System and method for pre-charge testing to prevent misuse of electric vehicle charging stations - Patents.com

Abstract

To provide a system and a method for preventing misuse of a charging station for electric vehicles.SOLUTION: In a system 10, a charging station 14 for charging an electric vehicle 12 includes: a power supply 36 that supplies re-charging electric power to one or more energy accumulation devices 16 on the electric vehicle; and a charging device 38 that controls energy transmission to the electric vehicle from the power supply. The charging device supplies a control pilot signal to a vehicle control circuit 20 of the electric vehicle, measures a voltage level of the control pilot signal at the time of connection of the electric vehicle to the charging station, executes a selected pre-charging test routine on the basis of the measured voltage level of the control pilot signal, and allows charging of the electric vehicle from the power supply upon compliance with the selected pre-charging test routine that was executed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate generally to charging electric vehicles, and more particularly, to a system and method for preventing misuse of an electric vehicle charging station. implements a pre-charge test procedure to provide flexible charging permissions that accommodate different types of electric vehicles while meeting desired safety and efficiency standards. [Background technology]

[0002] Electrically powered vehicles, such as electric cars and plug-in hybrid electric vehicles, offer a zero-emission or low-emission solution for urban transportation and are expected to gradually replace internal combustion engine vehicles as the primary means of transportation in the future. Electrically powered vehicles include an electric motor that is powered by an energy storage device, such as a battery. As the vehicle operates, the energy storage device housed in the vehicle becomes emptied. To enable further use of the vehicle, the energy storage device is typically recharged by electric vehicle supply equipment (EVSE) or a "charging station", which is designed to charge the energy storage device when connected to the vehicle.

[0003] It is well understood that charging stations are designed to comply with harmonized standards (i.e., International Electrotechnical Commission (IEC) standards) that incorporate features to prevent the charging station from powering anything other than a conforming electric vehicle. One such feature or test used to prevent misuse of such charging stations is a pilot diode test, which interacts with and checks a pilot diode D included in the control pilot circuit 2 of the electric vehicle 4, as shown in FIG. 1, to determine if the vehicle complies with the required standard. Checking for the presence of this diode D is one method that can be used to prevent misuse of the charging station 6 or to prevent accidental powering of the charging station if the charging plug becomes wet (e.g., if there is standing water on the ground).

[0004] Another feature or test used in charging stations to prevent misuse of the charging station is a sequence test, which can be used separately from or in combination with the pilot diode test. In a sequence test, a series of events / conditions that must be met to initiate charging is set, and the sequence generally progresses as follows: State A (electric vehicle is not connected to the charging station) → State B (electric vehicle is connected to the charging station but not ready to charge) → State C (electric vehicle is connected to the charging station and ready to charge). An example of state B is when the charging station requires authorization before charging is allowed (e.g., RFID or mobile app authorization) but has not given such authorization, e.g., the charging station does not oscillate the control pilot signal. In state C, the charging station is given authorization to allow charging and enables charging, e.g., generates an oscillating pilot signal that is fed to the control pilot circuit 2 and closes switch S2 in the control pilot circuit, as shown in FIG. 1.

[0005] While many charging stations typically use both the pilot diode test and the sequence test before allowing charging of an electric vehicle, it is recognized that in some cases, the execution of both tests is not required to allow charging. That is, the IEC standard specifies that for small electric vehicles under 16A, a "simplified control pilot circuit" as shown in Figure 2 should be utilized, which includes a pilot diode but does not include switch S2 as in Figure 1. For such vehicles, the sequence test does not need to be performed so that "simplified charging" can be performed instead. To allow for the possibility of performing such simplified charging, charging stations have been designed that allow equipment owners to install a configuration option in the EVSE. Such configurations were initially limited to simplify charging, but gradually the configuration options were expanded to not only disable the sequence test, but also to disable the pilot diode test as an alternative. That is, the charging station owner is given the choice of which of the two tests to use. Thus, in one configuration, the charging station performs the pilot diode test but does not perform the sequence test (i.e., abbreviated charging), and in another configuration, the charging station skips the pilot diode test but performs / executes the sequence test.

[0006] It is recognized that while the configuration implemented by the charging station owner is suitable for environments and situations where the charging station is used repeatedly to charge only a single vehicle (i.e., personal or residential), such configuration may be problematic and / or inefficient when the charging station is a public charging station. That is, because public charging stations are utilized by many different types of vehicles (i.e., both vehicles requiring standard charging and vehicles requiring only simplified charging), the charging station cannot be configured once and left configured because certain vehicles may not comply with the test employed, leaving the charging station unable to be used to recharge those vehicles, and a charging station configured to provide simplified charging and simply perform a pilot diode test cannot provide higher amperage charging. A possible workaround for frequently reconfiguring the charging station is to simply disable both the pilot diode test and the sequence test, but configuring the charging station in such a manner is not recommended as it potentially enables misuse of the charging station and may compromise safety.

[0007] It is therefore desirable to provide a charging station and method of operation that employs pre-charge testing to prevent misuse of the charging station. It is further desirable that such tests performed by the charging station be performed in an automated manner so as to enable charging of multiple electric vehicle types while maintaining the safety and efficiency associated with charging operations. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 9,725,005 Summary of the Invention

[0009] According to one aspect of the invention, a charging station for charging an electric vehicle is provided that includes one or more energy storage devices and a vehicle control circuit having a pilot diode. The charging station includes a power source operable to provide recharging power to one or more energy storage devices of the electric vehicle, and a charging device configured to control energy transfer from the power source to the electric vehicle. The charging device is configured to provide a control pilot signal to the vehicle control circuit of the electric vehicle, the control pilot signal being received by the vehicle control circuit upon connection of the electric vehicle to the charging station. The charging device is also configured to measure a voltage level of the control pilot signal upon connection of the electric vehicle to the charging station, execute a selected pre-charge test routine based on the measured voltage level of the control pilot signal, and enable charging of the electric vehicle from the power source upon compliance with the executed selected pre-charge test routine.

[0010] According to another aspect of the present invention, a method of pre-charge testing for authorizing use of an electric vehicle charging station is performed by a charging device of the electric vehicle charging station, the method including the steps of: upon detecting connection of a load to the electric vehicle charging station, providing a control pilot signal to the load, and determining a state of the load charging cycle based on the control pilot signal, the load charging cycle including at least state A, state B, and state C, each defined by a different control pilot signal voltage level; The method also includes performing a pilot sequence test if the charge cycle progresses from state A to state B upon connection of the load to the electric vehicle charging station, performing a pilot diode test if the charge cycle progresses from state A to state C upon connection of the load to the electric vehicle charging station, and enabling charging of the load from the electric vehicle charging station upon completion and compliance of one of the performed pilot sequence test or pilot diode test.

[0011] According to yet another aspect of the present invention, a charging station for charging an electric vehicle is provided, the charging station including a state driver circuit configured to generate and provide a control pilot signal to a vehicle control circuit of the electric vehicle, a detection circuit configured to measure a voltage level of the control pilot signal responsive to providing the control pilot signal to the vehicle control circuit, and a processor, the processor being programmed to: determine a state of charge associated with the electric vehicle based on the measured voltage level of the control pilot signal, execute a first pre-charge test routine if the voltage level of the control pilot signal is a first voltage level, execute a second pre-charge test routine if the voltage level of the control pilot signal is a second voltage level, and enable charging of the electric vehicle from the charging station upon completion and compliance of one of the executed first pre-charge test routine or the second pre-charge test routine.

[0012] Various other features and advantages will be made apparent from the following detailed description and the drawings.

[0013] The drawings illustrate preferred embodiments presently contemplated for carrying out the invention.

[0014] The description of the drawings is as follows: [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram of a control pilot circuit included in an electric vehicle, as known in the prior art; [Diagram 2] 1 is a block diagram of a simplified control pilot circuit included in an electric vehicle, as known in the prior art; [Diagram 3] FIG. 1 is a block diagram of an exemplary electric vehicle charging station that can be used in embodiments of the present invention to provide charging to electric vehicles. [Figure 4]4 is a flow chart illustrating an automatic pre-charge test scheme performed by the electric vehicle charging station of FIG. 3 to permit charging of electric vehicles and to prevent misuse of the electric vehicle charging station in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Embodiments of the present invention relate to a system and method for preventing misuse of an electric vehicle charging station. The charging station performs an automatically determined pre-charge test procedure to provide flexible charging permissions that accommodate different types of electric vehicles while meeting desired safety and efficiency standards.

[0017] In many embodiments, the term "electric vehicle" is used to refer to a vehicle that includes one or more electric motors used for propulsion. The energy used to propel an electric vehicle can come from a variety of energy storage devices, such as, but not limited to, on-board rechargeable batteries, capacitors, and / or on-board fuel cells. In one embodiment, the electric vehicle is a hybrid electric vehicle and can include both an electric motor and a combustion engine. In another embodiment, the electric vehicle is an electric vehicle and can include only an electric motor for propulsion. An electric vehicle can use energy generated, for example, by braking, to generate power. In addition, some electric vehicles can recharge the energy storage device from a power receptacle, such as a power outlet. Thus, as used herein, the term "electric vehicle" can refer to any vehicle that includes an energy storage device that is supplied with electrical energy, for example, via a power grid.

[0018] Referring first to FIG. 3, an exemplary system 10 for charging an electric vehicle 12 is shown. In an exemplary embodiment, the system 10 includes a charging station 14 coupled to the electric vehicle 12. The electric vehicle 12 includes at least one energy storage device 16 coupled to a motor 18. The energy storage device 16 may include, for example, one or more batteries, capacitors, inductors, etc. In an exemplary embodiment, the electric vehicle 12 includes a vehicle control circuit 20 coupled to the energy storage device 16. The vehicle control circuit 20 communicates with the charging station 14 and is responsible for controlling the transfer of energy from the charging station 14 to the energy storage device 16. In an exemplary embodiment, the vehicle control circuit 20 includes a pilot diode 22, resistors 24, 26, and a switching device 28, as described in more detail below. The pilot diode 22 on the electric vehicle 12 is intended to be a typical small signal silicon diode, and a reverse voltage rating of at least 100V is recommended since this diode is directly exposed to cable transients. The switching device 28 may be a mechanical switch or a relay, or may be a solid-state switch such as a FET.

[0019] The electric vehicle 12 is coupled to the charging station 14 via a charging conduit 30 configured to transfer power from the charging station 14 to the vehicle 12. The charging conduit 30 may be coupled to the vehicle 12 at a charging receptacle 32 via a connector 34, which may be a 5-pin (not shown) connector conforming to the SAE J1772 standard, for example, with contacts 1 and 2 for AC power lines, contact 3 for equipment ground, contact 4 for control pilot signals (status voltages and reference signals), and contact 5 for proximity detection. According to an embodiment, the charging conduit 30 may include at least one conductor for providing electrical energy to the energy storage device 16 and / or other components within the vehicle 12, and at least one conductor for transmitting information to and / or receiving information from the vehicle control circuitry 20 and / or any other components within the vehicle 12. Additionally or alternatively, the charging conduit 30 may include a cable with one or more conductors for providing electricity to the vehicle 12 without a separate, dedicated conductor for transmitting information to and from the vehicle 12. In such embodiments, information may be embedded in one or more power signals transmitted between vehicle charging station 14 and vehicle 12 via charging conduit 30 .

[0020] In an exemplary embodiment, charging station 14 includes a power source 36 and a charging device 38 connected to power source 36. As shown, charging device 38 includes a processor 44, a state driver circuit 46 coupled to processor 44, and a detection circuit 48 coupled to each of processor 44 and state driver circuit 46. Processor 44 includes memory 50, which may be integrated with processor 44 or may be separate from processor 44 in other charging device embodiments. The state driver circuit is configured to provide a control pilot voltage signal to node A to provide a state voltage to vehicle control circuit 20. In an exemplary embodiment, state driver circuit 46 is configured to provide + / -12V to node A, and state driver circuit 46 includes a positive voltage branch 52 for providing +12V to node A and a negative voltage branch 54 for providing -12V to node A. As shown, the positive voltage branch 52 and the negative voltage branch 54 are substantially balanced so that the response time of each branch 52, 54 to a state voltage command from the processor 44 is substantially the same.

[0021] In an exemplary embodiment, charging device 38 may be configured to: The charging device 38 is configured to control the transfer of energy from the power source 36 to the electric vehicle 12 (e.g., by opening or closing a contactor 51), and such state of charge is determined / confirmed by performing what is hereinafter referred to as a "pilot sequence test" and / or a "pilot diode test." Prior to controlling the energy transfer, the charging device 38 determines a charge cycle state associated with the electric vehicle 12 based on state voltages provided between and affected by each of the charging station 14 and the electric vehicle 12. More specifically, the state voltages are voltages affected by the charging device 38 and / or the vehicle 12 and are indicative of a charge cycle state associated with the electric vehicle 12. In an exemplary embodiment, the detection circuit 48 detects the state voltages, and the processor 44 determines a state of charge associated with the electric vehicle 12 based on the detected state voltages.

[0022] Various electric vehicle charging cycle states, typically defined by SAE J1772 or the like, are represented by different voltages on the pilot signal, including: state A (electric vehicle not connected), represented by 12 volts; state B (electric vehicle connected but not ready to accept energy, as described below; sub-states B1 and B2 are possible); state C (electric vehicle connected and ready to accept energy, no ventilation of the indoor charging area is required), represented by 6 volts; state D (electric vehicle connected and ready to accept energy, ventilation of the indoor charging area is required), represented by 3 volts; state E (charging station not connected, utility power unavailable, or other charging station problem), represented by 0 volts; and state F (charging station unavailable, or other charging station problem), represented by -12 volts. With regard to the voltages above, it is recognized that the stated values ​​are approximate voltages and in practice the standards allow a tolerance of a few tenths of a volt (e.g., up to + / - 0.7V) from the stated / nominal value, i.e. the voltage may be equal or substantially equal to the stated 0V / 3V / 6V / 9V / 12V values ​​and more expensive / precision components would not be required.

[0023] In operation of the charging station 14, the processor 44 provides state voltage commands to the state driver 46, which may be either high (e.g., 0V) or low (e.g., 5V). In the absence of a condition that would provide a low state voltage command (e.g., error, fault, test, etc.), the processor 44 provides a high state voltage command, which causes the state driver 46 to provide a +12V control pilot voltage signal to node A. According to an embodiment of the present invention, upon connecting the electric vehicle 12 to the charging station 14, the processor 44 determines an appropriate pre-charge test scheme to employ to ensure that charging can be safely provided, as described in more detail below. A more detailed description of the pilot sequence test and pilot diode test that may be performed by the processor 44 is first described below.

[0024] When performing a pilot sequence test, the sequence test proceeds from a state where the electric vehicle 12 is not connected to the charging station 14 (State A) to a state where the vehicle 12 is connected to the charging station 14. Upon such connection, when the diode 22 and resistor 24 are coupled to the charging device 38 and the state voltage command is high, the state voltage at node A drops from +12V to +9V. The processor 44 then determines that the vehicle 12 is connected to the charging station 14 but is not ready to accept energy (State B). Once the processor 44 determines that the vehicle 12 is coupled to the charging station 14, it provides a PWM state voltage command to the state driver 46 to initiate energy transfer from the charging station 14 to the vehicle 12. In an exemplary embodiment, the PWM state voltage command causes the state driver 46 to generate (via oscillator 56) a control pilot voltage signal that oscillates with a duty cycle corresponding to a 16A charge level, the pilot voltage signal being, for example, a square wave of +9V, -12V, 1KHz. The frequency of the oscillating signal is determined by the frequency of the oscillating signal, which ... and the charging station 14, and in response to the correct frequency signal by the vehicle control circuit 20, the switch 28 closes, connecting resistor 24 in parallel with resistor 26. The parallel combination of resistors 24 and 26 acts as a voltage divider as described above. The resulting status voltage is either 6V, indicating that the vehicle 12 is connected and ready to receive energy without ventilation, or 3V, indicating that the vehicle 12 is connected and ready to receive energy with ventilation. As described above, the detection circuit 48 detects the status voltage and the processor 44 can determine a charging state associated with the electric vehicle 12 and close the contactor 51 to enable charging if it determines that the 6V / 3V signal is present (State C).

[0025] Rather than performing a sequence diode test, the processor 44 may determine that only a pilot diode test is required, without any sequence requirement. If the state voltage of node A drops from +12V to +6V when the vehicle 12 is connected to the charging station 14, the processor 44 may determine that only an abbreviated charge is required (i.e., jump from state A to state C, without any sequence requirement). Thus, based on the state voltage of +6V at node A, the processor 44 performs a self-test to check for a proper / compliant electric vehicle 12. Specifically, the processor 44 performs a pilot diode test to cause the state driver circuit 46 to supply −12V to node A. At the same time, the positive voltage branch 52 is turned off to stop supplying +12V to node A. As shown in FIG. 3, the vehicle control circuit 20 includes a diode 22, which blocks the −12V state voltage at node A. Thus, the resistor 24 cannot act as a voltage divider together with the state driver circuit 46 (i.e., the resistor in the state driver circuit). As a result, the -12V state voltage provided by the state driver circuit 46 remains at -12V despite being coupled to the vehicle 12. The processor 44 then receives the -12V detect signal and verifies that the -12V test has passed. Conversely, if the -12V detect signal is not received, the processor 44 recognizes a fault condition. Thus, the pilot diode test performed by the charging device ensures that the proper electric vehicle (including the pilot diode 22) is connected to the charging station 14 and that the pilot diode 22 is functional. Thus, it helps prevent misuse of the charging station 14, such as attempting to charge a device other than the vehicle 12 from the charging station 14. In addition to the -12V detect test, the self-test may include one or more other tests, such as, but not limited to, a ground fault test.

[0026] Thus, as described above, the charging device 38 operates to control the transfer of energy from the power source 36 to the electric vehicle 12 based on a charge cycle state associated with the electric vehicle 12, and the charging device 38 provides a control pilot signal that is used to perform one or more of the functions of verifying that an electric vehicle is present and connected to the charging station 14, allowing the power source 36 to be powered / de-powered, transmitting available supply current to the electric vehicle 12, and monitoring the presence of a ground.

[0027] It is recognized that in typical charging station operation, it is often common for a charging station to use both a pilot diode test and a pilot sequence test before allowing charging of an electric vehicle, but in some cases, it is not necessary to perform both tests to allow charging. That is, the IEC standard specifies that for small electric vehicles under 16A, a "simplified control pilot circuit" should be utilized, and for such vehicles, the sequence test does not need to be performed so that "simplified charging" can be performed instead. Although a charging station can be configured to allow one or both of the sequence test and pilot diode test to be manually / owner-specified disabled, such a configuration can be problematic and / or inefficient. First, if the charging station is a public charging station, many different It is recognized that a variety of vehicles (i.e., both vehicles requiring standard charging and vehicles requiring only abbreviated charging) may utilize the charging station, which may result in frequent manual reconfiguration of the charging station being required or certain vehicles may not be compatible with the currently used test / configuration and therefore be unable to use the charging station. Second, simply disabling both the sequence test and the pilot diode test would allow potential misuse of the charging station 14 (i.e., charging of non-compliant vehicles / devices) which could compromise safety.

[0028] In light of the above, an exemplary embodiment of the charging station 14 includes an automatic test scheme or technique implemented thereby, where the charging station selectively performs a sequence test or a pilot diode test based on the identified requirements and specifications of the electric vehicle requesting charging from the charging station. Referring now to FIG. 4, a technique 60 for such an automatic test scheme or technique is shown. Although the technique 60 is described with reference to the charging station 14, it should be understood that the technique 60 is not limited to the charging station 14 and can be used with other charging station embodiments. In describing the technique 60, refer back to FIG. 3 for reference to the components of the charging station 14, and it will be appreciated that the technique 60 is implemented by the charging device 38 of the charging station 14. The processor 44, the state driver circuitry 46, and the detection circuitry 48 can perform one or more steps related to state voltage generation, detection, charging state identification, and verification to facilitate implementation of the technique 60.

[0029] As shown in FIG. 4 , the technique 60 begins at step 62 in state A where the electric vehicle 12 is not connected to the charging station 14. During this time, the processor 44 provides a high state voltage command (i.e., a “control pilot signal”) to the state driver circuit 46, causing the state driver circuit 46 to provide + / −12V to node A. As long as the +12V control pilot signal is received by the detection circuit 48 (i.e., a +12V detection signal), the processor 44 determines that an electric vehicle or other load is not connected to the charging station 14. In step 64, the electric vehicle 12 is connected to the charging station 14, during which the charging station 14 continues to provide the control pilot voltage signal to the electric vehicle 12 via the state voltage circuit 46. It is recognized that the charging station 14 can determine that the connector 34 is fully inserted into the vehicle receptacle 32 and is properly connected to the electric vehicle 12 by detecting the resistance of the resistor 24, as the resistor 24 causes a drop in the detection signal voltage that is detected by the detection circuit 48. Thus, once the voltage of the control pilot detect signal has decreased, a particular state voltage present at node A resulting from the connection of electric vehicle 12 is determined in step 66. Specifically, whether the resulting state voltage at node A is 6V or 9V is determined, with it being recognized that the voltage present at node A is determined in part based on the configuration of electric vehicle 12 and the vehicle control circuitry 20 included therein. That is, it is recognized that for a small electric vehicle drawing a current less than 16A, switch 28 may be omitted from the vehicle control circuitry 20 (i.e., a simplified control pilot circuit) compared to an electric vehicle 12 drawing a current greater than 16A and including switch 28 as part of the vehicle control circuitry 20. Thus, the control pilot voltage at node A measured / determined in step 66 will vary based on the type of electric vehicle 12 connected to the charging station 14. For a large electric vehicle drawing a current greater than 16A (since switch 28 is open at this stage), 9V will be present at node A, and for a small electric vehicle drawing a current less than 16A, 6V (or 3V for state D charging) will be present at node A (equivalent to a closed switch since switch 28 is not present).This change in voltage at node A is based on whether resistors 24, 26 within the vehicle control circuit 20 are connected in parallel to act as a voltage divider, and the presence of an open switch 28 or the absence of such a switch indicates whether such a parallel connection exists.

[0030] If, at step 66, it is determined that a state voltage of 6V (or 3V) exists at node A, then the technique 60 may proceed to step 70 by identifying that a small electric vehicle drawing less than 16A is connected to the charging station 14, as indicated at 68, and perform a simplified charging to charge the electric vehicle 12. That is, in the simplified charging, a jump from Phase A to Phase C is performed, rather than the typical Phase A to Phase B to Phase C sequence. Based on the determination that the electric vehicle 12 can be charged using the simplified charging technique, it is recognized that a pilot sequence test is not necessary, and thus the technique 60 proceeds to step 72 by performing only a pilot diode test. As previously mentioned, the processor 44 performs the pilot diode test by having the state driver 46 provide −12V to node A via the negative voltage branch 54 (the positive voltage branch 52 is turned off to stop providing +12V to node A while the −12V is provided). Assuming that diode 22 in vehicle control circuit 20 is functioning properly, diode 22 acts to block the −12V state voltage at node A, and resistor 24 cannot operate as a voltage divider with the state driver circuit (i.e., the resistors in the state driver circuit). Thus, the −12V state voltage provided by state driver circuit 46 remains −12V despite being coupled to vehicle 12.

[0031] Thus, upon execution of the pilot diode test at step 72, a determination is made at step 74 as to whether the electric vehicle passed the pilot diode test. If diode 22 acts to block a −12V state voltage at node A, processor 44 then receives a −12V detection signal and confirms that the −12V pilot diode test has passed, as indicated at 76. Thus, technique 60 proceeds to step 78, where state driver 46 functions to oscillate a control pilot signal as an indication that charging station 14 is ready to provide charge to electric vehicle 12. That is, processor 44 causes state driver 46 (i.e., its oscillator 56) to provide a PWM state voltage command to initiate energy transfer from charging station 14 to vehicle 12. In an exemplary embodiment, the PWM state voltage command oscillates at a duty cycle corresponding to a 16A charge level, such as 1 kHz. At step 80, charging station 14 closes contactor 51 of charging device 38 to allow charging station 14 to provide charging power to electric vehicle 12, thus entering state C. In effect, charging station 14 can therefore proceed from state A to state C while performing only the pilot diode test and performing abbreviated charging of the electric vehicle at less than 16 A.

[0032] If, in step 74, the −12V sense signal is not blocked by functional diode 22 at node A, then the −12V sense signal is not received by processor 44 and processor 44 determines that the pilot diode test has not been passed, as indicated at 82. Thus, in step 84 a fault condition is identified and charging of the electric vehicle via charging station 14 is disabled, and thus state F is entered.

[0033] 4 , if it is determined at step 66 that a state voltage of 9V is present at node A, then, as indicated at 86, technique 60 proceeds to step 88 by identifying that a large electric vehicle drawing a current in excess of 16 A is connected to charging station 14, and a normal charging sequence (i.e., not abbreviated charging) is required to charge electric vehicle 12. Based on the determination that a normal charging technique should be employed to charge electric vehicle 12, it is recognized that a typical Phase A→Phase B→Phase C sequence will follow and a sequence test is required. Thus, technique 60 proceeds to step 88 by determining that state driver circuit 46 should provide a control pilot signal accordingly, and at step 88 determines that electric vehicle 12 to be charged is currently in State B (not ready to accept a charge), i.e., Phase C. B1 is recognized. At step 90, as part of the sequence test, processor 44 causes state driver 46 (i.e., its oscillator 56) to oscillate the control pilot signal and provide a PWM state voltage command to initiate energy transfer from charging station 14 to vehicle 12. Charging electric vehicle 12 proceeds to phase B2. In the exemplary embodiment, the PWM state voltage command oscillates at 1 kHz.

[0034] Once the control pilot signal oscillates to initiate energy transfer, vehicle controller 20 closes switch 28 in step 92. Closing switch 28 connects resistor 24 in parallel with resistor 26, indicating that electric vehicle 12 is ready to receive energy from the charging station. That is, when switch 28 is closed, the parallel combination of resistors 24 and 26 acts as a voltage divider as described above, causing the state voltage to drop to 6V, indicating vehicle 12 is plugged in and ready to receive energy without ventilation, or to 3V, indicating vehicle 12 is plugged in and ready to receive energy with ventilation. In step 92, processor 44 checks the control pilot voltage to ensure it is at one of the expected 6V or 3V levels, indicating electric vehicle 12 is ready except for charging power from charging station 14.

[0035] If the check at step 92 indicates that the control pilot voltage is demonstrated to be one of the expected 6V or 3V levels, the technique proceeds to step 80, as indicated at 94, where the charging station 14 closes the contactor 51 of the charging device 38, providing charging power from the charging station 14 to the electric vehicle 12, and state C is entered. Conversely, if the check at step 92 indicates that the control pilot voltage is not one of the expected 6V or 3V levels, as indicated at 96, the technique proceeds to step 84, as indicated at 96, where the processor 44 determines that a fault condition exists in the charging station 14 and / or the electric vehicle. Thus, a fault condition is declared at step 84, and charging of the electric vehicle 12 via the charging station 14 is disabled, and state F is thus entered.

[0036] 4, again returning to step 66, if step 66 determines that neither a 6V nor a 9V state voltage is present at node A, then technique 60 proceeds directly to step 84, as indicated at 98, where processor 44 determines that a fault condition exists in charging station 14 and / or the electric vehicle. Thus, a fault condition is declared in step 84 and charging of electric vehicle 12 via charging station 14 is disabled, thus entering state F.

[0037] Advantageously, embodiments of the present invention provide an electric vehicle charging station and method of operation that prevents misuse of the electric vehicle charging station in providing charging power to electric vehicles. An automated pre-charge test procedure performed by the charging station provides flexible charging authorization to accommodate various types of electric vehicles while meeting desired safety and efficiency criteria, as well as providing AC or DC charging. The charging station performs an automated check of the electric vehicle requesting charging and, based on the check, determines an appropriate pre-charge test procedure to authorize / enable charging of the electric vehicle.

[0038] A technical effect of the methods, systems, and apparatus described herein is that a computer-implemented technique is provided that includes identifying parameters of an electric vehicle connected to a charging station and requesting charging therefrom, automatically determining an appropriate pre-charge test procedure to permit / enable charging of the electric vehicle based on the identified parameters, and ensuring compliance with the selected pre-charge test procedure to allow charging of the electric vehicle to proceed.

[0039] Therefore, according to one embodiment of the present invention, one or more energy storage devices and a power A charging station for charging an electric vehicle is provided, the charging station including a power source operable to provide recharging power to one or more energy storage devices of the electric vehicle and a charging device configured to control energy transfer from the power source to the electric vehicle. The charging device is configured to provide to the vehicle control circuit of the electric vehicle a control pilot signal that is received by the vehicle control circuit upon connection of the electric vehicle to the charging station. The charging device is also configured to measure a voltage level of the control pilot signal upon connection of the electric vehicle to the charging station, execute a selected pre-charge test routine based on the measured voltage level of the control pilot signal, and enable charging of the electric vehicle from the power source upon compliance with the executed selected pre-charge test routine.

[0040] According to another embodiment of the invention, a method of pre-charge testing for authorizing use of an electric vehicle charging station is performed by a charging device of an electric vehicle charging station. The method includes the steps of: upon detecting connection of a load to the electric vehicle charging station, providing a control pilot signal to the load; and determining a state of the load charging cycle based on the control pilot signal, the load charging cycle including at least state A, state B, and state C, each defined by a different control pilot signal voltage level. The method also includes the steps of performing a pilot sequence test if the charging cycle progresses from state A to state B upon connection of the load to the electric vehicle charging station; performing a pilot diode test if the charging cycle progresses from state A to state C upon connection of the load to the electric vehicle charging station; and enabling charging of the load from the electric vehicle charging station upon completion and compliance of one of the performed pilot sequence tests or pilot diode tests.

[0041] According to yet another embodiment of the present invention, a charging station for charging an electric vehicle is provided, the charging station including a state driver circuit configured to generate and provide a control pilot signal to a vehicle control circuit of the electric vehicle, a detection circuit configured to measure a voltage level of the control pilot signal responsive to providing the control pilot signal to the vehicle control circuit, and a processor, the processor being programmed to: determine a state of charge associated with the electric vehicle based on the measured voltage level of the control pilot signal, execute a first pre-charge test routine if the voltage level of the control pilot signal is a first voltage level, execute a second pre-charge test routine if the voltage level of the control pilot signal is a second voltage level, and enable charging of the electric vehicle from the charging station upon completion and compliance of one of the executed first pre-charge test routine or the second pre-charge test routine.

[0042] This specification uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems, and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims. [Embodiment 1] 1. A charging station (14) for charging an electric vehicle (12) including one or more energy storage devices (16) and a vehicle control circuit (20) having a pilot diode (22), a power source (36) operable to provide recharging power to the one or more energy storage devices (16) of the electric vehicle (12); configured to control the transfer of energy from the power source to the electric vehicle. and a charging device (38) connected to the charging circuit, the charging device (38) comprising: providing a vehicle control circuit (20) of the electric vehicle (12) with a control pilot signal that is received by the vehicle control circuit (20) upon connection of the electric vehicle (12) to the charging station (14); measuring a voltage level of the control pilot signal when the electric vehicle (12) is connected to the charging station (14); performing a selected precharge test routine based on the measured voltage level of the control pilot signal; and enabling charging of the electric vehicle (12) from the power source (36) upon compliance with the selected pre-charge test routine being executed. The charging station (14) is configured to [Embodiment 2] The charging device (38) determining a state of charge associated with the electric vehicle (12) based on the measured voltage level of the control pilot signal; performing a first pre-charge test routine if the voltage level of the control pilot signal is a first voltage level, and performing a second pre-charge test routine if the voltage level of the control pilot signal is a second voltage level; Upon completion and compliance with one of the executed first pre-charge test routine or the second pre-charge test routine, enabling charging of the electric vehicle (12) from the power source (36). 2. The charging station (14) of claim 1, further configured as follows: [Embodiment 3] 3. A charging station (14) as described in embodiment 2, wherein the first voltage level is approximately 9 V, and the voltage level of approximately 9 V of the control pilot signal indicates that a switch (28) is present in the vehicle control circuit (20) and is open. [Embodiment 4] A charging station (14) as described in embodiment 3, wherein the first pre-charge test routine includes a pilot sequence test that follows a sequence of state A → state B → state C, and the voltage level of the control pilot signal changes between each state. [Embodiment 5] When performing the pilot sequence test, the charging device (38) oscillating the control pilot signal provided to the vehicle control circuit (20), such that the oscillating control pilot signal closes the switch (28) within the vehicle control circuit (20); measuring the voltage level of the control pilot signal when the switch (28) in the vehicle control circuit (20) is closed; closing a contactor (51) in the charging device (38) to enable charging of the electric vehicle (12) from the power source (36) when the voltage level of the control pilot signal is a third level; If not, declare a fault condition and disable charging of the electric vehicle (12) from the power source (36). A charging station (14) as described in embodiment 4, configured as follows. [Embodiment 6] 6. A charging station (14) as described in embodiment 5, wherein the third voltage level is either about 3V or about 6V. [Embodiment 7] The charging state of claim 2, wherein the second voltage level is about 3V or about 6V, and the voltage level of about 3V or 6V of the control pilot signal indicates that the vehicle control circuit (20) includes a simplified vehicle control circuit (20) that does not have a switch (28). tion (14). [Embodiment 8] A charging station (14) as described in embodiment 7, wherein the second pre-charge test routine includes a pilot diode (22) test following a sequence from state A to state C, and the voltage level of the control pilot signal changes between each state. [Embodiment 9] When performing the pilot diode (22) test, the charging device (38) providing a control pilot signal having a voltage of -12V to the vehicle control circuit (20); measuring the voltage level of the control pilot signal in response to the providing of the control pilot signal to the vehicle control circuit (20); if the voltage level of the control pilot signal remains at approximately -12V, then oscillating the control pilot signal provided to the vehicle control circuit (20) to close a contactor (51) in the charging device (38); If not, declare a fault condition and disable charging of the electric vehicle (12) from the power source (36). A charging station (14) as described in embodiment 8, configured as follows. [Embodiment 10] 10. The charging station of claim 9, wherein the charging device is configured to oscillate the control pilot signal at a duty cycle corresponding to a 16A charging level. [Embodiment 11] 3. The charging station (14) of claim 2, wherein the charging device (38) is configured to declare a fault condition and disable charging of the electric vehicle (12) from the power source (36) if the voltage level of the control pilot signal is not either the first voltage level or the second voltage level when the electric vehicle (12) is connected to the charging station (14). [Embodiment 12] The charging device (38) a state driver circuit (46) configured to generate the control pilot signal; a detection circuit (48) configured to measure the voltage level of the control pilot signal responsive to the provision of the control pilot signal to the vehicle control circuit (20); a processor (44) programmed to control generation of the control pilot signal and provide commands to the state driver (46) to enable and disable charging of the electric vehicle (12) from the power source (36); 2. The charging station (14) of embodiment 1, comprising: [Embodiment 13] 1. A method of pre-charge testing for authorizing use of an electric vehicle charging station (14), the method being performed by a charging device (38) of the electric vehicle charging station (14), comprising: upon detecting a connection of a load to the electric vehicle charging station (14), providing a control pilot signal to the load; determining a state of a load charging cycle based on the control pilot signal, the load charging cycle including at least state A, state B, and state C, each defined by a different control pilot signal voltage level; performing a pilot sequence test if the charging cycle progresses from state A to state B upon connection of the load to the electric vehicle charging station (14); performing a pilot diode (22) test if the charging cycle progresses from state A to state C upon connection of the load to the electric vehicle charging station (14); The pilot sequence test or the pilot diode (22) test performed enabling charging of the load from the electric vehicle charging station (14) upon completion and compliance of one of the tests; The method includes: [Embodiment 14] 14. The method of claim 13, wherein the charge cycle is in state B when the control pilot signal voltage level is approximately 9V, the 9V control pilot signal voltage level indicating that the load includes a vehicle control circuit (20) including a switch (28) in an open state to charge the load at a charge level of 16A or greater. [Embodiment 15] The step of performing a pilot sequence test includes: oscillating the control pilot signal provided to a vehicle control circuit (20), the oscillating control pilot signal causing the switch (28) to close; measuring the control pilot signal voltage level when the vehicle control circuit switch (28) is closed; if the measured control pilot signal voltage level is approximately 6 volts when the vehicle control circuit switch (28) is closed, causing a contactor (51) in the electric vehicle charging station (14) to close to enable charging of the load; otherwise, declaring a fault condition and disabling charging of the load via the electric vehicle charging station (14); 15. The method of embodiment 14, comprising: [Embodiment 16] 14. The method of claim 13, wherein the charging cycle is in state C when the control pilot signal voltage level is about 6V. [Embodiment 17] the 6V control pilot signal voltage level indicates that the load includes a simplified vehicle control circuit (20) without a switch (28) when the load charging cycle jumps from state A to state C, thereby providing charging of the load at a charge level of 16A or greater; 17. The method of claim 16, wherein the 6V control pilot signal voltage level indicates that the load includes a vehicle control circuit (20) that includes a switch (28) that is closed when the load charging cycle goes from state B to state C, thereby providing charging of the load at a charge level of 16 A or greater. [Embodiment 18] The step of performing a pilot diode (22) test includes: providing a control pilot signal having a voltage of −12V to the load; measuring the control pilot signal voltage level in response to the providing of the -12V control pilot signal; if the voltage level of the control pilot signal remains at approximately -12V, oscillating the control pilot signal to close a contactor (51) in the electric vehicle charging station (14); otherwise, declaring a fault condition and disabling charging of the load via the electric vehicle charging station (14); 17. The method of embodiment 16, comprising: [Embodiment 19] 19. The method of claim 18, wherein the control pilot signal oscillates with a duty cycle corresponding to a 16 A charge level as part of the pilot diode (22) test when the charge cycle jumps from state A to state C. [Embodiment 20] A charging station (14) for charging an electric vehicle (12), comprising: A control pilot signal is generated and supplied to a vehicle control circuit (20) of the electric vehicle (12). A state driver circuit (46) configured to: a detection circuit (48) configured to measure a voltage level of the control pilot signal in response to the providing of the control pilot signal to the vehicle control circuit (20); a processor (44) comprising: determining a state of charge associated with the electric vehicle (12) based on the measured voltage level of the control pilot signal; performing a first pre-charge test routine if the voltage level of the control pilot signal is a first voltage level, and performing a second pre-charge test routine if the voltage level of the control pilot signal is a second voltage level; and a charging station (14) programmed to enable charging of the electric vehicle (12) from the charging station (14) upon completion of and compliance with one of the executed first pre-charge test routine or the second pre-charge test routine. [Explanation of symbols]

[0043] 10. System 12 Electric cars and electric vehicles 14 Vehicle Charging Stations 16 Energy storage device 18 Motor 20 Vehicle control circuit, vehicle controller 22 Pilot diode, functional diode 24 resistor 26 resistor 28 Switching Devices, Switches 30 Charging conduit 32 Charging receptacle, vehicle receptacle 34 Connector 36 Power supply 38 Charging device 44 processors 46 State drive circuit, state voltage circuit 48 Detection Circuit 50 Memory 51 Contactor 52 Positive voltage branch 54 Negative voltage branch 56 Oscillator 60 Technology

Claims

1. A charging station for charging an electric vehicle, comprising: a state driver circuit configured to generate a control pilot signal when the electric vehicle is connected to a charging station and to provide the control pilot signal to a vehicle control circuit of the electric vehicle; a detection circuit configured to measure a voltage level of the control pilot signal in response to providing the control pilot signal to the vehicle control circuit; When the electric vehicle is connected to the charging station, determining a state of charge associated with the electric vehicle based on the measured voltage level of the control pilot signal; performing a first precharge test routine selected from either a pilot sequence test or a pilot diode test when the voltage level of the control pilot signal is a first voltage level, or performing a second precharge test routine selected from either a pilot sequence test or a pilot diode test when the voltage level of the control pilot signal is a second voltage level different from the first voltage level; enabling charging of the electric vehicle from the charging station upon completion and compliance with one of the executed first pre-charge test routine or the second pre-charge test routine. a processor programmed to A charging station equipped with

2. 2. The charging station of claim 1, wherein the first voltage level is approximately 9V, and wherein the approximately 9V voltage level of the control pilot signal indicates that a switch is present and open in the vehicle control circuit.

3. 2. The charging station of claim 1, wherein the second voltage level is approximately 3V or approximately 6V, and the approximately 3V or 6V voltage level of the control pilot signal indicates that the vehicle control circuit includes a simplified vehicle control circuit that does not have a switch.

4. A charging station as described in claim 1, wherein a charging device included in the charging station is configured to oscillate the control pilot signal with a duty cycle corresponding to a 16A charging level.

5. The charging station of claim 1, wherein a charging device included in the charging station is configured to declare a fault condition and disable charging of the electric vehicle from a power source if the voltage level of the control pilot signal is neither the first voltage level nor the second voltage level when the electric vehicle is connected to the charging station.

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