Relay protection system

Provided herein are improved relay protection systems that can detect a short to ground condition on an output of a relay. A relay protection system can bias an output of the relay. The output of the relay can be monitored to determine if a bias level reduces below a predetermined threshold, indicating a short to ground condition. If a short to ground condition is detected, the relay protection system can prevent the relay from transitioning from an open position to a closed position. As a result, a power source can remain decoupled from a load, thereby preventing damage to the relay and the load.

FIELD OF THE DISCLOSURE

This disclosure relates generally to relays, more particularly, to relay protection systems.

BACKGROUND OF THE DISCLOSURE

In many conventional relay systems, a relay transitions from an open position to a closed position to couple a high current and/or a high voltage power source to a load. If an output of the relay is erroneously shorted to ground, then when the relay is closed, the high voltage and/or high current coupled to the relay can severely damage contacts of the relay or can severely damage the load. Because these conventional relay systems transition to a closed position without knowledge of the condition of the output, the risk of significant damage is increased.

SUMMARY

Accordingly, there is a need for a relay protection system to provide protection against switching into a short to ground condition.

Various embodiments are generally directed to a relay protection system that can detect a short to ground condition on an output of a relay. The relay protection system can bias an output of the relay. The output of the relay can be monitored to determine if a bias level reduces below a predetermined threshold, indicating a short to ground condition. If a short to ground condition is detected, the relay protection system can prevent the relay from transitioning from an open position to a closed position. As a result, a power source can remain decoupled from a load, thereby preventing damage to the relay or the load.

DETAILED DESCRIPTION

FIG. 1illustrates an exemplary power distribution and control system100. The power distribution and control system100can include a power source102, a relay104, a load106, a biasing and monitoring module108, and a controller110.

The power source102can be, for example, a battery. In various embodiments, the power source102can be an automobile battery. The load106can represent electronic circuits and/or devices downstream from the power source102. These electronic components, as represented by the load106, can receive power from the power source102during normal operation of the power distribution and control system100.

The load106can be coupled to the power source102by the relay104. As shown inFIG. 1, the relay104can be coupled to the power source102and the load106can be coupled to the relay104. The relay104can be an electromagnetic relay (e.g., an electro-mechanical relay) and/or an electrically operated switch. The relay104can operate as a protection relay and/or switch. As an example, the relay104can operate to prevent or limit damage to the load106upon the occurrence of a fault condition. Fault conditions can include, for example, overvoltage or overcurrent conditions relative to the load106.

During normal operation, when a fault condition is not detected or occurring, the relay104can provide power from the power source102to the load106. When a fault condition is detected or occurs, the relay104can decouple the load106from the power source102. During such situations, the relay104can disrupt electrical connectivity between the load106and the power source102. As such, the relay104can ensure power is provided to the load106when an overvoltage or overcurrent condition is not detected or occurring (e.g., when the relay104is in a closed positioned) and can isolate and protect the load106when an overvoltage or overcurrent condition is detected or occurring (e.g., when the relay104is in an open position).

In an initial state of operation of the power distribution and control system100, the relay104can be in an open position or open state such that the power source102is not coupled to the load106. In a subsequent state of operation of the power distribution and control system100, when it is desired to provide power to the load106, the relay104can be caused to be in a closed position or enter a closed state to couple the power source102to the load106. Normal operation can be considered to be a state when the relay104couples the power source102to the load106during non-fault conditions. During normal operation, the power source102can provide a high current and/or a high voltage to the load106via the relay104.

The biasing and monitoring module108can be coupled to the relay104. The biasing and monitoring module108can determine when it is possible or desirable for the power distribution and control system100to transition from an initial state of operation (e.g., when the relay104is in an open position) to a normal state of operation (e.g., when the relay104is in a closed position). Specifically, in various embodiments, the biasing and monitoring module108can determine if it is safe to couple the power source102to the load106.

In various embodiments, the biasing and monitoring module108can determine if an output of the relay104is shorted to ground. If the output of the relay104is shorted to ground, the biasing and monitoring module108can determine that coupling the power source102to the load106is undesirable since doing so can severely damage the contacts of the relay104and/or damage other components of the power distribution and control system100(e.g., portions of the load106). Ground can be a ground voltage such as, for example, approximately zero (0) volts and/or an earth or chassis ground.

In various embodiments, the biasing and monitoring module108can also determine if the output of the relay104is not shorted to ground. If the output of the relay104is not shorted to ground, the biasing and monitoring module108can determine that coupling the power source102to the load106is possible and/or safe since doing so is unlikely to damage the contacts of the relay104and/or damage other components of the power distribution and control system100(e.g., portions of the load106).

In various embodiments, the biasing and monitoring module108can provide a bias voltage to an output of the relay104. For example, the biasing and monitoring module108can include a biasing arrangement coupled to an output of the relay104. The biasing arrangement can be monitored to determine if and when the output of the relay becomes shorted to ground (e.g., by monitoring an output of the biasing arrangement coupled to the output of the relay). The bias voltage can be a relatively low voltage. To determine if the output of the relay104is shorted to ground, the biasing and monitoring module108can monitor and/or detect the bias voltage on the output of the relay104. In various embodiments, if the biasing and monitoring module108determines that the voltage of the relay104is approximately at ground or at a voltage lower than the bias voltage, then the biasing and monitoring module108can determine that the output of the relay104is shorted to ground. Consequently, the relay104can be prevented from transitioning from an open position to a closed position as discussed above.

In various embodiments, if the biasing and monitoring module108determines that the voltage of the relay104is approximately equal to the bias voltage, then the biasing and monitoring module108can determine that the output of the relay104is not shorted to ground. Consequently, the relay104can be allowed to transition from an open position to a closed position as discussed above. The biasing and monitoring module108can include one or more components to provide the bias voltage. Further, the biasing and monitoring module108can include one or more components to detect, monitor, and/or measure the bias voltage. The components for providing and monitoring the bias voltage can be the same components. The bias voltage can be a direct current (DC) voltage.

The biasing and monitoring module108can monitor the bias voltage of the output of the relay104periodically, continuously, or randomly. For example, the biasing and monitoring module108can be configured to monitor the bias voltage periodically based on a selectable or programmable amount of time or period between monitoring. The biasing and monitoring module108can also compare a detected voltage on the output of the relay104and can compare it to one or more thresholds. A threshold can be the expected bias voltage or can be a ground. Based on the detected voltage, the biasing and monitoring module108can determine if the output of the relay104is likely shorted to ground or likely not shorted to ground. The bias and monitoring module108can include a memory for storing one or more threshold values. The memory of the biasing and monitoring module108can also store detected voltages (e.g., to maintain a log or history of detected voltages over time).

When it is determined that the output of the relay104is likely shorted to ground (e.g., when the detected voltage is below a threshold voltage approximately equal to the expected bias voltage), the biasing and monitoring module108can generate a first signal. The first signal can be provided to the controller110. The first signal can indicate that the output of the relay104is shorted to ground or likely shorted to ground (e.g., by indicating that the detected or measured voltage is below one or more predetermined thresholds).

When it is determined that the output of the relay104is likely not shorted to ground (e.g., when the detected voltage is not below a threshold voltage approximately equal to the expected bias voltage), the biasing and monitoring module108can generate a second signal. The second signal can also be provided to the controller110. The second signal can indicate that the output of the relay104is not shorted to ground or likely not shorted to ground (e.g., by indicating that the detected or measured voltage is above one or more predetermined thresholds or approximately equal to the expected bias voltage).

The controller110can control and monitor operation of the power distribution and control system100. For example, the controller110can control operation of the relay104. Specifically, the controller110can control when the relay104provides electrical connectivity between the power source102and the load106and when the relay104is to decouple the load106from the power source102.

The controller110can control the relay104based on the receipt of signals from the biasing and monitoring module108. For example, upon receipt of a signal (e.g., the first signal) from the biasing and monitoring module108that the output of the relay104is shorted to ground, the controller110can determine to prevent or block the relay104from transitioning from an open state to a closed state. That is, the controller110can ensure that the relay104does not enter a closed position and attempt to couple the power source102to the load106. In this way, damage to the relay104and/or the load106can be prevented.

Upon receipt of a signal (e.g., the second signal) from the biasing and monitoring module108that the output of the relay104is not shorted to ground, the controller110can determine to allow or enable the relay104to transition from an open state to a closed state. That is, the controller110can allow the relay104to enter a closed position so as to couple the power source102to the load106. In this way, normal operation of the power distribution and control system100can be provided, after a check of a short to ground condition is made.

When the controller110determines to prevent or block the relay104from transitioning from an open state to a closed state based on receipt of a signal from the biasing and monitoring module108(e.g., based upon receipt of the first signal described above), the controller110can also generate or provide an alarm signal. The alarm signal can be a visual and/or an audible signal. The alarm signal can alert a user, for example, that the output of the relay104is shorted to ground. In general, the alarm signal can indicate the power distribution and control system100is not operating under a normal or safe condition. The controller110can further block or prevent other operations of the power distribution and control system100.

As an alternative or in addition thereto, any signal generated by the biasing and monitoring module108based on monitoring of the output of the relay104can directly control the relay104(e.g., can prevent the relay104from closing) or can include an audible and/or visual alarm signal.

In various embodiments, the controller110can be a microprocessor. In various embodiments, the controller110can be an engine control unit (ECU) and the biasing and monitoring module108can provide any generated signal to the controller110over a controller area network (CAN) or local interconnect network (LIN).

The biasing and monitoring module108can include one or circuits and can be implemented in hardware, software, or any combination thereof. The biasing and monitoring module108and the controller110, or any portion thereof, can be considered to be part of a relay protection system.

FIG. 2illustrates an exemplary relay and biasing and monitoring system200. The relay and biasing and monitoring system200can include portions of a relay (e.g., the relay104) and a biasing and monitoring module (e.g., the biasing and monitoring module108). As shown inFIG. 2, the relay and biasing and monitoring system200can include an input connection or stud202and an output connection or stud204. The input stud202can be connected to a first portion or component of a power supply (e.g., the power source102). The output stud204can be connected to a first portion or component of a load (e.g., the load106).

As further shown inFIG. 2, the relay and biasing and monitoring system200can include a first stationary conductor or bus bar206and a second stationary conductor or bus bar208. The bus bar206can be coupled to the input stud202and the bus bar208can be coupled to the output stud204. A moveable bus bar or conductor210can be coupled between the bus bar206and the bus bar208.

The moveable bus bar or contact210can determine electrical connectivity between the bus bar206and the bus bar208. During normal operation of the relay and biasing and monitoring system200, a current (e.g., the current of the relay104) can flow from the input stud202, through the bus bar206, through the moveable conductor210, through the bus bar208, and to the output stud204. When an overvoltage or overcurrent condition is detected or occurs, the moveable conductor210can be disconnected from the bus bar206and the bus bar208, thereby disrupting the flow of current from the input stud202to the output stud204. As an example, the moveable conductor210can move in a vertical direction (relative to the orientation of the current monitoring system200as depicted inFIG. 2) so as to become disconnected from the bus bar206and the bus bar208.

Prior to a normal operational state of the relay and biasing and monitoring system200, the moveable conductor210can be disconnected from the bus bar206and the bus bar208. Once it is determined that an output of the relay is not shorted to ground (e.g., the output stud204), then the moveable conductor210can be coupled to the bus bar206and the bus bar208.

The relay and biasing and monitoring system200can further include a solenoid or coil212. Additionally, the relay and biasing and monitoring system200can include a printed circuit board (PCB)214upon which constituent components of the relay and biasing and monitoring system200can be mounted. The input stud202, the output stud204, the bus bar206, the bus bar208, the moveable conductor210, and the solenoid can form a portion of a relay (e.g., the relay104). In various embodiments, these components can form a portion of a main disconnect coupled to a power source such as, for example, a battery (e.g., an automobile battery).

The output stud204can represent an output of the relay104. As described above, a bias voltage can be applied to the output stud204and can be monitored to determine if the output stud204is shorted to ground or not. Components for providing, applying, and monitoring any bias voltage can be provided as part of the relay and biasing and monitoring system200(e.g., coupled to the PCB214). For example, the relay and biasing and monitoring system200can include all or a portion of the biasing and monitoring module108. The relay and biasing and monitoring system200can represent all or a portion of the relay104and the biasing and monitoring nodule108as depicted inFIG. 1but is not so limited. That is, the relay/circuit protection components and functions of the relay and biasing and monitoring system200and the biasing and monitoring components and functions of the relay and biasing and monitoring system200can be separated and not combined and arranged on the same PCB as depicted inFIG. 2.

FIGS. 3-6illustrate the relay and biasing and monitoring system200in a variety of views. For example,FIG. 3illustrates a first perspective view of the exemplary relay and biasing and monitoring system200andFIG. 4illustrates a second perspective view of the exemplary relay and biasing and monitoring system200.FIGS. 3 and 4are provided to illustrate an exemplary arrangement of the input stud202, the output stud204, the bus bar206, the bus bar208, the moveable conductor210, the solenoid or coil212, and the PCB214.

FIG. 5illustrates a bottom view of the relay and biasing and monitoring system200.FIG. 6illustrates a top view of the relay and biasing and monitoring system200. Again,FIG. 5andFIG. 6illustrate exemplary arrangements of the solenoid212, the bus bar206, the bus bar208, the input stud202, and the output stud204on the PCB214.

FIG. 7illustrates an exemplary flow diagram for a method for monitoring an output of a relay700. The method illustrated inFIG. 7can be implemented using the power distribution and control system100and/or the relay and biasing and monitoring system200.

At step702, an output of a relay can be biased. The output of the relay can be an output stud of the relay. The output of the relay can be provided with a bias voltage. For example, a biasing arrangement can be coupled to the output of the relay. The bias voltage can be a relatively low bias voltage.

At step704, the biasing of the relay can be monitored. The output of the relay can be monitored to detect or measure a bias voltage of the output of the relay. For example, an output of the biasing arrangement coupled to the output of the relay can be monitored to effectively monitor the output of the relay. The output of the relay can be periodically, continuously, or randomly monitored to measure or detect a bias voltage of the output of the relay. As part of the monitoring, the detected bias voltage of the relay can be compared to one or more predetermined thresholds.

At step706, a signal can be generated when the output of the relay is shorted to ground. The output of the relay can be determined to be shorted to ground when the monitored voltage of the output of the relay (or biasing arrangement) is below a predetermined threshold (e.g., the bias voltage) or is approximately equal to ground. The generated signal can indicate that the output of the relay is shorted to ground (or likely is shorted to ground). The generated signal can be provided to a microprocessor or a controller.

At step708, the relay can be prevented from closing. Specifically, the relay can be prevented from transitioning from an open position to a closed position, thereby preventing a power source from coupling to a load via the relay. In doing so, damage to the relay and/or the load can be avoided due to the shorted condition of the relay. Further, at step708, an alarm signal can be generated to indicate that the output of the relay is shorted to ground. The alarm signal can be an audible and/or a visual signal.

FIG. 8illustrates an exemplary biasing and monitoring system800. The biasing and monitoring system800can be used as part of the power distribution and control system100and/or the relay and biasing and monitoring system200and can implement part of the method for monitoring an output of a relay700.

As shown inFIG. 8, the biasing and monitoring system800can include a connector802, a biasing arrangement804, and a connector806. The connector802can be coupled to an output of a relay (e.g., an output of the relay104or the output stud204). The connector806can be coupled to a controller (e.g., the controller110). The biasing arrangement804can be an arrangement of one or more circuit components for biasing an output of a relay.

In various embodiments, the biasing arrangement804can apply a relatively low bias voltage to the output of the relay via the connector802. When the relay is not shorted to ground, a signal indicating as much can be provided to the controller by way of the connector806. For example, a signal representative of the applied bias voltage can be provided to the connector806. When the relay is shorted to ground, a signal indicating the same can also be provided to the controller by way of the connector806. For example, a low voltage (e.g., 0 V) signal can be sensed or provided at the connector806and provided to the controller.

The biasing arrangement can be implemented in hardware using internal circuitry and voltages available within a larger system that the biasing and monitoring system800operates within or as a part of.

The techniques described herein for relay protection can be applied to other circuit systems including, but not limited to, power distribution modules, battery switches, and fuse blocks. The techniques disclosed herein can reduce the likelihood of damaging circuit components caused by closing into a short to ground situation by providing the ability to detect such a situation and responding appropriately to avoid any damage that could be caused by a short to ground condition.

While the present disclosures references certain embodiments, numerous modifications, alterations and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.