Special purpose electric vehicles and load management systems and methods therefor
Special purpose power systems for electric vehicles, control methods and special purpose electric vehicles are disclosed. Special purpose power systems control and manage loads in special purpose devices used in special purpose vehicles such as first responder vehicles. Disclosed systems and methods offer systematic control load shedding according to user designated load circuit priorities to maintain special purpose system capabilities without degrading the electric vehicle traction system and provide control of multiple circuit connections for redundant, fault tolerant operations.
1. A special purpose (SP) power system for an electric vehicle (EV) having a traction battery, at least one traction motor powered by the traction battery, a low voltage auxiliary battery powering EV auxiliary devices and an EV controller configured to control power, charge and discharge of the traction battery and low voltage auxiliary battery, said special purpose (SP) power system, comprising: plural SP AC load circuits, each AC load circuit containing at least one AC powered SP device; plural SP DC load circuits, each DC load circuit containing at least one DC powered SP device; an SP system battery configured to deliver power to said SP load circuits; a power connection between the traction battery and SP battery; an SP control system configured to at least monitor SP system battery state parameters including current charge level, capacity, temperature, current and charge/discharge state and determine SP system battery state of charge (SOCsP) based on one or more said state parameters; and a data link between traction control system and SP control system configured to at least communicate traction system state of charge information to the SP control system; wherein the SP control system comprises one or more processors, non-transitory storage devices, user interfaces, and stored instructions that when executed by said one or more processors cause the SP control system to—control power delivered to the plural AC and DC load circuits from the SP system battery; manage charge and discharge of the SP system battery; and control power draw from the traction battery to SP power system based on criteria set in the SP control system;
wherein stored instructions further comprise instructions to: receive user inputs comprising SP load circuit priority, desired SP system run time; set SP load circuit priority in accordance with the user input or in the absence of user input based on preset SP device information received by the one or more processors; disconnect SP load circuits from the SP system battery in accordance with the SP load circuit priority based on one or both of (i) maintaining power to highest priority SP load circuits for the desired run time, and (ii) comparison of the SP system battery state of charge (SOCsP) to an SOCsp minimum, and initiate power draw from the traction battery to the SP system battery in response to measured SP power system parameters, and terminate power draw from the traction battery based on measured traction battery state of charge.
2. The system of claim 1 , wherein stored instructions further comprise instructions to: detect available external power inputs to the SP power system; where multiple available external power inputs are detected, transiently connect to each available external power input to detect power supply parameters for each available external power input; connect the SP system battery to the available external power input with highest available power input capacity.
3. The system of claim 1 , wherein stored instructions further comprise instructions to: disable lowest priority SP load circuits when SOCsp and said battery state parameters meet a first preset limit condition; and disable second lowest priority SP load circuits when SOCsp and said battery state parameters meet a second preset limit condition.
4. The system of claim 3 , wherein stored instructions further comprise instructions: present a user prompt to permit power draw by the SP power system from the traction battery when SOCsp and said battery state parameters meet a traction power draw preset limit condition; and if traction system power draw is not permitted, disable all SP load circuits, or if traction system power draw is permitted, power only highest priority SP load circuits until traction system SOC as reported to the SP control system by the traction control system reaches a traction system minimum SOC.
5. The system of claim 3 , wherein the stored instructions further comprise instructions to disable third lowest priority SP load circuits when SOCsp and said battery state parameters meet a third preset limit condition.
6. The system of claim 3 , wherein the stored instructions further comprise instructions to: enable all SP load circuits when SOCsp and said battery state parameters exceed the first preset limit condition; and enable the second lowest priority SP load circuits when SOCsp and said battery state parameters exceed the second preset limit condition but do not exceed the first preset limit condition.
7. The system of claim 1 , wherein the stored instructions further comprise instructions to: receive a desired run time; repeatedly determine based on the SOCsp and monitored battery state parameters whether the SP system battery has sufficient capacity to satisfy the desired run time with all currently enabled SP load circuits; when determined to have sufficient capacity, maintain all currently enabled SP load circuits in an enabled state; and when determined not to have sufficient capacity, disable lowest priority SP load circuits out of the currently enabled SP load circuits.
8. The system of claim 7 , wherein the stored instructions further comprise instructions to: when determined not to have sufficient capacity and only highest priority SP load circuits are enabled, draw power from the traction battery to power said highest priority SP load circuits; and discontinue said power draw from the traction battery when traction system SOC as reported to the SP control system by the traction control system reaches a traction system minimum SOC.
9. The system of claim 8 , wherein the stored instructions further comprise instructions to: present in the SP system user interface configured for user entry of SP load circuit priorities; and said SP load circuits are enabled and disabled in accordance with user entered priorities.
10. The system of claim 1 , wherein the stored instructions further comprise instructions to: when SP system battery state is determined to be not discharging, enable all SP load circuits until a charge priority mode is initiated or the SP system battery is in a discharging state; when a charge priority mode is initiated, prompt the user to input at least one of a time to full charge of the SP system battery or a specified charge rate; determine whether the input charge time or charge rate is satisfied based on current SOCsp and monitored battery state parameters; if input charge time or charge rate is satisfied maintain all currently enabled SP load circuits; and if input charge time or charge rate is not satisfied, disable lowest priority SP load circuits in reverse priority sequence until satisfied.
11. The system of claim 10 , wherein the stored instructions further comprise instructions to: when SP system battery charge/discharge state is determined to be discharging, initiate an SP load circuit load shedding control mode.
12. The system of claim 1 , wherein the SP system battery is connected to the traction battery through a dedicated DC-DC converter under control of the SP system controller.
13. The vehicle of claim 11 , wherein the SP power system further comprises a power to grid connection via a power converter under control of the SP system controller.
14. The system of claim 1 , wherein: the SP system battery comprises plural interconnected batteries; and the SP control system is further configured to detect the total capacity of available batteries of said plural interconnected batteries and to determine SOCsP, based on the detected available capacity.
15. The system of claim 1 , wherein: each SP AC load is connected to plural AC circuits via a control node; each SP DC load is connected to plural DC circuits via a control node; the SP system battery is connected to all said AC and DC circuits via a control node for each circuit; an external power supply connection is connected to all said AC and DC circuits via a control node for each circuit; and the traction battery is connected to all said AC and DC circuits via a control node for each circuit, whereby any connected AC or DC circuit can provide connections for respective AC or DC SP loads to power sources.
16. The system of claim 15 , wherein the traction auxiliary battery is connected to all said AC and DC circuits via a control node for each circuit.
17. The system of claim 15 , wherein each said control node comprises a circuit breaker controlled by the SP system controller configured to provide circuit protection and on/off switching in response to instructions from the SP system controller.
18. The system of claim 1 , wherein the SP AC loads comprise one or more of laptop, computer monitor, server power supply, air conditioning unit, and wide screen television.
19. The system of claim 1 , wherein the SP DC loads comprise two or more of perimeter scene lights, LED lighting, refrigeration unit, and communication radios.