controller

Abstract

To prevent a large current from flowing from a second power-storage part to a first power-storage part.SOLUTION: According to a start of charging a power-storage device, when a voltage difference obtained by subtracting a voltage of a second power-storage part from a voltage of a first power-storage part is less than a predetermined voltage difference, controlled are a system main relay, a charging relay, a series-connecting relay, a parallel-connecting relay, and first and second neutral point relays in such a manner that only the first power-storage part is charged using external DC power in a state where the first and second neutral point relays are turned off. When the voltage difference is the predetermined voltage difference or more, controlled are the system main relay, the charging relay, the series-connecting relay, the parallel-connecting relay, and the first and second neutral point relays in such a manner that the first power-storage part and the second power-storage part are charged using external DC power in a state where the first and second neutral point relays are turned on.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a control device. [Background technology]

[0002] Conventionally, a control device of this type has been proposed for use in a power supply device having a storage battery that exchanges power with an inverter that drives a motor and has multiple switching elements and diodes connected in parallel in the opposite direction to each switching element, wiring that connects the neutral point of the motor stator and the positive terminal of the storage battery, and a switch provided on this wiring (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-93663 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, a power supply device including a power storage device having a first power storage unit and a second power storage unit has been proposed in which the neutral point of the motor and the positive electrode line of the second power storage unit are connected by a neutral line to switch between connecting the first power storage unit and the second power storage unit in series and connecting the first power storage unit and the second power storage unit in parallel. In such a power supply device, when the first power storage unit and the second power storage unit are connected in parallel, if the voltage of the first power storage unit is lower than the voltage of the second power storage unit, a forward voltage is applied to the diode of the inverter, causing a relatively large current to flow from the second power storage unit to the first power storage unit through the path of the second power storage unit, the neutral line, the motor, the inverter diode, and the first power storage unit. Such a large current has an undesirable effect on wiring such as the neutral line, and therefore it is desirable to suppress it.

[0005] A main object of the control device of the present disclosure is to prevent a large current from flowing from the second power storage unit to the first power storage unit. [Means for solving the problem]

[0006] The control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The control device disclosed herein is a control device used in a power supply device that supplies power to an inverter that drives a three-phase AC motor and has a plurality of switching elements and diodes connected in parallel in reverse to each of the switching elements, and the power supply device includes a power storage device having a first power storage unit and a second power storage unit, a system main relay having a positive-side relay attached to a positive line of a power line connecting the power storage device and the inverter and a negative-side relay attached to a negative line of the power line, and an external charging connector to which external DC power is supplied. a charging power line connecting the system main relay and the inverter of the power line, a charging relay attached to the charging power line, a series connection line connecting the first power storage unit and the second power storage unit in series, a series connection relay attached to the series connection line, a parallel connection line connecting the first power storage unit side of the series connection relay on the series connection line and the second power storage unit side of the negative side relay on the negative side line of the power line, a parallel connection relay attached to the parallel connection line, a neutral point line connecting a neutral point of a three-phase AC motor to a side of the series connection relay on the series connection line that is closer to the second power storage unit, a first neutral point relay attached to the neutral point line, and a second neutral point relay attached to the neutral point line on a side of the second power storage unit that is closer to the first neutral point relay, and a DC charging device that charges the power storage device using the external DC power, wherein when charging of the power storage device is started, if a voltage difference obtained by subtracting a voltage of the second power storage unit from a voltage of the first power storage unit is less than a predetermined difference, the first and second neutral point relays are turned off. The gist of the present invention is to control the system main relay, the charging relay, the series connection relay, the parallel connection relay, and the first and second neutral point relays so that only the first power storage unit is charged using the external DC power in a state where the voltage difference is equal to or greater than the predetermined difference, and to control the system main relay, the charging relay, the series connection relay, the parallel connection relay, and the first and second neutral point relays so that the first and second power storage units are charged using the external DC power with the first and second neutral point relays turned on when the voltage difference becomes equal to or greater than the predetermined difference. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the outline of the configuration of a power supply device 20. [Figure 2] 10 is a flowchart showing an example of a charging start process. [Figure 3] FIG. 4 is an explanatory diagram for explaining the on / off state of a relay. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing an outline of the configuration of a power supply device 20 including a control device of the present embodiment. The power supply device 20 of the embodiment is configured as a device that supplies power to an inverter 24 that drives a motor 22. The power supply device 20 includes a battery 26 as an electricity storage device, a system main relay 28, a first capacitor 34, a DC charging device 40, and a control device 60.

[0010] The motor 22 is configured as a well-known three-phase AC motor, for example, including a rotor with a permanent magnet attached to its outer surface and a stator around which three-phase coils are wound. The inverter 24 is configured with six transistors T1-T6 as switching elements and six diodes D1-D6 connected in parallel to the transistors T1-T6 in reverse directions. The transistors T1-T6 are arranged in pairs, two at a time, so that one is on the source side and the other is on the sink side of the positive and negative buses that the inverter 24 shares as a power line 30. The transistors T1-T6 are connected to the three-phase coils (U-phase, V-phase, and W-phase) of the motor 22 at their respective junctions. When a voltage is applied between the positive and negative buses, the inverter 24 controls the proportion of the on-time of the paired transistors T1-T6 to generate a rotating magnetic field in the three-phase coils, thereby driving the motor 22 to rotate. A first smoothing capacitor 34 is connected to the power line 30.

[0011] The battery 26 includes a first cell 26a as a first power storage unit and a second cell 26b as a second power storage unit having the same terminal voltage as the first cell 26a, and is connected to a power line 30. The first cell 26a and the second cell 26b are configured as, for example, lithium-ion secondary batteries or nickel-metal hydride secondary batteries. At least one of the first cell 26a and the second cell 26b may be a capacitor.

[0012] The system main relay 28 is attached to the power line 30. The system main relay 28 includes a positive side relay SMRB, a negative side relay SMRG, and a precharge circuit. The positive side relay SMRB is attached to a positive side line 30B of the power line 30. The negative side relay SMRG is attached to a negative side line 30G of the power line 30. The precharge circuit has a precharge resistor R and a precharge relay SMRP connected in series to bypass the negative side relay SMRG.

[0013] The DC charging device 40 includes an external charging connector 42, a charging power line 43, a charging relay 44, a series connection line 45, a series connection relay DCR, a parallel connection line 46, a parallel connection relay DCRNG, a neutral line 47, first and second neutral point relays DCRN and DCRNB, and a second capacitor 48. The external charging connector 42 is connected to an external DC power supply and receives DC power (external DC power) from the outside. The charging power line 43 is connected to the external charging connector 42 and is also connected to the power line 30 between the system main relay 28 and the inverter 24. The charging relay 44 is attached to the charging power line 43. The series connection line 45 connects the first battery 26a and the second battery 26b in series. The series connection relay DCR is attached to the series connection line 45. The parallel connection line 46 connects the first battery 26a side of the series connection relay DCR of the series connection line 45 to the second battery 26b side of the negative side relay SMRG and pre-charge circuit of the negative side line 30G of the power line 30. The parallel connection relay DCRNG is attached to the parallel connection line 46. The neutral point line 47 connects the neutral point of the motor 22 to the second battery 26b side of the series connection relay DCR of the series connection line 45. The first neutral point relay DCRN is attached to the neutral point line 47. The second neutral point relay DCRNB is attached to the neutral point line 47 on the second battery 26b side of the first neutral point relay DCRN. The second capacitor 48 is installed between the first neutral relay DCRN and the second neutral relay DCRNB on the neutral line 47, and on the inverter 24 side of the negative side relay SMRG and the precharge circuit on the negative side line 30G of the power line 30.

[0014] Although not shown, the control device 60 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory, input / output ports, and communication ports. Signals from various sensors are input to the control device 60 via the input ports. Examples of signals input to the control device 60 include a battery voltage Vb1 from a voltage sensor 26c that detects the voltage of the first battery 26a and a battery voltage Vb2 from a voltage sensor 26d that detects the voltage of the second battery 26b. The control device 60 is also connected to a communication line for communicating with an external power source via the external charging connector 42. Various control signals are output from the control device 60 via the output ports. Examples of signals output from the control device 60 include a switching control signal to transistors T1 to T6 of the inverter 24, a drive control signal to the system main relay 28, a drive control signal to the charging relay 44, a drive control signal to the series connection relay DCR, a drive control signal to the parallel connection relay DCRNG, a drive control signal to the first neutral point relay DCRN, and a drive control signal to the second neutral point relay DCRNB.

[0015] When an external power source is connected to the external charging connector 42 of the DC charging device 40, the control device 60 inputs the voltage Vd of DC power supplied by the external power source (external DC voltage Vd) via a communication line. When the external DC voltage Vd is equal to the rated voltage V1 of the battery 26 when the first battery 26a and the second battery 26b are connected in series, the control device 60 connects the first battery 26a and the second battery 26b in series and charges the battery 26 through a first charging by the DC charging device 40, and when the external DC voltage Vd is 0.5 times the rated voltage V1, the control device 60 charges the battery 26 through a second charging by the DC charging device 40. The first charging is not central to the present invention and will not be described here. In the second charging mode, the control device 60 turns on the positive relay SMRB and negative relay SMRG of the system main relay 28, the charging relay 44, the parallel connection relay DCRNG, and the first and second neutral relays DCRN and DCRNB, and turns off the precharge relay SMRP and series connection relay DCR of the system main relay 28. This connects the first battery 26a and the second battery 26b in parallel. The first battery 26a is then charged via a current path that runs from the positive line of the charging power line 43, through the positive line 30B of the power line 30, the first battery 26a, the parallel connection line 46, and the negative line 30G of the power line 30, and returns to the negative line of the charging power line 43. The second battery 26b is charged via a current path that runs from the positive side line of the charging power line 43 through the positive side line 30B of the power line 30, any one of the diodes D1 to D3 of the inverter 24, the motor 22, the neutral line 47, the second battery 26b, the negative side line 30G of the power line 30, and back to the negative side line of the charging power line 43.

[0016] Next, the operation when the second charging is started will be described. Fig. 2 is a flowchart showing an example of the charging start process executed by the control device 60. This routine is executed when an external power supply is connected to the external charging connector 42 of the DC charging device 40 and the external DC voltage Vd input from the external power supply is 0.5 times the rated voltage V1.

[0017] When this routine is executed, the CPU of the control device 60 turns on the positive-side relay SMRB and negative-side relay SMRG of the system main relay 28, the parallel connection relay DCRNG, and the charging relay 44, and turns off the precharge relay SMRP, series connection relay DCR, and first and second neutral relays DCRN and DCRNB of the system main relay 28 (S100). FIG. 3 is an explanatory diagram for explaining the on / off states of the relays when S100 is executed. In the diagram, thick solid lines indicate the current paths when S100 is executed. In S100, the first battery 26a is charged, but the second battery 26b is not charged, via a current path that runs from the positive side of the charging power line 43 through the positive side line 30B of the power line 30, the first battery 26a, the parallel connection line 46, and the negative side line 30G of the power line 30 and returns to the negative side of the charging power line 43.

[0018] Next, the battery voltages Vb1 and Vb2 from the voltage sensors 26c and 26d are input (S100). Then, the battery voltage Vb2 is subtracted from the battery voltage Vb1 to calculate the voltage difference ΔVb (S120). Then, it is determined whether the voltage difference ΔVb is equal to or greater than a predetermined difference Vref (S130). The predetermined difference Vref is a threshold value for determining whether the voltage applied to the diodes D1 to D3 of the inverter 24 is in the reverse direction and no current is flowing, and is set to 0 V or a voltage slightly greater than 0 V. If the voltage difference ΔVb is less than the predetermined difference Vref, it is determined that a forward voltage is being applied to the diodes D1 to D3 of the inverter 24, and that when the second charging described above is performed, current will flow from the second battery 26b to the first battery 26a via the neutral line 47, the motor 22, or one of the diodes D1 to D3, and the process returns to S100.

[0019] When the voltage difference ΔVb is equal to or greater than the predetermined difference Vref in S130, it is determined that a reverse voltage is being applied to the diodes D1 to D6 of the inverter 24, and that even if the second charging described above is performed, no current will flow from the second battery 26b to the first battery 26a via the motor 22 and any of the diodes D1 to D3.Then, the first and second neutral point relays DCRN and DCRNB are turned on (S140), the second charging is started (S150), and this routine is terminated. 3, the first battery 26a is charged via the current path indicated by the thick solid line, and the second battery 26b is charged via the current path indicated by the thick dashed line in Fig. 3, i.e., a current path from the positive side of the charging power line 43 via the positive side line 30B of the power line 30, any one of the diodes D1 to D3 of the inverter 24, the motor 22, the neutral line 47, the second battery 26b, the negative side line 30G of the power line 30, and back to the negative side line of the charging power line 43. In this way, the second charging starts when the voltage difference ΔVb is equal to or greater than the predetermined difference Vref, which prevents a relatively large current from flowing from the second battery 26b to the first battery 26a via the motor 22 and any one of the diodes D1 to D3.

[0020] According to the control device of this embodiment described above, when charging of the battery 26 is started, if the voltage difference ΔVb is less than the predetermined difference Vbref, the first and second neutral point relays DCRN and DCRNB are turned off and the system main relay 28, the charging relay 44, the series connection relay DCR, the parallel connection relay DCRNG, and the first and second neutral point relays DCRN and DCRNB are controlled so that only the first battery 26a is charged using external DC power, and when the voltage difference ΔVb becomes greater than or equal to the predetermined difference Vref, the second charging is performed, thereby preventing a relatively large current from flowing from the second battery 26b to the first battery 26a.

[0021] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0022] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Explanation of symbols]

[0023] 22 motor, 26 battery, 60 control device, D1 to D6 diodes.

Claims

[Claim 1] 1. A control device used in a power supply device that supplies power to an inverter that has a plurality of switching elements and diodes connected in parallel in reverse directions to each of the switching elements and drives a three-phase AC motor, The power supply device a power storage device including a first power storage unit and a second power storage unit; a system main relay including a positive-side relay attached to a positive-side line of a power line connecting the power storage device and the inverter, and a negative-side relay attached to a negative-side line of the power line; a DC charging device comprising: a charging power line connecting an external charging connector to which external DC power is supplied, the system main relay of the power line, and the inverter; a charging relay attached to the charging power line; a series connection line connecting the first power storage unit and the second power storage unit in series; a series connection relay attached to the series connection line; a parallel connection line connecting a side of the series connection relay on the series connection line to a side of the second power storage unit on a negative side line of the power line to a side of the negative side relay on the negative side line of the power line; a parallel connection relay attached to the parallel connection line; a neutral point line connecting a neutral point of the three-phase AC motor and a side of the second power storage unit on the series connection line to the series connection relay; a first neutral point relay attached to the neutral point line; and a second neutral point relay attached to the neutral point line on a side of the second power storage unit on the first neutral point relay Equipped with When charging of the power storage device is started, if a voltage difference obtained by subtracting the voltage of the second power storage unit from the voltage of the first power storage unit is less than a predetermined difference, the system main relay, the charging relay, the series connection relay, the parallel connection relay, and the first and second neutral point relays are controlled so that only the first power storage unit is charged using the external DC power with the first and second neutral point relays turned off, and when the voltage difference becomes equal to or greater than the predetermined difference, the system main relay, the charging relay, the series connection relay, the parallel connection relay, and the first and second neutral point relays are controlled so that the first power storage unit and the second power storage unit are charged using the external DC power with the first and second neutral point relays turned on. Control device.

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