Integrel power
What is it? A turbo alternator which can produce 9kw electrical power off your engine, replacing the need for a generator
Tthis brilliant new system can produce enough power for an average cruising yacht to have three to four days’ silent running at anchor. Who better to explain it than marine electronics guru Nigel Calder, who has been deeply involved in its development.
Here he outlines how it works:
The theory
The nature of engine power curves and the way propellers work is such that when a boat is under way the propeller does not absorb all the available power until the engine is running at full speed. What’s more, up until close to full speed the propeller load is less than what is required to operate the engine at peak efficiency: adding load improves efficiency.
The Integrel system uses the surplus power to generate electrical energy; the generating load is carefully managed to optimise engine fuel efficiency. One engine serves two purposes – propulsion and electrical generation – with efficiency improvements in both.
The implementation
The Integrel generating device is effectively an alternator on steroids. It looks like a conventional alternator but through the addition of embedded permanent magnets it achieves much higher levels of output with much greater efficiency than even high output alternators.
It has just one moving part, the rotor. And just like an alternator, it can be run at any speed as opposed to the fixed speed required for most standalone generators. This variable speed capability is critical in terms of optimising performance and efficiency.
The output of a conventional alternator is converted to direct current for charging batteries via diodes mounted in the back of the alternator. These diodes create unwanted heat and absorb energy. The Integrel system removes the diode pack and replaces it with a more effective external device.
The Integrel generator is controlled via a field circuit, much the same as a conventional alternator, except that far less field current is needed for a given output. This reduces parasitic losses. The controller creates a nominal engine fuel efficiency map and manages the electrical load to optimise fuel efficiency up until batteries are almost fully charged, at which point the controller reverts to a conventional management algorithm based on battery state of charge. To avoid overloading the engine, the controller ramps down output when approaching idle speed and full speed, and when manoeuvring in harbour.
The result
Under way, the Integrel system achieves efficiencies far above the average of stand-alone generators (in many applications, five to ten times more), while achieving modest gains in propulsion efficiency. In the event the propulsion engine has to be run at anchor for generating purposes, the Integrel system operates as a variable speed generator. It applies sufficient load to achieve fuel efficiencies comparable with the peak efficiencies of stand-alone generators and well above the average of these generators – and far above those of a cruising boat battery charging at anchor with conventional alternators.
The high levels (up to 9kw) of output considerably reduce engine run times.
Final thoughts
The combination of permanent magnet technology, the ever reducing cost of electronics, and the sophistication of modern software tools has resulted in a game-changing breakthrough. The Integrel system supplies the electrical energy necessary for modern onboard lifestyles with improved efficiency and less engine run time. It makes most stand-alone generators, with their associated installation and maintenance requirements, obsolete.
What’s not to like about that?
‘THE INTEGREL GENERATING DEVICE IS LIKE AN ALTERNATOR ON STEROIDS’