Charging System

Abstract

A charging system capable of cutting off leakage current while suppressing an increase in the cost required for the structure is provided. The charging system includes an AC power source, a plurality of rectifier circuits, a plurality of positive-side current cutoff circuits, and a control device. The plurality of rectifier circuits are connected between each of the plurality of battery modules and the AC power source. Each rectifier circuit supplies a DC power obtained by rectifying the AC power supplied from the AC power source to each battery module. The plurality of positive-side current cutoff circuits are connected between each of the plurality of battery modules and each of the plurality of rectifier circuits. Each positive-side current cutoff circuit automatically switches the conduction and cutoff of the current between each battery module and each rectifier circuit according to the AC power input to each rectifier circuit.

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 for supplying power to a plurality of battery modules connected in series (for example, see Japanese Patent Application Laid-Open No. 2011-67021). The power supply device includes a rectifier circuit connected to each of the plurality of battery modules, an AC circuit connecting the plurality of rectifier circuits in sequence, and an AC generating circuit for applying an AC voltage to the AC circuit. Summary of the invention

[0003] In the above-mentioned conventional power supply device, a rectifier circuit is provided by combining a plurality of diodes, and thus, when a diode having a small forward voltage characteristic is used to reduce loss, for example, a reverse leakage current may increase. When the leakage current of the rectifier circuit increases, the following problems may occur: discharge of the battery module occurs, and the charge amount of each of the plurality of battery modules becomes uneven.

[0004] In order to solve such problems, for example, when adding a relay having mechanical contacts, the following problems will arise: there are restrictions on mechanical operation assurance, and the contact parts are easily degraded due to the inrush current when connected or the arc when disconnected. In the case of adding, for example, an optical coupler or an insulating DC-DC converter to cope with the situation that the potentials of multiple battery modules connected in series are different from each other, the cost required for the device structure will increase.

[0005] 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 cutting off leakage current while suppressing an increase in cost required for the structure.

[0006] In order to solve the above problems and achieve the relevant objects, the present invention adopts the following means.

[0007] (1) A charging system according to one embodiment of the present invention charges a plurality of storage modules forming a storage device, and is characterized in that the charging system comprises: an AC power source; a plurality of rectifier units, which are connected between each of the plurality of storage modules and the AC power source and supply DC power obtained by rectifying the AC power supplied from the AC power source to the plurality of storage modules; and a plurality of current cutoff units, which are connected between each of the plurality of storage modules and each of the plurality of rectifier units and automatically switch on and off the current between the plurality of storage modules and the plurality of rectifier units according to the AC power respectively input to the plurality of rectifier units.

[0008] (2) Based on the above scheme (1), the multiple current cut-off parts may respectively include: a switch part, which is connected between the power storage module and the rectifier part and has at least one switching element; and a drive part, which is connected between the AC input end of the rectifier part and the control terminal of the switch part and generates a control signal for switching the opening and closing of the switch part according to the AC power input to the AC input end.

[0009] (3) In the above scheme (2), the driving unit may include: a capacitor connected to the AC input terminal; a rectifier circuit connected to the capacitor; and a discharge resistor connected between the rectifier circuit and the switch unit.

[0010] According to the above scheme (1), a plurality of current cut-off units are provided for automatically switching on and off the current between the plurality of power storage modules and the plurality of rectifier units according to the AC power input to each rectifier unit. This can suppress an increase in the cost required for the structure while suppressing an increase in the leakage current of the power storage module flowing through the rectifier unit.

[0011] In the case of the above-mentioned solution (2), a driving unit that automatically switches the switching element on (conduction) and off (disconnection) is provided, thereby suppressing an increase in the leakage current of the power storage module flowing through the rectifying unit while suppressing an increase in the cost required for the structure.

[0012] In the case of the above scheme (3), the conduction and disconnection of the current can be automatically switched according to whether AC power is applied or not. When AC power is not flowing, the switch element is disconnected by the discharge of the discharge resistor, and when AC power is flowing, the potential of the control terminal of the switch unit increases and the switch element is turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a diagram showing the configuration of a charging system in an embodiment of the present invention.

[0014] 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.

[0015] Figure 3 It is a diagram showing the configuration of a rectifier circuit of a charging system in an embodiment of the present invention.

[0016] Figure 4 It is a diagram showing the configuration of a positive electrode side current interruption circuit of a charging system in an embodiment of the present invention.

[0017] Figure 5This is a diagram showing an example of changes in the charging current, the source-gate potential, and the AC voltage amplitude in the charging system according to the embodiment of the present invention.

[0018] Figure 6 It is a diagram showing the configuration of a charging system in a first modified example of the embodiment of the present invention.

[0019] Figure 7 It is a diagram showing a configuration of a negative electrode side current interruption circuit of a charging system in a first modified example of the embodiment of the present invention.

[0020] Figure 8 It is a diagram showing a configuration of a charging system in a second modified example of the embodiment of the present invention.

[0021] Fig. 9 It is a diagram showing the configuration of a positive electrode side current interruption circuit and a negative electrode side current interruption circuit of a charging system in a second modified example of the embodiment of the present invention.

[0022] Fig.10 It is a diagram showing a configuration of a positive electrode side current interruption circuit of a charging system in a third modified example of the embodiment of the present invention. DETAILED DESCRIPTION

[0023] Hereinafter, a charging system 10 according to an embodiment of the present invention will be described with reference to the drawings.

[0024] Figure 1 It is a diagram showing the configuration of charging system 10 in the embodiment.

[0025] 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.

[0026] like Figure 1 As shown, the power storage device connected to the charging system 10 is, for example, a high-voltage battery 1 that serves as a power source for the vehicle. The battery 1 includes, for example, 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 battery modules 4 formed by dividing the string 3 into a plurality of substrings connected in series. The plurality of battery modules 4 are, for example, a first battery module 4a, a second battery module 4b, a third battery module 4c, and a fourth battery module 4d formed by dividing the string 3 into four parts. For example, the first battery module 4a, the second battery module 4b, the third battery module 4c, and the fourth battery module 4d are connected in series in sequence.

[0027] The charging system 10 includes an AC power source 11 , a plurality of circuit modules 13 , and a control device 15 .

[0028] Figure 2 1 is a diagram showing a configuration of an AC power source 11 of a charging system 10 according to the embodiment.

[0029] 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 .

[0030] The DC power source 21 is, for example, a solar cell or the like.

[0031] The first power conversion unit 22 includes, for example, a DC-DC converter that performs two types of power conversion, namely, voltage step-up and voltage step-down. The first power conversion unit 22 includes a first positive terminal P1 and a first negative terminal N1 and a second positive terminal P2 and a second negative terminal N2.

[0032] 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.

[0033] The first power conversion unit 22 includes, for example, a reactor and switching elements of a low-side arm and a high-side arm that form a pair in two phases. The switching element is a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), for example, an N-channel MOSFET. The reactor is a choke coil L.

[0034] Each transistor may also include a rectifier element. The rectifier element is a diode connected in parallel with each transistor. The rectifier element is, for example, a freewheeling diode connected in a forward direction from the source to the drain between the drain and source of the MOSFET.

[0035] The first power conversion unit 22 includes first-phase transistors S1H and S1L forming a pair of high-side and low-side arms in the first phase, and second-phase transistors S2H and S2L forming a pair of high-side and low-side arms in the second phase.

[0036] The drain of the high-side arm first-phase transistor S1H is connected to the first positive terminal P1. The drain of the high-side arm second-phase transistor S2H is connected to the second positive terminal P2. The source of the low-side arm first-phase transistor S1L is connected to the first negative terminal N1. The source of the low-side arm second-phase transistor S2L is connected to the second negative terminal N2. The source of the high-side arm first-phase transistor S1H and the drain 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 source of the high-side arm second-phase transistor S2H and the drain of the low-side arm second-phase transistor S2L are connected to the second ends of the two ends of the choke coil L.

[0037] The first power conversion unit 22 includes a first smoothing capacitor (capacitor) SC1 connected between the first positive terminal P1 and the first negative terminal N1, and a second smoothing capacitor (capacitor) SC2 connected between the second positive terminal P2 and the second negative terminal N2. The first smoothing capacitor SC1 and the second smoothing capacitor SC2 smooth the voltage fluctuation caused by the switching operation of turning on / off of each transistor S1H, S1L, S2H, and S2L.

[0038] The first power conversion unit 22 switches the transistors S1H, S1L, S2H, and S2L on (conducting) and off (disconnecting) based on a gate signal which is a switching command input from the gate of each transistor S1H, S1L, S2H, and S2L.

[0039] When boosting, the first power conversion unit 22 boosts the power input from the first positive terminal P1 and the first negative terminal N1 of the DC power supply 21, and outputs the boosted power from the second positive terminal P2 and the second negative terminal N2. When boosting, the first power conversion unit 22 maintains the high-side arm first-phase transistor S1H turned on (conducting) and the low-side arm first-phase transistor S1L turned off (disconnected).

[0040] The first power conversion unit 22 accumulates magnetic energy by DC excitation of the reactor (choke coil L) when the high-side arm second-phase transistor S2H is disconnected (cut off) and the low-side arm second-phase transistor S2L is connected (conducted). The first power conversion unit 22 generates a higher voltage at the second positive terminal P2 and the second negative terminal N2 than the first positive terminal P1 and the first negative terminal N1 by superimposing the induced voltage generated by the magnetic energy of the reactor (choke coil L) when the high-side arm second-phase transistor S2H is connected (conducted) and the low-side arm second-phase transistor S2L is disconnected (cut off) on the voltage applied to the first positive terminal P1 and the first negative terminal N1.

[0041] The first power conversion unit 22 reduces the voltage of the power input from the first positive terminal P1 and the first negative terminal N1, and outputs the reduced voltage 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) when reducing the voltage.

[0042] The first power conversion unit 22 accumulates magnetic energy by DC 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).

[0043] 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 .

[0044] The second power conversion unit 23, for example, includes a bridge circuit formed by a plurality of switching elements connected in a bridge in two phases, namely, phase A and phase B. The switching element is a transistor such as a MOSFET or an IGBT, for example, an N-channel MOSFET. Each transistor may also include a rectifier element. The rectifier element is a diode connected in parallel with each transistor. The rectifier element is, for example, a freewheeling diode connected in a forward direction from the source to the drain between the drain and source of the MOSFET.

[0045] The second power conversion unit 23 includes A-phase transistors SaH and SaL forming a pair of high-side arm and low-side arm in the A-phase and B-phase transistors SbH and SbL forming a pair of high-side arm and low-side arm in the B-phase.

[0046] The drains 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 sources 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 source of the high-side arm A-phase transistor SaH and the drain of the low-side arm A-phase transistor SaL are connected to the A-phase terminal AT. The source of the high-side arm B-phase transistor SbH and the drain of the low-side arm B-phase transistor SbL are connected to the B-phase terminal BT.

[0047] 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 11A of the AC power source 11, and the B-phase terminal BT of the second power conversion unit 23 is connected to the B-phase terminal 11B of the AC power source 11.

[0048] The AC power source 11 supplies the same current (power) to each battery module 4 of the battery 1 when generating AC with a frequency close to the resonance frequency of an AC circuit 31 (resonance circuit) described later, for example.

[0049] like Figure 1 As shown, the plurality of circuit modules 13 are connected between each of the plurality of battery modules 4 and the AC power source 11. 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 13a, a second circuit module 13b, a third circuit module 13c, and a fourth circuit module 13d.

[0050] For example, the first battery module 4a and the first circuit module 13a are connected as a whole, the second battery module 4b and the second circuit module 13b are connected as a whole, the third battery module 4c and the third circuit module 13c are connected as a whole, and the fourth battery module 4d and the fourth circuit module 13d are connected as a whole. Each battery module 4 and each circuit module 13 are connected, for example, by a busbar (not shown) having an insulating coating. The plurality of circuit modules 13 are connected in sequence from the AC power source 11 by wiring (not shown). For example, the second circuit module 13b and the first circuit module 13a are connected in sequence from the AC power source 11, and the third circuit module 13c and the fourth circuit module 13d are connected in sequence from the AC power source 11.

[0051] like Figure 1 As shown, the plurality of circuit modules 13 are respectively provided with an AC circuit 31, a rectifier circuit 33, and a positive-side current cutoff circuit 35. For example, the first circuit module 13a is provided with a first AC circuit 31a, a first rectifier circuit 33a, and a first positive-side current cutoff circuit 35a. The second circuit module 13b is provided with a second AC circuit 31b, a second rectifier circuit 33b, and a second positive-side current cutoff circuit 35b. The third circuit module 13c is provided with a third AC circuit 31c, a third rectifier circuit 33c, and a third positive-side current cutoff circuit 35c. The fourth circuit module 13d is provided with a fourth AC circuit 31d, a fourth rectifier circuit 33d, and a fourth positive-side current cutoff circuit 35d.

[0052] Each AC circuit 31 includes an A-phase circuit 41 directly or indirectly connected to the A-phase terminal 11A of the AC power source 11 and a B-phase circuit 43 directly or indirectly connected to the B-phase terminal 11B of the AC power source 11. The A-phase circuit 41 and the B-phase circuit 43 each include an LC column 45 of a first capacitor (capacitor) C1 and a first inductor L1 connected in series on the input side of the AC power, and a second inductor L2.

[0053] The second reactor L2 is connected between a first connection point 47 provided from the input side of the AC power through the LC column 45 and a second connection point 49 on the rectifier circuit 33 side in the AC circuit 31. The second connection point 49 is connected to the second reactor L2, the rectifier circuit 33 and the positive current interruption circuit 35.

[0054] The combination of the combined capacitance of the capacitors and the combined inductance of the inductors in the AC circuits 31 in each of the plurality of circuit modules 13 (for example, the product of the combined capacitance and the combined inductance) may be appropriately combined. For example, when the product of the combined capacitance and the combined inductance (LC product) of the resonant circuits of each segment corresponding to each of the battery modules 4 of the battery 1 is the same, the 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.

[0055] For example, when the first LC product for the first battery module 4a, the second LC product for the second battery module 4b, the third LC product for the third battery module 4c, and the fourth LC product for the fourth battery module 4d are the same, the same current (power) is uniformly supplied to each battery module 4a, 4b, 4c, 4d. For example, each LC product is the product of the composite capacitance and composite inductance formed by the capacitors and reactors other than the second reactor L2 in each circuit from the AC power source 11 to each rectifier circuit 33.

[0056] The first LC product is the product of the combined capacitance and combined inductance formed by the first capacitor C1 and the first reactor L1 of the first circuit module 13a indirectly connected to the AC power source 11 via the second circuit module 13b, and the first capacitor C1 and the first reactor L1 of the second circuit module 13b.

[0057] The second LC product is the product of the combined capacitance and the combined inductance formed by the first capacitor C1 and the first reactor L1 of the second circuit module 13 b directly connected to the AC power source 11 .

[0058] The third LC product is the product of the combined capacitance and the combined inductance formed by the first capacitor C1 and the first reactor L1 of the third circuit module 13 c directly connected to the AC power source 11 .

[0059] The fourth LC product is the product of the combined capacitance and combined inductance formed by the first capacitor C1 and the first reactor L1 of the fourth circuit module 13d indirectly connected to the AC power source 11 via the third circuit module 13c, and the first capacitor C1 and the first reactor L1 of the third circuit module 13c.

[0060] The rectifier circuit 33 of each of the plurality of circuit modules 13 is connected between the AC circuit 31 and the corresponding battery module 4 in the battery 1. In each of the plurality of circuit modules 13, the second connection point 49 of the A-phase circuit 41 of the AC circuit 31 is connected to the A-phase terminal AS of the rectifier circuit 33. The second connection point 49 of the B-phase circuit 43 of the AC circuit 31 is connected to the B-phase terminal BS of the rectifier circuit 33.

[0061] Figure 3 1 is a diagram showing a configuration of a rectifier circuit 33 of a charging system 10 according to the embodiment.

[0062] like Figure 3 As shown, the rectifier circuit 33 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.

[0063] The rectifier circuit 33 is, for example, a full-wave rectifier circuit and includes a first diode 51 a and a second diode 51 b connected in the first column in the forward direction, and a third diode 51 c and a fourth diode 51 d connected in the second column in the forward direction.

[0064] A connection point 33A between the anode of the first diode 51a and the cathode of the second diode 51b is connected to the A-phase terminal AS. A connection point 33B between the anode of the third diode 51c and the cathode of the fourth diode 51d is connected to the B-phase terminal BS.

[0065] The cathodes of the first diode 51a and the third diode 51c are connected to the positive terminal PR. The anodes of the second diode 51b and the fourth diode 51d 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 battery module 4 in the battery 1.

[0066] The rectifier circuit 33 performs full-wave rectification on the AC power input from the A-phase terminal AS and the B-phase terminal BS, and outputs the rectified DC power from the positive terminal PR and the negative terminal NR.

[0067] Figure 4 1 is a diagram showing a configuration of the positive electrode side current interruption circuit 35 of the charging system 10 in the embodiment.

[0068] like Figure 4As shown, the positive current interruption circuit 35 of each of the plurality of circuit modules 13 is connected between the rectifier circuit 33 and the positive terminal of the corresponding battery module 4 in the battery 1. The positive current interruption circuit 35 includes a positive switch unit 61 and a positive switch driving unit 63.

[0069] The positive side switch unit 61 is connected between the positive terminal PR of the rectifier circuit 33 and the positive terminal of the corresponding battery module 4 in the battery 1. The positive side switch unit 61 is, for example, a bidirectional switch formed by two switching elements. The switching element is a transistor such as a MOSFET or an IGBT, for example, an N-channel MOSFET. Each transistor may also have a rectifier element. The rectifier element is a diode connected in parallel with each transistor. The rectifier element is, for example, a freewheeling diode connected in the forward direction from the source to the drain between the drain and source of the MOSFET.

[0070] The positive electrode side switch unit 61 includes a positive electrode side first transistor 61 a and a positive electrode side second transistor 61 b ​​which are connected in reverse series.

[0071] The gates G of the first positive-side transistor 61a and the second positive-side transistor 61b are connected to the positive terminal of the positive-side switch driving unit 63 (e.g., the connection point 65P of the positive-side rectifier circuit 65 described later). The sources of the first positive-side transistor 61a and the second positive-side transistor 61b are connected to the negative terminal of the positive-side switch driving unit 63 (e.g., the connection point 65N of the positive-side rectifier circuit 65 described later). The drain of the first positive-side transistor 61a is connected to the positive terminal of the corresponding battery module 4 in the battery 1. The drain of the second positive-side transistor 61b is connected to the positive terminal PR of the rectifier circuit 33.

[0072] The positive-side switch unit 61 switches the connection (conduction) / disconnection (cut-off) of the first positive-side transistor 61a and the second positive-side transistor 61b based on the switching command, i.e., the gate signal, generated by the voltage applied between the gate and source of each of the first positive-side transistor 61a and the second positive-side transistor 61b from the positive-side switch driving unit 63. The positive-side switch unit 61 switches the conduction and cut-off of the current between each battery module 4 and the rectifier circuit 33 by turning on (conduction) / disconnection (cut-off) the first positive-side transistor 61a and the second positive-side transistor 61b.

[0073] The positive-side switch driving unit 63 includes two positive-side capacitors (capacitors) CP for DC insulation, a positive-side rectifying circuit 65 , and a positive-side resistor RP for discharge.

[0074] The two positive electrode side capacitors CP are connected to the second connection points 49 of the A-phase circuit 41 and the B-phase circuit 43 of the AC circuit 31 .

[0075] The positive-side rectifying circuit 65 includes, for example, a bridge circuit formed of a plurality of diodes connected in a bridge in two columns, namely, a first column and a second column.

[0076] The positive side rectifier circuit 65 is, for example, a full-wave rectifier circuit and includes a first positive side diode 65a and a second positive side diode 65b connected in forward direction in the first column, and a third positive side diode 65c and a fourth positive side diode 65d connected in forward direction in the second column.

[0077] A connection point (A-phase connection point) 65A where the anode of the first positive-side diode 65a and the cathode of the second positive-side diode 65b are connected is connected to the second connection point 49 of the A-phase circuit 41 via the positive-side capacitor CP. A connection point (B-phase connection point) 65B where the anode of the third positive-side diode 65c and the cathode of the fourth positive-side diode 65d are connected is connected to the second connection point 49 of the B-phase circuit 43 via the positive-side capacitor CP.

[0078] A connection point 65P of the cathodes of the first positive-side diode 65a and the third positive-side diode 65c is connected to the gates G of the transistors 61a and 61b of the positive-side switch section 61. A connection point 65N of the anodes of the second positive-side diode 65b and the fourth positive-side diode 65d is connected to the sources of the transistors 61a and 61b of the positive-side switch section 61.

[0079] Positive-side rectifier circuit 65 full-wave rectifies AC power input from A-phase circuit 41 and B-phase circuit 43 to A-phase connection point 65A and B-phase connection point 65B, and outputs the rectified DC power from connection point 65P and connection point 65N.

[0080] The positive electrode side resistor RP is connected between the connection point 65P and the connection point 65N of the positive electrode side rectifying circuit 65 .

[0081] The positive-side switch driving unit 63 automatically switches the conduction and interruption of the current of the positive-side switch unit 61 according to the AC power input from the A-phase circuit 41 and the B-phase circuit 43 to the rectifier circuit 33 .

[0082] The positive side switch driving unit 63 first discharges the charge between the gate and source of each transistor 61a, 61b of the positive side switch unit 61 using the positive side resistor RP for discharge when no AC power is flowing in the AC circuit 31, thereby each transistor 61a, 61b is in a cut-off state, and the leakage current of the battery module 4 flowing through the rectifier circuit 33 is extremely small.

[0083] When the AC power source 11 is started and AC power is applied from the AC circuit 31 to the positive-side switch driving unit 63, only the AC component is input to the positive-side rectifier circuit 65 via the positive-side capacitor CP. The DC power rectified by the positive-side rectifier circuit 65 is used to charge the gate-source capacitance of each transistor 61a, 61b of the positive-side switch unit 61. When the gate-source potential becomes sufficiently high, each transistor 61a, 61b is turned on and the DC power generated by the rectifier circuit 33 is charged into the battery module 4.

[0084] When the AC power source 11 stops and the AC power of the AC circuit 31 is cut off, the transistors 61a and 61b of the positive electrode switch unit 61 are turned off again, and the leakage current of the battery module 4 flowing through the rectifier circuit 33 becomes extremely small.

[0085] Figure 5 1 is a diagram showing an example of changes in the charging current, the source-gate potential, and the AC voltage amplitude in the charging system 10 according to the embodiment.

[0086] like Figure 5 As shown in FIG. 1 , as the amplitude of the AC voltage increases, for example, after time t1 , the potential between the source and the gate of each transistor 61 a , 61 b ​​of the positive-side switch unit 61 changes in an increasing trend.

[0087] Then, as shown after time t2, after the amplitude of the AC voltage reaches the specified amplitude Vb and the source-gate potential of each transistor 61a, 61b reaches the specified potential Va, each transistor 61a, 61b of the positive side switch unit 61 turns on, and the specified charging current Ia flows in the battery module 4.

[0088] Then, as shown after time t3, the amplitude of the AC voltage decreases from the predetermined amplitude Vb, thereby decreasing the charging current of the battery module 4 from the predetermined charging current Ia. Accordingly, as shown after time t4, the source-gate potential of each transistor 61a, 61b decreases from the predetermined potential Va.

[0089] Then, as shown at time t5 , the amplitude of the AC voltage and the charging current of the battery module 4 reach zero, the source-gate potential of each transistor 61 a , 61 b ​​decreases, and each transistor 61 a , 61 b ​​of the positive-side switch unit 61 is turned off.

[0090] As described above, each of the transistors 61 a and 61 b ​​is automatically turned on by application of the AC power, and each of the transistors 61 a and 61 b ​​is automatically turned off by stopping the AC power.

[0091] like Figure 1As shown in FIG. 1 , 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 its 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) that includes a processor such as a CPU, a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, and electronic circuits such as a timer. At least a part of the control device 15 may also be an integrated circuit such as an LSI (Large Scale Integration).

[0092] For example, the control device 15 sets the timing for driving each switching element of the AC power source 11 to turn on (conduct) / off (cut off), and generates a gate signal for actually driving each switching element to turn on (conduct) / off (cut off).

[0093] As described above, the charging system 10 of the embodiment has a positive-side current cut-off circuit 35, which automatically switches the conduction and cut-off of the current between the battery module 4 and the rectifier circuit 33 according to the AC power input to the rectifier circuit 33, thereby suppressing the increase in the leakage current of the battery module 4 flowing through the rectifier circuit 33 while suppressing the increase in the cost required for the structure.

[0094] The positive-side current cut-off circuit 35 includes a positive-side switch driving unit 63, which automatically switches the on (conduction) / off (cut-off) of each transistor 61a, 61b of the positive-side switch unit 61, thereby suppressing the increase in the cost required for the structure compared to the case of adding, for example, an optocoupler or an insulating DC-DC converter.

[0095] The positive side switch driving unit 63 can automatically switch the conduction and cutoff of the current of the positive side switch unit 61 according to whether or not AC power is applied. When AC power is not passed, the discharge of the positive side resistor RP cuts off each transistor 61a, 61b, and when AC power is passed, the gate-source potential of each transistor 61a, 61b increases and each transistor 61a, 61b is turned on.

[0096] (Variation Example)

[0097] 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.

[0098] (First Modification)

[0099] In the above-described embodiment, each of the plurality of circuit modules 13 includes the positive electrode current interruption circuit 35 between the rectifier circuit 33 and the positive terminal of the battery module 4 , but the present invention is not limited thereto.

[0100] Figure 6 It is a diagram showing a configuration of a charging system 10A in a first modified example of the embodiment. Figure 7 1 is a diagram showing a configuration of a negative electrode current interruption circuit 37 of a charging system 10A in a first modified example of the embodiment.

[0101] like Figure 6 As shown, the charging system 10A in the first modification includes an AC power source 11, a plurality of circuit modules 13A, and a control device 15. The plurality of circuit modules 13A 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 13A is the same as the number of the plurality of battery modules 4. The plurality of circuit modules 13A are, for example, a first circuit module 13Aa, a second circuit module 13Ab, a third circuit module 13Ac, and a fourth circuit module 13Ad.

[0102] The plurality of circuit modules 13A each include an AC circuit 31, a rectifier circuit 33, and a negative-side current cutoff circuit 37. For example, the first circuit module 13Aa includes a first AC circuit 31a, a first rectifier circuit 33a, and a first negative-side current cutoff circuit 37a. The second circuit module 13Ab includes a second AC circuit 31b, a second rectifier circuit 33b, and a second negative-side current cutoff circuit 37b. The third circuit module 13Ac includes a third AC circuit 31c, a third rectifier circuit 33c, and a third negative-side current cutoff circuit 37c. The fourth circuit module 13Ad includes a fourth AC circuit 31d, a fourth rectifier circuit 33d, and a fourth negative-side current cutoff circuit 37d.

[0103] like Figure 7 As shown, the negative current cutoff circuit 37 of each of the plurality of circuit modules 13A is connected between the rectifier circuit 33 and the negative terminal of the corresponding battery module 4 in the battery 1. The negative current cutoff circuit 37 includes a negative switch unit 71 and a negative switch driver 73.

[0104] The negative side switch unit 71 is connected between the negative terminal NR of the rectifier circuit 33 and the negative terminal of the corresponding battery module 4 in the battery 1. The negative side switch unit 71 is, for example, a bidirectional switch formed by two switching elements. The switching element is a transistor such as a MOSFET or an IGBT, for example, an N-channel MOSFET. Each transistor may also have a rectifier element. The rectifier element is a diode connected in parallel with each transistor. The rectifier element is, for example, a freewheeling diode connected in the forward direction from the source to the drain between the drain and source of the MOSFET.

[0105] The negative electrode side switch unit 71 includes a negative electrode side first transistor 71 a and a negative electrode side second transistor 71 b which are connected in reverse series.

[0106] The gates G of the first negative-side transistor 71a and the second negative-side transistor 71b are connected to the positive terminal of the negative-side switch driving unit 73 (e.g., the connection point 75P of the negative-side rectifier circuit 75 described later). The sources of the first negative-side transistor 71a and the second negative-side transistor 71b are connected to the negative terminal of the negative-side switch driving unit 73 (e.g., the connection point 75N of the negative-side rectifier circuit 75 described later). The drain of the first negative-side transistor 71a is connected to the negative terminal NR of the rectifier circuit 33. The drain of the second negative-side transistor 71b is connected to the negative terminal of the corresponding battery module 4 in the battery 1.

[0107] The negative-side switch unit 71 switches the connection (conduction) / disconnection (cutoff) of the first negative-side transistor 71a and the second negative-side transistor 71b based on the switching command, i.e., the gate signal, generated by the voltage applied between the gate and source of each of the negative-side switch driving unit 73. The negative-side switch unit 71 switches the conduction and cutoff of the current between each battery module 4 and the rectifier circuit 33 by turning on (conduction) / disconnection (cutoff) of the first negative-side transistor 71a and the second negative-side transistor 71b.

[0108] The negative electrode side switch driving unit 73 includes two negative electrode side capacitors (capacitors) CN for DC insulation, a negative electrode side rectifying circuit 75 , and a negative electrode side resistor RN for discharge.

[0109] The two negative electrode side capacitors CN are connected to the second connection points 49 of the A-phase circuit 41 and the B-phase circuit 43 of the AC circuit 31 .

[0110] The negative electrode side rectifier circuit 75 includes, for example, a bridge circuit formed of a plurality of diodes bridge-connected in two columns, namely, a first column and a second column.

[0111] The negative-side rectifier circuit 75 is, for example, a full-wave rectifier circuit and includes a first negative-side diode 75a and a second negative-side diode 75b connected in the first column, and a third negative-side diode 75c and a fourth negative-side diode 75d connected in the second column.

[0112] A connection point (A phase connection point) 75A where the anode of the first negative-side diode 75a and the cathode of the second negative-side diode 75b are connected is connected to the second connection point 49 of the A phase circuit 41 via the negative-side capacitor CN. A connection point (B phase connection point) 75B where the anode of the third negative-side diode 75c and the cathode of the fourth negative-side diode 75d are connected is connected to the second connection point 49 of the B phase circuit 43 via the negative-side capacitor CN.

[0113] A connection point 75P of the cathodes of the first negative-side diode 75a and the third negative-side diode 75c is connected to the gates G of the transistors 71a and 71b of the negative-side switch section 71. A connection point 75N of the anodes of the second negative-side diode 75b and the fourth negative-side diode 75d is connected to the sources of the transistors 71a and 71b of the negative-side switch section 71.

[0114] Negative-side rectifier circuit 75 full-wave rectifies AC power input from A-phase circuit 41 and B-phase circuit 43 to A-phase connection point 75A and B-phase connection point 75B, and outputs the rectified DC power from connection point 75P and connection point 75N.

[0115] The negative electrode side resistor RN is connected between the connection point 75P and the connection point 75N of the negative electrode side rectifying circuit 75 .

[0116] The negative-side switch driving unit 73 automatically switches the conduction and interruption of the current of the negative-side switch unit 71 according to the AC power input from the A-phase circuit 41 and the B-phase circuit 43 to the rectifier circuit 33 .

[0117] (Second Modification)

[0118] In the above-described embodiment or first modification, the plurality of circuit modules 13 include a positive electrode current interruption circuit 35 or a negative electrode current interruption circuit 37 between the rectifier circuit 33 and the positive terminal or negative terminal of the battery module 4 , but the present invention is not limited thereto.

[0119] Figure 8 It is a diagram showing a configuration of a charging system 10B in a second modified example of the embodiment. Fig. 9 1 is a diagram showing the configuration of a positive electrode current interruption circuit 35 and a negative electrode current interruption circuit 37 of a charging system 10B in a second modified example of the embodiment.

[0120] like Figure 8 and Fig. 9As shown, the charging system 10B in the second modification example includes an AC power source 11, a plurality of circuit modules 13B, and a control device 15. The plurality of circuit modules 13B 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 13B is the same as the number of the plurality of battery modules 4. The plurality of circuit modules 13B are, for example, a first circuit module 13Ba, a second circuit module 13Bb, a third circuit module 13Bc, and a fourth circuit module 13Bd. The plurality of circuit modules 13B each include an AC circuit 31, a rectifier circuit 33, a positive-side current cutoff circuit 35, and a negative-side current cutoff circuit 37. For example, the first circuit module 13Ba includes a first AC circuit 31a, a first rectifier circuit 33a, a first positive-side current cutoff circuit 35a, and a first negative-side current cutoff circuit 37a. The second circuit module 13Bb includes a second AC circuit 31b, a second rectifier circuit 33b, a second positive-side current cutoff circuit 35b, and a second negative-side current cutoff circuit 37b. The third circuit module 13Bc includes a third AC circuit 31c, a third rectifier circuit 33c, a third positive-side current cutoff circuit 35c, and a third negative-side current cutoff circuit 37c. The fourth circuit module 13Bd includes a fourth AC circuit 31d, a fourth rectifier circuit 33d, a fourth positive-side current cutoff circuit 35d, and a fourth negative-side current cutoff circuit 37d.

[0121] (Third Modification)

[0122] In the above-described embodiment, the positive electrode side current interruption circuit 35 of each of the plurality of circuit modules 13 includes a bridge circuit formed of a plurality of diodes, but the present invention is not limited thereto and other rectification circuits may be included.

[0123] Fig.10 1 is a diagram showing a configuration of a positive electrode side current interruption circuit 35A of a charging system 10C in a third modified example of the embodiment.

[0124] like Fig.10 As shown, the positive-side current cutoff circuit 35A of the charging system 10C in the third modification includes a positive-side switch unit 61 and a positive-side switch driver 63A. The positive-side switch driver 63A includes two negative-side capacitors (capacitors) CN for DC insulation, a positive-side rectifier circuit 81, and a positive-side resistor RP for discharge.

[0125] The positive-side rectifying circuit 81 includes, for example, a first diode 81 a , a second diode 81 b , and a third diode 81 c .

[0126] The cathode of the first diode 81 a is connected to the positive-side capacitor CP on the A-phase side, and the anode of the first diode 81 a is connected to the positive-side capacitor CP on the B-phase side.

[0127] The cathode of the second diode 81 b is connected to the gates G of the transistors 61 a and 61 b ​​of the positive-side switch unit 61 , and the anode of the second diode 81 b is connected to the cathode of the first diode 81 a .

[0128] The cathode of the third diode 81 c is connected to the anode of the first diode 81 a , and the anode of the third diode 81 c is connected to the sources of the transistors 61 a and 61 b ​​of the positive-side switch unit 61 .

[0129] 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.

[0130] 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.

[0131] In the above-described embodiment, charging system 10 is connected to a power storage device, but the present invention is not limited thereto, and charging system 10 may be connected to another load to supply electric power.

[0132] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the main purpose of the invention. These embodiments and their variations are included in the scope and main 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 plurality of power storage modules connected in series to form a power storage device, characterized in that: The charging system comprises: AC power source; a plurality of rectifiers connected between each of the plurality of power storage modules and the AC power source and supplying DC power obtained by rectifying the AC power supplied from the AC power source to the plurality of power storage modules; and a plurality of current cut-off units connected between each of the plurality of power storage modules and each of the plurality of rectifier units, and automatically switching on and off the current between the plurality of power storage modules and the plurality of rectifier units according to the AC power respectively input to the plurality of rectifier units, The plurality of current cut-off parts respectively include: a switch unit connected between the power storage module and the rectifying unit and including at least one switching element; and a driving unit connected between an AC input terminal of the rectifying unit and a control terminal of the switching unit, and generating a control signal for switching the switching unit on and off according to the AC power input to the AC input terminal, The driving unit comprises: A capacitor connected to the AC input terminal; a rectifier circuit connected to the capacitor; and A discharge resistor is connected between the rectifying circuit and the switching unit.

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