Auxiliary power system and method

Abstract

The present invention relates to auxiliary power systems and methods. An auxiliary power system includes an auxiliary power module having a primary power switch, a transformer, and a secondary rectifier. The primary power switch is electrically connected to a high voltage bus, and the secondary rectifier is electrically connected to a low voltage bus. A peak detector is coupled to the high voltage bus. A controller is in electrical communication with the peak detector circuit and is operatively connected to the primary power switch. The controller dynamically monitors a ripple voltage of the high voltage bus through the peak detector circuit, compares the monitored voltage to a maximum threshold voltage, and disables the plurality of primary power switches when the ripple voltage of the high voltage bus is greater than the maximum threshold voltage, and reactivates the primary power switch when the ripple voltage of the high voltage bus is less than the maximum threshold voltage.

Description

BACKGROUND

[0001] An accessory power module is a device that is capable of converting high voltage DC electrical power to low voltage DC electrical power to provide electrical power to low voltage electrically powered devices. When employed on a vehicle, examples of low voltage electrically powered devices include entertainment systems, lighting, power windows, controls, etc.

[0002] The accessory power module receives high voltage DC electrical power from a high voltage bus coupled to a DC power source. In some applications, the DC power source is configured to provide high voltage electrical power to power one or more electric machines through a switching inverter. The electric machine can be a motor / generator that generates traction torque in one operating state and generates electrical power in a second operating state, where the switching inverter operates to convert electrical power from a DC state to an AC waveform in the traction torque state and from the AC waveform to the DC state in the generating state. This operation can create voltage ripple in the electrical power on the high voltage bus, which the accessory power module experiences.

[0003] The voltage ripple can damage or shorten the useful life of the power transistors of the accessory power module when the peak amplitude of the voltage ripple exceeds the maximum voltage design level of the power transistors.

[0004] There is a need for systems, methods, and / or devices that understand the amplitude of the voltage ripple and dynamically control the accessory power module when the amplitude of the voltage ripple exceeds the maximum voltage design level of the power transistors. SUMMARY

[0005] The concepts described herein provide methods, systems, and devices for controlling the operation of an accessory power module that includes a DC-DC electrical power converter that is an element of a high voltage electrical power system. The accessory power module is controlled in a manner that prevents, avoids, or otherwise excludes exposing high voltage electronic power switches, such as power MOSFET switches, to dynamically varying electrical power levels that are greater than a threshold voltage level. The threshold voltage level is based on the maximum rated voltage of the electronic power switches. The electrical power levels that are greater than the threshold voltage level can be transient voltage levels caused by voltage ripple induced by another device electrically connected to the high voltage electrical power system, such as a power inverter. The benefit of the peak detector method and overvoltage shutdown system compared to known re-filtration methods is that the peak ripple and AC gain of the input filter are directly measured. Other methods, such as the re-filtration method, require the overvoltage shutdown threshold to be based on the worst case values of the peak ripple and AC gain of the high voltage input filter.

[0006] One aspect of the disclosure includes an accessory power system electrically coupled to a high voltage input filter downstream of a high voltage DC power bus and a low voltage output filter upstream of a low voltage DC bus. The accessory power system includes an accessory power module having a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers. The plurality of primary power switches are electrically connected to the high voltage input filter downstream of the high voltage bus and the plurality of secondary rectifiers are electrically connected to the low voltage output filter upstream of the low voltage bus. A peak detector is coupled to the high voltage input filter downstream of the high voltage bus. A controller is in electrical communication with the peak detector circuit and is operatively connected to the plurality of primary power switches. The controller includes a set of instructions executable to dynamically monitor, by the peak detector circuit, a ripple voltage of the high voltage bus multiplied by an AC gain of the high voltage input filter, compare the monitored voltage to a maximum threshold voltage, disable the plurality of primary power switches when the monitored voltage is greater than the maximum threshold voltage, and reactivate the plurality of primary power switches when the monitored voltage of the high voltage bus is less than the maximum threshold voltage.

[0007] Another aspect of the disclosure includes that the peak detector is a circuit having a series forward biased diode disposed upstream of a resistor and a capacitor disposed in parallel between the diode and ground, and wherein an RC time constant of the resistor and capacitor is determined based on a frequency and amplitude of the ripple voltage and a target recovery time.

[0008] Another aspect of the disclosure includes that the target recovery time is determined based on the frequency and amplitude of the ripple voltage and a capacity of the low voltage battery.

[0009] Another aspect of the disclosure includes that the circuit of the peak detector is implemented as a software routine.

[0010] Another aspect of the disclosure includes that the circuit of the peak detector is implemented as a plurality of electrical components.

[0011] Another aspect of the disclosure includes that the plurality of primary power switches are power MOSFET switches, wherein the maximum threshold voltage is determined based on a maximum rated voltage of the power MOSFET switches.

[0012] Another aspect of the disclosure includes that the maximum rated voltage of the power MOSFET switches is a maximum drain to source voltage.

[0013] Another aspect of the present disclosure includes an electrical system having: a DC power source electrically connected to a power inverter via a high voltage electrical bus; an auxiliary power module electrically coupled to a high voltage input filter downstream of the high voltage bus; an overvoltage shutdown system including a peak detector coupled to the high voltage input filter downstream of the high voltage bus; a comparator; and a controller. The auxiliary power module is a DC-DC electrical power converter having a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers. The plurality of primary power switches are electrically connected to the high voltage input filter downstream of the high voltage bus. The controller is in electrical communication with the peak detector circuit and is operatively connected to the plurality of primary power switches. The controller includes a set of instructions executable to dynamically monitor, by the peak detector circuit, a ripple voltage on the high voltage bus multiplied by an AC gain of the high voltage input filter; compare, by the comparator, the monitored voltage to a maximum threshold voltage; and disable the plurality of primary power switches when the ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter is greater than the maximum threshold voltage.

[0014] Another aspect of the present disclosure includes: the peak detector is a circuit having a series forward biased diode disposed upstream of a resistor and a capacitor disposed in parallel between the diode ground, wherein an RC time constant of the resistor and capacitor is determined based on a frequency and amplitude of the ripple voltage and a target recovery time.

[0015] Another aspect of the present disclosure includes: an output signal from the peak detector is a first input to the comparator, and a maximum threshold voltage is a second input to the comparator, and an output of the comparator is operatively connected to the plurality of primary power switches of the auxiliary power module.

[0016] Another aspect of the present disclosure includes: a method for controlling an auxiliary power module including a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers, wherein the plurality of primary power switches are electrically connected to a high voltage input filter downstream of a high voltage bus. The method includes dynamically monitoring, by a peak detector circuit, a ripple voltage on the high voltage bus multiplied by an AC gain of the high voltage input filter; comparing the monitored voltage to a maximum threshold voltage for the plurality of primary power switches; and disabling the plurality of primary power switches when the monitored voltage is greater than the maximum threshold voltage.

[0017] The present invention also includes the following technical solutions.

[0018] Solution 1. An auxiliary power system electrically coupled to a high voltage input filter downstream of a high voltage bus, the auxiliary power system comprising:

[0019] an accessory power module comprising a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers; wherein the plurality of primary power switches are electrically connected to the high voltage input filter downstream of the high voltage bus, and wherein the plurality of secondary rectifiers are electrically connected to the low voltage output filter downstream of the low voltage bus;

[0020] a peak detector coupled to the high voltage input filter downstream of the high voltage bus; and

[0021] a controller in communication with the peak detector and operatively connected to the plurality of primary power switches;

[0022] the controller comprises a set of instructions executable to:

[0023] dynamically monitor, by the peak detector, a ripple voltage of the high voltage bus multiplied by an AC gain of the high voltage input filter;

[0024] compare the monitored voltage to a maximum threshold voltage;

[0025] disable the plurality of primary power switches when the monitored voltage is greater than the maximum threshold voltage; and

[0026] reactivate the plurality of primary power switches when the monitored voltage is less than the maximum threshold voltage.

[0027] Scheme 2. The accessory power system of Scheme 1, wherein the peak detector comprises a circuit having a series forward-biased diode disposed upstream of a resistor and a capacitor, the resistor and the capacitor being disposed in parallel between the diode and ground, and wherein an RC time constant of the resistor and the capacitor is determined based on a frequency and an amplitude of the ripple voltage and a target recovery time.

[0028] Scheme 3. The accessory power system of Scheme 2, wherein the target recovery time is determined based on a DC component of the high voltage bus in combination with the frequency and the amplitude of the ripple voltage and a capacity of a low voltage battery electrically connected to the low voltage output filter downstream of the low voltage bus.

[0029] Scheme 4. The accessory power system of Scheme 2, wherein the circuit of the peak detector is implemented as a software routine.

[0030] Scheme 5. The accessory power system of Scheme 2, wherein the circuit of the peak detector is implemented as a plurality of electrical components.

[0031] Scheme 6. The accessory power system of Scheme 1, wherein the plurality of primary power switches comprises power MOSFET switches, and wherein the maximum threshold voltage is determined based on a maximum rated voltage of the power MOSFET switches.

[0032] Scheme 7. The accessory power system of Scheme 6, wherein the maximum rated voltage of the power MOSFET switches comprises a maximum drain-source voltage.

[0033] Scheme 8. An electrical system comprising:

[0034] a DC power source electrically connected to a power inverter via a high voltage electrical bus;

[0035] an accessory power module electrically coupled to a high voltage input filter downstream of the high voltage bus; and

[0036] an overvoltage shutdown system comprising a peak detector, a comparator, and a controller coupled to the high voltage input filter downstream of the high voltage bus;

[0037] wherein the accessory power module comprises a DC-DC electrical power converter having a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers;

[0038] wherein the plurality of primary power switches are electrically connected to the high voltage input filter downstream of the high voltage bus;

[0039] wherein the accessory power module is coupled to a low voltage electrical power bus;

[0040] wherein the controller is in communication with the peak detector and is operatively connected to the plurality of primary power switches;

[0041] the controller comprises a set of instructions executable to:

[0042] dynamically monitor, by the peak detector, a ripple voltage on the high voltage bus multiplied by an AC gain of the high voltage input filter;

[0043] compare, by the comparator, the voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter to a maximum threshold voltage; and

[0044] disable the plurality of primary power switches when the monitored voltage of the high voltage bus is greater than the maximum threshold voltage.

[0045] Scheme 9. The electrical system according to Scheme 8, wherein the peak detector comprises a circuit having a series forward-biased diode disposed upstream of a resistor and a capacitor disposed in parallel between the diode and ground, and wherein an RC time constant of the resistor and the capacitor is determined based on a frequency and amplitude of the ripple voltage and a target recovery time.

[0046] Scheme 10. The electrical system according to Scheme 9, wherein the target recovery time is determined based on the frequency and amplitude of the ripple voltage and a storage capacity of a low-voltage battery of the low-voltage power bus.

[0047] Scheme 11. The electrical system according to Scheme 9, wherein the peak detector is implemented as a software routine.

[0048] Scheme 12. The electrical system according to Scheme 9, wherein the peak detector is implemented as an electrical component circuit.

[0049] Scheme 13. The electrical system according to Scheme 8, wherein an output signal from the peak detector is a first input to the comparator, wherein the maximum threshold voltage is a second input to the comparator, and wherein an output of the comparator is operatively connected to the plurality of primary power switches of the accessory power module.

[0050] Scheme 14. The electrical system according to Scheme 8, wherein the plurality of primary power switches comprises power MOSFET switches, and wherein the maximum threshold voltage is determined based on a maximum rated voltage of the power MOSFET switches.

[0051] Scheme 15. The electrical system according to Scheme 14, wherein the maximum rated voltage of the power MOSFET switches comprises a maximum drain-source voltage.

[0052] Scheme 16. The electrical system according to Scheme 8, wherein the set of instructions are executable to reactivate the plurality of primary power switches when the ripple voltage on the high-voltage bus multiplied by the AC gain of the high-voltage input filter is less than the maximum threshold voltage.

[0053] Scheme 17. A method for controlling an accessory power module, the accessory power module comprising a DC-DC electrical power converter having a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers, wherein the plurality of primary power switches are electrically connected to a high-voltage input filter downstream of a high-voltage bus, the method comprising:

[0054] dynamically monitoring, by a peak detector circuit, a ripple voltage on the high voltage bus multiplied by an AC gain of the high voltage input filter;

[0055] comparing the ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter to a maximum threshold voltage of the plurality of primary power switches; and

[0056] disabling the plurality of primary power switches when the ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter is greater than the maximum threshold voltage.

[0057] Scheme 18. The method of Scheme 17, further comprising reactivating the plurality of primary power switches when the ripple voltage of the high voltage bus multiplied by the AC gain of the high voltage input filter is less than the maximum threshold voltage.

[0058] Scheme 19. The method of Scheme 17, wherein the plurality of primary power switches comprises power MOSFET switches, and wherein the maximum threshold voltage is determined based on a maximum rated voltage of the power MOSFET switches.

[0059] Scheme 20. The method of Scheme 19, wherein the maximum rated voltage of the power MOSFET switches comprises a maximum drain-source voltage.

[0060] The above summary is not intended to represent each and every possible embodiment of the disclosure or every aspect thereof. Rather, the foregoing summary is intended to exemplify some of the novel aspects and features of the disclosure herein. The above features and advantages, and other features and advantages of the present disclosure are readily apparent from the following detailed description of representative embodiments and modes of the disclosure, when taken in connection with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0061] One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

[0062] Figure 1 schematically illustrates a high voltage electrical power system according to the present disclosure including an accessory power module having a DC-DC electrical power converter.

[0063] Figure 2 schematically illustrates a peak detector circuit according to the present disclosure.

[0064] Figure 3 graphically illustrates voltage ripple that can occur on a high voltage power bus and operation of an embodiment of a peak detector circuit according to the present disclosure.

[0065] Figure 4Graphical illustrations of voltage ripple levels that can occur on a high voltage power bus and operation of an embodiment of a peak detector circuit according to the present disclosure are illustrated.

[0066] Figure 5 A process for controlling operation of an embodiment of a high voltage electrical power system including an accessory power module having a DC-DC electrical power converter according to the present disclosure is schematically illustrated.

[0067] The drawings are not necessarily to scale and can present a somewhat simplified representation of various preferred features of the present disclosure as disclosed herein, for example including specific dimensions, orientations, locations and shapes. Details associated with such features will be determined in part by the particular intended application and use environment. DETAILED DESCRIPTION

[0068] As described and illustrated herein, components of the disclosed embodiments can be arranged and designed in a wide variety of different configurations. Therefore, the following detailed description is not intended to limit the scope of the present disclosure as claimed, but is merely representative of possible embodiments. Additionally, while numerous specific details are set forth in the following description to provide a thorough understanding of the embodiments disclosed herein, certain embodiments can be practiced without some or all of these details. Moreover, for the purpose of clarity, certain technical material that is understood in the technical fields relating to the present disclosure is not described in detail, in order to avoid obscuring the present disclosure.

[0069] Furthermore, the drawings are in simplified form and are not to precise scale. For ease of comprehension and reference, directional terms, such as top, bottom, left, right, upper, lower, above, below, beneath, rear, and front, can be used with respect to the drawings. These and similar terms are not to be interpreted as limiting the scope of the present disclosure. Furthermore, the present disclosure can be practiced in the absence of one or more of the specific elements disclosed herein.

[0070] The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in this document. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0071] As used herein, the term "system" can refer to one or a combination of mechanical and electrical actuators, sensors, controllers, application specific integrated circuits (ASICs), combinational logic circuits, software, firmware, and / or other components arranged to provide the described functionality.

[0072] Furthermore, exemplary embodiments herein can be described in terms of functional and / or logical block components and various processing steps. It should be appreciated that such block components can be realized by any number of mechanical and / or electrical hardware components, software components, firmware components, and / or any number of combinations thereof. For example, the embodiments can employ mechanical and electrical components, an integrated circuit, a memory element, a digital signal processor, a logic element, a look-up table, and / or the like, which can be configured to perform various functions. Furthermore, one skilled in the art will appreciate that exemplary embodiments can be practiced with any number of mechanical and / or electrical systems, and that the system described herein is merely exemplary embodiments of possible implementations. For the sake of brevity, known components and techniques and other functional aspects of the systems (and the individual operating components of the systems) can not be described in detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternatives or additions can be made within the scope of the various embodiments.

[0073] As used herein, the term "upstream" and related terms refer to elements relative to an indicated location toward the origin of a flow stream, and the term "downstream" and related terms refer to elements relative to an indicated location away from the origin of a flow stream.

[0074] The use of numerals such as first, second, and third does not necessarily imply an ordinal sequence, but rather can distinguish multiple instances of an action or structure.

[0075] The phrase "operatively connected" is a general descriptive term that reflects the functional relationship between claimed elements that are connected in some manner to perform a specified function.

[0076] Referring now to the drawings, which are provided for purposes of illustration and not limitation, Figure 1 An electrical system 100 is schematically illustrated that includes a rechargeable electrical energy storage system (RESS) 10, a high voltage DC power bus 15, a power inverter 12, and an ancillary power system 20. In one embodiment, the electrical system 100 can be arranged as part of an electrical drive system on a vehicle, although the concepts described herein are not limited to this. In this case, the vehicle can include, but is not limited to, a mobile platform in the form of a commercial vehicle, an industrial vehicle, an agricultural vehicle, a passenger vehicle, an aircraft, a watercraft, a train, an all-terrain vehicle, a personal mobility device, a robot, and the like for purposes of the present disclosure. Alternatively, the electrical system 100 can be arranged to provide torque to a stationary system. The electrical system 100 can take many different forms and have additional components.

[0077] In one embodiment, the RESS 10 is a rechargeable DC power source and can include battery cells of various chemical compositions, such as lithium metal based devices. The RESS 10 supplies high voltage DC electrical power to a high voltage DC power bus 15, which is connected to the power inverter 12 and ancillary power systems 20 through a high voltage input filter 18. High voltage DC electrical power refers to a system nominally at 300V, a system nominally at 480V, or another DC voltage system. The high voltage DC power bus 15 can contain significant amounts of AC voltage ripple that can be generated by the operation of the power inverter 12 under certain operating conditions, such as regenerative braking, uncontrolled power generation, etc.

[0078] The power inverter (PIM) 12 is a multi-phase inverter that converts DC electrical power to AC electrical power for controlling the operation of an electric machine, such as a motor / generator. In some embodiments, the power inverter 12 can be part of a power inverter module that powers a rotating electric machine to provide traction power for an electric vehicle. A single power inverter 12 is illustrated. It is to be appreciated that there can be multiple power inverters that are supplied with high voltage DC electrical power from the high voltage DC power bus 15.

[0079] The power inverter 12 is configured with control circuitry that includes power transistors, such as IGBTs, for converting high voltage DC electrical power to high voltage AC electrical power and vice versa. In one embodiment, the power inverter 12 can employ pulse width modulation (PWM) control of the IGBTs to convert stored DC electrical power from the rechargeable energy storage unit 10 to AC electrical power to drive a rotating electric machine to produce torque. Similarly, the power inverter 12 can convert mechanical power delivered to a rotating electric machine to DC electrical power to generate electrical energy that can be stored in the rechargeable energy storage unit 10, including as part of a regenerative braking control strategy. The power inverter 12 receives motor control commands and controls the inverter state to provide motor drive and regenerative braking functions.

[0080] The accessory power system 20 includes an accessory power module 30 and an overvoltage system 50. The accessory power module 30 is a DC-DC electrical power converter that includes a plurality of primary power switches 32, a transformer 34, and a plurality of secondary rectifiers 36. An accessory power module controller 60 is operatively connected to the plurality of primary power switches 32 to control their activation and deactivation. The accessory power module controller 60 is also capable of disabling the plurality of primary power switches 32. In one embodiment, the plurality of primary power switches 32 are power MOSFET switches that have a maximum rated voltage. In one embodiment, the maximum rated voltage is a maximum drain-to-source voltage. As appreciated by those skilled in the art, operating a power MOSFET switch at a voltage level greater than its maximum rated voltage can significantly reduce its useful life.

[0081] The plurality of primary power switches 32 are electrically connected to a high voltage input filter 18 downstream of the high voltage DC power bus 15. The plurality of secondary rectifiers 36 are electrically connected to a low voltage output filter 39 that is deployed in-line to filter electrical noise upstream of a low voltage electrical power bus 38. The accessory power module 30 converts high voltage DC electrical power from the high voltage DC power bus 15 to low voltage DC electrical power that is distributed via the low voltage electrical power bus 38. When employed on a vehicle, the low voltage electrical power bus 38 supplies low voltage DC electrical power to one or more low voltage devices and systems 40 on the vehicle, including, for example, a low voltage battery, power windows, HVAC fans, seats, a starter, interior and exterior lighting, and an ignition system. In one embodiment, the low voltage DC electrical power is a voltage level of nominally 12V. Alternatively, the low voltage DC electrical power can be another voltage level, such as 24V, or 36V, or 48V. Sensors and other monitoring elements (not shown) can be arranged to monitor electrical parameters (e.g., voltage, current) at various locations, as well as mechanical parameters (e.g., speed) at various other locations.

[0082] In one embodiment, the overvoltage system 50 includes a peak detector 52 and an overvoltage shutdown (OVSD) comparator 54 coupled to the high voltage input filter 18 downstream of the high voltage DC power bus 15. In one embodiment, the operation of the elements of the overvoltage system 50 is controlled by the accessory power module controller 60.

[0083] The accessory power module controller 60 monitors inputs from the overvoltage system 50 and controls the activation and deactivation of the plurality of primary power switches 32. The overvoltage system 50 operates to protect power devices, such as the primary power switches 32 of the accessory power module 30, in the event that there is high voltage electrical power on the high voltage DC power bus 15, such as AC ripple resulting from the operation of the power inverter 12.

[0084] For reference Figure 1 As shown, the peak detector 52 is a circuit having a series forward-biased diode 62 disposed upstream of resistor 64 and capacitor 66, which are connected in parallel between the cathode of diode 62 and ground 68. The RC time constant and corresponding amplitude of resistor 64 and capacitor 66 are determined based on the frequency and amplitude of the ripple voltage and the target recovery time. In one embodiment, the circuitry of peak detector 52 is implemented as a software routine in an auxiliary power module controller 60. Alternatively, the circuitry of peak detector 52 is implemented as multiple electrical components disposed on a circuit board. In any configuration, the voltage output from peak detector 52 is provided as an input to OVSD comparator 54.

[0085] The peak detector method captures both the DC and AC components of the bus voltage, as well as the AC gain of the high-voltage input filter. The capacitor rapidly charges the OVSD signal during positive excursion, and the diode is reverse-biased during negative excursion. OVSD recovery can be controlled by adjusting the RC time constant.

[0086] The OVSD comparator 54 has inputs to the voltage output from the peak detector 52 and a reference threshold voltage 56, and has a discrete output of either "1" or "0", which is provided as input 55 to the auxiliary power module controller 60 to control the plurality of primary power switches 32. When the voltage output from the peak detector 52 is less than the reference threshold voltage 56, the OVSD comparator 54 produces a discrete output of "0", which allows the auxiliary power module controller 60 to control the plurality of primary power switches 32 to operate in the intended manner. When the voltage output from the peak detector 52 is greater than the reference threshold voltage 56, the OVSD comparator 54 produces a discrete output of "1", which causes the auxiliary power module controller 60 to disable the plurality of primary power switches 32, thereby preventing overvoltage conditions.

[0087] The reference threshold voltage 56 is a calibrable value and is set to not exceed the maximum rated voltage of the power MOSFET switch, which in one embodiment is the maximum drain-to-source voltage.

[0088] Primary power switch 32 is disabled to prevent damage exceeding the component voltage breakdown rating. Disabling primary power switch 32 increases voltage margin by eliminating overshoot that occurs during on- and off-state.

[0089] The target recovery time is determined based on the DC component of the high-voltage source combined with the frequency and amplitude of the ripple voltage and the capacity of the low-voltage battery, which is part of the low-voltage device and system 40 that is electrically connected downstream of the low-voltage output filter 39 to the low-voltage bus 38.

[0090] The reference threshold voltage 56 used with the peak detector method includes sufficient margin to protect against worst case switching overshoot. This is in contrast to the reference threshold voltage used with known re-filtering methods which include sufficient margin to protect against worst case switching overshoot, PIM ripple, and AC gain of the associated power module high voltage filter.

[0091] The peak detector 52 detects the DC and AC components of the bus voltage 15 and the AC gain of the high voltage input filter 18. If the detected voltage exceeds the threshold set by the associated power module design, the associated power module controller will signal to shut down the associated power module. This action serves to extend the operating range through voltage measurements with higher fidelity as compared to existing strategies that use low bandwidth measurements to prevent nuisance trips.

[0092] The term "controller" and related terms, such as microcontroller, control, control unit, processor, etc., refer to one or a combination of the following: an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an electronic circuit, a central processing unit, such as a microprocessor, and associated non-transitory memory components in the form of memory and storage devices (read only, programmable read only, random access, hard drives, etc.). The non-transitory memory components are capable of storing machine readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning, buffering circuits, and other components that are accessible and executable by one or more processors to provide the described functionality. Input / output circuits and devices include analog / digital converters and associated devices that monitor inputs from sensors, where such inputs are monitored at a preset sampling frequency or in response to a triggering event. Software, firmware, programs, instructions, control routines, code, algorithms, and like terms mean sets of controller executable instructions including calibration and lookup tables. Each controller executes control routines to provide the desired functionality. The routines can be executed at regular intervals, such as every 100 microseconds during ongoing operation. Alternatively, the routines can be executed in response to the occurrence of a triggering event. Communication between controllers, actuators, and / or sensors can be achieved using direct wired point-to-point links, networked communication bus links, wireless links, or another communication link. Communication includes the exchange of data signals, such as including electrical signals via conductive media, electromagnetic signals via air, optical signals via optical waveguides, etc. The data signals can include discrete, analog, and / or digitized analog signals representative of inputs from sensors, actuator commands, and communications between controllers.

[0093] Figure 3The time-based voltage ripple 315 that can occur on the high voltage DC power bus 15 is graphically illustrated multiplied by the AC gain of the high voltage input filter 18 supplying electrical power to an embodiment of the auxiliary power system 20 described herein. Also depicted is the signal output from an embodiment of the peak detector 52 as shown by line 320. The voltage ripple 315 is the combination of the HV bus maximum DC voltage 312, the HV bus voltage ripple, and the AC gain of the high voltage input filter 18. The signal output from the peak detector circuit 50 (line 320) includes a maximum voltage 322 and a decay voltage 324, which is associated with OVSD recovery, which can be controlled by adjusting the RC time of the peak detector 52, i.e., adjusting the resistor 64 and / or the capacitor 66. This arrangement eliminates the need to introduce hysteresis into the operation of the overvoltage circuit 50 or the controller 60.

[0094] Figure 4 The voltage ripple levels that can occur on a high voltage power bus and the operation of an embodiment of the peak detector circuit according to the present disclosure are graphically illustrated. The horizontal line includes a nominal voltage level 401 on the high voltage DC power bus 15 and an OVSD threshold voltage 402. Line 410 represents a voltage level including a high level of voltage ripple 415 having a peak 412 and a decay 414, both of which are greater than the OVSD threshold voltage 402, which causes the auxiliary power module controller 60 to disable operation of the plurality of primary power switches 32. Line 420 represents a voltage level including a medium or light level of voltage ripple 425 having a peak 422 and a decay 424, both of which are less than the OVSD threshold voltage 402. In this case, the auxiliary power module controller 60 allows operation of the plurality of primary power switches 32. Line 435 represents a voltage level that does not include voltage ripple and is less than the OVSD threshold voltage 402. In this case, the auxiliary power module controller 60 allows operation of the plurality of primary power switches 32.

[0095] Figure 5 An embodiment of the auxiliary power system 20 is schematically illustrated for controlling reference Figure 1A process 500 is described for operation of an embodiment of a high voltage electrical power system 100 that includes an accessory power module 20 having a DC-DC electrical power converter 30. The method includes dynamically monitoring a ripple voltage on a high voltage bus multiplied by an AC gain of a high voltage input filter 510 by a peak detector circuit to determine a peak ripple voltage 520. The peak ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter is compared to a maximum threshold voltage of the plurality of primary power switches 530. When the ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter is greater than the maximum threshold voltage 530 (YES), the plurality of primary power switches are disabled 540. When the ripple voltage on the high voltage bus multiplied by the AC gain of the high voltage input filter is less than the maximum threshold voltage 530 (NO), the plurality of primary power switches are reactivated and monitoring continues 510.

[0096] Accordingly, methods, systems, and apparatuses are described for controlling operation of an accessory power module that includes a DC-DC electrical power converter. The accessory power module is controlled in a manner that prevents, avoids, or otherwise excludes exposing high voltage electronic power switches, such as power MOSFET switches, to dynamically varying electrical power levels that are greater than a threshold voltage level. The threshold voltage level is based on a maximum rated voltage of the electronic power switches. The electrical power levels that are greater than the threshold voltage level can be transient voltage levels caused by voltage ripple induced by another device electrically connected to the high voltage electrical power system, such as a power inverter.

[0097] The term "signal" means a physically discernible indication that conveys information and can be a suitable waveform (e.g., electrical, optical, magnetic, mechanical, or electromagnetic) capable of being propagated over a medium, such as DC, AC, sine wave, triangle wave, square wave, vibrations, etc.

[0098] The terms "calibration," "calibrated," and related terms refer to a result or process of associating a desired parameter with one or more perceived or observed parameters for a device or system. Calibration as described herein can be reduced to a table of storable parameters, a plurality of executable equations, or another suitable form that can be used as part of a measurement or control routine.

[0099] A parameter is defined as a measurable quantity that represents a physical characteristic of a device or other element that can be discerned using one or more sensors and / or physical models. A parameter can have a discrete value, such as "1" or "0," or can vary infinitely in value.

[0100] The detailed description and drawings are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While some of the best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for practicing the present teachings defined in the claims.

Claims

1. An auxiliary power system electrically coupled to a high-voltage input filter downstream of a high-voltage bus, the auxiliary power system comprising: An auxiliary power module includes multiple primary power switches, a transformer, and multiple secondary rectifiers; wherein the multiple primary power switches are electrically connected to the high-voltage input filter downstream of the high-voltage bus, and wherein the multiple secondary rectifiers are electrically connected to the low-voltage output filter downstream of the low-voltage bus. A peak detector coupled to the high-voltage input filter downstream of the high-voltage bus; and A controller that communicates with the peak detector and is operatively connected to the plurality of primary power switches; The controller includes an instruction set that can execute the following: The peak detector dynamically monitors the AC ripple voltage of the high-voltage bus, multiplying it by the AC gain of the high-voltage input filter to obtain the voltage after gain. Compare the voltage after gain with the maximum threshold voltage; When the voltage after gain exceeds the maximum threshold voltage, the plurality of primary power switches are disabled; and When the voltage after gain is less than the maximum threshold voltage, the plurality of primary power switches are reactivated.

2. The accessory power system of claim 1, wherein, The peak detector includes a circuit having a series forward bias diode disposed upstream of a resistor and a capacitor, the resistor and the capacitor being disposed in parallel between the diode and ground, and wherein the RC time constant of the resistor and the capacitor is determined based on the frequency and amplitude of the AC ripple voltage and the target recovery time.

3. The accessory power system of claim 2, wherein, The target recovery time is determined based on the DC component of the high-voltage bus combined with the frequency and amplitude of the AC ripple voltage and the capacity of the low-voltage battery, which is electrically connected to the low-voltage output filter downstream of the low-voltage bus.

4. The accessory power system of claim 2, wherein, The circuitry of the peak detector is implemented as a software routine.

5. The accessory power system of claim 2, wherein, The circuitry of the peak detector is implemented as a plurality of electrical components.

6. The auxiliary power system according to claim 1, wherein, The plurality of primary power switches include power MOSFET switches, and wherein the maximum threshold voltage is determined based on the maximum rated voltage of the power MOSFET switch.

7. The auxiliary power system according to claim 6, wherein, The maximum rated voltage of the power MOSFET switch includes the maximum drain-source voltage.

8. An electrical system comprising: DC power supply, which is electrically connected to the power inverter via a high-voltage electrical bus; An auxiliary power module is electrically coupled to a high-voltage input filter downstream of the high-voltage bus. as well as An overvoltage shutdown system includes a peak detector, a comparator, and a controller coupled to the high-voltage input filter downstream of the high-voltage bus. The auxiliary power module includes a DC-DC power converter with multiple primary power switches, transformers, and multiple secondary rectifiers. The plurality of primary power switches are electrically connected to the high-voltage input filter downstream of the high-voltage bus. The auxiliary power module is coupled to the low-voltage power bus. The controller communicates with the peak detector and is operatively connected to the plurality of primary power switches; The controller includes an instruction set that can execute the following: The voltage after gain is obtained by dynamically monitoring the AC ripple voltage on the high-voltage bus by the peak detector and multiplying it by the AC gain of the high-voltage input filter. The comparator compares the post-gain voltage with the maximum threshold voltage; and When the voltage after gain of the high-voltage bus is greater than the maximum threshold voltage, the plurality of primary power switches are disabled.

9. The electrical system according to claim 8, wherein, The peak detector includes a circuit having a series forward bias diode disposed upstream of a resistor and a capacitor, the resistor and the capacitor being disposed in parallel between the diode and ground, and wherein the RC time constant of the resistor and the capacitor is determined based on the frequency and amplitude of the AC ripple voltage and the target recovery time.

10. The electrical system according to claim 9, wherein, The target recovery time is determined based on the frequency and amplitude of the AC ripple voltage and the storage capacity of the low-voltage battery of the low-voltage power bus.

11. The electrical system according to claim 9, wherein, The peak detector is implemented as a software routine.

12. The electrical system according to claim 9, wherein, The peak detector is implemented as an electrical component circuit.

13. The electrical system according to claim 8, wherein, The output signal from the peak detector is the first input of the comparator, wherein the maximum threshold voltage is the second input of the comparator, and wherein the output of the comparator is operatively connected to the plurality of primary power switches of the auxiliary power module.

14. The electrical system according to claim 8, wherein, The plurality of primary power switches include power MOSFET switches, and wherein the maximum threshold voltage is determined based on the maximum rated voltage of the power MOSFET switch.

15. The electrical system according to claim 14, wherein, The maximum rated voltage of the power MOSFET switch includes the maximum drain-source voltage.

16. The electrical system according to claim 8, wherein, The instruction set can be executed to reactivate the plurality of primary power switches when the post-gain voltage on the high-voltage bus is less than the maximum threshold voltage.

17. A method for controlling an auxiliary power module, the auxiliary power module comprising a DC-DC power converter having a plurality of primary power switches, a transformer, and a plurality of secondary rectifiers, wherein, The plurality of primary power switches are electrically connected to a high-voltage input filter downstream of the high-voltage bus, and the method includes: The voltage after gain is obtained by dynamically monitoring the AC ripple voltage on the high-voltage bus by multiplying it by the AC gain of the high-voltage input filter using a peak detector circuit. Compare the post-gain voltage with the maximum threshold voltage of the plurality of primary power switches; and When the voltage after gain exceeds the maximum threshold voltage, the plurality of primary power switches are disabled.

18. The method of claim 17, further comprising reactivating the plurality of primary power switches when the voltage after gain is less than the maximum threshold voltage.

19. The method of claim 17, wherein, The plurality of primary power switches include power MOSFET switches, and wherein the maximum threshold voltage is determined based on the maximum rated voltage of the power MOSFET switch.

20. The method according to claim 19, wherein, The maximum rated voltage of the power MOSFET switch includes the maximum drain-source voltage.

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