On-board Charger (OBC) Method and System

Abstract

The present application relates to on-board charger (OBC) methods and systems. An on-board battery charger (OBC) includes first and second rails that generate a first detection signal and a second detection signal based on a voltage event such as a zero-crossing or peak voltage event of an input voltage provided to the rail circuit. The OBC includes a relay that can switch between (i) an open state and (ii) a closed state. In the open state, the relay disconnects the rails so that the rails can receive a first-phase input voltage and a second-phase input voltage from a polyphase mains power supply, respectively. In the closed state, the relay connects the rails so that the rails can both receive the same input voltage from a single-phase mains power supply. A controller determines whether the input voltages received by the rails from the mains power supply are out of phase or in phase based on a comparison of the detection signals at the same time, in order to determine therefrom whether the mains power supply is polyphase or single-phase and / or whether the relay is properly or improperly open or closed.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 143,117, filed on Jan. 29, 2021, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to methods and systems for controlling a charger (e.g., a multiphase (i.e., multi - track) on - vehicle battery charger of an electric vehicle). Background

[0004] An on - vehicle battery charger (OBC) of an electric vehicle (EV) is used to charge the traction battery of the EV. The OBC converts the electrical power absorbed from an AC power source into DC electrical power and uses the DC electrical power to charge the battery. Summary

[0005] One objective includes a method and system for controlling an on - vehicle battery charger (OBC) of an electric vehicle (EV) to detect a phase shift between input voltages received by the OBC from a mains power supply, and thereby determine whether the mains power supply is a multiphase mains power supply or a single - phase mains power supply and / or whether the phase (i.e., track) configuration relay of the OBC is properly or improperly positioned in its open state or closed state.

[0006] An OBC is provided that includes a first track (i.e., track circuit), a second track circuit, a relay, and a main controller. The first track circuit has a first track controller configured to generate a first detection signal based on a voltage event of an input voltage provided to the first track circuit. The second track circuit has a second track controller configured to generate a second detection signal based on a voltage event of an input voltage provided to the second track circuit. The relay is switchable between (i) an open state and (ii) a closed state. In the open state, the relay disconnects the track circuits such that the first track circuit and the second track circuit are configured to receive a first - phase input voltage and a second - phase input voltage respectively from a multiphase mains power supply. In the closed state, the relay connects the track circuits such that the track circuits are configured to receive the same input voltage from a single - phase mains power supply.

[0007] The master controller is configured to determine whether the input voltage supplied from the mains power supply to the first track circuit and the input voltage supplied from the mains power supply to the second track circuit are out of phase (i.e., non-zero phase shift) or in phase (i.e., phase shift is 0°) based on a comparison of the first detection signal at a given time and the second detection signal at the given time, to determine therefrom whether the mains power supply is a polyphase mains power supply or a single-phase mains power supply and / or whether the relay is properly or improperly positioned in the open state or the closed state.

[0008] The voltage event can be a threshold voltage event, such as a zero-crossing voltage event or a peak voltage event.

[0009] The master controller can also be configured to pause the operation of at least one of the track circuits when the mains power supply is a polyphase mains power supply and the relay is improperly in the closed state and the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase. The master controller can also be configured to retry switching the relay from the closed state to the open state when the operation of at least one of the track circuits is paused.

[0010] The master controller can also be configured to continue the operation of the track circuits when the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase when the mains power supply is a single-phase mains power supply, and when the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are out of phase when the mains power supply is a polyphase mains power supply.

[0011] The OBC can also include a third track circuit and a second relay. The third track circuit has a third track controller that is configured to generate a third detection signal based on a voltage event of the input voltage supplied to the third track circuit. The second relay can be switched between (i) an open state and (ii) a closed state. In the open state, the second relay disconnects the first track circuit and the third track circuit, such that the first track circuit and the third track circuit are configured to receive a first-phase input voltage and a third-phase input voltage from the polyphase mains power supply, respectively. In the closed state, the second relay connects the first track circuit and the third track circuit, such that the first track circuit and the third track circuit are configured to both receive the same input voltage from the single-phase mains power supply. The master controller is also configured to determine whether the input voltage supplied from the mains power supply to the first track circuit and the input voltage supplied from the mains power supply to the third track circuit are out of phase (e.g., phase shift is 120° or 240°) or in phase based on a comparison of the first detection signal at a given time and the third detection signal at the given time, to determine therefrom whether the mains power supply is a three-phase mains power supply or a single-phase mains power supply and / or whether the second relay is properly or improperly positioned in the open state or the closed state.

[0012] The master controller may also be configured to pause the operation of at least one of the track circuits when the mains power supply is a three-phase mains power supply and at least one of the relays is inappropriately in the closed state and at least two of the input voltages in the input voltage supplied to the track circuit are in phase. The master controller may also be configured to retry switching at least one of the relays from the closed state to the open state when the operation of at least one of the track circuits is paused.

[0013] The master controller may also be configured to continue the operation of the track circuits when the input voltage supplied to the track circuit is in phase when the mains power supply is a single-phase mains power supply and when the input voltage supplied to the track circuit is out of phase when the mains power supply is a three-phase mains power supply.

[0014] A related method for use with an OBC is also provided.

[0015] A method for use with an on-board battery charger (OBC) is provided, the on-board battery charger (OBC) including a first track circuit having a first track controller, a second track circuit having a second track controller, a relay, and a master controller, the relay being switchable between (i) an open state and (ii) a closed state, in the open state, the relay disconnects the track circuits such that the first track circuit and the second track circuit are configured to receive a first-phase input voltage and a second-phase input voltage respectively from a polyphase mains power supply, in the closed state, the relay connects the track circuits such that the track circuits are configured to both receive the same input voltage from a single-phase mains power supply, the method including:

[0016] The first track controller generates a first detection signal based on a voltage event of the input voltage supplied to the first track circuit;

[0017] The second track controller generates a second detection signal based on a voltage event of the input voltage supplied to the second track circuit; and

[0018] The master controller determines whether the input voltage supplied from the mains power supply to the first track circuit and the input voltage supplied from the mains power supply to the second track circuit are out of phase or in phase based on a comparison of the first detection signal at a given time and the second detection signal at a given time, to thereby determine whether the mains power supply is a polyphase mains power supply or a single-phase mains power supply and / or whether the relay is appropriately or inappropriately positioned in the open state or the closed state.

[0019] The voltage event is a threshold voltage event.

[0020] The threshold voltage event is a zero-crossing voltage event or a peak voltage event.

[0021] The method further includes: when the mains power supply is a polyphase mains power supply and the relay is inappropriately in the closed state, and when the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase, the main controller pauses the operation of at least one of the track circuits.

[0022] The method further includes: when the operation of at least one of the track circuits is paused, the main controller retries to switch the relay from the closed state to the open state.

[0023] The OBC further includes a third track circuit and a second relay. The third track circuit has a third track controller. The second relay can be switched between (i) an open state and (ii) a closed state. In the open state of the second relay, the second relay disconnects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to receive a first-phase input voltage and a third-phase input voltage from the polyphase mains power supply respectively. In the closed state of the second relay, the second relay connects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to both receive the same input voltage from a single-phase mains power supply. The method includes:

[0024] The third track controller generates a third detection signal based on a voltage event of the input voltage supplied to the third track circuit; and

[0025] The main controller determines whether the input voltage supplied to the first track circuit from the mains power supply and the input voltage supplied to the third track circuit from the mains power supply are out of phase or in phase according to the comparison of the first detection signal at a given time and the third detection signal at a given time, so as to determine whether the mains power supply is a three-phase mains power supply or a single-phase mains power supply and / or whether the second relay is appropriately or inappropriately positioned in the open state or the closed state.

[0026] The voltage event is a zero-crossing voltage event or a peak voltage event. Brief Description of the Drawings

[0027] Figure 1 A block diagram of an electrical system having a polyphase (i.e., multi-track) on-board battery charger (OBC) is shown;

[0028] Figure 2A A block diagram of the electrical system is shown, in which the OBC is detailed as a three-phase (i.e., multi-track) OBC, which has three phases (i.e., tracks), and there is also an input relay between the tracks, and the mains power supply of the electrical system is a three-phase mains power supply;

[0029] Figure 2B Shown as Figure 2A The block diagram of the electrical system shown, but where the mains power supply is a single-phase mains power supply;

[0030] Figure 3 A block diagram of the OBC is shown, depicting each of the track controllers of the OBC's tracks and their communication arrangement with the OBC's main controller;

[0031] Figure 4 A first graph and a second graph are shown. The first graph has a curve of the AC input voltage, and the second graph has a first curve of the zero-crossing event circuit output of the track controller based on the AC input voltage and a second curve of the zero-crossing event timer output of the track controller based on the AC input voltage;

[0032] Figure 5A A first graph, a second graph, and a third graph are shown. The first graph has first, second, and third curves of the (unrectified) first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage. The second graph has first, second, and third curves of the zero-crossing event circuit outputs of the first, second, and third track controllers respectively based on the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage, and the third graph has first, second, and third curves of the zero-crossing event timer outputs of the first, second, and third track controllers respectively based on the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage;

[0033] Figure 5B A first graph, a second graph, and a third graph are shown. The first graph has first, second, and third curves of the (rectified) first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage. The second graph has first, second, and third curves of the zero-crossing event circuit outputs of the first, second, and third track controllers respectively based on the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage, and the third graph has first, second, and third curves of the zero-crossing event timer outputs of the first, second, and third track controllers respectively based on the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage;

[0034] Figure 6showing a first graph having first, second and third graphs of zero crossing event timer outputs of the first, second and third track controllers based on (unrectified) first, second and third phase AC input voltages provided to the OBC from a three-phase mains power supply when the relays of the OBC are suitably positioned in their disconnected positions (i.e., their rest positions) so that the tracks of the OBC are each suitably directly connected to the OBC;

[0035] Figure 6 Also shown is a second graph having first, second and third graphs of zero crossing event timer outputs of the first, second and third track controllers based on an (unrectified) AC input voltage provided to the OBC from a single phase mains power supply when the relays of the OBC are properly positioned in their closed positions so that the tracks of the OBC are properly connected to the OBC as a single entity;

[0036] Figure 6 Also shown is a third graph having first, second and third graphs of zero-crossing event timer outputs of the first, second and third rail controllers based on (unrectified) first, second and third phase AC input voltages provided to the OBC from a three-phase mains power source when (i) the first input relay of the OBC is improperly positioned in its closed position so that the second rail of the OBC is improperly connected to the OBC as a single entity with the first rail of the OBC and (ii) the second input relay of the OBC is properly positioned in its open position so that the third rail of the OBC is properly connected separately to the OBC;

[0037] Figure 7A showing a block diagram of an OBC depicting a first track controller for a first track of the OBC and an nth track controller for an nth track of the OBC; and

[0038] Figure 7B , Figure 7C and Figure 7D A flow chart is shown depicting the operation of a method and system for detecting the phase configuration of a mains power supply to which an OBC is connected, and for diagnosing the operating state of an input relay of the OBC, which is used to change the phase (i.e., rail) configuration of the OBC to be compatible with whether the mains power supply is multi-phase or single-phase. Detailed Description

[0039] Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples of the invention, which can be embodied in various and alternative forms. The drawings are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Thus, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching one skilled in the art to employ the invention in different ways.

[0040] Now referring to Figure 1 , a block diagram of an electrical system 10 having an on-board battery charger (OBC) 12 is shown. The OBC 12 is "mounted" on an electric vehicle (EV). As used herein, the terms "electric vehicle" and "EV" encompass any type of vehicle that uses electric power for vehicle propulsion, including battery electric vehicles (BEV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and the like. The OBC 12 is used to charge the traction battery 14 of the EV. The traction battery 14 is a high voltage (HV) direct current (DC) traction battery according to the electrical energy requirements for vehicle propulsion.

[0041] The electrical system 10 also includes an alternating current (AC) power source, such as the mains power supply 16 of the power grid. The OBC 12 uses the electrical power from the mains power supply 16 to charge the traction battery 14. The OBC 12 is connected to the mains power supply 16 via an external electric vehicle supply equipment (EVSE) 18 to absorb electrical power from the mains power supply. The OBC 12 converts the electrical power absorbed from the mains power supply 16 into DC electrical power. The OBC 12 outputs the DC electrical power to the traction battery 14 via the vehicle's HV DC bus for charging the traction battery.

[0042] A main controller ("controller") 20 is associated with the OBC 12. The controller 20 is an electronic device, such as a processor, a microcontroller, or the like (e.g., a computer) (e.g., a vehicle controller) mounted on the EV. The controller 20 communicates with the OBC 12 to control the operation of the OBC. The controller 20 controls the OBC 12 to convert the electrical power from the mains power supply 16 into DC electrical power and charge the traction battery 14 with the DC electrical power. The controller 20 may be integrated within the OBC unit. The controller 20 may provide general commands and communicate with other vehicle units and phase (rail) - specific controllers responsible for phase (rail) operation, control, and real - time diagnosis. The controller 20 is also operable to communicate with and control other nodes of the electrical system 10 and the EV, and these other nodes include the nodes involved in the charging application.

[0043] Now referring to Figure 2A and Figure 2B , continuing to refer toFigure 1 , a block diagram of an electrical system 10 with a detailed depiction of an OBC 12 is shown. The OBC 12 is an N-phase (i.e., N-rail) OBC, where N is an integer greater than 1. Thus, the OBC 12 is a polyphase (i.e., multi-rail) OBC with at least two phases (i.e., rails (or branches)). For example, as Figure 2A and Figure 2B shown, the OBC 12 is a three-phase (or three-rail) OBC having a first rail 22a, a second rail 22b, and a third rail 22c (collectively referred to as "rails 22") (each labeled as an "inner phase" in Figure 2A and Figure 2B ).

[0044] The rails (i.e., track circuits) 22 have the same electrical circuit for converting electrical power from the utility power supply 16 into DC electrical power to charge the traction battery 14. For example, each of the rails 22a, 22b, and 22c has an AC electromagnetic interference (EMI) input filter, followed in sequence by a power factor corrector (PFC), a DC link capacitor, a DC / DC converter, and an output filter (not shown). The controller 20, together with the track controllers of the rails 22 (discussed below), controls the following operations of the electrical circuit of the rails 22: converting electrical power from the utility power supply 16 into DC electrical power and delivering the DC electrical power to the traction battery 14. More specifically, in an embodiment, the "main controller" is inside the OBC, and three "inner phase controllers" (or "track controllers") are associated with the three rails 22 respectively. The combination of these four controllers can be understood to provide the "controller" function.

[0045] Each of the rails 22a, 22b, and 22c is connected to the utility power supply 16 via an EVSE 18 so that the rail absorbs electrical power from the utility power supply and converts the absorbed electrical power into DC electrical power for charging the traction battery 14. The rails 22 are located between the input end of the OBC and the output end of the OBC, the input end is connected to the utility power supply 16 via an EVSE 18, and the output end is connected to the traction battery 14 via the HV DC bus of the vehicle.

[0046] Strictly for example, each of the rails 22a, 22b, and 22c can deliver 3.6 kW of electrical power for charging the traction battery 14. Thus, in this example, the OBC 12 can deliver 10.8 kW (3 * 3.6 kW) of electrical power for charging the traction battery 14 (i.e., in this example, the OBC 12 is an "11 kW" OBC).

[0047] The OBC 12 also includes input relays (or switches) 24a and 24b (collectively referred to as "input relay 24"). The input relay 24a is located between the input ends of the tracks 22a and 22b. The input relay 24b is located between the input ends of the tracks 22a and 22c. Each of the input relays 24a and 24b can be switched between an open state and a closed state. The controller 20 is operable to control the switching of the input relay 24.

[0048] A closed input relay connects the input ends of the two tracks between which the input relay is interposed. Conversely, an open input relay disconnects the two tracks between which the input relay is interposed. The input relay 24 is shown in Figure 2A as being in the open state (i.e., the reset position). Thus, when the input relay 24a between the tracks 22a and 22b is open, the input end of the track 22b is not connected to the input end of the track 22a. Similarly, when the input relay 24b between the tracks 22a and 22c is open, the track 22c is not connected to the input end of the track 22a. The input relay 24 is shown in Figure 2B as being in the closed state. Thus, when the input relay 24a between the tracks 22a and 22b is closed, the input end of the track 22b is connected to the input end of the track 22a. Similarly, when the input relay 24b between the tracks 22a and 22c is closed, the track 22c is connected to the input end of the track 22a.

[0049] The mains power supply 16 is a polyphase mains power supply or a single-phase mains power supply. Typically, as a polyphase mains power supply, the mains power supply 16 is a three-phase mains power supply. The input relay 24 is used to enable the OBC 12 to be used interchangeably with a polyphase mains power supply and a single-phase mains power supply.

[0050] In either case where the mains power supply is polyphase or single-phase, the track 22a is directly connected to the mains power supply 16 separately via the EVSE 18. In the case where the mains power supply 16 is polyphase, the controller 20 controls the input relay 24 to be open ( Figure 2A as shown in). In this case, in addition to the track 22a being directly connected to the mains power supply 16 separately via the EVSE 18, the tracks 22b and 22c are also directly connected to the mains power supply separately via the EVSE. In the case where the mains power supply 16 is single-phase, the controller 20 controls the input relay 24 to be closed ( Figure 2B as shown in). In this case, the tracks 22b and 22c are combined with the track 22a to be connected to the mains power supply 16 together with the track 22a.

[0051] In Figure 2A the mains power supply 16 is a three-phase mains power supply. In this case, the input relay 24 will be controlled to be open (the input relay 24 is inFigure 2A is shown as disconnected in, so that all three rails 22 can be directly connected to the mains power supply 16 individually via the EVSE 18. In particular, each of the rails 22a, 22b, 22c is directly connected to the corresponding lines L1, L2, L3 of the mains power supply 16 via the respective nodes L 1’ , L 2’ , L 3’ of the OBC 12, and is directly connected to the neutral line N of the mains power supply via the neutral node N' of the OBC.

[0052] In Figure 2B , the mains power supply 16 is a single-phase mains power supply. In this case, the input relay 24 will be controlled to be closed (the input relay 24 is shown as closed in Figure 2B ), so that the rail 22a is directly connected to the mains power supply 16 individually via the EVSE 18, and the rails 22b and 22c are connected to the rail 22a to be connected to the mains power supply. In particular, the rail 22a is directly connected to the corresponding line L1 of the mains power supply 16 via the node L 1’ of the OBC 12, and is directly connected to the neutral line N of the mains power supply via the neutral node N' of the OBC; and the rails 22b and 22b are directly connected to the node L 1’ of the OBC 12 and to the neutral node N' of the OBC via the closed input relays 24a and 24b.

[0053] As described above, the OBC for EVs that can work with single-phase (1-ph) and three-phase (3-ph) AC grids with available N is typically designed with three internal rails (or modules) 22 that share the neutral node N' of the OBC. In the case of a 1-ph AC grid, the rails 22b and 22c can be switched to the L 1’ node of the OBC. As further described, the OBC is not directly connected to the grid, but is connected to the grid through the EVSE, which acts as an additional element to ensure that the OBC is safely and controllably connected to the AC grid. When both the EVSE and the OBC are ready for the charging operation, the EVSE closes its contactor, and the OBC receives the AC voltage supply from the AC grid.

[0054] As a reference, considering different voltage ranges, as well as different AC grid frequencies or phases, SAE-J1772, IEC-61851, and GB / T 20234 cover a relatively wide range of domestic networks. A configurable OBC is desired that covers all AC grid possibilities within the same device. As described above, the OBCs designed to support single-phase and three-phase grids are typically based on internal rails (i.e., modules) that are connected to the live phases accordingly to allow their operation.

[0055] Embodiments of the present invention provide a method and a system for detecting the characteristics of an AC power grid connected to an OBC and for diagnosing the input relay (or switch) of the OBC related to the multi-phase configuration and single-phase configuration of the OBC (i.e., the multi-track configuration and single-track configuration of the OBC). That is, embodiments of the present invention provide a method and a system for detecting the phase (i.e., track) configuration of the mains power supply to which the OBC is connected and for diagnosing the operating state of the input relay of the OBC, which is used to implement the phase configuration of the OBC to be compatible with whether the mains power supply is multi-phase or single-phase.

[0056] For further reference, most EVSEs are not prepared to communicate to the OBC which type of power grid (multi-phase mains power supply or single-phase mains power supply) will supply AC electric power to the OBC. Therefore, according to embodiments of the present invention, the OBC is configured to identify the type of power grid supplying AC electric power to the OBC and to configure the track switch of the OBC to correspond to the AC voltage present at the input of the OBC. According to embodiments of the present invention, the OBC is also configured with a mechanism to diagnose the integrity of the input relay of the OBC, which allows the tracks of the OBC to commute from one track to another in order to determine which tracks of the OBC and which corresponding input relays of the OBC are in proper condition to handle power. A less cost-effective solution for diagnosing the integrity of the input relay is to use a specific circuit dedicated to this purpose.

[0057] In summary, according to embodiments of the present invention, the OBC has the following characteristics: the OBC is capable of charging from 3-phase and 1-phase power grids; the OBC can detect the AC power grid to which it is connected and ensure the provision of appropriate voltage; then, the OBC can switch the internal configuration relay accordingly; and, the OBC can ensure that the relay works properly before the charging process starts. By having these characteristics, the OBC is capable of diagnosing both the AC power grid and the relay.

[0058] Now referring to Figure 3 and continuing to refer to Figure 1 , Figure 2A and Figure 2B , a block diagram of the OBC 12 is shown. Due to cost and for functional isolation between the tracks 22 of the OBC 12, each track 22 is typically controlled by its own independent controller 52, which only sees what happens on its own track. In the Figure 3 block diagram, the individual controllers 52a ("CTRL1"), 52b ("CTRL2"), 52c ("CTRL3") (collectively referred to as "track controllers 52") of the tracks 22a, 22b, 22c of the OBC 12 and their communication arrangements with the controller 20 of the OBC are shown respectively.

[0059] According to an embodiment of the present invention, the rail controller 52 is configured to detect and measure the AC voltage and frequency at the input of the rail 22 of the OBC 12. That is, the rail controller 52a is configured to detect and measure the AC voltage and frequency at the input of the rail 22a; the rail controller 52b is configured to detect and measure the AC voltage and frequency at the input of the rail 22b; and the rail controller 52c is configured to detect and measure the AC voltage and frequency at the input of the rail 22c. (As an alternative, a sawtooth analog signal can be generated and sent directly to the controller 20 instead of having the rail controller count and provide the instantaneous input phase value only digitally upon request of the controller 20. However, this would increase the number of hardware components and the circuit size.)

[0060] In operation, the rail controller 52 transmits this information (i.e., the analog or digital signal sharing) to the general OBC manager MCU (i.e., the controller 20). The controller 20 is also the controller responsible for commanding what the rail controller 52 does. The controller 20 is also responsible for identifying those rails and their corresponding relays that are in the appropriate state for handling power. For such diagnostics, since the phase difference is the only way to typically distinguish L1, L2, and L3 of the OBC 12, it is helpful to know the phase shift of each input phase voltage relative to the other input phase voltages (e.g., helpful to know if the input voltage of rail 22b is offset by 0°, 120°, or some other degree relative to the input voltage of rail 22a; helpful to know if the input voltage of rail 22c is offset by 0°, 120°, or some other degree relative to the input voltages of rail 22a and / or 22b; and so on).

[0061] To this end, each rail controller 52 manages an internal counter that keeps incrementing until the rail controller detects a zero-crossing voltage event of the input voltage of the corresponding rail. When the rail controller 52 detects a zero-crossing voltage event, the rail controller restarts its counter to zero. That is, the rail controller 52a increments its counter until the rail controller 52a detects a zero-crossing voltage event of the input voltage of the rail 22a, at which point the rail controller 52a restarts its counter to zero; the rail controller 52b increments its counter until the rail controller 52b detects a zero-crossing voltage event of the input voltage of the rail 22b, at which point the rail controller 52b restarts its counter to zero; and the rail controller 52c increments its counter until the rail controller 52c detects a zero-crossing voltage event of the input voltage of the rail 22c, at which point the rail controller 52c restarts its counter to zero. In this way, the rail controller 52 acts as a phase detector.

[0062] The controller 20 generates a simultaneous request to all track controllers 52, asking the track controllers to provide their counter values to the controller 20 at a certain moment. The controller 20 processes the counter values to determine what (if any) input voltage phase shift exists between the tracks 22.

[0063] Using the zero-crossing voltage event of the input voltage is one way of synchronous measurement. Other ways include, for example, using peak voltage detection of the input voltage. Generally, any type of threshold detection can be used. That is to say, any means capable of differentiating the input voltages from each other can be used. Therefore, since the amplitudes of the input voltages are the same (or at least substantially the same), any phase differentiating function can be considered at this stage.

[0064] In this article, as an example, "time-voltage" measurement is described. In this case, the controller 20 gives the time (i.e., generates a trigger event), and the track controllers 52 provide their measurements of the input voltage. Based on the comparison of the measured values of the input voltage at the time of triggering, the controller 20 can distinguish the phase difference (if any) between the input voltages.

[0065] As described herein, each track controller 52 generates its measurement of the input voltage from a counter synchronized with the zero-crossing. However, other means of providing a voltage related to the phase difference are possible, such as peak detection or any other threshold voltage detection. Another possibility could be to use a central timer, and then each track controller provides the zero-crossing time to the controller 20, which will evaluate the time difference. Or the second track controller 52b and the third track controller 52c can directly provide the phase difference to the controller 20 based on the time difference between their measurement results and the measurement results from the track controller 52a; and so on.

[0066] Now refer to Figure 4 and continue to refer to Figure 3, shows a first graph 40 and a second graph 44. The first graph 40 has a curve 42 of the AC input voltage of the track 22 provided to the OBC 12. The second graph 44 has a curve 46 of the output of the track controller 52 of the track based on the zero-crossing voltage event of the AC input voltage and a curve 48 of the output of the track controller based on the zero-crossing voltage event timer of the AC input voltage. Each track controller 52 is operable to measure the frequency of the AC grid (i.e., the frequency of the AC input voltage received by the track 22 to which the track controller 52 belongs) by using the zero-crossing voltage event circuit, as shown by curve 46, and / or to determine the time elapsed since the last zero-crossing voltage event (e.g., phase evolution or phase and time evolution, as it is the phase being controlled) by using the zero-crossing voltage event timer (i.e., an internal counter), as shown by curve 48. (In summary, the track controller only has data indicating the occurrence of a zero-crossing. Then the counter increments by a known amount at a given interval (until the next reset).) As described and as illustrated, Figure 4 is an example of a single-phase graph.

[0067] By converting the phase into a voltage value, the main controller 20 can compare the three phase values of the three track circuits 22 with each other to determine the amount of phase shift (if any) between the input voltages received by the track circuits 22 respectively.

[0068] Figure 5A The three-phase graph example based on the unrectified AC input voltage shows a graph corresponding to the Figure 4 graph shown. In particular, Figure 5AShows a first graph 60, a second graph 64, and a third graph 68. The first graph 60 has first curves 62a, 62b, and 62c of an unrectified first-phase AC input voltage, a second-phase AC input voltage, and a third-phase AC input voltage received by a first track 22a, a second track 22b, and a third track 22c. The second graph 64 has first curves 66a, 66b, and 66c of the first track controller 52a, the second track controller 52b, and the third track controller 52c respectively based on zero-crossing voltage event circuit outputs of the first-phase AC input voltage, the second-phase AC input voltage, and the third-phase AC input voltage. The third graph 68 has first curves 70a, 70b, and 70c of the first track controller 52a, the second track controller 52b, and the third track controller 52c respectively based on zero-crossing voltage event timer outputs of the first-phase AC input voltage, the second-phase AC input voltage, and the third-phase AC input voltage. The track controllers 52a, 52b, 52c are operable to measure the frequency of the AC grid (i.e., the frequencies of the first-phase AC input voltage, the second-phase AC input voltage, and the third-phase AC input voltage) by using the zero-crossing voltage event circuit, as shown by curve 64, and / or to determine the time elapsed since the last zero-crossing voltage event by using the zero-crossing voltage event timer (i.e., an internal counter), as shown by curve 68.

[0069] Figure 5B A three-phase graphical example based on a rectified AC input voltage shows graphs corresponding to Figure 4 the graphs shown. (This example with a "rectified" AC input voltage is to describe the situation when the measurements made by the track controllers are after the rectifier stage, which is the first step of each OBC track.) In particular, Figure 5BShows a first graph 80, a second graph 84, and a third graph 88. The first graph 80 has a first curve 82a, a second curve 82b, and a third curve 82c of the rectified first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage. The second graph 84 has a first curve 86a, a second curve 86b, and a third curve 86c output by a first track controller 52a, a second track controller 52b, and a third track controller 52c respectively based on the zero-crossing voltage event circuit of the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage. The third graph 88 has a first curve 90a, a second curve 90b, and a third curve 90c output by a first track controller 52a, a second track controller 52b, and a third track controller 52c respectively based on the zero-crossing voltage event timer of the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage. The track controllers 52a, 52b, 52c are operable to measure the frequency of the AC grid (i.e., the frequency of the first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage) by using the zero-crossing voltage event circuit, as shown in curve 84, and / or to determine the time elapsed since the last zero-crossing voltage event by using the zero-crossing voltage event internal timer (i.e., internal counter), as shown in curve 88.

[0070] Figure 6 Shows a first graph 100, which has a first curve 102a, a second curve 102b, and a third curve 102c output by the zero-crossing voltage event timer of a first track controller 52a, a second track controller 52b, and a third track controller 52c. The zero-crossing voltage event timer output is based on the (unrectified) first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage supplied to the OBC 12 from the three-phase mains power supply 16 when the relays 24a and 24b of the OBC are properly positioned in their open positions (i.e., their reset positions) so that the tracks 22a, 22b, 22c of the OBC are properly connected to the L 1’ 、L 2’ 、L 3’ input terminals.

[0071] Figure 6 Also shows a second graph 104, which has a first curve 106a, a second curve 106b, and a third curve 106c output by the zero-crossing voltage event timer of a first track controller 52a, a second track controller 52b, and a third track controller 52c. The zero-crossing voltage event timer output is based on the situation when the relays 24a and 24b of the OBC are properly positioned in their closed positions so that the tracks 22a, 22b, 22c of the OBC are properly connected to the L of the OBC as a single entity1’ The (unrectified) AC input voltage supplied to the OBC 12 from the single-phase mains power supply 16 at the input terminal.

[0072] Figure 6 A third graph 108 is also shown, which has first curves 110a, second curves 110b, and third curves 110c of the zero-crossing voltage event timer outputs of the first track controller 52a, the second track controller 52b, and the third track controller 52c. The zero-crossing voltage event timer outputs are based on when (i) the first input relay 24a of the OBC is not properly positioned in its closed position so that the second track 22b of the OBC is not properly connected to the first track 22a of the OBC as a single entity to the L 1’ input terminal and (ii) the second input relay 24b of the OBC is properly positioned in its open position so that the third track 22c of the OBC is properly connected separately to the L 3’ The (unrectified) first-phase AC input voltage, second-phase AC input voltage, and third-phase AC input voltage supplied to the OBC 12 from the three-phase mains power supply 16 at the input terminal.

[0073] According to an embodiment of the present invention, the controller 20 uses the information of the first curve, second curve, and third curve of the zero-crossing voltage event timer outputs of the first track controller 52a, the second track controller 52b, and the third track controller 52c (as shown in each of the graphs 100, 104, and 108, for example) to detect the phase configuration of the mains power supply 16 to which the OBC is connected and to diagnose the operating states of the input relays 24a and 24b. The input relays 24a and 24b are used to change the phase (i.e., track) configuration of the OBC to be compatible with whether the mains power supply is polyphase or single-phase.

[0074] In operation, the controller 20 receives voltage values according to the zero-crossing voltage event timer outputs of the track controller 52. As described above, the curves of the zero-crossing voltage event timer outputs shown in each of the graphs 100, 104, and 108 are graphical examples. Using these three possible measurement examples shown in the graphs 100, 104, and 108, the controller 20 will receive the voltage values corresponding to the curves 102a, 102b, and 102c of the graph 100, the voltage values corresponding to the curves 106a, 106b, and 106c of the graph 104, or the voltage values corresponding to the curves 110a, 110b, and 110c of the graph 108. The controller 20 uses the received voltage values to detect the phase difference (if any) between the input voltages of the tracks 22.

[0075] Specifically, the information indicated by the zero-crossing voltage event timers of the first track controller 52a, the second track controller 52b, and the third track controller 52c indicates the time elapsed since the last zero-crossing voltage event on the tracks 22a, 22b, 22c. Using this information, the controller 20 can determine whether the AC input voltages connected to the tracks 22a, 22b, 22c are such that: (i) according to the mains power supply 16 being a three-phase mains power supply, their phases differ from each other by 120° (which is the case represented by the graph 100), and thus the controller can determine that the tracks 22a, 22b, and 22c are operating properly under the three-phase mains power supply; (ii) according to the mains power supply being a single-phase mains power supply, they all have the same phase (which is the case represented by the graph 104), and thus the controller can determine that the tracks 22a, 22b, and 22c are operating properly under the single-phase mains power supply; or (iii) for example, being mixed with two input voltages having the same phase and the remaining input voltage having a different phase (i.e., the remaining input voltage differs in phase from the other two input voltages by 120° or 240°) (which is the case represented by the graph 108), and thus the controller can determine that the tracks 22a and 22c are operating properly under the three-phase mains power supply, but the track 22b is not operating properly under the three-phase mains power supply, and thus identify this situation as a fault. (Of course, in the case of the graph 100, in the case of a three-phase input, any non-120° difference between the phases can be detected and then an anomaly in the provided input voltage signal is indicated. This may also trigger corresponding OBC corrective measures (e.g., disconnection and system stop information due to abnormal input voltage).)

[0076] Considering the graph showing the curves of the zero-crossing voltage event circuit output and the zero-crossing voltage event timer output having the above track controllers, generally, the controller 20 requires a method for detecting the phase difference. One option is to use optocouplers to directly feed the above voltage events to the controller 20. However, this solution is not effective in terms of cost because optocouplers are relatively expensive, and this solution is not effective in terms of CPU load because the controller 20 will have three ports connected to ports with external interrupt capabilities and should handle many interrupts. (There may be two alternative solutions. In the first solution, the controller 20 receives zero-crossing voltage events from all three tracks 22 and then synchronizes three internal timers separately. At the desired moment, the three timers are read and compared. In the second solution, the controller 20 receives sawtooth signals from all three tracks 22 and converts each signal into a digital value at a given time. This will require three analog-to-digital converters (ADCs). In both cases, there are additional electronic components (to generate, isolate, and keep the signals clean up to the controller 20). The timers or ADCs are dedicated resources in the controller 20 with corresponding processing loads.)

[0077] Embodiments of the present invention provide an alternative solution by using a track controller 52 that communicates with a controller 20 and synchronizing measurements of zero-crossing voltage events. In operation, the controller 20 generates simultaneous queries to each of the track controllers 52a, 52b, 52c for the expiration time since the last zero-crossing voltage event. The controller 20 determines what time difference (if any) exists between the expiration times to determine whether the AC input voltage connected to each track is the expected voltage or whether there is a problem with the relay that manages the single-phase / multi-phase configuration of the OBC 12.

[0078] For example, based on the expiration time information provided by the track controllers 52a, 52b, 52c, the controller 20 can determine whether, when the OBC 12 is operating properly while receiving a first-phase AC input voltage, a second-phase AC input voltage, and a third-phase AC input voltage from a three-phase mains power supply, the expiration times differ from each other as expected ( Figure 6 as represented by the graph 100 of ); whether, when the OBC 12 is operating properly while receiving a single-phase AC input voltage from a single-phase mains power supply, the expiration times do not differ from each other as expected ( Figure 6 as represented by the graph 104 of ); whether, when the OBC 12 is not operating properly while receiving a first-phase AC input voltage, a second-phase AC input voltage, and a third-phase AC input voltage from a three-phase mains power supply, when there is a corresponding fault condition, the two expiration times differ from each other and whether the remaining expiration time does not differ from one of the two expiration times as expected ( Figure 6 as represented by the graph 108 of ); and so on.

[0079] As described, according to the algorithm adopted by the OBC 12, the main controller 20 is able to compare the phases of the input voltages received by each track 22 while monitoring the state of the relay 24. The phase shift is verified by the main controller 20 comparing, for example, three sawtooth signals such as Figure 6 as shown. ( Figure 6 The curves shown are graphical examples. The controller 20 receives the voltages corresponding to the curves from the track controller 52. Based on these received voltages and based on knowing the voltage range in the zero-crossing voltage event timer, the controller 20 can calculate the phase difference.) The main controller 20 operates the relay 24 and compares the input voltage signals as a means of verifying the proper operation of the relay 24 before and after charging.

[0080] Now referring to Figure 7A and Figure 7B 、 Figure 7C and Figure 7D, referring to the foregoing drawings, a block diagram of the OBC 12 and a flowchart 110 depicting the operation of the method and system according to an embodiment of the present invention are respectively shown. Figure 7A The block diagram of the OBC 12 in Figure 7A includes a depiction of a first track controller 52a for a first track 22a of the OBC and an nth track controller 52n for an nth track 22n of the OBC. Figure 7B , Figure 7C and Figure 7D The operations shown in the flowchart 110 of Figure 7D include steps where the controller 20 detects the phase configuration of the mains power supply 16 to which the OBC 12 is connected, and include steps where the controller 20 diagnoses the operating state of the input relay 24, which is used to change the phase (i.e., track) configuration of the OBC to be compatible with whether the mains power supply is polyphase or single-phase.

[0081] Note that, as Figure 7A shown, each input relay 24 of the OBC 12 is normally in its open position, in which each track circuit in the associated pair of track circuits 22 can be directly connected individually to the corresponding line of the polyphase mains power supply. Thus, each track circuit in the associated pair of track circuits 22 will receive an input voltage from the polyphase mains power supply. However, if the mains power supply is a single-phase mains power supply, then at least one track circuit in the associated pair of track circuits cannot be directly connected individually to the mains power supply because, being single-phase, the corresponding line will be missing. Therefore, in such a case, at least one track circuit in the associated pair of track circuits will then not receive an input voltage from the mains power supply. The controller 20 can utilize the information provided by the associated track controller to detect this and thus recognize that the mains power supply is a single-phase mains power supply. Then, the controller 20 controls the input relay 24 to move to the closed position, which causes the OBC 12 to conform to a single-track configuration consistent with the mains power supply being single-phase. (This verification is also performed when the relay 24 changes to the open state upon completion of the charging process and is verified in the case of being powered by a single-phase grid to confirm such a change.)

[0082] As described, according to an embodiment of the present invention, the OBC controller at each internal track where a corresponding input voltage signal has been sensed is implemented to utilize an input signal phase detection algorithm that is synchronized by the input voltage crossing zero. The main controller compares the phases at the corresponding tracks and diagnoses the AC grid input and the internal relay system based on the comparison results.

[0083] As described, many OBCs can operate with 1-ph and 3-ph types of power grids. A common approach is to design an OBC with internal tracks that can switch between a multi-phase (i.e., multi-track) configuration and a single-phase (i.e., single-track) configuration via a power switch (i.e., input relay). An intelligent strategy for checking the integrity of the power switch is necessary and is provided by embodiments of the present invention. Embodiments of the present invention implement the integrity check by using software in the OBC digital controller (i.e., track controller) and the MCU (i.e., main controller). Thus, embodiments of the present invention avoid the use of optocouplers that supply the input voltage of the OBC's tracks to the MCU.

[0084] As described, a brief description of embodiments of the present invention includes AC input multi-phase detection and diagnosis, which includes utilizing the input configuration relay of existing hardware. New features of embodiments of the present invention include that, at each OBC track, the AC input phase is converted into a voltage value and sent to the main controller; then, the main controller can distinguish the phase difference and diagnose the internal configuration state of the AC input and the relay. Problems solved by embodiments of the present invention include the diagnosis of the AC input phase including the internal input configuration relay. Embodiments of the present invention provide an improved technique for directly sensing the AC input by the main microcontroller; directly sensing the AC input by the main microcontroller may mean adding a voltage sensing interface including an optocoupler because the main controller (in the 12V domain) must be isolated from the AC input domain.

[0085] In addition, other methods, voltage events, or reference points different from the zero-crossing voltage events described herein can be used to determine the phase shift between the input voltages of the track circuit. For example, peak voltage detection of the input voltage supplied to the track circuit can be used to determine the phase shift between the input voltages.

[0086] Although the exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the present invention. Rather, the words used in this specification are descriptive rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present invention. Additionally, the features of the embodiments of various implementations can be combined to form additional embodiments of the present invention.

Claims

1. An on-vehicle battery charger OBC, comprising: A first track circuit having a first track controller configured to generate a first detection signal based on a voltage event of an input voltage supplied to the first track circuit; A second track circuit having a second track controller configured to generate a second detection signal based on a voltage event of an input voltage supplied to the second track circuit; A relay capable of switching between (i) an open state and (ii) a closed state, in the open state, the relay disconnects the first track circuit and the second track circuit, so that the first track circuit and the second track circuit are configured to receive a first-phase input voltage and a second-phase input voltage from a polyphase mains power supply respectively, and in the closed state, the relay connects the first track circuit and the second track circuit, so that the first track circuit and the second track circuit are configured to both receive the same input voltage from a single-phase mains power supply; And A main controller configured to determine whether the input voltage supplied from the mains power supply to the first track circuit and the input voltage supplied from the mains power supply to the second track circuit are out of phase or in phase based on a comparison of the first detection signal at a given time and the second detection signal at the given time, so as to determine whether the mains power supply is a polyphase mains power supply or a single-phase mains power supply and / or whether the relay is properly or improperly positioned in the open state or the closed state.

2. The OBC according to claim 1, wherein: The voltage events of the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are threshold voltage events.

3. The OBC according to claim 2, wherein: The threshold voltage event is a zero-crossing voltage event or a peak voltage event.

4. The OBC according to claim 1, wherein: The main controller is further configured to pause the operation of at least one of the first track circuit and the second track circuit when the mains power supply is a polyphase mains power supply and the relay is improperly in the closed state and the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase.

5. The OBC according to claim 4, wherein: The main controller is further configured to retry switching the relay from the closed state to the open state when the operation of at least one of the first track circuit and the second track circuit is paused.

6. The OBC according to claim 1, wherein: The main controller is further configured to continue the operation of the first track circuit and the second track circuit when the mains power supply is a single-phase mains power supply and the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase.

7. The OBC according to claim 1, wherein: The main controller is further configured to continue the operations of the first track circuit and the second track circuit when the mains power supply is a polyphase mains power supply and the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are out of phase.

8. The OBC according to claim 1, further comprising: A third track circuit having a third track controller configured to generate a third detection signal based on a voltage event of the input voltage supplied to the third track circuit; A second relay capable of switching between (i) an open state and (ii) a closed state. In the open state of the second relay, the second relay disconnects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to receive a first-phase input voltage and a third-phase input voltage from the polyphase mains power supply respectively. In the closed state of the second relay, the second relay connects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to receive the same input voltage from a single-phase mains power supply; and wherein the main controller is further configured to determine whether the input voltage supplied to the first track circuit from the mains power supply and the input voltage supplied to the third track circuit from the mains power supply are out of phase or in phase according to a comparison of the first detection signal at the given time and the third detection signal at the given time, so as to determine whether the mains power supply is a three-phase mains power supply or a single-phase mains power supply and / or whether the second relay is properly or improperly positioned in the open state or the closed state.

9. The OBC according to claim 8, wherein: The voltage events of the input voltages supplied to the first track circuit, the second track circuit and the third track circuit are zero-crossing voltage events or peak voltage events.

10. The OBC according to claim 8, wherein: The main controller is further configured to pause the operation of at least one of the first track circuit, the second track circuit and the third track circuit when the mains power supply is a three-phase mains power supply and at least one of the relay and the second relay is improperly in the closed state and at least two of the input voltages supplied to the first track circuit, the input voltage supplied to the second track circuit and the input voltage supplied to the third track circuit are in phase.

11. The OBC according to claim 10, wherein: The main controller is further configured to retry switching at least one of the relay and the second relay from the closed state to the open state when the operation of at least one of the first track circuit, the second track circuit and the third track circuit is paused.

12. The OBC according to claim 8, wherein: The main controller is further configured to continue the operations of the first track circuit, the second track circuit, and the third track circuit when the mains power supply is a single-phase mains power supply and the input voltages supplied to the first track circuit, the second track circuit, and the third track circuit are in phase.

13. The OBC according to claim 8, wherein: The main controller is further configured to continue the operations of the first track circuit, the second track circuit, and the third track circuit when the mains power supply is a three-phase mains power supply and the input voltages supplied to the first track circuit, the second track circuit, and the third track circuit are out of phase.

14. A method for use with an on-vehicle battery charger OBC, the on-vehicle battery charger OBC including a first track circuit having a first track controller, a second track circuit having a second track controller, a relay, and a main controller, the relay being capable of switching between (i) an open state and (ii) a closed state, in the open state, the relay disconnects the first track circuit and the second track circuit such that the first track circuit and the second track circuit are configured to receive a first-phase input voltage and a second-phase input voltage from a polyphase mains power supply respectively, in the closed state, the relay connects the first track circuit and the second track circuit such that the first track circuit and the second track circuit are configured to both receive the same input voltage from a single-phase mains power supply, the method comprising: The first track controller generates a first detection signal based on a voltage event of the input voltage supplied to the first track circuit; The second track controller generates a second detection signal based on a voltage event of the input voltage supplied to the second track circuit; and The main controller determines whether the input voltage supplied to the first track circuit from the mains power supply and the input voltage supplied to the second track circuit from the mains power supply are out of phase or in phase according to a comparison of the first detection signal at a given time and the second detection signal at the given time, so as to determine therefrom whether the mains power supply is a polyphase mains power supply or a single-phase mains power supply and / or whether the relay is properly or improperly positioned in the open state or the closed state.

15. The method according to claim 14, wherein: The voltage events of the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are threshold voltage events.

16. The method according to claim 15, wherein: The threshold voltage event is a zero-crossing voltage event or a peak voltage event.

17. The method according to claim 15, further comprising: When the mains power supply is a polyphase mains power supply and the relay is inappropriately in the closed state, and when the input voltage supplied to the first track circuit and the input voltage supplied to the second track circuit are in phase, the main controller pauses the operation of at least one of the first track circuit and the second track circuit.

18. The method according to claim 17, further comprising: When the operation of at least one of the first track circuit and the second track circuit is paused, the main controller retries to switch the relay from the closed state to the open state.

19. The method according to claim 14, wherein The OBC further includes a third track circuit and a second relay. The third track circuit has a third track controller. The second relay is capable of switching between (i) an open state and (ii) a closed state. In the open state of the second relay, the second relay disconnects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to receive a first-phase input voltage and a third-phase input voltage from the polyphase mains power supply respectively. In the closed state of the second relay, the second relay connects the first track circuit and the third track circuit, so that the first track circuit and the third track circuit are configured to both receive the same input voltage from a single-phase mains power supply. The method includes: The third track controller generates a third detection signal based on a voltage event of the input voltage supplied to the third track circuit; and The main controller determines whether the input voltage supplied to the first track circuit from the mains power supply and the input voltage supplied to the third track circuit from the mains power supply are out of phase or in phase according to a comparison of the first detection signal at the given time and the third detection signal at the given time, so as to determine whether the mains power supply is a three-phase mains power supply or a single-phase mains power supply and / or whether the second relay is appropriately or inappropriately positioned in the open state or the closed state.

20. The method according to claim 19, wherein: The voltage events of the input voltages supplied to the first track circuit, the second track circuit and the third track circuit are zero-crossing voltage events or peak voltage events.

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