ELECTRIC CHARGING SYSTEM AND METHOD

Abstract

A method for operating an electric vehicle charging station may include measuring the unloaded insulation resistance of the charging station with no load devices connected. The method may further include measuring the loaded insulation resistance of the charging station with two or more load devices connected to it. The two or more load devices are in electrical communication with each other via the charging station. The method may also include modifying the operation of the charging station, at least partially, based on the unloaded insulation resistance and / or the loaded insulation resistance.

Description

INTRODUCTION

[0001] The present disclosure relates to systems and methods for charging electrical devices such as electric vehicles.

[0002] Electric vehicle charging systems (EVSEs) are designed to charge portable devices powered by rechargeable energy storage systems (RESSs). A prominent example of such a system is electric vehicle servicing equipment (EVSE), which includes both an alternating current (AC) EVSE and a direct current (DC) EVSE for charging electric vehicles. An AC EVSE allows for a direct connection to the grid, with the necessary AC / DC conversion handled by the vehicle itself. A DC EVSE delivers direct current to the vehicle, eliminating the need for on-board conversion. Both AC and DC EVSE systems must maintain continuous isolation between low-voltage and high-voltage buses, as well as ground buses. Galvanic isolation can be used to maintain this isolation.For example, galvanically isolated transformers can be used to transfer energy in EVSE power converters to provide continuous isolation between low and high voltage buses as well as ground buses.

[0003] While current electric charging systems and methods achieve their intended purpose, there is a need for a new and improved system and method for charging electrical devices and vehicles without galvanic isolation. SUMMARY

[0004] A method for operating an electric vehicle charging station is provided according to several aspects. The method may include measuring the unloaded insulation resistance of the charging station with no load devices connected. The method may further include measuring the loaded insulation resistance of the charging station with two or more load devices connected to it. These two or more load devices are in electrical communication with each other via the charging station. The method may also include modifying the operation of the charging station, at least partially, based on the unloaded insulation resistance and / or the loaded insulation resistance.

[0005] In another aspect of the present disclosure, measuring the unloaded insulation resistance can further comprise measuring the unloaded insulation resistance of the electric vehicle charging station. The electric vehicle charging station includes a power source and several uninsulated converters for connecting each of the two or more load devices to the power source. The unloaded insulation resistance comprises an unloaded positive insulation resistance and an unloaded negative insulation resistance.

[0006] In a further aspect of the present disclosure, measuring the loaded insulation resistance can also include measuring a first loaded insulation resistance, wherein a first load device is connected to a first non-insulating converter of the electric vehicle charging station. Measuring the loaded insulation resistance can further comprise measuring a second loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric vehicle charging station and a second load device is connected to a second non-insulating converter of the electric vehicle charging station.

[0007] In another aspect of the present disclosure, changing the operation of the electric vehicle charging station may further include determining the insulation resistance of the first load device, at least partially, based on the unloaded insulation resistance and the first loaded insulation resistance. Changing the operation of the electric vehicle charging station may further include determining the insulation resistance of the second load device, at least partially, based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance. Changing the operation of the electric vehicle charging station may further include changing the operation of the electric vehicle charging station, at least partially, based on the insulation resistance of the first load device and / or the insulation resistance of the second load device.

[0008] In another aspect of the present disclosure, measuring the loaded insulation resistance can further comprise measuring the first loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric vehicle charging station. The first loaded insulation resistance comprises a first loaded positive insulation resistance and a first loaded negative insulation resistance. Measuring the loaded insulation resistance can further comprise measuring the second loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric vehicle charging station and the second load device is connected to the second non-insulating converter of the electric vehicle charging station. The second loaded insulation resistance comprises a second loaded positive insulation resistance and a second loaded negative insulation resistance.

[0009] In another aspect of the present disclosure, modifying the operation of the electric vehicle charging station may further include determining the insulation resistance of the first load device, at least partially, based on the unloaded insulation resistance and the first loaded insulation resistance. The insulation resistance of the first load device comprises a positive insulation resistance and a negative insulation resistance. Modifying the operation of the electric vehicle charging station may further include determining the insulation resistance of the second load device, at least partially, based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance.The insulation resistance of the second load device comprises a positive insulation resistance and a negative insulation resistance. Furthermore, modifying the operation of the electric vehicle charging station may involve modifying its operation, at least partially, based on the positive insulation resistance of the first load device and / or the negative insulation resistance of the first load device and / or the positive insulation resistance of the second load device and / or the negative insulation resistance of the second load device.

[0010] In another aspect of the present disclosure, determining the insulation resistance of the first load device may further comprise determining the positive insulation resistance of the first load device using the following equation: RI,L,1+=[VSVL,1∗[1RI,S,1+−1RI,S,e,+]]−1 where RI,L,1+ The positive insulation resistance of the first load device is V S a high voltage of the electric charging station is, v L,1 a voltage of the first load device is RI,S,1+ the first loaded positive insulation resistance is and RI,S,e,+ The unloaded positive insulation resistance is the determining factor. Determining the insulation resistance of the first load device may further include determining the negative insulation resistance of the first load device using the following equation: RI,L,1−[1RI,S,1−−1RI,S,e,−−[1−VL,1VS∗1RI,L,1−]]−1 where RI,L,1− the negative insulation resistance of the first load device is, RI,S,1− the first loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,1 the voltage of the first load device is, VS the high voltage of the electric charging station is and RI,L,1+ The positive insulation resistance of the first load device is [value missing].

[0011] In another aspect of the present disclosure, determining the insulation resistance of the second load device may further comprise determining the positive insulation resistance of the second load device using the following equation: RI,L,2+=[VSVL,2∗[1RI,S,2+−1RI,S,1+]]−1 where RI,L,2+ The positive insulation resistance of the second load device is V S a high voltage of the electric charging station is, V L,2 a voltage of the second load device is RI,S,2+ the second loaded positive insulation resistance is and RI,S,1+ The first loaded positive insulation resistance is determined. Determining the insulation resistance of the second load device may further involve determining the negative insulation resistance of the second load device using the following equation: RI,L,2−=[1RI,S,2−−1RI,S,e−−[1−VL,2VS∗1RI,L,2+]]−1 where RI,L,2− the negative insulation resistance of the second load device is, RI,S,2− the second loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,2 The voltage of the second load device is V s the high voltage of the electric charging station is and RI,L,2+ The positive insulation resistance of the second load device is [value missing].

[0012] In another aspect of the present disclosure, changing the operation of the electric vehicle charging station may further include comparing the second loaded insulation resistance with a predetermined insulation resistance threshold. Changing the operation of the electric vehicle charging station may also include disconnecting the first load device and / or the second load device from the electric vehicle charging station in response to a determination that the second loaded insulation resistance is less than the predetermined insulation resistance threshold, at least partially based on the positive insulation resistance of the first load device and / or the negative insulation resistance of the first load device and / or the positive insulation resistance of the second load device and / or the negative insulation resistance of the second load device.

[0013] In another aspect of the present disclosure, disconnecting the first load device and / or the second load device may further comprise disconnecting the first load device in response to a determination that the positive insulation resistance of the first load device is less than the positive insulation resistance of the second load device, or that the negative insulation resistance of the first load device is less than the negative insulation resistance of the second load device. Disconnecting the first load device and / or the second load device may further comprise disconnecting the second load device in response to a determination that the positive insulation resistance of the second load device is less than the positive insulation resistance of the first load device, or that the negative insulation resistance of the second load device is less than the negative insulation resistance of the first load device.

[0014] An electric vehicle charging station is provided for charging multiple electric vehicles, according to several aspects. The charging station may include a power system, which may contain a power source. The charging station may also include multiple non-isolating converters in electrical communication with the power source. Furthermore, the charging station may include multiple charging handles, each of which is electrically connected to one of the multiple non-isolating converters via one of several contactors, and each of which serves to connect to one of the multiple electric vehicles. The charging station may also include a control system, which may contain the multiple contactors for controlling the connection between the multiple non-isolating converters and the multiple charging handles.The electric vehicle charging station may further include an insulation monitoring device (IMD) in electrical communication with the power system to monitor the insulation resistance of the power system. The electric vehicle charging station may also include a controller in electrical communication with the multiple contactors and the IMD. The controller is programmed to measure the unloaded insulation resistance of the electric vehicle charging station using the IMD, with none of the multiple electric vehicles connected. The unloaded insulation resistance includes an unloaded positive insulation resistance and an unloaded negative insulation resistance. The controller is further programmed to measure the loaded insulation resistance of the electric vehicle charging station with two or more of the multiple electric vehicles connected to the electric vehicle charging station.The controller is further programmed to modify the operation of one or more of the multiple contactors, at least partially, based on the unloaded insulation resistance and / or the loaded insulation resistance.

[0015] In another aspect of the present disclosure, in order to measure the loaded insulation resistance, the controller is further programmed to measure a first loaded insulation resistance, wherein a first vehicle of the multiple electric vehicles is connected to a first non-insulating converter of the multiple non-insulating converters. The first loaded insulation resistance comprises a first loaded positive insulation resistance and a first loaded negative insulation resistance. To measure the loaded insulation resistance, the controller is further programmed to measure a second loaded insulation resistance, wherein the first vehicle of the multiple electric vehicles is connected to the first non-insulating converter of the multiple non-insulating converters, and a second vehicle of the multiple electric vehicles is connected to a second non-insulating converter of the multiple non-insulating converters.The second loaded insulation resistance comprises a second loaded positive insulation resistance and a second loaded negative insulation resistance.

[0016] In another aspect of the present disclosure, the controller is further programmed to determine a first vehicle insulation resistance of the first vehicle, at least partially, based on the unloaded insulation resistance and the first loaded insulation resistance, in order to change the operation of one or more of the multiple contactors. The first vehicle insulation resistance comprises a positive insulation resistance of the first vehicle and a negative insulation resistance of the first vehicle. To change the operation of one or more of the multiple contactors, the controller is further programmed to determine a second vehicle insulation resistance of the second vehicle, at least partially, based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance.The second vehicle insulation resistance comprises a positive insulation resistance of the second vehicle and a negative insulation resistance of the second vehicle. To modify the operation of one or more of the multiple contactors, the controller is further programmed to modify the operation of one or more of the multiple contactors, at least partially, based on the positive insulation resistance of the first vehicle and / or the negative insulation resistance of the first vehicle and / or the positive insulation resistance of the second vehicle and / or the negative insulation resistance of the second vehicle.

[0017] In another aspect of the present disclosure, the controller is further programmed to determine the positive insulation resistance of the first vehicle using the following equation: RI,L,1+=[VSVL,1∗[1RI,S,1+−1RI,S,e,+]]−1 where RI,L,1+ The positive insulation resistance of the first load device is V S a high voltage of the electric charging station is, v L,1 a voltage of the first load device is RI,S,1+ the first loaded positive insulation resistance is and RI,S,e,+ The unloaded positive insulation resistance is given. To determine the first vehicle insulation resistance, the controller is further programmed to determine the negative insulation resistance of the first vehicle using the following equation: RI,L,1−[1RI,S,1−−1RI,S,e,−−[1−VL,1VS∗1RI,L,1+]]−1 where RI,L,1− the negative insulation resistance of the first load device is, RI,S,1− the first loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,1the voltage of the first load device is, V S the high voltage of the electric charging station is and RI,L,1+ The positive insulation resistance of the first load device is [value missing].

[0018] In another aspect of the present disclosure, the controller is further programmed to determine the positive insulation resistance of the second vehicle using the following equation: RI,L,2+=[VSVL,2∗[1RI,S,2+−1RI,S,1+]]−1 where RI,L,2+ The positive insulation resistance of the second load device is V S a high voltage of the electric charging station is, V L,2 a voltage of the second load device is RI,S,2+ the second loaded positive insulation resistance is and RI,S,1+ The first loaded positive insulation resistance is determined. To determine the second vehicle's insulation resistance, the controller is further programmed to determine the negative insulation resistance of the second vehicle using the following equation: RI,L,2−=[1RI,S,2−−1RI,S,e−−[1−VL,2VS∗1RI,L,2+]]−1 where RI,L,2− the negative insulation resistance of the second load device is, RI,S,2− the second loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,2 The voltage of the second load device is V s the high voltage of the electric charging station is and RI,L,2+ The positive insulation resistance of the second load device is [value missing].

[0019] In another aspect of the present disclosure, to change the operation of one or more of the multiple contactors, the controller is further programmed to compare the second loaded insulation resistance with a predetermined insulation resistance threshold. To change the operation of one or more of the multiple contactors, the controller is further programmed to disconnect the first vehicle and / or the second vehicle from the electric charging station using one or more of the multiple contactors in response to a determination that the second loaded insulation resistance is less than the predetermined insulation resistance threshold.

[0020] In another aspect of the present disclosure, the controller for disconnecting the first vehicle and / or the second vehicle is further programmed to disconnect the first vehicle using one or more of the multiple contactors in response to a determination that the positive insulation resistance of the first vehicle is less than the positive insulation resistance of the second vehicle or that the negative insulation resistance of the first vehicle is less than the negative insulation resistance of the second vehicle.To separate the first vehicle and / or the second vehicle, the controller is further programmed to separate the second vehicle using one or more of the multiple contactors in response to a determination that the positive insulation resistance of the second vehicle is less than the positive insulation resistance of the first vehicle or that the negative insulation resistance of the second vehicle is less than the negative insulation resistance of the first vehicle.

[0021] A method for operating an electric vehicle charging station for charging multiple electric vehicles is provided according to several aspects. The method may include measuring the unloaded insulation resistance of the charging station when none of the multiple electric vehicles are connected. The charging station contains a power source and several non-insulated converters for connecting each of the multiple electric vehicles to the power source. The unloaded insulation resistance comprises an unloaded positive insulation resistance and an unloaded negative insulation resistance. The method may further include measuring the loaded insulation resistance of the charging station when two or more of the multiple electric vehicles are connected to the charging station. The two or more of the multiple electric vehicles are in electrical communication with each other via the charging station.The procedure may also include disconnecting one or more of the multiple electric vehicles from the electric charging station, at least partially, based on the unloaded insulation resistance and / or the loaded insulation resistance.

[0022] In another aspect of the present disclosure, measuring the loaded insulation resistance can further comprise measuring a first loaded insulation resistance, wherein a first vehicle of the multiple electric vehicles is connected to a first non-insulating converter of the multiple non-insulated converters. The first loaded insulation resistance comprises a first loaded positive insulation resistance and a first loaded negative insulation resistance. Measuring the loaded insulation resistance can further comprise measuring a second loaded insulation resistance, wherein the first vehicle is connected to the first non-insulating converter of the electric vehicle charging station and a second vehicle of the multiple electric vehicles is connected to a second non-insulating converter of the multiple non-insulated converters.The second loaded insulation resistance comprises a second loaded positive insulation resistance and a second loaded negative insulation resistance.

[0023] In another aspect of the present disclosure, disconnecting one or more of the multiple electric vehicles from the charging station may further include determining a first vehicle insulation resistance, at least partially, based on the unloaded insulation resistance and the first loaded insulation resistance. The first vehicle insulation resistance comprises a positive insulation resistance of the first vehicle and a negative insulation resistance of the first vehicle. Disconnecting one or more of the multiple electric vehicles from the charging station may further include determining a second vehicle insulation resistance, at least partially, based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance.The second vehicle insulation resistance comprises a positive insulation resistance and a negative insulation resistance of the second vehicle. Disconnecting one or more of the multiple electric vehicles from the electric charging station may further include disconnecting the first vehicle in response to a determination that the positive insulation resistance of the first vehicle is less than the positive insulation resistance of the second vehicle, or that the negative insulation resistance of the first vehicle is less than the negative insulation resistance of the second vehicle.Disconnecting one or more of the multiple electric vehicles from the electric charging station may also include disconnecting the second vehicle in response to a determination that the positive insulation resistance of the second vehicle is less than the positive insulation resistance of the first vehicle or that the negative insulation resistance of the second vehicle is less than the negative insulation resistance of the first vehicle.

[0024] Further areas of application will become apparent from the description provided here. It should be understood that the description and specific examples serve only for illustration and are not intended to limit the scope of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described here serve only for illustration and are not intended to limit the scope of the present disclosure in any way; they show: Fig. 1 a schematic diagram of an electric vehicle charging station according to an exemplary embodiment and Fig. 2 a flowchart of a procedure for operating the electric charging station according to an exemplary embodiment. DETAILED DESCRIPTION

[0026] The following description is merely exemplary and is not intended to limit the present disclosure, application or uses.

[0027] To ensure the proper operation of electric vehicle charging systems, the isolation between both low-voltage and high-voltage buses, as well as the ground bus, must be continuously monitored and maintained. Electric vehicle charging systems can be designed with galvanic isolation to ensure proper isolation. However, galvanic isolation can increase the resource usage, weight, and losses of electric vehicle charging systems. Therefore, the present disclosure provides a new and improved system and method for charging electronic devices, including, for example, electric vehicles, without galvanic isolation.

[0028] With reference to Fig. Reference numeral 10 illustrates and generally specifies an electric vehicle charging station. The electric vehicle charging station 10 generally includes a power system and a control system. The power system generally includes a power source 12, several non-isolating converters 14, and several charging handles 16. The control system generally includes several contactors 18, an insulation monitoring device (IMD) 20, and a controller 22. The electric vehicle charging station 10 is used to charge several electric vehicles 24.

[0029] The power source 12 is a source of electrical power used to charge the multiple electric vehicles 24. In a non-restrictive example, the power source 12 includes a grid connection to an alternating current (AC) grid, a rectifier, and one or more direct current (DC) power converters and / or filters. In another non-restrictive example, the power source 12 includes a generator (e.g., an internal combustion engine generator) for generating AC power, a rectifier, and one or more DC power converters and / or filters. In yet another non-restrictive example, the power source 12 includes a renewable energy source (e.g., solar panels and / or wind turbines) for generating AC or DC power and one or more DC power converters and / or filters and / or rectifiers.In another non-restrictive example, the power source 12 includes a fuel cell energy source (e.g., a hydrogen fuel cell) for generating DC power and one or more DC power converters and / or filters. In another non-restrictive example, the power source 12 further includes a rechargeable energy storage system (RESS) (e.g., one or more rechargeable batteries and an associated circuit arrangement) for buffering and storing energy.

[0030] In an exemplary embodiment, the power source 12 is configured to provide high-voltage direct current (HVDC) power to the multiple non-isolating converters 14. Accordingly, the power source 12 includes a positive high-voltage bus 26a and a negative high-voltage bus 26b, which are connected to the multiple non-isolating converters 14. Furthermore, the power source 12 is connected to a common ground bus 28, which provides a path for current flow in the event of a fault. In a non-restrictive example, the common ground bus 28 is tied to the AC power supply and / or connected to ground. The common ground bus 28 is also connected to the multiple non-isolating converters 14 and the multiple charging handles 16, as discussed in more detail below.

[0031] The multiple non-isolating converters 14 are used to step down the high voltage provided by the power source 12 to suitable voltages for charging the multiple electric vehicles 24 and / or to regulate current flow from the power source 12 to / from the multiple charging handles 16. In an exemplary embodiment, the multiple non-isolating converters 14 include one or more DC step-down converters, DC step-down / step-up converters, and / or the like. A high-voltage side of each of the multiple non-isolating converters 14 is connected to the positive high-voltage bus 26a and the negative high-voltage bus 26b of the power source 12. A low-voltage side of each of the multiple non-isolating converters 14 is connected to the multiple contactors 18.

[0032] Within the scope of this disclosure, "non-isolating" means a converter wherein the high-voltage side is not galvanically isolated from the low-voltage side. In other words, during normal operation of the converter, an electrical connection exists between components on the high-voltage and low-voltage sides. The use of non-isolating converters can provide advantages, for example, in electrical efficiency, equipment utilization, and weight savings. It is understood that any non-galvanically isolated unidirectional or bidirectional DC or AC / DC converters capable of voltage and / or current control are within the scope of this disclosure. In the exemplary embodiment described in Fig. As shown in Figure 1 and discussed below, the multiple non-isolating converters 14 include a first non-isolating converter 14a and a second non-isolating converter 14b. It is to be understood that the multiple non-isolating converters 14 can contain any number of converters without deviating from the scope of this disclosure.

[0033] The multiple charging handles 16 are used to connect the multiple electric vehicles 24 to the electric charging station 10. In one exemplary embodiment, the multiple charging handles 16 include electrical connectors for connecting the multiple contactors 18 and the common ground bus 28 to the multiple electric vehicles 24. In a non-limiting example, the multiple charging handles 16 include additional electrical connectors for communication between the multiple electric vehicles 24 and the electric charging station 10 (e.g., a control status connector, a control feedforward connector, and / or the like). In a non-limiting example, the multiple charging handles 16 are implemented according to patent applications such as SAE J1772, SAE J3400, and / or the like. It is understood that any electrical connector used for transmitting energy to charge a load device, such as a charging station 10, is included.which is suitable for several electric vehicles 24, within the scope of the present disclosure.

[0034] In the exemplary embodiment shown in Fig. As shown in Figure 1 and discussed below, the multiple charging handles 16 include a first charging handle 16a for connection to a first vehicle 24a of the multiple electric vehicles 24 and a second charging handle 16b for connection to a second vehicle 24b of the multiple electric vehicles 24. In a non-restrictive example, when the first charging handle 16a is plugged into the first vehicle 24a, the low-voltage side of the first non-insulating converter 14a is connected to a traction battery (not shown) of the first vehicle 24a by means of two of the multiple contactors 18, and the common ground bus 28 is connected to a chassis ground of the first vehicle 24a.

[0035] When the second charging handle 16b is plugged into the second vehicle 24b, the low-voltage side of the second non-insulating converter 14b is connected to a traction battery (not shown) of the second vehicle 24b by means of two of the multiple contactors 18, and the common ground bus 28 is connected to a chassis ground of the second vehicle 24b. It is understood that the power system can include any number of charging handles 16 for connection to any number of vehicles without deviating from the scope of this disclosure.

[0036] The multiple contactors 18 are used to connect / disconnect the multiple non-insulating converters 14 to the multiple charging handles 16 (and thus to the multiple electric vehicles 24 and / or other connected load device). In an exemplary embodiment, each of the multiple contactors 18 is an electromechanical device designed to make or break electrical connections in circuits carrying high voltages and / or currents. In a non-limiting example, each of the multiple contactors 18 includes a set of contacts (not shown), an electromagnet (not shown), and a control circuit (not shown). The set of contacts includes movable and fixed contact points that can be brought together or separated by the electromagnet. The electromagnet generates a magnetic field when switched on by the control circuit.The magnetic field attracts or repels the movable contact points, thereby actuating each of the multiple contactors 18.

[0037] During operation, when the controller 22 sends a signal to the control circuit, the control circuit switches on the electromagnet and the contacts close, allowing an electric current to flow between the multiple non-isolating converters 14 and the multiple charging handles 16. Conversely, when the control circuit switches off the electromagnet, the contacts open, interrupting the current flow between the multiple non-isolating converters 14 and the multiple charging handles 16.

[0038] In the exemplary embodiment shown in Fig. As shown in Figure 1 and discussed below, the multiple contactors 18 comprise a first contactor 18a, a second contactor 18b, a third contactor 18c, and a fourth contactor 18d. It is understood that the multiple contactors 18 can be implemented using any electronically controllable switch, including relays, solid-state electronic switches (e.g., transistors), and / or the like, without deviating from the scope of this disclosure. The multiple contactors 18 are in electrical communication with the controller 22, as discussed in more detail below.

[0039] The IMD 20 is used to determine a positive insulation resistance between the positive high-voltage bus 26a and the common ground bus 28, and a negative insulation resistance between the negative high-voltage bus 26b and the common ground bus 28. In an exemplary embodiment, the IMD 20 includes a measuring unit (not shown) and an IMD controller (not shown) in electrical communication with the measuring unit. In a non-restrictive example, the measuring unit applies a small voltage between the positive high-voltage bus 26a and the common ground bus 28, and between the negative high-voltage bus 26b and the common ground bus 28, and detects the resulting current flows. The IMD controller calculates the positive insulation resistance and the negative insulation resistance based on the current detected by the measuring unit.

[0040] In the exemplary embodiment shown in Fig. As shown in Figure 1 and discussed here, the IMD 20 is shown connected between the positive high-voltage bus 26a, the common ground bus 28, and the negative high-voltage bus 26b. It is understood that, because the multiple non-isolating converters 14 do not provide galvanic isolation between the high-voltage and low-voltage sides, the IMD 20 can be connected anywhere in the electric charging station 10 between a positive bus, a negative bus, and the common ground bus 28, including, for example, in the power source 12, near the multiple contactors 18, and / or in the multiple charging handles 16. Furthermore, it is understood that the control system can contain any number of IMDs without deviating from the scope of this disclosure. The IMD 20 communicates electrically with the controller 22, as discussed in more detail below.

[0041] The controller 22 is used to implement a method 100 for operating an electric vehicle charging station, as described below. The controller 22 includes at least one processor 32 and a non-transient computer-readable memory device or computer-readable storage medium 34. The processor 32 can be a custom-made or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 22, a semiconductor-based microprocessor (in the form of a microchip or a chipset), a macroprocessor, a combination thereof, or, more generally, an instruction-executing device.

[0042] The computer-readable storage device or computer-readable storage medium 34 may, for example, contain volatile and non-volatile memory in read-only memory (ROM), read / write memory (RAM), and persistent memory (KAM). KAM is persistent or non-volatile memory that can be used to store various operating variables while the processor 32 is turned off. The computer-readable storage device or computer-readable storage medium 34 may be implemented using a number of storage devices, such as PROMs (programmable read-only memory), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or other electrical, magnetic, optical, or combined storage devices capable of storing data, some of which represent executable instructions used by the controller 22 to perform the procedure 100.The controller 22 can also consist of several controllers that are in electrical communication with each other.

[0043] The controller 22 communicates electrically with the multiple contactors 18 and the IMD 20. In an exemplary embodiment, the electrical communication is established using, for example, a CAN network, a FLEXRAY network, a local area network (e.g., Wi-Fi, Ethernet, and the like), a serial peripheral interface network (SPI network), or the like. It is understood that various additional wired and wireless techniques and communication protocols for communicating with the controller 22 are within the scope of this disclosure. Furthermore, it is understood that, within the scope of this disclosure, electrical communication also includes power and / or energy transfer between electrical devices (e.g., using conductor wires and / or wireless power transmission techniques).

[0044] With reference to Fig.Figure 2 shows a flowchart of the procedure 100 for operating the electric vehicle charging station 10. The procedure 100 begins in block 102 and proceeds to block 104. In block 104, the controller 22 uses the IMD 20 to measure an unloaded insulation resistance of the electric vehicle charging station 10 with no load devices connected. In an exemplary embodiment, the unloaded insulation resistance is measured when each of the multiple contactors 18 is closed, but none of the multiple electric vehicles 24 or other load devices are connected to the multiple charging handles 16. The unloaded insulation resistance includes both an unloaded positive insulation resistance (measured, for example, between the positive high-voltage bus 26a and the common ground bus 28) and an unloaded negative insulation resistance (measured, for example, between the negative high-voltage bus 26b and the common ground bus 28).The unloaded insulation resistance is stored in media 34 for future retrieval. After block 104, procedure 100 continues to block 106.

[0045] In block 106, the controller 22 compares the unloaded insulation resistance determined in block 104 with a predetermined insulation resistance threshold (e.g., 500 Ω / V). If the unloaded positive insulation resistance and / or the unloaded negative insulation resistance are greater than or equal to the predetermined insulation resistance threshold, procedure 100 proceeds to block 108, as discussed in more detail below. If the unloaded positive insulation resistance and / or the unloaded negative insulation resistance are less than the predetermined insulation resistance threshold, procedure 100 proceeds to block 110.

[0046] In block 110, the controller 22 deactivates the electric charging station 10 in response to a determination that the unloaded positive insulation resistance and / or the unloaded negative insulation resistance are less than the specified insulation resistance threshold. In one exemplary embodiment, to deactivate the electric charging station 10, the controller 22 opens each of the multiple contactors 18. In a non-restrictive example, the multiple charging handles 16 are also configured to provide a signal to any connected load devices (e.g., the multiple electric vehicles 24) that charging is unavailable. Following block 110, the method 100 proceeds to enter a standby state in block 112.

[0047] In Block 108, the controller 22 uses the IMD 20 to measure a first loaded insulation resistance, wherein a first load device is connected to the first non-insulating converter 14a. In an exemplary embodiment, the first load device is the first vehicle 24a. In a non-restrictive example, the first loaded insulation resistance is measured with each of the multiple contactors 18 closed, the first vehicle 24a connected to the first charging handle 16a, and no vehicle or load connected to the second charging handle 16b. The first loaded insulation resistance comprises a first loaded positive insulation resistance (measured, for example, between the positive high-voltage bus 26a and the common ground bus 28) and a first loaded negative insulation resistance (measured, for example, between the negative high-voltage bus 26b and the common ground bus 28).The first loaded insulation resistance value is stored in media 34 for future retrieval. After block 108, procedure 100 continues to block 114.

[0048] In block 114, the controller 22 compares the first loaded insulation resistance, determined in block 108, with the specified insulation resistance threshold (e.g., 500 Ω / V). If the first loaded positive insulation resistance and / or the first loaded negative insulation resistance are greater than or equal to the specified insulation resistance threshold, procedure 100 proceeds to block 116, as discussed in more detail below. If the first loaded positive insulation resistance and / or the first loaded negative insulation resistance are less than the specified insulation resistance threshold, procedure 100 proceeds to block 118.

[0049] In block 118, the controller 22 disconnects the first load device (e.g., the first vehicle 24a) in response to a determination that the first loaded positive insulation resistance and / or the first loaded negative insulation resistance are less than the specified insulation resistance threshold. In an exemplary embodiment, to disconnect the first load device (e.g., the first vehicle 24a), the controller 22 opens the first contactor 18a and the second contactor 18b. In a non-restrictive example, the first charging handle 16a is also configured to provide a signal to the first load device (e.g., the first vehicle 24a) that charging is unavailable. Following block 118, the method 100 proceeds to enter the standby state in block 112.

[0050] In Block 116, the controller 22 uses the IMD 20 to measure a second loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter 14a and a second load device is connected to the second non-insulating converter 14b. In an exemplary embodiment, the first load device is the first vehicle 24a and the second load device is the second vehicle 24b. In a non-restrictive example, the second loaded insulation resistance is measured with each of the multiple contactors 18 closed, the first vehicle 24a connected to the first charging handle 16a, and the second vehicle 24b connected to the second charging handle 16b. The second loaded insulation resistance includes a second loaded positive insulation resistance (e.g.,The process measures the resistance of two loads: one load is measured between the positive high-voltage bus 26a and the common ground bus 28, and a second load is measured between the negative high-voltage bus 26b and the common ground bus 28. The second load is stored in media 34 for future retrieval. After block 116, procedure 100 proceeds to block 120.

[0051] In block 120, the controller 22 compares the second loaded insulation resistance, determined in block 116, with the predefined insulation resistance threshold (e.g., 500 Ω / V). If the second loaded positive insulation resistance and / or the second loaded negative insulation resistance is greater than or equal to the predefined insulation resistance threshold, procedure 100 proceeds to block 112 to enter standby mode. If the second loaded positive insulation resistance and / or the second loaded negative insulation resistance is less than the predefined insulation resistance threshold, procedure 100 proceeds to blocks 122 and 124.

[0052] In block 122, the controller 22 determines an insulation resistance of the first load device. Within the scope of this disclosure, the insulation resistance of the first load device is an insulation resistance of the circuit arrangement of the first load device itself. The insulation resistance of the first load device comprises a positive insulation resistance of the first load device (measured, for example, between a positive voltage bus of the first load device and a chassis ground of the first load device) and a negative insulation resistance of the first load device (measured, for example, between a negative voltage bus of the first load device and a chassis ground of the first load device). In a non-restrictive example, the first load device is the first vehicle 24a.In an exemplary embodiment, the insulation resistance of the first load device is determined at least partially based on the unloaded insulation resistance determined in Block 104 and the first loaded insulation resistance determined in Block 108. In a non-restrictive example, the positive insulation resistance of the first load device is determined using the following equation: RI,L,1+=[VSVL,1∗[1RI,S,1+−1RI,S,e,+]]−1 where RI,L,1+ The positive insulation resistance of the first load device is V S The high voltage of the electric charging station is 10 V. L,1 a voltage of the first load device (e.g. a traction battery voltage of the first vehicle 24a) is, RI,S,1+ the first loaded positive insulation resistance is determined in block 108, and RI,S,e,+ The unloaded positive insulation resistance is determined in block 104.

[0053] In a non-restrictive example, the negative insulation resistance of the first load device is determined using the following equation: RI,L,1−[1RI,S,1−−1RI,S,e−−[1−VL,1VS∗1RI,L,1+]]−1 where RI,L,1− the negative insulation resistance of the first load device is, RI,S,1− the first loaded negative insulation resistance is determined in block 108, RI,S,e,− The unloaded negative insulation resistance, which is determined in block 104, is V L,1 the voltage of the first load device (e.g. a traction battery voltage of the first vehicle 24a) is, V S is the high voltage of the electric charging station 10 and RI,L,1+ the positive insulation resistance of the first load device (which is determined, for example, using equation 1).

[0054] In one exemplary embodiment, if the insulation resistance of the first load device is less than a predetermined load device resistance threshold, the first contactor 18a and the second contactor 18b are opened. In another exemplary embodiment, the insulation resistance of the first load device is forwarded to a controller of the first load device (e.g., a vehicle controller of the first vehicle 24a) for diagnostic purposes. After block 122, method 100 proceeds to block 126, as discussed in more detail below.

[0055] In block 124, the controller 22 determines an insulation resistance of the second load device. For the purposes of this disclosure, the insulation resistance of the second load device is an insulation resistance of the circuit arrangement of the second load device itself. The insulation resistance of the second load device comprises a positive insulation resistance of the second load device (measured, for example, between a positive voltage bus of the second load device and a chassis ground of the second load device) and a negative insulation resistance of the second load device (measured, for example, between a negative voltage bus of the second load device and a chassis ground of the second load device). In a non-restrictive example, the second load device is the second vehicle 24b.In an exemplary embodiment, the insulation resistance of the second load device is determined at least partially based on the unloaded insulation resistance determined in Block 104, the first loaded insulation resistance determined in Block 108, and the second loaded insulation resistance determined in Block 116. In a non-restrictive example, the positive insulation resistance of the second load device is determined using the following equation: RI,L,2+=[VSVL,2∗[1RI,S,2+−1RI,S,1+]]−1 where RI,L,2+ The positive insulation resistance of the second load device is V S The high voltage of electric charging station 10 is V L,2 a voltage of the second load device (e.g. a traction battery voltage of the second vehicle 24b) is, RI,S,2+ the second loaded positive insulation resistance is determined in block 116, and RI,S,1+ the first loaded positive insulation resistance is determined in block 108.

[0056] In a non-restrictive example, the negative insulation resistance of the second load device is determined using the following equation: RI,L,2−=[1RI,S,2−−1RI,S,e−−[1−VL,2VS∗1RI,L,2+]]−1 where RI,L,2− the negative insulation resistance of the second load device is, RI,S,2− the second loaded negative insulation resistance is determined in block 116, RI,S,e,− The unloaded negative insulation resistance, which is determined in block 104, is V L,2 the voltage of the second load device (e.g. a traction battery voltage of the second vehicle 24b) is V S the high voltage of electric charging station 10 is and RI,L,2+ the positive insulation resistance of the second load device (which is determined, for example, using equation 3).

[0057] In one exemplary embodiment, if the insulation resistance of the second load device is less than a predetermined load device resistance threshold, the third contactor 18c and the fourth contactor 18d are opened. In another exemplary embodiment, the insulation resistance of the second load device is forwarded to a controller of the second load device (e.g., a vehicle controller of the second vehicle 24b) for diagnostic purposes. After block 124, method 100 proceeds to block 126.

[0058] In block 126, the controller 22 compares the insulation resistance of the first load device, determined in block 122, with the insulation resistance of the second load device, determined in block 124. If the positive insulation resistance or the negative insulation resistance of the first load device is less than the positive insulation resistance or the negative insulation resistance of the second load device, procedure 100 proceeds to block 128, as discussed in more detail below. If the positive insulation resistance or the negative insulation resistance of the second load device is less than the positive insulation resistance or the negative insulation resistance of the first load device, procedure 100 proceeds to block 130.

[0059] In block 130, the controller 22 disconnects the second load device (e.g., the second vehicle 24b) in response to a determination that the second loaded insulation resistance is less than the predetermined insulation resistance threshold, and that the positive or negative insulation resistance of the second load device is less than the positive or negative insulation resistance of the first load device. In an exemplary embodiment, to disconnect the second load device (e.g., the second vehicle 24b), the controller 22 opens the third contactor 18c and the fourth contactor 18d. In a non-restrictive example, the second charging handle 16b is also configured to provide a signal to the second load device (e.g., the second vehicle 24b) that charging is unavailable.By disconnecting the load device that has the lowest insulation resistance, the overall insulation resistance of the electric charging station 10 is increased, which allows continued operation of the electric charging station 10 and the supply of further load devices (e.g. the first vehicle 24a).

[0060] In an exemplary embodiment, after disconnecting the second load device, the second loaded insulation resistance is measured again and compared with the predetermined insulation resistance threshold. If the second loaded insulation resistance is still less than the predetermined insulation resistance threshold, the controller 22 also disconnects the first load device, as discussed below. After block 130, the method 100 proceeds to enter the standby state in block 112.

[0061] In block 128, the controller 22 disconnects the first load device (e.g., the first vehicle 24a) in response to a determination that the second loaded insulation resistance is less than the predetermined insulation resistance threshold and that the positive or negative insulation resistance of the first load device is less than the positive or negative insulation resistance of the second load device. In an exemplary embodiment, to disconnect the first load device (e.g., the first vehicle 24a), the controller 22 opens the first contactor 18a and the second contactor 18b. In a non-restrictive example, the first charging handle 16a is also configured to provide a signal to the first load device (e.g., the first vehicle 24a) that charging is unavailable.By disconnecting the load device that has the lowest insulation resistance, the overall insulation resistance of the electric charging station 10 is increased, which allows continued operation of the electric charging station 10 and the supply of further load devices (e.g. the second vehicle 24b).

[0062] In an exemplary embodiment, after the first load device is disconnected, the second loaded insulation resistance is measured again and compared with the predetermined insulation resistance threshold. If the second loaded insulation resistance is still less than the predetermined insulation resistance threshold, the controller 22 also disconnects the second load device, as discussed above. After block 128, the method 100 proceeds to enter the standby state in block 112.

[0063] In one exemplary embodiment, the controller 22 repeatedly exits the standby state 112 and restarts the procedure 100 in block 102. In a non-restrictive example, the controller 22 exits the standby state 112 based on a timer, e.g., every three hundred milliseconds, and restarts the procedure 100.

[0064] While method 100 is described for an exemplary embodiment comprising two vehicles, it should be understood that the electric charging station 10 and method 100 are applicable to any electric charging system, including, for example, electric commercial vehicle charging systems, charging systems for electrical consumer devices (e.g., tools, laptops, smartphones, household appliances), and / or the like. Furthermore, the electric charging station 10 and method 100 are applicable to any number of load devices (e.g., more than two vehicles or additional load devices).

[0065] The electric charging station 10 and the method 100 of the present disclosure offer several advantages. Compared to conventional charging systems, the electric charging station 10 of the present disclosure offers, for example, increased efficiency, reduced resource consumption, reduced size, and reduced weight due to the use of non-isolated converters. Using the method 100 of the present disclosure, insulation faults in the electric charging station 10 or connected load devices are identified, located, and isolated in order to minimize interference with other components of the electric charging station 10 and / or connected load devices. Using the method 100, the electric charging station 10 can remain at least partially functional even when a fault condition is detected.

[0066] The description of the present revelation is merely exemplary, and it is intended that variations that do not deviate from the main content of the present revelation remain within its scope. Such variations should not be considered a deviation from the idea and scope of the present revelation.

Claims

[1] Method for operating an electric vehicle charging station, comprising: Measuring the unloaded insulation resistance of the electric vehicle charging station with no load devices connected; Measuring the insulation resistance of an electric vehicle charging station under load, wherein two or more load devices are connected to the electric vehicle charging station and the two or more load devices are in electrical communication with each other via the electric vehicle charging station; and Modifying the operation of the electric vehicle charging station, at least partially, based on the unloaded insulation resistance and / or the loaded insulation resistance. [2] Method according to claim 1, wherein measuring the unloaded insulation resistance further comprises: Measuring the unloaded insulation resistance of the electric charging station, wherein the electric charging station includes a power source and several uninsulated converters for connecting each of the two or more load devices to the power source, and the unloaded insulation resistance comprises an unloaded positive insulation resistance and an unloaded negative insulation resistance. [3] Method according to claim 2, wherein measuring the loaded insulation resistance further comprises: Measuring a first loaded insulation resistance, wherein a first load device is connected to a first non-insulating converter of the electric charging station; and Measuring a second loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric charging station and a second load device is connected to a second non-insulating converter of the electric charging station. [4] The method of claim 3, wherein changing the operation of the electric charging station further comprises: Determining the insulation resistance of the first load device at least partially based on the unloaded insulation resistance and the first loaded insulation resistance; Determining the insulation resistance of the second load device at least partially based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance. Changing the operation of the electric vehicle charging station, at least partially, based on the insulation resistance of the first load device and / or the insulation resistance of the second load device. [5] Method according to claim 3, wherein measuring the loaded insulation resistance further comprises: Measuring the first loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric charging station, and the first loaded insulation resistance comprises a first loaded positive insulation resistance and a first loaded negative insulation resistance; and Measuring the second loaded insulation resistance, wherein the first load device is connected to the first non-insulating converter of the electric charging station, the second load device is connected to the second non-insulating converter of the electric charging station, and the second loaded insulation resistance comprises a second loaded positive insulation resistance and a second loaded negative insulation resistance. [6] The method of claim 5, wherein changing the operation of the electric charging station further comprises: Determining an insulation resistance of the first load device at least partially on the basis of the unloaded insulation resistance and the first loaded insulation resistance, wherein the insulation resistance of the first load device comprises a positive insulation resistance of the first load device and a negative insulation resistance of the first load device; Determining an insulation resistance of the second load device at least partially based on the unloaded insulation resistance, the first loaded insulation resistance, and the second loaded insulation resistance, wherein the insulation resistance of the second load device comprises a positive insulation resistance of the second load device and a negative insulation resistance of the second load device; and Changing the operation of the electric vehicle charging station, at least partially, based on the positive insulation resistance of the first load device and / or the negative insulation resistance of the first load device and / or the positive insulation resistance of the second load device and / or the negative insulation resistance of the second load device. [7] Method according to claim 6, wherein determining the insulation resistance of the first load device further comprises: Determining the positive insulation resistance of the first load device using the following equation: RI,L,1+=[VSVL,1∗[1RI,S,1+−1RI,S,e,+]]−1 where RI,L,1+ The positive insulation resistance of the first load device is V S a high voltage of the electric charging station is, V L,1 a voltage of the first load device is RI,S,1+ the first loaded positive insulation resistance is and RI,S,e,+ the unloaded positive insulation resistance is; and Determining the negative insulation resistance of the first load device using the following equation: RI,L,1−[1RI,S,1−−1RI,S,e−−[1−VL,1VS∗1RI,L,1+]]−1 where RI,L,1− the negative insulation resistance of the first load device is, RI,S,1− the first loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,1 the voltage of the first load device is, V S the high voltage of the electric charging station is and RI,L,1+ The positive insulation resistance of the first load device is [value missing]. [8] Method according to claim 6, wherein determining the insulation resistance of the second load device further comprises: Determining the positive insulation resistance of the second load device using the following equation: RI,L,2+=[VSVL,2∗[1RI,S,2+−1RI,S,1+]]−1 where RI,L,2+ The positive insulation resistance of the second load device is V S a high voltage of the electric charging station is, V L,2 a voltage of the second load device is RI,S,2+ the second loaded positive insulation resistance is and RI,S,1+ the first loaded positive insulation resistance is; and Determining the negative insulation resistance of the second load device using the following equation: RI,L,2−=[1RI,S,2−−1RI,S,e−−[1−VL,2VS∗1RI,L,2+]]−1 where RI,L,2− the negative insulation resistance of the second load device is, RI,S,2− the second loaded negative insulation resistance is, RI,S,e,− the unloaded negative insulation resistance is V L,2 The voltage of the second load device is V s the high voltage of the electric charging station is and RI,L,2+ The positive insulation resistance of the second load device is [value missing]. [9] The method of claim 6, wherein changing the operation of the electric charging station further comprises: Comparing the second loaded insulation resistance with a predetermined insulation resistance threshold and Disconnecting the first load device and / or the second load device from the electric charging station in response to a determination that the second loaded insulation resistance is less than the specified insulation resistance threshold, at least partially based on the positive insulation resistance of the first load device and / or the negative insulation resistance of the first load device and / or the positive insulation resistance of the second load device and / or the negative insulation resistance of the second load device. [10] The method of claim 9, wherein separating the first load device and / or the second load device further comprises: Disconnecting the first load device in response to a finding that the positive insulation resistance of the first load device is less than the positive insulation resistance of the second load device, or that the negative insulation resistance of the first load device is less than the negative insulation resistance of the second load device; and Disconnecting the second load device in response to a finding that the positive insulation resistance of the second load device is less than the positive insulation resistance of the first load device, or that the negative insulation resistance of the second load device is less than the negative insulation resistance of the first load device.

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