Energy Optimization

Current PV inverter systems are optimized for peak power efficiency. This maximizes utility and government subsidies, but does not optimize total energy saving per dollar of installed system cost. The Total Energy Company system is designed to bring a wide variety of system efficiency improvements in both energy harvesting and consumption not supported in current inverter systems.

Some of the additional system benefits of the Total Energy Company inverter system are...

• Grid-tied, Grid-independence
  Full operation to local loads during grid failures without batteries
  Separate AC interface for local loads and grid
  Ability to deliver reactive/surge power to local loads
• Lower Voltage, Parallel PV Array
  Modularized low voltage PV array reduces engineering and installation costs
  Less sensitive to partial shading than high voltage string arrays

Parallel Wiring for PV arrays

If PV modules are wired in series, poor performance in one module will affect the output of the entire string.  Think of a string of Christmas lights. With the old version when one bulb fails, all the lights go out.  The new strings you buy today continue to function when one bulb fails.  What is the difference between the old design and the new one?  It is how they connect the bulbs to the power cable.  The old version had all the bulbs wired in series.  That is, the wire from one bulb was connected to the next bulb and so on until the last bulb connected back to the ac plug.  The new design has all the bulbs wired in parallel.  That is, each bulb is connected between the two ac wires that make up the cable.  Well, the case for connecting all the solar panels in a series is not as bad, but when one panel is not functioning properly, the entire string of solar panels’ output decreases by as much as 20%.  There is a way of avoiding such large a loss.

The solution is simple: wire them in parallel. Instead of having 20 PV modules wired in series, have all the panel outputs connected in parallel by individually connecting each panel to the inverter. This maximizes the power output from the solar array, and eliminates losses due to a solar panel not functioning properly.  For example, if one of the panels connected in parallel fails, the loss of the power delivered by the array would be limited to a maximum of only 5%.

The problem with this solution is that parallel wiring produces lower voltages at higher currents delivered to the inverter.  Then one needs an inverter able to deal with these higher currents and lower voltages without a loss in inverter efficiency.

Total Energy Company technology is designed for parallel operation and is extraordinarily efficient with a 96% solar array power throughput.  That is, 96% of the solar power entering the Total Energy Company unit is delivered to the user even with the solar power entering the Total Energy Company unit varying from 100% to as low as 20%.  From 20% of rated power (efficiency is >97) to as low as 10%, the efficiency remains above 90%.

• Universal Distributed Generation Inverter
  Same inverter system supports battery, wind, fuel cell, geothermal, tidal and other sources
• Enables Energy Management Systems
  400vDC for high efficiency variable speed DC motors in air conditioning and heat pumps
  48vDC for high efficiency DC lighting
  Enables cost optimization of power storage and release for time-of-day cost metering

The Solar Energy Grid Integration Systems (SEGIS) is a US Department of Energy (DOE) directed effort to maximize the value of PV systems to owners, utilities and governments. This is accomplished with energy management systems enabled by the Total Energy Company inverter system SEGIS Concept Paper 372KB pdf