Power supply system in travel

Abstract

A traveling power supply system (10) is provided with: a power receiving unit (30) that is provided to an automatic transport vehicle (50) and that is provided with a power receiving coil (L2), a power receiving-side resonant capacitor (C2) that resonates together with the power receiving coil (L2), and a rectifier circuit (32) that is an ACDC converter; and a power supply unit (20) including a high-frequency inverter (22) that is connected to the DC power source and that has a power supply coil (L1) that is magnetically coupled to the power reception coil (L2) when the automatic transport vehicle (50) approaches, a switching element (SW) that is connected in series to the power supply coil (L1), and a power supply-side resonant capacitor (C1) that resonates together with the power supply coil (L1). The power supply unit (20) wirelessly supplies power to the power receiving unit (30) during the travel of the automatic transport vehicle (50).

Description

Technical Field

[0001] This disclosure relates to a moving power supply system for supplying power to an automated guided vehicle (AGV) in motion. Background Technology

[0002] Previously, a power supply system for powering a moving automated guided vehicle (AGV) has been proposed (see, for example, Patent Document 1).

[0003] In the power supply system described in Patent Document 1, a pre-power supply check is performed before formally supplying power from the power supply unit to the power receiving unit. During this check, with the power supply-side control unit fixing the effective value of the inverter circuit's output voltage to a predetermined first voltage and the power receiving-side control unit fixing the input voltage of the DC-DC converter to a predetermined second voltage, the power receiving-side control unit checks the power supply power supplied from the power supply unit to the power receiving unit. If the power supply power reaches or exceeds a predetermined power level, the power supply unit begins formal power supply. This allows for proper charging of the battery connected to the output of the DC-DC converter.

[0004] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 7243450 Summary of the Invention

[0005] The problem that the invention aims to solve However, the technology in Patent Document 1, such as the control that "starts the power supply device to officially supply power when the power supply reaches or exceeds a predetermined power level," requires feedback control that detects the position of the automated guided vehicle and controls the start / stop of the power supply device based on the detected position of the automated guided vehicle. In other words, it requires detecting the position of the automated guided vehicle and starting / stopping the power supply system while it is in motion based on the position of the automated guided vehicle, which complicates the control process.

[0006] Furthermore, in the technology of Patent Document 1, the primary and secondary circuits of the DC-DC converter each require multiple switching elements to form a bridge, which also leads to the problem of increased size and cost of the power supply system during operation.

[0007] Therefore, the purpose of this disclosure is to provide a power supply system for use while on the move that does not necessarily require feedback control and whose size and cost are suppressed.

[0008] Methods for solving problems To achieve the above objectives, one embodiment of the present disclosure provides a power supply system for movement, comprising: a power receiving unit disposed on an automated guided vehicle (AGV), the power receiving unit having a power receiving coil, a power receiving-side resonant capacitor resonating with the power receiving coil, and an AC-DC converter; and a power supply unit including a high-frequency inverter connected to a DC power supply, having a power supply coil magnetically coupled to the power receiving coil when the AAV approaches, a switching element connected in series with the power supply coil, and a power supply-side resonant capacitor resonating with the power supply coil, wherein the power supply unit wirelessly supplies power to the power receiving unit during the movement of the AAV.

[0009] Invention Effects This disclosure enables the provision of a power supply system for on-the-go applications that does not necessarily require feedback control and whose size and cost are minimized. Attached Figure Description

[0010] Figure 1A This is a circuit diagram illustrating the power supply system during travel in the implementation method.

[0011] Figure 1B This is a diagram illustrating the circuit characteristics of the power supply system during travel in the implementation method.

[0012] Figure 2 This is an explanation Figure 1A The diagram shows the operation of the power supply system during travel.

[0013] Figure 3 This is a diagram illustrating a power supply system in motion, equivalent to a prior art reference example.

[0014] Figure 4 This is a graph that compares and illustrates the distance dependence of the output voltage of the power supply system during travel in the implementation method and reference example.

[0015] Figure 5A This is a block diagram illustrating the configuration of the power supply system during travel in the first variation of the implementation method.

[0016] Figure 5B It indicates composition Figure 5A The circuit diagram of a pair of power supply units and a power receiving unit in the moving power supply system.

[0017] Figure 6A This is a block diagram illustrating the configuration of the power supply system during travel in a second variation of the implementation method.

[0018] Figure 6B It indicates composition Figure 6A The circuit diagram of the power supply unit of the power supply system during movement.

[0019] Figure 6C It indicates composition Figure 6AThe circuit diagram of the power receiving unit of the power supply system during movement.

[0020] Figure 7A This is a block diagram illustrating the configuration of the power supply unit in the power supply system during travel of the third variation of the implementation method.

[0021] Figure 7B It means Figure 7A The circuit diagram of the power supply unit is shown.

[0022] Figure 8A This is a block diagram illustrating the configuration of the power receiving unit in the power supply system during travel in the third variation of the implementation method.

[0023] Figure 8B It means Figure 8A The circuit diagram of the power receiving unit is shown. Detailed Implementation

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the embodiments described below represent specific examples of the present disclosure. The numerical values, circuit components, the arrangement and connection methods of the circuit components, signal timing, control steps, etc., shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, the figures are not strictly illustrative. In the figures, substantially identical configurations are given the same reference numerals, and repeated descriptions are omitted or simplified. Moreover, "A and B connected" means that A and B are electrically connected, including not only the case where A and B are directly connected, but also the case where A and B are indirectly connected with other circuit components between them.

[0025] Figure 1A This is a circuit diagram illustrating the on-the-go power supply system 10 of the embodiment. Here, not only is a representative on-the-go power supply system 10 shown (…), but also… Figure 1A The circuit diagram of (a) also shows the power supply system 10-1 to 10-3 in motion of the modified examples. Figure 1A The circuit diagrams for (b) to (d) are shown. In addition, the energy storage element 51, which is a peripheral component related to the power supply system 10, 10-1 to 10-3 in motion, is also shown.

[0026] like Figure 1A As shown in (a), the moving power supply system 10 is a contactless (i.e. wireless) power supply system that supplies power to the moving automated guided vehicle, and consists of a power supply unit 20 that supplies power and a power receiving unit 30 installed on the automated guided vehicle that receives power supplied from the power supply unit 20.

[0027] like Figure 1AAs shown in (a), the power receiving unit 30 is a unit installed on the automated guided vehicle. It includes a power receiving coil L2, a power receiving side resonant capacitor C2 connected in series with the power receiving coil L2, and a rectifier circuit 32, which is an example of an AC-DC converter. The AC power received from the power supply unit 20 is converted into DC power by the rectifier circuit 32 and output to the energy storage element 51 via the output terminals 31a and 31b. Here, the power receiving coil L2 and the power receiving side resonant capacitor C2 form a series resonant circuit. Alternatively, it can be as follows: Figure 1A As shown in (b) and (d), the receiving unit 30-1 is configured as a parallel resonant circuit in which the receiving coil L2 and the receiving-side resonant capacitor C2 are connected in parallel. In this case, compared with the case of configuring a series resonant circuit, it becomes a configuration suitable for high voltage and low current output.

[0028] like Figure 1A As shown in (a), the power supply unit 20 includes a high-frequency inverter 22 connected to a DC power supply (not shown) via input terminals 21a and 21b. It has a power supply coil L1 magnetically coupled to the receiving coil L2 when the automated guided vehicle approaches, switching elements SW such as a MOSFET connected in series with the power supply coil L1, and a power supply-side resonant capacitor C1 connected in parallel with the power supply coil L1. The power supply unit 20 wirelessly supplies power to the receiving unit 30 during the movement of the automated guided vehicle.

[0029] Here, as Figure 1A As shown in (a), the power supply coil L1 and the power supply-side resonant capacitor C1 form a parallel resonant circuit. Furthermore, the high-frequency inverter 22 does not have multiple switching elements forming a bridge as in the past, but is a single-ended circuit using only one switching element SW for DC-AC conversion. Alternatively, it can also be as follows... Figure 1A As shown in (c) and (d) of the power supply unit 20-1, the power supply side resonant capacitor C1 is connected in parallel with the switching element SW, thereby forming a parallel resonant circuit of the power supply coil L1 and the power supply side resonant capacitor C1.

[0030] In addition, in this embodiment, the smoothing capacitor Cin is connected between the input terminals 21a and 21b, but the smoothing capacitor Cin is not necessary.

[0031] Figure 1BThis is a diagram illustrating the circuit characteristics of the power supply system 10 in motion according to the embodiment. Here, the distance between the power supply coil L1 and the receiving coil L2 (coil position) is used as the horizontal axis, the output power of the power supply system 10 in motion is used as the left vertical axis, and the coupling coefficient k between the power supply coil L1 and the receiving coil L2 is used as the right vertical axis to represent the circuit characteristics (i.e., distance dependence) of the power supply system 10 in motion. Furthermore, regardless of the distance between the power supply coil L1 and the receiving coil L2, the switching frequency of the switching element SW remains fixed. That is, the frequency of the AC power supplied by the power supply unit 20 remains fixed.

[0032] according to Figure 1B As can be seen from the output power characteristics shown, in the moving power supply system 10 of this embodiment, the output power reaches its maximum when the power supply coil L1 and the receiving coil L2 are closest (when the distance on the horizontal axis is zero), and decreases as the distance between the power supply coil L1 and the receiving coil L2 increases. Based on this characteristic, even if the switching frequency of the switching element SW is kept constant, the output power reaches its maximum when the automated guided vehicle is closest to the power supply unit 20, and decreases as the automated guided vehicle moves away from the power supply unit 20, thus obtaining an effective output power characteristic.

[0033] Figure 2 This is an explanation Figure 1A The diagram shows the operation of the power supply system 10 during travel. More specifically, Figure 2 (a) represents Figure 1A The voltage and current symbols in the high-frequency inverter 22 shown in (a) are... Figure 2 (b) indicates Figure 2 The timing of voltage and current, etc., as shown in (a). That is to say, in Figure 2 In (b), “SW” represents the switching state of the switching element SW, “Isw” represents the current flowing through the switching element SW, “Vc1” represents the voltage across the resonant capacitor C1 on the power supply side, “IL1” represents the current flowing through the power supply coil L1, and “Iin” represents the current input from the DC power supply (not shown) to the high-frequency inverter 22.

[0034] As shown in the switching state (“SW”) of the switching element SW, the switching element SW is currently turned on during period (i) and turned off during period (ii), repeatedly switching. Here, period T1, which corresponds to period (ii), is the period corresponding to the resonant frequency of the parallel resonant circuit formed by the power supply coil L1 and the power supply-side resonant capacitor C1. The period T2, which is the sum of periods (i) and (ii), is the period corresponding to the resonant frequency of the series resonant circuit formed by the power receiving coil L2 and the power receiving-side resonant capacitor C2.

[0035] like Figure 2 As shown, in the power supply system 10 during travel of this embodiment, the power supply unit 20 converts the input DC power into AC power through the switching element SW, and applies it to the parallel resonant circuit composed of the power supply coil L1 and the power supply-side resonant capacitor C1, thereby wirelessly supplying power to the power receiving unit 30. Then, the power receiving unit 30 receives the AC power wirelessly supplied from the power supply unit 20 through the series resonant circuit composed of the power receiving coil L2 and the power receiving-side resonant capacitor C2, converts it into DC power through the rectifier circuit 32, and supplies it to the energy storage element 51.

[0036] Figure 3 This is a diagram illustrating a power supply system 110 in motion, equivalent to a prior art reference example. More specifically, Figure 3 (a) is a circuit diagram showing the power supply system 110 in motion for the reference example. Figure 3 (b) is a diagram showing the circuit characteristics of the power supply system 110 in motion in the reference example. Figure 3 (a) and (b) correspond to the embodiments respectively. Figure 1A and Figure 1B .

[0037] like Figure 3 As shown in (a), the power supply system 110 in the reference example consists of a power supply unit 120 and a power receiving unit 130. The power receiving unit 130 includes a receiving coil L2, a receiving-side resonant capacitor C2 connected in series with the receiving coil L2, and a rectifier circuit 132, which is an example of an AC-DC converter. After the AC power received from the power supply unit 120 is converted into DC power by the rectifier circuit 132, it is output to the energy storage element 151 via the output terminals 131a and 131b. Here, the receiving coil L2 and the receiving-side resonant capacitor C2 form a series resonant circuit.

[0038] The power supply unit 120 is an inverter that converts the DC input voltage Vin input via input terminals 121a and 121b into AC. It consists of four switching elements SW1 to SW4 forming a full bridge and a series resonant circuit consisting of a power supply coil L1 and a power supply side resonant capacitor C1 driven by the four switching elements SW1 to SW4.

[0039] like Figure 3As shown in (b), unlike the power supply system 10 in the embodiment, in the power supply system 110 in the reference example, the output power increases as the distance between the power supply coil L1 and the receiving coil L2 increases. Furthermore, the switching frequencies of the switching elements SW1 to SW4 remain fixed regardless of the distance between the power supply coil L1 and the receiving coil L2 (i.e., the resonant frequency of the series resonant circuit formed by the power supply coil L1 and the power supply-side resonant capacitor C1). In other words, the frequency of the AC power supplied by the power supply unit 120 remains fixed.

[0040] Figure 4 This is a graph comparing and illustrating the distance dependence of the output power of the power supply system during travel in the implementation method and reference example. In other words, it is illustrated together. Figure 1B The distance dependence of the output voltage of the power supply system 10 during travel in the illustrated embodiment (the curve in the "Implementment") and Figure 3 The distance dependence of the output voltage of the power supply system 110 during travel is shown in (b) of the reference example (the curve of the "reference example"). Here, as shown in the lower part of this figure, the frequency of the AC power supplied by the power supply unit remains constant.

[0041] according to Figure 4 As can be seen from the curve of the "Implementation Method", in the power supply system 10 during the journey of the implementation method, the output power reaches its maximum when the automated guided vehicle is closest to the power supply unit, and the output power decreases as the automated guided vehicle moves away from the power supply unit. On the other hand, according to Figure 4 As can be seen from the curve of the “reference example”, in the power supply system 110 during the movement of the reference example, the output power is the lowest when the automated guided vehicle is closest to the power supply unit, and the output power increases as the automated guided vehicle moves away from the power supply unit.

[0042] exist Figure 4 In the example, by comparing the output power of the automated guided vehicle in areas far from the power supply unit, it can be seen that when the inverter of the power supply unit is driven at a fixed frequency, the output power is high in the traveling power supply system 110 of the reference example, leading to over-power supply. However, in the traveling power supply system 10 of the embodiment, the output power is automatically suppressed. Therefore, it can be seen that the traveling power supply system 110 of the reference example requires feedback control to detect the position of the automated guided vehicle and control the start / stop of the power supply device based on the detected position, while the traveling power supply system 10 of the embodiment does not require such feedback control.

[0043] Figure 5AThis is a block diagram showing the configuration of the on-the-go power supply system 10a in the first modified embodiment. In addition, the peripheral components related to the on-the-go power supply system 10a (AC power supply 40, ACDC converter 41, automated guided vehicle 50, energy storage element 51) are also shown in this figure.

[0044] like Figure 5A As shown, the power supply system 10a in this modified example consists of multiple power supply units 20a and 20b installed at multiple locations on the ground or track 45 forming the travel path of the automated guided vehicle 50, and a power receiving unit 30a mounted on the automated guided vehicle 50.

[0045] Furthermore, in power supply units 20a and 20b, the power supply coil L1 and the high-frequency inverter 22 are illustrated separately, but this is only for ease of explanation; the power supply coil L1 is a constituent element included in the high-frequency inverter 22. In addition, each of the multiple power supply units 20a and 20b has the same configuration. The following description of power supply units 20a and 20b will use power supply unit 20a as an example.

[0046] Figure 5B It indicates composition Figure 5A The circuit diagram of a pair of power supply units 20a and power receiving units 30a in the on-the-go power supply system 10a is shown in the figure. The peripheral components related to the on-the-go power supply system 10a (AC power supply 40, AC-DC converter 41, and energy storage element 51) are also illustrated in this figure. The AC power supply 40 and the AC-DC converter 41 constitute a DC power supply that supplies DC voltage to the high-frequency inverter 22.

[0047] like Figure 5A and Figure 5B As shown, in the on-the-go power supply system 10a of this modified example, the power supply unit 20a wirelessly supplies AC power to the power receiving unit 30a with a DC voltage supplied from an AC power source 40 and an AC-DC converter 41 that converts AC voltage to DC voltage as input. In addition to the high-frequency inverter 22 consisting of a power supply coil L1, a switching element SW, and a power supply-side resonant capacitor C1 as shown in the embodiment, the power supply unit 20a in this modified example also includes a proximity sensor 23 and a control circuit 24. Furthermore, the DC voltage input to the power supply unit 20a may not be obtained by converting AC voltage.

[0048] The proximity sensor 23 is a sensor that detects the proximity of the automated guided vehicle 50 to the power supply coil L1. Examples include a camera capturing images of the automated guided vehicle 50, a ranging device measuring the distance to the automated guided vehicle 50, an antenna detecting the intensity of electromagnetic waves emitted by the automated guided vehicle 50, and a receiver receiving the current position of the automated guided vehicle 50. Furthermore, the proximity sensor 23 is not a necessary component of the power supply system 10a during operation and may not be included in the power supply system 10a during operation.

[0049] The control circuit 24, when the proximity sensor 23 is installed, controls the high-frequency inverter 22 (more specifically, the switching element SW) to wirelessly supply power from the power supply unit 20a to the power receiving unit 30a based on the detection output of the proximity sensor 23 during the movement of the automated guided vehicle 50. For example, it consists of a memory holding the program, a processor executing the program, and a drive circuit for driving the switching element SW. The control circuit 24, for example, controls the switching element SW to switch at a substantially fixed frequency only when the proximity sensor 23 detects that the automated guided vehicle 50 has entered a certain distance range. On the other hand, when the proximity sensor 23 does not detect that the automated guided vehicle 50 has entered a certain distance range, the control circuit 24 stops the switching of the switching element SW. Here, "substantially fixed frequency" means a substantially fixed frequency; in other words, it is... Figure 4 The distance dependence of the output voltage in the power supply system 10 during travel in the illustrated embodiment is achieved within a range of frequencies, for example, a range in which a variation of 30%, preferably 20%, more preferably 10%, and even more preferably 5% is allowed relative to a certain frequency.

[0050] Furthermore, when the power supply system 10a is not equipped with a proximity sensor 23 during travel, the control circuit 24 controls the switching element SW to switch at a roughly fixed frequency regardless of the position of the automated guided vehicle 50.

[0051] Here, the DC power supply that supplies DC voltage to the power supply unit 20a (i.e., the DC power supply consisting of AC power supply 40 and AC-DC converter 41) can be a pulsating power supply. That is, the DC power supply can be a pulsating power supply consisting of a rectifier stack that rectifies the AC voltage supplied from AC power supply 40 and a filter capacitor that makes the output voltage from the DC power supply pulsate to a certain degree. In this case, the control circuit 24 drives the switching element SW with a drive signal that is frequency-modulated to suppress the high-order harmonics of the current generated in the high-frequency inverter 22 driven by the pulsating power supplied from the DC power supply. For example, the control circuit 24 switches the switching element SW at a low instantaneous power frequency during periods of low instantaneous voltage in the pulsating voltage input to the high-frequency inverter 22, and switches the switching element SW at a high instantaneous power frequency during periods of high instantaneous voltage in the pulsating voltage input to the high-frequency inverter 22, thereby suppressing the high-order harmonics of the current generated in the high-frequency inverter 22.

[0052] The automated guided vehicle 50 is a mobile robot, namely AGV (automated guided vehicle), that carries out unmanned transport along a pre-defined transport path, or a mobile robot, namely AMR (automated guided robot), that determines its own travel path and carries out transport. It is equipped with a power receiving unit 30a and an energy storage element 51 that is charged by DC power output from the power receiving unit 30a.

[0053] In addition to the series resonant circuit consisting of the receiving coil L2 and the receiving-side resonant capacitor C2 shown in the embodiment, the power receiving unit 30a in this modified example also includes a rectifier circuit 32, which serves as an example of an AC-DC converter that rectifies the AC voltage output from the series resonant circuit into a DC voltage. The rectifier circuit 32 is, for example, a diode bridge, and outputs the rectified DC voltage to the energy storage element 51. Alternatively, the rectifier circuit 32 may also be a synchronous rectifier circuit composed of a bridge based on switching elements such as MOSFETs.

[0054] With this modified power supply system 10a, which operates while in motion, the proximity sensor 23 can be used to control the start / stop of power supply units 20a and 20b, thus providing more efficient power to the automated guided vehicle 50 compared to the embodiments described above. Furthermore, the power receiving unit 30a includes a rectifier circuit 32, enabling the power receiving unit 30a to charge the energy storage element 51.

[0055] Furthermore, in the power supply system 10a during travel in this modified example, the receiving unit 30a is composed of a series resonant circuit, but it can also be composed of a parallel resonant circuit. The power supply coil L1 is installed on the ground or the track 45, but it can also be installed on a wall or ceiling, etc., as long as it can be magnetically coupled with the receiving coil L2, and can be installed in any location.

[0056] Figure 6A This is a block diagram illustrating the configuration of the moving power supply system 10b in the second variation of the embodiment. As shown in this figure, the moving power supply system 10b of this variation consists of a power supply unit 20c and a power receiving unit 30b mounted on the automated guided vehicle 50a. Furthermore, only one power supply unit 20c is shown in this figure, but similar to the moving power supply system 10a of the first variation, other power supply units with the same configuration as the power supply unit 20c can be installed at multiple locations on the ground or track 45.

[0057] Figure 6B It indicates composition Figure 6A The circuit diagram of the power supply unit 20c of the power supply system 10b during travel. Figure 6C It indicates composition Figure 6A The circuit diagram of the power receiving unit 30b of the power supply system 10b during movement. Figure 6B and Figure 6C In the power supply unit 20c, one or more power supply coils L1a, L1b, etc. are provided, and in the power receiving unit 30b, one or more power receiving coils L2a, L2b, etc. are provided. In addition, the power receiving unit 30b is composed of a series resonant circuit, but it can also be composed of a parallel resonant circuit.

[0058] The power supply system 10b in this variant basically possesses the same capabilities as... Figure 5A and Figure 5B The power supply system 10a in the first modified example shown has the same configuration. However, this modified example differs from the first modified example in that the power supply unit 20c has multiple power supply coils L1a and L1b connected in parallel, while the power receiving unit 30b has multiple power receiving coils L2a and L2b connected in parallel. More precisely, in the power supply unit 20c, a high-frequency inverter 22 has multiple power supply coils L1a and L1b connected in parallel, while in the power receiving unit 30b, multiple power receiving coils L2a and L2b connected in parallel are connected to a rectifier circuit 32.

[0059] In this modified example of the power supply system 10b during travel, since multiple power supply coils L1a and L1b are provided in one power supply unit 20c, the coupling time between the power supply coil group and the receiving coil group during one pass of the automated guided vehicle 50 is longer compared with the first modified example, thus increasing the total power transmitted.

[0060] Figure 7A This is a block diagram illustrating the configuration of the power supply unit 20d included in the power supply system during travel in the third variation of the implementation method. Figure 7B It means Figure 7A The circuit diagram of power supply unit 20d is shown.

[0061] like Figure 7A and Figure 7B As shown, the power supply unit 20d in this modified example has multiple high-frequency inverters 22a to 22c. Furthermore, in this modified example, each of the multiple high-frequency inverters 22a to 22c has one power supply coil L1a to L1c. Alternatively, a single high-frequency inverter may have two or more power supply coils.

[0062] In addition, Figure 7A and Figure 7B In this embodiment, the power supply unit 20d can also have a proximity sensor 23 and a control circuit 24, as in the first and second modifications described above, and perform the same control as in the first modification. In this modification, the control circuit 24 performs the same drive control on the three high-frequency inverters 22a to 22c in parallel.

[0063] Figure 8A It means Figure 7A The diagram shows the configuration of the power receiving unit 30c, which is the power receiving unit 30c included in the power supply system during travel in the third variation of the embodiment. Figure 8B It means Figure 8A The circuit diagram of the power receiving unit 30c is shown.

[0064] like Figure 8A and Figure 8B As shown, the power receiving unit 30c of this modified example has multiple series resonant circuits composed of multiple power receiving coils L2a to L2c, and multiple rectifier circuits 32a to 32c corresponding to each of the multiple series resonant circuits. The outputs of the multiple rectifier circuits 32a to 32c are connected to a storage element 51 provided by the automated guided vehicle 50. In addition, the power receiving unit 30c is composed of series resonant circuits, but it can also be composed of parallel resonant circuits.

[0065] like Figure 7A , Figure 7B , Figure 8A and Figure 8B As shown, the power supply unit 20d and the power receiving unit 30c of this modified example have multiple power supply coils L1a to L1c and multiple power receiving coils L2a to L2c, which is the same as the second modified example described above. However, the power supply unit 20d and the power receiving unit 30c have multiple high-frequency inverters 22a to 22c and multiple rectifier circuits 32a to 32c, which is different from the second modified example described above.

[0066] Due to these characteristics, the power supply system in this modified example, compared to the first modified example, increases the coupling time between the power supply coil group and the receiving coil group during a single pass of the automated guided vehicle 50 by constructing multiple coils, thereby increasing the total transmitted power. Compared to the second modified example, the parallel connection of high-frequency inverters in the power supply unit stabilizes the power transmitted by each coil.

[0067] The power supply system 10 in the above embodiment includes: a power receiving unit 30, which is installed on the automated guided vehicle 50 and includes a power receiving coil L2, a power receiving side resonant capacitor C2 that resonates with the power receiving coil L2, and a rectifier circuit 32 as an AC-DC converter; and a power supply unit 20, which includes a high-frequency inverter 22 connected to a DC power supply and has a power supply coil L1 that is magnetically coupled to the power receiving coil L2 when the automated guided vehicle 50 approaches, a switching element SW connected in series with the power supply coil L1, and a power supply side resonant capacitor C1 that resonates with the power supply coil L1. The power supply unit 20 wirelessly supplies power to the power receiving unit 30 during the movement of the automated guided vehicle 50.

[0068] Therefore, by providing a power supply unit 20 with a single switching element SW, it is possible to achieve the characteristic that the output power is maximized when the automated guided vehicle 50 is closest to the power supply unit 20, and decreases as the automated guided vehicle 50 moves away from the power supply unit 20. Thus, a moving power supply system 10 can be realized that does not necessarily require feedback control, and whose size and cost are suppressed.

[0069] Here, similar to the first variation, the power supply unit 20a may also include: a proximity sensor 23 to detect the proximity of the automated guided vehicle 50 to the power supply coil L1; and a control circuit 24 to control the switching element SW to wirelessly supply power from the power supply unit 20 to the power receiving unit 30 during the movement of the automated guided vehicle 50, based on the detection output of the proximity sensor 23. Thus, by starting / stopping the power supply according to the position of the automated guided vehicle 50, power can be supplied to the automated guided vehicle 50 more efficiently.

[0070] Alternatively, as in the second and third modifications, the power supply unit 20c may have multiple power supply coils L1a to L1c. Similarly, as in the second and third modifications, the power receiving unit 30b may have multiple power receiving coils L2a to L2c. This increases the coupling time between the power supply coil group and the power receiving coil group during a single pass of the automated guided vehicle 50, thus increasing the amount of power that can be supplied to the automated guided vehicle 50 passing near the power supply unit 20c.

[0071] Alternatively, as described in the first variation, the DC power supply can be a pulsating power supply consisting of a rectifier stack that rectifies the AC power supply 40 and a filter capacitor of a degree that makes the output voltage pulsating. In this case, the control circuit 24 can also drive the switching element SW of the high-frequency inverter 22, which is driven by the pulsating power supplied from the DC power supply, using a drive signal that is frequency-modulated to suppress the high-order harmonics of the AC power supply current. Therefore, it is not necessary to provide a large-capacity capacitor to smooth the DC voltage output from the DC power supply, and unwanted electromagnetic radiation caused by the generation of high-order harmonics of the current can be suppressed.

[0072] Alternatively, as described in the first variation, the control circuit 24 can drive the switching element SW at a roughly fixed frequency during the period when the automated guided vehicle 50 passes a position close to the power supply coil L1. This allows for more efficient power supply by supplying power to the automated guided vehicle 50 only during periods when power is needed.

[0073] Furthermore, as described in the third variation, the power receiving unit 30c has multiple rectifier circuits 32a to 32c, and multiple power receiving coils L2a to L2c are respectively connected to the multiple rectifier circuits 32a to 32c. The outputs of the multiple rectifier circuits 32a to 32c are connected to a power storage element 51 provided by the automated guided vehicle 50. As a result, the coupling time between the power supply coil group and the power receiving coil group during one pass of the automated guided vehicle 50 is increased, thereby increasing the total power transmitted.

[0074] Furthermore, as described in the third variation, multiple power supply coils L1a and L1b are respectively connected to multiple high-frequency inverters 22a and 22b. During the period when the automated guided vehicle 50 passes a position close to the multiple power supply coils L1a and L1b, the control circuit 24 drives multiple switching elements SW of the multiple high-frequency inverters 22a and 22b at a substantially fixed frequency. Thus, by connecting the high-frequency inverters in parallel, the power transmission of each coil can be stabilized.

[0075] The above description of the power supply system in motion based on the embodiments and modifications of this disclosure is provided, but this disclosure is not limited to these embodiments and modifications. Various modifications conceived by those skilled in the art to these embodiments and modifications, or other configurations by combining some of the constituent elements of the embodiments and modifications, are also included within the scope of this disclosure, provided they do not depart from the spirit of the disclosure.

[0076] For example, in the first to third variations described above, the proximity sensor 23 may not necessarily be installed in the power supply system during movement. In this case, the control circuit 24 may control the switching element SW to switch at a substantially fixed frequency regardless of the position of the automated guided vehicle 50.

[0077] Industrial applicability This disclosure can be used as a power supply system for powering moving automated guided vehicles, such as a system for powering AGVs or AMRs.

[0078] Marker description 10, 10a, 10b, 10-1, 10-2 Power supply system during movement Power supply units 20, 20a~20d, and 20-1 21a, 21b Input Terminals 22, 22a~22c, 22-1 High-frequency inverters 23 Proximity Sensor 24 Control Circuit Cin smoothing capacitor L1, L1a~L1c power supply coils C1 Power supply side resonant capacitor SW switching element 30, 30a~30c, 30-1 Power receiving unit 31a, 31b Output terminals 32, 32a~32c rectifier circuits L2, L2a~L2c receiving coils C2 Resonant capacitor on the receiving side Vin input voltage 40 AC power supply 41 ACDC Converter 45. Ground or track 50, 50a Automated Guided Vehicle 51. Energy storage components.

Claims

1. A power supply system for use while in motion, comprising: A power receiving unit, mounted on an automated guided vehicle, includes a power receiving coil, a power receiving-side resonant capacitor that resonates with the power receiving coil, and an AC-DC converter; and The power supply unit includes a high-frequency inverter connected to a DC power supply, and has a power supply coil that is magnetically coupled to the receiving coil when the automated guided vehicle approaches, a switching element connected in series with the power supply coil, and a power supply-side resonant capacitor that resonates with the power supply coil. The power supply unit wirelessly supplies power to the power receiving unit as the automated guided vehicle moves.

2. The power supply system during travel as described in claim 1, The power supply unit includes: A proximity sensor detects that the automated guided vehicle is approaching the power supply coil; and The control circuit, based on the detection output of the proximity sensor, controls the switching element to wirelessly supply power from the power supply unit to the power receiving unit during the movement of the automated guided vehicle.

3. The power supply system in motion as described in claim 2, The power supply unit has multiple power supply coils.

4. The power supply system in motion as described in claim 2, The power receiving unit has multiple power receiving coils.

5. The power supply system in motion as described in claim 2, The DC power supply is a pulsating power supply, which consists of a rectifier stack that rectifies the AC voltage from the AC power supply and a filter capacitor that makes the output voltage pulsate to a certain degree.

6. The power supply system in motion as described in claim 2, The control circuit drives the switching element at a substantially fixed frequency during the period when the automated guided vehicle passes a position close to the power supply coil.

7. The power supply system in motion as described in claim 4, The power receiving unit has multiple AC-DC converters. The plurality of receiving coils are connected to the plurality of ACDC converters. The outputs of the multiple ACDC converters are connected to the energy storage components of the automated guided vehicle.

8. The power supply system in motion as described in claim 3, The plurality of power supply coils are connected to the plurality of high-frequency inverters. The control circuit drives the multiple switching elements of the multiple high-frequency inverters at a substantially fixed frequency during the period when the automated guided vehicle passes a position close to the multiple power supply coils.

9. The power supply system in motion as described in claim 5, The control circuit drives the switching elements of the high-frequency inverter, which is driven by the pulsating power, using a drive signal that is frequency-modulated to suppress the higher harmonics of the AC power supply current.

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