JP5226475B2 - DC / DC converter device and fault detection method for current sensor of the device - Google Patents

Description

  The present invention relates to a DC / DC converter device that detects a failure of a current sensor provided in a DC / DC converter device and a failure detection method of the current sensor of the device.

  A vehicle power system including a DC / DC converter that performs voltage conversion by so-called chopper control using a switching element is known (Patent Document 1). In the vehicle power system of Patent Document 1, the presence or absence of an abnormality in the current sensor is determined by comparing the amount of depression of the accelerator pedal and the output of the current sensor, and when it is determined that there is an abnormality, a predetermined conduction rate is obtained. The transistor (switching element) is controlled using the chopper signal (see Steps S10 and S14 of FIG. 2 of Patent Document 1 and paragraphs [0018] to [0020], [0026], and [0027]).

  Further, as a current sensor for detecting a current flowing through a vehicle power system, a sensor that outputs a voltage within a predetermined range during normal operation and outputs a voltage out of the predetermined range during abnormal operation when a disconnection or a short circuit occurs is known. (See FIG. 2, paragraph [0009] of Patent Document 2).

Japanese Patent Application Laid-Open No. 07-023501 Japanese Unexamined Patent Publication No. 2007-024825

  In Patent Document 1, since the accelerator pedal depression amount is compared with the output of the current sensor, the abnormality of the current sensor cannot be determined unless the accelerator pedal depression amount is changed. Moreover, since the depression amount of the accelerator pedal and the output of the current sensor do not correspond one to one, the accuracy is not sufficient.

  The method of Patent Document 2 can be used only when a disconnection or a short circuit occurs, and a current sensor or voltage sensor gain change failure (failure in which the sensor gain falls outside the allowable range) or offset change failure (sensor detection possible) Cannot cope with the failure that the output range corresponding to the range is shifted.

The present invention has been made in consideration of such a problem, and it is possible to detect with high accuracy an offset change failure (also simply referred to as an offset failure) of a current sensor of a DC / DC converter device . / DC converter apparatus and to provide a fault detection knowledge method of the current sensor of the device for the purpose of.

  The DC / DC converter device according to the present invention detects a failure of a current sensor of a DC / DC converter connected between the first power device and the second power device based on a deviation between the primary power and the secondary power. And a failure detection region setting unit that causes the failure detection unit to function except in a region where the converter passing power efficiency of the DC / DC converter is significantly reduced.

  In addition, a failure detection method for a current sensor of a DC / DC converter device according to the present invention is a failure detection method for a current sensor of a DC / DC converter device connected between a first power device and a second power device. It is determined whether or not the DC / DC converter passing power efficiency is in a region where the DC / DC converter passing power efficiency is not significantly reduced. When the DC / DC converter passing power efficiency is in a region where the DC / DC converter passing power efficiency is not significantly reduced, the current sensor is detected based on a deviation between primary power and secondary power. It is characterized by detecting a failure of

  According to each of the above-described inventions, since the failure of the current sensor is detected except for the region where the converter passing power efficiency of the DC / DC converter is significantly reduced, the failure of the current sensor can be detected with high accuracy. .

  In this case, further, when the failure of the current sensor is detected, the operation of the current limiting mode for limiting the passing current of the DC / DC converter is prohibited, and the DC / DC converter device is controlled by limiting the converter passing power. Can be protected.

  The present invention is preferably applied to a fuel cell system in which a power storage device is used as the first power device and a fuel cell is used as the second power device.

  The present invention is preferably applied to a fuel cell vehicle that includes a power storage device as the first power device, a fuel cell as the second power device, and a motor that is connected in parallel to the fuel cell and generates regenerative power. It is.

  The present invention can also be applied to an electric vehicle including a power storage device as the first power device and a motor that generates regenerative power as the second power device.

  According to the present invention, since the failure of the current sensor is detected except in the region where the converter passing power efficiency of the DC / DC converter is significantly reduced, the failure of the current sensor can be detected with high accuracy.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle or the like to which a DC / DC converter apparatus that performs a failure detection method for a current sensor of a DC / DC converter apparatus according to the present invention is applied will be described with reference to the drawings.

A. Explanation of overall configuration [Overall configuration]
FIG. 1 shows a schematic overall configuration diagram of a fuel cell vehicle 10 according to this embodiment.

  The fuel cell vehicle 10 basically includes a battery 12 as a first DC power supply device that generates a primary voltage V1 on the primary side 1S and a second DC power supply that generates a secondary voltage V2 on the secondary side 2S. A hybrid DC power supply device including a fuel cell 14 as a device, and a traveling motor 16 that is a load supplied with power from the hybrid DC power supply device.

[Fuel cell and its system]
The fuel cell 14 has, for example, a stack structure in which cells formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode from both sides are stacked. A reaction gas supply unit 18 is connected to the fuel cell 14 through a pipe. The reactive gas supply unit 18 includes a hydrogen tank that stores hydrogen (fuel gas) that is one reactive gas, and a compressor that compresses air (oxidant gas) that is the other reactive gas. A power generation current generated by an electrochemical reaction in the fuel cell 14 of hydrogen and air supplied from the reaction gas supply unit 18 to the fuel cell 14 is supplied to the motor 16 and the battery 12.

  The fuel cell system 11 includes a fuel cell 14 and a reaction gas supply unit 18 and a fuel cell control unit (FC control unit) 44 that controls them.

[DC / DC converter]
The DC / DC converter 20 is connected to a battery 12 having one side connected to the primary side 1S, and the other side is connected to a secondary side 2S, which is a connection point between the fuel cell 14 and the motor 16, and a chopper type voltage conversion. Device.

  The DC / DC converter 20 converts the primary voltage V1 into a secondary voltage V2 (V1 ≦ V2) (boost conversion), and also converts the secondary voltage V2 into a primary voltage V1 (step-down conversion). This is a voltage conversion device.

[Inverter, motor and drive system]
The inverter 22 has a three-phase full-bridge configuration, performs DC / AC conversion, converts DC to three-phase AC, and supplies it to the motor 16. On the other hand, the inverter 22 converts the DC after AC / DC conversion accompanying the regenerative operation. The secondary side 2S is supplied to the primary side 1S through the DC / DC converter 20, and the battery 12 is charged.

  The motor 16 rotates the wheels 26 through the transmission 24. In practice, the inverter 22 and the motor 16 are collectively referred to as a load 23.

[High voltage battery]
A high voltage battery 12 connected to the primary side 1S is a power storage device (energy storage), and for example, a lithium ion secondary battery or a capacitor can be used. In this embodiment, a lithium ion secondary battery is used.

[Various sensors, main switches and communication lines]
A main switch (power switch) 34 and various sensors 36 are connected to a communication line 38. The main switch 34 has a function as an ignition switch that turns on (starts or starts) and turns off (stops) the fuel cell vehicle 10 and the fuel cell system 11. Various sensors 36 detect state information, such as a vehicle state and an environmental state. As the communication line 38, a CAN (Controller Area Network) that is an in-vehicle LAN is used.

[Control unit]
The integrated control unit 40, the FC control unit 44, the motor control unit 46, the converter control unit 48, and the battery control unit 52 are connected to the communication line 38. A DC / DC converter device 50 is formed by the DC / DC converter 20 and the converter control unit 48 that controls the DC / DC converter 20.

  Each control unit 40, 44, 46, 48, 52 includes a microcomputer, detects state information of various switches such as the main switch 34 and various sensors 36, and also controls each of the control units 40, 44, 46, 48, 52. Each CPU implements various functions by inputting status information from these switches and sensors and information (commands, etc.) from other controllers, and executing programs stored in memory (ROM). It operates as a function realization unit (function realization means). The control units 40, 44, 46, 48, and 52 have an input / output interface such as a timer, an A / D converter, and a D / A converter, as necessary, in addition to a CPU and a memory.

B. Detailed configuration description [DC / DC converter device]
FIG. 2 shows a detailed configuration of the DC / DC converter 20. The DC / DC converter 20 includes a phase arm UA disposed between the primary side 1S and the secondary side 2S, and a reactor 90.

  The phase arm UA includes an upper arm element (upper arm switching element 81 and diode 83) and a lower arm element (lower arm switching element 82 and diode 84).

  As the upper arm switching element 81 and the lower arm switching element 82, for example, a MOSFET or an IGBT is employed.

  Reactor 90 is inserted between the midpoint (common connection point) of phase arm UA and the positive electrode of battery 12, and converts voltage between primary voltage V1 and secondary voltage V2 by DC / DC converter 20. In particular, it has the function of releasing and storing energy.

  The upper arm switching element 81 is turned on by the high level of the gate drive signal (drive voltage) UH output from the converter control unit 48, and the lower arm switching element 82 is turned on by the high level of the gate drive signal (drive voltage) UL. To turn them on. The converter control unit 48 detects the primary voltage V1 by the voltage sensor 91 provided in parallel with the primary side smoothing capacitor 94, detects the primary current I1 by the current sensor 101, and detects the secondary side smoothing capacitor 96. The secondary voltage V2 is detected by a voltage sensor 92 provided in parallel with the current sensor 102, and the secondary current I2 is detected by a current sensor 102.

  A temperature sensor 69 is attached to each of the upper arm switching element 81 and the lower arm switching element 82, and the detected temperatures Tuh (81) and Tul (82) of the upper arm switching element 81 and the lower arm switching element 82 are converted into converters, respectively. It is detected by the control unit 48.

[Operation of DC / DC converter device]
The DC / DC converter device 50 operates by (a) step-down chopper control and step-up chopper control by synchronous switching processing. In this embodiment, the operation mode includes (b) secondary voltage V2 control mode and (c) 1 It operates in the next current I1 limit mode.

(A) Step-down chopper control and step-up chopper control by synchronous switching processing In step-down chopper control related to step-down operation (regenerative operation), the secondary current I2 flowing out from the load 23 and the fuel cell 14 passes through the DC / DC converter 20 and becomes 1 The battery 12 is charged as the next current I1. Basically, when the upper arm switching element 81 is on and the lower arm switching element 82 is off, energy is accumulated in the reactor 90 by the secondary current I2, and when the upper arm switching element 81 is turned off, the diode 84 Flows through and the energy accumulated in the reactor 90 is released, and the battery 12 and the like are charged by the primary current I1.

  On the other hand, in the step-up chopper control related to the step-up operation (power running operation), the primary current I1 flowing out from the battery 12 passes through the DC / DC converter 20 and the load 23 including the motor 16 is driven as the secondary current I2. Basically, when the upper arm switching element 81 is off and the lower arm switching element 82 is on, energy is accumulated in the reactor 90 by the primary current I1 from the battery 12, and the lower arm switching element 82 is turned off. When the diode 83 flows, the energy accumulated in the reactor 90 is released, and the load 23 is driven by the current flowing from the primary side 1S to the secondary side 2S.

  As shown in FIGS. 3 and 4, the step-down chopper control and the step-up chopper control are used in combination in each switching period Tsw. That is, in each switching cycle Tsw, both the drive time T1 of the upper arm switching element 81 and the drive time T2 of the lower arm switching element 82 appear, and the upper arm switching element 81 and the lower arm switching element 82 are driven alternately. . As described above, the process of alternately driving the upper arm switching element 81 and the lower arm switching element 82 for each switching period Tsw is referred to as a synchronous switching process.

  Between the upper arm switching element driving time T1 and the lower arm switching element driving time T2, in order to prevent the secondary voltage V2 from being short-circuited by simultaneously driving the upper arm switching element 81 and the lower arm switching element 82. The dead time dt is arranged.

  3 and 4, in the waveforms of the drive signals UH and UL, the hatched period is a period during which the upper arm switching element 81 to which the drive signals UH and UL are supplied is on (actual current flows). Period) and a period during which the lower arm switching element 82 is turned on (period during which current actually flows).

  3 and 4 show time charts of the primary current I1 during the step-down operation of the DC / DC converter 20. FIG. 3 and 4, the sign of the primary current I1 flowing through the reactor 90 is positive (+) and the secondary current when the boosting current (discharge current from the battery 12) flowing from the primary side 1S to the secondary side 2S is positive. The step-down current (charging current to the battery 12) flowing from 2S to the primary side 1S is negative (-).

  In this embodiment, the ratio of the upper arm switching element driving time T1 in one switching cycle Tsw is defined as the duty ratio DUT (DUT = T1 / Tsw). Here, the duty ratio DUT in the secondary voltage V2 control mode can be defined as the primary voltage V1 detected by the voltage sensor 61 divided by the target secondary voltage V2tar (V1 / V2tar) (DUT = V1 / V2tar). In general, since the proportion of the dead time dt in the switching cycle Tsw is small, the proportion of the lower arm element driving time T2 in one switching cycle Tsw is “1-DUT” and “1- (V1 / V2tar). ) ".

(B) Secondary voltage V2 control mode Since the fuel cell 14 has a characteristic that is uniquely determined such that the value of the generated current that gradually flows out in accordance with the rise of the inter-terminal voltage, in this case, the secondary voltage V2, gradually decreases. Feedback control of the secondary voltage V2 by the converter control unit 48 can meet the required power of the load 23. The required power of the load 23 is the required power of the motor 16, and the shortage with respect to the required power of the motor 16 is covered (assisted) by the discharge current from the battery 12.

(C) Primary current I1 restriction mode When an excessive discharge current or an excessive charging current flows to the battery 12, the battery 12 is likely to deteriorate. Therefore, a current threshold value Ith that prevents such an excessive discharge current and an excessive charge current from flowing through the battery 12 is determined, and the charge / discharge current of the battery 12 flows through the current sensor 101 so as not to exceed the current threshold value Ith. In this mode, the primary current I1 is monitored, and the primary current I1 is limited to a predetermined current or less by feedback control by the converter control unit 48. During the operation in the primary current I1 limiting mode, the feedback control of the secondary voltage V2 is not performed, so the value of the secondary voltage V2 becomes free.

[Function realization part of converter control part]
The converter control unit 48 functions as a function realizing unit, a failure detection unit 202 that detects a failure of the current sensors 101 and 102 based on a deviation between the primary side power P1 and the secondary side power P2, and the failure detection unit 202 as a DC / DC. When the failure detection area setting unit 204 that functions except for a region where the converter passing power efficiency η of the DC converter 20 is significantly reduced and the failure detection unit 202 detects a failure of the current sensors 101 and 102 , the DC / DC converter 20 In the current limiting mode for limiting the passing current It (passing power Pt), in this embodiment, the operation in the primary current I1 limiting mode described above is prohibited, and the operation prohibiting power limiting unit 206 for limiting the converter passing power Pt Have.

  Further, the converter control unit 48 is set with a failure detection confirmed elapsed time measuring unit (abnormal progress counter / timer) 208 that measures an elapsed time Cn for determining failure detection, and various threshold values.

[Description of converter passing power and efficiency of DC / DC converter]
The primary side 1S power (primary side power) P1 is calculated by P1 = I1 × V1, and the secondary side 2S power (secondary side power) P2 is calculated by P2 = I2 × V2.

  The converter passing power Pt is defined as Pt = P2 when power is supplied from the primary side 1S to the secondary side 2S, that is, in the discharge direction of the battery 12, and the secondary side 2S to the primary side 1S. When electric power is supplied to the battery 12, that is, in the charging direction of the battery 12, Pt = P1 is defined.

  The converter passing power efficiency η [%] is ηd = (P2 / P1) × 100 [%] when electric power is supplied from the primary side 1S to the secondary side 2S, that is, in the discharging direction of the battery 12. When the electric power is supplied from the secondary side 2S to the primary side 1S, that is, in the charging direction to the battery 12, it is calculated as ηc = (P1 / P2) × 100.

  FIG. 5 shows an example of an actual measurement result of the converter passing power efficiency η. FIG. 5 also shows the failure detection area Dde set by the failure detection area setting unit 204 and the failure non-detection area Dnde. The failure non-detection region Dnde is simultaneously set as a limited region of the converter passing power Pt by the operation prohibiting power limiting unit 206.

  Further, in FIG. 5, the horizontal axis represents the primary power (output) P1 [kW] and the predetermined power [kW] normalized to the value “1”. The value “2” means twice the predetermined power.

  Note that, as described above, the power P1 [kW] is positive when the battery 12 is discharged {a state in which the primary current I1 (I1> 0) is flowing out from the battery 12}, and negative when charging { The value of the state in which the primary current I1 (I1 <0) is flowing into the battery 12 is set.

  As can be seen from FIG. 5, the efficiency η [%] of the converter passing power Pt is high in the failure detection region Dde in which the absolute value of the primary power P1 exceeds the power threshold P1th, and the primary side In the failure non-detection region Dnde where the absolute value of the electric power P1 does not exceed the electric power threshold value P1th, the absolute value of the electric power P1 decreases significantly toward the zero value of the primary power P1.

C. Description of Operation An embodiment of a failure detection method for the current sensors 101 and 102 of the DC / DC converter device 50 will be described with reference to the flowcharts of FIGS.

  When detecting a failure of the current sensors 101, 102, first, in step S1, the converter control unit 48 operates the secondary voltage V2 during operation with the main switch 34 of the fuel cell vehicle 10 turned on. It is determined whether or not the DC / DC converter device 50 is operating in the control mode. In the secondary voltage V2 control mode, the secondary voltage V2 is controlled to the target secondary voltage V2tar, so that it is easy to detect a failure.

  During the operation in the secondary voltage V2 control mode, in step S2, it is determined whether or not the current sensors 101 and 102 have determined the offset abnormality.

  Next, in step S3, it is determined whether or not any of the detected primary voltage V1, detected secondary voltage V2, primary side current sensor 101, and secondary side current sensor 102 is abnormal.

  Next, in step S4, it is determined whether or not the primary current I1 is positive (I1> 0). If it is positive, the failure determination by the processing from step S5 is continued, and if it is negative, the failure determination by the processing from step 25 is continued.

  In step S5, the primary power P1 is calculated from the product of the primary voltage V1 and the primary current I1 (P1 ← V1 × I1).

  Next, in step S6, it is determined whether or not the calculated primary power P1 is in the failure detection region Dde (P1> P1th).

When in the failure detection area Dde , in step S7, the secondary power P2 is calculated from the product of the secondary voltage V2 and the secondary current I2 (P2 ← V2 × I2).

  Next, in step S8, a power deviation value ΔP (ΔP = P1-P2) is calculated, and the calculated power deviation value ΔP is set as a temporary variable y {y ← (P1-P2)}.

  In step S9, it is determined whether or not the value of the temporary variable y is positive. If the value is positive, in step S10, the temporary variable y is set as the power deviation value ΔP (positive value) (ΔP ← y). In step S9, if the value of temporary variable y is negative, in step S11, the sign of temporary variable y is inverted and set as power deviation value ΔP (ΔP ← −y).

  Next, in step S12, it is determined whether or not the measured and calculated power deviation value ΔP is equal to or greater than a predetermined power deviation threshold (power deviation abnormality determination threshold) Pth (ΔP ≧ Pth). .

  If the power deviation value ΔP exceeds the power deviation threshold value Pth, the influence of noise or the like is taken into consideration, and it is not immediately determined to be abnormal. In step S13, the count value Cn of the abnormal elapsed counter / timer 208 (in practice, It is determined whether or not (count value × sampling time = abnormal elapsed time) exceeds the elapsed time threshold Tth (Cn ≧ Tth).

  In step S13, the count value Cn of the abnormality progress counter / timer 208 is incremented by one unit in step S14 (Cn ← Cn + 1).

Thereafter, Steps S1 to S13: NO and Step S14 are repeated a predetermined number of times. When Step S13 is established (Cn ≧ Tth), it is determined in Step S15 that the current sensor 101 has an offset failure.

  Steps S1 to S13: If step S12 is not established during the repetition of the NO process, the count value Cn of the abnormality progress counter / timer 208 is set in step S16 in order to redo the failure detection from the beginning. Reset to 0 (Cn ← 0).

  If the primary power P1 is equal to or less than the power threshold P1th for determining failure of the current sensors 101 and 102 in the determination in step S6 described above (P1 ≦ P1th), the current sensors 101 and 102 In step S17, the count value Cn of the abnormality progress counter / timer 208 is reset (Cn ← 0) and the calculated power deviation value ΔP is reset (ΔP ← 0).

  Further, even if any of the values is abnormal in the determination in step S3, the count value Cn of the abnormality elapsed counter / timer 208 is reset (Cn ← 0) and the power deviation value ΔP is reset in step S17. (ΔP ← 0).

  Next, when the primary current I1 is not positive (I1> 0) but negative in step S4, the primary power P1 having a positive value is calculated in step S25 {P1 ← − ( V1 × I1)}.

  Next, processing similar to the processing in steps S6 to S17 described above is performed in steps S26 to S37.

  In step S26, it is determined whether or not the primary power P1 is in the failure detection area Dde (P1> P1thp).

  In step S27, the secondary power P2 is calculated {P2 ← − (V2 × I2)}.

  In step S28, a power deviation value ΔP (P1-P2) is calculated, and the calculated power deviation value ΔP is set as a temporary variable y {y ← (P1-P2)}.

  In step S29, it is determined whether or not the value of the temporary variable y is positive. If the value is positive, in step S30, the temporary variable y is set as the power deviation value ΔP (positive value) (ΔP ← y). In step S29, if the value of temporary variable y is negative, in step S31, the sign of temporary variable y is inverted and set as power deviation value ΔP (ΔP ← −y).

  Next, in step S32, it is determined whether or not the power deviation value ΔP is equal to or greater than a power deviation threshold value (power deviation abnormality determination threshold value) Pth (ΔP ≧ Pth).

  If the power deviation value ΔP exceeds the power deviation threshold value Pth, it is determined in step S33 whether or not the elapsed time threshold value Tth is exceeded (Cn ≧ Tth).

  In the first determination, step S33 is not established. Therefore, in step S34, the count value Cn of the abnormal progress counter / timer 208 is increased by one unit (Cn ← Cn + 1).

Thereafter, Steps S1 to S4: NO, S25 to S33: NO, and S34 are repeated a predetermined number of times. When Step S33 is established (Cn ≧ Tth), it is determined in Step S34 that the current sensor 101 has an offset failure.

  In addition, when step S12 is not established during the repetition of the processes of steps S1 to S4: NO, S25 to S33: NO, and S34, in order to restart the failure detection from the beginning, in step S16, the abnormality progress counter Reset the count value Cn of the timer 208 to 0 (Cn ← 0).

  If the primary power P1 is equal to or less than the power threshold P1th for determining the failure of the current sensors 101 and 102 in the determination in step S26 described above, the abnormal progress counter / timer 208 is determined in step S37. The count value Cn is reset (Cn ← 0) and the power deviation value ΔP is reset (ΔP ← 0).

According to the above-described embodiment, the DC / DC converter device 50 detects the failure of the current sensors 101 and 102 of the DC / DC converter connected between the battery 12 and the fuel cell 14 with the primary power P1 and the secondary power. The failure detection unit 202 that detects the deviation value ΔP of the side power P2 and the failure detection unit 202 except for the failure non-detection region Dnde, which is a region where the converter passing power efficiency η of the DC / DC converter 20 is significantly reduced, A failure detection area setting unit 204 that functions in the failure detection area Dde.

Thus, since so as to detect a failure of the current sensor 101, 102 with the exception of the area where the converter passing power efficiency η of the DC / DC converter 20 is remarkably reduced, accurately detecting a failure of the current sensor 101, 102 can do.

In this case, when the failure of the current sensors 101 and 102 is further detected, the operation of the above-described primary current I1 restriction mode for restricting the passing current of the DC / DC converter 20 is prohibited, and the converter passing power Pt is not failed. By limiting the power value within the detection region Dnde, the DC / DC converter device 50 can be protected.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the contents described in this specification.

  For example, as shown in FIG. 9, the present invention can also be applied to an electric vehicle 13 including a battery 12 as a first power device and a motor 16 that generates regenerative power as a second power device.

1 is a schematic overall configuration diagram of a fuel cell vehicle according to an embodiment of the present invention. It is a circuit diagram which shows the detailed structure of the DC / DC converter which concerns on this embodiment. 3 is a time chart for explaining step-down operation of a DC / DC converter. 6 is a time chart for explaining a step-up operation of the DC / DC converter. It is explanatory drawing of the efficiency of converter passage power. It is a flowchart of a current sensor failure detection. It is a flowchart of a current sensor failure detection. It is a flowchart of a current sensor failure detection. It is explanatory drawing of the electric vehicle which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell vehicle 11 ... Fuel cell system 12 ... Battery 14 ... Fuel cell 16 ... Motor 20 ... DC / DC converter 48 ... Converter control part 50 ... DC / DC converter apparatus

Claims (5)

A converter control unit that feedback-controls a secondary voltage that is a voltage between terminals of the second power device of a DC / DC converter connected between the first power device and the second power device ;
A failure detection unit for detection known offset failure of the secondary current sensor for detecting the secondary current of the primary current sensor or the DC / DC converter for detecting a primary current of the DC / DC converter,
The failure detection unit, have a, and failure detection area setting unit to function except an area where the converter passing power efficiency of the DC / DC converter is reduced remarkably,
The failure detection unit detects the offset failure of the primary current sensor and the secondary current sensor, and when the converter control unit performs feedback control of the secondary voltage, the secondary voltage and the first current sensor are detected. After confirming that the primary voltage, which is the voltage between terminals of the power device, is not abnormal, the primary power represented by the product of the primary current and the primary voltage, the secondary current, and the secondary voltage A DC / DC converter device that detects that the primary current sensor or the secondary current sensor is an offset failure when the deviation from the secondary power expressed by the product of is greater than a threshold value . The DC / DC converter device according to claim 1, wherein
Further, when the failure detection unit detects a failure of the primary current sensor or the secondary current sensor , the operation of the current limiting mode for limiting the passing current of the DC / DC converter is prohibited and the converter passing power is limited. A DC / DC converter device comprising an operation prohibiting power limiting unit.   The fuel cell system, wherein the first power device according to claim 1 or 2 is a power storage device, and the second power device is a fuel cell.   3. The fuel cell vehicle according to claim 1, wherein the first power device is a power storage device, and the second power device includes a fuel cell and a motor that is connected in parallel to the fuel cell and generates regenerative power. . In a failure detection method for detecting an offset failure of a primary current sensor or a secondary current sensor of a DC / DC converter device connected between a first power device and a second power device,
Determining whether a secondary voltage, which is a voltage between terminals of the second power device, is feedback-controlled,
When feedback control is being performed, it is confirmed whether or not the secondary voltage and the primary voltage that is the voltage between the terminals of the first power device are abnormal.
When the secondary voltage and the primary voltage are not abnormal, it is determined whether or not the DC / DC converter passing power efficiency is in a region that does not significantly decrease,
When the DC / DC converter passing power efficiency is in a region that does not significantly decrease, it is represented by the product of the primary power, the secondary current, and the secondary voltage represented by the product of the primary current and the primary voltage. When the deviation from the secondary power is larger than the threshold value, it is detected that the primary current sensor or the secondary current sensor is an offset failure. A method for detecting a failure of a current sensor of a DC / DC converter device, wherein:

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