Charging System

Abstract

The charging system includes an AC power source, a plurality of open / close rectifiers composed of a plurality of rectifier circuits and a plurality of open / close circuits, and a control device. The plurality of rectifier circuits are respectively connected to a plurality of modules formed by dividing a storage battery into a plurality of parts. The plurality of rectifier circuits supply the plurality of modules with DC power obtained by rectifying the AC power supplied from the AC power source. The plurality of open / close circuits switch the connection and disconnection between the AC power source and each of the plurality of modules. The control device controls the connection and disconnection of the plurality of open / close circuits according to a state quantity of at least one of the output voltage of the AC power source and the input voltage of the rectifier circuit or a state quantity associated with at least one of the output voltage and the input voltage.

Description

Technical Field

[0001] The present invention relates to a charging system. Background Art

[0002] Conventionally, for example, there is known a power supply device that supplies power to a power storage device having a plurality of battery cells connected in series (for example, see Japanese Patent Application Laid-Open No. 2011-67021). The power supply device includes: a rectifier circuit that is connected to each of the plurality of modules constituting the power storage device; an AC circuit that sequentially connects the rectifier circuits; and an AC generating circuit that applies an AC voltage to the AC circuit. Summary of the invention

[0003] In the power supply device of the above-mentioned prior art, when the range of the output voltage of the power source provided by the AC generating circuit is restricted, the power conversion circuit such as a DC-DC converter is used to perform voltage conversion, so that the efficiency of power supply may be reduced. For example, if the output voltage of the power source such as a solar cell whose output voltage is restricted due to the reduction of sunlight is stepped down by the DC-DC converter in order to ensure that the power generated at the optimal operating point of the maximum output is charged, the charging power may be reduced due to the reduction of conversion efficiency.

[0004] The present invention has been made in consideration of such a situation, and an object of the present invention is to provide a charging system capable of suppressing a decrease in charging efficiency.

[0005] In order to solve the above problems and achieve the relevant objects, the present invention adopts the following means.

[0006] (1) A charging system according to one embodiment of the present invention charges a storage device formed by connecting a plurality of storage elements, wherein the charging system comprises: an AC power source; a plurality of rectifiers, which are respectively connected to a plurality of modules formed by dividing the storage device into a plurality of modules, and supply DC power obtained by rectifying the AC power supplied from the AC power source to the plurality of modules; a plurality of switch units, which switch the connection and disconnection between the AC power source and each of the plurality of modules; and a control device, which controls the connection and disconnection of the plurality of switch units based on a state quantity of at least one of an output voltage of the AC power source and an input voltage of the rectifier unit, or a state quantity associated with at least one of the output voltage and the input voltage.

[0007] (2) In the above scheme (1), the control device may set an upper limit number of the plurality of opening and closing parts that are simultaneously in a connected state according to the state quantity, and sequentially switch from the plurality of opening and closing parts to select the upper limit number of the opening and closing parts that are in a connected state.

[0008] (3) In the above configuration (2), the control device may control the time of the connection state of each of the plurality of switch units so that the charging states of the plurality of modules are the same.

[0009] According to the above scheme (1), the charging of multiple modules is controlled based on the state quantity of at least one of the output voltage of the AC power source and the input voltage of the rectifier, or the state quantity associated with at least one of the output voltage and the input voltage, so that even if the output voltage of the AC power source is restricted, the reduction in charging efficiency can be suppressed. For example, even if the output voltage of the AC power source is restricted and the output voltage cannot be lowered below the specified voltage, the total amount of charging power supplied to multiple modules can be suppressed. The total amount of charging power supplied to multiple modules can be suppressed without lowering the output voltage of the AC power source, so that the power conversion for stepping up or down the output voltage of the AC power source can be avoided from operating in an area with reduced efficiency, and the conversion loss can be suppressed.

[0010] In the case of the above solution (2), charging of the plurality of modules of the power storage device is partially stopped and the modules whose charging is stopped are sequentially switched, thereby suppressing a decrease in charging efficiency while charging the plurality of modules equally and maintaining a uniform charging state among the modules.

[0011] In the case of the above-mentioned solution (3), even if a difference in the state of charge occurs among a plurality of modules, the difference in the state of charge can be easily corrected by controlling the time of the connection state by utilizing the connection time or connection frequency of each switch unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing the configuration of a charging system in an embodiment of the present invention.

[0013] Figure 2 It is a diagram showing the configuration of an AC power source of a charging system in the embodiment of the present invention.

[0014] Figure 3 It is a diagram showing the configuration of a rectifier circuit and a switching circuit of a charging system in an embodiment of the present invention.

[0015] Figure 4 This is a diagram showing an example of the correspondence relationship between the output voltage of the AC power source, the charging power of the battery, and the number of modules corresponding to the switching rectifiers in the connected state in the charging system according to the embodiment of the present invention.

[0016] Figure 5This is a diagram showing a first example of the on / off pattern of the switch circuits corresponding to the first to fourth blocks in the charging system according to the embodiment of the present invention.

[0017] Figure 6 This is a diagram showing a second example of the on and off patterns of the opening and closing circuits corresponding to the first to fourth blocks in the charging system according to the embodiment of the present invention.

[0018] Figure 7 It is a diagram showing a third example of the on and off patterns of the opening and closing circuits corresponding to the first to fourth blocks in the charging system according to the embodiment of the present invention.

[0019] Figure 8 This is a diagram showing an example of the correspondence relationship between the voltage and current of the DC power supply and the amount of power generation in the charging system according to the embodiment of the present invention.

[0020] Fig. 9 1 is a diagram showing an example of the correspondence relationship between the voltage and power of the DC power source and the amount of generated power in the charging system according to the embodiment of the present invention.

[0021] Fig.10 It is a diagram showing the configuration of a charging system in a first modified example of the embodiment of the present invention.

[0022] Fig.11 It is a diagram showing a configuration of a charging system in a second modified example of the embodiment of the present invention.

[0023] Fig.12 It is a diagram showing the configuration of a rectifier circuit and a switching circuit of a charging system in a third modified example of the embodiment of the present invention.

[0024] Fig.13 It is a diagram showing the configuration of a rectifier circuit and a switching circuit of a charging system in a fourth modified example of the embodiment of the present invention.

[0025] Fig.14 It is a diagram showing the configuration of a rectifier circuit and a switching circuit of a charging system in a fifth modified example of the embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, a charging system 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 Side description.

[0027] Figure 1 It is a diagram showing the configuration of charging system 10 in the embodiment.

[0028] The charging system 10 of this embodiment is mounted on a vehicle such as an electric vehicle. The charging system 10 is connected to a power storage device mounted on the vehicle. Electric vehicles are electric vehicles, hybrid vehicles, fuel cell vehicles, etc. Electric vehicles are driven by batteries as a power source. Hybrid vehicles are driven by batteries and internal combustion engines as power sources. Fuel cell vehicles are driven by fuel cells as a power source.

[0029] like Figure 1 As shown, the power storage device connected to the charging system 10 is, for example, a high-voltage battery 1 as a power source of a vehicle. The battery 1 includes a string 3 formed by a plurality of cells 2 connected in series, and a positive terminal and a negative terminal at both ends of the string 3. The battery 1 includes a plurality of modules 4 formed by dividing the string 3 into a plurality of substrings connected in series. The plurality of modules 4 are, for example, a first module 4a, a second module 4b, a third module 4c, and a fourth module 4d formed by dividing the string 3 into four parts.

[0030] The charging system 10 includes an AC power source 11 , an AC circuit 12 , a plurality of switching rectifying units 14 , and a control device 15 .

[0031] Figure 2 1 is a diagram showing a configuration of an AC power source 11 of a charging system 10 according to the embodiment. Figure 3 1 is a diagram showing the configuration of the switching circuit 41 and the rectifying circuit 42 of the charging system 10 in the embodiment.

[0032] like Figure 2 As shown, the AC power source 11 includes a DC power source 21 , a first power conversion unit 22 , and a second power conversion unit 23 .

[0033] The DC power source 21 is, for example, a solar cell or the like.

[0034] The first power conversion unit 22 includes, for example, a DC-DC converter that performs both step-up and step-down power conversions, etc. The first power conversion unit 22 includes a first positive terminal P1 and a first negative terminal N1 , a second positive terminal P2 and a second negative terminal N2 .

[0035] The first positive terminal P1 and the first negative terminal N1 of the first power converter 22 are connected to the positive terminal DP and the negative terminal DN of the DC power supply 21. The second positive terminal P2 and the second negative terminal N2 of the first power converter 22 are connected to the positive terminal PT and the negative terminal NT of the second power converter 23.

[0036] The first power conversion unit 22, for example, includes a reactor, and switching elements and rectifying elements of a low-side arm and a high-side arm in pairs in two phases. The switching element is a transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semi-conductor Field Effect Transistor). The rectifying element is a diode connected in parallel with each transistor. The reactor is a choke coil L. The first power conversion unit 22 includes a high-side arm first-phase transistor S1H and a low-side arm first-phase transistor S1L in a first phase, and a high-side arm second-phase transistor S2H and a low-side arm second-phase transistor S2L in a second phase. The first power conversion unit 22 includes a freewheeling diode connected in a forward direction from the emitter to the collector between the collector and emitter of each transistor S1H, S1L, S2H, and S2L.

[0037] The collector of the high-side arm first-phase transistor S1H is connected to the first positive terminal P1. The collector of the high-side arm second-phase transistor S2H is connected to the second positive terminal P2. The emitters of the low-side arm first-phase transistor S1L and the low-side arm second-phase transistor S2L are connected to the first negative terminal N1 and the second negative terminal N2. The emitter of the high-side arm first-phase transistor S1H and the collector of the low-side arm first-phase transistor S1L are connected to the first ends of the two ends of the choke coil L. The emitter of the high-side arm second-phase transistor S2H and the collector of the low-side arm second-phase transistor S2L are connected to the second ends of the two ends of the choke coil L.

[0038] The first power conversion unit 22 includes a first smoothing capacitor C1 connected between a first positive terminal P1 and a first negative terminal N1, and a second smoothing capacitor C2 connected between a second positive terminal P2 and a second negative terminal N2. The first smoothing capacitor C1 and the second smoothing capacitor C2 smooth the voltage fluctuations caused by the switching operation of turning on / off of each transistor S1H, S1L, S2H, and S2L.

[0039] The first power conversion unit 22 switches the transistors S1H, S1L, S2H, and S2L between on (conduction) and off (disconnection) based on a gate signal which is a switching command input to the gate of each transistor S1H, S1L, S2H, and S2L.

[0040] The first power conversion unit 22, when boosting, boosts the power input from the DC power supply 21 to the first positive terminal P1 and the first negative terminal N1, and outputs the boosted power from the second positive terminal P2 and the second negative terminal N2. The first power conversion unit 22, when boosting, keeps the high-side arm first-phase transistor S1H turned on (conducting) and the low-side arm first-phase transistor S1L turned off (disconnected).

[0041] The first power conversion unit 22 accumulates magnetic energy by direct current excitation of the reactor (choke coil L) when the high-side arm second-phase transistor S2H is turned off (cut off) and the low-side arm second-phase transistor S2L is turned on (conducted). The first power conversion unit 22 generates a voltage higher than the first positive terminal P1 and the first negative terminal N1 at the second positive terminal P2 and the second negative terminal N2 by superimposing an induced voltage generated by the magnetic energy of the reactor (choke coil L) and a voltage applied to the first positive terminal P1 and the first negative terminal N1 when the high-side arm second-phase transistor S2H is turned on (conducted) and the low-side arm second-phase transistor S2L is turned off (cut off).

[0042] The first power conversion unit 22 steps down the power input from the first positive terminal P1 and the first negative terminal N1 during voltage reduction, and outputs the stepped-down power from the second positive terminal P2 and the second negative terminal N2. The first power conversion unit 22 maintains the high-side arm second-phase transistor S2H turned on (conducting) and the low-side arm second-phase transistor S2L turned off (disconnecting) during voltage reduction.

[0043] The first power conversion unit 22 accumulates magnetic energy by direct current excitation of the reactor (choke coil L) when the high-side arm first-phase transistor S1H is turned on (conducted) and the low-side arm first-phase transistor S1L is turned off (disconnected). The first power conversion unit 22 generates a voltage lower than the first positive terminal P1 and the first negative terminal N1 at the second positive terminal P2 and the second negative terminal N2 by stepping down the induced voltage generated by the magnetic energy of the reactor (choke coil L) when the high-side arm first-phase transistor S1H is turned off (disconnected) and the low-side arm first-phase transistor S1L is turned on (conducted).

[0044] The second power conversion unit 23 includes, for example, an inverter that converts the DC power input from the first power conversion unit 22 into AC power and outputs the AC power to the AC circuit 12 .

[0045] The second power conversion unit 23 includes, for example, a bridge circuit formed of a plurality of switching elements and rectifying elements connected in a bridge in two phases, A and B. The switching elements are transistors such as IGBTs and MOSFETs. The rectifying elements are diodes connected in parallel to the transistors.

[0046] The second power conversion unit 23 includes a high-side arm A-phase transistor SaH and a low-side arm A-phase transistor SaL that form a pair in the A phase, and a high-side arm B-phase transistor SbH and a low-side arm B-phase transistor SbL that form a pair in the B phase. The second power conversion unit 23 includes a freewheeling diode connected in a forward direction from the emitter to the collector between the collector and the emitter of each of the transistors SaH, SaL, SbH, and SbL.

[0047] The collectors of the high-side arm A-phase transistor SaH and the high-side arm B-phase transistor SbH are connected to the positive terminal PT. The emitters of the low-side arm A-phase transistor SaL and the low-side arm B-phase transistor SbL are connected to the negative terminal NT. The emitter of the high-side arm A-phase transistor SaH and the collector of the low-side arm A-phase transistor SaL are connected to the A-phase terminal AT. The emitter of the high-side arm B-phase transistor SbH and the collector of the low-side arm B-phase transistor SbL are connected to the B-phase terminal BT.

[0048] The second power conversion unit 23 switches the transistor pairs of each phase on (conduction) / off (cut-off) based on the switching instructions, i.e., gate signals, input to the gates of the transistors SaH, SaL, SbH, and SbL. The second power conversion unit 23 converts the DC power input from the positive terminal PT and the negative terminal NT into single-phase AC power and outputs it from the A-phase terminal AT and the B-phase terminal BT. The A-phase terminal AT of the second power conversion unit 23 is connected to the A-phase terminal 12a of the AC circuit 12, and the B-phase terminal BT of the second power conversion unit 23 is connected to the B-phase terminal 12b of the AC circuit 12.

[0049] The AC power source 11 supplies the same current (power) to each module 4 of the battery 1 while generating AC with a frequency close to the resonance frequency of a circuit of LC strings 34 and inductors 33 of the AC circuit 12 described later, for example.

[0050] like Figure 1 As shown, the AC circuit 12 connects the AC power source 11 to the plurality of switching rectifiers 14. The AC circuit 12 includes, for example, an A-phase circuit 31 and a B-phase circuit 32, and a plurality of inductors 33 connected between the A-phase circuit 31 and the B-phase circuit 32 and the plurality of switching rectifiers 14, respectively.

[0051] The A-phase circuit 31 and the B-phase circuit 32 each include a plurality of LC columns 34 connected in series. Each LC column 34 includes a capacitor and an inductor connected in series. The number of the plurality of LC columns 34 in each of the A-phase circuit 31 and the B-phase circuit 32 is the same as the number of the plurality of switching rectifiers 14 (i.e., the plurality of modules 4). For example, the plurality of LC columns 34 are four LC columns 34, the same number as the four switching rectifiers 14. The four LC columns 34 are a first LC column 34a, a second LC column 34b, a third LC column 34c, and a fourth LC column 34d connected in series in sequence. The combination of the capacitance of the capacitors and the inductance of the inductors of the plurality of LC columns 34 may also be a combination that is different from one another among the plurality of LC columns 34.

[0052] The number of the plurality of inductors 33 is the number of inductors 33 corresponding to each of the plurality of switching rectifiers 14 (i.e., the plurality of modules 4) described later. For example, the plurality of inductors 33 is eight inductors 33 corresponding to each of the four switching rectifiers 14. As described later, the four switching rectifiers 14 are the first switching rectifier 14a, the second switching rectifier 14b, the third switching rectifier 14c, and the fourth switching rectifier 14d. The value of the inductance of each of the plurality of inductors 33 may be different from each other among the plurality of inductors 33.

[0053] The first end 31a of the two ends of the A-phase circuit 31 is connected to the A-phase terminal AS of the first opening and closing rectifier 14a via an inductor 33. The first end 32a of the two ends of the B-phase circuit 32 is connected to the B-phase terminal BS of the first opening and closing rectifier 14a via an inductor 33. The connection point 31b between the first LC column 34a and the second LC column 34b of the A-phase circuit 31 is connected to the A-phase terminal AS of the second opening and closing rectifier 14b via an inductor 33. The connection point 32b between the first LC column 34a and the second LC column 34b of the B-phase circuit 32 is connected to the B-phase terminal BS of the second opening and closing rectifier 14b via an inductor 33.

[0054] The connection point between the second LC column 34b and the third LC column 34c of the A phase circuit 31 is the A phase terminal 12a of the AC circuit 12. The connection point between the second LC column 34b and the third LC column 34c of the B phase circuit 32 is the B phase terminal 12b of the AC circuit 12.

[0055] A connection point 31c between the third LC column 34c and the fourth LC column 34d of the A-phase circuit 31 is connected to the A-phase terminal AS of the third switching rectifier 14c via an inductor 33. A connection point 32c between the third LC column 34c and the fourth LC column 34d of the B-phase circuit 32 is connected to the B-phase terminal BS of the third switching rectifier 14c via an inductor 33.

[0056] The second end 31d of the A-phase circuit 31 is connected to the A-phase terminal AS of the fourth opening and closing rectifier 14d via an inductor 33. The second end 32d of the B-phase circuit 32 is connected to the B-phase terminal BS of the fourth opening and closing rectifier 14d via an inductor 33.

[0057] For example, when the product of the combined capacitance and the combined inductance of the LC columns 34 and the inductors 33 is set to be the same for each module 4 of the battery 1 , the AC circuit 12 has the same resonance frequency for each module 4 and supplies the same current (power).

[0058] The plurality of opening and closing rectifying parts 14 are the first opening and closing rectifying part 14a, the second opening and closing rectifying part 14b, the third opening and closing rectifying part 14c and the fourth opening and closing rectifying part 14d which are sequentially connected to the first module 4a, the second module 4b, the third module 4c and the fourth module 4d.

[0059] like Figure 3 As shown, each of the plurality of opening and closing rectifying units 14 includes two opening and closing circuits 41 and a rectifying circuit 42 .

[0060] The two opening and closing circuits 41 are connected between the A-phase terminal AS and the B-phase terminal BS of the opening and closing rectifier 14 and the rectifier circuit 42. The two opening and closing circuits 41 each include, for example, a switch formed by a switching element and a rectifier element. The switching element is a transistor such as an IGBT or a MOSFET. The rectifier element is a diode connected in parallel with each transistor. The opening and closing circuit 41 is, for example, a bidirectional switch including two sets of switching elements and rectifier elements.

[0061] The switching circuit 41 includes a first transistor 41 a and a second transistor 41 b connected in anti-series, and a flyback diode connected in a forward direction from the emitter to the collector between the collector and the emitter of each of the transistors 41 a and 41 b.

[0062] The emitters of the first transistor 41 a and the second transistor 41 b are connected to each other. The collector of the first transistor 41 a is connected to the A-phase terminal AS (or the B-phase terminal BS). The collector of the second transistor 41 b is connected to the first AC terminal 42A (or the second AC terminal 42B) of the rectifier circuit 42 .

[0063] The switch circuit 41 switches the connection (conduction) / disconnection (disconnection) of the first transistor 41a and the second transistor 41b based on the same switch command, i.e., the gate signal, input to the gates of the first transistor 41a and the second transistor 41b. The switch circuit 41 switches the connection and disconnection between the AC circuit 12 and the rectifier circuit 42 by turning on (conduction) / disconnection (disconnection) of the first transistor 41a and the second transistor 41b.

[0064] The rectifier circuit 42 is connected between the two opening and closing circuits 41 and the positive terminal PR and the negative terminal NR of the opening and closing rectifier 14. The rectifier circuit 42 includes, for example, a bridge circuit formed of a plurality of diodes connected in a bridge in two columns, the first column and the second column.

[0065] The rectifier circuit 42 is, for example, a full-wave rectifier circuit and includes a first diode 42a and a second diode 42b connected in the first column in the forward direction, and a third diode 42c and a fourth diode 42d connected in the second column in the forward direction.

[0066] The anode of the first diode 42a and the cathode of the second diode 42b are connected to the first AC terminal 42A. The anode of the third diode 42c and the cathode of the fourth diode 42d are connected to the second AC terminal 42B.

[0067] The cathodes of the first diode 42a and the third diode 42c are connected to the positive terminal PR. The anodes of the second diode 42b and the fourth diode 42d are connected to the negative terminal NR. The positive terminal PR and the negative terminal NR of the rectifier circuit 42 are connected to the positive terminal and the negative terminal of the corresponding module 4 in the battery 1.

[0068] The rectifier circuit 42 performs full-wave rectification on the AC power input from the first AC terminal 42A and the second AC terminal 42B, and outputs the rectified DC power from the positive terminal PR and the negative terminal NR.

[0069] like Figure 1 As shown, the control device 15 controls the operation of the charging system 10. For example, the control device 15 is a software function unit that performs functions by executing a predetermined program by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit) having electronic circuits such as a processor such as a CPU, a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, and a timer. At least a part of the control device 15 may also be an integrated circuit such as an LSI (Large Scale Integration).

[0070] The control device 15 sets the timing for driving the switching elements of the AC power source 11 and the plurality of switching rectifiers 14 to turn on / off, and generates a gate signal for actually driving the switching elements to turn on / off.

[0071] The control device 15 controls connection and disconnection of the plurality of switching rectifiers 14 based on a state quantity of at least one of the output voltage of the AC power source 11 and the input voltage of the switching rectifier 14 or a state quantity related to at least one of the output voltage and the input voltage.

[0072] Figure 4 The diagram shows an example of the correspondence relationship among the output voltage of the AC power source 11 , the charging power of the battery 1 , and the number of modules 4 corresponding to the switching rectifiers 14 in the connected state in the charging system 10 according to the embodiment. Figure 5 The diagram is a diagram showing a first example of the on / off pattern of the switch circuits 41 corresponding to the first to fourth modules 4 a , 4 b , 4 c , and 4 d in the charging system 10 according to the embodiment. Figure 6 The diagram shows a second example of the on / off pattern of the switch circuits 41 corresponding to the first to fourth modules 4 a , 4 b , 4 c , and 4 d in the charging system 10 according to the embodiment. Figure 7 The diagram is a diagram showing a third example of the on and off patterns of the switch circuits 41 corresponding to the first to fourth modules 4 a , 4 b , 4 c , and 4 d in the charging system 10 according to the embodiment.

[0073] The control device 15 sets the upper limit number of modules 4 that are charged simultaneously, that is, the upper limit number of switching rectifiers 14 that are connected simultaneously, among the plurality of modules 4, for example, based on the output voltage of the AC power source 11. The control device 15 sequentially switches from the plurality of switching rectifiers 14 and selects the upper limit number of switching rectifiers 14 that are connected simultaneously.

[0074] For example, Figure 4 As shown, as the output voltage Vac of the AC power source 11 increases, the charging power PM for the storage battery 1 changes to an increasing trend. As the number of modules 4 that are charged simultaneously (the number of connected modules) increases among the plurality of modules 4, the charging power PM for the storage battery 1 changes to an increasing trend. For example, when the output voltage Vac of the AC power source 11 decreases, the control device 15 can reduce the charging power for the storage battery 1 by reducing the number of modules 4 that are charged simultaneously (the number of connected modules).

[0075] For example, in Module 4, Figure 5 In the first embodiment shown, the upper limit is 3. Figure 6 In the second embodiment shown, the upper limit number is 2. Figure 7In the third embodiment shown, the upper limit number is 1. In each of the first embodiment, the second embodiment and the third embodiment, the upper limit number of modules 4 that become connected in each time interval after time t0 (for example, the interval from time t0 to time t1, the interval from time t1 to time t2, the interval from time t2 to time t3, the interval from time t3 to time t4, etc.) are sequentially switched from the plurality of modules 4.

[0076] As described above, the charging system 10 of the embodiment controls the charging of the plurality of modules 4 based on the state quantity of at least one of the output voltage of the AC power source 11 and the input voltage of the rectifier circuit 42 or the state quantity associated with at least one of the output voltage and the input voltage. Thus, even when the output voltage of the AC power source 11 is restricted, the reduction in charging efficiency can be suppressed. For example, even when the output voltage of the AC power source 11 is restricted and the output voltage cannot be lowered below a prescribed voltage, the total amount of charging power supplied to the plurality of modules 4 can be suppressed. Since the total amount of charging power supplied to the plurality of modules 4 can be suppressed without lowering the output voltage of the AC power source 11, it is possible to avoid the power conversion for stepping up or down the output voltage of the AC power source 11 from operating in a region where the efficiency is reduced, and it is possible to suppress the conversion loss.

[0077] Figure 8 1 is a diagram showing an example of the correspondence relationship between the voltage and current of DC power supply 21 and the amount of power generation in charging system 10 according to the embodiment. Fig. 9 1 is a diagram showing an example of the correspondence relationship between the voltage and power of DC power supply 21 and the amount of generated power in charging system 10 according to the embodiment.

[0078] For example Figure 8 and Fig. 9 As shown, in the DC power supply 21 such as a solar cell, the current tends to decrease as the voltage increases. In this way, the power of the DC power supply 21 becomes extremely large at a specified voltage that is smaller than the open voltage OCV. For example, in the case of a solar cell, the power generation varies according to the amount of sunlight. When the power generation is relatively large, the maximum power Pa is reached at a specified voltage V1. On the other hand, when the power generation is relatively small, the maximum power Pb (<Pa) is reached at a specified voltage V2 (<V1) that is smaller than the specified voltage V1, which is smaller than the maximum power Pa.

[0079] Furthermore, if the voltage is stepped up or down by the first power conversion unit 22 in order to ensure the desired charging power for the plurality of modules 4 connected to the plurality of rectifier circuits 42 composed of a plurality of diodes connected by a bridge, using the maximum power of the DC power source 21 whose power generation varies according to the amount of sunlight, the charging efficiency of the entire system may be reduced due to the reduction in conversion efficiency. In contrast, the number of modules to be charged is changed from the plurality of modules 4 without changing the operating point of the first power conversion unit 22 according to the power generation state of the DC power source 21, thereby suppressing the reduction in the charging efficiency of the entire system.

[0080] For example, by changing the number of charging acceptance of the plurality of modules 4 with respect to the voltage of the maximum power operating point of the DC power source 21 so as to reduce the step-up and step-down conversion of the first power conversion unit 22 , efficiency can be improved.

[0081] The control device 15 partially stops charging of the plurality of modules 4 of the storage battery 1 and sequentially switches the modules 4 to be stopped for charging, thereby suppressing a decrease in charging efficiency while equally charging the plurality of modules 4 and maintaining a uniform charging state among the modules 4 .

[0082] Even when a difference in the state of charge occurs among the plurality of modules 4 , the control device 15 can easily correct the difference in the state of charge by controlling the duration of the connection state using the connection time or connection frequency of each switching circuit 41 .

[0083] (Variation)

[0084] The following describes a modification of the embodiment. The same reference numerals are used for the same parts as those in the above-mentioned embodiment, and the description thereof will be omitted or simplified.

[0085] (First Modification)

[0086] In the above-described embodiment, the AC circuit 12 may include a transformer between the AC power source 11 and the AC circuit 12 .

[0087] Fig.10 It is a diagram showing a configuration of a charging system 10A in a first modified example of the embodiment.

[0088] like Fig.10As shown, the AC circuit 12A of the charging system 10A in the first modified example includes a transformer 51 connected to the AC power source 11. The transformer 51 includes, for example, a magnetically coupled primary winding 51a and a secondary winding 51b. Both ends of the primary winding 51a are connected to the A-phase terminal AT and the B-phase terminal BT of the AC power source 11. Both ends of the secondary winding 51b are connected to the A-phase terminal 12a and the B-phase terminal 12b of the AC circuit 12A. The transformer 51 transforms the AC power output from the AC power source 11 according to the turns ratio of the primary winding 51a and the secondary winding 51b, and applies the transformed AC power to the A-phase terminal 12a and the B-phase terminal 12b.

[0089] (Second Modification)

[0090] In the above-described embodiment, the storage battery 1 may include a switch for switching between connection and disconnection at a middle position or the like of the plurality of cells 2 connected in series.

[0091] Fig.11 It is a diagram showing a configuration of a charging system 10B in a second modified example of the embodiment.

[0092] like Fig.11 As shown, the storage battery 1A in the second modification example includes a switch 52 that is mechanically switched between connection and disconnection manually or the like by an operator, for example, at an intermediate position of the plurality of cells 2 connected in series, that is, between the second module 4b and the third module 4c.

[0093] The AC circuit 12B of the charging system 10B in the second modified example includes a transformer 53 connected to the AC power source 11. The transformer 53 includes, for example, a magnetically coupled primary winding 53a and a first secondary winding 53b and a second secondary winding 53c. Both ends of the primary winding 53a are connected to the A-phase terminal AT and the B-phase terminal BT of the AC power source 11. Both ends of the first secondary winding 53b are connected to the first AC circuit 54. Both ends of the second secondary winding 53c are connected to the second AC circuit 55. The transformer 53 transforms the AC power output from the AC power source 11 according to the turns ratio between the primary winding 53a and the first secondary winding 53b and the second secondary winding 53c, and applies the transformed AC power to the first AC circuit 54 and the second AC circuit 55.

[0094] The first AC circuit 54 and the second AC circuit 55 are formed by dividing the AC circuit 12 in the above-described embodiment into two at the A-phase terminal 12 a and the B-phase terminal 12 b .

[0095] The first AC circuit 54 includes an A-phase circuit 54A and a B-phase circuit 54B, and two pairs of inductors 33. The A-phase circuit 54A and the B-phase circuit 54B respectively include a first LC column 34a and a second LC column 34b connected in series. The A-phase circuit 54A and the B-phase circuit 54B are connected to both ends of the first secondary winding 53b. The two pairs of inductors 33 are connected between the A-phase circuit 54A and the B-phase circuit 54B and the first opening and closing rectifier 14a and the second opening and closing rectifier 14b.

[0096] Ends 54 a and 54 b of the A-phase circuit 54A and the B-phase circuit 54B connected to both ends of the first secondary winding 53 b are connected to the A-phase terminal AS and the B-phase terminal BS of the first opening and closing rectifier 14 a via a pair of inductors 33 .

[0097] A connection point 31b between the first LC column 34a and the second LC column 34b of the A-phase circuit 54A is connected to the A-phase terminal AS of the second switching rectifier 14b via an inductor 33. A connection point 32b between the first LC column 34a and the second LC column 34b of the B-phase circuit 54B is connected to the B-phase terminal BS of the second switching rectifier 14b via an inductor 33.

[0098] The second AC circuit 55 includes an A-phase circuit 55A and a B-phase circuit 55B, and two pairs of inductors 33. The A-phase circuit 55A and the B-phase circuit 55B respectively include a third LC column 34c and a fourth LC column 34d connected in series. The A-phase circuit 55A and the B-phase circuit 55B are connected to both ends of the second secondary winding 53c. The two pairs of inductors 33 are connected between the A-phase circuit 55A and the B-phase circuit 55B and the third opening and closing rectifying unit 14c and the fourth opening and closing rectifying unit 14d.

[0099] Ends 55 a and 55 b of the A-phase circuit 55A and the B-phase circuit 55B connected to both ends of the second secondary winding 53 c are connected to the A-phase terminal AS and the B-phase terminal BS of the fourth opening and closing rectifier 14 d via a pair of inductors 33 .

[0100] A connection point 31c between the third LC column 34c and the fourth LC column 34d of the A-phase circuit 55A is connected to the A-phase terminal AS of the third switching rectifier 14c via an inductor 33. A connection point 32b between the third LC column 34c and the fourth LC column 34d of the B-phase circuit 55B is connected to the B-phase terminal BS of the third switching rectifier 14c via an inductor 33.

[0101] (Third Modification)

[0102] In the above-described embodiment, the opening and closing rectifier 14 includes the rectifier circuit 42 which is a full-wave rectifier circuit, but the present invention is not limited thereto and may include another rectifier circuit.

[0103] Fig.12 It is a diagram showing the configuration of a rectifier circuit 42C and an opening and closing circuit 41 of an opening and closing rectifier unit 14A in a third modification of the embodiment.

[0104] like Fig.12 As shown, the opening and closing rectifier 14A in the third modified example includes an opening and closing circuit 41 and a rectifier circuit 42C. The rectifier circuit 42C is, for example, a voltage doubling rectifier circuit. The rectifier circuit 42C includes: a first diode 42a, a second diode 42b, and a third diode 42c connected in the first column in the forward direction; a fourth diode 42d, a fifth diode 42e, and a sixth diode 42f connected in the second column in the forward direction; and four capacitors 61.

[0105] The anode of the first diode 42 a , the cathode of the second diode 42 b , and the anode of the fifth diode 42 e , and the cathode of the sixth diode 42 f are connected to the first AC terminal 42A via each of the capacitors 61 .

[0106] The anode of the second diode 42 b and the cathode of the third diode 42 c , and the anode of the fourth diode 42 d and the cathode of the fifth diode 42 e are connected to the second AC terminal 42B via each of the capacitors 61 .

[0107] The cathodes of the first diode 42a and the fourth diode 42d are connected to the positive terminal PR. The anodes of the third diode 42c and the sixth diode 42f are connected to the negative terminal NR. The positive terminal PR and the negative terminal NR of the rectifier circuit 42C are connected to the positive terminal and the negative terminal of the corresponding module 4 in the battery 1.

[0108] The rectifier circuit 42C rectifies the AC power input from the first AC terminal 42A and the second AC terminal 42B, increases the voltage amplitude of the rectified DC power to twice the voltage amplitude of the AC power, and outputs the rectified DC power from the positive terminal PR and the negative terminal NR.

[0109] (Fourth Modification and Fifth Modification)

[0110] In the above-mentioned embodiment and the third modification, the two opening and closing circuits 41 are connected between the A-phase terminal AS and the B-phase terminal BS of the opening and closing rectifier 14, 14A and the rectifier circuit 42, 42C, but the present invention is not limited thereto. The two opening and closing circuits 41 may also be connected between the positive terminal PR and the negative terminal NR of the opening and closing rectifier 14, 14A and the rectifier circuit 42, 42C.

[0111] Fig.13 It is a diagram showing the configuration of a rectifier circuit 42 and an open / close circuit 41 of an open / close rectifier unit 14B in a fourth modified example of the embodiment. Fig.14It is a diagram showing the configuration of a rectifier circuit 42C and an opening and closing circuit 41 of an opening and closing rectifier unit 14C in a fifth modification of the embodiment.

[0112] like Fig.13 and Fig.14 As shown, the opening and closing rectifier 14B of the fourth modification and the opening and closing rectifier 14C of the fifth modification respectively include two opening and closing circuits 41 which are arranged on the battery 1 side of the rectifier circuits 42 and 42C and connected to the positive terminal PR and the negative terminal NR. The collector of the first transistor 41a of each opening and closing circuit 41 is connected to the positive terminal (or negative terminal) of the rectifier circuit 42 and 42C. The collector of the second transistor 41b is connected to the positive terminal PR (or negative terminal NR).

[0113] In the above-described embodiment, the first power conversion unit 22 performs two types of power conversion, namely, voltage step-up and voltage step-down. However, the present invention is not limited thereto, and the first power conversion unit 22 may include a voltage step-up circuit or a voltage step-down circuit.

[0114] In the above-described embodiment, the charging system 10 is mounted on a vehicle, but the present invention is not limited thereto and the charging system 10 may be mounted on other equipment.

[0115] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. The above embodiments and their variations are included in the scope and purpose of the invention, and are also included in the invention recorded in the technical solution and its equivalent scope.

Claims

1. A charging system for charging a power storage device formed by connecting a plurality of power storage elements, characterized in that: The charging system comprises: AC power source; a plurality of rectifying units connected to a plurality of modules formed by dividing the power storage device into a plurality of modules, respectively, and supplying DC power obtained by rectifying the AC power supplied from the AC power source to the plurality of modules; a plurality of switch units for switching connection and disconnection between the AC power source and each of the plurality of modules; as well as a control device for controlling the connection and disconnection of the plurality of switch units according to a state quantity of at least one of an output voltage of the AC power source and an input voltage of the rectifier unit, or a state quantity associated with at least one of the output voltage and the input voltage, The control device sets an upper limit number of the plurality of opening and closing sections that are simultaneously in a connected state according to the state quantity, and sequentially switches and selects the upper limit number of the opening and closing sections that are in a connected state from among the plurality of opening and closing sections.

2. The charging system according to claim 1, characterized in that: The control device controls the time of the connection state of each of the plurality of switch parts so that the charging states of each of the plurality of modules are the same.

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