverter for PV charging, it is recommended to connect as many PV panels in series as possible to obtain the maximum PV input power.

The built-in MPPT of the low-frequency inverter: 5,600W/180VDC=31AMP is obviously higher than the maximum PV input current of the built-in MPPT of the high-frequency inverter, almost 3 times, and the important point is: the above built-in MPPT has no limit on the maximum PV input current.

And, benefiting from the fact that the maximum PV input voltage is not high, the maximum charging current for charging the battery is: 5,600W/48VDC/parameter 1.167=100AMP;

It is well known that the greater the current charged with the battery, the shorter the time it takes to fully charge the battery. Therefore, although the built-in MPPT of the low-frequency inverter allows a maximum PV input voltage of only 180VDC and can only connect 2-3 580-720W PV panels in series, after you connect multiple groups of PV panels in parallel, you can get a maximum PV input current higher than the built-in MPPT of the high-frequency inverter.

Therefore, under the same circumstances, the built-in mppt of the low-frequency inverter can charge the battery faster than the built-in mppt of the high-frequency inverter.

However, the disadvantages are also obvious. Users need to buy one or more junction boxes and use more 4MM2 PV lines. The installation cost is increased.

There is no best built-in mppt, only the built-in mppt that suits you. This is Xindun suggestion to the readers. However, we can give the most suitable solution according to the actual situation of the readers. Xindun Power are not only a Chinese manufacturer that sells products, but also a professional company that cares about user experience and is committed to providing users with the most suitable PV solutions.

In the 20 years since Xindun Power was founded, we have provided countless PV system solutions to users around the world, and let users know clearly why they buy Xindun Power products, how to use them after buying them, and most importantly, what benefits they can bring to themselves. This is why there are always repeat customers looking for us.

Xindun Power will be online at any time to provide the most suitable PV solutions for the readers.

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