ARDA DC Microgrid Platform

Components: Energy Storage, Loads, Sources, Power Converters

Using the ARDA DC Microgrid Platform customers can integrate a wide range of Components on to a microgrid on a “plug and play” basis using third party modular Power Converters.
The commands are then communicated to these Components using distributed ARDA Virtual Master Controller  and ARDA Response Controllers .

Energy Storage
Energy Storage system plays a central Management role in the ARDA DC Microgrid Platform simultaneously acting as both the Power and the Energy Manager.
One Platform - multiple Technologies
The Platform is battery technology agnostic, and can host flow, Li-ion and lead acid batteries.

Flow batteries in particular have characteristics that are very attractive to microgrids such as deep discharge capability, long life cycle, fast response, decoupled power and energy ratings, and no cell to cell equalization needs. 
One Microgrid - multiple Batteries
A single Microgrid can accommodate multiple batteries and technologies.

​This feature could enable complex Microgrids that match multiple battery technologies to the functions they best serve.
PLUG-and-PLAY
The Platform's proprietary Controls allow customers to easily scale, add or remove energy storage capacity. 

Battery Converters

Energy Storage connects to the bi-polar DC bus via ARDA Battery DC-DC Converters, which include embedded ARDA Virtual Master Controllers, at
​
760VDC (+/- 380VDC).

​click to go to
ARDA Battery DC-DC Converter

Sources
A DC microgrid is great for DC Sources and the ARDA DC Microgrid Platform is no exception. But that’s not all, many distributed sources of “AC” energy  will benefit significantly when linked to a DC microgrid.
The ARDA DC Microgrid Platform promotes modularity in sizing components including Sources, but can also accommodate non-modular approach too.
DC Sources ("Genuine")
The most important “Genuine” DC Source is Solar PV. In many parts of the world, including in the United States, Solar PV already represents a majority of newly installed energy capacity.

Currently, the majority of Solar PV installations feed the grid rather than local loads.

​However, PV Solar's brighter future is in distributed generation. In addition to the evolving economics of distributed PV, a significant contributor to this transformation is the emergence of new Microgrid technologies that accommodate local consumption of PV generated power.
​Another “Genuine” DC Source is Fuel Cells. As the cost of Fuel Cells decline they may play an important role in distributed generation by serving as a baseload source for microgrids.

​ARDA Power has produced Source DC-DC Converters optimized for both Solar PV and Fuel Cells.
AC Sources ("DC upgradable")
Many native AC generation sources would work more efficiently and have their mechanical controls simplified if operated at variable AC frequency/voltage enabling variable RPM optimized for load conditions. Some diesel and gas generators, microturbines and co-generation units already employ these technologies.

But the variable AC frequency and voltage technologies come at a cost, since they basically require adding two power converters: AC-DC to establish an internal DC bus and DC-AC to re-establish an "interface" with the local AC network.

Connecting these high efficiency AC sources to a DC microgrid eliminates the requirement for one (DC-AC) of the two converters. This reduces cost, increases efficiency and improves reliability, thus, accelerating adoption of these high efficiency AC sources. 
AC Sources ("Regular")
AC Sources that don't utilize high efficiency technologies can still be connected to the ARDA DC Microgrid Platform via ARDA or third-party converters.
PLUG-and-PLAY
The Platform's proprietary Controls allow customers to easily scale, add or remove energy generation capacity. ​

Source Converters

Sources connect to the bi-polar DC bus using third-party converters that output power at
760VDC (+/- 380VDC).

​ARDA Response Controllers are used with third-party converters.

For Solar PV the Source Converters used to connect to the DC bus are capable of managing the maximum power point tracking (MPPT).

It is important in a DC Microgrid application that the Solar Source Converters are able to isolate or significantly reduce ground faults to the DC bus, either with:

- isolated converters (the most resilient and maintenance friendly approach)
- non-isolated converters with ground fault limitation

Loads
The ARDA DC Microgrid Platform is by definition friendly to DC Loads. In addition, many AC Loads are actually “Camouflaged” DC Loads that will benefit significantly when linked to an ARDA DC Microgrid.
DC Loads including the "Camouflaged" ones are now burdened with additional costs, extra efficiency losses and reliability issues when connected to traditional AC networks.

​This is becoming more critical as DC Loads become more pervasive due to falling costs. This trend is also getting a major boost from global standardization effort thanks to organizations like IEEE and the EMerge Alliance.
DC Loads ("Genuine")
“Genuine” DC Loads are devices that run naturally on DC. A majority of these Loads use the 12/24/48VDC standard, or the globally emerging 380VDC standard, while certain higher power Loads run on voltages exceeding 700VDC.

Examples include: LED lights, EV chargers, computers, servers, etc.  LED lights may look like “Camouflaged” DC Loads since frequently they are manufactured to connect to AC networks using DC-AC converters.

Nowadays, these “Genuine” DC Loads connect to:
  • traditional AC distribution networks via embedded or separate DC-AC converters, or
  • emerging DC distribution networks directly on the DC bus or via embedded or separate DC-DC converters.
DC Loads ("Camouflaged")
"Camouflaged" DC Loads include modern high efficiency AC Loads that employ variable speed drives (“VFD”), which are fed from an internal DC bus.  These high efficiency Loads, including for example certain HVAC systems, must then use a DC-AC converter "interface" to the local AC network.

There is a big opportunity to dramatically improve efficiency by linking these “Camouflaged” DC Sources directly to the ARDA DC Microgrid Platform, eliminating an unnecessary DC-AC “interface" and thereby reducing capital costs while improving efficiency and reliability.

​VFD based loads currently offered on the market have a wide range of internal DC bus voltages, but many of them are close to either 380VD or to 760VDC.
AC powered Motor Drive with a Rectifier front end
AC powered Motor Drive with a Rectifier front end
 AC Loads
For the foreseeable future DC Microgrids will not only have to accommodate regular AC loads, but will often co-exist on the same site or in the same building with traditional local AC distribution networks.

If there is a requirement to have select AC Loads operate during AC Grid faults or outages, or in the case of Off Grid applications, the base option is to connect these loads to the ARDA DC Microgrid Platform via dedicated DC-AC inverters.
PLUG-and-PLAY
The Platform's proprietary Controls allow customers to easily scale, add or remove Loads. 

Load Converters

Both "Genuine" and "Camouflaged" DC Loads can be connected directly to the DC bus at

760VDC (+/- 380VDC)

DC Loads with the lower voltages connect to the DC bus via off-the-shelf down (buck) DC-DC Converters.

​AC Loads connect to the DC bus by third-party DC-AC inverters.

​Add-on ARDA Response Controllers are available as required.

AC Grid
In the ARDA DC Microgrid Platform, the AC Grid and its interfacing grid tie DC-AC inverter play NO Management role. Instead the AC Grid is simply a bidirectional device that can operate as a Source or a Load on our Platform.
The DC Microgrid removes the requirement to follow frequency and phase angles and eliminates reactive power flows making operation of a microgrid much simpler.
The simplified role of the AC Grid and grid-tied inverter makes it easier for the ARDA DC Microgrid to interact with the AC Grid not only  in the export and import of energy, but also in the provision of ancillary services.
PLUG-and-PLAY
The Platform's proprietary Controls allow customers to easily scale, add or remove AC Grid's energy import/export capacity for the Microgrid. ​

Grid tie Converters

​The ARDA DC Microgrid connects to the grid using third-party grid tie DC-AC converters with a fixed (narrow range) DC input voltage at:

760VDC (+/- 380VDC).

The ARDA Microgrid Platform's DC-AC converters are simple and low cost: 
- No Microgrid Management role
- Converter Sizing dictated by Export/Import needs not Microgrid size
- Converter DC input voltage has a fixed (narrow range) DC input voltage

Add-on ARDA Response Controllers come with the DC-AC converters.​
no bulky and expensive
solid state ​static transfer switches