JP2009012508A - Control unit of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a switching operation with high durability for recovering a battery by preparing two inverters 23, 24 connected to one motor 25 and by using the motor 25, and for effectively utilizing the inverters 23, 24, and achieving an operation with high efficiency of a power supply system. <P>SOLUTION: Either one of a first and a second inverters 23, 24 is operated when a recovery current Ire is smaller than a prescribed reference current Imr, and both of them are operated when the recovery current Ire is larger than the reference current Imr. Provided are a DC-DC converter 31 as a boosting means, which boosts a DC bus line 22 until the path voltage Vdc becomes equal to or higher than the motor voltage Vm if a path voltage Vdc is lower than a motor voltage Vm while the second inverter 24 is turned off in recovery operation of the motor 25, and a relay control unit 111 which switches a relay switch 29 if the path voltage Vdc is equal to or higher than the motor voltage Vm when the second inverter 24 is turned off. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle control device, and more particularly to a hybrid vehicle control device suitable for a series hybrid vehicle.

  A series hybrid vehicle is a vehicle in which a generator is driven by an engine, electric power is supplied from the generator to a motor, and driving wheels are driven by the motor, as disclosed in Patent Document 1, for example. Unlike parallel hybrid vehicles, in series hybrid vehicles, the engine is used exclusively for power generation, and the power generated by the engine is not mechanically transmitted to the drive wheels.

In such a hybrid vehicle, as shown in Patent Document 1, after the generator current driven by the engine is rectified by a rectifier, one inverter is connected to one motor connected to the drive system of the vehicle. A connected configuration is disclosed.
JP 2005-204370 A

  As disclosed in Patent Document 1, an ordinary hybrid vehicle generally includes one inverter for one motor. On the other hand, the present inventor provided two inverters to drive one motor, and connected one inverter to the motor at all times, and the other inverter intervened with switching means to Accordingly, we are studying battery regeneration by the motor, effective use of the inverter, and high-efficiency operation of the power feeding system by cutting off the connection to the motor.

  However, when an insulated gate bipolar transistor (IGBT) is used as such a switching means, there is a problem that the efficiency of the power feeding system decreases because of a large loss.

  Therefore, in order to maintain the efficiency of the power feeding system, it is preferable to use a relay switch. However, in the case of using a relay switch, there is a problem that deterioration is easily caused when a switching operation is performed during energization. In addition, since an element in which an insulated gate bipolar transistor is combined with a diode is widely used for the inverter, the relay switch current may not be zero during regeneration even when the inverter is OFF. There was a problem that the switching operation was hindered.

  The present invention has been made in view of the above problems, and two inverters connected to one motor are provided to regenerate a battery by the motor, to effectively use the inverter, and to perform a highly efficient operation of the power feeding system. Therefore, an object of the present invention is to provide a control device for a hybrid vehicle that can perform a highly durable switching operation.

  In order to solve the above problems, the present invention includes a generator driven by an engine to generate an alternating current, a motor that drives the vehicle and also functions as a regenerative generator when the vehicle is decelerated, and the generator generates power. A rectifier that rectifies the alternating current, a first inverter that is connected to a power supply path between the rectifier and the motor, and that converts a direct current in the power supply path into an alternating current; and in parallel with the first inverter A second inverter connected to the power supply path, a relay switch provided between the second inverter and the motor, and capable of disconnecting the second inverter from the motor; and the power supply path And a power supply path voltage detecting means for detecting a voltage of the power supply path as a path voltage. Motor voltage detection means for detecting the voltage of the motor as a motor voltage, current calculation means for calculating the current to be supplied to both inverters, and the current calculated by the current calculation means is less than a predetermined reference current When one of the first and second inverters is operated, and when the current calculated by the current calculation means is larger than the reference current, an inverter control unit that operates both and the regeneration of the motor When the second inverter is turned off during operation and the path voltage is lower than the motor voltage, the boosting unit boosts the power feeding path until the path voltage becomes equal to or higher than the motor voltage; and the motor When the second inverter is turned off during the regenerative operation, the relay switch is turned off when the path voltage is equal to or higher than the motor voltage. It is a control apparatus for a hybrid vehicle according to claim that a relay control unit to. In this aspect, when the second inverter is shut off from the operating state in which both inverters are operating during the regenerative operation of the motor, the current flowing from the motor to the second inverter is reduced as much as possible. The switch can be switched safely. That is, at the time of regeneration, in the driving situation where the path voltage is lower than the motor voltage, even if the second inverter is turned off, the current from the motor to the second inverter is caused by the action of the diode provided in the second inverter. Therefore, by stopping the step-down operation by the switching circuit, the path voltage is increased, and the relay switch is turned off when the path voltage is equal to or higher than the motor voltage.

  In a preferred aspect, the vehicle includes a switching circuit that is interposed between the battery and the power supply path and adjusts the level of a direct current, and the step-up unit performs a step-down operation of the switching circuit to reduce the battery voltage. Stops the step-down operation of the switching circuit when causing the motor to perform a regenerative operation and when the second inverter is turned off during the regenerative operation of the motor and the path voltage is lower than the motor voltage. A switching circuit control unit is included. In this aspect, the switching circuit control unit that controls the regenerative operation of the hybrid vehicle executes the boosting operation of the power feeding path. Therefore, when boosting the power feeding path, the regeneration operation is also stopped, so that the power feeding path is boosted more efficiently. The relay switch can be switched quickly.

  In a preferred aspect, the switching circuit control unit is configured such that when the second inverter is turned off during the regenerative operation of the motor and the path voltage is lower than the motor voltage, the path voltage and the motor voltage When the difference is less than a predetermined determination voltage, the step-down operation is stopped, and when the difference between the path voltage and the motor voltage is greater than or equal to the determination voltage, the switching circuit is boosted. In this aspect, it is possible to perform suitable voltage control according to the operating state and switch the relay switch. In other words, when the voltage step-down operation is simply stopped and the power supply path is boosted, it tends to take time until the relay switch is switched. On the other hand, when the switching circuit is boosted, the battery goes from the power supply path to the power supply path. However, it is possible to optimize the mode of boosting the power feeding path by comparing the difference between the path voltage and the motor voltage with a predetermined determination voltage.

  In a preferred aspect, a capacitor is connected to the power supply path. In this aspect, when the switching circuit control unit as the boosting unit boosts the power feeding path by the boosting operation, the power from the battery to the power feeding path is stored in the capacitor, so that the loss due to the boosting operation is reduced as much as possible. be able to.

  As described above, the present invention enables the current flowing from the motor to the second inverter when the second inverter is shut off from the operating condition in which both inverters are operating during the regenerative operation of the motor. Therefore, the relay switch can be switched safely, so two inverters connected to one motor are provided, battery regeneration by the motor, effective use of the inverter, and high-efficiency operation of the power feeding system In order to achieve this, there is a remarkable effect that a highly durable switching operation can be performed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  Note that, in the following embodiments, the same members are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention, and FIG. 2 is a wiring diagram showing a main part of the hybrid vehicle.

  With reference to FIG. 1, the hybrid vehicle according to the present embodiment is a series hybrid vehicle having an engine 10 and a generator 20 driven by the engine 10.

  The engine 10 is, for example, a multi-cylinder four-cycle gasoline engine, and includes a main body 11 that is configured by a cylinder head and a cylinder block, a plurality of rows of cylinders 12 formed in the main body 11, and new cylinders 12. An intake manifold 14 for introducing air and an exhaust manifold 15 for discharging the burned gas of each cylinder 12 are provided. A fuel injection valve 16 and a spark plug 17 provided corresponding to each cylinder 12 are attached to the main body 11. And it is comprised so that the crankshaft 10a connected to the said piston may be driven by raising / lowering the piston provided in each cylinder 12. As shown in FIG. The intake manifold 14 is provided with a throttle valve 18 for adjusting the amount of fresh air, and is driven by an actuator 19 of the throttle body.

  Referring also to FIG. 2, generator 20 is, for example, a three-phase multi-phase motor generator connected to crankshaft 10 a of engine 10, and outputs an alternating current when driven by engine 10. Is configured to function also as a motor for starting the engine 10. The generator 20 is provided with a generator output current sensor SW1 that detects the output current and a generator rotation speed sensor SW2 that detects the rotation speed.

  The generator 20 is connected to a diode rectifier 21. The diode rectifier 21 has a plurality of sets of diodes D <b> 1 to D <b> 6 corresponding to the number of phases n of the generator 20. The output terminal of the diode rectifier 21 is connected to a DC bus line 22 as a power feeding path.

  A capacitor C <b> 1 is connected to the DC bus line 22. The DC bus line 22 is connected to a DC bus line voltage sensor SW3 that detects the voltage of the DC bus line 22 as a path voltage Vdc.

  In the present embodiment, first and second inverters 23 and 24 are connected in parallel to the DC bus line 22. Each inverter 23 and 24 has a plurality of sets of elements Q11 to Q16 and Q21 to Q26 corresponding to the number of phases of the multiphase motor 25 serving as a load. Each of the elements Q11 to Q16 and Q21 to Q26 is configured by a transistor, a diode, or the like. In the present embodiment, the rated current Ir of each of the inverters 23 and 24 is set slightly larger than half of the current required for the maximum output of the motor 25.

  The first inverter 23 is connected to the motor 25. The motor 25 is connected to a differential mechanism 26 of the hybrid vehicle, and drives the axle 28 on the rear wheel 27 side of the hybrid vehicle via the differential mechanism 26. In addition, the motor 25 in the present embodiment is configured to function also as a battery regeneration generator.

  The second inverter 24 is connected to the relay switch 29. The relay switch 29 serves as a contact point between a normal operation power supply path 29 a that connects the second inverter 24 to the generator 20 and a starter operation power supply path 29 b that connects the second inverter 24 to the motor 25. The second inverter 24 can be selectively connected to any one of the paths 29a and 29b, and the second inverter 24 can be turned off so as not to be connected to either the generator 20 or the motor 25. . As a result, the second inverter 24 causes the alternating current to flow through the motor 25 together with the first inverter 23 according to the operating state, or the generator 20 is energized to drive the engine 10 at the start, or completely Or is cut off from the power supply system.

  Further, a power supply device 30 is connected to the DC bus line 22. The power supply device 30 includes a DC-DC converter 31 as a switching circuit and a battery 32 connected to the DC-DC converter 31.

  The DC-DC converter 31 includes a step-up element Q1, a step-down element Q2, and a reactor L. Each of the elements Q1 and Q2 includes a transistor. By turning on / off the transistor of the step-up element Q1 at a predetermined timing and keeping the transistor of the step-down element Q2 off, the battery 32 stores electricity in the reactor L. By setting the side to a high voltage and allowing current to flow from the battery 32 to the DC bus line 22, the transistor of the step-down element Q2 is turned ON / OFF at a predetermined timing, and the transistor of the step-up element Q1 is maintained OFF The DC bus line 22 is set to a high voltage so that a current flows from the DC bus line 22 to the battery 32.

  The power supply device 30 is provided with a battery current sensor SW4 that detects a current flowing through the battery 32 as a battery current Ib, and a battery voltage sensor SW5 that detects a voltage of the battery 32 as a battery voltage Vb.

  Further, the hybrid vehicle is provided with a vehicle speed sensor SW6, an accelerator opening sensor SW7, and a brake sensor SW8 in order to detect the driving state of the vehicle. Further, in order to detect the operation state of the motor 25, a motor rotation speed sensor SW11 that detects the rotation speed Nm of the motor 25 and a motor voltage sensor SW12 that detects the voltage of the motor 25 as the motor voltage Vm are provided in the motor 25. It has been.

  FIG. 3 is a block diagram showing a control apparatus for the hybrid vehicle shown in FIG.

  Referring to FIG. 3, the hybrid vehicle shown in FIG. 1 is controlled by a control unit (PCM: Powertrain Control Module) 100 as a control means.

  The control unit 100 is a microprocessor including a CPU, a memory, and the like. The control unit 100 reads a detection signal from an input element by a program module, executes predetermined arithmetic processing, and outputs a control signal to the output element. In the example shown in the figure, the control unit 100 is shown as one unit, but as a specific aspect, a module assembly in which a plurality of units are combined may be used.

  The input elements of the control unit 100 include a generator output current sensor SW1, a generator rotation speed sensor SW2, a DC bus line voltage sensor SW3, a battery current sensor SW4, a battery voltage sensor SW5, a vehicle speed sensor SW6, an accelerator opening sensor SW7, and a brake sensor. SW8, motor rotation speed sensor SW11, and motor voltage sensor SW12 are included. Although not specifically shown, various sensors (a water temperature sensor, a rotation angle sensor, a throttle opening sensor, etc.) provided in the engine 10 are also connected to control the combustion of the engine 10. .

  The output elements of the control unit 100 include a fuel injection valve 16, a spark plug 17, a throttle valve actuator 19, first and second inverters 23 and 24, a relay switch 29, and a DC-DC converter 31.

  In the illustrated example, the control unit 100 includes an operation state determination unit 101, a combustion control unit 110 that performs operation control of the engine 10, a relay control unit 111 that performs power supply control by control of the relay switch 29, and a DC− A battery control unit 112 as a switching circuit control unit that controls the DC converter 31 and an inverter control unit 113 are logically provided.

  The driving state determination unit 101 determines the driving state of the hybrid vehicle based on detection of the sensors SW1 to SW7. In the present embodiment, the driving state determination unit 101 has a function of determining whether or not there is a request for engine operation of the hybrid vehicle, or a predetermined regeneration condition (for example, when the vehicle is decelerating and the charged amount of the battery 32 is less than or equal to a predetermined value). And the like, and a function for determining success or failure of the regeneration end condition for determining that the regeneration condition has ended.

  The combustion control unit 110 is configured to control the rotational speed of the engine 10 by controlling the fuel injection valve 16, the spark plug 17, the throttle valve actuator 19, and the like, thereby controlling the rotational speed of the generator 20. .

  The relay control unit 111 switches the relay switch 29 based on the determination result of the operation state determination unit 101 to connect the second inverter 24 to the motor 25 from the normal operation power supply path 29a, and the first power supply mode. 2 is connected to the generator 20 from the starter operation power supply path 29b, and the generator 20 is driven as a motor to start the engine 10, and the second inverter 24 is connected to the generator 20 and the motor 25. Is also switched to the OFF mode that is not connected. The memory of the control unit 100 is provided with an area for storing a switching control flag F for controlling the switching operation of the relay switch 29. Based on the value of the switching control flag F, the relay control unit 111 is provided. Is configured to control the switching operation of the relay switch 29. In this embodiment, when the value of the switching control flag F is 0, the OFF mode is set, and when it is 1, the motor power supply mode is set, and when it is 2, the starter power supply mode is set.

  Based on the outputs of the battery current sensor SW4 and the battery voltage sensor SW5, the battery control unit 112 normally maintains a constant output current from the battery 32 when the power supply device 30 is used, or an overcurrent during battery regeneration. Plays a function to prevent or. Along with this, it has a function of causing the DC-DC converter 31 to perform a step-down operation or a step-up operation in accordance with a driving situation in detail according to a flowchart described later.

  The inverter control unit 113 controls the ON / OFF operation of the first and second inverters 23 and 24 based on the determination result of the operation state determination unit 101 to optimize the load state of each inverter 23 and 24 with respect to the power supply target. To control.

  The control unit 100 controls the engine 10, the generator 20, the first and second inverters 23 and 24, the motor 25, the relay switch 29, the DC-DC converter 31, and the like based on the determination result of the operation state determination unit 101. . By this control, the relay switch 29 is switched to connect the second inverter 23 to the motor 25 in the driving region when the vehicle is started or at low torque, and the power of the battery 32 is supplied to the first and second inverters 23, 24 is supplied to the motor 25, and the vehicle is driven based on the power supply of the battery 32. Further, in an operation region where the required load is medium to high torque, the relay control unit 111 switches the relay switch 29 to the starter power supply mode based on a flowchart described later, thereby starting the engine 10 and using the generator 20 as a generator. After the engine 10 is started, the motor 25 is mainly driven from the first inverter 23 by the current supplied from the generator 20.

  Here, in the present embodiment, in order to operate the first and second inverters 23 and 24 in the high efficiency region, the operation rates of the inverters 23 and 24 are changed according to the amount of current.

  FIG. 4 is a characteristic diagram of the inverter.

  Referring to FIG. 4, first and second inverters 23 and 24 have diodes like elements Q11 to Q16 and Q21 to Q26 shown in FIG. For this reason, in the operating region where the load factor (output current) is low, the efficiency is remarkably reduced. Therefore, in this embodiment, when the current required for power supply is small, the inverter is operated with one inverter (mainly the second inverter 24) turned off, thereby increasing the load factor of the operating inverter, and the inverter The efficiency of the power supply system is improved by increasing its own efficiency.

  By the way, when switching the inverters 23 and 24 to be operated, it is necessary to operate the relay switch 29. On the other hand, if the switching operation of the relay switch 29 is performed when there is a current, the relay switch 29 deteriorates severely and its life is shortened. Therefore, in this embodiment, when it is necessary to switch the relay switch 29 during energization, the current of the relay switch 29 is once set to 0 to perform the switching operation.

  Next, a control example of the regenerative operation of this embodiment will be described.

  5 and 6 are flowcharts showing an example of control of the regenerative operation according to the present embodiment.

  Referring to FIG. 5, in this flowchart, operation state determination unit 101 waits for the regeneration condition to be satisfied (step S1). When the regeneration condition is satisfied, the operation state determination unit 101 reads the battery voltage Vb and the motor rotation speed Nm from the battery voltage sensor SW5 and the motor rotation speed sensor SW11, respectively (step S2). Next, the operating state determination unit 101 calculates a regenerative current Ire that the motor 25 will generate from the read battery voltage Vb and motor rotation speed Nm (step S3). Next, the operating state determination unit 101 compares the calculated regenerative current Ire with a predetermined reference current Imr, and determines whether or not the regenerative current Ire exceeds the reference current Imr (step S4). Here, the reference current Imr is set equal to the rated current Ir of each of the inverters 23 and 24.

  When the regenerative current Ire exceeds the reference current Imr, the operation state determination unit 101 determines whether or not the first and second inverters 23 and 24 are both operating (step S5). In this determination, when both the inverters 23 and 24 are in operation and the relay switch 29 connects the second inverter 24 to the normal operation power supply path 29a, both the inverters 23 and 24 are in operation. It is determined that there is.

  If it is determined that both the inverters 23 and 24 are operating, the step-down control of the DC-DC converter 31 is executed under the control of the battery control unit 112 (step S6). In this step-down control, the battery voltage Vb and the path voltage Vdc are compared, and when the path voltage Vdc is lower than the battery voltage Vb, the step-down operation is executed so that current flows from the DC bus line to the battery 32. Controlled. By this step-down control, the path voltage Vdc of the DC bus line 22 decreases, and the electric power generated by the motor 25 causes current to flow from the motor 25 to the DC bus line 22 via the inverters 23 and 24 and to be supplied to the battery 32. Become. Next, the driving state determination unit 101 determines whether or not a predetermined regeneration end condition is satisfied (step S7). For example, when the regeneration end condition is satisfied, for example, when the accelerator is depressed and the vehicle accelerates, the process ends. On the other hand, if the regeneration end condition is not satisfied, the process returns to step S2 and the process is repeated.

  In step S4, when the calculated regenerative current Ire is equal to or less than the reference current Imr, the first inverter 23 is turned on so that only the first inverter 23 is operated in view of the efficiency characteristics of the inverter described above. On the other hand, the second inverter 24 is turned off (step S8). At this time, the relay switch 29 also needs to be in the OFF mode, but the current of the relay switch 29 may not become 0 just by turning off the second inverter 24 at the time of regeneration. The value of the switching control flag F of the relay switch 29 is set to 0 (step S9), and thereafter, the relay switch 29 is switched through a process described later.

  In step S5, when only one inverter is operating or when none of the inverters is operating, the operation state determination unit 101 determines whether or not the relay switch 29 is connected to the motor side. (Step S10). If the relay switch 29 is connected to the motor side, since the switching operation of the relay switch 29 is not required, both the inverters 23 and 24 are operated as they are (step S11), and the process proceeds to the control after step S6. .

  On the other hand, in step S10, when the relay switch 29 is not connected to the motor side, in order to avoid switching of the relay switch 29 in a state in which the motor 25 and the second inverter 24 can be energized, first, 2 inverter 24 is turned off (step S12). Even at this timing, it is necessary to set the relay switch 29 in the OFF mode. However, the current of the relay switch 29 may not become 0 only by turning off the second inverter 24 at the time of regeneration. The value of the switching control flag F of the relay switch 29 is set to 1 (step S14), and thereafter, the relay switch 29 is switched through a process described later.

  Next, referring to FIG. 5, after step S9 or step S14 is executed, operation state determination unit 101 obtains motor voltage Vm and path voltage Vdc from motor voltage sensor SW12 and DC bus line voltage sensor SW3, respectively. Read (step S21).

  Next, the motor voltage Vm and the path voltage Vdc are compared to determine whether or not the motor voltage Vm is greater than the path voltage Vdc (step S22). If the motor voltage Vm is higher than the path voltage Vdc, even if the second inverter 24 is OFF, the current generated by the motor 25 passes through the diode included in the second inverter 24 to the DC bus line 22. Will flow. Therefore, in the present embodiment, the DC bus line 22 is boosted by stopping the step-down operation by the DC-DC converter 31 (step S23). Next, the operating state determination unit 101 determines whether or not the difference between the motor voltage Vm and the path voltage Vdc is smaller than a predetermined determination voltage Vst (step S24).

  FIG. 7 is a timing chart showing the rise characteristic of the path voltage due to the stop of the step-down operation.

  Referring to FIG. 7, if the difference between motor voltage Vm and path voltage Vdc is smaller than determination voltage Vst, DC bus line 22 is boosted relatively quickly even by stopping the step-down operation by DC-DC converter 31. To do. Therefore, in the present embodiment, when the difference between the motor voltage Vm and the path voltage Vdc is small, it waits for both voltages Vm and Vdc to be equal only by stopping the step-down operation of the DC-DC converter 31 (step S25). After the voltages Vm and Vdc become equal, the relay switch 29 is switched based on the value of the switching control flag F (step S26). As a result, when step S9 is reached from step S9 to step S26, the relay switch 29 is switched to the OFF mode by the relay control unit 111, while when step S14 is passed to step S26 via step S21. Then, the relay control unit 111 switches the relay switch 29 to the motor side. Thereafter, the operation state determination unit 101 refers to the value of the switching control flag F (step S27), and when the value is 0 (that is, when the relay switch 29 is turned off), the step-down control in step S6. Return to. As a result, the operation of the second inverter 24 is stopped when the regenerative current Ire decreases from the operating state in which the regenerative operation is performed by both the inverters 23 and 24, and the efficiency of the first inverter 23 alone is reduced. When performing a typical operation, the switching operation of the relay switch 29 can be performed in a state where no current flows, and the deterioration of the relay switch 29 can be suppressed.

  On the other hand, when the value of the switching control flag F is 1 in step S27 (that is, when the relay switch 29 is switched to the motor 25 side), the second inverter 24 is turned on (step S28). Returning to the step-down control in step S6. As a result, when the regenerative operation is performed by both inverters 23 and 24 from the operation state in which the regenerative operation is performed by one of the inverters, the switching operation of the relay switch 29 can be performed in a state where no current flows. The deterioration of the relay switch 29 can be suppressed.

  In step S24, when the difference between the motor voltage Vm and the path voltage Vdc is equal to or higher than the determination voltage Vst, the battery control unit 112 causes the DC-DC converter 31 to perform a boost operation (step S29).

  FIG. 8 is a timing chart showing the rise characteristic of the path voltage due to the boosting operation.

  Referring to FIG. 8, when the difference between motor voltage Vm and path voltage Vdc is equal to or higher than determination voltage Vst, it takes time to boost DC bus line 22 only by stopping the step-down operation by DC-DC converter 31. Therefore, in this embodiment, the DC bus is positively generated by the current flowing from the battery 32 by the boosting operation by the DC-DC converter 31 and the current flowing from the motor 25 to the DC bus line 22 by the difference between the motor voltage Vm and the path voltage Vdc. The line 22 is boosted. Here, in the present embodiment, since the capacitor C1 is provided in the DC bus line 22, the electricity discharged from the battery 32 can be stored in the capacitor C1, and as a result, the capacitor C1 is returned to the regenerative operation. Can be recovered by the battery 32. Therefore, even if the battery 32 is discharged and the DC bus line 22 is boosted, the loss of the battery 32 is reduced as much as possible.

  As described above, in the present embodiment, when the second inverter 24 is shut off from the operating state in which both the inverters 23 and 24 are operating during the regenerative operation of the motor 25, the second inverter 24 is switched from the motor 25. Therefore, the current flowing through the relay switch 29 can be reduced as much as possible, and the relay switch 29 can be switched safely.

  In the present embodiment, the DC-DC converter 31 is stepped down to cause the motor 25 to perform the regenerative operation of the battery 32, and the second inverter 24 is turned off during the regenerative operation of the motor 25. When the voltage Vdc is lower than the motor voltage Vm, the battery control unit 112 that stops the step-down operation of the DC-DC converter 31 is provided. The DC-DC converter 31 as the switching circuit and the battery control unit as the switching circuit control unit Reference numeral 112 functions as a booster. For this reason, in this embodiment, since the boost operation of the DC bus line 22 is executed by the battery control unit 112 that controls the regeneration operation of the hybrid vehicle, the regeneration operation is also stopped when the DC bus line 22 is boosted, resulting in higher efficiency. The DC bus line 22 can be boosted well and the relay switch 29 can be switched quickly.

  In the present embodiment, when the second inverter 24 is turned off during the regenerative operation of the motor 25 and the path voltage Vdc is lower than the motor voltage Vm, the difference between the path voltage Vdc and the motor voltage Vm is predetermined. When the voltage is lower than the determination voltage Vst, the step-down operation is stopped. On the other hand, when the difference between the path voltage Vdc and the motor voltage Vm is equal to or higher than the predetermined determination voltage Vst, the DC-DC converter 31 is boosted. For this reason, in this embodiment, suitable voltage control can be performed according to the driving | running state, and the relay switch 29 can be switched. That is, when the step-down operation is simply stopped to boost the DC bus line 22, it tends to take time until the relay switch 29 is switched, whereas when the DC-DC converter 31 is boosted. Although there is a tendency for loss due to power supply from the battery 32 to the DC bus line 22, the DC bus line 22 is boosted by comparing the difference between the path voltage Vdc and the motor voltage Vm with a predetermined determination voltage Vst. Can be optimized.

  In the present embodiment, a capacitor C <b> 1 is connected to the DC bus line 22. For this reason, in the present embodiment, when the battery control unit 112 as the boosting unit boosts the DC bus line 22, the power from the battery 32 to the DC bus line 22 is stored in the capacitor C1, so that the loss due to the boosting operation is reduced. It can be reduced as much as possible.

  The above-described embodiments are merely preferred specific examples of the present invention, and the present invention is not limited to the above-described embodiments.

  FIG. 9 is a schematic configuration diagram of a hybrid vehicle according to another embodiment of the present invention.

  In the embodiment of FIG. 9, an AC / DC converter 60 is employed instead of the diode rectifier 21, and the starter operation power supply path 29 b (see FIG. 1) that connects the second inverter 24 to the generator 20 is omitted.

  In the aspect of FIG. 9, the AC / DC converter 60 is driven by the control unit 100 when supplying power to the generator 20. Also in this embodiment, the switching operation of the relay switch 29 is controlled by the control examples shown in FIGS. 5 and 6, so that the relay switch 29 is deteriorated during the switching operation of the relay switch 29 during regeneration. It can be reduced as much as possible.

  It goes without saying that various modifications can be made within the scope of the claims of the present invention.

1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. It is a wiring diagram which shows the principal part of the hybrid vehicle. It is a block diagram which shows the control apparatus of the hybrid vehicle shown in FIG. It is a characteristic view of an inverter. It is a flowchart which shows the example of control of the regeneration operation | movement which concerns on this embodiment. It is a flowchart which shows the example of control of the regeneration operation | movement which concerns on this embodiment. It is a timing chart which shows the rise characteristic of the path voltage by the step-down operation stop. It is a timing chart which shows the rise characteristic of the path voltage by voltage step-up operation. It is a schematic block diagram of the hybrid vehicle which concerns on another embodiment of this invention.

Explanation of symbols

10 Engine 20 Generator 22 DC bus line (an example of a power supply path)
23 1st inverter 24 2nd inverter 25 Motor 29 Relay switch 30 Power supply device 31 DC-DC converter (an example of boosting means)
32 Battery 100 Control unit 101 Operating state determination unit 110 Combustion control unit 111 Relay control unit 112 Battery control unit (an example of boosting means)
113 Inverter control unit C1 Capacitor Ib Battery current Imr Reference current Ire Regenerative current Nm Motor rotation speed SW1 Generator output current sensor SW2 Generator rotation speed sensor SW3 Bus line voltage sensor SW4 Battery current sensor SW5 Battery voltage sensor SW6 Vehicle speed sensor SW7 Accelerator opening sensor SW8 Brake sensor SW11 Motor rotation speed sensor SW12 Motor voltage sensor Vb Battery voltage Vdc Path voltage Vm Motor voltage Vst Determination voltage

Claims (4)

A generator driven by an engine to generate alternating current;
A motor that drives the vehicle and also functions as a generator for regeneration when the vehicle decelerates;
A rectifier for rectifying the alternating current generated by the generator;
A first inverter connected to a power supply path between the rectifier and the motor and converting a direct current in the power supply path into an alternating current;
A second inverter connected to the power supply path in parallel with the first inverter;
A relay switch provided between the second inverter and the motor and capable of disconnecting the second inverter from the motor;
A hybrid vehicle control device comprising: a battery connected to the power supply path;
Power supply path voltage detecting means for detecting the voltage of the power supply path as a path voltage;
Motor voltage detecting means for detecting the voltage of the motor as a motor voltage;
Current calculating means for calculating a current to be passed through both inverters;
When the current calculated by the current calculation means is smaller than a predetermined reference current, either one of the first and second inverters is operated, and the current calculated by the current calculation means becomes the reference current. When compared with the inverter control unit that operates both,
When the second inverter is turned off during the regenerative operation of the motor and the path voltage is lower than the motor voltage, the boosting means boosts the power feeding path until the path voltage becomes equal to or higher than the motor voltage. When,
A relay control unit that turns off the relay switch when the path voltage is equal to or higher than the motor voltage when the second inverter is turned off during the regenerative operation of the motor. A control device for a hybrid vehicle. In the hybrid vehicle control device according to claim 1,
The vehicle includes a switching circuit that is interposed between the battery and the power feeding path and adjusts the level of a direct current,
The step-up means causes the motor to perform a regenerative operation of the battery by causing the switching circuit to perform a step-down operation, and the second inverter is turned off during the regenerative operation of the motor, and the path voltage is A control apparatus for a hybrid vehicle, comprising: a switching circuit control unit that stops a step-down operation of the switching circuit when the motor voltage is lower than the motor voltage. The control apparatus for a hybrid vehicle according to claim 2,
When the second inverter is turned off during the regenerative operation of the motor and the path voltage is lower than the motor voltage, the switching circuit control unit determines a difference between the path voltage and the motor voltage. When the voltage is less than a predetermined determination voltage, the step-down operation is stopped, and when the difference between the path voltage and the motor voltage is equal to or higher than the determination voltage, the switching circuit is boosted. Control device for hybrid vehicle. In the hybrid vehicle control device according to claim 3,
A control device for a hybrid vehicle, wherein a capacitor is connected to the power supply path.

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