JP2013112098A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle in which, when a measurement value of a voltage sensor measuring an output voltage of a battery indicates an abnormal value, after shifting to batteryless traveling, it is checked whether the voltage sensor is defective or not and if the voltage sensor is defective, batteryless traveling is returned to normal traveling.SOLUTION: A controller 9 of a hybrid vehicle 100 executes following processing. If a measurement value of a low voltage side voltage sensor 4 is below a threshold voltage, an EV mode is restricted and a first inverter 7 is controlled so as to balance revenue and expenditure between power generated by a first motor 8 and power consumption of electric devices including a second motor 18. A low voltage side and a high voltage side of a converter 5 are short-circuited and if a measurement value of the low voltage side voltage sensor 4 is matched with that of a high voltage side voltage sensor 6, EV mode restriction is maintained. If the measurement value of the low voltage side voltage sensor 4 is lower than that of the high voltage side voltage sensor 6 although the low voltage side and the high voltage side of the converter 5 are short-circuited, EV mode restriction is canceled.

Description

  The present invention relates to a hybrid vehicle including a wheel driving motor and an engine.

  A hybrid vehicle including a wheel driving motor and an engine travels while switching between an EV mode that travels using only the motor without using the engine and an HV mode that travels using both the engine and the motor. The engine is used not only as a driving power source but also as a power source when the motor is used as a generator. Since the hybrid vehicle can charge the battery with the electric power generated by the motor, the capacity of the mounted battery is smaller than that of a pure electric vehicle without an engine. That is, the hybrid vehicle cannot run so long in the EV mode alone.

  Therefore, two motors are provided, and when a battery malfunction (including malfunctions in parts around the battery, such as disconnection of the power supply line for extracting battery power), one motor uses the driving force of the engine. Patent Document 1 and Patent Document 2 propose a technique for generating power, driving the other motor with the electric power, and traveling without depending on the battery.

  In the following, running without relying on the battery as described above is expressed as battery-less running. In addition, driving by driving a motor using a battery is expressed as “normal driving” as an expression for “battery-less driving”. In addition, for the sake of simplicity, supplying power to the motor to obtain the driving force of the wheels is expressed as “powering”, and generating electricity with the motor using the kinetic energy of the vehicle is expressed as “regeneration”. .

JP 2007-196733 A JP 2010-162996 A

  A battery failure is typically determined based on a measurement value of a voltage sensor that measures the output voltage of the battery. Specifically, when the measured value of the voltage sensor falls below a predetermined threshold voltage, it is determined that a problem has occurred in the battery, and the normal traveling is shifted to the batteryless traveling. However, the battery itself is not defective and the voltage sensor may be broken. In that case, it is preferable to run normally instead of batteryless running. This specification is based on the measurement value of the voltage sensor that measures the output voltage of the battery. After the transition to battery-less running, the voltage sensor itself is checked to see if it has failed. Provided is a hybrid vehicle that returns from batteryless running to normal running when there is a high probability.

  Some hybrid vehicles include a converter (DCDC converter) that boosts the output voltage of a battery and supplies the boosted voltage to an inverter. In that case, in addition to the low-voltage side voltage sensor that measures the voltage between the low-voltage side terminals of the converter (corresponding to the voltage sensor that measures the output voltage of the battery), the high-voltage side voltage that measures the voltage between the high-voltage side terminals of the converter A sensor is provided. This specification uses these two voltage sensors to determine whether or not the low-voltage side voltage sensor is normal. As a result, when there is a high probability that the voltage sensor has failed, the batteryless running is returned to the normal running. Note that the voltage measured by the high voltage side voltage sensor corresponds to the voltage between the DC side terminals of the inverter. The voltage between the DC side terminals of the inverter corresponds to the input voltage to the inverter during power running, and corresponds to the DC output voltage of the inverter during regeneration.

  An embodiment of the technology disclosed in this specification will be described. The technology disclosed in this specification is intended for a hybrid vehicle that can switch between an EV mode that travels using only a motor without using an engine and an HV mode that travels using the engine and motor. The hybrid vehicle includes a battery that stores electric power for driving the motor, first and second motors, first and second inverters, a converter, and a controller. The converter boosts the output voltage of the battery and supplies it to the first and second inverters. The converter also has a function of stepping down the voltage of the DC power output from the first inverter to a voltage suitable for battery charging during regeneration. The first motor is used both for outputting a driving force for driving the wheels and for generating electric power by the driving force of the engine or the deceleration energy of the vehicle. The second motor outputs a driving force for driving the wheels. Of course, the second motor may also be used as a generator. The first inverter converts the output power of the converter into alternating current when the driving power is output to the first motor and supplies the alternating current to the first motor. When the first motor generates power, the first inverter generates alternating current. The electric power is converted into direct current and supplied to the battery via the converter and / or supplied to the electric device including the second motor. A 2nd inverter converts the output electric power of a converter into alternating current, and supplies it to a 2nd motor. As described above, the hybrid vehicle disclosed in the present specification further includes a low voltage side voltage sensor that measures a voltage between the low voltage side terminals of the converter and a high voltage side voltage sensor that measures a voltage between the high voltage side terminals of the converter. . The low voltage side voltage sensor corresponds to a voltage sensor that measures the voltage of the battery.

The controller executes the following processing.
(1) When the measured value of the low-voltage side voltage sensor falls below a predetermined threshold voltage, the EV mode is prohibited, and the first motor is rotated by the driving force of the engine, The process which controls a 1st inverter so that the electric power balance with the power consumption of the electric device containing 2 motors may be balanced. Note that prohibiting the EV mode corresponds to keeping the engine driven.
(2) A process of maintaining the EV mode inhibition when the low-voltage side terminal and the high-voltage side terminal of the converter are short-circuited and the measured value of the low-voltage side voltage sensor matches the measured value of the high-voltage side voltage sensor.
(3) Processing for canceling the EV mode prohibition when the measured value of the low-voltage side voltage sensor is lower than the measured value of the high-voltage side voltage sensor despite the short circuit between the low-voltage side terminal and the high-voltage side terminal of the converter.

  The process (1) corresponds to battery-less travel. The processes (2) and (3) correspond to the process of checking whether or not the low-voltage side voltage sensor (that is, the voltage sensor that measures the output voltage of the battery) has failed. The process (2) is a process for maintaining battery-less travel when it is determined that the low-voltage side voltage sensor is normal. The process (3) corresponds to a process of returning from the batteryless travel to the normal travel on the assumption that there is a high probability that the low voltage side voltage sensor has failed.

  The technology disclosed in this specification short-circuits the low-voltage side terminal and the high-voltage side terminal of the converter, and if the values of the low-voltage side voltage sensor and the high-voltage side voltage sensor match, it is determined that both voltage sensors are normal. In this case, it is determined that the low-voltage side voltage sensor that has detected a decrease in the battery voltage output has failed. When it is determined that the low-voltage side voltage sensor has failed, the batteryless traveling is returned to the normal traveling. This is based on the knowledge that the probability of failure of two locations at the same time is extremely low, and that if the voltage sensor is faulty, there is a high probability that the battery is not faulty.

  When the controller determines whether the measured value of the low-voltage side voltage sensor matches the measured value of the high-voltage side voltage sensor, naturally, the difference between the measured values of the two voltage sensors is the sum of the errors of both sensors. If it is within the range of about the value, it may be determined as “match”. In order to improve the certainty of judgment, the controller is programmed to judge “match” if the difference between the measured values of both voltage sensors is within the range of the error plus the specified margin. May be.

  A typical example of a gear train of a hybrid vehicle is a planetary gear having the following connection relationship. That is, the sun gear is connected to the output shaft of the first motor. A planetary carrier is connected to the output shaft of the engine. A ring gear is connected to the output shaft of the second motor. The ring gear (the output shaft of the second motor) is also connected to the axle.

  A typical example of a converter is composed of two switching circuits and a reactor. Specifically, the two switching circuits are connected in series between the high-voltage side terminals of the converter. One end of the reactor is connected to the positive terminal on the low voltage side, and the other end is connected to the midpoint of the two switching circuits. A typical switching circuit is a circuit in which a switching transistor such as an IGBT and a diode are connected in antiparallel. In the case of having such a converter, the controller of the hybrid vehicle can short-circuit the low-voltage side terminal and the high-voltage side terminal by closing the switching circuit between the high-voltage side positive electrode terminal of the converter and the reactor. A switching circuit between the positive terminal on the high voltage side of the converter and the reactor may be called an upper arm.

  The technology disclosed in this specification is a hybrid that can return to normal driving and stably run when there is a high probability that the voltage sensor that measures the output voltage of the battery has failed after shifting to battery-less driving. Provide a car.

It is a typical block diagram of the hybrid vehicle of an Example. It is a skeleton figure of a power distribution mechanism. It is a circuit diagram of a converter. It is a flowchart figure of the process which a controller performs.

  In FIG. 1, the typical block diagram of the hybrid vehicle 100 of an Example is shown. The hybrid vehicle 100 includes a wheel driving engine 21 and two motors (a first motor 8 and a second motor 18). The hybrid vehicle 100 includes a first inverter 7 and a second inverter 17 for each of the first motor 8 and the second motor 18. Both inverters are supplied with electric power from the battery (main battery 2). Both inverters are of the PWM drive type, and the controller 9 supplies the PWM signal. The controller 9 calculates the driving force that the wheel 25 should output from the vehicle speed, the accelerator opening, the remaining amount of the main battery 2 (SOC: State Of Charge), etc., and outputs the motor and engine to obtain the driving force. Calculate the share. Furthermore, the controller 9 gives a PWM signal corresponding to the output sharing to the motor, and commands the engine to a fuel injection amount corresponding to the output sharing. In some cases, the controller 9 may generate power by applying a part of the driving force of the engine 21 to the first motor 8 and may control each device so as to charge the main battery 2 with the electric power.

  The first motor 8 mainly functions as a cell motor and a generator. The second motor 18 mainly generates driving force. However, when a high driving force is required, the first motor 8 also supplies the driving force, and the second motor 18 also functions as a generator during regeneration.

  The output (drive torque) of the first motor 8, the output (drive torque) of the second motor 18 and the output (drive torque) of the engine 21 are synthesized / distributed by the power distribution mechanism 22 and transmitted to the axle 23 (axle). . The axle 23 is connected to the wheel 25 via a differential gear 24. The first motor 8 and the second motor 18 rotate in conjunction with the axle 23 and the engine 21.

  The power distribution mechanism 22 will be described. The power distribution mechanism 22 is mainly composed of a planetary gear. FIG. 2 shows a skeleton diagram of the planetary gear 50 constituting the power distribution mechanism 22. The planetary gear 50 is a gear set in which a sun gear 51, a planetary carrier 52, and a ring gear 53 are combined. The planetary carrier 52 is connected to the output shaft of the engine 21. The sun gear 51 is connected to the output shaft of the first motor 8 (M1). The ring gear 53 is connected to the second motor 18 (M2). A part of the ring gear 53 constitutes the rotor of the second motor 18. The ring gear 53 is engaged with the axle 23 via an output gear 54 that is coaxially fixed to the ring gear 53 and an idle gear 55. 2 is a transmission gear fixed to the axle 23. The output torque of the axle 23 is determined by the sum of the outputs of the engine 21, the first motor 8, and the second motor 18 by the power distribution mechanism 22 having the above configuration. In some cases, the axle 23 is driven by the outputs of the engine 21 and the second motor 18, and the first motor 8 is rotated by the driving force of the engine 21 to obtain electric power. Alternatively, the engine 21, the first motor 8, and the second motor 18 may all output to obtain a large driving force. The above case is the HV mode using the engine and the motor. Further, when the engine 21 is stopped, the outputs of the first motor 8 and the second motor 18 can be transmitted to the axle 23. The EV mode is a state in which the engine 21 is stopped and the vehicle travels with at least one driving force of the first motor 8 and the second motor 18.

  Since the structure and function of the planetary gear 50 are well known, detailed description thereof will be omitted. As is clear from FIG. 2, both the first motor 8 and the second motor 18 rotate in conjunction with the engine 21 and the axle 23. That is, even if the accelerator is turned off during traveling, the motor continues to rotate. At this time, the counter electromotive force generated by the motors 8 and 18 is converted into DC power via the inverters 7 and 17 and stored in the main battery 2. Alternatively, a part of the generated electric power is directly supplied to another electric device. That is, the hybrid vehicle 100 can also regenerate the kinetic energy of the vehicle into electrical energy and store it in the battery 2. Since the main battery 2 can be charged with regenerative electric power, the capacity of the main battery 2 is smaller than that of an electric vehicle without an engine.

  Returning to FIG. 1, the electrical system of the hybrid vehicle 100 will be described. The hybrid vehicle 100 includes two batteries 2 and 27. The main battery 2 is a high output and high capacity battery that stores electric power supplied to the motors 8 and 18. The sub-battery 27 is a battery for supplying electric power to an electric device other than the motor, for example, an electric device driven by 12 volts, such as a car navigation device 28 or a room lamp. In this embodiment, the output voltage of the sub battery 27 is 12 volts, but the output voltage of the sub battery is not limited to 12 volts. While the output voltage of the main battery 2 is generally 100 volts or more, the output voltage of the sub battery is generally 50 V or less. An electric device that operates with the power of the sub-battery 27 may be referred to as an auxiliary device. An inverter and a converter described later are also auxiliary machines. Further, since the power of the main battery 2 is also supplied to the auxiliary machine via the step-down converter 26, the sub battery 27 supplies power to the auxiliary machine when the power supply from the main battery 2 is stopped.

  The main battery 2 is connected to the buck-boost converter 5 via the system main relay 3. The system main relay 3 corresponds to a so-called main switch that connects or disconnects the main battery 2 and the electric system of the vehicle. The system main relay 3 is controlled by a controller 9.

  A first inverter 7 and a second inverter 17 are connected in parallel to the tip of the step-up / down converter 5. A first motor 8 is connected to the tip of the first inverter 7, and a second motor 18 is connected to the tip of the second inverter 17. The step-up / down converter 5 is a DCDC converter, and has a function of boosting the output voltage of the main battery 2 to a voltage suitable for driving the first and second motors 8 and 18, and regenerative power (AC) of the first motor 8. Is input to the DC power output from the first inverter 7 to a voltage suitable for charging the main battery 2. Similarly, the step-up / step-down converter 5 has a function of reducing the DC power output from the second inverter 17 to a voltage suitable for charging the main battery 2 by using the regenerative power (AC) of the second motor 18 as an input.

  A smoothing capacitor 15 is connected to the low voltage side (battery side) of the step-up / down converter 5, and a smoothing capacitor 16 is connected to the high voltage side (inverter side). The smoothing capacitors 15 and 16 are inserted in order to smooth the input current and output current of the buck-boost converter 5. Since a large current for driving the motor flows through the buck-boost converter 5, the smoothing capacitors 15 and 16 also have a large capacity.

  An example of the circuit of the buck-boost converter 5 is shown in FIG. The buck-boost converter 5 has two switching circuits SW1 and SW2 connected in series between terminals on the high voltage side (inverter side), and one end connected to the positive electrode (P1) on the low voltage side (battery side). The other end is constituted by a reactor 31 connected to the midpoint of the two switching circuits. The switching circuit SW1 between the reactor 31 and the high-voltage side positive terminal P2 is composed of an anti-parallel circuit of an IGBT 32 and a diode 33. The switching circuit SW2 between the reactor 31 and the negative terminal N on the high voltage side is composed of an anti-parallel circuit of an IGBT 34 and a diode 35. As is well known, when the IGBT 32 is opened (turned off) and a predetermined PWM signal is applied to the IGBT 34, a voltage higher than the voltage of the battery 2 can be output to the high voltage side through the reactor 31 and the diode 33. it can. Further, when the IGBT 34 is opened (turned off) and a predetermined PWM signal is applied to the IGBT 32, a voltage lower than the voltage output by the first inverter 7 during regeneration is passed through the reactor 31 and the diode 35 on the low voltage side (battery side). Can be output. The IGBT 32 is sometimes called an upper arm, and the IGBT 34 is sometimes called a lower arm.

  Returning to FIG. 1, the description will be continued. The first inverter 7 converts the DC power of the main battery 2 boosted by the step-up / down converter 5 into AC power suitable for driving the first motor 8 and outputs the AC power to the first motor 8. The output to the motor is UVW 3-phase AC power. The first inverter 7 also has a function of converting regenerative power (AC) generated by the first motor 8 into DC. That is, the first inverter 7 converts the output power of the main battery 2 into alternating current and supplies it to the first motor 8 when the first motor 8 outputs driving force, and the first motor 8 generates power. Converts the alternating current power generated by the first motor 8 into direct current and supplies the direct current power to the battery 2 and / or an auxiliary device (electric device) such as the car navigation device 28. The function of the second inverter 17 is also the same as that of the first inverter 7.

  The first inverter 7 and the second inverter 17 operate with a PWM signal. Similarly, the buck-boost converter 5 operates with a PWM signal. Further, the step-down converter 26 is also operated by a PWM signal. These PWM signals are generated by the controller 9 and transmitted to each device.

  A voltage sensor (low voltage side voltage sensor 4) is provided between the main battery 2 and the step up / down converter 5, in other words, between two terminals on the low voltage side of the voltage step up / down converter 5. A voltage sensor (high voltage side voltage sensor 6) is also provided between the step-up / down converter 5 and the first inverter 7, in other words, between the high-voltage side terminals of the step-up / down converter 5. The low voltage side voltage sensor 4 measures the output voltage of the main battery 2. The high voltage side voltage sensor 6 measures the output of the step-up / down converter 5 during powering, that is, the input voltage of the first inverter 7. The voltage measured by the high voltage side voltage sensor 6 corresponds to the DC output voltage of the first inverter 7 during regeneration. The measured values of the voltage sensors 4 and 6 are sent to the controller 9.

  When the battery voltage measured by the low-voltage side voltage sensor 4 is lower than a predetermined threshold voltage, the controller 9 starts the engine and sets the HV to a high possibility that a failure has occurred in the main battery 2 or its peripheral components. Enter mode. While the battery voltage is lower than the threshold voltage, the controller 9 prohibits the transition to the EV mode. In other words, at this time, the controller 9 maintains the operation of the engine 21. While prohibiting the transition to the EV mode, the controller 9 checks whether or not the low-voltage side voltage sensor 4 has failed, and if the low-voltage side voltage sensor 4 has failed, the main battery 2 Cancels the prohibition of the EV mode on the assumption that the probability of being normal is high. In addition, since the probability that a failure will occur at two locations at the same time is extremely small, if there is a high probability that the low-voltage side voltage sensor 4 has failed, the main battery 2 may be determined to be normal. Next, the process of the controller 9 based on the measured value of the low voltage side voltage sensor 4 will be described in detail.

  FIG. 4 shows a flowchart of processing executed by the controller 9. Hereinafter, the voltage value measured by the low voltage side voltage sensor 4 is represented by VL (low voltage side voltage VL), and the voltage value measured by the high voltage side voltage sensor 6 is represented by VH (high voltage side voltage VH). The low-voltage side voltage VL and the high-voltage side voltage VH are also shown in FIG.

  The controller 9 constantly monitors the low-voltage side voltage VL, and when the low-voltage side voltage VL falls below a predetermined threshold voltage VLth, starts the processing of the flowchart of FIG. The threshold voltage VLth is set to the lower limit value of the output voltage range of the main battery 2 when the main battery 2 is normal. More precisely, the threshold voltage VLth is a value that is further lowered by some margin from the aforementioned lower limit value. The margin is a voltage sensor measurement error or the like. The threshold voltage VLth is determined in advance by the performance of the main battery 2 and the characteristics of the electric system of the hybrid vehicle 100 and is stored in the controller 9.

  When the battery abnormality process is started, the controller 9 first checks whether or not the engine 21 is operating at that time (S3). When the engine 21 is stopped (S3: NO), the controller 9 starts the engine 21 (S4). Since the engine 21 is started, the HV mode is set thereafter. Thereafter, the controller 9 does not stop the engine until step S12 (described later) is performed or until the main switch of the vehicle is turned off by the driver. That is, the controller 9 thereafter prohibits the transition to the EV mode (S5). While the transition to the EV mode is prohibited, the first motor 8 generates power with the driving force of the engine. At this time, the hybrid vehicle 100 continues to travel by the driving force of the engine 21 and the second motor 18.

  The AC power generated by the first motor 8 is converted into DC by the first inverter 7. Since the direct current side of the first inverter 7 is connected in parallel with the direct current side of the second inverter 17, a part of the electric power generated by the first motor 8 flows from the first inverter 7 to the second inverter 17, 2 Electric power for driving the motor 18. A step-up / down converter 5 is connected to the DC side of the first inverter 7. Therefore, another part of the electric power generated by the first motor 8 is supplied to an electric device such as the car navigation apparatus 28 through the step-up / down converter 5 and the step-down converter 26. The controller 9 sets the first inverter 7 so that a value obtained by adding the power consumption of the second motor 18 and the power consumption of the electrical device group connected to the sub-battery 27 is substantially equal to the power generated by the first motor 8. To control. In order to balance the power balance, the controller 9 may include not only the first inverter 7 but also the engine 21 that determines the rotation of the first motor 8 and / or the second inverter 17 that determines the output of the second motor 18. Also controls. In other words, balancing the power balance corresponds to the controller 9 controlling the first inverter 7 and the like so that the high-voltage side voltage VH is constant (S6). Specifically, the controller 9 monitors the measurement value VH of the high voltage side voltage sensor 6 and controls the first inverter 7 (and the engine 21 and the second inverter 17) so that the measurement value VH is constant. If the high-voltage side voltage VH can be kept constant, that is, if the power generated by the first motor 8 and the power consumption of the second motor 18 and the on-vehicle electric device are balanced, the power is supplied from the main battery 2. Therefore, the vehicle can be continuously driven by the driving force of the engine 21 and the second motor 18. This is battery-less travel. Strictly speaking, maintaining the high voltage VH at a constant level is the power generated by the first motor 8 and the power consumed by the second motor 18 and other electrical devices plus the inverter and converter losses. Is to balance.

  When step S6 is executed, the power that can be used for powering is limited by the amount of power generated by the first motor 8, and therefore the rated maximum output of the second motor 18 cannot be produced. That is, it should be noted that at this time, the hybrid vehicle 100 cannot output the normal maximum output. Specifically, even if the driver strongly depresses the accelerator pedal, the output (drive torque) of the hybrid vehicle 100 is limited to a value lower than the originally planned output.

  Since the input / output terminal of the step-up / step-down converter 5 is short-circuited in the next step S7, when the controller 9 maintains the high-voltage side voltage VH (voltage generated by the first motor 8) constant in step S6, the voltage VH is Then, the rotational speed of the engine 21 that drives the first motor 8 and the first inverter 7 that converts the generated AC power into DC power are controlled so as to be lower than the allowable voltage of the main battery 2.

  Next, the controller 9 closes the transistor (IGBT 32) of the upper arm (switching circuit SW1) of the step-up / down converter 5 and short-circuits the low-voltage side positive terminal P1 and the high-voltage side positive terminal P2 of the step-up / down converter 5 (S7). . P1 and P2 are shown in FIG. Note that the negative electrode terminal on the low voltage side and the negative electrode terminal on the high voltage side are originally connected. Next, the controller 9 checks whether or not the low voltage side voltage VL coincides with the high voltage side voltage VH (S8). Here, since there is an error in the measured value of the voltage sensor, the process of step S8 is as follows in more detail. That is, the controller 9 checks whether or not the difference between the low-voltage side voltage VL and the high-voltage side voltage VH is within a predetermined error range. This predetermined error range may include a margin in addition to the measurement error. Since the input / output terminal of the step-up / down converter 5 is short-circuited, the low-voltage side voltage VL coincides with the high-voltage side voltage VH unless the voltage sensor has failed (S8: YES). In this case, since there is a high possibility that an abnormality (for example, disconnection or contact failure) has occurred in the main battery 2 or the power supply line from the main battery 2, the controller 9 connects the system main relay 3 (see FIG. 1). The main battery 2 is disconnected from the circuit (S9). Thereafter, the hybrid vehicle 100 continues battery-less travel.

  Conversely, when the low voltage side voltage VL does not coincide with the high voltage side voltage VH (S8: NO), there is a high probability that the voltage sensor has failed. In general, since the probability that two locations will fail simultaneously is extremely low, if the voltage sensor is faulty (ie, if the determination in S8 is NO), it is determined that the probability that the main battery 2 has not failed is extremely high. it can. In this case, since it is not necessary to prohibit the engine stop, the controller 9 cancels the engine stop prohibition set in step S5 (S12). In other words, the controller 9 allows the transition to the EV mode. After step S12, the controller 9 returns to normal running where the EV mode and the HV mode are appropriately switched.

  Advantages of the hybrid vehicle 100 according to the embodiment will be described. When an abnormality occurs in the main battery 2 or the vicinity thereof, the hybrid vehicle 100 shifts to battery-less traveling that does not rely on battery power while maintaining the operation of the engine. In addition, when a problem occurs in the main battery 2 or its surroundings, it is possible to run only with the engine without using the motor. However, since a hybrid vehicle is based on the premise that a high driving force is obtained by combining an engine output and a motor output, a sufficient driving force cannot be produced only by the engine. The hybrid vehicle 100 disclosed in the present specification can travel using the engine and the motor without depending on the battery even if a failure occurs in the main battery 2 or its surroundings. Can travel with a corresponding driving force.

  Examples of abnormalities in the main battery 2 or its surroundings include disconnection or poor contact of the power supply line inside the main battery 2 or from the main battery 2 to the buck-boost converter 5. Since the large-capacity smoothing capacitors 15 and 16 are connected in parallel on the low-voltage side and the high-voltage side of the step-up / down converter 5, even if the power supply line from the main battery 2 is disconnected, these smoothing capacitors Since power is supplied, power does not become zero instantly.

  When the measured value VL of the low-voltage side voltage sensor 4 falls below the voltage threshold value VLth, the controller 9 of the hybrid vehicle 100 once prohibits the EV mode, but then checks whether or not the low-voltage side voltage sensor 4 has failed. . When the low voltage side voltage sensor 4 is not broken (when the low voltage side voltage VL and the high voltage side voltage VH match), it is determined that a failure has occurred in the main battery 2 or its surroundings, and the system main relay 3 is opened and batteryless running is continued. On the other hand, when the low-voltage side voltage sensor 4 is out of order (when the low-voltage side voltage VL and the high-voltage side voltage VH do not match), the probability that a failure has occurred in the main battery 2 or its surroundings is low. Return to normal driving. That is, the prohibition of engine stop set in step S5 is canceled and the transition to the EV mode is permitted.

  Further, the hybrid vehicle 100 according to the embodiment adjusts the high-voltage side voltage VH to be within the allowable voltage of the main battery 2 prior to short-circuiting the input / output terminal of the step-up / down converter 5 in step S7 of FIG. . By doing so, the main battery 2 is protected even when the input / output terminal of the step-up / down converter 5 is short-circuited.

  Points to be noted regarding the technology of the embodiment will be described. When the main battery 2 is detachable, a unique voltage sensor may be provided inside the main battery 2. Therefore, in step S12 (that is, when there is a high possibility that the low voltage side voltage sensor 4 has failed), the controller 9 replaces the measured value of the voltage sensor in the main battery with the measured value of the low voltage side voltage sensor 4. It is also suitable to use for.

  The process of the flowchart of FIG. 4 is described in a program installed in the controller 9.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: main battery 3: system main relay 4: low voltage side voltage sensor 5: buck-boost converter 6: high voltage side voltage sensor 7: first inverter 8: first motor 9: controller 15, 16: smoothing capacitor 17: second Inverter 18: Second motor 21: Engine 22: Power distribution mechanism 23: Axle 26: Step-down converter 27: Sub battery 31: Reactor 32, 34: IGBT
33, 35: Diode 50: Planetary gear 51: Sun gear 52: Planetary carrier 53: Ring gear 100: Hybrid vehicle VH: High voltage side voltage VL: Low voltage side voltage (battery output voltage)

Claims (3)

It is a hybrid vehicle that can switch between EV mode, which uses only the motor without using the engine, and HV mode, which runs using the engine and motor,
A battery for storing electric power for driving the motor;
A converter that boosts the output voltage of the battery;
A first motor used for both outputting a driving force for driving wheels and generating electric power by driving force of an engine or deceleration energy of a vehicle;
A second motor that outputs a driving force for driving the wheels;
When outputting driving force to the first motor, the output power of the converter is converted to alternating current and supplied to the first motor. When the first motor generates power, the alternating current power generated by the first motor is converted to direct current. A first inverter for supplying direct current power to an electric device including a battery or a second motor;
A second inverter that converts the output power of the converter into alternating current and supplies the second motor;
A low voltage side voltage sensor for measuring the voltage between the low voltage side terminals of the converter;
A high voltage sensor that measures the voltage between the high voltage terminals of the converter;
A controller, and the controller performs the following processing:
(1) The EV mode is prohibited when the measured value of the low-voltage side voltage sensor falls below a predetermined threshold voltage, and the power balance between the power obtained by the power generation of the first motor and the power consumption of the electrical device. Control the first inverter so that
(2) When the low voltage side terminal and the high voltage side terminal of the converter are short-circuited and the measured value of the low voltage side voltage sensor matches the measured value of the high voltage side voltage sensor, the EV mode prohibition is maintained.
(3) Cancel the EV mode prohibition when the measured value of the low voltage side voltage sensor is lower than the measured value of the high voltage side voltage sensor despite the short circuit between the low voltage side terminal and the high voltage side terminal of the converter.
A hybrid vehicle characterized by executing processing.   The output shaft of the first motor is connected to the sun gear, the output shaft of the engine is connected to the planetary carrier, the output shaft of the second motor is connected to the ring gear, and the planetary gear is connected to the axle. The hybrid vehicle according to claim 1, further comprising: The converter has two switching circuits connected in series between the high-voltage side terminals, one end connected to the positive terminal on the low-voltage side, and the other end connected to an intermediate point between the two switching circuits. It consists of a reactor,
3. The hybrid vehicle according to claim 1, wherein the controller short-circuits the low-voltage side terminal and the high-voltage side terminal by closing a switching circuit between the high-voltage side positive electrode terminal of the converter and the reactor.

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