Power conversion system

Abstract

This prevents the unintended application of voltage from external power sources to electrical equipment connected to the vehicle's power supply port. [Solution] The power conversion system comprises an inlet 108, an outlet 135, a power conversion unit 160, relays 150 and 155, a control unit 170, signal lines SL1 and SL2, and an inverting circuit 165. The power conversion unit 160 charges the energy storage device or converts the power from the energy storage device and supplies it to the outlet 135. The control unit 170 outputs a control signal SG1 for controlling the open / closed state of relays 150 and 155. Signal line SL1 is arranged between relay 150 and the control unit 170. Signal line SL2 branches off from signal line SL1 and is arranged between relay 155 and branch point BP1. The inverting circuit 165 is provided on signal line SL1 between relay 150 and branch point BP1 and outputs an inverted signal SG1a of the control signal SG1.

Description

Technical Field

[0001] The present disclosure relates to a power conversion system.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2015-142409 (Patent Document 1) discloses a vehicle. This vehicle includes an inlet, a charger, a charging relay, a power storage device, a vehicle interior outlet, and a DC (Direct Current) / AC (Alternate Current) inverter. The inlet is a power receiving port that receives power supply power from an external power source. The charger converts the received power supply power and charges the power storage device when the charging relay is in a closed state (external charging). The vehicle interior outlet is a power supply port to which an electrical device is connected. The DC / AC inverter converts the power of the power storage device and supplies the converted power to the power supply port as discharge power (external power supply). The DC / AC inverter operates after it is confirmed that the voltage of its output node is 0V in order to avoid collision between charging power and discharge power.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The vehicle may include a bidirectional power converter capable of performing either an external charging function or an external power supply function with a single unit. In this case, a first switch may be provided on a first power line extending from the power receiving port to the power converter, and a second switch may be provided on a second power line extending from the first power line to the power supply port. During external charging, it is preferable that one of the first and second switches is controlled to be open so that one of the first and second power lines is non-conductive. This is because the voltage of the power supply often differs from the operating voltage of electrical equipment, and the power receiving port and power supply port are electrically connected to prevent the voltage of the power supply from being unintentionally applied to electrical equipment.

[0005] However, one of the switches, which should be controlled to be open during external charging, may be unintentionally closed due to a malfunction in its control system or other factors. As a result, both the first and second power lines may become conductive, and the power receiving port and power supply port may be electrically connected. In this case, the voltage of the power supply may be unintentionally applied to the electrical equipment.

[0006] This disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a power conversion system that can prevent the voltage of power supplied from outside the vehicle from being unintentionally applied to electrical equipment connected to the vehicle's power supply port. [Means for solving the problem]

[0007] The power conversion system of this disclosure is mounted on a vehicle. The power conversion system comprises a power receiving port, a power supply port, a bidirectional power conversion device, a first switch, a second switch, a control device, a first signal line, a second signal line, and an inverting circuit. The power receiving port receives power supplied from an external power supply facility to the vehicle. Electrical equipment is connected to the power supply port. The power conversion device converts the power received by the power receiving port to charge the vehicle's energy storage device, or converts the power from the energy storage device and supplies it to the power supply port. The first switch is provided on a first power line extending from the power receiving port to the power conversion device. The second switch is provided on a second power line extending from the portion of the first power line between the first switch and the power conversion device to the power supply port. The control device outputs control signals for controlling the open / closed states of the first and second switches. The first signal line is provided between one of the first and second switches and the control device. The second signal line branches off from the first signal line at the first branching point and is located between the first switch and the other switch of the second switch and the first branching point. The inverting circuit is located on the first signal line between one of the switches and the branching point and outputs an inverted signal of the control signal. [Effects of the Invention]

[0008] According to this disclosure, it is possible to prevent the voltage of power supplied from outside the vehicle from being unintentionally applied to electrical equipment connected to the vehicle's power supply port. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram of a vehicle equipped with a power conversion system according to an embodiment. [Figure 2] This is a diagram illustrating the detailed configuration of the charging and power supply unit. [Figure 3] This diagram illustrates the relationship between signal level Lv1, the open / closed state of the relay, and signal levels Lv2 and Lv3, assuming that the charging and supplying unit is functioning normally without any abnormalities. [Figure 4] This is a flowchart illustrating an example of processing performed by a control device. [Figure 5]This is a flowchart illustrating another example of processing by a control device. [Figure 6] This is an overall configuration diagram of a vehicle equipped with a power conversion system according to Modification Example 2. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and their descriptions will not be repeated.

[0011] Figure 1 is an overall configuration diagram of a vehicle equipped with a power conversion system according to an embodiment. Referring to Figure 1, the vehicle 10 includes a battery 105, an inlet 108, a charge / discharge relay 110, an inverter 115, and an SMR (System Main Relay) 120. The vehicle 10 further includes an outlet 135, a charging / supplying unit 140, and a vehicle ECU (Electronic Control Unit) 145.

[0012] Battery 105 is a high-voltage energy storage device that stores power for the vehicle 10 to run, and is a rechargeable secondary battery such as a lithium-ion battery.

[0013] Inlet 108 is connected to a power supply facility 20 outside the vehicle 10 and is a power receiving port that receives power supplied from the power supply facility 20. The power supply facility 20 is connected to a power grid PG. The power supplied may be either AC power or DC power.

[0014] The charge / discharge relay 110 is connected between power lines PLa and PLb. The inverter 115 drives the vehicle 10's traction motor (not shown). The SMR 120 is connected between power lines PLb and PLc. The charge / discharge relay 110 and the SMR 120 are closed, for example, when the power supply is DC power or grid power (described later).

[0015] The socket 135 is installed in the passenger compartment of the vehicle 10, and the electrical device 30 is connected thereto. The electrical device 30 is an electrical device different from the components of the vehicle 10, and is, for example, a household electrical appliance that operates by receiving 100V AC power from the socket 135.

[0016] The charging unit 140 includes relays 150, 155, a power conversion unit 160, an inversion circuit 165, and a control unit 170.

[0017] The relay 150 is, for example, a normally open contact relay (a-contact relay), and corresponds to a switch connected between the power lines PL1a and PL1b. The power line PL1a is a power line branched from the power line PLa at the branch point P1. The relay 150 is provided for performing external charging or system power supply (both will be described later). The relay 155 is a normally open contact relay, and corresponds to a switch connected between the power lines PL2a and PL2b. The power line PL2a is a power line branched from the power line PL1b at the branch point P2. The relay 155 is provided for performing normal power supply (to be described later).

[0018] Each of the relays 150 and 155 is opened and closed according to the voltage applied to its coil (not shown). For example, for each relay, when the voltage applied to its coil exceeds the operating voltage of the relay, the relay is closed, and when the applied voltage is lower than the return voltage of the relay, the relay is opened. In the embodiment, it is assumed that the operating voltage and the return voltage of the relays 150 and 155 are the same. The return voltage is higher than zero voltage (0V) and lower than the operating voltage.

[0019] The power conversion unit 160 is a bidirectional power conversion device and is connected between the power lines PL1b and PL1c. The power line PL1c is a power line branched from the power line PLc at the branch point P3. When the relay 150 is in the closed state, the power conversion unit 160 converts the power received by the inlet 108 and charges the battery 105 (external charging). Alternatively, when the relay 155 is in the closed state, the power conversion unit 160 converts the power of the battery 105 (or the DC power supplied from the power supply equipment 20 through the charge / discharge relay 110 and the SMR 120) and supplies it to the outlet 135. Thereby, the electrical device 30 is powered by the converted power.

[0020] Power supply from the vehicle 10 to the outside thereof is also referred to as "external power supply". External power supply when the power supply target is the power grid PG is also referred to as "grid power supply". External power supply when the power supply target is the electrical device 30 is also referred to as "normal power supply". During normal power supply, it is preferable that the relay 150 is controlled to be in the open state and the relay 155 is controlled to be in the closed state. The same applies when normal power supply is performed during grid power supply. Thus, the power conversion unit 160 can execute either external charging or external power supply with a single unit.

[0021] The power line extending from the inlet 108 to the power conversion unit 160 is also referred to as the "first power line". The first power line corresponds to the portion of the power line PLa between the inlet 108 and the branch point P1, the power lines PL1a and PL1b, and the power transmission path formed by the relay 150. The power line extending from the power line PL1b (specifically, the branch point P2) to the outlet 135 is also referred to as the "second power line". The second power line corresponds to the power transmission path formed by the power lines PL2a and PL2b and the relay 155. The power line extending from the inlet 108 to the battery 105 is also referred to as the "third power line". The third power line corresponds to the power transmission path formed by the power lines PLa, PLb, PLc, the charge / discharge relay 110, and the SMR 120.

[0022] The control unit 170 is a control circuit that controls the relays 150 and 155 and the power conversion unit 160. The control unit 170 performs external charge control to control external charging. External charge control includes generating control signals (described later) to control the open / closed states of the relays 150 and 155 and activating the power conversion unit 160. In this case, the relays 150 and 155 are controlled to be in the closed and open states, respectively, and the power conversion unit 160 is controlled to convert the supplied power. The inverting circuit 165 will be explained in detail later.

[0023] The vehicle ECU 145 is a higher-level ECU than the control unit 170 and controls the charge / discharge relay 110, SMR 120, and charge / supply unit 140. The vehicle ECU 145 and the control unit 170 monitor each other's status. For example, the vehicle ECU 145 can determine whether the control unit 170 is functioning correctly based on the results of monitoring the control unit 170. The vehicle ECU 145 and the control unit 170 are also referred to as the "control device 180".

[0024] The vehicle ECU 145 can communicate with the power supply equipment 20 via CAN (Controller Area Network) communication or the like. The vehicle ECU 145 performs external charging control by generating control commands such as a power supply start command INS1 or a power supply stop command INS2 and transmitting them to the power supply equipment 20. In this case, the external charging control further includes transmitting the power supply start command INS1 after closing the charge / discharge relay 110 and SMR 120, and opening the charge / discharge relay 110 and SMR 120 after transmitting the power supply stop command INS2.

[0025] The inlet 108, charge / discharge relay 110, SMR 120, outlet 135, charging / supplying unit 140, and vehicle ECU 145 are examples of the “power conversion system” of this disclosure. The same applies to the modified examples 1 and 2 described later.

[0026] During external charging, it is preferable that one of the relays 150 and 155 is controlled to be open so that one of the first power line and the second power line is in a non-conductive state. This is because the voltage of the power supply is often different from the operating voltage of the electrical equipment 30, and this prevents the inlet 108 and the outlet 135 from being electrically connected and the voltage of the power supply being unintentionally applied to the electrical equipment 30.

[0027] For example, when power supply (DC power) is supplied to the battery 105 through the charge / discharge relay 110 and SMR 120, it is preferable that relay 150 is controlled to be open in order to close relay 155 and perform normal power supply. Alternatively, when relay 150 is controlled to be closed and power supply is supplied to the power conversion unit 160, and the power converted by the power conversion unit 160 is supplied to the battery 105, it is preferable that relay 155 is controlled to be open.

[0028] However, one of the relays, which should be controlled to be open during external charging, may be unintentionally closed due to a malfunction in the control system, such as the control unit 170, or in the signal transmission path. As a result, both the first and second power lines may become conductive, and the inlet 108 and the outlet 135 may be electrically connected. In this case, the voltage of the power supply may be unintentionally applied to the electrical equipment 30, which is undesirable. Even when normal power supply is performed during grid power supply with the charge / discharge relays 110 and SMR 120 controlled to be closed, it is undesirable for the voltage of the battery 105 to be unintentionally applied to the electrical equipment 30.

[0029] In contrast, the charging and discharging unit 140 according to this embodiment has a configuration that addresses such problems. This point will be explained in detail below.

[0030] Figure 2 is a diagram illustrating the detailed configuration of the charging and supplying unit 140. Referring to Figure 2, the charging and supplying unit 140 includes relays 150 and 155, a control unit 170, signal lines SL1 to SL4, and an inverting circuit 165.

[0031] The control unit 170 includes a processing circuit 171 and an input / output interface 172. The processing circuit 171 includes a CPU (Central Processing Unit) 173 and a memory 174. The CPU 172 executes various arithmetic operations by reading programs stored in the memory 174. As a result, the processing circuit 171 generates a control signal SG1 for controlling the open / closed state of relays 150 and 155. Information indicating the output level of the control signal SG1 (details described later) is stored in the memory 174.

[0032] The input / output interface 172 includes an output terminal 176 and input terminals 177 and 178. The control signal SG1 is output from output terminal 176. Output terminal 176 and input terminals 177 and 178 are connected to signal lines SL1, SL3, and SL4, respectively.

[0033] The control signal SG1 is a voltage signal for controlling the open / closed state of relays 150 and 155. The level (output level) of the control signal SG1 output from output terminal 176 is also referred to as signal level Lv1. Signal level Lv1 is either a logic high (H) level or a logic low (L) level. Signal level Lv1 is stored in the output buffer of the control unit 170 in memory 174. Signal level Lv1 corresponds to an example of the "first signal level" in this disclosure. In this example, when signal level Lv1 is at the H level, the voltage applied to the coil of relay 155 is equal to or greater than the operating voltage, so relay 155 is controlled to the closed state. On the other hand, when signal level Lv1 is at the L level, the voltage applied to the coil of relay 155 is less than the return voltage, so relay 155 is controlled to the open state. Signal line SL1 is arranged between relay 150 and output terminal 176, forming a signal path from control unit 170 to relay 150.

[0034] The inverting circuit 165 is provided on the signal line SL1 and outputs the inverted signal SG1a of the control signal SG1. The inverted signal SG1a has a signal level Lva, which is different from the signal level Lv1. For example, if the signal level Lv1 is high, the signal level Lva is low. On the other hand, if the signal level Lv1 is low, the signal level Lva is high. The inverted signal SG1a is transmitted from the output terminal of the inverting circuit 165 to the coil of the relay 150 via the signal line SL1a. The signal line SL1a is the portion of the signal line SL1 between the output terminal of the inverting circuit 165 and the relay 150. When the signal level Lva is high, the voltage applied to the coil of the relay 150 is greater than or equal to the operating voltage, so the relay 150 is controlled to the closed state. On the other hand, when the signal level Lva is low, the voltage applied to the coil of the relay 150 is less than the return voltage, so the relay 150 is controlled to the open state.

[0035] Signal line SL2 branches off from signal line SL1b at branching point BP1 and is located between relay 155 and branching point BP1. Signal line SL1b corresponds to the portion of signal line SL1 between the input terminal and output terminal 176 of the inverting circuit 165. Control signal SG1 is transmitted through signal line SL1b. Control signal SG1 is transmitted not only to the input terminal of the inverting circuit 165 but also to the coil of relay 155 via signal line SL2 from signal line SL1b.

[0036] Signal line SL3 branches off from signal line SL1a at branch point BP2 and is located between branch point BP2 and input terminal 177. Signal SG2 is transmitted through signal line SL3. Signal SG2 corresponds to the input signal input from signal line SL1a through signal line SL3 to input terminal 177. Signal SG2 has a signal level Lv2. Signal level Lv2 is either a high level or a low level and is the same as signal level Lva. Signal level Lv2 corresponds to an example of the "second signal level" in this disclosure. Unless there is an abnormality such as a break in signal line SL1a, signal SG2 is the same as the inverted signal SG1a. In this case, unless there is an abnormality in the inverting circuit 165, signal level Lv2 is different from signal level Lv1.

[0037] Signal line SL4 branches off from signal line SL1b at branch point BP3 and is located between branch point BP3 and input terminal 178. Signal SG3 is transmitted through signal line SL4. Signal SG3 corresponds to the input signal that is input from signal line SL1b through signal line SL4 to input terminal 178. Signal SG3 has a signal level Lv3, which is either high or low. Unless there is a break in signal line SL1b (specifically, the portion of signal line SL1b between branch point BP3 and output terminal 176), signal SG3 is the same as control signal SG1, and therefore signal level Lv3 is equal to signal level Lv1.

[0038] According to the above configuration of the charging and supplying unit 140, the control signal SG1 is transmitted to relay 155, while the inverting signal SG1a is transmitted to relay 150. As a result, the open and closed states of relays 150 and 155 are controlled complementaryly to each other according to a single control signal SG1 output from the same control circuit (control unit 170). Consequently, even if the control signal SG1 changes unintentionally due to some abnormality and one of relays 150 or 155 (the relay that should be controlled to be in the open state) is closed, the other switch of these relays is opened. Therefore, a situation in which these relays are closed simultaneously is avoided. Thus, it is possible to prevent the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 135 during external charging. As a result, the electrical equipment 30 can be properly protected from the voltage of the power supply. Even if some abnormality occurs when normal power supply is performed during grid power supply, the situation in which relays 150 and 155 are closed simultaneously is avoided for the same reasons as above. Therefore, the electrical equipment 30 can be properly protected.

[0039] The processing circuit 171 of the control unit 170 can determine whether there is an abnormality in the charging and supplying unit 140 (for example, an abnormality in the inverting circuit 165 or the signal line SL1) according to the signal levels Lv1, Lv2, and Lv3. This determination process is also called the "abnormality determination process". For example, in the abnormality determination process, the control unit 170 determines that there is no abnormality if (a) signal level Lv1 is equal to signal level Lv3 and signal level Lv1 is different from signal level Lv2. On the other hand, the control unit 170 determines that there is an abnormality if (b) signal level Lv1 is different from signal level Lv3, or (c) signal level Lv1 is equal to signal level Lv3 and signal level Lv1 is equal to signal level Lv2. The abnormality determination process is performed, for example, during external charging, grid power supply, or normal power supply.

[0040] If the inverting circuit 165 or signal line SL1 is in an abnormal state, the signal level Lv2 may become the same as the signal level Lv1. Therefore, the signal level Lv2 may reflect an abnormality in the inverting circuit 165 or signal line SL1. Thus, the abnormality detection process can appropriately determine whether or not there is an abnormality in the inverting circuit 165 or signal line SL1.

[0041] For example, if both signal levels Lv1 and Lv2 are at the H level, both relays 150 and 155 may be in the closed state. On the other hand, the control unit 170 can perform appropriate processing if it determines that there is an abnormality during the abnormality detection process. As a result, it is possible to avoid a situation in which both relays 150 and 155 unintentionally become closed.

[0042] The appropriate processing described above is, for example, the control unit 170 setting the signal level Lv1 so that the control signal SG1 instructs the relay 155 to open (in this example, switching from H level to L level). As a result, the relay 155 is opened, and the electrical equipment 30 can be isolated from the power supply equipment 20. Consequently, external charging can continue while preventing the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 135.

[0043] The appropriate processing described above may also involve notifying the vehicle ECU 145 of the determination that an abnormality has occurred. In response to this notification, the vehicle ECU 145 transmits a power supply stop command INS2 to the power supply equipment 20. As a result, the supply of power from the power supply equipment 20 to the inlet 108 is stopped. As a result, normal power supply can be carried out while preventing the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 135.

[0044] For example, if the control unit 170 is unable to output the control signal SG1 normally due to an internal malfunction (for example, if the signal level Lv1 stored in the output buffer is different from the output level of the control signal SG1 actually output from the output terminal 176), then the signal level Lv3 may differ from the signal level Lv1. Therefore, it is also possible to determine whether there is an internal malfunction or an abnormality in the signal line SL1b (specifically, the portion between the branch point BP3 and the output terminal 176) according to the signal levels Lv1 and Lv3. For example, if the control unit 170 determines that there is an abnormality when the signal level Lv1 and the signal level Lv3 are different, the control unit 170 may notify the vehicle ECU 145 of the determination that there is an abnormality. On the other hand, if the signal level Lv1 and the signal level Lv3 are equal, the control unit 170 determines that there is no abnormality.

[0045] Figure 3 illustrates the relationship between signal level Lv1, the open / closed states of relays 150 and 155, and signal levels Lv2 and Lv3, assuming that the charging / supplying unit 140 is functioning normally without any abnormalities.

[0046] Referring to Figure 3, if signal level Lv1 is at H level, then under normal circumstances, signal level Lva is assumed to be at L level. Therefore, relays 150 and 155 are assumed to be in the open and closed states, respectively. Then, signal level Lv2 is assumed to be equal to signal level Lva (and different from signal level Lv1), and is therefore assumed to be at L level. On the other hand, signal level Lv3 is assumed to be equal to signal level Lv1, and is therefore assumed to be at H level.

[0047] Therefore, the control unit 170 can determine that there is no abnormality in the charging and supplying unit 140 when signal level Lv1 is at the H level and signal levels Lv2 and Lv3 are at the L and H levels, respectively. On the other hand, when signal level Lv2 is at the H level or signal level Lv3 is at the L level, the control unit 170 can determine that such an abnormality exists.

[0048] On the other hand, if signal level Lv1 is L level, then under normal circumstances, signal level Lva is assumed to be H level. Therefore, relays 150 and 155 are assumed to be closed and open, respectively. Then, signal level Lv2 is assumed to be H level because it is equal to signal level Lva (and different from signal level Lv1). On the other hand, signal level Lv3 is assumed to be L level because it is equal to signal level Lv1.

[0049] Therefore, the control unit 170 can determine that there is no abnormality in the charging and supplying unit 140 when signal level Lv1 is L level and signal levels Lv2 and Lv3 are H level and L level, respectively. On the other hand, when signal level Lv2 is L level or signal level Lv3 is H level, the control unit 170 can determine that such an abnormality exists.

[0050] Figure 4 is a flowchart illustrating an example of processing by the control device 180. Referring to Figure 4, this flowchart is executed, for example, at predetermined time intervals during external charging. Hereafter, steps will be abbreviated as "S".

[0051] The vehicle ECU 145 determines whether the control unit 170 is functioning correctly (S5). If the control unit 170 is malfunctioning (NO in S5), the vehicle ECU 145 sends a power supply stop command INS2 to the power supply equipment 20 (S10). After that, the process shifts to return.

[0052] If the control unit 170 is functioning normally (YES in S5), the control unit 170 performs an abnormality detection process (S20). In this example, S20 is executed as S22 to S28 below.

[0053] The control unit 170 determines whether signal level Lv1 is equal to signal level Lv3 (S22). If signal level Lv1 is different from signal level Lv3 (NO in S22), the process proceeds to S28. On the other hand, if signal level Lv1 is equal to signal level Lv3 (YES in S22), the process proceeds to S24.

[0054] The control unit 170 determines whether signal level Lv1 is different from signal level Lv2 (S24). If signal level Lv1 is different from signal level Lv2 (YES in S24), the control unit 170 determines that there is no abnormality in the charging / supplying unit 140 (S26). After that, the process shifts to return. If signal level Lv1 is equal to signal level Lv2 (NO in S24), the process proceeds to S28.

[0055] The control unit 170 determines that there is an abnormality in the charging and supplying unit 140 (S28). For example, if signal level Lv1 is different from signal level Lv3 (NO in S22), the control unit 170 determines that there is an internal abnormality or an abnormality in signal line SL1b (specifically, the portion between branch point BP3 and output terminal 176). Alternatively, if signal level Lv1 is equal to signal level Lv2 (NO in S24), it determines that there is an abnormality in the inverting circuit 165 or signal line SL1. The control unit 170 may also notify the vehicle ECU 145 of the abnormality determination result in S28. In this case, the vehicle ECU 145 sends a power supply stop command INS2 to the power supply equipment 20.

[0056] The control unit 170 sets the signal level Lv1 (for example, to L level) so that the control signal SG1 instructs the relay 155 to open (S30). After that, the process shifts to return. In the above, under the assumption that there is no internal malfunction of the control unit 170 or a malfunction of the signal line SL1b, S22 may be omitted. In this case, an abnormality detection process is performed according to the signal levels Lv1 and Lv2, and after S5, the process proceeds to S24.

[0057] As described above, according to this embodiment, even if one of the relays 150 or 155 is closed due to an unintended change in the control signal SG1, the other relay will be opened. Therefore, a situation in which both relays are closed simultaneously is avoided. Thus, it is possible to prevent the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 135.

[0058] [Example 1] Signal levels Lv2 and Lv3 may fluctuate suddenly due to noise or other causes. In this case, it is undesirable for the abnormality detection process to incorrectly determine that there is an abnormality in the charging / power supply unit 140, even though there is actually no abnormality.

[0059] Therefore, in the abnormality determination process, the control unit 170 may determine that there is an abnormality in the charging and supplying unit 140 only if a predetermined mismatch occurs between signal levels Lv1, Lv2, and Lv3 (mismatch state) and this mismatch state continues for a predetermined time or longer. For example, the control unit 170 counts the time that this mismatch state continues from the time the mismatch state starts (in one example, when both signal levels Lv2 and Lv3 become H level), and executes the abnormality determination process if the counted time exceeds the predetermined time. The mismatch state may be, for example, a state in which signal level Lv1 is different from signal level Lv3 (NO in S22 of Figure 4), or a state in which signal level Lv1 is equal to signal level Lv2 (NO in S24 of Figure 4).

[0060] By performing the abnormality detection process as described above, even if the signal levels Lv2 and Lv3 fluctuate, if the duration of the mismatch is less than a predetermined time, it is prevented from being incorrectly determined as abnormal. Therefore, the aforementioned erroneous detection in the abnormality detection process can be avoided.

[0061] Figure 5 is a flowchart illustrating another example of processing by the control device 180. Referring to Figure 5, this flowchart is the same as the flowchart of the embodiment (Figure 4), except that S20 further includes S27. Therefore, a detailed explanation will not be repeated.

[0062] If signal level Lv1 is different from signal level Lv3 (NO in S22), or if signal level Lv1 is equal to signal level Lv2 (NO in S24), the control unit 170 determines whether the mismatch has continued for a predetermined time or longer (S27). If the mismatch has not continued for a predetermined time or longer (NO in S27), the process returns to S22. In this case, S22, S24, and S27 may be repeated. If the mismatch has continued for a predetermined time or longer (YES in S27), the control unit 170 determines that there is an abnormality in the charging and supplying unit 140 (S28). In this example as well, S22 may be omitted, as in the embodiment. In this case, the mismatch is a state where signal level Lv1 is equal to signal level Lv2.

[0063] As described above, this modified example 1 makes it possible to avoid misjudgments in the abnormality detection process caused by sudden fluctuations in signal levels Lv2 and Lv3.

[0064] [Differentiation 2] In the above description, the inverting circuit 165 is provided between the branching point BP1 and the relay 150, but it may also be provided between the branching point BP1 and the relay 155.

[0065] Figure 6 is an overall configuration diagram of a vehicle equipped with a power conversion system according to this modified example 2. Referring to Figure 6, the charging and supplying unit 142 differs from the charging and supplying unit 140 (Figures 1 and 2) in the location of the inverting circuit 165 and signal lines SL1, SL2, and SL3. Specifically, (1) the signal line SL1 on which the inverting circuit 165 is provided is located between the relay 155 and the output terminal 176. (2) The signal line SL2 branches off from the signal line SL1 at branching point BP1 and is located between the relay 150 and branching point BP1. (3) The signal line SL3 branches off from the signal line SL1a at branching point BP2 and is located between the input terminal 177 and branching point BP2. Aside from (1) to (3), the charging and supplying unit 142 is basically the same as the charging and supplying unit 140. Therefore, a detailed explanation will not be repeated.

[0066] In this modified example 2, the control signal SG1 is transmitted to relay 150, while the inverted signal SG1a is transmitted to relay 155. As a result, the open and closed states of relays 150 and 155 are controlled complementaryly to each other according to a single control signal SG1 output from the same control circuit (control unit 170). Consequently, the situation in which these relays are closed simultaneously is avoided. Therefore, it is possible to prevent the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 135 during external charging. Even when normal power supply is performed during grid power supply, the electrical equipment 30 can be properly protected for the same reasons as described above.

[0067] The control unit 170 performs abnormality determination processing according to signal levels Lv1, Lv2, and Lv3. For example, in case (a) above, it is determined that there is no abnormality in the charging and supplying unit 140, and in case (b) or (c) above, it is determined that there is an abnormality. The control unit 170 may also determine that there is an abnormality only if the inconsistent state as state (b) or (c) continues for a predetermined time or longer.

[0068] In this modified example 2, the abnormality detection process can be performed during external charging, grid power supply, or normal power supply. For example, if the control unit 170 determines that there is an abnormality, it sets the signal level Lv1 to H level so that the control signal SG1 instructs the relay 155 to open. Alternatively, if such a determination is made, the control unit 170 may notify the vehicle ECU 145 of this fact, and the vehicle ECU 145 may send a power supply stop command INS2 to the power supply equipment 20.

[0069] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0070] 10 Vehicle, 20 Power supply equipment, 30 Electrical equipment, 105 Battery, 108 Inlet, 110 Charge / discharge relay, 135 Outlet, 140, 142 Charge / power supply unit, 145 Vehicle ECU, 150, 155 Relay, 160 Power conversion unit, 165 Inverting circuit, 170 Control unit, 180 Control device.

Claims

1. A power conversion system installed in a vehicle, The vehicle has a power receiving port for receiving power supplied from an external power supply facility, A power outlet to which electrical equipment is connected, A bidirectional power converter that converts the power received by the power receiving port to charge the vehicle's energy storage device, or converts the power from the energy storage device to supply it to the power supply port, A first switch is provided on the first power line extending from the power receiving port to the power conversion device, A second switch is provided on a second power line that extends from the portion of the first power line between the first switch and the power converter to the power supply port, A control device that outputs control signals for controlling the open / closed states of the first switch and the second switch, A first signal line is provided between one of the first and second switches and the control device, A second signal line branches off from the first signal line at the first branching point and is arranged between the first switch and the other switch of the second switch and the first branching point, A power conversion system comprising a first signal line and an inverting circuit provided between the one switch and the first branching point, which outputs an inverted signal of the control signal.

2. The device further comprises a third signal line branched from the portion of the first signal line between the output terminal of the inverting circuit and the one switch, The control device is The first input terminal connected to the third signal line, The processing circuit includes a first signal level stored in the output buffer of the control device as the level of the control signal output from the output terminal of the control device, and a second signal level indicating the level of the signal input to the first input terminal through the third signal line, which determines whether or not there is an abnormality in the signal path from the control device to one of the switches. The aforementioned determination process is: If the first signal level is different from the second signal level, a first process is performed to determine that there is no abnormality. The power conversion system according to claim 1, further comprising a second process of determining that an abnormality exists when the first signal level is equal to the second signal level.

3. The power conversion system according to claim 2, wherein the second process is performed only when the state in which the first signal level is equal to the second signal level continues for a predetermined period of time or longer.

4. The system further comprises a fourth signal line that branches off from the portion of the first signal line between the first branching point and the output terminal, The control device further includes a second input terminal connected to the fourth signal line, The determination process is performed according to the first signal level, the second signal level, and the third signal level indicating the level of the signal input to the second input terminal through the fourth signal line. The first process is performed when the first signal level is equal to the third signal level and the first signal level is different from the second signal level. The power conversion system according to claim 2, wherein the second process is performed when the first signal level is different from the third signal level, or when the first signal level is equal to the third signal level and the first signal level is equal to the second signal level.

5. The control device is configured to control external charging, which uses the power received by the power receiving port to charge the energy storage device. The control device is During the external charging, the determination process is executed. The power conversion system according to any one of claims 2 to 4, wherein, if the determination process determines that the above-mentioned abnormality exists, the first signal level is set so that the control signal instructs the opening of the second switch.

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