Method for minimizing generator load on internal combustion engine
View Patent ↗A method is disclosed for starting a generator ( 10 ) from an internal combustion engine ( 14 ) to allow the generator ( 10 ) to charge a battery ( 32 ). The generator ( 10 ) includes a field bridge ( 36 ), having first ( 72 ) and second ( 74 ) switches, and a multiphase inverter ( 30 ), having upper ( 60, 62, 64 ) and lower ( 66, 68, 70 ) halves of switches. The method includes the step of providing a voltage from the battery ( 32 ) to the internal combustion engine ( 14 ). The voltage is used to crank the internal combustion engine ( 14 ). The first ( 72 ) and second ( 74 ) switches are closed to conduct and maximize the field current in the generator ( 10 ). The method includes the step of identifying when the internal combustion engine ( 14 ) is transitioning from a cranking state to an idling state. The method then switches the first ( 72 ) and second ( 74 ) switches off to decrease the field current to zero. The method also turns the lower half of the switches ( 66, 68, 70 ) of the multiphase inverter on to quicken the decrease of the field current in the generator ( 10 ) to zero. This further reduces the amount of power consumed by the generator ( 10 ) to allow the internal combustion engine ( 14 ) to reach its idling state.
1. A method for starting of an alternator ( 10 ) from an internal combustion engine ( 14 ) to charge a battery ( 32 ), wherein alternator ( 10 ) includes a field bridge ( 36 ), having first ( 72 ) and second ( 74 ) switches, and a multiphase inverter ( 30 ), having upper ( 60 , 62 , 64 ) and lower ( 66 , 68 , 70 ) halves of switches, the method comprising the steps of:
providing a voltage from the battery ( 32 ) to the internal combustion engine ( 14 );
cranking the internal combustion engine ( 14 );
conducting the first ( 72 ) and second ( 74 ) switches to maximize the field current in the alternator ( 10 );
switching the first ( 72 ) and second ( 74 ) switches off to decrease the field current to zero; and
turning on one of the upper ( 60 , 62 , 64 ) and lower ( 66 , 68 , 70 ) halves of switches of the multiphase inverter ( 30 ) to quicken the removal of the load from the alternator ( 10 ) to the internal combustion engine ( 14 ) to further reduce the amount of power consumed by the alternator ( 10 ) to allow the internal combustion engine ( 14 ) to reach the idling state.
2. A method as set forth in claim 1 including the step of turning off the one of the upper ( 60 , 62 , 64 ) and lower ( 66 , 68 , 70 ) halves of switches after the internal combustion engine ( 14 ) enters the idling state.
3. A method as set forth in claim 2 wherein the step of turning off the one of the upper ( 60 , 62 , 64 ) and lower ( 66 , 68 , 70 ) halves of switches occurs in less than 50 milliseconds from the step of turning on the one of the upper ( 60 , 62 , 64 ) and lower ( 66 , 68 , 70 ) halves of switches.
4. A method as set forth in claim 3 including the step of identifying when the internal combustion engine ( 14 ) is transitioning from a cranking state to an idling state.
5. A method as set forth in claim 4 wherein the step of identifying occurs prior to the step of switching.