JP2021085733A - Abnormality determining device - Google Patents

Abstract

To provide an abnormality determining device which can appropriately detect the abnormality of a switch circuit.SOLUTION: Provided is a control device 21 applied to a first switch circuit SW1 provided in an electricity conducting path L1, and determining the abnormality of the switch circuit. The control device comprises: a setting unit which when on/off of the first switch circuit SW1 is switched, sets whether the switching is from an on state to an off state or from an off state to an on state and sets the sequence of on/off switching of two first switching elements 30A, 30B and two second switching elements 30C, 30D on the basis of a current direction at the switching time; a current acquisition unit for acquiring a current flowing through a switch being an abnormality determination object when on/off of each switching element 30 is switched in accordance with the switching sequence; and an abnormality determination unit for carrying out the abnormality determination of a circuit unit being the abnormality determination object, on the basis of the acquisition current acquired by the current acquisition unit.SELECTED DRAWING: Figure 3

Description

The present invention relates to an abnormality determination device for a switch circuit provided in an energization path.

In recent years, in a power supply circuit that supplies electric power from a storage battery to an electric device, the current flowing between the storage battery and the electric device tends to increase. For example, in Patent Document 1, the current flowing in each phase path between the inverter and the three-phase motor is detected, and the current is controlled from the inverter to the three-phase motor. A current sensor is provided in the path of each phase, but it is necessary to use a current sensor having a large rating as the current increases. However, using a current sensor with a large rating leads to an increase in cost. Therefore, in order to use a current sensor with a low rating instead of a current sensor with a high rating, the paths of each phase are branched and parallel. A current sensor is provided in each branch path arranged in parallel, and the current of each phase is calculated based on the values of these current sensors.

JP-A-2018-77132

By the way, not only the current sensor but also the switch circuit that controls the energization of the power supply circuit needs to cope with the increase in current. Therefore, in the energization path in which the switch circuit is provided, the energization path may be branched so that the semiconductor switchings constituting the switch circuit are parallel to each other. Further, in order to suppress the flow of dark current by the diode included in the semiconductor switching element, a semiconductor switching element in which the directions of the diodes are opposite to each other may be directly connected to each branch passage. Then, in each branch path, it is necessary to detect whether or not an abnormality has occurred in the semiconductor switching element. Therefore, each branch path is provided with a current sensor that detects the current flowing through the semiconductor switching element.

In each branch passage in which two semiconductor switching elements and a current sensor are connected in series, when the switch circuit is on, for example, one of the semiconductor switching elements in the parallel branch path has an off abnormality (switching element in one branch path). Current may flow in the switch circuit even if the off abnormality is occurring. Further, in the off state of the switch circuit, for example, even if an on abnormality occurs in one of the semiconductor switching elements in the parallel branch path (on abnormality of the semiconductor switching element in one branch path), no current flows in the switch circuit. Sometimes. Therefore, when determining an off abnormality or an on abnormality of each semiconductor switching element based on the current flowing through the switch circuit, there is a concern that the abnormality determination becomes difficult.

The present invention has been made in view of the above problems, and a main object thereof is to provide an abnormality determination device capable of appropriately detecting an abnormality in a switch circuit.

The first means is an abnormality determination device that is applied to a switch circuit provided in an energization path and determines an abnormality in the switch circuit. The switch circuits are provided in parallel with each other in a first path and a second path. A first circuit having a path and connecting two first switching elements having diodes connected in parallel in the first path in series so that the diodes are opposite to each other. A second circuit unit is provided, and in the second path, two second switching elements having diodes connected in parallel are connected in series so that the diodes are opposite to each other. Is provided, and when the switch circuit is switched on and off, whether the switching is from the on state to the off state or from the off state to the on state, and the current at the time of the switching. A setting unit that sets the on / off switching order of the two first switching elements and the two second switching elements based on the orientation, and a case where the on / off of each switching element is switched according to the switching order. In addition, based on the current acquisition unit that acquires the current flowing through the circuit unit that is the target of abnormality determination among the first circuit unit and the second circuit unit, and the acquisition current acquired by the current acquisition unit, the first It includes a circuit unit and an abnormality determination unit that performs abnormality determination of the circuit unit to be an abnormality determination target among the second circuit units.

The parallel first circuit section and the second circuit section provided in the switch circuit are composed of two switching elements each having a diode connected in parallel. In such a configuration, even if an off abnormality (off abnormality of the switching element of one switch) occurs on either the first switch side or the second switch side in the on state of the switch circuit, the current is applied to the switch circuit. May flow. Further, in the off state of the switch circuit, for example, even if an on abnormality occurs on either the first circuit portion side or the second circuit portion side (on abnormality of the switching element of one circuit portion), a current is applied to the switch circuit. It may not flow. Therefore, when determining an off abnormality or an on abnormality of each switching element based on the current flowing through the switch circuit, there is a concern that the abnormality determination becomes difficult.

In the above configuration, when the switch circuit is switched on and off, whether the switching is from the on state to the off state or from the off state to the on state (first condition) and at the time of the switching. The on / off switching order of the two first switching elements and the two second switching elements is set based on the direction of the current (second condition). In this case, by determining the on / off switching order of each switching element according to each of these conditions, it is possible to appropriately grasp the current change caused by the abnormality of the switching element. Then, when the on / off of each switching element is switched according to the switching order, the abnormality determination of the switch circuit is performed by performing the abnormality determination of at least one of the first circuit unit and the second circuit unit based on the acquired current. Can be carried out properly.

In the second means, when the first circuit unit is targeted for abnormality determination, the setting unit is a switching element in which the diode of the two first switching elements in the first circuit unit is in the energization forward direction. The switching order is set so that the on / off of the forward element is switched in a state where the reverse element, which is a switching element in which the diode is energized in the opposite direction, is on.

In a configuration having two switching elements in which diodes are connected in opposite directions, the energized state does not change depending on the switching order of the switching elements. Therefore, one of the switching elements becomes a forward element and the other switching element becomes a reverse element according to the direction of the current when the switch circuit is switched on and off. Then, as the switching order of each switching element, an order is set so that the on / off of the forward element can be switched while the reverse element is on. As a result, the forward element is switched on and off while the current is flowing in the path, and the path resistance of the path changes. Then, it is possible to determine the abnormality of the forward element depending on whether or not a current change occurs as the forward element is turned on or off.

In the third means, the setting unit switches the on / off of the forward element in a state where the second path is energized when the first circuit unit is targeted for abnormality determination. The switching order is set.

The on / off of the forward element of the first circuit unit, which is the target of abnormality determination, is the state in which the reverse element of the first circuit unit is on, that is, the state in which the first path is energized and the second path is on. The switching order is set so that switching can be performed while the power is on. That is, the switching order is set so that the on / off of the forward element of the first circuit unit can be switched while both the first path and the second path are energized. In a state where both the first path and the second path are energized, the first path and the second path flow at a predetermined diversion ratio. In this state, when the forward element is switched on and off, the path resistance of the first path is changed, so that the diversion ratio of the first path and the second path changes. Therefore, the current change becomes remarkable as compared with the case where the forward element is switched on and off when the second path is not energized, and the current change due to the on or off of the forward element when the first path is energized. It is possible to more reliably determine the abnormality of the forward element depending on whether or not the above occurs.

In the fourth means, when switching from the off state to the on state of the switch circuit, one of the two switching elements in the first circuit unit is first turned on, and the switching is accompanied by the on switching. A current determination unit that determines the direction of the current when the state of the switch circuit is switched is provided based on a change in the current flowing through the switch circuit, and the current determination unit determines the current flowing through the switch circuit when the switch circuit is switched on. When there is a change, it is determined that the current flows in the direction in which the switching element that has been turned on is on the upstream side of energization, and when there is no change in the current flowing through the switch circuit, the switching element that has been turned on is switched. It is determined that the current flows in the direction in which is on the downstream side of the current.

When switching from the off state to the on state, the direction of the current may not be known in advance. In such a case, one of the two switching elements in the first circuit section is switched on, and if there is a change in the current accordingly, the current is directed toward the upstream side of the energized switching element. Judged to flow. On the other hand, when there is no change in the current, it is determined that the current flows in the direction in which the switched element turned on is on the downstream side of the energization. As a result, even if the direction of the current cannot be grasped in advance when switching from the off state to the on state, the direction of the current can be grasped, and the on / off of each switching element is based on the grasped direction of the current. By defining the switching order of, the current change caused by the abnormality of the switching element can be properly grasped.

In the fifth means, the first circuit section and the second circuit section are configured by connecting the anodes of the diodes connected in parallel to the switching elements in series so as to face each other. At least one of one end side and the other end side of the circuit is a power supply side terminal connected to the power supply unit, and an intermediate voltage between the two switching elements is applied in each of the first circuit unit and the second circuit unit. It is provided with an intermediate voltage acquisition unit to be acquired, and is a switching element on the power supply side terminal side of each of the two switching elements in the first circuit unit or the second circuit unit when the switch circuit is switched on and off. When the power supply side element is switched on and off, and the current acquired by the current acquisition unit and the intermediate voltage do not change at that time, it is determined that an abnormality has occurred in the power supply side element.

When the anodes of the diodes connected in parallel to each switching element are connected in series so as to face each other, the intermediate voltage becomes zero when each switching element is off, and the power supply side. When the element is turned on, the voltage value corresponds to the power supply voltage. Further, even when the power supply side element is turned on and the intermediate voltage changes, the acquisition current does not change when the power supply side element is on the downstream side of energization.

Therefore, when the switch circuit is switched on and off, the power supply side element is switched on and off. If neither the acquisition current nor the intermediate voltage changes even if the power supply side element is switched on and off, it is determined that the power supply side element has an abnormality not on the energized downstream side but on the power supply side element. Thereby, when the acquisition current does not change even if the power supply side element is turned on, it is possible to determine whether the power supply side element is on the downstream side of energization or whether an abnormality has occurred in the power supply side element. Therefore, the direction of the current can be correctly grasped, and by determining the on / off switching order of each switching element based on the grasped direction of the current, the current change caused by the abnormality of the switching element can be properly grasped. it can.

In the sixth means, one of the two switching elements in each circuit unit is a forward-direction element which is the switching element in which the diode is in the energization forward direction, and the other is a forward-direction element in which the diode is in the energization reverse direction. This is a reverse direction element, which is the switching element, and the setting unit is in the forward direction on the path side in which the energized state is obtained when only one of the first path and the second path is energized. The switching order is set so that the element is turned off.

When the on / off of each switching element is switched according to the switching order instead of switching all the switching elements from on to off or from off to on at the same time, the current is applied to only one of the first path and the second path. There will be a period of flow. Further, when only one path is energized and each switching element in the energized path is turned on, the path resistance of only the on resistance of each switching element is low, and the current is applied to one path. May be concentrated.

Therefore, when only one of the first path and the second path is energized, the switching order is set so that the forward element is turned off on the passage side where the energized state is established. Specifically, when switching the switch circuit from the off state to the on state, the forward element is turned off in the path that is energized before both the first path and the second path are energized. With this, the reverse element is turned on, and the switching order is set so that both the first path and the second path are transferred to the energized state under that state. When switching the switch circuit from the on state to the off state, after turning off the forward element of one of the first path and the second path, the other path is cut off and only one path is used. Is energized, and then the switching order is set so as to block the one path.

As a result, when the reverse element is turned on in one of the first path and the second path, the forward element is turned off and a current flows through the diode. Therefore, the path resistance is high when the current is flowing in one path, and it is possible to suppress the concentration of the current in the state where the path resistance is low in one path, and it is possible to suppress the large current from flowing in each switching element. it can.

The seventh means has a temperature acquisition unit that acquires the temperatures of the first circuit unit and the second circuit unit, respectively, and the setting unit has the first circuit unit based on the temperature of each circuit unit. The switching order of the switching element is set so that one of the path and the second path is energized.

When the on / off of each switching element is switched according to the switching order instead of switching all the switching elements from on to off or from off to on at the same time, the current is applied to only one of the first path and the second path. There will be a period of flow. During the period when current flows only in one path, the temperature of that path tends to rise.

Therefore, the temperature of each circuit unit is acquired, and the switching order of the switching elements is set so that one of the first path and the second path is energized based on the temperature. As a result, it is possible to suppress the flow of current only in the path provided with the circuit portion having the higher temperature. Therefore, it is possible to suppress an increase in the temperature of only the switching element of one of the circuit units.

In the eighth means, when the first circuit unit is targeted for abnormality determination and the on / off of each switching element is switched according to the switching order, the voltage at a predetermined position of the first path is acquired. The current acquisition unit acquires the detected value of the current sensor provided on the first path as the acquisition current, and the abnormality determination unit obtains the detection value according to the switching order. When the on / off of each switching element is switched, if there is no change in the acquired current and there is a change in the voltage at the predetermined position of the first path, it is determined that the current sensor is abnormal.

Even if there is no change in the current when switching on / off of each switching element, it may be an abnormality of the current sensor rather than an abnormality of each switching element. For example, when the switch is switched from off to on and an abnormality occurs in a reverse element whose diode is in the reverse direction of energization, no current flows in the first path and the acquired current does not change. On the other hand, even if an abnormality does not occur in the reverse element and an abnormality occurs in the current sensor, the acquired current does not change. In such a case, if it is determined that each switching element is abnormal and the fail-safe process is performed, the fail-safe process may be excessive if the current sensor is actually abnormal.

Therefore, when the switch circuit is switched on and off, the voltage at a predetermined position of the first path provided with the first circuit unit to be detected is acquired. The voltage at a predetermined position in the first path changes as the first switching element is switched on and off. As a result, when there is no change in the acquired current by switching the first switching element on and off and a change in the voltage at a predetermined position is detected, it can be determined that the current sensor is abnormal. Therefore, it is possible to prevent the fail-safe process from becoming excessive in the case of an abnormality of the current sensor.

The ninth means has a first power supply and a second power supply, which are connected in parallel to the electric device by the current-carrying path, and in the power-carrying path, the first power supply is used as the switch circuit. It is applied to a power supply system in which a first switch circuit is provided in a first energization path connected to the second power supply and a second switch circuit is provided in a second energization path connected to the second power supply. And when switching the switch circuit to be turned on in the second switch circuit, an overlapping period is provided in which both switch circuits are temporarily turned on, and the current acquisition unit is provided with the current acquisition unit during the overlapping period. When the on / off of each of the switching elements is switched according to the switching order, the current flowing through the circuit unit to be determined for abnormality is acquired, and the abnormality determination unit is acquired by the current acquisition unit during the overlapping period. Based on the acquired current obtained, the abnormality determination of the circuit unit to be the abnormality determination target is performed.

Electric power is supplied to the electric device from the first storage battery and the second storage battery, and when the power supply source is switched between the first storage battery and the second storage battery, the power failure does not occur. An overlapping period is provided in which the 1-switch circuit and the 2nd switch circuit are turned on. During this overlapping period, an abnormality determination of the switch is performed. Therefore, when an abnormality is found in each circuit unit, it is possible to execute a fail-safe process so as not to cause a power failure, such as stopping the switching of the switch circuit that is turned on.

Schematic configuration diagram of the power supply system of this embodiment Schematic configuration of the first switch circuit Explanatory drawing for explaining the switching order of a switching element Time chart when switching the 1st switch circuit from the on state to the off state Time chart when switching the 1st switch circuit from the on state to the off state Time chart when switching the 1st switch circuit from the off state to the on state Time chart when switching the 1st switch circuit from the off state to the on state Time chart when switching the 1st switch circuit from the off state to the on state Time chart when switching the 1st switch circuit from the off state to the on state Flow chart for switching the first switch circuit Flow chart of abnormality judgment processing Time chart when switching the 1st switch circuit from the on state to the off state Time chart when switching the 1st switch circuit from the off state to the on state

<Embodiment>
Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the present embodiment, in a vehicle traveling with an engine (internal combustion engine) as a drive source, it is embodied as an abnormality determination device (control device) used in an in-vehicle power supply system that supplies electric power to various devices of the vehicle.

As shown in FIG. 1, the power supply system S includes a lead storage battery 11 and a lithium ion storage battery 12. The storage batteries 11 and 12 can supply power to the starter 13, the rotary electric machine 15, and various electric loads 14 and 16. Further, each of the storage batteries 11 and 12 can be charged by the rotary electric machine 15. In the present embodiment, the lead-acid battery 11 corresponds to the "power supply unit" and the "first power source", the lithium ion storage battery 12 corresponds to the "power supply unit" and the "second power source", and the rotary electric machine 15 corresponds to the "electric device". Corresponds to.

The lead storage battery 11 is a well-known general-purpose storage battery. On the other hand, the lithium ion storage battery 12 is a high-density storage battery having a smaller power loss during charging / discharging, a higher output density, and a higher energy density than the lead storage battery 11. The lithium ion storage battery 12 is preferably a storage battery having higher energy efficiency during charging / discharging than the lead storage battery 11. Further, the lithium ion storage battery 12 is configured as an assembled battery each having a plurality of cell cells. The rated voltage of each of these storage batteries 11 and 12 is the same, for example, 12V.

The lithium ion storage battery 12 is housed in a storage case and is configured as a battery unit U integrated with a substrate. In FIG. 1, the battery unit U is shown surrounded by a broken line. The battery unit U has external terminals P0, P1, and P2, of which the lead-acid battery 11, the starter 13, and the electric load 14 are connected to the external terminal P1 via wiring, and the external terminal P2 is connected to the external terminal P2 via wiring. The rotary electric machine 15 is connected, and the electric load 16 is connected to the external terminal P3 via wiring. The external terminal P1 is connected to the lead-acid battery 11 via a fuse 17, and the external terminal P3 is connected to the electric load 16 via a fuse 18.

The electric load 14 is a general electric load other than the constant voltage required load. Specific examples of the electric load 14 include a seat heater, a heater for a defroster of a rear window, a headlight, a wiper of a front window, a blower fan of an air conditioner, and the like.

The rotary electric machine 15 is a generator with a motor function having a three-phase AC motor and an inverter as a power conversion device, and is configured as an ISG (Integrated Starter Generator) integrated with mechanical and electrical equipment. The rotary electric machine 15 has a power generation function of generating power (regenerative power generation) by rotating the engine output shaft and the axle, and a power running function of applying a rotational force to the engine output shaft. The power running function of the rotary electric machine 15 makes it possible to apply a rotational force to the engine when the engine that is automatically stopped is restarted during idling stop. Further, the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the rotary electric machine 15, and the rotary electric machine 15 supplies the generated electric power to the storage batteries 11 and 12 and the electric loads 14 and 16.

The electric load 16 includes a constant voltage load in which the voltage of the supplied power is required to be constant or fluctuate within a predetermined range. Specific examples of the electric load 16 which is a constant voltage required load include various ECUs such as a navigation device, an audio device, and an engine ECU. In this case, by suppressing the voltage fluctuation of the supplied power, unnecessary resets and the like are suppressed in each of the above devices, and stable operation can be realized. Further, a lead storage battery 11 and a lithium ion storage battery 12 are connected in parallel with the electric load 16, and electric power is supplied to the electric load 16 from each of the storage batteries 11 and 12. The electric load 16 may include a traveling system actuator such as an electric steering device or a braking device.

Next, the battery unit U will be described. As an electric path in the battery unit U, an electric path L1 connecting the external terminals P1 and P2 and an electric path L2 connecting the connection point N1 on the electric path L1 and the lithium ion storage battery 12 are provided. Of these, the electric path L1 is provided with the first switch circuit SW1, and the electric path L2 is provided with the second switch circuit SW2. The electric paths L1 and L2 are large current paths assuming that an input / output current is passed through the rotary electric machine 15, and the mutual storage batteries 11 and 12 and the rotary electric machine 15 pass through the electric paths L1 and L2. Is energized. The electric path L1 corresponds to the "energization path".

Further, in the battery unit U of the present embodiment, in addition to the electric paths L1 and L2, a connection point N2 (a point between the external terminal P1 and the first switch circuit SW1) on the electric path L1 and an external terminal P3 are used. It has an electric path L3 for connecting the above. The electric path L3 forms a path that enables power to be supplied from the lead-acid battery 11 to the electric load 16. A third switch circuit SW3 is provided in the electric path L3 (specifically, between the connection point N2-connection point N4).

Further, in the battery unit U, the connection point N3 of the electric path L2 (the point between the second switch circuit SW2 and the lithium ion storage battery 12) and the connection point N4 on the electric path L3 (the third switch circuit SW3 and the external terminal P3). An electrical path L4 is provided to connect the point between) and. The electric path L4 forms a path that enables power to be supplied from the lithium ion storage battery 12 to the electric load 16. A fourth switch circuit SW4 is provided in the electric path L4 (specifically, between the connection points N3- and the connection points N4).

Each of the switch circuits SW3 and SW4 includes a set of two semiconductor switching elements. The semiconductor switching element is a MOSFET, and the parasitic diodes of the two sets of MOSFETs are connected in series so as to be opposite to each other. As the semiconductor switching element used in each of the switch circuits SW3 and SW4, it is also possible to use an IGBT, a bipolar transistor, or the like instead of the MOSFET. When an IGBT or a bipolar transistor is used, a diode instead of the parasitic diode may be connected in parallel.

The battery unit U includes a control device 21 that controls each switch circuit SW1 to SW4. The control device 21 is composed of a microcomputer including a CPU, a ROM, a RAM, an input / output interface, and the like. The control device 21 controls the switch circuits SW1 to SW4 and the like based on the storage state and the like of the storage batteries 11 and 12. For example, the control device 21 selectively uses the lead storage battery 11 and the lithium ion storage battery 12 to charge and discharge. Further, the control device 21 is connected to an ECU 22 which is a higher-level control device. The control device 21 is connected to the ECU 22 or the like by a communication network such as CAN so that it can communicate with each other, and various data can be shared with each other. Further, the battery unit U is provided with a voltage detector 23 for detecting the voltage of the external terminal P1 and a voltage detector 24 for detecting the voltage of the external terminal P2.

Next, the configuration of the first switch circuit SW1 will be described. FIG. 2 is a schematic configuration diagram of the first switch circuit SW1 in the battery unit U. Although the first switch circuit SW1 will be described for convenience, even in the case of the second switch circuit SW2, the connected storage battery is not the lead storage battery 11 but the lithium ion storage battery 12, and the second switch circuit SW2 is provided. The configuration is the same except that the electric path L1 becomes the electric path L2.

The electric path L1 has a first path L11 and a second path L12 provided in parallel between the branch point N11 and the branch point N12. Two switching elements 30 are provided in each of the paths L11 and L12. Each switching element 30 is a well-known n-type MOSFET for high power, and is a normally open type semiconductor switching element. Each switching element 30 is provided with a parasitic diode 31 due to its PN junction. The parasitic diode 31 corresponds to a "diode connected in parallel to a switching element".

A MOS driver 32 that turns on and off the switching element 30 is connected to each switching element 30. The MOS driver 32 applies a voltage for driving the switching element 30. When the switching element 30 is on, the on-resistance of the switching element 30 is extremely small, and the path can be energized when the path resistance is small. Then, the MOS driver 32 controls the drive of the switching element 30 based on the open / close command signal of the control device 21. Specifically, when the control device 21 issues a command to turn on the switching element 30 (flow a current in a closed state), a predetermined voltage is applied to the switching element 30. When the control device 21 issues a command to turn off the switching element 30 (do not allow current to flow in the open state), the voltage applied to the switching element 30 is set to 0.

In each of the paths L11 and L12, a pair of switching elements 30 are connected in series so that the parasitic diodes 31 are opposite to each other. More specifically, the switching elements 30 are connected in series in a state where the anodes of the parasitic diodes 31 face each other (back-to-back state). Of these switching elements 30, two first switching elements 30A and 30B provided in the first path L11 form the first circuit unit C1, and two second switching elements provided in the second path L12. The elements 30C and 30D form the second circuit unit C2. That is, the first path L11 is provided with a first circuit unit C1 in which two first switching elements 30A and 30B are connected in series so that the parasitic diodes 31 are opposite to each other. Further, the second path L12 is provided with a second circuit unit C2 in which two second switching elements 30C and 30D are connected in series so that the parasitic diodes 31 are oriented in opposite directions. The first circuit unit C1 and the second circuit unit C2 are in parallel with each other.

At least one of one end side and the other end side of the first switch circuit SW1 is a power supply side terminal connected to the lead storage battery 11. In each of the circuit units C1 and C2, the lead storage battery 11 is connected to the branch point N11 side, and the rotary electric machine 15 is connected to the branch point N12 side. Among the switching elements 30, the switching elements 30A and 30C on the power supply side terminal side, that is, the switching elements 30A and 30C on the branch point N11 side are power supply side elements.

A first current sensor 40A for measuring the current flowing through the first circuit unit C1 is provided between the first switching elements 30A and 30B connected in series by the first path L11. Further, a second current sensor 40B for measuring the current flowing through the second circuit unit C2 is provided between the second switching elements 30C and 30D connected in series by the second path L12. Each of the current sensors 40A and 40B has a shunt resistor 41 and an amplifier 42 connected to both ends of the shunt resistor 41. Then, in each of the paths L11 and L12, each switching element 30 and the shunt resistor 41 are connected in series. Further, the amplifier 42 detects the voltage between the terminals at both ends of the shunt resistor 41 and outputs the voltage to the control device 21.

Further, a first voltage sensor 45A that detects a voltage at a predetermined position of the first path L11 is connected to the first path L11. More specifically, the first voltage sensor 45A detects the intermediate voltage V1 between the first switching elements 30A and 30B. Similarly, the second voltage sensor 45B is also provided in the second path L12 to detect the intermediate voltage V2 between the second switching elements 30C and 30D. By detecting the voltage at the intermediate position of each switching element 30, if each switching element 30 is not turned on, the detected voltage is 0. The voltage detected by the voltage sensors 45A and 45B is output to the control device 21.

In the configuration as in this embodiment, for example, based on the amount of electricity stored in the lithium ion storage battery 12, the first switch circuit SW1 is turned off and the second switch circuit SW2 is turned on to enable charging and discharging of the lithium ion storage battery 12. , The first switch circuit SW1 is turned on and the second switch circuit SW2 is turned off to switch to a state in which the lead-acid battery 11 can be charged and discharged. Further, when the switch circuits S1 and SW2 are switched on and off, the presence or absence of an abnormality in the switch circuits SW1 and SW2 is determined. However, in the ON state of the first switch circuit SW1, a current flows through the first switch circuit SW1 even if an off abnormality occurs in the switching element 30 on either the first circuit section C1 side or the second circuit section C2 side, for example. Sometimes. Further, in the off state of the first switch circuit SW1, a current flows through the first switch circuit SW1 even if an ON abnormality occurs in the switching element 30 on either the first circuit section C1 side or the second circuit section C2 side, for example. Sometimes not. Therefore, when determining an off abnormality or an on abnormality of each switching element 30 based on the current flowing through the first switch circuit SW1, there is a concern that the abnormality determination becomes difficult.

Therefore, when the on / off of the first switch circuit SW1 is switched, instead of switching all the switching elements 30 from on to off or from off to on at the same time, the on / off of each switching element 30 is switched according to the switching order. Then, the abnormality of each switching element 30 is determined by detecting the change in the current when the switching elements 30 are switched on and off according to the switching order.

Further, when determining an abnormality of each switching element 30 based on the current change accompanying the on / off of each switching element 30, if an abnormality occurs in each of the current sensors 40A and 40B, the current change cannot be properly grasped. .. In the case of an abnormality of the current sensors 40A and 40B, if it is determined that the switching element 30 is abnormal and the fail-safe process is performed, there is a concern that the fail-safe process will be excessive. Therefore, it is desirable to be able to discriminate between the abnormality of each switching element 30 and the abnormality of each of the current sensors 40A and 40B.

Hereinafter, control when switching the on / off of each switch circuit SW1 and SW2, that is, when switching the switch circuit to be turned on will be specifically described. When switching the switch circuits SW1 and SW2, an overlapping period is provided in which both the first switch circuit SW1 and the second switch circuit SW2 are temporarily turned on. Here, the abnormality determination of each switching element 30 in the first switch circuit SW1 will be described.

When determining an abnormality in the first switch circuit SW1, the first condition is whether the switching of the first switch circuit SW1 is from the on state to the off state or from the off state to the on state, and the current at the time of switching. Is the second condition, and the switching order of each switching element 30 is set based on each of these conditions.

On / off switching of the first switch circuit SW1
(1) When the first switch circuit SW1 is switched from on to off, and when
(2) When the first switch circuit SW1 is switched from off to on, and when
It can be divided into, and the switching order is set separately for each of them (1) and (2). Then, during the switching period in which the switching elements 30 are switched according to the switching order, the abnormality determination of each switching element 30 or the like is performed.

FIG. 3 is an explanatory diagram for explaining the switching order of each switching element 30 in the cases (1) and (2) above. In FIG. 3, (a) shows the direction of the current in the on state in the first switch circuit SW1, and (b) shows the switching order of each switching element 30 in the case of the above (1), the current associated with the switching, and the current. The change in voltage is shown, and (c) shows the switching order of each switching element 30 in the case of (2) above, and the change in current and voltage accompanying the switching.

In FIG. 3A, in the first switch circuit SW1, the direction of the current in the ON state (second condition) is the direction in which the current flows from the lead-acid battery 11 side to the rotary electric machine 15 side. The direction of the current shown in FIG. 3A is the direction of the current in the on state before switching to the off state in the case of the above (1), and the direction of the current in the on state before switching to the off state in the case of the above (1), and switching from the off state in the case of the above (2). The direction of the current in the later on state.

Here, in the first circuit unit C1 and the second circuit unit C2, one of the switching elements 30 connected in series with respect to the direction of the current depends on the direction of the parasitic diode 31 and the direction of the current. It is either a "reverse element" that is in the reverse direction (reverse direction of energization) and a "forward element" that is in the forward direction (forward direction of energization) with respect to the direction of the current. In the case of FIG. 3A, since the current flows from the lead storage battery 11 side to the rotary electric machine 15 side, the first switching element 30A of the first circuit unit C1 and the second switching element 30C of the second circuit unit C2 are connected. It is a reverse element, and the first switching element 30B of the first circuit unit C1 and the second switching element 30D of the second circuit unit C2 are forward elements. For convenience of explanation, in the description assuming the state of FIG. 3A, the first switching element 30A is referred to as the “reverse direction element 30A”, the first switching element 30B is referred to as the “forward direction element 30B”, and the second switching element 30C is referred to as the second switching element 30C. The "reverse direction element 30C" and the second switching element 30D are also referred to as "forward direction element 30D".

The reverse direction elements 30A and 30C are in a conductive state when they are on, and are cut off when they are off. Further, the forward elements 30B and 30D are in a conductive state in both the on state and the off state. However, when the forward elements 30B and 30D are conducting in the off state, the conduction is conducted through the parasitic diode 31, so that the path resistance is larger than in the on state. ..

(1) On-to-off switching When switching the first switch circuit SW1 from on to off, as shown in FIG. 3 (b), the forward element 30B → the forward element 30D → the reverse element 30A → the reverse direction. The switching order is set in the order of the elements 30C, and each switching element 30 is switched from on to off at different timings.

Each timing will be described in detail. At the timing t1 when the forward element 30B is switched off, the conductive state of the forward element 30B is continued by the forward parasitic diode 31, but the path resistance increases. Therefore, the current I1 flowing through the first circuit unit C1 is reduced. Further, the current I2 flowing through the second circuit unit C2 increases according to the difference in the path resistance between the first circuit unit C1 and the second circuit unit C2.

At the timing t2 when the forward element 30D is switched off, the conductive state of the forward element 30D is continued by the forward parasitic diode 31, but the path resistance increases. In this case, since the path resistances of the circuit units C1 and C2 return to the same state, the current I1 increases and the current I2 decreases, and the currents I1 and I2 flowing through the circuit units C1 and C2 become equal.

At the timing t3 when the reverse direction element 30A is switched off, the energization of the first circuit unit C1 is cut off as the reverse direction element 30D is cut off. Therefore, the current I1 becomes zero. Further, since the energization of the first switch circuit SW1 is switched from the parallel energization of the first circuit section C1 and the second circuit section C2 to the energization of only the second circuit section C2, the current I2 increases. Further, the intermediate voltage V1 of the first circuit unit C1 becomes zero as the energization of the first circuit unit C1 is cut off.

At the timing t4 when the reverse element 30C is switched off, the energization of the second circuit unit C2 is cut off as the conduction of the reverse element 30C is cut off. Therefore, the current I2 also becomes zero. Further, the intermediate voltage V2 of the second circuit unit C2 becomes zero as the energization of the second circuit unit C2 is cut off.

Next, the abnormality determination of each part when the first switch circuit SW1 is switched from on to off as described above will be described with reference to FIGS. 4 and 5.

In the first circuit section C1,
On-failure of the reverse element 30A shown in FIG. 4 (a1) On-failure of the forward element 30B shown in FIG. 4 (a2) Failure of the first current sensor 40A shown in FIG. 4 (a3). 1 It is possible to determine an abnormality about the failure of the voltage sensor 45A. In FIG. 4, the switching order of the switching elements 30A to 30D is the same as that in FIG. 3B. Further, in FIG. 4, the current or the like in the normal state shown in FIG. 3 (b) is shown as “(a0) normal” for comparison with the abnormal time.

When the reverse element 30A is on-failed, as shown in FIG. 4A1, even if the reverse element 30A is instructed to switch off, the current I1 and the intermediate voltage V1 change before and after that. Does not occur (timing t3 in FIG. 4). This makes it possible to determine the on-failure of the reverse element 30A.

When the forward element 30B is on-failed, as shown in FIG. 4A2, even if the forward element 30B is instructed to switch off, the current I1 does not change before and after that (the current I1 does not change). Timing t1) in FIG. Further, since the path resistance of the first circuit unit C1 does not change, the current I2 does not change (timing t1 in FIG. 4).

Further, when the first current sensor 40A has a failure, as shown in FIG. 4A3, even if the reverse direction element 30A and the forward direction element 30B are turned off, the current I1 does not change ( Timing t1, t3) in FIG. On the other hand, the intermediate voltage V1 changes when the reverse element 30A is turned off (timing t3 in FIG. 4). If the current I1 does not change and the intermediate voltage V1 changes when the reverse element 30A is turned off, it can be determined that the first current sensor 40A has failed.

When the first voltage sensor 45A has a failure, as shown in FIG. 4A4, when the reverse element 30A is turned off, the current I1 changes while the intermediate voltage V1 changes. No (timing t3 in FIG. 4). Thereby, the failure of the first voltage sensor 45A can be determined.

Further, in the second circuit unit C2,
On-failure of the reverse element 30C shown in FIG. 5 (b1) On-failure of the forward element 30D shown in FIG. 5 (b2) Failure of the second current sensor 40B shown in FIG. 5 (b3). 2 It is possible to determine an abnormality about the failure of the voltage sensor 45B. In FIG. 5, the switching order of the switching elements 30A to 30D is the same as in FIG. 3B. Further, in FIG. 5, the current or the like in the normal state shown in FIG. 3 (b) is shown as “(b0) normal” for comparison with the abnormal time.

When the reverse element 30C is on-failed, as shown in FIG. 5 (b1), even if the reverse element 30C is instructed to switch off, the current I2 and the intermediate voltage V2 change before and after that. Does not occur (timing t4 in FIG. 5). This makes it possible to determine the on-failure of the reverse element 30C.

When the forward element 30D is on-failed, as shown in FIG. 5 (b2), the current I2 does not change before and after the command to switch off the forward element 30D (as shown in FIG. 5 (b2)). Timing t2 in FIG. 5). Further, since the path resistance of the second circuit unit C2 does not change, the current I1 does not change (timing t2 in FIG. 5).

Further, when the second current sensor 40B has a failure, the current I2 does not change even if the reverse element 30C and the forward element 30D are turned off, as shown in FIG. 5 (b3). Timing t2, t4) in FIG. On the other hand, when the reverse element 30C is turned off, the intermediate voltage V2 changes (timing t4 in FIG. 5). If the current I2 does not change and the intermediate voltage V2 changes when the reverse element 30C is turned off, it can be determined that the second current sensor 40B has failed.

When the second voltage sensor 45B has a failure, as shown in FIG. 5 (b4), when the reverse element 30C is turned off, the current I2 changes while the intermediate voltage V2 changes. No (timing t4 in FIG. 5). Thereby, the failure of the second voltage sensor 45B can be determined.

When switching the first switch circuit SW1 from on to off, the reverse elements 30A and 30C and the forward elements 30B and 30D are the forward elements 30B and 30D first and the reverse elements 30A and 30C later. In order, each of these switching elements 30 is switched from on to off. That is, the off switching of the forward element 30B among the two first switching elements 30A and 30B in the first circuit unit C1 to be an abnormality determination is switched so as to be switched with the reverse element 30A turned on. The order is set. Similarly, of the two second switching elements 30C and 30D in the second circuit unit C2 to be determined for abnormality, the off switching of the forward element 30D can be switched while the reverse element 30C is on. The switching order is set. As a result, by switching the forward elements 30B and 30D while the circuit units C1 and C2 are in a conductive state, the currents I1 and I2 change as the forward elements 30B and 30D are turned on and off in the normal state, while the current I1 in the abnormal state. Since I2 does not change, it is possible to determine the abnormality of the forward elements 30B and 30D.

Further, the forward elements 30B and 30D are switched from on to off while the reverse element 30C is on. That is, for the forward element 30B, the switching order is set so that the second path L12 can be switched from on to off while the second path L12 is energized. Similarly, for the forward element 30D, the switching order is set so that it can be switched from on to off while the first path L11 is in the energized state. As a result, the current diversion ratio between the first path L11 and the second path L12 changes as the forward elements 30B and 30D are turned on and off, so that the current change becomes remarkable.

Further, when the reverse direction element 30A is turned off and only the second path L12 is energized, the forward direction element 30D is turned off at that time. That is, the switching order is set so that the forward element 30D is turned off in a state where only one of the first path L11 and the second path L12 is energized. As a result, when only one path is energized, the path resistance of that path is high. Therefore, it is possible to suppress the flow of a large current.

(2) In the case of switching from off to on When switching from off to on in the first switch circuit SW1, as shown in FIG. 3 (c), the reverse element 30A → the reverse element 30C → the forward element 30B → the forward direction. The switching order is set in the order of the elements 30D, and each switching element 30 is switched from off to on at different timings.

Each timing will be described in detail. At the timing t11 when the reverse element 30A is switched on, the first circuit unit C1 is energized and the current I1 flows. Further, an intermediate voltage V1 is generated.

At the timing t12 when the reverse element 30C is switched on, the second circuit unit C2 is energized and the current I2 flows. At this time, the path resistances of the circuit units C1 and C2 become equal, and I1 = I2. Further, an intermediate voltage V2 is generated.

At the timing t13 when the forward element 30B is switched on, the path resistance of the forward element 30B decreases, so that the current I1 increases. Further, the current I2 decreases according to the difference in the path resistance of each circuit unit C1 and C2.

At the timing t14 when the forward element 30D is switched on, the path resistance of the forward element 30D decreases and the path resistances of the circuit units C1 and C2 return to the same state, so that the current I1 decreases and the current I2 increases. Then, the currents I1 and I2 flowing through the circuit units C1 and C2 are equal.

Next, the abnormality determination of each part when the first switch circuit SW1 is switched from off to on as described above will be described with reference to FIGS. 6 and 7.

In the first circuit section C1,
Off failure of the reverse element 30A shown in FIG. 6 (a1) Off failure of the forward element 30B shown in FIG. 6 (a2) Failure of the first current sensor 40A shown in FIG. 6 (a3). 1 It is possible to determine an abnormality by targeting a failure of the voltage sensor 45A. In FIG. 6, the switching order of the switching elements 30A to 30D is the same as in FIG. 3C. Further, in FIG. 6, the current or the like in the normal state shown in FIG. 3C is shown as “(a0) normal” for comparison with the abnormal time.

When the reverse element 30A has an off failure, as shown in FIG. 6A1, even if the reverse element 30A is instructed to switch on, the current I1 and the intermediate voltage V1 change before and after that. Does not occur (timing t11 in FIG. 6). This makes it possible to determine the off failure of the reverse element 30A. When the reverse element 30A is off, the intermediate voltage V1 changes when the forward element 30B is turned on (timing t13 in FIG. 6).

When the forward element 30B has an off failure, as shown in FIG. 6A2, even if the forward element 30B is instructed to switch on, the current I1 does not change before and after that (). Timing t13 in FIG. 6). Further, since the path resistance of the first circuit unit C1 does not change, the current I2 does not change (timing t11 in FIG. 6).

Further, when the first current sensor 40A has a failure, as shown in FIG. 6A3, the current I1 does not change even if the reverse element 30A and the forward element 30B are turned on (as shown in FIG. 6A3). The timings t11 and t13 in FIG. 6). On the other hand, the intermediate voltage V1 changes when the reverse element 30A is turned on (timing t11 in FIG. 6). If the current I1 does not change and the intermediate voltage V1 changes when the reverse element 30A is turned on, it can be determined that the first current sensor 40A has failed.

When the first voltage sensor 45A has a failure, as shown in FIG. 6A4, when the reverse element 30A is turned on, the current I1 changes while the intermediate voltage V1 changes. No (timing t11 in FIG. 6). Thereby, the failure of the first voltage sensor 45A can be determined.

Further, in the second circuit unit C2,
On-failure of the reverse element 30C shown in FIG. 7 (b1) On-failure of the forward element 30D shown in FIG. 7 (b2) Failure of the second current sensor 40B shown in FIG. 7 (b3). 2 It is possible to determine an abnormality by targeting the failure of the voltage sensor 45B. In FIG. 7, the switching order of the switching elements 30A to 30D is the same as in FIG. 3C. Further, in FIG. 7, the current or the like in the normal state shown in FIG. 3C is shown as “(b0) normal” for comparison with the abnormal time.

When the reverse element 30C has an off failure, as shown in FIG. 7 (b1), even if the reverse element 30C is instructed to switch on, the current I2 and the intermediate voltage V2 change before and after that. Does not occur (timing t12 in FIG. 7). This makes it possible to determine the off failure of the reverse element 30C.

When the forward element 30D has an off failure, as shown in FIG. 7 (b2), even if the forward element 30D is instructed to switch on, the current I2 does not change before and after that (the current I2 does not change). Timing t14 in FIG. 7). Further, since the path resistance of the second circuit unit C2 does not change, the current I1 does not change (timing t14 in FIG. 7).

Further, when the second current sensor 40B has a failure, as shown in FIG. 7 (b3), the current I2 does not change even if the reverse element 30C and the forward element 30D are turned on (as shown in FIG. 7 (b3)). The timings t12 and t14 in FIG. 7). On the other hand, the intermediate voltage V2 changes when the reverse element 30C is turned on (timing t12 in FIG. 7). If the current I2 does not change and the intermediate voltage V2 changes when the reverse element 30C is turned on, it can be determined that the second current sensor 40B has failed.

When the second voltage sensor 45B has a failure, as shown in FIG. 7 (b4), when the reverse element 30C is turned on, the current I2 changes while the intermediate voltage V2 changes. No (timing t12 in FIG. 7). Thereby, the failure of the second voltage sensor 45B can be determined.

When switching the first switch circuit SW1 from off to on, the reverse elements 30A and 30C and the forward elements 30B and 30D are the reverse elements 30A and 30C first and the forward elements 30B and 30D later. In order, each of these switching elements 30 is switched from off to on. That is, of the two first switching elements 30A and 30B in the first circuit unit C1 to be an abnormality determination target, the on switching of the forward element 30B is switched so as to be switched while the reverse element 30A is on. The order is set. Similarly, of the two second switching elements 30C and 30D in the second circuit unit C2 to be an abnormality determination target, the on switching of the forward element 30D can be switched while the reverse element 30C is on. The switching order is set. As a result, by switching the forward elements 30B and 30D while the circuit units C1 and C2 are in a conductive state, the currents I1 and I2 change as the forward elements 30B and 30D are turned on and off in the normal state, while the current I1 in the abnormal state. Since I2 does not change, it is possible to determine the abnormality of the forward elements 30B and 30D.

Further, the forward element 30B is switched from off to on while the reverse element 30C is on. That is, for the forward element 30B, the switching order is set so that the second path L12 can be switched from off to on while the second path L12 is energized. Similarly, for the forward element 30D, the switching order is set so that the first path L11 can be switched from off to on while the first path L11 is energized. As a result, the current diversion ratio between the first path L11 and the second path L12 changes as the forward elements 30B and 30D are turned on and off, so that the current change becomes remarkable.

Further, when the reverse direction element 30A is turned on and only the first path L11 is energized, the forward direction element 30B is turned off at that time. That is, the switching order is set so that the forward element 30B is turned off in a state where only one of the first path L11 and the second path L12 is energized. As a result, when only one path is energized, the path resistance of that path is high. Therefore, it is possible to suppress the flow of a large current.

Further, when switching from the off state to the on state of the first switch circuit SW1, the direction of the current immediately after the on switching may be unknown. In the overlapping period, both the first switch circuit SW1 and the second switch circuit SW2 are turned on, and both storage batteries 11 and 12 are electrically connected to each other. Therefore, depending on the voltage difference between the two storage batteries 11 and 12. It is possible that the current flows in an unintended direction.

Therefore, in the present embodiment, any one of the four switching elements 30 of the first switch circuit SW1 (for example, one of the two switching elements 30A and 30B in the first circuit unit C1) is switched on, and the switch is turned on. The direction of the current in the first switch circuit SW1 is determined based on the change in the current flowing through the first switch circuit SW1 due to the on switching.

For example, in FIG. 2, the first switching element 30A, which is the power supply side element in the first circuit unit C1, is turned on. When there is a change in the current flowing through the first circuit unit C1 due to the on-switching of the first switching element 30A, that is, when a current flows through the first circuit unit C1, the first switching element 30A is on the upstream side of energization. It is determined that the current flows in the direction. That is, the first switching element 30A, which is the power supply side element, can be regarded as the reverse direction element. In this case, the switching order of each switching element 30 is set based on the switching from the off state to the on state of the first switch circuit SW1 and the current flowing from the lead storage battery 11 to the rotary electric machine 15. However, since the switching order and the abnormality determination are the same as those in FIGS. 3 (c), 6 and 7, the description thereof will be omitted.

On the other hand, when there is no change in the current flowing through the first circuit unit C1 due to the on-switching of the first switching element 30A, that is, when the current does not flow through the first circuit unit C1, the first switching element It is determined that either the current is flowing in the direction in which 30A is on the downstream side of the energization, or the first switching element 30A has a failure. Whether it is any of these can be determined by the intermediate voltage V1 acquired by the first voltage sensor 45A. When the intermediate voltage V1 changes, that is, when the intermediate voltage V1 becomes a value corresponding to the power supply voltage of the lead storage battery 11, a current flows in the direction in which the first switching element 30A is on the downstream side of energization (FIG. 8 (a0)). ) Refer to). When the intermediate voltage V1 does not change, that is, when the intermediate voltage V1 remains 0V, it is determined that the first switching element 30A has failed (see FIGS. 6 (a1) and 8 (a1)).

Even when the first switching element 30B is turned on, the direction of the current can be determined in the same manner. Specifically, when there is a change in the current flowing through the first circuit unit C1 due to the on-switching of the first switching element 30B, it can be determined that the current flows in the direction in which the first switching element 30B is on the upstream side of energization. .. If there is no change in the current flowing through the first circuit unit C1 as the first switching element 30B is switched on, it can be determined that the current flows in the direction in which the first switching element 30B is on the downstream side of energization. Further, since the second switch circuit SW2 is also in the ON state during the overlapping period, the voltage of the lithium ion storage battery 12 is also applied to the branch point N12. Therefore, during the overlapping period, the first switching element 30B can also be regarded as the power source side element.

8 and 9 are explanatory views when the direction of the current is unknown in the off state, the direction of the current is determined, and the switching order is set. In this figure, it is determined that the direction of the current flows from the rotary electric machine 15 side to the lead storage battery 11 side. The switching order will be described with reference to FIG. 8 (a0). Note that FIG. 8 (a0) is the same as FIG. 9 (b0). Further, in FIGS. 8 and 9, the switching order of the switching elements 30A to 30D is the same as that in FIG. 8 (a0).

In the case of FIG. 8A0, since the current flows from the rotary electric machine 15 side to the lead storage battery 11 side, the first switching element 30A of the first circuit unit C1 and the second switching element 30C of the second circuit unit C2 are connected. It is a forward element, and the first switching element 30B of the first circuit unit C1 and the second switching element 30D of the second circuit unit C2 are opposite elements. For convenience of explanation, in the description assuming the state of FIG. 8A0, the first switching element 30A is referred to as the “forward element 30A”, the first switching element 30B is referred to as the “reverse element 30B”, and the second switching element 30C is referred to as the second switching element 30C. The "forward element 30C" and the second switching element 30D are also referred to as "reverse element 30D".

When switching the first switch circuit SW1 from off to on, as shown in FIG. 8A0, first, in order to determine the direction of the current, the first switching element 30A on the lead storage battery 11 side, which is the power supply side element, is used. Is turned on (timing t21 in FIG. 8). As a result, when the first circuit unit C1 is not energized and the intermediate voltage V1 is changed, the switching element is directed to the downstream side of energization, that is, from the rotary electric machine 15 side to the lead storage battery 11 side. It is determined that a current flows through. Then, as a result of determining the direction of the current, the first switching element 30A turned on becomes a forward-direction element, so that the first switching element 30A is turned off once.

Then, based on the determined current direction, the switching order is set in the order of reverse element 30D → reverse element 30B → forward element 30C and forward element 30A, and each switching element 30 is turned off at different timings. Can be switched on. Since it is determined that the forward element 30A is normal, the forward elements 30A and 30C are turned on at the same time, but they may be turned on at different timings.

Each timing after the direction of the current is determined will be specifically described. At the timing t22 when the reverse element 30D is switched on, the second circuit unit C2 is energized and the current I2 flows. Further, an intermediate voltage V2 is generated.

At the timing t23 when the reverse element 30B is switched on, the first circuit unit C1 is energized and the current I1 flows. At this time, the path resistances of the circuit units C1 and C2 become equal, and I1 = I2. Further, an intermediate voltage V1 is generated.

At the timing t24 when the forward elements 30A and 30C are switched on, the path resistances of the forward elements 30A and 30C decrease, and the path resistances of the circuit units C1 and C2 are equal, so that the currents I1 and I2 increase. Then, the currents I1 and I2 flowing through the circuit units C1 and C2 are equal.

Next, the abnormality determination of each part when the first switch circuit SW1 is switched from off to on as described above will be described. In the first circuit unit C1, the forward element 30A shown in FIG. 8 (a1) is turned on, the reverse element 30B shown in FIG. 8 (a2) is turned on, and the first current sensor 40A shown in FIG. 8 (a3) is turned on. It is possible to determine an abnormality about the failure of the first voltage sensor 45A shown in FIG. 8A4. In FIG. 8, the switching order of the switching elements 30A to 30D is the same as that in FIG. 8 (a0). Further, the specific determination method is almost the same as that of FIG. 6, except that the determination method for the forward element 30A is different as described above, and thus the description thereof will be omitted.

Further, in the second circuit unit C2, the forward failure of the forward element 30C shown in FIG. 9 (b1), the on failure of the reverse element 30D shown in FIG. 9 (b2), and the second current shown in FIG. 9 (b3). It is possible to determine an abnormality about the failure of the sensor 40B and the failure of the second voltage sensor 45B shown in FIG. 9 (b4). In FIG. 9, the switching order of the switching elements 30A to 30D is the same as that in FIG. 8 (a0). Further, since the specific determination method is almost the same as that in FIG. 7, the description thereof will be omitted.

When switching the first switch circuit SW1 from off to on, the direction of the current may be determined first. In this case, the first switching element 30A, which is the power supply side element, is first switched on, and the direction of the current is determined based on the change in the current accompanying the on switching. If no current flows even when the first switching element 30A, which is the power supply side element, is turned on, it is determined that this element 30A is on the downstream side of energization. On the other hand, if the element 30A is turned on and a current flows, it is determined that this element is on the upstream side of energization. In this way, when switching from the off state to the on state, even if the direction of the current cannot be grasped in advance, the direction of the current can be grasped, and each switching element 30 is based on the grasped direction of the current. By defining the on / off switching order of, the current change caused by the abnormality of the switching element 30 can be properly grasped.

If the current I1 does not change and the intermediate voltage V1 does not reach the voltage value corresponding to the power supply voltage even when the first switching element 30A, which is the power supply side element, is turned on, an abnormality occurs in the element 30A itself. Judge that it is. This makes it possible to determine whether an abnormality has occurred in the element 30A itself or whether a current does not flow because it is on the downstream side of energization.

Further, the switching order is set so that the power is supplied from the reverse element 30D of the second circuit unit C2, which is a circuit unit in which the forward element 30A, which is the power supply side element for which the direction of the current is determined, is not provided. There is. As a result, it is possible to suppress the influence of the transient state in which the forward element 30A is turned off.

FIG. 10 is a flowchart for switching on / off of the first switch circuit SW1. The process according to this flowchart is periodically executed by the control device 21. Although the first switch circuit SW1 is targeted in FIG. 10, the same processing is performed for the second switch circuit SW2.

In S10, it is determined whether to switch the switch circuit to be turned on among the switch circuits SW1 and SW2 based on the charging status of the storage batteries 11 and 12 and the like. Specifically, it is determined whether the first switch circuit SW1 is changed from the on state to the off state or from the off state to the on state based on the charging status of each of the storage batteries 11 and 12. If it is determined that the first switch circuit SW1 is not in a state of switching on / off (S10: No), the process of this flowchart ends.

If it is determined in S10 that the first switch circuit SW1 is in a state of switching on / off (S10: Yes), the process proceeds to S11. In S11, the abnormality determination target is set. Specifically, it is set whether both the first circuit unit C1 and the second circuit unit C2 are the abnormality determination targets, or one of them is the abnormality determination target. The abnormality determination target is set based on the elapsed time or the like since the previous abnormality determination was performed.

In S12, it is determined whether the first switch circuit SW1 changes from the on state to the off state. If it is determined in S12 that the first switch circuit SW1 is in the off state from the on state, that is, the first switch circuit SW1 before the on / off switching is in the on state (S12: Yes), S21 is set. move on.

In S21, the direction of the current is acquired. When the first switch circuit SW1 is on, the current sensors 40A and 40B detect the current flowing through the circuit units C1 and C2. Then, the direction of the current can be specified from the detected value of the current flowing through the circuit units C1 and C2.

In S22, the switching order of each switching element 30 is set. Whether the on / off switching of the first switch circuit SW1 is switching from the on state to the off state or switching from the off state to the on state (first condition) and the direction of the current at the time of the switching (second condition). ) And the abnormality determination target (third condition), the switching order is set. Note that S22 corresponds to the "setting unit".

When the abnormality determination target is both circuit units C1 and C2 and the on / off switching of the first switch circuit SW1 is switching from the on state to the off state, the switching order shown in FIG. 3B is changed for each switching. This is the switching order when the element 30 is turned off. Further, when the abnormality determination target is both circuit units C1 and C2 and the on / off switching of the first switch circuit SW1 is the switching from the off state to the on state, the switching order shown in FIG. 3C is changed. This is the switching order when each switching element 30 is turned on.

In the following S23, on / off switching of each switching element 30 is performed according to the switching order set in S22. Then, in S24, the currents I1 and I2 flowing through the circuit units C1 and C2 and the intermediate voltages V1 and V2 when the switching elements 30 are switched on and off are acquired. Specifically, the values detected by the current sensors 40A and 40B and the voltage sensors 45A and 45B when the switching elements 30 are switched on and off are acquired. Then, in S40, the abnormality determination of each circuit unit C1 and C2 to be the abnormality determination target is performed. The abnormality determination will be described later. In addition, S24 corresponds to "current acquisition unit", "intermediate voltage acquisition unit" and "voltage acquisition unit", and S40 corresponds to "abnormality determination unit".

If it is determined in S12 that the first switch circuit SW1 is not in the off state from the on state, that is, the first switch circuit SW1 before switching on / off is in the off state (S12: No), the process proceeds to S31. ..

In S31, it is determined whether or not it is necessary to determine the direction of the current. In the off state of the first switch circuit SW1, the current sensors 40A and 40B do not detect the current, and the direction of the current cannot be determined from the detected values of the current sensors 40A and 40B. Therefore, it is determined whether it is necessary to determine the direction of the current, specifically, whether the direction of the current can be estimated from the information outside the first switch circuit SW1, for example, the voltage of the external terminals P1 and P2. If the direction of the current can be estimated from the voltages of the external terminals P1 and P2 (detected values of the voltage detectors 23 and 24) and it is not necessary to determine the direction of the current (S31: No), the process proceeds to S21. In consideration of the possibility that the current flows in an unintended direction, the process may always proceed to S32.

In S21, the direction of the current is acquired. The direction of the current is estimated based on the voltages of the external terminals P1 and P2, and the processing after S22 is performed.

The abnormality determination process of S40 will be described with reference to FIG. FIG. 11 is a flowchart for carrying out the abnormality determination process.

In S41, it is determined whether or not there is a current change when the on / off of the reverse direction element to be determined for abnormality is switched. In S41, when there is no change in current (S41: No), in S42, when the on / off of the reverse direction element is switched, it is determined whether or not there is a change in the voltage of the path provided with the switch circuit to be determined for abnormality.

If there is no change in the voltage in S42 (S42: No), in S43, it is determined that the element in the reverse direction is abnormal, and a fail-safe process is performed. Specifically, as a fail-safe process, switching between the first switch circuit SW1 and the second switch circuit SW2 is stopped. That is, when the first switch circuit SW1 is switched from the on state to the off state, the first switch circuit SW1 is turned on, that is, all the switching elements 30 of the first switch circuit SW1 are turned on. At the same time, the second switch circuit SW2 is turned off, that is, all the switching elements of the second switch circuit SW2 are turned off. When switching the first switch circuit SW1 from the off state to the on state, the first switch circuit SW1 is turned off and the second switch circuit SW2 is turned on. In addition, the abnormality is notified to the ECU 22 and the like.

Further, in S42, when there is a change in voltage (S42: Yes), in S44, it is determined that the current sensor is abnormal, and a fail-safe process is performed. Specifically, as a fail-safe process, in the case of an abnormality in one current sensor, the value of the other current sensor is used, and the abnormality is notified to the ECU 22 or the like.

When the first switch circuit SW1 is switched from on to off, for example, as shown in FIG. 4A1, the current I1 does not change when the reverse element 30A is switched off in the first circuit unit C1. Moreover, it is determined that the reverse element 30A is abnormal based on the fact that the intermediate voltage V1 has not changed. Further, as shown in FIG. 4A3, the first current sensor 40A is based on the fact that the current I1 does not change and the intermediate voltage V1 changes when the reverse element 30A is switched off. Is determined to be abnormal. The same applies to the second circuit unit C2.

Further, when the first switch circuit SW1 is switched from off to on, for example, as shown in FIG. 6A1, a change in the current I1 occurs when the reverse element 30A is switched on in the first circuit unit C1. It is determined that the reverse element 30A is abnormal based on the fact that the intermediate voltage V1 has not changed. Further, as shown in FIG. 6A, the first current sensor 40A is based on the fact that the current I1 does not change and the intermediate voltage V1 changes when the reverse element 30A is switched on. Is determined to be abnormal. The same applies to the second circuit unit C2.

If there is a current change when the reverse element is switched on and off in S41 (S41: Yes), it is determined that there is no abnormality in the reverse element and the current sensor, and the process proceeds to S45. In S45, it is determined whether or not there is a current change when the forward element of the abnormality determination target is switched on and off. In S45, when there is no change in current (S45: No), in S46, it is determined that the forward element is abnormal, and a fail-safe process is performed. Specifically, as a fail-safe process, the ECU 22 or the like is notified of an abnormality while stopping the switching between the first switch circuit SW1 and the second switch circuit SW2.

When the first switch circuit SW1 is switched from on to off, for example, as shown in FIG. 4A2, the current I1 does not change when the forward element 30B is switched off in the first circuit unit C1. Based on this, it is determined that the forward element 30B is abnormal. The same applies to the second circuit unit C2. Further, when the first switch circuit SW1 is switched from off to on, for example, as shown in FIG. 6A2, the current I1 does not change when the forward element 30B is switched on in the first circuit unit C1. Based on this, it is determined that the forward element 30B is abnormal. The same applies to the second circuit unit C2.

If there is a current change when the forward element is switched on and off in S45 (S45: Yes), it is determined that there is no abnormality in the forward element, and the process proceeds to S47. In S47, when the on / off of the reverse direction element is switched, it is determined whether or not there is a change in the voltage of the path provided with the switch circuit to be determined for abnormality. If there is no change in the voltage in S47 (S47: No), in S48, it is determined that the voltage sensor is abnormal, and a fail-safe process is performed. Specifically, as a fail-safe process, in the case of an abnormality in one voltage sensor, the value of the other voltage sensor is used, and the abnormality is notified to the ECU 22 or the like.

When switching the first switch circuit SW1 from on to off, for example, as shown in FIG. 4A4, the first switch circuit is based on the fact that the intermediate voltage V1 does not change when the reverse element 30A is switched off. It is determined that the voltage sensor 45A is abnormal. The same applies to the second circuit unit C2. Further, when the first switch circuit SW1 is switched from off to on, as shown in FIG. 6A4, the first switch circuit SW1 is first based on the fact that the intermediate voltage V1 does not change when the reverse element 30A is switched on. It is determined that the voltage sensor 45A is abnormal. The same applies to the second circuit unit C2.

The following will be described by returning to the flowchart of FIG. When the abnormality determination process of FIG. 11 is executed in S40, the process of the flowchart ends.

If it is determined in S31 that the direction of the current needs to be determined (S31: Yes), the process proceeds to S32. In S32, the power supply side element, which is the switching element on the lead storage battery 11 side, which is the power supply, is switched on and off.

In S33, it is determined whether or not there is an abnormality in the power source side element. Specifically, it is determined whether or not there is a change in the currents I1 and I2 detected by the current sensors 40A and 40B and the intermediate voltages V1 and V2 detected by the voltage sensors 45A and 45B. When there is no change in the currents I1 and I2 and the intermediate voltages V1 and V2 (S33: Yes), it is determined that the power source side element is abnormal, and the process proceeds to S34.

For example, as shown in FIG. 6A1, the current I1 does not change and the intermediate voltage V1 does not change when the reverse element 30A, which is the power supply side element, is switched on in the first circuit unit C1. Based on the absence, it is determined that the reverse element 30A is abnormal. Further, as shown in FIG. 8A1, the current I1 does not change and the intermediate voltage V1 changes when the forward element 30A, which is the power supply side element, is switched on in the first circuit unit C1. Based on the absence, it is determined that the forward element 30A is abnormal.

In S34, a fail-safe process is performed on the assumption that the power source side element is abnormal. Specifically, as a fail-safe process, the ECU 22 or the like is notified of an abnormality while stopping the switching between the first switch circuit SW1 and the second switch circuit SW2.

When there is a change in the currents I1 and I2 and the intermediate voltages V1 and V2 (S33: No), it is determined that there is no abnormality in the power source side element, and the process proceeds to S35. In S35, the direction of the current is determined based on the change in the current accompanying the switching on / off of the power source side element. Specifically, when the current changes with the on / off of the power supply side element, it is determined that the current flows in the direction in which the turned on power supply element is on the upstream side of energization. On the other hand, when there is no change in the current, it is determined that the current flows in the direction in which the switched element turned on is on the downstream side of the energization. In addition, S35 corresponds to a "current determination unit".

In S36, the switching order of each switching element 30 is set based on the direction of the current determined in S35. When the abnormality determination target is both circuit units C1 and C2, a current flows from the lead-acid battery 11 side to the rotary electric machine 15 side, and the on / off switching of the first switch circuit SW1 is from the off state to the on state. , The switching order shown in FIG. 3C is the switching order when each switching element 30 is turned on. When the abnormality determination target is both circuit units C1 and C2, a current flows from the rotary electric machine 15 side to the lead storage battery 11 side, and the on / off switching of the first switch circuit SW1 is from the off state to the on state. , The switching order shown in FIG. 8A0 is the switching order when each switching element 30 is turned on.

In S37, the on / off of each switching element 30 is switched according to the switching order set in S36. Then, in S38, the currents I1 and I2 flowing through the circuit units C1 and C2 and the intermediate voltages V1 and V2 when the switching elements 30 are switched on and off are acquired. Then, in S40, the abnormality determination process is executed and the process is terminated.

Next, the setting of the switching order and the abnormality determination process when the abnormality determination target is only the first circuit unit C1 will be described. FIG. 12 is a time chart when the first switch circuit SW1 is switched from the on state to the off state. In FIG. 12, a current flows from the lead-acid battery 11 side to the rotary electric machine 15 side, and only the first circuit unit C1 is targeted for abnormality determination.

When switching the first switch circuit SW1 from on to off, as shown in FIG. 12A0, the switching order is set in the order of forward element 30B → reverse element 30C and forward element 30D → reverse element 30A. Then, each switching element 30 is switched from on to off so that the first switching elements 30A and 30B of the first circuit unit C1 which are the targets of abnormality determination have different timings. It is desirable that the second switching elements 30C and 30D, which are not subject to abnormality determination, are turned off at the same time in order to suppress the time required for switching.

Each timing will be described in detail. At the timing t31 when the forward element 30B is switched off, the conductive state of the forward element 30B is continued by the forward parasitic diode 31, but the path resistance increases. Therefore, the current I1 flowing through the first circuit unit C1 is reduced. Further, the current I2 flowing through the second circuit unit C2 increases according to the difference in the path resistance between the first circuit unit C1 and the second circuit unit C2.

At the timing t32 when the reverse element 30C and the forward element 30D are switched off, the energization of the second circuit unit C2 is cut off as the continuity of the reverse element 30C is cut off. Therefore, the current I2 also becomes zero. Further, the intermediate voltage V2 of the second circuit unit C2 becomes zero as the energization of the second circuit unit C2 is cut off. Further, since the energization of the first switch circuit SW1 is switched from the parallel energization of the first circuit section C1 and the second circuit section C2 to the energization of only the first circuit section C1, the current I1 increases.

At the timing t3 when the reverse direction element 30A is switched off, the energization of the first circuit unit C1 is cut off as the reverse direction element 30D is cut off. Therefore, the current I1 becomes zero. Further, the intermediate voltage V1 of the first circuit unit C1 becomes zero as the energization of the first circuit unit C1 is cut off.

In the first circuit unit C1, the reverse element 30A shown in FIG. 12 (a1) is turned on, the forward element 30B shown in FIG. 12 (a2) is turned on, and the first current sensor 40A shown in FIG. 12 (a3) is turned on. It is possible to determine an abnormality about the failure of the first voltage sensor 45A shown in FIG. 12 (a4). In FIG. 12, the switching order of the switching elements 30A to 30D is the same as that in FIG. 12 (a0). Since the specific determination method is almost the same as that in FIG. 4, the description thereof will be omitted.

FIG. 13 is a time chart when the first switch circuit SW1 is switched from the off state to the on state. In FIG. 13, a current flows from the lead-acid battery 11 side to the rotary electric machine 15 side, and only the first circuit unit C1 is targeted for abnormality determination. The setting of the switching order in this case will be described.

When switching the first switch circuit SW1 from off to on, as shown in FIG. 13 (a0), the switching order is set in the order of the reverse element 30C and the forward element 30D → the reverse element 30A → the forward element 30B. Then, each switching element 30 is switched from off to on so that the first switching elements 30A and 30B of the first circuit unit C1 which are the targets of abnormality determination have different timings. It is desirable that the second switching elements 30C and 30D, which are not subject to abnormality determination, are turned on at the same time in order to suppress the time required for switching.

Each timing will be described in detail. At the timing t41 when the reverse element 30C and the forward element 30D are switched on, the second circuit unit C2 is energized and the current I2 flows. Further, an intermediate voltage V2 is generated.

At the timing t42 when the reverse element 30A is switched on, the first circuit unit C1 is energized and the current I1 flows. Further, an intermediate voltage V1 is generated. Further, when the first circuit unit C1 is energized, the current I2 is reduced.

At the timing t43 when the forward element 30B is switched on, the path resistance of the forward element 30B decreases and the path resistances of the circuit units C1 and C2 become equal, so that the current I2 decreases and the current I1 increases. Then, the currents I1 and I2 flowing through the circuit units C1 and C2 are equal.

In the first circuit unit C1, the reverse element 30A shown in FIG. 13 (a1) is turned on, the forward element 30B shown in FIG. 13 (a2) is turned on, and the first current sensor 40A shown in FIG. 13 (a3) is turned on. It is possible to determine an abnormality about the failure of the first voltage sensor 45A shown in FIG. 13 (a4). In FIG. 13, the switching order of the switching elements 30A to 30D is the same as that in FIG. 13 (a0). Since the specific determination method is almost the same as that in FIG. 6, the description thereof will be omitted.

As described above, the switching order of each switching element 30 can be set, and the abnormality determination of each switching element 30 can be performed based on the change in the current accompanying the on / off of each switching element 30. Further, by performing an abnormality determination during the overlapping period in which both the first switch circuit SW1 and the second switch circuit SW2 are in the ON state, when an abnormality is found in the switching element 30 of each switch circuit SW1 and SW2, the abnormality is turned on. As a fail-safe process, it is possible to take measures to prevent power failure, such as stopping the switching of the switch circuit that is in a state.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

In the present embodiment, when the on / off of the first switch circuit SW1 is switched, whether the switching is from the on state to the off state or from the off state to the on state (first condition). , The on / off switching order between the two first switching elements 30A and 30B and the two second switching elements 30C and 30D is set based on the direction of the current at the time of switching (second condition). In this case, by determining the on / off switching order of each switching element 30 according to each of these conditions, it is possible to appropriately grasp the current change caused by the abnormality of the switching element 30. Then, when the on / off of each switching element 30 is switched according to the switching order, each circuit is determined to have an abnormality of at least one of the first circuit unit C1 and the second circuit unit C2 based on the acquired current. The abnormality determination of parts C1 and C2 can be properly performed.

In the configuration having two switching elements 30 in which the parasitic diodes 31 are connected in opposite directions to each other, the energization state does not change depending on the switching order of the switching elements 30. Therefore, depending on the direction of the current when the first switch circuit SW1 is switched on and off, one of the switching elements 30 becomes a forward element and the other switching element 30 becomes a reverse element, and each switching element 30 is switched. As the order, an order is set so that the forward element can be turned on and off while the reverse element is on. As a result, the forward element is switched on and off while the current is flowing through the paths L11 and L12, and the path L11. The path resistance of L12 changes. Then, it is possible to determine the abnormality of the forward element depending on whether or not a current change occurs as the forward element is turned on or off.

As for the on / off of the forward element of the first circuit unit C1 which is the abnormality determination target, the reverse element of the first circuit unit C1 is turned on, so that the first path L11 is energized and the second path is energized. The switching order is set so that the switching can be performed while the L12 is energized. That is, the switching order is set so that the on / off of the forward element of the first path L11 can be switched while both the first path L11 and the second path L12 are energized. In a state where both the first path L11 and the second path L12 are energized, the first path L11 and the second path L12 are flowing at a predetermined diversion ratio. In this state, when the forward-direction element is switched on and off, the path resistance of the first path L11 is changed, so that the diversion ratio of the first path L11 and the second path L12 changes. Therefore, the current change becomes remarkable as compared with the case where the forward element is switched on and off when the second path L12 is not energized, and the current changes as the first path L11 is energized and the forward element is turned on or off. It is possible to more reliably determine the abnormality of the forward element depending on whether or not a current change has occurred.

When switching from the off state to the on state, the direction of the current may not be known in advance. In such a case, one of the two switching elements 30A and 30B in the first circuit unit C1 is switched on, and if the current changes accordingly, the turned on switching element is on the upstream side of energization. It is determined that the current flows in the direction. On the other hand, when there is no change in the current, it is determined that the current flows in the direction in which the switched element turned on is on the downstream side of the energization. As a result, even if the direction of the current cannot be grasped in advance when switching from the off state to the on state, the direction of the current can be grasped, and based on the grasped direction of the current, each switching element 30 By determining the on / off switching order, it is possible to properly grasp the current change caused by the abnormality of the switching element 30.

When the anodes of the parasitic diodes 31 connected in parallel to each switching element 30 are connected in series so as to face each other, the intermediate voltage becomes a zero value when each switching element 30 is off. When the power supply side element is turned on, the voltage value corresponds to the power supply voltage. Further, even when the power supply side element is turned on and the intermediate voltage changes, the acquisition current does not change when the power supply side element is on the downstream side of energization.

Therefore, when the on / off of the first switch circuit SW1 is switched, the on / off of the power supply side element is switched. If neither the acquisition current nor the intermediate voltage changes even if the power supply side element is switched on and off, it is determined that the power supply side element has an abnormality not on the energized downstream side but on the power supply side element. Thereby, when the acquisition current does not change even if the power supply side element is turned on, it is possible to determine whether the power supply side element is on the downstream side of energization or whether an abnormality has occurred in the power supply side element. Therefore, the direction of the current can be correctly grasped, and by determining the on / off switching order of each switching element 30 based on the grasped direction of the current, the current change caused by the abnormality of the switching element 30 is appropriate. Can be grasped.

When only one of the first path L11 and the second path L12 is in the energized state, the switching order is set so that the forward element is turned off on the passage side in which the energized state is energized. As a result, when the reverse element is turned on in one of the first path L11 and the second path L12, the forward element is turned off and a current flows through the parasitic diode 31. Therefore, the path resistance becomes high when the current is flowing in one path, and it is possible to suppress the concentration of the current in the state where the path resistance is low in one path, so that a large current flows through each switching element 30. Can be suppressed.

When the first switch circuit SW1 is switched on and off, the intermediate voltage V1 at a predetermined position of the first path L11 provided with the first circuit unit C1 to be detected is acquired. The intermediate voltage V1 at a predetermined position of the first path L11 changes as the first switching elements 30A and 30B are switched on and off. As a result, when there is no change in the acquired current by switching the first switching elements 30A and 30B on and off and a change in the intermediate voltage V1 at a predetermined position is detected, it is determined that the first current sensor 40A is abnormal. be able to. Therefore, it is possible to prevent the fail-safe process from becoming excessive in the case of an abnormality of the first current sensor 40A.

Electric power is supplied to the rotary electric machine 15 from the lead-acid battery 11 and the lithium-ion storage battery 12, and when the power supply source is switched between the lead-acid battery 11 and the lithium-ion storage battery 12, power failure does not occur. As described above, an overlapping period is provided in which the first switch circuit SW1 and the second switch circuit SW2 are in the ON state. During this overlapping period, abnormality determination of the circuit units C1 and C2 is performed. Therefore, when an abnormality is found in each of the circuit units C1 and C2, it is possible to execute as a fail-safe process a measure that does not cause a power failure, such as stopping the switching of the first switch circuit SW1 that is turned on.

The present invention is not limited to the above embodiment, and may be implemented as follows, for example. Incidentally, the configuration of the following alternative example may be applied individually to the configuration of the above embodiment, or may be applied in any combination.

-In the above embodiment, the power supply system S is provided with two storage batteries 11 and 12, but it may be provided with only one of the storage batteries.

-In the above embodiment, the lithium ion storage battery 12 is used, but other high-density storage batteries may be used. For example, a nickel-metal hydride battery may be used. In addition, it is also possible to use the same storage battery (for example, a lead storage battery, a lithium ion storage battery, etc.).

-The switches SW3 and SW4 may also be the target of this configuration by connecting MOSFETs, which are switching elements, in parallel with each other. In that case, the "electrical device" includes the electrical load 16.

-As the switching element 30 used in each circuit unit C1 and C2, an IGBT, a bipolar transistor, or the like may be used instead of the MOSFET. When an IGBT or a bipolar transistor is used, a diode that replaces the parasitic diode 31 may be connected in parallel. Further, the switching element 30 may be a mechanical switch element instead of a semiconductor switching element.

-In the above embodiment, the shunt resistor 41 for detecting the current is provided between the switching elements 30 connected in series, but the circuit for detecting the current (shunt resistor 41) is the switching element 30. It may be provided before and after. That is, the circuit for detecting the current may be provided on each of the paths L11 and L12. Further, as the current sensor, a current detection sensor of another type may be used instead of the shunt resistor 41 and the amplifier 42.

Before setting the switching order in S22 of FIG. 10, the temperature of each circuit unit C1 or C2 may be acquired as the temperature acquisition unit. Then, when the temperature of the second circuit unit C2 is higher than that of the first circuit unit C1, the switching order may be set in S22 so that the first circuit unit C1 side is independently energized. .. For example, in the case of turning from on to off (FIG. 3B), the reverse element 30A on the first circuit unit C1 side may be switched off after the reverse element 30C is switched off. In this way, the switching order of each switching element 30 may be set so that one of the first path L11 and the second path L12 is energized based on the temperature of each circuit unit C1 and C2. .. As a result, it is possible to suppress the flow of current only in the path provided with the switch having the higher temperature. Therefore, it is possible to suppress an increase in the temperature of only the switching element of one of the circuit units.

When the first switching element 30A, which is the power supply side element, is turned on in S33 of FIG. 10 and the intermediate voltage V1 does not change, it is determined that the first switching element 30A is abnormal, and the process proceeds to S34. Based on the fact that the current I1 does not change, it may be determined that the current flows in the direction in which the first switching element 30A is on the downstream side of the current. Thereby, when the current I1 does not change and the intermediate voltage V1 does not change, it can be confirmed that the first voltage sensor 45A is not abnormal.

-In the above embodiment, the abnormality determination of the current sensors 40A and 40B was performed in S44 of FIG. 11, but the path resistances of the respective paths L11 and L12 are the same timing, that is, the first path L11 and the second path L12. Even if the abnormality determination of the current sensors 40A and 40B is performed depending on whether the detected values of the current sensors 40A and 40B are the same at the timing when the currents flowing through the currents are the same (for example, after the timing t4 in FIG. 6). Good.

11 ... lead storage battery, 12 ... lithium ion storage battery, 15 ... rotary electric machine, 30 ... switching element, 31 ... parasitic diode, L1 ... electric path, L11 ... first path, L12 ... second path, L2 ... electric path, S ... Power supply system, SW1 ... 1st switch circuit, SW2 ... 2nd switch circuit, C1 ... 1st circuit section, C2 ... 2nd circuit section.

Claims (9)

An abnormality determination device (21) that is applied to switch circuits (PM1, PM2) provided in energization paths (L1, L2) and determines an abnormality in the switch circuit.
The switch circuit has a first path (L11) and a second path (L12) provided in parallel with each other.
The first path is configured by connecting two first switching elements (30A, 30B) having diodes (31) connected in parallel in series so that the diodes are opposite to each other. One circuit unit (C1) is provided,
In the second path, two second switching elements (30C, 30D) having diodes (31) connected in parallel are connected in series so that the diodes are opposite to each other. Two circuits (C2) are provided,
When the switch circuit is switched on and off, it is based on whether the switching is from the on state to the off state or from the off state to the on state, and the direction of the current at the time of the switching. A setting unit for setting an on / off switching order between the two first switching elements and the two second switching elements, and a setting unit.
When the on / off of each switching element is switched according to the switching order, a current acquisition unit that acquires a current flowing through a circuit unit that is a target of abnormality determination among the first circuit unit and the second circuit unit, and a current acquisition unit.
Based on the acquired current acquired by the current acquisition unit, the abnormality determination unit that performs the abnormality determination of the circuit unit to be the abnormality determination target, and the abnormality determination unit.
An abnormality determination device including. When the first circuit unit is targeted for abnormality determination, the setting unit is a forward-direction element which is a switching element in which the diode is in the energization forward direction among the two first switching elements in the first circuit unit. The abnormality determination device according to claim 1, wherein the switching order is set so that the on / off can be switched in a state where the reverse direction element, which is a switching element in which the diode is energized in the reverse direction, is turned on. The setting unit sets the switching order so that the on / off of the forward element can be switched while the second path is energized when the first circuit unit is targeted for abnormality determination. The abnormality determination device according to claim 2. When switching from the off state to the on state of the switch circuit, one of the two switching elements in the first circuit unit is first turned on, and the current flowing through the switch circuit due to the on switching is performed. It is provided with a current determination unit that determines the direction of the current when the state of the switch circuit is switched based on the change of.
The current determination unit determines that when there is a change in the current flowing through the switch circuit due to the on-switching, the current flows in the direction in which the switching element that has performed the on-switching is on the upstream side of energization, and the switch circuit. The abnormality determination device according to any one of claims 1 to 3, wherein when there is no change in the current flowing through the current, it is determined that the current flows in the direction in which the switching element that has been switched on is on the downstream side of energization. .. The first circuit section and the second circuit section are configured by connecting the anodes of the diodes connected in parallel to the switching elements in series so as to face each other.
At least one of one end side and the other end side of the switch circuit is a power supply side terminal connected to the power supply unit (11, 12).
Each of the first circuit unit and the second circuit unit includes an intermediate voltage acquisition unit that acquires an intermediate voltage between the two switching elements.
When the on / off of the switch circuit is switched, the on / off of the power supply side element which is the switching element on the power supply side terminal side of each of the two switching elements in the first circuit unit or the second circuit unit is switched. The abnormality determination device according to claim 4, wherein it is determined that an abnormality has occurred in the power supply side element when neither the acquisition current by the current acquisition unit nor the intermediate voltage changes. In each of the circuit units, one of the two switching elements is a forward-direction element that is the switching element in which the diode is in the energization forward direction, and the other is the switching element in which the diode is in the energization reverse direction. It is a reverse element,
In the setting unit, when only one of the first path and the second path is energized, the switching order is such that the forward element is turned off on the path side that is energized. The abnormality determination device according to any one of claims 1 to 5. It has a temperature acquisition unit that acquires the temperature of the first circuit unit and the second circuit unit, respectively.
Claim 1 in which the setting unit sets the switching order of the switching element so that one of the first path and the second path is energized based on the temperature of each circuit unit. The abnormality determination device according to any one of claims 6. When the first circuit unit is targeted for abnormality determination, a voltage acquisition unit that acquires a voltage at a predetermined position of the first path when the on / off of each switching element is switched according to the switching order is provided. And
The current acquisition unit acquires the detection value of the current sensor provided on the first path as the acquisition current, and obtains the acquisition current.
When the switching elements are switched on and off according to the switching order, the abnormality determination unit does not change the acquired current, and if there is a change in the voltage at a predetermined position in the first path, the current. The abnormality determination device according to any one of claims 1 to 7, wherein the abnormality is determined to be an abnormality of the sensor. It has a first power source (11) and a second power source (12), which are connected in parallel to the electric device (15) by the energization path.
In the energization path, as the switch circuit, a first energization path (SW1) is provided in the first energization path (L1) connected to the first power supply, and a second energization path (SW1) connected to the second power supply is provided. It is applied to the power supply system (S) in which the second switch circuit (SW2) is provided in L2).
When switching the switch circuit to be turned on among the first switch circuit and the second switch circuit, an overlapping period is provided in which both switch circuits are temporarily turned on.
The current acquisition unit acquires the current flowing through the circuit unit to be determined for abnormality when the switching elements of the switching elements are switched on and off according to the switching order during the overlapping period.
Any of claims 1 to 8, wherein the abnormality determination unit performs abnormality determination of the circuit unit subject to the abnormality determination based on the acquisition current acquired by the current acquisition unit during the overlap period. The abnormality determination device according to item 1.

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