Defining the nature of progress is a never-ending debate.

Some, like Ray “Mature Male Seeking Singularity” Kurzweil, believe that progress is an accelerating, logarithmic constant.

Others see stair-step progressions with highlights like the 19th century followed by CB radio. Some map progress to network effects: create the printing press, bake 250 years and experience the Enlightenment.

Personally, I think technology -- and particularly, the technology business -- follows the Cambrian model. The Cambrian Period, which began 543 million years ago and ended 490 million years ago, saw an explosion of new, complex life forms: trilobites, algae, worms with fins, hard-shelled creatures, proto-vertebrates, and more.

Then advancing glaciers and oxygen depletion wiped most of them out. All modern animals descended from Cambrian species, but the most direct descendants of the era -- hagfish, sponges -- aren’t exactly the glamor boys at the zoo.

Examine any segment of high tech and you’ll see the same flowering of ideas. Commodore Sinclair and a few others popularized PCs in the early '80s. Soon, a multitude of brands -- MicroBee,  Atari, AST, V-Tech, Fujitsu-Siemens, Alaska -- emerged.

Only a few -- Apple, Dell, Compaq -- have survived in the long haul. You can’t berate the fossils: many contributed to the species. Osbourne came up with the idea for the laptop. Packard Bell honed retail.

The number of promising Linux startups went from 57 to three at the tail end of the internet boom. I actually even met a guy who was a billionaire for about 17 minutes through a Linux IPO.

We’re in the midst of one of these cycles in solar electronics. A few years ago, Enphase Energy began to tout the microinverter as a way to maximize output from residential and small commercial systems. Microinverters had been debated before, but reliability and cost had held back the concept.

Accelerating sales, however, changed the debate -- more than 500,000 Enphase microinverters have been installed to date -- and have inspired variations on the theme.

New types of microinverters (with longer warranties) from companies like SolarBridge Technologies followed. National Semiconductor and Tigo touted DC maximizers, which aim to achieve the same sort of improved energy harvesting made possible with microinverters. DC maximizers, however, are coupled with standard centralized inverters, which they claim will lower costs. Enphase, SolarBridge, Tigo and others will discuss these trends at the Solar Summit 2011 takinkg place March 14 and 15 in Palm Springs.)

Petra Solar and Sunverge, meanwhile, have combined voltage management and other smart grid functionality to give utilities a twofer -- solar and voltage control -- through electronics. Utilities benefit more than consumers with this twist on the theme. Yesterday, Transphorm revealed gallium nitride AC-DC converters, which could increase the output of inverters and ultimately drive down the cost per watt of solar.

Lately, we’ve seen the emergence of hybrids. Apparent Energy, created by alumni from the wind industry, have come up with a microinverter that combines some of the functionality of DC maximizers and power storage devices. Bill Vogel, the ex-CEO of Trilliant, is involved.

“It produces reactive power on demand,” said CEO Peter Gish. “It looks like spinning capacity.”

HiQ Solar says it has come up with a new class of inverter it calls the mini-inverter. Basically, the company attaches a DC-to-DC converter to four panels and then connects an array of four of its DC-to-DC modules to a medium-sized inverter.

Ideally, the system will let power producers squeeze more juice out of each panel, but with fewer inverters and no electrolytic capacitors, the component that can fail first in a microinverter.

HiQ’s does module and maintenance monitoring via the web too, but, in a twist, won’t charge for it.

“You shouldn’t have to pay someone for your data,” said CEO Andre Willis. Free: it’s a proven way to gain market share.

 And meet Bert Wank, CEO of InfiniRel, which wants to exploit digital signal processors (DSPs) to interpret power signals coming off panels to manage the output and improve safety.  DSPs effectively allow cell phones to work. Texas Instruments is the dominant manufacturer and naturally, Wank and the rest of the team hail from TI.

Clarian Power has something it calls a SmartBox to store and control energy. Other names: TenKSolar, SunSil, Array Converter, Ivoloar (“I’d like to buy a vowel please, Pat”), and Azuray.

Who will win? Who knows? The point is we’re going to see a dizzying level of experimentation before we see a formula that’s magically delicious.

Some of the pain points are already clear: how can the number of electrolytic capacitors in microinverters, a chronic point of problems, be reduced? What architecture will minimize the number of required components? What should be integrated into a panel and what needs to be kept in a separate unit?

Do existing components do the trick or do you need to design your own chips, like Petra?

Just as important, what do installers want? And what do panel makers see as a threat? Technology, business strategy and channel concerns will ultimately hone the field to a few winners.

You will know the cycle is complete when some analyst claims the outcome was obvious all along. It was so obvious he just didn’t think it needed stating a year ago when everyone was confused.

The consolidation phase is the dreadful side of the cycle. But until then, it’s going to be quite interesting.