Detection of brush arcing in power systems

Abstract

Arrangement with a detection circuit, wherein the detection circuit is configured to: detect a brush arc in a power system based on an electrical signal from the power system and by measuring at least one operating information that can be inferred from at least one of a load current, a rotational speed, a duty cycle, a state of a state machine, a pole pair number or a pin input information; and to set a bit in response to the detection of the brush arc.

Description

[0001] This disclosure concerns power systems with brushes, such as AC generators, electric generators and electric motors.

[0002] An alternating current (AC) generator is a machine that converts mechanical energy into an alternating current ("AC") electrical signal. The AC generator can obtain this mechanical energy in the form of a rotating shaft known as the rotor. The rotor can generate a magnetic field that causes current to flow in a part of the AC generator known as the stator. There are two main ways for a rotor to generate a magnetic field. First, the rotor can have a permanent magnet, which generates a magnetic field that rotates with the rotor. AC generators that use a permanent magnet may be known as magnetos. Second, the rotor can generate a magnetic field in which an electric current flows through windings inside the rotor.

[0003] An AC generator may contain a brush that supplies an excitation current to the rotor, causing an electric current to flow through the windings inside the rotor. The brush may have a brush holder that presses the brush against the rotor. When the brush makes contact with the rotor, it can conduct an electric current. If there is a gap between the brush and the rotor, brush arcing can occur when the potential difference between the brush and the rotor creates an electric arc across the gap.

[0004] Similar configurations can exist in other power systems, such as electric motors and electric generators. An electric generator can operate on similar principles to an AC generator, converting mechanical energy into electrical energy. An electric motor can convert electrical energy into mechanical energy. Generators and electric motors can have rotating shafts and brushes that conduct an electric current to the rotating shafts.

[0005] This disclosure describes techniques for a detection circuit configured to detect brush arcing in a power system based on an electrical signal from the power system. The detection circuit is further configured to set a bit in response to the detection of brush arcing.

[0006] According to some examples, a method involves detecting brush arcing in a power system based on an electrical signal from the power system. The method further includes setting a bit in response to the brush arc detection.

[0007] According to some examples, a system comprises a rotating shaft and one or more brushes configured to conduct electricity with the rotating shaft. The system further comprises a control unit and a detection circuit configured to detect brush arcing between the rotating shaft and the one or more brushes based on an electrical signal. The detection circuit is further configured to set a bit in response to the detection of brush arcing.

[0008] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, items, and advantages are apparent from the description, the drawings, and the claims.

[0009] Fig. Figure 1 is a basic block diagram and circuit diagram of a system comprising an AC generator, a power source and an engine according to some examples of this disclosure.

[0010] Fig. Figure 2 is a basic block diagram and circuit diagram of a system comprising an AC generator, a power source and an engine control unit according to some examples in this disclosure.

[0011] Fig. Figure 3 is a basic block diagram of a brush arc occurring between a brush and a rotor, according to some examples of this revelation.

[0012] Fig. Figure 4 is a graphical comparison of two curves of electrical signals that may indicate brush fire, according to some examples in this revelation.

[0013] Fig. Figure 5 is a principle block diagram and circuit diagram of a detection circuit according to some examples of this disclosure.

[0014] Fig. Figure 6 is a principle block diagram and circuit diagram of a detection circuit coupled to an antenna, according to some examples of this disclosure.

[0015] Fig. Figure 7 shows a user diagnostic interface that displays an output indicating one or more features of brush fire, according to some examples in this disclosure.

[0016] Fig. Figure 8 is a flowchart illustrating an example process for detecting a brush fire, according to some examples from this revelation.

[0017] Fig. Figure 9 is a basic block diagram of an AC generator control IC that communicates with a machine control unit, according to some examples of this revelation.

[0018] Fig. Figure 10 is a principle block diagram of an AC generator control IC outside the brush holder according to some examples of this revelation.

[0019] Fig. Figure 11 is a principle block diagram of an AC generator control IC with an integrated contact-based brush fire detector according to some examples of this disclosure.

[0020] Fig. Figure 12 is a principle block diagram of an AC generator control IC with an integrated wireless brush fire detector according to some examples of this revelation.

[0021] Fig. Figure 13 is a principle block diagram of an AC generator control IC with a discrete wireless brush fire detector according to some examples of this revelation.

[0022] Fig. Figure 14 is a basic block diagram of an AC generator control IC with an evaluation unit, according to some examples of this disclosure.

[0023] Fig. 15 is a flowchart illustrating an example process for validating a brush fire according to some examples of this revelation.

[0024] Brush arcing can damage components within power systems, including brushes. For example, brush arcing can cause high levels of electromagnetic radiation, which can affect the performance of nearby components. Brush arcing can also cause spikes in the excitation current through a rotor. Furthermore, brush arcing can reduce the output voltage that the AC generator can supply to a battery or other electrical loads in the system.

[0025] A power system, such as an AC generator, can be designed to withstand spikes in the excitation current caused by brush arcing. Design modifications to an AC generator can make the brushes more resistant to aging and can make the generator more resilient to potential damage caused by brush arcing. In particular, an AC generator control IC can be designed to withstand sharp voltage spikes at an excitation pin. However, these designs can only mitigate the potential damage from brush arcing without preventing future arcing. A user can prevent future arcing by replacing a faulty brush, but the user may not notice the faulty brush without access to diagnostic information that would indicate arcing.

[0026] Detecting brush arcing in an AC generator or other power system can be difficult if the arcing occurs inside the generator during operation. This disclosure describes techniques for detecting, monitoring, and reporting an unintentional interruption of current flow through a mechanical connection, known as brush arcing, in a power system such as an AC generator, an electric generator, or an electric motor. According to some examples, these techniques include sensing an electrical signal generated by brush arcing and reporting the brush arcing to a user.The system can detect sparking caused by separation between a brush and a slip ring by detecting electric fields, magnetic fields, or a combination thereof, or by detecting a sharp change in current. The spark detector can detect coupled interference and validate the repetition of electrical signals with a defined signature, which may indicate brush arcing. Using these techniques, a diagnostic system can inform the user of brush arcing, allowing the user to replace a faulty brush or brush holder and prevent further damage to the AC generator and adjacent components.

[0027] Fig. 1 is a basic block diagram and circuit diagram of a system 2 , which is an alternating current generator 4 , a source of power 6 and a machine 8exhibits, according to some examples in this revelation. In the system 2 It can be any electromechanical system that converts mechanical energy into electrical energy, such as an automobile, a generator, a locomotive, a watercraft, or any other electromechanical system. The system 2 can further, in Fig. Includes 1 component not shown.

[0028] The AC generator 4 mechanical energy can be converted into electrical energy for the system 2 convert. According to some examples, the alternating current generator can be 4 This could be a similar machine for converting mechanical energy into electrical energy, such as a dynamo, a magneto, or a generator. According to some examples, the alternating current generator could be... 4to be a machine for converting electrical energy into mechanical energy, such as an electric motor.

[0029] The AC generator 4 can be from a machine 8 mechanical energy is obtained in the form of a rotating shaft, such as a crankshaft. The machine 8 The speed of the AC generator can be regulated by the angular velocity of the rotating shaft via a pulley and / or belt. For example, the rotating shaft can have an angular velocity of 1,500 revolutions per minute (RPM), which will cause the AC generator to 4 This can cause it to operate at a proportional angular velocity that may be three times higher than the machine's RPM. With the machine 8 It could be an internal combustion engine, a hybrid combustion-electric motor, or another suitable machine.

[0030] The AC generator 4 Can electrical power be supplied to the power source? 6 and on loads 10 spend at the power source 6 It could be a battery or an electrical energy storage device. The power source 6 can provide an initial amount of electrical energy to start the machine 8 and the AC generator 4 to start when the system 2 starts up. During the operation of the machine. 8 can the AC generator 4 mechanical energy from the machine 8 convert into electrical energy to power the power source 6 to recharge.

[0031] The burdens 10 Can any subsystems within the system 2 , which consume electrical energy. According to some examples where the system is 2When it comes to a motor vehicle, the loads can 10 It includes heating and cooling, radio and video displays, power steering, electric windows, and other subsystems. The alternator 4 can generate an electrical AC signal and rectify the AC signal using a rectifier bridge 12 convert it into a direct current ("DC") signal in order to send it to the power source 6 and the burdens 10 to supply.

[0032] The AC generator can contain an integrated circuit ("IC") 14 It includes a multi-pin AC generator control module with input and output pins. These pins can include an excitation pin ("EXC"), a local network connection pin ("LIN"), a ground pin ("GND"), a phase pin ("PH"), and a battery pin ("VBA").

[0033] The AC generator control IC can be controlled via the EXC pin. 14 an output voltage of the AC generator14 The AC generator control IC regulates the output by changing an electrical signal known as the excitation current. 14 It can use a pulse-width modulated (PWM) controlled voltage signal to vary the excitation current. The EXC pin can be connected to one or more coils or windings in the rotor. 16 be connected so that the excitation current passes through the rotor 16 is running. The EXC pin can be connected via one or more brushes (in Fig. (1 not shown) with the rotor 16 be connected.

[0034] The AC generator 4 may have one or more brushes to assist the rotor 16 to supply an excitation current. As described in more detail below, this can be done at the transition point between a brush and the rotor. 16Brush arcing can occur. Brush arcing can be caused by many reasons, including brush deformation or faulty brush holders. If brush arcing occurs, the AC generator control IC may be damaged. 14 It receives an electrical signal at the EXC pin. The AC generator control IC 14 can detect brush firing based on the electrical signal and a bit such as a machine control unit ("ECU") 22 set. According to some examples, the AC generator control IC can 14 a control unit for reading the bit that detects brush firing, or the ECU 22 can read the bit.

[0035] The LIN pin on the AC generator control IC 14 can be done via a LIN bus 20 to the ECU 22 be connected. In automotive applications, the LIN bus can be used. 20It may be connected to other components in a car, such as a steering wheel, seats, climate controls, and other components. If the system is 2 Even if it is not an automotive system, the system can still establish a connection between the AC generator control IC. 14 and the ECU 22 , which are similar to the LIN bus 20 is included.

[0036] The GND pin on the AC generator IC 14 can be referenced to a reference mass in the system 2 be connected. According to some examples, the reference mass can be the potential of a vehicle chassis or the potential of another material in the system. 2 correspond. The AC generator 4 can be via a ground connection 28be connected to the reference ground. The term "reference ground" generally refers to any known reference voltage or potential and does not necessarily correspond to any specific voltage level.

[0037] The PH pin on the AC generator control IC 14 can be applied to two or more of the phases of the stator windings 18 It must be connected. The AC generator control IC 14 Two or more phases of the stator windings can be connected via the PH pin. 18 monitor. According to some examples, the PH pin can be connected directly to the stator windings. 18 , which can contain three phases, are connected. The stator windings 18 can be based on a through the rotor 16 generated, rotating magnetic field induces a current in the rectifier bridge 12 conduct. The stator windings 18 can send an AC signal with one or more phases to the rectifier bridge 12, which can convert the AC signal into a DC signal. The capacitor 14 It can smooth the DC signal if the DC signal crosses the battery line. 26 runs along to reach the power source 6 to charge or to supply electricity to loads 10 to deliver.

[0038] The VBA pin of the AC generator control IC 14 can be connected to the battery cable 26 It must be connected. The AC generator control IC 14 Can the voltage on the battery cable 26 measure and the excitation current supplied by the AC generator control IC 14 via the EXC pin to the rotor 16 delivers, adjust. Thus, the AC generator control IC can 14 form a closed-loop feedback network, where the AC generator control IC 14 the voltage on the battery cable 26 by adjusting the excitation current to a precise value.

[0039] The AC generator control IC 14 Can a brush fire occur in the AC generator? 4 detect via the EXC pin or another source. Brush arcing can occur in the rotor. 16 at or near the connection between the rotor 16 and one or more brushes (in Fig. (1 not shown) occur. The AC generator control IC 14 can be achieved by receiving a signal from the rotor 16 in the AC generator 4 Brush arcing can be detected via the EXC pin. According to some examples, the AC generator control IC can detect this. 14 an antenna (in Fig. (1 not shown) to use to receive an electromagnetic signal generated by a brush spark.

[0040] In response to the detection of brush arcing, the AC generator control IC can 14 in a storage facility (in Fig. (1 not shown) set a bit, e.g., an error flag, to indicate that brush arcing has been detected. In response to the brush arcing detection, the AC generator control IC can 14 In a storage device such as a status register, a flip-flop, or a state machine, a bit is set. The bit can contain multiple bits that allow one or more properties of the brush firing to be determined, such as the peak amplitude, duration, frequency, or the number of detected brush firings.

[0041] According to some examples, the control unit can receive the bit from the AC generator control IC. 14 read. The control unit, such as the ECU, 22 can, by determining the status of the bit from the AC generator control IC 14 requests to work as a master. The AC generator control IC 14It can operate as a slave by responding to the control unit with a signal indicating the status of the bit that detects whether brush arcing has occurred. This signal can be a data transmission and / or an electrical signal from the AC generator control IC. 14 This bit can be used to communicate with the control unit. It can indicate the status of the AC generator control IC. 14 reveal themselves.

[0042] Without a detection circuit, the system 2 , unless the brush fire is affecting the AC generator 4 preventing a suitable voltage from being applied to the battery line 26 to produce a brush fire within the AC generator 4 It may not be recognized or detected. Brush arcing can affect the output voltage of the AC generator. 4 to the battery cable 26reduce. According to some examples, the power source can 6 have a nominal value of twelve volts, and the recharging of the power source 6 It can provide at least thirteen or fourteen volts from the battery lead. 26 required. Therefore, the AC generator control IC can 14 , when the AC generator 4 no suitable voltage at the battery cable 26 Provided, by measuring the output voltage at the VBA pin, brush arcing can be detected. However, the voltage at the battery lead can vary. 26 for many reasons other than brush arcing, which makes it difficult for the AC generator control IC to determine the cause of the voltage reduction at the battery lead. 26 to determine.

[0043] However, a brush fire may reduce the maximum available power or the power supplied by the AC generator. 4generated output voltage to the battery line 26 not significantly reduced. According to some examples, the effect of the AC generator 4 The maximum available power generated drops before the output voltage of the AC generator. Therefore, other techniques for detecting and reporting brush arcing to a user of the AC generator may not be suitable. 4 This can be advantageous, even if the brush arcing affects the AC generator. 4 If it does not prevent the generator from outputting the appropriate voltage, brush arcing can damage the AC generator. 4 and damage nearby components. Brush arcing can generate electromagnetic waves and uneven excitation currents that can damage the AC generator. 4and damage nearby components. Therefore, it is advantageous for a detection circuit to detect brush arcing even when the brush arcing affects the voltage on the battery lead. 26 not significantly reduce.

[0044] Fig. 2 is a basic block diagram and circuit diagram of a system 40 , which is an alternating current generator 4 , a source of power 6 and a machine control unit 22 as shown in some examples of this revelation. In the system 40 It can be any electromechanical system that includes a power system for converting mechanical energy into electrical energy, such as an automobile, a generator, a locomotive, a watercraft, or any other electromechanical system. The system 40 can be similar to the system 2 according to Fig. 1, and there can be one or more in Fig. Includes 2 components not shown.

[0045] The AC generator control IC 14 and the brush 44A can be in the brush holder 42 , which is located within the alternating current generator 4 can be located, are located. The alternating current generator 4 can also have a rotor 16 , stator windings 18 , and a rectifier bridge 12 exhibit. The AC generator control IC 14 , similar to the AC generator IC 14 in Fig. 1, have several pins such as EXC, LIN, GND and VBA.

[0046] Two or more brushes 44 can supply an excitation current from the AC generator control IC 14 to the rotor 16 supply. One or more spring-loaded brush holders 42 can each of the brushes 44 against the rotor 16push. The EXC pin of the AC generator control IC 14 can be used with two or more brushes 44 such as the brush 44A be connected, and the GND pin can be connected to a brush. 44B be connected. Within the AC generator control IC 14 Can the EXC pin be connected to a switch? 46A , 46B and, via a capacitor 48 , to a brush fire detection circuit 50 be connected.

[0047] At the switches 46 It could be a transistor or any other analog or digital device that conducts electricity based on a control signal. The switch 46A can be based on a control signal at a control node of the switch 46A such as a gate or base, conducting electricity from the VBA pin to the EXC pin. The VBA pin can be connected to the output of the AC generator. 4be connected. The switch 46B Based on a control signal, it can direct electricity from the GND pin to the EXC pin. The switches can be opened and closed. 46 the one over the brush 44A to the rotor 16 regulate the supplied excitation current.

[0048] If on one of the brushes 44 If brush arcing occurs, the AC generator control IC may be damaged. 14 an electrical signal that allows brush arcing to be detected, from the EXC pin of the AC generator control IC 14 received. The brush fire detection circuit 50 The signal indicating brush arcing can be transmitted via the capacitor 48 received at the EXC pin. The capacitor 48It can act as part of an optional filter circuit that differentiates the electrical signal to block low-frequency signals and allow higher-frequency signals to pass. Brush arcing can start and end quickly, generating a high-frequency signal at the EXC pin. As a result, the capacitor can 48 Allowing the signal indicating brush firing to pass through, while blocking other signals.

[0049] As an alternative or supplement to the capacitor 48 Can the brush fire detection circuit 50 a signal indicating brush arcing, transmitted via an antenna 52 detect. The antenna 52 The antenna can have a bipolar structure or a ring structure with one or more windings. 52It can be any structure capable of detecting electromagnetic fields, such as electric fields, magnetic fields, or a combination thereof. A brush spark can generate an electromagnetic wave that propagates to the antenna. 52 spreads out. The antenna 52 It can receive the electromagnetic wave and convert it into an electrical signal. The antenna 52 The electrical signal can then be sent to the brush spark detection circuit. 50 transmitted. Either the antenna 52 or the capacitor 48 or a combination or modification of one or both can cause brush arcing in the AC generator 4 detect. According to some examples, the brush spark detection circuit can 50 only to one of the antenna 52 or the capacitor 48 and not be connected to both components.

[0050] The brush fire detection circuit 50 It may include a filter circuit to distinguish between electrical signals associated with brush arcing and other electrical signals. For example, the brush arcing detection circuit may 50 It includes a debouncing circuit to distinguish between brush sparks and other electrical signals and electromagnetic waves unrelated to brush sparks.

[0051] If the brush fire detection circuit 50 If a brush arc is detected, the AC generator control IC can 14 In a memory device, a bit, e.g., an error flag, is set to indicate the event. The AC generator control IC 14 can set a bit so that the ECU 22 It can read via the LIN bus, a CAN bus, or another transmission method. A microchip 54 in the ECU 22, which includes AC generator-related software ("SW") 56 It can contain the status of the bit in the AC generator control IC. 14 The bit can read data relating to the bit and / or a brush firing fault flag, along with other fault flags in the AC generator control IC. 14 included. The ECU 22 can access the memory device to determine if the brush fire detection circuit 15 has set an error flag.

[0052] The ECU 22 Can diagnostic information that detects brush firing be sent to an on-board diagnostic system? 58 , which may contain a user interface. The on-board diagnostics can be accessed via this user interface. 58 Inform a user about brush arcing. On-board diagnostics. 58 can during an inspection or if the system 40This is an automotive system that, during a workshop visit, will produce an error output. The error output can contain data relating to fault flags set by the AC generator control IC. 14 to the ECU 22 were sent, refer to.

[0053] Fig. 3 is a basic block diagram of a brush firing system 60 , that between a brush 44A and a rotor 16 occurs, according to some examples of this revelation. The rotor 16 can turn on the spot while the brush holder 42 and the brush 44A They can be stationary. Depending on the power system and the brush, the brush can 44A an electric current to the rotor 16 conduct or draw an electric current from the rotor 16 received. In the example of an alternating current generator, the rotor can 16have one or more internal windings that carry the excitation current and generate a rotating magnetic field.

[0054] The brush holder 42 can use a spring to brush 44A against the rotor 16 to press. If the brush 44A in contact with the rotor 16 is located, the brush 44A an excitation current to or from the rotor 16 lead to. If between the brush 44A and the rotor 16 , possibly due to a defect in the brush 44A or the brush holder 42 , a gap exists between the brush 44A and the rotor 16 A potential difference can occur. Depending on the potential difference, the size of the gap, and other factors, brush arcing can occur. 60 appear.

[0055] At the brush fire 60It could be an electric arc through air or another insulating material between the brush. 44A and the rotor 16 trade. The brush fire 60 can be based on one or more properties of the brush fire 60 such as the duration of the brush fire 60 or the peak amplitude of the current or voltage in the brush spark 60 generate an electromagnetic wave. The brush fire 60 can also the excitation current that passes through the brush 44A and the rotor 16 running, influence. The brush fire 60 can cause a spike in the amplitude of the excitation current.

[0056] Fig. 4 is a graphical comparison of two curves 70 , 76 of electrical signals that may indicate brush arcing, according to some examples in this revelation. The curve 70can display an electrical signal with three pulses. The vertical axis of the curve 70 It can represent the amplitude of an electric current or an electric voltage. The horizontal axis of the curves 70 , 76 can represent time.

[0057] An AC oscillation 72 This can represent an electrical signal indicative of, or caused by, brush arcing. Brush arcing can cause high and steep voltage spikes that appear at the EXC pin of an AC generator control IC. Under normal operating conditions, the voltage at the EXC pin may be stable. According to some examples, this can be due to the AC oscillation. 72 electrical signal shown through the brush 44A to the AC generator control IC 14 running. During AC oscillation 72It could also be an electrical signal from an antenna receiving an electromagnetic oscillation generated by brush arcing. For each pulse in the curve 70 can the amplitude of the AC oscillation 72 The amplitude rises and then, after reaching the peak, can fall. Similar to the curve... 70 As shown, each pulse can have a rise time and a fall time.

[0058] In the smoothed curve 74 It could be a smoothed approximation of the amplitude of the AC oscillation. 72 trade. The smoothed curve 74 This can occur after the AC oscillation 72 has passed through a filter circuit. The filter circuit may contain an AC-DC converter and / or an impedance element with a time constant.

[0059] The curve 76 This provides an example of the width of each pulse in the curve. 70 each pulse in the curve.76 shows a time period during which the smoothed curve 74 exceeds an amplitude threshold. The curve 76 The pulse repetition time of the pulses in the curve is also shown. 70 The pulse repetition time can measure the frequency of brush firing. The pulse widths in the curve 76 can be determined by the duration during which the amplitude of the smoothed curve 74 It is measured if it is higher than a threshold amount.

[0060] Fig. 5 is a basic block diagram and circuit diagram of a detection circuit 80 according to some examples from this revelation. The detection circuit 80 It can be located within an AC generator control IC, within a brush holder, on a battery lead, within an AC generator or power system, or at any other suitable location. The detection circuit 80may contain a circuit designed to receive an electrical signal from a detector 82 , indicating brush arcing. The detection circuit 80 It can furthermore be configured to measure one or more properties of the electrical signal, such as peak amplitude, duration, or frequency. The properties of the electrical signal can also include the excitation current, the number of pole pairs, or the rotor's rotational speed. The detection circuit 80 can be an AC / DC converter 84 and an impedance element 86 contain.

[0061] At the detector 82 It could be an antenna or a filter circuit such as an antenna. 82 or a capacitor 48 in Fig. 2. Act. At the antenna. 52It could be a contactless detector, and the capacitor 48 It could be a contact-based detector. The detector 82 can operate outside the detection circuit 80 The detector can be located. 82 The detector must be positioned at a suitable distance from the brushes to receive the electromagnetic wave from the brush spark. It can also be used as a filter circuit. 82 It includes a capacitor connected to the EXC pin of an AC generator control IC. The EXC pin can receive the electrical signal from the brush, and the detector 82 It can filter or differentiate the electrical signal and send it to the detection circuit. 82 transmit. According to some examples, the detector can 82It may be connected to the EXC pin, an internal node, the VBA pin, the battery line, or a gate terminal of an excitation switch. The detector 82 It can be located in the AC generator control IC, in the brush holder, or near the brushes, such as on top of the brush holder. The detector 82 It can be located outside the AC generator, for example on the battery line, on the ECU, or at any node or block where the AC generator control IC receives a coupled signal, such as the gate driver at the EXC pin. The detector 82 can be connected to a gate of one or more internal power switches within the AC generator control IC.

[0062] The AC / DC converter 84 in the detection circuit 80It can convert the electrical signal from a high-frequency AC signal into a low-frequency signal. As in Fig. As shown in Figure 4, the incoming signal can be a sinusoidal curve such as an AC oscillation. 72 , which defines a signal amplitude that changes over time. The AC / DC converter 84 can convert the electrical signal into a low-frequency signal that defines a signal amplitude similar to the amplitude of the AC signal.

[0063] The impedance element 86 The low-frequency signal that the AC / DC converter can 84 outputs, smoothing. The impedance element 86 can, based on the resistance and reactance of the impedance element 86 , generate a time constant that can be coupled to a reference ground such as the GND pin of an AC generator control IC. If the impedance element 86a resistor and a capacitor together with components 88 , 90 , 92 , 94 exhibits that the time constant can be proportional to the product of a resistance and a capacitance of the impedance element. 86 be. As in Fig. As shown in section 4, the AC / DC converter can 84 and the impedance element 86 a low-frequency signal, for example as a smoothed curve 74 , outputting a signal resembling a shark fin with a relatively short rise time and a longer fall time. The output low-frequency signal can be applied to the electrical AC input signal, as shown in Fig. 4 as AC oscillation 72 shown, based on. Together, the AC / DC converter 84 and the impedance element 86 It can function as a filter circuit or as a smoothing circuit. According to some examples, the impedance element can 86 part of a peak detector 88 and / or an envelope detector90 be the impedance element 86 can be used to switch between the AC / DC converters 84 and the peak detector 88 , the envelope detector 90 , a period detector 92 and an event counter 94 Whether or not they are coupled.

[0064] The peak detector 88 , the envelope detector 90 , the period detector 92 and the event counter 94 They can determine and store one or more characteristics of the brush firing. The peak detector 88 can be used for each of the detection circuits 80 The received electrical signal determines the peak amplitude. The envelope detector 90 can be used for each of the detection circuits 80 The received electrical signal determines the time duration. The period detector 92 The duration between detection circuits can be adjusted. 80Determine the received electrical signals. The time period between the electrical signals can be the same as the pulse repetition time in Fig. 4. The time period may be related to the frequency of brush fires. The event counter 94 can display a running counter reading of the number of items detected by the detection circuit 80 The event counter stores received electrical signals. 94 A threshold amplitude or duration can be used to determine whether each electrical signal will detect brush sparking. The threshold for detecting brush sparking can be used by the peak detector. 88 , the rotation curve detector 90 , the period detector 92 and the event counter 94 use, and the threshold can be adjusted.

[0065] The control unit 96 or the detection circuit 80 can be in a storage facility 98Store data relating to one or more properties of brush firing. According to some examples, the control unit can 96 located in an AC generator control IC or a machine control unit. The detection circuit 80 The control unit can set a bit in response to the detection of brush arcing. This bit can contain diagnostic information that indicates one or more characteristics of the brush arcing. 96 It can read the bit and output the diagnostic information indicating brush arcing to a user interface. This user interface could be a diagnostic tool that queries (or "scans") the components in a system and displays information to a user.

[0066] The storage facility 98It can be configured to store fault flags relating to brush fire or other events in a power system. The storage device 98 It can also store bits or warnings related to brush firing. The fault flags, warnings, and / or bits can contain information relating to one or more properties of the brush firing(s), such as peak amplitude, duration, frequency, and number of brush firings. The memory device 98 May contain volatile or non-volatile memory.

[0067] Fig. 6 is a basic block diagram and circuit diagram of an antenna. 102 coupled detection circuit 104 according to some examples of this revelation. The integrated circuit 100 can both the antenna 102 as well as the detection circuit 104 contained. According to some examples, the antenna can102 outside the integrated circuit 100 The integrated circuit can be located in an AC generator control IC on the battery line or at another location suitable for detecting electromagnetic waves generated by brush arcing.

[0068] As in Fig. As shown in 6, the antenna can 102 on the integrated circuit 100 The antenna is located. 102 can be similar to an antenna 52 in Fig. 2 or the detector 82 in Fig. It should be 5. The antenna 102 can be used with the detection circuit 104 be coupled so that the antenna 102 electrical signals to the detection circuit 104 can be transmitted. The detection circuit 104 can be similar to the brush fire detection circuit 50 in Fig. 2 or the detection circuit 80 in Fig. It should be 5. The antenna 102 can receive an electromagnetic wave generated by a brush fire, and the antenna 102 The antenna can convert the electromagnetic wave into an electrical signal. 102 The electrical signal can then be sent to the detection circuit. 104 , where an AC / DC converter and an impedance element convert the electrical signal, as in connection with Fig. As described in section 5, it can be converted into a smoothed low-frequency signal and transmitted. The detection circuit 104 It can be similar to the detection circuit 80 in Fig. 5 work.

[0069] Fig. Figure 7 illustrates a user diagnostic interface. 110 , which displays an output that reveals one or more characteristics of a brush fire, according to some examples from this revelation. The user diagnostic interface 110It can receive information from an on-board diagnostic system. The user diagnostic interface 110 This is an example of a means for a user to receive diagnostic information from a performance system. The user diagnostic interface 110 It can contain information concerning a power system or other components in a larger system. According to some examples, the user diagnostic interface can... 110If the power system is an AC generator, and if the larger system is an automobile, this information pertains to the performance of the AC generator, the engine, the battery, or other components within the automobile. In some examples, instead of using a diagnostic tool that connects directly to the power system, a user can receive the diagnostic information via an over-the-air update. An over-the-air update can simplify the wireless exchange of information, such as diagnostic data, between a user and a power system.

[0070] One or more properties of brush firing can include the peak amplitude of each brush fire, the duration of the brush fires, the frequency of the electrical brush fires, or the number of brush fires. As in Fig. As shown in Figure 7, the user diagnostic interface can be used.110 the user receives an error message 112 transmit the error information 112 It can instruct the user on how to respond to potential faults in a power system. For example, the fault frequency can indicate how often a given fault has occurred during all control cycles. In particular, the fault frequency can show how many brush fires have occurred in total or since the last diagnostic output. If the fault frequency is eleven, the fault may have occurred eleven times since the last diagnostic output.

[0071] The error priority can inform the user about the severity or importance of the error conditions. For example, an error priority of one may indicate a condition that has a significant impact on operational capability, so the user should stop the system immediately. An error priority of two may indicate a condition that requires an immediate service appointment. A priority of three may indicate a condition that does not require an immediate service appointment but should be corrected at the next scheduled service.

[0072] Fig. Figure 8 is a flowchart that shows an example procedure 120 , which is implemented by a detection circuit for detecting a brush spark and setting a bit, according to one or more examples of this disclosure. The method 120 from the perspective of the detection circuit 80 in Fig. 5 described, although other components such as the brush fire detection circuit 50 in Fig. 2 and the detection circuit 104 in Fig. 6 similar procedures can be carried out.

[0073] The procedure 120 according to Fig. 8 includes the detection of brush arcing in a power system based on an electrical signal from the power system ( 122 The brush spark can generate the electrical signal and transmit it to the EXC pin of an AC generator control IC. The AC generator control IC may include a filter circuit to modulate or filter the electrical signal and send it to the detection circuit. 80 to transmit. The brush spark can also generate an electromagnetic wave that an antenna can receive and convert into an electrical signal. The antenna can then transmit the electrical signal to the detection circuit. 80transmit.

[0074] The procedure 120 may also include setting a bit in response to brush spark detection ( 124 The bit can contain diagnostic information that allows one or more characteristics of the brush firing to be identified. The control unit 96 The diagnostic information indicating brush arcing can be output to a user interface. This user interface could be a diagnostic tool that queries the components in a system and displays information to a user.

[0075] Fig. Figure 9 is a basic block diagram of an AC generator control IC. 14 , which is connected to a machine control unit 22 is related, according to some examples of this revelation. The AC generator control IC 14 can be done via a communication (com) unit 132 and a COM pin connected to the ECU 22communicate. The ECU 22 A bit in the AC generator control IC can be set within a time frame or in response to a request from an error pin via the COM pin. 14 get or read.

[0076] A pole wheel generator 130 can a rotor 16 and stator windings 18 exhibit. With regard to operation, the pole-wheel generator can 130 similar to the AC generator 4 in Fig. 2 be.

[0077] Fig. Figure 10 is a basic block diagram of an AC generator control IC. 14 outside the brush holder 42 According to some examples of this revelation. The AC generator control IC 14 can be attached to a printed circuit board 140 It must be attached with two exciter pins (EXC_1 and EXC_2). The exciter pins can be brushed. 44A , 44B in the brush holder 42 be connected.

[0078] Fig. Figure 11 is a basic block diagram of an AC generator control IC. 14 with an integrated, contact-based brush fire detector 48 According to some examples of this revelation. The integrated, contact-based brush fire detector 48 can be connected to the EXC pin of the AC generator control IC 14 have a coupled capacitor. The generator 150 Can the AC generator control IC 14 exhibit. According to some examples, the generator can be 150 This refers to any power system with a brush.

[0079] Fig. Figure 12 is a basic block diagram of an AC generator control IC with an integrated wireless brush fire detector. 52 According to some examples from this revelation. A generator 160 Can a brush fire detection circuit 50 , which are connected to an integrated, wireless brush fire detector52 within the AC generator control IC 14 is connected, exhibit. The detector 52 may include a coil antenna, a dipole antenna, or any device for detecting electromagnetic signals.

[0080] Fig. Figure 13 is a basic block diagram of an AC generator control IC. 14 with a discreet wireless brush fire detector 42 According to some examples of this revelation. A generator can be a discrete wireless brush fire detector. 52 exhibit characteristics outside the AC generator control IC.

[0081] Fig. Figure 14 is a basic block diagram of an AC generator control IC. 14 with an evaluation unit 180 According to some examples of this revelation. The AC generator control IC 14It can use operating information received from any of the pins to detect brush arcing and confirm the detection of a possible brush arc. The AC generator control IC 14 By capturing operational information from the pins and internally stored data, it can verify, validate, or substantiate the detection of a possible brush arc. The operational information can include the load current through the rotor, the rotor rotation speed, the duty cycle of the stator current(s), state machine data, or data stored in memory about past events, as well as the pole pair counter reading for the AC generator. 4 and other IC input pin information. The AC generator control IC 14Brush arc detection can be validated by comparing the measured operating information with one or more threshold values. Brush arc detection may only be valid under certain conditions, such as in a specific operating state or above a certain load current. The AC generator control IC 14 This could also be the temperature of the IC or the brush holder. 42 Measure, or use optical spark detection to detect or verify brush arcing. The AC generator control IC 14 It can use operational information received from the pins to validate brush fire detection before setting a bit or an error flag. Using multiple data sources and multiple detection methods can improve brush fire detection and reduce false positives.

[0082] The evaluation unit 180It can combine information from wireless and contact-based detectors along with operational information to detect brush firing. An AC generator control unit 182 can define the excitation current and the evaluation unit 180 supply operational information. The ECU 22 can be accessed via the COM unit 132 a bit or an error flag in an AC generator control IC 14 read the bit or the error flag in the memory of the ECU. 22 save.

[0083] Fig. 15 is a flowchart that shows an example procedure 190 The validation of a brush fire is illustrated according to some examples in this disclosure. The procedure 190 from the perspective of the evaluation unit 180 in Fig. 5 described, although other components such as the brush fire detection unit 50 in Fig. 2 and the detection circuit 104 in Fig. 6 similar techniques can be performed.

[0084] The procedure 190 according to Fig. 15 contains the detection of a brush fire ( 192 ). The detector 82 can receive an electrical signal and the signal of the brush fire detection circuit 50 supply.

[0085] The procedure 190 according to Fig. 15 further includes validating the brush sparking using operating information such as duty cycle, operating state, load current and / or speed information ( 194 ). If the evaluation unit 180 If the brush fire is not validated, the process returns 190 returns to the initial stage in the detection of brush sparking. If the evaluation unit 180 A brush fire validates the evaluation unit. 180 a brush fire flag in the AC generator control IC14 , so that the ECU 22 can read ( 196 ).

[0086] The evaluation unit 180 It can prevent or reduce faulty fault detection by distinguishing electromagnetic interference caused by brush arcing from electromagnetic interference occurring without brush arcing. The evaluation unit 180 It may include suitable detection hardware, either in the form of an electronic signal filter circuit (contact-based) and / or wireless detection capabilities (i.e., an antenna). Since the AC generator control IC 14 The brush fire detection circuit may not react immediately to the brush fire event. 50 Use a detection window ranging from a few seconds to a few hours.

[0087] The following numbered examples illustrate one or more aspects of this revelation.

[0088] Example 1. A detection circuit configured to detect brush arcing in a power system based on an electrical signal from the power system. The detection circuit is further configured to set a bit in response to the detection of brush arcing.

[0089] Example 2. Detection circuit according to Example 1, wherein the detection circuit is coupled to an antenna configured to receive an electromagnetic wave generated by the brush arcing. The antenna is further configured to convert the electromagnetic wave into the electrical signal and supply the electrical signal to the detection circuit.

[0090] Example 3. Detection circuit according to any combination of Examples 1–2, wherein the antenna and the detection circuit are located in a brush holder in the power system. The brush holder is configured to press a brush against a rotor in the power system, and the power system comprises an AC generator, an electric generator, or an electric motor.

[0091] Example 4. Detection circuit according to any combination of Examples 1–3, wherein the detection circuit is coupled to a filter circuit containing a capacitor. The filter circuit is configured to receive the electrical signal that allows the brush sparking to be detected, to filter the electrical signal, and to feed the electrical signal to the detection circuit.

[0092] Example 5. Detection circuit according to any combination of Examples 1–4, wherein the filter circuit and the detection circuit are located in a brush holder in the power system. The brush holder is configured to press a brush against a rotor in the power system, and wherein the power system comprises an AC generator, an electric generator, or an electric motor.

[0093] Example 6. Detection circuit according to any combination of Examples 1–5, wherein the detection circuit is configured to detect brush arcing by receiving at least the electrical signal from the power system and measuring one or more characteristics of the electrical signal. The one or more characteristics include a peak amplitude of the electrical signal, a duration of the electrical signal, or a frequency of the electrical signal.

[0094] Example 7. Detection circuit according to any combination of Examples 1–6, further comprising an AC / DC converter and an impedance element configured to fix a time constant, wherein the impedance element is coupled between the AC / DC converter and a reference ground.

[0095] Example 8. Detection circuit according to any combination of Examples 1–7, further configured to set a bit by setting at least one fault flag in a memory device in response to the detection of brush sparking. The bit indicates one or more properties of the brush sparking, including a brush sparking duration, a brush sparking frequency, or a number of brush sparks.

[0096] Example 9. Method comprising detecting brush sparking in a power system based on an electrical signal from the power system and setting a bit in response to the detection of brush sparking.

[0097] Example 10. Method according to Example 9, wherein the detection of a brush spark comprises receiving an electromagnetic wave generated by the brush spark through an antenna and converting the electromagnetic wave into the electrical signal through the antenna.

[0098] Example 11. Method according to any combination of Examples 9–10, wherein the detection of brush sparking comprises receiving the electrical signal through a filter circuit containing a capacitor and filtering the electrical signal through the filter circuit.

[0099] Example 12. Method according to any combination of Examples 9–11, wherein setting the bit includes setting an error flag in a memory device in response to detecting the brush fire, wherein the method further includes the control unit outputting diagnostic information indicating the brush fire to a user interface based on reading the error flag, wherein the diagnostic information includes a peak amplitude of the brush fire or a number of brush fires.

[0100] Example 13. Method according to any combination of Examples 9–12, wherein the detection of brush sparking comprises converting the electrical signal into a smoothed signal and measuring one or more properties of the electrical signal, wherein the one or more properties include a peak amplitude of the electrical signal, a duration of the electrical signal, or a frequency of the electrical signal.

[0101] Example 14. System comprising: A rotating shaft, one or more brushes configured to conduct electricity with the rotating shaft, a control unit, and a detection circuit configured to detect brush arcing between the rotating shaft and the one or more brushes based on an electrical signal. The detection circuit is further configured to set a bit in response to the detection of brush arcing.

[0102] Example 15. System according to Example 14, further comprising an antenna coupled to the detection circuit. The antenna is configured to receive an electromagnetic wave generated by the brush arcing, to convert the electromagnetic wave into the electrical signal, and to transmit the electrical signal to the detection circuit.

[0103] Example 16. System according to any combination of Examples 14–15, further comprising a filter circuit coupled to the detection circuit and coupled to at least one of the one or more brushes, the filter circuit including a capacitor. The filter circuit is configured to receive the electrical signal indicating brush sparking from the at least one brush, filter the electrical signal, and transmit the electrical signal to the detection circuit.

[0104] Example 17. System according to any combination of Examples 14–16, wherein the detection circuit is configured to set the bit by setting at least one fault flag in a memory device in response to the detection of brush firing.

[0105] Example 18. System according to any combination of Examples 14–17, wherein the control unit is configured to read the bit and output diagnostic information indicating brush firing to a user interface, wherein the diagnostic information includes a peak amplitude of the brush firing or a number of brush firings.

[0106] Example 19. System according to any combination of Examples 14–18, wherein the detection circuit is configured to detect brush sparking by measuring at least one or more features of the electrical signal, wherein the one or more features include a peak amplitude of the electrical signal, a duration of the electrical signal, or a frequency of the electrical signal.

[0107] Example 20. System according to any combination of Examples 14–19, wherein the detection circuit further comprises an AC / DC converter configured to receive the electrical signal and an impedance element configured to set a time constant, the impedance element being coupled between the AC / DC converter and a reference ground.

[0108] Example 21. Controller trained to: read a bit stored by a brush arc detection circuit or an AC generator control circuit and, in response to reading the bit, generate a warning indicating the occurrence of brush arcing.

[0109] Example 22. Controller according to Example 21, wherein the controller is configured to generate the warning by outputting at least one diagnostic information indicating brush firing to a user interface, wherein the diagnostic information includes a peak amplitude of the brush firing or a number of brush firings.

[0110] Example 23. Detection circuit according to any combination of Examples 1–8, wherein the detection circuit is configured to detect brush arcing by measuring at least one operating information which specifies at least one of a load current, rotational speed, duty cycle, state machine state, pole pair counter value or pin input information.

[0111] Example 24. Detection circuit according to any combination of Examples 1–8 or 23, further configured to validate the detected brush arcing by comparing the measured operating information with a threshold value.

[0112] The techniques described in this disclosure can be implemented, at least partially, in hardware, software, firmware, or a combination thereof. For example, various aspects of the described techniques can be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuit arrangement, as well as a combination of these components. The term "processor" or "processing circuit arrangement" can generally refer to any of the foregoing logic circuit arrangements alone or in combination with other logic circuit arrangements, or to any other equivalent circuit arrangement. A hardware-based control unit can also execute one or more of the techniques of this disclosure.

[0113] This hardware, software, and firmware can be implemented within the same device or within separate devices to support the various techniques described in this disclosure. Additionally, any of the described units, modules, or components can be implemented together or separately as discrete but cooperating logic devices. The representation of various features as modules or units is intended to highlight different functional aspects and does not necessarily imply that these modules or units must be implemented by separate hardware, firmware, or software components. Rather, functionality associated with one or more modules or units can be implemented by separate hardware, firmware, or software components or integrated within common or separate hardware, firmware, or software components.

[0114] The techniques described in this disclosure can also be implemented or encoded in a manufactured article that includes a computer-readable storage medium encoded with instructions. Instructions embedded or encoded in a manufactured article that includes a computer-readable storage medium encoded with instructions can cause one or more programmable processors or other processors to implement one or more of the techniques described herein, for example, when instructions contained or encoded in the computer-readable storage medium are executed by the one or more processors.Computer-readable storage media can include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electronically erasable programmable read-only memory (EEPROM), flash memory, a hard disk, a compact disc ROM (CD-ROM), a floppy disk, a cassette, magnetic media, optical media, or other computer-readable media. In some examples, a manufactured item may incorporate one or more computer-readable storage media.

[0115] In some examples, a computer-readable storage medium may include a non-volatile medium. The term "non-volatile" can indicate that the storage medium is not realized in a carrier wave or a propagating signal. In certain examples, a non-volatile storage medium may store data that changes over time (for example, in RAM or a cache).

[0116] Several examples of this revelation have been described. Any combination of the described systems, modes of operation, or functions is provided for.

Claims

[1] Detection circuit designed to: to detect brush arcing in a power system based on an electrical signal from the power system; and to set a bit in response to the detection of brush fire. [2] Detection circuit according to claim 1, where the detection circuit is coupled with an antenna; and where the antenna is designed for: to receive an electromagnetic wave generated by the brush fire; to convert the electromagnetic wave into the electrical signal; and to transmit the electrical signal to the detection circuit. [3] Detection circuit according to claim 2, where the antenna is located in a brush holder in the power system; where the detection circuit is located in the brush holder in the power system; in which the brush holder is designed to press a brush against a rotor in the power system; and where the power system includes an alternating current generator, an electric generator or an electric motor. [4] Detection circuit according to claim 1, where the detection circuit is coupled to a filter circuit that includes a capacitor; and in which the filter circuit is designed to: to receive the electrical signal indicating brush fire; to filter the electrical signal; and to transmit the electrical signal to the detection circuit. [5] Detection circuit according to claim 4, where the filter circuit is located in a brush holder in the power system; where the detection circuit is located in the brush holder in the power system; in which the brush holder is designed to press a brush against a rotor in the power system; and where the power system includes an alternating current generator, an electric generator or an electric motor. [6] Detection circuit according to claim 1, wherein the detection circuit is configured to detect brush sparking by at least: receives the electrical signal from the power system; and measures one or more properties of the electrical signal, wherein the one or more properties include a peak amplitude of the electrical signal, a duration of the electrical signal, or a frequency of the electrical signal. [7] Detection circuit according to one of the preceding claims, further comprising: an AC / DC converter; and an impedance element designed to introduce a time constant, wherein the impedance element is coupled between the AC / DC converter and a reference ground. [8] Detection circuit according to one of the preceding claims, wherein the detection circuit is configured to set the bit by setting at least one fault flag in a storage device in response to the detection of brush firing; where the fault flag indicates one or more characteristics of the brush firing; and where one or more properties include a brush firing duration, a brush firing frequency, or a brush firing number. [9] Detection circuit according to claim 1, wherein the detection circuit is configured to detect brush arcing by measuring at least one operating information which can be inferred from at least one of a load current, a rotational speed, a duty cycle, a state of a state machine, a pole pair counter reading or a pin input information. [10] Detection circuit according to claim 9, which is further configured to validate the detected brush sparking by comparing the measured operating information with a threshold value. [11] Detection circuit according to one of the preceding claims, wherein: the recognition circuit is further configured to receive a request for the bit from the control unit; and The detection circuit is designed to output a signal indicating the status of the bit to the control unit by transmitting at least one status to the control unit. [12] Method which features: Detecting brush arcing in a power system based on an electrical signal from the power system; and Setting a bit in response to the detection of brush fire. [13] Method according to claim 12, wherein the determination of the brush fire comprises: Receiving an electromagnetic wave generated by brush firing through an antenna; and Converting the electromagnetic wave into the electrical signal using the antenna. [14] Method according to claim 12, wherein the determination of the brush fire comprises: Receiving the electrical signal through a filter circuit containing a capacitor; and Filtering the electrical signal through the filter circuit. [15] Method according to any one of claims 12 to 14, wherein the setting of the bit comprises setting an error flag in a storage device, the method further comprising: Output of diagnostic information indicating brush sparking to a user interface by the control unit and based on reading the fault flag, wherein the diagnostic information includes a peak amplitude of the brush sparking or a number of brush sparks. [16] Method according to claim 12, wherein the detection of the brush fire comprises: Converting the electrical signal into a smoothed signal; and Measuring one or more properties of the electrical signal, wherein the one or more properties include a peak amplitude of the electrical signal, a duration of the electrical signal, or a frequency of the electrical signal. [17] System which features: a rotating wave; one or more brushes designed to conduct electricity with the rotating shaft; a control unit; and a detection circuit designed to: to detect brush arcing between the rotating shaft and one or more brushes based on an electrical signal; and to set a bit in response to the detection of brush fire. [18] System according to claim 17, further comprising: an antenna coupled to the detection circuit; where the antenna is designed for: to receive an electromagnetic wave generated by the brush fire; to convert the electromagnetic wave into an electrical signal; and to supply the electrical signal to the detection circuit. [19] System according to claim 17, further comprising: a filter circuit coupled to the detection circuit and coupled to at least one of the one or more brushes, wherein the filter circuit includes a capacitor; the filter circuit is designed to: to receive the electrical signal that indicates brush fire from at least one brush; to filter the electrical signal; and to transmit the electrical signal to the detection circuit. [20] System according to any one of claims 17 to 19, in which the control unit is designed to: to read the bit; and to output diagnostic information indicating brush firing to a user interface, wherein the diagnostic information includes a peak amplitude of the brush firing or a number of brush fires.

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