Low-loss zero current switching shunt regulator for AC alternator

A combined alternator and control circuit comprising:

• an alternator for generating AC current, a plurality of outlet lines leading from the alternator, and each for receiving a phase of current generated by the alternator, and passing said phase downstream toward a system load;
• tap lines associated with each of said output lines, said tap lines each being associated with a switch, and a current sense for sensing a current in each of said tap lines, and sending a current signal for each of said tap lines;
• said switches being operable to drain power to a drain when in a first state, and to allow the power to pass downstream to a system load when in a second state;
• a switch control for controlling the switches to change between the first and second state;
• and
• a detector for detecting when each said current signal is approaching a zero crossing between a positive portion and a negative portion, and said switch control being operable to take in the information with regard to the approaching zero crossing, and change one of the switches associated with a particular tap line having the current signal approaching the zero crossing, between the first and second states.

A control circuit for use with an AC alternator comprising:

• a plurality of outlet lines leading from the alternator, and for each receiving a phase of current generated by the alternator;
• tap lines associated with each of said outlet lines, said tap lines each being associated with a switch, and a current sense for sensing a current and sending a current signal;
• said switches being operable to drain power to a drain when in a first state, and to allow the power to pass downstream to a system load as needed when in a second state;
• a switch control for controlling the switches to change between the first and second state;
• a detector for detecting when the current signal is approaching a zero crossing between a positive portion and a negative portion, and said switch control being operable to take in the information with regard to the approaching zero crossing, and change the switches between the first and second states;
• and
• an output voltage is detected downstream of said tap lines, and is fed back to the switch circuit, said switch circuit providing additional control to maintain said output voltage below a predetermined limit, and being operable to drain both portions of said current signal to reduce the output voltage should the output voltage be greater than the predetermined limit.