Arrangement for the inductive transmission of electrical energy from a primary coil to a secondary winding and method for operating such an arrangement

Abstract

Arrangement for the inductive transfer of electrical energy from a primary coil to a secondary winding, wherein a capacitor (Cres) of a series circuit, which has the secondary coil and a controllable inductor (Lvar), is connected in parallel, wherein the voltage applied to the capacitor (Cres) is supplied to the AC-side terminal of a rectifier, from whose DC-side terminal a load is supplied, wherein the arrangement includes a means for detecting the voltage applied to the capacitor (Cres), wherein the voltage value detected by the means is supplied to the control unit (3) as the actual value, wherein the control unit (3) regulates the actual value to a setpoint value by supplying a control current to the controllable inductance (Lvar), the series circuit consists of the secondary coil and the controllable inductance (Lvar), wherein the primary winding is supplied with an alternating current (IAC) of constant frequency by a current source, wherein a capacitor (C1) is connected in series to the primary winding such that the resonant frequency of the resonant circuit thus formed corresponds to the frequency of the alternating current (IAC), wherein the control unit (3) is designed such that after starting, if there is a control deviation, i.e., a difference between the setpoint U_setpoint and the actual value U_actual, the control current is gradually increased until the control deviation disappears or changes its sign, where, when the sign changes, the direction of the increment is also inverted, wherein the control unit (3) is an MPP controller or a VPP controller.

Description

[0001] The invention relates to an arrangement for the inductive transmission of electrical energy from a primary coil to a secondary winding and a method for operating such an arrangement.

[0002] It is generally known that energy can be transferred inductively via a transformer.

[0003] From EP 1 661 244 B1, a device for contactless energy transmission is known as the closest prior art.

[0004] From DE 10 2014 015 644 A1 a method for inductive energy transfer from a primary winding to a secondary winding is known.

[0005] A method for contactless energy transmission is known from DE 100 53 373 A1.

[0006] The invention is therefore based on the objective of further developing an arrangement for inductive energy transfer, whereby a load is to be optimally supplied.

[0007] According to the invention, the problem is solved in the arrangement according to the features specified in claim 1 and in the method according to the features specified in claim 5.

[0008] Important features of the invention for the arrangement for the inductive transmission of electrical energy from a primary coil to a secondary winding are that a capacitor of a series circuit, which has the secondary coil and a controllable inductor, is connected in parallel, wherein the voltage applied to the capacitor is supplied to the AC-side terminal of a rectifier, from whose DC-side terminal a load is supplied, wherein the arrangement includes a means for detecting the voltage applied to the capacitor, wherein the voltage value detected by the means is supplied to the control unit as the actual value, wherein the control unit regulates the actual value to a setpoint value by supplying a control current to the controllable inductance, in particular wherein the series connection consists of the secondary coil and the controllable inductor.

[0009] The advantage here is that the load can be supplied with an optimal power supply, in particular a specified target voltage or power. Thus, the load, especially in purely resistive designs, can be supplied with the voltage specified by the target value.

[0010] In an advantageous configuration, the load is a resistive load and / or incorporates an energy storage device, such as a rechargeable battery and / or accumulator. The advantage here is that energy can be stored, allowing the mobile unit to move autonomously on the system's operating surface after the energy storage device has been charged.

[0011] According to the invention, the control unit is an MPP controller or a VPP controller, in particular where the control unit regulates the detected voltage to a maximum value, In particular, the maximum value is limited to a specific operating range. An advantage of this approach is that a simple control method can be used to set the optimal resonant frequency and thus also the quality factor.

[0012] According to the invention, the primary winding is supplied with an alternating current of constant frequency from a current source, In particular, a capacitor is connected in series with the primary winding such that the resonant frequency of the resulting resonant circuit corresponds to the frequency of the alternating current. An advantage of this is that a current source, i.e., an alternating current source, can be used. Thus, the secondary winding also exhibits current source-like behavior.

[0013] In a preferred embodiment, the secondary winding, including the rectifier and control unit, is arranged on a mobile unit that is movable on a base on which the primary winding is located. An advantage of this design is that the mobile unit can be charged with energy at a position of optimal coupling and, after charging, can be moved along the platform. Alternatively, the mobile unit can also be designed as a rail vehicle.

[0014] Important features of the procedure for operating an arrangement are that the arrangement is provided for the inductive transfer of electrical energy from a primary coil to a secondary winding, wherein a capacitor of a series circuit, which has the secondary coil and a controllable inductor, is connected in parallel, wherein the voltage applied to the capacitor is supplied to the AC-side terminal of a rectifier, from whose DC-side terminal a load is supplied, where the voltage applied to the capacitor is measured, wherein a control current is supplied to the controllable inductance such that the detected voltage value is regulated as the actual value to a setpoint value, in particular wherein the series connection consists of the secondary coil and the controllable inductor.

[0015] The advantage here is that a simple control method can be used to provide an optimal voltage to a load.

[0016] According to the invention, an MPP control method or a VPP control method is used for the control process. An advantage of this is that a simple control method can be used.

[0017] In an advantageous embodiment, the primary winding is supplied with an alternating current of constant frequency, In particular, a capacitor is connected in series with the primary winding such that the resonant frequency of the resulting resonant circuit corresponds to the frequency of the alternating current. An advantage of this is that tuning to resonance is easily accomplished.

[0018] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0019] The invention will now be explained in more detail with the help of illustrations: In the Fig. Figure 1 shows the inductive charging of a mobile unit 2 that can be moved on a moving surface, in particular the floor, of a system.

[0020] For charging, the handset 2 is located in a primary winding relative to a stationary primary winding arranged on the ground, which has an inductance of L_1k and in Fig.1 the idealized primary side of the transformer, i.e., transformer, T includes, position of optimal inductive coupling.

[0021] A capacitor C1 is connected in series with the primary winding, and the resulting series circuit is driven by an alternating current I_AC from a current source. The resonant frequency of the resonant circuit formed by the primary winding and the capacitor C1 is equal to the frequency of the impressed alternating current I_AC.

[0022] The secondary winding is preferably arranged on the underside of the handset 2, i.e. on the side of the handset 2 facing the primary winding.

[0023] The system therefore has a travel surface on which a handset 2 can be moved. The handset 2 has a secondary winding 5 on its underside. A primary winding is arranged on the travel surface.

[0024] Once the handset 2 has reached a position of optimal inductive coupling between the primary winding and the secondary winding, energy is transferred inductively and a memory of the handset 2 is charged.

[0025] For this purpose, the secondary winding, which has the secondary side of the transformer T and the inductance L_22, is connected in series with a controllable inductance L_var and a capacitor C_res is connected in parallel to the series circuit thus formed.

[0026] The voltage applied to the capacitor C_res is smoothed by means of a single-phase bridge rectifier (D1, D2, D3, D4) and the subsequent choke L3 as well as the smoothing capacitor C and made available to the load R, in particular a resistive load.

[0027] By means of a control current supplied by the control unit 3, the inductance is controlled to such a value that the resonant frequency of the parallel resonant circuit formed from the capacitance C_res and the inductances of the secondary winding and the controllable inductance corresponds to the frequency of the primary-side impressed current I_AC of the current source when the detected voltage U_actual supplied to the load falls below a setpoint U_setpoint.

[0028] The control unit 3 therefore controls the controllable inductance L_var depending on the time course of the difference between the detected actual value of the voltage supplied to the load R and the setpoint U_setpoint.

[0029] The control unit 3 is preferably implemented as an MPP controller, i.e., as a maximum power point controller, or as a maximum voltage point controller. This is because if the load R is essentially a resistive load, adjusting the control current to the state with maximum voltage across the load R is equivalent to adjusting the control current to the state with maximum power across the load R.

[0030] The control current is preferably implemented as direct current and flows through a winding whose magnetic field at least partially saturates the coil core of another winding of the controllable inductance L_var.

[0031] After startup, if a control deviation exists (i.e., a difference between the setpoint U_set and the actual value U_actual), the control current is increased, preferably incrementally, until the control deviation disappears or changes its sign. If the sign changes, the direction of the increase is also inverted. Thus, the control current always moves towards the point at which the setpoint voltage is most closely approximated.

[0032] In another embodiment of the invention, a different rectifier is used instead of the bridge rectifier. Reference symbol list 1 stationary part 2 mobile part 3 Control unit C1 capacity Cres capacity C capacity D1 Diode D2 diode D3 diode D4 diode L1k primary-side inductance L22 Secondary winding Lvar controllable inductance L3 throttle R load resistance T transformer U_ist Actual voltage U_Set Target voltage IAC alternating current, supplied by the power source

Claims

[1] Arrangement for the inductive transfer of electrical energy from a primary coil to a secondary winding, wherein a capacitor (Cres) of a series circuit, which has the secondary coil and a controllable inductor (Lvar), is connected in parallel, wherein the voltage applied to the capacitor (Cres) is supplied to the AC-side terminal of a rectifier, from whose DC-side terminal a load is supplied, wherein the arrangement includes a means for detecting the voltage applied to the capacitor (Cres), wherein the voltage value detected by the means is supplied to the control unit (3) as the actual value, wherein the control unit (3) regulates the actual value to a setpoint value by supplying a control current to the controllable inductance (Lvar), the series circuit consists of the secondary coil and the controllable inductance (Lvar), wherein the primary winding is supplied with an alternating current (IAC) of constant frequency by a current source, wherein a capacitor (C1) is connected in series to the primary winding such that the resonant frequency of the resonant circuit thus formed corresponds to the frequency of the alternating current (IAC), wherein the control unit (3) is designed such that after starting, if there is a control deviation, i.e., a difference between the setpoint U_setpoint and the actual value U_actual, the control current is gradually increased until the control deviation disappears or changes its sign, where, when the sign changes, the direction of the increment is also inverted, wherein the control unit (3) is an MPP controller or a VPP controller. [2] Arrangement according to claim 1, characterized by that the load is a resistive load and / or has an energy storage device, such as an accumulator and / or battery. [3] Arrangement according to at least one of the preceding claims, characterized by , that the control unit (3) regulates the detected voltage to a maximum value. [4] Arrangement according to at least one of the preceding claims, characterized by , that the secondary winding together with rectifier and control unit (3) is arranged on a mobile unit which is movable on a floor on which the primary winding is arranged. [5] Method for operating an order according to at least one of the preceding claims, wherein the arrangement is provided for the inductive transmission of electrical energy from a primary coil to a secondary winding, wherein a capacitor (Cres) of a series circuit, which has the secondary coil and a controllable inductor (Lvar), is connected in parallel, wherein the voltage applied to the capacitor (Cres) is supplied to the AC-side terminal of a rectifier, from whose DC-side terminal a load is supplied, where the voltage applied to the capacitor (Cres) is measured, wherein a control current is supplied to the controllable inductance (Lvar) such that the detected voltage value is regulated as the actual value to a setpoint value, the series circuit consists of the secondary coil and the controllable inductance (Lvar), wherein the primary winding is supplied with an alternating current (IAC) of constant frequency by a current source, wherein a capacitor (C1) is connected in series to the primary winding such that the resonant frequency of the resonant circuit thus formed corresponds to the frequency of the alternating current (IAC), where, after starting, if a control deviation exists (i.e., a difference between the setpoint U_set and the actual value U_actual), the control current is gradually increased until the control deviation disappears or changes its sign. where, when the sign changes, the direction of the increment is also inverted, where an MPP control procedure or a VPP control procedure is executed during the adjustment process. [6] Method according to claim 5, characterized by , that the primary winding is supplied with an alternating current (IAC) of constant frequency.

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