What are DC optimisers and what do they do?

What are DC Power Optimisers and what do they do?

Whether you already have a solar panel system, or if you are contemplating installing a new one, DC Power Optimisers play a vital role in maximising the performance of a DC solar power system. However, unless you are an electrician, engineer or have done a fair amount of research (or Googling), you may be unfamiliar with what they are and how they work.  

Solar panels generate electricity by converting the sun’s energy into direct current (or DC energy). A solar inverter then converts that into the alternating current (AC energy) that is used in our homes.  DC Power Optimisers are a type of Module-Level Power Electronics (MLPE), which means they are a component that is fitted at module, or panel level.  Put simply, wiring DC Power Optimisers to each panel helps deliver more power by turning them into “smart” panels. Typically, these are installed into a solar panel system, new or existing, to maximise performance. 

DC Power Optimisers are seen as a hybrid between conventional DC string inverters and microinverters. You will still have a DC String Inverter easily mounted on the wall, but the system is also equipped with individual Power Optimisers on each panel. For a typical 6.6kw system, you can have 20 panels and 20 DC Power Optimisers constantly tracking the maximum power point (MPPT) of each panel individually. 

Importantly, DC optimised systems automatically cut energy to a touch-safe DC voltage in the event of damage or a fault, helping to prevent fires and electrocution. This means that they can not only generate more energy from each panel, but the panels can also regulate the output of solar panels to avoid high voltage DC in the system, reducing the fire risk. And yes, we did just use the term ‘fire risk’ not to be alarmist, but because we believe everyone should have access to all the facts in order to make an informed decision. While solar panel systems are generally safe, conventional DC systems generate DC power in an array of modules, accumulating potentially dangerous high-voltage DC. In the event of a fault or damage to the panels, string inverter or cables, this can result in a fire. 

What are the benefits of DC Power Optimisers?

In a conventional PV system, solar panels are wired together in a string, and the performance of the whole system is determined by the weakest panel in that string. If one of the panels is underperforming, which can happen for a number of reasons (such as cloud cover, dirt, soiling, etc), all of the panels on that string will also underperform. 

Unlike conventional DC systems, an array of solar panels installed with DC Power Optimisers do not suffer from the same system power degradation in the event of a single panel fault or failure. With DC Optimisers, each panel can operate independently, so one rotten apple doesn’t spoil the whole barrel. This allows the energy production in each module within the array to be maximised, reducing potential power losses due to ageing, soiling, shading, obstructions or faults within a panel. All of these can make a significant impact on the power a system can generate over time, helping to maximise your return on investment. 

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Solar panel systems fitted with smart energy solutions such as SolarEdge’s world leading DC Power Optimisers, benefit from more flexible arrangements, such as multiple tilts, orientations and types in a single string.  In conventional DC systems, you are restricted with two, sometimes three directions per inverter. The flexibility that comes with DC Power Optimisers enables you to position your panels to maximise the time in the sun and generate more power for your home. 

Putting Safety First

Even when a solar panel system is disconnected, panels can still produce energy when the sun is up. One important benefit of DC Power Optimisers is that they have an added built-in safety feature that automatically reduces DC voltage to touch-safe levels. This can happen if a system is disconnected from the grid, such as when grid power is shutdown, the inverter is turned off or a cabling fault it detected. The extra layer of safety protects the integrity of the PV system and prevents fires and electrocution while providing protection to people and property. 

Do all installers use DC Optimisers?

Most experienced solar installers in Australia are aware of safer solar technologies such as DC Power Optimisers. SolarEdge is renowned for their DC Optimisers and are generally the go to solution within the Australian market. 

It is tempting to be attracted by the initial purchase savings promised by conventional DC solar systems, but the choice could ultimately come in a way that can cost you in the long run. Whatever you decide, make sure you make an educated decision. Pick wisely and your investment will work hard for the environment as well as reduce your energy bills, protect your property and keep your loved ones safe.

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