JP5930910B2 - Power supply - Google Patents

Description

  The present invention relates to a power supply apparatus that can efficiently generate power and can continue to supply power even when voltage conversion means becomes abnormal.

  Among the conventional vehicle power supply devices, for the power supply device that can efficiently generate power, as shown in Patent Document 1, the generator is controlled to generate power at the operating point where the power generation efficiency is maximum, A device having voltage conversion means for converting the magnitude of the output voltage of the generator into a predetermined voltage value is disclosed.

  According to this conventional device, by making the output terminal voltage of the generator variable, the maximum output power of the generator can be increased, and the power generation is performed at the output terminal voltage at which the efficiency is optimum, so the power generation efficiency is also improved. Is done. In this case, the voltage suitable for the electric load or battery and the generator output terminal voltage at which the power generation efficiency is maximized are generally different, but it is possible to connect the generator and the electric load by using the voltage conversion means. It becomes.

JP 2001-103796 A

  In the case of the above-described conventional apparatus, the electric power generated from the generator is supplied to the electric load through the voltage conversion means. In this respect, a general voltage conversion means has a complicated configuration such as a switching element and a controller for controlling the switching element. Therefore, when an abnormal operation occurs due to a failure or the like, power can be appropriately supplied. There is a risk of disappearing. For example, when a power supply is short-circuited due to conduction of an unnecessary switching element due to control abnormality or the like, the switching element may be burned out.

  As described above, when power is not supplied due to a failure of the voltage conversion means, there is a concern that it is not possible to drive a device necessary for traveling the vehicle or a device for operating the internal combustion engine. In order to prevent this, it is conceivable to provide a relay in parallel with the voltage conversion means, and to supply power via the relay when the voltage conversion means is abnormal. However, since a relay, wiring, etc. are needed, there exists a possibility of causing an increase in weight, size, and cost.

  On the other hand, as described in Patent Document 1, in the case of a configuration in which a bypass diode is provided for the switching element, power can be supplied even when the switching element is broken. Even if the switching element malfunctions, there is no short circuit. However, since the voltage conversion efficiency during normal operation decreases due to an increase in loss in the diode, it cannot be said to be a preferable configuration.

  The present invention was made to solve the above-described problems in the conventional apparatus, and can efficiently generate power and add components such as a bypass circuit when the voltage conversion means becomes abnormal. It is an object of the present invention to provide a power supply device that can continue to supply electric power.

  A power supply apparatus according to a first aspect of the present invention includes voltage conversion means connected between a DC power supply and an electric load, converts the output voltage of the DC power supply by the voltage conversion means and supplies power to the electric load. The voltage conversion means includes a first switching element connected to the positive terminal side of the DC power source, a second switching element connected to the DC power source and the negative terminal side of the electric load, An inductor having one terminal connected to the connection point of the first and second switching elements and the other terminal connected to the positive terminal side of the electric load, and alternately switching the first and second switching elements. The output voltage of the DC power supply is converted by connecting / disconnecting the first and second switching elements. When both the first and second switching elements become conductive due to abnormality, the first switch is switched. Disconnection failure detection for setting the characteristics of the first and second switching elements so that the second switching element is broken before the chucking element and detecting whether the second switching element is broken or not. And a conduction holding means for holding the first switching element so that the first switching element is always in a conductive state when the disconnection fault detection means detects a disconnection fault of the second switching element. ing.

  According to a second aspect of the present invention, there is provided a power supply device comprising: a power storage device connected in parallel to an electric load; and a voltage conversion means connected between a DC power supply and the electric load. An output voltage of a DC power supply is converted to supply electric power to the electric load, and the voltage conversion means includes a first switching element connected to a positive terminal side of the electric load, the DC power supply, and the One terminal is connected to the connection point of the second switching element connected to the negative terminal side of the electrical load and the first and second switching elements, and the other terminal is connected to the positive terminal side of the DC power supply. An inductor, and converts the output voltage of the DC power supply by alternately conducting / disconnecting the first and second switching elements, and the first and second switching elements are different from each other. And setting the characteristics of the first and second switching elements so that the second switching element breaks before the first switching element. A disconnection fault detecting means for detecting whether or not the disconnection fault has occurred, and when the disconnection fault detecting means detects a disconnection fault of the second switching element, the first switching element is always in a conductive state accordingly. And a conduction holding means for holding so that.

  According to a third aspect of the present invention, there is provided a power supply apparatus comprising voltage conversion means connected between a DC power supply and an electric load, wherein the voltage conversion means converts the output voltage of the DC power supply and supplies power to the electric load. The voltage conversion means includes first and second switching elements sequentially connected in series between a positive electrode terminal and a negative electrode terminal of the DC power supply, and a positive electrode terminal and a negative electrode terminal of the electric load. A third and a fourth switching element sequentially connected in series, and an inductor connected between a connection point of the first and second switching elements and a connection point of the third and fourth switching elements; The output voltage of the DC power supply is converted by alternately conducting / disconnecting the combination of the first and fourth switching elements and the combination of the second and third switching elements. When the conduction state of the combination of the first and fourth switching elements is longer than that in the normal operation state due to an abnormality, the fourth switching element is disconnected earlier than the first switching element. The characteristics of the first and fourth switching elements are set so as to break down, and a disconnection fault detecting means for detecting whether or not the fourth switching element has a disconnection fault, and the disconnection fault detecting means is the fourth switching element. When the disconnection failure of the element is detected, the second switching element is always disconnected according to this, and the first switching element and the third switching element are always kept in the conductive state. And holding means.

  Since the power supply device according to the first invention has the above-described configuration, when the voltage from the DC power supply is stepped down by the power conversion means and supplied to the electric load, the ground current from the DC power supply, etc. Even when a disconnection failure occurs in the switching element of the power conversion means due to the above, it is possible to continue supplying power without adding components such as a bypass circuit.

  In addition, since the power supply device according to the second invention has the above-described configuration, when the voltage from the DC power supply is boosted by the power conversion means and supplied to the electric load, the power supply device is connected in parallel to the electric load. Even when a disconnection failure occurs in the switching element of the power conversion means due to a ground current from the power storage device, it is possible to continue supplying power without adding components such as a bypass circuit.

  In addition, since the power supply device according to the third invention has the above-described configuration, when the voltage from the DC power supply is stepped up and down by the power conversion means and supplied to the electric load, the ground current from the DC power supply, etc. Even when a disconnection failure occurs in the switching element of the power conversion means due to the above, it is possible to continue supplying power without adding components such as a bypass circuit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the whole power supply device which concerns on Embodiment 1 of this invention. It is a circuit diagram of the voltage converter in the power supply device shown in FIG. It is a flowchart which shows the power supply apparatus related process of the control unit in the power supply apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process of the controller in the power supply device which concerns on Embodiment 1 of this invention. It is a circuit diagram of the voltage converter in the power supply device which concerns on Embodiment 2 of this invention. It is a block diagram which shows the whole power supply device which concerns on Embodiment 3 of this invention. It is a circuit diagram of the voltage converter in the power supply device shown in FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the entirety of a power supply device according to Embodiment 1 of the present invention, and FIG. 2 is a circuit diagram of a voltage converter in the power supply device shown in FIG.

  A generator 1 as a DC power source is belt-connected to an internal combustion engine (not shown) and is driven by the internal combustion engine to generate electric power. As another configuration, for example, a generator may be sandwiched and connected between the internal combustion engine and the transmission, and in this case, it is possible to drive with a larger power generation torque than the belt connection. .

  The configuration of the generator 1 may be the same as that of an alternator used in a general vehicle, and the generated power can be adjusted by controlling the field current flowing through the rotor. However, as will be described later, in order to increase the power generation voltage, it is possible to generate power at a higher voltage than the conventional one and to generate power at the required voltage of the in-vehicle electric load 4.

  Here, the voltage converter 2 which is a voltage converting means is a step-down voltage converter, and its input terminal in is connected to the positive terminal side of the generator 1 and its output terminal out is connected to the load feeding bus 5. The load power supply bus 5 is connected to a lead battery 3 that is a power storage device and a positive terminal side of an in-vehicle electric load 4. Since the voltage converter 2 is a non-insulated voltage converter, the negative electrode terminal sides of the generator 1, the voltage converter 2, the lead battery 3, and the electric load 4 are connected as a common ground. Therefore, the power storage device 3 is connected to the electric load 4 in parallel.

  Although not shown, the control unit 6 includes an arithmetic device (hereinafter referred to as a CPU) such as a microcomputer, a memory, and the like, and also includes control means for the generator 1 and the voltage converter 2.

  The control unit 6 is connected to a sensor, an actuator, etc. (not shown) provided in the internal combustion engine and the like, and is also connected to a generator 1, and voltage detection for detecting the input / output voltage of the voltage converter 2. Lines 7 and 8 are connected. Further, the voltage converter 2 is connected via the control signal lines 9 and 10.

  The control unit 6 detects signals from other devices, actuators, etc. and values obtained from the sensors. Further, the input / output voltage of the voltage converter 2 by the voltage detection lines 7 and 8 is also detected by a known method such as, for example, dividing the voltage and then converting it to a digital value by an A / D converter. The control unit 6 controls the generator 1, the voltage converter 2, the actuator, and the like based on the detection values obtained from these sensors, actuators, and the like.

  That is, the control unit 6 determines a target voltage for the generator 1 that can efficiently generate power based on the operating state and controls the field current so that the generated voltage detected through the voltage detection line 7 becomes the value. To do. Further, for the voltage converter 2, the target value of the output voltage of the voltage converter 2 is determined according to the state of the lead battery 3 and the electric load 4 in addition to the operating state, and the voltage is supplied via the control signal line 10. A signal is sent as an instruction value to the controller 22 described later of the converter 2.

  Furthermore, the control unit 6 also performs control when an abnormality of the voltage converter 2 is detected. That is, when an abnormal signal is sent from the voltage converter 2 via the control signal line 10 or when an abnormality of the voltage converter 2 is detected by itself, the voltage converter 2 cannot perform normal voltage conversion. Since it is in the state, the target voltage corresponding to the state of the lead battery 3 and the electric load 4 is determined. Further, as described later, when the abnormality of the voltage converter 2 is detected, the operation of the driver 21 is also controlled via the control signal line 9.

  By the way, since the lead battery 3 used for a general vehicle has an open circuit voltage of about 12V and a charge voltage of about 14V, when the power generation voltage of the generator 1 is higher than the charge voltage of the lead battery 3, it is output from the input terminal in. It is necessary to step down the voltage in the direction of the terminal out. It should be noted that the maximum voltage generated by the generator 1 is difficult to increase excessively due to restrictions on parts and safety in preventing electric shocks, and should be about 28 V in consideration of the characteristics of the generator. That's fine.

  Therefore, as the voltage converter 2, as shown in FIG. 2, a step-down chopper circuit using two first and second switching elements 11, 12 made of MOSFETs, an inductor 15, and the like is applied. A driver 21 and a controller 22 are provided for driving and controlling these switching elements 11 and 12.

  As a specific configuration of the voltage converter 2, the drain of the first switching element 11 is connected to the input terminal in on the positive terminal side of the generator 1, and the source is connected to the drain of the second switching element 12. The source of the second switching element 12 is connected to a common ground terminal GND on the negative terminal side. Further, one end of the inductor 15 is connected to a common connection point of the first and second switching elements 11 and 12, the other end of the inductor 15 is connected to the output terminal out, and the lead battery is connected via the load feeding bus 5. 3 and the positive terminal side of the electric load 4. Furthermore, in order to absorb voltage fluctuations due to switching of the first and second switching elements 11 and 12, voltage smoothing capacitors 16 and 17 are provided at the input terminal in and the output terminal out, respectively.

  The voltage conversion operation at the normal time of the voltage converter 2 may be a known method. For example, the first and second switching elements 11 and 12 are sent via the driver 21 by a signal from the controller 22 so as to obtain a target output voltage. Are alternately conducted (ON) / disconnected (OFF). In this case, when the output voltage is increased, the conduction period of the first switching element 11 is lengthened. Conversely, when the output voltage is desired to be lowered, the conduction period of the first switching element 11 is shortened. However, when this normal control is performed, the switching elements 11 and 12 are not simultaneously conducted.

  However, when both the switching elements 11 and 12 are simultaneously turned on due to an abnormality of the controller 22 or the like, the generated current of the generator 1 is grounded through these switching elements 11 and 12. An excessive current will flow through. Thereby, it is conceivable that both switching elements 11 and 12 generate heat and burn out, and when one of both switching elements 11 and 12 burns out, the ground current is cut off. In this case, if the characteristics of the switching elements 11 and 12 are the same, which switching element 11 or 12 is burned out is considered to vary depending on individual variations and usage conditions.

  For example, when one of the first switching elements 11 is burned out, the power of the generator 1 cannot be supplied to the electric load 4 or the like. On the other hand, when the other second switching element 12 is burned out, the first switching element 11 is turned on while maintaining the state in which the switching element 12 is disconnected, so that the electric power of the generator 1 is It can be continuously supplied to the load 4 or the like. However, in this case, the voltage converter 2 has only the function of a conducting wire, and the voltage conversion function is lost. For this reason, it is necessary to control the power generation voltage of the generator 1 to the required voltage of the electric load 4.

  Therefore, when a ground current flows through both the switching elements 11 and 12, the second switching element 12 is burned first to cause a disconnection failure, and when the disconnection failure is detected, the first switching element is detected. Only 11 is always in a conductive state. Thereby, the electric power of the generator 1 can be continuously supplied to the electric load 4 or the like.

  In order to cause the second switching element 12 on the other side to burn out earlier than the first switching element 11 when a ground current flows, the current withstand capability of the second switching element 12 is, for example, Different MOSFET characteristics may be set, for example, by setting it to be smaller than that of the first switching element 11. By doing so, the power of the generator 1 can be continuously supplied to the electrical load 4 and the like even after an abnormality has occurred without adding components such as a bypass circuit.

  Regarding the detection method of the disconnection failure of the second switching element 12 when a ground current flows through both the switching elements 11 and 12, the controller 22 determines the ratio of the conduction / disconnection period of the first and second switching elements 11 and 12. The disconnection is detected from the relationship with the input / output voltage ratio of the voltage converter 2. That is, if the switching elements 11 and 12 are operating normally, the relationship between the input and output voltage ratios of the voltage converter 2 is uniquely determined according to the ratio of the respective conduction / disconnection periods. If a disconnection failure occurs, it is detected. Of course, the potential difference between the source and drain of the second switching element 12 may be directly measured.

  When a disconnection failure is detected, the controller 22 sends a signal indicating an abnormal state to the control unit 6 via the control signal line 10. Thereby, it is possible to cope with the abnormality detection earlier than when the control unit 6 directly detects the abnormality of the voltage converter 2.

  As for the constant energization method for the first switching element 11 when the disconnection failure of the second switching element 12 is detected, the controller 22 sends a signal to the driver 21 that only the first switching element 11 is always energized. In response to this, the driver 21 outputs a drive signal to the first switching element 11 to make it always conductive.

  At this time, the second switching element 12 is in a disconnection failure state, but if it is temporary, there is a risk of re-conduction. Therefore, when a disconnection failure of the second switching element 12 is detected so that the second switching element 12 is prevented from conducting again and the disconnected state is maintained, the controller 22 notifies the driver 21 of the switching element. 12 continuously sends a signal for maintaining the disconnected state.

  Further, when an abnormality such as a failure occurs in the controller 22 itself, voltage control by the controller 22 cannot be performed. Therefore, it is preferable that the control unit 6 can also control the driver 21 when abnormality is detected. .

  For this purpose, for example, the driver 21 can receive not only the always-on instruction signal from the controller 22 but also the always-on instruction signal given from the control unit 6 via the control signal line 9. It should be possible to operate in response to either of the continuous energization instructions. As a result, even when an abnormality occurs in the controller 22 itself, the control unit 6 can continuously perform the operation of maintaining the normally energized state for the first switching element 11.

  Furthermore, it is more preferable to improve the reliability of the apparatus by allowing the control unit 6 to detect the abnormality of the voltage converter 2. For this purpose, for example, when the indicated value of the output voltage for the voltage converter 2 is compared with the actual output voltage detected through the voltage detection line 8, the difference between the two voltages is more than a predetermined reference value set in advance. It can be determined that an abnormality has occurred in the voltage converter 2.

  The driver 21 corresponds to the conduction holding means in the claims, the controller 22 is the disconnection failure detecting means in the claims, and the control unit 6 is the external device in the claims. Each corresponds to a disconnection failure detecting means.

Next, the operation of the power supply device according to Embodiment 1 of the present invention will be described.
FIG. 3 is a flowchart showing processing related to the power supply apparatus executed at a constant cycle (for example, 0.01 seconds) in the control unit 6 of the power supply apparatus.

  In FIG. 3, the control unit 6 first performs an abnormality detection process for the voltage converter 2 in step S101. That is, if the controller 22 is normal, an abnormal signal of the voltage converter 2 can be obtained from the controller 22 when the switching elements 11, 12, etc. fail, but if the controller 22 itself is abnormal, an abnormality is externally detected. It needs to be detected. As a detection method for that purpose, as described above, the control unit 6 compares the indicated value of the output voltage to the voltage converter 2 with the actual output voltage detected through the voltage detection line 8 to obtain a predetermined value. An abnormality is detected when the above deviates.

  Next, in step S102, it is determined whether or not the voltage converter 2 is abnormal. If it is determined that the voltage converter 2 is normal (not abnormal) as a result of performing the abnormality detection process on the voltage converter 2 in step S101, the voltage converter instruction process is performed via the control signal line 10 in step S103. Then, a signal is sent to the voltage converter 2 using the target value of the output voltage as an instruction value. Then, in step S104, as the optimum power generation voltage calculation process, a target voltage that can be generated efficiently is determined, the field current of the generator 1 is controlled, and the process of FIG.

  On the other hand, if it is determined in step S102 that the voltage converter 2 is abnormal as a result of performing the abnormality detection process on the voltage converter 2 in step S101, the control unit 6 connects the control signal line 9 in step S105. Through the driver 21 to send an energization instruction signal. In step S106, the continuity holding power generation voltage calculation process is performed, and the process of FIG. 3 ends. In this process, since the voltage conversion function in the voltage converter 2 is lost, the control unit 6 determines the target voltage according to the state of the lead battery 3 and the electric load 4 and determines the field current of the generator 1. Control.

Next, the operation of the controller 22 of the power supply device will be described.
FIG. 4 is a flowchart showing processing related to the power supply apparatus executed at a constant cycle (for example, 0.01 seconds) in the controller 22 of the power supply apparatus.

  In FIG. 4, the controller 22 first determines in step S201 from the relationship between the ratio of the conduction / disconnection period of the first and second switching elements 11 and 12 and the input / output voltage ratio of the voltage converter 2 as described above. Detects whether there is a disconnection failure. In this case, the input / output voltage of the voltage converter 2 is divided into the digital value by the A / D converter of the controller 22 after dividing the voltage obtained from the voltage detection lines 23 and 24 as in the case of the control unit 6. Detect by converting.

  Next, the controller 22 determines whether or not the second switching element 12 is broken in step S202. If the 2nd switching element 12 is normal (it is not disconnected), a voltage conversion control process will be implemented in step S203 and the process of FIG. 4 will be complete | finished. In this process, the conduction / disconnection period of both switching elements 11 and 12 is controlled so that the output voltage of the voltage converter 2 becomes an instruction value from the control unit 6. The conduction / disconnection cycle of both the switching elements 11 and 12 is determined by voltage fluctuation, component characteristics such as an inductor, loss, etc., and may be about several tens of kHz.

  On the other hand, when it is determined in step S202 that the second switching element 12 is a disconnection failure, the controller 22 sends a signal for constantly energizing to the driver 21 in step S204 as the conduction maintaining control process, and performs the process of FIG. finish. If the controller 22 itself is abnormal due to a failure or the like, this processing will not be performed. However, as described above (FIG. 3), the control unit 6 also performs the continuity holding control processing, which causes some problem. The power supply can be continued without any problems.

Embodiment 2. FIG.
FIG. 5 is a circuit diagram of a voltage converter in a power supply device according to Embodiment 2 of the present invention. Components corresponding to or corresponding to those of Embodiment 1 shown in FIG.

  The power supply device according to the second embodiment is a case where the power generation voltage of the generator 1 is lower than the charging voltage of the lead battery 3. In that case, the voltage converter 2 needs to boost the voltage in the direction from the input terminal in to the output terminal out. Therefore, as the voltage converter 2, a step-up chopper circuit using two third and fourth switching elements 13 and 14 made of, for example, a MOSFET and an inductor 15 is applied.

  That is, in the voltage converter 2, the drain of the third switching element 13 is connected to the output terminal out on the positive terminal side to which the lead battery 3 and the electric load 4 are connected via the load feeding bus 5, and the source is the fourth. The drain of the switching element 14 is connected. The source of the fourth switching element 14 is connected to the common ground terminal GND on the negative electrode terminal side. One end of the inductor 15 is connected to a common connection point of the third and fourth switching elements 13 and 14, and the other end of the inductor 15 is connected to the input terminal in on the positive terminal side. Furthermore, in order to absorb voltage fluctuations due to switching of the third and fourth switching elements 13 and 14, voltage smoothing capacitors 16 and 17 are provided at the input terminal in and the output terminal out, respectively.

  In the configuration of the second embodiment, the third and fourth switching elements 13 and 14 correspond to the first and second switching elements in the claims (Claim 2), respectively. Other configurations are the same as those of the first embodiment.

  The voltage conversion operation at the normal time of the voltage converter 2 having the configuration shown in FIG. 5 may be a known method as in the first embodiment, and the controller 22 uses the driver 21 via the driver 21 so as to obtain a target output voltage. The fourth switching elements 13 and 14 are alternately conducted (ON) / disconnected (OFF). In this case, when it is desired to increase the output voltage, the conduction period of the third switching element 13 is shortened. Conversely, when the output voltage is desired to be lowered, the conduction period of the third switching element 13 is lengthened. However, the switching elements 13 and 14 are not simultaneously conducted.

  However, when both the switching elements 13 and 14 are turned on simultaneously due to an abnormality of the controller 22 or the like, the discharge current of the lead battery 3 that is a power storage device connected to the output terminal out side is grounded through these switching elements 13 and 14. Therefore, an excessive current flows through both the switching elements 13 and 14. Thereby, it is conceivable that both switching elements 13 and 14 generate heat and burn out as in the first embodiment.

  Therefore, also in the second embodiment, as in the first embodiment, when the ground current flows through both the switching elements 13 and 14, the fourth switching element 14 is burned out before the third switching element 13. A disconnection failure is caused, and when the disconnection failure is detected, only the third switching element 13 is always in a conductive state. Thereby, the electric power of the generator 1 can be continuously supplied to the electrical load 4 and the like even after an abnormality has occurred without adding components such as a bypass circuit.

  Note that the processing operations of the driver 21 as the continuity holding means and the controller 22 and the control unit 6 as the disconnection failure detection means may be the same as those in the first embodiment, and thus detailed description thereof is omitted here. .

Embodiment 3 FIG.
6 is a block diagram showing the whole power supply apparatus according to Embodiment 3 of the present invention. FIG. 7 is a circuit diagram of a voltage converter in the power supply apparatus of FIG. 6, and the embodiment shown in FIG. 1 and FIG. Components corresponding to or corresponding to 1 are denoted by the same reference numerals.

  In the power supply device according to the third embodiment, an electric double layer capacitor 31 is provided between the generator 1 and the voltage converter 2 via a switch 32. The switch 32 in this case can be connected to the control unit 6 to control conduction / disconnection.

  Since the electric double layer capacitor 31 can receive and transfer a larger amount of electric power than a lead battery, it is possible to store more power generated by regenerative power generation at the time of deceleration, for example, by adopting such a configuration. However, as a characteristic of the electric double layer capacitor 31, the terminal voltage changes according to the amount of stored electric power. Therefore, in order to increase the amount of stored electric power that can be used, the width of change in the terminal voltage of the electric double layer capacitor 31 is increased. It is necessary to convert the voltage into a necessary voltage by using the voltage converter 2 for step-up / step-down. Since the general electric double layer capacitor 31 can be used at a maximum of about 3V per cell, it can be used up to a maximum of 30V if it is composed of 10 in series. The lower limit voltage is set to about 10 V because the current with respect to the required power becomes large when the voltage is unnecessarily low.

  Since the voltage converter 2 is provided with the electric double layer capacitor 31, it is necessary to step up and step down the voltage in the direction from the input terminal in to the output terminal out. Therefore, as shown in FIG. A step-up / down type chopper circuit using four first to fourth switching elements 11 to 14 and an inductor 15 or the like is applied.

  That is, in the voltage converter 2, the drain of the first switching element 11 is connected to the input terminal in which is the positive terminal side of the generator 1 and the electric double layer capacitor 31, and the source is connected to the drain of the second switching element 12. Is done. The source of the second switching element 12 is connected to a common ground terminal GND on the negative terminal side.

  On the other hand, the drain of the third switching element 13 is connected to the output terminal out on the positive terminal side of the lead battery 3 and the electric load 4 via the load feeding bus 5, and the source is connected to the drain of the fourth switching element 14. . The source of the fourth switching element 14 is connected to a common ground terminal GND on the negative terminal side.

  Further, both ends of the inductor 15 are connected between a common connection point of the first and second switching elements 11 and 12 and a common connection point of the third and fourth switching elements 13 and 14. Furthermore, in order to absorb voltage fluctuations due to switching of the first to fourth switching elements 11 to 14, voltage smoothing capacitors 16 and 17 are provided at the input terminal in and the output terminal out, respectively. Other configurations are the same as those of the first embodiment.

There are three voltage conversion operations when the voltage converter 2 is normal as shown below.
First, as the first operation, the voltage is stepped down in the direction from the input terminal in to the output terminal out. That is, it is used when the terminal voltage of the electric double layer capacitor 31 is higher than the required voltage of the electric load 4 or the like. In this operation, the third switching element 13 is always energized and the fourth switching element 14 is always disconnected, and only the first and second switching elements 11 and 12 are switched. In this case, the voltage converter 2 is substantially the same as the configuration shown in FIG. 2, and therefore the same operation as in the first embodiment is performed.

  Next, as a second operation, the voltage is boosted in the direction from the input terminal in to the output terminal out. That is, it is used when the terminal voltage of the electric double layer capacitor 31 is lower than the required voltage of the electric load 4 or the like. In this operation, the first switching element 11 is always energized and the second switching element 12 is always disconnected, and only the third and fourth switching elements 13 and 14 are switched. In this case, the voltage converter 2 is substantially the same as the configuration shown in FIG. 5, and therefore the same operation as in the second embodiment is performed.

  Finally, the third operation is a case where the voltage is stepped up or down in the direction from the input terminal in to the output terminal out. When the terminal voltage of the electric double layer capacitor 31 and the required voltage of the electric load 4 are approximate values, voltage conversion can be performed continuously. In this operation, the combination of the first and fourth switching elements 11 and 14 and the combination of the second and third switching elements 12 and 13 are alternately conducted / disconnected.

  Here, when both the first and fourth switching elements 11 and 14 are turned on, the generator 1 is connected to the ground terminal GND via the inductor 15, and both the second and third switching elements 12 and 13 are turned on. In this case, the lead battery 3 is connected to the ground terminal GND via the inductor 15, but since both are in a normal state for a short period, no large current flows through the inductor 15.

  However, if the conduction of the combination of the first and fourth switching elements 11 and 14 or the second and third switching elements 12 and 13 is continued for a long time due to an abnormality of the controller 22, an excessive ground current is generated. One of the switching elements 11 to 14 may generate heat and burn out.

  Therefore, as in the case of the first and second operations described above, when a ground current flows through the first and fourth switching elements 11, 14 or the second and third switching elements 12, 13, the first The second and fourth switching elements 12 and 14 are burned out before the third switching elements 11 and 13 so as to cause a disconnection failure. When the disconnection failure is detected, both the second and fourth switching elements 12 and 14 are always disconnected, and the first and third switching elements 11 and 13 are always conductive. Thereby, the electric power of the generator 1 can be continuously supplied to the electrical load 4 and the like even after an abnormality has occurred without adding components such as a bypass circuit.

  In this case, it is necessary to set the power generation voltage of the generator 1 to the required voltage of the electric load 4, but since the terminal voltage of the electric double layer capacitor 31 may be different, the switch 32 is disconnected so as not to be affected by it. The electric double layer capacitor 31 is disconnected as a state.

  The processing of the driver 21 as the continuity holding means and the processing of the controller 22 and the control unit 6 as the disconnection failure detection means may be the same as in the first and second embodiments except for the points described below.

  The difference between the driver 21 and the first embodiment is that not only the first switching element 11 but also the third switching element 13 is always in a conducting state when a disconnection failure is detected, and the second switching element 12 and the fourth switching element 14 This is a point that is always disconnected.

  That is, it is the second switching element 12 or the fourth switching element 14 that causes the disconnection failure. However, as in the first and second embodiments, if the disconnection failure state is temporary, the second switching element 12 Or there exists a possibility that the 4th switching element 14 may re-energize. Therefore, the controller 22 always disconnects the driver 21 from the controller 22 so that the second switching element 12 or the fourth switching element 14 is prevented from re-conducting and both the switching elements 12 and 14 are maintained in the disconnected state. The signal for holding is continuously sent. In this way, the switching element in which the disconnection failure is detected is always kept in the disconnected state, so that it is not necessary to switch the switching element that is always in the disconnected state in accordance with the failure location.

  As for the disconnection detection method in the controller 22, the ratio of the conduction / disconnection period of the combination of the second and fourth switching elements 12, 14 and the input / output voltage ratio of the voltage converter 2 are the same as in the first and second embodiments. The presence of disconnection failure is detected from the relationship. In this case, which one of the second switching element 12 and the fourth switching element 14 is broken is determined according to the combination of the switching elements. When the disconnection failure of any of the second and fourth switching elements 12 and 14 is detected, the controller 22 sets both the second and fourth switching elements 12 and 14 to the normally disconnected state in response to this. If the driver 21 is controlled so that the third switching elements 11 and 13 are always in a conductive state, no problem arises because the power supply is maintained.

  The difference from the first embodiment (FIG. 3) in the process of the control unit 6 is that the switch 32 is further turned off in the generated voltage calculation process of the generator 1 when the conduction is maintained in step S106.

  The difference between the processing of the controller 22 and the first embodiment (FIG. 4) is that the disconnection failure of the fourth switching element 14 is determined in addition to the second switching element 12 in the disconnection failure determination of step S202. It is. Regarding this determination, as described above, if it is possible to determine the disconnection failure of either the second switching element 12 or the fourth switching element 14, both the second and fourth switching elements 12, 14 are always in a disconnected state. The power supply can be maintained by controlling the driver 21 so that the third switching elements 11 and 13 are always in a conductive state.

  The present invention is not limited to the configurations of the first to third embodiments described above. The first to third embodiments may be combined as appropriate without departing from the spirit of the present invention. It is possible to appropriately modify or omit the configurations of .about.3.

  For example, in the first to third embodiments, the lead battery 3 and the electric double layer capacitor 31 are used as the power storage device, but the present invention is not limited to this, and a lithium ion battery may be used. Moreover, although MOSFET is used as each switching element 11-14, it is not restricted to this, You may use other switching elements, such as IGBT. Furthermore, the voltage range to be used is about 12 to 30 V because it corresponds to the lead battery 3, but it is advantageous to increase the voltage in a power supply device that requires a large amount of power, such as a hybrid vehicle. The voltage may be increased.

1 generator, 2 voltage converter, 3 lead battery (power storage device), 4 electrical load,
5 Load feeding bus, 6 Control unit (disconnection failure detection means as an external device), 7, 8 Voltage measurement line, 9, 10 Control signal line, 11-14 Switching element,
15 inductors, 16 and 17 capacitors, 21 drivers (conduction holding means),
22 controller (disconnection failure detection means), 23, 24 voltage measurement line,
31 Electric double layer capacitor, 32 switches.

Claims (9)

In a power supply apparatus comprising voltage conversion means connected between a DC power supply and an electric load, and converting the output voltage of the DC power supply by the voltage conversion means to supply electric power to the electric load.
The voltage converting means includes a first switching element connected to a positive terminal side of the DC power source, a second switching element connected to the DC power source and a negative terminal side of the electric load, and the first and second An inductor having one terminal connected to a connection point of the switching element and the other terminal connected to the positive terminal side of the electric load, wherein the first and second switching elements are alternately turned on / off. To convert the output voltage of the DC power supply,
The characteristics of the first and second switching elements are such that when both the first and second switching elements become conductive due to an abnormality, the second switching element is broken before the first switching element. And set
A disconnection failure detecting means for detecting whether or not the second switching element is disconnected; and
And a conduction holding unit that holds the first switching element so that the first switching element is always in a conductive state when the disconnection fault detecting unit detects a disconnection fault of the second switching element. A power storage device connected in parallel to the electric load; and a voltage conversion means connected between the DC power supply and the electric load, the output voltage of the DC power supply being converted by the voltage conversion means, and the electric load. In a power supply device that supplies power to
The voltage conversion means includes a first switching element connected to the positive terminal side of the electric load, a second switching element connected to the DC power source and the negative terminal side of the electric load, and the first and second elements. An inductor having one terminal connected to the connection point of the switching element and the other terminal connected to the positive electrode terminal side of the DC power supply, and alternately conducting / disconnecting the first and second switching elements; It converts the output voltage of the DC power supply,
The characteristics of the first and second switching elements are such that when the first and second switching elements both become conductive due to an abnormality, the second switching element fails before the first switching element. And set
A disconnection failure detecting means for detecting whether or not the second switching element is disconnected; and
And a conduction holding unit that holds the first switching element so that the first switching element is always in a conductive state when the disconnection fault detecting unit detects a disconnection fault of the second switching element. The power supply apparatus according to claim 1, wherein the characteristic set in the first and second switching elements is a current withstand capability . In a power supply apparatus comprising voltage conversion means connected between a DC power supply and an electric load, and converting the output voltage of the DC power supply by the voltage conversion means to supply electric power to the electric load.
The voltage conversion means is connected in series between the first and second switching elements sequentially connected in series between the positive terminal and the negative terminal of the DC power supply, and in series between the positive terminal and the negative terminal of the electric load. A third switching element and a fourth switching element; and an inductor connected between a connection point of the first and second switching elements and a connection point of the third and fourth switching elements. The output voltage of the DC power supply is converted by alternately conducting / disconnecting a combination of four switching elements and a combination of the second and third switching elements,
When the conduction state of the combination of the first and fourth switching elements is longer than that in the normal operation state due to an abnormality, the fourth switching element may break before the first switching element. To set the characteristics of the first and fourth switching elements,
A disconnection failure detecting means for detecting whether or not the fourth switching element is disconnected; and
When the disconnection failure detecting means detects a disconnection failure of the fourth switching element, the second switching element is always disconnected according to this, and the first switching element and the third switching element are turned on. And a conduction holding means for holding the battery so as to be always in a conduction state. 5. The power supply device according to claim 4, wherein the characteristic set in the first and fourth switching elements is a current withstand capability . A power storage device connected in parallel to the electrical load,
In addition, when the conduction state of the combination of the second and third switching elements is longer than that in the normal operation state due to abnormality, the second switching element breaks down earlier than the third switching element. And setting the characteristics of the second and third switching elements to
The disconnection fault detecting means detects whether the second switching element has a disconnection fault together with the fourth switching element,
When the disconnection failure detecting unit detects a disconnection failure of the second switching element, the conduction maintaining unit always disconnects the fourth switching element in response to the disconnection failure, and the first switching element and 6. The power supply device according to claim 4, wherein the third switching element is held so as to be always in a conductive state. The power supply apparatus according to claim 6, wherein the characteristic set in the second and third switching elements is a current withstand capability . The disconnection failure detection means, according to any one of claims 1 to 7, characterized in that it comprises an external device external from the switching element of said voltage converting means for detecting whether the disconnection failure Power supply. The DC power source is a generator mounted on a vehicle, the generator, along with it is possible to vary the generator voltage, characterized in that it is a possible power generation required voltage of the electric load according The power supply device according to any one of claims 1 to 8 .

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