JP6477342B2 - Automobile - Google Patents

Description

  The technology disclosed in the present specification relates to an automobile having a main battery and a sub battery having a lower voltage than the main battery.

  In Patent Document 1, a main battery, a power control unit that controls power supplied from the main battery to supply power to a traveling motor, a sub battery having a lower voltage than the main battery, and a sub battery are supplied. A hybrid vehicle is disclosed that includes a switch that switches between conduction and non-conduction of the main power supply wiring between the main battery and the power control unit using electric power, and a plurality of auxiliary machines that are operated by electric power supplied from the sub-battery. . In this hybrid vehicle, when the system is started, before the switch switches the main power supply wiring from non-conduction to conduction, the power is supplied from the sub-battery to the multiple auxiliary machines to perform initial operations on the multiple auxiliary machines. Let When the sub-battery voltage at the time of system startup is lower than a predetermined value, a time difference is provided in the timing of the initial operation of the plurality of auxiliary devices to cause the plurality of auxiliary devices to execute the initial operation. As a result, the sub-battery can supply power for initial operation to a plurality of auxiliary machines at different timings, so that the system can be started even in a situation where the sub-battery voltage is lowered. .

JP 2013-159158 A

  When the sub-battery voltage at the time of starting the system is very low, the switch cannot be switched by the power from the sub-battery, and the main battery and the power control unit may not be conducted. In this case, the system cannot be activated even by the above technique.

  The present specification discloses a technique for dealing with a case where the switch cannot be switched by power from the sub battery because the sub battery voltage is very low.

The automobile disclosed in this specification includes a main battery, a main power supply wiring connected to the main battery, and a power that includes a smoothing capacitor connected to the main power supply wiring and smoothing the voltage of the main power supply wiring. The control unit, the sub-battery having a voltage lower than that of the main battery, the sub power wiring connected to the sub battery, and the main power wiring between the main battery and the power control unit using the power supplied from the sub battery. A switch that switches between conduction and non-conduction, and a plurality of auxiliary machines that operate with electric power supplied from the sub-battery are provided. Furthermore, a transformer including a first coil, a second coil, and a third coil, a main circuit on the main battery side of the switch and the first circuit connecting the first coil, and a main power source on the power control unit side of the switch A second circuit for connecting the wiring and the second coil, and a third circuit for connecting the sub power supply wiring and the third coil are provided.

The first circuit has a function of a DC-AC converter, the second circuit has a function of an AC-DC converter, and the third circuit has a function of an AC-DC converter. When the first circuit operates, the current converted from DC to AC flows to the first coil, and the first coil becomes the primary coil of the transformer. In that case, the second coil and the third coil become secondary coils of the transformer, and an AC current is generated in the secondary coil. This AC current is converted to DC by the third circuit and supplied to the sub power supply wiring. One of the plurality of auxiliary machines is a control device, and the control device operates with electric power supplied from the sub-battery. The control device is set to execute the following control procedure. That is, the first circuit is operated before the main power supply wiring is switched from non-conduction to conduction by the switch. Then, the supply process for supplying power from the main battery to the sub power supply wiring via the transformer starts. Then, electric power is supplied from the sub battery to the auxiliary equipment which is not involved in the operation of the first circuit of the plurality of auxiliary devices. At the same time, during the operation of the first circuit, precharging is performed to supply power from the main battery to the smoothing capacitor via the transformer and the second circuit. After completion of the precharge, a processing procedure for switching the main power supply wiring from non-conductive to conductive is performed by switching the switch.

  In the above automobile, before the main power supply wiring is switched from non-conduction to conduction by the switch, the first circuit is operated to start supplying power from the main battery to the sub power supply wiring. Then change the switch. When switching the switch, even if the power is already supplied from the main battery to the sub power supply wiring and the switch cannot be switched by the power from the sub battery before the supply process is started, the switch can be switched. it can. In this configuration, the control device and the first circuit need to be able to operate with the power supplied by the sub-battery before the supply process is started. On the other hand, before the supply process is started, it is not necessary to supply power to the auxiliary machines that are not involved in the operation of the first circuit among the plurality of auxiliary machines. For this reason, the switch can be switched even in a situation where the sub-battery voltage is very low before the supply process is started.

  Details and further improvements of the technology disclosed in this specification will be described in detail in the section of Detailed Description.

It is a block diagram of the electric system of the motor vehicle of an Example. It is a figure which shows the schematic structure of the 1st circuit of an Example, a 2nd circuit, and a 3rd circuit. It is a flowchart which shows the starting process for starting the power supply system of an Example.

  The hybrid vehicle 2 of this embodiment shown in FIG. 1 can travel using the power of the main battery 4, and can also travel using the engine 100. When traveling using the power of the main battery 4, the hybrid vehicle 2 drives the second motor 8 with the power supplied from the main battery 4, and drives driving wheels (not shown) with the power of the second motor 8. Rotate. When traveling using the engine 100, the hybrid vehicle 2 starts the engine 100 using the first motor 6 as a cell motor. The hybrid vehicle 2 transmits a part of the power generated by the engine 100 to the drive wheels by the power split mechanism 102 while transmitting the remainder of the power of the engine 100 to the first motor 6. 6 to generate electricity. The electric power generated by the first motor 6 can be supplied to the second motor 8 and used to rotate the drive wheels, or the main battery 4 and the sub-battery 22 can be charged. It is also possible to supply power to the second motor 8 from the main battery 4 and rotate the drive wheels while traveling using the engine 100. When the traveling hybrid vehicle 2 decelerates, the regenerative power generation can be performed by the second motor 8 and the power generated by the second motor 8 can be charged to the main battery 4.

  The hybrid vehicle 2 includes a power supply system 1 and a plurality of auxiliary machines 26 in addition to the motors 6 and 8, the engine 100, and the power split mechanism 102. The power supply system 1 includes a main battery 4, a sub battery 22, a power control unit (PCU) 12, a first circuit 28, a second circuit 30, a third circuit 32, a transformer 36, and a main power supply wiring 10. The sub power supply wiring 24 is provided. The main battery 4 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. In this embodiment, the voltage of the main battery 4 is about 300V. The voltage of the main battery 4 is measured by the voltage sensor 50. The hybrid vehicle 2 can generate power with the first motor 6 using the power of the engine 100 and charge the main battery 4 with the power generated by the first motor 6. Further, when the traveling hybrid vehicle 2 decelerates, regenerative power generation can be performed by the second motor 8, and the electric power generated by the second motor 8 can be charged to the main battery 4.

  The main battery 4 is connected to the PCU 12 via the main power supply wiring 10. The main power supply wiring 10 includes a positive line 10 a connected to the positive terminal of the main battery 4 and a negative line 10 b connected to the negative terminal of the main battery 4.

  The PCU 12 is provided between the main battery 4 and the first motor 6 and the second motor 8. The PCU 12 includes a smoothing capacitor 14, a converter 16, and an inverter 18. The smoothing capacitor 14 smoothes the voltage of the main power supply wiring 10. The voltage of the smoothing capacitor 14 is measured by the voltage sensor 53. The converter 16 boosts the voltage of the power supplied from the main battery 4 to a voltage suitable for driving the first motor 6 and the second motor 8 as necessary. Converter 16 can also step down the voltage of the power generated by first motor 6 or second motor 8 to a voltage suitable for charging main battery 4. In this embodiment, the voltage used to drive the first motor 6 and the second motor 8 is about 600V. The inverter 18 converts the DC power supplied from the main battery 4 into three-phase AC power for driving the first motor 6 and the second motor 8. The inverter 18 can also convert the three-phase AC power generated by the first motor 6 and the second motor 8 into DC power for charging the main battery 4.

  A system main relay (SMR) 20 is provided between the main battery 4 and the PCU 12. The SMR 20 includes a switch 20a that switches between conduction and non-conduction of the positive electrode line 10a of the main power supply wiring 10, and a switch 20b that switches between conduction and non-conduction of the negative electrode line 10b of the main power supply wiring 10. That is, the SMR 20 switches between conduction and non-conduction of the main power supply wiring 10 by switching on and off of the switches 20 a and 20 b using the power supplied from the sub-battery 22.

  The hybrid vehicle 2 includes a sub battery 22 having a lower voltage than the main battery 4. The sub battery 22 is a secondary battery such as a lead battery. In the present embodiment, the voltage of the sub-battery 22 is about 13V to 14.5V. The voltage of the sub battery 22 is measured by the voltage sensor 54. The current value of the sub power supply wiring 24 is measured by the current sensor 52.

  The sub-battery 22 is connected to a plurality of auxiliary machines 26 through a sub power supply wiring 24. The sub battery 22 supplies power to each of the plurality of auxiliary machines 26. The plurality of auxiliary machines 26 includes an electronic control unit (ECU) 60, an air conditioner (not shown), a navigation device, a power steering, an audio device, a seat heater, a lighting device such as a headlamp and a room lamp, and the like. The ECU 60 includes a CPU and a memory. ECU 60 is connected to a plurality of auxiliary machines 26 other than power supply system 1 and ECU 60 and controls a plurality of auxiliary machines 26 other than power supply system 1 and ECU 60 in accordance with a program stored in a memory.

  A first circuit 28 is connected between the main power supply wiring 10 on the main battery 4 side of the SMR 20 and the first coil 36 c of the transformer 36. As will be described in detail later, the transformer 36 includes a second coil 36a and a third coil 36b in addition to the first coil 36c. The second circuit 30 is connected between the main power supply wiring 10 closer to the PCU 12 than the SMR 20 and the second coil 36a. The third circuit 32 is connected between the sub power supply wiring 24 and the third coil 36b. The main power supply wiring 10 closer to the main battery 4 than the SMR 20 is connected to the sub power supply wiring 24 via the first circuit 28, the transformer 36 and the third circuit 32. The combination of the first circuit 28, the transformer 36, and the third circuit 32 can perform a step-down operation for supplying power by stepping down from the main power supply wiring 10 to the sub power supply wiring 24, or from the sub power supply wiring 24 to the main power supply wiring. It is also possible to perform a boosting operation that boosts the voltage to 10 and supplies power. The combination of the first circuit 28, the transformer 36, and the third circuit 32 is a so-called bidirectional DC-DC converter, and can be called a step-up / step-down DC-DC converter. Note that the combination of the first circuit 28, the transformer 36, and the third circuit 32 may not perform the boosting operation of boosting power from the sub power supply wiring 24 to the main power supply wiring 10 and supplying power.

  The main power supply wiring 10 and the sub power supply wiring 24 closer to the PCU 12 than the SMR 20 are connected via the second circuit 30, the transformer 36, and the third circuit 32. The combination of the second circuit 30, the transformer 36, and the third circuit 32 can perform a step-down operation for supplying power by stepping down from the main power supply wiring 10 on the PCU 12 side to the sub power supply wiring 24 with respect to the SMR 20. It is also possible to perform a boosting operation for boosting power from the wiring 24 to the main power supply wiring 10 on the PCU 12 side of the SMR 20 and supplying power. That is, the combination of the second circuit 30, the transformer 36, and the third circuit 32 is a so-called bidirectional DC-DC converter, and can be called a step-up / step-down DC-DC converter.

  Further, the main power supply wiring 10 on the main battery 4 side of the SMR 20 and the main power supply wiring 10 on the PCU 12 side of the SMR 20 are connected via the first circuit 28, the transformer 36, and the second circuit 30. The combination of the first circuit 28, the transformer 36, and the second circuit 30 may perform a supply operation of supplying power from the main power supply wiring 10 on the main battery 4 side of the SMR 20 to the main power supply wiring 10 on the PCU 12 side of the SMR 20. In addition, a supply operation of supplying power from the main power supply wiring 10 on the PCU 12 side of the SMR 20 to the main power supply wiring 10 on the main battery 4 side of the SMR 20 can be performed. The combination of the first circuit 28, the transformer 36, and the second circuit 30 performs a supply operation for supplying power from the main power supply wiring 10 on the PCU 12 side of the SMR 20 to the main power supply wiring 10 on the main battery 4 side of the SMR 20. It does not have to be.

  In the power supply system 1, the first circuit 28, the second circuit 30, and the third circuit 32 operate, so that power can be exchanged between the main power supply wiring 10 and the sub power supply wiring 24 regardless of the conduction / non-conduction of the SMR 20. I can meet each other. Specifically, the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs a step-down operation, so that the electric power generated by the first motor 6 and the second motor 8 can be charged to the sub-battery 22. . Further, the combination of the second circuit 30, the transformer 36 and the third circuit 32 performs the boosting operation, so that the first motor 6 and the second motor 8 can be driven using the power of the sub-battery 22. Further, the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs a step-down operation, so that the power from the main battery 4 can be charged to the sub-battery 22. Further, the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the boosting operation, whereby the power from the sub battery 22 can be charged to the main battery 4. Further, even if the SMR 20 is non-conductive, the combination of the first circuit 28, the transformer 36, and the second circuit 30 performs the supply operation, so that the power from the main battery 4 is transferred to the PCU 12 without passing through the sub power supply wiring 24. The main battery 4 can be charged with the electric power generated by the first motor 6 and the second motor 8.

  FIG. 2 shows a schematic configuration of the first to third circuits 28, 30 and 32 and the transformer 36. The first to third circuits 28, 30, 32 and the transformer 36 are accommodated in one housing 58. The first circuit 28 is connected to the main power supply wiring 10 through the connection wiring 78.

  The first circuit 28 includes a filter 44, a switching circuit 46, and a backflow prevention switch 45. The filter 44 includes a capacitor 44a. The filter 44 suppresses the generation of noise on the main power supply wiring 10 side. The backflow prevention switch 45 is capable of supplying power from the first circuit 28 to the main power supply wiring 10 on the main battery 4 side by switching on and off of the switching element (that is, the switching element is on) and impossible. (Ie, the switching element is turned off).

  The switching circuit 46 includes switching elements 46a, 46b, 46c, and 46d and free-wheeling diodes 46e, 46f, 46g, and 46h connected in parallel to the respective switching elements 46a, 46b, 46c, and 46d. The switching element 46a and the switching element 46b are connected in series, and the switching element 46c and the switching element 46d are connected in series.

  The switching circuit 46 is connected to the transformer 36. The transformer 36 includes three coils 36a, 36b, and 36c. The first coil 36 c is connected to the switching circuit 46 via the connection wiring 76. That is, the first circuit 28 connects the main power supply wiring 10 closer to the main battery 4 than the SMR 20 and the first coil 36c. The second coil 36 a is connected to the switching circuit 34 of the second circuit 30 through the connection wiring 72. The third coil 36 b is connected to the switching circuit 38 of the third circuit 32 through the connection wiring 74. The transformer 36 can supply power by stepping down from the second coil 36a to the third coil 36b, or can supply power by stepping up from the third coil 36b to the second coil 36a. Further, in the transformer 36, power can be supplied by stepping down from the first coil 36c to the third coil 36b, or power can be supplied by stepping up from the third coil 36b to the first coil 36c. In addition, power can be supplied from the first coil 36c to the second coil 36a without changing the voltage, or power can be supplied from the second coil 36a to the first coil 36c without changing voltage. .

  One end of the first coil 36 c is connected between the switching element 46 a and the switching element 46 b via the connection wiring 76, and the other end of the first coil 36 c is connected to the switching element 46 c and the switching element via the connection wiring 76. 46d is connected.

  In the switching circuit 46, each of the switching elements 46a, 46b, 46c, and 46d is switched on and off at a predetermined timing, thereby converting DC power supplied from the main power supply wiring 10 to the switching circuit 46 into AC power. That is, the switching circuit 46 functions as a DC-AC converter. In the switching circuit 46, the AC power supplied from the transformer 36 is converted into DC power by the diodes 46e, 46f, 46g, and 46h. That is, the switching circuit 46 also functions as an AC-DC converter (that is, a rectifier).

  The first circuit 28 is controlled by the control circuit 43. Specifically, the control circuit 43 controls the operations of the switching elements 46 a, 46 b, 46 c, 46 d and the backflow prevention switch 45 of the switching circuit 46.

  The second circuit 30 connected to the second coil 36 a is connected to the main power supply wiring 10 via the connection wiring 70. That is, the second circuit 30 connects the main power supply wiring 10 closer to the PCU 12 than the SMR 20 and the second coil 36a. The second circuit 30 includes a filter 33, a switching circuit 34, and a backflow prevention switch 31. The filter 33 includes a capacitor 33a. The filter 33 suppresses the generation of noise on the main power supply wiring 10 side. The backflow prevention switch 31 is in a state in which power can be supplied from the second circuit 30 to the main power supply wiring 10 on the PCU 12 side (that is, in a state in which the switching element is on) and in an impossible state by switching the switching element on and off. (That is, the switching element is off).

  The switching circuit 34 includes switching elements 34a, 34b, 34c, 34d and free-wheeling diodes 34e, 34f, 34g, 34h connected in parallel to the respective switching elements 34a, 34b, 34c, 34d. The switching element 34a and the switching element 34b are connected in series, and the switching element 34c and the switching element 34d are connected in series. One end of the second coil 36 a is connected between the switching element 34 a and the switching element 34 b via the connection wiring 72, and the other end of the second coil 36 a is connected to the switching element 34 c and the switching element via the connection wiring 72. 34d.

  In the switching circuit 34, each of the switching elements 34a, 34b, 34c, and 34d is switched on and off at a predetermined timing, thereby converting DC power supplied from the main power supply wiring 10 to the switching circuit 34 into AC power. That is, the switching circuit 34 functions as a DC-AC converter. In the switching circuit 34, the AC power supplied from the transformer 36 is converted into DC power by the diodes 34e, 34f, 34g, and 34h. That is, the switching circuit 34 also functions as an AC-DC converter (that is, a rectifier).

  The third circuit 32 connected to the third coil 36 b is connected to the sub power supply wiring 24. That is, the second circuit 32 connects the sub power supply wiring 24 and the third coil 36b. The third circuit 32 includes a filter 40, a switching circuit 38, and a backflow prevention switch 41. The filter 40 includes an inductor 40a and a capacitor 40b. The filter 40 suppresses the generation of noise on the sub power supply wiring 24 side. The backflow prevention switch 41 switches between turning on and off of the switching element, whereby the power can be supplied from the third circuit 32 to the sub power supply wiring 24 (that is, the switching element is on) and the state that is not possible (that is, switching) Switch the element off).

  The switching circuit 38 includes switching elements 38a, 38b, 38c, 38d, free-wheeling diodes 38e, 38f, 38g, 38h connected in parallel to the respective switching elements 38a, 38b, 38c, 38d, an inductor 38i, and a capacitor 38j. It has. The switching element 38a and the switching element 38b are connected in series, and the switching element 38c and the switching element 38d are connected in series. One end of the third coil 36 b is connected between the switching element 38 a and the switching element 38 b via the connection wiring 74, and the other end of the third coil 36 b is connected to the switching element 38 c and the switching element via the connection wiring 74. 38d.

  In the switching circuit 38, each of the switching elements 38a, 38b, 38c, and 38d is switched on and off at a predetermined timing, thereby converting DC power supplied from the sub power supply wiring 24 to the switching circuit 38 into AC power. That is, the switching circuit 38 functions as a DC-AC converter. In the switching circuit 38, the AC power supplied from the transformer 36 is converted into DC power by the diodes 38e, 38f, 38g, and 38h. That is, the switching circuit 38 also functions as an AC-DC converter (that is, a rectifier).

  The second circuit 30 and the third circuit 32 are controlled by the control circuit 42. Specifically, the control circuit 42 includes the switching elements 34a, 34b, 34c, 34d and the backflow prevention switch 31 of the switching circuit 34 of the second circuit 30, and the switching elements 38a, 38b of the switching circuit 38 of the third circuit 32. The operations of 38c and 38d and the backflow prevention switch 41 are controlled.

  Next, operations of the first to third circuits 28, 30, and 32 will be described. First, the case where the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs the step-down operation by the operation of the second circuit 30 and the third circuit 32 will be described. When the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs a step-down operation, the switching elements 34a, 34b, 34c, 34d operate in the switching circuit 34 of the second circuit 30, and the DC-AC By functioning as a converter, the DC power supplied from the main power supply wiring 10 is converted into AC power. Then, the converted AC voltage is stepped down by the transformer 36, and the switching circuit 38 of the third circuit 32 functions as an AC-DC converter, thereby converting AC power into DC power. In this case, in the switching circuit 38, rectification by the freewheeling diodes 38e, 38f, 38g, and 38h and smoothing by the inductor 38i and the capacitor 38j are performed. As a result, power can be supplied by stepping down from the main power supply wiring 10 to the sub power supply wiring 24. When the switching circuit 38 functions as an AC-DC converter, each of the switching elements 38a, 38b, 38c, 38d is turned on while a current flows through the free-wheeling diodes 38e, 38f, 38g, 38h connected in parallel. Is done. Thereby, the electric current which flows into free-wheeling diode 38e, 38f, 38g, 38h can be reduced.

  Next, a case where the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs the boosting operation by the operation of the second circuit 30 and the third circuit 32 will be described. When the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs the boosting operation, the switching elements 38a, 38b, 38c, 38d operate in the switching circuit 38 of the third circuit 32, and the DC-AC By functioning as a converter, the DC power supplied from the sub power supply wiring 24 is converted into AC power. The converted AC voltage is boosted by the transformer 36, and the switching circuit 34 of the second circuit 30 functions as an AC-DC converter, thereby converting AC power into DC power. In this case, in the switching circuit 34, rectification is performed by the free-wheeling diodes 34e, 34f, 34g, and 34h, and smoothing is performed in the filter 33. As a result, power can be supplied from the sub power supply wiring 24 to the main power supply wiring 10 while being boosted. When the switching circuit 34 functions as an AC-DC converter, each of the switching elements 34a, 34b, 34c, 34d is turned on while a current flows through the free-wheeling diodes 34e, 34f, 34g, 34h connected in parallel. Is done. Thereby, the electric current which flows into free-wheeling diode 34e, 34f, 34g, 34h can be reduced.

  During the step-up / step-down operation of the combination of the second circuit 30, the transformer 36 and the third circuit 32, the backflow prevention switch 45 of the first circuit 28 cannot be supplied from the first circuit 28 to the main power supply wiring 10 on the main battery 4 side. By maintaining this state, power can be prevented from being unintentionally supplied to the main power supply wiring 10 on the main battery 4 side.

  Next, the case where the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the step-down operation by the operation of the first circuit 28 and the third circuit 32 will be described. When the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the step-down operation, the switching elements 46a, 46b, 46c, 46d operate in the switching circuit 46 of the first circuit 28, and the DC-AC By functioning as a converter, the DC power supplied from the main power supply wiring 10 is converted into AC power. Then, the converted AC voltage is stepped down by the transformer 36, and the switching circuit 38 of the third circuit 32 functions as an AC-DC converter, thereby converting AC power into DC power. In this case, the switching circuit 38 operates in the same manner as when the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs the step-down operation. As a result, power can be supplied by stepping down from the main power supply wiring 10 to the sub power supply wiring 24.

  Next, the case where the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the boosting operation by the operation of the first circuit 28 and the third circuit 32 will be described. When the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the boosting operation, the switching circuit 38 of the third circuit 32 is a combination of the second circuit 30, the transformer 36, and the third circuit 32. As in the case of the step-up operation, the DC power supplied from the sub power supply wiring 24 is converted into AC power by functioning as a DC-AC converter. The converted AC voltage is boosted by the transformer 36, and the switching circuit 46 of the first circuit 28 functions as an AC-DC converter, thereby converting AC power into DC power. In this case, in the switching circuit 46, rectification is performed by the freewheeling diodes 46e, 46f, 46g, and 46h, and smoothing is performed in the filter 44. As a result, power can be supplied from the sub power supply wiring 24 to the main power supply wiring 10 while being boosted. When the switching circuit 46 functions as an AC-DC converter, each of the switching elements 46a, 46b, 46c, 46d is turned on while a current flows through the free-wheeling diodes 46e, 46f, 46g, 46h connected in parallel. Is done. Thereby, the electric current which flows into the free-wheeling diodes 46e, 46f, 46g, and 46h can be reduced.

  During the step-up / step-down operation of the combination of the first circuit 28, the transformer 36, and the third circuit 32, the backflow prevention switch 31 of the second circuit 30 cannot be supplied from the second circuit 30 to the main power supply wiring 10 on the PCU 12 side. By keeping the power on, power can be prevented from being unintentionally supplied to the main power supply wiring 10 on the PCU 12 side.

  Next, the case where the combination of the first circuit 28, the transformer 36, and the second circuit 30 performs the supply operation by the operation of the first circuit 28 and the second circuit 30 will be described. When the combination of the first circuit 28, the transformer 36, and the second circuit 30 performs the supply operation, the switching circuit 46 of the first circuit 28 is a combination of the first circuit 28, the transformer 36, and the third circuit 32. As in the case of performing the step-down operation, the DC power supply functions as a DC-AC converter, thereby converting the DC power supplied from the main power supply wiring 10 into AC power. Then, the converted AC voltage is converted from AC power to DC power in the switching circuit 34 of the second circuit 30 without changing the voltage in the transformer 36. In this case, the switching circuit 34 functions as an AC-DC converter so that the combination of the second circuit 30, the transformer 36, and the third circuit 32 performs a boosting operation. Convert to. As a result, power is supplied from the main power supply wiring 10 on the main battery 4 side of the SMR 20 to the main power supply wiring 10 on the PCU 12 side of the SMR 20 without changing the voltage while the SMR 20 maintains the main power supply wiring 10 in the non-conductive state. can do.

  Further, when the combination of the first circuit 28, the transformer 36, and the second circuit 30 performs the supply operation, the switching circuit 34 of the second circuit 30 is connected to the second circuit 30, the transformer 36, and the third circuit 32. As in the case where the combination performs a step-down operation, the DC power supplied from the main power supply wiring 10 is converted into AC power by functioning as a DC-AC converter. The converted AC voltage is converted from AC power to DC power in the switching circuit 46 of the first circuit 28 without changing the voltage in the transformer 36. In this case, the switching circuit 46 functions as an AC-DC converter so that the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs a step-up operation. Convert to. As a result, the SMR 20 supplies power without changing the voltage from the main power supply wiring 10 on the PCU 12 side of the SMR 20 to the main power supply wiring 10 on the main battery 4 side of the SMR 20 with the main power supply wiring 10 kept non-conductive. can do.

  During this supply operation, power is unintentionally supplied to the sub power supply wiring 24 by maintaining the backflow prevention switch 41 of the third circuit 32 in a state in which it cannot be supplied from the third circuit 32 to the sub power supply wiring 24. Can be prevented.

  Through the operations of the first to third circuits 28, 30, and 32 described above, power can be interchanged between the main power supply wiring 10 on the main battery 4 side, the main power supply wiring 10 on the PCU 12 side, and the sub power supply wiring 24. it can. As a result, the electric power stored in the vehicle can be used effectively.

  The specific circuit configuration of the first to third circuits 28, 30, and 32 shown in FIG. 2 is merely an example, and in the second circuit 30 and the third circuit 32, the voltage is stepped down from the main power supply wiring 10 to the sub power supply wiring 24. As long as the step-down operation for supplying power and the step-up operation for boosting power from the sub power supply wiring 24 to the main power supply wiring 10 are possible, any configuration may be used. Similarly, the first circuit 28 is configured to step down from the main power supply wiring 10 to the sub power supply wiring 24 and supply power, and from the main power supply wiring 10 on the main battery 4 side of the SMR 20 to the PCU 12 side of the SMR 20 side. Any configuration may be used as long as the supply operation to the main power supply wiring 10 is possible. The control circuits 42 and 43 are controlled by the ECU 60.

  In the hybrid vehicle 2, when the driver switches the ignition switch from off to on, for example, the power supply system 1 is activated. With reference to FIG. 3, the starting process for starting the power supply system 1 performed with the hybrid vehicle 2 is demonstrated.

  In the activation process, first, in S12, only the ECU 60 among the plurality of auxiliary machines 26 is activated in the hybrid vehicle 2. On the other hand, the plurality of auxiliary machines 26 other than the ECU 60 are not activated. Next, in S14, the ECU 60 activated in S12 causes the control circuits 42 and 43 to execute the first circuit 28 and the first circuit so that the combination of the first circuit 28, the transformer 36, and the third circuit 32 performs the step-down operation. 3. Sends an instruction to activate the circuit 30. As a result, the combination of the first circuit 28, the transformer 36, and the third circuit 32 starts the step-down operation, so that the main battery 4 is transferred from the main battery 4 to the sub battery 22 while the SMR 20 maintains the main power supply wiring 10 in the non-conductive state. Power supply is started. In this step-down operation, the switching circuit 46 of the first circuit 28 functions as a DC-AC converter, and the switching circuit 38 of the third circuit 32 functions as an AC-DC converter. The ECU 60 further transmits to the control circuits 42 and 43 instructions for turning off the backflow prevention switches 45 and 31 and turning on the backflow prevention switch 41.

  Next, in S <b> 16, the ECU 60 transmits an instruction for operating the second circuit to the control circuit 42 so that the combination of the first circuit 28, the transformer 36, and the second circuit 30 performs the supply operation. The first circuit 28 is operated in S14 and is operating as a DC-AC converter. As a result, the combination of the first circuit 28, the transformer 36, and the second circuit 30 starts the supply operation, so that the power from the main battery 4 to the PCU 12 is maintained while the SMR 20 keeps the main power supply wiring 10 non-conductive. Supply is started. The ECU 60 further transmits an instruction for turning on the backflow prevention switch 31 to the control circuit 42.

  When the SMR 20 is switched from non-conductive to conductive, if the voltage of the main battery 4 is different from the voltage of the smoothing capacitor 14 of the PCU 12, a large inrush current is generated in the main power supply wiring 10 immediately after the SMR 20 is switched to conductive. Flowing. In the hybrid vehicle 2, before the SMR 20 is switched from non-conduction to conduction, the smoothing capacitor 14 is precharged in order to make the voltage of the main battery 4 coincide with the voltage of the smoothing capacitor 14.

  In S18, the ECU 60 determines that the difference (VB−VL) between the voltage VB of the main battery 4 measured by the voltage sensor 50 and the voltage VL of the smoothing capacitor 14 measured by the voltage sensor 56 is equal to or less than a predetermined potential difference Vz. Judge whether there is. The predetermined potential difference Vz is caused by welding of the contacts of the switches 20a and 20b of the SMR 20 due to an inrush current flowing from the main battery 4 to the smoothing capacitor 14 immediately after the SMR 20 is switched from non-conduction to conduction, The voltage difference is such that the function is not disabled.

  If the difference (VB−VL) between the voltage VB of the main battery 4 and the voltage VL of the smoothing capacitor 14 is not equal to or less than the predetermined potential difference Vz (NO in S18), the difference between the voltage VB and the voltage VL of the smoothing capacitor 14 The process of S18 is repeatedly executed until (VB−VL) becomes equal to or less than the predetermined potential difference Vz. This prevents a problem from occurring in the switches 20a and 20b of the SMR 20 due to an inrush current flowing from the main battery 4 to the smoothing capacitor 14 immediately after the SMR 20 is switched from non-conduction to conduction. On the other hand, if it is equal to or less than the predetermined potential difference Vz (YES in S18), in S20, the ECU 60 stops the operation of the first to third circuits 28, 30, 32, and turns the backflow prevention switches 31, 41, 45 on. A signal for turning off is transmitted to the control circuits 42 and 43, and charging and precharging of the sub-battery 22 are terminated.

  Next, in S22, the ECU 60 switches the SMR 20 from non-conduction to conduction. As a result, power can be supplied from the main battery 4 to the PCU 12 via the SMR 20. Thus, the motors 6 and 8 can be driven using the power of the main battery 4. At the time when the main power supply wiring 10 switches from non-conduction to conduction, the precharge has already been completed. For this reason, a large inrush current does not flow from the main battery 4 to the smoothing capacitor 14 when the SMR 20 is switched from non-conduction to conduction. Note that when the SMR 20 is switched from non-conduction to conduction, the operations of the first to third circuits 28, 30, and 32 do not have to be stopped. That is, the process of S20 may be executed after the process of S22. In this configuration, while power is being supplied from the main battery 4 to the sub power supply wiring 24, the SMR 20 is switched from non-conduction to conduction, and the power supplied to the sub power supply wiring 24 is used to make the SMR 20 non-conductive. May be switched from continuity to conduction.

  Next, in S24, the ECU 60 operates an auxiliary machine other than the ECU 60 among the plurality of auxiliary machines 26. Auxiliary machines other than the ECU 60 operate with electric power supplied from the sub-battery 22. The sub-battery 22 is charged with the electric power from the main battery 4 at the timing when electric power is supplied to the auxiliary machines other than the ECU 60. For this reason, it is possible to avoid a situation in which the auxiliary battery cannot operate due to insufficient power of the sub-battery 22.

  In the above configuration, before the main power supply wiring 10 is switched from non-conduction to conduction by the SMR 20, only the ECU 60 among the plurality of auxiliary machines 26 is activated. Then, the ECU 60 performs a step-down operation on the combination of the first circuit 28, the transformer 36, and the third circuit 32, so that electric power is supplied from the main battery 4 to the sub battery 22 before switching from non-conduction to conduction by the SMR 20. Can be supplied. For this reason, before the start-up process of FIG. 3 is executed, even if the amount of charging power is so low that the sub-battery 22 cannot supply the power necessary for switching the SMR 20 from the non-conductive state to the conductive state, As long as the amount of electric power is sufficient to execute the step-down operation of the combination of the first circuit 28, the transformer 36, and the third circuit 32, it is sufficient. As a result, the power necessary for the SMR 20 can be supplied at the timing when the sub-battery 22 should supply the power to the SMR 20 in S22. In the starting process of FIG. 3, before executing S20, the ECU 60 determines whether or not the voltage of the sub-battery 22, that is, the voltage VS of the voltage sensor 54 is equal to or higher than a predetermined value, and the voltage VS is equal to or higher than the predetermined value. In some cases, the process may proceed to S20.

  In the precharge in S16 and S18, power is supplied from the main battery 4 to the PCU 12. According to this configuration, it is not necessary to supply power from the sub-battery 22 to the PCU 12, and it is possible to prevent the charging power amount of the sub-battery 22 from being reduced by precharging.

  The configurations of the first to third circuits 28, 30, and 32 are not limited to the configurations of the above-described embodiments. For example, when adopting a configuration in which power is not supplied from the sub power supply wiring 24, the third circuit 32 may not include the switching elements 38a to 38d. That is, the third circuit 32 functions as an AC-DC converter, but may not function as a DC-AC converter.

  Furthermore, when adopting a configuration in which power is not supplied from the main power supply wiring 10 on the PCU 12 side, the second circuit 30 may not include the switching elements 34a to 34d. That is, the second circuit 30 functions as an AC-DC converter, but may not function as a DC-AC converter.

  When adopting a configuration in which power is not supplied to the main power supply wiring 10 on the main battery 4 side, the first circuit 28 may function as a DC-AC converter, but may not function as an AC-DC converter.

  It is sufficient that at least the first circuit 28 has a DC-AC converter function and the third circuit 32 has an AC-DC converter function.

  The ECU 60 may include one CPU and one memory, may include a plurality of CPUs, and may include a plurality of memories. Moreover, ECU60 may be comprised so that several ECU may be arrange | positioned separately. For example, the ECU 60 includes a plurality of ECUs including a first ECU and a second ECU, the first ECU controls the first to third circuits 28, 30, and 32, and the second ECU is other than the ECU 60. When controlling the auxiliary machine of FIG. 3, in S12 of FIG. 3, it is not necessary to start the first ECU and start the second ECU. When the ECU 60 includes a plurality of ECUs, in S12 of FIG. 3, an ECU necessary for executing S14 to S22, that is, an ECU for operating the first to third circuits 28, 30, and 32, and a voltage sensor The ECU that acquires the voltages VB and VL from 50 and 53 and the ECU that controls the SMR may be activated, and the other ECUs may not be activated.

  In S12 of FIG. 3, only the ECU 60 is activated, but at least one of the plurality of auxiliary machines 26 other than the ECU 60 may be activated before the process of S22. For example, the instrument panel of the hybrid vehicle 2 may be operated to indicate that the power supply system 1 is being activated. Or you may operate the auxiliary machine with low electric power required for operation | movement. In this case, at least one auxiliary machine (for example, an auxiliary machine having a high power required for operation) may not be activated before the process of S22.

  At least one of the backflow prevention switches 31, 41, 45 may be a cut-off switch that cuts off power so that power is not supplied between the corresponding coil and the corresponding power supply wiring. For example, when the backflow prevention switch 31 is replaced with a cutoff switch, when the cutoff switch is on, power can be supplied between the second coil 36a and the main power supply wiring 10 on the PCU 12 side, while the cutoff switch is off. In this case, it may be impossible to supply power between the second coil 36a and the main power supply wiring 10 on the PCU 12 side.

  When the switching circuits 34, 38, 46 function as an AC-DC converter, the switching elements 34a, 34b, 34c, 34d, 38a, 38b, 38c, 38d, 46a, 46b included in the switching circuits 34, 38, 46 are used. , 46c, 46d may be kept off (i.e., non-conducting) without operating.

  In the above embodiment, the hybrid vehicle 2 is an example of “automobile”. However, the “automobile” may be an electric vehicle provided with only a motor for driving without an engine.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

  In some embodiments, the power control unit may include a smoothing capacitor that smoothes the voltage of the main power supply wiring. The second circuit may have the function of an AC-DC converter. During operation of the first circuit, precharge is performed to supply power from the main battery to the smoothing capacitor via the transformer and the second circuit, and after the precharge is completed, the switch is switched to switch the main power supply wiring from the non-conductive state to the conductive state. A processing procedure for switching to may be executed. According to this configuration, the difference between the voltage of the main battery and the voltage of the smoothing capacitor immediately after switching the switch from non-conduction to conduction by supplying power from the main battery to the power control unit and precharging the smoothing capacitor. Therefore, it is possible to prevent a large inrush current from flowing through the main power supply wiring.

1: Power supply system 2: Hybrid vehicle 4: Main battery 10: Main power supply wiring 12: PCU
14: Smoothing capacitor 20: SMR
22: Sub battery 24: Sub power supply wiring 26: Auxiliary machine 28: First circuit 30: Second circuit 31, 41, 45: Backflow prevention switch 32: Third circuit 36: Transformer 36a: Second coil 36b: Third coil 36c: 1st coil

Claims (1)

A main battery,
Main power supply wiring connected to the main battery;
A power control unit connected to the main power supply wiring and including a smoothing capacitor for smoothing the voltage of the main power supply wiring ;
A sub battery having a lower voltage than the main battery;
Sub power supply wiring connected to the sub battery;
A switch that switches between conduction and non-conduction of the main power supply wiring between the main battery and the power control unit by power supplied from the sub-battery,
A plurality of auxiliary machines operated by electric power supplied from the sub-battery;
A transformer including a first coil, a second coil, and a third coil;
A first circuit that connects the main coil and the first coil on the main battery side of the switch;
A second circuit that connects the main coil and the second coil closer to the power control unit than the switch;
A third circuit connecting the sub power supply wiring and the third coil;
With
The first circuit has a function of a DC-AC converter;
The second circuit has a function of an AC-DC converter;
The third circuit has an AC-DC converter function;
One of the plurality of auxiliary machines is a control device,
Prior to switching the main power supply wiring from the non-conductive state to the conductive state by the switch, the control device operates the first circuit so that the sub power source is connected from the main battery via the transformer and the third circuit. Supply processing for supplying power to the wiring is started, and thereafter, power is supplied from the sub-battery to the auxiliary machines not involved in the operation of the first circuit among the plurality of auxiliary machines, and the operation of the first circuit During the precharge, power is supplied from the main battery to the smoothing capacitor via the transformer and the second circuit, and after the precharge is completed, the switch is switched to disconnect the main power supply wiring from the non-conduction An automobile that executes a processing procedure for switching from continuity to conduction.

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