Digital power multiport battery charging system
The disclosed charging system has multiple charging ports emanating from a central digital power transmitter to charge a plurality of battery packs. The system comprises a centralized bulk power converter to produce a first DC voltage and multiple additive power converters. One additive power converter is assigned to each charger port. The output of each charging port is transmitted in digital power format to a receiver local to each battery pack. The receiver converts the digital power to conventional analog DC power for charging the battery packs. The bulk converter provides the majority of the power needed to charge all the battery packs simultaneously, while the additive power converters adjust for the individual characteristics of each battery pack.
1. A multiport charging system, comprising;
a plurality of charging ports, each configured for coupling to a respective battery pack;
a centralized bulk converter electrically coupled with the charging ports and controllable to provide a relatively constant first output voltage selected to provide a majority of a total charge power required for recharging all battery packs attached to the charging ports;
a plurality of additive power converters, wherein each additive power converter is assigned to an individual charging port and is configured and controllable to provide a second output voltage that is lower than the first output voltage provided to the same charging port and that, when added to the first output voltage, results in a predetermined charge to the charging port to which it is assigned; and
a control circuit configured to monitor at least the electrical current leaving the charging ports to control at least the second output voltage of the additive power converters to individually control a charging current to the battery packs attached to the charging ports based on an algorithm that optimizes at least one factor selected from customer satisfaction, price of electricity, maximizing charge rate, available capacity from a power source, and battery life, wherein the control circuitry is further configured to vary the second output voltage more greatly than is the relatively constant first output voltage provided to the same charging port.
2. The multiport charging system of claim 1 , wherein the additive power converters are placed local to the bulk converter.
3. The multiport charging system of claim 1 , wherein the additive power converters are placed local to the battery pack being charged.
4. The multiport charging system of claim 1 , wherein at least one of the additive power converters is an existing onboard charger of an electric vehicle.
5. The multiport charging system of claim 1 , wherein the bulk converter is embedded in a digital power transmitter configured to transmit power in digital power format to multiple remote digital power receivers local to the charging ports, and wherein the digital power receivers are configured to convert digital power back to conventional analog power for charging battery packs attached to the charging ports.
6. A method for charging a plurality of battery packs, the method comprising:
controlling a centralized bulk converter to provide a relatively constant first output voltage through a plurality of charging ports to respective battery packs coupled with the charging ports, wherein the first output voltage is selected to provide a majority of a total charge power required for recharging all battery packs attached to the charging ports;
controlling a plurality of additive power converters, each assigned to an individual charging port, to provide a second output voltage that is lower and more variable than the first output voltage provided to the same charging port and that, when added to the first output voltage, results in a predetermined charge to the charging port to which it is assigned; and
operating a control circuit to monitor at least the electrical current leaving the charging ports to control at least the second output voltage of the additive power converters to individually control a charging current to the battery packs attached to the charging ports based on an algorithm that optimizes at least one factor selected from the following factors: customer satisfaction, price of electricity, maximizing charge rate, available capacity from a power source and battery life, wherein the control circuit controls the second output voltage of the additive power converters to be lower than the first output voltage and to vary the second output voltage more greatly than the relatively constant first output voltage provided to the same charging port from the centralized bulk converter is varied.
7. The method of claim 6 , wherein the control circuit generates a signal that offers an option for a lower price per unit of energy in exchange for a longer charging period to an owner of at least one of the battery packs.
8. The method of claim 6 , wherein the control circuit executes an algorithm that is at least in part determined by information stored in control circuitry in at least one of the battery packs.
9. The method of claim 6 , further comprising adjusting the first output voltage to a reduced voltage necessary to accommodate the lowest-voltage battery pack attached to the system, and adjusting the bulk converter voltage upwards as the lowest-voltage battery pack charges.
10. The method of claim 9 , wherein the control circuit acts to adjust the first output voltage downward to accommodate a battery pack at a low charge state wherein, because batteries at a low state-of-charge have voltage characteristics that rise rapidly during a first portion of the charge process, any loss or reduction in charging rate to higher charge-state battery packs due to a reduced voltage from the bulk converter will be temporary.
11. The method of claim 6 , further comprising using the additive power converters to produce a negative voltage in relation to the bulk converter, wherein adding the output voltage of the bulk converter and output voltage of the additive power converter results in a combined voltage that is less than that of the bulk converter.
12. The method of claim 6 , wherein at least one of the additive power converters is an existing onboard charger of an electric vehicle.