System and method for testing capacitors in a circuit

Abstract

The invention relates to a system and a method for testing a capacitor in a circuit. In an example, a test circuit includes a test voltage source configured to output a test voltage to a capacitor; a discharge network configured to dissipate power from the capacitor; a voltage detection circuit configured to measure a voltage of the capacitor; a first switch configured to connect the capacitor to the main circuit; a second switch configured to connect the capacitor to a discharge network; a third switch configured to connect the capacitor to a test voltage source; and a fourth switch configured to connect the capacitor to the voltage detection circuit; and one or more controllers. The controller is configured to control operation of the switch to test the capacitor using the test voltage source, the discharge network, and the voltage detection circuit, and to determine whether the capacitor is connected according to the test.

Description

Technical Field

[0001] Various embodiments of the present disclosure generally relate to testing capacitors, and more specifically but not limited to systems and methods for testing high-voltage capacitors used in high-voltage circuits such as battery charging systems for electric vehicles. Background Art

[0002] Capacitors are widely used in high-voltage applications (such as battery charging systems) for different purposes (e.g., smoothing ripples in voltage). Circuits using capacitors can be exposed to environmental factors (such as heat, cold, humidity, and shock). Due to these environmental factors, capacitors may become detached from or malfunction in the circuit board, which may result in an open circuit in the system, thereby degrading the system's performance.

[0003] The present disclosure relates to overcoming one or more of these challenges. Summary of the Invention

[0004] In some embodiments, the techniques described herein relate to a system including: an alternating current (AC) to direct current (DC) converter (AC-DC converter) that receives power; a DC-DC converter (DC-DC converter) connected to the AC-DC converter to charge a battery based on the received power; a noise filter including a capacitor; a test circuit for testing the capacitor, the test circuit including: a test voltage source for outputting a test voltage to the capacitor; a discharge network configured to dissipate power from the capacitor; a voltage detection circuit configured to measure the voltage of the capacitor as a measured voltage; a first switch configured to connect the capacitor to a main circuit; a second switch configured to connect the capacitor to the discharge network; a third switch for connecting the capacitor to the test voltage source; a fourth switch for connecting the capacitor to the voltage detection circuit; and one or more controllers configured to (i) control the operation of the first switch, the second switch, the third switch, and the fourth switch to test the capacitor using the test voltage source, the discharge network, and the voltage detection circuit, and (ii) determine based on the test whether the capacitor is connected to the noise filter.

[0005] In some embodiments, the techniques described herein relate to a system further including an electric vehicle that includes a battery connected to the DC-DC converter.

[0006] In some embodiments, the techniques described herein relate to a system. The one or more controllers are further configured to: close the second switch to connect the capacitor to the discharge network; close the third switch to apply a test voltage to the capacitor; and close the fourth switch to connect the capacitor to the voltage detection circuit.

[0007] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: determine that a measured voltage is below a threshold; and in response to determining that the measured voltage is below the threshold, determine that the capacitor is disconnected from the noise filter.

[0008] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: determine that a measured voltage is above a threshold; and in response to determining that the measured voltage is above the threshold, determine that the capacitor is connected to the noise filter.

[0009] In some embodiments, the techniques described herein relate to a system. One or more controllers are configured to close a first switch to connect the capacitor to the noise filter.

[0010] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: open the first switch to disconnect the capacitor from the noise filter; and close a second switch to connect the capacitor to a discharge network.

[0011] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: open the second switch to disconnect the capacitor from the discharge network; and close a third switch to apply a test voltage source to the capacitor.

[0012] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: open the third switch to disconnect the test voltage source from the capacitor; and close a fourth switch to connect the capacitor to a voltage detection circuit.

[0013] In some embodiments, the techniques described herein relate to a method that includes performing operations using one or more controllers, the operations including: connecting the capacitor to a discharge network; after a first time period, disconnecting the capacitor from the discharge network and applying a test voltage to the capacitor; after a second time period, disconnecting the test voltage from the capacitor and connecting the capacitor to a voltage detection circuit; measuring a voltage at the capacitor at the voltage detection circuit as a measured voltage; comparing the measured voltage to a threshold voltage; and in response to the comparison, determining whether the capacitor is connected or disconnected.

[0014] In some embodiments, the techniques described herein relate to a method. The operations further include: when the measured voltage is below the threshold voltage, determining that the capacitor is disconnected; and when the measured voltage is above the threshold voltage, determining that the capacitor is connected.

[0015] In some embodiments, the techniques described herein relate to a method. The operations further include: disconnecting a test voltage; and after disconnecting the test voltage, delaying the connection of the capacitor to the voltage detection circuit for a third time period.

[0016] In some embodiments, the techniques described herein relate to a method. The operations further include: receiving an additional voltage measurement at the capacitor from the voltage detection circuit; and detecting a peak of the voltage at the capacitor based on the additional voltage measurement.

[0017] In some embodiments, the techniques described herein relate to a system that includes: a test circuit configured to test a capacitor, the test circuit including: a test voltage source configured to output a test voltage to the capacitor; a discharge network configured to dissipate power from the capacitor; a voltage detection circuit configured to measure the voltage of the capacitor as a measured voltage; a first switch configured to connect the capacitor to a main circuit; a second switch configured to connect the capacitor to the discharge network; a third switch configured to connect the capacitor to the test voltage source; and a fourth switch configured to connect the capacitor to the voltage detection circuit; and one or more controllers configured to (i) control the operation of the first switch, the second switch, the third switch, and the fourth switch to test the capacitor using the test voltage source, the discharge network, and the voltage detection circuit, and (ii) determine whether the capacitor is connected to the test circuit based on the measured voltage.

[0018] In some embodiments, the techniques described herein relate to a system. The one or more controllers are further configured to: control the operation of the second switch to close, thereby connecting the capacitor to the discharge network; control the operation of the third switch to close, thereby applying a test voltage to the capacitor; and control the operation of the fourth switch to close, thereby connecting the capacitor to the voltage detection circuit.

[0019] In some embodiments, the techniques described herein relate to a system. The one or more controllers are further configured to: determine that the measured voltage is below a threshold; and in response to determining that the measured voltage is below the threshold, determine that the capacitor is disconnected.

[0020] In some embodiments, the techniques described herein relate to a system. The one or more controllers are further configured to: determine that the measured voltage is above a threshold; and in response to determining that the measured voltage is above the threshold, determine that the capacitor is connected.

[0021] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to control the operation of a first switch to close, thereby connecting a capacitor to a main circuit.

[0022] In some embodiments, the techniques described herein relate to a system. One or more controllers are also configured to: control the operation of a first switch to open, thereby disconnecting the capacitor from the main circuit; control the operation of a second switch to close, thereby applying the capacitor to a discharge network; control the operation of the second switch to open, thereby disconnecting the capacitor from the discharge network; control the operation of a third switch to close, thereby applying a test voltage to the capacitor; control the operation of the third switch to open, thereby disconnecting the test voltage source from the capacitor; and control the operation of a fourth switch to close, thereby connecting the capacitor to a voltage detection circuit.

[0023] In some embodiments, the techniques described herein relate to a system, further comprising: a first resistor connected between the third switch and the test voltage source; a diode connected to the fourth switch; and a second resistor connected between the fourth switch and the voltage detection circuit.

[0024] The additional objectives and advantages of the disclosed embodiments will be partly set forth in the following description, and partly will be obvious from the description, or may be learned by practicing the disclosed embodiments. The objectives and advantages of the disclosed embodiments will be realized and attained by the elements and combinations particularly pointed out in the appended claims.

[0025] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory, and are not restrictive of the disclosed embodiments claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings incorporated in and constituting a part of this specification illustrate various exemplary embodiments and, together with the specification, serve to explain the principles of the disclosed embodiments.

[0027] Figure 1 An exemplary system infrastructure for a battery charger according to one or more embodiments is depicted.

[0028] Figure 2 An exemplary system infrastructure for a vehicle including a battery charger according to one or more embodiments is depicted.

[0029] Figure 3 An implementation of a computer system that can execute the techniques presented herein according to one or more embodiments is depicted.

[0030] Figure 4Depicts an exemplary electrical schematic of a single-phase battery charger having a large-capacitance capacitor and a high-voltage filtering capacitor according to one or more embodiments.

[0031] Figure 5 Depicts an exemplary electrical schematic of a noise filtering circuit according to one or more embodiments.

[0032] Figure 6A 、 Figure 6B 、 Figure 6C 、 Figure 6D and Figure 6E Depicts an exemplary electrical schematic of a capacitor test circuit in various configurations according to one or more embodiments.

[0033] Figure 7 Depicts an exemplary method for testing a capacitor according to one or more embodiments.

[0034] Figure 8 Depicts an exemplary graph of various signals in a test circuit with a connected capacitor according to one or more embodiments.

[0035] Figure 9 Depicts an exemplary graph of various signals in a test circuit with a disconnected capacitor according to one or more embodiments. Detailed Description

[0036] The foregoing general description and the following detailed description are merely exemplary and explanatory and are not restrictive of the claimed features. As used herein, the terms "comprising," "including," "having," "has," "containing," "contains," or other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. In this disclosure, unless otherwise stated, relative terms such as "about," "substantially," and "approximately" are used to indicate a possible variation of ±10% of the stated value. In this disclosure, unless otherwise stated, any numerical value may include a possible variation of ±10% of the stated value.

[0037] The terms used below may be interpreted in their broadest reasonable manner, even when used in conjunction with the detailed description of certain specific examples of this disclosure. Indeed, certain terms may even be emphasized below; however, any term intended to be interpreted in a restricted manner will be explicitly and specifically so defined in this detailed description section.

[0038] Various embodiments of the present disclosure generally relate to testing capacitors, and more specifically but not limited to systems and methods for testing high-voltage capacitors used in high-voltage circuits such as battery charging systems for electric vehicles.

[0039] Some test systems lack the ability to test whether a capacitor is open and / or lack the ability to test a capacitor after it has been integrated into a circuit.

[0040] One or more embodiments may be applied to capacitors installed in a circuit, such as a battery charger (“main circuit”). One or more embodiments may provide a test circuit that can temporarily disrupt the main circuit during testing and otherwise allow the main circuit to operate independently of the test circuit. The test circuit can determine whether the capacitor has become disconnected from the main circuit or otherwise malfunctioned.

[0041] For purposes of discussion, the following non-limiting example is introduced. A controller within a capacitor test system controls various switches such that a capacitor in the main circuit is temporarily disconnected from the main circuit to facilitate testing of the capacitor and reconnected to the main circuit when testing is complete. Various combinations of switches can connect the capacitor to a discharge network and disconnect the capacitor from the discharge network, and connect the capacitor to a test voltage source and disconnect the capacitor from the test voltage source. During testing, the controller disconnects the capacitor from the main circuit and discharges the capacitor via the discharge network. After discharging for a period of time, the controller connects the capacitor to a power source that applies a test voltage to the capacitor. After applying the test voltage for a period of time (e.g., a known period of time), the controller then connects the capacitor to a detection circuit. The detection circuit obtains measurements of the output voltage from the capacitor over time. As further discussed herein, based on these measurements, the controller can determine whether the capacitor is correctly connected to the main circuit and is operating correctly.

[0042] While the examples discussed herein describe testing capacitors in a battery charging circuit (as discussed with respect to Figures 1 to 4 discussed) or a noise reduction circuit (as discussed with respect to Figure 5 discussed), the present disclosure is not limited thereto. Instead, one or more embodiments may provide systems and methods for testing capacitors installed in any circuit.

[0043] Figure 1 An exemplary system infrastructure for a battery charger is depicted in accordance with one or more embodiments. As Figure 1As shown, the battery charger 100 may include or be electrically connected to a charging connector 110. The charging connector 110 may provide an electrical connection from an external power source to the battery charger 100 and may be, for example, a Type 1 or Type 2 connector. The charging connector 110 may transmit single-phase, two-phase, or three-phase power.

[0044] The battery charger 100 may include a power factor correction (PFC) converter 120, an HV DC-DC converter 130, and a controller 300 that receives signals from an input sensor 150. The power factor correction (PFC) converter 120 may be an AC-DC converter. The HV DC-DC converter 130 may be a DC-DC converter. The controller 300 may include one or more controllers. The battery charger 100 may include or be electrically connected to a battery 140. The battery charger 100 may be used as an on-vehicle charger in a motor vehicle to transfer power from an external power source to the battery 140 through the charging connector 110 in a grid-to-battery operation, or transfer power from the battery 140 in a vehicle-to-grid configuration (battery-to-grid operation). The battery charger 100 may be included in a system provided as an electric vehicle that includes a motor configured to rotate based on power received from the battery 140.

[0045] Figure 2 An exemplary system infrastructure for a vehicle including a battery charger is depicted according to one or more embodiments. The battery charger 100 may be a combined inverter and converter. As Figure 2 shown, the electric vehicle 185 may include a battery charger 100, a motor 190, and a battery 140. The battery charger 100 may include components that receive power from an external source and output power to charge the battery 140 of the electric vehicle 185. For example, the battery charger 100 may convert DC power from the battery 140 in the electric vehicle 185 into AC power to drive the motor 190 of the electric vehicle 185, but the embodiments are not limited thereto. For example, the battery charger 100 may include components for receiving power from an external source and outputting power to charge the battery 140 without the motor 190 being connected to the battery charger 100. The battery charger 100 may convert DC power from the battery 140 in the electric vehicle 185 into AC power to drive AC components of the electric vehicle 185 other than the motor 190. The battery charger 100 may be bidirectional and may convert DC power into AC power, or convert AC power into DC power, for example, during regenerative braking. The battery charger 100 may be a three-phase inverter, a single-phase inverter, or a multi-phase inverter.

[0046] Figure 3Depicts an embodiment of a controller 300 that can perform the techniques presented herein according to one or more embodiments. For example, the controller 300 can control the capacitor test circuit further discussed with respect to Figures 6A to 6E Additionally or alternatively, the controller 300 can be used to control the battery charging circuit with respect to Figure 1 , Figure 2 and Figure 4 discussed. In some cases, the controller 300 can be used as a detection circuit for the voltage of a capacitor under test. For example, in a low voltage test application, the capacitor under test can be connected to the input of the controller 300 during the discharge phase of the test, as further discussed with respect to Figures 5 to 7 .

[0047] Any suitable system infrastructure can be put in place to allow control of the battery charger. Figure 3 And the following discussion provides a brief general description of a suitable computing environment in which the present disclosure can be implemented. In one embodiment, any of the disclosed systems, methods, and / or graphical user interfaces can be executed or implemented by a computing system consistent or similar to that depicted in Figure 3 . Although not required, embodiments of the present disclosure are described in the context of computer-executable instructions, such as routines executed by a data processing device (e.g., a server computer, a wireless device, and / or a personal computer). Those skilled in the relevant art will understand that embodiments of the present disclosure can be practiced with other communication, data processing, or computer system configurations, including: Internet devices, handheld devices (including personal digital assistants (“PDAs”)), wearable computers, all manner of cellular or mobile phones (including Internet Protocol voice (“VoIP”) phones), dumb terminals, media players, gaming devices, virtual reality devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, set-top boxes, network PCs, minicomputers, mainframe computers, etc. Indeed, the terms “computer,” “server,” etc. are generally used interchangeably herein and refer to any of the above devices and systems and any data processor.

[0048] Embodiments of the present disclosure may be embodied in a special purpose computer and / or a data processor that is specially programmed, configured, and / or constructed to execute one or more computer-executable instructions explained in detail herein. Although embodiments of the present disclosure (such as certain functions) are described as being executed specifically on a single device, the present disclosure may also be practiced in a distributed environment where functions or modules are shared among different processing devices linked by a communication network (such as a local area network (“LAN”), a wide area network (“WAN”), and / or the Internet). Similarly, techniques presented herein as involving multiple devices may be implemented in a single device. In a distributed computing environment, program modules may be located in local and / or remote memory storage devices.

[0049] Embodiments of the present disclosure may be stored and / or distributed on a non-transitory computer-readable medium, including magnetic or optically readable computer discs, hard-wired or pre-programmed chips (such as EEPROM semiconductor chips), nanotechnology memories, biological memories, or other data storage media. Alternatively, computer-implemented instructions, data structures, screen displays, and other data under embodiments of the present disclosure may be distributed over the Internet and / or other networks (including wireless networks), over a propagation signal distributed over a propagation medium (such as electromagnetic waves, sound waves, etc.) for a period of time, and / or they may be provided on any analog or digital network (packet switching, circuit switching, or other schemes).

[0050] The controller 300 may include an instruction set that may be executed to cause the controller 300 to perform any one or more of the methods or computer-based functions disclosed herein. The controller 300 may operate as a stand-alone device or may be connected to other computer systems or peripheral devices, for example, using a network.

[0051] In a networked deployment, the controller 300 can operate with the capabilities of a server, or as a client in a server-client user network environment, or as a peer computer system in a peer-to-peer (or distributed) network environment. The controller 300 can also be implemented as or incorporated into a variety of devices, such as a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile device, handheld computer, laptop computer, desktop computer, communication device, wireless phone, landline phone, control system, camera, scanner, fax machine, printer, pager, personal trusted device, network appliance, network router, switch, or bridge, or any other machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. In a particular implementation, an electronic device providing voice, video, or data communication can be used to implement the controller 300. Additionally, although the controller 300 is shown as a single system, the term "system" should also be regarded as including any collection of systems or subsystems that, individually or jointly, execute one or more sets of instructions to perform one or more computer functions.

[0052] As Figure 3 shown, the controller 300 can include a processor 302, such as a central processing unit (CPU), a graphics processing unit (GPU), or both. The processor 302 can be a component in a variety of systems. For example, the processor 302 can be part of a standard computer. The processor 302 can be one or more general-purpose processors, digital signal processors, application specific integrated circuits, field programmable gate arrays, servers, networks, digital circuits, analog circuits, combinations thereof, or other devices now known or later developed for analyzing and processing data. The processor 302 can implement software programs, such as manually generated (i.e., programmed) code.

[0053] The controller 300 may include a memory 304 that can communicate via a bus 308. The memory 304 may be a main memory, a static memory, or a dynamic memory. The memory 304 may include, but is not limited to, computer-readable storage media, such as various types of volatile and non-volatile storage media, including but not limited to random access memory, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory, magnetic tapes or disks, optical media, etc. In one embodiment, the memory 304 includes a cache or random access memory for the processor 302. In an alternative implementation, the memory 304 is separate from the processor 302, such as a cache memory of the processor, a system memory, or other memories. The memory 304 may be an external storage device or a database for storing data. Examples include hard disk drives, compact discs ("CDs"), digital video discs ("DVDs"), memory cards, memory sticks, floppy disks, universal serial bus ("USB") memory devices, or any other device operable to store data. The memory 304 is operable to store instructions executable by the processor 302. The functions, actions, or tasks shown in the figures or described herein may be performed by the processor 302 executing instructions stored in the memory 304. The functions, actions, or tasks are independent of a particular type of instruction set, storage medium, processor, or processing strategy, and may be performed by software, hardware, integrated circuits, firmware, microcode, etc., operating alone or in combination. Similarly, the processing strategy may include multiprocessing, multitasking, parallel processing, etc.

[0054] As shown, the controller 300 may further include a display 310, such as a liquid crystal display (LCD), an organic light emitting diode (OLED), a flat panel display, a solid state display, a cathode ray tube (CRT), a projector, a printer, or any other currently known or later developed display device for outputting determined information. The display 310 may act as an interface for a user to see the functions of the processor 302, or specifically act as an interface to the software stored in the memory 304 or the drive unit 306.

[0055] Additionally or alternatively, the controller 300 may include an input device 312 configured to allow a user to interact with any component of the controller 300. The input device 312 may be a numeric keypad, a keyboard, or a cursor control device, such as a mouse or a joystick, a touch screen display, a remote control, or any other device operable to interact with the controller 300.

[0056] The controller 300 may also or alternatively include a drive unit 306 implemented as a disk or optical disk drive. The drive unit 306 may include a computer-readable medium 322, in which one or more sets of instructions 324, such as software, may be embedded. Additionally, the instructions 324 may embody one or more of the methods or logics described herein. The instructions 324 may reside, in whole or in part, within the memory 304 and / or within the processor 302 during execution by the controller 300. The memory 304 and the processor 302 may also include the computer-readable medium as described above.

[0057] In some systems, the computer-readable medium 322 includes the instructions 324, or receives and executes the instructions 324 in response to a propagated signal, such that a device connected to the network 370 can transmit voice, video, audio, images, or any other data via the network 370. Additionally, the instructions 324 may be sent or received via the communication port or interface 320 and / or using the bus 308 via the network 370. The communication port or interface 320 may be part of the processor 302, or may be a separate component. The communication port or interface 320 may be created in software, or may be a physical connection in hardware. The communication port or interface 320 may be configured to connect to the network 370, an external medium, the display 310, or any other component of the controller 300 or a combination thereof. The connection to the network 370 may be a physical connection, such as a wired Ethernet connection, or may be established wirelessly as described below. Similarly, additional connections to other components of the controller 300 may be physical connections or may be established wirelessly. The network 370 may alternatively be directly connected to the bus 308.

[0058] Although the computer-readable medium 322 is shown as a single medium, the term "computer-readable medium" may include a single medium or multiple media, such as a centralized or distributed database, and / or associated caches and servers storing one or more sets of instructions. The term "computer-readable medium" may also include any medium capable of storing, encoding, or carrying a set of instructions for execution by a processor or causing a computer system to execute any one or more of the methods or operations disclosed herein. The computer-readable medium 322 may be non-transitory and may be tangible.

[0059] The computer-readable medium 322 can include solid-state memory such as a memory card or other encapsulation that houses one or more non-volatile read-only memories. The computer-readable medium 322 can be random access memory or other volatile rewritable memory. Additionally or alternatively, the computer-readable medium 322 can include magneto-optical or optical media such as a disk or tape or other storage device to capture a carrier signal such as a signal transmitted through a transmission medium. Digital file attachments of e-mails or other self-contained information archives or sets of archives can be considered a distribution medium as a tangible storage medium. Accordingly, the present disclosure is considered to include any one or more of a computer-readable medium or a distribution medium in which data or instructions can be stored and other equivalents and successor media.

[0060] In alternative embodiments, dedicated hardware implementations (e.g., application specific integrated circuits, programmable logic arrays, and other hardware devices) can be constructed to implement one or more of the methods described herein. Applications of devices and systems that can include various implementations can broadly include a variety of electronic and computer systems. One or more implementations described herein can use two or more specific interconnected hardware modules or devices to perform functions, where relevant control and data signals can be transmitted between and through the modules or as part of an application specific integrated circuit. Accordingly, the present system encompasses software, firmware, and hardware implementations.

[0061] The controller 300 can be connected to a network 370. The network 370 can define one or more networks including wired or wireless networks. The wireless network can be a cellular telephone network, 802.11, 802.16, 802.20, or WiMAX network. Additionally, such networks can include a public network (such as the Internet), a private network (such as an intranet), or a combination thereof, and can utilize a variety of network protocols now available or later developed, including but not limited to TCP / IP-based network protocols. The network 370 can include a wide area network (WAN) such as the Internet, a local area network (LAN), a campus local area network, a metropolitan area network, a direct connection such as through a universal serial bus (USB) port, or any other network that can permit data communication. The network 370 can be configured to couple one computing device to another computing device to enable data communication between the devices. The network 370 can generally employ any form of machine-readable medium to transfer information from one device to another. The network 370 can include communication methods by which information can propagate between computing devices. The network 370 can be divided into subnets. The subnets can permit access to all other components connected thereto, or the subnets can restrict access between components. The network 370 can be considered a public or private network connection and can include, for example, a virtual private network or encryption or other security mechanisms employed over the public Internet.

[0062] According to various embodiments of the present disclosure, the methods described herein may be implemented by software programs executable by a computer system. Additionally, in an exemplary non-limiting implementation, the implementation may include distributed processing, component / object distributed processing, and parallel processing. Alternatively, virtual computer system processing may be configured to implement one or more of the methods or functions described herein.

[0063] Although this specification describes components and functions that may be implemented in particular implementations with reference to specific standards and protocols, the present disclosure is not limited to such standards and protocols. For example, standards for Internet and other packet-switching network transmissions (e.g., TCP / IP, UDP / IP, HTML, and HTTP) represent examples of the prior art. Such standards are periodically replaced by faster or more efficient equivalents that perform substantially the same functions. Accordingly, replacement standards and protocols having the same or similar functions as those disclosed herein are considered to be equivalents thereof.

[0064] It should be understood that in one embodiment, the steps of the methods discussed are performed by appropriate one or more processors of a processing (i.e., computer) system that executes instructions (computer-readable code) stored in a storage device. It will also be understood that the present disclosure is not limited to any particular implementation or programming technique, and the present disclosure may be implemented using any appropriate technique for implementing the functions described herein. The present disclosure is not limited to any particular programming language or operating system.

[0065] Figure 4 An exemplary electrical schematic of a single-phase battery charger having a bulk capacitor and a high-voltage filter capacitor is depicted according to one or more embodiments. As Figure 4 shown, the battery charger 100 may include a PFC converter 120 and an HV DC-DC converter 130. The PFC converter 120 may be connected to a line voltage 403, which may be, for example, a single-phase voltage. The HV DC-DC converter 130 may be connected to a battery 140. The HV DC-DC converter 130 is operable to isolate the PFC converter 120 from the battery 140. For example, the HV DC-DC converter 130 may be a CLLLC converter or any suitable DC-DC converter. Techniques described herein, for example, with respect to Figures 6A to 6E and Figure 7 may be used to test the bulk capacitor and / or the high-voltage filter capacitor.

[0066] The PFC converter 120 may include a PFC converter switch 420 and a bulk capacitor 423. The PFC converter switch 420 may be one or more switches, such as four NFET switches, for example, as Figure 4As shown. The PFC converter 120 may include other components, such as an inductor L and a current sensor CS. The techniques described herein may be used to test the bulk capacitor 423.

[0067] The HV DC-DC converter 130 may include a bridge driver switch 430, one or more transformers 433, a bridge rectifier switch 436, and an HV filter capacitor 439. The techniques described herein may be used to test the HV filter capacitor 439. The bridge driver switch 430 may be one or more switches, such as four NFET switches, for example, as Figure 4 shown. The bridge rectifier switch 436 may be one or more switches, such as four NFET switches, for example, as Figure 4 shown. The PFC converter 120 may include other components, such as a primary-side inductor LRP, a secondary-side inductor LRS, a primary-side capacitor CRP, a secondary-side capacitor CRS, and a current sensor CS.

[0068] The battery charger 100 may operate bidirectionally. A control strategy designed for multiple voltages may be utilized to implement a vehicle-to-grid (V2G) configuration. The PFC converter 120 may be configured to receive DC power from the battery 140 through the HV DC-DC converter 130, convert the DC power to AC power, and provide the AC power as an output to the line voltage 403. The controller 300 may be designed with an algorithm for controlling the operations of the PFC converter 120 and the HV DC-DC converter 130.

[0069] The bridge driver switch 430 may operate as a full-bridge driver or a half-bridge driver and transfer power as a square-wave signal from the PFC converter 120 to one or more transformers 433. One or more transformers 433 may be one or more high-frequency transformers and may be a single transformer having multiple coils or windings, multiple transformers having a single coil or winding, or any combination thereof. One or more transformers 433 may be connected to the bridge rectifier switch 436. The bridge rectifier switch 436 may convert the square-wave signal to DC power.

[0070] The controller 300 may be designed with and / or configured to execute an algorithm for controlling the PFC converter switch 420, the bridge driver switch 430, and the bridge rectifier switch 436.

[0071] Figure 5 Depicts an exemplary electrical schematic of a noise filter circuit 500 according to one or more embodiments. In the example depicted in the noise filter circuit 500, two capacitors are used to filter noise on the positive voltage rail and / or the negative voltage rail.

[0072] As shown, noise filter circuit 500 includes a positive voltage rail 502, a negative voltage rail 504, a first capacitor 506, a second capacitor 508, and ground 510. As shown, the first capacitor 506 is connected to the positive voltage rail 502, the second capacitor 508 is connected to the negative voltage rail 504, and both the first capacitor 506 and the second capacitor 508 are connected to ground 510. In some embodiments, some components of the noise filter circuit 500 may be omitted and / or other components may be added to the noise filter circuit 500.

[0073] Noise may be introduced into the system and be carried on one or more of the positive voltage rail 502 or the negative voltage rail 504. In the depicted example, the first capacitor 506 and the second capacitor 508 may reduce the noise on the positive voltage rail 502 and / or the negative voltage rail 504. For example, the first capacitor 506 and the second capacitor 508 may filter high-frequency noise (which may have been coupled with the high voltage on the positive voltage rail 502), thereby reducing EMI / RFI noise and associated side effects.

[0074] In some cases, the first capacitor 506 and the second capacitor 508 may be safety-certified capacitors. Such capacitors are useful in circuits where high voltages are used, such as in the case of a battery charging circuit. The techniques disclosed herein may be used to test the first capacitor 506 and the second capacitor 508, for example, by using Figures 6A to 6E the circuit depicted in. In some cases, capacitors such as the first capacitor 506 and the second capacitor 508 may become disconnected from the main circuit (e.g., one or more of the positive voltage rail 502, the negative voltage rail 504, or ground 510) due to shock or vibration.

[0075] Capacitor testing may occur during or after a purposeful shock or vibration test. For example, shock and vibration tests may be performed using a system that includes a circuit such as the noise filter circuit 500, as such a system can be designed to have a high tolerance to the effects of shock and vibration.

[0076] In an example, testing may be performed such that the vibration test is performed at 5G force (force per unit mass) every 10 minutes, where the force is increased until the vibration reaches 25G force. By using the techniques described herein, a system may be designed such that integrated capacitor testing capabilities. In this way, during or after such testing, it can be determined whether the capacitor is still connected and functioning without the need to remove a protective cover.

[0077] Figures 6A to 6EDepicts an exemplary electrical schematic of a capacitor test circuit 600 in various configurations according to one or more embodiments. In the depicted example, a test is performed on capacitor 606 to determine whether capacitor 606 has been disconnected from the main circuit. Reasons for disconnection include physical separation of capacitor 606 from the circuit and capacitor 606 otherwise not functioning.

[0078] More specifically, capacitor test circuit 600 includes a positive voltage rail 602, capacitor 606, ground 610, first switch (S1) 611, second switch (S2) 612, third switch (S3) 613, fourth switch (S4) 614, first resistor 620, second resistor 622, diode 624, power supply 626, discharge network 630, and detection circuit 632.

[0079] Capacitor 606 may correspond to the first capacitor 506 of noise filter circuit 500. However, capacitor 606 can be any capacitor. For example, capacitor 606 may correspond to the second capacitor 508 of noise filter circuit 500, or may correspond to another capacitor in another circuit.

[0080] As further explained below, capacitor test circuit 600 can operate in various modes or configurations, including for example an open mode, a normal mode, and a test mode. Figure 6A The open mode depicted in shows that the main circuit (e.g., the positive voltage rail 602 or the connecting components of noise filter circuit 500) and capacitor test circuit 600 are disconnected from capacitor 606. Figure 6B The normal mode depicted in shows that the main circuit is connected to capacitor 606 and capacitor test circuit 600 is disconnected from capacitor 606. For example, in the normal mode, noise from positive voltage rail 602 can be discharged to ground 610 through capacitor 606. Figures 6C to 6E Different test phases of the test mode are depicted in.

[0081] One or more embodiments can operate the test mode by opening or closing the first switch 611, second switch 612, third switch 613, and fourth switch 614 in various combinations. Different configurations of the first switch 611, second switch 612, third switch 613, and fourth switch 614 can appropriately connect or disconnect the positive voltage rail 602, power supply 626, discharge network 630, and / or detection circuit 632 from capacitor 606. Regarding Figure 7 Further discuss examples of methods for testing capacitor 606.

[0082] The first switch 611, the second switch 612, the third switch 613, and the fourth switch 614 can be any type of switch. In the example, since high voltage and high current are being processed, the first switch 611 and the second switch 612 can be relays. The third switch 613 and the fourth switch 614 can be used as corresponding isolation switches for the power supply 626 and the detection circuit 632. The third switch 613 and the fourth switch 614 can be MOSFET switches. The controller 300 can control the operations of the first switch 611, the second switch 612, the third switch 613, and the fourth switch 614. The controller 300 can perform tests during the startup of the main circuit (e.g., the noise filter circuit 500 as shown Figure 5 as) deployed within a battery charging system (e.g., the battery charger 100) and / or as needed.

[0083] The first switch 611 can be closed to connect the capacitor 606 to the positive voltage rail 602 and can be opened to disconnect the capacitor 606 from the positive voltage rail 602. In some cases, after the first switch 611 is closed, the controller 300 can impose a delay on closing any other switch to avoid false overlap. In some applications, such as battery charging, the positive voltage rail 602 can represent a high voltage, such as 240 volts or 400 volts.

[0084] The second switch 612 can be closed to connect the capacitor 606 to the discharge network 630 and can be opened to disconnect the capacitor 606 from the discharge network 630. When connected to the capacitor 606, the discharge network 630 can dissipate the power from the capacitor 606, causing the capacitor 606 to partially or fully discharge. In some cases, the controller 300 can impose a minimum connection time to ensure the full discharge of the capacitor 606. Non-limiting examples of the discharge network 630 can include a passive network (such as a passive network including one or more resistors) and an active network (such as an active network including MOSFETs). In some cases, an existing discharge network in the main circuit, for example, can be used instead of the discharge network 630.

[0085] The third switch 613 can be closed to connect the capacitor 606 to the power supply 626 and can be opened to disconnect the capacitor 606 from the power supply 626. As shown, the power supply 626 can be a 5-volt power supply. However, the power supply 626 can be any suitable power supply, such as a 10-volt or 20-volt power supply. The first resistor 620 can be connected between the power supply 626 and the third switch 613 to pull up the voltage from the power supply 626. The resistance value of the first resistor 620 can be adjusted to manipulate the RC curve associated with charging the capacitor 606. For example, the value of the first resistor 620 can be manipulated to ensure the rapid charging of the capacitor 606. The resistance value of the first resistor 620 can depend on the capacitance value of the capacitor 606.

[0086] The fourth switch 614 can be closed to connect the capacitor 606 to the detection circuit 632 and can be opened to disconnect the capacitor 606 from the detection circuit 632. The detection circuit 632 can detect the voltage provided from the capacitor 606. The detection circuit 632 can obtain multiple measurements or samples over a period of time.

[0087] The detection circuit 632 can be implemented by various devices. For example, the detection circuit 632 can include a comparator. The detection circuit 632 can include a controller, such as the controller 300. In a low voltage application, for example, a 5 volt output from the power supply 626, the controller 300 can include an input configured to perform the detection. For example, the capacitor 606 can directly provide a signal to a port of the controller (e.g., the controller 300), and the controller can measure the signal. In a higher voltage application, additional buffer circuits can be used.

[0088] The diode 624 can ensure that current flows from the capacitor 606 to the detection circuit 632 in only one direction. The diode 624 can implement peak detection such that the detection circuit 632 can detect a peak voltage, for example, caused by the voltage output from the capacitor 606, which can follow the discharge curve.

[0089] The second resistor 622 can be connected between the diode 624 and the detection circuit 632. The resistance value of the second resistor 622 can be adjusted to modify the threshold of the peak detection. In an example, given a 5 volt output from the power supply 626, the resistance value of the second resistor 622 can be adjusted such that the detected peak is approximately 4.5 volts. The controller 300 can adjust the resistance value of the second resistor 622 to affect the discharge rate of the capacitor 606. In some cases, the resistance value of the second resistor 622 can be adjusted such that the discharge rate of the capacitor 606 is a slow discharge. The detection circuit 632 can include one or more capacitors (not shown) configured to temporarily hold the charge from the capacitor 606. The detection circuit 632 can use the temporarily held charge in the one or more capacitors to perform the measurement of the capacitor 606.

[0090] Figure 6A The capacitor test circuit 600 is depicted in an open mode or configuration. As Figure 6A shown, the first switch 611, the second switch 612, the third switch 613, and the fourth switch 614 are all open. In this configuration, the capacitor 606 is neither connected to the main circuit (e.g., Figure 5 the noise filter circuit 500 depicted in

[0091] Figure 6B depicts a capacitor test circuit 600 in a normal mode or configuration. In the normal configuration, the capacitor 606 is connected to the positive voltage rail 602 for normal operation, such as battery charging. As Figure 6B shown, during normal mode operation, the first switch 611 is closed, and the second switch 612, the third switch 613, and the fourth switch 614 are open. In the normal configuration, the capacitor 606 is connected to the positive voltage rail 602 and is disconnected from the capacitor test circuit 600 (e.g., the power supply 626, the discharge network 630, and the detection circuit 632). As Figure 5 depicted, when the first capacitor 506 is connected to the positive voltage rail 502 (and thus, for example, connected to the noise filter circuit 500), the first capacitor 506 (in combination with the second capacitor 508) can reduce noise in the system.

[0092] Figure 6C depicts the capacitor test circuit 600 in the discharge phase or configuration of the capacitor test. In the discharge phase, the capacitor test circuit 600 can discharge the capacitor 606 using the discharge network 630. When transitioning from the normal configuration to the discharge phase, the controller 300 can control the operation of the first switch 611 from closed to open, thereby disconnecting the positive voltage rail 602. In the discharge phase, the third switch 613 and the fourth switch 614 can remain open. In the discharge phase, the controller 300 can control the operation of the second switch 612 to close, thereby connecting the discharge network 630 to the capacitor 606. The capacitor test circuit 600 can hold for a first time period (e.g., 5 milliseconds) in the discharge phase to complete the discharge of the capacitor 606. Non-limiting examples of the first time period include 5 milliseconds, 1 to 5 seconds, and 40 to 60 seconds. For example, in the case where the discharge network 630 is a passive discharge network, the first time period can be 40 seconds to 60 seconds. In contrast, when the discharge network 630 is an active discharge network, the first time period can be 1 to 5 seconds. Other examples are possible.

[0093] Figure 6DDepicts a capacitor test circuit 600 during the charging phase or configuration of a capacitor test. During the charging phase, the controller 300 can control the operation of the second switch 612 to open and control the operation of the third switch 613 to close, such that the power supply 626 is connected to the capacitor 606. During the charging phase, the controller 300 can control the operation of the first switch 611 and the fourth switch 614 to remain open. During the charging phase, the controller 300 can control the operation of the third switch 613 to close for a second time period, such as 5 milliseconds, to charge the capacitor 606 to a threshold voltage level. For example, the capacitor 606 can be charged to 4.5 or 5 volts. In this case, to reduce the test time, a charging voltage of approximately 5 volts can be used. In this case, a resulting charging time of 5 milliseconds and a resulting detection time of 5 milliseconds can be produced, where the total test time is approximately 20 milliseconds. However, the present disclosure is not limited thereto. For example, in some cases, if a higher charging voltage is desired, the third switch 613 is opened for a longer amount of time.

[0094] Figure 6E Depicts a capacitor test circuit 600 during the detection phase or configuration of a capacitor test. During the detection phase, the controller 300 can control the operation of the third switch 613 to open, such that the power supply 626 is disconnected from the capacitor 606, and control the operation of the fourth switch 614 to close, such that the detection circuit 632 is connected to the capacitor 606. The controller 300 can control the operation of the third switch 613 to open and perform a delay after opening the third switch 613 and before closing the fourth switch 614. During the detection phase, the controller 300 can control the operation of the first switch 611 and the second switch 612 to remain open. In some examples, the detection phase lasts for a predetermined amount of time (e.g., 5 ms).

[0095] During the detection phase, the detection circuit 632 measures the output voltage from the capacitor 606 one or more times. Based on the detected voltage, the controller 300 can determine whether the capacitor 606 is connected (i.e., connected to the first switch 611 and ground 610). For example, when the capacitor 606 is connected, the detection circuit 632 can determine that the charging voltage of the capacitor 606 is similar to or lower than the voltage of the power supply 626. For example, when the power supply 626 is 5 volts and the capacitor 606 is connected, the measured voltage will be approximately 5 volts. In contrast, when the capacitor 606 is disconnected or otherwise fails, the measured voltage will be approximately 0 volts because the capacitor 606 was not charged during the charging phase.

[0096] After the detection phase, the controller 300 may control the capacitor test circuit 600 to be configured in the normal phase. In this way, the controller 300 may control the operation of the first switch 611 to close, and control the operations of the second switch 612, the third switch 613, and the fourth switch 614 to open. The controller 300 may control the operations of the second switch 612, the third switch 613, and the fourth switch 614 to open, and after a delay, control the operation of the first switch 611 to close, because the first switch 611 may introduce a higher voltage (e.g., a power supply 626 greater than 5 volts) into the circuit.

[0097] Figure 7 An exemplary method 700 for testing a capacitor in accordance with one or more embodiments is depicted. For illustrative purposes, method 700 is discussed with respect to the capacitor test circuit 600 controlled by the controller 300. However, method 700 may be applied to other capacitor test circuits and / or use different controllers. Although method 700 depicts various operations, not all of the listed operations may be performed and / or some operations may be appropriately repeated.

[0098] At block 705, method 700 may include: connecting a capacitor (e.g., capacitor 606) to a discharge network (e.g., discharge network 630). At block 705, the controller 300 may configure the capacitor test circuit 600 to be in the discharge phase as Figure 6C shown. For example, the controller 300 may connect the discharge network 630 to the capacitor 606 by controlling the first switch 611 to open, thereby disconnecting the connection to the positive voltage rail 602, controlling the third switch 613 and the fourth switch 614 to open, and controlling the second switch 612 to close, thereby connecting the discharge network 630 to the capacitor 606.

[0099] At block 710, method 700 may include: after a first time period after the discharge phase, disconnecting the capacitor (e.g., capacitor 606) from the discharge network (e.g., discharge network 630), and applying a test voltage to the capacitor. The first time period may be set such that the capacitor has sufficient time to discharge to approximately 0 volts. Then, the controller 300 may configure the capacitor test circuit 600 in the charging phase, as Figure 6D shown. In the charging phase, the controller 300 may control the second switch 612 to open, such that the discharge network 630 is disconnected from the capacitor 606, and control the third switch 613 to close, such that the power supply 626 is connected to the capacitor 606. In the charging phase, the controller 300 may control the first switch 611 and the fourth switch 614 to remain open.

[0100] At block 715, method 700 includes: after a second time period following the charging phase, disconnecting the test voltage from the capacitor (e.g., capacitor 606) and connecting the capacitor to a voltage detection circuit (e.g., detection circuit 632). The second time period may be set such that the capacitor has sufficient time to charge to the test voltage (e.g., approximately 5 volts). Then, controller 300 may configure capacitor test circuit 600 during the detection phase as shown in Figure 6E . After a second time period that may be different from the first time period discussed with respect to block 710, controller 300 may control third switch 613 to open, disconnecting power supply 626 from capacitor 606, and control fourth switch 614 such that detection circuit 632 is connected to capacitor 606. During the detection phase, controller 300 may control first switch 611 and fourth switch 614 to open.

[0101] In some cases, at block 715, method 700 may include: after the second time period has elapsed, waiting for a third time period before proceeding to block 720 such that power supply 626 is not erroneously maintained in a connected state for a time that overlaps with the operation performed at block 720. Thus, controller 300 may delay closing of fourth switch 614 after third switch 613 is opened, as discussed with respect to block 720.

[0102] At block 720, method 700 includes: measuring an output voltage from the capacitor (e.g., capacitor 606) by a voltage detection circuit (e.g., detection circuit 632). Method 700 may include: obtaining one or more voltage measurements or samples of the voltage output from the capacitor (as shown via fourth switch 614 and / or first resistor 620). Method 700 may include: converting the measurement via an analog-to-digital converter (not shown) for processing by controller 300. Figure 6E .

[0103] In some cases, at block 720, method 700 may include: connecting discharge network 630 to capacitor 606 by closing second switch 612 while connected to detection circuit 632. However, method 700 may include: discharging capacitor 606 via detection circuit 632 (i.e., opening second switch 612) without discharge network 630.

[0104] At block 725, method 700 may include: comparing the voltage measurement with a threshold voltage by controller 300. Different threshold voltages may be used. For example, when power supply 626 outputs 5 volts, the threshold voltage may be 4.8 volts. For example, the threshold voltage may be 75% of the test voltage emitted by power supply 626.

[0105] At block 730, method 700 may include: in response to the comparison, determining whether a capacitor (e.g., capacitor 606) is connected or disconnected from a main circuit (e.g., noise filter circuit 500). When the voltage measurement is less than the threshold voltage, controller 300 may determine that the capacitor is disconnected from the main circuit. Conversely, when one or more voltage measurements are above the threshold voltage, controller 300 may determine that the capacitor is connected to the main circuit. In some cases, controller 300 may obtain multiple voltage measurements. For example, controller 300 may receive a set of voltage measurements of the output voltage of the capacitor over a period of time. Based on the set of voltage measurements, controller 300 may determine whether the capacitor is connected to the main circuit. For example, when controller 300 detects a capacitor discharge curve measured by a decreasing output voltage over time, then controller 300 may determine the capacitor to be connected to the main circuit. Regarding Figure 8 such an example is depicted.

[0106] Figure 8 Exemplary graph 800 of various signals in a test circuit with a connected capacitor according to one or more embodiments is depicted. Figure 8 It includes graphs 810, 820, 830, and 840. Refer to Figures 6A to 6E for discussion Figure 8 . Graph 810 represents a signal indicating whether the third switch 613 is open or closed over time 802. A high signal (e.g., 5 volts) indicates that the third switch 613 is closed, and a low signal (e.g., 0 volts) indicates that the third switch 613 is open. As Figure 8 shown, the signal represented by graph 810 shows that the third switch 613 transitions from closed to open at approximately 5 ms. Graph 820 represents the signal measured by the detection circuit 632 over time 802. As Figure 8 shown, the signal represented by graph 820 shows a capacitor discharge curve at approximately 5 ms.

[0107] Graph 830 represents a signal indicating whether the fourth switch 614 is open or closed over time 802. A high signal (e.g., 5 volts) indicates that the fourth switch 614 is closed, and a low signal (e.g., 0 volts) indicates that the fourth switch 614 is open. As Figure 8 shown, the signal represented by graph 830 shows that the fourth switch 614 transitions from open to closed at approximately 5 ms and from closed to open at approximately 10 ms. Graph 840 represents the signal presented to the input of the detection circuit 632. A high signal (e.g., 5 volts) may indicate that the capacitor 606 is connected, and a low signal (e.g., 0 volts) may indicate that the capacitor 606 is disconnected. As Figure 8 shown, the signal represented by graph 840 indicates that the capacitor 606 is connected at approximately 5 ms.

[0108] As shown in graphs 810, 820, 830, and 840, from approximately 0 ms to approximately 5 ms, the third switch 613 is closed. Thus, the capacitor test circuit 600 operates in a charging phase, as depicted in Figure 6D and the capacitor 606 is being charged. At approximately 5 ms, the third switch 613 opens, as shown by transition 812, and the fourth switch 614 closes, as shown by transition 832. These transitions configure the capacitor test circuit 600 in a discharging phase, as shown in Figure 6E .

[0109] From approximately 5 ms to approximately 10 ms, the capacitor 606 is depicted as discharging in graph 822. One or more voltage measurements can be obtained at this time to determine the initial high voltage (peak) at approximately 5 ms during discharge and / or the transition from high voltage to low voltage. The signal depicted in graph 840 rises at transition 842, indicating the presence of a charged capacitor and thus a connected capacitor. At approximately 10 ms, the fourth switch 614 opens, as shown by transition 834. At this point, the test is complete (and can be repeated as needed).

[0110] Figure 9 Exemplary graph 900 depicts various signals in a test circuit in the case of a disconnected capacitor according to one or more embodiments. Figure 9 Including graphs 910, 920, 930, and 940. Refer to Figures 6A to 6E for discussion. Figure 9 Graph 910 represents a signal indicating whether the third switch 613 is open or closed over time 902. As Figure 8 described, a high signal indicates that the third switch 613 is closed, and a low signal indicates that the third switch 613 is open. As Figure 9 shown, the signal represented by graph 910 shows that the third switch 613 transitions from closed to open at approximately 5 ms. Graph 920 represents a signal measured by the detection circuit 632 over time 902. As Figure 9 depicted, the signal represented by graph 920 shows a transition 922 from high to low (e.g., from approximately 5 volts to approximately 0 volts) at approximately 5 ms.

[0111] Graph 930 represents a signal indicating whether the fourth switch 614 is open or closed over time 902. As Figure 8 described, a high signal indicates that the fourth switch 614 is closed, and a low signal indicates that the fourth switch 614 is open. As Figure 9As shown, the signal represented by graph 930 shows that the fourth switch 614 transitions from open to closed at approximately 5 ms and from closed to open at approximately 10 ms. Graph 940 represents the signal presented to the detection circuit 632 (e.g., from capacitor 606) over time 902. As described for Figure 8 a high signal (e.g., 5 volts) can indicate that capacitor 606 is connected, and a low signal (e.g., 0 volts) can indicate that capacitor 606 is disconnected. As Figure 9 shown, the signal represented by graph 940 indicates that capacitor 606 remains disconnected.

[0112] As shown in graphs 910, 920, 930, and 940, from approximately 0 ms to approximately 5 ms, the third switch 613 is closed. Thus, the capacitor test circuit 600 operates in a charging phase, as depicted in Figure 6D and capacitor 606 should be charged from power supply 626.

[0113] At approximately 5 ms, the third switch 613 opens, as shown by transition 912, and the fourth switch 614 closes, as shown by transition 932. In some cases, the third switch 613 opens after an additional delay to allow the third switch 613 to fully close before the fourth switch 614 is turned on. These transitions configure the capacitor test circuit 600 in a discharging phase, as Figure 6E shown. However, compared to Figure 8 the measured output of capacitor 606 from graph 920 shows a sharp transition from a high voltage to a low voltage at transition 922. This sharp transition indicates that the charging voltage (e.g., applied from approximately 0 ms to approximately 5 ms) has been removed.

[0114] Relative to Figure 8 , graph 920 does not include a slow discharge because capacitor 606 is not connected and / or not operating properly. Thus, graph 940 represents a low signal both before and after 5 ms. At approximately 10 ms, the fourth switch 614 opens, as shown by transition 934.

[0115] One or more embodiments can be applied to capacitors installed in a circuit, such as a battery charger (“main circuit”). One or more embodiments can provide a test circuit that can temporarily disrupt the main circuit during testing and can otherwise allow the main circuit to operate independently of the test circuit. One or more embodiments can determine whether a capacitor has become disconnected from the main circuit or otherwise malfunctioned.

[0116] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

Claims

1. A system, the system comprising: an AC-DC converter configured to receive power; a DC-DC converter connected to the AC-DC converter to charge a battery based on the received power; a noise filter including a capacitor; a test circuit configured to test the capacitor, the test circuit including: a test voltage source configured to output a test voltage to the capacitor; a discharge network configured to dissipate power from the capacitor; a voltage detection circuit configured to measure the voltage of the capacitor as a measurement voltage; a first switch configured to connect the capacitor to a main circuit; a second switch configured to connect the capacitor to the discharge network; a third switch configured to connect the capacitor to the test voltage source; and a fourth switch configured to connect the capacitor to the voltage detection circuit; and one or more controllers configured to: (i) control the operation of the first switch, the second switch, the third switch, and the fourth switch to test the capacitor using the test voltage source, the discharge network, and the voltage detection circuit, and (ii) determine whether the capacitor is connected to the noise filter based on the test.

2. The system according to claim 1, the system further comprising an electric vehicle including the battery connected to the DC-DC converter.

3. The system according to claim 1, wherein The one or more controllers are further configured to: close the second switch to connect the capacitor to the discharge network; close the third switch to apply the test voltage to the capacitor; and close the fourth switch to connect the capacitor to the voltage detection circuit.

4. The system according to claim 1, wherein The one or more controllers are further configured to: determine that the measurement voltage is lower than a threshold; and in response to determining that the measurement voltage is lower than the threshold, determine that the capacitor is disconnected from the noise filter.

5. The system according to claim 1, wherein, The one or more controllers are further configured to: determine that the measurement voltage is higher than the threshold; and in response to determining that the measurement voltage is higher than the threshold, determine that the capacitor is connected to the noise filter.

6. The system according to claim 1, wherein The one or more controllers are configured to close the first switch to connect the capacitor to the noise filter.

7. The system according to claim 1, wherein, The one or more controllers are further configured to: open the first switch to disconnect the capacitor from the noise filter; and close the second switch to connect the capacitor to the discharge network.

8. The system according to claim 1, wherein The one or more controllers are further configured to: open the second switch to disconnect the capacitor from the discharge network; and close the third switch to apply the test voltage source to the capacitor.

9. The system according to claim 1, wherein, The one or more controllers are further configured to: Open the third switch to disconnect the test voltage source from the capacitor; And Close the fourth switch to connect the capacitor to the voltage detection circuit.

10. A method including performing operations using one or more controllers, the operations including: Connect the capacitor to a discharge network; After a first time period, disconnect the capacitor from the discharge network and apply a test voltage to the capacitor; After a second time period, disconnect the test voltage from the capacitor and connect the capacitor to a voltage detection circuit; Measure the voltage at the capacitor as a measured voltage at the voltage detection circuit; Compare the measured voltage with a threshold voltage; And In response to the comparison, determine whether the capacitor is connected or disconnected.

11. The method according to claim 10, wherein, The operations further include: When the measured voltage is lower than the threshold voltage, determine that the capacitor is disconnected; and When the measured voltage is higher than the threshold voltage, determine that the capacitor is connected.

12. The method according to claim 10, wherein, The operations further include: Disconnect the test voltage; and After disconnecting the test voltage, delay the connection of the capacitor to the voltage detection circuit for a third time period.

13. The method according to claim 10, wherein, The operations further include: Receive a plurality of additional voltage measurements at the capacitor from the voltage detection circuit; and Based on the plurality of additional voltage measurements, detect a peak of the voltage at the capacitor.

14. A system, the system including: A test circuit configured to test a capacitor, the test circuit including: A test voltage source configured to output a test voltage to the capacitor; A discharge network configured to dissipate power from the capacitor; A voltage detection circuit configured to measure the voltage of the capacitor as a measured voltage; A first switch configured to connect the capacitor to a main circuit; A second switch configured to connect the capacitor to the discharge network; A third switch configured to connect the capacitor to the test voltage source; and A fourth switch configured to connect the capacitor to the voltage detection circuit; and One or more controllers configured to: (i) control the operation of the first switch, the second switch, the third switch, and the fourth switch to test the capacitor using the test voltage source, the discharge network, and the voltage detection circuit, and (ii) determine whether the capacitor is connected to the test circuit based on the measured voltage.

15. The system according to claim 14, wherein, The one or more controllers are further configured to: Control the operation of the second switch to close to connect the capacitor to the discharge network; Control the operation of the third switch to close to apply the test voltage to the capacitor; And Control the operation of the fourth switch to close to connect the capacitor to the voltage detection circuit.

16. The system according to claim 14, wherein, The one or more controllers are further configured to: Determine that the measured voltage is below a threshold; and In response to determining that the measured voltage is below the threshold, determine that the capacitor is disconnected.

17. The system according to claim 14, wherein The one or more controllers are further configured to: Determine that the measured voltage is above a threshold; and In response to determining that the measured voltage is above the threshold, determine that the capacitor is connected.

18. The system according to claim 14, wherein The one or more controllers are further configured to control the operation of the first switch to close, thereby connecting the capacitor to the main circuit.

19. The system according to claim 14, wherein, The one or more controllers are further configured to: Control the operation of the first switch to open, thereby disconnecting the capacitor from the main circuit; Control the operation of the second switch to close, thereby applying the capacitor to the discharge network; Control the operation of the second switch to open, thereby disconnecting the capacitor from the discharge network; Control the operation of the third switch to close, thereby applying the test voltage source to the capacitor; Control the operation of the third switch to open, thereby disconnecting the test voltage source from the capacitor; And Control the operation of the fourth switch to close, thereby connecting the capacitor to the voltage detection circuit.

20. The system according to claim 14, the system further comprising: A first resistor, the first resistor being connected between the third switch and the test voltage source; A diode, the diode being connected to the fourth switch; And A second resistor, the second resistor being connected between the fourth switch and the voltage detection circuit.

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