JP2009055784A - Vehicle controlling apparatus, vehicle controlling method and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve highly efficient driving utilizing regenerative power and to obtain a maintenance-reduced, inexpensive vehicle controlling apparatus and vehicle. <P>SOLUTION: The apparatus is provided with a motor 1, an alternating current generator 2 to be driven by the motor 1, a first power converter 3a to convert alternating current power output from the alternating current generator 2 into direct current power, a second power converter 6 to convert the direct current power into the alternating current power having a variable frequency, and an alternating-current electric motor 7 to be driven by the second power converter 6. Furthermore, the apparatus has a resistor 401 and a switching means 402 and is provided with a break chopper 4 to be connected to the direct current side of the second power converter 6 and a storage battery 5 to be connected to the direct current side of the second power converter 6. The regenerative power acquired from the alternating-current electric motor 7 is stored or consumed by the motor 1, the break chopper 4 and the storage battery 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle control device suitable for braking a vehicle, a vehicle including the vehicle control device, and a vehicle control method.

  In a generator built-in type vehicle composed of an engine, a generator, a rectifier, an inverter, and an electric motor, a braking method using a brake device and a method using an electric brake (regenerative brake) using the electric motor as a generator at the time of deceleration There is. In the case of an electric brake, by providing an energy storage device such as a capacitor, the generated power (regenerative power) can be stored and energy loss can be reduced. This makes it possible to effectively use the regenerative energy obtained during braking.

Patent Document 1 discloses an example of a vehicle that drives a train with high efficiency by storing regenerative energy generated when the vehicle is braked by a regenerative brake in a power storage device such as a battery and using it effectively.
JP 2003-134604 A

  However, in the method of Patent Document 1, since the regenerative energy cannot be processed when the amount of power stored in the capacitor exceeds the upper limit, it is necessary to reduce the regenerative braking force and brake by the mechanical brake. Since the mechanical brake is a braking means that uses a frictional force, the brake shoe or the like is worn. Therefore, when used frequently, there has been a problem that the replacement cycle is shortened and the maintenance cost is increased. On the other hand, when a capacitor having a capacity sufficient to store regenerative energy is mounted, problems such as an increase in cost and weight of the capacitor have occurred.

  An object of the present invention is to realize a high-efficiency operation using regenerative energy and a low-cost and low-cost vehicle control device and vehicle.

A vehicle control apparatus according to the present invention includes a prime mover, an alternating current generator driven by the prime mover, a first power converter that converts alternating current power output from the alternating current generator into direct current power, and direct current power with variable frequency alternating current. A second power converter for converting into electric power and an AC motor driven by the second power converter are provided. Furthermore, it has a resistor and switching means, and includes a brake chopper connected to the DC side of the second power converter, and a capacitor connected to the DC side of the second power converter. Then, the regenerative power from the AC motor is stored or consumed by the prime mover, the brake chopper, and the capacitor .

Moreover, the vehicle by this invention mounts the said vehicle control apparatus. A vehicle control method according to the present invention is a method for controlling a vehicle by the vehicle control device.

According to the present invention, regenerative energy generated at the time of braking is stored in a capacitor and can be effectively used by consuming it when power is insufficient during acceleration or stopping, thereby realizing high-efficiency driving. Further, even when the amount of electricity stored in the capacitor exceeds the upper limit, regenerative energy can be consumed by the prime mover and the brake chopper, so that there is no need to use a mechanical brake. For this reason, wear of the brake shoes and the like can be prevented, and maintenance can be saved. Furthermore, since it is not necessary to increase the capacity of the capacitor, a low-cost and lightweight vehicle control device and vehicle can be realized.

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

  First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an example of the entire configuration according to the first embodiment of the present invention. In this example, the engine 1, the generator 2 connected to the engine 1, the rectifier 3 that converts the generated power into direct current, and the brake chopper 4, the capacitor 5, and the inverter 6 are connected in parallel to the direct current side of the rectifier 3. Configure. The brake chopper 4 is constituted by a series circuit of a resistor 401 and a switching element 402. The battery 5 is a chargeable / dischargeable battery such as a lithium ion battery. An AC motor 7 is connected to the inverter 6, and by driving the AC motor 7, the wheels 8 are driven and the vehicle 9 is caused to travel. The wheel 8 is provided with a mechanical brake 10, and the AC motor 7 is provided with a speed detector 11. An inverter control unit 101 that controls the inverter 6, a mechanical brake control unit 103 that controls the mechanical brake 10, a power storage amount control unit 105 that controls the power storage amount of the battery 5, and a brake chopper control unit 107 that controls the brake chopper 4 Provide and control each device.

  In this example, when the vehicle is accelerated, the generator 2 is driven by the engine 1, and the generated power is converted into direct current by the rectifier 3. The DC power converted by the rectifier 3 is transmitted to the inverter 6, and the inverter 6 converts the DC to AC and drives the AC motor 7, thereby driving the wheels 8 and running the vehicle 9. During braking, braking is performed by operating the AC motor 7 as a generator. Electric power generated by the AC motor 7 is input to the inverter 6, converted into DC power by the inverter 6, and stored in the battery 5.

  Next, processing of each control unit will be described. First, the process of the inverter control unit 101 will be described. The inverter control unit 101 inputs the speed Vt of the AC motor 7 detected by the speed detector 11 and the first torque command Tref, and outputs the second torque command T *. The first torque command Tref is a command output from a host controller according to the notch signal and speed of the cab.

  FIG. 2 shows the characteristics of the upper limit value of the second torque command T *. The inverter control unit 101 obtains the upper limit value of the second torque command T * using the speed Vt of the AC motor 7 and the characteristics shown in FIG. 2, and the first torque is determined based on the obtained upper limit value of the second torque command. The command Tref is limited, and the value is output as the second torque command T *. The inverter 6 converts the direct current into alternating current of variable frequency and variable voltage so as to drive the AC motor 7 so that the second torque command T * output from the inverter control unit 101 matches the output torque of the AC motor 7. .

  Next, processing of the mechanical brake control unit 103 will be described. The mechanical brake control unit 103 is configured to input the output of the subtracter 102. The subtracter 102 inputs the first torque command Tref output from the host controller and the second torque command T * output from the inverter control unit 101, and the second torque command Tref is output from the first torque command Tref. The torque deviation ΔT is obtained by subtracting the command T *. The mechanical brake control unit 103 performs control so that the torque deviation ΔT output from the subtractor 102 matches the braking force of the mechanical brake 10.

  Next, processing of the charged amount control unit 105 and the brake chopper control unit 107 will be described. First, the storage battery observation unit 104 inputs the storage battery voltage Vb and the storage battery current Ib of the storage battery 5, and estimates the storage amount SOC. The storage amount control unit 105 receives the storage amount SOC output from the storage battery observation unit 104, and outputs a storage device current command Ib * based on the storage amount SOC. FIG. 3 shows a relationship between the storage amount SOC and the storage battery current command Ib * output from the storage amount control unit 105. When the storage amount SOC is less than or equal to the upper limit of the storage amount, the capacitor current command Ib * is the rated current of the storage device, and when the storage amount SOC exceeds the upper limit of the storage amount, the capacitor current command Ib * is zero. The battery current command Ib * output from the power storage amount control unit 105 is input to the subtractor 106. The subtractor 106 inputs the capacitor current command Ib * and the capacitor current Ib, subtracts the capacitor current Ib from the capacitor current command Ib *, and outputs a capacitor current deviation ΔIb. The brake chopper controller 107 receives the capacitor current deviation ΔIb output from the subtractor 106, and calculates the conduction rate VBr based on the equation (1).

VBr = − (Kp + Ki / s) ΔIb (1)
Here, Kp and Ki are control gains, and s is a differential operator.

  The brake chopper 4 receives the conduction rate command VBr output from the brake chopper control unit 107, performs switching of the switching element 402 based on the conduction rate VBr, and consumes power by the resistor 401. In this way, by controlling the storage amount control unit 105 and the brake chopper control unit 107 in conjunction with each other, the brake chopper 4 can consume the surplus regenerative power so as not to exceed the storage amount upper limit of the storage battery 5. it can.

  Next, the operation of this example will be described. FIG. 4 shows an example of the operation during braking according to the first embodiment of the present invention. 4, the horizontal axis represents time, the vertical axis represents the speed of the vehicle 9 from the top, the first torque command Tref, the second torque command T *, the braking force of the mechanical brake, the power of the regenerative brake, the power of the mechanical brake, The capacitor current Ib, the capacitor current command Ib *, the brake chopper conduction rate VBr, and the storage amount SOC.

  Initially, the vehicle 9 is traveling, and the storage amount SOC is lower than the upper limit of the storage amount. At time T1, the first torque command Tref rises and braking of the vehicle 9 is started. When the first torque command Tref rises, the second torque command T * also rises, and the decrease in the kinetic energy of the vehicle 9 due to regenerative braking becomes regenerative brake power and flows into the capacitor 5 via the inverter 6, so that the capacitor current Ib increases, and the storage amount SOC increases.

  When the first brake command Tref exceeds the upper limit value of the second torque command T * at time T2, the second torque command T * is limited by the upper limit value. At this time, since the torque deviation ΔT increases, a mechanical brake braking force is generated. This is because braking by the regenerative brake is limited by the upper limit value of the second torque command T *, so that the braking force is insufficient in the regenerative brake, and the mechanical brake is operated to supplement it. The first torque command Tref becomes constant at time T3, and then the second torque command T * increases as the speed decreases. As a result, the mechanical brake braking force decreases, and the mechanical brake braking force becomes zero at time T4.

  When the charged amount SOC reaches the charged amount upper limit at time T5, the capacitor current command Ib * becomes 0 due to the characteristics of the charged amount control unit 105. On the other hand, since the battery current Ib does not decrease immediately, the battery current deviation ΔIb becomes negative, and the conduction rate VBr calculated by the above equation (1) increases. In the brake chopper 4, a current flows based on the conduction rate VBr, and the regenerative brake power is consumed by the resistor 401. Along with this, the capacitor current Ib decreases and becomes zero. FIG. 5 shows an enlarged graph of the state near the time T5 of the capacitor current Ib and the capacitor current command Ib *. As described above, after the battery current command Ib * becomes 0, the current flows to the brake chopper 4 side, whereby the battery current Ib decreases.

  However, in the case of a configuration without a conventional brake chopper, it is necessary to reduce the second torque command T * and suppress the regenerative brake power in order to suppress charging of the battery 5. As a result, a mechanical brake braking force for compensating for the insufficient braking force of the regenerative brake is generated, and the consumption of the mechanical brake increases.

  Thus, in this example, even when the charged amount SOC of the battery 5 reaches the charged amount upper limit, braking can be performed without using the mechanical brake, and consumption of the mechanical brake can be suppressed. Further, when the conduction rate VBr increases, the battery current Ib decreases and is controlled to coincide with the battery current command Ib *. Therefore, the charged amount SOC does not exceed the charged amount upper limit.

  Thereafter, when the regenerative brake power decreases with the decrease in speed, the conduction rate VBr decreases so that the capacitor current Ib matches the capacitor current command Ib *, and the current of the brake chopper 4 also decreases. For this reason, the electric power stored in the capacitor is not consumed by the brake chopper 4. When the vehicle 9 stops at time T6, the first torque command Tref becomes 0 and the regenerative brake power becomes 0, so the conduction rate VBr also becomes 0.

  It should be noted that the characteristic of the storage amount control unit 105 is a characteristic that gradually decreases the storage battery current command Ib * with respect to the storage amount SOC so that the storage battery current command Ib * becomes 0 at the storage amount upper limit as shown in FIG. It may be. In this case, since the storage battery current command Ib * decreases and the storage battery current Ib also decreases from a state in which the storage charge SOC is smaller than the storage charge upper limit, the storage charge SOC does not easily exceed the storage charge upper limit.

  As described above, according to the first embodiment of the present invention, the regenerative energy can be effectively used by storing the regenerative energy by the regenerative brake in the battery 5. Even when regenerative energy exceeding the upper limit of the amount of electricity stored in the battery 5 is generated, regenerative power can be processed by a low-cost brake chopper, so there is no need to use mechanical brakes and maintenance is reduced. It becomes possible to do.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 shows an example of the entire configuration according to the second embodiment. The same components as those in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 7, the converter 3a is connected to the generator 2, and the converter control part 201 which controls the converter 3a is provided. A brake chopper 4, a capacitor 5, and an inverter 6 are configured to be connected in parallel to the DC side of the converter 3a.

  Converter control unit 201 controls converter 3a by operating converter output command P * so that power flows from the DC side to the AC side when storage amount SOC exceeds the upper limit of storage amount in the braking state. Based on a converter output command P *, which is the output of the converter control unit 201, the converter 3a bi-directionally converts the variable voltage variable frequency AC on the generator 2 side and the DC on the inverter 6 side. That is, when the charged amount SOC exceeds the charged amount upper limit in the braking state, the generator 2 is controlled to convert electrical energy into mechanical energy and is braked by the engine brake. At this time, the regenerative energy generated by the AC motor 7 is consumed by the engine 1 via the inverter 6, the converter 3 a, and the generator 2.

  Next, the operation according to the second embodiment of the present invention will be described. FIG. 8 shows an example of the operation according to the second embodiment of the present invention. The description of the same part as the example of the operation shown in FIG. 4 described in the first embodiment is omitted. The sixth graph from the top in FIG. 4 shows the mechanical brake power, but FIG. 8 shows the converter output command P *. Until time T5, converter output command P * is 0, and the operation of other parts is the same as the operation shown in FIG.

  When the charged amount SOC reaches the charged amount upper limit at time T5, the capacitor current command Ib * becomes 0 and the converter output command P * increases. In addition, the brake chopper conduction rate command VBr also increases due to the capacitor current deviation ΔIb that is the difference between the capacitor current command Ib * and the capacitor current Ib. However, in this example, since a part of the regenerative brake power is consumed by the engine 1 via the converter 3a and the generator 2, the capacitor current Ib is reduced as compared with the first embodiment, and the brake chopper flow The rate command VBr is also smaller than that in the first embodiment.

  Thereby, compared with 1st Embodiment, since the energy consumed with the brake chopper 4 becomes small, it is possible to make the capacity | capacitance of the brake chopper 4 small. It should be noted that the regenerative power is effectively utilized by storing the regenerative power by the regenerative brake in the battery 5, and even if regenerative energy exceeding the upper limit of the charge amount of the battery 5 is generated, the regenerative power is generated by a low-cost brake chopper. As in the first embodiment, it is possible to reduce the maintenance because it is not necessary to use a mechanical brake.

  Next, a third embodiment of the present invention will be described with reference to FIG. 9, FIG. 10, and FIG. FIG. 9 shows an example of the entire configuration according to the third embodiment. The same components as those in FIG. 1 described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In this example, a current detector 301 that detects an inverter DC current that is a DC-side current of the inverter 6 and an inverter power calculation unit 302 are provided. The inverter power calculation unit 302 calculates the inverter power Pi based on the product of the inverter DC current detected by the current detector 301 and the storage battery voltage Vb. However, when power is converted from the AC side to the DC side, the sign of the inverter power Pi is positive.

  The storage amount control unit 105a outputs the chargeable power Pb * based on the storage amount SOC output from the storage battery observation unit 104. In the first embodiment described with reference to FIG. 1, the output of the storage amount control unit 105 is the capacitor current command Ib *. However, the storage amount control unit 105a of this example outputs chargeable power Pb *. FIG. 10 shows the characteristics of the chargeable power Pb * with respect to the storage amount SOC. When the storage amount SOC is less than or equal to the upper limit of the storage amount, the chargeable power Pb * is the rated maximum charge power of the capacitor, and when the storage amount SOC exceeds the upper limit of the storage amount, the chargeable power Pb * is zero. In the subtractor 106a, the inverter power Pi output from the inverter power calculation unit 302 and the chargeable power Pb * output from the storage amount control unit 105a are input, and the chargeable power Pb * is subtracted from the inverter power Pi. , Output power deviation ΔP. The brake chopper control unit 107a inputs the power deviation ΔP from the subtractor 106a, calculates the conduction ratio VBr so that the power deviation ΔP and the power consumption of the brake chopper 4 coincide with each other, and controls the brake chopper 4.

  Next, an operation according to the third embodiment of the present invention will be described. FIG. 11 shows an example of the operation according to the third embodiment of the present invention. Note that the description of the same operation as the example of the operation illustrated in FIG. 4 described in the first embodiment is omitted. The seventh graph from the top of FIG. 4 shows the capacitor current Ib and the capacitor current command Ib *, but FIG. 11 shows the chargeable power Pb * and the inverter power Pi. The inverter power Pi is an amount obtained by subtracting the loss at the inverter 6 from the regenerative brake power. However, since the loss of the inverter 6 is smaller than the regenerative brake power, it substantially matches the regenerative brake power.

  In FIG. 11, the operation up to time T5 is the same as in FIG. When the charged amount SOC reaches the charged amount upper limit at time T5, the chargeable power Pb * becomes 0, and thus the power deviation ΔP becomes a positive value. As a result, the flow rate VBr of the brake chopper 4 is increased, and the power consumption of the brake chopper 4 is controlled to coincide with the power deviation ΔP. As a result, the difference between the inverter power Pi and the power deviation ΔP matches the chargeable power Pb *, and the amount obtained by subtracting the power consumed by the brake chopper 4 from the inverter power Pi is charged in the capacitor 5. The electric power charged to coincides with the chargeable electric power Pb * and becomes zero. As a result, the battery 5 is not charged, and the charged amount SOC is kept constant.

  That is, according to the third embodiment of the present invention, as in the first embodiment, it is possible to effectively use the regenerative power by storing the regenerative power generated by the regenerative brake in the battery 5. Even if regenerative energy exceeding the upper limit of 5 storage capacity is generated, regenerative power can be processed by a low-cost brake chopper, and maintenance can be reduced because there is no need to use mechanical brakes. It is.

  Further, the characteristic of the charged amount control unit 105a may be a characteristic that gradually decreases with respect to the charged amount SOC so that the upper limit of the charged amount becomes zero. In this case, the chargeable power Pb * decreases from the state where the storage amount SOC is smaller than the storage amount upper limit, and the power consumption in the brake chopper 4 also decreases. Therefore, the storage amount SOC does not easily exceed the storage amount upper limit. Further, the inverter power calculation unit 302 obtains the inverter power Pi from the current and voltage on the DC side of the inverter 6, but it is also possible to calculate by multiplying the current and voltage on the AC side of the inverter 6 by the efficiency of the inverter 6. It is. In this case, it is also possible to divert the detector used for controlling the AC motor 7.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 shows an example of the entire configuration according to the fourth embodiment. The same components as those of FIG. 9 described in the third embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In this example, a converter 3a is connected to the generator 2, and a current detector 303 that detects a converter DC current that is a current on the DC side of the converter 3a, a converter power calculation unit 304, and a converter control unit that controls the converter 3a. 201. The converter 3a and the converter control unit 201 are the same as those described in the second embodiment. Converter power calculation unit 304 calculates converter power Pc based on the product of converter DC current and capacitor voltage Vb. However, the sign of converter power Pc is positive when power is converted from the DC side to the AC side of converter 3a.

  In the subtractor 106b, the inverter power Pi output from the inverter power calculation unit 302, the chargeable power Pb * output from the storage amount control unit 105a, and the converter power Pc output from the converter power calculation unit 304 are input. The subtractable charge power Pb * and the converter power Pc are subtracted from the inverter power Pi to output a power deviation ΔP. The brake chopper control unit 107 a inputs the power deviation ΔP from the subtractor 106 b, calculates the conduction ratio VBr so that the power deviation ΔP and the power consumption of the brake chopper 4 coincide with each other, and controls the brake chopper 4.

  The difference between this example and the third embodiment is that a part of the inverter power Pi is consumed by the engine 1 via the converter 3 a and the generator 2. For this reason, the power charged in the battery 5 is an amount obtained by subtracting the converter power Pc and the power consumed by the brake chopper 4 from the inverter power Pi. Accordingly, when the charge amount SOC exceeds the upper limit of the charge amount, the battery 5 is charged by controlling the power consumption in the brake chopper 4 to an amount obtained by subtracting the chargeable power Pb * and the converter power Pc from the inverter power Pi. The electric power to be supplied matches the chargeable electric power Pb * and becomes zero. Thereby, as in the third embodiment, the storage amount SOC is kept constant. Moreover, the capacity | capacitance of the brake chopper 4 can be reduced similarly to 2nd Embodiment.

  Thus, according to the present invention, highly efficient operation can be realized by storing regenerative energy in a capacitor and effectively using it. Furthermore, even when the amount of electricity stored in the capacitor exceeds the upper limit, the regenerative energy can be consumed by the brake chopper, so there is no need to use a mechanical brake, and the maintenance of the mechanical brake can be saved.

It is a block diagram which shows the example of whole structure by the 1st Embodiment of this invention. It is a characteristic view which shows the characteristic example of the 2nd torque instruction | command by the 1st Embodiment of this invention. It is a characteristic view which shows the example of a characteristic of the electrical storage amount control part by the 1st Embodiment of this invention. It is explanatory drawing which shows the operation example by the 1st Embodiment of this invention. It is explanatory drawing which shows the operation example of the capacitor | condenser current and capacitor | condenser current instruction | command by the 1st Embodiment of this invention. It is a characteristic view which shows the other characteristic example of the electrical storage amount control part by the 1st Embodiment of this invention. It is a block diagram which shows the example of whole structure by the 2nd Embodiment of this invention. It is explanatory drawing which shows the operation example by the 2nd Embodiment of this invention. It is a block diagram which shows the example of whole structure by the 3rd Embodiment of this invention. It is a characteristic view which shows the example of a characteristic of the electrical storage amount control part by the 3rd Embodiment of this invention. It is explanatory drawing which shows the operation example by the 3rd Embodiment of this invention. It is a block diagram which shows the example of whole structure by the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Generator, 3 ... Rectifier, 3a ... Converter, 4 ... Brake chopper, 5 ... Accumulator, 6 ... Inverter, 7 ... AC motor, 8 ... Wheel, 9 ... Vehicle, 10 ... Mechanical brake, 11 ... Speed detector 101 ... Inverter control unit 102 ... Subtractor 103 ... Mechanical brake control unit 104 ... Capacitor observation unit 105, 105a ... Charge amount control unit 106, 106a, 106b ... Subtractor 107, 107a ... Brake chopper controller 201 ... converter controller 301 ... current detector 302 ... inverter power calculator 303 ... current detector 304 ... converter power calculator 401 ... resistor 402 ... switching element

Claims (3)

And the original motivation,
An AC generator driven by the prime mover,
A first power converter that converts AC power output from the AC generator into DC power ;
A second power converter you convert the DC power into AC power of variable frequency,
An AC motor driven by the second power converter;
Has a resistance vessels and switching means, a brake chopper that is connected to the DC side of the second power converter,
And a connection is Ru capacitor to the DC side of the second power converter,
The AC regenerative power from the motor vehicle control device you characterized in that the power storage or consumed by the motor and the brake chopper and the capacitor. And the original motivation,
An AC generator driven by the prime mover,
A first power converter that converts AC power output from the AC generator into DC power ;
A second power converter you convert the DC power into AC power of variable frequency,
The AC power from the second power converter, an alternating current motor arranged to drive the vehicle wheels,
Has a resistance vessels and switching means, a brake chopper that is connected to the DC side of the second power converter,
And a connection is Ru capacitor to the DC side of the second power converter,
Vehicle you characterized in that the regenerative power from the AC motor, power storage, or consumed in the motor and the brake chopper and the capacitor. The AC power output from the AC generator driven by the prime mover is converted to DC power by the first power converter ,
The DC power converted by the first power converter converts the AC power of variable frequency in the second power converter,
In the vehicle control method of supplying AC power converted by the second power converter to a vehicle driving AC motor,
Regenerative power from the AC motor is stored or consumed by the prime mover, a brake chopper connected to the DC side of the second power converter, and a capacitor connected to the DC side of the second power converter. A vehicle control method comprising:

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