Method and system for testing a protection mechanism against over voltage at a vehicle assembly

Abstract

A circuitry for testing a protection mechanism against an overvoltage event at a vehicle assembly 120 of a vehicle having at least one motor for electric propulsion, said vehicle assembly associated w

Description

[0001] The present invention relates generally to wireless power transmission in electric vehicles and more specifically to protecting the receiver of electric vehicle from over voltage. BACKGROUND OF THE INVENTION

[0002] Prior to setting forth the background of the invention, it would be advantageous to provide some term definitions as follows:

[0003] The term ‘electric vehicle’ refers generally to a vehicle powered solely, or in part, by electrical energy stored (e.g., chemically) in a battery, or the like. In the present context, an ‘electric vehicle’ operates as part of a wireless power transfer (WPT) system and has provision for receiving (e.g., at coils disposed on the underside of the vehicle) a wirelessly induced electromotive force (i.e., voltage) that may be stored, or otherwise utilized to recharge the battery. For an electromagnetically induced voltage to occur, the vehicle (i.e., the ‘conductor’) may be moving relative to a magnetic field which is, for example, projected about the road upon which the vehicle is travelling. Alternatively, the magnetic field may be periodically varied (e.g., through use of alternating current) thereby inducing a voltage at the vehicle in its static form.

[0004] The term ‘ground assembly” refers generally to a portion of, for example, a road, a highway or motorway which has been modified to comprise a medium for wirelessly transmitting power (i.e., a ‘power transmitter’). This may mean that the road comprises a plurality of coils embedded beneath the surface of the road section which are operable to emit a magnetic field. In typical arrangements, the medium (coils) may be connected to an alternating current source, e.g. an electrical grid, and may generate a varying magnetic field, thereby inducing a voltage in any proximate conductor.

[0005] The term ‘vehicle assembly” refers generally to circuitry on board of the electric vehicle which include a receiver to receive the power transmitted from the ground assembly, an energy regulator, as well as other circuitries as needed to ensure the battery of the electric vehicle and then the motor of the electric vehicle receive the energy per their requirements.

[0006] Charging the battery of the electric vehicle either while the electric vehicle is static when the vehicle is parked or dynamic when the vehicle is moving may involve incidents of overvoltage which may cause several safety issues and may damage the battery and the motor.

[0007] These undesirable overvoltage incidents may occur whenever the voltage across the output of the vehicle assembly goes beyond an acceptable voltage level or alternatively, whenever the gradient of the voltage increase level at the output of the vehicle assembly goes beyond an acceptable gradient level. SUMMARY OF THE PRESENT INVENTION

[0008] The present invention addresses the need to carry out a built-in test for a mechanism configured to protect against undesirable overvoltage events in a vehicle assembly of an electric vehicle operating as a part of a wireless power transfer system. This is done by forcing some or all of the components of the protection mechanism to operate by triggering it to operational mode even without overvoltage incident occurring. The triggering may be carried out using a dedicated testing circuitry which may be controlled by a microcontroller on the vehicle assembly.

[0009] Embodiments of the present invention provide a circuitry for testing a protection mechanism against an overvoltage event at a vehicle assembly of a vehicle having at least one motor for electric propulsion, wherein the vehicle assembly is associated with a ground assembly as a part of a wireless power transfer system for electric vehicles, wherein the protection mechanism may include a controlled switch to divert current off the output of the vehicle assembly, into a by-pass circuitry, upon detection of the overvoltage event across the output of the vehicle assembly. The circuitry for testing may include: a voltage or current source configured to apply an electrical charge into a gate of the controlled switch at a level which is sufficient to turn the controlled switch on, so as to verify that the controlled switch and the by-pass circuitry serve as a shortcut of the output of the vehicle assembly.

[0010] These and other advantages of the present invention are set forth in detail in the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a better understanding of the invention and in order to show how it may be implemented, references are made, purely by way of example, to the accompanying drawings in which, like-numerals designate corresponding elements or sections. In the accompanying drawings:

[0012] Figure 1 is a block diagram in accordance with some embodiments of the present invention;

[0013] Figure 2 is a block diagram in accordance with some embodiments of the present invention;

[0014] Figure 3 is a block diagram in accordance with some embodiments of the present invention; and

[0015] Figure 4 is a block diagram in accordance with some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] With specific reference now to the drawings in detail, it is stressed that the particulars shown are for the purpose of example and solely for discussing the preferred embodiments of the present invention and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention. The description taken with the drawings makes apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0017] Before explaining the embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following descriptions or illustrated in the drawings. The invention is applicable to other embodiments and may be practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0018] According to some embodiments of the present invention the vehicle assembly which charges the battery in the vehicle acts as current source. As opposed to a voltage source which can be disconnected using a simple series circuit breaker, the current source can be disabled by a shortcut.

[0019] These are the situations that require disabling the output of the vehicle assembly: a) The receiver is not connected to the load, the output connector is not connected. b) The vehicle initiates disconnection for any reason. c) A malfunction while working that disconnects the receiver from the battery.

[0020] In all these situations the current source tries to continue the current and since it does not see a load, the voltage will rise. The outcome may lead eventually to a destruction of the vehicle assembly circuitry.

[0021] Embodiments of the present invention have been designed to operate under the following conditions: a) Power transmission at a working frequency of at least 85kHz b) Currents flowing though the vehicle assembly of up to 150A c) Fast response time of less than 0. ImS for disconnecting the ground assembly. d) Working voltage of 1000V

[0022] Figure 1 is a block diagram of a vehicle assembly 120 with an overvoltage protection circuitry according to some embodiments of the present invention designed to address an overvoltage event in accordance with the aforementioned conditions. Ground assembly 110 may include a ground assembly power circuitry 112 which is controlled by ground assembly controller 113 and may be configured to feed transmitter coils 111 with the electrical power required to create the magnetic needed for the wireless power transfer with vehicle assembly 120 as part of a wireless power transfer system 100.

[0023] According to some embodiments of the present invention, vehicle assembly 120 may be placed on board an electric vehicle (not shown) and may include receiver coils 121 which may be coupled to transmitter coils 111. Receiver coils 121 may feed the input of a rectifier 122 configured to rectify the alternating current into direct current. Rectifier 122 in turn feeds the input of a direct current (DC) filter 123 which reduces the harmonies of the power signal passing through it. The output of DC filter 123 is also effectively the output of vehicle assembly 120 which may feed the EV battery 130 or a capacitor which in turn feeds the motor (not shown) of the EV.

[0024] According to some embodiments of the present invention, detection circuitry 124 may receive as an input, the voltage across the output of vehicle assembly 120 and the output of detection circuitry 124 may be connected to a vehicle assembly controller 127.

[0025] The input of controlled switch circuitry 125 is connected to the output of vehicle assembly 120 and the output of controlled switch circuitry 125 is connected to an input of a bypass circuitry 126.

[0026] According to some embodiments of the present invention, one of the outputs of vehicle assembly controller 127 is connected to a control input of the controlled switch circuitry.

[0027] According to some embodiments of the present invention, vehicle assembly may further include a controllable current source 129 which may be controlled by a testing circuitry 128 which in turn may be controlled by vehicle assembly controller 127. The output of current source 129 may be connected to the gate of controlled switch circuitry 125.

[0028] In operation, ground assembly transmits energy via transmitter coils 111 to receiver coils 121 usually on demand possibly in accordance with a communication between vehicle assembly 120 and ground assembly 110.

[0029] Vehicle assembly 120 further includes an RF transmitter 128 which is controlled by vehicle assembly controller 127 and is also fed by modulator (not shown) which may be controlled in turn by vehicle assembly controller 127.

[0030] In operation, when charging is needed, either static or dynamic, vehicle assembly controller 127 instructs RF transmitter to transmit a power request signal to RF receiver 114 of ground assembly 110. The power request signal is a modulated signal such that the modulating signal is a series of pulses where the duty cycle of the pulse may indicate the level of power needed and the carrier signal is an RF signal, so the modulated signal is a pulsed RF signal. The modulating signal may also include a unique identification of the EV associated with vehicle assembly 120. On the ground assembly 110 side, RF receiver 114 receives and demodulate the modulate signal and ground assembly controller 113 may be configured to set ground assembly power circuitry 112 accordingly so that the power applied by ground assembly power circuitry 112 to transmitter coils 111 match the power request signal initiated by vehicle assembly controller 127 and transmitted by RF transmitter 128.

[0031] The communication between vehicle assembly 120 and ground assembly 110 is unidirectional in nature and may issue power requests but is not receiving any communication from ground assembly 110.

[0032] According to some embodiments of the present invention, RF transmitter 12 at the vehicle assembly 120 repeatedly transmits a power request signal to the ground assembly, wherein the power request signal is a modulated signal wherein the modulating signal comprises a unique identifier of the electric vehicle.

[0033] According to some embodiments of the present invention, detection circuitry 124 is configured to detect an overvoltage event across the output of vehicle assembly 120. An overvoltage event may occur whenever voltage level across an output of the vehicle assembly goes beyond a specific level, or when the voltage gradient across an output of the vehicle assembly goes beyond a specific voltage gradient.

[0034] According to some embodiments of the present invention, controlled switch circuitry 125 diverts current off the output of the vehicle assembly 120, into by-pass circuitry 126, upon detection of an overvoltage event by detection circuitry 124 across the output of the vehicle assembly.

[0035] According to some embodiments of the present invention, controlled switch circuitry may be operated directly by detection circuitry 124 or via vehicle assembly controller 127.

[0036] According to some embodiments of the present invention, bypass circuitry 126 may be implemented as a rectifier having two sets positive-side diodes and negative-side diodes and once an overvoltage event has been detected by detection circuitry 124 the switch in controlled switch circuitry 125 divert the current from output of vehicle assembly 120 into the rectifier having two sets positive-side diodes and negative-side diodes which is in turn grounded to earth.

[0037] According to some embodiments of the present invention, controlled switch circuitry 126 may include a silicon-controlled rectifier (SCR). The controlled switch can also be implemented as a power metal-oxide-semiconductor field-effect transistor (MOSFET) or insulated-gate bipolar transistor (IGBT) and bypass circuitry 126 may be implemented one or more sets of power diodes connected in series to the ground.

[0038] According to some embodiments of the present invention, in various points of time when it is desirable to verify the correct operation of controlled switch circuitry 125 specifically whenever an overvoltage event has not been detected by detection circuitry 124, current source 129 may generate a current at a level sufficient to activate the gate of controlled switch circuitry 125 and thus verify that controlled switch circuitry 125 is effectively a switch. This can be achieved by testing circuitry 128 controlling a current source 129 to inject such a current into the gate of controlled switch circuitry 125 and measure the current level flowing as in indication that the gate has been opened.

[0039] Advantageously in this embodiment, testing circuitry 128 implements a built-in test of controlled switch circuitry 125 without applying overvoltage across the output of vehicle assembly. This check can be carried out periodically while EV is operating and also prior to charging and during charging is predefined intervals.

[0040] Figure 2 is a block diagram of a vehicle assembly 220 with an overvoltage protection circuitry according to some embodiments of the present invention designed to address an overvoltage event in accordance with the aforementioned conditions. Ground assembly 110 may include a ground assembly power circuitry 112 which is controlled by ground assembly controller 113 and may be configured to feed transmitter coils 111 with the electrical power required to create the magnetic needed for the wireless power transfer with vehicle assembly 220 as part of a wireless power transfer system 200.

[0041] According to some embodiments of the present invention, vehicle assembly 220 may be placed on board an electric vehicle (not shown) and may include receiver coils 121 which may be coupled to transmitter coils 111. Receiver coils 121 may feed the input of a rectifier 122 configured to rectify the alternating current into direct current. Rectifier 122 in turn feeds the input of a direct current (DC) filter 123 which reduces the harmonies of the power signal passing through it. The output of DC filter 123 is also effectively the output of vehicle assembly 220 which may feed the EV battery 130 or a capacitor which in turn feeds the motor (not shown) of the EV.

[0042] According to some embodiments of the present invention, detection circuitry 124 may receive as an input, the voltage across the output of vehicle assembly 220 and the output of detection circuitry 124 may be connected to a vehicle assembly controller 127.

[0043] The input of controlled switch circuitry 125 is connected to the output of vehicle assembly 220 and the output of controlled switch circuitry 125 is connected to an input of a bypass circuitry 126.

[0044] According to some embodiments of the present invention, one of the outputs of vehicle assembly controller 127 is connected to a control input of the controlled switch circuitry.

[0045] According to some embodiments of the present invention, vehicle assembly may further include a controllable current source 129 which may be controlled by a testing circuitry 128 which in turn may be controlled by vehicle assembly controller 127. The output of current source 129 may be connected to the gate of controlled switch circuitry 125.

[0046] In operation, ground assembly transmits energy via transmitter coils 111 to receiver coils 121 usually on demand possibly in accordance with a communication between vehicle assembly 220 and ground assembly 110 which is beyond the scope of embodiments of the present invention.

[0047] According to some embodiments of the present invention, detection circuitry 124 is configured to detect an overvoltage event across the output of vehicle assembly 220. An overvoltage event may occur whenever voltage level across an output of the vehicle assembly goes beyond a specific level, or when the voltage gradient across an output of the vehicle assembly goes beyond a specific voltage gradient.

[0048] According to some embodiments of the present invention, controlled switch circuitry 125 diverts current off the output of the vehicle assembly 220, into by-pass circuitry 126, upon detection of an overvoltage event by detection circuitry 124 across the output of the vehicle assembly.

[0049] According to some embodiments of the present invention, controlled switch circuitry may be operated directly by detection circuitry 124 or via vehicle assembly controller 127.

[0050] According to some embodiments of the present invention, bypass circuitry 126 may be implemented as a rectifier having two sets positive-side diodes and negative-side diodes and once an overvoltage event has been detected by detection circuitry 124 the switch in controlled switch circuitry 125 divert the current from output of vehicle assembly 120 into the rectifier having two sets positive-side diodes and negative-side diodes which is in turn grounded to earth.

[0051] According to some embodiments of the present invention, controlled switch circuitry 126 may include a silicon-controlled rectifier (SCR). The controlled switch can also be implemented as a power metal-oxide-semiconductor field-effect transistor (MOSFET) or insulated-gate bipolar transistor (IGBT) and bypass circuitry 126 may be implemented one or more sets of power diodes connected in series to the ground.

[0052] According to some embodiments of the present invention, in various points of time when it is desirable to verify the correct operation of controlled switch circuitry 125 specifically whenever an overvoltage event has not been detected by detection circuitry 124, current source 129 may generate a current at a level sufficient to activate the gate of controlled switch circuitry 125 and thus verify that controlled switch circuitry 125 is effectively a switch. This can be achieved by testing circuitry 128 controlling a current source 129 to inject such a current into the gate of controlled switch circuitry 125 and measure the current level flowing as in indication that the gate has been opened.

[0053] According to some embodiments of the present invention, vehicle assembly may further include a peak-current suppressor 124 connected between the output of DC filter 123 (being the output of vehicle assembly 220) and between the gate of controlled switch circuitry 125. peak-current suppressor 124 may further be connected and fed by controlled current source 129.

[0054] According to some embodiments of the present invention, peak-current suppressor 124 may include one or more electrical elements that prevent or delay the flow of an electrical current coming from output of vehicle assembly 220 upon an occurrence of an overvoltage event. Thus, peak-current suppressor 124 serves as another layer of protection against overvoltage event across output of vehicle assembly 220.

[0055] According to some embodiments of the present invention the correct operation mode of peak-current suppressor 124 may be tested by testing circuitry 128. Upon such a test, testing circuitry 128 instructs current source to inject a current into peak-current suppressor 124 in a level that is sufficient to check the ability of peak-current suppressor 124 to suppress a peak current.

[0056] Advantageously in this embodiment, testing circuitry 128 implements a built-in test of controlled switch circuitry 125 without applying overvoltage across the output of vehicle assembly. Apart from checking the operation of the gate of controlled switch circuitry, it further verifies that peak-current suppressor 124 is indeed suppressing undesirable peakcurrents that may be resultant of an overvoltage event. This check can be carried out periodically while EV is operating and also prior to charging and during charging is predefined intervals.

[0057] Figure 3 is a block diagram of a vehicle assembly 320 with an overvoltage protection circuitry according to some embodiments of the present invention designed to address an overvoltage event in accordance with the aforementioned conditions. Ground assembly 110 may include a ground assembly power circuitry 112 which is controlled by ground assembly controller 113 and may be configured to feed transmitter coils 111 with the electrical power required to create the magnetic needed for the wireless power transfer with vehicle assembly 120 as part of a wireless power transfer system 300.

[0058] According to some embodiments of the present invention, vehicle assembly 320 may be placed on board an electric vehicle (not shown) and may include receiver coils 121 which may be coupled to transmitter coils 111. Receiver coils 121 may feed the input of a rectifier 122 configured to rectify the alternating current into direct current. Rectifier 122 in turn feeds the input of a direct current (DC) filter 123 which reduces the harmonies of the power signal passing through it. The output of DC filter 123 is also effectively the output of vehicle assembly 320 which may feed the EV battery 130 or a capacitor which in turn feeds the motor (not shown) of the EV.

[0059] According to some embodiments of the present invention, detection circuitry 124 may receive as an input, the voltage across the output of vehicle assembly 320 and the output of detection circuitry 124 may be connected to a vehicle assembly controller 127.

[0060] The input of controlled switch circuitry 125 is connected to the output of vehicle assembly 120 and the output of controlled switch circuitry 125 is connected to an input of a bypass circuitry 126.

[0061] According to some embodiments of the present invention, one of the outputs of vehicle assembly controller 127 is connected to a control input of the controlled switch circuitry.

[0062] According to some embodiments of the present invention, vehicle assembly may further include a controllable current source 129 which may be controlled by a testing circuitry 128 which in turn may be controlled by vehicle assembly controller 127. The output of current source 129 may be connected to the gate of controlled switch circuitry 125.

[0063] In operation, ground assembly transmits energy via transmitter coils 111 to receiver coils 121 usually on demand possibly in accordance with a communication between vehicle assembly 121 and ground assembly 110 which is beyond the scope of embodiments of the present invention.

[0064] According to some embodiments of the present invention, detection circuitry 124 is configured to detect an overvoltage event across the output of vehicle assembly 320. An overvoltage event may occur whenever voltage level across an output of the vehicle assembly goes beyond a specific level, or when the voltage gradient across an output of the vehicle assembly goes beyond a specific voltage gradient.

[0065] According to some embodiments of the present invention, controlled switch circuitry 125 diverts current off the output of the vehicle assembly 320, into by-pass circuitry 126, upon detection of an overvoltage event by detection circuitry 124 across the output of the vehicle assembly.

[0066] According to some embodiments of the present invention, controlled switch circuitry may be operated directly by detection circuitry 124 or via vehicle assembly controller 127.

[0067] According to some embodiments of the present invention, bypass circuitry 126 may be implemented as a rectifier having two sets positive-side diodes and negative-side diodes and once an overvoltage event has been detected by detection circuitry 124 the switch in controlled switch circuitry 125 divert the current from output of vehicle assembly 320 into the rectifier having two sets positive-side diodes and negative-side diodes which is in turn grounded to earth.

[0068] According to some embodiments of the present invention, controlled switch circuitry 126 may include a silicon-controlled rectifier (SCR). The controlled switch can also be implemented as a power metal-oxide-semiconductor field-effect transistor (MOSFET) or insulated-gate bipolar transistor (IGBT) and bypass circuitry 126 may be implemented one or more sets of power diodes connected in series to the ground.

[0069] According to some embodiments of the present invention, in various points of time when it is desirable to verify the correct operation of controlled switch circuitry 125 specifically whenever an overvoltage event has not been detected by detection circuitry 124, current source 129 may generate a current at a level sufficient to activate the gate of controlled switch circuitry 125 and thus verify that controlled switch circuitry 125 is effectively a switch. This can be achieved by testing circuitry 128 controlling a current source 129 to inject such a current into the gate of controlled switch circuitry 125 and measure the current level flowing as in indication that the gate has been opened.

[0070] According to some embodiments of the present invention, vehicle assembly may further include a pulse resistor 314 connected between the output of DC filter 123 (being the output of vehicle assembly 320) and between the gate of controlled switch circuitry 125. Pulse resistor 314 may further be connected and fed by controlled current source 129.

[0071] According to some embodiments of the present invention, pulse resistor 314 may delay the flow of an electrical current coming from output of vehicle assembly 320 upon an occurrence of an overvoltage event. Thus, pulse resistor 314 serves as another layer of protection against overvoltage event across output of vehicle assembly 320.

[0072] According to some embodiments of the present invention, a fuse 316 may also be connected in series between pulse resistor 314 and controlled switch circuitry 125. The fuse is selected that it becomes an open circuit at a current beyond a certain values possibly 0.25 A.

[0073] According to some embodiments of the present invention the correct operation mode of both pulse resistor 314 and fuse 316 may be checked so as to ensure that in a case of an overvoltage event they will work properly. Fir the pulse resistor, upon such a test, testing circuitry 128 instructs current source to inject a current into pulse resistor 314 in a level that is sufficient to check the ability of pulse resistor 314 to suppress a peak current. For the fuse the test may consist on checking that it serves as a shortcut and has not been turned into an open circuit yet.

[0074] Advantageously in this embodiment, testing circuitry 128 implements a built-in test of controlled switch circuitry 125 without applying overvoltage across the output of vehicle assembly. Apart from checking the operation of the gate of controlled switch circuitry, it further verifies that pulse resistor 314 is indeed suppressing undesirable peak-currents that may be resultant of an overvoltage event and that the fuse 316 has not been burnt. This check can be carried out periodically while EV is operating and also prior to charging and during charging is predefined intervals.

[0075] Figure 4 is a block diagram of a vehicle assembly 420 with an overvoltage protection circuitry according to some embodiments of the present invention designed to address an overvoltage event in accordance with the aforementioned conditions. Ground assembly 110 may include a ground assembly power circuitry 112 which is controlled by ground assembly controller 113 and may be configured to feed transmitter coils 111 with the electrical power required to create the magnetic needed for the wireless power transfer with vehicle assembly 220 as part of a wireless power transfer system 400.

[0076] According to some embodiments of the present invention, vehicle assembly 420 may be placed on board an electric vehicle (not shown) and may include receiver coils 121 which may be coupled to transmitter coils 111. Receiver coils 121 may feed the input of a rectifier 122 configured to rectify the alternating current into direct current. Rectifier 122 in turn feeds the input of a direct current (DC) filter 123 which reduces the harmonies of the power signal passing through it. The output of DC filter 123 is also effectively the output of vehicle assembly 420 which may feed the EV battery 130 or a capacitor which in turn feeds the motor (not shown) of the EV.

[0077] According to some embodiments of the present invention, detection circuitry 124 may receive as an input, the voltage across the output of vehicle assembly 220 and the output of detection circuitry 124 may be connected to a vehicle assembly controller 127.

[0078] The input of controlled switch circuitry 125 is connected to the output of vehicle assembly 220 and the output of controlled switch circuitry 125 is connected to an input of a bypass circuitry 126.

[0079] According to some embodiments of the present invention, one of the outputs of vehicle assembly controller 127 is connected to a control input of the controlled switch circuitry.

[0080] According to some embodiments of the present invention, vehicle assembly may further include a controllable current source 129 which may be controlled by a testing circuitry 128 which in turn may be controlled by vehicle assembly controller 127. The output of current source 129 may be connected to the gate of controlled switch circuitry 125.

[0081] In operation, ground assembly transmits energy via transmitter coils 111 to receiver coils 121 usually on demand possibly in accordance with a communication between vehicle assembly 220 and ground assembly 110 which is beyond the scope of embodiments of the present invention.

[0082] According to some embodiments of the present invention, detection circuitry 124 is configured to detect an overvoltage event across the output of vehicle assembly 220. An overvoltage event may occur whenever voltage level across an output of the vehicle assembly goes beyond a specific level, or when the voltage gradient across an output of the vehicle assembly goes beyond a specific voltage gradient.

[0083] According to some embodiments of the present invention, controlled switch circuitry 125 diverts current off the output of the vehicle assembly 220, into by-pass circuitry 126, upon detection of an overvoltage event by detection circuitry 124 across the output of the vehicle assembly.

[0084] According to some embodiments of the present invention, controlled switch circuitry may be operated directly by detection circuitry 124 or via vehicle assembly controller 127.

[0085] According to some embodiments of the present invention, bypass circuitry 126 may be implemented as a rectifier having two sets positive-side diodes and negative-side diodes and once an overvoltage event has been detected by detection circuitry 124 the switch in controlled switch circuitry 125 divert the current from output of vehicle assembly 120 into the rectifier having two sets positive-side diodes and negative-side diodes which is in turn grounded to earth.

[0086] According to some embodiments of the present invention, controlled switch circuitry 126 may include a silicon-controlled rectifier (SCR). The controlled switch can also be implemented as a power metal-oxide-semiconductor field-effect transistor (MOSFET) or insulated-gate bipolar transistor (IGBT) and bypass circuitry 126 may be implemented one or more sets of power diodes connected in series to the ground.

[0087] According to some embodiments of the present invention, in various points of time when it is desirable to verify the correct operation of controlled switch circuitry 125 specifically whenever an overvoltage event has not been detected by detection circuitry 124, current source 129 may generate a current at a level sufficient to activate the gate of controlled switch circuitry 125 and thus verify that controlled switch circuitry 125 is effectively a switch. This can be achieved by testing circuitry 128 controlling a current source 129 to inject such a current into the gate of controlled switch circuitry 125 and measure the current level flowing as in indication that the gate has been opened.

[0088] According to some embodiments of the present invention, vehicle assembly may further include a peak-current suppressor 124 connected between the output of DC filter 123 (being the output of vehicle assembly 220) and between the gate of controlled switch circuitry 125. peak-current suppressor 124 may further be connected and fed by controlled current source 129.

[0089] According to some embodiments of the present invention, peak-current suppressor 124 may include one or more electrical elements that prevent or delay the flow of an electrical current coming from output of vehicle assembly 220 upon an occurrence of an overvoltage event. Thus, peak-current suppressor 124 serves as another layer of protection against overvoltage event across output of vehicle assembly 420.

[0090] According to some embodiments of the present invention the correct operation mode of peak-current suppressor 124 may be tested by testing circuitry 128. Upon such a test, testing circuitry 128 instructs current source to inject a current into peak-current suppressor 124 in a level that is sufficient to check the ability of peak-current suppressor 124 to suppress a peak current.

[0091] Advantageously in this embodiment, testing circuitry 128 implements a built-in test of controlled switch circuitry 125 without applying overvoltage across the output of vehicle assembly. Apart from checking the operation of the gate of controlled switch circuitry, it further verifies that peak-current suppressor 124 is indeed suppressing undesirable peakcurrents that may be resultant of an overvoltage event. This check can be carried out periodically while EV is operating and also prior to charging and during charging is predefined intervals.

[0092] In accordance with some embodiments of the present invention bypass circuitry 126 typically include, similarly to rectifier 122 one branch of positive-side diodes as well as matching branch of negative-side diodes which typically include 4 power diodes in each branch but other numbers of diodes may be used. In order to reduce the number of diodes used in the circuitry it is suggested by the inventor of the present invention to use the negative side diodes 224 as the negative side diodes of bypass circuitry 126 together with positive-side diodes 228 of bypass circuitry 126 so bypass circuitry 126 shares negative side diodes 224 with rectifier 122. This suggestion saves the use of a branch of negative side diodes. In order to implement this solution, the branch of negative side diodes 224 connected in parallel to positive side diodes 226 of rectifier 122 is further connected is parallel to the branch of positive side diodes 228 of bypass circuitry 126.

[0093] The aforementioned flowchart and diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each portion in the flowchart or portion diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the portion may occur out of the order noted in the figures. For example, two portions shown in succession may, in fact, be executed substantially concurrently, or the portions may sometimes be executed in the reverse order, depending upon the functionality involved, It will also be noted that each portion of the portion diagrams and / or flowchart illustration, and combinations of portions in the portion diagrams and / or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

[0094] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system or an apparatus. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit”, “module” or “system”.

[0095] The aforementioned figures illustrate the architecture, functionality, and operation of possible implementations of systems and apparatus according to various embodiments of the present invention. Where referred to in the above description, an embodiment is an example or implementation of the invention. The various appearances of “one embodiment,” “an embodiment” or “some embodiments” do not necessarily all refer to the same embodiments.

[0096] Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment.

[0097] Reference in the specification to “some embodiments”, “an embodiment”, “one embodiment” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the inventions. It will further be recognized that the aspects of the invention described herein above may be combined or otherwise coexist in embodiments of the invention.

[0098] It is to be understood that the phraseology and terminology employed herein is not to be construed as limiting and are for descriptive purpose only.

[0099] The principles and uses of the teachings of the present invention may be better understood with reference to the accompanying description, figures and examples.

[00100] It is to be understood that the details set forth herein do not construe a limitation to an application of the invention.

[00101] Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones outlined in the description above.

[00102] It is to be understood that the terms “including”, “comprising”, “consisting of’ and grammatical variants thereof do not preclude the addition of one or more components, features, steps, or integers or groups thereof and that the terms are to be construed as specifying components, features, steps or integers.

[00103] If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element.

[00104] It is to be understood that where the claims or specification refer to “a” or “an” element, such reference is not construed that there is only one of that element.

[00105] It is to be understood that where the specification states that a component, feature, structure, or characteristic “may”, “might”, “can” or “could” be included, that particular component, feature, structure, or characteristic is not required to be included.

[00106] Where applicable, although state diagrams, flow diagrams or both may be used to describe embodiments, the invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described.

[00107] Methods of the present invention may be implemented by performing or completing manually, automatically, or a combination thereof, selected steps or tasks.

[00108] The term “method” may refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the art to which the invention belongs.

[00109] The descriptions, examples and materials presented in the claims and the specification are not to be construed as limiting but rather as illustrative only.

[00110] Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belongs, unless otherwise defined.

[00111] The present invention may be implemented in the testing or practice with materials equivalent or similar to those described herein.

[00112] While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other or equivalent variations, modifications, and applications are also within the scope of the invention. Accordingly, the scope of the invention should not be limited by what has thus far been described, but by the appended claims and their legal equivalents.

Claims

1. A circuitry for testing a protection mechanism against an overvoltage event at a vehicle assembly of a vehicle having at least one motor for electric propulsion, said vehicle assembly associated with a ground assembly as a part of a wireless power transfer system for electric vehicles, wherein said protection mechanism comprises a controlled switch to divert current off the output of the vehicle assembly, into a by-pass circuitry, upon detection of the overvoltage event across the output of the vehicle assembly, said circuitry for testing comprising:a voltage or current source configured to apply an electrical charge into a gate of the controlled switch at a level which is sufficient to turn the controlled switch on, so as to verify that the controlled switch and the by-pass circuitry serve as a shortcut of the output of the vehicle assembly.

2. The circuitry of claim 1, wherein said electrical charge applied into a gate of the controlled switch is sufficiently below so that an overvoltage event at the output of the vehicle assembly does not occur.

3. The circuitry according to claim 1, wherein the overvoltage event comprises a voltage level across the output of the vehicle assembly going beyond the predefined level, or a voltage gradient across the output of the vehicle assembly going above the predefined voltage gradient.

4. The circuitry of claim 1, wherein the controlled switch comprises a silicon-controlled rectifier (SCR).

5. The circuitry of claim 1, wherein the vehicle assembly comprises a rectifier having a branch of positive-side diodes and branch of negative-side diodes and wherein the by-pass circuity comprises a branch of positive-side diodes and wherein the branch of negative-side diodes of the rectifier is further used by the by-pass circuitry as a branch of negative-side diodes of the by-pass circuitry.

6. The circuitry of claim 1, further comprising peak-current suppressor connected in parallel to the output of the vehicle assembly only when the controlled switch is on, andwherein the circuitry for testing the protection mechanism is configured to apply a current through the peak-current suppressor and verify continuity of said current.

7. The circuitry of claim 6, wherein the peak-current suppressor comprises a pulse resistor connected in parallel to the output of the vehicle assembly wherein the circuitry for testing the protection mechanism is configured to apply a current for verifying that the pulse resistor acts as a pulse resistor.

8. The circuitry of claim 7, wherein the peak-current suppressor comprises a fuse connected in series to the pulse resistor, and wherein the circuitry for testing the protection mechanism is configured to apply a current for verifying that the fuse acts as a shortcut.

9. The circuitry of claim 1, wherein the circuitry for testing is configured to verify operation of the controlled switch without applying actual overvoltage thereto.

10. A vehicle assembly associated with a ground assembly as a part of a wireless power transfer system for electric vehicles, said vehicle assembly comprising:a circuitry for testing a protection mechanism against an overvoltage event comprising a controlled switch to divert current off the output of the vehicle assembly, into a by-pass circuitry, upon detection of the overvoltage event across the output of the vehicle assembly, said circuitry for testing comprising:a voltage or current source configured to apply an electrical charge into a gate of the controlled switch at a level which is sufficient to turn the controlled switch on, so as to verify that the controlled switch and the by-pass circuitry serve as a shortcut of the output of the vehicle assembly.

11. The vehicle assembly of claim 10, wherein said electrical charge applied into a gate ofthe controlled switch is sufficiently below so that an overvoltage event at the output of the vehicle assembly does not occur.

12. The vehicle assembly of claim 10, wherein the overvoltage event comprises a voltage level across the output of the vehicle assembly going beyond the predefined level, or a voltage gradient across the output of the vehicle assembly going above the predefined voltage gradient.

13. The vehicle assembly of claim 10, wherein the controlled switch comprises a silicon-controlled rectifier (SCR).

14. The vehicle assembly of claim 10, wherein the vehicle assembly comprises a rectifier having a branch of positive-side diodes and branch of negative-side diodes and wherein the by-pass circuity comprises a branch of positive-side diodes and wherein the branch of negative-side diodes of the rectifier is further used by the by-pass circuitry as a branch of negative-side diodes of the by-pass circuitry.

15. The vehicle assembly of claim 10, further comprising peak-current suppressor connected in parallel to the output of the vehicle assembly only when the controlled switch is on, and wherein the circuitry for testing the protection mechanism is configured to apply a current through the peak-current suppressor and verify continuity of said current.

16. The vehicle assembly of claim 15, wherein the peak-current suppressor comprises a pulse resistor connected in parallel to the output of the vehicle assembly wherein the circuitry for testing the protection mechanism is configured to apply a current for verifying that the pulse resistor acts as a pulse resistor.

17. The vehicle assembly of claim 16, wherein the peak-current suppressor comprises a fuse connected in series to the pulse resistor, and wherein the circuitry for testing the protection mechanism is configured to apply a current for verifying that the fuse acts as a shortcut.

18. The vehicle assembly of claim 10, wherein the circuitry for testing is configured to verify operation of the controlled switch without applying actual overvoltage thereto.21

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