Power conversion system

Abstract

Even in the event of a malfunction in the vehicle's control system, this prevents the unintended application of external power voltage to electrical equipment connected to the vehicle's power supply port. [Solution] The power conversion system 110 comprises an inlet 107, an outlet 108, a power conversion device 120, electrical contacts 142 and 162, and a control device 170. The power conversion device 120 converts the power received by the inlet 107 to charge the battery 105, or converts the power from the battery 105 to supply to the outlet 108. Electrical contact 142 is provided on a first power line extending from the inlet 107 to the power conversion device 120. Electrical contact 162 is provided on a second power line extending from power lines PL1b and PL2b to the outlet 108 and is opened and closed complementaryly with electrical contact 132. The control device 170 generates a control signal CS1 to control the operating state of both electrical contacts 132 and 152.

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 power outlet, and a DC (Direct Current) / AC (Alternate Current) inverter. The inlet is a power receiving port that receives power supply 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 power 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. The DC / AC inverter operates after it is confirmed that the voltage of its output node is 0V in order to avoid collision between the charging power and the 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 a power supply function to an external source. 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 to control the first switch to a closed state in order to keep the first power line conductive, while controlling the second switch to an open state in order to deconduct the second power line. 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, if a malfunction occurs in the control system that controls the second switch, the second switch may malfunction and close unintentionally during external charging. As a result, both the first and second power lines may become conductive, potentially electrically connecting the power receiving port and the power supply port. 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, even if a malfunction occurs in the vehicle's control system. [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, and a control device. The power receiving port receives power supplied from outside 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, and is opened and closed complementary to the first switch. The control device generates a first control signal for controlling the operating state of both the first switch and the second switch. [Effects of the Invention]

[0008] According to this disclosure, even if a malfunction occurs in the vehicle's control system, 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 an overall configuration diagram of a vehicle equipped with a power conversion system according to an embodiment. [Figure 3] This is an overall configuration diagram of a vehicle equipped with a power conversion system according to an embodiment. [Figure 4] This is an overall configuration diagram of a vehicle equipped with a power conversion system according to an embodiment. [Figure 5] This diagram illustrates an example of the transition between the signal value of a control signal and the open / closed state of a contact relay. [Figure 6] This diagram illustrates another example of the signal value of a control signal and the transition of the open / closed state of a contact relay. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described in detail below with reference to the drawings. The same or corresponding parts in the drawings will be denoted by the same reference numerals and their descriptions will not be repeated. Each embodiment and its modifications may be combined with one another as appropriate.

[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 107, an outlet 108, and a power conversion system 110.

[0012] Battery 105 is an energy storage device that stores power for the vehicle 10 to run, and is a rechargeable secondary battery such as a lithium-ion battery. The amount of charge stored in battery 105 is expressed, for example, by SOC (State of Charge).

[0013] Inlet 107 is a power receiving port that receives power supplied from an external power supply facility 20 of the vehicle 10 through its charging cable 205 and connector 210. Inlet 107 outputs a signal PISW. Signal PISW indicates the connection status (connected / disconnected) between connector 210 and inlet 107. The power supply may be either AC power or DC power. If the power supply is AC power, its voltage is, for example, 200V. If the power supply is DC power, its voltage is, for example, 400V or 800V.

[0014] The outlet 108 is installed inside the vehicle 10, and electrical equipment 30 is connected to it. Electrical equipment 30 is electrical equipment different from the components of vehicle 10, and is, for example, a household appliance that operates on 100V AC power.

[0015] The power conversion system 110 is connected to the battery 105. The power conversion system 110 includes a power conversion device 120, relay circuits 125 and 127, and a control device 170.

[0016] The power conversion device 120 is a bidirectional power conversion device. When the contact relays 130 and 140 (described later) are in the closed state, the power conversion device 120 converts the power received by the inlet 107 and charges the battery 105 (external charging). Alternatively, when the contact relays 150 and 160 (described later) are in the closed state, the power conversion device 120 converts the power of the battery 105 and supplies it to the outlet 108. Thereby, the converted power is supplied to the electrical equipment 30 through the outlet 108. Power supply from the vehicle 10 to the outside thereof (in this example, the electrical equipment 30) is also referred to as "external power supply". Thus, the power conversion device 120 can perform either external charging or external power supply with a single unit.

[0017] The relay circuit 125 includes the contact relays 130 and 150. The contact relay 130 includes an electrical contact 132 and a coil 134. The electrical contact 132 corresponds to a switch connected between the power lines PL1a and PL1b. The contact relay 150 includes an electrical contact 152 and a coil 154. The electrical contact 152 corresponds to a switch connected between the power lines PL3a and PL3b. The coil 154 is connected to the coil 134. The power line PL3b branches from the power line PL1b at the branch point BP1.

[0018] The relay circuit 127 includes the contact relays 140 and 160. The contact relay 140 includes an electrical contact 142 and a coil 144. The electrical contact 142 corresponds to a switch connected between the power lines PL2a and PL2b. The electrical contact 142 is provided electrically in parallel with the electrical contact 132 on the first power line (described later). The contact relay 160 includes an electrical contact 162 and a coil 164. The electrical contact 162 corresponds to a switch connected between the power lines PL4a and PL4b. The electrical contact 162 is provided electrically in parallel with the electrical contact 152 on the second power line (described later). The coil 164 is connected to the coil 144. The power line PL4b branches from the power line PL2b at the branch point BP2.

[0019] Each of the contact relays 130, 140, 150, and 160 further includes an iron core (not shown) wound around its coil. Each of the contact relays 130 and 140 is a normally open contact relay (a-contact relay). Each of the contact relays 150 and 160 is a normally closed contact relay (b-contact relay).

[0020] The electrical contacts 132, 142, 152, and 162 are turned on and off according to the applied voltage to the coils 134, 144, 154, and 164, respectively. For example, for the contact relay 130 (150), when the applied voltage to the coil 134 (154) exceeds the operating voltage of the contact relay 130 (150), the electrical contact 132 (152) is turned on (off), and when this applied voltage is lower than the return voltage of the contact relay 130 (150), the electrical contact 132 is turned off (on). The same applies to the contact relays 140 and 160. In the following description, it is assumed that the operating voltages of the contact relays 130, 140, 150, and 160 are the same, and the return voltages of these contact relays are the same. The return voltage is higher than zero voltage (0V) and lower than the operating voltage.

[0021] In the following description, the "open state" of the contact relays 130, 140, 150, and 160 means the state in which the electrical contacts 132, 142, 152, and 162 are turned off, respectively. The "closed state" of the contact relays 130, 140, 150, and 160 means the state in which the electrical contacts 132, 142, 152, and 162 are turned on, respectively. During external charging, it is preferable that the contact relays 130 and 140 are controlled to be in the closed state, and the contact relays 150 and 160 are controlled to be in the open state.

[0022] To "release" the contact relays 130, 140, 150, and 160 means to switch these contact relays from the closed state to the open state, respectively. To "close" the contact relays 130, 140, 150, and 160 means to switch these contact relays from the open state to the closed state, respectively.

[0023] Driving contact relays 130 and 140 (normally open type contact relays) means switching their open / closed state from the open state to the closed state, respectively. The open state of contact relays 130 and 140 corresponds to the state in which these relays are not driven (non-driven state). The closed state of contact relays 130 and 140 corresponds to the state in which these relays are driven (driven state). The non-driven state and the driven state are collectively referred to as the "operating state".

[0024] Driving contact relays 150 and 160 (normally closed contact relays) means switching their open / closed state from the closed state to the open state, respectively. The closed state of contact relays 150 and 160 corresponds to the non-driven state of these relays. The open state of contact relays 150 and 160 corresponds to the driven state of these relays.

[0025] The power line extending from the inlet 107 to the power converter 120 is also referred to as the "first power line." The first power line corresponds to a power transmission path formed by power lines PL1a, PL2a, contact relays 130, 140, and power lines PL1b, PL2b.

[0026] The power lines extending from power lines PL1b and PL2b to outlet 108 within the first power line are also referred to as the "second power line." The second power line corresponds to the power transmission path formed by power lines PL3a and PL4a, contact relays 150 and 160, and power lines PL3b and PL4b.

[0027] The control device 170 has terminal pairs 172 and 174. Terminal pair 172 is connected to relay circuit 127. Terminal pair 174 is connected to relay circuit 125.

[0028] The control device 170 controls various devices of the vehicle 10. For example, the control device 170 controls the power converter 120. The control device 170 controls the open / closed state of contact relays 140 and 160 by generating a control signal CS1. The control device 170 controls the open / closed state of contact relays 130 and 150 by generating a control signal CS2.

[0029] The control signal CS1 is a voltage signal whose signal value is the voltage applied to terminal pair 172. Due to the control signal CS1, voltage is applied to coils 144 and 164, respectively. The signal value of the control signal CS1 switches between a logic high (H) level and a logic low (L) level.

[0030] When this signal value is at the H level, the voltage applied to coils 144 and 164 is higher than the operating voltage of contact relays 140 and 160, respectively. For example, when the control signal CS1 switches from the L level to the H level, the voltage applied to coils 144 and 164 exceeds the operating voltage of contact relays 140 and 160, respectively. As a result, the operating state of these contact relays switches from the non-driven state to the driven state, causing contact relay 140 to close and contact relay 160 to open.

[0031] On the other hand, when the signal value of the control signal CS1 is at the L level, the voltage applied to coils 144 and 164 is lower than the return voltage of contact relays 140 and 160, respectively. For example, when the control signal CS1 switches from the H level to the L level, the voltage applied to coils 144 and 164 falls below the return voltage of contact relays 140 and 160, respectively. As a result, the operating state of these contact relays switches from the driven state to the non-driven state, causing contact relay 140 to open and contact relay 160 to close.

[0032] Thus, the control signal CS1 is a signal that controls the operating state of both contact relays 140 and 160 by itself. In other words, the operating states of contact relays 140 and 160 are controlled simultaneously in the same relay circuit 127 according to a single control signal CS1. As a result, contact relays 140 and 160 open and close complementaryly to each other in response to the switching of the signal value of control signal CS1.

[0033] The control signal CS2 is a voltage signal whose signal value is the voltage applied to terminal pair 174. Due to the control signal CS2, a voltage is applied to each of the coils 134 and 154. The signal value of the control signal CS2 switches between high and low levels.

[0034] When this signal value is at the H level, the voltage applied to coils 134 and 154 is higher than the operating voltage of contact relays 130 and 150, respectively. For example, when the control signal CS2 switches from the L level to the H level, the voltage applied to coils 134 and 154 exceeds the operating voltage of contact relays 130 and 150, respectively. As a result, the operating state of these contact relays switches from the non-driven state to the driven state, causing contact relay 130 to close and contact relay 150 to open.

[0035] On the other hand, when the signal value of the control signal CS2 is at the L level, the voltage applied to coils 134 and 154 is lower than the return voltage of contact relays 130 and 150, respectively. For example, when the control signal CS2 switches from the H level to the L level, the voltage applied to coils 134 and 154 falls below the return voltage of contact relays 130 and 150. As a result, the operating state of these contact relays switches from the driven state to the non-driven state, causing contact relay 130 to open and contact relay 150 to close.

[0036] Thus, the control signal CS2 is a signal that controls the operating state of both contact relays 130 and 150 by itself. In other words, the operating states of contact relays 130 and 150 are controlled simultaneously in the same relay circuit 125 according to a single control signal CS2. As a result, contact relays 130 and 150 open and close complementaryly to each other in response to the switching of the signal value of the control signal CS2.

[0037] When the connector 210 is connected to the inlet 107, the control device 170 can communicate with the power supply equipment 20 via CAN (Controller Area Network) communication or the like. For example, the control device 170 generates a power supply start request RQ1 and sends it to the power supply equipment 20. As a result, power is supplied from the power supply equipment 20 to the vehicle 10, and external charging begins. During external charging, the control device 170 basically controls the control signals CS1 and CS2 to the H level to keep the first power line conductive and controls the contact relays 130 and 140 to the closed state. When the State of Charge (SOC) of the battery 105 reaches a predetermined target value (for example, 80%), the control device 170 generates a power supply stop request RQ2 and sends it to the power supply equipment 20. As a result, the supply of power from the power supply equipment 20 to the vehicle 10 is stopped, and external charging ends.

[0038] During external charging, it is preferable to control the contact relays 130 and 140 to the closed state in order to keep the first power line conductive, and to control the contact relays 150 and 160 to the open state in order to keep the second power line non-conductive. This is because the voltage of the power supplied from the power supply equipment 20 is different from the operating voltage of the electrical equipment 30, and this prevents the voltage of the power supplied from the power supply equipment 30 from being unintentionally applied to the electrical equipment 30 when the connector 210 is electrically connected to the outlet 108.

[0039] An unintended malfunction may occur in the control system that controls the contact relays 150 and 160. It is undesirable that, as a result of such a malfunction, at least one of the contact relays 150 and 160 may malfunction and unintentionally close during external charging. In this case, both the first and second power lines may become conductive, and the connector 210 and the outlet 108 may be electrically connected. As a result, the voltage of the power supply may be unintentionally applied to the electrical equipment 30. In that case, it may not be possible to protect the electrical equipment 30 from the voltage of the power supply.

[0040] In contrast, the power conversion system 110 according to this embodiment can address such problems. This point will be explained below.

[0041] Figures 2 to 5 illustrate an example of the transitions in the signal values ​​of control signals CS1 and CS2, and the open / closed states of contact relays 130, 140, 150, and 160.

[0042] Referring to Figure 2, at time t0, the control device 170 determines, based on the signal PISW, that the connector 210 is connected to the inlet 107. The signal values ​​of the control signals CS1 and CS2 are both at the L level.

[0043] Subsequently, at time t1, the control device 170 switches the signal value of the control signal CS1 from L level to H level. As a result, the voltage applied to coils 144 and 164 exceeds the operating voltage of contact relays 140 and 160. Consequently, the operating state of these contact relays switches from a non-driven state to a driven state. Therefore, contact relay 140 closes while contact relay 160 opens (see Figure 3).

[0044] At time t1, the control device 170 also switches the control signal CS2 from L level to H level. As a result, the voltage applied to coils 134 and 154 exceeds the operating voltage of contact relays 130 and 150. Consequently, the operating state of these contact relays switches from non-driven to driven. Therefore, contact relay 130 closes while contact relay 150 opens (see Figure 3).

[0045] At time ts, the control device 170 starts external charging by sending a power supply start request RQ1 to the power supply equipment 20. As a result, power is supplied to the power converter 120 with contact relays 130 and 140 in the closed state and contact relays 150 and 160 in the open state. Consequently, external charging is performed while ensuring electrical isolation between the connector 210 and the outlet 108 (see Figure 4). When the SOC reaches the target value at time tf, the control device 170 terminates external charging by sending a power supply stop request RQ2 to the power supply equipment 20.

[0046] At time t2, the control device 170 switches the signal value of the control signal CS1 from high level to low level. As a result, the voltage applied to coils 144 and 164 falls below the return voltage of contact relays 140 and 160. Consequently, the operating state of these contact relays switches from the driven state to the non-driven state. Therefore, contact relay 140 is opened while contact relay 160 is closed.

[0047] At time t2, the control device 170 also switches the signal value of the control signal CS2 from H level to L level. As a result, the voltage applied to coils 134 and 154 falls below the return voltage of contact relays 130 and 150. Consequently, the operating state of these contact relays switches from the driven state to the non-driven state. Therefore, contact relay 130 opens while contact relay 150 closes.

[0048] Referring to Figure 5, in this example, at time tc before the SOC reaches the target value during external charging, the signal values ​​of control signals CS1 and CS2 unintentionally change from H level to L level due to a malfunction in the control device 170. As a result, contact relays 150 and 160 are unintentionally closed. However, even in such a case, contact relay 130 opens in response to the change in the signal value of control signal CS2, and contact relay 140 opens in response to the change in the signal value of control signal CS1.

[0049] Thus, even in the event of a malfunction in the control device 170, the open / closed states of the contact relays 140 and 160 switch complementaryly to each other according to a single control signal CS1, and the open / closed states of the contact relays 130 and 150 also switch complementaryly to each other according to a single control signal CS2. Therefore, the situation in which the contact relays 130, 140, 150, and 160 simultaneously close during external charging is avoided. Consequently, even if a malfunction of the control device 170 occurs unintentionally during external charging, it is possible to prevent the voltage of the power supply from being applied to the electrical equipment 30 through the outlet 108. Therefore, the electrical equipment 30 can be properly protected from the voltage of the power supply.

[0050] The control device 170 can also protect the electrical equipment 30 by generating only one of the control signals CS1 or CS2 to control the contact relays 130, 150 or 140, 160 (details will be described later), but in this embodiment, the signal values ​​of the control signals CS1 and CS2 are set in conjunction as described above. For example, if the control device 170 sets the signal value of control signal CS1 to an H level so that the contact relays 140, 160 are driven, it sets the signal value of control signal CS2 to an H level so that the contact relays 130, 150 are also driven. Alternatively, if the control device 170 sets the signal value of control signal CS1 to an L level so that the contact relays 140, 160 are not driven, it sets the signal value of control signal CS2 to an L level so that the contact relays 130, 150 are also not driven.

[0051] As described above, by setting the signal values ​​in conjunction, even if both of the contact relays 140 or 160 are closed due to welding of at least one of them, the contact relays 130 and 150 will open and close complementaryly in response to the control signal CS2. This prevents all of the contact relays 130, 140, 150, and 160 from being closed simultaneously because one of the contact relays 130 or 150 is in the open state.

[0052] Alternatively, by setting the signal values ​​in conjunction as described above, even if both of the contact relays 130 and 150 are closed due to welding of at least one of them, the contact relays 140 and 160 will open and close complementaryly in response to the control signal CS1. This prevents all of the contact relays 130, 140, 150, and 160 from being closed simultaneously because one of the contact relays 140 or 160 is in the open state.

[0053] Therefore, in this embodiment, even if any of the contact relays 130, 140, 150, or 160 are welded together, the connector 210 and the outlet 108 can be effectively insulated during external charging. Consequently, the electrical equipment 30 can be effectively protected from the voltage of the power supply.

[0054] As described above, according to this embodiment, even if the signal values ​​of the control signals CS1 and CS2 change due to a malfunction of the control device 170 during external charging, it is possible to prevent the voltage of the power supply from being unintentionally applied to the electrical equipment 30 through the outlet 108. As a result, the electrical equipment 30 can be properly protected from the voltage of the power supply during external charging.

[0055] [Example 1] In this embodiment, the operating times of each of the contact relays 130, 140, 150, and 160 are not considered. The operating time of a contact relay refers to the time from when a voltage higher than the operating voltage of the contact relay (e.g., the rated voltage) is applied to the coil of the contact relay until the contact relay is driven. However, in practice, it is preferable to consider the operating time of each contact relay, and this operating time depends on the configuration of the contact relay. For example, the thicker the iron core of the coil of a contact relay, the shorter the operating time of that contact relay.

[0056] In this modified example 1, the contact relays 150 and 160 (normally closed contact relays) are configured such that their operating time is shorter than that of the contact relays 130 and 140 (normally open contact relays). For example, the iron cores of the contact relays 150 and 160 are thicker than the iron cores of the contact relays 130 and 140, respectively.

[0057] Figure 6 illustrates another example of the signal values ​​of control signals CS1 and CS2, and the transition of the open / closed states of contact relays 130, 140, 150, and 160. The times t0, t1, t2, ts, and tf are the same as those shown in Figure 2.

[0058] Referring to Figure 6, the operating time Δa is the operating time of contact relays 130 and 140. The operating time Δb is the operating time of contact relays 150 and 160.

[0059] Time t1a is a time that is Δa later than time t1. At time t1a, contact relays 130 and 140 are driven and closed. Time t1b is a time that is Δb later than time t1. At time t1b, contact relays 150 and 160 are driven and opened.

[0060] The operating time Δb is shorter than the operating time Δa. As a result, after both signal values ​​of control signals CS1 and CS2 are switched from L level to H level at time t1, contact relays 150 and 160 are driven and opened earlier than contact relays 130 and 140 (time t1b). Thus, during the period Tab from time t1b to time t1a, all contact relays 130, 140, 150, and 160 are in the open state. Then, after contact relays 130 and 140 are driven and closed at time t1a, external charging begins. Therefore, external charging begins after the connector 210 and outlet 108 are more reliably electrically isolated. As a result, the voltage of the power supply is more effectively prevented from being applied to the electrical equipment 30. Thus, the electrical equipment 30 can be more appropriately protected from the voltage of the power supply. Note that after time t2, external charging has already finished and no external voltage is applied to the first power line. Therefore, there is no problem even if contact relays 150 and 160 close earlier than contact relays 130 and 140 after time t2.

[0061] According to this modified example 1, even if the signal values ​​of the control signals CS1 and CS2 change unintentionally before the start of external charging, the contact relays 150 and 160 are driven and opened earlier than the contact relays 130 and 140. As a result, the situation in which all of the contact relays 130, 140, 150, and 160 remain open continues for some time before the contact relays 130 and 140 are closed. Therefore, even if the signal values ​​of the control signals CS1 and CS2 change unintentionally before the start of external charging, the connector 210 and the outlet 108 are more effectively isolated, and the electrical equipment 30 can be properly protected from the voltage of the power supply.

[0062] [Differentiation 2] In the above, (1) each of the contact relays 130 and 140 is a normally open type contact relay, and each of the contact relays 150 and 160 is a normally closed type contact relay. In contrast, (2) each of the contact relays 130 and 140 is a normally closed type contact relay, and each of the contact relays 150 and 160 is a normally open type contact relay.

[0063] Thus, it is sufficient that one of the contact relays 130, 140 and the other of the contact relays 150, 160 is a normally open type contact relay and the other is a normally closed type contact relay. As a result, in both cases (1) and (2), the contact relays 140, 160 open and close complementaryly to each other in response to changes in the signal value of the control signal CS1, and the contact relays 130, 150 open and close complementaryly to each other in response to changes in the signal value of the control signal CS2.

[0064] In case (2), the control device 170 sets both the signal values ​​of control signals CS1 and CS2 to the L level when external charging is performed. As a result, external charging is performed with contact relays 130 and 140 in the closed state and contact relays 150 and 160 in the open state. Consequently, the electrical equipment 30 can be properly protected from the voltage of the power supply when external charging is performed. In addition, even if the signal values ​​of control signals CS1 and CS2 change unintentionally when external charging is performed, contact relays 140 and 160 open and close complementaryly in response to the change in the signal value of control signal CS1, and contact relays 130 and 150 open and close complementaryly in response to the change in the signal value of control signal CS2. Therefore, the situation in which contact relays 130, 140, 150, and 160 are all closed at the same time is avoided. Thus, as in the embodiment, it is possible to prevent the voltage of the power supply from being unintentionally applied to the electrical equipment 30 when external charging is performed.

[0065] Modifications 1 and 2 may be combined as appropriate. For example, in case (2), the contact relays 130 and 140 (normally closed contact relays) may be configured such that their operating time is shorter than that of the contact relays 150 and 160 (normally open contact relays).

[0066] [Difference 3] Referring again to Figure 1, in the above description, the power conversion system 110 includes both relay circuits 125 and 127, but it may include only one of these contact relay circuits. In this case, the control device 170 generates only one of the control signals CS1 and CS2.

[0067] For example, if the power conversion system 110 includes only relay circuit 125 among relay circuits 125 and 127, the control device 170 generates only control signal CS2 among control signals CS1 and CS2. Then, when external charging starts, the control device 170 switches the signal value of control signal CS2 from L level to H level. As a result, contact relay 130 is closed while contact relay 150 is opened. Consequently, external charging is performed with contact relay 130 in the closed state and contact relay 150 in the open state.

[0068] Alternatively, if the power conversion system 110 includes only relay circuit 127 (Figure 1) among relay circuits 125 and 127, the control device 170 generates only control signal CS1 among control signals CS1 and CS2. Then, when external charging starts, the control device 170 switches the signal value of control signal CS1 from L level to H level. As a result, contact relay 140 is driven to close, while contact relay 160 is driven to open. Consequently, external charging is performed with contact relay 140 in the closed state and contact relay 160 in the open state.

[0069] In this modified example 3, the contact relays 130 and 150 are controlled in the same relay circuit 125 according to a single control signal CS2, preventing them from simultaneously closing. Alternatively, the contact relays 140 and 160 are controlled in the same relay circuit 127 according to a single control signal CS1, preventing them from simultaneously closing. As a result, even if the signal value of control signal CS1 or CS2 changes unintentionally during external charging, the voltage of the power supply is prevented from being unintentionally applied to the electrical equipment 30 through the outlet 108. Thus, according to this modified example 3, the number of components in the power conversion system 110 can be reduced while adequately protecting the electrical equipment 30 from the voltage of the power supply during external charging.

[0070] 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]

[0071] 1,2,3 Modified examples; 10 Vehicle; 20 Power supply equipment; 30 Electrical equipment; 105 Battery; 107 Inlet; 108 Outlet; 110 Power conversion system; 120 Power conversion device; 125,127 Relay circuit; 130,140,150,160 Contact relay; 170 Control device.

Claims

1. A power conversion system installed in a vehicle, A power receiving port for receiving power supplied from outside the vehicle, 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, and which opens and closes in a complementary manner to the first switch. A power conversion system comprising a control device that generates a first control signal for controlling the operating state of both the first switch and the second switch.

2. One of the first switch and the second switch is a first contact relay as a normally open type contact relay, The power conversion system according to claim 1, wherein the other of the first switch and the second switch is a second contact relay as a normally closed contact relay.

3. The power conversion system according to claim 2, wherein the second contact relay is configured such that its operating time is shorter than that of the first contact relay.

4. The first switch is the first contact relay, The power conversion system according to claim 2, wherein the second switch is the second contact relay.

5. A third switch is electrically connected in parallel with the first switch to the first power line, The second power line further includes a fourth switch that is electrically connected in parallel with the second switch and opens and closes complementaryly with the third switch, If the first switch is the first contact relay and the second switch is the second contact relay, The third switch is a normally open type contact relay, different from the first contact relay, and The fourth switch is a normally closed type contact relay, distinct from the second contact relay, and If the first switch is the second contact relay, and the second switch is the first contact relay, The aforementioned third switch is the aforementioned fourth contact relay, The fourth switch is the third contact relay, The control device further generates a second control signal for controlling the operating state of both the third contact relay and the fourth contact relay, The control device is When setting the signal value of the first control signal so that both the first contact relay and the second contact relay are driven, set the signal value of the second control signal so that both the third contact relay and the fourth contact relay are driven. The power conversion system according to any one of claims 2 to 4, wherein when the signal value of the first control signal is set so that neither the first contact relay nor the second contact relay is driven, the signal value of the second control signal is set so that neither the third contact relay nor the fourth contact relay is driven.

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