Patent Publication Number: US-2022216722-A1

Title: Charging system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Priority is claimed on Japanese Patent Application No. 2021-001663, filed Jan. 7, 2021, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a charging system. 
     Description of Related Art 
     Conventionally, for example, a power supply device for supplying electric power to a plurality of battery modules connected in series is known (refer to, for example, Japanese Unexamined Patent Application, First Publication No. 2011-67021). The power supply device includes a rectifier circuit connected to each of the plurality of battery modules, an alternating current (AC) electric line which sequentially connects a plurality of rectifier circuits to each other, and an AC generating circuit which applies an AC voltage to the AC electric line. 
     SUMMARY OF THE INVENTION 
     In the above-described conventional power supply device, since the circuit module in which the rectifier circuit and the AC electric line are integrated for each of the plurality of battery modules is formed, a device constitution is simplified by the plurality of the same circuit modules, and an increase in the cost required for the constitution can be curbed. However, the wire which connects the plurality of circuit modules to each other becomes a live-wire portion to which a direct current (DC) voltage from each of the battery modules is applied, and for example, when biting by a metal part or the like occurs, a short circuit may occur. 
     An aspect according to the present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a charging system capable of curbing occurrence of a short circuit while complexity of a device constitution is curbed. 
     In order to solve the above problems and to achieve the above object, the present invention has adopted the following aspects. 
     (1) A charging system according to one aspect of the present invention is a charging system which charges a plurality of power storage modules which form a power storage device, including an AC power source, a plurality of circuit modules connected between the AC power source and each of the plurality of power storage modules and configured to supply DC power obtained by rectifying AC power supplied from the AC power source to the plurality of power storage modules, at least one capacitor configured to disconnect a connection portion configured to connect the plurality of circuit modules from each of the plurality of power storage modules in a direct current manner. 
     (2) In the aspect (1), each of the plurality of circuit modules may include a rectifying part which rectifies the AC power, and an AC electric line which connects the AC power source to the rectifying part, and the at least one capacitor may be disposed in the AC electric line or the rectifying part. 
     (3) In the aspect (2), the plurality of circuit modules may be sequentially connected from the AC power source and may include a second capacitor disposed between the AC power source and the circuit module which is initially connected to the AC power source in addition to a first capacitor which is at least one capacitor disposed in the AC electric line. 
     According to the aspect (1), it is possible to curb the occurrence of a DC short circuit at the connection portion while maintaining the transmission of AC power by providing at least one capacitor which disconnects the connection portion connecting the plurality of circuit modules from each of the plurality of power storage modules in a direct current manner. Since the capacitor for DC interruption is provided in each of the plurality of circuit modules, a device constitution can be simplified due to the plurality of the same circuit modules corresponding to the plurality of power storage modules, and an increase in the cost required for the constitution can be curbed. 
     In the case of the aspect (2), since at least one capacitor disposed in the AC electric line or the rectifying part of each of the circuit modules is provided, it is possible to easily connect the plurality of circuit modules while they are disconnected in a direct current manner. 
     In the case of the aspect (3), since the second capacitor disposed between the AC power source and the circuit module which is initially connected to the AC power source is provided, a current gain of a resonant electric line corresponding to each of the plurality of power storage modules can be made uniform by the plurality of the same circuit modules. Thus, a system constitution is simplified, and it is possible to supply power evenly to each of the plurality of power storage modules while an increase in the cost required for the constitution is curbed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a constitution of a charging system according to an embodiment of the present invention. 
         FIG. 2  is a perspective view showing a constitution of a plurality of circuit modules and battery modules of the charging system according to the embodiment of the present invention. 
         FIG. 3  is a diagram showing a constitution of an AC power source of the charging system according to the embodiment of the present invention. 
         FIG. 4  is a diagram showing a constitution of a rectifier circuit of the charging system according to the embodiment of the present invention. 
         FIG. 5  is a diagram showing a constitution of a charging system according to a first modified example of the embodiment of the present invention. 
         FIG. 6  is a diagram showing a constitution of a charging system according to a second modified example of the embodiment of the present invention. 
         FIG. 7  is a diagram showing a constitution of a rectifier circuit of the charging system according to the second modified example of the embodiment of the present invention. 
         FIG. 8  is a diagram showing a circuit example related to the charging system according to the second modified example of the embodiment of the present invention. 
         FIG. 9  is a diagram showing an example of frequency response characteristics of a first embodiment and a second embodiment and a comparative example in the circuit example shown in  FIG. 8 . 
         FIG. 10  is a diagram showing a constitution of a rectifier circuit of a charging system according to a third modified example of the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a charging system  10  according to an embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is a diagram showing a constitution of the charging system  10  according to the embodiment.  FIG. 2  is a perspective view showing a constitution of a plurality of circuit modules  13  and battery modules  4  of the charging system  10  in the embodiment. 
     The charging system  10  according to the present embodiment is mounted in a vehicle such as an electrified vehicle. The charging system  10  is connected to a power storage device mounted in the vehicle. The electrified vehicle is an electric vehicle, a hybrid vehicle, a fuel cell vehicle, or the like. The electric vehicle is driven by a power storage device as a power source. The hybrid vehicle is driven by a power storage device and an internal combustion engine as a power source. A fuel cell vehicle is driven by a fuel cell as a power source. 
     As shown in  FIGS. 1 and 2 , the power storage device connected to the charging system  10  is, for example, a high-voltage battery  1  which is a power source for a vehicle. The battery  1  includes, for example, a string  3  formed by a plurality of cells  2  connected in series, and a positive electrode terminal and a negative electrode terminal at both ends of the string  3 . The battery  1  includes a plurality of battery modules  4  formed by dividing the string  3  into a plurality of substrings in series. The plurality of battery modules  4  are, for example, a first battery module  4   a,  a second battery module  4   b,  a third battery module  4   c,  and a fourth battery module  4   d  formed by dividing the string  3  into four parts. For example, the first battery module  4   a,  the second battery module  4   b,  the third battery module  4   c,  and the fourth battery module  4   d  are sequentially connected in series. 
     The charging system  10  includes an AC power source  11 , a plurality of circuit modules  13 , and a control device  15 . 
       FIG. 3  is a diagram showing a constitution of the AC power source  11  of the charging system  10  according to the embodiment. 
     As shown in  FIG. 3 , the AC power source  11  includes a DC power source  21 , a first power conversion part  22 , and a second power conversion part  23 . 
     The DC power source  21  is, for example, a solar cell or the like. 
     The first power conversion part  22  includes, for example, a DC-DC converter which performs two types of power conversions including stepping-up and stepping-down. The first power conversion part  22  includes a first positive electrode terminal P 1  and a first negative electrode terminal N 1 , and a second positive electrode terminal P 2  and a second negative electrode terminal N 2 . 
     The first positive electrode terminal P 1  and the first negative electrode terminal N 1  of the first power conversion part  22  are connected to a positive electrode terminal DP and a negative electrode terminal DN of the DC power source  21 . The second positive electrode terminal P 2  and the second negative electrode terminal N 2  of the first power conversion part  22  are connected to a positive electrode terminal PT and a negative electrode terminal NT of the second power conversion part  23 . 
     The first power conversion part  22  includes, for example, switching elements of a low side arm and a high side arm paired in two phases, and a reactor. Each of the switching elements is a transistor such as a metal oxide semi-conductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) and is, for example, an N-channel type MOSFET. The reactor is a choke coil L. 
     Each of the transistors may include a rectifying element. The rectifying element is a diode connected in parallel to each of the transistors. The rectifying element is, for example, a freewheeling diode connected in a forward direction from a source to a drain between the drain and the source of the MOSFET. 
     The first power conversion part  22  includes first-phase transistors S 1 H and S 1 L of the high side arm and the low side arm paired in the first phase, and second-phase transistors S 2 H and S 2 L of the high side arm and the low side arm paired in the second phase. 
     A drain of the first-phase transistor S 1 H of the high side arm is connected to the first positive electrode terminal P 1 . A drain of the second-phase transistor S 2 H of the high side arm is connected to the second positive electrode terminal P 2 . A source of the first-phase transistor S 1 L of the low side arm is connected to the first negative electrode terminal N 1 . A source of the second-phase transistor S 2 L of the low side arm is connected to the second negative electrode terminal N 2 . The source of the first-phase transistor S 1 H of the high side arm and the drain of the first-phase transistor SlL of the low side arm are connected to a first end of the two ends of the choke coil L. The source of the second-phase transistor S 2 H of the high side arm and the drain of the second-phase transistor S 2 L of the low side arm are connected to a second end of the two ends of the choke coil L. 
     The first power conversion part  22  includes a first smoothing capacitor (a capacitor) SC 1  connected between the first positive electrode terminal P 1  and the first negative electrode terminal N 1 , and a second smoothing capacitor (a capacitor) SC 2  connected between the second positive electrode terminal P 2  and the second negative electrode terminal N 2 . The first smoothing capacitor SC 1  and the second smoothing capacitor SC 2  smooth voltage fluctuations which are generated along with an on/off switching operation of each of the transistors S 1 H, S 1 L, S 2 H, and S 2 L. 
     The first power conversion part  22  switches between ON (connection) and OFF (disconnection) of each of the transistors S 1 H, S 1 L, S 2 H, and S 2 L based on a gate signal which is a switching command input to a gate of each of the transistors S 1 H, S 1 L, S 2 H, and S 2 L. 
     At the time of stepping-up, the first power conversion part  22  steps up power input from the DC power source  21  to the first positive electrode terminal P 1  and the first negative electrode terminal N 1  and outputs the stepped-up power from the second positive electrode terminal P 2  and the second negative electrode terminal N 2 . The first power conversion part  22  keeps the first-phase transistor S 1 H of the high side arm ON (connected) and the first-phase transistor SlL of the low side arm OFF (disconnected) at the time of stepping-up. 
     The first power conversion part  22  stores magnetic energy by direct current excitation of the reactor (the choke coil L) during the second-phase transistor S 2 H of the high side arm being OFF (disconnected) and the second-phase transistor S 2 L of the low side arm being ON (connected). The first power conversion part  22  generates a voltage higher than that of the first positive electrode terminal P 1  and the first negative electrode terminal N 1  at the second positive electrode terminal P 2  and the second negative electrode terminal N 2  by superimposing an induced voltage generated by magnetic energy of the reactor (the choke coil L) during the second-phase transistor S 2 H of the high side arm being ON (connected) and the second-phase transistor S 2 L of the low side arm being OFF (disconnected) on a voltage applied to the first positive electrode terminal P 1  and the first negative electrode terminal N 1 . 
     At the time of stepping-down, the first power conversion part  22  steps down power input from the first positive electrode terminal P 1  and the first negative electrode terminal N 1  and outputs the stepped-up power from the second positive electrode terminal P 2  and the second negative electrode terminal N 2 . The first power conversion part  22  keeps the second-phase transistor S 2 H of the high side arm ON (connected) and the second-phase transistor S 2 L of the low side arm OFF (disconnected) at the time of stepping-down. 
     The first power conversion part  22  stores magnetic energy by direct current excitation of the reactor (the choke coil L) upon the ON (connection) of the first-phase transistor S 1 H of the high side arm and the OFF (disconnection) of the first-phase transistor S 1 L of the low side arm. The first power conversion part  22  generates a voltage lower than that of the first positive electrode terminal P 1  and the first negative electrode terminal N 1  at the second positive electrode terminal P 2  and the second negative electrode terminal N 2  by stepping down the induced voltage generated by the magnetic energy of the reactor (the choke coil L) upon the OFF (disconnection) of the first-phase transistor S 1 H of the high side arm and the ON (connection) of the first-phase transistor SlL of the low side arm. 
     The second power conversion part  23  includes, for example, an inverter which converts the DC power input from the first power conversion part  22  into AC power and outputs the AC power to the AC electric line  12 . 
     The second power conversion part  23  includes, for example, a bridge circuit formed by a plurality of switching elements bridge-connected in two phases including an A-phase and a B-phase. The switching element is a transistor such as a MOSFET or an IGBT, and is, for example, an N-channel type MOSFET. Each of the transistors may include a rectifying element. The rectifying element is a diode connected in parallel to each of the transistors. The rectifying element is, for example, a freewheeling diode connected in the forward direction from a source to a drain between the drain and the source of the MOSFET. 
     The second power conversion part  23  includes A-phase transistors SaH and SaL of the high side arm and the low side arm paired in the A-phase, and B-phase transistors SbH and SbL of the high side arm and the low side arm paired in the B-phase. 
     Each of drains of the A-phase transistor SaH of the high side arm and the B-phase transistor SbH of the high side arm is connected to the positive electrode terminal PT. Each of sources of the A-phase transistor SaL of the low side arm and the B-phase transistor SbL of the low side arm is connected to the negative electrode terminal NT. A source of the A-phase transistor SaH of the high side arm and a drain of the A-phase transistor SaL of the low side arm are connected to an A-phase terminal AT. The source of the B-phase transistor SbH of the high side arm and the drain of the B-phase transistor SbL of the low side arm are connected to a B-phase terminal BT. 
     The second power conversion part  23  switches between ON (connection) and OFF (disconnection) of the transistor pair of each phase based on a gate signal which is a switching command input to a gate of each of the transistors SaH, SaL, SbH, and SbL. The second power conversion part  23  converts the DC power input from the positive electrode terminal PT and the negative electrode terminal NT into single-phase AC power and outputs the single-phase AC power from the A-phase terminal AT and the B-phase terminal BT. The A-phase terminal AT of the second power conversion part  23  is connected to an A-phase terminal  11 A of the AC power source  11 , and the B-phase terminal BT of the second power conversion part  23  is connected to a B-phase terminal  11 B of the AC power source  11 . 
     For example, the AC power source  11  supplies the same current (power) to each of the battery modules  4  of the battery  1  when generating an alternating current having a frequency close to a resonance frequency of an AC electric line  31  (a resonant electric line) which will be described below. 
     As shown in  FIGS. 1 and 2 , the plurality of circuit modules  13  are connected between the AC power source  11  and each of the plurality of battery modules  4 . The number of the plurality of circuit modules  13  is the same as the number of the plurality of battery modules  4 . The plurality of circuit modules  13  are, for example, a first circuit module  13   a,  a second circuit module  13   b,  a third circuit module  13   c,  and a fourth circuit module  13   d.    
     As shown in  FIG. 2 , the first battery module  4   a  and the first circuit module  13   a  are integrally connected to each other, the second battery module  4   b  and the second circuit module  13   b  are integrally connected to each other, the third battery module  4   c  and the third circuit module  13   c  are integrally connected to each other, and the fourth battery module  4   d  and the fourth circuit module  13   d  are integrally connected to each other. Each of the battery modules  4  and each of the circuit modules  13  are connected by, for example, a bus bar  17  having an insulating coating. The plurality of circuit modules  13  are sequentially connected by wires  19  from the AC power source  11 . For example, the second circuit module  13   b  and the first circuit module  13   a  are sequentially connected from the AC power source  11 , and the third circuit module  13   c  and the fourth circuit module  13   d  are sequentially connected from the AC power source  11 . 
     As shown in  FIG. 1 , each of the plurality of circuit modules  13  includes the AC electric line  31  and a rectifier circuit  33 . For example, the first circuit module  13   a  includes a first AC electric line  31   a  and a first rectifier circuit  33   a.  The second circuit module  13   b  includes a second AC electric line  31   b  and a second rectifier circuit  33   b.  The third circuit module  13   c  includes a third AC electric line  31   c  and a third rectifier circuit  33   c.  The fourth circuit module  13   d  includes a fourth AC electric line  31   d  and a fourth rectifier circuit  33   d.    
     Each of the AC electric line  31  includes an A-phase electric line  41  directly or indirectly connected to an A-phase terminal  11 A of the AC power source  11  and a B-phase electric line  43  directly or indirectly connected to a B-phase terminal  11 B of the AC power source  11 . Each of the A-phase electric line  41  and the B-phase electric line  43  includes a LC row  45  of the first capacitor (the capacitor) C 1  and the first reactor L 1  connected to each other in series on the input side of the AC power, a second capacitor (a capacitor) C 2 , and a second reactor L 2 . 
     The second capacitor C 2  and the second reactor L 2  branch at a connection point  47  provided via the LC row  45  from the input side of the AC power in the AC electric line  31  and are connected to the LC row  45 . The second capacitor C 2  is connected between the connection point  47  and the LC row  45  of the adjacent circuit module  13 . 
     For example, the second capacitor C 2  of the second circuit module  13   b  is connected between the connection point  47  of the second circuit module  13   b  and the LC row  45  of the adjacent first circuit module  13   a.    
     For example, the second capacitor C 2  of the third circuit module  13   c  is connected between the connection point  47  of the third circuit module  13   c  and the LC row  45  of the adjacent fourth circuit module  13   d.    
     The second capacitor C 2  may be omitted in the circuit module  13  (for example, each of the first circuit module  13   a  and the fourth circuit module  13   d,  or the like) disposed at the terminal among the plurality of circuit modules  13 . 
     The second capacitor C 2  disconnects the connection portion (for example, a portion of the wire  19 ) which connects the adjacent circuit modules  13  from each of the plurality of battery modules  4  in a direct current manner. 
     For example, the second capacitor C 2  of the second circuit module  13   b  disconnects the connection portion (for example, a portion of the wire  19 ) between the AC electric line  31   a  of the first circuit module  13   a  and the AC electric line  3  lb of the second circuit module  13   b  from each of the plurality of battery modules  4  in a direct current manner. 
     For example, the second capacitor C 2  of the third circuit module  13   c  disconnects the connection portion (for example, a portion of the wire  19 ) between the AC electric line  31   c  of the third circuit module  13   c  and the AC electric line  31   d  of the fourth circuit module  13   d  from each of the plurality of battery modules  4  in a direct current manner. The second reactor L 2  is connected between the connection point  47  and the rectifier circuit  33 . 
     A combination of a combined capacitance of the capacitors of the AC electric line  31  and a combined inductance of the inductors (for example, the product of the combined capacitance and the combined inductance) in each of the plurality of circuit modules  13  may be an appropriate combination. For example, when the product (the LC product) of the combined capacitance and the combined inductance of the resonant electric line for each stage corresponding to each of the battery modules  4  of the battery  1  is the same, a current gain for each of the battery modules  4  is the same, and the same current (power) is uniformly supplied to each of the battery modules  4 . 
     For example, when a first LC product with respect to the first battery module  4   a,  a second LC product with respect to the second battery module  4   b,  a third LC product with respect to the third battery module  4   c  and a fourth LC product with respect to the fourth battery module  4   d  are the same as each other, the same current (power) is uniformly supplied to each of the battery modules  4   a,    4   b,    4   c,  and  4   d.  For example, each of the LC products is the product of the combined capacitance and the combined inductance of the capacitors and the reactors other than the second reactor L 2  in each of the electric lines from the AC power source  11  to each of the rectifier circuits  33 . 
     The first LC product is the product of the combined capacitance and the combined inductance of the first capacitor C 1  and the first reactor L 1  of the first circuit module  13   a  indirectly connected to the AC power source  11  via the second circuit module  13   b,  and the first capacitor C 1 , the first reactor L 1  and the second capacitor C 2  of the second circuit module  13   b.    
     The second LC product is the product of the combined capacitance and the combined inductance of the first capacitor C 1  and the first reactor L 1  of the second circuit module  13   b  directly connected to the AC power source  11 . 
     The third LC product is the product of the combined capacitance and the combined inductance of the first capacitor C 1  and the first reactor L 1  of the third circuit module  13   c  directly connected to the AC power source  11 . 
     The fourth LC product is the product of the combined capacitance and the combined inductance of the first capacitor C 1  and the first reactor L 1  of the fourth circuit module  13   d  indirectly connected to the AC power source  11  via the third circuit module  13   c,  and the first capacitor C 1 , the first reactor L 1  and the second capacitor C 2  of the third circuit module  13   c.    
       FIG. 4  is a diagram showing a constitution of the rectifier circuit  33  of the charging system  10  according to the embodiment. 
     In each of the plurality of circuit modules  13 , the connection point  47  of the A-phase electric line  41  of the AC electric line  31  is connected to an A-phase terminal AS of the rectifier circuit  33  via the second reactor L 2 . The connection point  47  of the B-phase electric line  43  of the AC electric line  31  is connected to a B-phase terminal BS of the rectifier circuit  33  via the second reactor L 2 . 
     As shown in  FIG. 4 , the rectifier circuit  33  includes, for example, a bridge circuit formed by a plurality of diodes bridge-connected in a first row and a second row. 
     The rectifier circuit  33  is, for example, a full-wave rectifier circuit. The rectifier circuit  33  includes a first diode  51   a  and a second diode  51   b  connected in the forward direction in the first row, and a third diode  51   c  and a fourth diode  51   d  connected in the forward direction in the second row. 
     A connection point  33 A between an anode of the first diode  51   a  and a cathode of the second diode  51   b  is connected to the A-phase terminal AS. A connection point  33 B between an anode of the third diode  51   c  and a cathode of the fourth diode  51   d  is connected to the B-phase terminal BS. 
     A cathode of each of the first diode  51   a  and the third diode  51   c  is connected to a positive electrode terminal PR. An anode of each of the second diode  51   b  and the fourth diode  51   d  is connected to a negative electrode terminal NR. The positive electrode terminal PR and the negative electrode terminal NR of the rectifier circuit  42  are connected to the positive electrode terminal and the negative electrode terminal of the corresponding battery module  4  in the battery  1 . 
     The rectifier circuit  33  full-wave rectifies the AC power input from the A-phase terminal AS and the B-phase terminal BS and outputs rectified DC power from the positive electrode terminal PR and the negative electrode terminal NR. 
     As shown in  FIG. 1 , the control device  15  controls an operation of the charging system  10 . For example, the control device  15  is a software function part which functions by executing a predetermined program in a processor such as a central processing unit (CPU). The software function part is an electronic control unit (ECU) including a processor such as a CPU, a read only memory (ROM) which stores a program, a random access memory (RAM) which temporarily stores data, and an electronic circuit such as a timer. At least a part of the control device  15  may be an integrated circuit such as a large scale integration (LSI). 
     For example, the control device  15  sets a timing for driving ON (connection) and OFF (disconnection) of each of the switching elements of the AC power source  11  and actually generates a gate signal for driving the ON (connection) and OFF (disconnection) of each of the switching elements. 
     As described above, the charging system  10  of the embodiment can curb occurrence of a DC short circuit at a connection portion (for example, a portion of the wire  19 ) which connects the adjacent circuit modules  13  to each other, while the transmission of the AC power is maintained, by providing the second capacitor C 2  for DC interruption disposed in each of the A-phase electric line  41  and the B-phase electric line  43  of each of the circuit modules  13 . Thus, the adjacent circuit modules  13  can be easily connected to each other, the system constitution can be simplified, and an increase in the cost required for the constitution can be curbed. 
     It is possible to supply power evenly to each of the battery modules  4  by making the product of the combined capacitance and the combined inductance (the LC product) uniform so that a current gain of the resonant electric line corresponding to each of the battery modules  4  is the same. 
     MODIFIED EXAMPLES 
     Hereinafter, modified examples of the embodiment will be described. The same parts as those in the above-described embodiment are designated by the same reference numerals, and description thereof will be omitted or simplified. 
     First Modified Example 
     In the above-described embodiment, a capacitor for gain adjustment may be provided between the circuit module  13  directly connected to the AC power source  11  and the AC power source  11 . 
       FIG. 5  is a diagram showing a constitution of a charging system  10 A in a first modified example of the embodiment. 
     As shown in  FIG. 5 , the charging system  10 A in the first modified example includes a plurality of third capacitors (capacitors) C 3  between each of the second circuit module  13   b  and the third circuit module  13   c  directly connected to the AC power source  11  and the AC power source  11 . 
     For example, the plurality of third capacitors C 3  are four third capacitors C 3  disposed in the A-phase electric line  41  and the B-phase electric line  43  of each of the second circuit module  13   b  and the third circuit module  13   c  which is initially connected to the AC power source  11  among the plurality of circuit modules  13  which are sequentially connected from the AC power source  11 . 
     According to the first modified example, due to the third capacitor C 3  for gain adjustment provided between each of the second circuit module  13   b  and the third circuit module  13   c  directly connected to the AC power source  11  and the AC power source  11 , the current gain of the resonant electric line corresponding to each of the battery modules  4  can be made the same by the plurality of the same circuit modules  13 . Thus, the system constitution can be simplified, and power can be evenly supplied to each of the plurality of battery modules  4  while an increase in the cost required for the constitution is curbed. 
     Second Modified Example 
     In the above-described embodiment, each of the plurality of circuit modules  13  includes the second capacitor C 2  for DC interruption in the AC electric line  31 , but the present invention is not limited thereto. 
       FIG. 6  is a diagram showing a constitution of a charging system  10 B in a second modified example of the embodiment.  FIG. 7  is a diagram showing a constitution of a rectifier circuit of the charging system  10 B in the second modified example of the embodiment. 
     As shown in  FIG. 6 , the charging system  10 B of the second modified example includes an AC power source  11 , a plurality of circuit modules  13 A, and a control device  15 . The plurality of circuit modules  13 A are connected between the AC power source  11  and each of the plurality of battery modules  4 . The number of the plurality of circuit modules  13 A is the same as the number of the plurality of battery modules  4 . The plurality of circuit modules  13 A are, for example, a first circuit module  13 Aa, a second circuit module  13 Ab, a third circuit module  13 Ac, and a fourth circuit module  13 Ad. 
     Each of the plurality of circuit modules  13 A includes an AC electric line  31 A and a rectifier circuit  61 . For example, the first circuit module  13 Aa includes a first AC electric line  31 Aa and a first rectifier circuit  61   a.  The second circuit module  13 Ab includes a second AC electric line  31  Ab and a second rectifier circuit  61   b.  The third circuit module  13 Ac includes a third AC electric line  31 Ac and a third rectifier circuit  61   c.  The fourth circuit module  13 Ad includes a fourth AC electric line  31 Ad and a fourth rectifier circuit  61   d.    
     An A-phase electric line  41 A and a B-phase electric line  43 A of the AC electric line  31 A have a constitution in which the second capacitor C 2  is omitted in the A-phase electric line  41  and the B-phase electric line  43  of the AC electric line  31  of the above-described embodiment. 
     As shown in  FIG. 7 , the rectifier circuit  61  of the second modified example includes the rectifier circuit  33  of the above-described embodiment and two fourth capacitors (capacitors) C 4 . The two fourth capacitors C 4  are connected between the two connection points  33 A and  33 B and the A-phase terminal AS and the B-phase terminal BS. The two fourth capacitors C 4  disconnects the connection portion (for example, a portion of the wire  19 ) connecting the adjacent circuit modules  13 A from each of the plurality of battery modules  4  in a direct current manner. 
     According to the second modified example, the plurality of the same circuit modules  13 A can be easily connected to each other while they are disconnected in a direct current manner. The current gain of the resonant electric line corresponding to each of the battery modules  4  can be easily made the same, and the power can be evenly supplied to each of the battery modules  4 . 
     When gain characteristic changes due to the provision of the two fourth capacitors C 4 , it may be adjusted by changing other circuit components. 
     Hereinafter, frequency response characteristics in a circuit example related to the charging system  10 B of the second modified example will be described.  FIG. 8  is a diagram showing a circuit example  71  related to the charging system  10 B in the second modified example of the embodiment.  FIG. 9  is a diagram showing an example of the frequency response characteristics of the first embodiment and the second embodiment and a comparative example in the circuit example  71  shown in  FIG. 8 . 
     As shown in  FIG. 8 , the circuit example  71  in the first embodiment and the second embodiment includes a plurality of circuit modules  73  connected to a plurality of loads R, and the AC power source  11 . The plurality of loads R are, for example, four loads R having the same load resistance. The plurality of circuit modules  73  are sequentially connected from the AC power source  11 . The plurality of circuit modules  73  are, for example, a first circuit module  73   a,  a second circuit module  73   b,  a third circuit module  73   c,  and a fourth circuit module  73   d  connected between the AC power source  11  and each of the loads R. 
     Each of the plurality of circuit modules  73  includes a LC row  45  of a first capacitor (capacitor) C 1  and a first reactor L 1  connected in series on the input side of the AC power, a second reactor L 2 , and a fourth capacitor (capacitor) C 4  in each of the A-phase electric line  75  and the B-phase electric line  77  connected to the AC power source  11 . The second reactor L 2  and the fourth capacitor C 4  branch at a connection point  79  provided via the LC row  45  from the AC power input side in each of the A-phase electric line  75  and the B-phase electric line  77  and are connected to the LC row  45 . In the terminal circuit module  73  (for example, the first circuit module  73   a ) among the plurality of circuit modules  73 , the second reactor L 2  and the fourth capacitor C 4  are simply connected to the LC row  45  at each of the A-phase electric line  75  and the B-phase electric line  77  (that is, without the connection point  79  for branching). 
     The comparative example includes a constitution in which the fourth capacitor C 4  is omitted in the circuit example  71  in each of the first embodiment and the second embodiment. 
     In the first embodiment and the comparative example, a combination of the capacitance of the first capacitor C 1  and the inductance of each of the first reactor L 1  and the second reactor L 2  is the same. 
     In the first embodiment and the second embodiment, a combination of the capacitance of each of the first capacitor C 1  and the fourth capacitor C 4  and the inductance of the first reactor L 1  is the same. The inductance of the second reactor L 2  of the second embodiment is larger than the inductance of the second reactor L 2  of the first embodiment. 
     As shown in  FIG. 9 , in the first embodiment and the comparative example in which only the presence or absence of the fourth capacitor C 4  is different, a frequency at which the gains of the plurality of loads R match are the same predetermined frequency Fa. In the first embodiment, the gain at the predetermined frequency Fa is increased by providing the fourth capacitor C 4  as compared with the comparative example. That is, in the first embodiment, an amplitude (a voltage) V 1 , V 2 , V 3 , V 4  of each of the loads R at a predetermined frequency Fa is a predetermined amplitude Va, but in the comparative example, the amplitude (the voltage) V 1 , V 2 , V 3 , V 4  of each of the loads R at the predetermined frequency Fa is smaller than the predetermined amplitude Va. 
     In the second embodiment, since the inductance of the second reactor L 2  is set to be larger than that of the first embodiment, the gain is curbed, and the frequency response characteristics substantially equivalent to those of the comparative example not including the fourth capacitor C 4  can be obtained. 
     Third Modified Example 
     In the above-described embodiment and the second modified example, each of the plurality of circuit modules  13  includes the rectifier circuits  33  and  61  which are full-wave rectifier circuits, but the present invention is not limited thereto and may include other rectifier circuits. 
       FIG. 10  is a diagram showing a constitution of a rectifier circuit  61 A in a third modified example of the embodiment. 
     The rectifier circuit  61 A of the third modified example is provided in place of the rectifier circuit  61  in the charging system  10 B of the second modified example described above. 
     As shown in  FIG. 10 , the rectifier circuit  61 A of the third modified example is, for example, a voltage doubler rectifier circuit. The rectifier circuit  61 A includes a first diode  53   a,  a second diode  53   b,  and a third diode  53   c  which are connected in the forward direction in the first row, and a fourth diode  53   d,  a fifth diode  53   e,  and a sixth diode  53   f  which are connected in the forward direction in the second row, and four fifth capacitors (capacitors) C 5 . 
     An anode of the first diode  53   a  and a cathode of the second diode  53   b,  and an anode of the fifth diode  53   e  and a cathode of the sixth diode  53   f  are connected to the B-phase terminal BS via the fifth capacitors C 5 . 
     An anode of the second diode  53   b  and a cathode of the third diode  53   c,  and an anode of the fourth diode  53   d  and a cathode of the fifth diode  53   e  are connected to the A-phase terminal AS via the fifth capacitor C 5 . 
     The cathodes of the first diode  53   a  and the fourth diode  53   d  are connected to the positive electrode terminal PR. The anodes of the third diode  53   c  and the sixth diode  53   f  are connected to the negative electrode terminal NR. The positive electrode terminal PR and the negative electrode terminal NR of the rectifier circuit  61 A are connected to the positive electrode terminal and the negative electrode terminal of the corresponding module  4  in the battery  1 . 
     The rectifier circuit  61 A rectifies the AC power input from the A-phase terminal AS and the B-phase terminal BS, steps up a voltage amplitude of the rectified DC power to twice the voltage amplitude of the AC power, and outputs the voltage from the positive electrode terminal PR and the negative electrode terminal NR. 
     The four fifth capacitors C 5  disconnect the connection portion (for example, a portion of the wire  19 ) connecting the adjacent circuit modules  13 A from each of the plurality of battery modules  4  in a direct current manner. 
     According to the third modified example, it is possible to easily connect a plurality of circuit modules  13 A while they are disconnected in a direct current manner, and it is possible to improve versatility of the system. 
     In the above-described embodiment, the first power conversion part  22  performs two power conversions including stepping-up and stepping-down, but the present invention is not limited thereto, and a step-up circuit or a step-down circuit may be provided. 
     In the above-described embodiment, the charging system  10  is mounted in the vehicle, but the charging system  10  is not limited thereto and may be mounted in other devices. 
     In the above-described embodiment, the charging system  10  is connected to the power storage device, but the present invention is not limited thereto, and the charging system  10  may be connected to another load to supply power. 
     The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other types, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.