Power supply equipment

Abstract

To provide a power supply device that can be expected to prevent an auxiliary battery mounted on an electric vehicle from running out of battery.SOLUTION: A power supply device according to the present embodiment is a power supply device that can transfer power between a main battery mounted on an electric vehicle and an external device and includes: a first power path connected to the main battery and the external device; a second power path connected to the auxiliary battery and a control power supply circuit mounted on the electric vehicle; and a power supply circuit that receives power from the first power path and supplies power to the control power supply circuit. The power supply device includes a power supply selection circuit that selects power supplied from one of the power supply circuit and the auxiliary battery with a high output voltage and supplies the selected power to the control power supply circuit, and the output voltage of the power supply circuit may be higher than the output voltage of the auxiliary battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply device that supplies and receives electric power between a main battery mounted on an electric vehicle and an external device. [Background technology]

[0002] Electric vehicles have recently become popular. Electric vehicles use a large-capacity lithium-ion battery as the main battery, and the electric motor used for driving the vehicle is powered by the electric power stored in the main battery. In addition to the main battery, electric vehicles generally also have an auxiliary battery, such as a lead-acid battery, that serves as a power source for electrical components. The auxiliary battery is charged by the electric power stored in the main battery while the electric vehicle is running.

[0003] Patent Document 1 proposes an electric vehicle charging device that charges the main battery from an external AC power source via a charger, and charges the auxiliary battery from the main battery via a DC-DC converter. This electric vehicle charging device is configured to stop operation of the DC-DC converter while the charger performs constant current charging at the beginning of charging, thereby reducing the capacity and size of the charger. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-111711 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, wireless charging systems that charge the main battery of an electric vehicle without using a charging cable or the like have been put into practical use. Electric vehicles that support wireless charging are equipped with a device that controls charging and communicates with the outside world, and this device operates on power supplied from an auxiliary battery. In electric vehicles in which the auxiliary battery is not charged while the main battery is being charged, as in the electric vehicle charging device described in Patent Document 1, power from the auxiliary battery is consumed while the main battery is being charged, which could result in the auxiliary battery running out of power.

[0006] In addition, the main battery installed in an electric vehicle may be used to extract stored power to operate an external device, such as a welding machine. In such cases, power from the auxiliary battery is consumed for control and communication between the electric vehicle and the external device, which may result in the auxiliary battery running out of power.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a power supply device that can be expected to prevent the auxiliary battery mounted on an electric vehicle from running out of power. [Means for solving the problem]

[0008] A power supply device according to one embodiment is a power supply device that exchanges power between a main battery mounted on an electric vehicle and an external device, and includes a first power path connecting the main battery and the external device, a second power path connecting an auxiliary battery mounted on the electric vehicle and a control power supply circuit, and a power supply circuit that receives power from the first power path and supplies power to the control power supply circuit. [Effects of the Invention]

[0009] In one embodiment, it is expected that the auxiliary battery mounted on the electric vehicle can be prevented from running out of power. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram for explaining the configuration of a power supply device according to a first embodiment. [Figure 2] FIG. 10 is a block diagram illustrating the configuration of a power supply device according to a second embodiment. [Figure 3] FIG. 10 is a block diagram for explaining the configuration of a power supply device according to a third embodiment. [Figure 4] FIG. 10 is a block diagram for explaining the configuration of a power supply device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific examples of power supply devices according to embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0012] <First Embodiment> FIG. 1 is a block diagram for explaining the configuration of a power supply device according to a first embodiment. In this diagram, power supply paths are indicated by solid lines, and transmission paths for control signals and the like are indicated by dashed arrows. A vehicle 1 according to the first embodiment is an electric vehicle that travels by driving a motor 6 with power stored in a main battery 5 such as a lithium-ion battery. Note that the vehicle 1 may include a so-called hybrid electric vehicle that is equipped with both a motor 6 for travel and an engine that generates power by burning fuel.

[0013] Furthermore, vehicle 1 according to the first embodiment is a vehicle equipped with a function for charging main battery 5 contactlessly without using a charging cable, a so-called wireless charging function. Vehicle 1 is equipped with a power supply device 3 having a power receiving coil 2, an AC / DC converter 4, main battery 5, a motor 6, a DC / DC converter 7, an auxiliary battery 8, a control circuit 9, and the like. Of these, power receiving coil 2 and power supply device 3 are functional blocks for realizing the wireless charging function, and do not need to be installed in electric vehicles that do not have the wireless charging function.

[0014] In contrast, the AC / DC converter 4, main battery 5, motor 6, DC / DC converter 7, auxiliary battery 8, and control circuit 9 are functional blocks that are installed in an electric vehicle regardless of whether or not it has a wireless charging function. In the case of an electric vehicle that does not have a wireless charging function, for example, a power supply device installed outside the vehicle is connected to the AC / DC converter 4 of the electric vehicle via a charging cable, and AC power is supplied from the power supply device via the charging cable. The AC / DC converter 4 converts this AC power to DC power and supplies it to the main battery 5, thereby charging the main battery 5.

[0015] The power stored in the main battery 5 is supplied to the motor 6, and this power rotates the motor 6, thereby rotating the wheels of the vehicle 1 and causing the vehicle 1 to travel. The main battery 5 is also connected to a DC / DC converter 7 via a switch SW, which is controlled by a control circuit 9 to turn on and off, and when the switch SW is switched to the on state, the stored power is supplied to the DC / DC converter 7. The DC / DC converter 7 is a circuit that converts the voltage value of the direct current power supplied from the main battery 5. The output voltage value of the main battery 5 is, for example, several hundred volts, and the DC / DC converter 7 converts this several hundred volts of power to, for example, 12 V and outputs it. The 12 V direct current power output by the DC / DC converter 7 is supplied to the auxiliary battery 8, which charges the auxiliary battery 8.

[0016] The auxiliary battery 8 stores power supplied from the main battery 5 via the DC / DC converter 7 and supplies 12V DC power to electrical components other than the motor 6 mounted on the vehicle 1, such as a control circuit 9. The control circuit 9 controls various electrical components mounted on the vehicle 1 and operates on power supplied from the auxiliary battery 8. In this embodiment, the control circuit 9 controls switching between energization and de-energization of a switch SW provided between the main battery 5 and the DC / DC converter 7 depending on the on / off state of an ignition switch or an accessory switch of the vehicle 1. For example, the control circuit 9 turns the switch SW off when the vehicle 1 is not running and wireless charging is performed (the ignition switch is off). As a result, while the vehicle 1 is being wirelessly charged, power is not supplied from the main battery 5 to the auxiliary battery 8, and the auxiliary battery 8 is not charged.

[0017] The power supply device 3 according to the first embodiment can be added to an electric vehicle that charges the main battery 5 via a charging cable as described above, thereby adding a wireless charging function to the electric vehicle. By consolidating the wireless charging function in the power supply device 3 in this way, it is expected that the manufacturing process and components will be standardized between electric vehicles with and without the wireless charging function. It is also expected that it will be easier to add a wireless charging function to electric vehicles that do not have the wireless charging function.

[0018] Wireless charging is a technology for wirelessly transmitting power from a power transmission coil (not shown) provided in a power supply device installed outside the vehicle 1 to a power receiving coil 2 provided in a power supply device 3 of the vehicle 1, for example, by using an electromagnetic induction method or a magnetic resonance method. The power receiving coil 2 is placed, for example, on the bottom of the vehicle 1, and the power transmitting coil of the power supply device is placed in a predetermined space, for example, a parking lot or a road. When the vehicle 1 is parked in this predetermined space, the power receiving coil 2 of the vehicle 1 and the power transmitting coil of the external power supply device come close to each other, and wireless power transmission from the power transmitting coil to the power receiving coil 2 takes place.

[0019] The power supply device 3 according to this embodiment is configured to include a power receiving coil 2, a control circuit 31, a rectifying and smoothing circuit 32, a DC / AC converter 33, a DC / DC converter 34, a capacitor 35, a diode D1, and a diode D2. The control circuit 31 controls the operation of each component in the power supply device 3 to perform wireless charging. In the illustrated example, the control circuit 31 controls the operation of the DC / AC converter 33 to output power received by the power receiving coil 2 from a power supply device outside the vehicle 1 to the AC / DC converter 4 of the vehicle 1, thereby charging the main battery 5. The control circuit 31 may also wirelessly transmit and receive information about wireless charging to and from a power supply device installed outside the vehicle 1, for example.

[0020] The input terminal of the power supply of the control circuit 31 is connected to the output terminal of the DC / DC converter 34 via a diode D1, and is also connected to the auxiliary battery 8 via a diode D2. This allows the control circuit 31 to operate using power supplied from the DC / DC converter 34 via the diode D1, or power supplied from the auxiliary battery 8 via the diode D2.

[0021] The rectifying and smoothing circuit 32 is a combination of a rectifying circuit that rectifies AC current to DC current and a smoothing circuit that smooths pulsating current contained in the rectified DC current, and converts the AC power received by the power receiving coil 2 into DC power and outputs it. A DC / AC converter 33, a DC / DC converter 34, and a capacitor 35 are connected to the output terminal of the rectifying and smoothing circuit 32, respectively.

[0022] The DC / AC converter 33 is a circuit that converts DC power into AC power and outputs it. The DC / AC converter 33 switches the output on / off and controls the voltage value of the output power, etc., based on a control signal provided by the control circuit 31. The reason why the power supply device 3 according to this embodiment includes the DC / AC converter 33 is that the power supply device 3 outputs AC power suitable for input to the AC / DC converter 4, since the main battery 5 of the vehicle 1 is charged with DC power output by the AC / DC converter 4. Therefore, in the block diagram shown in FIG. 1 , the AC / DC converter 4 and the DC / AC converter 33 may be omitted, and the power output by the rectifying and smoothing circuit 32 may be directly supplied to the main battery 5.

[0023] The DC / DC converter 34 is a circuit that converts the voltage value of the power output by the rectifying and smoothing circuit 32 into a predetermined voltage value and outputs it. In this embodiment, the DC / DC converter 34 outputs power at a voltage value (e.g., 15 V) that is higher than the output voltage value (e.g., 12 V) of the auxiliary battery 8. The output terminal of the DC / DC converter 34 is connected to the (power supply) input terminal of the control circuit 31 via a diode D1, and the control circuit 31 can operate using the power supplied from the DC / DC converter 34.

[0024] Capacitor 35 is a circuit element that temporarily stores the power (charge) output by rectifying and smoothing circuit 32. When wireless charging is started, AC power received by power receiving coil 2 is converted to DC power by rectifying and smoothing circuit 32 and output, and the power output by rectifying and smoothing circuit 32 is stored in capacitor 35. By storing power in capacitor 35, even if, for example, wireless charging is temporarily interrupted, DC / AC converter 33 and DC / DC converter 34 can continue to operate using the power stored in capacitor 35.

[0025] Diodes D1 and D2 are circuit elements that allow current to flow from anode to cathode but prevent current from flowing from cathode to anode. The anode of diode D1 is connected to the output terminal of DC / DC converter 34, and the cathode is connected to the power input terminal of control circuit 31. Power is supplied from DC / DC converter 34 to control circuit 31 via diode D1, but no current flows from control circuit 31 to DC / DC converter 34. The anode of diode D2 is connected to auxiliary battery 8, and the cathode is connected to the power input terminal of control circuit 31. Power is supplied from auxiliary battery 8 to control circuit 31 via diode D2, but no current flows from control circuit 31 to auxiliary battery 8. Diodes D1 and D2 may be common-cathode center-tap diodes incorporating two diodes.

[0026] The diodes D1 and D2 included in the power supply device 3 according to this embodiment constitute a selection circuit for selecting the power to be supplied to the control circuit 31. This selection circuit selects between the power from the DC / DC converter 34 and the power from the auxiliary battery 8 and supplies the selected power to the control circuit 31 depending on whether the DC / DC converter 34 is operating or not, i.e., whether wireless charging is being performed or not.

[0027] That is, when the DC / DC converter 34 is not operating, power output from the auxiliary battery 8, for example, at a voltage of 12 V, is supplied to the control circuit 31 via the diode D2. When the DC / DC converter 34 is operating, power output from the DC / DC converter 34, for example, at a voltage of 15 V, is supplied to the control circuit 31 via the diode D1. As a result, the anode voltage of the diode D2 is 12 V, while the cathode voltage is 15 V, so that the diode D2 enters a cutoff state in which no current flows, and the power supply from the auxiliary battery 8 to the control circuit 31 is stopped. Note that in this embodiment, the output voltage of the DC / DC converter 34 is set to be higher than the output voltage of the auxiliary battery 8.

[0028] When the vehicle 1 according to this embodiment is traveling, power is supplied from the main battery 5 to the motor 6. At this time, the control circuit 9 sets the switch SW to a conducting state, and power from the main battery 5 is supplied to the auxiliary battery 8 via the DC / DC converter 7, thereby charging the auxiliary battery 8. When the vehicle 1 is parked in a parking lot or the like that is provided with a power supply device for charging the main battery 5, and for example, the ignition switch is switched to the off state, the control circuit 9 switches the switch SW to a cut-off state, thereby cutting off the power supply from the main battery 5 to the auxiliary battery 8.

[0029] At this time, the control circuit 31 of the power supply device 3 communicates wirelessly with, for example, a power feeding device installed outside the vehicle 1, and performs a predetermined procedure required for wireless charging. At this time, the control circuit 31 operates using power supplied from the auxiliary battery 8 via diode D2. After the predetermined procedure required for wireless charging is completed, wireless power transmission begins from the power transmitting coil of the external power feeding device to the power receiving coil 2 of the vehicle 1, and the control circuit 31 starts operating the DC / AC converter 33. The power received by the power receiving coil 2 is supplied to the main battery 5 via the rectifying and smoothing circuit 32, the DC / AC converter 33, and the AC / DC converter 4, and the main battery 5 is charged.

[0030] When the power receiving coil 2 receives power, the power output by the rectifying and smoothing circuit 32 is supplied to the DC / DC converter 34, causing the DC / DC converter 34 to start operating. The DC / DC converter 34 outputs power at a voltage value (e.g., 15 V) higher than the output voltage value (e.g., 12 V) of the auxiliary battery 8, and this power is supplied to the control circuit 31 via the diode D1. As power is supplied from the DC / DC converter 34 to the control circuit 31, the cathode of the diode D2 has a voltage value equal to or close to the output voltage value (e.g., 15 V) of the DC / DC converter 34. The voltage value of the anode of the diode D2 is the output voltage value (e.g., 12 V) of the auxiliary battery 8, and because the voltage value of the cathode of the diode D2 is higher than the voltage value of the anode, the diode D2 is turned off, and the power supply from the auxiliary battery 8 to the control circuit 31 is stopped.

[0031] The power supply device 3 according to the first embodiment configured as described above is a device that exchanges power between a main battery 5 mounted on a vehicle 1 such as an electric vehicle and an external power supply device. The power supply device 3 includes a first power path (i.e., a power path including a power path (such as a wiring or cable) between the power receiving coil 2 and the rectifying and smoothing circuit 32, a power path between the rectifying and smoothing circuit 32 and the DC / AC converter 33, and a power path between the DC / AC converter 33 and the AC / DC converter 4) that connects the main battery 5 and the external power supply device. The power supply device 3 also includes a second power path (i.e., a power path including a power path between the auxiliary battery 8 and the anode of a diode D2, and a power path between the cathode of the diode D2 and the control circuit 31) that connects the auxiliary battery 8 and the control circuit 31 mounted on the vehicle 1. The power supply device 3 also includes a DC / DC converter 34 that receives power from the first power path and supplies the power to the control circuit 31.

[0032] With these configurations, when wireless charging is not being performed, the power supply device 3 according to the first embodiment can supply power from the auxiliary battery 8 of the vehicle 1 to the control circuit 31 to operate the control circuit 31. When wireless charging is being performed, the power supply device 3 can supply power from the DC / DC converter 34 to the control circuit 31 to operate the control circuit 31, which is expected to prevent the auxiliary battery 8 from running out.

[0033] The power supply device 3 according to the first embodiment also includes a power supply selection circuit that selects power supplied from either the DC / DC converter 34 or the auxiliary battery 8, whichever has the higher output voltage, and supplies the selected power to the control circuit 31. The power supply selection circuit has two diodes D1 and D2, with the anode of the diode D1 connected to the output terminal of the DC / DC converter 34, the anode of the diode D2 connected to the second power path, and the cathodes of the diodes D1 and D2 connected to each other and to the control circuit 31. This allows the output voltage value of the DC / DC converter 34 to be set higher than the output voltage value of the auxiliary battery 8, so that when the DC / DC converter 34 is operating, power can be supplied from the DC / DC converter 34 to the control circuit 31 and power supply from the auxiliary battery 8 to the control circuit 31 can be stopped.

[0034] In the first embodiment, power supply device 3 is configured to supply power of a predetermined voltage value output by DC / DC converter 34 based on the power output by rectifying and smoothing circuit 32 to control circuit 31 via diode D1, but the present invention is not limited to this. Power supply device 3 may be configured to include an AC / DC converter instead of DC / DC converter 34, convert AC power output by DC / AC converter 33 into DC power by this AC / DC converter, and supply this power to control circuit 31.

[0035] <Embodiment 2> 2 is a block diagram for explaining the configuration of a power supply device 3 according to a second embodiment. The power supply device 3 according to the second embodiment has a configuration in which a voltage detection unit 37 is added to the configuration of the power supply device 3 according to the first embodiment shown in FIG. 1. The voltage detection unit 37 is connected to an appropriate location on the power supply path between, for example, the auxiliary battery 8 and the diode D2. The voltage detection unit 37 detects the voltage value on this power supply path (the output voltage value of the auxiliary battery 8 and the voltage value at the anode of the diode D2) and outputs the detected voltage value to the control circuit 31.

[0036] The control circuit 31 of the power supply device 3 according to the second embodiment controls the operation of the DC / DC converter 34 in accordance with the voltage value detected by the voltage detection unit 37. The control circuit 31 determines whether the voltage value detected by the voltage detection unit 37 exceeds a predetermined voltage value, and if the detected voltage value exceeds the predetermined voltage value, i.e., if it is estimated that sufficient power has been stored in the auxiliary battery 8, the control circuit 31 stops the operation of the DC / DC converter 34. On the other hand, if the detected voltage value does not exceed the predetermined voltage value, i.e., if it is estimated that the power stored in the auxiliary battery 8 is decreasing, the control circuit 31 operates the DC / DC converter 34.

[0037] The power supply device 3 according to the second embodiment configured as described above detects the output voltage value of the auxiliary battery 8 using the voltage detection unit 37, and if the detected voltage value exceeds a predetermined voltage value, stops the power supply from the DC / DC converter 34. As a result, if it is estimated that sufficient power has accumulated in the auxiliary battery 8, the power supply device 3 can allocate the power for operating the DC / DC converter 34 to charging the main battery 5, and it is expected that efficient charging of the main battery 5 can be achieved.

[0038] Note that, although the power supply device 3 according to the second embodiment is configured to stop the operation of the DC / DC converter 34 in accordance with the voltage value detected by the voltage detection unit 37, the present invention is not limited to this. For example, the power supply device 3 may perform control to change the output voltage value of the DC / DC converter 34 in accordance with the voltage value detected by the voltage detection unit 37.

[0039] Furthermore, other configurations of the power supply device 3 according to the second embodiment are similar to those of the power supply device 3 according to the first embodiment, so the same reference numerals are used for the same parts and detailed description thereof will be omitted.

[0040] <Third Embodiment> 3 is a block diagram for explaining the configuration of a power supply device 3 according to a third embodiment. The power supply device 3 according to the third embodiment corresponds to the configuration of the power supply device 3 according to the first embodiment shown in FIG. 1, in which the diodes D1 and D2 are removed and the DC / DC converter 34 is replaced with a charging circuit 36. More specifically, in the power supply device 3 according to the third embodiment, the power input terminal of the control circuit 31 and the output terminal of the auxiliary battery 8 are directly connected without an intervening diode or the like. The control circuit 31 operates on power supplied from the auxiliary battery 8.

[0041] The charging circuit 36 ​​operates based on the power output by the rectifying and smoothing circuit 32, and outputs power of a predetermined voltage value at which the control circuit 31 operates. The charging circuit 36 ​​is also a circuit that can perform constant current output operation at a predetermined current value required to charge the auxiliary battery 8, even when the auxiliary battery 8 is connected to its output and the output voltage value of the auxiliary battery 8 is lower than the predetermined voltage value.

[0042] When wireless charging is initiated and the rectifying and smoothing circuit 32 outputs DC power, the charging circuit 36 ​​starts outputting a constant current. The current of a predetermined value output by the charging circuit 36 ​​is supplied to the control circuit 31 and the auxiliary battery 8, which operates the control circuit 31 and charges the auxiliary battery 8.

[0043] In the power supply device 3 according to the third embodiment configured as described above, when wireless charging is being performed, the charging circuit 36 ​​supplies a constant current to the control circuit 31 and the auxiliary battery 8, thereby operating the control circuit 31 and charging the auxiliary battery 8. Therefore, the power supply device 3 according to the third embodiment is expected to prevent the auxiliary battery 8 from running out of power.

[0044] The other configurations of the power supply device 3 according to the third embodiment are similar to those of the power supply device 3 according to the first and second embodiments, so the same reference numerals are used for the same parts and detailed description thereof will be omitted.

[0045] <Fourth Embodiment> 4 is a block diagram for explaining the configuration of a power supply device 3 according to embodiment 4. The power supply devices 3 according to the above-described embodiments 1 to 3 are configured to supply power from a power feeding device provided outside the vehicle 1 to the main battery 5 inside the vehicle 1. In contrast, the power supply device 3 according to embodiment 4 is configured to supply power stored in the main battery 5 inside the vehicle 1 to various devices outside the vehicle 1.

[0046] In the fourth embodiment, a welding machine 51 having the functions of the power supply device 3 will be described as an example of a device external to the vehicle 1, but the external device is not limited to the welding machine 51 and may be any device. The vehicle 1 according to the fourth embodiment has a function of supplying power stored in the main battery 5 to an external device, for example, by connecting a power supply cable to a plug disposed in an appropriate location on the vehicle body. Note that the plug to which the power supply cable for external power supply is connected may be the same as or different from the plug to which a charging cable is connected when the main battery 5 is charged via a wire.

[0047] Welding machine 51 according to the fourth embodiment is provided outside vehicle 1 and operates using power supplied from vehicle 1. Welding machine 51 according to the fourth embodiment includes control circuit 31, DC / DC converter 34, and diodes D1 and D2 similar to those of power supply device 3 according to the first embodiment, as well as rectifying and smoothing circuit 52, inverter 53, rectifying circuit 54, and the like.

[0048] When the welding machine 51 is connected to the vehicle 1, the power output from the main battery 5 of the vehicle 1 is supplied to each section (not shown) within the welding machine 51 via the rectifying and smoothing circuit 52, inverter 53, and rectifying circuit 54 of the welding machine 51. The rectifying and smoothing circuit 52 is a combination of a rectifying circuit that rectifies current and a smoothing circuit that smooths current, and outputs the power from the main battery 5 of the vehicle 1 as DC power. The inverter 53 and the DC / DC converter 34 are connected to the output terminal of the rectifying and smoothing circuit 52, respectively.

[0049] Inverter 53 is a circuit that converts DC to AC. Inverter 53 converts the DC power output by rectifying and smoothing circuit 52 into AC power of a predetermined voltage value and a predetermined frequency under the control of control circuit 31 and outputs the AC power. Rectifier circuit 54 is connected to the output terminal of inverter 53, and rectifier circuit 54 converts the AC power output by inverter 53 into DC power and supplies it to each component in welding machine 51. Each component of welding machine 51 operates using the DC power output by rectifier circuit 54.

[0050] The DC / DC converter 34 is a circuit that converts the voltage value of the power output by the rectifying and smoothing circuit 52 to a predetermined voltage value, for example, a voltage value (15 V) that is higher than the output voltage value (12 V) of the auxiliary battery 8, and outputs the converted voltage. Diodes D1 and D2 form a selection circuit for selecting the power to be supplied to the control circuit 31, and selects between the power from the DC / DC converter 34 and the power from the auxiliary battery 8 and supplies the selected power to the control circuit 31 depending on whether the DC / DC converter 34 is operating.

[0051] For example, a user of vehicle 1 and welding machine 51 connects welding machine 51 to vehicle 1, which is parked, via a power supply cable. When the power supply cable is connected to vehicle 1, rectifying and smoothing circuit 52 of welding machine 51 is electrically connected to main battery 5 of vehicle 1, and the anode of diode D2 is electrically connected to auxiliary battery 8 of vehicle 1. As a result, power stored in auxiliary battery 8 is supplied to control circuit 31 through diode D2, and control circuit 31 operates using this power supply. Control circuit 31 exchanges various information regarding power supply with vehicle 1, for example, and then operates inverter 53 to start supplying power to each component provided in welding machine 51. At this time, vehicle 1 also exchanges various information regarding power supply with power supply device 3, for example, and then starts supplying power to welding machine 51.

[0052] Power from the main battery 5 of the vehicle 1 is supplied to the welding machine 51, and this power is then supplied to each section of the welding machine 51 via the rectifying and smoothing circuit 52, inverter 53, and rectifying circuit 54 of the power supply device 3. The direct current power output from the rectifying and smoothing circuit 52 is supplied to the DC / DC converter 34, which converts the supplied power to a predetermined voltage value (a voltage value higher than the output voltage value of the auxiliary battery 8) and outputs it. The power output from the DC / DC converter 34 is supplied to the control circuit 31 via the diode D1. As a result, the voltage value of the cathode of the diode D2 becomes higher than the voltage value of the anode, so that the diode D2 is turned off and the power supply from the auxiliary battery 8 to the control circuit 31 is cut off.

[0053] The power supply device according to the fourth embodiment having the above configuration is a device that exchanges power between main battery 5 mounted on vehicle 1 such as an electric vehicle and an external device such as welding machine 51. Welding machine 51, which functions as a power supply device, includes a first power path (i.e., rectifying and smoothing circuit 52, inverter 53, rectifying circuit 54, and a power path (wiring, cable, etc.) between them) that connects main battery 5 and the external device (each part of welding machine 51). Welding machine 51 also includes a second power path (i.e., a power path that includes a power path between auxiliary battery 8 and the anode of diode D2, and a power path between the cathode of diode D2 and control circuit 31) that connects auxiliary battery 8 mounted on vehicle 1 and control circuit 31. Welding machine 51 also includes DC / DC converter 34 that receives power from the first power path and supplies the power to control circuit 31.

[0054] With these configurations, welding machine 51 according to the fourth embodiment can supply power from auxiliary battery 8 of vehicle 1 to control circuit 31 to operate control circuit 31 until power supply from main battery 5 of vehicle 1 begins. Furthermore, after power supply from main battery 5 of vehicle 1 begins, welding machine 51 can supply power from DC / DC converter 34 to control circuit 31 to operate control circuit 31, which is expected to prevent auxiliary battery 8 from running out of power.

[0055] Welding machine 51 according to the fourth embodiment may be configured to include charging circuit 36 ​​to charge auxiliary battery 8, similar to power supply device 3 according to the third embodiment. Welding machine 51 according to the fourth embodiment may also be configured to include voltage detection unit 37 to detect the output voltage value of auxiliary battery 8, and to control the operation of DC / DC converter 34 in accordance with the detection result, similar to power supply device 3 according to the second embodiment.

[0056] The other configurations of the welding machine (power supply device) 51 according to the fourth embodiment are similar to those of the power supply device 3 according to the first to third embodiments, so the same reference numerals are used for the same parts and detailed description thereof will be omitted.

[0057] The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0058] 1 vehicle 2 receiving coil 3 Power supply device 4 AC / DC converters 5 Main Battery 6 motors 7 DC / DC converter 8 Auxiliary Battery 9 Control Circuit 31 Control circuit (control power circuit) 32 Rectifier smoothing circuit 33 DC / AC converter 34 DC / DC converter (power supply circuit) 35 Capacitor 36 Charging circuit (power supply circuit) 37 Voltage detection section 51 Welding machine 52 Rectifier smoothing circuit 53 Inverter 54 Rectifier circuit D1, D2 Diodes (power supply selection circuit) SW switch

Claims

[Claim 1] A power supply device that exchanges power between a main battery mounted on an electric vehicle and an external device, a first power path leading to the main battery and the external device; a second power path connected to an auxiliary battery and a control power supply circuit mounted on the electric vehicle; a power supply circuit that receives power from the first power path and supplies power to the control power supply circuit; Equipped with the power supply circuit is a circuit that outputs a constant current and charges the auxiliary battery via the second power path; Power supply device.

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