Battery charge and discharge test device and battery discharge power control method

Abstract

The present invention provides a battery charge and discharge test device. By using this battery charge and discharge test device, the discharge power generated as regenerative power during the discharge operation of the battery under test can be effectively utilized. The battery charge and discharge test device has a sub charge and discharge unit, which is connected to the main charge and discharge unit through a bus. When the output voltage of the built-in battery of the sub charge and discharge unit is within the power supply voltage range, it performs sub power supply control, which controls the conduction and cutoff of the switching elements of the full-bridge circuit of the sub DC / DC conversion unit through a duty ratio, so as to supply the discharge power of the built-in battery to the bus through the full-bridge circuit, making the voltage between the buses the first specified voltage value. In the sub power supply control, when the voltage between the buses exceeds the first specified voltage value, the sub power supply control is stopped, and constant current charging control is performed, which controls the conduction and cutoff of the above switching elements through a duty ratio, uses the discharge power of the battery under test between the buses as the power supply, and charges the built-in battery through the full-bridge circuit.

Description

Technical Field

[0001] The present invention relates to a battery charge / discharge test device for controlling charge / discharge of a battery in battery characteristic testing and a battery discharge power control method. Background Art

[0002] A battery charge / discharge test device is a device that measures charge / discharge characteristics of a battery under test by performing a charge operation and a discharge operation separately. During each of the charge operation and the discharge operation, for example, the voltage and charge / discharge current of the battery under test are measured over time to obtain the charge / discharge characteristics of the battery under test.

[0003] As a battery charge / discharge test device, there is a device using a bidirectional DC-DC converter as disclosed in Patent Document 1. The bidirectional DC-DC converter is composed of a full-bridge circuit bridging four switching elements. One terminal of the bidirectional DC-DC converter is connected to a DC power supply, and the other terminal is connected to a battery via an inductor. The conduction and cutoff of each switching element of the bidirectional DC-DC converter are controlled by a control unit at a prescribed cycle with a duty ratio. During the charge operation, a charging current is supplied from the DC power supply to the battery via the full-bridge circuit and the inductor of the bidirectional DC-DC converter to charge the battery under test. During the discharge operation, when power regeneration is handled by a self-regeneration method, a discharge current is supplied from the battery to the DC power supply side circuit via the inductor and the full-bridge circuit of the bidirectional DC-DC converter, and the discharge power is consumed in the DC power supply side circuit.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015-122943 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, recently, there has been a demand for a large current specification for battery charge / discharge test devices. When attempting to handle it by a self-regeneration method, cable losses and discharge power that cannot be exhausted by the control power supply and the cooling fan are forcibly consumed in the discharge circuit, resulting in a waste of power consumption.

[0009] Therefore, an object of the present invention is to provide a battery charge / discharge test device and a battery discharge power control method that can effectively utilize the discharge power generated as regenerative power during the discharge operation of the battery under test.

[0010] Means for Solving the Problems

[0011] The battery charge and discharge test device of the present invention includes: a DC power supply unit that outputs a constant voltage DC voltage between two buses; a main DC / DC conversion unit that includes a first full-bridge circuit composed of a plurality of switching elements and having two first input terminals and two first output terminals, the two buses are respectively connected to the two first input terminals, and the positive and negative terminals of the battery under test are respectively connected to the two first output terminals; a main charge and discharge control unit that performs duty cycle control on the conduction and cutoff of each of the plurality of switching elements of the first full-bridge circuit at a first period. In the charge test mode, a charging current is supplied to the battery under test via the first full-bridge circuit to charge the battery under test. In the discharge test mode, the stored charge of the battery under test is discharged via the first full-bridge circuit to supply the discharge power of the battery under test between the two buses; a sub-DC / DC conversion unit that has a second full-bridge circuit composed of a plurality of switching elements and having two second input terminals and two second output terminals, the two buses are respectively connected to the two second input terminals, and the positive and negative terminals of the built-in battery are respectively connected to the two second output terminals; and a sub charge and discharge control unit that performs duty cycle control on the conduction and cutoff of each of the plurality of switching elements of the second full-bridge circuit at a second period to charge and discharge the built-in battery. It is characterized in that when the output voltage of the built-in battery is within the power supply voltage range, the sub charge and discharge control unit executes sub-power supply control. The sub-power supply control supplies the discharge power of the built-in battery between the two buses via the second full-bridge circuit through the duty cycle control of the second period, so that the voltage between the buses is a first specified voltage value, and the first specified voltage value is higher than the constant voltage value of the DC voltage. During the execution of the sub-power control, when the voltage between the buses is lower than the constant voltage value of the DC voltage, the sub-power supply control is stopped; during the execution of the sub-power supply control, when the voltage between the buses exceeds the first specified voltage value, the sub-power supply control is stopped and constant current charging control is executed. The constant current charging control supplies the discharge power of the battery under test between the two buses as a power source through the duty cycle control of the second period, and charges the built-in battery via the second full-bridge circuit. During the execution of the constant current charging control, when the voltage between the buses drops below a second specified voltage value, the constant current charging control is stopped, and the second specified voltage value is higher than the constant voltage value of the DC voltage and lower than the first specified voltage value.

[0012] The battery discharge power control method of the present invention includes: a DC power supply unit that outputs a constant-voltage DC voltage between two buses; a main DC / DC conversion unit that includes a first full-bridge circuit composed of a plurality of switching elements and having two first input terminals and two first output terminals, the two buses being respectively connected to the two first input terminals, and the positive and negative terminals of the battery under test being respectively connected to the two first output terminals; a main charge and discharge control unit that performs duty ratio control on the conduction and cutoff of each of the plurality of switching elements of the first full-bridge circuit at a first period, and in the charging test mode, supplies a charging current to the battery under test via the first full-bridge circuit to charge the battery under test, and in the discharge test mode, discharges the stored charge of the battery under test via the first full-bridge circuit to supply the discharge power of the battery under test between the two buses; a sub-DC / DC conversion unit that has a second full-bridge circuit composed of a plurality of switching elements and having two second input terminals and two second output terminals, the two buses being respectively connected to the two second input terminals, and the positive and negative terminals of the built-in battery being respectively connected to the two second output terminals; a sub charge and discharge control unit that performs duty ratio control on the conduction and cutoff of each of the plurality of switching elements of the second full-bridge circuit at a second period to charge and discharge the built-in battery; and is characterized by including the following steps: when the output voltage of the built-in battery is within the power supply voltage range, the sub charge and discharge control unit executes sub-power supply control, and the sub-power supply control supplies the discharge power of the built-in battery between the two buses via the second full-bridge circuit through duty ratio control of the second period, so that the voltage between the buses is a first specified voltage value, the first specified voltage value being higher than the constant voltage value of the DC voltage, and during the execution of the sub-power control, when the voltage between the buses is lower than the constant voltage value of the DC voltage, the sub-power supply control is stopped; and during the execution of the sub-power supply control, when the voltage between the buses exceeds the first specified voltage value, the sub-power supply control is stopped and constant-current charging control is executed, and the constant-current charging control supplies the discharge power of the battery under test between the two buses as a power source and charges the built-in battery via the second full-bridge circuit through duty ratio control of the second period, and during the execution of the constant-current charging control, when the voltage between the buses drops below a second specified voltage value, the constant-current charging control is stopped, the second specified voltage value being higher than the constant voltage value of the DC voltage and lower than the first specified voltage value.

[0013] Advantages of the Invention

[0014] According to the battery charge and discharge test device and the battery discharge power control method of the present invention, the discharge power obtained from the main DC / DC conversion unit during the discharge test mode is stored in the built-in battery, and the stored power of the built-in battery is supplied to the main DC / DC conversion unit as the charging power source during the charging test mode, so that the discharge power can be effectively utilized.

[0015] Brief Description of the Drawings

[0016] Figure 1 It is a circuit structure diagram showing the application of the battery charge and discharge test device of the present invention.

[0017] Figure 2 It shows Figure 1 The circuit diagram of the structure of the main DC / DC conversion unit in the battery charge and discharge test device.

[0018] Figure 3 It shows Figure 1 The circuit diagram of the structure of the sub DC / DC conversion unit in the battery charge and discharge test device.

[0019] Figure 4 It shows Figure 2 The timing diagram of the on / off state of the switching element in the main DC / DC conversion unit.

[0020] Figure 5 It shows Figure 4 The charging current path diagram in the main DC / DC conversion unit during the charging current period TM1.

[0021] Figure 6 It shows Figure 4 The commutation current path diagram in the main DC / DC conversion unit during the commutation current period TM2.

[0022] Figure 7 It shows Figure 4 The discharge current path diagram in the main DC / DC conversion unit during the discharge current period TM3.

[0023] Figure 8 It shows Figure 4 The commutation current path diagram in the main DC / DC conversion unit during the commutation current period TM4.

[0024] Figure 9 It shows Figure 1 The flowchart of the control action of the sub control unit in the battery charge and discharge test device.

[0025] Figure 10 It is a timing diagram showing the conduction time points of the sub switch and the main switch at the start of the control by the sub control unit, and the start time points of the on / off actions of the switching elements in the sub DC / DC conversion unit.

[0026] Figure 11 It represents Figure 2 a timing diagram showing the on / off states of the switching elements in the sub DC / DC conversion section.

[0027] Figure 12 It represents Figure 11 a charging current path diagram in the sub DC / DC conversion section during the charging current period TS1.

[0028] Figure 13 It represents Figure 11 a commutation current path diagram in the sub DC / DC conversion section during the commutation current period TS2.

[0029] Figure 14 It represents Figure 11 a discharge current path diagram in the sub DC / DC conversion section during the discharge current period TS3.

[0030] Figure 15 It represents Figure 11 a commutation current path diagram in the sub DC / DC conversion section during the commutation current period TS4.

[0031] Figure 16 It represents Figure 9 a flowchart of the gate control of the DC / DC conversion section in the control operation of the sub control section.

[0032] Figure 17 It represents Figure 16 a subsequent part flowchart of the gate control.

[0033] Figure 18 It represents Figure 9 a flowchart of the discharge circuit control in the control operation of the sub control section.

[0034] Figure 19 It represents a voltage range diagram of the bus voltage for separately performing constant current charging control and sub power supply control in the gate control.

[0035] Figure 20 It represents Figure 1 an example structural diagram of using an N-channel FET as a reverse current prevention element in the battery charge / discharge test device. Detailed implementation mode

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] Figure 1Indicates the battery charge and discharge test device of the present invention. This battery charge and discharge test device includes a main charge and discharge unit 11 and a sub charge and discharge unit 12. The main charge and discharge unit 11 is the part that receives the supply of an AC power supply 14 as a primary power source and conducts charge and discharge tests on the battery under test 15. The sub charge and discharge unit 12 has a built-in battery 16 and is the part that receives the discharge power of the battery 15 as a power source and conducts charge and discharge on the built-in battery 16. The rated voltage of the battery under test 15 is, for example, 6 [V], and it can also be lower than the output voltage of the AC / DC conversion unit 21. In this embodiment, the rated voltage of the built-in battery 16 is 12 [V], and the actual output voltage VBAT of the built-in battery 16 varies according to the state of charge of the built-in battery 16.

[0038] The main charge and discharge unit 11 includes an AC / DC conversion unit 21, a diode 22, a main DC / DC conversion unit 23, a main switch 25, a sub switch 26, a resistor 27, a fuse 28, voltage detection units 29, 30, and a main control unit 50.

[0039] The AC / DC conversion unit 21 constitutes a DC power supply unit and is connected to the AC power supply 14. When the AC voltage output by the AC power supply 14 is input to the input terminals 21A and 21B, the AC / DC conversion unit 21 converts the AC voltage into a specified DC voltage through rectification and outputs the DC voltage from the output terminals 21C and 21D. In this embodiment, it is described with a constant voltage of 200 [V] for the AC voltage output by the AC power supply 14 and 24.0 [V] for the DC voltage output by the AC / DC conversion unit 21.

[0040] The anode of the diode 22 is connected to the positive voltage side output terminal of the AC / DC conversion unit 21. The cathode of the diode 22 is connected to the terminal 23A of the main DC / DC conversion unit 23 via the bus L1. The negative voltage side output terminal 21D of the AC / DC conversion unit 21 is connected to the terminal 23B of the main DC / DC conversion unit 23 via the bus L2. The diode 22 is used to make the current flow unidirectionally only from the anode to the cathode. Specifically, the diode 22 makes the charging current flow from the AC / DC conversion unit 21 to the main DC / DC conversion unit 23 and blocks the discharge current from flowing from the main DC / DC conversion unit 23 to the AC / DC conversion unit 21. In addition, the diode 22 also blocks the discharge current from flowing into the AC / DC conversion unit 21 from the sub DC / DC conversion unit 51 described later.

[0041] As Figure 2 shown, the main DC / DC conversion unit 23 includes a full-bridge circuit 35, chokes 36, 37, capacitors 38, 39, and a current detector 40. The full-bridge circuit 35 is composed of four semiconductor switch elements 31 to 34 such as IGBTs (Insulated Gate Bipolar Transistors).

[0042] The main DC / DC conversion unit 23 has four terminals 23A to 23D for external connection. A capacitor 38 is connected between terminals 23A and 23B.

[0043] The full-bridge circuit 35 is the first full-bridge circuit, and the semiconductor switching elements 31 to 34 correspond to the first to fourth switching elements. In the full-bridge circuit 35, one ends (one of the two first input terminals) of the semiconductor switching elements 31 and 33 are connected to terminal 23A, and one ends (the other of the two first input terminals) of the semiconductor switching elements 32 and 34 are connected to 23B. The other ends (one of the two first output terminals) of the semiconductor switching elements 31 and 32 are connected to each other, and the connection point is connected to terminal 23C in series through a choke coil 36 and a current detection unit 40. In addition, the other ends (the other of the two first output terminals) of the semiconductor switching elements 33 and 34 are connected to each other, and the connection point is connected to terminal 23D through a choke coil 37. A capacitor 39 is connected between terminals 23C and 23D. The choke coils 36 and 37 as inductors and the capacitor 39 as a capacitor constitute a first smoothing circuit.

[0044] The semiconductor switching elements 31 to 34 respectively have freewheeling diodes (flywheel diodes) 41 to 44 to prevent damage during conduction. Specifically, the freewheeling diodes 41 to 44 are respectively connected in parallel with the semiconductor switching elements 31 to 34. When using an IGBT as the semiconductor switching element, the cathode of this freewheeling diode is connected to the collector of the IGBT, and the anode of this freewheeling diode is connected to the emitter of the IGBT.

[0045] The full-bridge circuit 35 basically repeats with a period T1 (first period) composed of a charging current period TM1, a commutation current period TM2, a discharging current period TM3, and a commutation current period TM4. During the charging current period TM1, the semiconductor switching elements 31 and 34 are turned on, and the semiconductor switching elements 32 and 33 are turned off. During the commutation current period TM2, the semiconductor switching elements 31 to 34 are turned off, and the freewheeling diodes 42 and 43 are turned on. During the discharging current period TM3, the semiconductor switching elements 31 and 34 are turned off, and the semiconductor switching elements 32 and 33 are turned on. During the commutation current period TM4, the semiconductor switching elements 31 to 34 are turned off, and the freewheeling diodes 41 and 44 are turned on. The conduction and turning off of the semiconductor switching elements 31 to 34 are controlled by the main control unit 50. The duty ratio controls the charging current period TM1 and the discharging current period TM3. In this embodiment, the duty ratio of the main control unit 50 is represented by DM, which is the ratio of the charging current period TM1 to the total period of the charging current period TM1 and the discharging current period TM3. For example, when the main charge and discharge unit 11 is in the charging test mode of the battery 15, the duty ratio DM is greater than 50%, that is, the charging current period TM1 is longer than the discharging current period TM3 within one period T1, and the battery 15 is charged by the charging current flowing into the battery 15. When the main charge and discharge unit 11 is in the discharging test mode of the battery 15, the duty ratio DM is less than 50%, that is, the charging current period TM1 is shorter than the discharging current period TM3 within one period T1, and the battery 15 is discharged by the discharging current.

[0046] The terminal 23C of the main DC / DC conversion unit 23 is connected in series via the main switch 25 to the positive terminal of the battery 15. A series circuit of the sub-switch 26 and the resistor 27 is connected in parallel with the main switch 25. The terminal 23D of the main DC / DC conversion unit 23 is connected to the negative terminal of the battery 15 via the fuse 28. At the start of the charge and discharge test, for example, when the charging voltage of the battery 15 is below a predetermined first threshold voltage, when supplying a charging current to the battery 15, the sub-switch 26 is first turned on, and then after a predetermined period of time, the main switch 25 is turned on. This is to prevent the battery 15 from supplying an excessive charging current to the capacitor 39 of the main DC / DC conversion unit 23 due to the voltage difference between the capacitor 39 of the main DC / DC conversion unit 23 and the voltage of the battery 15 at the start of the charge and discharge test.

[0047] The current detection unit 40 detects the value of the current flowing between the full-bridge circuit 35 and the battery 15. That is, in the charging test mode, it detects the charging current value for charging the battery 15, and in the discharging test mode, it detects the discharging current value when the battery 15 discharges. The current detection unit 40 is constituted by, for example, a resistor or a current sensor. The voltage detection unit 29 detects the voltage between the output terminals 21C and 21D of the AC / DC conversion unit 21 and the voltage VDC between the terminals 23A and 23B of the main DC / DC conversion unit 23. The voltage VDC is the bus voltage between the buses L1 and L2. The voltage detection unit 30 detects the voltage between the positive and negative terminals of the battery 15.

[0048] The main control unit 50 is constituted by, for example, a microcomputer. The detection outputs of the current detection unit 40 and the voltage detection units 29 and 30 are connected to the main control unit 50, and the current value detected by the current detection unit 40 and the voltage values detected by the voltage detection units 29 and 30 respectively are supplied to the main control unit 50. The main control unit 50 is connected to the main DC / DC conversion unit 23 and controls the conduction and cutoff of the semiconductor switch elements 31 to 34 in the main DC / DC conversion unit 23. The main control unit 50 is connected to the control terminals of the main switch 25 and the sub-switch 26 and controls the conduction and cutoff of the main switch 25 and the sub-switch 26 respectively.

[0049] In addition, the test PC (personal computer) 47 is connected to the main control unit 50 via the charge and discharge controller 46. During the charge and discharge test of the battery 15, various operation commands are provided from the test PC 47 to the main control unit 50 via the charge and discharge controller 46 according to the operation of the test PC 47.

[0050] In addition to the above-mentioned built-in battery 16, the sub charge and discharge unit 12 further includes a sub DC / DC conversion unit 51, a voltage detection unit 52, a fuse 53, a main switch 55, a resistor 56, a sub-switch 57, and a simple discharge circuit 58, a fuse 59, a temperature sensor 60, a voltage detection unit 61, and a sub control unit 62.

[0051] As Figure 3 shown, the sub DC / DC conversion unit 51 has the same structure as the main DC / DC conversion unit 23 and includes a full-bridge circuit 75, choke coils 76, 77, capacitors 78, 79, and a current detector 80. The full-bridge circuit 75 is constituted by semiconductor switch elements 71 to 74 such as 4 IGBTs (insulated gate bipolar transistors).

[0052] The sub DC / DC conversion unit 51 has four terminals 51A to 51D for external connection. The capacitor 78 is connected between the terminals 51A and 51B.

[0053] The full-bridge circuit 75 is the second full-bridge circuit, and the semiconductor switching elements 71 to 74 correspond to the fifth to eighth switching elements. In the full-bridge circuit 75, one ends of the semiconductor switching elements 71 and 73 (one of the two second input terminals) are connected to the terminal 51A, and one ends of the semiconductor switching elements 72 and 74 (the other of the two second input terminals) are connected to the terminal 51B. The other ends of the semiconductor switching elements 71 and 72 (one of the two second output terminals) are connected to each other, and this connection point is connected to the terminal 51C in series through the choke coil 76 and the current detection unit 80. In addition, the other ends of the semiconductor switching elements 73 and 74 (the other of the two second output terminals) are connected to each other, and this connection point is connected to the terminal 51D through the choke coil 77. The capacitor 79 is connected between the terminals 51C and 51D. The choke coils 76 and 77 and the capacitor 79 constitute the second smoothing circuit.

[0054] Similar to the semiconductor switching elements 31 to 34, the semiconductor switching elements 71 to 74 respectively have freewheeling diodes 81 to 84 to prevent damage during conduction.

[0055] The full-bridge circuit 75 basically repeats with the charging current period TS1, the commutation current period TS2, the discharging current period TS3, and the commutation current period TS4 as one cycle T2 (the second cycle). During the charging current period TS1, the semiconductor switching elements 71 and 74 are turned on, and the semiconductor switching elements 72 and 73 are turned off. During the commutation current period TS2, the semiconductor switching elements 71 to 74 are turned off, and the freewheeling diodes 82 and 83 are turned on. During the discharging current period TS3, the semiconductor switching elements 71 and 74 are turned off, and the semiconductor switching elements 72 and 73 are turned on. During the commutation current period TS4, the semiconductor switching elements 71 to 74 are turned off, and the freewheeling diodes 81 and 84 are turned on. The on / off of the semiconductor switching elements 71 to 74 is controlled by the sub-control unit 62. In addition, the duty ratio controls the charging current period TS1 and the discharging current period TS3 within one cycle T2. The duty ratio of this sub-control unit 62 is represented by DS hereinafter, and is the ratio of the charging current period TS1 to the total period of the charging current period TS1 and the discharging current period TS3. When the sub-charge / discharge unit 12 is in the charging mode, the duty ratio DS is greater than 50%, that is, the charging current period TS1 within one cycle T2 is longer than the discharging current period TS3, and the built-in battery 16 is charged by the charging current flowing into the built-in battery 16. When the sub-charge / discharge unit 12 is in the discharging mode, the duty ratio DS is less than 50%, that is, the charging current period TS1 within one cycle T2 is shorter than the discharging current period TS3, and the built-in battery 16 is discharged by the discharging current of the built-in battery 16.

[0056] The terminal 51C of the sub-DC / DC conversion unit 51 is connected to the positive terminal of the built-in battery 16 via the main switch 55. A series circuit of the resistor 56 and the sub-switch 57 is connected in parallel with the main switch 55. The main switch 55 and the sub-switch 57 are composed of relay switches. The resistor 56 and the sub-switch 57 are provided to prevent an excessive charging current from flowing from the built-in battery 16 to the capacitor 79 of the sub-DC / DC conversion unit 51 due to the voltage difference between the capacitor 79 of the sub-DC / DC conversion unit 51 and the voltage of the built-in battery 16, and also to pre-charge the capacitor 79 immediately after power-on.

[0057] The terminal 51D of the sub-DC / DC conversion unit 51 is connected to the negative terminal of the built-in battery 16 via the fuse 59. The current detection unit 80 detects the level of the current Isub flowing between the full-bridge circuit 75 of the sub-DC / DC conversion unit 51 and the built-in battery 16. The current detection unit 80 may also be configured using a resistor or a current sensor, for example.

[0058] The simple discharge circuit 58 is connected between the positive terminal of the built-in battery 16 and the bus where the terminal 51D is connected to the fuse 59. As an example of the simple discharge circuit 58, a series circuit of a discharge switch 64 composed of a relay switch and a resistor 65 is described. The discharge switch 64 may also use a semiconductor switch such as an FET. When the discharge switch 64 is turned on, the resistor 65 forms a circuit between the two terminals of the built-in battery 16, and the stored charge of the built-in battery 16 is discharged.

[0059] The temperature sensor 60 detects the temperature of the built-in battery 16. The voltage detection unit 61 detects the voltage VBAT between the positive and negative terminals of the built-in battery 16.

[0060] The sub-control unit 62 is composed of a microcomputer, for example. The detection outputs of the voltage detection units 52 and 61, the current detection unit 80, and the temperature sensor 60 are connected to the sub-control unit 62. The voltage values detected by the voltage detection units 52 and 61, the current value detected by the current detection unit 80, and the temperature value detected by the temperature sensor 60 are supplied to the sub-control unit 62. The sub-control unit 62 is connected to the sub-DC / DC conversion unit 51, and controls the conduction and cutoff of the semiconductor switch elements 71 to 74 in the full-bridge circuit 75 in the sub-DC / DC conversion unit 51 based on the voltage values detected by the voltage detection units 52 and 61, the current value detected by the current detection unit 80, and the temperature value detected by the temperature sensor 60. In addition, the sub-control unit 62 is connected to the control terminals of the main switch 55, the sub-switch 57, and the discharge switch 64, and controls the conduction and cutoff of the main switch 55, the sub-switch 57, and the discharge switch 64 respectively.

[0061] In addition, the sub-control unit 62 and the main control unit 50 are connected via buses L1 and L2. When an error occurs during the operation of the sub-control unit 62, the sub-control unit 62 provides an error occurrence signal to the main control unit 50.

[0062] The DC power supplies for the control operations of the main control unit 50 and the sub-control unit 62 can use the output power of the AC / DC conversion unit 21, or an additional power supply can be prepared.

[0063] Next, the operation of the battery charge / discharge test device of the present invention having this configuration will be described.

[0064] In the main charge / discharge unit 11, when the AC voltage output by the AC power supply 14 is supplied to the AC / DC conversion unit 21, the AC / DC conversion unit 21 outputs a 24 [V] DC voltage. The 24 [V] DC voltage output by the AC / DC conversion unit 21 is supplied between the terminals 23A and 23B of the main AC / DC conversion unit 23 via the diode 22. A positive potential of 24.0 [V] is applied to the terminal 23A, and a potential of 0 [V] is applied to the terminal 23B.

[0065] It should be noted that the voltage supplied from the AC / DC conversion unit 21 to between the terminals 23A and 23B of the main DC / DC conversion unit 23 via the diode 22 is accurately the voltage obtained by reducing the forward voltage drop of the diode 22 from the 24 [V] DC voltage, but here it is described as the 24 [V] DC voltage.

[0066] The main control unit 50 determines the duty ratio DM based on, for example, the current values of the charging current or discharging current obtained from the current detection unit 40 and the voltage values obtained from the voltage detection units 29 and 30 in each cycle T1, so that, for example, the voltage of the battery 15 becomes a desired voltage value, or the charging current and the discharging current respectively become desired current values, and provides a control signal representing the duty ratio DM to the main DC / DC conversion unit 23.

[0067] In a state where a 24 [V] DC voltage is applied between the terminals 23A and 23B of the main DC / DC conversion unit 23, when control signals for the semiconductor switching elements 31 to 34 are provided from the main control unit 50 to the main DC / DC conversion unit 23, the semiconductor switching elements 31 to 34 start the conduction and cutoff operations.

[0068] As Figure 4As shown, in the main DC / DC conversion unit 23, the on / off control of the semiconductor switching elements 31 to 34 is repeated in a cycle T1 with a charging current period TM1, a commutation current period TM2, a discharging current period TM3, and a commutation current period TM4. During the charging current period TM1, the semiconductor switching elements 31 and 34 are turned on, and the semiconductor switching elements 32 and 33 are turned off. During the discharging current period TM3, the semiconductor switching elements 31 and 34 are turned off, and the semiconductor switching elements 32 and 33 are turned on. During the commutation current period TM2 immediately after the charging current period TM1 ends, all of the semiconductor switching elements 31 to 34 are turned off. Similarly, during the commutation current period TM4 immediately after the discharging current period TM3 ends, all of the semiconductor switching elements 31 to 34 are turned off. In the control when the duty ratio DM is 50%, the lengths of the charging current period TM1 and the discharging current period TM3 are equal and are {T1 - (TM2 + TM4)} / 2.

[0069] As Figure 5 shown by the arrow MA in [FIGURE], during the charging current period TM1, the charging current flows from the positive terminal of the battery 15 through the terminal 23A, the semiconductor switching element 31, the choke coil 36, the current detection unit 40, the terminal 23C, and the main switch 25 in sequence, and then flows into the battery 15. Next, it flows through the fuse 28, the terminal 23D, the choke coil 37, the semiconductor switching element 34, and the terminal 23B in sequence from the negative terminal of the battery 15. The battery 15 is charged by the flow of this charging current, and charges are accumulated in the battery 15.

[0070] As Figure 6 shown by the arrow MB in [FIGURE], during the commutation current period TM2, the energy accumulated in the choke coils 36 and 37 during the charging current period TM1 causes the commutation current to flow in the direction of the charging current. During this commutation current period TM2, the freewheeling diodes 42 and 43 are turned on, and the commutation current flows along the path of the terminal 23B, the freewheeling diode 42, the choke coil 36, the current detection unit 40, the terminal 23C, the main switch 25, the battery 15, the fuse 28, the terminal 23D, the choke coil 37, the freewheeling diode 43, and the terminal 23A to charge the battery 15.

[0071] As Figure 7 shown by the arrow MC in [FIGURE], during the discharging current period TM3, the discharging current flows to the terminal 23A, the semiconductor switching element 33, the choke coil 37, the terminal 23D, the fuse 28, and the negative terminal of the battery 15, and further from the positive terminal of the battery 15 through the main switch 25, the terminal 23C, the current detection unit 40, the choke coil 36, and the semiconductor switching element 32 in sequence to reach the terminal 23B. This discharging current is the current that discharges the stored charges of the battery 15.

[0072] As Figure 8As shown by the arrow MD, during the commutation current period TM4, the energy accumulated in the chokes 36 and 37 during the discharge current period TM3 causes the commutation current to flow in the direction of the discharge current. During the commutation current period TM4, the freewheeling diodes 41 and 44 are turned on, and the commutation current flows along the path of terminal 23B, freewheeling diode 44, choke 37, terminal 23D, fuse 28, battery 15, main switch 25, terminal 23C, current detection unit 40, choke 36, freewheeling diode 41, and terminal 23A. The discharge power generated by commutation is obtained between the output terminals 23A and 23B and is used as regenerative power. A regenerative voltage is generated between the output terminals 23A and 23B, which is the sum of the terminal voltage of choke 36, the terminal voltage of battery 15, and the terminal voltage of choke 37. This regenerative voltage decreases as the terminal voltage (output voltage) of battery 15 decreases due to the discharge of battery 15 and as the energy of chokes 36 and 37 is released.

[0073] It should be noted that since the diode 22 is provided on the line L1 connected to the terminal 23A, even if the DC voltage between the lines L1 and L2 becomes higher than the 24 [V] DC voltage output by the AC / DC conversion unit 21 due to the regenerative voltage, the current flowing into the AC / DC conversion unit 21 via the line L1 will be blocked.

[0074] According to the ratio of the charging current period TM1 and the discharge current period TM3 within one cycle T1, that is, the duty ratio DM, the operation of one cycle T1 is determined to be the charging test mode or the opposite discharge test mode. In the duty ratio DM control of the charging test mode, the charging current period TM1 increases within one cycle T1, while the discharge current period TM3 decreases. Therefore, the amount of charge of the charging current during the charging current period TM1 to charge the battery 15 exceeds the amount of charge discharged from the battery 15 by the discharge current during the discharge current period TM3. As a result, the battery 15 is charged within one cycle T1.

[0075] Conversely, in the duty ratio DM control of the discharge test mode, the charging current period TM1 decreases within one cycle T1, while the discharge current period TM3 increases. Therefore, the amount of charge discharged from the battery 15 by the discharge current during the discharge current period TM3 exceeds the amount of charge of the charging current during the charging current period TM1 to charge the battery 15. As a result, the battery 15 is discharged within one cycle T1.

[0076] In the charging test mode, for example, the duty ratio DM controls the current value detected by the current detection unit 40 to be a predetermined charging current value until the voltage value of the battery 15 detected by the voltage detection unit 30 rises to the set voltage value V1. In the discharging test mode, for example, the duty ratio DM controls the current value detected by the current detection unit 40 to be a predetermined discharging current value until the voltage value of the battery 15 detected by the voltage detection unit 30 drops to the set voltage value V2 (V2 < V1).

[0077] The charging charge amount during the charging current period TM1 within the period T1 is equal to the discharging charge amount during the discharging current period TM3, and its duty ratio DM is, for example, 50%. Since the charging current and the discharging current within one period T1 cancel each other out, the average current is 0. As a result, the charge amount of the battery 15 does not change.

[0078] On the other hand, in the sub charge-discharge unit 12, the regenerative power (discharging power) generated by the main control unit 50 in the discharging test mode is used as a power source to charge the built-in battery 16. At the same time, the charge accumulated in the built-in battery 16 by this charging is utilized as a part of the DC power source in the charging test mode of the main control unit 50.

[0079] As Figure 9 shown, when the AC power supply 14 is turned on, the sub control unit 62 determines whether an ALM (alarm) has occurred (step S11). The ALM includes upper and lower limit abnormalities of the temperature of the built-in battery 16 detected by the temperature sensor 60, upper and lower limit abnormalities of the output voltage VBAT of the built-in battery 16 detected by the voltage detection unit 61, upper and lower limit abnormalities of the charge-discharge current ISUB detected by the current detection unit 80, and upper and lower limit abnormalities of the bus voltage VDC detected by the voltage detection unit 52. If such an ALM occurs, the sub control unit 62 controls the main switch 55 and the sub switch 57 of the sub charge-discharge unit 12 to turn off together (step S12). On the other hand, if no ALM is notified, the sub switch 57 is controlled to conduct (step S13), and a timer (not shown in the figure) measures whether a certain time Tpchg has elapsed since this time point (step S14).

[0080] As Figure 10 shown, if the sub switch 57 conducts at the time point t1, a path is formed from the positive terminal of the built-in battery 16 to the sub switch 57, the resistor 56, the terminal 51C, the capacitor 79, the terminal 51D, the fuse 59, and the negative terminal of the built-in battery 16. Current flows from the built-in battery 16 through this path to charge the capacitor 79, that is, to perform pre-charging on it. During this pre-charging period, the current flowing through the capacitor 79 within a certain time Tpchg is limited by the resistor 56.

[0081] If a certain time Tpchg has elapsed, the sub-control unit 62 controls the main switch 55 of the sub charge / discharge unit 12 to conduct (step S15). Thereby, the sub DC / DC conversion unit 51 and the built-in battery 16 are in a state of being electrically connected via the main switch 55, and the sub-control unit 62 executes a subroutine, which consists of the gate control (step S16) of the sub DC / DC conversion unit 51 and the discharge circuit control (step 17).

[0082] After performing the gate control of the sub DC / DC conversion unit 51 in step 16 and the discharge circuit control in step 17, the sub-control unit 62 determines whether an ALM has occurred (step S18). If no ALM has occurred, the sub-control unit 62 executes the sub DC / DC gate control in step 16 and the discharge circuit control in step 17 again. If an ALM has occurred, it proceeds to step S12 to control the main switch 55 and the sub-switch 57 of the sub charge / discharge unit 12 to turn off together.

[0083] As Figure 10 shown, after a certain time Tpchg has elapsed from time point t1, at time point t2, the main switch 55 is controlled to turn from off to on. Then, after another time Tonstart, at time point t3, through the operation of the sub DC / DC gate control in step S16, gate signals are provided from the sub-control unit 62 to the semiconductor switch elements 71 to 74 of the full-bridge circuit 75, and the conduction and turn-off of the semiconductor switch elements 71 to 74 are started.

[0084] As Figure 11 shown, in the sub DC / DC conversion unit 51, the conduction and turn-off control of the semiconductor switch elements 71 to 74 is repeated in a cycle T2 with a charging current period TS1, a commutation current period TS2, a discharging current period TS3, and a commutation current period TS4. In the charging current period TS1, the semiconductor switch elements 71 and 74 are conducting, and the semiconductor switch elements 72 and 73 are off. In the discharging current period TS3, the semiconductor switch elements 71 and 74 are off, and the semiconductor switch elements 72 and 73 are conducting. In the commutation current period TS2 immediately after the charging current period TS1 ends, all of the semiconductor switch elements 71 to 74 are off. Similarly, in the commutation current period TS4 immediately after the discharging current period TS3 ends, all of the semiconductor switch elements 71 to 74 are off. In the control with a duty ratio DS of 50%, the lengths of the charging current period TS1 and the discharging current period TS3 are equal, and are {T2 - (TS2 + TS4)} / 2.

[0085] As Figure 12As shown by arrow SA in the figure, during the charging current period TS1, the charging current flows from the positive terminal of the built-in battery 16, sequentially through terminal 51A, semiconductor switch element 71, choke coil 76, current detection section 80, terminal 51C, and main switch 55, and then flows into the built-in battery 16. Next, it flows from the negative terminal of the built-in battery 16, sequentially through fuse 59, terminal 51D, choke coil 77, semiconductor switch element 74, and terminal 51B. By the flow of this charging current, the built-in battery 16 is charged, and charges are accumulated in the built-in battery 16.

[0086] As Figure 13 As shown by arrow SB in the figure, during the commutation current period TS2, the energy stored in choke coils 76 and 77 during the charging current period TS1 causes the commutation current to flow in the direction of the charging current. During this commutation current period TS2, freewheeling diodes 82 and 83 are turned on, and the commutation current flows along the path of terminal 51B, freewheeling diode 82, choke coil 76, current detection section 80, terminal 51C, main switch 55, built-in battery 16, fuse 59, terminal 51D, choke coil 77, freewheeling diode 83, and terminal 51A. This commutation current decreases as the energy of choke coils 76 and 77 is released.

[0087] As Figure 14 As shown by arrow SC in the figure, during the discharge current period TS3, the discharge current flows to terminal 51A, semiconductor switch element 73, choke coil 77, terminal 51D, fuse 59, and the negative terminal of the built-in battery 16. Further, it sequentially passes through the main switch 55, terminal 51C, current detection section 80, choke coil 76, and semiconductor switch element 72 from the positive terminal of the built-in battery 16 and reaches terminal 51B. This discharge current is the current that discharges the stored charges in the built-in battery 16.

[0088] As Figure 15 As shown by arrow SD in the figure, during the commutation current period TS4, the energy stored in choke coils 76 and 77 during the discharge current period TS3 causes the commutation current to flow in the direction of the discharge current. During the commutation current period TS4, freewheeling diodes 81 and 84 are turned on, and the commutation current flows along the path of terminal 51B, freewheeling diode 84, choke coil 77, terminal 51D, fuse 59, built-in battery 16, main switch 55, terminal 51C, current detection section 80, choke coil 76, freewheeling diode 81, and terminal 51A. The discharge power generated by commutation is obtained between output terminals 51A and 51B as regenerative power. A regenerative voltage is generated between output terminals 51A and 51B, which is the sum of the terminal voltage of choke coil 76, the terminal voltage of the built-in battery 16, and the terminal voltage of choke coil 77. This regenerative voltage decreases as the energy of choke coils 76 and 77 is released.

[0089] Similar to the main DC / DC conversion unit 23, in the sub DC / DC conversion unit 51, based on the ratio of the charging current period TS1 and the discharging current period TS3 within one cycle T2, that is, the duty ratio DS, it is determined whether the operation in one cycle T2 is in the charging test mode or the opposite discharging test mode. In the duty ratio DS control of the charging test mode, the amount of charge that the charging current during the charging current period TS1 within one cycle T2 charges the built-in battery 16 exceeds the amount of charge that the discharging current during the discharging current period TS3 discharges from the built-in battery 16. On the contrary, in the case of the duty ratio DS of the discharging mode, the amount of charge discharged from the built-in battery 16 exceeds the amount of charge charged. When the amount of charge charged during the charging current period TS1 within the cycle T2 is equal to the amount of charge discharged during the discharging current period TS3, and its duty ratio DS is, for example, 50%, since the charging current and the discharging current within the cycle T2 cancel each other out, the average current is 0. As a result, the amount of charge of the built-in battery 16 does not change. Which of the charging mode and the discharging mode is set as the operation mode in the sub DC / DC gate control of the above step S16.

[0090] Next, the details of the gate control of the sub DC / DC conversion unit 51 in step S16 will be described.

[0091] As Figure 16 and 17 shown, in the gate control of step S16, the sub-control unit 62 first determines whether the bus voltage VDC obtained from the voltage detection unit 52 is lower than 21.6 [V] (step S21). If VDC ≥ 21.6 [V], then it is determined whether the bus voltage VDC is higher than 25.0 [V] (step S22).

[0092] As described above, the bus voltage VDC is the voltage between the terminals 23A and 23B of the main DC / DC conversion unit 23, and is also the voltage between the terminals 51A and 51B of the sub DC / DC conversion unit 51. If regenerative power is generated in the main DC / DC conversion unit 23, then the bus voltage VDC will rise above the 24 [V] DC voltage supplied from the AC / DC conversion unit 21 between the terminals 23A and 23B.

[0093] If 21.6 [V] ≤ VDC ≤ 25.0 [V], the sub-control unit 62 determines whether the output voltage VBAT of the built-in battery 16 is within the power supply voltage range of 9.2 [V] ≤ VBAT ≤ 13.0 [V] (step S23). The output voltage VBAT of the internal battery 16 is detected by the voltage detection unit 61. If 9.2 [V] ≤ VBAT ≤ 13.0 [V], the sub-control unit 62 determines whether the gate signal is in the off state (step S24). If the gate signal is in the off state, the sub-power supply control is started (step S25). The off state of the gate signal means that the semiconductor switching elements 71 to 74 of the sub-DC / DC conversion unit 51 are all controlled to be off. In the sub-power supply control, the sub-DC / DC conversion unit 51 is controlled by the above-mentioned discharge mode duty ratio to make the bus voltage VDC a constant voltage of 24.5 [V]. In the discharge mode control, the regenerative power generated by the commutation operation of the commutation current period TS4 is obtained from the sub-DC / DC conversion unit 51, and this regenerative power is supplied to the main DC / DC conversion unit 23 via the buses L1 and L2. The commutation current period TS4 utilizes the stored energy of the built-in battery 16 and the chokes 76 and 77.

[0094] After the sub-power supply control starts, the sub-control unit 62 determines whether the bus voltage VDC is higher than the first specified voltage value of 24.5 [V] (step S26). If VDC > 24.5 [V], the main charge / discharge unit 11 may be in the discharge test mode, and the main DC / DC conversion unit 23 is outputting regenerative power. Therefore, if VDC > 24.5 [V], the sub-control unit 62 stops the sub-power supply control (step S27), and determines whether the output voltage VBAT of the built-in battery 16 is within the range of 9.0 [V] ≤ VBAT ≤ 12.8 [V] (step S28). If 9.0 [V] ≤ VBAT ≤ 12.8 [V], the sub-control unit 62 starts the constant current charging control of the built-in battery 16 (step S29). In the constant current charging control, the sub-DC / DC conversion unit 51 is controlled by the duty ratio so that the current ISUB becomes the constant current value set in the above charging mode. In the control in the charging mode, the sub-control unit 62 starts the duty ratio control with the regenerative power obtained from the main DC / DC conversion unit 23 as the power supply. The duty ratio DS only increases the predetermined control duration of the charging current period TS1 within the period T2, and the discharge current period TS3 only decreases by the amount of this increase. Through this duty ratio control of the charging mode, the preset constant current Isub in each period T2 flows into the built-in battery 16 to charge the built-in battery 16. The current Isub is the average value of the current flowing into the built-in battery 16 within the period T2, and is the current value detected by the above-mentioned current detection unit 80.

[0095] After performing step S29, the sub-control unit 62 determines whether the bus voltage VDC has decreased due to the consumption of regenerative power from the main DC / DC converter 23 (step S30). In step S30, the bus voltage VDC obtained from the voltage detection unit 52 is observed, and it is determined whether the current value of the bus voltage VDC is lower than the previous value. If the bus voltage VDC has not decreased, the sub-control unit 62 performs an increase control of the current Isub (step S31). In step S31, by increasing the duty ratio DS, the charging current period TS1 within the period T2 is further increased by only a unit time duration, and the discharge current period TS3 is decreased by only this increased amount, thereby increasing the current Isub. The regenerative power from the main DC / DC converter 23 consumes only the increased amount of the current Isub, and as a result, the bus voltage VDC decreases.

[0096] In step S30, if the sub-control unit 62 determines that the bus voltage VDC has dropped, it is determined whether the bus voltage VDC obtained from the voltage detection unit 52 is below the second specified voltage value of 24.4 [V] (step S32). If VDC > 24.4 [V], the sub-control unit 62 performs a decrease control of the current Isub (step S33). In step S33, by decreasing the duty ratio DS, the charging current period TS1 within the period T2 is decreased by only a unit time duration, and the discharge current period TS3 is increased by only this decreased amount, thereby decreasing the current Isub. The consumption of regenerative power can be controlled to consume only the decreased amount of the current Isub.

[0097] In step S32, if the sub-control unit 62 determines that VDC ≤ 24.4 [V], the bus voltage VDC is decreased below 24.4 [V] by constant current charging control, and thereby the constant current charging control is stopped (step S34).

[0098] In addition, in step S26, if the sub-control unit 62 determines that VDC ≤ 24.5 [V], it is determined whether the output voltage VBAT of the built-in battery 16 is lower than 10.0 [V] (step S35). If VBAT < 10.0 [V], it is determined whether the bus voltage VDC is below 24.0 [V] (step S36). If VDC > 24.0 [V], the output set voltage of the main DC / DC converter 23 is decreased by only 0.1 [V] (step S37). That is, in the sub-power supply control, even if VBAT drops below 10.0 [V] due to the discharge of the built-in battery 16, as long as VDC > 24.0 [V], the output set voltage of the main DC / DC converter 23 is decreased by only 0.1 [V], and at the same time, the sub-power supply control is continued. On the other hand, if VDC ≤ 24.0 [V], the sub-power supply control is stopped (step S38).

[0099] When it is determined in step S24 that the gate signal is not in the off state, the sub-control unit 62 determines whether the built-in battery 16 is discharging, that is, whether it is in the discharge mode (step S39). If it is in the discharge mode, sub-power supply control is in progress, so the above step S26 is entered to determine whether the bus voltage VDC is higher than 24.5 [V].

[0100] On the other hand, if it is determined in step S39 that it is not in the discharge mode, the sub-control unit 62 determines whether the built-in battery 16 is charging, that is, whether it is in the charging mode (step S40). If it is in the charging mode, constant current charging control is being performed on the built-in battery 16, so the above step S30 is entered to determine whether the bus voltage VDC is decreasing. If it is determined in step S40 that it is not in the charging mode, the sub-control unit 62 stops generating the gate signal (step S41) and executes error control (step S42). When it is determined in step S21 that VDC < 21.6 [V] (the bus voltage VDC is a low voltage), when it is determined in step S22 that VDC > 25.0 [V] (the bus voltage is an overvoltage), and also when VBAT < 9.0 [V] (the built-in battery 16 is in a low voltage state) or VBAT > 12.8 [V] (the built-in battery 16 is in an overvoltage state) in step S28, steps S41 and S42 are executed.

[0101] By stopping the generation of the gate signal in step S41, the above gate signal is turned into the off state, and the semiconductor switching elements 71 to 74 are controlled to turn off. The error control in step S42 is for handling when an abnormal state is determined in steps S21, S22, S28, or S40.

[0102] As Figure 18 shown, in the discharge circuit control of step S17, the sub-control unit 62 determines whether the output voltage VBAT of the built-in battery 16 is higher than 13.0 [V] (step S51). If VBAT ≤ 13.0 [V], the built-in battery 16 is not in the overcharged state, so there is no need for discharge. Therefore, if VBAT ≤ 13.0 [V], the sub-control unit 62 controls the discharge switch 64 to turn off (step S52). On the other hand, if VBAT > 13.0 [V], the built-in battery 16 is in the overcharged state, so discharge is required. Therefore, if VBAT > 13.0 [V], the sub-control unit 62 determines whether the discharge switch 64 is in the on state (step S53). If the discharge switch 64 is not in the on state, the sub-control unit 62 controls the discharge switch 64 to turn on (step S53). Since the discharge switch 64 is turned on, the discharge current from the built-in battery 16 flows through the resistor 65 and the discharge switch 64, so the output voltage VBAT of the built-in battery 16 is forced to decrease.

[0103] Figure 19Indicates the voltage range of the bus voltage VDC for separately performing constant current charging control and sub-power supply control.

[0104] As described above, when the main charge / discharge unit 11 is in the discharge test mode, the regenerative voltage generated between the terminals 23A and 23B of the main DC / DC conversion unit 23 causes the bus voltage VDC to be higher than the DC voltage 24.0 [V] output by the AC / DC conversion unit 21. When the output voltage VBAT of the built-in battery 16 is within the rechargeable voltage range of 9.0 [V] ≤ VBAT ≤ 12.8 [V] and VDC > 24.5 [V] is satisfied, the constant current charging control starts. After the constant current charging control starts, since the built-in battery 16 is charged, the bus voltage VDC drops, and when it becomes 24.4 [V] or less, the constant current charging control stops. In addition, when the bus voltage VDC is higher than 25.0 [V], it is considered that the battery 15 test is abnormal, and the constant current charging control stops. Therefore, Figure 19 The shown area CC is the execution range of the constant current charging control, that is, the area where the built-in battery 16 is charged using the regenerative power from the main DC / DC conversion unit 23 as the power source.

[0105] By performing the constant current charging control in this way, the built-in battery 16 can be charged using the regenerative power generated by the main DC / DC conversion unit 23 in the discharge test mode of the main charge / discharge unit 11, without wasting the regenerative power through heat exchange. In addition, in the constant current charging control, the current Isub supplied to the built-in battery 16 is controlled at a set constant current value, and the bus voltage VDC is within the range of 24.4 < VDC ≤ 25.0 [V], so that the charging of the built-in battery 16 can be stably performed.

[0106] As described above, when the main charge / discharge unit 11 is in the charge test mode, the bus voltage VDC is within the range of 21.6 [V] ≤ VDC ≤ 25.0 [V], and the output voltage VBAT of the built-in battery 16 is within the power supply voltage range of 9.2 [V] ≤ VBAT ≤ 13.0 [V], the sub-power supply control starts. In the sub-power supply control, the duty ratio controls the sub DC / DC conversion unit 51 so that the bus voltage VDC becomes a constant voltage of 24.5 [V]. It should be noted that in the sub-power supply control, the bus voltage VDC can be controlled within the range of 24.5 [V] ± 0.1 [V] including the allowable value ±0.1 [V].

[0107] After the sub-power supply control starts, when the bus voltage VDC rises to VDC > 24.5 [V], the main charge / discharge unit 11 is in the discharge test mode, and the main DC / DC conversion unit 23 may generate regenerative power, so the sub-power supply control will be immediately stopped.

[0108] In addition, after the start of the sub-power supply control, if the output voltage VBAT of the built-in battery 16 drops below 10.0 [V] due to the discharge of the built-in battery 16, the constant voltage output of the sub-DC / DC conversion unit 51 gradually decreases from 24.5 [V] at intervals of 0.1 [V], and then when VDC ≤ 24.0 [V], the sub-power supply control is stopped. The reason for not immediately stopping the sub-power supply control when the bus voltage VDC drops below 24.5 [V] is that this would cause the voltage fluctuation of the bus voltage VDC to become larger, having an adverse effect on the operation of the main DC / DC conversion unit 23. To avoid this situation, when stopping the sub-power supply control, the control bus voltage VDC is gradually decreased from 24.5 [V] to 24.0 [V]. Therefore, Figure 19 The shown area CV is the execution range of the sub-power supply control, that is, the area where power is supplied from the sub-DC / DC conversion unit 51 to the main DC / DC conversion unit 23.

[0109] By performing the sub-power supply control in this way, the stored power of the built-in battery 16 can be reused as the charging power of the main charge / discharge unit 11 in the charge test mode. In addition, in the sub-power supply control, the control bus voltage VDC is at 24.5 [V] which is higher than the 24 [V] output voltage of the AC / DC conversion unit 21, so that power can be reliably supplied from the sub charge / discharge unit 12 to the main DC / DC conversion unit 23.

[0110] It should be noted that when the main charge / discharge unit 11 is in the discharge test mode, in the area A0 where the voltage range is 24.0 [V] ≤ VDC ≤ 24.4 [V], the sub charge / discharge unit 12 is neither in the charging mode nor in the discharging mode, and the current ISUB does not flow. In the main charge / discharge unit 11, the discharge power and the internal consumption power are in a balanced state.

[0111] In addition, when the main charge / discharge unit 11 is in the discharge test mode or the charge test mode, the voltage range of 21.6 [V] ≤ VDC ≤ 24.0 [V] is the operation areas A1 and A2, where the output voltage of the AC / DC conversion unit 21 is applied to the main DC / DC conversion unit 23. In the operation area A2, since the terminals 23A and 23B of the main DC / DC conversion unit 23 are in a short-circuit state or the discharge power is very small, even when the main charge / discharge unit 11 is in the discharge test mode, the built-in battery 16 cannot be charged. In addition, in the operation area A1, even when the main charge / discharge unit 11 is in the charge test mode, the output voltage VBAT of the built-in battery 16 is very low, and power cannot be supplied from the sub charge / discharge unit 12 to the main DC / DC conversion unit 23. The areas A3 and A4 where the bus voltage VDC is lower than 21.6 [V] are the unavailable areas where the main charge / discharge unit 11 cannot perform the discharge test and the charge test.

[0112] In the above embodiments of the present invention, diodes 22 are provided as reverse current prevention elements on buses L1 and L2 between the AC / DC conversion unit 21 and the main DC / DC conversion unit 23, and transistors may also be provided instead. For example, as Figure 20 shown, an N-channel FET (field effect transistor) 48 may be provided between the AC / DC conversion unit 21 and the main DC / DC conversion unit 23. A conduction / turn-off signal is supplied from a gate control unit (not shown in the figure) to the gate of the FET 48. The FET 48 is controlled to turn off in the discharge test mode and to turn on in the charge test mode. The gate control unit may also detect the direction of current flow in the discharge test mode and the charge test mode respectively, and switch the conduction / turn-off of the FET 48 according to the detection results. By providing the N-channel FET 48 in place of the diode 22 in this way, the values of the voltage drop and power loss caused by the FET 48 can be reduced relative to the voltage drop and power loss caused by the diode 22. For example, when a current of 50 [A] flows through the diode 22, the voltage drop is 0.61 [V], and the power loss is 0.61 [V] × 50 [A] = 30.5 [W]. In contrast, when a current of 50 [A] flows between the drain and source of the FET 48, assuming the resistance between the drain and source is 1.6 [mΩ], the voltage drop is 50 [A] × 1.6 [mΩ] = 0.08 [V], and the power loss is (50 [A])2 × 1.6 [mΩ] = 4 [W]. Therefore, if the FET 48 is used, the voltage drop and power loss can be sufficiently reduced, and the heat generated in the FET 48 can be suppressed. Thus, there is also an advantage that a heat sink or a cooling fan does not need to be provided for the FET 48.

[0113] The specific values such as the respective voltage values of the batteries 15 and 16 and the voltage value between the buses L1 and L2 in the above embodiments are only an example of the present invention, and the present invention is not limited to these values. Of course, these values in the present invention can be changed according to the characteristics of each battery used and the charge and discharge conditions, etc.

[0114] Symbol description

[0115] 11: Main charge and discharge unit; 12: Sub charge and discharge unit; 14: AC power supply; 15: Battery under test; 16: Built-in battery; 21: AC / DC conversion unit; 22: Diode; 23: Main DC / DC conversion unit; 25, 55: Main switches; 26, 57: Sub switches; 27, 56, 65: Resistors; 28, 53, 59: Fuses; 29, 30, 52, 61: Voltage detection units; 31 - 34, 71 - 74: Semiconductor switch elements; 35, 75: Full-bridge circuits; 36, 37, 76, 77: Chokes; 38, 39, 78, 79: Capacitors; 40, 80: Current detection units; 41 - 44, 81 - 84: Flyback diodes; 46: Charge and discharge controller; 47: Test PC; 48: N-channel FET; 50: Main control unit; 51: Sub DC / DC conversion unit; 58: Simple discharge circuit; 60: Temperature sensor; 62: Sub control unit; 64: Discharge switch; L1, L2: Buses.

Claims

1. A battery charge and discharge test device, comprising: A DC power supply unit that outputs a constant voltage DC voltage between two buses; A main DC / DC conversion unit that includes a first full-bridge circuit composed of a plurality of switching elements and having two first input terminals and two first output terminals, the two buses being respectively connected to the two first input terminals, and the positive terminal and the negative terminal of the battery under test being respectively connected to the two first output terminals; A main charge and discharge control unit that performs duty cycle control on the conduction and cutoff of each of the plurality of switching elements of the first full-bridge circuit at a first period. In the charge test mode, a charging current is supplied to the battery under test via the first full-bridge circuit to charge the battery under test. In the discharge test mode, the stored charge of the battery under test is discharged via the first full-bridge circuit to supply the discharge power of the battery under test between the two buses; A sub-DC / DC conversion unit that has a second full-bridge circuit composed of a plurality of switching elements and having two second input terminals and two second output terminals, the two buses being respectively connected to the two second input terminals, and the positive terminal and the negative terminal of the built-in battery being respectively connected to the two second output terminals; And A sub charge and discharge control unit that performs duty cycle control on the conduction and cutoff of each of the plurality of switching elements of the second full-bridge circuit at a second period to charge and discharge the built-in battery; The battery charge and discharge test device is characterized in that The sub charge and discharge control unit performs the following control: When the output voltage of the built-in battery is within the power supply voltage range, perform sub-power supply control. The sub-power supply control supplies the discharge power of the built-in battery between the two buses via the second full-bridge circuit through the duty cycle control of the second period, so that the voltage between the buses is a first specified voltage value, the first specified voltage value being higher than the constant voltage value of the DC voltage. During the execution of the sub-power control, when the voltage between the buses is lower than the constant voltage value of the DC voltage, stop the sub-power supply control; During the execution of the sub-power supply control, when the voltage between the buses exceeds the first specified voltage value, stop the sub-power supply control and perform constant current charging control. The constant current charging control supplies the discharge power of the battery under test between the two buses as the power supply and charges the built-in battery via the second full-bridge circuit through the duty cycle control of the second period. During the execution of the constant current charging control, when the voltage between the buses drops below a second specified voltage value, stop the constant current charging control, the second specified voltage value being higher than the constant voltage value of the DC voltage and lower than the first specified voltage value.

2. The battery charge and discharge test device according to claim 1, characterized in that The sub charge and discharge control unit repeatedly determines whether the voltage between the buses drops during the execution of the sub-power supply control. When it is determined that the voltage between the buses drops, gradually reduce the first specified voltage value.

3. The battery charge and discharge test device according to claim 1 or 2, characterized in that During the execution of the constant current charging control, the sub-charge and discharge control unit repeatedly determines whether the voltage between the buses drops. When it determines that the voltage between the buses drops, it reduces the charging current to the built-in battery. When it does not determine that the voltage between the buses drops, it increases the charging current to the built-in battery.

4. The battery charge and discharge test device according to claim 1 or 2, characterized in that When the voltage between the buses is a low voltage or an overvoltage at which the charge and discharge test of the battery under test cannot be performed, the sub-charge and discharge control unit stops the control actions, which include the constant current charging control and the sub-power supply control.

5. The battery charge and discharge test device according to claim 1 or 2, characterized in that The first full-bridge circuit is composed of a first switching element, a second switching element, a third switching element, and a fourth switching element. One end of the first switching element and one end of the third switching element are connected to one of the two first input terminals. One end of the second switching element and one end of the fourth switching element are connected to the other of the two first input terminals. The other end of the first switching element and the other end of the second switching element are connected to one of the two first output terminals. The other end of the third switching element and the other end of the fourth switching element are connected to the other of the two first output terminals. One of the two first input terminals is connected to one of the two buses, and the other of the two first input terminals is connected to the other of the two buses. The two first output terminals are respectively connected to the two terminals of the battery under test via a first smoothing circuit, and the first smoothing circuit includes a first inductor and a first capacitor. The main charge and discharge control unit Within the first period, it constitutes a first charging current period, a first commutation current period immediately after the end of the first charging current period, a first discharge current period, and a second commutation current period immediately after the end of the first discharge current period. During the first charging current period, the first switching element and the fourth switching element are controlled to be turned on, and the second switching element and the third switching element are controlled to be turned off, and a charging current is supplied to the battery under test. During the first commutation current period, the first switching element to the fourth switching element are controlled to be turned off, and the first commutation current flows in the direction of the charging current via the freewheeling diodes of the second switching element and the third switching element respectively by the energy stored in the first inductor. During the first discharge current period, the first switching element and the fourth switching element are controlled to be turned off, and the second switching element and the third switching element are controlled to be turned on, and the discharge current flows out from the battery under test. During the second commutation current period, the first switching element to the fourth switching element are controlled to be turned off, and the second commutation current flows in the direction of the discharge current via the freewheeling diodes of the first switching element and the fourth switching element respectively by the energy stored in the first inductor. The duty ratio control of the first cycle is performed by the ratio of the first charging current period to the first discharging current period. The second full-bridge circuit is composed of a fifth switching element, a sixth switching element, a seventh switching element, and an eighth switching element. One end of the fifth switching element and one end of the seventh switching element are connected to one of the two second input terminals. One end of the sixth switching element and one end of the eighth switching element are connected to the other of the two second input terminals. The other end of the fifth switching element and the other end of the sixth switching element are connected to one of the two second output terminals. The other end of the seventh switching element and the other end of the eighth switching element are connected to the other of the two second output terminals. One of the two second input terminals is connected to one of the two buses, and the other of the two second input terminals is connected to the other of the two buses. The two second output terminals are respectively connected to the two terminals of the built-in battery via a second smoothing circuit, and the second smoothing circuit includes a second inductor and a second capacitor. The sub charge-discharge control unit Within the second cycle, it constitutes a second charging current period, a third commutation current period immediately after the end of the second charging current period, a second discharging current period, and a fourth commutation current period immediately after the end of the second discharging current period. During the second charging current period, the fifth switching element and the eighth switching element are controlled to be turned on, and the sixth switching element and the seventh switching element are controlled to be turned off, so as to supply a charging current to the built-in battery. During the third commutation current period, the fifth switching element to the eighth switching element are controlled to be turned off, and the third commutation current flows in the direction of the charging current of the built-in battery through the freewheeling diodes of the sixth switching element and the seventh switching element respectively by the energy stored in the second inductor. During the second discharging current period, the fifth switching element and the eighth switching element are controlled to be turned off, and the sixth switching element and the seventh switching element are controlled to be turned on, so that the discharging current flows out from the built-in battery. During the fourth commutation current period, the fifth switching element to the eighth switching element are controlled to be turned off, and the fourth commutation current flows from the built-in battery in the direction of the discharging current through the freewheeling diodes of the fifth switching element and the eighth switching element respectively by the energy stored in the second inductor. The duty ratio control of the second cycle is performed by the ratio of the second charging current period to the second discharging current period.

6. The battery charge and discharge test device according to claim 1 or 2, characterized in that A reverse current prevention element is provided on one of the two buses, and the reverse current prevention element prevents current from flowing from the main DC / DC conversion unit and the sub DC / DC conversion unit to the DC power supply unit.

7. A method for controlling the battery discharging power of a battery charge-discharge test device The battery charge-discharge test device includes: A DC power supply unit that outputs a constant voltage DC voltage between two buses; A main DC / DC conversion unit, which includes a first full-bridge circuit composed of a plurality of switching elements and having two first input terminals and two first output terminals, wherein the two buses are respectively connected to the two first input terminals, and the positive terminal and the negative terminal of the battery under test are respectively connected to the two first output terminals; A main charge-discharge control unit, which performs duty ratio control on the conduction and cutoff of each of the plurality of switching elements of the first full-bridge circuit at a first period. In the charging test mode, a charging current is supplied to the battery under test via the first full-bridge circuit, so as to charge the battery under test. In the discharging test mode, the stored charge of the battery under test is discharged via the first full-bridge circuit, so as to supply the discharging power of the battery under test between the two buses; A sub-DC / DC conversion unit, which has a second full-bridge circuit composed of a plurality of switching elements and having two second input terminals and two second output terminals, wherein the two buses are respectively connected to the two second input terminals, and the positive terminal and the negative terminal of the built-in battery are respectively connected to the two second output terminals; and A sub charge-discharge control unit, which performs duty ratio control on the conduction and cutoff of each of the plurality of switching elements of the second full-bridge circuit at a second period, and charges and discharges the built-in battery; The battery discharging power control method is characterized by including the following steps: When the output voltage of the built-in battery is within the power supply voltage range, the sub charge-discharge control unit executes sub power supply control. The sub power supply control supplies the discharging power of the built-in battery between the two buses via the second full-bridge circuit through the duty ratio control of the second period, so that the voltage between the buses is a first specified voltage value, and the first specified voltage value is higher than the constant voltage value of the DC voltage. During the execution of the sub power control, when the voltage between the buses is lower than the constant voltage value of the DC voltage, the sub power supply control is stopped; and During the execution of the sub power supply control, when the voltage between the buses exceeds the first specified voltage value, the sub charge-discharge control unit stops the sub power supply control and executes constant current charging control. The constant current charging control supplies the discharging power of the battery under test between the two buses as a power source through the duty ratio control of the second period, and charges the built-in battery via the second full-bridge circuit. During the execution of the constant current charging control, when the voltage between the buses drops below a second specified voltage value, the constant current charging control is stopped, and the second specified voltage value is higher than the constant voltage value of the DC voltage and lower than the first specified voltage value.

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