JP5609226B2 - Power supply - Google Patents

Description

  The present invention relates to a configuration of a power supply device.

  In recent years, many hybrid vehicles and electric vehicles have been used. Such an electric vehicle uses a chargeable / dischargeable secondary battery as a power supply device for driving the vehicle. As the secondary battery, a lithium ion secondary battery, a nickel hydride secondary battery, or the like is often used. An electric vehicle is required to have a long cruising distance and high acceleration / deceleration performance, but due to the weight of the secondary battery, the amount of secondary battery that can be mounted on the vehicle cannot be increased so much. For this reason, a power supply device in which a secondary battery and a large-capacity capacitor are connected in parallel has been proposed (see, for example, Patent Document 1).

  In a power supply device in which a secondary battery and a capacitor are connected in parallel, it is necessary to connect the capacitor to the power supply system of the electric vehicle when starting the vehicle. When the capacitor is connected to the power supply system of the vehicle, if the voltage difference between the capacitor and the secondary battery or the power supply system is large, an inrush current flows to the capacitor and the capacitor may be damaged. For this reason, when the voltage of the capacitor is low, the capacitor is connected to the secondary battery after the engine is started and the capacitor is precharged with the electric power generated by the motor generator until the voltage becomes substantially the same as that of the secondary battery. When the voltage of the capacitor is higher than the voltage of the secondary battery, the capacitor of the power supply system to which the capacitor is connected in parallel is charged with the power of the secondary battery until it becomes approximately the same voltage as the capacitor, Thereafter, a method of connecting a capacitor and a power supply system has been proposed (see, for example, Patent Document 1).

JP 2006-158173 A

  In the conventional hybrid vehicle described in Patent Document 1, since the motor generator is directly driven by the output power of the capacitor, or the back electromotive force of the motor generator is directly regenerated and stored, the capacitor has a high voltage and a large capacity. However, there is a problem that the system becomes large. Therefore, a method of connecting a voltage converter between a power supply system of an electric vehicle and a capacitor to obtain a low-voltage capacitor has been studied.

  On the other hand, in recent years, in a hybrid vehicle, a secondary battery mounted on the vehicle has been charged from an external power source. For example, a method in which a 100V or 200V AC power supply is connected to a vehicle for commercial use, converted into DC by a charger mounted on the vehicle, and boosted to a voltage that can charge the secondary battery, and the secondary battery is charged. Is used. In recent years, secondary batteries are often charged by a charging station that can supply high-voltage DC power that can be directly charged to secondary batteries.

  In recent years, clean power sources such as solar cell power generation, wind power generation, and fuel cells have been attracting attention in consideration of the environment. And it is going to be performed by charging the electric power generated by such a power generation method to the secondary battery of the vehicle to make electric power for running. However, the output of such electric power is direct current with a lower voltage than the secondary battery of the vehicle, and the secondary battery cannot be charged as it is. For example, it is necessary to mount a separate voltage converter on the vehicle. There is a problem that the structure of the electric vehicle becomes complicated. In recent years, a solar cell panel is mounted on an electric vehicle and a secondary battery is being charged by the output of the solar cell. There is a problem that a separate voltage converter or charger is required to charge the secondary battery. On the other hand, when the voltage of the external power supply is higher than that of the secondary battery, there is a problem that a voltage converter and a charger for stepping down the voltage of the external power supply are required and the structure becomes complicated. .

  Accordingly, an object of the present invention is to charge a secondary battery mounted on a vehicle by an external DC power supply with a simple configuration.

The power supply device of the present invention includes a first power storage device to which a first input / output line that inputs and outputs power is connected, and a second power storage device to which a second input and output line that inputs and outputs power is connected. the a, the first power storage device and said first and said second power storage devices are connected in parallel via a second output line, said first input output line and the second the power supply device including a voltage converter provided, the between the connection point and the second power storage device and the input output lines, said second power storage device, charging terminal to be connected to an external power source An on / off switch is provided between the second power storage device and the charging terminal, the voltage converter includes a plurality of switching elements, and a control unit for turning on and off the switching elements and the on / off switch is provided. And the control unit turns on and off the switching element of the voltage converter. After charging the second power storage device with the power of the first power storage device to the same voltage as the external power supply, and after charging the second power storage device with the first charging means And an external power supply connection means for connecting the external power supply and the second power storage device by turning on the on / off switch .

  In the power supply device of the present invention, the control unit connects the external power supply and the second power storage device by the external power supply connection unit, and then turns on and off the switching element of the voltage converter to power the external power supply. It is also preferable to have second charging means for charging the first power storage device.

  The present invention has an effect that a secondary battery mounted on a vehicle can be charged by an external DC power supply with a simple configuration.

It is a systematic diagram which shows the structure of the power supply device in embodiment of this invention. It is a flowchart which shows operation | movement of the power supply device in embodiment of this invention. It is explanatory drawing which shows operation | movement of the power supply device in embodiment of this invention. It is explanatory drawing which shows the control block of the power supply device in embodiment of this invention. It is a systematic diagram which shows the structure of the power supply device in other embodiment of this invention.

  Hereinafter, the power supply device of the present embodiment will be described with reference to the drawings. As shown in FIG. 1, the power supply device 100 of this embodiment mounted on an electric vehicle includes a chargeable / dischargeable secondary battery 18 that is a first power storage device, and an inverter that boosts the power of the secondary battery 18. 12 is connected between the boost converter 30 supplied to the capacitor 12, the capacitor 19 as the second power storage device connected in parallel to the secondary battery 18 with respect to the inverter 12, and the capacitor 19 and the inverter 12. Are provided with a voltage converter 20 for converting the input / output voltage and charging terminals 56 and 57 provided on the capacitor 19. A motor generator 11 for driving the vehicle is connected to the inverter 12.

  The positive input / output line 48 of the secondary battery 18 is connected to the low voltage input / output line 47 of the boost converter 30, and the negative input / output line 49 of the secondary battery 18 is connected to the reference input / output line 46 of the boost converter 30. ing. A system main relay 17 that shuts off the secondary battery 18 and the boost converter 30 is provided on the input / output lines 48 and 49 of the secondary battery 18. Further, a discharge resistance line relay 15 in which a discharge resistor 16 is inserted in series is provided on the plus side input / output line 48 of the secondary battery 18. A low voltage capacitor 14 is provided between the low voltage side input / output line 47 and the reference input / output line 46 of the boost converter 30.

  Boost converter 30 includes an upper arm switching element 31, an upper arm diode 32 connected in antiparallel with upper arm switching element 31, a lower arm switching element 33 connected in series with upper arm switching element 31, and a lower arm. A lower arm diode 34 connected in reverse parallel to the switching element 33, a low voltage side input / output line 47 connected between the upper arm switching element 31 and the lower arm switching element 33, and a low voltage side input / output line 47 The lower arm switching element 33 is connected to the reference input / output line 46, and the high arm side input / output line 45 connected to the opposite side of the low arm side input / output line 47 of the upper arm switching element 31. Has been. The high-voltage side input / output line 45 and the reference input / output line 46 of the boost converter 30 are connected to the plus-side input / output line 41 and the minus-side input / output line 42 of the inverter 12 at connection points 43 and 44, respectively. A high voltage capacitor 13 is connected between the input / output lines 41 and 42 of the inverter 12.

  The voltage converter 20 includes a secondary side upper arm switching element 21, a secondary side upper arm diode 22 connected in antiparallel with the secondary side upper arm switching element 21, and a secondary side upper arm switching element 21 in series. A secondary side lower arm switching element 23 connected to the secondary side, a secondary side lower arm switching element 23 connected in reverse parallel to the secondary side lower arm switching element 23, a primary side upper arm switching element 26, and an upper side of the primary side Primary side upper arm diode 27 connected in antiparallel with arm switching element 26, primary side lower arm switching element 28 connected in series with primary side upper arm switching element 26, and reverse to primary side lower arm switching element 28 A primary side lower arm diode 29, a secondary side upper arm switching element 21, and a secondary side lower arm connected in parallel. Reactor 25 connected to connection line 53a between switching element 23, primary upper arm switching element 26 and primary lower arm switching element 28, and one end of secondary upper arm switching element 21 are connected. The secondary side input / output line 51, the primary side input / output line 53 connected to one end of the primary side upper arm switching element 26, and the connection line 53a of each lower arm switching element 23, 28 are connected to the opposite side. And a reference input / output line 52. The primary side input / output line 53 of the voltage converter 20 and the primary side of the reference input / output line 52 are respectively connected to the plus side input / output line 54 and the minus side input / output line 55 of the capacitor 19. Further, the secondary side input / output line 51 of the voltage converter 20 and the secondary side of the reference input / output line 52 are connected to connection points 43 and 44, respectively, and the secondary side input / output line 51 is connected to the high voltage side input of the boost converter 30. The output line 45 and the positive input / output line 41 of the inverter 12 are electrically connected to each other. The secondary side of the reference input / output line 52 of the voltage converter 20 is the reference input / output line 46 of the boost converter 30 and the negative of the inverter 12. The side input / output line 42 is connected.

  A positive charge line 56 is connected to the positive input / output line 54 of the capacitor 19, and a negative charge line 57 is connected to the negative input / output line 55 of the capacitor 19. The positive charging line 56 is provided with an external power input switch 60 that turns the positive charging line 56 on and off. In addition, charging terminals 58 and 59 to which charging plugs 71 and 72 of a DC external power supply 70 are connected are provided at one ends of the external power input switch 60 and the negative charging line 57.

  The positive input / output line 48, the negative input / output line 49 of the secondary battery 18, the low voltage input / output line 47, the reference input / output line 46, and the high voltage input / output line 45 of the boost converter 30 are connected to the first input / output line. The secondary input / output line 51, the primary input / output line 53, the reference input / output line 52, the positive input / output line 54, and the negative input / output line 55 of the capacitor 19 are connected to the second input / output line. Configure the output line.

  A voltage sensor 63 for detecting the output voltage of the secondary battery 18 is provided on the output side of the secondary battery 18, and the input / output current of the secondary battery 18 is detected on the plus-side input / output line 48 of the secondary battery 18. A current sensor 62 is provided. Further, a voltage sensor 65 for detecting the output voltage of the capacitor 19 is provided on the output side of the capacitor 19, and a current sensor 64 for detecting the input / output current of the capacitor 19 is provided on the plus side input / output line 54 of the capacitor 19. It has been. The high voltage capacitor 13 is provided with a voltage sensor 61 that detects the voltage across the high voltage capacitor 13.

  The inverter 12, the switching elements 31 and 33 of the boost converter 30, the switching elements 21, 23, 26 and 28 of the voltage converter 20, the system main relay 17, the discharge resistance line relay 15, and the external power input switch 60 are controlled by a control unit 80. And is configured to operate according to a command from the control unit 80. The system main relay 17 can simultaneously turn on / off each contact point of the positive side input / output line 48 and the negative side input / output line 49 of the secondary battery 18 according to a command from the control unit 80, or only one of the contact points. Can also be turned on and off. The motor generator 11, the voltage sensors 61, 63, 65, the current sensors 62, 64, the secondary battery 18, and the capacitor 19 are connected to the control unit 80. The control unit 80 has a voltage value and a current value of each unit. The state of the motor generator 11, the secondary battery 18, and the capacitor 19 is input. The control unit 80 is a computer including a CPU that performs signal processing therein and a storage unit that stores control programs and data.

  An operation of charging the secondary battery 18 by connecting the external power supply 70 to the power supply apparatus 100 configured as described above will be described. The electric vehicle equipped with the power supply device 100 is stopped, the high-voltage capacitor 13 and the capacitor 19 are discharged, the voltage thereof is substantially zero, and the secondary battery 18 is in a range where the remaining capacity (SOC) can be charged. . The external power source 70 is a DC power source, and is, for example, a solar battery, another secondary battery, or the like, and its voltage is lower than that of the secondary battery 18 mounted on the electric vehicle. For example, when the voltage of the secondary battery 18 is 200V or 300V, the voltage of the external power supply 70 is about 50V. In the initial state, all the switching elements 21, 23, 26, 28, 31, 33 are off, and the relays 15, 17 are also off.

  As shown in step S <b> 101 of FIG. 2, the charging plugs 71 and 72 of the external power supply 70 are inserted into the charging terminals 58 and 59 of the capacitor 19 by the operator. Then, a signal in which the external power source 70 is inserted into the charging terminals 58 and 59 through a signal line (not shown) is input to the control unit 80. Then, as shown in step S <b> 102 of FIG. 2, the control unit 80 turns on the discharge resistance line relay 15 and simultaneously turns on the contact of the system main relay 17 on the negative input / output line 49 side of the secondary battery 18. . As a result, the secondary battery 18 is connected to the boost converter 30 via the discharge resistor 16. Then, the current of the secondary battery 18 flows from the positive input / output line 48 to the discharge resistance line relay 15 and from the discharge resistance 16 to the low voltage side input / output line 47 of the boost converter 30. 2 flows from the reactor 25 through the upper arm diode 32 to the high-voltage input / output line 45, flows from the high-voltage input / output line 45 through the connection point 43, and flows to the positive input / output line 41 of the inverter 12. As shown in S103, the high voltage capacitor 13 starts to be charged. At this time, the negative input / output line 49 of the secondary battery 18 is connected to the negative input / output line 42 of the inverter 12 via the negative contact of the system main relay 17, the reference input / output line 46 of the boost converter 30, and the connection point 44. It is connected. When the high voltage capacitor 13 is charged, the voltage VH across the high voltage capacitor 13 gradually increases as shown in FIG.

  As shown in step S104 of FIG. 2, the control unit 80 acquires the voltage across the high-voltage capacitor 13 by the voltage sensor 61, and determines whether or not the voltage has been boosted to a predetermined voltage such as the voltage VB of the secondary battery 18, for example. Monitor. Then, when the voltage of the high voltage capacitor 13 becomes substantially the same voltage as the voltage VB of the secondary battery 18, for example, the control unit 80, as shown in step S105 of FIG. Is turned off, the positive side contact of the system main relay 17 of the secondary battery 18 is turned on, and the secondary battery 18 and the boost converter 30 are directly connected without going through the discharge resistor 16. 2, the control unit 80 turns on the upper arm switching element 31 of the boost converter 30 to charge the secondary battery 18 from the high-voltage side input / output line 45 to charge the secondary battery 18. The positive side input / output line 48 is prepared to allow a large current to flow.

  As shown in step S107 of FIG. 2, the control unit 80 keeps the secondary side lower arm switching element 23, the primary side upper arm switching element 26, and the primary side lower arm switching element 28 of the voltage converter 20 off, A step-down operation for turning on and off the secondary-side upper arm switching element 21 is started, and the voltage of the high-voltage capacitor 13 that has been stepped up to a voltage VB substantially the same as that of the secondary battery 18 is stepped down to start charging the capacitor 19. When the secondary upper arm switching element 21 of the voltage converter 20 is turned on, the plus side of the high voltage capacitor 13 is connected to the plus side input / output line 41 of the inverter 12, the connection point 43, and the secondary side input / output of the voltage converter 20. The electric charge stored in the high voltage capacitor 13 connected to the reactor 25 via the line 51 and the secondary upper arm switching element 21 is accumulated in the reactor 25 as electric energy. When the secondary side upper arm switching element 21 of the voltage converter 20 is turned off, the electric power stored in the reactor 25 connects the reactor 25, the primary side upper arm diode 27, the capacitor 19, and the secondary side lower arm diode 24. The capacitor 19 is charged through the circuit. At this time, the voltage of the primary side input / output line 53 of the voltage converter 20 is stepped down from the voltage of the secondary side input / output line 51. The voltage to be stepped down is determined by the ON / OFF duty ratio of the secondary-side upper arm switching element 21 of the voltage converter 20. Since the capacitor 19 is in a discharged state in the initial state and its voltage is substantially zero, when the capacitor 19 is started to be charged, the duty ratio of the secondary-side upper arm switching element 21 is reduced. Then, charging is started so that no inrush current flows through the capacitor 19. The charging control of the capacitor 19 may be feedback control so that the current flowing into the capacitor 19 by the current sensor 64 and the voltage sensor 65 becomes an optimum charging current.

  When charging of the capacitor 19 is started, the voltage of the capacitor 19 gradually increases as shown in FIG. As shown in step S <b> 108 of FIG. 2, the control unit 80 acquires the voltage of the capacitor 19 using the voltage sensor 65, and checks whether the voltage of the capacitor 19 is substantially the same as the voltage of the external power supply 70. Then, when the voltage of the capacitor 19 becomes substantially the same as the voltage of the external power supply 70, the control unit 80 turns on the external power supply input switch 60 as shown in step S109 of FIG. Since the voltage of the capacitor 19 is substantially the same as the voltage of the external power supply 70, a large inrush current does not flow when the external power input switch 60 is turned on.

When the external power input switch 60 is turned on, as shown in step S110 of FIG. 2, the control unit 80 turns off the primary side lower arm switching element 28 and keeps the primary side upper arm switching element 26 on. The secondary side upper arm switching element 21 and the secondary side lower arm switching element 23 are turned on / off, and the voltage converter 20 starts a boosting operation. The step-up operation is performed as follows. First, the secondary side upper arm switching element 21 is turned off, and the secondary side lower arm switching element 23 is turned on to store energy in the reactor 25. Next, when the secondary side lower arm switching element 23 is turned off, the electric power boosted by the energy stored in the reactor 25 flows from the secondary side upper arm diode 22 to the secondary side input / output line 51. At this time, the secondary-side upper arm switching element 21 may be turned on. The voltage and current of power output from the secondary input / output line 51 of the voltage converter 20 can be changed by changing the on / off duty of the switching elements 21 and 23. As shown in FIG. 4, the control unit 80 acquires the voltage VH of the high voltage capacitor 13 and the voltage VC of the capacitor 19 by the voltage sensors 61 and 68, and sets the ratio of the voltage VC of the capacitor 19 to the voltage VH of the high voltage capacitor 13. The secondary side lower arm switching element 23 is set as an on / off duty ratio, and the difference between the current value acquired by the current sensor 64 and the charging current to the secondary battery 18 is fed back to the duty ratio to the secondary battery 18. controls to the current flowing through the charging current setting value a ₁ of the rechargeable battery 18 shown in FIG.

  As shown in step S <b> 111 of FIG. 2, the controller 80 acquires the remaining capacity (SOC) of the secondary battery 18 when charging of the secondary battery 18 is started. This may be obtained by adding the current acquired by the current sensor 62 to the initial remaining capacity (SOC) of the secondary battery 18 to calculate the remaining capacity (SOC), or by the voltage sensor 63 to determine the voltage of the secondary battery 18. And the remaining capacity (SOC) may be obtained from the voltage and the temperature of the secondary battery 18. Then, as shown in step S112 of FIG. 2, when the remaining capacity (SOC) of the secondary battery 18 becomes equal to or greater than a predetermined value, the control unit 80 controls the secondary lower arm switching element 23 of the voltage converter 20. The on / off operation is stopped, and the switching elements 21, 23, 26, and 28 of the voltage converter 20 are all turned off. Then, as shown in step S114 of FIG. 2, control unit 80 turns off external power input switch 60, and turns off upper arm switching element 31 of boost converter 30 as shown in step S115 of FIG. Then, the system main relay 17 is turned off, and the charging operation of the secondary battery 18 by the external power source 70 is finished.

  The case where the voltage of the external power supply 70 is lower than the voltage VB of the secondary battery 18 has been described above. However, the voltage of the external power supply 70 is the same as the voltage VB of the secondary battery 18 or higher than the voltage VB of the secondary battery 18. In this case, the switching elements 26 and 28 on the primary side of the voltage converter 20 are used, and the voltage from the high voltage capacitor 13 is first boosted to boost the capacitor 19 to a voltage similar to the voltage of the external power supply 70, and then Then, the switching elements 26 and 28 on the primary side of the voltage converter 20 are turned on and off to step down the voltage of the external power supply 70 to the voltage VH of the high voltage capacitor 13 to charge the secondary battery 18.

  Further, the voltage converter 20 outputs a voltage higher than the voltage VB of the secondary battery 18 to charge the high-voltage capacitor 13 until the voltage becomes higher than the voltage VB of the secondary battery 18. The secondary battery 18 may be charged by decreasing the voltage of the high-voltage capacitor 13 by turning on and off the arm switching element 31.

  In the embodiment described above, the charging terminals 58 and 59 with the external power supply 70 are attached to the capacitor 19 connected in parallel to the power supply system of the electric vehicle via the voltage converter 20, and the external DC power supply is used. The secondary battery 18 mounted on the vehicle can be charged. In addition, since the secondary battery 18 can be charged by stepping up or down the voltage of the external power supply 70 by the voltage converter 20, there is an effect that it can be widely applied to many kinds of power supplies. In addition, after the secondary battery 18 first charges the capacitor 19 until the voltage of the capacitor 19 becomes equal to the voltage of the external power supply, the external power supply input switch 60 is turned on to connect the external power supply 70 and the capacitor 19. Thus, there is an effect that it is possible to prevent the capacitor 19 from being damaged by preventing an inrush current from flowing therethrough.

  Another embodiment of the present invention will be described with reference to FIG. Parts similar to those of the embodiment described above with reference to FIGS. 1 to 3 are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 5, in the present embodiment, the voltage converter 20a according to the embodiment described with reference to FIGS. 1 to 3 performs only the step-up without the respective switching elements and diodes on the primary side. It is what. When the voltage of the external power source 70 is lower than the voltage of the secondary battery 18, the voltage converter 20 that can step up and step down the voltage of the external power source 70 like the voltage converter 20 of the embodiment shown in FIG. 1. Instead, a voltage converter 20a that can only boost the voltage of the external power supply 70 may be used. About operation | movement, it is the same as that of embodiment described previously, and the effect is also the same. This embodiment has an effect that the secondary battery 18 can be charged by the external power source 70 with a simpler configuration because the number of switching elements and diodes is smaller than that of the previously described embodiment. When the voltage VB of the secondary battery 18 is lower than the voltage of the external power supply 70, the configuration of the voltage converter 20 is changed to the primary side upper arm switching element 26, the primary side lower arm switching element 28 shown in FIG. The voltage converter may include only the diodes 27 and 29 and the reactor 25, and only reduces the voltage of the external power supply 70.

  In each of the embodiments described above, the case where the first power storage device is the secondary battery 18 and the second power storage device is the capacitor 19 has been described. However, the second power storage device may be a secondary battery, One power storage device may be a capacitor.

  11 Motor Generator, 12 Inverter, 13 High Voltage Capacitor, 14 Low Voltage Capacitor, 15 Discharge Resistance Line Relay, 16 Discharge Resistance, 17 System Main Relay, 18 Secondary Battery, 19 Capacitor, 20, 20a Voltage Converter, 21 On Secondary Side Arm switching element, 22 Secondary side upper arm diode, 23 Secondary side lower arm switching element, 24 Secondary side lower arm diode, 25, 35 reactor, 26 Primary side upper arm switching element, 27 Primary side upper arm diode, 28 Primary side lower arm switching element, 29 Primary side lower arm diode, 30 Boost converter, 31 Upper arm switching element, 32 Upper arm diode, 33 Lower arm switching element, 34 Lower arm diode, 41, 48, 54 I / O line, 43, 44 connection point, 45 High voltage I / O line, 46, 52 Reference I / O line, 47 Low voltage I / O line, 42, 49, 55 Negative I / O line, 51 Secondary input Output line, 53a Connection line, 53 Primary side input / output line, 56 Positive side charging line, 57 Negative side charging line, 58, 59 Charging terminal, 60 External power input switch, 61, 63, 65, 68 Voltage sensor, 62, 64 current sensor, 70 external power source, 71, 72 charging plug, 80 control unit, 100 power supply device.

Claims (2)

A first power storage device to which a first input / output line for inputting and outputting power is connected;
A second power storage device to which a second input / output line for inputting / outputting electric power is connected,
The first power storage device and the second power storage device are connected in parallel via the first and second input / output lines,
The power supply device including a voltage converter provided between the connection point between the first input output line and the second input output line and said second power storage device,
The second power storage device includes a charging terminal connected to an external power source ,
An on / off switch is provided between the second power storage device and the charging terminal;
The voltage converter includes a plurality of switching elements,
A control unit for turning on and off each of the switching elements and the on / off switch;
The controller is
First charging means for turning on and off the switching element of the voltage converter and charging the second power storage device to substantially the same voltage as the external power source by the power of the first power storage device;
External power connection means for charging the second power storage device by the first charging means and then turning on the on / off switch to connect the external power source and the second power storage device ;
A power supply device comprising: The power supply device according to claim 1 ,
The controller is
After connecting the external power supply and the second power storage device by the external power supply connection means, the switching device of the voltage converter is turned on and off to charge the first power storage device with the power of the external power supply Having a charging means of
A power supply characterized by.

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