Power transmission and reception systems, power transmission equipment, and power receiving equipment

Abstract

This system improves the efficiency of power transmission and reception systems and controls power by controlling the on-time of semiconductor elements. [Solution] The power transmission and reception system comprises a plurality of coils and a plurality of rectifier circuits, each of which includes a switching element capable of controlling the rectification operation by switching, and controls the combination of coils and rectifier circuits according to the power transmission and reception state.

Description

Technical Field

[0001] The present invention relates to a power transmission and reception system, a power transmission device, and a power reception device.

Background Art

[0002] A power transmission and reception system including a roadside coil and a roadside inverter, and a vehicle-side coil, a rectifier circuit, and a resonance circuit has been disclosed (Patent Document 1). The rectifier circuit has an active semiconductor element and a voltage sensor, and non-contact power transmission and reception are performed on the power by the roadside coil and the roadside inverter. In this power transmission and reception system, the coil is connected to a two-phase leg, and the timing of turning on each switch is detected by a voltage detection circuit of each leg, and a gate signal is generated based on this to realize a synchronous rectification operation. In addition, when the output current is sufficiently low according to the detected value of the output power, unnecessary switching is prevented by prohibiting the switch operation in each leg.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, it is necessary to turn on the high-side switch after the high-side diode conducts. However, in the discontinuous current mode at low power, that is, before sufficient current flows, it is difficult to detect the timing when the diode conducts. Also, since no power is being received, the loss in the diode is small, and the effect of synchronous rectification control is small.

[0005] Therefore, it is desired to improve the efficiency by synchronous rectification control, and it is preferable to improve the safety by controlling the power charged by the current.

Means for Solving the Problems

[0006] One aspect of the present invention is a power transmission and reception system comprising a plurality of coils and a plurality of rectifier circuits, each of which is configured to include a switching element capable of controlling the rectification operation by switching, and characterized in that control is performed to switch the combination of the coils and the rectifier circuits according to the power transmission and reception state.

[0007] In this case, it is preferable to include a sensor for detecting the state of power transmission and reception, and to perform control to switch the combination of the coil and the rectifier circuit according to the output of the sensor.

[0008] Furthermore, it is preferable to have multiple sensors and to perform control that switches the combination of the coil and the rectifier circuit according to the difference in output between the sensors.

[0009] Furthermore, the sensor is provided in each of the plurality of rectifier circuits and is a current sensor that detects the DC current on the DC side, and it is preferable to control the combination of the coil and the rectifier circuit according to the difference in output between the current sensors.

[0010] Furthermore, the sensor is provided in each of the plurality of rectifier circuits and is a current sensor that detects the AC current on the AC side, and it is preferable to control the combination of the coil and the rectifier circuit according to the difference in output between the current sensors.

[0011] Furthermore, the sensor is a voltage sensor provided in each of the plurality of rectifier circuits for detecting the AC voltage, and it is preferable to control the combination of the coil and the rectifier circuit according to the difference in output between the voltage sensors.

[0012] Furthermore, it is preferable that each of the rectifier circuits includes a plurality of legs in which the switching elements are connected in series, and that the plurality of coils include coils connected between the legs included in each of the rectifier circuits and coils connected between the legs included in different rectifier circuits.

[0013] Another aspect of the present invention is a power transmission device comprising a plurality of coils and a plurality of rectifier circuits, each of which is configured to include a switching element capable of controlling the rectification operation by switching, and characterized in that it performs control to switch the combination of the coils and the rectifier circuits according to the power transmission and reception state.

[0014] Another aspect of the present invention is a power receiving device comprising a plurality of coils and a plurality of rectifier circuits, each of which is configured to include a switching element capable of controlling the rectification operation by switching, and characterized in that it performs control to switch the combination of the coils and the rectifier circuits according to the power transmission and reception state. [Effects of the Invention]

[0015] According to the present invention, the efficiency of the power transmission and reception system can be improved, and power can be controlled by controlling the on-time of semiconductor elements. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows the configuration of a power transmission and reception system in an embodiment of the present invention. [Figure 2] This figure shows the configuration of a power transmission and reception system to which control using a DC current sensor is applied according to an embodiment of the present invention. [Figure 3] This figure shows the control flow using a DC current sensor in an embodiment of the present invention. [Figure 4] This figure summarizes the control modes and conditional expressions using a DC current sensor in an embodiment of the present invention. [Figure 5] This figure shows the results of a simulation of control using a DC current sensor in an embodiment of the present invention. [Figure 6] This figure shows the configuration of a power transmission and reception system to which control using an alternating current (AC) sensor is applied according to an embodiment of the present invention. [Figure 7]This figure shows the control flow using an AC current sensor in an embodiment of the present invention. [Figure 8] This figure summarizes the control modes and conditional expressions using an AC current sensor in an embodiment of the present invention. [Figure 9] This figure shows the results of a simulation of control using an AC current sensor in an embodiment of the present invention. [Figure 10] This figure shows the configuration of a power transmission and reception system to which control using a voltage sensor is applied according to an embodiment of the present invention. [Figure 11] This figure shows the control flow using a voltage sensor in an embodiment of the present invention. [Figure 12] This figure summarizes the control modes and conditional expressions using a voltage sensor in an embodiment of the present invention. [Figure 13] This figure shows the results of a simulation of control using a voltage sensor in an embodiment of the present invention. [Figure 14] This figure shows the configuration of another example of a power transmission and reception system in an embodiment of the present invention. [Modes for carrying out the invention]

[0017] The power transmission and reception system 100 in the embodiment of the present invention is configured to include a primary circuit 102 and a secondary circuit 104. The primary circuit 102 is configured to include an AC power supply 10, a primary capacitor 12, and a primary inductor (primary coil) 14. The secondary circuit 104 is configured to include a first synchronous rectifier circuit 20a, a second synchronous rectifier circuit 20b, secondary inductors (secondary coils) 16 (16a, 16b, 16c, 16d), secondary capacitors 18 (18a, 18b, 18c, 18d), smoothing capacitors 22 (22a, 22b), and a storage battery 24.

[0018] The power transmission and reception system 100 is mainly composed of a synchronous rectifier circuit and is used to convert the AC power supply in the primary circuit 102 to DC power for charging and discharging the battery 24 in the secondary circuit 104. Switching elements and recirculation diodes are used in the power transmission and reception system 100 to improve rectification efficiency. In the power transmission and reception system 100, the primary circuit 102 can be the power transmission side and the secondary circuit 104 can be the power reception side. Alternatively, these can be reversed, with the primary circuit 102 being the power reception side and the secondary circuit 104 being the power transmission side.

[0019] The first synchronous rectifier circuit 20a is composed of switching elements (parallel-connected recirculating diodes) 20a-1, 20a-2, 20a-3, and 20a-4. The switching elements 20a-1, 20a-2, 20a-3, and 20a-4 rectify AC power and efficiently convert it to DC. The recirculating diodes are connected in parallel with the switching elements to improve rectification efficiency.

[0020] The second synchronous rectifier circuit 20b is composed of switching elements (parallel-connected recirculating diodes) 20b-1, 20b-2, 20b-3, and 20b-4. The switching elements 20b-1, 20b-2, 20b-3, and 20b-4 rectify AC power and efficiently convert it to DC. The recirculating diodes are connected in parallel with the switching elements to improve rectification efficiency.

[0021] Each of the secondary inductors 16 (16a, 16b, 16c, 16d) is combined with each of the secondary capacitors 18 (18a, 18b, 18c, 18d) to form a resonant circuit. In the following description, the secondary inductors 16 (16a, 16b, 16c, 16d) or their inductances may be represented as L1, L2, L3, and L4, respectively. The secondary inductors 16 (16a, 16b, 16c, 16d) and secondary capacitors 18 (18a, 18b, 18c, 18d) perform the functions of storing and releasing electrical energy.

[0022] The smoothing capacitors 22 (22a, 22b) smooth the DC voltage and reduce ripple. As a result, the battery 24 is charged and discharged with a stable DC output.

[0023] In the primary circuit 102, AC power is supplied to the primary inductor 14 through the primary capacitor 12.

[0024] In the first synchronous rectifier circuit 20a, the drain terminal of switching element 20a-1 is connected to one end of the smoothing capacitor 22a and the positive terminal of the battery 24. The source terminal of switching element 20a-1 is connected to the drain terminal of switching element 20a-2. The source terminal of switching element 20a-2 is connected to the other end of the smoothing capacitor 22a and the negative terminal of the battery 24. Hereinafter, the pair of switching elements 20a-1 and 20a-2 will be referred to as Leg A. The drain terminal of switching element 20a-3 is connected to one end of the smoothing capacitor 22a and the positive terminal of the battery 24. The source terminal of switching element 20a-3 is connected to the drain terminal of switching element 20a-4. The source terminal of switching element 20a-4 is connected to the other end of the smoothing capacitor 22a and the negative terminal of the battery 24. Hereinafter, the pair of switching elements 20a-3 and 20a-4 will be referred to as Leg B.

[0025] Furthermore, one end of the resonant circuit consisting of the secondary inductor 16a and the secondary capacitor 18a is connected to the connection point between the source terminal of switching element 20a-1 and the drain terminal of switching element 20a-2. In addition, one end of the resonant circuit consisting of the secondary inductor 16b and the secondary capacitor 18b is connected to the connection point between the source terminal of switching element 20a-3 and the drain terminal of switching element 20a-4.

[0026] In the second synchronous rectifier circuit 20b, the drain terminal of switching element 20b-1 is connected to one end of the smoothing capacitor 22b and the positive terminal of the battery 24. The source terminal of switching element 20b-1 is connected to the drain terminal of switching element 20b-2. The source terminal of switching element 20b-2 is connected to the other end of the smoothing capacitor 22b and the negative terminal of the battery 24. Hereinafter, the pair of switching elements 20b-1 and 20b-2 will be referred to as Leg C. The drain terminal of switching element 20b-3 is connected to one end of the smoothing capacitor 22b and the positive terminal of the battery 24. The source terminal of switching element 20b-3 is connected to the drain terminal of switching element 20b-4. The source terminal of switching element 20b-4 is connected to the other end of the smoothing capacitor 22b and the negative terminal of the battery 24. Hereinafter, the pair of switching elements 20b-3 and 20b-4 will be referred to as Leg D.

[0027] Furthermore, one end of the resonant circuit consisting of the secondary inductor 16c and the secondary capacitor 18c is connected to the connection point between the source terminal of switching element 20b-1 and the drain terminal of switching element 20b-2. In addition, one end of the resonant circuit consisting of the secondary inductor 16d and the secondary capacitor 18d is connected to the connection point between the source terminal of switching element 20b-3 and the drain terminal of switching element 20b-4.

[0028] The secondary inductor 16a and secondary capacitor 18a, the secondary inductor 16b and secondary capacitor 18b, the secondary inductor 16c and secondary capacitor 18c, and the secondary inductor 16d and secondary capacitor 18d are connected in parallel.

[0029] [Control using a DC current sensor] Figure 2 shows the configuration of the power transmission and reception system 100 to which control using DC current sensors 30a and 30b is applied. The power transmission and reception system 100 has a first synchronous rectifier circuit 20a with current I dc1 The current I measured by the DC sensor 30a and the second synchronous rectifier circuit 20b dc2A DC direct current sensor 30b for measurement is provided. The control unit 106 measures the current I of the first synchronous rectifier circuit 20a dc1 and the current I of the second synchronous rectifier circuit 20b dc2 and performs switching control of the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b according to the currents I dc1 and I dc2 .

[0030] FIG. 3 is a diagram showing a control flow using DC (direct current) current sensors 30a and 30b. FIG. 4 is a diagram summarizing the conditional expressions for each mode in this control.

[0031] The control unit 106 calculates the absolute value of the difference between the current I dc1 and the current I dc2 , |I dc1 -I dc2 |. When all the conditions that this value is greater than a constant β times the maximum current I max , the current I dc1 is greater than the current I dc2 , and the current I dc1 is greater than a constant α times the maximum current I max are satisfied, it is determined that the state is in Mode 1 where the primary inductor 14 of the primary side circuit 102 is most strongly coupled to the secondary inductors 16a and 16b (L1, L2) of the secondary side circuit 104. In this case, the legs A and B are subjected to synchronous switching control, and the legs C and D are turned off, so that rectification is performed using the legs A and B.

[0032] Also, the control unit 106 calculates the absolute value of the difference between the current I dc1 and the current I<00​​​​​​​​​​​​​​If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 2, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16c, 16d (L3, L4) of the secondary circuit 104. In this case, legs A and B are turned off, and legs C and D are controlled by synchronous switching, thereby performing rectification using legs C and D.

[0033] Furthermore, the control unit 106 controls the current I dc1 and current I dc2 The absolute value of the difference between |I| dc1 -I dc2 | is the maximum current I max Smaller than a constant β times, current I dc1 The maximum current I max The current I is greater than a constant α. dc2 The maximum current I max If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 3, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16b, 16c (L2, L3) of the secondary circuit 104. In this case, legs A and D are turned off, and legs B and C are controlled by synchronous switching, thereby performing rectification using legs B and C.

[0034] Furthermore, if none of the above conditions are met, the control unit 106 turns off all of Leg A, Leg B, Leg C, and Leg D and stops charging and discharging.

[0035] Furthermore, it is preferable to set constants α and β to different values. For example, it is preferable to set them such that constant α > constant β. Specifically, for example, constant α is set to 0.10 and constant β is set to 0.05. By setting constants α and β in this way, the chattering phenomenon, in which the leg used frequently switches around the reference value of the above conditions, can be suppressed.

[0036] Figure 5 shows the results of a simulation of the charging and discharging of the battery 24 in a moving vehicle, with the primary circuit 102 positioned as the power transmission side and the secondary circuit 104 mounted on the vehicle as the power reception side. In Figure 5, the horizontal axis represents the time when the vehicle is traveling at 130 km / h.

[0037] During vehicle operation, the mutual inductance changes depending on the relative positions of the primary circuit 102 and the secondary circuit 104. Therefore, power is charged and discharged from the coil with the highest mutual inductance with the primary inductor 14 among the secondary inductors 16 (16a, 16b, 16c, 16d).

[0038] According to the power transmission and reception system 100, with the change in mutual inductance, the current 1(I dc1 ) and current 2(I dc2 The relative magnitudes of the two components switch, and modes 1 to 3 are switched appropriately. In other words, by applying the power transmission and reception system 100, each leg included in the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b is switched appropriately to perform rectification, and the chattering phenomenon is also suppressed during switching.

[0039] [Control using AC current sensor] Figure 6 shows the configuration of the power transmission and reception system 100 to which control using AC current sensors 32a and 32b is applied. The power transmission and reception system 100 has a first synchronous rectifier circuit 20a with current I ac1 The current I measured by the AC / DC sensor 32a and the second synchronous rectifier circuit 20b ac2 A DC sensor 32b is provided to measure the current I of the first synchronous rectifier circuit 20a. ac1 and the current I of the second synchronous rectifier circuit 20b ac2 Upon receiving an input, current I ac1 and current I ac2 The switching control of the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b is performed accordingly.

[0040] Figure 7 shows the control flow using AC current sensors 32a and 32b. Figure 8 summarizes the conditional equations for each mode in this control. In the following explanation, the current value represents the average value of the AC current.

[0041] The control unit 106 controls the current I ac1 and current I ac2 The absolute value of the difference between |I| ac1 -I ac2 | is the maximum current I max The current I is greater than the constant β times. ac1 Current I ac2 Larger, current I ac1 The maximum current I max If all conditions are met, including that the constant is greater than α times, it is determined that the state is Mode 1, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16a, 16b (L1, L2) of the secondary circuit 104. In this case, rectification is performed using legs A and B by synchronous switching control of legs A and B and turning off legs C and D.

[0042] Furthermore, the control unit 106 controls the current I ac1 and current I ac2 The absolute value of the difference between |I| ac1 -I ac2 | is the maximum current I max The current I is greater than the constant β times. ac2 Current I ac1 Larger, current I ac2 The maximum current I max If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 2, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16c, 16d (L3, L4) of the secondary circuit 104. In this case, legs A and B are turned off, and legs C and D are controlled by synchronous switching, thereby performing rectification using legs C and D.

[0043] Furthermore, the control unit 106 controls the current I ac1 and current I ac2 The absolute value of the difference between |I| ac1 -Iac2 | is the maximum current I max Smaller than a constant β times, current I ac1 The maximum current I max The current I is greater than a constant α. ac2 The maximum current I max If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 3, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16b, 16c (L2, L3) of the secondary circuit 104. In this case, legs A and D are turned off, and legs B and C are controlled by synchronous switching, thereby performing rectification using legs B and C.

[0044] Furthermore, if none of the above conditions are met, the control unit 106 turns off all of Leg A, Leg B, Leg C, and Leg D and stops charging and discharging.

[0045] In this case as well, it is preferable to set constants α and β to different values. For example, it is preferable to set them such that constant α > constant β. Specifically, for example, constant α is set to 0.10 and constant β is set to 0.05. By setting constants α and β in this way, it is possible to suppress the chattering phenomenon in which the legs used frequently switch around the reference value of the above conditions.

[0046] Figure 9 shows the results of a simulation of the charging and discharging of the battery 24 in a moving vehicle, with the primary circuit 102 positioned as the power transmission side and the secondary circuit 104 mounted on the vehicle as the power reception side. In Figure 9, the horizontal axis represents the time when the vehicle is traveling at 130 km / h.

[0047] During vehicle operation, the mutual inductance changes according to the relative positions of the primary circuit 102 and the secondary circuit 104, and consequently the current 1(I ac1 ) and current 2(I ac2 The relative magnitudes of the currents switch, and modes 1 to 3 are switched appropriately. In mode 1, the current is 1 (I ac1 Only ) was detected, and current 2(I ac2 ) is current 1(Iac1 It is significantly smaller compared to ). In mode 2, the current is 1 (I ac2 Only ) was detected, and current 1 (I ac1 ) is current 1(I ac2 It is sufficiently small compared to ). In mode 3, the current is 1 (I ac1 ) and current 1(I ac2 ) are of similar magnitude.

[0048] By applying the power transmission and reception system 100, each leg included in the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b is appropriately switched to perform rectification, and chattering during switching is also suppressed.

[0049] [Control via voltage sensor] Figure 10 shows the configuration of a power transmission and reception system 100 to which control using voltage sensors 34a and 34b is applied. The power transmission and reception system 100 is equipped with a voltage sensor 34a that measures the voltage V12 of the first synchronous rectifier circuit 20a and a voltage sensor 34b that measures the voltage V34 of the second synchronous rectifier circuit 20b. The control unit 106 receives inputs of the voltage V12 of the first synchronous rectifier circuit 20a and the voltage V34 of the second synchronous rectifier circuit 20b, and performs switching control of the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b according to the voltages V12 and V34.

[0050] Figure 11 shows the control flow using voltage sensors 34a and 34b. Figure 12 is a diagram summarizing the conditional equations for each mode in this control. In the following explanation, the voltage and current values ​​will be assumed to be average values ​​of AC.

[0051] The control unit 106 determines that the absolute value of the difference between voltage V12 and voltage V34 |V12-V34| is the maximum current I max The constant β is greater than the maximum current I, the voltage V12 is greater than the voltage V34, and the voltage V12 is greater than the maximum current I maxIf all conditions are met, including that the constant is greater than α times, it is determined that the state is Mode 1, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16a, 16b (L1, L2) of the secondary circuit 104. In this case, rectification is performed using legs A and B by synchronous switching control of legs A and B and turning off legs C and D.

[0052] Furthermore, the control unit 106 determines that the absolute value of the difference between voltage V12 and voltage V34 |V12-V34| is the maximum current I max The constant β is greater than the maximum current I, the voltage V34 is greater than the voltage V12, and the voltage V34 is greater than the maximum current I max If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 2, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16c, 16d (L3, L4) of the secondary circuit 104. In this case, legs A and B are turned off, and legs C and D are controlled by synchronous switching, thereby performing rectification using legs C and D.

[0053] Furthermore, the control unit 106 determines that the absolute value of the difference between voltage V12 and voltage V34 |V12-V34| is the maximum current I max The voltage V12 is smaller than the constant β times the maximum current I max The voltage V34 is greater than the constant α times and the maximum current I max If all conditions are met, including that the constant is greater than α times, then it is determined that the state is Mode 3, in which the primary inductor 14 of the primary circuit 102 is most strongly coupled with the secondary inductors 16b, 16c (L2, L3) of the secondary circuit 104. In this case, legs A and D are turned off, and legs B and C are controlled by synchronous switching, thereby performing rectification using legs B and C.

[0054] Furthermore, if none of the above conditions are met, the control unit 106 turns off all of Leg A, Leg B, Leg C, and Leg D and stops charging and discharging.

[0055] In this case as well, it is preferable to set constants α and β to different values. For example, it is preferable to set them such that constant α > constant β. Specifically, for example, constant α is set to 0.10 and constant β is set to 0.05. By setting constants α and β in this way, it is possible to suppress the chattering phenomenon in which the legs used frequently switch around the reference value of the above conditions.

[0056] Figure 13 shows the results of a simulation of the charging and discharging of the battery 24 in a moving vehicle, with the primary circuit 102 positioned as the power transmission side and the secondary circuit 104 mounted on the vehicle as the power reception side. In Figure 13, the horizontal axis represents the time when the vehicle is traveling at 130 km / h.

[0057] While the vehicle is in motion, the mutual inductance changes according to the relative positions of the primary circuit 102 and the secondary circuit 104, and the relative magnitudes of current 1 (V12) and current 2 (V34) switch accordingly, allowing for appropriate switching between modes 1 to 3. In mode 1, voltage V12 is greater than voltage V34; in mode 2, voltage V34 is greater than voltage V12; and in mode 3, voltages V12 and V34 are approximately the same.

[0058] By applying the power transmission and reception system 100, each leg included in the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b is appropriately switched to perform rectification, and chattering during switching is also suppressed.

[0059] [Differentiation] This embodiment includes a plurality of coils and a plurality of rectifier circuits, each of which is configured to include a switching element capable of controlling the rectification operation by switching, and the configuration is such that the combination of coils and rectifier circuits is switched according to the power transmission and reception state.

[0060] As an alternative, as shown in Figure 14, the power transmission and reception system 200 may be configured without secondary inductors 16b, 16d and secondary capacitors 18b, 18d.

[0061] In the power transmission and reception system 200, control using a direct current (DC) sensor, an alternating current (AC) sensor, or a voltage sensor can be applied. In any case, as with the power transmission and reception system 100, current sensors and voltage sensors are provided and control is performed according to the output of the sensors.

[0062] In the case of the power transmission and reception system 200, each leg is switched by applying only the conditions of Mode 1 and Mode 2 described above. That is, when the conditions of Mode 1 are met, Leg A and Leg B are controlled by synchronous switching control, and Leg C and Leg D are turned off, thereby performing rectification using Leg A and Leg B. When the conditions of Mode 2 are met, Leg C and Leg D are controlled by synchronous switching control, and Leg A and Leg B are turned off, thereby performing rectification using Leg C and Leg D. In all other cases, Legs A, B, C, and D are all turned off, and charging and discharging are stopped.

[0063] In the power transmission and reception system 200, each leg included in the first synchronous rectifier circuit 20a and the second synchronous rectifier circuit 20b is appropriately switched to perform rectification, and chattering is suppressed during switching.

[0064] In addition, the number of leg sets may be further increased in the above embodiments and modified examples. In this case as well, the legs can be selected and rectification control performed based on the relative magnitudes of the current or voltage flowing through each synchronous rectifier circuit.

[0065] As described above, the power transmission and reception system in the above embodiment and its modified form has lower diode losses compared to diode rectification, thus improving efficiency. Furthermore, synchronous rectification control can always be performed even when the receiving coil switches, under conditions where the positional relationship between the coils of the primary and secondary circuits changes. Therefore, when the power transmission and reception system is applied to a vehicle or the like, the overall efficiency during operation can be improved.

[0066] Furthermore, power can be controlled by controlling the on-time of active semiconductor elements. Therefore, it is possible to prevent the battery from being overcharged or when charging is not needed, thereby improving safety.

[0067] [Structure of the present invention] [Configuration 1] It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power transmission and reception system characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status. [Configuration 2] The power transmission and reception system described in Configuration 1, A power transmission and reception system characterized by comprising a sensor for detecting the state of power transmission and reception, and performing control to switch the combination of the coil and the rectifier circuit according to the output of the sensor. [Configuration 3] The power transmission and reception system described in Configuration 2, A power transmission and reception system characterized by comprising a plurality of the aforementioned sensors and performing control to switch the combination of the coil and the rectifier circuit according to the difference in output between the sensors. [Structure 4] The power transmission and reception system described in configuration 3, The power transmission and reception system is characterized in that the sensor is a current sensor provided in each of the plurality of rectifier circuits for detecting the DC current on the DC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the current sensors. [Composition 5] The power transmission and reception system described in configuration 3, The power transmission and reception system is characterized in that the sensor is a current sensor provided in each of the plurality of rectifier circuits for detecting the AC current on the AC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the current sensors. [Composition 6] The power transmission and reception system described in configuration 3, The power transmission and reception system is characterized in that the sensor is a voltage sensor provided in each of the plurality of rectifier circuits for detecting the voltage on the AC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the voltage sensors. [Composition 7] A power transmission and reception system as described in any one of items 1 to 6, Each of the rectifier circuits includes a plurality of legs in which the switching elements are connected in series. The plurality of coils include coils connected between legs included in each of the rectifier circuits and coils connected between legs included in different rectifier circuits. A power transmission and reception system characterized by the following features. [Structure 8] It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power transmission device characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status. [Composition 9] It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power receiving device characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status. [Explanation of symbols]

[0068] 10 AC power supply, 12 primary capacitor, 14 primary inductor (primary coil), 16 (16a, 16b, 16c, 16d) secondary inductor (secondary coil), 18 (18a, 18b, 18c, 18d) secondary capacitor, 20a first synchronous rectifier circuit, 20b second synchronous rectifier circuit, 20a-1, 20a-2, 20a-3, 20a-4, 20b-1, 20b-2, 20b-3, 20b-4 switching element (parallel connection of circulating diodes), 22 (22a, 22b) smoothing capacitor, 24 storage battery, 30a, 30b DC current sensor, 32a, 32b AC current sensor, 34a, 34b voltage sensor, 100, 200 power transmission and reception system, 102 primary circuit, 104 secondary circuit, 106 Control unit.

Claims

1. It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power transmission and reception system characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status.

2. A power transmission and reception system according to claim 1, A power transmission and reception system characterized by comprising a sensor for detecting the state of power transmission and reception, and performing control to switch the combination of the coil and the rectifier circuit according to the output of the sensor.

3. A power transmission and reception system according to claim 2, A power transmission and reception system characterized by comprising a plurality of the aforementioned sensors and performing control to switch the combination of the coil and the rectifier circuit according to the difference in output between the sensors.

4. A power transmission and reception system according to claim 3, The power transmission and reception system is characterized in that the sensor is a current sensor provided in each of the plurality of rectifier circuits for detecting the DC current on the DC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the current sensors.

5. A power transmission and reception system according to claim 3, The power transmission and reception system is characterized in that the sensor is a current sensor provided in each of the plurality of rectifier circuits for detecting the AC current on the AC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the current sensors.

6. A power transmission and reception system according to claim 3, The power transmission and reception system is characterized in that the sensor is a voltage sensor provided in each of the plurality of rectifier circuits for detecting the voltage on the AC side, and controls the combination of the coil and the rectifier circuit according to the difference in output between the voltage sensors.

7. A power transmission and reception system according to any one of claims 1 to 6, Each of the rectifier circuits includes a plurality of legs in which the switching elements are connected in series. The plurality of coils include coils connected between legs included in each of the rectifier circuits and coils connected between legs included in different rectifier circuits. A power transmission and reception system characterized by the following features.

8. It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power transmission device characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status.

9. It comprises multiple coils and multiple rectifier circuits, Each of the rectifier circuits is configured to include a switching element capable of controlling the rectification operation by switching, A power receiving device characterized by performing control to switch the combination of the coil and the rectifier circuit according to the power transmission and reception status.

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