Aggregating capacity for depot charging
Systems and methods are provided for aggregating and assigning power capacity for charging electric vehicles and providing power to other loads. The systems include a DC bus system used to harmonize and combine power drawn from grid connections having different electrical characteristics such as different voltages or phase levels and from other devices such as energy storage systems and generators at the site. Using the systems and methods can help enable utility customer sites to providing electric vehicle charging, especially for multiple electric vehicles, where the sites would otherwise not have sufficient power to do so without significant and expensive service upgrades and modifications.
1. An electric vehicle charging system, comprising:
a first utility grid connection having a first alternating current (AC) signal having a first signal type;
a second utility grid connection having a second AC signal having a second signal type;
an electric vehicle charging device; and
an electrical bus system in electrical communication with the first and second utility grid connections and with the electric vehicle charging device;
wherein the electrical bus system is configured to aggregate the first AC signal and the second AC signal to a direct current (DC) signal and to convert the DC signal to a single output signal for the electric vehicle charging device based on the first AC signal and the second AC signal.
2. The electric vehicle charging system of claim 1 , further comprising:
a first electrical service panel electrically connected to the first utility grid connection;
a first rectifier electrically connected to the first electrical service panel and to the electrical bus system;
a second electrical service panel electrically connected to the second utility grid connection;
a second rectifier electrically connected to the second electrical service panel and to the electrical bus system; and
an inverter electrically connected between the electrical bus system and the electric vehicle charging device.
3. The electric vehicle charging system of claim 1 , further comprising an energy storage device electrically connected to the electrical bus system and configured to provide energy to, or store energy from, the electrical bus system.
4. The electric vehicle charging system of claim 1 , further comprising a controller configured to:
determine available power from the first utility grid connection and from the second utility grid connection;
determine demand at the electric vehicle charging device; and
control the electrical bus system to draw from the available power to supply the demand at the electric vehicle charging device.
5. The electric vehicle charging system of claim 4 , wherein determining available power comprises comparing an upper limit of a capacity of the first utility grid connection to present usage of the capacity.
6. The electric vehicle charging system of claim 4 , wherein drawing from the available power comprises prioritizing power drawn from the first utility grid connection over power drawn from the second utility grid connection.
7. The electric vehicle charging system of claim 6 , wherein the prioritization is based on a tariff or time-of-use price of electricity.
8. The electric vehicle charging system of claim 1 , further comprising an energy generator or energy storage system electrically connected to the electrical bus system and wherein the electrical bus system is configured to provide energy from the energy generator or energy storage system to the electric vehicle charging device.
9. The electric vehicle charging system of claim 8 , wherein the energy generator or energy storage system comprises an energy storage device electrically connected between the first utility grid connection and the electrical bus system.
10. An electric vehicle charging system, comprising:
a first utility grid connection of a utility customer and at a site of the utility customer;
a first service panel connected to the first utility grid connection;
a second utility grid connection of the utility customer at the site;
a second service panel connected to the second utility grid connection;
an electric vehicle charging device of the utility customer at the site;
a bus aggregating output of the first and second service panels and providing a unified output to the electric vehicle charging device; and
a controller configured to manage power provided to the electric vehicle charging device via the bus.
11. The electric vehicle charging system of claim 10 , wherein the first utility grid connection and the second utility grid connection provide different voltage access to a utility grid.
12. The electric vehicle charging system of claim 10 , wherein the first utility grid connection and the second utility grid connection provide different phase-level access to a utility grid.
13. The electric vehicle charging system of claim 10 , wherein the first service panel comprises a first trip rating and the second service panel comprises a second trip rating, wherein the controller is configured to prevent power drawn from the first and second service panels from exceeding the respective first and second trip ratings.
14. The electric vehicle charging system of claim 10 , further comprising an energy storage system connected to the bus, wherein the controller is configured to store excess energy from the first and second service panels using the energy storage system or to provide supplemental energy from the energy storage system to the electric vehicle charging device.