Vehicle power supply

Abstract

To provide a technique for protecting an inverter inside a PCU while consuming energy so as not to apply a load to an external device connected to the PCU when system abnormality of the PCU occurs in a vehicle.SOLUTION: When a voltage value of a capacitor included in a PCU is equal to or higher than a predetermined value, a vehicle power supply device turns on both a positive electrode switching element and a negative electrode switching element corresponding to one resistor so as to enable one resistor among a plurality of resistors connected to the PCU whose initial state is invalid. In addition, the vehicle power supply device turns on both the positive electrode switching element and the negative electrode switching element corresponding to another resistor so as to disable one resistor and enable the other resistor among the plurality of resistors based on predetermined conditions.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a power supply device for a vehicle.

Background Art

[0002] Patent Document 1 discloses a hydroelectric power generation system connection system using a general-purpose power conditioner (PCS). The hydroelectric power generation system connection system includes a generator that converts the rotational energy of a waterwheel into electrical energy, a rectifier that converts the generated power of the generator into DC power, and a control device that adjusts the load of the generator to control the rotational speed of the waterwheel. In this technology, when an overvoltage occurs due to the high-speed rotation of the waterwheel or the like, the switch function of the rectifier is controlled to be turned off. As a result, the generator and the PCS are disconnected to prevent the generated power from being consumed. Further, the overvoltage power generated due to the high-speed rotation of the waterwheel or the like is absorbed by a consumption resistor device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the power supply device of a vehicle, it is necessary to assume that an abnormality occurs in the system between the PCS (Power Control Unit) connected to the PCU and the generator. When the rotational speed of an external device (motor) connected to the generator becomes equal to or higher than the allowable rotational speed, by flowing a current through a resistor connected to the PCU to consume energy, it is possible to suppress the rotational speed of the motor from becoming equal to or higher than the allowable rotational speed. However, when a current of a predetermined value or more is continuously applied to the resistor, the temperature of the inverter connected to the resistor becomes equal to or higher than the allowable temperature, which may cause a failure of the inverter.

[0005] One objective of this disclosure is to provide a technology that protects the inverter inside the PCU while consuming energy to avoid putting a load on external devices connected to the PCU in the event of a system malfunction in the PCU in a vehicle. [Means for solving the problem]

[0006] The first aspect of this disclosure relates to a vehicle power supply unit. The vehicle power supply unit comprises a PCU and a plurality of resistors connected to the PCU. The PCU includes a capacitor, a voltage sensor for measuring the voltage of the capacitor, a three-phase inverter connected in parallel to the capacitor, and a control device connected to the voltage sensor and the three-phase inverter. The positive terminal of each of the plurality of resistors is connected to a positive power line via one of a plurality of positive switching elements provided on the positive side of each phase of the three-phase inverter. The negative terminal of each of the plurality of resistors is connected to a negative power line via one of a plurality of negative switching elements provided on the negative side of each phase of the three-phase inverter. The negative terminal is connected to a negative power line via a negative switching element of one of two phases different from the phase on which the positive switching element connected to the positive terminal is provided. The control device turns ON both the positive switching element and the negative switching element corresponding to one of the plurality of resistors, which are initially inactive, to enable that resistor. Furthermore, if predetermined conditions are met, the control device turns on both the positive and negative switching elements corresponding to one of the multiple resistors, thereby disabling one resistor and enabling another resistor from among the multiple resistors.

[0007] A second aspect of this disclosure relates to a vehicle power supply method. The vehicle control method includes, when the voltage value of a capacitor included in the PCU is greater than or equal to a predetermined value, turning on both the positive and negative switching elements corresponding to one resistor so as to enable one of a plurality of resistors connected to the PCU, which is initially disabled, and, based on predetermined conditions, turning on both the positive and negative switching elements corresponding to another resistor so as to disable one resistor and enable another resistor among the plurality of resistors. [Effects of the Invention]

[0008] According to this disclosure, when a voltage anomaly, which is an example of a system abnormality in the PCU, is detected, one of the multiple resistors is activated in a rotational manner. This allows energy to be consumed without putting a load on external devices connected to the PCU, while suppressing the inverter from overheating. Therefore, it is possible to avoid inverter failure. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing an example configuration of a vehicle power supply device according to an embodiment. [Figure 2] This is an explanatory diagram showing a specific example of a vehicle power supply device according to an embodiment. [Figure 3] This is an explanatory diagram showing a comparative example of a vehicle power supply device according to an embodiment. [Figure 4] This is an explanatory diagram showing a specific example of a vehicle power supply device according to an embodiment. [Figure 5] This flowchart shows a first processing example of a vehicle power supply device according to an embodiment. [Figure 6] This flowchart shows a second processing example of the vehicle power supply device according to the embodiment. [Modes for carrying out the invention]

[0010] A vehicle power supply device and a vehicle power supply method according to embodiments of this disclosure will be described with reference to the attached drawings. In addition, elements common to each figure are denoted by the same reference numerals, and redundant explanations are omitted.

[0011] 1. Example Configuration Figure 1 is a block diagram showing an example configuration of a vehicle power supply unit 1 according to an embodiment. The vehicle power supply unit 1 is mounted on a vehicle and used to supply power used in the vehicle. However, the vehicle power supply unit 1 may also be used as a power generation system to supply power to the outside of the vehicle. The vehicle on which the vehicle power supply unit 1 is mounted may be a manually driven vehicle or an autonomous vehicle.

[0012] As shown in Figure 1, the vehicle power supply unit 1 consists of a PCS2, a PCU4, an external device 3, and a plurality of resistors 50. One end of the PCS2 is connected to the positive power line 7, and the other end is connected to the negative power line 8. The PCU4 is connected to the PCS2, the external device 3, and the plurality of resistors 50. The PCS2 is a device that has the function of converting power obtained from commercial power, solar power generation, etc. into power that can be used by vehicles, etc. The PCU4 is a power conversion device that converts power with the PCS2. The external device 3 is a generator, motor, etc. The plurality of resistors 50 includes a first resistor 50A, a second resistor 50B, and a third resistor 50C. The first resistor 50A, the second resistor 50B, and the third resistor 50C are resistors that absorb (consume) energy when the power in the system between the PCS2 and the PCU4 is overvoltage power. The negative power line 8 mentioned above is energized to ground (not shown).

[0013] The PCU4 is comprised of a capacitor 6, a first inverter 10, a second inverter 20, a voltage sensor 5, and a control device 100.

[0014] Capacitor 6 is connected to the positive power line 7 on one end and to the negative power line 8 on the other end. Capacitor 6 is a component that smooths the DC voltage input from PCS2 and charges and discharges energy.

[0015] The first inverter 10 is connected in parallel to the capacitor 6. Specifically, one end of the first inverter 10 is connected to the positive power line 7, and the other end is connected to the negative power line 8. The second inverter 20 is also connected in parallel to the capacitor 6. Similar to the first inverter 10, one end of the second inverter 20 is connected to the positive power line 7, and the other end is connected to the negative power line 8. The first inverter 10 and the second inverter 20 are devices that convert the DC voltage input to the PCU 4 into an AC voltage of any desired voltage and frequency and output it. The first inverter 10 and the second inverter 20 are examples of three-phase inverters (three-level inverters) that generate and output three-phase power. An example of a three-level inverter is an IPM (Intelligent Power Module).

[0016] The first inverter 10 includes a plurality of positive electrode switching elements provided on the positive electrode side of each phase and a plurality of negative electrode switching elements provided on the negative electrode side of each phase. The plurality of positive electrode switching elements include a first positive electrode switching element (first switching element 11) provided on the first phase (phase 1), a second positive electrode switching element (third switching element 13) provided on the second phase (phase 2), and a third positive electrode switching element (fifth switching element 15) provided on the third phase (phase 3). The plurality of negative electrode switching elements include a first negative electrode switching element (second switching element 12) provided on phase 1, a second negative electrode switching element (fourth switching element 14) provided on phase 2, and a third negative electrode switching element (sixth switching element 16) provided on phase 3.

[0017] One terminal of the first switching element 11 is connected to the positive power line 7, and the other terminal is connected to the first power line 31. One terminal of the second switching element 12 is connected to the first power line 31, and the other terminal is connected to the negative power line 8. One terminal of the third switching element 13 is connected to the positive power line 7, and the other terminal is connected to the second power line 32. One terminal of the fourth switching element 14 is connected to the second power line 32, and the other terminal is connected to the negative power line 8. One terminal of the fifth switching element 15 is connected to the positive power line 7, and the other terminal is connected to the third power line 33. One terminal of the sixth switching element 16 is connected to the third power line 33, and the other terminal is connected to the negative power line 8. The above-described external device 3 is connected to the first power line 31, the second power line 32, and the third power line 33. Thereby, the external device 3 is driven in three phases.

[0018] The second inverter 20 includes a plurality of positive switching elements provided on the positive electrode side of each phase and a plurality of negative switching elements provided on the negative electrode side of each phase. The plurality of positive switching elements include the first switching element 21 provided in the first phase, the third switching element 23 provided in the second phase, and the fifth switching element 25 provided in the third phase. The plurality of negative switching elements include the second switching element 22 provided in the first phase, the fourth switching element 24 provided in the second phase, and the sixth switching element 26 provided in the third phase.

[0019] One terminal of the first switching element 21 is connected to the positive power line 7, and the other terminal is connected to the first power line 41. One terminal of the second switching element 22 is connected to the first power line 41, and the other terminal is connected to the negative power line 8. One terminal of the third switching element 23 is connected to the positive power line 7, and the other terminal is connected to the second power line 42. One terminal of the fourth switching element 24 is connected to the second power line 42, and the other terminal is connected to the negative power line 8. One terminal of the fifth switching element 25 is connected to the positive power line 7, and the other terminal is connected to the third power line 43. One terminal of the sixth switching element 26 is connected to the third power line 43, and the other terminal is connected to the negative power line 8.

[0020] Based on the configuration of the second inverter 20, each of the above-described first resistor 50A, second resistor 50B, and third resistor 50C is connected as follows. Note that each of the first resistor 50A, second resistor 50B, and third resistor 50C is a resistor composed of a positive terminal (+) and a negative terminal (-).

[0021] The positive terminal (+) of the first resistor 50A is connected to the first power line 41, and the negative terminal (-) of the first resistor 50A is connected to the second power line 42. The positive terminal (+) of the second resistor 50B is connected to the second power line 42, and the negative terminal (-) of the second resistor 50B is connected to the third power line 43. The positive terminal (+) of the third resistor 50C is connected to the third power line 43, and the negative terminal (-) of the third resistor 50C is connected to the first power line 41.

[0022] That is, the positive terminal (+) of each of the plurality of resistors 50 is connected to the positive power line 7 through any one of the plurality of positive switching elements provided on the positive side of each phase of the second inverter 20. Also, the negative terminal (-) of each of the plurality of resistors 50 is connected to the negative power line 8 through any one of the plurality of negative switching elements provided on the negative side of each phase of the second inverter 20. Note that the negative terminal is connected to the negative power line 8 through the negative switching element of any one of the two phases different from the phase where the positive switching element connected to the positive terminal is provided.

[0023] The voltage sensor 5 is connected to the positive power line 7. The voltage sensor 5 is a sensor that measures the voltage value of the system between the PCS 2 and the external device 3.

[0024] The control device 100 is a computer that controls the vehicle power supply unit 1. The control device 100 may be mounted inside the PCU 4 or provided outside the PCU 4. The control device 100 is, for example, an ECU (Electronic Control Unit) and comprises a processor (not shown) and a memory (not shown) that stores a control program (the control program according to this embodiment) executed by the processor. The control device 100 realizes the functions described below when the control program is executed by the processor.

[0025] The control device 100 is connected to at least the voltage sensor 5 and the second inverter 20. Specifically, the control device 100 is connected to the first switching element 21, the second switching element 22, the third switching element 23, the fourth switching element 24, the fifth switching element 25, and the sixth switching element 26 in the second inverter 20.

[0026] The control device 100 determines whether the voltage value is above a predetermined value (i.e., a voltage anomaly) based on the voltage value information obtained from the voltage sensor 5. Furthermore, if the control device 100 determines that the voltage value is a voltage anomaly, it controls the ON / OFF switching of each switching element. In other words, if the control device 100 does not detect a voltage anomaly, it keeps all switching elements OFF. As a result, when the system between the PCS2 and the external device 3 is normal, the connection between the second inverter 20 and the resistor 50 is interrupted, preventing the power charged in the capacitor 6 from being consumed by the resistor 50.

[0027] 2. Specific Examples 2-1. Outline of Resistor Switching Examples Here, we consider the ON / OFF switching control of each switching element when a voltage anomaly occurs in the system between PCS2 and external device 3. In order to prevent a short circuit between the positive power line 7 and the negative power line 8, the first switching element 21 and the second switching element 22 of the first phase cannot be turned ON simultaneously. Also, the third switching element 23 and the fourth switching element 24 of the second phase cannot be turned ON simultaneously. Furthermore, the fifth switching element 25 and the sixth switching element 26 of the third phase cannot be turned ON simultaneously. Therefore, when a voltage anomaly occurs in the system between PCS2 and external device 3, it is not possible to simultaneously activate all of the first resistor 50A, the second resistor 50B, and the third resistor 50C as the resistors 50 to be activated. Also, it is not possible to simultaneously activate any two of the second resistor 50B and the third resistor 50C. The target resistor 50 is only one of the first resistor 50A, the second resistor 50B, and the third resistor 50C. The following describes in detail the ON / OFF switching examples for each switching element corresponding to the target resistor 50.

[0028] Figure 2 is an explanatory diagram showing a specific example of the vehicle power supply device 1 according to the embodiment. Specifically, Figure 2 is a diagram showing an example of switching ON / OFF each switching element of the second inverter 20 corresponding to the target resistor 50. For example, as shown in case (A) of Figure 2, when the target resistor 50 is the first resistor 50A, the control device 100 turns ON only the first switching element 21 and the fourth switching element 24. Also, as shown in case (B) of Figure 2, when the target resistor 50 is the second resistor 50B, the control device 100 turns ON only the third switching element 23 and the sixth switching element 26. Furthermore, as shown in case (C) of Figure 2, when the target resistor 50 is the third resistor 50C, the control device 100 turns ON only the second switching element 22 and the fifth switching element 25. This makes it possible to activate the target resistor 50 without short-circuiting the positive power line 7 and the negative power line 8.

[0029] Based on this, we will consider the temperature changes of the switching elements in the second inverter 20 when the target resistor 50 is enabled.

[0030] Figure 3 is an explanatory diagram showing a comparative example of the vehicle power supply device 1 according to the embodiment. Specifically, Figure 3 is a diagram showing an example of the temperature change of the switching element corresponding to the positive terminal (+) of the target resistor 50 when one of the resistors 50 from the first resistor 50A, the second resistor 50B, and the third resistor 50C is used.

[0031] Case (A) in Figure 3 shows the ON / OFF switching state of the switching element corresponding to the positive terminal (+) of resistor 50. Specifically, the first switch waveform 101 is a waveform that shows the ON / OFF switching state of the first switching element 21 corresponding to the positive terminal (+) of the first resistor 50A. The ON / OFF switching state of the fourth switching element 24 corresponding to the negative terminal (-) of the first resistor 50A is also represented by the first switch waveform 101. Furthermore, the third switch waveform 103 is a waveform that shows the ON / OFF switching state of the third switching element 23 corresponding to the positive terminal (+) of the second resistor 50B. The ON / OFF switching state of the sixth switching element 26 corresponding to the negative terminal (-) of the second resistor 50B is also represented by the third switch waveform 103. In addition, the fifth switch waveform 105 is a waveform that shows the ON / OFF switching state of the fifth switching element 25 corresponding to the positive terminal (+) of the third resistor 50C. The ON / OFF switching state of the second switching element 22, which corresponds to the negative terminal (-) of the third resistor 50C, is also represented by the fifth switch waveform 105.

[0032] For example, if the target resistor 50 is the first resistor 50A, the first switch waveform 101 corresponding to the first resistor 50A will be an ON waveform, as shown in case (A) of Figure 3. On the other hand, the third switch waveform 103 corresponding to the second resistor 50B, which is not used as the target resistor 50, will be an OFF waveform. Also, the fifth switch waveform 105 corresponding to the third resistor 50C, which is not used as the target resistor 50, will be an OFF waveform.

[0033] Next, if the target resistor 50 is the first resistor 50A, we consider the temperature changes of the first switching element 21 and the fourth switching element 24 corresponding to the first resistor 50A.

[0034] Case (B) in Figure 3 shows the temperature state of the switching element corresponding to the positive terminal (+) of resistor 50. Specifically, the first temperature waveform 111 is the waveform showing the temperature state of the first switching element 21 corresponding to the positive terminal (+) of the first resistor 50A. The third temperature waveform 113 is the waveform showing the temperature state of the third switching element 23 corresponding to the positive terminal (+) of the second resistor 50B. Furthermore, the fifth temperature waveform 115 is the waveform showing the temperature state of the fifth switching element 25 corresponding to the positive terminal (+) of the third resistor 50C.

[0035] As shown in case (B) of Figure 3, the first temperature waveform 111 is a waveform that rises to a temperature close to 100°C, which is above the rated temperature. In other words, it can be said that the temperature of the first switching element 21 corresponding to the positive terminal (+) of the first resistor 50A used as the target resistor 50 rises to a temperature close to 100°C. On the other hand, the third temperature waveform 113 and the fifth temperature waveform 115 are both waveforms that maintain a temperature of room temperature, below the rated temperature. This is because they are not used as the target resistor 50, and both the third switching element 23 and the fifth switching element 25 are in a non-operating state.

[0036] As shown in case (B) of Figure 3, if the temperature of the first temperature waveform 111 exceeds the rated temperature of the first switching element 21, the first switching element 21 may fail. The same applies to the fourth switching element 24 corresponding to the negative terminal (-) of the first resistor 50A. Therefore, when attempting to absorb abnormal power during a voltage anomaly using the resistor 50, temperature control is required to ensure that the temperature of the switching element corresponding to the resistor 50 does not exceed the rated temperature.

[0037] According to the vehicle power supply device 1 of the embodiment, the target resistor 50 is switched so that the temperature of the switching element corresponding to the target resistor 50 falls below a predetermined temperature which is lower than the rated temperature. Two examples of switching the target resistor 50 are described in detail below.

[0038] 2-2. First example of resistor switching Figure 4 is an explanatory diagram showing a specific example of a vehicle power supply device 1 according to an embodiment. Specifically, in case (A) of Figure 4, an example is shown in which the target resistor 50 is switched at predetermined intervals. For example, consider switching the target resistor 50 in the order of the first resistor 50A, the second resistor 50B, and the third resistor 50C. First, the control device 100 sets the target resistor 50 to the first resistor 50A. That is, it sets one of the multiple resistors 50. In this case, the first switch waveform 101 becomes an ON waveform. On the other hand, the third switch waveform 103 and the fifth switch waveform 105 both become OFF waveforms.

[0039] Next, as shown in case (A) of Figure 4, after a predetermined time has elapsed since setting the target resistor 50 to the first resistor 50A, the control device 100 switches the target resistor 50 from the first resistor 50A to the second resistor 50B. In other words, one of the multiple resistors 50, other than the one resistor 50 mentioned above, is set. In this case, the third switch waveform 103 becomes the ON waveform, and both the first switch waveform 101 and the fifth switch waveform 105 become the OFF waveform. The predetermined time may be, for example, a time determined during evaluation so that the maximum temperature of the switching element corresponding to the target resistor 50 is below a predetermined temperature lower than the rated temperature.

[0040] Furthermore, as shown in case (A) of Figure 4, after a predetermined time has elapsed since switching the target resistor 50 to the second resistor 50B, the control device 100 switches the target resistor 50 from the second resistor 50B to the third resistor 50C. In other words, one resistor 50 other than the two resistors 50 mentioned above is selected from among the multiple resistors 50. In this case, the fifth switch waveform 105 becomes the ON waveform, and both the first switch waveform 101 and the third switch waveform 103 become the OFF waveform.

[0041] Subsequently, the operation of switching the target resistor 50 in the order of the first resistor 50A, the second resistor 50B, and the third resistor 50C is repeatedly performed. After that, if the voltage abnormality is resolved, the control device 100 disconnects the connection between the second inverter 20 and the resistor 50.

[0042] Thus, in the first example of switching the resistor 50 in the vehicle power supply unit 1 according to this embodiment, the target resistor 50 is switched at predetermined intervals. As a result, while the function of the resistor 50 is operated, the temperature of the switching element corresponding to the target resistor 50 is controlled to be below a predetermined temperature, which is lower than the rated temperature. Therefore, it is possible to avoid failure of the switching element corresponding to the target resistor 50.

[0043] 2-3. Second example of resistor switching In the first example of switching the resistor 50 described above, the target resistor 50 is switched at predetermined intervals. On the other hand, in the second example of switching the resistor 50, the target resistor 50 is switched based on the temperature of the switching element corresponding to the target resistor 50. Specifically, the first switching element 21, the third switching element 23, and the fifth switching element 25 are each provided with a temperature sensor (not shown) capable of measuring temperature. In this case, the control device 100 is connected to the temperature sensor and acquires information from the temperature sensor. The waveform of the temperature acquired by the temperature sensor is shown, for example, as in case (B) of Figure 4.

[0044] As shown in case (B) of Figure 4, the waveform of the temperature state acquired by the temperature sensor provided on the first switching element 21 is represented by the first temperature waveform 111, the waveform of the temperature state acquired by the temperature sensor provided on the third switching element 23 is represented by the third temperature waveform 113, and the waveform of the temperature state acquired by the temperature sensor provided on the fifth switching element 25 is represented by the fifth temperature waveform 115.

[0045] Here, we consider switching the target resistor 50 in the order of the first resistor 50A, the second resistor 50B, and the third resistor 50C. First, the control device 100 sets the target resistor 50 to the first resistor 50A. In this case, as shown in case (B) of Figure 4, the temperature shown in the first temperature waveform 111 rises. At this time, since both the third switching element 23 and the fifth switching element 25 are in a non-operating state, the temperatures shown in the third temperature waveform 113 and the fifth temperature waveform 115 are both maintained at room temperature.

[0046] Next, as shown in case (B) of Figure 4, when the temperature shown in the first temperature waveform 111 exceeds a predetermined temperature, the control device 100 switches the target resistor 50 from the first resistor 50A to the second resistor 50B. After switching the target resistor 50 to the second resistor 50B, the first switching element 21 switches from the operating state to the non-operating state, so the temperature shown in the first temperature waveform 111 decreases. On the other hand, the third switching element 23 switches from the non-operating state to the operating state, so the temperature shown in the third temperature waveform 113 increases. Since the fifth switching element 25 is in the non-operating state, the temperature shown in the fifth temperature waveform 115 is maintained at around room temperature. Note that the predetermined temperature is set to a temperature lower than the rated temperature.

[0047] Furthermore, as shown in case (B) of Figure 4, if the temperature shown in the third temperature waveform 113 rises above a predetermined temperature after switching the target resistor 50 to the second resistor 50B, the control device 100 switches the target resistor 50 from the second resistor 50B to the third resistor 50C. After switching the target resistor 50 to the third resistor 50C, the third switching element 23 switches from an operating state to a non-operating state, so the temperature shown in the third temperature waveform 113 decreases. On the other hand, the fifth switching element 25 switches from a non-operating state to an operating state, so the temperature shown in the fifth temperature waveform 115 increases. Since the first switching element 21 remains in a non-operating state, the temperature shown in the first temperature waveform 111 decreases further and returns to around room temperature.

[0048] Subsequently, the operation of switching the target resistor 50 in the order of the first resistor 50A, the second resistor 50B, and the third resistor 50C is repeatedly performed. After that, if the voltage abnormality is resolved, the control device 100 disconnects the connection between the second inverter 20 and the resistor 50.

[0049] Furthermore, the temperature sensor may be provided on the second switching element 22, the fourth switching element 24, and the sixth switching element 26 instead of the first switching element 21, the third switching element 23, and the fifth switching element 25. Also, the temperature sensor may be provided on the resistor 50 instead of the switching element. In this case, the temperature of the switching element may be estimated based on the temperature of the resistor 50. In addition, the predetermined temperature used for determining whether the resistor 50 is switching may be the same or different for the positive electrode switching element and the negative electrode switching element.

[0050] Thus, in the second switching example of the resistor 50 in the vehicle power supply unit 1 according to the embodiment, the target resistor 50 is switched based on the temperature of the switching element corresponding to the target resistor 50. As a result, while the function of the resistor 50 is operated, the temperature of the switching element corresponding to the target resistor 50 is controlled to be below a predetermined temperature lower than the rated temperature. Therefore, it is possible to avoid failure of the switching element corresponding to the target resistor 50.

[0051] Furthermore, the first switching example and the second switching example may be combined as examples of switching the target resistor 50. For example, the control device 100 switches the target resistor 50 when predetermined conditions are met. The predetermined conditions include at least one of the following: a first condition in which the time while one of the multiple resistors 50 is enabled is greater than or equal to a predetermined time, and a second condition in which the temperature of the switching element obtained by the temperature sensor is greater than or equal to a predetermined temperature.

[0052] The following describes a first processing example corresponding to the first switching example of resistor 50, and a second processing example corresponding to the second switching example of resistor 50.

[0053] 3. Processing Example 3-1. First Processing Example Figure 5 is a flowchart showing a first processing example of the vehicle power supply device 1 according to the embodiment.

[0054] In step S100, the control device 100 determines whether the voltage value obtained by the voltage sensor is equal to or greater than a predetermined value. If it is determined that the voltage value is equal to or greater than the predetermined value (step S100; Yes), the process proceeds to step S110. Otherwise (step S100; No), the process ends.

[0055] In step S110, the control device 100 enables the first resistor 50A, which is one of several resistors 50 that are initially disabled as the target resistor 50. The process then proceeds to step S120.

[0056] In step S120, the control device 100 determines whether a predetermined time has elapsed since the first resistor 50A was activated. If it is determined that a predetermined time has elapsed since the first resistor 50A was activated (step S120; Yes), the process proceeds to step S130. Otherwise (step S120; No), the process returns to step S120.

[0057] In step S130, the control device 100 determines whether the voltage value obtained by the voltage sensor is equal to or greater than a predetermined value. If it is determined that the voltage value is equal to or greater than the predetermined value (step S130; Yes), the process proceeds to step S140. Otherwise (step S130; No), the process ends.

[0058] In step S140, the control device 100 disables the first resistor 50A and enables the second resistor 50B. In other words, the control device 100 switches the target resistor 50 from the first resistor 50A to the second resistor 50B. The process then proceeds to step S150.

[0059] In step S150, the control device 100 determines whether a predetermined time has elapsed since the second resistor 50B was activated. If it is determined that a predetermined time has elapsed since the second resistor 50B was activated (step S150; Yes), the process proceeds to step S160. Otherwise (step S150; No), the process returns to step S150.

[0060] In step S160, the control device 100 determines whether the voltage value obtained by the voltage sensor is equal to or greater than a predetermined value. If it is determined that the voltage value is equal to or greater than the predetermined value (step S160; Yes), the process proceeds to step S170. Otherwise (step S160; No), the process ends.

[0061] In step S170, the control device 100 disables the second resistor 50B and enables the third resistor 50C. In other words, the control device 100 switches the target resistor 50 from the second resistor 50B to the third resistor 50C. The process then proceeds to step S180.

[0062] In step S180, the control device 100 determines whether a predetermined time has elapsed since the third resistor 50C was enabled. If it is determined that a predetermined time has elapsed since the third resistor 50C was enabled (step S180; Yes), the process proceeds to step S190. Otherwise (step S180; No), the process returns to step S180.

[0063] In step S190, the control device 100 disables the third resistor 50C.

[0064] 3-2. Second Processing Example Figure 6 is a flowchart showing a second processing example of the vehicle power supply device 1 according to the embodiment. Here, we will explain the processing that differs from the first processing example, and omit the explanation of the processing that overlaps with the first processing example. Specifically, steps S200, S210, S230, S240, S260, S270, and S290, which overlap with the first processing example, correspond to steps S100, S110, S130, S140, S160, S170, and S190, respectively. The processing that differs from the first processing example is steps S220, S250, and S280, and the details of each process will be described later.

[0065] In step S220, the control device 100 determines whether the temperature obtained by the temperature sensor provided on the first switching element 21 corresponding to the positive terminal (+) of the first resistor 50A, or the temperature sensor provided on the fourth switching element 24 corresponding to the negative terminal (-) of the first resistor 50A, is above a predetermined temperature. If it is determined that the temperature is above the predetermined temperature (step S220; Yes), the process proceeds to step S230. Otherwise (step S220; No), the process returns to step S220.

[0066] In step S250, the control device 100 determines whether the temperature obtained by the temperature sensor provided on the third switching element 23 corresponding to the positive terminal (+) of the second resistor 50B, or the temperature sensor provided on the sixth switching element 26 corresponding to the negative terminal (-) of the second resistor 50B, is above a predetermined temperature. If it is determined that the temperature is above the predetermined temperature (step S250; Yes), the process proceeds to step S260. Otherwise (step S250; No), the process returns to step S250.

[0067] In step S280, the control device 100 determines whether the temperature obtained by the temperature sensor provided on the fifth switching element 25 corresponding to the positive terminal (+) of the third resistor 50C, or the temperature sensor provided on the second switching element 22 corresponding to the negative terminal (-) of the third resistor 50C, is above a predetermined temperature. If it is determined that the temperature is above the predetermined temperature (step S280; Yes), the process proceeds to step S290. Otherwise (step S280; No), the process returns to step S280. [Explanation of symbols]

[0068] 1…Vehicle power supply unit, 2…PCS, 3…External device, 4…PCU, 5…Voltage sensor, 6…Capacitor, 7…Positive power line, 8…Negative power line, 10…First inverter, 20…Second inverter, 11,21…First switching element, 12,22…Second switching element, 13,23…Third switching element, 14,24…Fourth switching element, 15,25…Fifth switching element, 16,26…Sixth switching element, 31,41…First power line, 32,42…Second power line, 33,43…Third power line, 50…Resistor, 50A…First resistor, 50B…Second resistor, 50C…Third resistor, 100…Control device, 101…First switch waveform, 103…Third switch waveform 105...5th switch waveform, 111...1st temperature waveform, 113...3rd temperature waveform, 115...5th temperature waveform

Claims

1. The system comprises a PCU and a plurality of resistors connected to the PCU. The aforementioned PCU is A capacitor is installed between the positive power line and the negative power line, A voltage sensor connected to the positive power line and measuring the voltage of the capacitor, A first inverter is connected in parallel to the aforementioned capacitor and is connected to an external device driven by three phases, A second inverter is connected in parallel to the capacitor and is also connected to the plurality of resistors, A control device connected to at least the voltage sensor and the second inverter, Includes, Each of the plurality of resistors is connected to the positive power line via one of the plurality of positive switching elements provided on the positive side of each phase of the second inverter. The negative terminal of each of the plurality of resistors is connected to the negative power line via one of the plurality of negative switching elements provided on the negative side of each phase of the second inverter. The negative terminal is connected to the negative power line via a negative switching element of one of two phases different from the phase on which the positive switching element connected to the positive terminal is provided. The control device is If the voltage value of the voltage sensor is greater than or equal to a predetermined value, the positive switching element corresponding to the positive terminal of one of the plurality of resistors, which is initially inactive, and the negative switching element corresponding to the negative terminal of that resistor are both turned ON. When certain conditions are met, the positive switching element corresponding to the positive terminal of one resistor and the negative switching element corresponding to the negative terminal of one resistor are both turned OFF, while the positive switching element corresponding to the positive terminal of another resistor among the plurality of resistors and the negative switching element corresponding to the negative terminal of that other resistor are both turned ON. A vehicle power supply device characterized by the following features.

2. A vehicle power supply device according to claim 1, The predetermined condition is that the time during which both the positive switching element corresponding to the positive terminal of the resistor and the negative switching element corresponding to the negative terminal of the resistor are turned ON is equal to or greater than a predetermined time. A vehicle power supply device characterized by the following features.

3. A vehicle power supply device according to claim 1, The system further includes a temperature sensor for measuring the temperature of each of the plurality of positive electrode switching elements or the plurality of resistors, The control device is further connected to the temperature sensor, The predetermined conditions include at least one of the following: the condition that the time during which both the positive switching element corresponding to the positive terminal of the resistor and the negative switching element corresponding to the negative terminal of the resistor are turned ON is for a predetermined time or longer; and the condition that the temperature is above a predetermined temperature. A vehicle power supply device characterized by the following features.

4. A vehicle power supply device according to any one of claims 1 to 3, The plurality of positive electrode switching elements are, A first positive electrode switching element provided on the positive electrode side of the first phase, A second positive electrode switching element is provided on the positive electrode side of the second phase, It includes a third positive electrode switching element provided on the positive electrode side of the third phase, The plurality of negative electrode switching elements are, A first negative electrode switching element provided on the negative electrode side of the first phase, A second negative electrode switching element provided on the negative electrode side of the second phase, The system includes a third negative electrode switching element provided on the negative electrode side of the third phase, The aforementioned plurality of resistors are, A first resistor whose positive terminal is connected to a first power line between the first positive switching element and the first negative switching element in the first phase, and whose negative terminal is connected to a second power line between the second positive switching element and the second negative switching element in the second phase, A second resistor having its positive terminal connected to the second power line and its negative terminal connected to the third power line between the third positive switching element and the third negative switching element in the third phase, A third resistor having its positive terminal connected to the third power line and its negative terminal connected to the first power line, The control device is The configuration is such that the first positive switching element corresponding to the positive terminal of the first resistor and the second negative switching element corresponding to the negative terminal of the first resistor are both turned ON, or the second positive switching element corresponding to the positive terminal of the second resistor and the third negative switching element corresponding to the negative terminal of the second resistor are both turned ON, or the third positive switching element corresponding to the positive terminal of the third resistor and the first negative switching element corresponding to the negative terminal of the third resistor are both turned ON. A vehicle power supply device characterized by the following features.

5. If the voltage value of the capacitor included in the PCU is above a predetermined value, both the positive switching element corresponding to the positive terminal of one of the multiple resistors connected to the PCU, which are initially disabled, and the negative switching element corresponding to the negative terminal of the same resistor are turned ON. Based on predetermined conditions, the positive switching element corresponding to the positive terminal of one resistor and the negative switching element corresponding to the negative terminal of one resistor are both turned OFF, while the positive switching element corresponding to the positive terminal of another resistor among the plurality of resistors and the negative switching element corresponding to the negative terminal of that other resistor are both turned ON. including A vehicle power supply method characterized by the following:

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