System and method for protecting an output of a wireless charging device of an electric vehicle

Abstract

Vehicle charging unit (34) comprising a system (10) for protecting an output (40) of a wireless charging device (36), which comprises: a supply line (42) designed to transmit an alternating current induced in a receiving antenna (18); a rectifier (24) designed to convert the alternating current from the supply line (42) into a direct current for charging a vehicle battery (38); a supply line switch (50) connected to the supply line (42) designed to control an electrical connection between the receiving antenna (18) and the rectifier (24); a sensor circuit (48) designed to measure a supply line voltage (V p+ , V p- ) to recognize and a control voltage signal (V low ) using the supply line voltage (V p+ , V p- to generate; and a monitoring circuit (54), wherein the monitoring circuit (54) is designed to react to the control voltage signal (V low ) from the sensor circuit (48) a switch control signal (V g ) to output a signal that causes the supply line switch (50) to change state characterized by a control switch (58), wherein the monitoring circuit (54) is selectively connected to the supply line switch (50) by the control switch (58).

Description

Technical area

[0001] The present disclosure relates to an electric vehicle battery charging protection system. background

[0002] Wireless power transfer systems enable the wireless transmission of energy from a source to a consumer. Inductive power transfer is a non-radiative or near-field type of wireless power transfer. Inductive power transfer uses an oscillating current passing through a primary coil (i.e., a transmitting antenna) of a source to generate an oscillating near-field magnetic field that induces currents in a secondary coil (i.e., a receiving antenna) of a consumer. The source includes an inverter with power transistor switches that operate at controllable times to convert energy from the source into the oscillating current passing through the primary coil.

[0003] Inductive power transfer is used to wirelessly charge a device, such as an electric vehicle's traction battery, using energy from a source. In such wireless electric vehicle charging systems, the source's transmitting antenna is integrated into a charging pad, and the receiving antenna (and an associated rectifier) ​​is installed at a designated location on the vehicle. Inductive power transfer involves inductive coupling between the antennas. For efficient inductive power transfer, the distance between the antennas must be relatively small, within tight tolerances.

[0004] Ideally, the vehicle's receiving antenna should only receive energy transmitted by the transmitting antenna in the charging pad. In practice, the electric vehicle's receiving antenna is an LC resonant circuit that can receive energy from any inductive energy source and transmit it to the traction battery if the signal frequency is close to the receiving antenna's LC resonant frequency. Unexpected energy from stray energy sources can damage the traction battery. Much of the control electronics in a vehicle-side wireless charging device is powered by a low-voltage battery (e.g., a 12-volt battery) only during normal charging. This prevents the control electronics from disconnecting the wireless charging device's output if a near-field magnetic signal from a stray energy source is received.Furthermore, if the low-voltage battery is disconnected from the wireless charging device in any way during normal wireless charging and the control electronics lose power, wireless data transmission between the charging device and the power source is also lost. Without this wireless data transmission with the power source, effective control of the charging process can be lost, potentially damaging the traction battery.

[0005] The generic document DE 10 2014 219 504 A1 discloses a wireless battery charging system with emergency shutdown for a traction battery of an electric vehicle. The generic document DE 20 2015 104 608 U1 discloses an arrangement with a control gear for light sources and a circuit supplied by an inductive element of the control gear with galvanic isolation.

[0006] The object of the invention is to provide an improved vehicle charging unit or an improved method for operating the vehicle charging unit, in particular the charging device of the vehicle charging unit.

[0007] The object of the invention is achieved by a vehicle charging unit according to claim 1 or by a method according to at least one of claims 14 or 17. Overview

[0008] One or more embodiments of the present disclosure relate to a vehicle charging unit comprising a system for protecting an output of a wireless charging device. The vehicle charging unit may include a supply line configured to transmit an alternating current induced in a receiving antenna and a rectifier configured to convert the alternating current from the supply line into a direct current for charging a vehicle battery. The vehicle charging unit may further include a supply line switch, a sensor circuit, a control switch, and a monitoring circuit. The supply line switch may be connected to the supply line and configured to control an electrical connection between the receiving antenna and the rectifier.The sensor circuit can be designed to detect a supply line voltage and generate a control voltage signal using that supply line voltage. The monitoring circuit can be selectively connected to the supply line switch via the control switch. In response to the control voltage signal from the sensor circuit, the monitoring circuit can output a switch control signal that causes the supply line switch to change its state.

[0009] According to one embodiment, the control switch can be a MOSFET. Furthermore, the supply line switch can be an insulated-gate bipolar transistor (IGBT) having a gate that is selectively connected to the monitoring circuit.

[0010] The monitoring circuit can be configured to receive the control voltage signal from the sensor circuit via the receiving antenna during normal wireless charging of the vehicle battery, caused by a current induced in the receiving antenna by a charging base. The control switch can be configured to be normally open during normal wireless charging of the vehicle battery, preventing the switch control signal from the monitoring circuit from reaching the supply line switch. The control switch can be configured to close when the low-voltage battery is disconnected from the monitoring circuit during normal wireless charging. The monitoring circuit can further be configured to wirelessly transmit a deactivation signal to the charging base to shut off an AC power source provided in the charging base.

[0011] The control switch can be configured to be closed when the monitoring circuit is in a sleep mode. The monitoring circuit can be configured to receive energy from the control voltage signal of the sensor circuit when the supply line voltage detected by the sensor circuit is caused by a current induced in the receiving antenna by a stray energy source.

[0012] The supply line switch can be configured to close upon receiving the switch control signal. The supply line can include a positive supply line conductor and a negative supply line conductor. The sensor circuit can be connected to the positive supply line conductor and / or the negative supply line conductor. The supply line switch can include a positive supply line switch and a negative supply line switch, each connected to the positive supply line conductor and the negative supply line conductor, respectively. The positive supply line switch and the negative supply line switch can both be controlled by the same switch control signal from the monitoring circuit. Alternatively, the positive supply line switch and the negative supply line switch can be controlled separately by the monitoring circuit.

[0013] One or more further embodiments of the present disclosure relate to a method for switching off an output of a wireless charging device. The method may involve detecting a stray voltage in a supply line, generated by an alternating current induced by a stray energy source in the supply line; converting the stray voltage in the supply line into a control voltage signal; supplying a monitoring circuit with the control voltage signal; and, in response to receiving energy from the control voltage signal, outputting a switch control signal by the monitoring circuit to a supply line switch, causing the supply line switch to close and discharge the alternating current induced in the supply line to ground.

[0014] The power supply line can be connected to a rectifier to convert alternating current (AC) to direct current (DC) for charging a vehicle battery during normal wireless charging. The step of outputting a switch control signal by the monitoring circuit to a power supply line switch can involve outputting the switch control signal to a negative power supply line switch connected to a positive power supply line conductor, causing the negative power supply line switch to close; or outputting the switch control signal to a positive power supply line switch connected to a negative power supply line conductor, causing the positive power supply line switch to close.

[0015] One or more additional embodiments of the present disclosure relate to a method for switching off an output of a wireless charging device. The method may include converting an alternating current from a supply line into a direct current for charging a vehicle battery, wherein the alternating current in a receiving antenna is induced by a current in a transmitting antenna from an alternating voltage power source in a charging base; generating a control voltage signal at a sensor circuit using a current from the supply line; detecting a loss of energy from a low-voltage battery at a monitoring circuit; and connecting the monitoring circuit to a supply line switch in response to the detection of the loss of energy from the low-voltage battery.and, in response to receiving energy from the control voltage signal, include the output of a switch control signal by the monitoring circuit to the supply line switch, causing the supply line switch to close and discharge the current in the supply line to ground.

[0016] The procedure may further involve the monitoring circuit transmitting a wireless deactivation signal to the charging base in response to the detection of a loss of energy from the low-voltage battery, in order to disconnect the AC power source provided in the charging base. The step of connecting the monitoring circuit to the supply line switch may involve closing a control switch between the supply line switch and the monitoring circuit in response to the detection of a loss of energy from the low-voltage battery.The step of outputting a switch control signal by the monitoring circuit to a supply line switch may involve outputting the switch control signal to a negative supply line switch connected to a positive supply line conductor, causing the negative supply line switch to close; and outputting the switch control signal to a positive supply line switch connected to a negative supply line conductor, causing the positive supply line switch to close. Short description of the drawings Fig. Figure 1 illustrates a schematic representation of an inductive energy transfer system for wirelessly charging an electric vehicle with energy from a charging base; Fig. Figure 2 illustrates a block diagram of an inductive power transfer system; Fig. Figure 3 illustrates a block diagram of a wireless charging device on the vehicle side with a vehicle charging unit according to an embodiment of the present disclosure; Fig. Figure 4 illustrates graphical representations of voltage waveforms of the supply line voltages and a switch control signal of the wireless charging system according to an embodiment of the present disclosure; Fig. Figure 5 illustrates graphical representations of different voltage waveforms on the vehicle side of the wireless charging system according to a further embodiment of the present disclosure; Fig. Figure 6 illustrates a flowchart describing the process of the vehicle charging unit according to an embodiment of the present disclosure; and Fig. Figure 7 illustrates a flowchart describing the process of the vehicle charging unit according to a further embodiment of the present disclosure. Detailed description

[0017] Specific embodiments of the present invention are disclosed herein; however, it is understood that the disclosed embodiments are merely exemplary of the present invention, which can be embodied in various and alternative forms. The figures are not necessarily to scale; some elements may be enlarged or reduced to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis to enable a person skilled in the art to use the present invention in different ways.

[0018] With reference to Fig. Figure 1 shows a schematic representation of a system 10 for inductive power transfer for wirelessly charging an electric vehicle 12 with energy from a charging base 14. The charging base 14 includes a transmitting antenna 16, which is positioned in the ground or on the floor of a structure. Due to its physical design, the transmitting antenna 16 is sometimes referred to as a base plate or mat. The vehicle 12 includes a receiving antenna 18, often referred to as a vehicle plate, which is mounted on the underside of the vehicle. The transmitting antenna 16 and the receiving antenna 18 are aligned in close proximity when the vehicle 12 is properly parked. In this way, energy from the charging base 14 can be transferred from the transmitting antenna 16 to the receiving antenna 18 to charge the vehicle 12. The receiving antenna 18 is connected to the traction battery or similar device of the vehicle 12.The energy wirelessly transferred from the charging base 14 to the vehicle 12 is used to charge the traction / vehicle battery during a normal (i.e., expected) wireless charging session.

[0019] However, when the vehicle 12 is parked and no normal wireless charging is expected, the receiving antenna 18 can still receive electromagnetic energy from sources other than the transmitting antenna 16 of the charging base 14. As shown in Fig. As illustrated in Figure 1, a stray energy source 20 (i.e., an unwanted energy source) located near the vehicle 12 can emit an electromagnetic signal 21. If the frequency of the electromagnetic signal 21 from the stray energy source 20 is close to the resonant frequency of the receiving antenna 18, it can transmit unwanted energy to the receiving antenna 18. Unexpected energy wirelessly transmitted from a stray energy source 20 can damage the traction battery. For example, the stray energy source 20 could be a high-power inverter, a lightning strike, another wireless charging device not designed to charge the vehicle 12, and / or any device that has an electronic component capable of emitting electromagnetic signals.

[0020] With reference to Fig. 2 with ongoing reference to Fig. Figure 1 now shows a block diagram of system 10 for inductive energy transfer. As in Fig. As shown in Figure 2, the charging base 14 of the system 10 for inductive energy transfer includes, in addition to the transmitting antenna 16, an AC power source 22, an AC / DC converter (rectifier) ​​24, a DC / AC converter (inverter) 26, and a resonant network 28. The AC power source 22 supplies the rectifier 24 with AC energy. The rectifier 24 converts the AC energy into DC energy and supplies the inverter 26 with the DC energy. The inverter 26 converts the DC energy into AC energy and supplies the resonant network 28 with the AC energy.

[0021] The transmitting antenna 16 includes one or more coils (i.e., a primary coil 30). The receiving antenna 18 of the vehicle 12 includes one or more coils (i.e., a secondary coil 32). The primary coil 30 and the secondary coil 32 are physically located close to each other (i.e., "loosely coupled") when the vehicle 12 is properly parked. That is, the secondary coil 32 is wirelessly coupled to the primary coil 30 when the secondary coil 32 is in the coupling-mode region of the primary coil 30, thereby providing mutual inductance M and oscillating at essentially the same frequency as the primary coil 30. The AC voltage energy from the inverter 26 passes through the resonant network 28 and through the primary coil 30, causing the primary coil 30 to generate an oscillating near-field magnetic field. The oscillating near-field magnetic field induces currents in the secondary coil 32.The currents in the secondary coil 32 generate alternating voltage energy on the vehicle side. This results in inductive coupling between the primary coil 30 and the secondary coil 32 for inductive energy transfer from the charging base 14 to the vehicle 12.

[0022] As further explained in Fig. As shown in Figure 2, the vehicle 12 can include a vehicle charging unit 34 in addition to the receiving antenna 18. Together, the receiving antenna 18 and the vehicle charging unit 34 can be referred to as a wireless charging device 36. The vehicle charging unit 34 supplies energy to a consumer of the vehicle 12, such as a vehicle battery 38 (i.e., a traction battery).

[0023] Fig. 3 is a block diagram of the vehicle side of the in Fig. Figure 2 illustrates a system for inductive power transfer, which further details the vehicle charging unit 34. As shown, the vehicle charging unit 34 can be connected to the vehicle battery 38 at an output 40 of a wireless charging device. As previously described, the currents induced in the secondary coil 32 of the receiving antenna 18 generate alternating current (AC) energy on the vehicle side. This AC energy is supplied to the vehicle charging unit 34 along a supply line 42. The vehicle charging unit 34 can include a rectifier 44, which converts the AC energy into direct current (DC) energy. The DC energy from the rectifier 44 can be supplied to the vehicle battery 38, for example, through a filter 46. This DC energy at the output 40 of the wireless charging unit charges the vehicle battery 38.

[0024] The supply line 42 can include a positive supply line conductor 42a for receiving the positive output from the receiving antenna 18 and a negative supply line conductor 42b for receiving the negative output from the receiving antenna. Together, the positive supply line conductor 42a and the negative supply line conductor 42b supply the AC voltage energy to the rectifier 44. Accordingly, the positive supply line conductor 42a can carry a positive supply line voltage V during wireless charging. p+ received, and the negative supply line conductor 42b can carry a negative supply line conductor voltage V p- received. The positive supply line conductor voltage V p+ and the negative supply line conductor voltage V p- These are half sine waves that are phase-shifted by about 180 degrees.

[0025] The vehicle charging unit 34 can further include a sensor circuit 48, which is connected to the supply line 42, for detecting a supply line voltage. For example, the sensor circuit 48 can be connected to the positive supply line conductor 42a and / or the negative supply line conductor 42b to detect the output voltage of the receiving antenna. Accordingly, the sensor circuit 48 can detect the positive supply line conductor voltage V p+ and / or the negative supply line conductor voltage V p- The sensor circuit 48 can detect signals output by the receiving antenna 18. Furthermore, the sensor circuit 48 can be configured to provide a low-voltage output, which serves as a control voltage signal V. lowThis is described as generating the output voltage of the receiving antenna using the output voltage detected at the supply line 42. For example, the sensor circuit 48 can be designed to detect either the positive supply line line voltage V p+ or the negative supply line conductor voltage V p- into the control voltage signal V low to convert.

[0026] The vehicle charging unit 34 can also include a supply line switch 50, which is connected to the supply line 42 and is designed to control an electrical connection between the receiving antenna 18 and the rectifier 44. Further with reference to Fig. 3. The supply line switch 50 can include a pair of supply line switches, such as a positive supply line switch 50a and a negative supply line switch 50b. As shown, the positive supply line switch 50a can provide an on / off connection between the negative supply line conductor 42b and ground 52. Similarly, the negative supply line switch 50b can provide an on / off connection between the positive supply line conductor 42a and ground 52. During normal charging, the supply line switches 50a and 50b can be open, and the positive supply line conductor 42a and the negative supply line conductor 42b connect the receiving antenna 18 to the rectifier 44. The output 40 (V outThe supply line to the vehicle battery 38 of the wireless charging device can be switched off by closing the supply line switches 50a and 50b and providing a direct path to ground for the electrical energy in the supply line 42, thereby effectively disconnecting the rectifier 44 from the receiving antenna 18. According to one embodiment, each supply line switch 50 can be an IGBT (insulated gate bipolar transistor), although other types of switches, such as a MOSFET (metal oxide semiconductor field-effect transistor), can be used. The positive supply line switch 50a and the negative supply line switch 50b can be monitored by a monitoring circuit 54 using the control voltage signal V. lowThe monitoring circuit 54 can be part of a main control unit of the vehicle charging unit 34 or can be a dedicated control unit / circuit for controlling the state (i.e., open / closed) of the supply line switches 50 in response to inputs received at the monitoring circuit 54.

[0027] During normal wireless charging, the monitoring circuit 54 can receive power from the receiving antenna 18 via the sensor circuit. Other control components of the vehicle charging unit 34 can receive power from a low-voltage battery 56 (e.g., a 12-volt lead-acid battery) of the vehicle 12. The vehicle charging unit 34 can exchange data with the charging base 14 via near-field communication protocols such as WiFi, Bluetooth, etc., during normal wireless charging, which includes sending wireless data transmission signals to activate / deactivate the AC power source 22. When no normal charging is taking place, the control components of the vehicle charging unit 34 can enter a sleep mode and do not receive power from the low-voltage battery 56.

[0028] The monitoring circuit 54 can be selectively connected to the supply line switches 50 via a control switch 58. The control switch 58 can be controlled by the low-voltage battery 56. The control switch 58 can be open (i.e., off) during normal wireless charging when the low-voltage battery 56 is switched on (i.e., V1). batt (is high), thereby disconnecting the monitoring circuit 54 from the supply line switches 50 (i.e., switches 50a and 50b are off or open). The control switch 58 can be forcibly closed when the low-voltage battery 56 is not present. For example, the control switch 58 can close (i.e., turn on), thereby connecting the monitoring circuit 54 to the supply line switches 50, when the low-voltage battery 56 is switched off (V batt= 0), for example, when no normal wireless charging takes place or when the monitoring circuit loses its connection to the low-voltage battery 56 during normal wireless charging. In both cases, the sensor circuit 48 can send the control voltage signal V to the monitoring circuit 54. low supply. Under certain conditions, the control voltage signal V low This can be used to control the supply line switches 50 when the low-voltage battery 56 is not present. According to one embodiment, the control switch 58 can be a MOSFET.

[0029] As previously described, the receiving antenna 18 can receive electromagnetic signals 21 from unwanted sources, such as the stray energy source 20. In such a case, the alternating current induced in the receiving antenna 18 due to the unwanted electromagnetic field can be rectified and charged into the vehicle battery 38 via the supply line 42, potentially causing damage to the battery and high-power electronics. To prevent damage, the output 40 of the wireless charging device to the vehicle battery 38 can be switched off by closing the supply line switches 50a and 50b and providing a direct path to ground for the electrical energy in the supply line 42, effectively disconnecting the rectifier 44 from the receiving antenna 18.

[0030] In this way, when an unwanted charging event occurs, the sensor circuit 48 can detect a supply line voltage generated by the stray energy source 20 and convert the supply line voltage into a low-voltage output (i.e., a control voltage signal V). low ) which can be supplied to the monitoring circuit 54. Accordingly, the unwanted electrical energy in the supply line 42, when the control switch 58 is closed, can be used to supply the monitoring circuit 54 so that it can generate a switch control signal V. g can supply a signal that closes the supply line switches 50 and switches off the output 40 of the wireless charging device. The switch control signal V g can be triggered when the control voltage signal V low a voltage threshold has been reached. Alternatively, the switch control signal V g In IGBT switches, the control voltage signal Vlow The monitoring circuit 54 can be used to track and cause the supply line switches 50 to close when the gate voltage exceeds a threshold value of the IGBT switches, thus providing a path to ground between the collector and the probe. This allows the output 40 of the wireless charging device to be quickly and effectively switched off to protect the vehicle battery 38 from damage due to an unwanted AC current generated by the receiving antenna 18. The monitoring circuit 54 can monitor the same switch control signal V. g Use to control both the positive supply line switch 50a and the negative supply line switch 50b. Alternatively, the monitoring circuit 54 can output different switch control signals to the positive supply line switch 50a and the negative supply line switch 50b to control them separately.

[0031] As previously described, the monitoring circuit 54 can supply energy via the control voltage signal V during a normal wireless charging process. lowThe sensor circuit 48 receives data from the receiving antenna 18. If the low-voltage battery 56 is disconnected from the vehicle charging unit 34 during normal charging, the vehicle charging unit 34 may be unable to exchange data with the charging base 14 to terminate the charging process. Without wireless data transmission, proper control of the charging process may be lost, potentially causing damage to the vehicle battery 38. To prevent this, the monitoring circuit 54 may also be configured to open (close) the supply line switches 50 in response to the loss of the low-voltage battery 56, thus providing a path to ground for the electrical energy in the supply line 42, effectively disconnecting the rectifier 44 from the receiving antenna 18.If the low-voltage battery 56 is lost during normal wireless charging, the control switch 58 closes and allows the control voltage signal V. low The signal generated by the sensor circuit 48 using the supply line voltage controls the supply line switches 50 via the monitoring circuit 54. That is, when the control switch 58 is closed, the monitoring circuit 54 can receive the switch control signal V. g supply to the supply line switches 50, causing them to close. The monitoring circuit 54 can also transmit a wireless deactivation signal to the charging base 14, instructing the charging base 14 to switch off the AC power source 22.

[0032] Fig. Figure 4 illustrates timing diagrams that graphically represent an example of different voltage waveforms of the wireless charging system when the vehicle charging unit 34 receives energy from a stray energy source 20. The graphic representation 400A illustrates the waveform of the voltage V. batt The low-voltage battery is depleted when the wireless charging device is not in operation to charge the vehicle battery 38. As shown, the voltage of the low-voltage battery is zero volts. Accordingly, the control switch 58 can be on (i.e., closed).

[0033] Graphic 400 B illustrates the waveforms of the positive supply line voltage V p+ and the negative supply line voltage V p- joined together. The solid line represents the positive supply line voltage V. p+ on, while the dashed line represents the negative supply line voltage V p-This indicates that at time t1, the receiving antenna 18 can receive electromagnetic signals 21 from a source other than the transmitting antenna 16, such as the stray energy source 20, and begins to generate currents in the supply line 42. For example, a negative supply line voltage V p- The negative supply line voltage V occurs at t1 on the negative supply line conductor 42b. The sensor circuit 48 can measure the negative supply line voltage V. p- detect and the control voltage signal V low generated using the supply line voltage. The control voltage signal V low The monitoring circuit 54 can be supplied by the sensor circuit 48.

[0034] As illustrated in graphical representation 400C, the monitoring circuit 54 can react to the reception of the control voltage signal V low starting at approximately t1, a switch control signal V gto generate. It is noted that at t1 the switch control signal V g below the threshold voltage V th the supply line switch 50 may be faulty and therefore unable to close the supply line switch 50 to effectively disconnect the supply line 42 from the rectifier 44. The voltage of the switch control signal V g can continue to rise while the stray energy source 20 continues to induce an unwanted current in the receiving antenna 18. At time t2, the switch control signal V g be strong enough to close the supply line switches 50, (e.g. the threshold voltage V) th(exceed at the gate of the IGBT). When the supply line switches are closed, the supply line conductors 42 are grounded at approximately t2. Therefore, the vehicle battery 38 can be effectively disconnected from the receiving antenna 18 and thus protected from unwanted energy from the stray energy source 20. The graphic 400D illustrates the output voltage V. out at output 40 of the wireless charging device. If a stray voltage occurs in the supply line 42, the output voltage V may change. out until t2 rises, at which point the vehicle battery 38 is effectively disconnected from the receiving antenna 18.

[0035] Fig. Figure 5 illustrates timing diagrams that graphically represent various voltage waveforms on the vehicle side of the wireless charging system according to a further embodiment of the present disclosure. Graphical representation 500A illustrates the waveforms of the positive supply line voltage V. p+ and the negative supply line voltage V p- connected while the vehicle battery 38 is being charged in a normal charging process. The solid line indicates the positive supply line voltage V. p+ on, while the dashed line represents the negative supply line voltage V p- specifies. For example, the supply line voltages V p+ and V p- Both are half-sine waves, phase-shifted by approximately 180 degrees. Graphic 500B illustrates the waveform of the voltage V. battthe low-voltage battery. During normal operation, the low-voltage battery delivers 56 (in Fig. 3) the voltage V batt The low-voltage battery is connected to the vehicle charging unit 34 to supply the control electronics. As shown at time t3, the voltage V can battThe voltage of the low-voltage battery drops to approximately zero volts, indicating that the low-voltage battery 56 is disconnected from the vehicle charging unit 34. When it loses power from the low-voltage battery 56, the vehicle charging unit 34 is unable to exchange data with the charging base 14. To protect the vehicle battery 38 when this occurs, the monitoring circuit 54 can be configured to disconnect the output 40 of the wireless charging unit by closing the supply line switches 50. For example, when power is lost from the low-voltage battery 56, an on-board electrical system (not shown) can maintain its output voltage for a period of time (e.g., approximately 50 milliseconds). During this period, the vehicle charging unit 34 can send a wireless data transmission to the charging base 14, instructing the AC power source 22 to cease supplying power.After the on-board voltage has dropped to zero, the control switch 58 can be turned on (i.e., closed), thereby activating the monitoring circuit 54 in response to the control voltage signal V. low The sensor circuit 48 enables the control of the supply line switches 50. Based on the control voltage signal, the monitoring circuit 54 can output the switch control signal V. g As illustrated in diagram 500C, the current is output to the supply line switches 50 to close (turn on) the switches that effectively ground the supply line 42. Accordingly, the current induced in the receiving antenna 18 can be discharged to ground 52 via the supply line switches 50.

[0036] Fig. Figure 6 is a flowchart illustrating process 600 for switching off an output of a wireless charging device when stray energy is detected. In process 602, the sensor circuit 48 of the vehicle charging unit 34 can detect an unwanted voltage in the supply line 42, which is generated by a current induced by a stray energy source 20 in the supply line. The unwanted voltage from the stray energy source 20 can be detected when the vehicle charging unit 34 is in a sleep mode (i.e., when the vehicle battery 38 is not being intentionally charged). In process 604, the sensor circuit 48 can convert the unwanted voltage in the supply line 42 into a low-voltage output (i.e., a control voltage signal V). low ) convert. The control voltage signal V lowcan be supplied to the monitoring circuit 54 to power the monitoring circuit 54, as provided in procedure 606. In procedure 608, the monitoring circuit 54 can be powered in response to receiving energy from the control voltage signal V. low a switch control signal V g output to a supply line switch 50. For example, the monitoring circuit 54 can output the switch control signal V g Output both to the negative supply line switch 50b, which is connected to the positive supply line conductor 42a, and to the positive supply line switch 50a, which is connected to the negative supply line conductor 42b. The switch control signal V g can cause the supply line switches 50 to close and discharge the alternating current induced in the supply line 42 to ground, thereby effectively switching off the output 40 of the wireless charging device.

[0037] Fig. Figure 7 is a flowchart illustrating process 700 for switching off the output 40 of the wireless charging device when the low-voltage battery 56 is disconnected from the vehicle charging unit 34 during normal wireless charging. During normal wireless charging, the AC power source 22 in the charging base 14 of the transmitting antenna 16 can supply a current to induce an AC current in the receiving antenna 18, which is then supplied to the supply line 42. In process 702, the AC current in the supply line 42 can be converted into a DC current to charge the vehicle battery 38. In process 704, the sensor circuit 48 can detect the control voltage signal V. lowusing power from the supply line 42. During normal wireless charging, the control switch 58 between the supply line switches 50 and the monitoring circuit 54 can be open, thereby transmitting the switch control signal V. g The monitoring circuit 54 blocks the charging process. The vehicle charging unit 34 may require energy from the low-voltage battery 56 to control the charging process. In process 706, the vehicle charging unit 34 can detect a loss of energy from the low-voltage battery 56. Upon detection of the loss of energy from the low-voltage battery 56, the control switch 58 can be closed, and the monitoring circuit 54 can use the control voltage signal V to close the supply line switches 50. lowcontrol, as provided for in procedure 708. In addition, the vehicle charging unit 34 (e.g. the monitoring circuit 54) can transmit a wireless deactivation signal to the charging base 14 in procedure 710 to switch off the AC power source 22 in the charging base.

[0038] In process 712, the monitoring circuit 54 can react to receiving energy from the control voltage signal V. low a switch control signal V g output to a supply line switch 50. For example, the monitoring circuit 54 can output the switch control signal V g Output both to the negative supply line switch 50b, which is connected to the positive supply line conductor 42a, and to the positive supply line switch 50a, which is connected to the negative supply line conductor 42b. The switch control signal V gcan cause the supply line switches to close and discharge the alternating current induced in the supply line 42 to ground, thereby effectively switching off the output 40 of the wireless charging device.

Claims

[1] A vehicle charging unit (34) comprising a system (10) for protecting an output (40) of a wireless charging device (36) comprising: a supply line (42) configured to transmit an alternating current induced in a receiving antenna (18); a rectifier (24) designed to convert the alternating current from the supply line (42) into a direct current for charging a vehicle battery (38); a supply line switch (50) connected to the supply line (42) and configured to control an electrical connection between the receiving antenna (18) and the rectifier (24); a sensor circuit (48) configured to sense a supply line voltage (V p+ , V p- ) and a control voltage signal (V low ) using the supply line voltage (V p+ , V p- ) and a monitoring circuit (54), wherein the monitoring circuit (54) is designed to, in response to the control voltage signal (V low ) from the sensor circuit (48) a switch control signal (V g ) which causes the supply line switch (50) to change a state characterized by a control switch (58), wherein the monitoring circuit (54) is selectively connected to the supply line switch (50) by the control switch (58). [2] The vehicle charging unit of claim 1, wherein the control switch (58) is a MOSFET. [3] The vehicle charging unit of claim 1 or 2, wherein the supply line switch (50) comprises an insulated gate bipolar transistor (IGBT) having a gate selectively connected to the monitoring circuit (54). [4] Vehicle charging unit according to claim 1, 2 or 3, wherein the monitoring circuit (54) is designed to be dependent on the control voltage signal (V low ) of the sensor circuit (48) by the receiving antenna (18) during normal wireless charging of the vehicle battery (38) caused by a current induced in the receiving antenna (18) by a charging base (14). [5] A vehicle charging unit according to any one of the preceding claims, wherein the control switch (58) is designed to be normally open during normal wireless charging of the vehicle battery (38) and to prevent the switch control signal (V g ) from the monitoring circuit (54) reaches the supply line switch (50). [6] A vehicle charging unit according to any one of the preceding claims, wherein the control switch (58) is configured to close when a low voltage battery (56) is disconnected from the monitoring circuit (54) during normal wireless charging. [7] The vehicle charging unit of claim 4, 5 or 6, wherein the monitoring circuit (54) is further configured to wirelessly transmit a deactivation signal to the charging base (14) to turn off an AC power source (22) provided in the charging base (14). [8] A vehicle charging unit according to any one of the preceding claims, wherein the control switch (58) is designed to be closed when the monitoring circuit (54) is in a sleep mode. [9] Vehicle charging unit according to one of the preceding claims, wherein the monitoring circuit (54) is designed to detect reserve energy from the control voltage signal (V low) of the sensor circuit (48) when the supply line voltage (V p+ , V p- ) is caused by a current induced by a stray energy source (20) in the receiving antenna (18). [10] Vehicle charging unit according to one of the preceding claims, wherein the supply line switch (50) is designed, upon receiving the switch control signal (V g ) to be closed. [11] Vehicle charging unit according to one of the preceding claims, wherein the supply line (42) includes a positive supply line conductor (42a) and a negative supply line conductor (42b), the sensor circuit (48) is connected to the positive supply line conductor (42a) and / or the negative supply line conductor (42b), and the supply line switch (50) includes a positive supply line switch (50a) and a negative supply line switch (50b) which are respectively connected to the positive supply line conductor (42a) and the negative supply line conductor (42b). [12] Vehicle charging unit according to claim 11, wherein the positive supply line switch (50a) and the negative supply line switch (50b) are both controlled by the same switch control signal (V g ) are controlled by the monitoring circuit (54). [13] A vehicle charging unit according to claim 11, wherein the positive supply line switch (50a) and the negative supply line switch (50b) are separately controlled by the monitoring circuit (54). [14] A method for switching off an output (40) of a wireless charging device (36), comprising: Detecting a stray voltage in a supply line (42) generated by an alternating current induced in the supply line (42) by a stray energy source (20); Converting the stray voltage in the supply line (42) into a control voltage signal (V low ); Supplying a monitoring circuit (54) using the control voltage signal (V low ); and characterized by in response to receiving energy from the control voltage signal (V low ) Outputting a switch control signal (V g ) through the monitoring circuit (54) to a supply line switch (50), causing the supply line switch (50) to close and discharge the alternating current induced in the supply line (42) to ground (52). [15] The method of claim 14, wherein the supply line (42) is connected to a rectifier (24) for converting an alternating current into a direct current for charging a vehicle battery (38) during normal wireless charging. [16] Method according to claim 14 or 15, wherein the outputting of a switch control signal (V g ) through the monitoring circuit (54) to a supply line switch (50): Outputting the switch control signal (V g ) to a negative supply line switch (50b) connected to a positive supply line conductor (42a), thereby causing the negative supply line switch (50b) to close; and Outputting the switch control signal (V g) to a positive supply line switch (50a) connected to a negative supply line conductor (42b), thereby causing the positive supply line switch (50a) to close. [17] A method for switching off an output (40) of a wireless charging device (36), comprising: Converting an alternating current from a supply line (42) into a direct current for charging a vehicle battery (38), wherein the alternating current is induced in a receiving antenna (18) by a current in a transmitting antenna (16) from an alternating voltage power source (22) in a charging base (14); Generating a control voltage signal (V low ) to a sensor circuit (48) using a current from the supply line (42); characterized by Detecting a loss of energy from a low voltage battery (56) at a monitoring circuit (54); Connecting the monitoring circuit (54) to a supply line switch (50) in response to detecting the loss of power from the low voltage battery (56); and in response to receiving energy from the control voltage signal (V low ) Outputting a switch control signal (V g ) through the monitoring circuit (54) to the supply line switch (50), causing the supply line switch (50) to close and divert the current in the supply line (42) to ground (52). [18] The method of claim 17, further comprising: Transmitting a wireless deactivation signal by the monitoring circuit (54) to the charging base (14) in response to detecting the loss of power from the low voltage battery (56) to turn off the AC power source (22) provided in the charging base (14). [19] The method of claim 17 or 18, wherein connecting the monitoring circuit (54) to the supply line switch (50) comprises: Closing a control switch (58) between the supply line switch (50) and the monitoring circuit (54) in response to detecting the loss of energy from the low voltage battery (56). [20] A method according to claim 17, 18 or 19, wherein outputting a switch control signal (V g ) through the monitoring circuit (54) to a supply line switch (50): Outputting the switch control signal (V g ) to a negative supply line switch (50b) connected to a positive supply line conductor (42a), thereby causing the negative supply line switch (50b) to close; and Outputting the switch control signal (V g) to a positive supply line switch (50a) connected to a negative supply line conductor (42b), thereby causing the positive supply line switch (50a) to close.

Images