Non-contact charging control device

Abstract

To provide a non-contact charging control device that can stop charging in time when an abnormality occurs.SOLUTION: A non-contact charging control device includes a ground-side control device 27, which reduces a voltage phase difference between a ground-side transformer 24 and a vehicle-side transformer 31 when a voltage sensor 34 detects an overvoltage of a smoothing capacitor 33.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a contactless charging control device.

Background Art

[0002] Patent Document 1 realizes the operation of transmitting power while ensuring electrical insulation between a first three-phase switching circuit provided on the ground side and a second three-phase switching circuit provided on the vehicle side, and the operation of boosting the voltage by a transformer, thereby simplifying or miniaturizing the circuit of the power conversion device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a contactless charging device such as that of Patent Document 1, when the ground-side inverter controls the charging power, in the event of an abnormality, when releasing the vehicle-side relay that connects the battery and the transformer on the vehicle side during charging, the power from the ground side is charged into the capacitor and becomes an overvoltage. For this reason, in a contactless charging device, in the event of an abnormality, the vehicle side instructs the ground side to stop power supply via wireless communication, but since communication takes time, the charging stop may not be in time and the device may malfunction.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a contactless charging control device capable of stopping charging in the event of an abnormality.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a non-contact charging control device according to the present disclosure is a non-contact charging control device that controls a power receiving device capable of non-contact charging for charging a battery by receiving power non-contact from a power transmission device, including: a power receiving side transformer that receives non-contact AC power having a transmission frequency transmitted from a power transmission side transformer; a rectifier circuit that converts the AC power received by the power receiving side transformer into DC power and outputs the DC power to the battery; a smoothing capacitor provided between the rectifier circuit and the battery to smooth the current from the rectifier circuit; a voltage sensor that detects the voltage of the smoothing capacitor; and a control unit that reduces the voltage phase difference between the power transmission side transformer and the power receiving side transformer when the voltage sensor detects an overvoltage of the smoothing capacitor.

Effect of the Invention

[0007] According to the present disclosure, there is an effect that charging can be stopped during an abnormality.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] Hereinafter, a non-contact charging control device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same. Also, each drawing referred to in the following description only schematically shows the shape, size, and positional relationship to the extent that the content of the present disclosure can be understood. That is, the present disclosure is not limited only to the shape, size, and positional relationship illustrated in each drawing.

[0010] (Embodiment 1) 〔Configuration of Non-Contact Power Transmission System〕 FIG. 1 is a diagram schematically showing the configuration of the non-contact power transmission system according to Embodiment 1. The non-contact power transmission system 1 shown in FIG. 1 includes a power transmission device 2 and a power reception device 3 that are magnetically coupled. In the non-contact power transmission system 1, the power transmission device 2 performs non-contact power transmission of the power from the AC power source 4 to the power reception device 3 by magnetic field coupling.

[0011] 〔Configuration of Power Transmission Device〕 First, the configuration of the power transmission device 2 will be described. The power transmission device 2 is provided on the ground, for example. The power transmission device 2 is electrically connected to an AC power source 4 (for example, a commercial power system) and receives power from the AC power source 4. The power transmission device 2 includes a PFC (Power Factor Correction) circuit 21, a smoothing capacitor 22, an inverter circuit 23, a ground-side transformer 24, a ground-side synchronization signal transformer 25, a ground-side communication unit 26, and a ground-side control device 27.

[0012] The PFC circuit 21 converts the AC power received from the AC power supply 4 into DC power and supplies it to the inverter circuit 23. Further, the PFC circuit 21 is configured to improve the power factor by making the input current approach a sine wave. The PFC circuit 21 is configured by adopting various known circuits. Note that, instead of the PFC circuit 21, a rectifier without a power factor improvement function may be adopted.

[0013] The smoothing capacitor 22 is provided between the PFC circuit 21 and the inverter circuit 23 and smoothes the current from the PFC circuit 21.

[0014] The inverter circuit 23 converts the DC power input from the PFC circuit 21 into power for transmission (AC) having a predetermined transmission frequency and transmits it to the ground-side transformer 24. The inverter circuit 23 is composed of at least a boost capacitor 231, a switching element 232, and a switching element 233.

[0015] One end of the boost capacitor 231 is electrically connected to the switching element 232, and the other end is electrically connected to the switching element 233.

[0016] Each of the switching element 232 and the switching element 233 is electrically connected in series. Also, one end of the switching element 232 is electrically connected to the boost capacitor 231, and the other end is electrically connected to the switching element 233. Further, one end of the switching element 233 is electrically connected to the switching element 232, and the other end is electrically connected to the boost capacitor 231. For each of the switching element 232 and the switching element 233, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), etc. are used.

[0017] The above-ground transformer 24 is a primary coil, and AC power (transmission power) having a transmission frequency received from the inverter circuit 23 is transmitted from the power transmission device 2 to the power reception device 3 through a magnetic field formed between the above-ground transformer 24 and a vehicle-side transformer 31 described later. That is, the above-ground transformer 24 and the vehicle-side transformer 31 are magnetically coupled to form the transformer 5.

[0018] The above-ground synchronization signal transformer 25 is a primary coil, and under the control of the above-ground control device 27, transmits a synchronization signal for coupling with the transformer 5 input from the above-ground control device 27 to a vehicle-side synchronization signal transformer 37 described later. That is, the above-ground synchronization signal transformer 25 and the vehicle-side synchronization signal transformer 37 are magnetically coupled to form the synchronization signal transformer 6.

[0019] The above-ground communication unit 26 performs wireless communication with a vehicle-side communication unit 38 described later under the control of the above-ground control device 27 according to a predetermined communication standard. Here, the predetermined communication standard is Bluetooth (registered trademark), Wi-Fi, etc. The above-ground communication unit 26 is configured using a communication module or the like that can transmit according to the predetermined communication standard.

[0020] The above-ground control device 27 controls each part of the power transmission device 2. The above-ground control device 27 is configured using a processor having hardware such as a memory and a CPU (Central Processing Unit). The above-ground control device 27 controls the on / off operations of the switching element 232 and the switching element 233. Specifically, when the above-ground control device 27 switches the switching element 232 from the off state to the on state, it switches the switching element 233 from the on state to the off state.

[0021] 〔Configuration of the power reception device〕 Next, the configuration of the power receiving device 3 will be described. The power receiving device 3 includes a vehicle-side transformer 31, a rectifier circuit 32, a smoothing capacitor 33, a voltage sensor 34, a relay circuit 35, a battery 36, a vehicle-side synchronization signal transformer 37, a vehicle-side communication unit 38, and a vehicle-side control device 39. In the first embodiment, the power receiving device 3 functions as a non-contact charging control device.

[0022] The vehicle-side transformer 31 is a secondary coil, and receives non-contact AC power (transmission power) having a transmission frequency transmitted from the ground-side transformer 24 of the power transmission device 2 through a magnetic field formed between the ground-side transformer 24. The vehicle-side transformer 31 outputs the received AC power to the rectifier circuit 32.

[0023] The rectifier circuit 32 converts the AC power input from the vehicle-side transformer 31 into DC and outputs it to the battery 36. The rectifier circuit 32 is composed of a boost capacitor 321, a switching element 322, and a switching element 323.

[0024] One end of the boost capacitor 321 is electrically connected to the switching element 322, and the other end is electrically connected to the switching element 323.

[0025] Each of the switching element 322 and the switching element 323 is electrically connected in series. Also, one end of the switching element 322 is electrically connected to the boost capacitor 321, and the other end is electrically connected to the switching element 323. Further, one end of the switching element 323 is electrically connected to the switching element 322, and the other end is electrically connected to the boost capacitor 321. Each of the switching element 322 and the switching element 323 uses an IGBT, a MOSFET, or the like.

[0026] The smoothing capacitor 33 is provided between the rectifier circuit 32 and the battery 36, and smoothes the current from the rectifier circuit 32.

[0027] The voltage sensor 34 detects the voltage of the smoothing capacitor 33 and outputs the detection result to the vehicle-side control device 39. The voltage sensor 34 is connected in parallel to the smoothing capacitor 33.

[0028] The relay circuit 35 is provided between the rectifier circuit 32 and the battery 36. Under the control of the vehicle-side control device 39, the relay circuit 35 is in an on state (closed state) during the charging of the battery 36 by the power transmission device 2, and electrically connects the rectifier circuit 32 and the battery 36. On the contrary, under the control of the vehicle-side control device 39, the relay circuit 35 is in an off state (open state), and electrically disconnects the rectifier circuit 32 and the battery 36.

[0029] The battery 36 is a rechargeable DC power source, and is configured using a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride battery. The battery 36 stores the power input from the rectifier circuit 32 via the relay circuit 35. The battery 36 supplies the stored power to a drive device (not shown) of a motor generator (not shown), etc.

[0030] The vehicle-side synchronous signal transformer 37 is a secondary coil, receives a synchronous signal for coupling with the transformer 5 from the ground-side synchronous signal transformer 25, and outputs the received synchronous signal to the vehicle-side control device 39.

[0031] The vehicle-side communication unit 38 performs wireless communication with the ground-side communication unit 26 according to a predetermined communication standard under the control of the vehicle-side control device 39. The vehicle-side communication unit 38 is configured using a communication module or the like capable of transmitting according to a predetermined communication standard.

[0032] The vehicle-side control device 39 controls each part of the power receiving device 3. The vehicle-side control device 39 is configured by using a processor having hardware such as a memory and a CPU. The vehicle-side control device 39 controls the on / off operations of the switching element 322 and the switching element 323. Further, when the voltage sensor 34 detects an overvoltage of the smoothing capacitor 33, the vehicle-side control device 39 performs control to reduce the voltage phase difference between the ground-side transformer 24 and the power receiving-side transformer 30. Specifically, the vehicle-side control device 39 makes the voltage phase difference between the ground-side transformer 24 and the power receiving-side transformer 30 zero. In the first embodiment, the vehicle-side control device 39 functions as a control unit.

[0033] 〔Main circuit configuration of non-contact power transmission system and equivalent circuit of transformer〕 Next, the main circuit configuration of the non-contact power transmission system 1 and the equivalent circuit of the transformer 5 will be described. FIG. 2 is a main circuit configuration diagram of the non-contact power transmission system 1 described in FIG. 1. FIG. 3 shows the equivalent circuit of the transformer 5. FIG. 4 is a diagram showing an outline of the voltage and current waveforms of each part in the equivalent circuit of FIG. 3.

[0034] As shown in FIGS. 2 to 3, each of the switching element 232 and the switching element 233 of the power transmission device 2 has a freewheeling diode D1, D2 electrically connected in antiparallel. Similarly, each of the switching element 332 and the switching element 323 of the power receiving device 3 has a freewheeling diode D3, D4 electrically connected in antiparallel.

[0035] Further, the equivalent circuit shown in FIG. 3 includes a series inductor 51, a first shunt inductor 52, and a second shunt inductor 53. When the inductance of the ground-side transformer 24 is L and the coupling coefficient between the ground-side transformer 24 and the vehicle-side transformer 31 is k, the inductance L of the series inductor 51 cp is (1 - k 2 )L / K. The inductances Ls of the first shunt inductor 52 and the second shunt inductor 53 are (1 + k)L.

[0036] In this way, in the non-contact power transmission system 1, an induced electromotive force is generated in the first shunt inductor 52 by the switching of the switching element 232 and the switching element 233. The induced electromotive force and the output voltage V of the AC power supply 4 in Based on the boosted voltage V boost1 Is applied to the capacitor C buf1 (Boost capacitor 231). The capacitor C buf1 Is charged by the applied voltage.

[0037] Also, in the non-contact power transmission system 1, an induced electromotive force is generated in the second shunt inductor 53 by the switching of the switching element 322 and the switching element 323. The induced electromotive force and the output voltage V of the battery out Based on the boosted voltage V boost2 Is applied to the capacitor C buf2 (Boost capacitor 321). The capacitor C buf1 Is charged by the applied voltage.

[0038] In the non-contact power transmission system 1, the power P transmitted between the transformers 5 is determined by the duty ratio D of the switching element 232 and the switching element 233 of the power transmission device 2 1 , And the duty ratio D of the switching element 322 and the switching element 323 of the power receiving device 3 2 And the voltage phase difference δ of the transformer voltage of the transformer 5 composed of the ground side transformer 24 and the vehicle side transformer 31. Specifically, in the non-contact power transmission system 1, the power P transmitted between the transformers 5 is expressed by Equation (1).

[0039]

Equation

[0040] Here, the voltage and current of each part in FIGS. 2 and 3 will be described. FIG. 4 is a diagram showing an overview of the voltage and current waveforms of each part in FIGS. 2 and 3. In FIG. 4, the duty ratio D 1 And the duty ratio D 2Shows the results when they are equal and D. The horizontal axis in FIG. 4 indicates the phase (θ [rad]). Also, in FIG. 4, from the upper row, (a) is the voltage V that appears in the ground-side transformer 24 tr1 is shown, and (b) is the voltage V that appears in the vehicle-side transformer 31 tr2 is shown. Further, in FIG. 4, (c) is the boost current i flowing through the first shunt inductor 52 S1 is shown 、 (d) is the boost current i flowing through the second shunt inductor 53 S2 is shown, and (e) is the transmission current i flowing through the series inductor 51 cp is shown. Furthermore, (f) is the current i flowing through the ground-side transformer 24 tr1 is shown, and (g) is the current i flowing through the vehicle-side transformer 31 tr2 is shown. Also, (h) is the current i flowing through the inverter circuit 23 buf1 is shown, and (i) is the current i flowing through the rectifier circuit 32 buf1 is shown.

[0041] As shown in FIG. 4, the non-contact power transmission system 1 can control the power transmission amount by controlling the voltage phase difference δ. That is, in the non-contact power transmission system 1, if the voltage phase difference δ is 0, the charging power becomes 0.

[0042] 〔Control of Voltage Phase Difference δ〕 Next, the power control in the non-contact power transmission system 1 will be described. FIG. 5 is a diagram showing an overview of conventional power control. FIG. 6 is a diagram showing an overview of the power control in the non-contact power transmission system 1. In FIGS. 5 and 6, (a) is the voltage V that appears in the ground-side transformer 24 tr1 is shown, and (b) is the voltage V that appears in the vehicle-side transformer 31 tr2 is shown.

[0043] As shown in Fig. 5, conventionally, the ground-side control device 27 controls the voltage phase difference δ by performing on / off control of the switching elements 232 and 233 of the inverter circuit 23. Specifically, when the relay circuit 35 of the power receiving device 3 (vehicle) is released, the ground-side control device 27 performs on / off control of the switching elements 232 and 233 of the inverter circuit 23 to set the voltage phase difference δ to 0, thereby stopping the charging. However, when an abnormality occurs on the vehicle side or when a stop instruction is transmitted via wireless communication, due to communication delay in wireless communication, a delay time occurs until the ground-side control device 27 performs on / off control of the switching elements 232 and 233 of the inverter circuit 23 to set the voltage phase difference δ to 0.

[0044] Therefore, as shown in Fig. 6, when an abnormality occurs in the vehicle, the vehicle-side control device 39 controls the on / off of the switching elements 322 and 323 of the rectifier circuit 32 to shift the phase on the power receiving device 3 side forward (see arrow A2), thereby controlling the voltage phase difference δ to 0. In this case, the vehicle-side control device 39 controls the on / off of the switching elements 322 and 323 of the rectifier circuit 32 so that the control range of the voltage phase difference δ of the power receiving device 3 (vehicle side) is wider than the control range of the voltage phase difference δ of the power transmission device 2 (see arrow A1). Thereby, the voltage phase difference δ can be controlled without going through wireless communication, so that the power supply can be stopped. Further, even when the power transmission device 2 attempts to control to increase the power further than the current power by feedback control or the like, the charging power can be surely stopped.

[0045] [Processing of the Vehicle-Side Control Unit] Next, the processing executed by the vehicle-side control device 39 will be described. Fig. 7 is a flowchart showing an outline of the processing executed by the vehicle-side control device 39. In Fig. 7, one of the processes started with the activation of the power transmission device 2 of the non-contact power transmission system 1 will be described for the vehicle-side control device 39.

[0046] As shown in FIG. 7, first, the vehicle-side control device 39 acquires the voltage of the smoothing capacitor 33 on the vehicle side detected by the voltage sensor 34 (step S101).

[0047] Subsequently, the vehicle-side control device 39 compares the voltage of the smoothing capacitor 33 on the ground side acquired from the voltage sensor 34 with a preset threshold value, and determines whether the voltage of the smoothing capacitor 33 is an overvoltage (step S102). Specifically, the vehicle-side control device 39 compares the voltage of the smoothing capacitor 33 on the vehicle side acquired from the voltage sensor 34 with a preset threshold value. When the voltage of the smoothing capacitor 33 is equal to or higher than the threshold value, the vehicle-side control device 39 determines that the voltage of the smoothing capacitor 33 is an overvoltage. When the vehicle-side control device 39 determines that the voltage of the smoothing capacitor 33 is an overvoltage (step S102: Yes), the vehicle-side control device 39 proceeds to step S103. On the other hand, when the vehicle-side control device 39 determines that the voltage of the smoothing capacitor 33 is not an overvoltage (step S102: No), the vehicle-side control device 39 returns to step S101.

[0048] In step S103, the vehicle-side control device 39 controls the on / off of the switching elements 322 and 323 of the rectifier circuit 32 to control the transmission phase difference between the ground-side transformer 24 and the vehicle-side transformer 31 to 0. Specifically, when an abnormality occurs in the vehicle, the vehicle-side control device 39 controls the on / off of the switching elements 322 and 323 of the rectifier circuit 32 to shift the phase on the power receiving device 3 side forward, thereby controlling the voltage phase difference δ to 0. In this case, the vehicle-side control device 39 controls the on / off of the switching elements 322 and 323 of the rectifier circuit 32 so that the control range of the voltage phase difference δ of the power receiving device 3 (vehicle side) becomes wider than the control range of the voltage phase difference δ of the power transmission device 2 (see arrow A1).

[0049] Subsequently, the vehicle-side control device 39 determines whether the charging power has become equal to or less than the threshold value based on the voltage of the smoothing capacitor 33 on the vehicle side detected by the voltage sensor 34 (step S104). Specifically, the vehicle-side control device 39 determines whether the charging power has become zero based on the voltage of the smoothing capacitor 33 on the vehicle side detected by the voltage sensor 34. When the charging power has become equal to or less than the threshold value based on the voltage of the smoothing capacitor 33 on the ground side detected by the voltage sensor 34 (step S104: Yes), the vehicle-side control device 39 ends this process. On the other hand, when the charging power has not become equal to or less than the threshold value based on the voltage of the smoothing capacitor 33 on the ground side detected by the voltage sensor 34 (step S104: No), the vehicle-side control device 39 returns to step S103.

[0050] According to the first embodiment described above, when the overvoltage of the smoothing capacitor 33 is detected by the voltage sensor 34 by the vehicle-side control device 39, control is performed to reduce the voltage phase difference δ between the ground-side transformer 24 and the power-receiving side transformer 30, so that charging can be stopped during an abnormality.

[0051] Also, according to the first embodiment, since the vehicle-side control device 39 makes the voltage phase difference δ between the ground-side transformer 24 and the power-receiving side transformer 30 zero, charging can be surely stopped without delay during an abnormality.

[0052] Also, according to the first embodiment, since the vehicle-side control device 39 controls the on / off of the switching element 322 and the switching element 323 of the rectifier circuit 32 so that the control range of the voltage phase difference δ of the power-receiving device 3 becomes wider than the control range of the voltage phase difference δ of the power-transmitting device 2, even when the power-transmitting device 2 tries to increase the power further than the current power by feedback control or the like, the charging power can be surely stopped.

[0053] (Second Embodiment) Next, Embodiment 2 will be described. In Embodiment 1, power was transmitted from the ground side to the vehicle side, but in Embodiment 2, power is transmitted from the vehicle side to the ground side. In the following, after explaining the configuration of the non-contact power transmission system of Embodiment 2, the processes executed by the non-contact power transmission system will be described. Note that the same components as those of the non-contact power transmission system 1 according to Embodiment 1 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0054] 〔Configuration of Non-Contact Power Transmission System〕 FIG. 8 is a diagram schematically showing the configuration of the non-contact power transmission system according to Embodiment 2. The non-contact power transmission system 1A shown in FIG. 8 includes a power transmission device 2A instead of the power transmission device 2 according to Embodiment 1.

[0055] 〔Configuration of Power Transmission Device〕 Next, the configuration of the power transmission device 2A will be described. The power transmission device 2A further includes a relay circuit 28. Further, the power transmission device 2A includes a bidirectional converter 29 and a voltage sensor 100 instead of the PFC circuit 21 according to Embodiment 1. Note that in Embodiment 2, the power transmission device 2A functions as a non-contact charging control device.

[0056] The relay circuit 28 is provided between the bidirectional converter 29 and the inverter circuit 23. The relay circuit 28 is turned on (closed state) under the control of the ground-side control device 27 when charging the battery 36 of the power receiving device 3 by the power transmission device 2A or when discharging the battery 36 of the power receiving device 3, and electrically connects the bidirectional converter 29 and the inverter circuit 23. On the other hand, the relay circuit 35 is turned off (open state) under the control of the ground-side control device 27 when charging of the battery 36 of the power receiving device 3 by the power transmission device 2A is stopped or when discharging of the battery 36 of the power receiving device 3 is stopped, and electrically disconnects the bidirectional converter 29 and the inverter circuit 23.

[0057] The bidirectional converter 29 is electrically connected to the load R1 and is also electrically connected to the inverter circuit 23 via the relay circuit 28. Under the control of the ground-side control device 27, the bidirectional converter 29 functions as a DC power source during charging of the battery 36 of the power receiving device 3 and outputs electric power to the inverter circuit 23. On the other hand, under the control of the ground-side control device 27, the bidirectional converter 29 functions as a DC / AC converter during discharging of the battery 36 of the power receiving device 3, converts the DC input from the inverter circuit 23 into AC, and outputs it to the load R1.

[0058] The voltage sensor 100 detects the voltage of the smoothing capacitor 22 and outputs the detection result to the ground-side control device 27. The voltage sensor 100 is connected in parallel to the smoothing capacitor 22.

[0059] [Processing of the Ground-Side Control Unit] Next, the processing executed by the ground-side control device 27 will be described. Fig. 9 is a flowchart showing an overview of the processing executed by the ground-side control device 27. In Fig. 9, the vehicle-side control device 39 will explain the processing during discharging of the battery 36 of the power receiving device 3.

[0060] As shown in Fig. 9, first, the ground-side control device 27 acquires the voltage of the ground-side smoothing capacitor 22 detected by the voltage sensor 100 (step S201).

[0061] Subsequently, the ground-side control device 27 compares the voltage of the ground-side smoothing capacitor 22 acquired from the voltage sensor 34 with a preset threshold value to determine whether the voltage of the smoothing capacitor 22 is overvoltage (step S202). Specifically, the ground-side control device 27 compares the voltage of the ground-side smoothing capacitor 22 acquired from the voltage sensor 100 with a preset threshold value. When the voltage of the smoothing capacitor 22 is equal to or higher than the threshold value, the ground-side control device 27 determines that the voltage of the smoothing capacitor 22 is overvoltage. When the ground-side control device 27 determines that the voltage of the smoothing capacitor 22 is overvoltage (step S202: Yes), the ground-side control device 27 proceeds to step S203. On the contrary, when the ground-side control device 27 determines that the voltage of the smoothing capacitor 22 is not overvoltage (step S202: No), the ground-side control device 27 returns to step S201.

[0062] In step S203, the ground-side control device 27 controls the on / off of the switching elements 232 and 233 of the inverter circuit 23 to control the transmission phase difference between the ground-side transformer 24 and the vehicle-side transformer 31 to 0. Specifically, when an abnormality occurs in the vehicle, the ground-side control device 27 controls the on / off of the switching elements 232 and 233 of the inverter circuit 23 to delay the phase on the power transmission device 2A side, thereby controlling the voltage phase difference δ to 0. In this case, the ground-side control device 27 controls the on / off of the switching elements 232 and 233 of the inverter circuit 23 so that the control range of the voltage phase difference δ of the power transmission device 2A (ground side) is wider than the voltage phase difference δ of the power receiving device 3 (vehicle side).

[0063] Subsequently, the ground-side control device 27 determines whether the charging power has fallen below a threshold value based on the voltage of the smoothing capacitor 22 on the ground side detected by the voltage sensor 100 (step S204). Specifically, the ground-side control device 27 determines whether the charging power has become zero based on the voltage of the smoothing capacitor 33 on the ground side detected by the voltage sensor 34. When the charging power has fallen below the threshold value based on the voltage of the smoothing capacitor 22 on the ground side detected by the voltage sensor 100 (step S204: Yes), the ground-side control device 27 ends this process. On the other hand, when the charging power has not fallen below the threshold value based on the voltage of the smoothing capacitor 22 on the ground side detected by the voltage sensor 100 (step S204: No), the ground-side control device 27 returns to step S203.

[0064] According to the second embodiment described above, when the ground-side control device 27 detects an overvoltage of the smoothing capacitor 22 by the voltage sensor 100, control is performed to reduce the voltage phase difference δ between the ground-side transformer 24 and the power receiving-side transformer 30, so that charging can be stopped during an abnormality.

[0065] Also, in the degradation prediction device according to an embodiment, the "control unit" described above can be read as a "control circuit", "control means", "control device", etc.

[0066] In the description of the flowchart in this specification, expressions such as "first", "subsequently", "then", etc. are used to clarify the sequence of processing between steps. However, the order of processing required to implement this embodiment is not uniquely determined by these expressions. That is, the order of processing in the flowchart described in this specification can be changed within a non-contradictory range.

[0067] Further effects and modifications can be easily derived by those skilled in the art. The broader aspects of the present invention are not limited to the specific details and representative embodiments described and represented as above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

[0068] As described above in detail with reference to the drawings some embodiments of the present application, these are examples, and the present invention can be implemented in other forms with various modifications and improvements based on the knowledge of those skilled in the art, starting from the aspects described in the disclosure column of the present invention.

Explanation of Reference Numerals

[0069] 1,1A Non-contact Power Transmission System 2,2A Power Transmission Device 3 Power Receiving Device 4 AC Power Source 5 Transformer 6 Synchronization Signal Transformer 21 PFC Circuit 22 Smoothing Capacitor 23 Inverter Circuit 24 Ground Side Transformer 25 Ground Side Synchronization Signal Transformer 26 Ground Side Communication Unit 27 Ground Side Control Device 28 Relay Circuit 29 Bidirectional Converter 30 Power Receiving Side Transformer 31 Vehicle Side Transformer 32 Rectifier Circuit 33 Smoothing Capacitor 34,100 Voltage Sensor 35 Relay Circuit 36 Battery 37 Vehicle Side Synchronization Signal Transformer 38 Vehicle Side Communication Unit 39 Vehicle Side Control Device 231,321 Boost Capacitor 232,233,322,323 Switching Element

Claims

1. A non-contact charging control device for controlling a power receiving device capable of non-contact charging for charging a battery by receiving power non-contact from a power transmission device, a power receiving side transformer that non-contactly receives AC power having a transmission frequency transmitted from a power transmission side transformer, a rectifier circuit that converts the AC power received by the power receiving side transformer into DC and outputs it to the battery, a smoothing capacitor provided between the rectifier circuit and the battery for smoothing the current from the rectifier circuit, a voltage sensor for detecting the voltage of the smoothing capacitor, a control unit that reduces the voltage phase difference between the power transmission side transformer and the power receiving side transformer when the voltage sensor detects an overvoltage of the smoothing capacitor, comprising: a non-contact charging control device.

2. The non-contact charging control device according to claim 1, wherein the control unit sets the voltage phase difference between the power transmission side transformer and the power receiving side transformer to 0. a non-contact charging control device.

3. The non-contact charging control device according to claim 2, wherein the control unit makes the control range of the voltage phase difference of the power receiving side transformer wider than the control range of the voltage phase difference of the power transmission side transformer. a non-contact charging control device.

4. The non-contact charging control device according to claim 3, wherein the rectifier circuit has a plurality of switching elements, and the control unit reduces the voltage phase difference between the power transmission side transformer and the power receiving side transformer by performing on / off control of each of the plurality of switching elements. a non-contact charging control device.

5. The non-contact charging control device according to claim 4, wherein the non-contact charging control device is provided in a vehicle. a non-contact charging control device.

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