JP2011109849A - Device for controlling power supply system, and vehicle mounting the same - Google Patents

Abstract

In a control device of a power supply system, the reliability of a converter is improved by detecting an abnormality of a current sensor for detecting a current flowing through a reactor of a converter without adding parts.
A power system includes a power storage device, a battery current sensor that detects a current flowing through the power storage device, a converter having a reactor, and a reactor current sensor that detects a current flowing through the reactor. Including. Control device 30 includes a current control unit 220 that adjusts to a target current that detects the current flowing through reactor L1 by feedback control, and a drive command generation unit 230 that generates a drive command for converter 12 based on the control output of current control unit 220. And a current monitoring value detected by the battery current sensor 11 and a current detection value detected by the reactor current sensor 18, a sensor monitoring unit configured to detect an abnormality in the reactor current sensor 18 280.
[Selection] Figure 1

Description

  The present invention relates to a control device for a power supply system and a vehicle equipped with the control device, and more particularly, to an abnormality detection technique for a current sensor included in the power supply system.

  2. Description of the Related Art In recent years, as an environmentally-friendly vehicle, an electric vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels using a driving force generated from electric power stored in the power storage device has attracted attention. Examples of the electric vehicle include an electric vehicle, a hybrid vehicle, and a fuel cell vehicle.

  In these electric vehicles, a rotating electrical machine that receives electric power from the power storage device when starting or accelerating to generate driving force for traveling, and generates electric power by regenerative braking during braking to store electric energy in the power storage device. (Motor generator) may be provided. Thus, in order to control a motor generator according to a driving | running | working state, an inverter is mounted in an electric vehicle.

  In such an electric vehicle, the electric power required by the inverter varies depending on the vehicle state. In some cases, a converter is provided between the power storage device and the inverter in order to stably supply power required by the inverter. With this converter, the inverter input voltage can be made higher than the output voltage of the power storage device to increase the output of the motor and reduce the motor current at the same output, thereby reducing the size and cost of the inverter and motor. Can be achieved.

  Japanese Patent Laying-Open No. 2007-185043 (patent document 1) discloses that in a hybrid vehicle, a current sensor for detecting a current of each phase flowing through a motor generator is duplexed for each phase, and a detection value of the duplexed current sensor is disclosed. A technique for detecting an abnormality of a current sensor by comparing each other is disclosed.

JP 2007-185043 A JP 2005-245067 A JP 2005-027379 A JP 2006-020401 A JP 2008-172952 A JP 2009-148139 A JP 2006-143028 A JP 2000-134716 A

  In an electric vehicle, in order to control the converter efficiently, a current sensor for detecting a current flowing through a reactor included in the converter may be provided.

  As for the current sensor for detecting the current flowing through the reactor of this converter, it is possible to apply a technique for duplicating the sensor as in Japanese Patent Application Laid-Open No. 2007-185043 (Patent Document 1). By doing in this way, it can control that damage and degradation of a device occur because of the influence of the excessive current and voltage which occur by controlling a converter based on incorrect sensor information.

  However, when the technique disclosed in Japanese Patent Application Laid-Open No. 2007-185043 (Patent Document 1) is applied, the number of parts increases because the sensor is duplicated. This may increase the size of the device and increase the cost.

  The present invention has been made to solve such a problem, and an object of the present invention is to detect an abnormality of a current sensor for detecting a current flowing through a reactor of a converter without adding parts. Thus, it is an object of the present invention to provide a control device for a power supply system capable of improving the reliability of a converter and a vehicle equipped with the control device.

  A power supply system control device according to the present invention is a power supply system control device for supplying power to a load device. The power supply system includes a chargeable power storage device, first and second current sensors, and a converter. Including. The first current sensor detects a current input / output to / from the power storage device. The converter includes a reactor and is configured to be capable of voltage conversion between the power storage device and the load device. The second current sensor detects a current flowing through the reactor. The control device also includes a voltage control unit, a current control unit, a drive command generation unit, and a sensor monitoring unit. The voltage controller adjusts the voltage on the load device side of the converter to the target voltage by feeding back the voltage on the load device side of the converter. The current control unit adjusts the current flowing through the reactor to the target current by feeding back the detection value of the second current sensor based on the control output of the voltage control unit. The drive command generation unit generates a drive command for the converter based on the control output of the current control unit. The sensor monitoring unit detects an abnormality of the second current sensor based on a comparison between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor. .

  Preferably, the sensor monitoring unit has an absolute value of a difference between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor larger than a predetermined threshold value. Is detected, it is determined that the second current sensor is abnormal.

  Preferably, the sensor monitoring unit is in a state where the absolute value of the difference between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor is larger than the threshold value. When continuing for a predetermined period, it determines with a 2nd current sensor being abnormal.

  Preferably, the control device further includes a smoothing unit configured to smooth the current detection value detected by the second current sensor in the time axis direction. Then, the sensor monitoring unit compares the detection value of the second current sensor smoothed by the smoothing unit with the current detection value detected by the first current sensor.

  Preferably, when detecting an abnormality of the second current sensor, the control device controls the converter without using the current detection value detected by the second current sensor.

  Preferably, the converter includes a first switching element and a second switching element connected in series between the power line of the load device and the ground line, and a first switching element with a direction from the ground line toward the power line as a forward direction. A first rectifier element and a second rectifier element connected in parallel to the element and the second switching element, respectively. The reactor is inserted in a path connecting the connection node of the first switching element and the second switching element and the positive electrode terminal of the power storage device. When the abnormality of the second current sensor is detected, the drive command generation unit fixes the first switching element in the on state and fixes the second switching element in the off state. Is generated.

  Preferably, when an abnormality of the second current sensor is detected, the drive command generation unit generates a drive command based on the control output of the voltage control unit instead of the control output of the current control unit.

  Preferably, when an abnormality of the second current sensor is detected, the current control unit performs feedback control using the detection value of the first current sensor instead of the detection value of the second current sensor.

  Preferably, the voltage control unit decreases a control gain used for feedback control when an abnormality of the second current sensor is detected.

  Preferably, the voltage control unit decreases the upper limit value for limiting the target voltage when an abnormality of the second current sensor is detected.

  A vehicle according to the present invention includes a chargeable power storage device, first and second current sensors, a driving force generation unit, a converter, and a control device for controlling the converter. The first current sensor detects a current input / output to / from the power storage device. The driving force generation unit is configured to generate driving force using electric power from the power storage device. The converter includes a reactor and is configured to be capable of voltage conversion between the power storage device and the driving force generator. The second current sensor detects a current flowing through the reactor. The control device includes a voltage control unit, a current control unit, a drive command generation unit, and a sensor monitoring unit. The voltage controller adjusts the voltage on the load device side of the converter to the target voltage by feeding back the voltage on the load device side of the converter. The current control unit adjusts the current flowing through the reactor to the target current by feeding back the detection value of the second current sensor using the control output of the voltage control unit as the target current. The drive command generation unit generates a drive command for the converter based on the control output of the current control unit. The sensor monitoring unit detects an abnormality of the second current sensor based on a comparison between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor. .

  According to the present invention, in a control device for a power supply system and a vehicle equipped with the control device, an abnormality of a current sensor for detecting a current flowing through a reactor of a converter can be detected without adding parts. Reliability can be improved.

1 is an overall block diagram of a hybrid vehicle equipped with a motor drive control system to which a control device for a power supply system according to the present embodiment is applied. It is the figure which showed the characteristics of the reactor current IL and the battery current IB. It is the figure which showed an example of the time change of the electric current which flows through a current sensor. In this Embodiment, it is a functional block diagram for demonstrating the sensor abnormality detection control performed by ECU. It is a figure for demonstrating an example of the smoothing process performed in a smoothing part. It is a figure which shows an example of a primary delay filter. It is a figure for demonstrating the other example of the smoothing process performed in a smoothing part. It is a figure for demonstrating the further another example of the smoothing process performed in a smoothing part. 4 is a flowchart for illustrating details of a sensor abnormality detection control process executed by an ECU in the first embodiment. 7 is a flowchart for explaining details of a sensor abnormality detection control process executed by an ECU in a modification of the first embodiment. It is a figure for demonstrating the state of the system voltage VH by the difference in control of a converter. In Embodiment 2, it is a functional block diagram for demonstrating the switching control performed by ECU. In Embodiment 2, it is a flowchart for demonstrating the detail of the switching control process performed by ECU. FIG. 11 is a functional block diagram for illustrating switching control executed by an ECU in a modification of the second embodiment. In Embodiment 3, it is a functional block diagram for demonstrating the gain change control performed by ECU. In Embodiment 3, it is a flowchart for demonstrating the detail of the gain change control process performed by ECU. In Embodiment 4, it is a functional block diagram for demonstrating the change control of the voltage command performed by ECU. In Embodiment 4, it is a flowchart for demonstrating the detail of the change control process of the voltage command performed with ECU. FIG. 11 is a functional block diagram when Embodiment 4 is applied to Embodiment 3. In Embodiment 5, it is a functional block diagram for demonstrating the sensor selection control performed by ECU. In Embodiment 5, it is a flowchart for demonstrating the detail of the sensor selection control process performed by ECU.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the same or equivalent part in a figure, the same code | symbol is attached | subjected and the description is not repeated.

[Embodiment 1]
FIG. 1 is an overall block diagram of a hybrid vehicle 100 equipped with a motor drive control system to which a control device for a power supply system according to the present embodiment is applied. In the present embodiment, a hybrid vehicle equipped with an engine and a motor generator will be described as an example of vehicle 100. However, the configuration of vehicle 100 is not limited to this, and the vehicle can travel with electric power from the power storage device. If so, it is applicable. The vehicle 100 includes, for example, an electric vehicle and a fuel cell vehicle in addition to the hybrid vehicle.

  Referring to FIG. 1, vehicle 100 includes a power supply system 20, a load device 45, a smoothing capacitor C <b> 2, and a control device (hereinafter also referred to as ECU “Electronic Control Unit”) 30.

  Power supply system 20 includes a power storage device 28, system relays SR1 and SR2, a smoothing capacitor C1, and a converter 12.

  The power storage device 28 is typically configured to include a power storage device such as a secondary battery such as nickel hydride or lithium ion or an electric double layer capacitor. DC voltage VB output from power storage device 28 and DC current IB input / output are detected by voltage sensor 10 and current sensor 11 (hereinafter also referred to as “battery current sensor”), respectively. Voltage sensor 10 and current sensor 11 output detected values of detected DC voltage VB and DC current IB to ECU 30. The output voltage of power storage device 28 is, for example, about 200V.

  System relay SR1 is inserted in a path connecting positive electrode terminal of power storage device 28 and power line PL1. System relay SR2 is interposed in a path connecting negative electrode terminal of power storage device 28 and ground line NL. System relays SR <b> 1 and SR <b> 2 are controlled by a signal SE from ECU 30, and switch between supply and interruption of power from power storage device 28 to converter 12.

  Converter 12 includes a reactor L1, switching elements Q1, Q2, and diodes D1, D2.

  Switching elements Q1 and Q2 are connected in series between power line PL2 and ground line NL. Switching elements Q1 and Q2 are controlled by a switching control signal PWC from ECU 30. In the present embodiment, IGBTs (Insulated Gate Bipolar Transistors), power MOS (Metal Oxide Semiconductor) transistors, or power bipolar transistors are used as switching elements Q1 and Q2 and switching elements Q3 to Q8 described later. it can. Anti-parallel diodes D1 and D2 are arranged for switching elements Q1 and Q2.

  Reactor L1 has one end connected to a connection node of switching elements Q1 and Q2, and the other end connected to power line PL1. Smoothing capacitor C1 is connected between power line PL1 and ground line NL, and reduces voltage fluctuation between power line PL1 and ground line NL.

  Current sensor 18 (hereinafter also referred to as “reactor current sensor”) detects a reactor current flowing through reactor L1, and outputs the detected value IL to ECU 30. The voltage sensor 19 detects the voltage applied to the smoothing capacitor C1, and outputs the detected value VL to the ECU 30.

  The power supply system 20 further includes an air conditioner 50, a DC / DC converter 51, an auxiliary load 52, and an auxiliary battery 53 as a low voltage system (auxiliary system).

  Air conditioner 50 is connected to power line PL1 and ground line NL. The air conditioner 50 is driven using the electric power reduced by the converter 12 or the electric power supplied from the power storage device 28, and air-conditions the interior of the vehicle.

  DC / DC converter 51 is connected to power line PL1 and ground line NL, and further steps down the DC voltage stepped down by converter 12 or the DC voltage supplied from power storage device 28 to auxiliary load 52 and auxiliary battery 53. Supply.

  Auxiliary battery 53 is typically formed of a lead storage battery. The output voltage of auxiliary battery 53 is lower than the output voltage of power storage device 28, for example, about 12V.

  The auxiliary machine load 52 includes, for example, lamps, wipers, heaters, audio, a navigation system, and the like.

  Load device 45 includes an inverter 23, motor generators MG <b> 1 and MG <b> 2, an engine 40, a power split mechanism 41, and drive wheels 42. Inverter 23 includes an inverter 14 for driving motor generator MG1 and an inverter 22 for driving motor generator MG2. As shown in FIG. 1, it is not essential to provide two sets of inverters and motor generators. For example, only one set of inverter 14 and motor generator MG1 or inverter 22 and motor generator MG2 may be provided.

  Motor generators MG1 and MG2 receive AC power supplied from inverter 23 and generate a rotational driving force for traveling the vehicle. Motor generators MG1 and MG2 receive rotational force from the outside, generate AC power according to a regenerative torque command from ECU 30, and generate regenerative braking force in vehicle 100.

  Motor generators MG1 and MG2 are also coupled to engine 40 via power split mechanism 41. Then, the driving force generated by engine 40 and the driving force generated by motor generators MG1, MG2 are controlled to have an optimal ratio. Alternatively, either one of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator. In the present embodiment, motor generator MG1 functions exclusively as a generator driven by engine 40, and motor generator MG2 functions exclusively as an electric motor that drives drive wheels 42.

  For power split mechanism 41, for example, a planetary gear mechanism (planetary gear) is used to distribute the power of engine 40 to both drive wheels 42 and motor generator MG1.

  Inverter 14 receives the boosted voltage from converter 12, and drives motor generator MG1 to start engine 40, for example. Inverter 14 also outputs regenerative power generated by motor generator MG <b> 1 by mechanical power transmitted from engine 40 to converter 12. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit.

  Inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17 provided in parallel between power line PL2 and ground line NL. Each phase arm includes a switching element connected in series between power line PL2 and ground line NL. For example, U-phase arm 15 includes switching elements Q3 and Q4, V-phase arm 16 includes switching elements Q5 and Q6, and W-phase arm 17 includes switching elements Q7 and Q8. Antiparallel diodes D3 to D8 are connected to switching elements Q3 to Q8, respectively. Switching elements Q3 to Q8 are controlled by a switching control signal PWI1 from ECU 30.

  Typically, motor generator MG1 includes a three-phase permanent magnet type synchronous motor, and one end of three coils of U, V, and W phases is commonly connected to a neutral point. Furthermore, the other end of each phase coil is connected to the connection node of the switching element in each phase arm 15-17.

Inverter 22 is connected to converter 12 in parallel with inverter 14.
Inverter 22 converts the DC voltage output from converter 12 into three-phase AC and outputs the same to motor generator MG2 that drives drive wheels. Inverter 22 also outputs regenerative power generated by motor generator MG2 to converter 12 along with regenerative braking. At this time, converter 12 is controlled by ECU 30 to operate as a step-down circuit. Although the internal configuration of inverter 22 is not shown, it is similar to inverter 14, and detailed description will not be repeated.

  Converter 12 is basically controlled such that switching elements Q1 and Q2 are turned on and off in a complementary manner in each switching period. During the boosting operation, converter 12 boosts DC voltage VL across smoothing capacitor C1 to DC voltage VH (this DC voltage corresponding to the input voltage to inverter 14 is hereinafter also referred to as “system voltage”). This boosting operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q2 to power line PL2 via switching element Q1 and antiparallel diode D1.

  Converter 12 steps down DC voltage VH to DC voltage VL during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy stored in reactor L1 during the ON period of switching element Q1 to ground line NL via switching element Q2 and antiparallel diode D2.

  The voltage conversion ratio (the ratio of VH and VL) in these step-up and step-down operations is controlled by the on-period ratio (duty) of the switching elements Q1 and Q2 in the switching period. If switching elements Q1 and Q2 are fixed to ON and OFF, respectively, VH = VL (voltage conversion ratio = 1.0) can be obtained.

  Smoothing capacitor C <b> 2 is connected between power line PL <b> 2 and ground line NL, smoothes the DC voltage from converter 12, and supplies the smoothed DC voltage to inverter 23. The voltage sensor 13 detects the voltage across the smoothing capacitor C2, that is, the system voltage VH, and outputs the detected value to the ECU 30.

  When the torque command value of motor generator MG1 is positive (TR1> 0), inverter 14 has switching elements Q3 to Q8 responding to switching control signal PWI1 from ECU 30 when a DC voltage is supplied from smoothing capacitor C2. By the switching operation, motor generator MG1 is driven so as to convert a DC voltage into an AC voltage and output a positive torque. Further, when the torque command value of motor generator MG1 is zero (TR1 = 0), inverter 14 converts the DC voltage into the AC voltage and the torque becomes zero by the switching operation in response to switching control signal PWI1. In this manner, motor generator MG1 is driven. Thus, motor generator MG1 is driven to generate zero or positive torque designated by torque command value TR1.

  Further, during regenerative braking of vehicle 100, torque command value TR1 of motor generator MG1 is set negative (TR1 <0). In this case, inverter 14 converts the AC voltage generated by motor generator MG1 into a DC voltage by a switching operation in response to switching control signal PWI1, and converts the converted DC voltage (system voltage) through smoothing capacitor C2. To the converter 12. The regenerative braking here refers to braking with regenerative power generation when the driver operating the electric vehicle performs a footbrake operation, or regenerative braking by turning off the accelerator pedal while driving, although the footbrake is not operated. This includes decelerating (or stopping acceleration) the vehicle while generating electricity.

  Similarly, inverter 22 receives switching control signal PWI2 from ECU 30 corresponding to the torque command value of motor generator MG2 and converts the DC voltage into an AC voltage by a switching operation in response to switching control signal PWI2 to obtain a predetermined torque. Motor generator MG2 is driven so that

  Current sensors 24 and 25 detect motor currents MCRT1 and MCRT2 flowing through motor generators MG1 and MG2, and output the detected motor currents to ECU 30. Since the sum of the instantaneous values of the currents of the U-phase, V-phase, and W-phase is zero, the current sensors 24 and 25 are arranged to detect the motor current for two phases as shown in FIG. All you need is enough.

  Rotation angle sensors (resolvers) 26 and 27 detect rotation angles θ1 and θ2 of motor generators MG1 and MG2, and output the detected rotation angles θ1 and θ2 to ECU 30. ECU 30 can calculate rotational speeds MRN1, MRN2 and angular speeds ω1, ω2 (rad / s) of motor generators MG1, MG2 based on rotational angles θ1, θ2. Note that the rotation angle sensors 26 and 27 may not be arranged by directly calculating the rotation angles θ1 and θ2 from the motor voltage and current in the ECU 30.

  Although not shown, ECU 30 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer, and controls each device of vehicle 100. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  As representative functions, the ECU 30 includes the input torque command values TR1 and TR2, the DC voltage VL detected by the voltage sensor 19, the DC current IB detected by the current sensor 11, and the system voltage detected by the voltage sensor 13. Based on VH, motor currents MCRT1, MCRT2 from current sensors 24, 25, rotation angles θ1, θ2 from rotation angle sensors 26, 27, etc., motor generators MG1, MG2 generate torques according to torque command values TR1, TR2. The operations of the converter 12 and the inverter 23 are controlled so as to output. That is, switching control signals PWC, PWI1, and PWI2 for controlling converter 12 and inverter 23 as described above are generated and output to converter 12 and inverter 23, respectively.

  During the boosting operation of converter 12, ECU 30 feedback-controls system voltage VH to generate switching control signal PWC so that system voltage VH matches the voltage target value.

  Further, when vehicle 100 enters the regenerative braking mode, ECU 30 generates switching control signals PWI1 and PWI2 so as to convert the AC voltage generated by motor generators MG1 and MG2 into a DC voltage, and outputs it to inverter 23. Thus, inverter 23 converts the AC voltage generated by motor generators MG1 and MG2 into a DC voltage and supplies it to converter 12.

  Further, when vehicle 100 enters the regenerative braking mode, ECU 30 generates a switching control signal PWC so as to step down the DC voltage supplied from inverter 23 and outputs it to converter 12. Thus, the AC voltage generated by motor generators MG1 and MG2 is converted into a DC voltage, and is further stepped down and supplied to power storage device 28.

  In the configuration of the converter 12 as described above, when switching the switching states of the switching elements Q1 and Q2, in order to prevent the two switching elements from being simultaneously turned on (conductive state), both the switching elements are temporarily connected. In general, a dead time for turning off is automatically provided. However, due to the influence of this dead time, there is a problem that the output voltage of the converter 12 varies when the direction of the current flowing through the reactor L1 changes.

  In order to solve such a problem, the ECU 30 employs a method of suppressing fluctuations in the output voltage of the converter 12 by feedback controlling the current flowing through the converter 12 (that is, the current IL flowing through the reactor L1). There is a case.

  However, if the current sensor 18 used for detecting the current IL flowing through the reactor L1 is in a state where the detection value is shifted due to a failure or the like, the converter 12 is based on the erroneous current detection value. Therefore, there is a possibility that damage and deterioration of the device may be caused due to excessive current and voltage generated due to this.

  Therefore, in the present embodiment, the presence or absence of abnormality of current sensor 18 is detected by comparing reactor current IL detected by current sensor 18 with battery current IB of power storage device 28 detected by current sensor 11. A method for controlling the converter 12 based on the abnormality detection result will be described. As a result, abnormality detection of the current sensor 18 is performed without adding new components, and damage and deterioration of the device due to the converter 12 being controlled based on an erroneous current detection value are suppressed.

  The difference between reactor current IL and battery current IB will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a diagram showing characteristics of reactor current IL and battery current IB. Referring to FIG. 2, battery current IB detection current sensor 11 is mainly responsible for monitoring the state of charge of power storage device 28, and the sampling period of ECU 30 is, for example, about 10 ms. On the other hand, the current sensor 18 for detecting the reactor current IL mainly plays a role of detecting a feedback current for controlling the current of the converter 12, so that the sampling period by the ECU 30 is, for example, about 100 μs and the battery current IB Shorter than the sampling period.

  FIG. 3 is a diagram showing an example of a temporal change in the current flowing through each current sensor. The reactor current IL increases and decreases every time switching elements Q1 and Q2 perform a switching operation. Are switched, and therefore ripples are included as shown by W1 in FIG. On the other hand, since the ripple component of the reactor current IL is absorbed by the smoothing capacitor C1, the battery current IB becomes a substantially constant DC current as indicated by a broken line W2 in FIG.

  Therefore, when comparing reactor current IL and battery current IB, a smoothing process for removing the ripple component of reactor current IL is required.

  As described with reference to FIG. 1, auxiliary systems such as the air conditioner 50, the DC / DC converter 51, and the auxiliary load 52 are connected to the path connecting the power storage device 28 and the converter 12. Therefore, part of the current output from power storage device 28 flows through these auxiliary systems. Therefore, when the reactor current IL and the battery current IB are compared, it is necessary to consider the current flowing through these auxiliary systems.

  FIG. 4 is a functional block diagram for explaining sensor abnormality detection control executed by the ECU 30 in the present embodiment. Each functional block described in the functional block diagram illustrated in FIG. 4 and FIGS. 12, 14, 15, 17, 19, and 20 described later is realized by hardware or software processing by the ECU 30.

  Referring to FIGS. 1 and 4, ECU 30 includes voltage command generation unit 200, voltage control unit 210, current control unit 220, drive command generation unit 230, sampling hold unit 240, and carrier generation unit 250. , A smoothing unit 270 and a sensor monitoring unit 280.

  Voltage command generation unit 200 receives required torques TR1, TR2 for motor generators MG1, MG2 and rotational speeds MRN1, MRN2 of motor generators MG1, MG2. Based on these pieces of information, voltage command generation unit 200 generates voltage command VREF for the output voltage of converter 12 (ie, the input voltage of inverter 14).

The voltage control unit 210 includes a subtraction unit 211 and a voltage control calculation unit 212.
The subtraction unit 211 calculates a voltage deviation between the voltage command VREF received from the voltage command generation unit 200 and the feedback value VH of the system voltage of the converter 12 detected by the voltage sensor 13, and outputs the calculation result to the voltage control calculation unit 212. Output.

  The voltage control calculation unit 212 calculates the command value ILREF of the reactor current flowing through the reactor L1 by performing PI calculation on the voltage deviation calculated by the subtraction unit 211.

  Thus, voltage control unit 210 calculates reactor current command value ILREF by performing feedback control of system voltage VH of converter 12 (hereinafter also simply referred to as “voltage control”). Voltage control calculation unit 212 outputs reactor current command value ILREF to current control unit 220.

The current control unit 220 includes a subtraction unit 221 and a current control calculation unit 222.
The subtraction unit 221 calculates a current deviation between the reactor current command value ILREF from the voltage control calculation unit 212 and the feedback value of the reactor current IL in which the detection value is held for each sampling period by the sampling hold unit 240, The result is output to the control calculation unit 222.

  The current control calculation unit 222 calculates the duty DUTY, which is the on-period ratio of the switching elements Q1 and Q2, by performing PI calculation on the current deviation calculated by the subtraction unit 221. The feedback control by the current control unit 220 is hereinafter simply referred to as “current control”.

  The voltage control unit 210 and the current control unit 220 form a main loop 205 for making the system voltage VH coincide with the voltage command VREF. Current control unit 220 forms a minor loop for matching reactor current IL to current command IREF.

  As described above, by performing the current feedback control in addition to the voltage feedback control, even when a current deviation occurs due to a dead time or the like, the duty DUTY can be quickly changed accordingly. As a result, the voltage fluctuation of the system voltage VH due to the current deviation can be reduced.

  Drive command generation unit 230 controls on / off of switching elements Q1 and Q2 of converter 12 based on a comparison between duty DUTY from current control calculation unit 222 and carrier wave CR from carrier generation unit 250. A switching control signal PWC that is a PWM (Pulse Width Modulation) signal is generated.

  With this switching control signal PWC, when motor generators MG1, MG2 are in power running, the output voltage from power storage device 28 is boosted to the desired input voltage of inverter 23. When motor generators MG1 and MG2 are regenerative, DC power generated by motor generators MG1 and MG2 and converted by inverter 23 is stepped down to the charging voltage of power storage device 28.

  The carrier generation unit 250 outputs a carrier wave CR having a predetermined carrier frequency to the drive command generation unit 230. Further, the carrier generation unit 250 outputs the sampling signal SMP to the sampling hold unit 240. The sampling hold unit 240 detects and holds the reactor current IL detected by the current sensor 18 when each sampling signal SMP is input. Then, the sampling hold unit 240 outputs the detected current value ILS to the subtraction unit 221 and the smoothing unit 270.

  Smoothing unit 270 receives current value ILS detected by sampling hold unit 240. Then, the smoothing unit 270 smoothes the input current value ILS in the time axis direction. Several methods can be considered for the smoothing process, and an example thereof will be described with reference to FIGS. In the following description, in order to facilitate understanding, a case of a reactor current in a steady state where motor generators MG1 and MG2 are not accelerating or decelerating will be described.

FIG. 5 is a diagram for explaining an example of the smoothing process performed by the smoothing unit 270.
Referring to FIG. 5, reactor current IL detected by current sensor 18 switches between increasing and decreasing each time switching elements Q1 and Q2 are switched. Therefore, a ripple is applied as shown by W10 in FIG. It will be included. Smoothing section 270 samples reactor current IL n times over a predetermined period (for example, N cycles of carrier CR; N is a natural number). Then, the smoothing unit 270 calculates an average value of the sampled n current detection values I1 to In as in Expression (1), and uses the obtained result as a current value ILF after smoothing as a sensor monitoring unit. Output to 280.

ILF = (I1 + I2 +... + In) / n (1)
Further, instead of the average value of the n current detection values I1 to In, smoothing may be performed by a first-order lag filter as shown in FIG.

FIG. 7 is a diagram for explaining another example of the smoothing process performed by the smoothing unit 270.
Referring to FIG. 7, similarly to FIG. 5, reactor current IL detected by current sensor 18 includes a ripple like W <b> 20 in FIG. 7. At this time, the smoothing unit 270 samples the current values ILp and ILn at the timing when the current switches from increase to decrease or from decrease to increase, that is, the timing at which the switching elements Q1 and Q2 are switched. The intermediate value between the current values ILp and ILn sampled in this manner is output to the sensor monitoring unit 280 as the current value ILF after smoothing (W21 in FIG. 7).

ILF = (ILp + ILn) / 2 (2)
FIG. 8 is a diagram for explaining still another example of the smoothing process performed by the smoothing unit 270. In FIG. 8, the vertical axis represents the carrier CR and the reactor current IL.

  Referring to FIG. 8, switching is performed at a time when a carrier wave CR having a predetermined period (W32 in FIG. 8) and duty DUTY (W33 in FIG. 8) which is the on-period ratio of switching elements Q1 and Q2 intersect. The elements Q1 and Q2 are switched. Thereby, the reactor current IL is switched from increasing to decreasing or decreasing to increasing. Smoothing section 270 samples reactor current IL at the time when carrier CR becomes a peak or valley, that is, at a time near the middle of adjacent switching timings of switching elements Q1 and Q2, and smoothes the sampled current value. The subsequent current value ILF (W31 in FIG. 8) is output to the sensor monitoring unit 280.

  Referring to FIG. 4 again, sensor monitoring unit 280 receives battery current IB from current sensor 11 and smoothed reactor current ILF from smoothing unit 270.

  Then, the sensor monitoring unit 280 determines whether the current sensor 18 is abnormal by comparing the battery current IB with the smoothed reactor current ILF. Specifically, when the absolute value of the difference between battery current IB and smoothed reactor current ILF is larger than a predetermined threshold, it is determined that current sensor 18 has an abnormality.

  Then, the sensor monitoring unit 280 sets the abnormality flag FLT of the current sensor 18 and outputs it to the drive command generation unit 230. Specifically, when the current sensor 18 has an abnormality, the abnormality flag FLT is set to ON, and when the current sensor 18 has no abnormality, the abnormality flag FLT is set to OFF.

  When the abnormality flag FLT is off (that is, when there is no abnormality in the current sensor 18), the drive command generation unit 230, as described above, the carrier CR from the carrier generation unit 250 and the duty from the current control calculation unit 222. A switching control signal PWC is generated based on the comparison with DUTY.

  On the other hand, when abnormality flag FLT is on (that is, when abnormality is present in current sensor 18), converter 12 is controlled by switching control signal PWC generated by feedback control of reactor current IL that may be out of reality. If is controlled, the equipment may be damaged or deteriorated. Therefore, the drive command generation unit 230 generates the control signal PWC without using the duty DUTY. For example, the control signal PWC is generated so that the switching element Q1 is fixed on and the switching element Q2 is fixed off.

  In the above description, the case where the vehicle is in a steady state has been described. However, the above averaging method can be applied even when the vehicle is not in a steady state. In actual control of the converter, the carrier period of the carrier wave is, for example, about 0.1 ms (10 kHz at the carrier frequency). On the other hand, the change in the reactor current IL caused by the change in the running state of the vehicle is, for example, about 10 to 100 ms (10 to 100 Hz at the carrier frequency). The change in the reactor current IL due to the change in the running state is very small. For this reason, in a short period such as one cycle (or several cycles) of the carrier wave, the influence of the change in the reactor current IL caused by the change in the running state of the vehicle is small, so it can be considered to be almost the same as in the steady state described above. .

  In the above description, the case where the reactor current IL in the steady state is positive has been described. However, the present invention can be applied to a case where the reactor current IL is negative and a case where the reactor current crosses zero.

  FIG. 9 is a flowchart for explaining details of the sensor abnormality detection control process executed by the ECU 30 in the first embodiment. Each step in the flowchart shown in FIG. 9 and FIGS. 10, 13, 16, 18, and 21, which will be described later, is realized by executing a program stored in the ECU 30 in a predetermined cycle. Alternatively, for some steps, processing can be realized by dedicated hardware (electronic circuit).

  Referring to FIGS. 1 and 9, ECU 30 detects battery current IB by current sensor 11 at step (hereinafter, step is abbreviated as S) 300. Next, the ECU 30 samples the reactor current IL detected by the current sensor 18 in S310, and performs the smoothing process as described above in S320, so that the reactor current value ILF after smoothing is performed. Is calculated.

  Next, in S330, ECU 30 compares reactor current value ILF after smoothing with battery current IB, and determines whether or not the absolute value of these differences is greater than a predetermined threshold value ΔIth.

  Here, this threshold value ΔIth is set in consideration of the current consumed in the above-described auxiliary system. For example, it is also possible to add the current consumption of each predetermined device in accordance with the operation command and the operation state of each device in the auxiliary system, and sequentially set the threshold value ΔIth by adding a margin to the calculation result. . However, since the current consumed by the auxiliary machine is much smaller than the current consumed by the vehicle running (ie, the reactor current), a fixed value obtained by adding a margin to the total maximum current consumed by the auxiliary machine system. Employing the method of setting the threshold value ΔIth is preferable because the calculation load on the ECU 30 can be reduced.

  If the absolute value of the difference between smoothed reactor current value ILF and battery current IB is greater than threshold value ΔIth (YES in S330), the process proceeds to S340. In S340, ECU 300 determines that current sensor 18 has an abnormality, and sets abnormality flag FLT to ON. In S350, ECU 30 generates switching control signal PWC that fixes switching element Q1 on and switches switching element Q2 off, and outputs them to converter 12.

  On the other hand, if the absolute value of the difference between smoothed reactor current value ILF and battery current IB is equal to or smaller than threshold value ΔIth (NO in S330), the process proceeds to S345. In S345, ECU 300 determines that current sensor 18 is normal and sets abnormality flag FLT to OFF. In S355, ECU 30 generates switching control signal PWC based on comparison between carrier CR from carrier generation unit 250 and duty DUTY obtained by feedback control of reactor current IL, and outputs it to converter 12. To do.

  By performing control according to the above-described processing, it is possible to determine whether or not there is an abnormality in the current sensor 18 that detects the reactor current IL without adding a new component. Accordingly, excessive current and voltage generated due to feedback control using an incorrect reactor current can be suppressed, so that damage and deterioration of the device can be prevented.

[Modification of Embodiment 1]
In the first embodiment, when the absolute value of the difference between smoothed reactor current value ILF and battery current IB is larger than threshold value ΔIth, it is determined that current sensor 18 is abnormal. However, for example, when the rotational speed of the drive wheel 42 of the vehicle temporarily changes suddenly due to slipping or gripping, or when the detection value of the reactor current IL is affected by temporary external noise or the like, such transients occur. If the control of the converter 12 is changed immediately in response to a change in the characteristics, the control efficiency and drivability may be deteriorated.

  Therefore, in the modification of the first embodiment, the current sensor is abnormal when the absolute value of the difference between the smoothed reactor current value ILF and the battery current IB is greater than the threshold value ΔIth for a predetermined period. Is determined. By doing in this way, the influence by the above transient changes can be reduced.

  FIG. 10 is a flowchart for explaining details of the sensor abnormality detection control process executed by the ECU 30 in the modification of the first embodiment. In FIG. 10, steps S331 and S332 are added to the flowchart of FIG. 9 of the first embodiment. In FIG. 10, the description of the same steps as those in FIG. 9 will not be repeated.

  Referring to FIGS. 1 and 10, if the absolute value of the difference between smoothed reactor current value ILF and battery current IB is larger than threshold value ΔIth (YES in S330), the process proceeds to S331. It is done. Then, the ECU 30 counts up a timer in S331.

  Next, ECU 30 determines in S332 whether or not the timer count is greater than a predetermined threshold value Tth, so that the absolute value of the difference between smoothed reactor current value ILF and battery current IB is a threshold value. It is determined whether or not a state larger than ΔIth continues for a predetermined period.

  If the timer count is equal to or smaller than predetermined threshold value Tth (NO in S332), the process proceeds to S345. In this case, the ECU 30 determines that the current sensor 18 is normal, assuming that there is a high possibility of an influence due to the transient change, and continues normal operation in S355.

  On the other hand, if the timer count is greater than predetermined threshold value Tth (NO in S332), the process proceeds to S340, and ECU 30 determines that current sensor 18 is abnormal. Then, in S350, a switching control signal PWC that fixes switching element Q1 on and fixes switching element Q2 off is generated and output to converter 12.

  By controlling according to the processing as described above, it is possible to determine whether or not there is an abnormality in the current sensor 18 that detects the reactor current IL without adding a new component while reducing the influence due to the transient change. it can.

[Variation of countermeasures for current sensor abnormality]
In the first embodiment, the method of fixing the upper arm switching element Q1 on the converter 12 and fixing the lower arm switching element Q2 off when the current sensor 18 becomes abnormal has been described. In this case, since the boosting operation of the converter 12 is substantially stopped, the system voltage VH is lowered to the voltage VL of the smoothing capacitor C1. Then, there is a risk that the driving performance of the vehicle may be restricted, such as the maximum driving torque that can be output from the inverter 23 is reduced.

  Therefore, in the second to fifth embodiments described below, even if the current sensor 18 is abnormal, the boost operation by the converter 12 is executed as much as possible to reduce the influence on the running performance of the vehicle. The structure to perform is demonstrated.

[Embodiment 2]
In the control of the converter 12, the purpose of using the current sensor 18 for detecting the reactor current IL flowing through the reactor L1 is that current feedback control, as described with reference to FIG. It was to reduce the voltage fluctuation of the system voltage VH due to the deviation.

  However, even if a voltage boosting operation is performed in which only the voltage feedback control is performed without performing the current feedback control, the voltage fluctuation of the system voltage VH due to the current deviation cannot be reduced, but the system voltage VH is made higher than the voltage VL. Therefore, compared with the case where the switching element Q1 of the upper arm is fixed on, the influence on the running performance such as the reduction of the maximum driving torque can be reduced.

  Therefore, in the second embodiment, when abnormality of the current sensor 18 is detected, the current feedback control using the current detection value by the current sensor 18 is stopped and the switching control for switching to the converter control by the voltage feedback control is performed. .

  FIG. 11 is a diagram for explaining a state of system voltage VH due to a difference in control of converter 12. In FIG. 11, (1) when only voltage control is performed, (2) when both voltage control and current control are always performed, and (3) when the upper arm is fixed on when the current sensor is abnormal (in the first embodiment) Correspondence), and (4) When switching to voltage control when the current sensor is abnormal (corresponding to the second embodiment), an example of the state of the system voltage VH when the reactor current sensor is normal and abnormal is shown.

  Referring to FIG. 11, when only voltage control is performed, current feedback control using the detection value of current sensor 18 is not performed. Therefore, whether current sensor 18 is normal or abnormal, The state of the system voltage VH does not change. In this case, since the step-up operation is performed, the system voltage VH is higher than the voltage VL of the smoothing capacitor C1, but voltage fluctuation occurs because the current feedback control is not performed.

  Next, when both voltage control and current control are always performed, when current sensor 18 is normal, voltage fluctuation is reduced by current feedback control, so system voltage VH is stable near the target voltage. However, when the current sensor 18 is abnormal, the current feedback control cannot be performed, so that the converter 12 cannot be controlled.

  In the case where the upper arm is fixed on when the current sensor 18 described in the first embodiment is abnormal, the voltage fluctuation is reduced by the current feedback control when the current sensor 18 is normal, but when the current sensor 18 is abnormal, Since the boosting operation by the converter 12 is stopped, the system voltage VH decreases to near the voltage VL.

  When the switching control of the second embodiment is applied, the voltage fluctuation is reduced by the current feedback control when the current sensor 18 is normal, and the voltage fluctuation occurs when the current sensor 18 is abnormal, but the system voltage VH is A state higher than the voltage VL is maintained. Therefore, even when the current sensor 18 is abnormal, the boosting operation is performed, so that the running performance of the vehicle can be maintained to some extent.

  FIG. 12 is a functional block diagram for illustrating the switching control executed by the ECU 30 in the second embodiment. FIG. 12 is obtained by adding a switching unit 260 to the functional block diagram of FIG. 4 of the first embodiment. In FIG. 12, the description of the functional blocks overlapping those in FIG. 4 will not be repeated.

Referring to FIG. 12, ECU 30 further includes a switching unit 260.
Switching unit 260 receives the control output of voltage control unit 210, the control output of current control unit 220, and the abnormality flag FLT of current sensor 18 from sensor monitoring unit 280.

  Based on the abnormality flag FLT of the current sensor 18 from the sensor monitoring unit 280, the switching unit 260 outputs a control output from the current control unit 220 when the current sensor 18 is normal (that is, when the abnormality flag FLT is off). It switches so that it may select, and outputs the result to the drive command production | generation part 230 as duty DUTY.

  On the other hand, when the current sensor 18 is abnormal (that is, when the abnormality flag FLT is on), the switching unit 260 switches so as to select the control output from the voltage control unit 210, and the result is the drive command generation unit 230. Is output as a duty DUTY.

  Drive command generation unit 230 generates control signal PWC for controlling converter 12 based on the comparison between duty DUTY received from switching unit 260 and carrier wave CR from carrier generation unit 250, and controls to converter 12 The signal PWC is output.

  FIG. 13 is a flowchart for illustrating details of the switching control process executed by ECU 30 in the second embodiment. FIG. 13 is obtained by replacing step S350 in the flowchart of FIG. 9 of the first embodiment with S350A. In FIG. 13, the description of the same steps as those in FIG. 9 will not be repeated.

  Referring to FIG. 13, when the absolute value of the difference between smoothed reactor current ILF and battery current IB is equal to or smaller than a predetermined threshold value ΔIth (NO in S330), ECU 30 indicates that current sensor 18 is normal. Is determined (S345), and the converter 12 is controlled by current feedback control using the detected reactor current value detected by the current sensor 18 (S355).

  On the other hand, if the absolute value of the difference between smoothed reactor current ILF and battery current IB is greater than a predetermined threshold value ΔIth (YES in S330), ECU 30 determines that current sensor 18 is abnormal. (S340), the process proceeds to S350A.

  In S350A, ECU 30 selects the control output from voltage control unit 210 in switching unit 260 of FIG. 12, thereby stopping current feedback control and controlling converter 12 by voltage feedback control.

  By performing the control according to the above processing, even when the reactor current sensor becomes abnormal, the converter 12 can perform the boosting operation, so that the influence on the running performance of the vehicle can be reduced.

[Modification of Embodiment 2]
In the second embodiment, the configuration in which the control output of the voltage control calculation unit 212 of the voltage control unit 210 is duty-duty when the current sensor 18 is abnormal has been described.

  However, internal variables such as a control gain in the voltage control calculation unit 212 are adjusted based on the assumption that current feedback control is originally performed. Therefore, if the control output of the voltage control calculation unit 212 is used as it is as the duty DUTY in the drive command generation unit 230, the control of the converter 12 becomes unstable such that the system voltage VH oscillates and the control is lost. There is a possibility.

  Therefore, in a modification of the second embodiment, a configuration that further includes another voltage control unit that is separate from voltage control unit 210 will be described.

  FIG. 14 is a functional block diagram for explaining switching control executed by ECU 30 in the modification of the second embodiment. FIG. 14 is obtained by adding a voltage control unit 210A to the functional block diagram of FIG. 12 of the second embodiment. In FIG. 14, the description of the functional blocks overlapping those in FIGS. 4 and 12 will not be repeated.

Referring to FIG. 14, ECU 30 further includes a voltage control unit 210A.
Voltage control unit 210A includes subtraction unit 211A and voltage control calculation unit 212A. The voltage control unit 210A has the same configuration as the voltage control unit 210. That is, the subtraction unit 211A calculates a voltage deviation between the voltage command VREF and the feedback value VH of the system voltage, and the voltage control calculation unit 212A performs a PI calculation on the voltage deviation calculated by the subtraction unit 211A. The duty DUTY2 of Q1 and Q2 is calculated.

  Based on abnormality flag FLT from sensor monitoring unit 280, switching unit 260 switches between duty DUTY1 received from current control unit 220 and duty DUTY2 received from voltage control unit 210A. Specifically, switching unit 260 switches to select duty DUTY1 when abnormality flag FLT is off (ie, there is no abnormality in current sensor 18), and abnormality flag FLT is on (ie, abnormality is detected in current sensor 18). Switch to select duty DUTY2. Then, the selection result is output to the drive command generation unit 230 as the duty DUTY.

  With such a configuration, when only voltage feedback control is performed, the control gain of the voltage control unit or the like can be adjusted in advance to a value suitable for performing only voltage feedback control. Therefore, converter 12 can be stably controlled even when only the voltage control is switched when current sensor 18 is abnormal.

[Embodiment 3]
In the modification of the second embodiment, a configuration is described in which, when the current sensor 18 is abnormal, it is possible to set a control gain or the like suitable for performing only voltage control by switching to another voltage control unit. did.

  In the third embodiment, as in the second embodiment, in the configuration in which one voltage control unit is provided and switching control between current control and voltage control is performed, when the current sensor 18 is abnormal, the voltage control calculation unit In addition to switching so that the control output of 212 is set as the duty DUTY, a configuration for changing the control gain of the voltage control calculation unit 212 to a value suitable for voltage control will be described. By adopting such a configuration, converter 12 can be stably controlled even when only voltage control is executed without providing separate voltage control unit 210A as in the modification of the second embodiment. Can do.

  FIG. 15 is a functional block diagram for illustrating gain change control executed by the ECU 30 in the third embodiment. FIG. 15 is a functional block diagram of FIG. 12 according to the second embodiment, in which the abnormality flag FLT from the sensor monitoring unit 280 is output to the voltage control calculation unit 212 in addition to the switching unit 260. In FIG. 15, the description of the functional blocks overlapping those in FIGS. 4 and 12 will not be repeated.

  Referring to FIG. 15, voltage control calculation unit 212 has a voltage deviation between voltage command VREF calculated by subtraction unit 211 and feedback value VH of the system voltage, and abnormality flag FLT of current sensor 18 from sensor monitoring unit 280. Receive.

  The voltage control calculation unit 212 has control variables (for example, control gain) suitable for each control when performing both voltage control and current control and when performing only voltage control. Then, the voltage control calculation unit 212 sets this control variable in accordance with the abnormality flag FLT of the current sensor 18, and performs a PI calculation on the voltage deviation from the subtraction unit 211 using the set control variable to thereby control the current control. To unit 220 and switching unit 260.

  FIG. 16 is a flowchart for illustrating the details of the gain change control process executed by ECU 30 in the third embodiment. FIG. 16 is obtained by adding steps S341 and S346 to the flowchart of FIG. 13 of the second embodiment. In FIG. 16, the description of the same steps as those in FIGS. 9 and 13 will not be repeated.

  Referring to FIG. 16, when the absolute value of the difference between smoothed reactor current ILF and battery current IB is equal to or smaller than a predetermined threshold value ΔIth (NO in S330), ECU 30 determines that current sensor 18 is normal. A determination is made (S345), and the process proceeds to S346.

  In S346, ECU 30 sets the control gain used for voltage control to a value suitable for performing both voltage control and current control. Then, ECU 30 controls converter 12 by current feedback control using the reactor current detection value detected by current sensor 18 (S355).

  On the other hand, if the absolute value of the difference between smoothed reactor current ILF and battery current IB is greater than a predetermined threshold value ΔIth (YES in S330), ECU 30 determines that current sensor 18 is abnormal. (S340), the process proceeds to S341.

  In S341, the ECU 30 sets a control gain used for voltage control to a value suitable for performing only voltage control. Specifically, the control gain is set to a lower value than when both voltage control and current control are performed. The control gain includes a proportional gain and an integral gain in PI calculation.

  In S350A, ECU 30 switches the control output from voltage control calculation unit 212 of FIG. 15 to duty DUTY, stops current feedback control, and controls converter 12 by voltage feedback control.

  By controlling according to the above processing, even when the reactor current sensor becomes abnormal, converter 12 can be stably controlled only by voltage control without additionally providing a separate voltage control unit.

[Embodiment 4]
In the second embodiment and the third embodiment, the configuration for switching between the current control and the voltage control has been described. However, when only the voltage control is executed as described with reference to FIG. appear. In particular, as in the modification of the third embodiment or the second embodiment, in order to ensure the control stability of the converter 12, when setting a control gain lower than that in the case of performing current control, the voltage fluctuation The fluctuation range may increase.

  In addition, when both voltage control and current control are performed, the voltage fluctuation of the system voltage VH can be reduced. Therefore, in order to reduce the component cost, the capacitor capacity in the circuit and the withstand voltage of each component can be reduced. It may be performed together.

  Then, it is conceivable that if the voltage fluctuation of the system voltage VH is increased by performing only the voltage control when the current sensor fails, the allowable value of the withstand voltage of each component is exceeded.

  Therefore, in the fourth embodiment, when switching control is performed so that only voltage control is performed when the current sensor is abnormal, voltage command change control is performed to reduce the upper limit value of the variable range of voltage command VREF. Thus, it is possible to prevent the voltage fluctuation range of the system voltage VH generated when only voltage control is performed from exceeding the allowable value of the withstand voltage of each component.

  FIG. 17 is a functional block diagram for explaining voltage command change control executed by the ECU 30 in the fourth embodiment. FIG. 17 is a block diagram in which the voltage control unit 210 is replaced with a voltage control unit 210B to which a command limiting unit 213 is added in the functional block diagram of FIG. 12 of the second embodiment. In this case, the main loop 205B is formed by the voltage control unit 210B and the current control unit 220. In FIG. 17, the description of the functional blocks overlapping those in FIGS. 4 and 12 will not be repeated.

  Referring to FIG. 17, command restriction unit 213 receives voltage command VREF generated by voltage command generation unit 200 and abnormality flag FLT of current sensor 18 from sensor monitoring unit 280. In command limiter 213, the upper limit value of the variable range of voltage command VREF is set. When the voltage command VREF exceeds the upper limit value, the command limiter 213 sets the upper limit value as a voltage command used for voltage feedback control and outputs the voltage command to the subtractor 211.

  Further, the command limiter 213 changes the setting of the upper limit value of the voltage command VREF according to the abnormality flag FLT from the sensor monitoring unit 280. Specifically, when the abnormality of the current sensor 18 is detected and the abnormality flag FLT is set to ON, the command limiter 213 sets the upper limit value of the voltage command VREF more than when the current sensor 18 is normal. Set to decrease.

  With such a configuration, even when abnormality of the current sensor 18 is detected and only voltage control is performed, the voltage fluctuation range of the system voltage VH can be reduced. It is possible to prevent the withstand voltage value of the component from being exceeded.

  FIG. 18 is a flowchart for illustrating details of a voltage command change control process executed by ECU 30 in the fourth embodiment. FIG. 18 is obtained by adding steps S342 and S347 to the functional block diagram of FIG. 13 of the second embodiment. In FIG. 18, the description of the functional blocks overlapping those in FIGS. 9 and 13 will not be repeated.

  Referring to FIG. 18, when ECU 30 determines that current sensor 18 is normal (S345), ECU 30 advances the process to S347 to perform both voltage control and current control on the upper limit value of the variable range of voltage command VREF. Set to a value (normal value) suitable for. Then, ECU 30 controls converter 12 by current feedback control using the reactor current detection value detected by current sensor 18 (S355).

  On the other hand, when the ECU 30 determines that the current sensor 18 is abnormal (S340), the ECU 30 advances the process to S342, and sets the upper limit value of the variable range of the voltage command VREF to a value lower than the normal value.

  In S350A, ECU 30 switches the control output from voltage control calculation unit 212 of FIG. 17 to duty DUTY, stops current feedback control, and controls converter 12 by voltage feedback control.

  By controlling according to the above processing, even when the reactor current sensor 18 becomes abnormal, the system voltage VH exceeds the allowable voltage tolerance of each component while stably controlling the converter 12 only by voltage control. Can be prevented.

  Note that the fourth embodiment can also be applied to the gain change control of the third embodiment. FIG. 19 is a functional block diagram when the fourth embodiment is applied to the third embodiment. In FIG. 19, in the functional block diagram of FIG. 15 of the third embodiment, the voltage control unit 210 is replaced with a voltage control unit 210B to which a command limiting unit 213 is added. The description of each functional block will not be repeated, but with such a configuration, when the current sensor 18 becomes abnormal, the setting of the control gain can be reduced in the voltage control calculation unit 212 and the command limiting unit 213 The upper limit value of the voltage command VREF can be lowered. As a result, even when the reactor current sensor becomes abnormal, it is possible to prevent the system voltage VH from exceeding the allowable withstand voltage value of each component while stably controlling the converter 12 only by voltage control.

[Embodiment 5]
In the second embodiment, the configuration in which the current control is stopped and only the voltage control is performed when the reactor current sensor 18 becomes abnormal has been described. However, as described above, it is desirable to perform current control as much as possible in order to reduce the voltage fluctuation of the system voltage VH.

Therefore, in the fifth embodiment, when the reactor current sensor 18 becomes abnormal, sensor selection control that performs feedback control using the battery current IB detected by the battery current sensor 11 instead of the reactor current IL. Since the average value of the current detected by the reactor current sensor 18 to be explained is basically the current input / output to / from the power storage device 28 minus the current consumed by the auxiliary system, the reactor current IL and It does not necessarily match the battery current IB. However, as described above, the current consumed by the auxiliary system is much smaller than the current consumed by the vehicle traveling, so even if feedback control is performed using the battery current IB instead of the reactor current IL, It can be expected to suppress the voltage fluctuation of the system voltage VH. As the battery current used for feedback control, for example, a value obtained by subtracting a fixed value in consideration of the current consumed by the auxiliary system from the detection value detected by the battery current sensor 11 may be used.

  FIG. 20 is a functional block diagram for illustrating sensor selection control executed by the ECU 30 in the fifth embodiment. FIG. 20 is obtained by adding a sensor selection unit 245 to the functional block diagram of FIG. 4 of the first embodiment. In FIG. 20, the description of the functional blocks overlapping those in FIG. 4 will not be repeated.

  Referring to FIG. 20, sensor selection unit 245 includes a detection value of reactor current IL detected by reactor current sensor 18, a detection value of battery current IB detected by battery current sensor 11, and sensor monitoring unit 280. An abnormal flag FLT is received.

  The sensor selection unit 245 is configured to be able to select either the reactor current IL or the battery current IB, and switches the selection of the reactor current IL and the battery current IB according to the abnormality flag FLT from the sensor monitoring unit 280. . Specifically, sensor selection unit 245 selects reactor current IL when abnormality flag FLT is off (ie, reactor current sensor 18 is normal), while abnormality flag FLT is on (ie, reactor current sensor 18). Is abnormal), the battery current IB is selected.

  Then, the sensor selection unit 245 outputs the selected current detection value to the sampling hold unit 240. Thereby, when reactor current sensor 18 is abnormal, current feedback control is performed using battery current IB.

  FIG. 21 is a flowchart for explaining details of the sensor selection control process executed by the ECU 30 in the fifth embodiment. FIG. 21 is obtained by replacing step S350 with S350B in the functional block diagram of FIG. 9 of the first embodiment. In FIG. 21, the description of the functional blocks overlapping those in FIG. 9 will not be repeated.

  Referring to FIG. 21, when ECU 30 determines that reactor current sensor 18 is normal (S345), ECU 30 controls converter 12 by current feedback control using reactor current detection value IL detected by reactor current sensor 18 (S355). ).

  On the other hand, when ECU 30 determines that reactor current sensor 18 is abnormal (S340), the process proceeds to S350B.

  Then, in S350B, ECU 30 changes the detected current value used for current feedback control to battery current IB by sensor selection unit 245 of FIG. Then, ECU 30 controls converter 12 by current feedback control using battery current IB.

  By performing the control according to the above processing, when the reactor current sensor 18 becomes abnormal, current control can be performed using the battery current IB detected by the battery current sensor 11. Thereby, even when the reactor current sensor 18 becomes abnormal, it is possible to suppress the voltage fluctuation of the system voltage VH and reduce the influence on the running performance of the vehicle.

  Also in the fifth embodiment, the gain change control described in the third embodiment and the voltage command change control described in the fourth embodiment can be applied. As a result, fluctuations in system voltage VH that can be caused by the difference between the detected value of reactor current IL and the detected value of battery current IB can be further reduced.

  The modification of the first embodiment can also be applied to the second to fifth embodiments and their modifications. That is, it is determined that the current sensor 18 is abnormal when the absolute value of the difference between the reactor current detection value ILF after the averaging process and the battery IB is larger than the predetermined threshold value ΔIth for a predetermined period. You may make it do.

  The switching elements Q1 and Q2 in the present embodiment are examples of the “first switching element” and the “second switching element” in the present invention, respectively. Further, the current sensor 11 and the current sensor 18 in the present embodiment are examples of the “first current sensor” and the “second current sensor” of the present invention, respectively.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 13, 19 Voltage sensor, 11, 18, 24, 25 Current sensor, 12 Converter, 14, 22, 23 Inverter, 15 U-phase arm, 16 V-phase arm, 17 W-phase arm, 20 Power supply system, 26, 27 Rotational angle sensor, 28 Power storage device, 30 ECU, 40 Engine, 41 Power split mechanism, 42 Drive wheel, 45 Load device, 50 Air conditioner, 51 DC / DC converter, 52 Auxiliary load, 53 Auxiliary battery, 100 Vehicle, 200 Voltage command generator, 205, 205B main loop, 210, 210A, 210B Voltage controller, 211, 211A, 221 Subtractor, 212, 212A Voltage control calculator, 213 Command limiter, 220 Current controller, 222 Current control Calculation unit, 230 drive command generation unit, 240 sampling hold unit, 45 sensor selection unit, 250 carrier generation unit, 260 switching unit, 270 smoothing unit, 280 sensor monitoring unit, C1, C2 smoothing capacitor, D1-D8 diode, L1 reactor, MG1, MG2 motor generator, NL ground wire, PL1, PL2 power line, Q1-Q8 switching element, SR1, SR2 system relay.

Claims (11)

A control device of a power supply system for supplying power to a load device,
The power supply system includes:
A rechargeable power storage device;
A first current sensor for detecting a current input to and output from the power storage device;
A voltage converter capable of voltage conversion between the power storage device and the load device, and a converter having a reactor;
A second current sensor for detecting a current flowing through the reactor,
The controller is
A voltage controller configured to adjust the voltage on the load device side of the converter to a target voltage by feeding back the voltage on the load device side of the converter;
A current control unit configured to adjust a current flowing through the reactor to a target current by feeding back a detection value of the second current sensor based on a control output of the voltage control unit;
A drive command generation unit configured to generate a drive command for the converter based on a control output of the current control unit;
An abnormality of the second current sensor is detected based on a comparison between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor. A control device for a power supply system comprising a sensor monitoring unit.   The sensor monitoring unit has an absolute value of a difference between a current detection value detected by the first current sensor and a current detection value detected by the second current sensor larger than a predetermined threshold value. The power supply system control device according to claim 1, wherein the second current sensor is determined to be abnormal when an event is detected.   The sensor monitoring unit is in a state where an absolute value of a difference between a current detection value detected by the first current sensor and a current detection value detected by the second current sensor is larger than the threshold value. The control device for a power supply system according to claim 2, wherein the second current sensor is determined to be abnormal when the current continues for a predetermined period. A smoothing unit configured to smooth the current detection value detected by the second current sensor in the time axis direction;
The power supply according to claim 1, wherein the sensor monitoring unit compares the detection value of the second current sensor smoothed by the smoothing unit with the current detection value detected by the first current sensor. System control unit.   2. The power supply system according to claim 1, wherein when the abnormality of the second current sensor is detected, the control device controls the converter without using a current detection value detected by the second current sensor. Control device. The converter is
A first switching element and a second switching element connected in series between a power line and a ground line of the load device;
A first rectifier element and a second rectifier element connected in parallel to the first switching element and the second switching element, respectively, with a direction from the ground line toward the power line as a forward direction; ,
The reactor is inserted in a path connecting a connection node of the first switching element and the second switching element and a positive electrode terminal of the power storage device,
When the abnormality of the second current sensor is detected, the drive command generation unit fixes the first switching element in an on state and fixes the second switching element in an off state. The power supply system control device according to claim 5, wherein the drive command is generated.   The drive command generation unit generates the drive command based on the control output of the voltage control unit instead of the control output of the current control unit, when an abnormality of the second current sensor is detected, The power supply system control device according to claim 5.   When an abnormality of the second current sensor is detected, the current control unit performs feedback control using the detection value of the first current sensor instead of the detection value of the second current sensor. The control device for the power supply system according to claim 5.   The control device for a power supply system according to claim 7 or 8, wherein the voltage control unit reduces a control gain used for feedback control when an abnormality of the second current sensor is detected.   9. The control device for a power supply system according to claim 7, wherein the voltage control unit decreases an upper limit value for limiting the target voltage when an abnormality of the second current sensor is detected. A rechargeable power storage device;
A first current sensor for detecting a current input to and output from the power storage device;
A driving force generator configured to generate a driving force using electric power from the power storage device;
A converter configured to be capable of voltage conversion between the power storage device and the driving force generator, and a converter including a reactor;
A second current sensor for detecting a current flowing through the reactor;
A control device for controlling the converter,
The controller is
A voltage controller configured to adjust the voltage on the driving force generation unit side of the converter to a target voltage by feeding back the voltage on the driving force generation unit side of the converter;
A current control unit configured to adjust a current flowing through the reactor to a target current by feeding back a detection value of the second current sensor based on a control output of the voltage control unit;
A drive command generation unit configured to generate a drive command for the converter based on a control output of the current control unit;
An abnormality of the second current sensor is detected based on a comparison between the current detection value detected by the first current sensor and the current detection value detected by the second current sensor. A vehicle including a sensor monitoring unit.

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