Electronic lock of a motor vehicle locking device equipped with an improved auxiliary energy source

Abstract

Electronic lock arrangement (1) for a locking device (2) of a motor vehicle (3), comprising an actuator group (6') operable to control an actuation of the locking device (2), and an electric motor (9) controllable to drive the actuator group (6') and designed to be driven by a main supply voltage (V batt ) providing main power source (4) of the motor vehicle (3), wherein the electronic lock arrangement (1) comprises an auxiliary power source (20) and a control unit (21) configured to control the auxiliary power source (20) to supply the electric motor (9) during a fault operating condition deviating from the normal operating condition, wherein the auxiliary energy source (20) comprises a supercapacitor array (22) configured to store energy during the normal operating condition and to provide an auxiliary supply voltage (V sc ) to supply the electric motor (9), wherein the supercapacitor group (22) comprises a first (23a) and a second (23b) supercapacitor cell connected to each other to jointly generate the auxiliary supply voltage (V sc ), wherein the auxiliary energy source (20) and the control unit (21) are arranged within a housing (11) of the electronic lock arrangement (1), wherein the auxiliary power source (20) further comprises a voltage boost module (26) coupled to the supercapacitor array (22) and configured to boost a level of the auxiliary supply voltage (V sc ) to provide a boost voltage (V boost) designed to supply the electric motor (9), and wherein the auxiliary power source (20) further comprises a balancing module (25) connected to the supercapacitor group (22) and operable to determine a desired voltage level across the first (23a) and second (23b) supercapacitor cells.

Description

Technical area

[0001] The present invention relates to an electronic lock (commonly known as e-lock) of a motor vehicle locking device equipped with an improved auxiliary power source. background

[0002] In the following description and the accompanying claims, the term "closing device" is used to generally designate any element which is movable between an open position and a closed position and which opens or closes access to an interior of a motor vehicle, and thus includes a luggage compartment, a rear lid, a bonnet lid or other enclosed spaces, window lifters, sunroofs, in addition to the side doors of a motor vehicle, to which the following description will make explicit reference purely by way of example.

[0003] It is known that electric locks are provided in motor vehicles, for example to control the opening and closing of side doors.

[0004] An electric door lock typically includes a rotary latch that is selectively rotatable relative to a locking bolt attached to a door jamb to latch or lock and unlatch or unlock the door. The electric door lock includes a pawl that selectively engages the rotary latch to prevent the pawl from rotating. The electric lock includes an electric motor electrically connected to a vehicle's main power source (e.g., the vehicle's 12V battery) to directly or indirectly drive the pawl via an electrically powered actuator.

[0005] As is known, a common problem of electric locks concerns the control of the opening and closing of the doors even in the event of a failure of the vehicle's main power supply or in the event of interruptions or a breakdown of the electrical connection between the main power supply and the electric motor in the lock, as required by safety regulations; this type of situation can occur, for example, in the event of a collision or accident involving the vehicle.

[0006] One possible solution to this problem involves the use of a mechanical release mechanism in the lock, which serves as a mechanical safeguard for the electrically operated side door lock.

[0007] However, the presence of a redundant mechanical mechanism entails greater space requirements, weight, and additional costs, and represents a further limitation in the door design.

[0008] Therefore, the use of an auxiliary power source for the electric lock was proposed to supply electrical energy to the lock's electric motor in the event of a failure or interruption of the vehicle's main power supply.

[0009] This auxiliary power source is typically kept charged by the main power supply during normal operation so that it is readily available when the need arises, for example in the event of a collision or accident.

[0010] However, the design of an auxiliary power source and the relevant electronic circuits for the electric lock assembly has proven to be a difficult task, for example due to size requirements, just as meeting the desired electrical performance has proven difficult, for example in terms of energy density or current output, particularly under vehicle operating conditions.

[0011] In this regard, EP 0 694 664 A1 discloses an auxiliary power source for a door lock, which is designed to supply power to the lock during emergency situations and which provides an auxiliary battery arranged inside the door in which the lock is arranged.

[0012] Another known solution, discussed in DE 201 21 915 U1, discloses the use of a capacitor bank as an auxiliary power source for a vehicle door lock. The capacitor bank is coupled to a circuit board and externally connected to the locking device. The capacitor bank comprises a multitude of high-voltage capacitors (capable of withstanding up to 14 V) connected in series or parallel, thus taking up considerable space on the circuit board. Furthermore, such a solution generally requires an additional auxiliary power source, since the supercapacitor bank is only capable of supplying power for a limited time. In other words, the capacitor bank may not be able to guarantee a sufficient and independent auxiliary power source for the vehicle lock.

[0013] DE 601 06 993 T2 discloses a locking unit for a motor vehicle door and a method for testing the functionality of a lock module with this unit.

[0014] US 2009 / 0 102 434 A1 discloses an auxiliary power supply device for a vehicle, comprising a capacitor unit, a temperature detector, and a charge controller. The capacitor unit has at least one electric double-layer capacitor. The temperature detector detects the temperature near the capacitor unit. The charge controller controls the charging voltage of the capacitor unit based on a detection result of the temperature detector.

[0015] JP 2009 - 144 441 A discloses a door locking system for a vehicle.

[0016] Therefore, there is a need in the field for an optimized and reliable auxiliary power source for an electric lock in a motor vehicle. Disclosure of the invention

[0017] It is therefore an object of certain aspects of the present invention to provide an electronic lock with an auxiliary power source designed to meet the above-mentioned need.

[0018] This object can be achieved by an electronic locking device according to claim 1 and a motor vehicle according to claim 17. Short description of the drawings

[0019] A preferred, non-limiting embodiment of certain aspects of the present invention will be described by way of example with reference to the accompanying drawings, in which - Fig. 1 is a schematic representation of a motor vehicle with a locking device and a respective e-lock arrangement, - Fig. 2 a general block diagram of an electronic control circuit of the e-lock arrangement of the Fig. 1 is, - Fig. 3 a circuit diagram of the electronic control circuit of the Fig. 2 is, - Fig. 4 and Fig. 5 Show flowcharts of processes performed by a diagnostic module of the auxiliary power source of the Fig. 1 be executed, - Fig. 6 is a diagram of an electrical signal in the electronic control circuit of the Fig. 2 is, - Fig. 7a to 7c Diagrams of capacitance values ​​in the electronic control circuit of the Fig. 2 under different operating conditions, and - Fig. 8 shows a flow chart of further processes carried out by the diagnostic module of the auxiliary power source of the Fig. 1 can be executed. Preferred embodiment of the invention

[0020] The reference number 1 in the Fig. 1 denotes as a whole an electronic locking arrangement (hereinafter e-lock arrangement 1) connected to a side door 2 of a motor vehicle 3 (it should be emphasized again, however, that the e-lock arrangement 1 can be connected in the same way to any type of locking device of the motor vehicle 3).

[0021] The e-lock arrangement 1 is connected to a main power source 4 of the motor vehicle 3, for example a battery voltage V batt from the main battery providing 12 V, via an electrical connecting element 5, for example a power cable (the main power source 4 may equally comprise another source of electrical energy within the motor vehicle 3, for example an alternator).

[0022] The e-lock assembly comprises an actuation group 6 with an electric motor operable to control actuation of the door 2 (or generally the vehicle locking device).

[0023] According to one possible embodiment, the actuating group 6' comprises a rotary latch 6 that is selectively rotatable to engage a locking bolt 7 (which is attached to the vehicle body of the motor vehicle in a manner not shown in detail, for example, to the so-called "A-pillar" or the "B-pillar"). When the rotary latch 6 is rotated into a latching position relative to the locking bolt 7, the side door 2 is in a closed operating state. A pawl 8, driven by an electric motor 9 for movement between an engaged position and a disengaged position, selectively engages the rotary latch 6 to prevent it from rotating.

[0024] The e-lock assembly 1 further comprises an electronic control circuit 10 comprising, for example, a microcontroller or other known processing unit, which may conveniently be embedded and arranged in a same housing or container 11 (shown schematically) with the actuation group 6' of the e-lock assembly 1, thereby providing an integrated, compact and easy-to-assemble unit.

[0025] The electronic control circuit 10 is coupled to the electric motor 9 and provides it with drive signals S d ready, as will be shown in more detail below.

[0026] The electronic control circuit 10 is electrically connected via a data bus 14 to a vehicle main management unit 12 (also known as main ECU or “on-board computer”), which is configured to control general operation of the motor vehicle 3, to exchange signals, data, commands and / or information.

[0027] As in Fig. 2, the electronic control circuit 10 is further connected (directly and / or indirectly via the vehicle main management unit 12) to a plurality of different sensors 15 (shown schematically) of the motor vehicle 3, such as handle sensing sensors 15a (which sense the actuation of external and / or internal handles 16), crash or impact sensors 15b, lock switch sensors 15, and the like; conveniently, the electronic control circuit 10 also receives feedback information about the lock actuation from position sensors 15d, such as Hall sensors configured to detect the operating position of, for example, the rotary latch 6 and / or the pawl 8.

[0028] The electronic control circuit 10 is also connected to the main power source 4 of the motor vehicle 3 to control the battery voltage V battto receive; the electronic control circuit 10 is therefore able to check whether the value of the battery voltage V batt falls below a predetermined threshold to immediately determine whether an emergency condition (in which an auxiliary power source may be required) occurs.

[0029] As shown in the schematic block diagram of the Fig. 2, the electronic control circuit 10 comprises an embedded and integrated auxiliary power source 20 configured to supply electrical energy to the actuation group 6' and the lock electric motor 9 and the same electronic control circuit 10 in the event of a failure or interruption of the main power supply from the main power source 4 of the motor vehicle 3.

[0030] More specifically, the electronic control circuit 10 comprises a control unit 21, which is equipped, for example, with a microcontroller, a microprocessor or an analog calculation module 21a and which is connected to the auxiliary power source 20 and the actuation group 6' of the e-lock assembly 1 in order to control their operation.

[0031] The control unit 21 has a built-in memory 21b, for example, a non-volatile random access memory (RAID), which is connected to the calculation module 21a and stores suitable programs and calculation instructions (for example, in the form of firmware). It should be appreciated that the control unit 21 may alternatively comprise a logic circuit of discrete components to perform the functions of the calculation module 21a and the memory 21b.

[0032] According to one aspect of the present solution, the auxiliary power source 20 comprises a group of low-voltage supercapacitors 22 (hereinafter, supercapacitor group 22) as a power supply unit (or energy reservoir) to supply the e-lock assembly 1 with an auxiliary power even in the event of a power failure. Supercapacitors may comprise electrolytic double-layer capacitors, pseudocapacitors, or a combination thereof.

[0033] Supercapacitors advantageously provide high energy density and high output current capability and exhibit no memory effects. Furthermore, supercapacitors are small and easy to integrate, have an extended temperature range, a long lifetime, and can withstand a very high number of charging cycles. Supercapacitors are non-toxic and do not pose any explosion or fire risks, making them suitable for hazardous conditions, such as automotive applications.

[0034] As in Fig. 3, the supercapacitor group 22 may, according to a possible embodiment, comprise two supercapacitor cells 23a, 23b connected in series between a first node 22a and a second node 22b (for example, connected to a reference ground voltage) and defining an intermediate node 22c, wherein each cell, when charged, provides a voltage level of, for example, 2.5 V to 2.7 V to collectively provide a supercapacitor voltage V sc in a range of, for example, 3 V to 5 V, which can be used as an auxiliary power supply in emergency situations when the energy from the main power source 4 of the motor vehicle 3 is not available. The supercapacitor cells 23a, 23b are therefore of the low-voltage type and also have a high capacitance, for example, in the range of 16 F to 20 F, for example 18 F.

[0035] As will be discussed in more detail below, the auxiliary energy source 20 further comprises a charging module 24, a balancing module 25 and an amplification module 26.

[0036] The charging module 24 is electrically connected to the supercapacitor group 22 and is configured to charge the battery from the battery voltage V batt when power is available from the main power source 4, to recharge the supercapacitor group 22 so that the supercapacitor group 22 can offer full energy storage for emergency situations and any loss currents are compensated.

[0037] The balancing module 25 is electrically connected to the supercapacitor array 22 and is configured to ensure that both supercapacitor cells 23a, 23b have a desired cell voltage value, in particular, an equal cell voltage value during operation (to achieve a balanced operating condition). The balancing module 25 also prevents the supercapacitor cells 23a, 23b from having a cell voltage above a maximum desired cell voltage level, which protects the supercapacitors against overcharging.

[0038] The amplification module 26 receives at its input the supercapacitor voltage V generated by the supercapacitor group 22 scand is configured to amplify, i.e., increase, its value to standard vehicle voltages (e.g., 9 V to 16 V) and provide enough output current capability to drive standard vehicle electric motors, such as the electric motor 9 of the e-lock assembly 1. In fact, the supercapacitor voltage V sc be too low to provide an efficient auxiliary power source for directly driving the electric motor 9 in emergency situations, such as lost or insufficient power supply from the main power source 4 of the motor vehicle 3.

[0039] The amplification module 26 therefore provides an amplified voltage V at its output (which is also the output of the auxiliary power source 20). boost as a function of the supercapacitor voltage V sc The amplified voltage V boostis then received by an output module of the electronic control circuit 10, which includes, for example, an integrated H-bridge module 27, the output of which drives the electric motor 9 of the e-lock assembly 1.

[0040] The auxiliary power source 20 further comprises a diagnostic module 28 operatively connected to the supercapacitor array 22 and configured to monitor the state of life of the supercapacitors during the charging process and based on the same charging process by measuring their voltage values, capacitance values, and internal equivalent resistances (DCR - direct current resistance), as will again be described below.

[0041] A temperature sensor 29 is configured to monitor the operating temperature of the supercapacitor array 22 and is coupled to the diagnostic module 28 to provide the measured temperature information; for example, the temperature sensor 29 may comprise a NTC (negative temperature coefficient) resistor disposed near the supercapacitor array 22.

[0042] The diagnostic module 28 is operatively connected to the control unit 21 to provide the diagnostic information, for example including the value of the supercapacitor voltage V sc . In a possible embodiment not shown, the diagnostic module 28 may be implemented as a diagnostic routine in the control unit 21, which is executed by the microprocessor or microcontroller of the control unit 21.

[0043] More precisely, and as shown in the schematic diagram of the Fig. 3, the charging module 24 of the auxiliary energy source 20 has a first input 24a which is designed to receive a drive voltage V dr whose value corresponds to the higher value of the amplified voltage V boost and the battery voltage V batt corresponds; in particular, the drive voltage V dr equal to the battery voltage V batt during normal operation of the e-lock assembly 1 for charging the supercapacitor group 22 and is equal to the value of the boosted voltage V boost from the amplification module 26 during emergency or fault situations.

[0044] The charging module 24 also has a second input 24b designed to receive a charging activation signal En_ch from the control unit 21 of the electronic control circuit 10, which is a digital signal whose value indicates the request determined by the same control unit 21 to activate or stop the charging of the supercapacitor group 22.

[0045] The charging module 24 has a power switch 24c and a power resistor 24d.

[0046] The power switch 24c, for example a solid-state switch such as a MOSFET switch, is connected between the first input 24a and the power resistor 24d and has a control terminal coupled to the second input 24b, whereby it receives the charging activation signal En_ch.

[0047] The power resistor 24d is connected between the power switch 24c and the first node 22a of the supercapacitor group 22.

[0048] When activated by the charging activation signal En_ch via the power switch 24c, the supercapacitor group 22 is charged with the battery voltage V batt through the power resistor 24d.

[0049] In particular, the control unit 21 of the electronic control circuit 10 can generate a PWM (pulse width modulated) charging activation signal En_ch during charging of the supercapacitor group 22, whereby the supercapacitor group 22 is charged in rapid succession with the battery voltage V batt connected or disconnected.

[0050] As already indicated, the charging of the supercapacitor group 22 can be a continuous process as long as the control unit 21 of the electronic control circuit 10 maintains a value of the battery voltage V batt which is greater than a preset threshold indicating a possible failure affecting the main power source 4.

[0051] In a possible passive embodiment, the balancing module 25 has a first and a second balancing resistor 25a, 25b with an equal resistance value. The first balancing resistor 25a is connected between the intermediate node 22c and the first node 22a of the supercapacitor group 22 via the interposition of a first balancing switch 25c, whereby it can be optionally connected in parallel with the first supercapacitor cell 23a. The second balancing resistor 25b is connected between the intermediate node 22c and the second node 22b of the supercapacitor group 22 via the interposition of a second balancing switch 25d, whereby it can be optionally connected in parallel with the second supercapacitor cell 23b.

[0052] The first and second equalization switches 25c, 25d are solid-state switches comprising, for example, a respective MOSFET transistor, both of which are controlled by an equalization activation signal EN_eq received from the control unit 21 of the electronic control circuit 10 at a control input 25e of the equalization module 25.

[0053] In particular, the equalization activation signal EN_eq controls the first and second equalization switches 25c, 25d to activate or stop the equalization operation to save energy stored in the supercapacitor group 22 when the same supercapacitor group 22 is not used as an auxiliary power source.

[0054] The amplification module 26 is implemented according to a possible embodiment by a PWM boost converter (or DC / DC boost converter) and comprises an activation switch 26a, for example a MOSFET solid-state switch, which is connected between the first node 22a of the supercapacitor group 22, and thus the supercapacitor voltage V sc receiving, and a first intermediate node 26b.

[0055] A storage capacitor 26b' is connected to the first intermediate node 26b and is charged to the supercapacitor voltage V sc charged when the activation switch 26a is closed, which defines a self-turn-on signal S_ON having a high voltage value at the same intermediate node 26b.

[0056] The activation switch 26a has a control terminal that receives a boost deactivation signal boost_OFF from the control unit 21 of the electronic control circuit 10; during normal operation, when the main power source 4 is available, the boost deactivation signal boost_OFF deactivates the PWM boost converter and maintains the OFF state, since the detected battery voltage V batt is not critical.

[0057] The control terminal of the activation switch 26a also receives a boost activation signal boost_ON, whose value is determined by external user actions (i.e., it is not generated by the control unit 21 in the electronic control circuit 10), and the turn-on signal S_ON.

[0058] After the amplification module 26 has been activated, it is automatically maintained in an ON state, in particular by the high value of the switch-on signal S_ON, until it is switched off by the control unit 21 of the electronic control circuit 10 when the auxiliary power is no longer required or energy is to be stored in the supercapacitor group 22.

[0059] According to a possible embodiment, the boost activation signal boost_ON switches to the ON state, thereby activating the PWM boost converter, as soon as the handle detection sensors 15a detect a user actuation of the inner or outer handles 16 of a side door 2 of the motor vehicle 3. During an emergency situation, if there is a fault in the main power source 4, the auxiliary power source 20 is therefore immediately available to supply the e-lock assembly 1.

[0060] In particular, the amplification module 26 comprises: a gain induction element 26c connected between the first intermediate node 26b and a second intermediate node, a gain switch 26e connected between the second intermediate node 26d and the ground reference potential and having a control terminal, for example a solid-state switch such as a MOSFET switch, and a gain diode element 26f connected between the second intermediate node 26d and an output node 26g (which also represents an output terminal OUT for the entire auxiliary power source 20), at which the amplified voltage V boost is provided optionally.

[0061] According to one aspect of the present solution, the amplification module 26 further comprises an internal controller 26h, in particular a PWM controller, configured to provide a PWM control signal to the control terminal of the amplification switch 26e to control its amplification operation (in a manner known per se, which will not be discussed in detail here).

[0062] The internal controller 26h is connected to the first intermediate node to control the supercapacitor voltage V sc to receive, and is capable of independently managing the amplification on and off, thus enabling the auxiliary power source 20 to be enabled or activated even without any further action by the control unit 21 of the electronic control circuit 10.

[0063] A feedback switch 26i is connected between the output node 26g and the internal controller 26h to provide feedback of the value of the amplified voltage V boost to provide.

[0064] The control terminal of the feedback switch 26i is also connected to the first intermediate node 26b to receive the turn-on signal S_ON when the activation switch 26a is closed.

[0065] When switching to the closed state by the supercapacitor voltage V sc a feedback path is defined to enable voltage regulation in a closed loop by the internal control 26h (a voltage divider, not shown and implemented via an isolating resistor, may be present to separate the voltage feedback from the amplified voltage V boost provide).

[0066] The feedback switch 26i returns to the open state as soon as the gain module is turned off to reduce the current consumption over the feedback path, which is actually interrupted.

[0067] The amplification module 26 further comprises a selection diode 26j, the cathode terminal of which is connected to the output node 26g and the anode terminal of which is connected to the battery voltage V batt receives.

[0068] Accordingly, the highest value of the battery voltage V batt and the amplified voltage V boost than the drive voltage V dr which then drives the electric motor 9 of the e-lock assembly 1 (and also charges the supercapacitor group 22).

[0069] The operation of the diagnostic module 28 of the auxiliary power source 20 will now be discussed in more detail.

[0070] According to a possible embodiment, the diagnostic module 28 can be implemented in the control unit 21 of the electronic control circuit 10 as a diagnostic routine executed by the microprocessor or microcontroller of the calculation module 21a; for this reason, the control unit 21 can determine the value of the supercapacitor voltage V sc and / or monitor the voltage value at the intermediate node 22c between the supercapacitor cells 23a, 23b.

[0071] According to a possible embodiment, the temperature sensor 29 can also be integrated in the control unit 21.

[0072] Possible failure modes monitored by the diagnostic module 10 that may affect one or both of the supercapacitor cells 23a, 23b are as follows: - Circuit breakage fault, - short circuit fault, - Increase in leakage current, - Increase in equivalent series resistance, - Decrease in capacity value.

[0073] These failure modes or conditions can be detected in real time during operation of the e-lock assembly 1 using special logic and algorithms provided by the diagnostic routine.

[0074] In particular, an "open circuit fault" for one of the two supercapacitor cells 23a, 23b generates a corresponding fault in the entire series, which can be detected whenever there is essentially zero voltage across the supercapacitor series, even when they are charged.

[0075] A “short-circuit fault” of a supercapacitor cell 23a, 23b of the series produces a doubling of the series capacitance and a corresponding reduction in the value of the supercapacitor voltage V sc ; the voltage value at full charge cannot be reached and / or cannot be maintained over time.

[0076] An increase in the “leakage current” can be observed when the charged state of the supercapacitor cells 23a, 23b (the value of which can be set as a preset threshold) is not achieved even after a long charging time or when the value of the supercapacitor voltage V sc across the array is subjected to an unexpected change (for example, a change that is incompatible with the charging process applied to the supercapacitor array 22).

[0077] The increase in the “equivalent series resistance” of one of the supercapacitor cells 23a, 23b detects an increase in the resistance of the entire series, while the decrease in the “capacitance” of one of the supercapacitor cells 23a, 23b detects an increase in the capacitance of the entire series.

[0078] The open circuit and short circuit faults indicate a complete failure of the auxiliary power source 20, since the energy storage function of the supercapacitor cells 23a, 23b is eliminated; in other words, the e-lock assembly 1 can only operate properly when supplied by the main power source 4 of the motor vehicle 3.

[0079] In contrast, the other errors listed above are progressive, in particular when the measured values ​​(for example, capacitance and / or resistance values) reach a first alarm threshold, which may be suitably preset, the diagnostic module 28 is able to generate a pre-alarm indicating the onset error to the user or driver or to the workshop personnel, even if the supercapacitor cells 23a, 23b are still in a working state.

[0080] If the error then reaches a limit value (and the measured values ​​reach a second preset alarm threshold), the diagnostic module 28 can signal the complete failure of the auxiliary power source 20 and that the e-lock assembly 1 can only be operated when connected to the main power source 4 of the motor vehicle 3.

[0081] According to one aspect of the present solution, the capacity of the supercapacitor cells 23a, 23b is determined during their life cycle by the diagnostic module 28, which measures the time it takes to charge the supercapacitors from a partially charged voltage to a fully charged voltage when charging is performed via a series resistor (the power resistor 24d of the charging module 24) directly from the power supply voltage (the battery voltage V batt the main power source 4).

[0082] In particular, the diagnostic module 28, as shown in Fig. 4 at step 40, the time T1 to reach a partially charged voltage V1 having a value other than zero, starting from a fully discharged state, wherein the time T1 to reach a partially charged voltage V1 is based on the following expressions: V1=Vbatt(1−e−T1R−C) T1=−R⋅C⋅ln(1−V1Vbatt)

[0083] The diagnostic module 28 then determines at step 41 the time T2 to reach a fully charged voltage V2 based on the following expressions: V2=Vbatt(1−e−T2R⋅C) T2=−R⋅C⋅ln(1−V2Vbatt)

[0084] In the above expressions, C is the supercapacitor capacitance (either of the entire series, if the supercapacitor voltage V sc is considered, or a first of the supercapacitor cells 23a, 23b when the voltage at the intermediate node 22c is considered) and R is the resistance of the power resistor 24d.

[0085] The charging time ΔT required to charge from the partially charged voltage V1 to the fully charged voltage V2 is then determined at step 42: ΔT=T2−T1=R⋅C⋅(ln(1−V1Vbatt)−ln(1−V2VBatt)) ΔT=R⋅C⋅ln(Cbatt−V2Vbatt−V1) or: ΔT=C⋅(R⋅(ln(Vbatt−V2)−ln(Vbatt−V1))) and the value of the capacitance C is determined at step 43 according to: C=ΔT / (R⋅(ln(Vbatt−V2)−ln(Vbatt−V1))) or: C=ΔTK(Vbatt) wherein: K(Vbatt)=(R⋅(ln(Vbatt−V2)−ln(Vbatt−V1)))

[0086] In particular, since R, V1 and V2 have preset and known values, complex logarithmic calculations during runtime can be avoided if the values ​​for K at the possible different battery voltages are calculated in advance and stored in a table (which may be contained in the embedded memory 21b of the control unit 21).

[0087] With regard to the accuracy of the capacity estimation by the diagnostic module 28, the following considerations are made with reference to an exemplary case and exemplary values.

[0088] The resistance R may have an absolute accuracy of 5%; in this case, the resistance of the power switch 24c, for example equal to 100 mΩ (this should be added to the resistance R), is much less than the 5% value.

[0089] The time ΔT can have an absolute accuracy of 2% over the entire temperature range due to an internal oscillator tolerance (the oscillator is checked and verified by the control unit 21 in a manner known per se, not discussed in detail here). If the charging of the supercapacitor array 22 is PWM-controlled by the power switch 24c, the charging time ΔT is corrected by multiplying it by the PWM duty cycle.

[0090] Voltage values ​​occur as ratios rather than absolute values, so the absolute accuracy of the voltage measurements does not affect the accuracy of the capacitance estimation.

[0091] The battery voltage V batt must be reduced by the voltage drop across the selection diode 26j; this voltage is small in absolute value and fluctuates within a range of + / - 100 mV for a fixed current. An absolute accuracy of 3% can also be achieved taking into account discretization errors (due to the analog-to-digital conversion at the control unit 21 of the electronic control circuit 10) of the measurement of the battery voltage V batt be assigned.

[0092] The final accuracy of the capacitance value is therefore approximately 10%, by summing 5% for the resistance measurement, 2% for the time measurement, and 3% for the voltage measurement and the discretization error.

[0093] Although the value of the battery voltage V batt is assumed to be constant, it is subject to fluctuations during normal operation while charging the supercapacitor array 22.

[0094] To take this aspect into account, the diagnostic module 28 is configured to detect the variation in the battery voltage V batt and to stop or abort the measurement of the capacity C if there is a deviation of the battery voltage V batt is above a specified threshold for a specified period of time.

[0095] For small deviations of the battery voltage V batt the calculation is carried out using a minimum value V batt (of those determined in the period under consideration) were nevertheless made in order to obtain a lower capacity estimate.

[0096] According to another aspect of the present solution, the equivalent series resistance (ESR) of the supercapacitor group 22 is estimated during operation by the diagnostic module 28 based on the charging method, in particular to check whether it is less than a required maximum value.

[0097] When a charging current is applied, the voltage across the supercapacitor array 22 is increased by the product of the charging current and the equivalent series resistance. In particular, when the charging current is zero, the value of the supercapacitor voltage V sc decrease abruptly with the voltage drop across the equivalent series resistance.

[0098] Using an analog-to-digital converter with a resolution of n bits, for example 10 bits, and a full scale voltage (FS), for example 5 V, the resolution dV for measuring the supercapacitor voltage V sc : dV=FS2n=5210V=5mV

[0099] The above-mentioned AD converter can be implemented in the control unit 21, in particular in the calculation module 21a.

[0100] The nominal value of the ESR can be equal to or less than 100 mΩ, so that the minimum charging current I ch To achieve a resistance resolution dR of, for example, 10 mΩ (1 / 10 of the average value) is: Ich=dVdR=510=500mA

[0101] The resistance R of the power resistor 24d is calculated by the diagnostic module 28 in a first step 50 as follows, as shown in Fig. 5 shown: R=Vbatt−VscIch=12V−5V500mA=14Ω taking into account a minimum value for the ESR determination for the battery voltage V batt and a maximum value for the supercapacitor voltage V sc .

[0102] As described above, the power switch 24c in the charging module 24 may be suitably controlled via a PWM modulation scheme to reduce the power dissipation at the power resistor 24d.

[0103] In this regard, Fig. 6 a possible PWM pattern of the supercapacitor voltage V sc during charging of the supercapacitor group 22, which has an ON phase for each period followed by an OFF phase, the respective duration of which is determined by the duty cycle of the charging activation signal En_ch.

[0104] In this situation, the resistance measurement can advantageously be performed at each period of the charging enable signal En_ch in the OFF phase of the operating cycle (i.e., when the charging current is zeroed due to the opening of the power switch 24c). A suitable average of the various measurements can be implemented to obtain an averaged resulting value.

[0105] Based on the above, the ESR can be determined via the following expression by the diagnostic module 28 at step 51 as shown in Fig. 5 shown, can be determined: ESR=RΔVscVbatt−Vsc where ΔV sc the voltage drop across the supercapacitor group 22 due to the charging current I ch is.

[0106] The diagnostic module 10 is then able to check at step 52 whether the detected ESR value is less than a required value.

[0107] Voltages are used as ratios, so the corresponding accuracy of the AD converter is not relevant for the overall measurement accuracy.

[0108] The measurement tolerance for R is approximately 5% and is reflected in the ESR measurement instead.

[0109] If the voltage accuracy is 0.5%, the total estimation error is expected to be less than 10%

[0110] According to a further aspect of the present solution, the diagnostic module 28 is also configured to consider the temperature conditions under which the e-lock assembly 1 and the supercapacitor array 22 operate. These temperature conditions are monitored by the temperature sensor 29.

[0111] In fact, supercapacitor performance is directly influenced by temperature conditions and operating lifetime.

[0112] As in the Fig. As shown in Figures 7a to 7c, the capacitance of a supercapacitor correlates directly with the lifetime and shows a decrease over time (shown is the relationship between a final value C f and an initial value C i ). In addition, the degree of decrease is determined by the operating temperature and the initial voltage value V i above the supercapacitor.

[0113] Vehicle systems must be able to withstand very high temperatures (for example, up to 70 °C to 100 °C) while ensuring correct operation or at least avoiding failure.

[0114] According to the present solution, the supercapacitor group 22 must provide auxiliary power to allow the user to leave the vehicle in case of malfunctions (e.g., battery, fuse, or wiring malfunctions); at temperatures ranging from 70°C to 100°C, the user cannot remain confined in the motor vehicle 3.

[0115] In order to allow adequate use of the supercapacitor array even at high temperatures, the diagnostic module 28 is therefore configured to implement a suitable sampling strategy for the values ​​of the supercapacitor voltage V sc to implement as the temperature increases (this value is controlled by a suitable modification of the charging process by the charging module 24).

[0116] As in Fig. 8, the diagnostic module 28 accordingly monitors the value of the determined temperature, as shown in step 60.

[0117] The strategy implemented by the diagnostic module 28 then provides three different operating conditions in corresponding temperature ranges: - for temperatures between -Temp1 and +Temp1, step 61, where Temp1 is a first temperature threshold whose absolute value is approximately 38 °C to 42 °C, for example 40 °C: the supercapacitor group 22 is kept fully charged (for example, at a voltage level of each supercapacitor cell 23a, 23b in a range of 2.5 V to 2.7 V), - for temperatures lying between +Temp1 and +Temp2, step 62, where Temp2 is a second temperature threshold whose absolute value is approximately 85°C to 90°C, for example 85°C: a voltage decrease, for example in a linear manner between a first value (for example 2.5 V) and a second value lower than the first (for example 2.1 V), is applied to the supercapacitor voltage V sc made, and - for temperatures higher than +Temp2, step 63: the supercapacitor group 22 is charged up to a supercapacitor voltage V sc a third value which is smaller than the second value (for example 1 V for each supercapacitor cell 23a, 23b).

[0118] According to the above temperature strategy, the decrease of the supercapacitor voltage V sc at higher temperatures, reducing the effect of capacitance changes over time, thereby improving the reliability of the supercapacitor array 22 when used, for example, in the auxiliary power source 20. Furthermore, the lifetime of the supercapacitor array 22 is extended.

[0119] In general, the supercapacitors are available when they are actually needed and an improved lifetime can be achieved; in this respect, it has been shown through simulation that this control strategy allows to achieve at least 15 years of reliable lifetime of the supercapacitor array 22.

[0120] The advantages of the described solution become clear from the above description.

[0121] In particular, a reliable auxiliary power source 20 is provided for vehicle applications, for example, to power the e-lock assembly 1 in the event of a failure of the main power source 4 of the motor vehicle 3 and / or in the event of a disconnection of the e-lock assembly 1 from the same main power source 4.

[0122] The auxiliary power source 20 can be controlled independently of the internal control unit 21 and can also be activated or deactivated without any action by the vehicle main management unit 12 and the relevant control software.

[0123] The use of supercapacitors, in particular a reduced number thereof, and the associated voltage boost circuit may allow the auxiliary power source 20 to be provided in an inexpensive, lightweight and small unit, the resulting size and form factor of the auxiliary power source 20 being such as to allow easy integration within the same housing 11 of the e-lock assembly 1.

[0124] The use of supercapacitors can achieve high energy density, high capacitance, and high output current capability, avoiding memory effects and minimizing power consumption and recharge time. The lifetime of the supercapacitor array is also very high, enabling its use as a reliable auxiliary power source without the need for additional auxiliary power sources.

[0125] The use of low-voltage supercapacitors, for example of the type commonly available on the market, can also make it possible to reduce the cost of the system and improve its maintainability.

[0126] Furthermore, embodiments according to the present description may enable timely diagnosis of a fault of the supercapacitor cells 23a, 23b in the supercapacitor group 22, such as open circuit or short circuit conditions, an increase in a leakage current, an increase in the equivalent series resistance and / or a decrease in the capacitance value.

[0127] The described temperature control strategy may enable supercapacitors to be used reliably as the auxiliary power source 20 even at very high temperatures in order to meet safety requirements, especially those concerning vehicle applications.

[0128] Obviously, changes may be made to that described and illustrated herein without, however, departing from the scope defined by the accompanying claims.

[0129] In particular, the electrical connection of the supercapacitor cells 23a, 23b could be a parallel connection instead of a series connection in order to provide the supercapacitor voltage V required as an auxiliary supply voltage for the actuation group 6' of the motor vehicle 3 sc The number of supercapacitor cells could also vary in case of different size or energy requirements.

[0130] Furthermore, it is emphasized again that the e-lock arrangement 1 can operate any type of different locking devices within the motor vehicle 3.

[0131] During the emergency situation causing the operation of the (external and / or internal) handles 16 of the motor vehicle 3 or, more generally, the opening of the doors 2 to be disabled, this can also be implemented by the control unit 21 by controlling a suitable physical disabling means coupled to the doors 2 and / or the handles 16 and / or the actuation group 6' (the disabling means being configured to mechanically prevent the opening of the same doors 2).

[0132] In general, the auxiliary energy source 20 and the discussed diagnostic and control algorithms for checking the state of the supercapacitor cells 23a, 23b can also be used for other purposes within the motor vehicle 3 for different vehicle applications.

Claims

[1] Electronic lock arrangement (1) for a locking device (2) of a motor vehicle (3), comprising an actuator group (6') operable to control an actuation of the locking device (2), and an electric motor (9) controllable to drive the actuator group (6') and designed to be driven by a main supply voltage (V batt ) providing main power source (4) of the motor vehicle (3), wherein the electronic lock arrangement (1) comprises an auxiliary power source (20) and a control unit (21) configured to control the auxiliary power source (20) to supply the electric motor (9) during a fault operating condition deviating from the normal operating condition, wherein the auxiliary energy source (20) comprises a supercapacitor array (22) configured to store energy during the normal operating condition and to provide an auxiliary supply voltage (V sc ) to supply the electric motor (9), wherein the supercapacitor group (22) comprises a first (23a) and a second (23b) supercapacitor cell connected to each other to jointly generate the auxiliary supply voltage (V sc ), wherein the auxiliary energy source (20) and the control unit (21) are arranged within a housing (11) of the electronic lock arrangement (1), wherein the auxiliary power source (20) further comprises a voltage boost module (26) coupled to the supercapacitor array (22) and configured to boost a level of the auxiliary supply voltage (V sc ) to provide a boost voltage (V boost) designed to supply the electric motor (9), and wherein the auxiliary power source (20) further comprises a balancing module (25) connected to the supercapacitor group (22) and operable to determine a desired voltage level across the first (23a) and second (23b) supercapacitor cells. [2] Electronic lock assembly (1) according to claim 1, wherein the first (23a) and second (23b) supercapacitor cells are of the low voltage / high capacity type and are each adapted to provide a voltage in the range of 2.5 V to 2.7 V and have a capacity in the range of 16 F to 20 F. [3] Electronic lock arrangement (1) according to one of the preceding claims, wherein the auxiliary power source (20) comprises a charging module (24) controllable by the control unit (21) to charge the supercapacitor group (22) during the normal operating condition whenever the main supply voltage (V batt ) is greater than a preset threshold, wherein the charging module (24) comprises a charging resistance element (24d) connected to the supercapacitor group (22) and a resistor connected between a main supply voltage (V batt ) receiving input terminal (24a) and the charging resistance element (24d) and a control terminal, wherein the control unit (21) is configured to provide a charging control signal (En_ch) to the control terminal of the charging switching element (24c) in order to control the charging of the supercapacitor group (22). [4] Electronic lock arrangement (1) according to claim 3, wherein the charging control signal (En_ch) is a pulse width modulated signal which, during the normal operating condition, has an operating cycle defining an ON phase when the supercapacitor group (22) is disconnected from the main supply voltage (V batt ) is charged, and an OFF phase in which the charging of the supercapacitor group (22) is interrupted. [5] Electronic lock arrangement (1) according to one of the preceding claims, wherein the first (23a) and the second (23b) supercapacitor cell are connected in series to supply the auxiliary supply voltage (V sc), wherein the compensation module (25) comprises a first compensation resistance element (25a) designed to be selectively connected in parallel with the first supercapacitor cell (23a) via a first compensation resistance element (25c) controlled by a compensation signal (En_eq) provided by the control unit (21), and a second compensation resistance element (25b) designed to be selectively connected in parallel with the second supercapacitor cell (23b) via a second compensation resistance element (25c) controlled by the compensation signal (En_eq), wherein the compensation signal (En_eq) is designed to selectively interrupt a current flow in the first (25a) and the second (25b) compensation resistance element when the supercapacitor group (22) supplies the electric motor (9) with the auxiliary supply voltage (V sc ) is not provided. [6] Electronic lock assembly (1) according to one of the preceding claims, wherein the boost module (26) comprises a boost voltage converter with an internal controller (26h) and a boost enable switch element (26a) that is selectively activated to turn on the internal controller (26h) to perform the boost operation by an external signal (boost_ON) indicating an external operation on the locking device (2), the internal controller (26h) being configured to maintain the boost operation until it is turned off by the control unit (21) via a turn-off signal (boost_OFF). [7] Electronic lock arrangement (1) according to one of the preceding claims, wherein the auxiliary energy source (20) comprises a diagnostic module (28) connected to the supercapacitor group (22) and configured to determine an operating state of the supercapacitor group (22) by determining at least one value of the auxiliary supply voltage (V sc ), wherein the diagnostic module (28) is configured to detect one or more of the following fault conditions of the supercapacitor group (22): an open circuit fault, a short circuit fault, an increase in a leakage current, an increase in an equivalent series resistance (ESR), a decrease in the capacitance value (C). [8] Electronic lock assembly (1) according to claim 7, wherein the diagnostic module (28) is executed during operation of the e-lock assembly (1) by the control unit (21) and is configured to determine the capacitance value (C) of the supercapacitor group (22) by monitoring the time (ΔT) for charging the supercapacitor group (22) from a preset partial discharge voltage (V1) to a preset full charge voltage (V2) of the auxiliary supply voltage (V sc ) to be estimated. [9] Electronic lock arrangement (1) according to claim 8, wherein the auxiliary power source (20) comprises a charging module (24) controllable by the control unit (21) to charge the supercapacitor group (22) from the main supply voltage (V batt ) via a charging resistance element (24d) with the resistance R, wherein the diagnostic module (28) is configured to estimate the capacitance value (C) of the supercapacitor group (22) via the following expression: C=ΔTK(Vbatt) where K is given by K(Vbatt)=(R⋅(ln(Vbatt−V2)−ln(Vbatt−V1))) and for certain values ​​of the main supply voltage (V batt ) is precalculated and stored in a table in a memory of the control unit (21). [10] Electronic lock assembly (1) according to one of claims 7 to 9, wherein the diagnostic module (28) is executed by the control unit (21) during operation of the e-lock assembly (1) and is configured to estimate the equivalent series resistance (ESR) of the supercapacitor group (22) to check whether it is less than a preset maximum value, wherein the auxiliary power source (20) comprises a charging module (24) controllable by the control unit (21) to charge the supercapacitor group (22) with a charging current (I CH), and the diagnostic module (28) is configured to estimate the equivalent series resistance (ESR) by measuring a voltage drop across the supercapacitor group (22) when charging is interrupted and the charging current (I CH ) is zeroed. [11] Electronic lock arrangement (1) according to claim 10, wherein the charging module (24) is controllable to supply the supercapacitor group (22) with the main supply voltage (V batt ) via a charging resistance element (24d) with a resistance R, wherein the diagnostic module (28) is configured to estimate the equivalent series resistance (ESR) of the supercapacitor group (22) via the following expression: ESR=RΔVSCVbatt−VSC where ΔV sc is the voltage drop across the supercapacitor array (22). [12] Electronic lock arrangement (1) according to claim 10 or 11, wherein the charging module (24) comprises a charging resistor element (24d) connected to the supercapacitor group (22) and a resistor connected between a main supply voltage (V batt ) receiving input terminal (24a) and the charging resistance element (24d) and having a control terminal, wherein the control unit (21) is configured to provide a charging control signal (En_ch) to the control terminal of the charging switching element (24c) to control the charging of the supercapacitor group (22), wherein the charging control signal (En_ch) is a pulse-width modulated signal which, during the normal operating condition, has an operating cycle defining an ON phase when the supercapacitor group (22) is disconnected from the main supply voltage (V batt) is charged, and an OFF phase in which the charging of the supercapacitor group (22) is interrupted, and wherein the diagnostic module (28) is configured to estimate the equivalent series resistance (ESR) of the supercapacitor group (22) during the OFF phase of the operating cycle of the charging control signal (En_ch) when the charging current (I CH ) is zeroed by opening the charge switching element (24c). [13] Electronic lock assembly (1) according to one of the preceding claims, wherein the auxiliary energy source (20) comprises a charging module (24) controllable by the control unit (21) for charging the supercapacitor group (22), and a diagnostic module (28) connected to the supercapacitor group (22) and configured to monitor the operating temperature of the supercapacitor group (22) and to cooperate with the charging module (24) to implement a charging strategy as a function of the measured operating temperature. [14] Electronic lock arrangement (1) according to claim 13, wherein the charging strategy provides three different charging conditions in corresponding temperature ranges, according to which - for temperatures between -Temp1 and +Temp1, the supercapacitor group (22) is kept fully charged, where Temp1 is a first preset temperature value, - for temperatures between +Temp1 and +Temp2, a voltage drop between a first voltage value and a second voltage value, which is lower than the first voltage value, on the auxiliary supply voltage (V sc ), where Temp2 is a second preset temperature value that is higher than the first preset temperature value, and - for temperatures higher than Temp2, the supercapacitor group (22) is discharged to a third voltage value which is lower than the second voltage value. [15] Electronic lock assembly (1) according to claim 14, wherein the first preset temperature value (Temp1) is in the range 38 °C to 42 °C and the second preset temperature value (Temp2) is in the range 85 °C to 90 °C. [16] Electronic lock arrangement (1) according to one of the preceding claims, wherein the fault operating condition includes one of the following faults: a fault of the main power source (4) of the motor vehicle, which supplies the main supply voltage (V batt ), a fault in an electrical connection (5) connecting the electronic lock arrangement (1) to the main power source (4) of the motor vehicle. [17] Motor vehicle (18) with a locking device (2) and an electronic lock arrangement (1) connected to the locking device (2) according to one of the preceding claims.

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