Method for balancing battery pack energy levels

A method for balancing energy levels between a first battery group and a second battery group in a battery pack, said first and second battery groups connected across a first current bus and said first battery group further connected across a second current bus, said method comprising the steps of:

• generating a first state of charge value indicative of a first energy level of said first battery group;
• generating a second state of charge value indicative of a second energy level of said second battery group;
• and,
• controlling said first energy level responsive to said first state of charge value and said second state of charge value,
• wherein said controlling step includes the substep of charging said first battery group to thereby balance said first energy level of said first battery group with said second energy level of said second battery group,
• said substep of charging said first battery group includes the substeps of:
• generating a reference current value responsive to said first and second state of charge values;
• comparing said reference current value to a first current level of a first current provided by said first battery group to said second current bus to thereby obtain a current error value;
• providing a second current to said first battery group responsive to said current error value;
• and,
• wherein said substep of providing a second current includes the substep of controlling a converter responsive to said current error value.

A circuit for balancing energy levels between a first battery group and a second battery group in a battery pack, said first and second battery groups connected across a first current bus and said first battery group further connected across a second current bus, said circuit comprising:

• means for generating a first state of charge value indicative of a first energy level of said first battery group;
• means for generating a second state of charge value indicative of a second energy level of said second battery group;
• and,
• means for controlling said first energy level responsive to said first and second state of charge values so as to balance the first and second energy levels.

A circuit for balancing energy levels between a first battery group and a second battery group in a battery pack, said first and second battery groups connected across a first current bus and said first battery group further connected across a second current bus, said circuit comprising:

• means for generating a first state of charge value indicative of a first energy level of said first battery group;
• means for generating a second state of charge value indicative of a second energy level of said second battery group;
• and,
• means for controlling said first energy level responsive to said first and second state of charge values,
• wherein said controlling means includes means for charging said first battery group to thereby balance said first energy level of said first battery group with said second energy level of said second battery group wherein said charging means includes:
• means for generating a reference current value responsive to said first and second state of charge values;
• means for comparing said reference current value to a first current level of a first current provided by said first battery group to said second current bus to thereby obtain a current error value;
• and,
• means for providing a second current to said first battery group responsive to said current error value.