All electric range extender electrical topology for a battery electric vehicle

A power converter for an electric vehicle include a connection interface for coupling an external battery to a first bus. The power converter includes a first set of switching devices configured to transfer power between a charge port and the first bus, and a second set of switching devices configured to transfer power between the first bus and a second bus coupled to a traction battery. The power converter includes a controller programmed to control a voltage level of the first bus to different nominal operating voltages based in different operating modes.

TECHNICAL FIELD

This application generally relates to a power distribution system for connecting an external battery to an electric vehicle.

BACKGROUND

Widespread adoption of electric vehicles by consumers has been limited by various factors. One factor is that the cost of electric vehicles is generally greater than the cost of competing gasoline powered vehicles. Another factor is referred to as range anxiety or the fear that the electric vehicle will run out of charge without a place to charge. Manufacturers typically address the range anxiety issue by permanently installing a larger battery which further increases the cost and weight of the vehicle.

SUMMARY

A vehicle includes a traction battery. The vehicle further includes a power converter including a connection interface for coupling an external battery to a first bus and a first set of switching devices configured to selectively transfer power between a charge port and the first bus. The power converter further includes a second set of switching devices configured to selectively transfer power between the first bus and a second bus that is coupled to the traction battery. The vehicle further includes a controller programmed to operate the first and second sets to cause a first nominal voltage on the first bus in a first operating mode to transfer power from the charge port to the traction battery and operate the second set to cause a second nominal voltage, different than the first nominal voltage, on the first bus in a second operating mode to transfer power from the connection interface to the traction battery.

The controller may be further programmed to operate the second set to cause the second nominal voltage on the first bus in a third operating mode to charge the external battery coupled to the connection interface from the traction battery. The controller may be further programmed to, responsive to operating in the third operating mode, command contactors associated with the external battery to close and operate the first set to isolate the charge port from the first bus. The controller may be further programmed to transition to the third operating mode responsive to a charger being connected to the charge port and a state of charge of the traction battery exceeding a full charge level and a state of charge of the external battery being less than a predetermined threshold. The controller may be further programmed to transition from the third operating mode to the first operating mode responsive to a state of charge of the traction battery decreasing by a predetermined amount. The controller may be further programmed to, responsive to operating in the first operating mode, command contactors associated with an external battery to open to isolate the external battery from the first bus. The controller may be further programmed to, responsive to operating in the second operating mode, command contactors associated with the external battery to close and operate the first set to isolate the charge port from the first bus. The controller may be further programmed to transition to the first operating mode responsive to a charger being connected to the charge port and a state of charge of the traction battery being less than a predetermined full charge level. The controller may be further programmed to transition to the second operating mode responsive to a charger being disconnected from the charge port and the external battery being connected to the connection interface and power being demanded on the second bus.

A power converter for an electric vehicle includes a connection interface for coupling an external battery to a first bus. The power converter includes a first set of switching devices configured to transfer power between a charge port and the first bus and a second set of switching devices configured to transfer power between the first bus and a second bus coupled to a traction battery. The power converter includes a controller programmed to, responsive to a charger being coupled to the charge port and the external battery being coupled to the connection interface and a state of charge of the traction battery exceeding a predetermined threshold, operate the first set to isolate the charge port and operate the second set to change a nominal voltage of the first bus from a first nominal voltage to a second nominal voltage.

The controller may be further programmed to, responsive to the state of charge of the traction battery falling below a second predetermined threshold, command contactors associated with the external battery to open and operate the first set to couple the charger and change the nominal voltage of the first bus from the second nominal voltage to the first nominal voltage and operate the second set to supply power to the second bus for charging the traction battery. The second nominal voltage may be a voltage associated with the external battery. The controller may be further programmed to, responsive to the charger being decoupled from the charge port, operate the first set to isolate the charge port from the first bus. The controller may be further programmed to, responsive to a power demand on the second bus, operate the second set to transfer power from the first bus to the second bus. The controller may be further programmed to, responsive to the state of charge of the traction battery exceeding the predetermined threshold and a state of charge of the external battery exceeding a predetermined full charge level, operate the first set to isolate the charger and command contactors associated with the external battery to open.

A method includes by a controller, responsive to a charger being coupled to a charge port that is coupled to a first bus via a first set of switching devices, an external battery being coupled to the first bus via a connection interface, and a state of charge of a traction battery coupled to the first bus via a second set of switching devices exceeding a predetermined threshold, operate the first set to isolate the charger and operate the second set to change a nominal voltage of the first bus from a first nominal voltage to a second nominal voltage.

The method may further include, responsive to the state of charge of the traction battery falling below a second predetermined threshold, commanding contactors associated with the external battery to open and operating the first set and the second set to couple the charger and change the nominal voltage of the first bus from the second nominal voltage to the first nominal voltage for charging the traction battery. The method may further include, responsive to the charger being decoupled from the charge port, operating the first set to isolate the charge port from the first bus. The method may further include responsive to a power demand on the second bus, operate the second set to transfer power from the first bus to the second bus. The method may further include, responsive to the state of charge of the traction battery exceeding the predetermined threshold and a state of charge of the external battery exceeding a predetermined full charge level, operate the first set to isolate the charger and command contactors associated with the external battery to open.

DETAILED DESCRIPTION

FIG. 1depicts an electrified vehicle112that may be referred to as a battery-electric vehicle (BEV). The electrified vehicle112may comprise an electric machine114mechanically coupled to a gearbox116. The electric machine114may be capable of operating as a motor and a generator. The gearbox116may be mechanically coupled to or include a differential162that is configured to adjust the speed of drive shafts120that are mechanically coupled to drive wheels122of the vehicle112. The drive shafts120may be referred to as the drive axle. The electric machines114can provide propulsion and deceleration capability. The electric machines114may also act as generators and can recover energy that would normally be lost as heat in a friction braking system. In some configurations, a second electric machine and a second gearbox may be coupled to a second axle to provide all-wheel drive capability.

A battery pack or traction battery124stores energy that can be used by the electric machine114. The traction battery124may provide a high voltage direct current (DC) output. A contactor module142may include one or more contactors configured to isolate the traction battery124from a high-voltage bus152when opened and connect the traction battery124to the high-voltage bus152when closed. The high-voltage bus152may include power and return conductors for carrying current over the high-voltage bus152. The contactor module142may be integrated with the traction battery124. A power electronics module126may be electrically coupled to the high-voltage bus152. The power electronics module126is also electrically coupled to the electric machine114and provides the ability to bi-directionally transfer energy between the traction battery124and the electric machine114. For example, the traction battery124may provide a DC voltage while the electric machine114may operate with a three-phase alternating current (AC) to function. The power electronics module126may convert the DC voltage to a three-phase AC current to operate the electric machine114. In a regenerative mode, the power electronics module126may convert the three-phase AC current from the electric machine114acting as a generator to the DC voltage compatible with the traction battery124.

In addition to providing energy for propulsion, the traction battery124may provide energy for other vehicle electrical systems. The vehicle112may include a DC/DC converter module128that converts the high voltage DC output from the high-voltage bus152to a low-voltage DC level of a low-voltage bus154that is compatible with low-voltage loads156. An output of the DC/DC converter module128may be electrically coupled to an auxiliary battery130(e.g., 12V battery) for charging the auxiliary battery130. The low-voltage loads156may be electrically coupled to the auxiliary battery130via the low-voltage bus154. One or more high-voltage electrical loads146may be coupled to the high-voltage bus152. The high-voltage electrical loads146may have an associated controller that operates and controls the high-voltage electrical loads146when demanded. Examples of high-voltage electrical loads146may be a fan, an electric heating element and/or an air-conditioning compressor.

The electrified vehicle112may be configured to recharge the traction battery124from an external power source136. The external power source136may be accessed via a connection to an electrical outlet. The external power source136may be electrically coupled to a charge station or electric vehicle supply equipment (EVSE)138. The external power source136may be an electrical power distribution network or grid as provided by an electric utility company. The EVSE138may provide circuitry and controls to regulate and manage the transfer of energy between the power source136and the vehicle112. The external power source136may provide DC or AC electric power to the EVSE138. The EVSE138may have a charge connector140for coupling to a charge port134of the vehicle112. The charge port134may be any type of port configured to transfer power from the EVSE138to the vehicle112. The charge port134may be electrically coupled to an on-board power conversion module or charger132. The charger132may condition the power supplied from the EVSE138to provide the proper voltage and current levels to the traction battery124and the high-voltage bus152. The charger132may interface with the EVSE138to coordinate the delivery of power to the vehicle112. The EVSE connector140may have pins that mate with corresponding recesses of the charge port134. Alternatively, various components described as being electrically coupled or connected may transfer power using a wireless inductive coupling. For example, the charge port134may represent a receive coil and the EVES connector140may represent a transmit coil.

The electrified vehicle112may include wheel brakes144that are provided for decelerating the vehicle112and preventing motion of the vehicle112. The wheel brakes144may be hydraulically actuated, electrically actuated, or some combination thereof. The wheel brakes144may be a part of a brake system150. The brake system150may include other components to operate the wheel brakes144. For simplicity, the figure depicts a single connection between the brake system150and one of the wheel brakes144. A connection between the brake system150and the other wheel brakes144is implied. The brake system150may include a controller to monitor and coordinate the brake system150. The brake system150may monitor the brake components and control the wheel brakes144for vehicle deceleration. The brake system150may respond to driver commands and may also operate autonomously to implement features such as stability control. The controller of the brake system150may implement a method of applying a requested brake force when requested by another controller or sub-function.

Electronic modules in the vehicle112may communicate via one or more vehicle networks. The vehicle network may include a plurality of channels for communication. One channel of the vehicle network may be a serial bus such as a Controller Area Network (CAN). One of the channels of the vehicle network may include an Ethernet network defined by Institute of Electrical and Electronics Engineers (IEEE) 802 family of standards. Additional channels of the vehicle network may include discrete connections between modules and may include power signals from the auxiliary battery130. Different signals may be transferred over different channels of the vehicle network. For example, video signals may be transferred over a high-speed channel (e.g., Ethernet) while control signals may be transferred over CAN or discrete signals. The vehicle network may include any hardware and software components that aid in transferring signals and data between modules. The vehicle network is not shown inFIG. 1but it may be implied that the vehicle network may connect to any electronic module that is present in the vehicle112. A vehicle system controller (VSC)148may be present to coordinate the operation of the various components. Note that operations and procedures that are described herein may be implemented in one or more controllers. Implementation of features that may be described as being implemented by a particular controller is not necessarily limited to implementation by that particular controller. Functions may be distributed among multiple controllers communicating via the vehicle network.

It may be useful to calculate various characteristics of a battery. Quantities such as battery power capability, battery capacity, and battery state of charge may be useful for controlling the operation of a battery as well as any electrical loads receiving power from the battery. Battery power capability is a measure of the maximum amount of power a battery can provide or the maximum amount of power that the battery can receive. Battery capacity is a measure of a total amount of energy that may be stored in a battery. The battery capacity may be expressed in units of Amp-hours. Values related to the battery capacity may be referred to as amp-hour values. The battery capacity of a battery may decrease over the life of the battery.

State of charge (SOC) gives an indication of how much charge remains in a battery. The SOC may be expressed as a percentage of the total charge relative to the battery capacity remaining in the battery. The SOC may also be used by other controllers (e.g., VSC148) to control the operation of an electric vehicle. Calculation of SOC can be accomplished by a variety of methods. One possible method of calculating SOC is to perform an integration of the battery current over time. This is well-known in the art as ampere-hour integration. Additionally, a relationship between an open-circuit voltage of the battery measured after a rest period and the state of charge may be known. The SOC may be utilized by the vehicle controllers to determine when the battery has achieved a full charge. A full charge may be detected when the SOC is greater than a predetermined threshold (e.g., 95%).

The driving range of the electrified vehicle112depends on the amount of charge stored in the traction battery124. The capacity of the traction battery124is determined during design and may incorporate battery technology and developments that are available at production time. It is generally difficult to add battery storage capacity to the electrified vehicle112after production as the battery and charging systems are designed with certain capacity limits in mind. Increasing the range of the electrified vehicle generally requires incorporating a larger traction battery124with a greater capacity. Incorporating a larger traction battery adds additional weight to the vehicle. An improved solution would be to design the vehicle so that additional increments of battery capacity could be added on an as-needed basis. For example, a BEV owner planning a long trip may want to install extra battery capacity only for the long trip. The BEV owner may be able to rent the battery capacity for the long trip and return the electrified vehicle112to the original condition after the trip.

However, merely adding extra battery capacity may be difficult if the electrified vehicle112is not configured to support this option. For example, any extra batteries that may be incorporated must connect to the power distribution system of the vehicle in some manner. Without prior design efforts, connection points could present significant safety concerns because of the high-voltages typical in electrified vehicles. The components and strategies defined herein attempt to address the issue of easily connecting and managing additional battery capacity.

An All-Electric Range Extender Solution (AERES) may allow a vehicle owner to temporarily add range by installing an independent battery or other energy storage module. The AERES may be configured to operate as a power source to provide power to the high-voltage bus152during vehicle operation. The AERES may be configured to charge the traction battery124when the vehicle is not being operated or driven. The AERES may be integrated into the existing vehicle power distribution system with minimal changes. In configurations in which the AERES includes an energy storage module, such as a battery, the energy storage module should be capable of being recharged.

The AERES may interface with an electronic control module to distribute power within the vehicle. In addition to a battery, the AERES may include a fuel cell and/or solar panels to provide energy. In some configurations, the AERES may be implemented as a trailer that includes additional battery capacity.

FIG. 2depicts an example of a power distribution system200for the electrified vehicle112. The power distribution system200may be configured to connect to the EVSE138through the connector140and charge port134interface. The EVSE138may include circuitry203to condition and transfer the external source136to the EVSE connector. For example, the circuitry203may include components to manage electromagnetic interference (EMI). The circuitry203may include components to scale and filter the voltage/current from the external source136to a desired amplitude/frequency for the vehicle. The EVSE138may include a contactor204that is configured to electrically couple the conditioned output to the EVSE connector140. The output of the EVSE138may be an alternating current (AC) voltage/current signal. The output of the EVSE138may be coupled to the charge port134via the EVSE connector140.

The electrified vehicle112may include a Battery Charge Control Module (BCCM)201. The BCCM201may include circuitry and components to manage the power distribution within the electrified vehicle112. The BCCM201may receive power from the charge port134when the EVSE connector140is coupled to the charge port134. For example, terminals or conductors of the BCCM201may be electrically coupled to power and return conductors of the charge port134. The BCCM201may be configured to receive an AC power signal from the charge port134. The BCCM201may include a capacitor206that is electrically coupled across the received power input. The received power input may be passed through a coupled transformer208.

The BCCM201may include a first stage210of switching devices (e.g., A1, A2, A3, A4). The first stage210may be configured as a power converter to convert between an AC voltage and a DC voltage. The switching devices may be Insulated Gate Bipolar Transistors (IGBT) arranged in a rectifier configuration. The switching devices may include corresponding antiparallel diodes (not shown). The AC voltage signal from the charge port134may be input to the first stage210. Gate signals of the switching devices may be electrically coupled to a controller260. The controller260may be programmed to operate the switches to convert the AC voltage to a DC output voltage. The output of the first stage210may be coupled across a second capacitor212. The second capacitor212may be coupled across an intermediate high-voltage bus215. The intermediate high-voltage bus215may be at a high-voltage DC level and allows the frequency of the AC voltage to be modified between the EVSE138and final stages of the power distribution system200.

The controller260may include a microprocessor or processing unit that is configured to execute programs and instructions. The controller260may further include volatile and non-volatile memory for storing programs and data. The controller260may include timers, counters, and analog-to-digital converters to facilitate processing of inputs and outputs. The controller260may also include appropriate interface circuitry for interfacing with the various inputs and outputs.

The BCCM201may include a second stage214of switching devices (e.g., B1, B2, B3, B4). The switching devices may be Insulated Gate Bipolar Transistors (IGBT) arranged in a bidirectional power converter configuration. The switching devices may include corresponding antiparallel diodes (not shown). The second stage may be configured as a bidirectional power converter to convert between a DC voltage across the second capacitor212(also intermediate high-voltage bus215) and an AC voltage across terminals217of the second stage214. Gate signals of the switching devices may be electrically coupled to the controller260. In some operating modes, the controller260may be programmed to operate the second stage214to convert DC voltage across the second capacitor212to an AC voltage at the terminals217of the second stage214. In some operating modes, the controller260may be programmed to operate the second stage214to convert AC voltage supplied at the terminals217of the second stage214to a DC voltage across the second capacitor212.

The terminals217of the second stage214may be electrically coupled to terminals of a transformer218through an inductance216and a third capacitance220. The transformer218may provide electrical isolation between the terminals217of the second stage214and later conversion stages.

The BCCM201may include a third stage224of switching devices (e.g., C1, C2, C3, C4). The switching devices may be Insulated Gate Bipolar Transistors (IGBT) arranged in a bidirectional power converter configuration. The switching devices may include corresponding antiparallel diodes (not shown). The third stage224may be configured as a bidirectional power converter to convert between an AC voltage at terminals221of the third stage224and a DC voltage at the high-voltage bus152. The high-voltage bus152may be electrically coupled to the contactor module142. The contactor module142may include a high-side bus contactor143and a low-side bus contactor145. The contactor module142may selectively electrically couple the traction battery124to the high-voltage bus152by control signals from the controller260.

The BCCM201may further include an AERES connection interface262. The AERES connection interface262may be a connector or port that provides access to the intermediate high-voltage bus215. The AERES connection interface262allows connection of additional energy storage devices. In addition, the AERES connection interface262allows the existing stages to be used for transferring energy between the AERES and the high-voltage bus152. In some configurations, the AERES connection interface262may include connection points for connecting to each side or conductor (215A,215B) that defines the intermediate high-voltage bus215. In some configurations, the AERES connection interface262includes a High-Voltage Interlock (HVIL) interface. For example, the HVIL interface may be used to isolate any high-voltage power sources from the connectors when a connector is unplugged. The HVIL interface may include a signal conductor that is routed through all high-voltage connectors. When any of the connectors are disconnected, the signal may change state and cause the contactors to be opened. The AERES connection interface262may further include a power interface and a signal interface.

An AERES module250may be connected to or installed in the electrified vehicle112. The AERES module250may include an energy storage device252such as a battery. The AERES may include an AERES connector264that is configured to interface with the AERES connection interface262to electrically couple the AERES module250to the intermediate high-voltage bus215. The AERES module250may further include a first contactor254and a second contactor256that are configured to selectively electrically couple the energy storage device252to terminals of the AERES connector264. The AERES connector264may also include a signal interface for transferring signals through the AERES connection interface262to the controller260. For example, the signal interface may be configured to enable the controller260to operate the first contactor254and the second contactor256. The signal interface may also include a communication link with a control module of the AERES module250. The controller260may be configured to command the contactors to the open and closed states via the signal interface.

The electrical topology described allows the AERES module250to feed power to the traction battery124while providing electrical isolation with the EVSE138. To isolate the charge port134from the AERES module250, the switching devices of the first stage210may be commanded to the open state. When the switching devices of the first stage210are opened, the charge port is isolated from the intermediate high-voltage bus215.

When the AERES module250is not present in the vehicle, a dummy plug may be coupled to the AERES connection interface262. The dummy plug may include connections to complete the High-Voltage Interlock (HVIL) circuit. If the dummy plug is removed, the HVIL circuit opens, causing the contactors (e.g.,143,145) in the power distribution system200to open immediately.

The controller260may be programmed to implement a control strategy for managing the AERES module250. The power distribution system200may be operated in several distinct modes. A first mode of operation may be an external charging mode. In the external charging mode, energy may be transferred from the external source136to the traction battery124. In this mode, the AERES module250may be isolated from the intermediate high-voltage bus215.

A second mode of operation may be an AERES charging mode. In the AERES charging mode, energy may be transferred from the traction battery124to the AERES module250. In this mode, the EVSE138may be isolated from the intermediate high-voltage bus215.

A third mode of operation may be an AERES depleting mode. In the AERES depleting mode, energy may be transferred from the AERES module250to the high-voltage bus152. In this mode, the charge port134and EVSE138may be isolated from the intermediate high-voltage bus215.

The BCCM201may facilitate the transfer of energy between the various sources and energy storage devices. The nominal voltage level of the high-voltage bus152may be dictated by the traction battery124and connected loads. The voltage level of the intermediate high-voltage bus215may be different than the voltage level of the high-voltage bus152. The AERES module250may be defined to have different voltage levels. The power distribution system200may support different voltage levels for the intermediate high-voltage bus215to accommodate a variety of AERES module250specifications. For example, the AERES module250may be designed with different battery capacities and nominal voltage levels.

The BCCM201configuration allows the voltage level of the intermediate high-voltage bus215to be adjusted when the AERES module250is connected. The voltage level of the AERES module250may be reported to the controller260via the AERES connection interface262. The BCCM201allows the voltage level to change based on the mode of operation as will be described herein.

Operation in the external charging mode when the EVSE138and the AERES module250are connected may be described as follows. The controller260may monitor the state of charge of the traction battery124. While the traction battery124is less than fully charged (e.g., <99% SOC), the power distribution system200may be operated to charge the traction battery124. During traction battery charging, the AERES contactors254,256may be commanded to the open state to isolate the AERES energy storage device252from the intermediate high-voltage bus215. The first stage210may be operated to maintain the intermediate high-voltage bus215at a predetermined voltage level for charging the traction battery124. The second stage214may be operated to convert the DC voltage of the intermediate high-voltage bus215to an AC voltage having a predetermined amplitude and frequency. The input the third stage224may be an AC voltage. The third stage224may be operated to convert the AC voltage to a DC voltage at a level for charging the traction battery124.

The operating parameters such as the predetermined voltage level of the intermediate high-voltage bus215and the amplitude and frequency of the voltage provided to the transformer218may be selected to optimize the energy transfer for charging the traction battery124from the external source136. The intermediate high-voltage bus215may be maintained at a nominal voltage level to match the predetermined voltage level. The nominal voltage level may define a rated voltage level and may represent a setpoint for the desired operating mode. As such, the actual voltage may vary about the nominal voltage level. The controller260may operate the switching devices to control the voltage level to the nominal voltage level. The nominal voltage level may be dependent on the operating mode.

In the external charging mode, a first set of switching devices (defined as the first stage210) may be operated to maintain a first nominal voltage across the intermediate high-voltage bus215. A second set of switching devices (defined as the second stage214and the third stage224) may be operated to transfer energy from the intermediate high-voltage bus215to the high-voltage bus152and maintain the high-voltage bus152at a predetermined voltage level. The predetermined voltage level may be a voltage level that is capable of charging the traction battery124. For example, the predetermined voltage level may be a voltage that is greater than the open-circuit voltage of the traction battery124.

When the traction battery124becomes fully charged (e.g., 100% SOC), the power distribution system200may be operated to support charging of the AERES module250(transition to AERES charging mode). In the AERES charging mode, the set of switching devices (first stage210) may be operated to open the switching devices. When the switching devices are operated in the open state, no current can flow between the EVSE138and the intermediate high-voltage bus215. In this state, the EVSE138and charge port134are isolated from the other stages. In the AERES charging mode, the traction battery124may provide energy to charge the AERES module250. The AERES contactors254,256may be operated in the closed state to electrically couple the intermediate high-voltage bus215to the AERES storage device252. The controller260may monitor the state of charge of the AERES energy storage device252.

The nominal voltage level of the intermediate high-voltage bus215may be selected to be compatible with the AERES energy storage device252. In some configurations, the nominal voltage level for charging the AERES energy storage device252may be different than the nominal voltage level for transferring energy between the EVSE138and the traction battery124. Prior to coupling the AERES energy storage device252via the contactors254,256the controller260may operate the switching devices of the second set of switching devices (e.g., second stage214and the third stage224) to set the voltage of the intermediate high-voltage bus215to the desired nominal voltage level. The voltage level of the intermediate high-voltage bus215may be selected as the charging voltage for the AERES energy storage device252. For example, the nominal voltage level of the intermediate high-voltage bus215may be set to a value greater than the open-circuit voltage of the AERES energy storage device252.

The third stage224may be operated to convert the DC voltage from the traction battery124/high-voltage bus152to an AC voltage that is input to a winding of the transformer218. The other winding of the transformer218may supply the second stage214(terminals217) with an AC voltage. The third stage224may be operated to provide the AC voltage with a predetermined amplitude and frequency. The second stage214may be operated to convert the AC voltage from the transformer218to a DC voltage at the intermediate high-voltage bus215. Note that the nominal voltage level in this mode of operation may be different than the nominal voltage level in the external charging mode.

In the AERES charging mode, the first set of switching devices (defined as the first stage210) may be operated to isolate the charge port134from the intermediate high-voltage bus215. The second set of switching devices (defined as the second stage214and the third stage224) may be operated to transfer energy from the high-voltage bus152/traction battery124to the intermediate high-voltage bus215and maintain the intermediate high-voltage bus215at a nominal voltage level to facilitate charging of the AERES energy storage device252.

The controller260may monitor the charging of the AERES energy storage device252. In addition, the controller260may monitor the amount of charge depleted from the traction battery124(e.g., change in the state of charge). The controller260may monitor the reduction in the state of charge of the traction battery124. The controller260may interrupt the charging of the AERES energy storage device252responsive to the state of charge of the traction battery124being reduced by a predetermined amount. For example, the controller260may allow a five percent change in traction battery state of charge. The controller260may also monitor the state of charge of the AERES energy storage device252. Charging of the AERES energy storage device252may be terminated when the state of charge of the AERES energy storage device252exceeds a predetermined full charge threshold. The predetermined full charge threshold may be a level indicative of a full charge or may be a user defined threshold.

After terminating charging of the AERES energy storage device252, the controller260may operate the power distribution system200to charge the traction battery124. The controller260may transition to the external charging mode as described above. The power distribution system200may alternate between the external charging mode and the AERES charging mode until the AERES energy storage device252and the traction battery124are charged to the corresponding full charge values. When the traction battery124and the AERES energy storage device252are fully charged, all contactors may be opened.

When the EVSE connector140is disconnected from the charge port134, the system may operate in the AERES depleting mode. The controller260may transition to the AERES depleting mode responsive to a power demand on the high-voltage bus152. In the AERES depleting mode, energy from the AERES energy storage device252may be supplied to the high-voltage bus152. In some configurations, the AERES energy storage device252may supplement the energy provided by the traction battery124. That is, both the traction battery124and the AERES energy storage device252may provide power to the high-voltage bus152. In other configurations, the AERES energy storage device252may be used responsive to the state of charge of the traction battery124falling below a threshold.

In the AERES depleting mode of operation, the controller260may operate the switching devices of the first stage210to isolate the charge port134from the intermediate high-voltage bus215. For example, the switching devices may be commanded to be in the open or non-conductive state. The controller260may command the AERES contactors254,256to the closed state to electrically couple the intermediate high-voltage bus215to the AERES energy storage device252. The AERES energy storage device252may provide a nominal voltage on the intermediate high-voltage bus215that is the nominal voltage rating of the AERES energy storage device252. The nominal voltage may be different than the nominal voltage of the high-voltage bus152. The controller260may operate the switching devices of the second stage214to convert the DC voltage of the intermediate high-voltage bus215to an AC voltage at the terminals217of the second stage214. The AC voltage feeds the transformer218that provides an AC voltage at terminals221of the third stage224. The AC voltage amplitude at the terminals221of the third stage224may be different than the AC voltage amplitude at the terminals217of the second stage214. For example, the amplitude may be affected by a turns ratio of the transformer218. The controller260may control the frequency of the AC voltage by controlling the switching devices.

The controller260may transition to the AERES depleting mode responsive to the EVSE138being decoupled from the charge port134, the AERES module250being connected to the AERES connection interface262, and the presence of a demand for power on the high-voltage bus152. The demand for power on the high-voltage bus152may be associated with an ignition on condition of the vehicle (e.g., key in run position). In the AERES depleting mode, the first set of switching devices (defined as the first stage210) may be operated to isolate the charge port134from the intermediate high-voltage bus215. The second set of switching devices (defined as the second stage214and the third stage224) may be operated to transfer energy from the intermediate high-voltage bus215to the high-voltage bus152to maintain the high-voltage bus152at a nominal voltage level of the traction battery124.

The controller260may be programmed to monitor the states of charge of the traction battery124and the AERES energy storage device252, when connected. The controller260may also monitor the connection status of the EVSE138. The controller260may transition between the operating modes based on the described conditions to extend the range of the vehicle112and to manage charging of both the traction battery124and the AERES energy storage device252.

FIG. 3depicts an alternative power distribution system300. Elements having the same reference numbers may operate as described previously and the description may not be repeated. The power distribution system300may include a BCCM301. The BCCM201may include circuitry and components to manage the power distribution within the electrified vehicle112. The BCCM301may receive power from the charge port134when the EVSE connector140is coupled to the charge port134. For example, terminals or conductors of the BCCM301may be electrically coupled to power and return conductors of the charge port134. The BCCM301may be configured to receive an AC power signal from the charge port134. The BCCM301may include a capacitor206that is electrically coupled across the received power input. The received power input may be passed through a coupled transformer208. The main difference in the BCCM301configuration is the removal of the AERES connection interface262that connects to the intermediate high-voltage bus215. In this configuration, the BCCM301may not directly interface with the AERES module250.

The BCCM301may include the first stage210, the second stage214, and the third stage224that are configured to transfer power between the EVSE138and the traction battery124. The power distribution system300may include a controller360that is configured to operate the switching devices and control the overall transfer of power between components.

The power distribution system300may include an AERES converter module302that is configured to transfer power between the high-voltage bus152and the AERES module250. In this configuration, the AERES converter module302is electrically coupled to the high-voltage bus152in a manner similar to other high-voltage electrical loads. In this configuration, the intermediate high-voltage bus215is not coupled to the AERES module250.

The power distribution system300may further include an AERES connection interface362that is configured to connect the AERES module250to the AERES converter module302. The AERES module250may include a cable or connector364that is configured to connect to the AERES connection interface362. The AERES connector364may include power and signal conductors to enable transfer of power and control signals between the controller360and the AERES module250. The AERES connector364may include HVIL signals that cooperate with the HVIL system to ensure safety. When the AERES connector364is not connected to the AERES connection interface362, the power distribution system300may isolate all high-voltage sources from the high-voltage buses. To operate the vehicle without the AERES module250, a dummy plug may be inserted in the AERES connection interface362. The dummy plug may provide the correct HVIL signals to permit operation of the power distribution system300.

The AERES converter module302may include a first stage306of switching devices (e.g., E1, E2, E3, E4) arranged in a bidirectional power converter to convert between a DC voltage on the high-voltage bus152and an AC voltage across a first winding of a transformer312. The AERES converter module302may include a second stage304of switching devices (e.g., D1, D2, D3, D4) arranged as a bidirectional power converter to converter between a DC voltage of the AERES module250to an AC voltage across a second winding of the transformer312. The AERES converter module302may further include an inductance308and a first capacitance coupled between the second stage304and the second winding of the transformer312. The AERES converter module302may further include a second capacitance314coupled between the first stage306and the first winding of the transformer312.

The AERES module250may be as described previously. The AERES converter module302may be operative to transfer power between the AERES energy storage device252and the high-voltage bus152. A charging strategy may be implemented by the controller360. The controller360may be programmed to first charge the traction battery124to a predetermined charge level. In the traction battery charging mode, the controller360may command the AERES contactors254,256to be open. When the traction battery124has met or exceeded a predetermined state of charge representing a full charge, the controller360may command the AERES contactors254,256to close.

The controller360may then operate the power distribution system300to charge the AERES energy storage device252. The controller360may determine the charge current that is needed to charge the AERES energy storage device252. For example, the controller360may receive AERES module250parameters via the AERES connection interface362. The controller360may then operate the BCCM301to provide the charging current to the high-voltage bus152. The controller360may then operate the AERES converter module302to provide a charging voltage to the AERES energy storage device252. The controller360may be configured to operate the switching devices to generate the proper amplitude and frequency for efficiently transferring power to the AERES energy storage device252.

When the EVSE138is not connected, the controller360may operate the AERES converter module302to transfer power from the AERES energy storage device252to the high-voltage bus152. The controller360may initiate the energy transfer responsive to a power demand on the high-voltage bus152. When the power demand is detected, the controller360may command the AERES contactor254,256to close. The controller360may then operate the AERES converter module302to transfer energy from the AERES energy storage device252to the high-voltage bus152.

In another mode of operation, the traction battery124may be charged from the external source136and the AERES energy storage device252at the same time. In this mode of operation, the controller360may operate the BCCM301to transfer energy from the external source136to the high-voltage bus152. The controller360may operate the AERES contactors254,256to couple the AERES energy storage device252to the AERES converter module302. The controller360may operate the switching devices of the AERES converter module302(first stage306and second stage304) to output a current to the high-voltage bus152for charging the traction battery124. This mode of operation permits faster charging of the traction battery124. When the traction battery124has achieved a full charge level (e.g., at or near 100% SOC), the main contactors142may be opened. The controller360may continue to operate the BCCM301to transfer energy to the high-voltage bus152for charging the AERES energy storage device252. During this time, the controller360may operate the AERES converter module302to transfer energy from the high-voltage bus152to the AERES energy storage device252. Further, in this mode of operation, the voltage level of the high-voltage bus152may be changed from the first nominal voltage level to a second nominal voltage level. The first nominal voltage level may be a level suitable for efficiently charging the traction battery124. The second nominal voltage level may be a level suitable for efficiently charging the AERES energy storage device252. When the state of charge of the AERES energy storage device252exceeds a full charge threshold, the controller360may open the AERES contactors254,256to isolate the AERES energy storage device252. The controller360may operate the BCCM301to stop transferring energy from the external source136. This traction battery dual-charging mode may allow for more rapid charging of the traction battery.

The main difference between the power distribution systems is that the power distribution system ofFIG. 2does not use a separate power converter. The system ofFIG. 2can utilize a single power converter to manage the power flow between components. The configuration ofFIG. 3may be simpler to incorporate into the power distribution system but requires the additional power converter which may add cost to the vehicle.

FIG. 4depicts a flow chart for a possible sequence of operations for controller the BCCM201when that AERES module250is coupled via the AERES connection interface262. At operation402, a check may be performed to determine if the EVSE138is connected. For example, the controller260may determine if the EVSE connector140is coupled to the charge port134via a hardware signal. The connection may also be detected if the controller260establishes communication with the EVSE138. If the EVSE138is connected, then operation414may be performed.

At operation414, a check may be performed to determine if the state of charge of the traction battery124is less than a predetermined threshold. The predetermined threshold may be a state of charge level that is indicative of a full state of charge. If the traction battery state of charge is less than the full level, then charging of the traction battery124may be performed. At operation416, the AERES module250may be isolated from the intermediate high-voltage bus215. For example, the controller260may command the AERES contactors254,256to open. At operation418, the controller260may operate the BCCM201to charge the traction battery124from the EVSE138. The controller260may operate the switching devices to transfer power between the EVSE138and the high-voltage bus152. In this mode of operation, the nominal voltage of the intermediate high-voltage bus215may be controlled to a first nominal voltage level. The first nominal voltage level may be a voltage level that allows for maximizing efficiency of the energy transfer to the traction battery124.

If the traction battery state of charge has reached the full charge level at operation414, then the AERES energy storage device252may be charged from the traction battery124. At operation420, a check may be performed to determine if the state of charge of the AERES energy storage device252is less than a full charge level. If the AERES state of charge is less than the full charge level, the AERES energy storage device252may be charged from the traction battery124. At operation424, the charge port134and the EVSE138may be isolated from the intermediate high-voltage bus215. For example, the first set of switching devices (e.g., first stage210) may be commanded to the open or non-conducting state. At operation426, the AERES energy storage device252may be connected to the intermediate high-voltage bus215. For example, the controller260may command the AERES contactors254,256to close. At operation428, the BCCM201may be operated to charge the AERES energy storage device252from the traction battery124. For example, the controller260may operate the second set of switches to transfer energy from the traction battery124to the AERES energy storage device252. In this mode of operation, the nominal voltage level of the intermediate high-voltage bus215may be controlled at a second nominal voltage level. The second nominal voltage level may be different than the first nominal voltage level used when charging the traction battery124. The second nominal voltage may be a voltage level that is above a rated voltage of the AERES energy storage device252.

At operation430, a check may be performed to determine if the traction battery state of charge has fallen a predetermined amount (e.g., K) below the full charge level. For example, the predetermined amount may be ten percent. If the traction battery state of charge has fallen below the predetermined level, operations starting at402may be repeated. The expected result may be that the system may transition to the traction battery charging mode. If the traction battery state of charge has not fallen below the predetermined level, operations starting at operation420may be repeated (e.g., continue charging AERES energy storage device252from the traction battery124).

At operation402, if the EVSE is not connected, operation404may be performed. At operation404, the charge port may be isolated from the intermediate high-voltage bus215. For example, the first stage210may be operated such that switching devices are in the open or non-conducting state. At operation406, a check may be performed to determine if a demand for power from the high-voltage bus152is present. A demand for power may correspond to an ignition run condition (e.g., key in run position, start button pressed). The demand for power may correspond to a current draw from the high-voltage bus152exceeding a predetermined threshold. If there is not demand for power from the high-voltage bus152, operation412may be performed to isolate the AERES energy storage device252from the intermediate high-voltage bus215. For example, the controller260may command the AERES contactors254,256to the open state to isolate the AERES energy storage device252.

If there is a demand for power, operation408may be performed. At operation408, the AERES energy storage device252may be connected to the intermediate high-voltage bus215. For example, the controller260may command the AERES contactors254,256to the closed or conducting state. At operation410, the BCCM201may be operated to provide power to the high-voltage bus152from the AERES energy storage device252. For example, the controller260may operate the switching devices to transfer energy from the intermediate high-voltage bus215to the high-voltage bus152as described previously herein. Operations starting from operation402may be repeated.

The power distribution system allows existing components to be utilized with minimal changes to extend the range of the electrified vehicle. The system allows battery modules with different specifications to be connected to the vehicle. The system allows the vehicle range to be increased when needed without adding additional cost to the vehicle. Range-extending capacity may be rented or leased for periods of time that it is needed. The system allows for battery capacity to be increased with battery technology that may not have been available at the time of vehicle purchase.