Showing posts with label hybrid inverter. Show all posts
Showing posts with label hybrid inverter. Show all posts

Sunday, April 18, 2021

How to Choose the Right Solar Inverter for Your Solar Power System (Part 2)

0 comments

inverter solar power system
Photo by William Mead from Pexels

There are three types off-grid (also known as stand-alone) solar inverters according to the output waveform of the voltage – pure sine wave, quasi (modified) sine wave, and square wave. 

Pure sine wave inverter has the output waveform of the voltage like a sine wave and this form of electrical output is the same as you will find coming from the utility grid. Modified sin wave inverter has the output waveform not exactly sine wave but it resembles the shape of a sine wave.

Pure sine wave inverter has many advantages over modified sine wave inverter. Pure sin wave inverters can run all electrical home appliances effectively. They are necessary for sophisticated electronics, like a fancy new television or gaming console, fluorescent lights and dimmers, inductive loads like microwave ovens. Pure sine wave inverter keeps appliances safe and more durable. 

Modified sine wave inverter is inexpensive but has a serious disadvantage: it is not compatible with all appliances and may create excessive heat in appliances which will reduce their lifetime. Also, modified sine wave inverters create more noise and a high electrical surge can lead to malfunctioning of home appliances. Modified sine wave inverter is suitable for simple systems or a DIY emergency solar kit, or a cabin with modest electrical needs. They work best with older TVs, incandescent lights, motors with brushes. Generally, they are not good with modern electronics, audio, induction motors, rechargeable batteries, or digital clocks.

The square wave inverter has the output waveform of the voltage like a square wave. This type of inverter is least used among all other types of inverter because all appliances are designed for sine wave supply. If we supply square wave to sine wave-based appliance, it may get damaged or losses are very high. The cost of this inverter is very low but the application is very rare. It can be used in simple tools with a universal motor.

Off-grid inverters are not connected to the electrical utility grid and they are designed to be integrated with a battery bank. The off-grid inverter draws power from the battery and converts it from DC power from the solar panels into AC power. The off-grid battery inverter only discharges the battery (unlike an inverter/charger). When the batteries’ charge level gets below a threshold, the inverter will shut down to protect both home appliances and the batteries.

In an off-grid system, PV panels charge the batteries via a charge controller, and only the power demanded by the loads is inverted to AC. These systems do not have access to the electrical utility grid so it is important to properly size the inverter as well as the battery bank.

The battery inverter/charger combines the functionality of a DC/AC battery inverter and a battery charger. Like any inverter, an inverter/charger converts DC (battery) power into AC power but it will also charge (converting AC into DC energy) the attached batteries when an AC power source is present. Generally, they are designed for applications in which AC power will be available from an outside source, such as a generator or shore power. Besides, in an off-grid solar power system, they are also used in a boat or a RV. 

Some advanced models of inverter/chargers (multi-mode, bi-directional) can charge a battery, converting AC power from the utility grid to DC power, and also feed power back into the grid using net metering, similar to the grid-tie inverters. If there is a power outage, the inverter/charger will automatically switch to battery power to provide power to connected equipment. 

A hybrid solar system is connected to the electrical utility grid and also has a battery bank. Hybrid inverters combine a standard solar inverter and a battery inverter/charger in one simple unit. Hybrid inverters convert the DC power your solar system generates into AC power, which can be used to power your home appliances or fed directly into the grid. The hybrid inverter can also manage inputs simultaneously from the solar panels and a battery bank. The batteries are charged with either solar panels or the electricity grid, depending on which is more economical or preferred.

Not all hybrid inverters provide battery backup in the event of a blackout. A basic hybrid inverter cannot supply power when there is a blackout (commonly known as an uninterruptible power supply or UPS function). There is another type of hybrid inverters so-called multi-mode inverters with backup power capability during a blackout, which are more advanced hybrid inverters designed to work in on-grid mode and off-grid mode for a long time.

A grid-tied solar power system will not power your home during a blackout, so in areas where blackouts and weather-related outages are common, a hybrid solar power system with a multi-mode hybrid inverter may be a solution. You can also buy a hybrid inverter for your grid-tied solar system if you plan to add batteries soon and this is the most cost-effective option. 

The modern hybrid inverters are more versatile than grid-tie and off-grid inverters, and they are also more expensive. The advantage of hybrid solar inverters is that they allow the centralised monitoring of the solar array. Thus, the homeowners only have to check on one portal to understand how much energy their solar panels are producing and how the batteries are performing. 

You can always add storage to an existing grid-tied solar power system later and it is still the common practice as the homeowner already has a grid-tie inverter installed. However, a disadvantage of this method is the higher cost. 

Another option is by adding an AC coupled battery system such as the Tesla Powerwall 2 and Sonnen ECO (they have built-in inverter) to your grid-tied solar system. These battery systems can be retrofitted to a home with an existing solar power system and grid-tie solar inverter. They are expensive but they are also the best in the market.


Friday, May 15, 2020

Hybrid Solar Power System - the Best of Grid-Tied and Off-Grid Systems

0 comments

The hybrid solar power system is a combination of grid-tied and off-grid solar power systems. This system is described also as off-grid solar with utility backup power, or grid-tied solar with battery storage. The hybrid solar power system comes with a special hybrid inverter (sometimes referred to as a multi-mode inverter) that can transmit direct current (DC) power to and from your batteries and provides alternating current (AC) power between the grid and your home when necessary. The hybrid inverter can simultaneously manage inputs from both solar panels and battery storage, charging batteries with either solar electricity or electricity from the grid.

Solar Panels

The hybrid inverter takes advantage of changes in the utility electricity rates throughout the day. You can temporarily store whatever excess electricity your solar panels produce in batteries, and put it on the utility grid when you are paid the most for every kWh. And you can rely upon your battery stored solar electricity while electricity is expensive and switch to the grid when it is cheap. 

The ability to store and use your solar energy when desired is known as self-use or self-consumption. 

In case you have already installed a grid-tied solar panel system you also have a traditional inverter (solar inverter) which converts DC into AC. If you would like to have a hybrid solar power system you should buy battery storage and a separate battery-specific inverter. 

An option is to buy a hybrid inverter for your grid-tied solar panel system if you are planning soon to add battery storage. Thus you won’t need to purchase a separate battery-based inverter. The hybrid inverter can function as both an inverter for electricity from your solar panels and a solar battery. It combines a solar inverter and battery-specific inverter, so it can charge and discharge battery storage. On the other hand, there are some modern energy storage systems, like the Tesla Powerwall 2, which comes with an inverter already built-in, eliminating the need for a hybrid inverter. 

The hybrid solar panel system is configured in such a way that your home uses solar power first, then stored power in the battery, and then grid power. With a solar hybrid system, you are less reliant on the grid and solar battery storage is used as a back up when solar power is not available. When the stored energy is depleted, the grid is there as a backup, allowing consumers to have the best of grid-tied and off-grid solar systems. And the battery storage is discharged less frequently, which extends its life. It needs to be replaced less often and saves you the cost of purchasing a backup generator. 

The hybrid solar power system is at least half the price of an off-grid system but they are more expensive than an on-grid system – typically double the price of the grid-connected solar power system. The hybrid solar power system is also more complicated for installation and takes more space. 

In summary, the hybrid solar power system has the following advantages: 
  • gives you a continuous uninterrupted power supply 
  • stores solar electricity or low-cost electricity 
  • allows using solar power during the peak times of the electricity grid 
  • solar power is available during a blackout or grid outage 
  • reduces the power consumption from the grid 
  • you are not dependent on the weather conditions 
  • gives you more independence than on-grid solar power system