Electric field coupled contactless power supply system

Abstract

The circuit remains simple, while maintaining a constant output voltage or output current despite misalignment between the electrodes of the transmitting and receiving pads, and also maintaining soft switching. [Solution] In the electric field-coupled non-contact power supply system, a power transmitting device and a power receiving device are capacitively coupled via first and second electrodes of the power transmitting and receiving pad section. The power transmitting device includes an inverter circuit that converts a DC voltage into an AC voltage by switching and outputs it to the first electrode via an external capacitor, and the first electrode. The power receiving device includes a second electrode and a rectifier circuit that converts the AC voltage received via the second electrode into a DC voltage and outputs it to the load. The inverter circuit ensures that the output voltage or output current output to the load is constant and that the DC voltage is zero-voltage switching (ZVS) or zero-current switching (ZCS), and the capacitance value of the external capacitor is smaller than the capacitance value of the capacitor between the first and second electrodes.

Description

[Technical Field]

[0001] This invention relates to an electric field coupled non-contact power supply system. [Background technology]

[0002] For example, secondary batteries mounted on mobile devices such as automated guided vehicles (AGVs) and autonomous mobile robots (AMRs) are charged using an electric field-coupled contactless power supply system via a power-transmitting pad section (see, for example, Patent Document 1). In this contactless power supply system, one or two pairs of electrodes constituting power-transmitting pad sections are provided in the power-transmitting device and the power-receiving device, respectively, and electrical energy is transmitted using a parallel plate type capacitor when they come close to each other.

[0003] The advantages of this contactless power supply system include the following: (1) It can be formed from a metal plate such as an aluminum plate, making it lightweight and inexpensive. (2) Because the electric field between electrodes is mainly limited to the area between electrodes, leakage flux is low and the influence of metallic foreign matter is small, making it robust in metallic environments. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-040809 [Non-patent literature]

[0005] [Non-Patent Document 1] Kazuma Shinode, et al., "Capacitive Power Transfer System Using a Local-independent Class E Zero Voltage Switching Parallel Resonant Inverter and a Class D Voltage-Driven Rectifier," IEEE Transactions on Circuits and Systems, Vol. 14, No. 8, August 2021. [Non-Patent Document 2] Yutaro Komiyama et al., "Analysis and Design of High-Frequency WPT System Using Load-Independent Inverter With Robustness Against Load Variations and Coil Misalignment," IEEE Access, Vol. 12, pp.23043-23056, 2024 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, considering the practical applications of electric field-coupled contactless power supply systems, it is necessary to maintain constant output characteristics (voltage or current) and high efficiency regardless of the misalignment of the coupling capacitor (transmitting and receiving pad). To achieve this, control feedback (transmitting information from the receiving device to the transmitting device) has generally been used. However, this method has problems such as increased circuit complexity and delays associated with communication control. Therefore, misalignment-independent designs that do not require a control system between the receiving and transmitting devices are attracting attention. Here, since there is no circuit that is robust to the misalignment of the coupling capacitor without control, it was necessary to maintain a constant output voltage and high efficiency against the misalignment of the coupling capacitor without control.

[0007] The object of the present invention is to provide an electric field-coupled non-contact power supply system that, compared to the prior art, does not have a complex circuit, can maintain a constant output voltage or output current even with respect to misalignment between electrodes in the power transmission and reception pad section, and can maintain soft switching of ZVS or ZCS. [Means for solving the problem]

[0008] A field-coupled non-contact power supply system according to one aspect of this disclosure is: An electric field coupled non-contact power supply system in which a power transmission device and a power receiving device are capacitively coupled via first and second electrodes of a power transmission / receiving pad section, The aforementioned power transmission device is An inverter circuit including an external capacitor, which converts a DC voltage into an AC voltage by switching and outputs it to the first electrode via the external capacitor, Including the first electrode, The power receiving device is The electrode of the preceding 2, The system includes a rectifier circuit that converts the AC voltage received through the second electrode into a DC voltage and outputs it to the load, The inverter circuit ensures that the output voltage or output current output to the load remains constant and that the DC voltage is zero-voltage switching (ZVS) or zero-current switching (ZCS). The capacitance value of the external capacitor is set to be smaller than the capacitance value of the capacitor between the first and second electrodes. [Effects of the Invention]

[0009] Accordingly, according to one aspect of the present disclosure, the electric field coupled non-contact power supply system is less complex than the conventional technology, and the output voltage or output current can be kept constant even with respect to misalignment between the electrodes of the power transmission and reception pads. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing an example configuration of an electric field-coupled non-contact power supply system according to Embodiment 1. [Figure 2] This is a block diagram showing an example configuration of an electric field-coupled non-contact power supply system according to Embodiment 2. [Figure 3A] Figure 2 is a graph showing the relationship between the output voltage Vo and the capacitance value Cp for the capacitance value C0 (=(CtCp / (Ct+Cp)) when the capacitance value Ct = 2000 pF and the inductance Lt = 1.42 μH. [Figure 3B] Figure 3A is a table showing an example of a preferred range for the volume ratio Cp / Ct. [Figure 4A] Figure 2 is a graph showing the relationship between the output voltage Vo and the capacitance value Cp for the capacitance value C0 (=(CtCp / (Ct+Cp)) when the capacitance value Ct = 500 pF and the inductance Lt = 2.25 μH. [Figure 4B] Figure 4A is a table showing an example of a preferred range for the volume ratio Cp / Ct. [Figure 5A] Figure 2 is a circuit diagram showing an example configuration of a load-independent E / F class inverter circuit 3A used in an electric field-coupled contactless power supply system. [Figure 5B] Figure 2 is a circuit diagram showing an example configuration of a push-pull load-independent E / F class inverter circuit 3B used in an electric field-coupled contactless power supply system. [Figure 5C] Figure 2 is a circuit diagram showing an example configuration of a load-independent Class E inverter circuit 3C used in an electric field-coupled contactless power supply system. [Figure 5D] Figure 2 is a circuit diagram showing an example configuration of a load-independent Class E inverter circuit 3D used in an electric field-coupled contactless power supply system. [Figure 5E] Figure 2 is a circuit diagram showing an example configuration of a load-independent inverse E class inverter circuit 3E used in an electric field-coupled contactless power supply system. [Figure 5F] Figure 2 is a circuit diagram showing an example configuration of a load-independent inverse Class E inverter circuit 3F used in an electric field-coupled contactless power supply system. [Figure 6A] Figure 2 is a circuit diagram showing an example configuration of a half-bridge current-driven Class D rectifier circuit 5A used in the electric field-coupled contactless power supply system. [Figure 6B] Figure 2 is a circuit diagram showing an example configuration of a full-bridge current-driven Class D rectifier circuit 5B used in the electric field-coupled contactless power supply system. [Figure 6C] Figure 2 is a circuit diagram showing an example configuration of a half-bridge voltage-driven Class D rectifier circuit 5C used in the electric field-coupled contactless power supply system. [Figure 6D] Figure 2 is a circuit diagram showing an example configuration of a full-bridge voltage-driven Class D rectifier circuit 5D used in the electric field-coupled contactless power supply system. [Figure 6E] Figure 2 is a circuit diagram showing an example configuration of a load-independent Class E rectifier circuit 5E used in the electric field-coupled contactless power supply system. [Figure 6F] Figure 2 is a circuit diagram showing an example configuration of a load-independent E / F class rectifier circuit 5F used in the electric field-coupled contactless power supply system. [Figure 7A] This is a circuit diagram showing the configuration of a conventional electric field coupled non-contact power supply system according to Example 1. [Figure 7B] This is a circuit diagram showing the configuration of an electric field-coupled non-contact power supply system according to a modified example of Conventional Example 1. [Figure 8] This is a circuit diagram showing the configuration of a contactless power supply system according to Conventional Example 2. [Modes for carrying out the invention]

[0011] Embodiments and modified examples of the present invention will be described below with reference to the drawings. The same or similar components are denoted by the same reference numerals.

[0012] (Inventor's insights)

[0013] Figure 7A is a circuit diagram (Figure 1 of Non-Patent Document 1) showing the configuration of a conventional electric field coupled non-contact power supply system according to Conventional Example 1 disclosed in Non-Patent Document 1. In Figure 7A, the input DC voltage V in The voltage is switched by the switching element S of the power transmission device, and then rectified and smoothed by the rectifier and smoothing circuit 401 of the power receiving device via the power transmission and receiving pad section 411 to produce the output voltage V.o and is output to the load resistor R. Here, the power transmission / reception pad unit 411 includes two pairs of electrodes (P1, P3; P2, P4) and is configured with the inter-electrode capacitors C 13 , C 24 and the leakage capacitors C 12 , C 34 and can be illustrated by an equivalent circuit including them. The mutual coupling capacitance value C m between the two pairs of electrodes (P1, P3; P2, P4) is expressed by the following equation (see Equation (4) of Non-Patent Document 1).

[0014]

Equation

[0015] Here, the leakage capacitor between electrodes P1 and P4 is C 14 and the leakage capacitor between electrodes P2 and P3 is C 23 In the capacitive coupling non-contact power feeding system of FIG. 7A (FIG. 1(a) of Non-Patent Document 1), the power transmission / reception pad unit 411 is replaced with the circuit 403 of the power transmission / reception pad unit which is the parallel capacitor C1 of capacitors C a , C b , and an equivalent circuit (FIG. 1(e) of Non-Patent Document 1) obtained by replacing the rectifying and smoothing circuit 401 with the load resistor R2 is shown in FIG. 7B. In the equivalent circuit of FIG. 7B, the impedance Z2 when viewing the load resistor R2 from the terminal side of the power transmission / reception pad unit is expressed by the following equation (see Equation (7) of Non-Patent Document 1).

[0016]

Equation

[0017] Here, ω is the driving angular frequency of the switching element S, R1 is the load resistor of the intermediate equivalent circuit from FIG. 7A to FIG. 7B (FIG. 1(d) of Non-Patent Document 1), P r is the output power, and V m is the output voltage.

[0018] As is clear from Equations (1) and (2), the output voltage V mThe mutual coupling capacitance value C of the power transmission / receiving pad section 403 m It depends on the mutual coupling capacity value C. m Since this changes due to the misalignment between electrodes of the power transmission / receiving pad section 403, it does not have characteristics that are independent of misalignment. In other words, the non-contact power supply system according to Conventional Example 1 disclosed in Non-Patent Document 1 has characteristics that are independent of load fluctuations, but does not have characteristics that are independent of misalignment. The embodiments shown below provide a non-contact power supply system that has characteristics that are independent of load fluctuations and characteristics that are independent of misalignment.

[0019] Figure 8 is a circuit diagram showing the configuration of a contactless power supply system according to Conventional Example 2 disclosed in Non-Patent Document 2. The contactless power supply system in Figure 8 comprises a power transmission device 101, a coupling unit 311, and a power receiving device 201. Here, the power transmission device 101 is configured with a load-independent E / F class amplifier, and the coupling unit 311 is configured with series-connected capacitors C1 and C2 and electromagnetically coupled inductors L1 and L2. The power receiving device 201 is configured with a current-driven D class rectifier circuit 211 and a buck converter 212.

[0020] Conventional Example 2 in Figure 8 is characterized by being configured so that the output voltage or output current remains constant, for example, in relation to changes in voltage or current due to the remaining charge or charging of the secondary battery (i.e., load fluctuations).

[0021] (Embodiment 1) In contrast, in Embodiment 1, as shown in Figure 1, the coupling capacitor C of the power transmission / reception pad section 4 p1 ,C p2 (Series capacitance C p= (C p1 ·C p2 ) / (C p1 +C p2 An external capacitor C with a capacitance value small, preferably for example, a sufficiently small capacitance value relative to )). t (C t <C p or C t ≪C pA new concept is introduced in which the coupling capacitor C of the power transmission / receiving pad section 4 is inserted in series. p1 ,C p2 The system is characterized by its independence from misalignment, that is, achieving a constant output voltage or output current, and ZVS or ZCS. In other words, by combining the inverter circuit shown in Figure 8 with this new concept, a contactless power supply system is provided that, compared to conventional technology, does not complicate the circuit and can maintain a constant output voltage or output current in response to both misalignment between the electrodes of the power transmitting and receiving pads and load fluctuations, while also maintaining ZVS or ZCS soft switching.

[0022] Here, "load-independent" refers to a state in which the output voltage or current remains constant even when the load impedance value fluctuates, achieving ZVS (Zero Voltage Switching) or ZCS (Zero Current Switching). This reduces switching losses and makes it possible to maintain high efficiency at high frequencies. In previous research, a load-independent design of an electric field-coupled contactless power supply system using a Class E inverter has been proposed (see, for example, Non-Patent Document 1).

[0023] Figure 1 is a block diagram showing an example configuration of an electric field-coupled contactless power supply system according to Embodiment 1. In Figure 1, the electric field-coupled contactless power supply system comprises a power transmission device 100, a power transmission / receiving pad section 4, and a power receiving device 200. Here, the power transmission device 100 includes a power factor correction circuit (PFC circuit) 2 and an external capacitor C at the termination. t The system is configured with an inverter circuit 3 having a coupling capacitor C, for example, two pairs of electrodes. p1 ,C p2 The system is configured to include the following. The power receiving device 200 is also configured to include a rectifier circuit 5 and a DC-DC converter circuit 6.

[0024] In the electric field-coupled contactless power supply system configured as described above, the AC voltage from the AC power source 1 is converted to a DC voltage and its power factor is improved by the power factor correction circuit 2, and then output to the inverter circuit 3. The inverter circuit 3 converts the input DC voltage to an AC voltage by switching it, for example, using a switching element, and then outputs it to the external capacitor C at the end. t AC power from the power receiving device 200 is transmitted via the power transmission / receiving pad section 4.

[0025] The rectifier circuit 5 of the power receiving device 200 rectifies the input AC voltage into a DC voltage and then outputs it to the DC-DC converter circuit 6. The DC-DC converter circuit 6 converts the input DC voltage into a predetermined DC voltage and then outputs it to the load 7.

[0026] According to the above embodiment 1, as shown in Figure 1, the coupling capacitor C of the power transmission / reception pad section 4 p1 ,C p2 (Series capacitance C p An external capacitor C with a small capacitance value, preferably, for example, a sufficiently small capacitance value, relative to ) t (C t <C p or C t ≪C p ) is inserted in series. This results in the coupling capacitor C of the power transmission / reception pad section 4. p1 ,C p2 This system achieves load-independent characteristics such as a constant output voltage or a constant output current despite misalignment, and maintains ZVS or ZCS soft switching. Furthermore, by using the circuits shown in Figure 8 as the inverter circuit 3 and rectifier circuit 5, a contactless power supply system can be provided that is less complex than conventional technology and can maintain a constant output voltage or output current despite both misalignment between the electrodes of the power transmitting and receiving pads and load fluctuations.

[0027] (Embodiment 2) Figure 2 is a block diagram showing an example configuration of an electric field-coupled contactless power supply system according to Embodiment 2. In Figure 2, the inverter circuit 3 is, for example, a load-independent E / F class inverter circuit, (1) Input inductor L C and, (2) For example, a switching element Q which is an N-channel MOSFET, (3) Shunt capacitor C S and, (4) Inductor L h ,L t And, capacitor C h An LC resonant circuit including, (5) External capacitor C at the end t and, (6) A predetermined switching gate control voltage v gs A control circuit 10 that generates, It includes and is composed of.

[0028] Furthermore, the rectifier circuit 5 is, for example, a half-bridge current-driven Class D rectifier circuit. (1) An LC resonant circuit including capacitors C2 and C3 and inductor L3, (2) A half-bridge rectifier including diodes D1 and D2, (3) Smoothing capacitor C f and, The rectifier circuit 5 rectifies and smooths the AC voltage from the power transmission / receiving pad section 4, and then applies the rectified and smoothed DC voltage to, for example, a load resistor R L Output to load 7.

[0029] The inverter circuit 3 of the contactless power supply system configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using this method for switching, a constant current flows through load 7 or a constant voltage is maintained regardless of the resistance value of load 7, and ZVS or ZCS soft switching is performed.

[0030] Here, the coupling capacitor C of the power transmission / reception pad section 4. p1 ,C p2 (Series capacitance C p An external capacitor C with a small capacitance value, preferably, for example, a sufficiently small capacitance value, relative to ) t (C t <Cp or C t ≪C p ) is inserted in series. This results in the coupling capacitor C of the power transmission / reception pad section 4. p1 ,C p2 This system achieves load-independent characteristics of a constant output voltage or output current despite misalignment, and enables ZVS or ZCS soft switching. Furthermore, by using the circuits shown in Figure 8 as the inverter circuit 3 and rectifier circuit 5, a contactless power supply system can be provided that is less complex than conventional technology and can maintain a constant output voltage or output current despite both misalignment between the electrodes of the power transmitting and receiving pads and load fluctuations.

[0031] Next, the coupling capacitance C of the power transmission / receiving pad section 4 in the contactless power supply system shown in Figure 2. p And the capacitance value C of the external capacitor to be inserted. t An example of the relationship is explained below.

[0032] Figure 3A shows the volume value C in Figure 2. t = 2000pF and inductance L t =1.42μH, the capacity value C0(=(C t C p / (C t +C p Output voltage V for )) o and capacity value C p This graph shows the relationship between the volume value ratio C in Figure 3A. p / C t This table shows an example of a preferred range.

[0033] Figure 4A shows the volume value C in Figure 2. t = 500pF and inductance L t =2.25μH, the volume value C0(=(C t C p / (C t +C p Output voltage V for )) o and capacity value C p This graph shows the relationship between the volume value ratio C in Figure 4A. p / Ct It is a table showing an example of a preferable range.

[0034] In the circuits according to FIGS. 3A and 4A, if the output voltage is within a fluctuation of about 10%, it is considered to be within an acceptable range in practical use, and thus the judgment was made within this range. In addition to the examples shown in FIGS. 3A and 4A, examples when the capacitance value or inductance is changed can also be given. In that case, the coupling capacitance and capacitance value ratio for which the output voltage becomes almost constant will be different values.

[0035] (Modification of the embodiment) In the above embodiment, the power transmission / reception pad unit 4 is, for example, the coupling capacitor C p1 , C p2 composed of a pair of electrode pairs, but the present invention is not limited to this. For example, it may be composed of the coupling capacitor C p composed of a single pair of electrode pairs, or may be composed of a plurality of coupling capacitors C p composed of a plurality of pairs of electrode pairs.

[0036] (Inverter circuit used in the embodiment) The inverter circuit used in the embodiment will be described below. Note that the switching gate control voltages v gs , v gs1 , v gs2 and the like are generated by the control circuit 10.

[0037] FIG. 5A is a circuit diagram showing a configuration example of the load-independent E / F-class inverter circuit 3A used in the electric field coupling type non-contact power feeding system of FIG. 2. In FIG. 5A, the inverter circuit 3A includes (1) an input inductor L I and (2) a switching element Q which is, for example, an N-channel MOSFET, (3) a shunt capacitor C S and (4) an LC resonance circuit including inductors L t , L2 and a capacitor C2, (5) an external capacitor C t and It includes and is composed of.

[0038] The inverter circuit 3A configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using this switching mechanism, a constant current flows through load 7 or a constant voltage is maintained, regardless of the resistance value of load 7, and ZVS or ZCS is performed.

[0039] Figure 5B is a circuit diagram showing an example configuration of a push-pull load-independent E / F class inverter circuit 3B used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 5B, the inverter circuit 3B is: (1) Input inductor L I ,L Ia and, (2) For example, switching elements Q1 and Q2 which are N-channel MOSFETs, (3) Shunt capacitor C S ,C Sa and, (4) Inductor L t ,L2,L 2a and capacitors C2,C 2a An LC resonant circuit including, (5) External capacitor C t and, It includes and is composed of.

[0040] The inverter circuit 3B configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs1 ,v gs2 By using this switching mechanism, a constant current flows through load 7 or a constant voltage is maintained, regardless of the resistance value of load 7, and ZVS or ZCS is performed.

[0041] Figure 5C is a circuit diagram showing an example configuration of a load-independent Class E inverter circuit 3C used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 5C, the inverter circuit 3C is: (1) Input inductor L I and, (2) For example, a switching element Q which is an N-channel MOSFET, (3) Shunt capacitor C S and, (4) Inductor L t and external capacitor C t An LC resonant circuit including, It includes and is composed of.

[0042] The inverter circuit 3C configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using this switching mechanism, a constant voltage is applied to load 7 or a constant current flows through it, and ZVS or ZCS is performed, regardless of the resistance value of load 7.

[0043] Figure 5D is a circuit diagram showing an example configuration of a load-independent Class E inverter circuit 3A used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 5D, the inverter circuit 3D is: (1) Input inductor L I ,L C and, (2) For example, a switching element Q which is an N-channel MOSFET, (3) Inductor L t and capacitor C t An LC resonant circuit including, It includes and is composed of.

[0044] The inverter circuit 3D configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using the inductor L to switch, a constant current flows through load 7 or a constant voltage is maintained regardless of the resistance value of load 7, and ZVS or ZCS is performed. t and capacitor C t An LC resonant circuit including this may be provided in the rectifier circuit 5.

[0045] Figure 5E is a circuit diagram showing an example configuration of a load-independent inverse E-class inverter circuit 3E used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 5E, the inverter circuit 3E is: (1) Input inductor L C and, (2) For example, a switching element Q which is an N-channel MOSFET, (3) Shunt capacitor C S and switching smoothing inductor L S and, (4) Capacitor C1 and, (5) External capacitor C t and termination inductor L t and, It includes and is composed of.

[0046] The inverter circuit 3E configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using this to switch, ZCS is performed so that the voltage across load 7 remains constant regardless of the resistance value of load 7. Note that an external capacitor C is used. t and termination inductor L t It may be provided in the rectifier circuit 5.

[0047] Figure 5F is a circuit diagram showing an example configuration of a load-independent inverse Class E inverter circuit 3F used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 5F, the inverter circuit 3F is: (1) Input inductor L C and, (2) For example, a switching element Q which is an N-channel MOSFET, (3) Shunt inductor L S and the shunt capacitor C (including the parasitic capacitance component of the switching element Q) S Shunt capacitor and, (4) External capacitor C t and termination inductor L t and, It includes and is composed of.

[0048] The inverter circuit 3F configured as described above receives the DC voltage V from the DC power supply 8. I A predetermined switching gate control voltage v gs By using this switching mechanism, a constant current flows through load 7 or a constant voltage is maintained, and ZCS or ZVS is performed, regardless of the resistance value of load 7.

[0049] The inverter circuit shown above is just one example; half-bridge and full-bridge inverters can also be used, regardless of whether they have load-independent characteristics or not.

[0050] (Embodiment ① Rectifier circuit) The rectifier circuit used in the embodiment is described below.

[0051] Figure 6A is a circuit diagram showing an example configuration of a half-bridge current-driven Class D rectifier circuit 5A used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6A, the rectifier circuit 5A is: (1) Inductor L r and capacitor C r An LC resonant circuit including, (2) A half-bridge rectifier including diodes D1 and D2, (3) Smoothing capacitor C f and, It includes and is composed of.

[0052] The rectifier circuit 5A configured as described above rectifies and smooths the AC voltage from the power transmission / reception pad section 4, and then applies the rectified and smoothed DC voltage to, for example, a load resistor R L Output to load 7.

[0053] Figure 6B is a circuit diagram showing an example configuration of a full-bridge current-driven Class D rectifier circuit 5B used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6B, the rectifier circuit 5B is: (1) Inductor L r and capacitor C r An LC resonant circuit including, (2) A full-bridge rectifier including diodes D1 to D4, (3) Smoothing capacitor C f and, It includes and is composed of.

[0054] The rectifier circuit 5B configured as described above rectifies and smooths the AC voltage from the power transmission / reception pad section 4, and then applies the rectified and smoothed DC voltage to, for example, a load resistor R L Output to load 7.

[0055] Figure 6C is a circuit diagram showing an example configuration of a half-bridge voltage-driven Class D rectifier circuit 5C used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6C, the rectifier circuit 5C is: (1) Inductor L r and capacitor C r An LC resonant circuit including, (2) A half-bridge rectifier including diodes D1 and D2, (3) Smoothing inductor L f and smoothing capacitor C f A smoothing circuit including, It includes and is composed of.

[0056] The rectifier circuit 5C configured as described above rectifies and smooths the AC voltage from the power transmission / reception pad section 4, and then applies the rectified and smoothed DC voltage to, for example, a load resistor R L Output to load 7.

[0057] Figure 6D is a circuit diagram showing an example configuration of a full-bridge voltage-driven Class D rectifier circuit 5D used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6D, the rectifier circuit 5D is: (1) Inductor L r and capacitor C r An LC resonant circuit including, (2) A full-bridge rectifier including diodes D1 to D4, (3) Smoothing inductor L f and smoothing capacitor C f A smoothing circuit including, It includes and is composed of.

[0058] The rectifier circuit 5D configured as described above rectifies and smooths the AC voltage from the power transmission / reception pad section 4, and then applies the rectified and smoothed DC voltage to, for example, a load resistor R L Output to load 7.

[0059] Figure 6E is a circuit diagram showing an example configuration of a load-independent Class E rectifier circuit 5E used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6E, the rectifier circuit 5E is: (1) Inductor L r and capacitor C r An LC resonant circuit including, (2) Shunt capacitor C S and, (3) For example, a switching element Q3 which is an N-channel MOSFET, (4) Smoothing inductor L C and smoothing capacitor C f A smoothing circuit including, (5) A predetermined switching gate control voltage v gsa A control circuit 11 that generates, It includes and is composed of.

[0060] The rectifier circuit 5E configured as described above receives the AC voltage from the power transmission / reception pad section 4 via the inductor L r and capacitor C r A switching element Q3 controls the switching gate voltage v via an LC resonant circuit including the LC resonant circuit. gsa After converting to a predetermined AC voltage by switching using a smoothing inductor L C and smoothing capacitor C f The smoothing circuit, which includes the above, smooths the DC voltage to a predetermined DC voltage, and the smoothed DC voltage is then connected to, for example, a load resistor R L Output to load 7.

[0061] Figure 6F is a circuit diagram showing an example configuration of a load-independent E / F class rectifier circuit 5F used in the electric field-coupled contactless power supply system shown in Figure 2. In Figure 6F, the rectifier circuit 5F is: (1) Inductor L r , L2 and capacitor C r , an LC resonant circuit including C2, (2) Shunt capacitor C S and, (3) For example, a switching element Q3 which is an N-channel MOSFET, (4) Smoothing inductor L C and smoothing capacitor C f A smoothing circuit including, (5) A predetermined switching gate control voltage v gsa A control circuit 11 that generates, It includes and is composed of.

[0062] The rectifier circuit 5F configured as described above receives the AC voltage from the power transmission / receiving pad section 4, and the switching element Q3 controls the switching gate voltage v via the LC resonant circuit. gsa After converting to a predetermined AC voltage by switching using a smoothing inductor L C and smoothing capacitor C f The smoothing circuit, which includes the above, smooths the DC voltage to a predetermined DC voltage, and the smoothed DC voltage is then connected to, for example, a load resistor R L Output to load 7.

[0063] (Effects of the embodiment) According to the above embodiment, a large coupling capacitor C in series with the capacitor of the resonant circuit t This was inserted. As a result, the output characteristics become constant regardless of the misalignment between the electrodes of the transmitting and receiving pad section 4 (constant output voltage or constant output voltage), and ZVS or ZCS can be achieved. Furthermore, by combining this with an inverter circuit having load-independent characteristics, both load-independent characteristics and characteristics independent of misalignment can be achieved. From the above, it is possible to achieve constant output characteristics and ZVS or ZCS (hereinafter, both together are referred to as "load-independent characteristics") with respect to misalignment between the electrodes of the transmitting and receiving pad section 4 and load fluctuations without complicating the control wireless communication line or power transmission circuit.

[0064] (modified version) In the above embodiments, the capacitance value C of the external capacitor t This is the capacitance value C between the electrodes.p Preferably, it is set to be sufficiently small so that it becomes smaller, but the present invention is not limited to this, and may be configured so that the capacity value is not set. That is, the capacity value C p and C t The relative magnitudes of the two values ​​do not need to be a constraint. Here, the capacitance value C of the external capacitor. t It is configured to have sufficiently low impedance at the driving frequency and to block DC voltages. Furthermore, it does not require, for example, the insertion of an external capacitor.

[0065] Furthermore, considering the practical applications of electric field-coupled contactless power supply systems, it is necessary to maintain constant output characteristics (voltage or current) and high efficiency regardless of misalignment of the coupling capacitor (transmitting / receiving pad) or load fluctuations (changes due to battery level or charging). To achieve these, control feedback (transmitting information from the receiving device to the transmitting device) has generally been used. However, this method has challenges such as circuit complexity and delays associated with communication control. Therefore, load-independent design, which does not require a control system between the receiving and transmitting devices, is attracting attention. In this design method, load-independent operation is achieved by tuning the element values ​​to meet the load-independent conditions.

[0066] In the embodiments described above, the circuit is not more complex than in the prior art, and the output voltage or output current is kept constant in response to misalignment between the electrodes of the transmitting and receiving pads and modulation of the load, while maintaining soft switching of ZVS or ZCS. However, the present invention is not limited to these embodiments, and load independence does not need to be achieved. The circuit may be less complex than in the prior art, and the output voltage or output current may be kept constant in response only to misalignment between the electrodes of the transmitting and receiving pads, while maintaining soft switching of ZVS or ZCS. Therefore, load independence may or may not be present. [Industrial applicability]

[0067] As described in detail above, the present invention provides an electric field-coupled non-contact power supply system that, compared to the prior art, does not require a complex circuit, maintains a constant output voltage or output current despite misalignment between electrodes in the power transmission and reception pad section, and maintains soft switching of ZVS or ZCS. [Explanation of Symbols]

[0068] 1 AC power supply 2 Power factor correction circuit (PFC circuit) 3. Inverter Circuit 4. Power transmission and reception pad section 5 Rectifier circuit 6 DC-DC converter circuit 7 Load 8 DC power supply 10,11 Control circuits 100, 100A power transmission equipment 200,200A power receiving equipment C0, C1, C2, C 2a ,C3,C f ,C h ,C p1 ,C p2 ,C r ,C S ,C Sa ,C t Capacitor D1~D4 Diodes L1, L2, L 2a ,L3,L C ,L f ,L I ,L Ia ,L r ,L t ,L h Inductor Q, Q1, Q 2, Q3 Switching element R L resistance

Claims

1. An electric field coupled non-contact power supply system in which a power transmission device and a power receiving device are capacitively coupled via first and second electrodes of a power transmission / receiving pad section, The aforementioned power transmission device is An inverter circuit including an external capacitor, which converts a DC voltage into an AC voltage by switching and outputs it to the first electrode via the external capacitor, Including the first electrode, The power receiving device is The first electrode 2, The system includes a rectifier circuit that converts the AC voltage received through the second electrode into a DC voltage and outputs it to the load, The inverter circuit ensures that the output voltage or output current output to the load remains constant and that the DC voltage is zero-voltage switching (ZVS) or zero-current switching (ZCS). The capacitance value of the external capacitor is set to be smaller than the capacitance value of the capacitor between the first and second electrodes. Electric field coupled contactless power supply system.

2. The inverter circuit further ensures that the output voltage or output current output to the load remains constant, regardless of the resistance value of the load, and performs zero-voltage switching (ZVS) or zero-current switching (ZCS) of the DC voltage. The electric field coupled non-contact power supply system according to claim 1.

3. Instead of the inverter circuit having the external capacitor, the rectifier circuit converts the AC voltage received via the second electrode and the external capacitor into a DC voltage and outputs it to the load. The electric field coupled non-contact power supply system according to claim 1 or 2.

4. The first and second electrodes include two pairs of electrode pairs. The two pairs of electrodes include first and second capacitors. The first and second capacitors are connected in series with each other. The electric field coupled non-contact power supply system according to claim 1 or 2.

5. The power transmission device further includes a power factor correction circuit provided in front of the inverter circuit, which converts AC voltage to DC voltage. The power receiving device further includes a DC-DC converter circuit provided between the rectifier circuit and the load, which converts the DC voltage from the rectifier circuit into a predetermined DC voltage. The electric field coupled non-contact power supply system according to claim 1 or 2.

6. The ratio of the capacitance value of the capacitor between the first and second electrodes to the capacitance value of the external capacitor is between 2.5 and 5. The electric field coupled non-contact power supply system according to claim 1 or 2.

7. The ratio of the capacitance value of the capacitor between the first and second electrodes to the capacitance value of the external capacitor is between 6 and 20. The electric field coupled non-contact power supply system according to claim 1 or 2.

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