Turbocharger with electrically coupled fully variable turbo-compound capability and method of controlling the same

A turbocharger apparatus of an internal combustion engine comprising:

• a turbine mounted on a turbine shaft;
• a compressor mounted on a compressor shaft;
• a first electric machine rotatably coupled to the internal combustion engine that generates electricity in an electricity generating state where electricity flows from said first electric machine and that adds rotational power to the internal combustion engine in an electricity consuming state where electricity flows to said first electric machine;
• a second electric machine electrically connected to said first electric machine, said second electric machine having a rotating shaft that is rotatably coupled to at least one of said turbine and said compressor that generates electricity in an electricity generating state where electricity flows from said second electric machine and that rotationally drives at least one of said turbine and said compressor in an electricity consuming state where electricity flows to said second electric machine;
• a planetary gearset;
• wherein said planetary gearset further includes:
• a sun gear rotatably coupled to said turbine shaft;
• at least one planet gear rotatably coupled to said compressor shaft;
• and
• a ring gear rotatably coupled to said rotating shaft of said second electric machine;
• wherein said planetary gearset varies rotational speeds of said turbine shaft, said compressor shaft, and said rotating shaft of said second electric machine with respect to one another in response to electricity flow to and from said second electric machine in order to maximize efficiency and power of the internal combustion engine;
• an auxiliary gear rotatably coupled to and carried on said rotating shaft of said electric machine;
• and
• a transfer gear rotatably coupled to and extending from said ring gear that is meshingly engaged with said auxiliary gear such that said auxiliary gear and said transfer gear rotatably couple said ring gear and said electric machine.

A method of controlling a turbocharger apparatus having a turbine, a compressor, a planetary gearset having a sun gear, at least one planet gear, and a ring gear, a first electric machine, a second electric machine, an auxiliary gear rotatably coupled to and carried on a rotating shaft of said second electric machine, and a transfer gear rotatably coupled to and extending from said ring gear being meshingly engaged with said auxiliary gear such that said auxiliary gear and said transfer gear rotatably couple said ring gear and said second electric machine,

• the method comprising the steps of:
• driving the turbine with exhaust gas flow from an internal combustion engine, the turbine generating mechanical power in response to being driven by the exhaust gas flow;
• transferring all of the mechanical power generated by the turbine through the planetary gearset to the compressor during a first operating mode where only the turbine drives the compressor;
• driving the first electric machine with the internal combustion engine, the first electric machine generating electricity in response to being driven by the internal combustion engine;
• supplying the electricity generated by the first electric machine to the second electric machine to drive the second electric machine;
• and
• transferring the mechanical power produced by the turbine and the second electric machine through the planetary gearset to the compressor during a second operating mode where both the turbine and the second electric machine drive the compressor.