Electronic lock and related energy transfer method
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- ISEO SERRATURE
- Filing Date
- 2024-10-15
- Publication Date
- 2026-06-17
AI Technical Summary
Existing electronic locks suffer from low energy transfer efficiency due to varying inductive coupling between the primary and secondary electrical coils, leading to excess energy supply and a shorter battery lifespan.
The electronic lock system incorporates a primary microcontroller that measures the time for the current in the primary electrical coil to reach a maximum intensity value, using this measurement to regulate and control the cyclically transferred energy, thereby adjusting the clock signal frequency and maximum current intensity.
This solution enhances energy transfer efficiency, prolongs the battery's useful life by minimizing energy wastage, and maintains consistent energy transfer per unit of time regardless of mechanical coupling geometry variations.
Smart Images
Figure EP2024078982_30052025_PF_FP_ABST
Abstract
Description
[0001] ELECTRONIC LOCK AND RELATED ENERGY TRANSFER METHOD
[0002] DESCRIPTION
[0003] The present invention relates to an electronic lock comprising a key and a cylinder equipped with a slot for the insertion of the key, and a method of transferring energy from the key to the cylinder when the key is inserted into the cylinder slot.
[0004] Electronic locks are known in which the key features a primary electronic circuit comprising a primary microcontroller and an autonomous energy source, typically a battery, while the cylinder features a secondary electronic circuit comprising a secondary microcontroller and an energy storage device, typically a capacitor.
[0005] In electronic locks of this type, a system for transferring electrical energy from the battery to the capacitor is provided, usually consisting of a switching power supply that transfers energy through inductive coupling established between a primary electrical coil in the primary electronic circuit and a secondary electrical coil in the secondary electronic circuit when the key is inserted into the cylinder slot.
[0006] More precisely, a primary electronic circuit in the key powers the primary electrical coil with a pulsing current, while the secondary electronic circuit in the cylinder rectifies the induced current and charges the capacitor, which in turn powers circuits and actuators.
[0007] In these known systems, where the inductive coupling between the primary electrical coil and the secondary electrical coil can vary due to the mechanical coupling geometry between the key and the cylinder — caused by the longitudinal and transverse clearance with which the key is positioned in the cylinder slot — the primary electronic circuit always supplies excess energy to compensate for situations where the inductive coupling is weaker.
[0008] Due to the low efficiency of energy transfer, the battery has a shorter lifespan because part of the available energy in the battery is wasted. The technical task of the present invention is, therefore, to create an electronic lock of the aforementioned type that eliminates the technical drawbacks associated with known techniques.
[0009] Within this technical task, one objective of the invention is to create an electronic lock of the aforementioned type that can increase the efficiency of energy transfer and extend the battery’s useful life.
[0010] The technical task, as well as these and other objectives, according to the present invention, are achieved by implementing an electronic lock system comprising a key, a cylinder equipped with a slot for the insertion of the key, a primary electronic circuit mounted on the key and comprising a primary microcontroller, a secondary electronic circuit mounted on the cylinder and comprising a secondary microcontroller, and a switching power supply for the cyclic transfer of electrical energy from the key to the cylinder, where said switching power supply comprises a primary electrical coil inserted in the primary electronic circuit, and a secondary electrical coil inserted in said secondary electronic circuit and inductively coupled to said primary electrical coil when said key is inserted into said slot, characterized by the fact that said primary microcontroller has means for measuring the duration of the time it takes for an electric current circulating in the primary electrical coil to reach a maximum defined intensity value, set parametrically by the primary microcontroller when said key is inserted into said slot, and regulation and / or control means that use said measurement to regulate and / or control the cyclically transferred energy.
[0011] Advantageously, the primary microcontroller is configured to generate a clock signal that defines the start time of each energy transfer cycle.
[0012] Advantageously, said regulation and / or control means comprise a calculation algorithm that uses said measurement as input data and produces as output data a value of the frequency of said clock signal and / or said maximum intensity value of the current. Advantageously, said switching power supply comprises an electronic switch inserted in the primary electronic circuit and switchable between an enabled state and a disabled state for the passage of said electric current through the primary electrical coil.
[0013] The present invention also discloses a method of transferring electrical energy in an electronic lock comprising a key, a cylinder equipped with a slot for the insertion of the key, a primary electronic circuit mounted on the key and comprising a primary microcontroller, a secondary electronic circuit mounted on the cylinder and comprising a secondary microcontroller, and a switching power supply for the cyclic transfer of electrical energy from the key to the cylinder, where said switching power supply comprises a primary electrical coil inserted in the primary electronic circuit, and a secondary electrical coil inserted in said secondary electronic circuit and inductively coupled to said primary electrical coil when said key is inserted into said slot, characterized by the fact of measuring the duration of the time it takes for an electric current circulating in the primary electrical coil to reach a maximum defined intensity value, set parametrically by the primary microcontroller when said key is inserted into said slot, and using said measurement to regulate and / or control the cyclically transferred energy.
[0014] Other features of the present invention are further defined in the following claims. The invention originates from the observation that the geometric coupling configuration between the primary electrical coil and the secondary electrical coil may vary due to the clearance that the key blade has when positioned in the cylinder slot.
[0015] The effect of this variation is also a variation in the mutual inductance value between the primary electrical coil and the secondary electrical coil.
[0016] In particular, there is a decrease in the value of mutual inductance as the distance and axial offset between the primary electrical coil and the secondary electrical coil increase.
[0017] As the value of the mutual inductance changes, the time it takes for the current in the primary electrical coil to reach the predetermined maximum intensity value also changes accordingly. This time is therefore uniquely correlated with and identifies the instantaneous geometric configuration of the coupling between the primary electrical coil and the secondary electrical coil, allowing the switching power supply control parameters to be adjusted according to the changing geometric coupling between the coils.
[0018] The information regarding this time is advantageously used to control and regulate the transferred energy.
[0019] Further features and advantages of the invention will become more evident from the description of a preferred but not exclusive embodiment of the electronic lock according to the invention, illustrated by way of example and not limitation in the accompanying drawings, in which:
[0020] Figure 1 schematically shows the key and the cylinder of the electronic lock;
[0021] Figure 2 shows the circuit diagram of the electronic lock;
[0022] Figures 3 and 4 schematically show methods of regulating energy transfer.
[0023] With reference to the cited figures, the electronic lock system comprises a key 1 and a cylinder 2 equipped with a slot 3 for the insertion of the key 1.
[0024] The electronic lock also comprises a primary electronic circuit 4 mounted on the key 1 , a secondary electronic circuit 5 mounted on the cylinder 2, and a switching power supply for the cyclic transfer of electrical energy from the key 1 to the cylinder 2.
[0025] The primary electronic circuit 4 includes a primary microcontroller 6, and similarly, the secondary electronic circuit 5 includes a secondary microcontroller (not shown).
[0026] The switching power supply includes a primary electrical coil LI inserted in the primary electronic circuit 4, and a secondary electrical coil L2 inserted in the secondary electronic circuit 5 and inductively coupled to the primary electrical coil LI when the key 1 is inserted into the slot 3 of the cylinder 2. The switching power supply also includes an electronic switch M2 inserted in the primary electronic circuit 4 and switchable between an enabled state and a disabled state for the passage of electric current through the primary electrical coil LI.
[0027] The primary electrical coil LI can be embedded in the blade of the key 1, and the secondary electrical coil L2 can be embedded in the rotor of the cylinder 2 adjacent to the slot 3, so that when the key 1 is inserted into the slot 3, the primary electrical coil LI and the secondary electrical coil L2 are positioned with parallel or substantially parallel axes.
[0028] The primary microcontroller 6 is programmed to perform a cyclic transfer of energy from an autonomous energy source, particularly a battery 8, present in the primary electronic circuit 4, to an energy accumulator, particularly a capacitor C5, present in the secondary electronic circuit 5. The primary microcontroller 6 has means for measuring the duration of time that, when the key 1 is inserted into the slot 3, an electric current circulating in the primary electrical coil LI takes to reach a maximum intensity value defined parametrically by the primary microcontroller 6 for each energy transfer cycle, and regulation and / or control means that use this measurement to regulate and / or control the cyclically transferred energy.
[0029] The primary microcontroller 6 is configured to generate a clock signal that defines the start time of each energy transfer cycle, corresponding to the start time of the electric current being sent to the primary electrical coil LI.
[0030] The regulation and / or control means include a calculation algorithm that uses the duration of the aforementioned time as input data and produces as output an updated value of the clock signal frequency and / or the updated maximum intensity value of the electric current.
[0031] The primary microcontroller 6 can be programmed specifically to transfer a constant amount of energy per unit of time.
[0032] Naturally, each measurement is used to adjust the subsequent energy transfer cycles following the one during which the measurement was taken. The switching power supply can be of the Fly-Back type.
[0033] In this case, the Fly-Back includes a Flip-Flop Al and a voltage comparator Ul, and the electronic switch M2 is formed by a Mosfet controlled by the Flip-Flop Al.
[0034] The voltage comparator Ul compares the current voltage across a resistor R14, which is traversed by the current flowing through the primary electrical coil LI, with a reference voltage value to switch the Mosfet 15 from a conductive state to a non-conductive state when the current voltage across the resistor R14 exceeds the reference voltage value.
[0035] The method of transferring electrical energy from the key 1 to the cylinder 2 thus involves performing the aforementioned time duration measurement and using this measurement to control and / or regulate the transferred energy.
[0036] In particular, as mentioned above, the primary microcontroller 6 is programmed to adjust the frequency of the clock signal and / or the maximum intensity value of the current flowing through the primary electrical coil LI.
[0037] The energy transfer cycle occurs in detail as follows.
[0038] The primary microcontroller 6, via an output port 10, sends the clock signal that sets the Flip-Flop Al.
[0039] When set, the Flip-Flop Al sends a signal from its Q output that causes the Mosfet M2 to switch from a non-conductive state to a conductive state.
[0040] The electric current supplied by the battery 8 flows in series through the primary electrical coil LI, the Mosfet M2, and the resistor R14.
[0041] The resistor R14 has one terminal connected to the ground and the other terminal connected to the inverting input of the voltage comparator Ul, whose non-inverting input is maintained at the aforementioned maximum reference voltage, determined by a voltage present at an output port 16 of the primary microcontroller 6 and mediated by a voltage divider comprising resistors R15, R16, R17, and a capacitive filter C8. The intensity of the current flowing through the electrical coil LI progressively increases over time, and consequently, the voltage across the resistor R14 proportionally increases.
[0042] When the voltage at the inverting input of the voltage comparator U1 exceeds the maximum reference voltage at the non-inverting input of the voltage comparator Ul, the voltage comparator U1 resets the Flip-Flop Al by sending a signal to a CLR input of the Flip-Flop Al.
[0043] As a result of the reset, the Flip-Flop Al sends a signal from its Q output that switches the Mosfet M2 from a conductive state to a non-conductive state, and simultaneously sends a signal from its Q- output that is detected by the primary microcontroller 6 through its input port 17.
[0044] The measurement of the time interval between the rising edge of the clock signal that the primary microcontroller 6 sends to the CLK input of Flip-Flop Al, and the rising edge of the signal from the Q- output that the Flip-Flop Al sends to the input port 17 of the primary microcontroller 6, is proportional to the value of the mutual inductance between the primary electrical coil LI and the secondary electrical coil L2.
[0045] When the Mosfet M2 switches from a conductive state to a non-conductive state, the current flow through the primary electrical coil LI stops, and current begins to flow through the secondary electrical coil L2.
[0046] The electric current flowing through the secondary electrical coil L2 charges the capacitor C5 through a diode D6.
[0047] In practice, as long as the Mosfet M2 is in a conductive state, energy is stored in the magnetic field formed by the primary electrical coil LI and the secondary electrical coil L2, and when the Mosfet M2 switches from a conductive state to a non-conductive state, the energy stored in the magnetic field is transferred to the capacitor C5 and from there to a load R6.
[0048] As seen, it is possible to achieve sequential energy transfer packets where the amount of energy transferred per unit of time can be controlled and / or regulated. For example, it can be kept constant by appropriately adjusting the clock signal frequency and / or the maximum current value flowing through the primary electrical coil LI .
[0049] For instance, the measurement of the aforementioned time duration can be used to calculate, with the same maximum current value flowing through the primary electrical coil LI, the clock signal frequency based on the energy to be transferred per unit of time, or to calculate, with the same clock signal frequency, the maximum current value flowing through the primary electrical coil LI based on the energy to be transferred per unit of time.
[0050] Figure 3 shows a first example of energy transfer regulation, where a constant amount of energy is intended to be transferred per unit of time, regardless of the mechanical coupling geometry between the key 1 and the cylinder 2, and consequently, regardless of the mutual inductance value between the primary electrical coil LI and the secondary electrical coil L2.
[0051] In Figure 3, the energy transfer regulation per unit of time is performed by maintaining the maximum current intensity value Imaxl flowing through the primary electrical coil LI constant. The lower graph on the left side shows the time progression of the clock signal, and the upper graph on the left shows schematically the corresponding time progression of the current intensity flowing through the primary electrical coil LI in a specific mechanical coupling configuration, indicated as A, between the key 1 and the cylinder 2.
[0052] In Figure 3, the lower graph on the right side shows the time progression of the clock signal, and the upper graph on the right shows schematically the corresponding time progression of the current intensity flowing through the primary electrical coil LI when the configuration A changes to a configuration B of mechanical coupling between the key 1 and the cylinder 2.
[0053] Assuming that the primary microcontroller 6 settings initially remain unchanged during the transition from configuration A to configuration B, the clock signal initially maintains the frequency vl=l / tl. In configuration B, however, the current intensity rise time in the primary electrical coil LI is faster, indicating a lower mutual inductance value between the primary electrical coil LI and the secondary electrical coil L2.
[0054] The amount of energy transferred with each clock signal pulse in configuration A equals the area of the triangular region defined by vertices a, b, and c.
[0055] The amount of energy transferred with the first clock signal pulse in configuration B, equal to the area of the triangular region defined by vertices a', b', and c', is less than that transferred with each clock signal pulse in configuration A, for example, half the energy amount, as the maximum current value Imaxl is reached in a time T' equal to half the time T required for the electric current to reach the maximum value Imaxl in configuration A (T' = T / 2).
[0056] At this point, the primary microcontroller 6, to maintain the energy transferred per unit of time in configuration B equal to that in configuration A, changes the clock signal frequency to v2, specifically doubling it by setting t2=ti / 2.
[0057] Figure 4 shows a second example of energy transfer regulation, where a constant amount of energy is intended to be transferred per unit of time, regardless of the mechanical coupling geometry between the key 1 and the cylinder 2, and consequently, regardless of the mutual inductance value between the primary electrical coil LI and the secondary electrical coil L2.
[0058] In Figure 4, the energy transfer regulation per unit of time is performed by keeping the clock signal frequency constant and changing the maximum current intensity value Imaxl flowing through the primary electrical coil LI .
[0059] The lower graph on the left side shows the time progression of the clock signal, and the upper graph on the left shows schematically the corresponding time progression of the current intensity flowing through the primary electrical coil LI, again in configuration A of mechanical coupling between the key 1 and the cylinder 2.
[0060] In Figure 4, the lower graph on the right side shows the time progression of the clock signal, and the upper graph on the right shows schematically the corresponding time progression of the current intensity flowing through the primary electrical coil LI once again when configuration A changes to configuration B of mechanical coupling between the key 1 and the cylinder 2. Assuming that the primary microcontroller 6 settings initially remain unchanged during the transition from configuration A to configuration B, at the first clock signal pulse in configuration B, there is once again a faster rise in the current intensity flowing through the primary electrical coil LI, resulting in the amount of energy transferred with the first clock signal pulse in configuration B, equal to the area of the triangular region defined by vertices a', b', and c', being less than that transferred with each clock signal pulse in configuration A, for example, half the energy amount, as the maximum current value Imaxl is reached in a time T' equal to half the time T required for the electric current to reach the maximum value Imaxl in configuration A (T = T / 2).
[0061] At this point, the primary microcontroller 6, to maintain the energy transferred per unit of time in configuration B equal to that in configuration A, changes the maximum current intensity value, raising it from Imaxi to Imax2, so that the amount of energy transferred with each subsequent clock signal pulse in configuration B is the same as that transferred with each clock signal pulse in configuration A.
[0062] The new maximum current value Imax2 is then calculated so that the area of the triangular region defined by vertices a", b", c", which defines the amount of energy transferred with each subsequent clock signal pulse in configuration B, is equal to the area of the triangular region defined by vertices a, b, c, which defines the amount of energy transferred with each clock signal pulse in configuration A.
[0063] The electronic lock thus conceived is susceptible to numerous modifications and variations, all within the scope of the inventive concept; furthermore, all details are replaceable with technically equivalent elements. In practice, the materials used, as well as the dimensions, can be any according to needs and the state of the art.
Claims
CLAIMS1. An electronic lock system comprising a key (1), a cylinder (2) provided with a slot (3) for the insertion of the key (1), a primary electronic circuit (4) mounted on the key (1) and comprising a primary microcontroller (6), a secondary electronic circuit (5) mounted on the cylinder (2) and comprising a secondary microcontroller, and a switching power supply for cyclically transferring electrical energy from the key (1) to the cylinder (2), wherein said switching power supply comprises a primary electrical coil (LI) inserted in the primary electronic circuit (4), and a secondary electrical coil (L2) inserted in said secondary electronic circuit (5) and inductively coupled to said primary electrical coil (LI) when said key (1) is inserted into said slot (3), characterized in that said primary microcontroller (6) has means for measuring the duration of the time it takes for an electric current circulating in the primary electrical coil (LI) to reach a defined maximum intensity value parametrically set by the primary microcontroller (6) when said key (1) is inserted into said slot (3), and means for regulating and / or controlling that use said measurement to regulate and / or control the cyclically transferred energy.
2. An electronic lock system according to the preceding claim, characterized in that the primary microcontroller (6) is configured to generate a clock signal that defines the start time of each energy transfer cycle.
3. An electronic lock system according to the preceding claim, characterized in that said regulating and / or control means comprise a calculation algorithm using said measurement as input data and producing as output data a value of the frequency of said clock signal and / or said maximum current intensity value.
4. An electronic lock system according to any one of claims 2 and 3, characterized in that said switching power supply comprises an electronic switch (M2) inserted in the primaryelectronic circuit (4) and switchable between a state of enabling and a state of prohibiting the passage of said electric current through the primary electrical coil (LI).
5. An electronic lock system according to any one of the preceding claims, characterized in that said primary electronic circuit (4) comprises a battery (8) that supplies said electric current and said secondary electronic circuit (5) comprises a capacitor (C5) for storing the electrical energy supplied by said battery (8).
6. An electronic lock system according to any one of the preceding claims, characterized in that said primary microcontroller (6) is programmed to transfer a constant amount of energy per unit of time.
7. An electronic lock system according to any one of the preceding claims, characterized in that said switching power supply is of the Fly-Back type.
8. An electronic lock system according to the preceding claim, characterized in that said Fly- Back includes a Flip-Flop (Al) and a voltage comparator (Ul), wherein said electronic switch (M2) is formed by a Mosfet controlled by said Flip-Flop (Al), and said voltage comparator (Ul) compares an actual voltage value across a resistor (R14) through which said electric current flows with a reference voltage value in such a way as to switch said Mosfet from a conducting state to a non-conducting state when the actual voltage value exceeds the reference voltage value.
9. A method for transferring electrical energy in an electronic lock system comprising a key (1), a cylinder (2) provided with a slot (3) for the insertion of the key (1), a primary electronic circuit (4) mounted on the key (1) and comprising a primary microcontroller (6), a secondary electronic circuit (5) mounted on the cylinder (2) and comprising a secondary microcontroller, and a switching power supply for cyclically transferring electrical energy from the key (1) to the cylinder (2), wherein said switching power supply comprises a primary electrical coil (LI) inserted in the primary electronic circuit (4), and a secondaryelectrical coil (L2) inserted in said secondary electronic circuit (5) and inductively coupled to said primary electrical coil (LI) when said key (1) is inserted into said slot (3), characterized in that it involves measuring the duration of the time it takes for an electric current circulating in the primary electrical coil (LI) to reach a defined maximum intensity value parametrically set by the primary microcontroller (6) when said key (1) is inserted into said slot (3), and using said measurement to regulate and / or control the cyclically transferred energy.