GTM Research forecasts a $6.9 billion PV inverter market for 2011 and MJ Shiao, GTM's inverter expert, just published the authoritative report on the Global PV Inverter Landscape.

The sub-sector of inverters, microinverters and their kin -- dubbed "distributed inversion and optimization" -- is a small, innovative and growing segment of the market, and Shiao explores it comprehensively in his report.

We've covered the potential benefits of distributed electronics at length in our solar coverage at Greentech Media. There are potential energy harvest gains, potential improvements in design flexibility, and potential reliability gains. There is some question as to whether the microinverter solution or the DC-to-DC power optimizer architecture is the way to go.

Intersolar Europe is officially underway this week and there's the usual flood of announcements coming from the conference. Here's a roundup of news in the microinverter and distributed electronics sector to keep our readership on top of this important and emerging piece of the solar installation puzzle.

Array Converter is still in stealth. Read about them here and peruse their patents here. Make sure to check out this comment thread here.

Azuray is displaying their power-optimizer/junction box and communications gateway in partnership with Renhe Photovoltaic Technology, a large China-based PV junction box manufacturer. 

Direct Grid's micro-inverters for large commercial and utility-scale projects use Echelon Corporation's energy control networking software. 

eIQ Energy signed an agreement with Granite Construction (NYSE: GVA) to provide parallel solar technology for a 1.2-megawatt solar PV installation at Granite's aggregate and hot mix facility in Coalinga, California.

Enecsys won $41 million in round B VC funding from Climate Change Capital Private Equity, Wellington Partners, NES Partners, and Good Energies last month. Each Enecsys micro inverter has a built-in ZigBee wireless monitoring system.

Enphase has hit the 750,000-unit mark on microinverter shipments. At this pace, the one-million-unit threshold is only a few months away. The firm also launched its most efficient microinverter (96 percent CEC-weighted), along with a 25-­year limited warranty.

Involar builds microinverters in China that look a lot like Enphase microinverters, on the outside at least.

National Semiconductor's integrated circuits are designed for use in PV system microinverters, power optimizers, and charge controllers.

Petra Solar is going global with their pole-mounted AC module.

Phobos Energy has a license agreement with Colorado University for PV balance-of-system technology developed at CU-Boulder's Colorado Power Electronics Center. 

Power-One (Nasdaq:PWER), the world's second largest central PV inverter firm, announced the launch of a new 300-watt microinverter as well as a DC/DC power optimizer -- marking the first entry in the distributed electronics space of an established central inverter player.  

SolarBridge started production of their microinverter with Celestica in Dongguan, China and added some strength to its board. The firm will be making some new partner announcements this week. In a conversation with the CEO, Ron Van Dell, he stressed that SolarBridge's technology is not really a microinverter; it's an AC module (ACM). The firm is not selling the microinverter by itself but rather is engaging in strategic partnering. The CEO cited the bankability of an ACM from SolarBridge and an established module maker.

SolarEdge, a provider of solar power optimization systems, and Cleaner Air Solutions, one of the largest solar PV system providers in the U.K., announced a distribution partnership. In the first quarter of 2011, Cleaner Air Solutions ordered 3 megawatts of SolarEdge power optimizers and inverters. SolarEdge also announced a partnership with Flextronics to manufacture in Ontario to qualify for the Ontario FIT's local content requirements.   

SMA, the world's largest manufacturer of central inverters, is due to introduce a microinverter in the next six months, according to widely circulated but unsubstantiated rumors.

Sparq Systems' microinverters will be constructed by Sanmina (Nasdaq:SANM).

TenKsolar combines reflectors and sub-module cell-level MPPT

Tigo has UPSolar, Canadian Solar, Schott and Jinko displaying products in their booth at Intersolar Munich. The firm is collaborating with Shoals Technologies to put the Tigo Energy Module Maximizer in a Multi-Link J-box for more rapid integrated product adoption. Tigo recently closed a $10 million venture funding round.

The big U.S. residential solar installers, solar leasing, and residential PPA companies are not entirely comfortable with the new breed of distributed electronics, be they microinverters or DC-to-DC approaches. The hundreds of thousands of microinverters shipped by Enphase and tens of thousands of units shipped by Tigo and SolarEdge have gone through smaller installers in the long tail. That could change soon.  Note that the market share for smaller installers is gaining at the expense of the larger firms.

All of these technology solutions seek to maximize energy harvest, minimize power attenuation from shading and panel or thermal mismatch, and improve on the reliability and efficiency of central solar inverters, the long-dominant technology.

Residential solar inverters have a cost of about $0.45 per watt, while utility inverters are in the range of $0.26 per watt. There is ongoing pressure to drive those costs down while maintaining performance and reliability. The DOE's Steve Chu wants to see inverters at $0.10 per watt.