EP4690426A1

EP4690426A1 - Calibration signal injection for evse calibrators

Info

Publication number: EP4690426A1
Application number: EP24719394.9A
Authority: EP
Inventors: Timothy Byron BROWN; Jake Richards
Original assignee: Fluke Corp
Current assignee: Fluke Corp
Priority date: 2023-03-24
Filing date: 2024-03-19
Publication date: 2026-02-11
Also published as: KR20250172594A; JP2026511184A; CN121175898A; WO2024205992A1

Abstract

An electric vehicle supply equipment (EVSE) calibration device includes a primary conductor, one or more calibration coils, and a current meter having one or more sensors. The current meter is coupled to the primary conductor. In an EVSE calibration mode of operation, the primary conductor conducts an EVSE current, and the current meter measures a value indicative of a first current induced in the one or more sensors by the EVSE current conducted by the primary conductor. In a second mode of operation, the one or more calibration coils conduct a calibration current, and the current meter measures a value indicative of a second current induced in the one or more sensors by the calibration current conducted by the one or more calibration coils. The sensors may include sensing coils, magnetic flux sensors, etc.

Description

CALIBRATION SIGNAL INJECTION FOR EVSE CALIBRATORS

BACKGROUND

Technical Field

The present disclosure relates to the calibration of electric vehicle supply equipment (EVSEs), also known as electric vehicle charging stations. In particular, the present disclosure relates to the calibration equipment used to verify whether a metered amount of electrical energy transferred by an EVSE is accurate.

Description of the Related Art

As mentioned above, EVSEs need to be calibrated to verify the metered amount of electrical energy transferred by the EVSE is accurate. The calibration processes, which may be specified by regulations or a standard, typically measure values of currents and voltages to determine the amount of power transferred and to verify the proper operation of the EVSE. The measured values are compared to the expected values for the EVSE. The current may typically range between zero and a large current (e.g., up to 1000 amps), and may need to be measured at multiple different current levels during the calibration process.

Current supplied by an EVSE is typically measured by an EVSE calibration device by passing the current through a conductor. As the current supplied by the EVSE passes through the conductor, it induces a current in a sensor, such as a magnetic current in a core of a sensor. A value indicative of the current induced in the sensor is measured by the calibration device, and the measured value is used to generate an indication of the current supplied by the EVSE.

The calibration processes need to be traceable to the specified regulations or standards. Thus, the calibration devices also periodically need to be calibrated, to ensure the calibration processes applied to the EVSE are accurate.

To calibrate the current measurements of the EVSE calibration device, a calibrated shunt could be employed to carry the large currents needed to calibrate the EVSE calibration device. Alternatively, a calibrated current source capable of delivering large calibrated currents could be employed to input a known current into the calibration device, without a separate calibrated shunt being required. Calibrated shunts and calibrated current sources capable of delivering large calibrated currents, however, are not common pieces of equipment. In addition, maintaining and calibrating a calibrating shunt or a calibrated current source capable of delivering large currents may be expensive and time consuming.

BRIEF SUMMARY

As mentioned above, the current supplied by an EVSE is typically measured by an EVSE calibration device by passing the current through a primary conductor, and measuring a current induced in a sensor by the current conducted through the primary conductor. For example, a magnetic current may be induced in a core of the sensor. Calibration of the EVSE calibration device typically requires passing a large current through the primary conductor, and using a calibration shunt or a calibrated current source capable of delivering large calibration currents to perform the calibration measurements.

In one aspect, instead of using large calibration currents, calibration signal injection may be employed to inject a small, calibrated current into the EVSE calibration device or calibrator, which appears to the EVSE calibration device to be much larger in magnitude than the injected calibrated current. A calibration coil of wire may be wrapped around the core of the sensor, and the small, calibrated current passed through the calibration coil of wire. The injected calibrated electrical current will induce a magnetic current in the core of the sensor of the calibration device. The induced magnetic current will appear to the sensor to be a magnetic current induced by an electrical current running through the primary conductor.

A ratio of the calibrated current to the induced magnetic current (and thus to the calibration current measurement of the EVSE calibration device) will be a function of a number of windings of the calibration coil. A large number of windings may be employed so that a small calibrated current may be employed to calibrate large current measurements by the EVSE calibration device. For example, a calibration coil having 1000 windings may be wrapped around the core of an EVSE calibration device. A one-amp calibrated current may be injected into the calibration coil to calibrate a 1000 amp reading by the calibration device.

Because a substantially smaller injected calibration current may be employed, a calibrated shunt or a calibrated current source capable of providing larger calibration currents with small uncertainty levels is not required. Instead, less expensive and more readily available calibrated current sources, such as one-amp calibrated current sources, may be employed to calibrate current measurements of the calibration device.

In an embodiment, the calibration coil may be embedded in the calibration device, and external ports provided on the calibration device for injecting the calibrated current to the calibration coil. Calibration devices (and EVSEs) are typically sealed to prevent tampering. Accessing the interior of the calibration device requires breaking the seal, which requires recalibration of the entire EVSE calibration device, and also creates the risk of exposure to dangerous voltage conditions. Embedding the calibration coil inside the calibration device and providing external ports for injecting the calibrated current facilitates calibrating the calibration device testing without breaking the seal, avoiding the need to recalibrate the calibration device, while also reducing the risk of exposure to dangerous voltage conditions.

In an embodiment, a coupling having external ports for performing current calibration and voltage calibration of an EVSE charging station calibration device may be provided on the calibration device. This facilitates performing both voltage and current calibration testing of an electric vehicle charging station calibration device using external connections, eliminating any need for disassembly of the calibration device during calibration. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Figure 1 depicts an embodiment of a system including an electric vehicle supply equipment (EVSE) calibration device.

Figure 2 is a conceptual diagram illustrating an embodiment of calibration of the EVSE calibration device of Figure 1.

Figure 3 depicts an embodiment of a system including an EVSE calibration device.

Figure 4 is a flow diagram illustrating an embodiment of a method of performing calibration operations.

DETAILED DESCRIPTION

The following description, along with the accompanying drawings, sets forth certain specific details in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that the disclosed embodiments may be practiced in various combinations, with or without one or more of these specific details, or with other methods, components, devices, materials, etc. In other instances, well-known structures or components that are associated with the environment of the present disclosure, including but not limited to interfaces, ports, meters, calibrated current sources, coils, sensors, control circuits, electric vehicles, EVSEs, in an EVSE or calibration environment, have not been shown or described in order to avoid unnecessarily obscuring descriptions of the embodiments. Additionally, the various embodiments may be methods, systems, devices, etc.

Throughout the specification, claims, and drawings, the following terms take the meaning associated herein, unless the context indicates otherwise. The term “herein” refers to the specification, claims, and drawings associated with the current application. The phrases “in one embodiment,” “in another embodiment,” “in various embodiments,” “in some embodiments,” “in other embodiments,” and other variations thereof refer to one or more features, structures, functions, limitations, or characteristics of the present disclosure, and are not limited to the same or different embodiments unless the context indicates otherwise. The term “based on” is not exclusive and allows for being based on additional features, functions, aspects, or limitations not described, unless the context indicates otherwise. In addition, throughout the specification, the meaning of “a,” “an,” “one” and “the” include singular and plural references.

For the purposes of the present disclosure, unless otherwise indicated, the phrase “A and B” is nonlimiting and means one or more of (A) and one or more of (B); the phrase “A or B” is nonexclusive and means one or more of (A), one or more of (B), or one or more of (A and B); the phrase “A and/or B” means one or more of (A), one or more of (B), or one or more of (A and B); the phrase “at least one of A and B” and the phrase “one or more of A and B” both mean one or more of (A) and one or more of (B); and the phrase “at least one of A or B” and the phrase “one or more of A or B” both mean one or more of (A), one or more of (B), or one or more of (A and B). By way of extension, for example, the phrases “at least one of A, B, or C” and “one or more of A, B, or C” both mean one or more of (A), one or more of (B), one or more of (C), one or more of (A and B), one or more of (A and C), one or more of (B and C), or one or more of (A, B and C). In the above, A, B, and C represent any form or type of element, feature, arrangement, component, structure, aspect, action, step, etc.

As mentioned above, EVSEs need to be calibrated to verify the metered amount of electrical energy transferred by an EVSE is accurate. The calibration process, which may be specified by regulations or a standard, typically requires a large amount of electrical energy to be transferred from an EVSE to the calibration equipment within a short period of time. For example, some standards require calibration testing at 85% of the maximum transfer current of the EVSE until a specific amount of power has been transferred.

Calibration devices used to calibrate EVSEs typically measure values of currents and voltages to determine an amount of power transferred and to verify the proper operation of the EVSE. The measured values are compared to expected values for the EVSE. The current may typically range between zero current and large currents (e.g., up to 1000 amps), and may need to be measured at multiple different current levels during the current calibration process.

Current supplied by an EVSE is typically measured by an EVSE calibration device by passing the current through a primary conductor. As the current supplied by the EVSE passes through the conductor, it induces a current in one or more sensors. For example, a magnetic current may be induced in a core of the sensor. A value indicative of the induced current is measured by the EVSE calibration device, and the measured value is used to generate an indication of the current supplied by the EVSE. The indication is compared to an expected value.

The calibration process needs to be traceable to the specified regulations or standards. Thus, the EVSE calibration devices also periodically need to be calibrated, to ensure the calibration processes are accurate.

To calibrate the current measurements of the EVSE calibration device, a calibrated shunt could be employed. The calibrated shunt would need to have specific resistances at specific currents and specific environmental conditions. While an uncalibrated current source may be employed with a calibrated shunt, the specific environment conditions for using the shunt would need to be met, and such environmental conditions may be different at different current levels to be measured. Calibrated shunts are not common pieces of equipment, and, thus, are not readily available. In addition, to provide accurate calibration, the shunts themselves must be periodically calibrated, tracked, and maintained in good condition.

Alternatively, a calibrated current source could be employed to input a known current into the calibration device. An unknown load or shunt may be employed, and a calibrated shunt is not required. The calibrated current source would need to be capable of delivering large calibrated currents (e.g., up to 1000 amps), with an uncertainty substantially smaller than that required under the regulations or standards for the EVSE to be calibrated using the calibration device (e.g., up to four times smaller). Such calibrated current sources are not readily available, and would be expensive to employ.

Instead of using large calibration currents, calibration signal injection may be employed to inject a small, calibrated current into the EVSE calibration device or calibrator, which appears to the EVSE calibration device to be much larger in magnitude than the injected calibrated current. One or more calibration coils may be wrapped around the sensor core, and the small, calibrated current passed through the one or more calibration coils. The injected calibrated current will induce a magnetic current in the core of the sensor of the EVSE calibration device, which will appear to the EVSE calibration device to be a current induced in the core by a current running through the primary conductor.

A ratio of the calibrated current to the injected current will be a function of a number of windings of the one or more calibration coils. A large number of windings may be employed so that a significantly smaller calibrated current may be employed to calibrate large current measurements by the EVSE calibration device. For example, a calibration coil having 1000 windings may be wrapped around the core or toroid of a calibration device. A one-amp calibrated current may be injected into the calibration coil to calibrate a 1000 amp reading by the EVSE calibration device.

Thus, calibrated shunts or calibrated current sources capable of providing larger calibration currents with small uncertainty levels are not required. Instead, less expensive and more readily available calibrated current sources, such as one-amp calibrated current sources, may be employed to calibrate current measurements of the calibration device.

The one or more calibration coils may be embedded in the calibration device, and external ports provided on the calibration device for injecting the calibrated current. EVSE calibration devices (and EVSEs) are typically sealed to prevent tampering. Accessing the interior of the EVSE calibration device requires breaking the seal, which requires recalibration of the entire EVSE calibration device. Embedding the one or more calibration coils inside the calibration device and providing external ports for injecting the calibrated current facilitates calibrating the EVSE calibration device without breaking the seal.

A coupling having external ports for conducting current calibration and voltage calibration of an electric vehicle charging station calibration device may be provided on the calibration device. The coupling facilitates performing both voltage and current calibration testing of an EVSE calibration device using a single piece of calibration equipment and a single cable.

The external ports also eliminate any need for disassembly of the EVSE calibration device during the calibration processes, while also reducing the risk of exposure to dangerous voltage conditions.

Figure 1 depicts an embodiment of a system 100, including an electric vehicle supply equipment (EVSE) 110, also known as a charging station, to provide electrical energy to an electric vehicle 120. As illustrated, the EVSE 110 includes a power coupling 112 and a charging cable 113, and the electric vehicle 120 includes a power coupling 122 and batteries 125.

In operation, electrical energy is provided by the EVSE 110 to vehicle 120 via the power coupling 112 of the EVSE, the charging cable 113, and the power coupling 122 of vehicle 120. The provided electrical energy may be used, for example, to charge batteries 125 of the electric vehicle 120.

The EVSE 110 includes control circuitry 114 to control the dispensing of electrical energy by EVSE 110, and to meter the dispensing of electrical energy by the EVSE 110. The metered amount may be displayed, for example, on display 116 of the EVSE 110. Metering is employed so that an amount of payment owned for the provided electrical energy may be determined.

As mentioned above, the EVSE 110 needs to be calibrated (e.g., periodically) to verify the metered amount of electrical energy transferred by the EVSE 110 is accurate. In the system 100 of Figure 1, an EVSE calibration device 130 is provided to calibrate the EVSE 110.

The EVSE calibration device 130 includes a meter 134 to measure the amount of electrical energy transferred by the EVSE 110 to the EVSE calibration device 130, and a display 136 to display the measured amount of electrical energy transferred. The calibration processes, which may be specified by regulations or a standard, typically require a large amount of electrical energy to be transferred from an EVSE (e.g., EVSE 110) to calibration equipment (e.g., calibration device 130) within a short period of time. For example, some standards require calibration testing at 85% of the maximum transfer current of the EVSE charging station until a specific amount of power has been transferred.

With reference to Figures 1 and 2, during calibration of the EVSE 110, electrical energy is supplied by the EVSE 110 to the EVSE calibration device 130 via the power coupling 112 of the EVSE 110, the charging cable 113, and an input coupling 132 of the EVSE calibration device 130. The charging cable 113 is shown as a dashed line in the coupling of the power coupling 112 of the EVSE 110 to the input coupling 132 of the EVSE calibration device 130 to indicate the EVSE 110 would typically not be coupled to both the electrical vehicle 120 and the EVSE calibration device 130 at the same time.

A current Ip associated with the electrical energy supplied by the EVSE 110 to the EVSE calibration device 130 is measured by passing the current Ip through a conductor 138. The current Ip induces a current in one or more sensors 140. For example, a sensor 140 may have a core 170. The conductor 138 passes through or adjacent to the core 170. The core 170 may be an air core or a magnetic core, and may be a hollow core of various shapes (e.g., a toroid, such as a donut-shaped torus). As the current Ip passes through the conductor 138, it induces a magnetic current IEVSE in the core 170. The sensor 140 senses the magnetic current IEVSE, and may employ various sensing configurations, as well as combinations of different sensing configurations.

For example, some embodiments may employ one or more sensing coils 172 wrapped around the core 170. The induced magnetic current IEVSE will induce an electrical current in the sensing coil 172. A value of the electrical current induced in the sensing coil may be measured, and serves as an indication of the induced magnetic current IEVSE. In another example, the core 170 may have one or more air gaps 174, and the sensor 140 may include magnetic flux sensors 176 to measure an indication of the induced magnetic current IEVSE. For example, Hall effect sensors, fluxgates, magnetic resistance sensors (e.g., Anisotropic Magneto-Resistive sensors (AMR), Giant Magneto-Resistive sensors (GMR), Tunnel Magneto-Resistive sensors (TMR), etc.), may be employed.

A sensed value corresponding to the induced current IEVSE is measured by the meter 134, which may be an ammeter, and the measured value is used to generate an indication of the current supplied by the EVSE 110 to the EVSE calibration device 130. The indication may be displayed on the display 136, and compared to an expected value of the indication. In an embodiment, the current meter 134 may be rated to measure currents between zero and 1000 amps. In some embodiments, the current meter 134 may advantageously be rated to measure currents between 25 and 500 amps.

The EVSE calibration device 130 also needs to be calibrated to verify the measurements performed by the EVSE calibration device to 130 to calibrate EVSEs 110 are accurate, for example within specified tolerances. The calibration of the EVSE calibration device 130 may be performed, for example, periodically. To facilitate calibration of the EVSE calibration device 130, the EVSE calibration device 130 includes one or more calibration coils 142, and a calibration coupling 144. In a current calibration mode of operation, the calibration coupling 144 is coupled to a calibrated current source 160.

The calibrated current source 160 as illustrated includes an output coupling 162, control circuitry 164 and a display 166. The control circuitry 164 controls generation of a calibrated current by the calibrated current source 160. The control circuitry 164 may perform or control other functions of the calibrated current source 160, such as generating controlled voltages, performing metering functions, etc. The calibrated current source may have a specified calibrated current range, for example, a range of 0.0 to 10 amps, a range of 0.1 to 10 amps, a range of 0.0 to 30 amps, a range of 0.01 to 30 amps, etc.

During calibration of the EVSE calibration device 130, the calibrated current source 160 provides a calibrated current Is to the EVSE calibration device 130 via the coupling 162 of the calibrated current source 160, cabling 168, and the calibration coupling 144 of the EVSE calibration device 130. The calibrated current Is is passed through a calibration coil 142. In some embodiments, multiple calibration coils 142 may be employed. For ease of reference, operation of an embodiment will be described with reference to a single calibration coil 142.

As the calibrated current Is is passed through the calibration coil 142, the injected calibrated electrical current will induce a magnetic current ICAL in the core 170 of the sensor 140 of the EVSE calibration device 130. The induced magnetic current ICAL will appear to the calibration device 130 to be a magnetic current induced by an electrical current running through the primary conductor 138 (e.g., it will appear to be induced magnetic current IEVSE).

A ratio of the calibrated current passed through the calibration coil 142 to the induced magnetic current ICAL in the sensing coil 140 (and thus to the current measurement of the EVSE calibrator 130) will be a function of a number of windings of the calibration coil 142. A large number of windings may be employed in the calibration coil 142 so that injection of a small calibrated current may be employed to calibrate large current measurements by the EVSE calibration device 130. For example, a calibration coil 142 having 1000 windings may be wrapped around the core or toroid of a calibration device 130. A one-amp calibrated current may be injected into the calibration coil 142 to calibrate a 1000 amp reading by the calibration device 130. In an embodiment, a calibration coil 142 may comprise between 100 and 1000 windings. In practice, a calibration coil having approximately 800 windings may be advantageously employed in some embodiments.

As discussed above with respect to the induced magnetic current IEVSE, a sensed value indicative of the induced current ICAL is measured by the meter 134, and the measured value is used to generate an indication of the current supplied by the calibrated current source 160 to the EVSE calibration device 130. The indication may be displayed on the display 136, and compared to an expected value of the indication.

The system 100 as illustrated also includes an optional resistive load 310, which may facilitate voltage calibration measurements, as discussed in more detail below in the discussion of Figure 3.

Embodiments of the system 100 of Figure 1 may have more elements than illustrated, may have fewer elements than illustrated, may combine illustrated elements, may split illustrated elements into multiple elements, and may be otherwise modified in various ways. For example, the EVSE calibration device 130 may comprise a voltage meter and be configured to perform voltage measurements related to electrical energy supplied by an EVSE 110 to the EVSE calibration device. In another example, the EVSE calibration device 130 may include a switch to facilitate coupling ports of the calibration coupling 144 to a calibration coil 142 or to other components of the EVSE calibration device 130, such as the primary conductor 138. In another example, the EVSE calibration device 130 may include a case with various components of the EVSE calibration device 130 contained within the case, and a seal may be applied to the case to indicate the EVSE calibration device 130 has not been compromised (e.g., opened) since the last calibration operation. In other examples, the one or more sensors or sensing coils 140 may be separate from the meter 134, or the calibration coils 142 may be included in the meter 134. The couplings 112, 132, 144, 164 may have a plurality of ports, etc.

Figure 3 illustrates an embodiment of a system 300 including an EVSE calibration device 130 and a calibrated current source 160. Similar reference numbers have been employed in Figure 3 to indicate elements similar to corresponding elements in Figures 1 and 2, and explanations of the structure and operation of such corresponding elements may be found in the discussion of Figures 1 and 2 above.

The EVSE calibration device 130 as illustrated includes a case 302 having a seal 304. The couplings 132, 144, 162 include a plurality of ports 306. An optional alternative calibration coupling configuration 144’ includes a switch 308. The system 300 as illustrated also includes an optional resistive load 310, which may facilitate voltage calibration measurements, as discussed in more detail below.

The seal 304 applied to the sealed case 302 restricts access to components of the EVSE calibration device 130, such as the display 136, the meter 134, the sensor 140, the calibration coil 142, the primary conductor 138, the switch 308 and internal connections to the ports 306 of the input coupling 132 and the calibration couplings 144 and 144’. The couplings 132, 144, 144’ may provide external access to the ports 306 to facilitate coupling the EVSE calibration device 130 to other devices, such as the calibrated current source 160 or an EVSE (see EVSE 110 of Figure 1). The case may provide restricted access to other components of the EVSE calibration device 130. For example, the display 136 may be visible through case, external control devices (not shown), such as switches, etc., may be configurable without opening the case 302 and breaking the seal 304. The integrity of the seal 304 applied to the case 302 may indicate the EVSE calibration device 130 has not been compromised (e.g., opened) since the last calibration operation.

In an embodiment, the coupling 144 includes two externally accessible currentcalibration ports 306c coupled to the calibration coil 142, and two optional externally accessible voltage-calibration ports 306v coupled to the primary conductor 138. In an alternative embodiment, the coupling 144’ includes two externally accessible ports 306’, which in operation may be selectably coupled by the switch 308 to perform calibration operations. For example, the two externally accessible ports 306’ may be coupled to the calibration coil 142 via the switch 308 to facilitate current calibration operations using calibration signal injection. The two externally accessible ports 306’ may be coupled to the primary conductor 138 and optional resistive load 310 via the switch 308 to facilitate voltage calibration operations, which may be performed in an otherwise conventional manner. The two externally accessible ports 306’ may be disconnected by the switch 308 from internal components of the EVSE calibration device 130 in other modes of operation, such as when the EVSE calibration device 130 is performing calibration operations with respect to an EVSE (see EVSE 110 of Figure 1).

Embodiments of the system 300 of Figure 3 may have more elements than illustrated, may have fewer elements than illustrated, may combine illustrated elements, may split illustrated elements into multiple elements, and may be otherwise modified in various ways. For example, the EVSE calibration device 130 or the calibrated current source 160, or both, may comprise a voltage meter and be configured to perform voltage measurements. In another example, the sensor 140, the calibration coils 142, or both, may be included in the meter 134.

Figure 4 illustrates an embodiment of a method 400 of performing calibration operations, which may be employed, for example, using the EVSE calibration device 130, the calibrated current source 160, or both, of the system 100 of Figure 1, or the system 300 of Figure 3. Figure 4 will be described with reference to Figures 1-3.

The method 400 begins at 402, for example, to perform periodic calibration operations associated with calibrating an EVSE calibration device 130, or to perform other operations, such as calibrating of an EVSE 110. The method 400 proceeds from 402 to 404. At 404, the method 400 determines whether to perform current calibration operations associated with calibrating the EVSE calibration device 130. When it is not determined at 404 to perform current calibration operations associated with calibrating the EVSE calibration device 130, the method 400 proceeds from 404 to 406, where other calibration operations associated with calibrating the EVSE calibration device 130 or associated with calibrating an EVSE 110, may be performed. For example, the EVSE 110 may be calibrated using the EVSE calibration device 130 as discussed above with reference to Figures 1 and 2.

When it is determined at 404 to perform current calibration operations associated with calibrating the EVSE calibration device 130, the method 400 proceeds from 404 to 408. At 408, the method 400 sets up the EVSE calibration device 130 and the calibrated current source 160 to perform the current calibration operations associated with calibrating the EVSE calibration device 130. This may be done, for example, by coupling ports 306 of the coupling 162 of the calibrated current source 160 to ports 306c of the coupling 144 of the EVSE calibration device 130, and configuring the calibrated current source 160 to generate the calibrated current. In some embodiments, the ports 306 of the coupling 162 of the calibrated current source 160 may be coupled to ports 306’ of the coupling 144’ of the EVSE calibration device 130, and switch 308 controlled to couple the ports 306’ to the calibration coil 142, instead of coupling ports 306 of the coupling 162 of the calibrated current source 160 to ports 306c of the coupling 144 of the EVSE calibration device 130. The method 400 proceeds from 408 to 410. At 410, the method 400 generates a calibrated calibration current for injection into the EVSE calibration device 130. The calibration current may be generated in a convention manner using the calibrated current source 160. The method 400 proceeds from 410 to 412.

At 412, the method 400 injects the generated calibration current into the EVSE calibration device 130. This may be done, for example, by conducting the calibration current through the calibration coil 142 of the EVSE calibration device 130. The method proceeds from 412 to 414.

At 414, the method 400 measures an indication of a current in the EVSE calibration device 130 induced by the injected calibration current. This may be done, for example, using the sensor 140 and the meter 134, such as described above. The method proceeds from 414 to 416.

At 416, the method 400 determines whether a value of the measured indication of the induced current is within a threshold range of an expected value of the measured indication of the induced current. The expected value may be based on a value of the calibration current. Lookup tables may be employed. The threshold range may typically be 2 percent of the expected value of the calibrated current. Other threshold ranges may be employed, such 0.1 percent of the expected value of the calibration current.

When it is not determined at 416 that the measured indication of the induced current is within the threshold range of the expected value of the measured indication of the induced current, the method 400 proceeds from 416 to 418, where a calibration determination is made that current measurements by the EVSE calibration device 130 are not within a tolerance. In some embodiments an indication of the determination that current measurements by the calibration device are not within tolerance may be transmitted (e.g., to a remote server (not shown), uploaded to a calibration application, etc.), displayed (e.g., on display 136 or display 166 of Figure 1), documented (e.g., by printing and affixing a seal 304 to the case 302 indicating current measurements by the EVSE calibration device 130 are not within tolerance, removing or breaking a seal 304 indicating the EVSE calibration device 130 is within tolerance, documenting in a paper, such as a calibration report), etc., and various combinations thereof. The method proceeds from 418 to 424, where other operations may be performed, such as initiating adjustment of the EVSE calibration device 130, recalibration of the EVSE calibration device 130, other operations associated with calibrating the EVSE calibration device 130, etc. and various combinations thereof. For example, in some embodiments, the method 400 proceeds from 418 to 420, where the EVSE calibration device 130 optionally may be adjusted in response to the determination current measurements by the EVSE calibration device 130 are not within tolerance. For example, the EVSE calibration device 130 may be adjusted at 420 based on a comparison of the measured indication of the induced current to the expected value of the measured indication of the induced current. In some embodiments, the adjustment at 420 may include adjusting an offset to be applied to current measurements performed by the EVSE calibration device. The method 400 returns to 402 from 420, where calibration processes for the adjusted EVSE calibration device 130 may be performed or repeated. The optional adjustment and recalibration of the EVSE calibration device 130 is illustrated in Figure 4 using dashed lines.

When it is determined at 416 that the measured indication of the induced current is within the threshold range of the expected value, the method 400 proceeds from 416 to 422, where it may be determined in a calibration determination that current measurements by the EVSE calibration device 130 are within tolerance or partially within tolerance, and the determination that the current measurements by the EVSE calibration device 130 are within tolerance or partially within tolerance may be transmitted, displayed, documented, or various combinations thereof, such as discussed above. The method proceeds from 422 to 424, where other operations may be performed, such as documentation of any adjustments performed at 420 in a previous calibration loop, other operations associated with calibrating the EVSE calibration device 130 (e.g., voltage measurement calibration operations), etc. and various combinations thereof.

Embodiments of the method 400 of Figure 4 may contain additional acts not shown in Figure 4, may not contain all of the acts shown in Figure 4, may perform acts shown in Figure 4 in various orders, may combine acts, may split acts into separate acts, and may be otherwise modified in various respects. For example, Figure 4 may be modified to combine acts 410, 412 and 414, to perform acts 404, 408, 410, 414, 416, 420 and 422 without breaking the seal 304, etc. and various combinations thereof.

In light of the foregoing description, the following non-exclusive list of examples illustrates particular implementations of systems and methods that are contemplated by the present disclosure.

Example 1 : An electric vehicle supply equipment (EVSE) calibration device, optionally comprising: a primary conductor, which, in an optional EVSE calibration mode of operation, conducts an EVSE current; one or more calibration coils, which, in an optional second mode of operation, conducts a calibration current; and a current meter having one or more sensors, optionally coupled to the primary conductor, wherein, in the EVSE calibration mode of operation, the current meter measures a value indicative of a first current induced in the one or more sensors by the EVSE current conducted by the primary conductor; and in the second mode of operation, the current meter measures a value indicative of a second current induced in the one or more sensors by the calibration current conducted by the one or more calibration coils.

Example 2: Example 1, wherein optionally, the one or more sensors comprise a core, and the one or more calibration coils are wrapped around the core.

Example 3: Example 2, wherein optionally, the core is a toroid.

Example 4: Example 1, wherein optionally, the one or more sensors comprises a magnetic flux sensor, which, in operation, measures magnetic flux.

Example 5: Example 1, wherein optionally, the one or more calibration coils comprise between 100 and 1000 windings.

Example 6: Example 5, wherein optionally, the current meter is rated to measure currents in the primary conductor between twenty-five and 1000 amps.

Example 7: Example 1, optionally comprising a coupling including externally accessible calibration ports, wherein, in the second mode of operation, the one or more calibration coils receive the calibration current via one or more of the externally accessible calibration ports of the coupling.

Example 8: Example 7, wherein the coupling optionally includes: one or more externally accessible current-calibration ports, wherein in the second mode of operation, the one or more calibration coils receive the calibration current via the externally accessible current-calibration ports.

Example 9: Example 8, wherein the coupling optionally includes: one or more voltagecalibration ports coupled to the primary conductor.

Example 10: Example 7, optionally comprising a switch, wherein the switch, in the second mode of operation, couples one or more external accessible calibration ports of the coupling to the one or more calibration coils.

Example 11 : Example 7, optionally comprising a case having a seal, the seal restricting access to internal components of the EVSE calibration device.

Example 12: Example 1, optionally comprising a case having a seal.

Example 13: A system, optionally comprising: a calibrated current source; and an electric vehicle supply equipment (EVSE) calibration device optionally including: a conductor; a current meter having one or more sensors and one or more calibration coils, wherein, in an optional EVSE calibration mode of operation: the conductor is configured to conduct an EVSE current; and the current meter is configured to measure a value indicative of a first current induced in the one or more sensors by the EVSE current; and in an optional second mode of operation: the EVSE calibration device is coupled to the calibrated current source; the one or more calibration coils are configured to conduct a calibration current generated by the calibrated current source; and the current meter is configured to measure a value indicative of a second current induced in the one or more sensors by the calibration current.

Example 14: Example 13, wherein optionally the current meter is rated to measure currents up to a maximum current, and the maximum current is at least 500 amps. Example 15: Example 14, wherein optionally, the calibrated current source, in operation, is configured to generate calibrated currents up to a maximum calibration current, wherein the maximum calibration current is less than 30 amps.

Example 16: A method of calibrating an electric vehicle supply equipment (EVSE) calibration device, optionally comprising: generating, using a calibrated current source, a calibration current; conducting the calibration current through one or more calibration coils of the EVSE calibration device; measuring a value indicative of a current induced in the EVSE calibration device by the calibration current conducted through the one or more calibration coils; determining whether the measured value indicative of the current induced in the EVSE calibration device is within a threshold range of an expected value, the expected value being based on the calibration current; and transmitting or causing a display of a calibration determination based on the determination of whether the value of the measured value indicative of the current induced in the EVSE calibration device is within the threshold range of the expected value.

Example 17: Example 16, optionally comprising documenting the calibration determination.

Example 18: Example 16, wherein the generating the calibration current optionally comprises generating a maximum calibration current of less than 10 amps.

Example 19: Example 16, wherein the determining whether the measured value is within the threshold range of the expected value optionally comprises determining whether the measured value is within 2 percent of the expected value.

Example 20: Example 16, wherein the determining whether the measured value is within the threshold range of the expected value optionally comprises determining whether the measured value is within 0.5 percent of the expected value of the measured current.

Example 21 : An electric vehicle supply equipment (EVSE) calibration device (130), optionally comprising: a primary conductor (138), which, in an optional EVSE calibration mode of operation, conducts an EVSE current; one or more calibration coils (142), which, in an optional second mode of operation, conduct a calibration current; and a current meter (134) having one or more sensors (140), coupled to the primary conductor (138), wherein, in the EVSE calibration mode of operation, the current meter (134) measures a value indicative of a first current induced in the one or more sensors (140) by the EVSE current conducted by the primary conductor (138); and in the second mode of operation, the current meter (134) measures a value indicative of a second current induced in the one or more sensors (140) by the calibration current conducted by the one or more calibration coils (142).

Example 22: Example 21, wherein the one or more sensors (140) optionally comprise a core (170), and the one or more calibration coils (142) optionally are wrapped around the core (170), optionally, the core is a toroid.

Example 23: Any of Examples 21 and 22, wherein the one or more sensors (140) optionally comprises a magnetic flux sensor (176), which, in operation, measures magnetic flux. Example 24: Any of Examples 21-23, wherein the one or more calibration coils (142) optionally comprise between 100 and 1000 windings, optionally, the current meter (134) is rated to measure currents in the primary conductor (138) between twenty-five and 1000 amps.

Example 25: Any of Examples 21-24, optionally comprising a coupling (132, 144, 162) including externally accessible calibration ports (306, 306c, 306v), wherein, in the second mode of operation, the one or more calibration coils (142) receive the calibration current via one or more of the externally accessible calibration ports (306, 306c, 306v) of the coupling (132, 144, 162).

Example 26: Example 25, wherein the coupling (132, 144, 162) optionally includes: one or more externally accessible current-calibration ports (306c), wherein in the second mode of operation, the one or more calibration coils (142) receive the calibration current via the externally accessible current-calibration ports (306c), optionally, the coupling (132, 144, 162) includes one or more voltage-calibration ports (306v) coupled to the primary conductor (138).

Example 27: Any of Examples 25 and 26, optionally comprising a switch (308), wherein the switch (308), in the second mode of operation, couples one or more external accessible calibration ports (306, 306c, 306v) of the coupling (132, 144, 162) to the one or more calibration coils (142).

Example 28. Any of Examples 21-27, optionally comprising a case (302) having a seal (304), preferably, the seal (302) restricting access to internal components (134, 136, 138, 140, 142, 146, 170, 172, 174, 176) ofthe EVSE calibration device (130).

Example 29: A system (100, 300), optionally comprising: a calibrated current source (160); and an electric vehicle supply equipment (EVSE) calibration device (130) optionally including: a conductor (138); a current meter (134) having one or more sensors (140) and one or more calibration coils (142), wherein, in an optional EVSE calibration mode of operation: the conductor (138) is configured to conduct an EVSE current; and the current meter (134) is configured to measure a value indicative of a first current induced in the one or more sensors (140) by the EVSE current; and in an optional second mode of operation: the EVSE calibration device (130) is coupled to the calibrated current source (160); the one or more calibration coils (142) are configured to conduct a calibration current generated by the calibrated current source (160); and the current meter (134) is configured to measure a value indicative of a second current induced in the one or more sensors (140) by the calibration current.

Example 30: Example 29, wherein, the current meter (134) optionally is rated to measure currents up to a maximum current, preferably, the maximum current is at least 500 amps, and preferably, the calibrated current source (160), in operation, is configured to generate calibrated currents up to a maximum calibration current, preferably, the maximum calibration current is less than 30 amps.

Example 31 : A method (400) of calibrating an electric vehicle supply equipment (EVSE) calibration device (130), optionally comprising: generating (410), using a calibrated current source (160), a calibration current; conducting (412) the calibration current through one or more calibration coils (142) of the EVSE calibration device (130); measuring (414) a value indicative of a current induced in the EVSE calibration device (130) by the calibration current conducted through the one or more calibration coils (142); determining ( 16) whether the measured value indicative of the current induced in the EVSE calibration device (130) is within a threshold range of an expected value, the expected value being based on the calibration current; and transmitting or causing a display of a calibration determination (418, 422), based on the determination of whether the value of the measured value indicative of the current induced in the EVSE calibration device is within the threshold range of the expected value.

Example 32: Example 31, optionally comprising documenting (418, 422) the calibration determination.

Example 33: Any of Examples 31 and 32, wherein the generating (410) the calibration current optionally comprises generating a maximum calibration current of less than 10 amps.

Example 34: Any of Examples 31-33, wherein the determining (416) whether the measured value is within the threshold range of the expected value optionally comprises determining whether the measured value is within 2 percent of the expected value.

Example 35: Any of Examples 31-33, wherein the determining whether the measured value is within the threshold range of the expected value optionally comprises determining whether the measured value is within 0.5 percent of the expected value of the measured current.

It should be understood that the various embodiments described above can be combined to provide yet further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.

Claims

1. An electric vehicle supply equipment (EVSE) calibration device, comprising: a primary conductor, which, in an EVSE calibration mode of operation, conducts an EVSE current; one or more calibration coils, which, in a second mode of operation, conduct a calibration current; and a current meter having one or more sensors, coupled to the primary conductor, wherein, in the EVSE calibration mode of operation, the current meter measures a value indicative of a first current induced in the one or more sensors by the EVSE current conducted by the primary conductor; and in the second mode of operation, the current meter measures a value indicative of a second current induced in the one or more sensors by the calibration current conducted by the one or more calibration coils.

2. The EVSE calibration device of claim 1, wherein the one or more sensors comprise a core, and the one or more calibration coils are wrapped around the core, optionally, the core is a toroid.

3. The EVSE calibration device of any of the preceding claims, wherein the one or more sensors comprises a magnetic flux sensor, which, in operation, measures magnetic flux.

4. The EVSE calibration device of any of the preceding claims, wherein the one or more calibration coils comprise between 100 and 1000 windings, optionally, the current meter is rated to measure currents in the primary conductor between twenty-five and 1000 amps.

5. The EVSE calibration device of any of the preceding claims, comprising a coupling including externally accessible calibration ports, wherein, in the second mode of operation, the one or more calibration coils receive the calibration current via one or more of the externally accessible calibration ports of the coupling.

6. The EVSE calibration device of claim 5, wherein the coupling includes: one or more externally accessible current-calibration ports, wherein in the second mode of operation, the one or more calibration coils receive the calibration current via the externally accessible current-calibration ports, optionally, the coupling includes one or more voltagecalibration ports coupled to the primary conductor.

7. The EVSE calibration device of any of claims 5 and 6, comprising a switch, wherein the switch, in the second mode of operation, couples one or more external accessible calibration ports of the coupling to the one or more calibration coils.

8. The EVSE calibration device of any of the preceding claims, comprising a case having a seal, preferably, the seal restricting access to internal components of the EVSE calibration device.

9. A system, comprising: a calibrated current source; and an electric vehicle supply equipment (EVSE) calibration device including: a conductor; and a current meter having one or more sensors and one or more calibration coils, wherein, in an EVSE calibration mode of operation: the conductor is configured to conduct an EVSE current; and the current meter is configured to measure a value indicative of a first current induced in the one or more sensors by the EVSE current; and in a second mode of operation: the EVSE calibration device is coupled to the calibrated current source; the one or more calibration coils are configured to conduct a calibration current generated by the calibrated current source; and the current meter is configured to measure a value indicative of a second current induced in the one or more sensors by the calibration current.

10. The system of claim 9, wherein, the current meter is rated to measure currents up to a maximum current, preferably, the maximum current is at least 500 amps, and preferably, the calibrated current source, in operation, is configured to generate calibrated currents up to a maximum calibration current, preferably, the maximum calibration current is less than 30 amps.

11. A method of calibrating an electric vehicle supply equipment (EVSE) calibration device, comprising: generating, using a calibrated current source, a calibration current; conducting the calibration current through one or more calibration coils of the EVSE calibration device; measuring a value indicative of a current induced in the EVSE calibration device by the calibration current conducted through the one or more calibration coils; determining whether the measured value indicative of the current induced in the EVSE calibration device is within a threshold range of an expected value, the expected value being based on the calibration current; and transmitting or causing a display of a calibration determination based on the determination of whether the value of the measured value indicative of the current induced in the EVSE calibration device is within the threshold range of the expected value.

12. The method of calibrating an EVSE calibration device of claim 11, comprising documenting the calibration determination.

13. The method of calibrating an EVSE calibration device of any of claims 11 and 12, wherein the generating the calibration current comprises generating a maximum calibration current of less than 10 amps.

14. The method of calibrating an EVSE calibration device of any of claims 11-13, wherein the determining whether the measured value is within the threshold range of the expected value comprises determining whether the measured value is within 2 percent of the expected value.

15. The method of calibrating an EVSE calibration device of any of claims 11-13, wherein the determining whether the measured value is within the threshold range of the expected value comprises determining whether the measured value is within 0.5 percent of the expected value of the measured current.