Energy management for multiple charging stations
In order to ensure reliable power for charging electric vehicles is available at each charging station at a charging site having multiple charging stations, the systems and methods disclosed herein provide for charge transfers between batteries of such charging stations. A plurality of charging stations at a charging site are connected via a direct current (DC) bus in order to transfer energy between the charging stations, such as to balance the energy stored at the respective batteries of the charging stations. Each charging station includes a system controller controlling operation of the charging station and a DC bus connection to provide DC current from the battery to the DC bus and to provide DC current from the DC bus to the battery, as controlled by the system controller. A centralized management system may also communicate with and control aspects of operation of the respective system controllers of the charging stations.
1. A vehicle charging system for charging a vehicle, comprising:
a power input port configured to receive an alternating current (AC) input electric power from a power source;
a power conversion circuit configured to convert the AC input electric power into a direct current (DC) energy storage current;
an energy storage module comprising one or more batteries configured to receive the DC energy storage current and store electric power derived therefrom;
a vehicle coupling configured to receive a charging current from the energy storage module and to provide an electrical interconnect between the vehicle charging system and the vehicle in order to provide the charging current to the vehicle;
an inter-charger connection communicatively connected to the energy storage module and configured to non-concurrently (i) provide a DC output to an additional vehicle charging system and (ii) receive a DC input from the additional vehicle charging system via a direct connection with the additional vehicle charging system; and
a system controller comprising one or more processors configured to:
determine occurrence of a triggering condition for charge transfer between the energy storage module of the vehicle charging system and an additional energy storage module comprising one or more additional batteries of the additional vehicle charging system via the direct connection; and
in response to determining occurrence of the triggering condition, control the vehicle charging system to effect the charge transfer based upon the triggering condition by providing the DC output from the energy storage module to the additional vehicle charging system via the inter-charger connection.
2. The vehicle charging system of claim 1 , wherein:
the direct connection is a DC bus connecting a plurality of vehicle charging systems at a vehicle charging site, including the vehicle charging system and the additional vehicle charging system; and
the inter-charger connection is a DC bus connection.
3. The vehicle charging system of claim 1 , wherein:
the power conversion circuit is further configured to receive a DC current from the energy storage module and provide the charging current to the vehicle coupling using the DC current; and
the power conversion circuit is further configured to connect the energy storage module to the inter-charger connection.
4. The vehicle charging system of claim 1 , wherein the triggering condition comprises receiving a command from a centralized management system communicatively connected to the vehicle charging system and the additional vehicle charging system via one or more communication connections.
5. The vehicle charging system of claim 1 , wherein the system controller determines occurrence of the triggering condition based at least in part upon a charge level of the one or more batteries of the energy storage module and an additional charge level of the one or more additional batteries of the additional energy storage module of the additional charging system, wherein the additional charge level is received in an electronic message received from the additional charging system.
6. The vehicle charging system of claim 1 , wherein the system controller determines occurrence of the triggering condition based at least in part upon a charge imbalance between a charge level of the one or more batteries of the energy storage module of the vehicle charging system and an additional charge level of the one or more additional batteries of the additional energy storage module of the additional charging system exceeding a threshold charge differential.
7. The vehicle charging system of claim 6 , wherein the system controller determines the threshold charge differential dynamically based upon one or more of the following charging site conditions: current availability of the AC input electric power from the power source, predicted future availability of the AC input electric power from the power source, current charging demand for each of the vehicle charging system and the additional vehicle charging system, predicted future demand for each of the vehicle charging system and the additional vehicle charging system, or operational statuses of the vehicle charging system and the additional vehicle charging system.
8. The vehicle charging system of claim 1 , wherein the triggering condition comprises a discharge imbalance between the charging current provided by the vehicle coupling of the vehicle charging system and an additional charging current of an additional vehicle coupling of the additional vehicle charging system exceeding a threshold discharge differential over a predetermined time interval.
9. A method for managing energy transfers between a plurality of vehicle charging systems each configured to charge vehicles at a vehicle charging site, comprising:
receiving, via respective power input ports of each of the vehicle charging systems, an alternating current (AC) input electric power from a power source;
converting, via respective power conversion circuits of each of the vehicle charging systems, the AC input electric power into a respective direct current (DC) energy storage currents;
charging, using the respective DC energy storage currents, one or more batteries of an energy storage module of a vehicle charging system of the plurality of vehicle charging system and one or more additional batteries of an additional energy storage module of an additional vehicle charging system of the plurality of vehicle charging systems at the vehicle charging site;
determining, by a system controller of the vehicle charging system, occurrence of a triggering condition for charge transfer between the one or more batteries of the energy storage module of the vehicle charging system and the one or more additional batteries of the additional energy storage module of the additional vehicle charging system via a direct connection between the vehicle charging system and the additional vehicle charging system; and
in response to determining occurrence of the triggering condition, controlling, by the system controller, the vehicle charging system to effect the charge transfer based upon the triggering condition by providing a DC output from the energy storage module to the additional vehicle charging system via an inter-charger connection of the vehicle charging system, wherein the inter-charger connection is communicatively connected to the energy storage module and configured to non-concurrently (i) provide the DC output to the additional vehicle charging system and (ii) receive a DC input from the additional vehicle charging system via the direct connection with the additional vehicle charging system.
10. The method of claim 9 , wherein:
the direct connection is a DC bus connecting the plurality of vehicle charging systems at the vehicle charging site, including the vehicle charging system and the additional vehicle charging system; and
the inter-charger connection is a DC bus connection.
11. The method of claim 9 , further comprising:
converting, via the power conversion circuit of the vehicle charging system, a DC current from the energy storage module into a charging current; and
providing, via a vehicle coupling of the vehicle charging system, the charging current to a vehicle connected to the vehicle charging system via the vehicle coupling.
12. The method of claim 9 , wherein the triggering condition comprises receiving a command from a centralized management system communicatively connected to the vehicle charging system and the additional vehicle charging system via one or more communication connections, and further comprising:
sending, to the centralized management system via the one or more communication connections, operating data from each of the vehicle charging system and the additional vehicle charging system; and
receiving, at the system controller via the one or more communication connections, the command from the centralized management system to effect the charge transfer.
13. The method of claim 12 , further comprising:
receiving, at an additional system controller of the additional vehicle charging system via the one or more communication connections, an additional command from the centralized management system to effect the charge transfer.
14. The method of claim 9 , wherein determining occurrence of the triggering condition comprises:
determining, by the system controller, a charge level of the one or more batteries of the energy storage module of the vehicle charging system;
receiving, at the system controller, an electronic message from the additional vehicle charging system, wherein the electronic message includes an indication of an additional charge level of the one or more additional batteries of the additional energy storage module of the additional vehicle charging system;
determining, by the system controller, occurrence of the triggering condition based at least in part upon a charge imbalance between the charge level and the additional charge level exceeding a threshold charge differential.
15. The method of claim 14 , wherein the system controller determines the threshold charge differential dynamically based upon one or more of the following charging site conditions: current availability of the AC input electric power from the power source, predicted future availability of the AC input electric power from the power source, current charging demand for each of the vehicle charging system and the additional vehicle charging system, predicted future demand for each of the vehicle charging system and the additional vehicle charging system, or operational statuses of the vehicle charging system and the additional vehicle charging system.
16. The method of claim 9 , wherein the triggering condition comprises a discharge imbalance between a charging current provided to a vehicle by a vehicle coupling of the vehicle charging system and an additional charging current provided to an additional vehicle by an additional vehicle coupling of the additional vehicle charging system exceeding a threshold discharge differential over a predetermined time interval.
17. A site charging system for charging vehicles at a vehicle charging site, comprising:
a plurality of vehicle charging systems at the vehicle charging site connected via a direct current (DC) bus, each vehicle charging system comprising:
a power input port configured to receive an alternating current (AC) input electric power from a power source;
a power conversion circuit configured to convert the AC input electric power into a direct current (DC) energy storage current;
an energy storage module comprising one or more batteries configured to receive the DC energy storage current and store electric power derived therefrom;
a vehicle coupling configured to receive a charging current from the energy storage module and to provide an electrical interconnect between the vehicle charging system and the vehicle in order to provide the charging current to the vehicle;
an inter-charger connection communicatively connected to the energy storage module and to the DC bus to non-concurrently (i) provide a DC output to the DC bus and (ii) receive a DC input from the DC bus; and
a system controller comprising one or more processors configured to control charge transfers between the one or more batteries of the energy storage module of the vehicle charging system and one or more additional batteries of an additional energy storage module of an additional vehicle charging system of the plurality of vehicle charging systems via the DC bus; and
a centralized management system communicatively connected to the plurality of vehicle charging systems via one or more electronic communication connections, the centralized management system comprising one or more processors configured to:
determine occurrence of a triggering condition for a charge transfer between the respective energy storage modules of a first vehicle charging system and a second vehicle charging system of the plurality of vehicle charging systems via the DC bus; and
in response to determining occurrence of the triggering condition, control (i) the first vehicle charging system to provide DC power to the DC bus from the one or more batteries of the energy storage module of the first vehicle charging system and (ii) the second vehicle charging system to charge the one or more additional batteries of the additional energy storage module of the second vehicle charging system using the DC power from the DC bus.
18. The site charging system of claim 17 , wherein the centralized management system determines occurrence of the triggering condition based at least in part upon a charge imbalance between a charge level of the one or more batteries of the energy storage module of the first vehicle charging system and an additional charge level of the one or more additional batteries of the additional energy storage module of the second vehicle charging system exceeding a threshold charge differential.
19. The site charging system of claim 18 , wherein the centralized management system determines the threshold charge differential dynamically based upon one or more of the following charging site conditions: current availability of the AC input electric power from the power source, predicted future availability of the AC input electric power from the power source, current charging demand for each of the first vehicle charging system and the second vehicle charging system, predicted future demand for each of the first vehicle charging system and the second vehicle charging system, or operational statuses of the first vehicle charging system and the second vehicle charging system.
20. The site charging system of claim 17 , wherein the triggering condition comprises a discharge imbalance between the respective charging current provided by the respective vehicle coupling of the first vehicle charging system and the respective charging current of the respective vehicle coupling of the second vehicle charging system exceeding a threshold discharge differential over a predetermined time interval.