Control of auxiliary power module contactor for vehicle

Abstract

According to several aspects, a method for controlling an auxiliary power module (APM) contactor of a vehicle may include recording a plurality of actuations of the APM contactor within a time step. The plurality of actuations includes a plurality of auxiliary battery charging actuations and a plurality of accessory actuations. The method may also include comparing the amount of the plurality of accessory actuations to a predetermined accessory actuation threshold. The method may also include limiting future actuation of the APM contactor in response to determining that the amount of the plurality of accessory actuations is greater than or equal to the predetermined accessory actuation threshold.

Description

Technical Field

[0001] This disclosure relates to systems and methods for controlling the electrical system of a vehicle. Background Technology

[0002] To improve passenger comfort and vehicle performance, vehicles can be equipped with an energy storage and distribution system configured to supply power to various systems and components of the vehicle. The energy storage and distribution system may include a rechargeable energy storage system (RESS) and a power electronics system. The RESS may include a high-voltage traction battery configured to store large amounts of energy for use by the vehicle's propulsion systems (e.g., electric motors and / or hybrid electric motors) and a low-voltage auxiliary battery configured to store small amounts of energy for use by vehicle accessories (e.g., headlights, climate control systems, entertainment systems, safety / alarm systems, etc.). The power electronics system may include power conversion devices (e.g., auxiliary power modules (APM), DC / DC converters, etc.) and power switches for switching between high-voltage and low-voltage vehicle systems. However, due to the frequent power requests from vehicle accessories, current vehicle energy storage and distribution systems may not adequately mitigate wear and tear on power electronics system components.

[0003] Therefore, while current vehicle power storage and distribution systems and methods have achieved their intended purpose, a new and improved system and method is still needed to control the vehicle's auxiliary power module (APM) contactor. Summary of the Invention

[0004] According to several aspects, a method for controlling an auxiliary power module (APM) contactor of a vehicle is provided, the method including recording multiple actuations of the APM contactor within a time step. The multiple actuations include multiple auxiliary battery charging actuations and multiple accessory actuations. The method may further include comparing the amounts of the multiple accessory actuations with a predetermined accessory actuation threshold. The method may further include limiting future actuations of the APM contactor in response to determining that the amounts of the multiple accessory actuations are greater than or equal to the predetermined accessory actuation threshold.

[0005] In another aspect of this disclosure, recording each of the plurality of actuations of the APM contactor may further include detecting the actuation of the APM contactor. Recording each of the plurality of actuations of the APM contactor may further include, in response to detecting the actuation of the APM contactor, incrementing a total actuation count variable in a non-transitory memory. Recording each of the plurality of actuations of the APM contactor may further include, in response to detecting the actuation of the APM contactor, classifying the actuation of the APM contactor. The actuation of the APM contactor is classified as one of one or more accessory actuations among a plurality of auxiliary battery charging actuations. Recording each of the plurality of actuations of the APM contactor may further include, in response to classifying the actuation of the APM contactor as one of a plurality of auxiliary battery charging actuations, incrementing an auxiliary battery charging actuation count variable in a non-transitory memory. The auxiliary battery charging actuation count variable stores the amount of the plurality of auxiliary battery charging actuations. Recording each of the plurality of actuations of the APM contactor may further include, in response to classifying the actuation of the APM contactor as one of a plurality of accessory actuations, incrementing an accessory actuation count variable in a non-transitory memory. The accessory actuation count variable stores the amount of the plurality of accessory actuations.

[0006] In another aspect of this disclosure, recording each of the plurality of actuations of the APM contactor may further include storing an actuation record in a non-transitory memory in response to classifying the actuation of the APM contactor. The actuation record includes actuation time and actuation classification.

[0007] In another aspect of this disclosure, limiting future actuation of the APM contactor may further include predicting high actuation frequency periods based at least in part on multiple actuation records in a non-transitory memory. Limiting future actuation of the APM contactor may further include actuating the APM contactor to the ON state at the beginning of the high actuation frequency period. Limiting future actuation of the APM contactor may further include actuating the APM contactor to the OFF state at the end of the high actuation frequency period, such that the APM contactor remains ON throughout the high actuation frequency period.

[0008] In another aspect of this disclosure, the method may further include determining an overall actuation trend. The overall actuation trend is the trend of multiple actuation amounts over multiple time steps. The method may further include comparing the overall actuation trend with a predetermined overall actuation threshold. The predetermined overall actuation threshold includes a predetermined expected overall actuation trend. The predetermined expected overall actuation trend is determined at least in part based on the expected lifespan of the APM contactor and the maximum actuation amount of the APM contactor. The method may further include limiting future accessory actuation and future auxiliary battery charging actuation in response to determining that the overall actuation trend is greater than or equal to the predetermined expected overall actuation trend.

[0009] In another aspect of this disclosure, classifying the actuation of the APM contactor may further include, in response to determining that the APM contactor is actuated to charge the vehicle's auxiliary battery, classifying the actuation of the APM contactor as one of a plurality of auxiliary battery charging actuations. Classifying the actuation of the APM contactor may further include, in response to determining that the APM contactor is not actuated to charge the vehicle's auxiliary battery, classifying the actuation of the APM contactor as one of a plurality of accessory actuations.

[0010] In another aspect of this disclosure, comparing the amounts of actuation of multiple accessories with a predetermined accessory actuation threshold may further include determining an accessory actuation trend. An accessory actuation trend is the trend of the amounts of actuation of multiple accessories over multiple time steps. Comparing the amounts of actuation of multiple accessories with a predetermined accessory actuation threshold may further include comparing the accessory actuation trend with the predetermined accessory actuation threshold. The predetermined accessory actuation threshold includes a predetermined expected accessory actuation trend. The predetermined expected accessory actuation trend is determined at least in part based on the expected lifespan of the APM contactor and the maximum actuation amount of the APM contactor. Comparing the amounts of actuation of multiple accessories with the predetermined accessory actuation threshold may further include determining that the amounts of actuation of multiple accessories are greater than or equal to the predetermined accessory actuation threshold in response to determining that the accessory actuation trend is greater than or equal to the predetermined expected accessory actuation trend.

[0011] In another aspect of this disclosure, the method may further include calculating the amount of auxiliary battery charging actuation available within a time step, at least in part based on the amount of actuation of a plurality of accessories, the expected life of the APM contactor, and the maximum actuation amount of the APM contactor. The method may further include estimating the estimated amount of auxiliary battery charging actuation within the time step. The method may further include comparing the amount of available auxiliary battery charging actuation with the estimated amount of auxiliary battery charging actuation. The method may further include limiting future auxiliary battery charging actuation in response to determining that the amount of available auxiliary battery charging actuation is less than the estimated amount of auxiliary battery charging actuation.

[0012] In another aspect of this disclosure, estimating the amount of auxiliary battery charging actuation within a time step may further include measuring the battery temperature of the vehicle's auxiliary battery. Estimating the amount of auxiliary battery charging actuation within a time step may further include determining an estimated energy consumed from the auxiliary battery during the time step. Estimating the amount of auxiliary battery charging actuation within a time step may further include determining the effective energy capacity of the auxiliary battery based at least in part on the battery temperature. Estimating the amount of auxiliary battery charging actuation within a time step may further include determining an estimated charging cycle of the auxiliary battery. The estimated charging cycle is characterized by a charging cycle duty cycle and a charging cycle duration. Estimating the amount of auxiliary battery charging actuation within a time step may further include estimating the amount of auxiliary battery charging actuation within the time step based at least in part on the charging cycle duty cycle and the charging cycle duration.

[0013] In another aspect of this disclosure, limiting future auxiliary battery charging actuation may also include actuating the APM contactor to an on state, such that the APM contactor is always in an on state.

[0014] According to several aspects, a system for controlling an auxiliary power module (APM) contactor of a vehicle is provided. The system may include a traction battery, an APM contactor electrically communicating with the traction battery, an auxiliary battery, low-voltage vehicle accessories, and an auxiliary power module (APM) electrically communicating with the APM contactor, the auxiliary battery, and the low-voltage vehicle accessories. The APM is configured to convert a high voltage supplied by the traction battery to a low voltage for use by the auxiliary battery and the low-voltage vehicle accessories. The system may also include a controller electrically communicating with at least the APM contactor. The controller is programmed to record multiple actuations of the APM contactor within a time step. The multiple actuations include multiple auxiliary battery charging actuations for charging the auxiliary battery and multiple accessory actuations for powering the low-voltage vehicle accessories. The controller is also programmed to compare the amounts of the multiple accessory actuations with a predetermined accessory actuation threshold. The controller is further programmed to limit future actuations of the APM contactor in response to determining that the amounts of the multiple accessory actuations are greater than or equal to the predetermined accessory actuation threshold.

[0015] In another aspect of this disclosure, to record multiple actuations of the APM contactor, the controller is also programmed to detect the actuation of the APM contactor. To record multiple actuations of the APM contactor, the controller is also programmed to increment a total actuation count variable in a non-transitory memory in response to detecting the actuation of the APM contactor. To record multiple actuations of the APM contactor, the controller is also programmed to classify the actuation of the APM contactor in response to detecting the actuation of the APM contactor. The actuation of the APM contactor is classified as one of one or more accessory actuations among multiple auxiliary battery charging actuations. To record multiple actuations of the APM contactor, the controller is also programmed to increment an auxiliary battery charging actuation count variable in a non-transitory memory in response to classifying the actuation of the APM contactor as one of multiple auxiliary battery charging actuations. The auxiliary battery charging actuation count variable stores the amount of multiple auxiliary battery charging actuations. To record multiple actuations of the APM contactor, the controller is also programmed to increment an accessory actuation count variable in a non-transitory memory in response to classifying the actuation of the APM contactor as one of multiple accessory actuations. The accessory actuation count variable stores the amounts of multiple accessory actuations. To record multiple actuations of the APM contactor, the controller is also programmed to store actuation records in non-transitory memory in response to classifying the actuations of the APM contactor. The actuation records include actuation time and actuation classification.

[0016] In another aspect of this disclosure, to limit future actuation of the APM contactor, the controller is also programmed to predict high actuation frequency periods at least in part based on multiple actuation records in a non-transitory memory. To further limit future actuation of the APM contactor, the controller is further programmed to actuate the APM contactor to the ON state at the beginning of the high actuation frequency period. To further limit future actuation of the APM contactor, the controller is also programmed to actuate the APM contactor to the OFF state at the end of the high actuation frequency period, such that the APM contactor remains ON throughout the high actuation frequency period.

[0017] In another aspect of this disclosure, in order to compare the amounts of multiple accessory actuations with a predetermined accessory actuation threshold, the controller is also programmed to determine an accessory actuation trend. The accessory actuation trend is the trend of the amounts of multiple accessory actuations over multiple time steps. To compare the amounts of multiple accessory actuations with the predetermined accessory actuation threshold, the controller is also programmed to compare the accessory actuation trend with the predetermined accessory actuation threshold. The predetermined accessory actuation threshold includes a predetermined expected accessory actuation trend. The predetermined expected accessory actuation trend is determined at least in part based on the expected lifespan of the APM contactor and the maximum actuation amount of the APM contactor. To compare the amounts of multiple accessory actuations with the predetermined accessory actuation threshold, the controller is also programmed to determine that the amounts of multiple accessory actuations are greater than or equal to the predetermined accessory actuation threshold in response to determining that the accessory actuation trend is greater than or equal to the predetermined expected accessory actuation trend.

[0018] In another aspect of this disclosure, the controller is also programmed to calculate the amount of auxiliary battery charging actuation available within a time step, at least in part, based on the amounts of actuation of a plurality of accessories, the expected life of the APM contactor, and the maximum actuation amount of the APM contactor. The controller is also programmed to estimate the estimated amount of auxiliary battery charging actuation within the time step. The controller is further programmed to compare the amount of available auxiliary battery charging actuation with the estimated amount of auxiliary battery charging actuation. The controller is also programmed to limit future auxiliary battery charging actuation in response to determining that the amount of available auxiliary battery charging actuation is less than the estimated amount of auxiliary battery charging actuation.

[0019] In another aspect of this disclosure, the system also includes an auxiliary battery temperature sensor that is in electrical communication with the controller. To estimate the estimated amount of auxiliary battery charging actuation, the controller is programmed to measure the battery temperature of the vehicle's auxiliary battery. To estimate the estimated amount of auxiliary battery charging actuation, the controller is programmed to determine the estimated energy consumed from the auxiliary battery during a time step. To estimate the estimated amount of auxiliary battery charging actuation, the controller is programmed to determine the effective energy capacity of the auxiliary battery based at least in part on the battery temperature. To estimate the estimated amount of auxiliary battery charging actuation, the controller is programmed to determine an estimated charging cycle of the auxiliary battery. The estimated charging cycle is characterized by a charging cycle duty cycle and a charging cycle duration. To estimate the estimated amount of auxiliary battery charging actuation, the controller is programmed to estimate the estimated amount of auxiliary battery charging actuation within a time step based at least in part on the charging cycle duty cycle and the charging cycle duration.

[0020] In another aspect of this disclosure, in order to limit future auxiliary battery charging actuation, the controller is also programmed to actuate the APM contactor to the on state, so that the APM contactor is always in the on state.

[0021] According to several aspects, a method for controlling an auxiliary power module (APM) contactor of a vehicle is provided. The method may include recording multiple actuations of the APM contactor within a time step. The multiple actuations include multiple auxiliary battery charging actuations and multiple accessory actuations. The method may further include comparing the amount of the multiple accessory actuations with a predetermined accessory actuation threshold. The method may further include limiting future actuations of the APM contactor in response to determining that the amount of the multiple accessory actuations is greater than or equal to the predetermined accessory actuation threshold. The method may further include calculating the amount of available auxiliary battery charging actuation within the time step based at least in part on the amount of the multiple accessory actuations, the expected lifetime of the APM contactor, and the maximum actuation amount of the APM contactor. The method may further include estimating the estimated amount of auxiliary battery charging actuation within the time step. The method may further include comparing the available amount of auxiliary battery charging actuation with the estimated amount of auxiliary battery charging actuation. The method may further include limiting future auxiliary battery charging actuations in response to determining that the amount of available auxiliary battery charging actuation is less than the estimated amount of auxiliary battery charging actuation.

[0022] In another aspect of this disclosure, comparing the amounts of actuation of multiple accessories with a predetermined accessory actuation threshold may further include determining an accessory actuation trend. An accessory actuation trend is the trend of the amounts of actuation of multiple accessories over multiple time steps. Comparing the amounts of actuation of multiple accessories with a predetermined accessory actuation threshold may further include comparing the accessory actuation trend with the predetermined accessory actuation threshold. The predetermined accessory actuation threshold includes a predetermined expected accessory actuation trend. The predetermined expected accessory actuation trend is determined at least in part based on the expected lifespan of the APM contactor and the maximum actuation amount of the APM contactor. Comparing the amounts of actuation of multiple accessories with the predetermined accessory actuation threshold may further include determining that the amounts of actuation of multiple accessories are greater than or equal to the predetermined accessory actuation threshold in response to determining that the accessory actuation trend is greater than or equal to the predetermined expected accessory actuation trend.

[0023] In another aspect of this disclosure, estimating the amount of auxiliary battery charging actuation within the estimated time step may further include measuring the battery temperature of the vehicle's auxiliary battery. Estimating the amount of auxiliary battery charging actuation within the estimated time step may further include determining an estimated energy consumed from the auxiliary battery during the time step. Estimating the amount of auxiliary battery charging actuation within the estimated time step may further include determining the effective energy capacity of the auxiliary battery based at least in part on the battery temperature. Estimating the amount of auxiliary battery charging actuation within the estimated time step may further include determining an estimated charging cycle of the auxiliary battery. The estimated charging cycle is characterized by a charging cycle duty cycle and a charging cycle duration. Estimating the amount of auxiliary battery charging actuation within the estimated time step may further include estimating the amount of auxiliary battery charging actuation within the estimated time step based at least in part on the charging cycle duty cycle and the charging cycle duration.

[0024] Further areas of application will become apparent from the description provided herein. It should be understood that these descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0026] Figure 1 This is a schematic diagram of a system for controlling an auxiliary power module (APM) contactor of a vehicle, according to an exemplary embodiment.

[0027] Figure 2 This is a flowchart of a method for controlling an auxiliary power module (APM) contactor of a vehicle according to an exemplary embodiment;

[0028] Figure 3 This is a method for controlling an auxiliary power module (APM) contactor of a vehicle, according to an exemplary embodiment. Figure 2 The flowchart (continued); and

[0029] Figure 4 This is a flowchart of a method for estimating the amount of auxiliary battery charging actuation within a time step, according to an exemplary embodiment. Detailed Implementation

[0030] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses.

[0031] In various aspects of this disclosure, battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and the like may include an auxiliary power module (APM) configured to provide power to low-voltage vehicle accessories and / or to a low-voltage auxiliary battery. In various aspects of this disclosure, the APM can be energized / de-energized via an APM contactor, which is an electrical and / or electromechanical switch used to interrupt current flow. However, APM contactors may wear out due to excessive switching cycles (i.e., actuation). Therefore, it is advantageous to prevent the APM contactor from exceeding its switching cycle design limits. Therefore, this disclosure provides new and improved systems and methods for controlling APM contactors in vehicles.

[0032] refer to Figure 1 A system for controlling an auxiliary power module (APM) contactor for a vehicle is shown, and is generally indicated by reference numeral 10. System 10 is shown together with an exemplary vehicle 12. Although a passenger vehicle is shown, it should be understood that vehicle 12 can be any type of vehicle without departing from the scope of this disclosure. System 10 generally includes a controller 14, a traction battery 16, an APM contactor 18, an auxiliary power module (APM) 20, an auxiliary battery 22, and a low-voltage vehicle accessory 24.

[0033] The controller 14 is used to implement a method 100 for controlling an auxiliary power module (APM) contactor of a vehicle, as described below. The controller 14 includes at least one processor 26 and a non-transitory computer-readable storage device or medium 28. The processor 26 may be a custom or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 14, a semiconductor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, a combination thereof, or generally a device for executing instructions.

[0034] Computer-readable storage device or medium 28 may include volatile and non-volatile memory such as read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is a persistent or non-volatile memory that can be used to store various operational variables when the processor 26 is powered off. Computer-readable storage device or medium 28 may be implemented using multiple storage devices such as programmable read-only memory (PROM), electrical PROM (EPROM), electrically erasable PROM (EEPROM), flash memory, or other electrical, magnetic, optical, or combined storage devices capable of storing data, some of which represents executable instructions used by the controller 14 to control various systems of the vehicle 12.

[0035] The controller 14 may also consist of multiple controllers that are electrically communicating with each other. The controller 14 may interconnect with additional systems and / or controllers of the vehicle 12, thereby allowing the controller 14 to access data such as the speed, acceleration, braking and steering angle of the vehicle 12.

[0036] The controller 14 communicates electrically with at least the APM contactor 18 and the auxiliary battery 22. In an exemplary embodiment, electrical communication is established using, for example, a CAN network, a FLEXRAY network, a local area network (e.g., WiFi, Ethernet, etc.), a Serial Peripheral Interface (SPI) network, etc. It should be understood that various other wired and wireless technologies and communication protocols for communicating with the controller 14 are within the scope of this disclosure. It should also be understood that, within the scope of this disclosure, electrical communication also includes the transfer of power and / or energy between electrical devices (e.g., using wired and / or wireless power transmission technologies).

[0037] The traction battery 16 stores and provides electrical energy in direct current (DC) form for propulsion and high-voltage (e.g., 400 volts) power supply for the vehicle system. In an exemplary embodiment, the traction battery 16 includes multiple battery cells (e.g., lithium-ion battery cells) connected in series and / or parallel to provide increased voltage and / or current carrying capacity. In a non-limiting example, the multiple battery cells are housed in a housing configured to protect the multiple battery cells from mechanical vibration, water intrusion, and dust intrusion. The housing is also configured to provide temperature regulation (e.g., using a liquid cooling system, a resistance heating system, etc.). In an exemplary embodiment, the traction battery 16 also includes a battery management system (BMS) configured to monitor battery characteristics, such as state of charge (SOC), state of health (SOH), temperature, etc., and to transmit these battery characteristics to a controller 14. In a non-limiting example, the BMS includes a BMS controller that communicates electrically with multiple BMS sensors disposed within the housing of the traction battery 16. In an exemplary embodiment, the traction battery 16 provides a DC voltage between a positive output terminal and a negative output terminal. The positive and negative output terminals are electrically connected to the high-voltage side of the APM 20 via the APM contactor 18, as will be discussed in more detail below. In some embodiments, the controller 14 communicates electrically with the traction battery 16, for example, to monitor the SOC of the traction battery 16.

[0038] APM contactor 18 is used to connect / disconnect APM 20 to traction battery 16. In an exemplary embodiment, APM contactor 18 is an electromechanical device designed to establish or disconnect electrical connections in a circuit carrying a high voltage. In a non-limiting example, APM contactor 18 includes a set of contacts (not shown), an electromagnet (not shown), and control circuitry (not shown). The set of contacts includes movable and fixed contacts that can be brought together or separated by the electromagnet. When the control circuitry is energized, the electromagnet generates a magnetic field. The magnetic field attracts or repels the movable contacts, thereby actuating APM contactor 18.

[0039] In operation, when the controller 14 sends a signal to the control circuit, the control circuit energizes the electromagnet and the contacts close, thereby allowing current to flow between the traction battery 16 and the APM 20. Conversely, when the control circuit de-energizes the electromagnet, the contacts open, thereby interrupting the current flow between the traction battery 16 and the APM 20. It should be understood that the APM contactor 18 can be implemented using any electronically controllable switch, including relays, solid-state electronic switches (e.g., transistors), etc., without departing from the scope of this disclosure. As described above, the APM contactor 18 communicates electrically with the controller 14.

[0040] In an exemplary embodiment, the APM contactor 18 has a finite maximum momentum due to mechanical degradation of its components (e.g., the set of contacts). Maximum momentum is the maximum number of times the APM contactor 18 can be actuated (i.e., connected or disconnected) before an expected electrical or mechanical failure is anticipated. By defining the expected lifespan of the APM contactor 18 (e.g., ten years), the nominal actuation amount allowed within a given time step (e.g., one day) can be calculated based on the maximum momentum. Maximum momentum and expected lifespan are also referred to as APM contactor design constraints.

[0041] The Auxiliary Power Module (APM) 20 is used to convert the high-voltage power supplied by the traction battery 16 into low-voltage power suitable for powering the auxiliary systems of the vehicle 12. In an exemplary embodiment, the APM 20 is implemented as a DC / DC converter, such as a buck-boost converter, a buck converter, a single-ended primary inductor converter (SEPIC), etc. It should be understood that the APM 20 can be implemented using any circuit topology or architecture operable for DC-DC power conversion. In some embodiments, the operation of the APM 20 (including, for example, active state, duty cycle, conversion ratio, voltage setpoint, etc.) can be controlled by the controller 14 using electrical signals (e.g., analog and / or digital electrical signals). The APM 20 includes a high-voltage side configured to receive high-voltage power and a low-voltage side configured to output low-voltage power. The high-voltage side of the APM 20 is connected to the traction battery 16 via an APM contactor 18, such that the controller 14 can connect / disconnect the APM 20 from the traction battery 16, thereby energizing / disconnecting the APM 20. The low-voltage side of APM 20 is connected to auxiliary battery 22 and low-voltage vehicle accessory 24, as will be discussed in more detail below. In some embodiments, controller 14 communicates electrically with APM 20, for example, to monitor power delivery to APM 20 and / or control the operation of APM 20.

[0042] The auxiliary battery 22 stores and provides electrical energy in direct current (DC) form for the low-voltage (e.g., 12 volts) power supply of the vehicle system. In a non-limiting example, the auxiliary battery 22 is used to provide electrical energy to the low-voltage vehicle accessory 24 when the APM 20 is de-energized. In an exemplary embodiment, the auxiliary battery 22 includes one or more battery cells (e.g., lead-acid battery cells) connected in series and / or parallel to provide increased voltage and / or current carrying capacity. In a non-limiting example, one or more battery cells are housed in a housing configured to protect the one or more battery cells from mechanical vibration, water intrusion, and dust intrusion. The housing is also configured to provide temperature regulation (e.g., using a liquid cooling system, a resistance heating system, etc.). In an exemplary embodiment, the auxiliary battery 22 provides a DC voltage between a positive output terminal and a negative output terminal. The positive and negative output terminals are electrically connected to the low-voltage side of the APM 20. In some embodiments, the controller 14 communicates electrically with the auxiliary battery 22, for example, to monitor the power input / output of the auxiliary battery 22 and / or the state of charge (SOC) of the auxiliary battery 22.

[0043] In an exemplary embodiment, the controller 14 communicates electrically with the auxiliary battery 22 to monitor the voltage of the auxiliary battery 22 and estimate the state of charge (SOC) of the auxiliary battery 22. If the SOC of the auxiliary battery 22 drops below a predetermined threshold (e.g., 80 percent), the controller 14 can use the APM contactor 18 to energize the APM 20 to charge the auxiliary battery 22, as will be discussed in more detail below. In some embodiments, the auxiliary battery 22 also includes a charging controller configured to manage and regulate the state of charge of the auxiliary battery 22.

[0044] The total amount of energy that the auxiliary battery 22 can store is referred to as the effective energy capacity of the auxiliary battery 22. In an exemplary embodiment, the effective energy capacity of the auxiliary battery 22 varies with temperature due to temperature-dependent chemical and / or electrochemical processes or reactions within the auxiliary battery 22, for example. Therefore, in a non-limiting example, the amount of energy required to fully charge or fully discharge the auxiliary battery 22 depends on the temperature. Therefore, the auxiliary battery 22 also includes an auxiliary battery temperature sensor 30.

[0045] An auxiliary battery temperature sensor 30 is used to measure the temperature of the auxiliary battery 22. In a non-limiting example, the auxiliary battery temperature sensor 30 includes a sensing element and a signal conditioning circuit. The sensing element detects temperature changes and converts them into an electrical signal. In a non-limiting example, the sensing element includes a thermocouple and / or a thermistor. The signal conditioning circuit amplifies and processes the electrical signal generated by the sensing element to provide temperature information to the controller 14. The auxiliary battery temperature sensor 30 communicates electrically with the controller 14 as described above.

[0046] Therefore, based on the temperature of the auxiliary battery 22 obtained using the auxiliary battery temperature sensor 30, the controller 14 can determine the effective energy capacity of the auxiliary battery 22, and thus determine the amount of energy required to charge the auxiliary battery 22 based on the SOC of the auxiliary battery 22.

[0047] The low-voltage vehicle accessory 24 is used to provide additional features and / or functions to the vehicle 12. Within the scope of this disclosure, the low-voltage vehicle accessory 24 includes any systems and / or components of the vehicle 12 configured to operate using low-voltage (e.g., 12 volts) electricity. When the APM 20 is energized to the low-voltage vehicle accessory 24 (i.e., the APM contactor 18 is closed), the low-voltage vehicle accessory 24 is powered directly from the APM 20, thereby consuming a small amount of energy from the auxiliary battery 22. When the APM 20 is de-energized (i.e., the APM contactor 18 is open), the low-voltage vehicle accessory 24 is powered by energy stored in the auxiliary battery 22.

[0048] In a non-limiting example, the low-voltage vehicle accessory 24 includes one or more of the following: a vehicle communication system (i.e., a system that allows vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2X), wireless local area network (WLAN), and / or cellular data communication), a vehicle camera system (i.e., one or more cameras disposed within / on the vehicle 12, for example, for security monitoring purposes), an alarm system, a battery heating / cooling system for the traction battery 16 and / or auxiliary battery 22, a vehicle infotainment system, interior / exterior lights, a heating, ventilation, and air conditioning (HVAC) system, etc. It should be understood that the low-voltage vehicle accessory 24 may include alternative and / or additional components without departing from the scope of this disclosure. In some embodiments, the controller 14 communicates electrically with the low-voltage vehicle accessory 24, for example, to monitor the power consumption of the low-voltage vehicle accessory 24 and / or control the operation of the low-voltage vehicle accessory 24.

[0049] refer to Figure 2 A flowchart of a method 100 for controlling an auxiliary power module (APM) contactor of a vehicle is provided. Method 100 begins at block 102 and proceeds to block 104. At block 104, controller 14 receives a request to actuate APM contactor 18. Within the scope of this disclosure, actuation of APM contactor 18 includes any switching of APM contactor 18, including from an off state to an on state or from an on state to an off state. In an exemplary embodiment, a request is received from one or more of auxiliary battery 22 and / or low-voltage vehicle accessory 24. In a non-limiting example, a request is received because auxiliary battery 22 is determined to require charging. In another non-limiting example, a request is received because low-voltage vehicle accessory 24 has been activated by an occupant of vehicle 12 or controller 14. If no request to actuate APM contactor 18 is received, method 100 proceeds to a standby state at block 106. Figure 3 (via the off-page connector 3A). If a request to actuate the APM contactor 18 is received, method 100 proceeds to block 108.

[0050] At block 108, controller 14 actuates APM contactor 18 according to the request received at block 104. In a non-limiting example, controller 14 actuates APM contactor 18 from an off state to an on state. In another non-limiting example, controller 14 actuates APM contactor 18 from an on state to an off state. After block 108, method 100 proceeds to block 110.

[0051] At block 110, controller 14 increments the total actuation count variable in the non-transitory medium 28 of controller 14. Within the scope of this disclosure, the total actuation count variable is used to store the total number (i.e., the number of) actuations of the APM contactor 18 performed within a given time step. Within the scope of this disclosure, the time step is a predetermined length of time (e.g., a day). In an exemplary embodiment, the total actuation count variable is reset to zero after the end of each time step. Following block 110, method 100 proceeds to block 112.

[0052] At block 112, controller 14 classifies the actuation of APM contactor 18 performed at block 108. In an exemplary embodiment, the actuation of APM contactor 18 performed at block 108 is classified as one of one or more accessory actuations among a plurality of auxiliary battery charging actuations. Within the scope of this disclosure, the auxiliary battery charging actuation is an actuation performed for the purpose of controlling the charging of auxiliary battery 22 (i.e., starting or ending the charging process). The accessory actuation is an actuation performed for the purpose of providing power to low-voltage vehicle accessory 24.

[0053] In an exemplary embodiment, actuation of the APM contactor 18 performed at block 108 is classified based on information stored in medium 28 of controller 14, indicating the source of the request received at block 104 (e.g., one or more flag bits). In a non-limiting example, if the APM contactor 18 is actuated to charge the auxiliary battery 22, the actuation is classified as an auxiliary battery charging actuation. Otherwise, the actuation is classified as an accessory actuation. In another exemplary embodiment, actuation of the APM contactor 18 performed at block 108 is classified based on measurements of current flowing to / from the auxiliary battery 22 and the low-voltage vehicle accessory 24 to determine the primary energy consumer. If the actuation of the APM contactor 18 performed at block 108 is classified as one of a plurality of auxiliary battery charging actuations, method 100 proceeds to block 114. If the actuation of the APM contactor 18 performed at block 108 is classified as one of a plurality of accessory actuations, method 100 proceeds to block 116.

[0054] At block 114, controller 14 increments the auxiliary battery charging actuation count variable in the non-transitory medium 28 of controller 14. Within the scope of this disclosure, the auxiliary battery charging actuation count variable is used to store the total number (i.e., the number of times) of multiple auxiliary battery charging actuations performed within a given time step. Within the scope of this disclosure, the time step is a predetermined length of time (e.g., one day). In an exemplary embodiment, the auxiliary battery charging actuation count variable is reset to zero after the end of each time step. Following block 114, method 100 proceeds to block 118, as will be discussed in more detail below.

[0055] At block 116, controller 14 increments the accessory actuation count variable in the non-transitory medium 28 of controller 14. Within the scope of this disclosure, the accessory actuation count variable is used to store the total number (i.e., the number of) accessory actuations performed within a given time step. Within the scope of this disclosure, the time step is a predetermined length of time (e.g., a day). In an exemplary embodiment, the accessory actuation count variable is reset to zero after the end of each time step. Following block 116, method 100 proceeds to block 118.

[0056] At block 118, controller 14 stores an actuation record of the actuation of APM contactor 18 performed at block 108 in medium 28 of controller 14. In other words, controller 14 stores an actuation record of APM contactor 18 performed at block 108 in medium 28 of controller 14. Within the scope of this disclosure, the actuation record includes at least the actuation time (i.e., actuation duration) of APM contactor 18 performed at block 108 and the actuation classification of the actuation of APM contactor 18 performed at block 108. The actuation classification is one of the following: auxiliary battery charging actuation or accessory actuation, as determined at block 112. In an exemplary embodiment, the actuation record also includes the current values ​​of the total actuation count variable, the auxiliary battery charging actuation count variable, and the accessory actuation count variable. In another exemplary embodiment, the actuation record also includes the remaining length and / or time in the current time step. After block 118, method 100 proceeds to block 120.

[0057] At block 120, controller 14 determines an accessory actuation trend. Within the scope of this disclosure, an accessory actuation trend is the trend (i.e., change over time) of the amount of multiple accessory actuations across multiple time steps. In an exemplary embodiment, the accessory actuation trend is represented as the total number of runs of the amount of multiple accessory actuations executed during each time step. In a non-limiting example, if the time step is one day, the accessory actuation trend would include multiple data points, including a first data point representing the sum of the amounts of multiple accessory actuations executed on the first day and all previous executions, a second data point representing the sum of the first data point and the amounts of multiple accessory actuations executed on the second day, and so on for thirty days. In another exemplary embodiment, the accessory actuation trend is represented as the amount of multiple accessory actuations executed during each time step. In a non-limiting example, if the time step is one day, the accessory actuation trend would include multiple data points representing the amount of multiple accessory actuations executed each day within the first thirty days.

[0058] In an exemplary embodiment, mathematical / statistical analysis of multiple actuation records (as discussed in reference block 118 above) stored in medium 28 of controller 14 is used to determine the actuation trend. It should be understood that the data analysis of the actuation records may include operations such as outlier detection and filtering, normalization, and / or additional data filtering or cleaning techniques. Following block 120, method 100 proceeds to block 122.

[0059] At block 122, controller 14 compares the accessory actuation trend determined at block 120 with a predetermined accessory actuation threshold. Within the scope of this disclosure, the predetermined accessory actuation threshold includes a predetermined expected accessory actuation trend. Assuming APM contactor 18 is used within the boundaries of APM contactor design constraints, the predetermined expected accessory actuation trend is the expected trend of the amount of multiple accessory actuations over multiple time steps.

[0060] In a non-limiting example, if APM contactor design constraints result in an expected total daily actuation of twenty actuations, with five actuations allocated for auxiliary charging of battery 22, the predetermined expected accessory actuation trend would include fifteen accessory actuations per day, for example, starting from the production date of vehicle 12. In a non-limiting example, if the time step is one day, the predetermined expected accessory actuation trend would include multiple data points, including a first data point representing the sum of the expected amounts of accessory actuations for the first day and all previous actuations, a second data point representing the sum of the first data point and the expected amounts of accessory actuations for the second day (i.e., fifteen accessory actuations), and so on for thirty days. In an exemplary embodiment, the predetermined expected accessory actuation trend is predetermined based on APM contactor design constraints and stored in medium 28 of controller 14.

[0061] In an exemplary embodiment, if the attachment actuation trend line defined by a plurality of data points of the attachment actuation trend determined at block 120 is higher (i.e., greater) than the expected attachment actuation trend line defined by a plurality of data points of the expected attachment actuation trend for at least a predetermined amount of time steps (where the predetermined amount is greater than or equal to zero time steps), method 100 proceeds to block 124 (via Figure 3 (The off-page connector 3B). If the attachment actuation trend line is not higher than the expected attachment actuation trend line within at least a predetermined time step, method 100 proceeds to box 126 (via... Figure 3 (The off-page connector 3C). In some embodiments, a buffer amount may also be included such that, for at least a predetermined amount of time steps, the attachment actuation trend line must be at least higher than the buffer amount of the expected attachment actuation trend line, so that method 100 proceeds to block 124.

[0062] In an exemplary embodiment, the operation of block 122 as described above is performed only after a predetermined amount of time steps (e.g., thirty time steps) have elapsed, to allow for a larger dataset of more data points in the actuated trend. In a non-limiting example, if the predetermined amount of time steps has not yet been reached, method 100 restarts at block 102 and does not perform the operation of block 122 until the predetermined amount of time steps have elapsed.

[0063] refer to Figure 3 A method 100 for controlling an auxiliary power module (APM) contactor of a vehicle is shown. Figure 2 The flowchart is continued. At block 124, controller 14 predicts high-frequency actuation periods based at least in part on multiple actuation records stored in medium 28 of controller 14 (as discussed above with reference to block 118). In an exemplary embodiment, controller 14 analyzes multiple actuation records to identify patterns of high actuation frequency within a specific time window. In a non-limiting example, controller 14 identifies patterns of high actuation frequency between 6:00 PM and 8:00 PM, Monday through Friday. Therefore, high-frequency actuation periods are determined to begin at 6:00 PM and end at 8:00 PM, Monday through Friday. It should be understood that controller 14 may use any combination of mathematical, statistical, and / or machine learning-based methods to analyze multiple actuation records and identify high-frequency actuation periods. Following block 124, method 100 proceeds to block 128.

[0064] At box 128, if the current time is not within the high actuation frequency period determined at box 124, method 100 proceeds to box 130. If the current time is within the high actuation frequency period determined at box 124, method 100 proceeds to box 132, as will be discussed in more detail below.

[0065] At block 130, controller 14 uses a default disconnect state control method to control APM contactor 18. In an exemplary embodiment, the default disconnect state control method includes actuating APM contactor 18 to a disconnect state unless a specific request to actuate APM contactor 18 to a conduction state is received at block 104. In other words, APM contactor 18 is allowed to be actuated unrestricted according to the request received at block 104. After block 130, method 100 proceeds to a standby state at block 106.

[0066] At block 132, controller 14, in response to determining that the current time falls within a high actuation frequency period determined at block 124, actuates APM contactor 18 to the ON state. In an exemplary embodiment, APM contactor 18 is actuated to the ON state at the beginning of the high actuation frequency period and actuated to the OFF state at the end of the high actuation frequency period. Therefore, APM contactor 18 remains in the ON state throughout the high actuation frequency period, thereby effectively limiting future accessory actuation and reducing the actuation amount of APM contactor 18. After block 132, method 100 proceeds to the standby state at block 106.

[0067] At block 126, controller 14 determines the total actuation trend. Within the scope of this disclosure, the total actuation trend is the trend (i.e., change over time) of multiple actuation quantities across multiple time steps. In an exemplary embodiment, the total actuation trend is represented as the total number of runs of multiple actuation quantities executed during each time step. In a non-limiting example, if the time step is one day, the total actuation trend would include multiple data points, including a first data point representing the sum of the quantities of multiple actuations executed on the first day and all previous days, a second data point representing the sum of the first data point and the quantities of multiple actuations executed on the second day, and so on for thirty days. In another exemplary embodiment, the total actuation trend is represented as the quantity of multiple actuations executed during each time step. In a non-limiting example, if the time step is one day, the total actuation trend would include multiple data points representing the quantity of multiple actuations executed each day for the previous thirty days.

[0068] In an exemplary embodiment, mathematical / statistical analysis of multiple actuation records (as discussed in reference block 118 above) stored in medium 28 of controller 14 is used to determine the overall actuation trend. It should be understood that the data analysis of the actuation records may include operations such as outlier detection and filtering, normalization, and / or additional data filtering or cleaning techniques. Following block 126, method 100 proceeds to block 134.

[0069] At block 134, controller 14 compares the total actuation trend determined at block 126 with a predetermined total actuation threshold. Within the scope of this disclosure, the predetermined total actuation threshold includes a predetermined expected total actuation trend. Assuming APM contactor 18 is used within the boundaries of APM contactor design constraints, the predetermined expected total actuation trend is the expected trend of multiple actuation quantities over multiple time steps.

[0070] In a non-limiting example, if the APM contactor design constraints result in an expected total daily actuation of twenty actuations, the predetermined expected total actuation trend would include twenty actuations per day, for example, starting from the production date of vehicle 12. In a non-limiting example, if the time step is one day, the predetermined expected total actuation trend would include multiple data points, including a first data point representing the sum of the expected actuations for the first day and all previous actuations, a second data point representing the sum of the first data point and the expected actuations for the second day (i.e., fifteen actuations), and so on for thirty days. In an exemplary embodiment, the predetermined expected total actuation trend is predetermined based on the APM contactor design constraints and stored in medium 28 of controller 14.

[0071] In an exemplary embodiment, if the total actuation trend line defined by a plurality of data points of the total actuation trend determined at block 126 is higher than (i.e., greater than) the expected total actuation trend line defined by a plurality of data points of the expected total actuation trend (where the predetermined amount is greater than or equal to zero time steps) for at least a predetermined amount of time steps, method 100 proceeds to block 136. If the total actuation trend line is not higher than the expected total actuation trend line for at least a predetermined amount of time steps, method 100 proceeds to a standby state at block 106. In some embodiments, a buffer amount may also be included such that for at least a predetermined amount of time steps, the total actuation trend line must be at least higher than the expected total actuation trend line for method 100 to proceed to block 136.

[0072] At block 136, controller 14 estimates the amount of auxiliary battery charging actuation within the estimated time step, as will be discussed in more detail below. After block 136, method 100 proceeds to block 138.

[0073] At block 138, controller 14 compares the estimated amount of auxiliary battery charge actuation determined at block 136 with the available amount of auxiliary battery charge actuation. Within the scope of this disclosure, the available amount of auxiliary battery charge actuation is determined at least in part based on the amount of multiple accessory actuations, the expected lifespan of the APM contactor, and the maximum actuation amount of the APM contactor. In a non-limiting example, if APM contactor design limitations result in an expected total daily actuation of twenty actuations and the amount of multiple accessory actuations performed that day is fifteen actuations, then the available amount of auxiliary battery charge actuation is five actuations. If the estimated amount of auxiliary battery charge actuation is less than the available amount of auxiliary battery charge actuation, method 100 proceeds to block 140. If the estimated amount of auxiliary battery charge actuation is greater than the available amount of auxiliary battery charge actuation, method 100 proceeds to block 142, as will be discussed in more detail below.

[0074] At block 140, controller 14 uses a default disconnect state control method to control APM contactor 18. In an exemplary embodiment, the default disconnect state control method includes actuating APM contactor 18 to a disconnect state unless a specific request to actuate APM contactor 18 to a conduction state is received at block 104. In other words, APM contactor 18 is allowed to be actuated unrestricted according to the request received at block 104. After block 140, method 100 proceeds to a standby state at block 106.

[0075] At block 142, controller 14 actuates APM contactor 18 to the ON state, thereby effectively limiting future auxiliary battery charging actuation. Therefore, APM contactor 18 is always in the ON state, thus reducing the actuation amount of APM contactor 18. After block 142, method 100 proceeds to the standby state at block 106.

[0076] In an exemplary embodiment, controller 14 repeatedly exits standby state 106 and restarts method 100 at block 102. In a non-limiting example, controller 14 exits standby state 106 and restarts method 100 on a timer, for example, every three hundred milliseconds.

[0077] refer to Figure 4 The diagram illustrates a flowchart of an exemplary embodiment 136a of block 136 (i.e., a method for estimating the amount of auxiliary battery charging actuation within a time step). Exemplary embodiment 136a begins at block 402. At block 402, controller 14 uses auxiliary battery temperature sensor 30 to measure the battery temperature of auxiliary battery 22. Following block 402, exemplary embodiment 136a proceeds to blocks 404 and 406.

[0078] At block 404, controller 14 determines the effective energy capacity of auxiliary battery 22 based at least in part on the battery temperature measured at block 402. In an exemplary embodiment, effective energy capacity is related to the state of health (SOH) of auxiliary battery 22 and therefore to the lifetime of auxiliary battery 22. Effective energy capacity is also related to battery temperature. In a non-limiting example, effective capacity is inversely proportional to battery temperature. In an exemplary embodiment, to determine effective energy capacity, controller 14 uses a predetermined lookup table stored in medium 28 of controller 14, which stores the relationship between battery temperature, battery lifetime, and effective energy capacity. Following block 404, exemplary embodiment 136a proceeds to block 408, as will be discussed in more detail below.

[0079] At block 406, controller 14 determines an estimated energy consumed from auxiliary battery 22 during a time step. Within the scope of this disclosure, the estimated energy consumed is an estimate of the energy released from auxiliary battery 22 over a time step (e.g., one day). In a non-limiting example, energy may be released from auxiliary battery 22 to power low-voltage vehicle accessory 24 and / or auxiliary vehicle systems. In another non-limiting example, energy may be released from auxiliary battery 22 to provide heating for traction battery 16 and / or auxiliary battery 22. Thus, in a non-limiting example, the estimated energy consumption may be correlated with the battery temperature measured at block 402. In an exemplary embodiment, to determine the estimated energy consumed, controller 14 measures the current flowing to / from auxiliary battery 22 and infers the measurement over the length of the time step. Following block 406, exemplary embodiment 136a proceeds to block 408.

[0080] At block 408, controller 14 determines an estimated charging cycle for auxiliary battery 22. Within the scope of this disclosure, the estimated charging cycle is a periodic curve estimating the timing of charging and discharging of auxiliary battery 22. In an exemplary embodiment, the estimated charging cycle is characterized by a charging cycle duty cycle and a charging cycle duration. The charging cycle duration is a period of the periodically estimated charging cycle curve (i.e., the reciprocal of the frequency). The charging cycle duty cycle indicates the percentage of the charging cycle duration during which auxiliary battery 22 is estimated to be charging. In an exemplary embodiment, to determine the estimated charging cycle, controller 14 estimates the frequency and duration at which auxiliary battery 22 needs to be charged based on the effective energy capacity of auxiliary battery 22 determined at block 404 and the estimated energy consumption of auxiliary battery 22 determined at block 406. Following block 408, exemplary embodiment 136a proceeds to block 410.

[0081] At block 410, controller 14 estimates the amount of auxiliary battery charging actuation estimated within a time step, at least in part, based on the charge cycle duty cycle and / or the charge cycle duration. In an exemplary embodiment, the amount of auxiliary battery charging actuation estimated within a time step is equal to the frequency of the estimated charge cycle (i.e., the reciprocal of the charge cycle duration) multiplied by the ratio of the time step to the charge cycle duration. It should be understood that additional methods for estimating the amount of auxiliary battery charging actuation estimated within a time step, at least in part, based on the charge cycle duty cycle and / or the charge cycle duration, are within the scope of this disclosure. Following block 410, exemplary embodiment 136a ends, and method 100 continues as described above.

[0082] The system 10 and method 100 of this disclosure have several advantages. Using system 10 and method 100, the actuation of the APM contactor 18 is limited based on design constraints, thereby mitigating premature wear or failure of the APM contactor 18. Furthermore, the limitation of APM contactor actuation is dynamically implemented based on detected periods of high usage. Long-term trends are analyzed to determine whether the actuation of the APM contactor 18 should be limited, thus allowing for increased use during short periods without disrupting the occupant experience. Additionally, system 10 and method 100 allow for differentiation between actuation for the purpose of operating vehicle accessories and actuation for the purpose of charging the auxiliary battery 22.

[0083] The descriptions in this disclosure are merely exemplary in nature, and changes that do not depart from the spirit and scope of this disclosure are intended to fall within its scope. Such changes should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A method for controlling an auxiliary power module (APM) contactor for a vehicle, the method comprising: Record multiple actuations of the APM contactor within a time step, wherein the multiple actuations include multiple auxiliary battery charging actuations and multiple accessory actuations; The amount of actuation of the plurality of accessories is compared with a predetermined accessory actuation threshold; as well as In response to determining that the amount of actuation of the plurality of accessories is greater than or equal to the predetermined accessory actuation threshold, future actuation of the APM contactor is restricted.

2. The method of claim 1, wherein recording each of the plurality of actuations of the APM contactor further comprises: Detecting the actuation of the APM contactor; In response to detecting actuation of the APM contactor, the total actuation count variable in the non-transitory memory is incremented; In response to detecting the actuation of the APM contactor, the actuation of the APM contactor is classified, wherein the actuation of the APM contactor is classified as one of the plurality of auxiliary battery charging actuations or one of the plurality of accessory actuations; In response to classifying the actuation of the APM contactor as one of the plurality of auxiliary battery charging actuations, the auxiliary battery charging actuation count variable in the non-transitory memory is incremented, wherein the auxiliary battery charging actuation count variable stores the amount of the plurality of auxiliary battery charging actuations; as well as In response to classifying the actuation of the APM contactor as one of the plurality of accessory actuations, the accessory actuation count variable in the non-transitory memory is incremented, wherein the accessory actuation count variable stores the amount of the plurality of accessory actuations.

3. The method of claim 2, wherein recording each of the plurality of actuations of the APM contactor further comprises: In response to classifying the actuation of the APM contactor, an actuation record is stored in the non-transitory memory, wherein the actuation record includes actuation time and actuation classification.

4. The method of claim 3, wherein limiting future actuation of the APM contactor further comprises: High actuation frequency periods are predicted, at least in part, based on multiple actuation records in the non-transitory memory; At the start of the high actuation frequency period, the APM contactor is actuated to the on state; as well as At the end of the high actuation frequency period, the APM contactor is actuated to the open state, so that the APM contactor remains in the on state throughout the high actuation frequency period.

5. The method according to claim 3, further comprising: Determine the overall actuation trend, wherein the overall actuation trend is the trend of the amount of the plurality of actuations over multiple time steps; The total actuation trend is compared with a predetermined total actuation threshold, wherein the predetermined total actuation threshold includes a predetermined expected total actuation trend, wherein the predetermined expected total actuation trend is determined at least in part based on the expected life of the APM contactor and the maximum actuation amount of the APM contactor. as well as In response to determining that the total actuation trend is greater than or equal to the predetermined expected total actuation trend, future accessory actuation and future auxiliary battery charging actuation are restricted.

6. The method of claim 3, wherein classifying the actuation of the APM contactor further comprises: In response to determining that the APM contactor is actuated to charge the auxiliary battery of the vehicle, the actuation of the APM contactor is classified as one of the plurality of auxiliary battery charging actuations; as well as In response to determining that the APM contactor is not actuated to charge the vehicle's auxiliary battery, the actuation of the APM contactor is classified as one of the plurality of accessory actuations.

7. The method of claim 1, wherein comparing the amount of actuation of the plurality of attachments with the predetermined attachment actuation threshold further comprises: Determine the attachment actuation trend, wherein the attachment actuation trend is the trend of the amount of the plurality of attachments actuated over multiple time steps; The accessory actuation trend is compared with the predetermined accessory actuation threshold, wherein the predetermined accessory actuation threshold includes a predetermined expected accessory actuation trend, wherein the predetermined expected accessory actuation trend is determined at least in part based on the expected life of the APM contactor and the maximum actuation amount of the APM contactor; as well as In response to determining that the attachment actuation trend is greater than or equal to the predetermined expected attachment actuation trend, the amount of the plurality of attachment actuations is determined to be greater than or equal to the predetermined attachment actuation threshold.

8. The method according to claim 1, further comprising: The amount of auxiliary battery charging actuation available within the time step is calculated at least in part based on the amount of actuation of the plurality of accessories, the expected life of the APM contactor, and the maximum actuation amount of the APM contactor. Estimate the amount of auxiliary battery charging actuation within the time step; The amount of available auxiliary battery charging actuation is compared with the estimated amount of auxiliary battery charging actuation. as well as In response to determining that the amount of available auxiliary battery charging actuation is less than the estimated amount of auxiliary battery charging actuation, future auxiliary battery charging actuation is limited.

9. The method of claim 8, wherein estimating the estimated amount of auxiliary battery charging actuation within the time step further comprises: Measure the battery temperature of the vehicle's auxiliary battery; Determine the estimated energy consumed from the auxiliary battery during the said time step; The effective energy capacity of the auxiliary battery is determined at least in part based on the battery temperature; Determine the estimated charging cycle of the auxiliary battery, wherein the estimated charging cycle is characterized by the charging cycle duty cycle and the charging cycle time period; as well as The estimated amount of auxiliary battery charging actuation within the time step is estimated at least in part based on the charging cycle duty cycle and the charging cycle duration.

10. The method of claim 8, wherein limiting future auxiliary battery charging actuation further comprises: The APM contactor is actuated to the ON state, so that the APM contactor is always in the ON state.

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