Patent Description:
A latching switch may maintain a particular state (e.g., open or closed) independent of power supplied to the latching switch. However, the armature position of the latching switch can change based on a user's interaction (e.g., manual reset) with the latching switch. Regardless of the position (e.g., open or closed) of the armature of the latching switch, it may be desired to detect the position of the armature without physically examining the latching switch.

<CIT> relates to a system for controlling the force and/or motion of an electromagnetic actuator. The actuator could be a solenoid, relay, or levitating device. The drive to the coil can be linear or switching, voltage or current and the sensors measuring the system can be as simple as just a current sensor monitoring the coil current or a flux sensor. Continuous control of position can be achieved allowing magnetic levitation or the soft landing of the moving element.

<CIT> relates to an electrical assembly comprising a device. The device includes an inductive coil and an armature. The armature is arranged to be moveable between first and second positions when the inductive coil is energized. The electrical assembly further includes a detection unit which is configured to detect an inductance of the inductive coil or a characteristic that corresponds to the inductance of the inductive coil. The detection unit is further configured to determine the position of the armature based on the detected inductance or the detected characteristic.

<CIT> relates to a method and system for determining the position of the armature of a solenoid using a controller to determine the temperature of the solenoid and to indirectly determine the position of the armature without the need of an additional sensor using current sensing pulses and a solenoid capable of staying engaged due to residual magnetism after the coil has been de-energized.

<CIT> relates to a method for pulsed control of a load using an H-bridge circuit.

<CIT> relates to a driving device of a fuel injection valve for an internal combustion engine and an injector driving device.

The object of the invention is to provide an enhanced system for detecting an armature position.

In one embodiment, a system may include an armature configured to move between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact. The system may also include a coil configured receive a current, such that the current conducting in the coil is configured to magnetize a core. The magnetized core may cause the armature to move from the first position to the second position. The system may also include a control system configured to detect a position of the armature based on an inductance of the coil.

In another embodiment, a method may include sending, via circuitry, a plurality of gate signals to a plurality of switches that may cause the plurality of switches to open. The plurality of switches may be part of an H-bridge circuit. The method also includes sending, via the circuitry, a first signal to a first switch, such that the first signal is configured to cause the first switch to close. The method may then involve sending, via the circuitry, a pulse-width modulated signal to a second switch that is part of the H-bridge circuit and measuring, via the circuitry, a current conducting via the first switch while the pulse-width modulated signal is provided to the second switch. The current corresponds to a state of an actuator coil.

In yet another embodiment, a circuit may include a plurality of switches that may be part of an H-bridge circuit and a coil that may magnetize a core of an actuator based on a current conducting in the coil. The circuit may also include a diode configured to couple to the coil, a resistor configured to couple to the diode, and a switch that may couple to the resistor. The switch may close and conduct the current received from the coil.

As described above, switching devices are used in various implementations, such as industrial, commercial, material handling, manufacturing, power conversion, and/or power distribution, to connect and/or disconnect electric power from a load. For example, a number of switching devices may be used to control operations, monitor conditions, and perform other operations related to various equipment in an industrial automation system. As such, the switching devices may be used to coordinate operations across a number of devices.

With the foregoing in mind, it should be noted that the open operation of the switching device generally depends on a coil current and a core flux of a coil that induces a magnetic field in the switching device. Some types of switching devices include a latching mechanism that enable the switching device to remain in a particular position (e.g., open or closed) regardless of whether power (e.g., coil current) is present on the switching device. The latching switching device, however, can change states when a user interacts with the latching switching device using a manual reset operation or the like. Often times, when the user resets the latching switching device, a control system or other remote monitoring system may not be aware of the state (e.g., open or closed) change of the latching switching device without the use of position sensors or other hardware components that monitor the position of an armature in the switching device. As such, the present embodiments disclosed herein are related to systems and methods for detecting the armature position of a switching device without the use of position sensor hardware. Additional details with regard to determining the armature position of an armature in a switching device will be described below with reference to <FIG>.

By way of introduction, <FIG> depicts a latching solenoid <NUM> in a latched position. The latching solenoid <NUM> may be any suitable switch mechanism or electromagnetic actuator with a latching feature. As such, the latching solenoid <NUM> may include a housing <NUM>, a coil <NUM>, a magnet <NUM>, a spring <NUM>, and an armature <NUM>. The coil <NUM> may be electrically coupled to a power source that provides a current through the coil <NUM>. The current in the coil <NUM> may induce a magnetic field or flux in a core of the armature <NUM> that interacts with the magnet <NUM> and causes the spring <NUM> and the armature <NUM> to move. Indeed, the armature <NUM> may be coupled to the spring <NUM>, such that both components move together.

The latching solenoid <NUM> may also include a latching mechanism that causes the spring <NUM>, the armature <NUM>, or both to lock or latch into a fixed position. For example, <FIG> illustrates the spring <NUM> in a compressed position and the armature <NUM> pulled into the housing <NUM> of the latching solenoid <NUM>. The latching mechanism may include a hook, a groove, or some suitable mechanical feature that fixes a position of the spring <NUM> in a compressed orientation. The latching solenoid <NUM> may also be secured to a latched position using the magnet <NUM> Although the armature <NUM> and the spring <NUM> is described in a particular configuration (e.g., compressed, inside housing), the armature <NUM> and the spring <NUM> may be configured in any suitable arrangement according to a variety of embodiments for implementing the latching solenoid <NUM>.

Based on the magnetic field induced by the current in the coil <NUM>, the armature <NUM> moves between positions as shown in <FIG>.

The armature <NUM> includes a first contact that is electrically coupled to a second contact when in a latched position and to a third contact when in a de-latched position based on the movement of the armature <NUM>. As such, the latching solenoid <NUM> may act as a switch or relay controlling an electrical connection between two nodes. In some embodiments, the magnetic field induced by the current in the coil <NUM> may cause the spring <NUM> to compress and fix the armature <NUM> in a latched position, as shown in <FIG>. In this case, the latching solenoid <NUM> may be de-latched based on a user input received via a mechanical input device (e.g., button) disposed on the housing <NUM>. <FIG> illustrates an example of a latching solenoid <NUM> that includes a button <NUM> that may be used to latch or de-latch the spring <NUM> and/or the armature <NUM>.

The latching solenoid <NUM> may interface with a number of electrical components, such as low-voltage circuitry, a microcontroller/microprocessor, and the like. In addition, the button <NUM> may provide a physical component that a user may access to manually perform operations for the latching solenoid <NUM> regardless of the current present on the coil <NUM>. By way of example, the button <NUM> may be a trip or reset button for overload products. For a number of overload products (e.g., overload relays. ), power to the latching solenoid <NUM> may be lost when an overload/trip fault is present. In this condition, the button <NUM> may be used to maintain a state (e.g., latched or de-latched) of the latching solenoid <NUM> when left at rest, while allowing for user to be able to modify the position of the armature <NUM> when pressed independent of the power provided to the latching solenoid <NUM>.

With this in mind, it should be noted that although the current in the coil <NUM> may cause the armature <NUM> to move into the latched position, the removal of the current in the coil <NUM> may not cause the armature <NUM> to move again since it is latched in a fixed position. That is, the latching mechanism that mechanically latches or holds the armature <NUM> in a particular position after the core magnetizes of the armature <NUM> magnetizes, thereby causing the armature <NUM> to change positions. Alternatively, the latching mechanism may also be configured to mechanically latch or hold the armature <NUM> in a particular position after the coil <NUM> demagnetizes and the armature <NUM> changes position. In any case, the latching mechanism may be released via manual interaction by a user, thereby causing the armature <NUM> to move positions. However, as discussed above, the change in the position of the armature <NUM> may not be detected by a control system or monitor system without the use of additional sensors that monitor the position of the armature <NUM>. That is, the presence of current or the lack of the current in the coil <NUM> may not be indicative of whether the armature <NUM> is in the latched position. As such, the embodiments described herein may be used to detect the position of the armature <NUM> of the latching solenoid <NUM> without the use of additional sensors.

With this in mind, <FIG> illustrates block diagram of an armature position detection system <NUM> that may be used to detect a position of the armature <NUM> in the latching solenoid <NUM> or any suitable electromagnetic actuator. As shown in <FIG>, the armature position detection system <NUM> may include a coil drive circuit <NUM> that may provide a coil current to an electromagnetic actuator <NUM>. The electromagnetic actuator <NUM> may correspond to the latching solenoid <NUM> described above. In any case, the coil drive circuit <NUM> provides a coil current to a coil within the electromagnetic actuator <NUM> to cause a core of the electromagnetic actuator <NUM> to magnetize. The magnetic field induced by the core of the electromagnetic actuator <NUM> causes the armature <NUM> to change positions (e.g., open or close).

The armature position detection system <NUM> includes an armature position sensor circuit <NUM>. The armature position sensor circuit <NUM> generally monitors the inductance of the coil in the electromagnetic actuator <NUM> to sense the position of the armature <NUM>. The armature position sensor circuit <NUM> provides a pulse-width-modulated signal to the coil of the electromagnetic actuator <NUM> and determines the position of the armature <NUM> based on electrical properties (e.g., inductance) of the electromagnetic actuator <NUM>.

Keeping this in mind, <FIG> illustrates an example circuit <NUM> for controlling the operation of the electromagnetic actuator <NUM>. In some embodiments, the armature position detection circuit <NUM> may be implemented via the circuit <NUM>. As shown in <FIG>, the circuit <NUM> includes an H-bridge circuit <NUM> that may control a polarity of a voltage or a direction of current flow to a coil of the electromagnetic actuator <NUM>. Additionally, the circuit <NUM> includes a measurement circuit <NUM>, which may be enabled to detect a position of the armature <NUM>.

The H-bridge circuit <NUM> may be connected to an actuator coil <NUM>, which may be part of the electromagnetic actuator <NUM>. By way of operation, one side of the H-bridge circuit <NUM> may be used to trip or induce a magnetic field in the core of the electromagnetic actuator <NUM>, and the other side of the H-bridge circuit <NUM> may be used to reset or remove the magnetic field in the core of the electromagnetic actuator <NUM>. For example, <FIG> illustrates an operation in which the H-bridge circuit <NUM> is used to trip the electromagnetic actuator <NUM>. That is, a control system or any suitable computing device may supply a solenoid trip signal (e.g., high signal) to a gate of an NMOS switch <NUM> to cause the NMOS switch <NUM> to close, thereby connecting a low signal (e.g., ground) to a gate of a PMOS switch <NUM>. In turn, the PMOS switch <NUM> may close and provide a voltage to the actuator coil <NUM>. The control system may also provide a solenoid trip signal (e.g., high signal) to an NMOS switch <NUM>, thereby providing a current path from a voltage source Vcc to ground via the actuator coil <NUM>. The current supplied to the actuator coil <NUM> may magnetize the core of the electromagnetic actuator <NUM>, thereby causing the armature <NUM> to change states.

To reset the position of the armature <NUM>, the opposite side of the H-bridge circuit <NUM> may be driven, as illustrated in <FIG>. For instance, the control system may remove the solenoid trip signals (e.g., low signal) from gates of NMOS switch <NUM> and NMOS switch <NUM>. Additionally, the control system may provide solenoid reset signals (e.g., high signals) to gates of NMOS switch <NUM> and NMOS switch <NUM>. In response to receiving the solenoid reset signals, the NMOS switch <NUM> and the NMOS switch <NUM> may close, thereby connecting a low signal (e.g., ground) to a gate of the PMOS switch <NUM>. In this way, the current supplied to the actuator coil <NUM> may be reversed, as compared to the operation of the H-bridge circuit <NUM> depicted in <FIG>. The reversal of the current flow in the actuator coil <NUM> may cause the armature <NUM> to move to an opposite position, as compared to the position achieved with the circuit operation depicted in <FIG>.

In both modes of operations depicted in <FIG> and <FIG>, the measurement circuit <NUM> is disabled by connecting a low signal to a gate of NMOS switch <NUM>. That is, the coil current in the modes of operations depicted in <FIG> and <FIG> flow to a ground connection provided via NMOS switch <NUM> or NMOS switch <NUM>. However, to detect a position of the armature <NUM> using the circuit <NUM>, the control system may provide a read enable signal (e.g., high signal) to a gate of the NMOS switch <NUM>, as depicted in <FIG>.

In addition to providing the read enable signal, the control system may provide a ping signal to the NMOS switch <NUM>. The ping signal may be a pulse-width modulated signal that cycles between a high voltage value and a low voltage value over a period of time. For example, the pulse-width modulated signal may be a voltage signal provided at <NUM> and a <NUM>% duty cycle. To deactivate the operation of the H-bridge circuit <NUM>, the control system may remove the solenoid trip signals and the solenoid reset signal from the NMOS switch <NUM>, the NMOS switch <NUM>, and the NMOS switch <NUM>.

By providing the read enable signal (e.g., high signal) to the gate of the NMOS switch <NUM>, the control system may cause the NMOS switch <NUM> to close thereby providing a current path to ground for the coil current conducting within the actuator coil <NUM>. Since the ping signal consists of a pulse-width modulated signal, the coil current through the actuator coil <NUM> is pulsed through a resistive load (e.g., resistor72 ) in the measurement circuit <NUM>. Based on the voltage present at node <NUM> in the measurement circuit <NUM>, a diode <NUM> may be used to rectify or convert the voltage into a digital signal that may be measured at output node <NUM>. The voltage measured at the output node <NUM> is dependent on the inductance of the actuator coil <NUM>. With this in mind, it should be noted that the position of the armature <NUM> is also dependent on the inductance of the actuator coil <NUM>. As such, based on the detected voltage signal at the output node <NUM>, the control system or any suitable computing device may detect the position (e.g., open or closed) of the armature <NUM>. It should be noted that the diode <NUM> may be any suitable diode such as a Schottky diode, a Zener diode, or the like.

For instance, <FIG> illustrates a timing diagram <NUM> that depicts the current detected at the node <NUM> during a trip operation, a reset operation, and a measurement detection operation of the example circuit <NUM>. Referring to <FIG>, between time t0 and time t1, the solenoid reset signal may be provided to the NMOS switch <NUM> and the NMOS switch <NUM>. As such, the coil current of the actuator coil <NUM> may be a positive value (e.g., ~<NUM>. During the trip operation, the solenoid trip signal may be provided to the NMOS switch <NUM> and the NMOS switch <NUM> (solenoid reset signal removed from the NMOS switch <NUM> and the NMOS switch <NUM>). As a result, the coil current of the actuator coil <NUM> may be a negative value (e.g., ~-<NUM>.

At time t4, the measurement circuit <NUM> may be activated as described above with reference to <FIG>. As shown in <FIG>, the detected coil current during position sensing has a relatively lower magnitude, as compared to the current magnitudes during the reset operation and the trip operation. In this way, the coil current is low enough to avoid affecting the trip or reset operations of the electromagnetic actuator.

<FIG> illustrates a scaled view of the measured current at time t4. As shown in <FIG>, a first current trace <NUM> achieves a higher peak value, as compared to a second current trace <NUM>. The first current trace <NUM> may correspond to a situation in which the armature <NUM> is in an open position and the core of the electromagnetic actuator <NUM> is not magnetized. That is, since the core of the electromagnetic actuator <NUM> is not magnetized, the inductance of the actuator coil <NUM> is higher than when the core of the electromagnetic actuator <NUM> is magnetized. This lower inductance causes the peak current to be greater than the peak current of the second current trace <NUM>, which corresponds to when the armature <NUM> is in a closed position. That is, when the armature <NUM> is in the closed position, the inductance of the actuator coil <NUM> is lower than when the core of the electromagnetic actuator <NUM> is not magnetized.

Although the different peak values may be difficult to determine based on the analog values measured at the node <NUM>, the diode <NUM> may rectify the coil current received at the node <NUM> to produce digital values, as shown in <FIG>. Indeed, the first current trace <NUM>, which corresponds to armature <NUM> being in an open position may correspond to a voltage signal <NUM>. Additionally, the second current trace <NUM>, which corresponds to armature <NUM> being in a closed position may correspond to a voltage signal <NUM>. As depicted in <FIG>, the one-volt difference between the two voltage signals may be used to provide a digital indication of the position of the armature <NUM>. Namely, the high voltage level may correspond to the armature <NUM> being in an open position and the low voltage level may correspond to the armature <NUM> being in a closed position.

Although the preceding discussion of the operation of the example circuit <NUM> is detailed using NMOS switches and PMOS switches, it should be understood that any suitable switching technology (e.g., MOSFET, IGBT, BJT) may be employed to perform the operations of the circuit <NUM>. Indeed, the NMOS switches can be changed to PMOS switches, and vice-versa, so long as the gate signals change accordingly. In any case, it should be noted that the switches illustrated in <FIG> are provided as example switches, and the present disclosure should not be limited to the embodiments described in those figures.

With the foregoing in mind, the control system may remotely access or the electromagnetic actuator <NUM> to determine the position of the armature <NUM>. Indeed, the remote detection of the position of the armature <NUM> may enable users to know the state of the electromagnetic actuator <NUM> regardless of whether a user has manually changed the state of the actuator. That is, the control system may leverage the inductance of the actuator coil <NUM> to remotely determine the position of the armature <NUM>. In some embodiments, the control system may then update a visualization to be presented via a display, send a notification to another computing device, or perform any other suitable operation to provide an indication regarding the position of the armature <NUM>. In some embodiments, the control system may determine whether the detected state of the armature <NUM> matches an expected state of the armature <NUM>. If not, the control system may send solenoid trip or solenoid reset signals to respective gates of switches to cause the H-bridge circuit <NUM> to change state of the electromagnetic actuator <NUM> to match the expected state. In this way, the control system may remotely control the operation of the electromagnetic actuator <NUM>, while also remotely detecting the position of the armature <NUM> without using additional hardware.

It should be noted that the gate signals may be provided via a control system or any suitable computing device. As such, the control system may include any suitable computing system, controller, or the like. By way of example, the control system may include a communication component, a processor, a memory, a storage, input/output (I/O) ports, a display, and the like. The communication component may be a wireless or wired communication component that may facilitate communication between different components within the industrial automation system, to the electromagnetic actuator <NUM>, or the like.

The processor may be any type of computer processor or microprocessor capable of executing computer-executable code. The processor may also include multiple processors that may perform the operations described below. The memory and the storage may be any suitable articles of manufacture that can serve as media to store processor-executable code, data, or the like. These articles of manufacture may represent computer-readable media (e.g., any suitable form of memory or storage) that may store the processor-executable code used by the processor to perform the presently disclosed techniques. The memory and the storage may represent non-transitory computer-readable media (e.g., any suitable form of memory or storage) that may store the processor-executable code used by the processor to perform various techniques described herein. It should be noted that non-transitory merely indicates that the media is tangible and not a signal.

The I/O ports may be interfaces that may couple to other peripheral components such as input devices (e.g., keyboard, mouse), sensors, input/output (I/O) modules, and the like. The display may operate to depict visualizations associated with software or executable code being processed by the processor. In one embodiment, the display may be a touch display capable of receiving inputs from a user. The display may be any suitable type of display, such as a liquid crystal display (LCD), plasma display, or an organic light emitting diode (OLED) display, for example. Additionally, in one embodiment, the display may be provided in conjunction with a touch-sensitive mechanism (e.g., a touch screen) that may function as part of a control interface. It should be noted that the components described above with regard to the control system are exemplary components and the control system may include additional or fewer components as shown.

Technical effects of the embodiments described herein include providing the ability to remotely detect a position of an armature in an electromagnetic actuator without employing position sensing circuitry, such as optocouplers and the like. Indeed, the position of the armature may be detected remotely by providing a pulse-width modulated signal to the actuator coil and measuring a digital voltage output that changes based on the inductance of the actuator coil. In this way, present embodiments described herein may provide systems and methods for detecting the position of the armature without including additional sensing circuitry.

It should be noted that although certain embodiments described herein are described in the context or contacts that are part of a latching solenoid or relay device, it should be understood that the embodiments described herein may also be implemented in suitable contactors and other switching components. Moreover, it should be noted that each of the embodiments described in various subsections herein, may be implemented independently or in conjunction with various other embodiments detailed in different subsections to achieve more efficient (e.g., power, time) and predictable devices that may have a longer lifecycle. It should also be noted that while some embodiments described herein are detailed with reference to a particular relay device or contactor described in the specification, it should be understood that these descriptions are provided for the benefit of understanding how certain techniques are implemented. Indeed, the systems and methods described herein are not limited to the specific devices employed in the descriptions above.

Claim 1:
A system for detecting a position of an armature (<NUM>), comprising:
an armature comprising a first contact and configured to move between a first position that electrically couples the first contact of the armature to a second contact and a second position that electrically couples the first contact of the armature to a third contact;
a coil (<NUM>) configured to receive a current, wherein the current conducting in the coil is configured to magnetize a core, thereby causing the armature to move from the first position to the second position;
an H-bridge circuit (<NUM>) configured to provide the current to the coil;
a measurement circuit (<NUM>) configured to detect a measurement of the current, the measurement circuit comprising a resistive load (<NUM>) connected in series with the coil and a measurement switch (<NUM>) configured to close a current path to ground comprising the resistive load and the coil; and
a control system configured to detect the position of the armature based on an inductance of the coil, wherein detecting the position of the armature comprises:
sending a plurality of gate signals to a plurality of switches of the H-bridge circuit configured to cause the plurality of switches to open, thereby deactivating the operation of the H-bridge circuit;
sending a first signal to the measurement switch, wherein the first signal is configured to cause the measurement switch to close the current path to ground;
sending a pulse-width modulated signal to a first switch that is part of the H-bridge circuit; and
measuring a current conducting via the measurement switch while the pulse-width modulated signal is provided to the first switch, wherein the current corresponds to the position of the armature.