System and method for managing power drawn from a vehicle alternator

Abstract

The present application relates to a system for managing power drawn from a vehicle alternator to power auxiliary systems. The system includes a controller configured to: determine an output voltage of the vehicle alternator; compare the output voltage of the vehicle alternator to a threshold; and adjust power requirements of the auxiliary systems based on the comparison result.

Description

Technical Field

[0001] The present disclosure relates to a system and method for managing power drawn from a vehicle alternator. Background Art

[0002] Many different types of cargo, including, for example, food and pharmaceuticals, need to be maintained at or within a predetermined temperature range during transportation to ensure they arrive at their destination in a safe condition or acceptably fresh condition.

[0003] To meet this need, temperature control solutions have been developed for vehicles such as vans, trucks, and tractor-trailers that can be used to transport such goods by road. Such vehicles may be provided or retrofitted with a temperature control unit or system, also known as a transport refrigeration unit (TRU), that operates to maintain the temperature within the host vehicle's cargo space at a predetermined temperature or within a predetermined temperature range.

[0004] Conventional temperature control units of this type typically include temperature control components such as a compressor, pump, condenser, heat exchanger, and associated piping that form a refrigeration system, as well as electrical components such as a temperature sensor, controller, and display unit. A battery may also be provided to power the electrical components. Additionally or alternatively, a generator may be provided to generate electricity to power the electrical components and charge the battery.

[0005] Temperature control components such as pumps and compressors are typically driven mechanically by the vehicle's engine via a suitable mechanical coupling such as a drive belt. A generator (if provided) may also be driven mechanically in this manner. Summary of the Invention

[0006] The present disclosure relates to a system and method for managing the power demand of auxiliary systems that draw power from a vehicle alternator. The disclosed system and method can help ensure that the power demand of the auxiliary systems is met by the vehicle alternator, by an auxiliary battery of the auxiliary systems, or by a combination of the vehicle alternator and the auxiliary battery. The disclosed system and method monitors the output voltage of the vehicle alternator and adjusts the power demand of the auxiliary systems to meet the power output capacity of the vehicle alternator by reducing the power demand of the auxiliary systems in the event that the alternator cannot meet the power demand of the auxiliary systems, thereby meeting the power output capacity of the vehicle alternator. In the event that the alternator has excess power output capacity, the power demand of the auxiliary systems can be increased, and the excess power can be used, for example, to charge the auxiliary battery of the auxiliary systems. Additionally or alternatively, in the event that there is a difference between the power output capacity of the vehicle alternator and the power demand of the auxiliary systems, resulting in insufficient power supply to the auxiliary systems, the auxiliary battery can be used to compensate for the insufficient power provided by the vehicle alternator to the auxiliary systems.

[0007] According to a first aspect, the present disclosure provides a system for managing power drawn from a vehicle AC generator to power an auxiliary system, the system comprising: a controller configured to: determine an output voltage of the vehicle AC generator; compare the output voltage of the vehicle AC generator with a threshold; and adjust the power demand of the auxiliary system based on the comparison result.

[0008] The controller may be configured to adjust the current drawn by the auxiliary system to adjust the power demand of the auxiliary system.

[0009] The controller may be configured to switch off one or more loads of the auxiliary system to adjust the power demand of the auxiliary system.

[0010] The controller may be configured to adjust an operating mode of one or more loads of the auxiliary system to adjust a power demand of the auxiliary system.

[0011] The controller can be configured to:

[0012] If the output voltage of the vehicle alternator is greater than a threshold, the power demand on the auxiliary systems is increased.

[0013] The controller can be configured to:

[0014] If the output voltage of the vehicle alternator is less than a threshold, power demand on the auxiliary systems is reduced.

[0015] The controller can be configured to:

[0016] If the output voltage of the vehicle alternator is equal to the threshold, the power demand of the auxiliary systems is maintained.

[0017] The system may also include an auxiliary battery for powering auxiliary systems.

[0018] The controller can be configured to:

[0019] If the output voltage of the vehicle alternator is greater than a threshold, the power supply to the auxiliary battery is adjusted to charge the auxiliary battery.

[0020] The controller can be configured to:

[0021] If the output voltage of the vehicle alternator is below a threshold, coupling the auxiliary battery to the one or more loads of the auxiliary system such that the one or more loads of the auxiliary system are at least partially powered by the auxiliary battery.

[0022] The controller may comprise, for example, a proportional-integral controller.

[0023] The system may also include a buck-boost converter coupled to an output of the vehicle alternator and operative to provide a power supply to the auxiliary systems.

[0024] According to a second aspect, the present disclosure provides a method of managing power drawn from a vehicle alternator to power an auxiliary system, the method comprising:

[0025] Determine the output voltage of the vehicle's alternator;

[0026] comparing the output voltage of the vehicle's alternator to a threshold value; and

[0027] The power requirements of the auxiliary systems are adjusted based on the comparison results.

[0028] Adjusting the power demand of the auxiliary system may include, for example, adjusting the current drawn by the auxiliary system.

[0029] Additionally or alternatively, adjusting the power demand of the auxiliary system may include shutting off one or more loads of the auxiliary system.

[0030] Additionally or alternatively, adjusting the power demand of the auxiliary system may include adjusting an operating mode of one or more loads of the auxiliary system.

[0031] Additionally or alternatively, adjusting the power requirements of the auxiliary systems may include:

[0032] If the output voltage of the vehicle alternator is greater than a threshold, the power demand on the auxiliary systems is increased.

[0033] Additionally or alternatively, adjusting the power requirements of the auxiliary systems may include:

[0034] If the output voltage of the vehicle alternator is less than a threshold, power demand on the auxiliary systems is reduced.

[0035] Additionally or alternatively, adjusting the power requirements of the auxiliary systems may include:

[0036] If the output voltage of the vehicle alternator is equal to the threshold, the power demand of the auxiliary systems is maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments of the present invention will now be described strictly by way of example only and with reference to the accompanying drawings, in which:

[0038] Figure 1 is a schematic diagram showing relevant elements of the host vehicle and relevant elements of auxiliary systems that draw power from the alternator of the host vehicle;

[0039] Figure 2 is an example of a power curve showing the relationship between the speed of an alternator and the output current of the alternator;

[0040] Figure 3 is a flow chart illustrating steps in a method for managing power requirements of auxiliary systems to ensure that the power requirements of the auxiliary systems can be met without drawing power from the battery of the host vehicle;

[0041] Figure 4 is with Figure 2 The power curve shown in Figure 3 a graphical illustration of the operation of the method; and

[0042] Figure 5 is a schematic diagram showing relevant elements of the present vehicle and assistance system according to a variation of the present disclosure. DETAILED DESCRIPTION

[0043] Temperature control units for maintaining the temperature within a truck cargo compartment at a predetermined temperature or within a predetermined temperature range are evolving away from conventional designs of the type described above, which use the vehicle's engine to power components such as compressors, pumps, and the like, in favor of designs in which such components are powered by the vehicle. One disadvantage of such powered systems is that they can draw power from the vehicle's battery, which is also used to power the vehicle's low-voltage electrical systems, such as the audio system, lighting system, and the like. As will be appreciated, drawing power from the vehicle's battery in this manner can discharge the vehicle's battery and may negatively impact the operation of the vehicle's low-voltage electrical systems.

[0044] Figure 1This is a schematic diagram showing relevant elements of a host vehicle (e.g., a truck) and elements of an auxiliary system that draws power from the host vehicle's alternator or an auxiliary battery of the auxiliary system. The auxiliary system may be, for example, an electric temperature control system for maintaining the temperature within the host vehicle's cargo compartment at a predetermined temperature or within a predetermined temperature range.

[0045] exist Figure 1 In FIG. 1 , elements of the host vehicle are shown in box 110 , while elements of the auxiliary system are shown in box 130 .

[0046] The vehicle 110 includes an engine 112 that drives an alternator 114 via a suitable mechanical coupling or linkage 116, such as a drive belt, a drive shaft, a drive chain, or any other suitable mechanical coupling or linkage. Because the alternator 114 is part of the host vehicle 110 and is driven by the vehicle engine 112, the auxiliary system 130 does not control the speed of the alternator 114 and should therefore be able to operate effectively regardless of the speed of the vehicle engine 112 and / or the alternator 114.

[0047] The alternator 114 generates electrical energy that can be used to charge the battery 118 of the vehicle 110 and to power the vehicle's low-voltage electrical loads, such as the radio, interior lighting, etc. Figure 1 Indicated by the arrow labeled “LV Load”.

[0048] The vehicle 110 also includes a battery bus 120 to which the alternator 114, the vehicle battery 118, and the vehicle's low-voltage loads are coupled. The battery bus 120 distributes power from the alternator 114 and the vehicle battery 118 to supply power to the low-voltage loads, and distributes power from the alternator 114 to the vehicle battery 118 to charge the vehicle battery. In the example shown, the alternator 114 is a conventional, low-cost vehicle alternator, such as a Lundell alternator, that includes a voltage regulator for providing a nominal alternator output voltage. Those skilled in the art will be familiar with this type of alternator and will not be discussed further herein.

[0049] The auxiliary system 130 includes a first power converter 132, a second power converter 134, an auxiliary battery 136 and a high voltage load. Figure 1 denoted by arrows labeled “HV loads.” High voltage loads may include, for example, compressors, pumps, heaters, and other electrical components of a temperature control system.

[0050] First power converter 132 is configured to convert a first voltage output by alternator 114 into a second voltage different from the first voltage and to control current through first power converter 132 to provide a voltage and current suitable for powering high-voltage loads of auxiliary system 130 .

[0051] Second power converter 134 is coupled to first power converter 132 and is configured to convert the second voltage output by first power converter 132 into a third voltage different from the second voltage, and to control the current flowing through second power converter 134 to auxiliary battery 136 to provide a voltage and current suitable for charging auxiliary battery 136. Second power converter 134 is also configured to convert a fourth voltage output by auxiliary battery 136 into a fifth voltage, and to control the current flowing from auxiliary battery 136 through second power converter 134 to provide a voltage and current suitable for powering the high-voltage loads of auxiliary system 130 if and when needed.

[0052] The auxiliary battery 136 may be, for example, a 48 volt battery or a 400 volt battery.

[0053] The auxiliary system 130 also includes a controller 150 that is configured to determine the voltage at the electrical output of the alternator 114 (e.g., the voltage across the output terminals of the alternator 114) and manage the power requirements of the auxiliary system 130 to ensure that the power requirements of the auxiliary system 130 can be provided from the alternator 114 and / or the auxiliary battery 136 without drawing power from the vehicle battery 118, as will be described in detail below. The controller 150 may include, for example, a processor, microprocessor, or microcontroller executing appropriate instructions. The processor 150 may include or implement a proportional-integral (PI) controller.

[0054] Figure 2 is an example of a power curve 202 that shows the relationship between the speed of the alternator (in revolutions per minute (RPM)) and the output current of the alternator. Figure 2 As can be seen from the power curve 202 (and as will be familiar to those skilled in the art), the output current of the alternator increases (non-linearly) with the speed of the alternator. For example, the alternator may be rated or configured to provide an output current of 50 amps at 1500 RPM and an output current of 120 amps at 6000 RPM.

[0055] An alternator is specified to provide a nominal output voltage, Vnom, which is the output voltage that can be provided by the alternator provided that the total load current drawn from the alternator by any electrical loads coupled to the alternator's electrical output terminals is equal to or less than the rated current at a given alternator speed. Thus, for an alternator with a rated output current of 50 amps at 1500 RPM and a rated nominal output voltage, Vnom, of 13.5 volts, assuming the total load current does not exceed 50 amps, the output voltage of the alternator will be 13.5 volts. However, if the total load current exceeds 50 amps, the output voltage of the alternator will drop below 13.5 volts and continue to drop as the load current increases.

[0056] like Figure 2 As shown in FIG, in region 204 below the power curve 202 (i.e., where the total load current is equal to or less than the rated output current at the AC generator speed), the output voltage of the AC generator will be Vnom, while in region 206 above the power curve 202 (i.e., where the total load current is greater than the rated output current at the AC generator speed), the output voltage of the AC generator will be less than Vnom.

[0057] Reference again Figure 1 The controller 150 of the auxiliary system 130 is configured to monitor the output voltage of the alternator 114 and control the power demand of the auxiliary system 130, for example, by controlling the current drawn by the first power converter 132 to ensure that the required power can be provided by the alternator 114 alone, or by the alternator in combination with the auxiliary battery 136, without drawing power from the vehicle battery 118, as will now be described with reference to Figure 3 Provide explanation.

[0058] Figure 3 is a flow chart illustrating steps in a maximum power point tracking method that may be performed by the controller 150 to ensure that the required power can be provided by the alternator 114 alone, or in combination with the auxiliary battery 136 , without drawing power from the vehicle battery 118 .

[0059] This method (in Figure 31 . The controller 150 (shown generally at 300) begins at step 302. At step 304, the controller 150 determines the output voltage Valt of the alternator 114. The controller 150 may determine the output voltage Valt of the alternator 114 in any convenient manner. For example, the auxiliary system 130 may include a conventional voltage sensor circuit that continuously or periodically measures the output voltage Valt of the alternator 114 and reports the measured voltage Valt to the controller 150. Alternatively, the controller 150 may periodically (e.g., every millisecond) poll such a voltage sensor circuit to determine the output voltage Valt of the alternator 114.

[0060] At step 306, the controller 150 compares the alternator output voltage Valt to a threshold value Vth. The threshold value Vth may be equal to, for example, a value Vnom-dV, where Vnom is the rated nominal output voltage of the alternator 114 and dV is a constant value that provides a degree of margin to prevent a small increase in the power demand (e.g., load current) of the auxiliary system 130 from causing the alternator output voltage Valt to drop below its rated or nominal output voltage Vnom.

[0061] If the alternator output voltage Valt determined at step 304 is different from the threshold value Vth, the controller 150 adjusts (increases or decreases) the power demand of the auxiliary system 130, as described in detail below. For example, the controller 150 may be or may implement a PI (proportional-integral) regulator that takes as input the error between the rated or nominal output voltage Vnom of the alternator 114 and the output voltage Valt of the alternator 114 (as determined at step 304) and calculates or provides as output a current to be provided by the first power controller 132, thereby adjusting the power demand of the auxiliary system 130 based on the alternator output voltage Valt. The controller 150 may be configured to implement hysteresis or some other form of intelligent control to prevent frequent changes in the power demand of the auxiliary system 130 ("hunting"), which may result in unnecessary or undesirable on-off switching of the auxiliary system's loads (e.g., compressors, pumps, heaters, etc.).

[0062] If the alternator output voltage Valt is greater than the threshold Vth, then at step 308 , the controller 150 increases the power demand of the auxiliary system 130 .

[0063] For example, the controller 150 may increase (e.g., via the first power controller 132) the amount of current supplied to one or more loads (e.g., a compressor, a pump, a heater, etc.) of the temperature control system forming part of the auxiliary system 130, or may adjust the operating mode of one or more such loads, such as placing the load into a high power operating mode, or a higher power operating mode, such as a high temperature or higher temperature mode for a heater, or a high speed or higher speed mode for a pump. Alternatively or additionally, the controller 150 may cause current to be supplied or diverted to the auxiliary battery 136, or may increase the amount of current or voltage supplied to the auxiliary battery 136, thereby charging the auxiliary battery 136.

[0064] After step 308 , the method returns to step 304 where the controller 150 again determines the alternator output voltage Valt, which is again compared to the threshold value Vth at step 306 .

[0065] As a result of the comparison, if the controller 150 determines that the alternator output voltage Vout is equal to the threshold value Vth (step 310), the controller 150 maintains the power demand of the auxiliary system 130, and the method returns to step 304, where the controller 150 again determines the alternator output voltage Valt.

[0066] As a result of the comparison, if the controller 150 determines that the alternator output voltage Valt is less than the threshold Vth, then at step 314 , the controller 150 reduces the power demand of the auxiliary system 130 and / or uses the auxiliary battery 336 to supply the shortfall in power supplied by the alternator 114 .

[0067] For example, the controller 150 can reduce the power demand of the auxiliary system 130 by shutting down one or more loads of the auxiliary system, such as a compressor, pump, heater, or other electrical components of the temperature control system, or by adjusting the operating mode of one or more such loads (e.g., placing one or more such loads into a low power operating mode or a low power operating mode). In this way, the current required by the auxiliary system 130 can be reduced, thereby reducing the power demand on the alternator 114.

[0068] If the alternator 114 is still unable to supply the required power to the auxiliary systems despite the reduced power demand of the auxiliary systems 130, or if it is impossible or undesirable to reduce the power demand of the auxiliary systems 130 (for example, if doing so would cause the temperature within the load space of the host vehicle to increase above or otherwise deviate from a set point temperature), the controller 150 may couple the auxiliary battery 136 to one or more loads of the auxiliary systems 130 to supply the required power or to compensate for the difference between the power supplied to the auxiliary systems 130 by the alternator 114 and the power demand of the auxiliary systems 130. When the auxiliary battery 136 is coupled to one or more loads of the auxiliary systems 130 in this manner, the one or more loads of the auxiliary systems 130 are thereby at least partially powered by the auxiliary battery 136.

[0069] Figure 4 is with Figure 2 The power curve 202 shown in FIG. Figure 3 A graphical illustration of the operations of method 300 is provided.

[0070] Initially, at a first point 402, the power demand of the auxiliary system 130 is below the power curve 202, and thus the output voltage Valt of the alternator 114 is equal to Vnom. Therefore, at step 306, the controller 150 determines that the alternator output voltage Valt is greater than the threshold value Vth, and thus the controller 150 moves to step 308, where, as described above, the controller 150 increases the power demand of the auxiliary system 130 to a second point 404. The controller 150 then returns to step 304 of the method 300.

[0071] At the second point 404, the power demand of the auxiliary system 130 is on the power curve 202, so the output voltage Valt of the alternator 114 is still equal to Vnom. Therefore, at step 310, the controller 150 determines that the alternator output voltage Valt is equal to the threshold value Vth, so the controller 150 moves to step 312, as described above, at which point the controller 150 maintains the power demand of the auxiliary system 130 and returns to step 304 of the method 300.

[0072] Between the second point 404 and the third point 406, the host vehicle incorporating the auxiliary system 130 accelerates, causing an increase in the speed of the alternator 114. Consequently, the current that can be supplied by the alternator 114 increases.

[0073] Point 406 is below the power curve 202, so the alternator output voltage remains at Vnom. At step 306, the controller 150 determines that the alternator output voltage Valt is greater than the threshold value Vth, so the controller 150 moves to step 308, where, as described above, the controller 150 increases the power demand of the auxiliary system 130 to the fourth point 408. The controller 150 then returns to step 304 of the method 300.

[0074] Between the fourth point 408 and the fifth point 410, the host vehicle decelerates, and thus the output current that can be supplied by the alternator 114 decreases. (Since the power demand of the auxiliary systems 130 remains at the level set at point 406), the output voltage Valt of the alternator 114 drops below the threshold value Vth. Therefore, at step 310, the controller determines that the alternator output voltage Valt is less than the threshold value Vth, and thus reduces the power demand of the auxiliary systems 310 as described above, until the reduced power demand causes the alternator output voltage Valt to increase to the threshold value Vth at point 412. Alternatively, the controller 150 can use the auxiliary battery 136 to compensate for the difference between the power demand of the auxiliary systems 310 and the power that can be supplied by the alternator 114, thereby reducing the power demand of the auxiliary systems 310 to point 412, at which point the reduced power demand causes the alternator output voltage Valt to return to the threshold value Vth. In another alternative, the controller 150 may both reduce the power demand of the auxiliary systems as described above and use the auxiliary battery 136 to make up the difference between the reduced power demand of the auxiliary systems 310 and the power that the alternator 114 can supply.

[0075] As will be apparent from the above discussion, the systems and methods of the present disclosure allow the power requirements of the auxiliary systems 130 to be managed and controlled to ensure that the required power can be supplied by the AC generator 114 alone, or by the AC generator in combination with the auxiliary battery 136, without drawing power from the vehicle battery 118.

[0076] It is contemplated that the above-described systems and methods will be used in conjunction with conventional vehicle alternators, such as Lundell-type alternators, which are rated for a single nominal output voltage, Vnom.

[0077] However, in variations of the present disclosure, a buck-boost regulator may be coupled to the alternator 114 to provide a controllable output voltage to the auxiliary system 130 as needed or appropriate, as will now be described with reference to FIG. Figure 5 Provide a description.

[0078] Figure 5is a schematic diagram showing relevant elements of a host vehicle (eg, a truck) and elements of an auxiliary system that draws power from the host vehicle's alternator or from an auxiliary battery of the auxiliary system. Figure 1 and Figure 5 Like elements are denoted by like reference numerals and, for the sake of clarity and brevity, these elements will not be described again in detail herein.

[0079] like Figure 1 As shown in Figure 5 In FIG, elements of the host vehicle are shown within box 110 , while elements of the auxiliary system are shown within box 130 .

[0080] and Figure 1 The arrangement shown is opposite, Figure 5 In the arrangement shown, the output terminals of the alternator 114 are not coupled to the battery bus 120. Instead, the output terminals of the alternator 114 are coupled to a buck-boost converter 510, which is configured to receive the output of the alternator 114 and generate a plurality (three in the illustrated example) of buck-boost converter output voltages. Thus, the buck-boost converter 510 has a first output 512 that supplies a first output voltage to power a buck-boost controller 520, which operates to control the operation of the buck-boost converter 510. The first output 512 may also supply power to one or more other low-voltage electrical systems of the host vehicle.

[0081] The buck-boost converter 510 has a second output terminal 514 for supplying a second output voltage. The second output terminal 514 is coupled to the first power converter 132 of the auxiliary system 130, which operates to provide power to one or more high-voltage loads of the auxiliary system 130, as described above with reference to FIG. Figure 1 described.

[0082] Buck-boost converter 510 has a third output 516 that is coupled to vehicle battery 118 and operates to provide a suitable voltage and / or current to charge vehicle battery 118 .

[0083] Buck-boost converter 510 has another output 518 that provides a field driver control signal to control the field strength in the rotor of alternator 114 .

[0084] Buck-boost converter 510 receives control signals from buck-boost controller 520 that control various aspects of the operation of buck-boost converter 510 , such as the voltage output at each of the first, second, and third output terminals 512 - 516 .

[0085] The use of buck-boost converter 510 allows for the generation of multiple different output voltages from the electrical output of alternator 114. Thus, appropriate voltages can be generated to power different loads, which can improve efficiency, for example, by reducing resistive losses. For example, the 48-volt power provided by buck-boost converter 510 to auxiliary systems 130 configured to operate from a 48-volt power source can be coupled to components of auxiliary systems 130 using smaller-gauge wiring than would be required to provide the same amount of power using a 12-volt power source. Using this smaller-gauge wiring also reduces weight.

[0086] In addition, the output voltage at the output terminal (e.g., third output terminal 516) of the buck-boost converter for providing charging power to the vehicle battery 118 (or vehicle battery pack) can be adapted according to battery parameters such as temperature, charge state, and other parameters to improve charging efficiency and battery reliability.

[0087] Furthermore, because the buck-boost converter 510 controls the magnetic field in the rotor of the alternator 114, the amount of load applied by the alternator 114 to the vehicle's engine 112 can be adjusted by adjusting the magnetic field in the rotor. Thus, the buck-boost controller 520 can be coupled to other systems of the host vehicle 110 to receive relevant information from such systems and to adjust the load applied by the alternator 114 to the engine 112 accordingly by appropriately adjusting the magnetic field driver control signal output by the buck-boost converter 510. For example, it may be necessary to control the load applied by the alternator 114 to the engine 112 to meet emission requirements, engine speed requirements, or to improve overall system efficiency. In the event that it is necessary to control the load applied by the alternator 114 to the engine 112, the controller 150 may (temporarily) cease executing the above-mentioned reference control. Figure 3 The described maximum power point tracking method allows the load on the engine 112 to be adjusted via the field driver control signal output by the buck-boost converter 510 .

[0088] In the case where a buck-boost converter 510 is provided, the above-mentioned reference voltage can be implemented. Figure 3 A method is described to manage the power drawn by the auxiliary system 130 from the alternator 114 to ensure that the auxiliary system 130 draws the maximum available power from the alternator 114 for a given alternator output voltage, without drawing power from the vehicle battery 118. In this arrangement, the controller 150 monitors the voltage supplied by the buck-boost converter 510 to the first power converter 132, for example, via the second output terminal 514 of the buck-boost converter, rather than monitoring the output voltage of the alternator 114.

[0089] Despite Figure 5 The buck-boost converter 510 and buck-boost controller 520 are shown as part of the host vehicle 110, but it will be appreciated that the buck-boost converter 510 and buck-boost controller 520 may alternatively be provided as part of the auxiliary system 530 where appropriate.

[0090] It should be noted that where a buck-boost regulator is provided, the above referenced Figure 3 The method described above is used to extract the maximum available power from the alternator 114 (for a given alternator output voltage). Figure 3 In cases where the maximum power point tracking method is incompatible with the use of a buck-boost regulator, for example where the field driver control signal output by the buck-boost converter 510 is used to control the magnetic field in the rotor of the alternator 114, the controller 150 may (temporarily) stop performing the maximum power point tracking method.

[0091] It should be noted that the above-mentioned embodiments illustrate rather than limit the present disclosure, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim, and "a" or "an" does not exclude a plurality. Any reference signs in a claim should not be construed as limiting its scope.

Claims

1. A system for managing power drawn from a vehicle alternator to power auxiliary systems, the system comprising: The controller is configured to: determining an output voltage of the vehicle alternator; comparing an output voltage of the vehicle alternator to a threshold value; as well as The power required by the auxiliary systems from the vehicle alternator is adjusted based on the comparison result to ensure that the power required by the auxiliary systems can be supplied without drawing power from the vehicle's battery. 2 . The system of claim 1 , wherein the controller is configured to adjust the current drawn by the auxiliary system to adjust the power required by the auxiliary system. 3 . The system of claim 1 , wherein the controller is configured to cut off one or more loads of the auxiliary system to adjust the power required by the auxiliary system. 4 . The system of claim 1 , wherein the controller is configured to adjust an operating mode of one or more loads of the auxiliary system to adjust power required by the auxiliary system.

5. The system of claim 1 , wherein the controller is configured to: increasing the power required by the auxiliary system if the output voltage of the vehicle alternator is greater than the threshold; If the output voltage of the vehicle alternator is less than the threshold, reducing the power required by the auxiliary system; or If the output voltage of the vehicle alternator is equal to the threshold, the power required by the auxiliary system is maintained.

6. The system of claim 1, wherein the system further comprises an auxiliary battery for powering the auxiliary system.

7. The system of claim 6, wherein the controller is configured to: If the output voltage of the vehicle alternator is greater than the threshold, the power supply to the auxiliary battery is adjusted to charge the auxiliary battery.

8. The system of claim 6, wherein the controller is configured to: If the output voltage of the vehicle alternator is below the threshold, coupling the auxiliary battery to one or more loads of the auxiliary system such that the one or more loads of the auxiliary system are at least partially powered by the auxiliary battery.

9. The system of claim 1, wherein the controller comprises a proportional-integral controller.

10. The system of claim 1, further comprising a buck-boost converter coupled to an output of the vehicle alternator and operative to provide a power supply to the auxiliary system.

11. A method of managing power drawn from a vehicle alternator to power an auxiliary system, the method comprising: determining an output voltage of the vehicle alternator; comparing an output voltage of the vehicle alternator to a threshold value; as well as The power required by the auxiliary systems from the vehicle alternator is adjusted based on the comparison result to ensure that the power required by the auxiliary systems can be supplied without drawing power from the vehicle's battery. 12 . The method of claim 11 , wherein adjusting the power required by the auxiliary system comprises adjusting the current drawn by the auxiliary system. 13 . The method of claim 11 , wherein adjusting the power required by the auxiliary system comprises shutting off one or more loads of the auxiliary system. 14 . The method of claim 11 , wherein adjusting the power required by the auxiliary system comprises adjusting an operating mode of one or more loads of the auxiliary system.

15. The method of claim 11, wherein adjusting the power required by the auxiliary system comprises: increasing the power required by the auxiliary system if the output voltage of the vehicle alternator is greater than the threshold; reducing the power required by the auxiliary system if the output voltage of the vehicle alternator is less than the threshold; or If the output voltage of the vehicle alternator is equal to the threshold, the power required by the auxiliary system is maintained.

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