JP2007191011A - Vehicle controller for protection of component of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for decelerating a vehicle for preventing IPM and capacitor breakage due to counter-electromotive force from a motor generator when an inverter becomes a gate cutoff state during high speed traveling. <P>SOLUTION: A hybrid controller is provided with a gate cutoff state acquiring means for acquiring each gate cutoff state of two inverters, an inverter gate cutoff state determining means for judging whether or not both of the two inverters are in gate cutoff prohibited states, a vehicle traveling state acquiring means, a vehicle traveling state determining means for determining whether or not IPM and capacitor breakage due to counter-electromotive force from the motor generator will occur, a master cylinder command pressure acquiring means for acquiring a master cylinder pressure command value, and a vehicle braking means for carrying out braking of the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle control device for protecting parts when an inverter gate of a hybrid vehicle is shut off.

  The hybrid system for vehicles refers to a vehicle that travels by combining two types of power sources, that is, an engine and an electric motor. This hybrid system for vehicles uses a series hybrid system in which a generator is driven by an engine, and a motor drives wheels by the generated power, and a method in which the engine and motor drive wheels, and two driving forces are applied depending on the situation. There are parallel hybrids that can be used in series and series / parallel hybrids that combine the features of both. Series / Parallel Hybrid distributes engine power by the power distribution mechanism, directly drives the wheel, and the other uses it for power generation to control the usage rate according to the running state and drive the motor with the generated power. The motor usage rate is higher than that of the parallel system. A motor generator having both functions is used for the generator and the motor. However, in the following explanation, the first motor generator (generator) is mainly used for the function of the generator, and the function of the motor is mainly used. What is played is represented as a second motor generator (motor).

  As shown in FIG. 5, the hybrid drive apparatus 1 used in such a series / parallel hybrid system includes a power distribution mechanism 20, a first motor generator 16 (generator), a second motor generator 22 (motor), and It is composed of speed reducers 30, 32 and the like. Power from the engine is divided into two by the power distribution mechanism 20, one of its output shafts is connected to the second motor generator 22 (motor) and wheels, and the other is connected to the first motor generator 16 (generator). The power of is transmitted to the wheel by two paths, mechanical and electrical. Since the rotation speed of the engine 12 and the rotation speeds of the first motor generator 16 (generator) and the second motor generator 22 (motor) (proportional to the vehicle speed) can be increased and decreased steplessly, A transmission such as a gasoline engine car is not provided (see, for example, Patent Document 1).

  The power distribution mechanism 20 is constituted by planetary gears (planetary gears), and distributes the torque of the engine 12 to the output shaft 19 and the first motor generator (generator) at the ratio of each component gear. The rotating shaft of the planetary carrier 20c inside the gear mechanism is connected to the engine 12 via a damper device 14 that absorbs rotational fluctuations, and transmits power to the outer ring gear 20r and the inner sun gear 20s through the pinion gear. The sun gear rotating shaft 24 is connected to the first motor generator (generator), and the rotating shaft 18 of the ring gear 20 r is directly connected to the second motor generator 22 (motor) and the output shaft 19. Thus, the rotation of the ring gear 22r by the second motor generator 22 (motor) drives the wheels 58 via the drive gear device 25 constituted by the reduction gear 26, the reduction gear 30, and the differential device 34. ing.

  On the other hand, in order to drive the motor generator by the power storage device or to charge the power storage device by the motor generator, the hybrid vehicle is provided with a power supply device as shown in FIG. The power supply device includes inverters 36 and 37, a power storage device 40, a DC / DC converter 39, and capacitors 35 and 38 for driving the first motor generator 16 (generator) and the second motor generator 22 (motor). is doing. The two inverters are connected to each other by two connection lines, and a capacitor 35 is provided between the two connection lines. A DC / DC converter 39 is connected to these two connection lines, and a capacitor 38 and a power storage device 40 are connected in parallel to the DC / DC converter 39 (see, for example, Patent Document 2).

  The flow of power and electric power when such a hybrid vehicle is traveling will be described with reference to FIGS. In the figure, the power flow is indicated by black arrows, and the power flow is indicated by hatched arrows. During normal running, the power of the engine 12 is distributed to the output to the first motor generator (generator) and the output shaft 19 by the power distribution mechanism 20 as shown in FIG. The output distributed to the output shaft 19 drives the axle 33 and the wheels 58 via the drive gear device 25 to drive the vehicle. On the other hand, the power distributed to the first motor generator 16 (generator) by the power distribution mechanism 20 is converted into electric energy by the first motor generator 16 (generator). The converted electric energy is once converted into direct current by the inverter 36 for the first motor generator, and then input to the inverter 37 for the second motor generator. The second motor generator inverter 37 converts this DC power into a frequency required for a predetermined rotational speed and supplies it to the second motor generator 22. At this time, when the electric power from the first motor generator 16 is less than the required electric power of the second motor generator 22, the insufficient electric power is supplied from the power storage device 40. Conversely, when the electric power is excessive, the excessive power is supplied to the power storage device 40. Charged. The second motor generator 22 is directly connected to the ring gear 22r shown in FIG. 5, and the output is transmitted to the output shaft 19 via the ring gear 22r. As described above, the output shaft 19 receives the direct driving force from the engine 12 and the output converted into the electrical output at one end by the first motor generator 16 and the inverter 36 from the inverter 37 and the second motor generator 22, and the drive gear device. The vehicle is driven by 25. In such a hybrid vehicle, the drive circuit may be destroyed by an induced voltage generated in the motor generator. As a countermeasure, an upper limit of the motor rotation speed is set based on the breakdown voltage of the drive circuit, and the upper limit is exceeded. A method for controlling the rotation of the motor so as not to occur is proposed (for example, see Patent Document 3).

JP-A-9-170533 JP 2004-112883 A JP 2005-45927 A

  In the series / parallel hybrid system vehicle including the hybrid drive device 1 including the power distribution mechanism 20, the first motor generator 16 (generator), the second motor generator 22 (motor), the drive gear device 25, and the like described above, When an overvoltage of the inverters 36 and 37 occurs for some reason during steady running, the inverter gate is shut off for protection of the inverters 36 and 37, the driving torque is set to zero, and the vehicle is allowed to run for a certain period of time, There is an advantage control that returns the inverter to a normal state after the voltage drops.

  In the power supply device having such a configuration, when one inverter is shut off by shutting off the gate of the other inverter, if the other inverter is continuously driven, DC power is rapidly accumulated in the capacitor 35 and the both ends of the capacitor 35 are When the voltage Vm suddenly rises or falls, the switching loss in the inverter increases and the life is shortened, or a large current flows to the capacitor 35 side through the diode of the DC / DC converter 39 and the DC / DC converter 39 becomes large. Problems such as a reduction in life due to the influence of current occur. For this reason, both inverters 36 and 37 are simultaneously gate-blocked to protect the inverter. Then, both inverters are in a state where the gate is shut off and do not function at all.

  FIG. 6B shows a state in which the hybrid vehicle is in an advantage control in which the vehicle is traveling in inertia with the inverter overvoltage during driving and the drive torque being zero when the gate is cut off. In this case, the engine 12 does not output a vehicle drive output in order to cause the vehicle to travel by inertia. Then, the first motor generator 16 loses input from the engine 12 and stops the inverter 36 so that the electric output is lost, and the output from the second motor generator 22 to the output shaft 19 becomes zero. However, the vehicle is traveling inertially at a certain speed, and the second motor generator 22 continues to rotate by inertial traveling of the vehicle because the rotating shaft 18 is directly connected to the output shaft 19 as shown in FIG. It becomes. Then, the second motor generator 22 generates a counter electromotive force toward the inverter 37. Since the inverter 37 is shut off due to the gate being shut off, the counter electromotive force cannot be stored in the power storage device 40 via the inverter 37 and is thus discharged from the discharge resistor 42 to the outside as resistance heat. Since the magnitude of the back electromotive force from the second motor generator 22 is an inertia running state, the speed of the vehicle does not change much before and after the inverter gate is shut off. Therefore, the first motor generator 16 before the inverter gate is shut off. To approximately the same magnitude as the electric power input to the second motor generator 22 via the inverter. When the speed of the vehicle is high, this power also increases, so that the back electromotive force from the second motor generator 22 when entering the inertial traveling also increases, and the power cannot be consumed by the discharge resistor 42. . Then, this excess power is stored in the capacitor 35 and becomes a high voltage, which is applied to the inverters 36 and 37. The inverters 36 and 37 are overvoltaged and the inverter power module (IPM) is damaged, or the capacitors 35 and 38 are damaged. There was a problem to do.

  Accordingly, an object of the present invention is to prevent damage to the capacitor and the inverter power module (IPM) due to the counter electromotive force from the motor generator even when the inverter is shut off during high-speed traveling.

  An object of the present invention is to provide a power distribution mechanism that distributes power between an engine and two motor generators, two inverters provided corresponding to the two motor generators, and inverter control that controls the two inverters, respectively. A hybrid control device for controlling travel of a hybrid vehicle comprising: an inverter gate cutoff state acquisition unit that acquires a respective gate cutoff state of each inverter; and an inverter acquired by the inverter gate cutoff state acquisition unit Inverter gate cutoff state determination means for determining whether or not both inverters are gate cutoff based on the gate cutoff state, vehicle travel state acquisition means, and vehicle travel acquired by the vehicle travel state acquisition means In the state both of the two inverter circuits A vehicle travel state determination unit that determines whether or not excessive back electromotive force is generated due to the gate being shut off, and a master that acquires a master cylinder command pressure for braking the vehicle based on a result of the vehicle travel state determination unit This can be solved by having cylinder command pressure acquisition means and vehicle braking means for braking the vehicle based on the master cylinder command pressure. Further, the master cylinder command pressure acquisition means may be a means for acquiring from a master cylinder command pressure curve in which the master cylinder command pressure increases as the vehicle speed increases.

  The present invention has an effect of preventing damage to a capacitor and an inverter power module (IPM) due to a counter electromotive force from a motor generator when the inverter is shut off during high-speed traveling.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to FIGS. FIG. 1 shows the configuration of the present invention. The hybrid drive device 1 similar to that described in the background art includes an engine 12, a power distribution mechanism 20, a first motor generator 16 (generator), a second motor generator 22 (motor), a drive gear device 25, and the like. A driving inverter 36 is connected to the first motor generator 16 (generator). Similarly, a drive inverter 37 is connected to the second motor generator 22 (motor). These two inverter circuits are connected to each other by two electric wires, and a capacitor 35 is provided in the middle of the connection line, and DC power is supplied to the two connection lines from the power storage device 40 via the DC / DC converter 39. Has been.

  The inverters 36 and 37 are controlled by the inverter control circuit 11 so that the rotation speed and torque of each motor generator become command values from the hybrid control device 10. Each of the inverters 36 and 37 outputs a signal indicating whether or not the driving state is normal to the inverter control circuit 11. When an overvoltage occurs in the inverter 36 or 37, the inverter control circuit 11 outputs a gate cutoff command to each of the inverters 36 and 37, shuts off the gate of each inverter and puts it into a stopped state.

  The inverter control circuit 11 receives a control command value signal such as the rotation speed and torque for controlling each inverter from the hybrid control device 10, and the inverter control circuit 11 determines whether each inverter is in a normal state or a gate cutoff state. The status signal shown is output to the hybrid control device 10.

  On the other hand, the output of the hybrid drive device 1 is transmitted to the differential device 34 via the reduction gear 26 and the speed reducers 30 and 32, and is transmitted to the wheels 58 via the axle 33 connected to the differential device 34. Drive. The wheel 58 is provided with a brake device 57 including a brake pad and a brake disk for stopping the rotation. The brake device 57 is connected to the master cylinder 52 for driving the device. The brake pad 57 is pressed against the brake disk by the hydraulic pressure of the master cylinder 52 to brake the wheels 58 and decelerate the vehicle. The drive hydraulic pressure of the master cylinder 52 is controlled by the hydraulic control device 50, and a hydraulic pressure command signal is input from the hybrid control device 1 to the hydraulic control device 50. Further, the vehicle is provided with a speed detector 54 that measures the vehicle speed from the number of rotations of the wheel, and a signal from the speed detector 54 is input to the hybrid control device 10. In the storage device 13, a master cylinder command pressure curve (FIG. 3) that defines the relationship between the vehicle speed and the pressure command value of the master cylinder 52 is stored as data.

  The hybrid control device 10 includes an inverter gate cutoff state acquisition unit 101 that acquires a gate cutoff state signal of each inverter from the inverter control circuit 11, an inverter gate cutoff state determination unit 102 that determines whether the inverter is in a gate cutoff state, and a running state of the vehicle. Vehicle running state obtaining means 103 for obtaining vehicle running state, vehicle running state judging means 104 for judging the running state of the vehicle, master cylinder command pressure obtaining means 105 for obtaining the hydraulic command value of the master cylinder 52 of the brake device 57 from the storage device 13, and Vehicle braking means 106 for outputting a vehicle braking command.

Next, the operation of the hybrid control device of the present invention will be described with reference to FIGS.
(1) When the hybrid vehicle is running at a normal high speed, the back electromotive force Wr (generated power) from the first motor generator 16 is input to the inverter as a back electromotive force (FIG. 4A). t ₁ or earlier). Each inverter 36, 37 operates normally and no abnormal signal is output.
(2) When an overvoltage is applied to one of the inverters 36 and 37, an overvoltage signal is output from the inverter to the inverter control circuit 11.
(3) The inverter control circuit 11 shuts off the gates of both inverters due to overvoltage (FIG. 4 (b) f to g) and outputs a signal indicating that each inverter is in a gate cut-off state to the hybrid control device 10. This signal is acquired by the hybrid control apparatus 10 by the inverter gate cutoff state acquisition means 101 of the hybrid control apparatus 10 (FIG. 2, step S11). At this time, the counter electromotive force from the first motor generator 16 is eliminated, t ₁ subsequent to the counter electromotive force from the second motor-generator 22 comes depends on the inverter (Fig. 4 (a))). Then, a part of the electric power below Wd in FIG. 4 (the hatched portion at the lower right) is released by the discharge resistor 42, but the remaining portion is not released by the discharge resistor 42 and is stored in the capacitor 35, A high voltage is applied to the inverters 36 and 37 (b to c in FIG. 4A).
(4) Based on the signal acquired by the inverter gate cutoff state acquisition unit 101, the hybrid control apparatus 10 determines whether both inverters are in the gate cutoff state by the inverter gate cutoff state determination unit 102. (FIG. 2, step S12).
(5) If both inverters are not in the gate cutoff state, an inverter gate cutoff state signal is acquired again (FIG. 2, step S21).
(6) When it is determined that both inverters are in the gate cut-off state, the hybrid controller 10 uses the vehicle running state acquisition unit 103 to calculate the absolute value of the vehicle speed based on the signal from the speed detector 54. Is acquired as the running state (FIG. 2, step S13).
(7) The hybrid control device 10 compares the acquired absolute value of the vehicle speed with the predetermined speed value Vo of FIG. 4D by the vehicle running state determination means 104, and the absolute value of the vehicle speed is greater than the predetermined speed value Vo. If it is larger, it is determined that the capacitor or the inverter power module (IPM) is damaged due to the counter electromotive force from the motor generator. When the absolute value of the vehicle speed is smaller than the predetermined speed value Vo, it is determined that the capacitor and the inverter power module (IPM) are not damaged by the counter electromotive force from the motor generator, and the vehicle running state is acquired again ( FIG. 2, steps S14 and S23).
(8) When it is determined that damage will occur, the hybrid controller 10 causes the master cylinder command pressure acquisition means 105 to store the hydraulic command value of the master cylinder 52 based on the vehicle speed acquired by the vehicle running state determination means 104 in the storage device 13. Obtained from the master cylinder command pressure curve (FIG. 2, step S15). As shown in FIG. 3, the master cylinder command pressure curve is a curve in which initial values (w and x in FIG. 3) are set when a predetermined speed value Vo is reached, and the pressure increases as the speed increases, and increases as the speed increases. Braking is applied (from x to y in FIG. 3). The master cylinder pressure command value becomes constant when the upper limit value of the master cylinder 52 is reached (y and z in FIG. 3).
(9) The vehicle braking means 106 of the hybrid control device 10 outputs the acquired master cylinder pressure command value to the hydraulic control device 50 as the pressure command value of the master cylinder 52 of the hydraulic brake for vehicle braking (FIG. 2, step). S16, FIG. 4 (c) k to l).
(10) The hydraulic control device 50 increases the hydraulic master cylinder pressure to the command value, thereby driving the brake device 57 to decelerate the vehicle (FIG. 4 (c) 1 to m, (d) q to r). .
(11) As the vehicle speed is reduced, the back electromotive force from the second motor generator is also reduced (FIGS. 4A to 4C).
(12) When the vehicle speed is equal to or lower than the predetermined speed value Vo and the capacitor and the inverter power module (IPM) are not damaged due to the back electromotive force from the motor generator, the deceleration command value decreases and the braking operation is finished. . (FIG. 4 (c) m to n)

  As described above, the hybrid control device according to the present invention can prevent the capacitor and the inverter power module (IPM) from being damaged due to the counter electromotive force from the motor generator even when the inverter is shut off during high-speed traveling. There is an effect.

It is a block diagram of embodiment of this invention. It is embodiment flowchart of this invention. It is a master cylinder command pressure value curve of an embodiment of the present invention. It is operation | movement explanatory drawing of embodiment of this invention. It is explanatory drawing of a hybrid drive mechanism apparatus. It is a figure which shows the motive power and electric power flow of a hybrid vehicle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Hybrid drive device, 10 Hybrid control device, 11 Inverter control circuit, 12 Engine, 13 Storage device, 14 Damper device, 16 1st motor generator, 18 Rotating shaft, 19 Output shaft, 20 Power distribution mechanism, 20c Carrier, 20s Sun gear , 20c Planetary carrier, 20r, 22r Ring gear, 22 Second motor generator, 24 Rotating shaft, 25 Drive gear device, 26 Reduction gear, 30, 32 Reducer, 33 Axle, 34 Differential device, 35 Condenser, 36, 37 Inverter, 38 capacitor, 39 DC / DC converter, 40 power storage device, 42 discharge resistance, 50 hydraulic control device, 52 master cylinder, 54 speed detector, 57 brake device, 58 wheel, 101 inverter gate cutoff state acquisition means, 1 2 Inverter gate cut-off state determination means, 103 Vehicle running state acquisition means, 104 Vehicle running state determination means, 105 Master cylinder command pressure acquisition means, 106 Vehicle braking means, S10 to S23 steps, Vo speed value, Vm voltage, Wr, Wd Power.

Claims (2)

A power distribution mechanism that distributes power between the engine and the two motor generators;
Two inverters respectively provided corresponding to the two motor generators;
An inverter control circuit for controlling each of the two inverters;
A hybrid control device for controlling the traveling of a hybrid vehicle comprising:
Inverter gate cutoff state acquisition means for acquiring each gate cutoff state of each inverter;
An inverter gate cutoff state determination means for determining whether or not both of the two inverters are gate cutoff based on the gate cutoff state of the inverter acquired by the inverter gate cutoff state acquisition means;
Vehicle running state acquisition means;
Vehicle traveling state determination means for determining whether or not excessive back electromotive force is generated due to both of the two inverter circuits being gated in the vehicle traveling state acquired by the vehicle traveling state acquisition unit;
Master cylinder command pressure acquisition means for acquiring a master cylinder command pressure for braking the vehicle based on the result of the vehicle running state determination means;
Vehicle braking means for braking the vehicle based on the master cylinder command pressure;
A hybrid control device comprising: The master cylinder command pressure obtaining means is a means for obtaining from a master cylinder command pressure curve in which the master cylinder command pressure increases as the vehicle speed increases.
The hybrid control device according to claim 1.

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