JP7407145B2 - Vehicle power control device - Google Patents

Description

The present invention relates to a power control device for a vehicle that includes two motor generators as driving power sources.

Patent Document 1 discloses that in an electric vehicle equipped with two electric motors having a common rotational axis as driving power sources, when the vehicle is braked, the battery is in a nearly fully charged state, so each electric motor is regenerated. When it is not possible to return all the regenerated electric power obtained during operation to the battery, one of the electric motors is put into regenerative operation, and the other electric motor is put into power running operation using the regenerated electric power obtained by this regenerative operation. A power control device for an electric vehicle is disclosed.

Patent Document 2 discloses a drive device for an electric vehicle that includes two motor generators and a planetary gear mechanism that combines the power of the two motor generators, and in which the output of the planetary gear mechanism is transmitted to wheels.

Patent Document 3 discloses a graph showing the relationship between battery temperature and SOC (State of Charge) and charge/discharge allowable power of the battery.

Further, Non-Patent Document 1 discloses a graph showing the relationship between electric motor current, current phase angle, and torque.

Japanese Patent Application Publication No. 7-99704 JP 2018-100709 Publication Japanese Patent Application Publication No. 2015-120482

“Sensorless vector control of AC drive systems” edited by the Institute of Electrical Engineers of Japan, Special Committee for Research on Organizing Sensorless Vector Control, Ohmsha, 2016

As in the power control device for an electric vehicle disclosed in Patent Document 1, when braking the vehicle without charging the battery by causing one electric motor to perform power running operation and causing the other electric motor to perform regenerative operation. is unable to maintain the braking torque provided by the electric motor, and is forced to brake using the mechanical brake. The reason is shown below.

Of the two electric motors, the rotational speed of the first electric motor that is operated in regenerative mode when braking the vehicle is N1, and the rotational speed of the second electric motor that is operated in power running mode is N2. Then, assuming that the regeneration direction is positive, the torque of the first electric motor is T1, and the torque of the second electric motor is -T2. When braking a vehicle only with an electric motor without using a mechanical brake, the braking torque Tz is expressed by the following (Formula a).

Tz=T1-T2...(Formula a)

Since the first motor and the second motor have a common rotation axis, N1=N2, and therefore, the electric power Pb charged in the battery is expressed by the following (formula b).

Pb=T1N1-T2N2=(T1-T2)N1=TzN1...(Formula b)

According to the above (formula b), when the electric power Pb charged in the battery is reduced, the braking torque Tz is also reduced in conjunction with the reduction. As described above, the power control device of Patent Document 1 has a drawback in that when the electric power Pb charged in the battery is reduced, the braking torque Tz also decreases accordingly.

Further, the drive device for an electric vehicle disclosed in Patent Document 2 includes two motor generators and a planetary gear mechanism that combines the power of the two motor generators, and has a configuration in which the output of the planetary gear mechanism is transmitted to the wheels. The structure is different from that of the electric vehicle drive device disclosed in Patent Document 1, which includes two electric motors having a common rotation axis.

Therefore, the present invention provides a vehicle that is equipped with two motor generators and a planetary gear mechanism that combines the power of the two motor generators, and in which the output of the planetary gear mechanism is transmitted to the wheels. The purpose is to reduce the power charged to the battery without reducing the power.

The power control device for a vehicle according to the present invention is capable of generating power by consuming power through a power operation, and by transmitting and receiving power between two motor generators that can generate power through a regenerative operation, and the two motor generators. A power control device for a vehicle, comprising a chargeable and dischargeable battery, and a transmission mechanism that includes a planetary gear mechanism that combines the power of the two motor generators and transmits the output of the planetary gear mechanism to the wheels, When the two motor generators are driven under MTPA (Maximum Torque Per Ampere) control at a rotational speed that minimizes the mechanical loss of the transmission mechanism during braking of the vehicle, the electric power charged to the battery is transferred to the battery. If the charging power is larger than the allowable charging power of It is characterized by

The present invention enables the motor generator to drive the two motor generators at a rotation speed that increases the mechanical loss of the transmission mechanism compared to the rotation speed that minimizes the mechanical loss of the transmission mechanism when braking the vehicle. It is possible to reduce the electric power charged to the battery without reducing the braking force.

In one aspect of the vehicle power control device according to the present invention, when the two motor generators are driven by MTPA control at a rotation speed that minimizes mechanical loss of the transmission mechanism when braking the vehicle, the If the electric power charged to the battery is larger than the allowable charging electric power of the battery, the loss of the motor generator of the two motor generators that is in regenerative operation and the loss of the inverter that drives the motor generator that is in regenerative operation The motor generator during the regenerative operation may be driven under driving conditions that increase the sum of , , and more than the MTPA control.

According to this aspect, when braking the vehicle, the two motor generators are not only driven at a rotation speed that increases the mechanical loss of the transmission mechanism compared to the rotation speed that minimizes the mechanical loss of the transmission mechanism. Furthermore, by driving the motor generator during regenerative operation under driving conditions that increase the sum of the loss of the motor generator during regenerative operation and the loss of the inverter that drives the motor generator during regenerative operation than the MTPA control. , the electric power charged to the battery can be further reduced without reducing the braking force of the motor generator.

In one aspect of the vehicle power control device according to the present invention, the allowable charging power of the battery may be calculated based on the temperature and SOC of the battery.

According to this aspect, the allowable charge power of the battery can be calculated accurately, so overcharging of the battery can be avoided and the life of the battery can be extended.

The present invention provides a vehicle that includes two motor generators and a planetary gear mechanism that combines the power of the two motor generators, and in which the output of the planetary gear mechanism is transmitted to the wheels. The power charged to the battery can be reduced without being reduced.

1 is a diagram showing a configuration of a drive device of a vehicle in which a power control device according to an embodiment of the present disclosure is mounted. 1 is a diagram showing a control system of a power control device for a vehicle according to the present embodiment. 2 is a flowchart showing a control routine executed by the vehicle power control device according to the present embodiment when braking the vehicle. FIG. 3 is a diagram showing the relationship between the rotation speed of the first motor generator, the rotation speed of the second motor generator, and the magnitude of mechanical loss of the transmission mechanism. FIG. 3 is a diagram showing the relationship between battery temperature and SOC and charge/discharge allowable power. FIG. 3 is a diagram showing the relationship between the current and current phase angle of a motor generator and torque. Vehicle braking power balance when the necessary braking torque can be generated without using a mechanical brake by performing charge amount suppression control with both the first motor generator and the second motor generator in regenerative operation. FIG. FIG. 6 is a diagram showing the power balance of vehicle braking when charge amount suppression control is not performed while both the first motor generator and the second motor generator are in regenerative operation. Vehicle braking power balance when the necessary braking torque can be generated by performing charge amount suppression control with both the first motor generator and the second motor generator in regenerative operation and further using a mechanical brake. FIG. FIG. 6 is a diagram showing the power balance of vehicle braking when charge amount suppression control is performed with the first motor generator operating in power and the second motor generator operating in regeneration.

Hereinafter, a vehicle power control device 10 according to an embodiment of the present disclosure will be described with reference to the drawings. The vehicle 20 on which the power control device 10 of the present embodiment is mounted is an electric vehicle that includes a drive device 30 including a first motor generator MG1 and a second motor generator MG2 as driving power sources. FIG. 1 is a diagram showing the configuration of a drive device 30 of a vehicle 20 on which a power control device 10 is mounted. The first motor generator MG1 and the second motor generator MG2 can both consume electric power and generate power through power operation, and can generate power through regenerative operation.

The drive device 30 includes a transmission mechanism 2 that transmits the power of a first motor generator MG1 and a second motor generator MG2 to the wheels 1. The transmission mechanism 2 includes a first reduction gear 11, a second reduction gear 21, a final reduction gear 31 including a differential, and a planetary gear that combines the power of the first motor generator MG1 and the power of the second motor generator MG2. A mechanism 4 is provided. The output of the planetary gear mechanism 4 is transmitted to the left and right wheels 1 via the final reduction gear 31.

The planetary gear mechanism 4 includes a first sun gear 41 , a second sun gear 42 , a planetary carrier 43 , an inner planetary pinion 44 that is rotatably supported by the planetary carrier 43 and meshes with the first sun gear 41 , and a planetary carrier 43 that rotates. and an outer planetary pinion 45 that is movably supported and meshes with the second sun gear 42 and the inner planetary pinion 44 . The first sun gear 41, the second sun gear 42, and the planetary carrier 43 are rotatable around a common axis.

The planetary gear mechanism 4 includes a first planetary gear train 46 including a first sun gear 41, an inner planetary pinion 44, and an outer planetary pinion 45, and a second planetary gear train 47 including a second sun gear 42 and an outer planetary pinion 45. It is a complex planetary gear mechanism. The first planetary gear train 46 is a double pinion type planetary gear train, and the second planetary gear train 47 is a single pinion type planetary gear train.

The planetary gear mechanism 4 is a three-element, two-degree-of-freedom mechanism, and when the rotational speed of two of the three elements is determined, the rotational speed of the remaining one element is uniquely determined. For example, when the rotation speeds of the first sun gear 41 and the second sun gear 42 are determined, the rotation speed of the planetary carrier 43 is determined accordingly.

The rotating shaft 12 of the first motor generator MG1 is connected to the first input shaft 13 via the first reduction gear 11, and the first input shaft 13 is fixed to the first sun gear 41. The rotating shaft 22 of the second motor generator MG2 is connected to the second input shaft 23 via the second reduction gear 21, and the second input shaft 23 is fixed to the second sun gear 42. An output gear 32 is fixed to the planetary carrier 43, and the output gear 32 forms a final reduction gear pair 34 together with a driven gear 33 that rotates together with the differential gear.

The transmission system from the second motor generator MG2 to the second sun gear 42 is provided with a one-way clutch 35 that allows rotation of the second sun gear 42 in the rotation direction when the vehicle 20 moves forward and prevents rotation in the reverse direction. ing. Further, each wheel shaft 36 is provided with a mechanical brake 37. The mechanical brake 37 mechanically reduces the rotational force of the wheel 1 by pressing a brake pad against a brake disc or the like fixed to each wheel axle 36 when brake pressure is transmitted via a hydraulic circuit (not shown). can do.

The drive device 30 operates in a first driving mode in which the vehicle 20 is driven only by the output of the first motor generator MG1, and a second driving mode in which the vehicle 20 is driven by the outputs of both the first motor generator MG1 and the second motor generator MG2. It can be driven in two driving modes.

In the first running mode, the output of the first motor generator MG1 is transmitted to the first input shaft 13 and the first sun gear 41 via the first reduction gear 11, and operates the first planetary gear train 46. As the first planetary gear train 46 operates, torque is also transmitted to the second planetary gear train 47 to try to rotate the second sun gear 42, but when the vehicle is moving forward, the rotation of the second sun gear 42 is This is prevented by the one-way clutch 35. As a result, the rotation speeds of two of the three elements (first sun gear 41 and second sun gear 42) are determined, and the rotation speed of the remaining one element (planetary carrier 43) is determined.

In the second driving mode, the output of the first motor generator MG1 is transmitted to the first input shaft 13 and the first sun gear 41 via the first reducer 11, and the output of the second motor generator MG2 is transmitted to the second reducer 21. The signal is transmitted to the second input shaft 23 and the second sun gear 42 via the input shaft 23 and the second sun gear 42 . Then, since the rotation speeds of the two elements (first sun gear 41 and second sun gear 42) are determined, the rotation speed of the remaining one element (planetary carrier 43) is determined.

Furthermore, while the vehicle 20 is traveling at a certain speed in the second travel mode, the rotational speed of the planetary carrier 43 is determined according to the speed of the vehicle 20. In this case, the rotational speeds of the first motor generator MG1 and the second motor generator MG2 are mutually restricted but can be changed. Therefore, by operating the first motor generator MG1 and the second motor generator MG2 at efficient rotational speeds, the power consumption of the first motor generator MG1 and the second motor generator MG2 can be reduced.

As shown in FIG. 2, the vehicle 20 includes a battery 5 that can be charged and discharged by transferring power to and from a first motor generator MG1 and a second motor generator MG2, and a first inverter 6 that drives the first motor generator MG1. A second inverter 7 that drives a second motor generator MG2 is provided. The first motor generator MG1 is electrically connected to the battery 5 via the first inverter 6, and the second motor generator MG2 is electrically connected to the battery 5 via the second inverter 7.

The vehicle 20 also includes a vehicle speed sensor 51 that outputs a signal corresponding to the speed of the vehicle 20, an accelerator depression amount sensor 52 that outputs a signal that corresponds to the amount of depression of the accelerator pedal, and a signal that corresponds to the amount of depression of the brake pedal. A brake depression sensor 53 outputs a signal, an SOC sensor 54 outputs a signal corresponding to the charge amount of the battery 5, and a battery temperature sensor 55 outputs a signal corresponding to the temperature of the battery 5. As shown in FIG. 2, output signals from a vehicle speed sensor 51, an accelerator depression amount sensor 52, a brake depression amount sensor 53, an SOC sensor 54, a battery temperature sensor 55, etc. are input to the power control device 10.

The power control device 10 has a CPU, which is an arithmetic processing unit, and storage units such as RAM and ROM. Controls such as drive control of the first motor generator MG1 and second motor generator MG2 and operation control of the mechanical brake 37 are executed. The power control device 10 causes the vehicle 20 to run using the first running mode and the second running mode when driving, and runs the vehicle 20 only in the second running mode when braking. FIG. 3 is a flowchart showing a control routine executed by power control device 10 when braking vehicle 20. The control routine program shown in FIG. 3 is held in the ROM of the power control device 10, and is repeatedly executed in an extremely short cycle time of, for example, several milliseconds.

In this control routine, the power control device 10 first determines the braking torque Tbr of the vehicle 20 from the vehicle speed, the amount of accelerator depression, and the amount of brake depression in step S1. Next, in step S2, the power control device 10 converts the torque Tc of the output shaft of the planetary gear mechanism 4 from the braking torque Tbr determined in step S1 based on the reduction ratio of the final reduction gear 31.

Next, in step S3, power control device 10 determines torque T1 of first motor generator MG1 and torque T2 of second motor generator MG2. When braking, the vehicle 20 always runs in the second travel mode, so if the reduction ratio of the first reduction gear 11 is G1, the reduction ratio of the second reduction gear 21 is G2, and the reduction ratio of the planetary gear mechanism 4 is ρ, then The following relational expressions (Formula 1) and (Formula 2) hold true.

The torque T1 of the first motor generator MG1 is uniquely determined from the above (Formula 1), and the torque T2 of the second motor generator MG2 is uniquely determined from the above (Formula 2).

Next, in step S4, the power control device 10 determines the rotational speed of the first motor generator MG1 to be N1 and the rotational speed N2 of the second motor generator MG2 so that the mechanical loss of the transmission mechanism 2 is minimized. do. When the rotational speed of the output shaft of the planetary gear mechanism 4 is Nc, the following relational expression (Equation 3) holds true between the rotational speed Nc, the rotational speed N1, and the rotational speed N2.

The rotational speed N1 and the rotational speed N2 are determined using the rotational speed Nc uniquely determined from the vehicle speed so as to satisfy the above (Formula 3). FIG. 4 is a diagram showing the relationship between the rotational speed N1, the rotational speed N2, and the magnitude of mechanical loss of the transmission mechanism 2 at the rotational speed N1 and the rotational speed N2 where the relationship of (Equation 3) above holds. be. The data shown in FIG. 4 is stored in advance in the ROM of the power control device 10. As shown in FIG. 4, the mechanical loss of the transmission mechanism 2 includes a mechanical loss of the planetary gear mechanism 4, a mechanical loss of the first reducer 11, and a mechanical loss of the second reducer 21. and the total mechanical loss of the final reduction gear 31. In FIG. 4, the rotational speeds of the first motor generator MG1 and the second motor generator MG2 are expressed with the regeneration direction being positive. The rotational speed N2 increases as it goes to the right from the left end of the graph in FIG. 4 as the origin, and the second motor generator MG2 always performs a regenerative operation. Conversely, the rotational speed N1 increases toward the left in the graph of FIG. 4, and the first motor generator MG1 performs a regenerative operation on the left side of the origin, and the first motor generator MG1 performs a power operation on the right side of the origin.

When the rotational speed N1, the rotational speed N2, and the mechanical loss of the transmission mechanism 2 have the relationship shown in FIG. 4, the mechanical loss of the transmission mechanism 2 is minimized at the position indicated by the arrow A1 in FIG. Therefore, in step S4, the power control device 10 determines the rotational speed N1 and the rotational speed N2 at the position indicated by the arrow A1.

Next, in step S5, the power control device 10 drives the first motor generator MG1 using MTPA (Maximum Torque Per Ampere) control at the rotational speed N1 determined in step S4, and drives the first motor generator MG1 at the rotational speed N2 determined in step S4. Electric power Pb charged to battery 5 when motor generator MG2 is driven under MTPA control is calculated. The electric power Pb charged in the battery 5 is calculated from the torque T1 and torque T2 determined in step S3 and the rotational speed N1 and rotational speed N2 determined in step S4, as described below.

The output of the first motor generator MG1 is the product of the torque T1 and the rotational speed N1, and the output of the second motor generator MG2 is the product of the torque T2 and the rotational speed N2. Therefore, the electric power Pb charged in the battery 5 is: It is expressed by the following (Formula 4). However, L1 in (Equation 4) is the sum of the loss of the first motor generator MG1 and the loss of the first inverter 6 when the first motor generator MG1 is driven by MTPA control at the rotational speed N1 determined in step S4. be. L2 in (Equation 4) is the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 when the second motor generator MG2 is driven by MTPA control at the rotational speed N2 determined in step S4. be. Since L1 in (Equation 4) varies depending on the torque T1 and the rotational speed N1, the value of L1 under each drive condition is stored in advance in the ROM of the power control device 10. Since L2 in (Formula 4) also varies depending on the torque T2 and the rotational speed N2, the value of L2 under each drive condition is also stored in advance in the ROM of the power control device 10.

Pb=(T2N2-L2)+(T1N1-L1)...(Formula 4)

Next, in step S6, the power control device 10 calculates the allowable charging power Win based on the temperature and SOC of the battery 5. As disclosed in Patent Document 3, the allowable charge power Win is calculated using the map of FIG. 5 showing the relationship between the temperature Tb and SOC of the battery 5 and the allowable charge power Win. The data shown in FIG. 5 is stored in the ROM of the power control device 10 in advance. As shown in FIG. 5, when the temperature Tb of the battery 5 is below Tb0 on the low temperature side or above Tb2 on the high temperature side, charging and discharging is not possible. Charge allowable power Win and discharge allowable power Wout change depending on temperature Tb and SOC. For example, if we pay attention to the IVp section indicating the charging side (power negative side) where the temperature Tb of the battery 5 is around 0°C, as the SOC decreases from 60% to 50% to 40%, the charging tolerance, which is the absolute value of the power, increases. Power Win increases. Since the power control device 10 can accurately calculate the allowable charging power Win using the map in FIG. 5 in step S6, it is possible to avoid overcharging the battery 5 in steps S8 and S9, which will be described later. , the life of the battery 5 can be extended.

Next, in step S7, it is determined whether the electric power Pb charged to the battery 5 is equal to or less than the charging allowable electric power Win, based on the calculation results of steps S5 and S6. If the power Pb charged to the battery 5 is less than or equal to the allowable charging power Win, the process advances to step S8, and if the power Pb charged to the battery 5 is greater than the allowable charging power Win, the process advances to step S9.

When the process advances from step S7 to step S8, the power control device 10 performs normal control in step S8. If the process proceeds from step S7 to step S9, the power control device 10 performs charge amount suppression control in step S9. In both the normal control in step S8 and the charge amount suppression control in step S9, the first motor generator MG1 is operated to generate the torque T1 determined in step S3, and the first motor generator MG1 is operated to generate the torque T2 determined in step S3. It is common that the two motor generators MG2 are operated.

However, in the normal control in step S8, the power control device 10 drives the first motor generator MG1 by MTPA control at the rotation speed N1 determined in step S4, and drives the second motor generator MG2 at the rotation speed N2 determined in step S4. is driven by MTPA control. By driving the first motor generator MG1 and the second motor generator MG2 in this manner, the regenerative power of the first motor generator MG1 and the second motor generator MG2 is transferred to the battery 5 while ensuring the braking torque Tbr determined in step S1. can be charged to.

On the other hand, in the charge amount suppression control in step S9, the power control device 10 sets the rotation speed at which the mechanical loss of the transmission mechanism 2 is increased more than the rotation speed at which the mechanical loss of the transmission mechanism 2 is minimized. Then, it is driven by the first motor generator MG1 and the second motor generator MG2. Then, the power control device 10 calculates the sum of the loss of the motor generator in the regenerative operation among the first motor generator MG1 and the second motor generator MG2 and the loss of the inverter that drives the motor generator in the regenerative operation, using the MTPA control. The motor generator in regenerative operation is driven under the increased drive condition. The power control device 10 thus increases the mechanical loss of the transmission mechanism 2 and increases the total of the loss of the motor generator and the loss of the inverter during regenerative operation, but the battery 5 cannot be charged. If the electric power Pb cannot be lower than the allowable charge power Win, the mechanical brake 37 is further used to control the electric power Pb charged to the battery 5 to be equal to or lower than the allowable charge power Win. The charge amount suppression control in step S9 will be described below using a specific example.

In the charge amount suppression control in step S9, for example, the rotational speed N1 and the rotational speed N2 at the position indicated by the arrow A2 in FIG. 4 where the mechanical loss of the transmission mechanism 2 is larger than the position indicated by the arrow A1 in FIG. Assume that the first motor generator MG1 and the second motor generator MG2 are respectively driven. In this case, since both the first motor generator MG1 and the second motor generator MG2 perform regenerative operation, the drive condition is such that the sum of the loss of the first motor generator MG1 and the loss of the first inverter 6 is increased more than the MTPA control. The first motor generator MG1 is driven, and the second motor generator MG2 is driven under a driving condition that increases the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 compared to the MTPA control.

The relationship between the current and current phase angle of the first motor generator MG1 and the torque is as shown in FIG. 6, as disclosed in Non-Patent Document 1. It is assumed that the torque T1 calculated in step S3 is at the height indicated by the dotted line in FIG. When performing MTPA control, the first motor generator MG1 is driven at the current phase angle of the part surrounded by circle A in FIG. 6, where the torque is maximum at the current value _I2 , but the charge amount suppression in step S9 In the control, for example, the first motor generator MG1 is driven at a current value _I3 at a current phase angle of a portion surrounded by a circle B in FIG. In this way, by driving the first motor generator MG1 with the current value _I3 and the current phase angle of the part surrounded by the circle B in FIG. The first motor generator MG1 can be driven under driving conditions that increase the sum of the loss of the first inverter 6 and the loss of the first inverter 6 compared to the MTPA control. Similarly, the power control device 10 controls the second motor generator MG2 under driving conditions that increase the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 compared to the MTPA control. drive.

FIG. 7 shows vehicle braking when the first motor generator MG1 and the second motor generator MG2 are operated regeneratively at the rotational speed N1 and the rotational speed N2 at the positions indicated by the arrow A2 in FIG. 4 in the charge amount suppression control in step S9. FIG. The magnitude of the deceleration power of the vehicle 20 shown in FIG. 7 is determined by the braking torque Tbr calculated in step S1 and the vehicle speed. This deceleration power is equal to the sum of the output of the first motor generator MG1, the output of the second motor generator MG2, the mechanical loss of the transmission mechanism 2, and the output of the mechanical brake 37. However, since FIG. 7 describes an example in which the braking torque Tbr calculated in step S1 can be generated without using the mechanical brake 37 by performing charge amount suppression control, FIG. , the output of the mechanical brake 37 is zero.

Further, as shown in FIG. 7, the output of the second motor generator MG2 is A, the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 is B, the output of the first motor generator MG1 is C, and the output of the first motor generator MG1 is C. When the sum of the loss of the first motor generator MG1 and the loss of the first inverter 6 is D, the electric power Pb charged in the battery 5 is expressed by the following (Formula 5).

Pb=(AB)+(CD)...(Formula 5)

Therefore, when the charge amount suppression control is performed, the mechanical loss of the transmission mechanism 2 is increased, the total loss of the first motor generator MG1 and the first inverter 6 is increased, and the loss of the second motor generator MG1 is increased. By increasing the sum of the loss of MG2 and the loss of second inverter 7, it is possible to reduce the electric power Pb charged to battery 5 without reducing the braking forces of first motor generator MG1 and second motor generator MG2. can.

For reference, under the same conditions of the deceleration power of the vehicle 20 as in FIG. 7, the first motor generator MG1 and the second motor generator MG1 and the second FIG. 8 shows the power balance of vehicle braking when motor generator MG2 is driven by MTPA control. In this case, if the deceleration power of the vehicle 20 is made the same as in FIG. 7, and the electric power Pb charged in the battery 5 is also made to be the same as in FIG. 7, it is necessary to also use the braking force of the mechanical brake 37 as shown in FIG. be. That is, by performing the charge amount suppression control in step S9, it is possible to reduce the frequency of use of the mechanical brake 37 and extend the life of the mechanical brake 37.

Further, under conditions where the value of the braking torque Tbr calculated in step S1 is different, even if the charge amount suppression control is performed in step S9, as shown in the power balance of vehicle braking shown in FIG. 9, the mechanical brake 37 must be further used. , it may be impossible to generate the braking torque Tbr calculated in step S1. Even in such a case, as shown in FIG. 8, the first motor generator MG1 and the second motor generator MG2 are operated at the rotational speed at the position indicated by the arrow A1 in FIG. 4, where the mechanical loss of the transmission mechanism 2 is minimized. By performing the charge amount suppression control in step S9, the output of the mechanical brake 37 can be reduced compared to the case where the mechanical brake 37 is driven by MTPA control. The durability of the product can be extended.

Next, in the charge amount suppression control in step S9, the power control device 10 drives the first motor generator MG1 and the second motor generator MG2 at the rotational speed N1 and the rotational speed N2 at the positions indicated by arrow A3 in FIG. 4, respectively. Let's explain the case. In this case, the first motor generator MG1 performs the power operation, and only the second motor generator MG2 performs the regeneration operation. Therefore, the first motor generator MG1 is driven by MTPA control, and the second motor generator MG2 is driven under a driving condition that increases the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 compared to the MTPA control.

FIG. 10 shows vehicle braking when the first motor generator MG1 and the second motor generator MG2 are respectively driven at the rotational speed N1 and the rotational speed N2 at the positions indicated by the arrow A3 in FIG. 4 in the charge amount suppression control in step S9. FIG. The magnitude of the deceleration power of the vehicle 20 shown in FIG. 10 is determined by the braking torque Tbr calculated in step S1 and the vehicle speed. Assuming that the output of the second motor generator MG2 that performs regenerative operation is a positive output and the output of the first motor generator MG1 that performs power operation is a negative output, the magnitude of this deceleration power is as shown in FIG. It is the same as the sum of the output of the first motor generator MG1, the output of the second motor generator MG2, the mechanical loss of the transmission mechanism 2, and the output of the mechanical brake 37.

Further, as shown in FIG. 10, the output of the second motor generator MG2 is A, the sum of the loss of the second motor generator MG2 and the loss of the second inverter 7 is B, the output of the first motor generator MG1 is C, and the output of the first motor generator MG1 is C. When the sum of the loss of the first motor generator MG1 and the loss of the first inverter 6 is D, the electric power Pb charged in the battery 5 is expressed by the following (Formula 6).

Pb=(AB)-(CD)...(Formula 6)

Therefore, even if charge amount suppression control is performed with the first motor generator MG1 in power operation and the second motor generator MG2 in regenerative operation, the mechanical loss of the transmission mechanism 2 will increase, and the second motor generator MG2 will increase the mechanical loss. By increasing the sum of the loss of motor generator MG2 and the loss of second inverter 7, electric power Pb charged to battery 5 can be reduced without reducing the braking force of second motor generator MG2. Moreover, as a result, the frequency of use of the mechanical brake 37 can be reduced, and the life of the mechanical brake 37 can be extended.

As described above, when the power control device 10 drives the first motor generator MG1 and the second motor generator MG2 under MTPA control at a rotation speed that minimizes the mechanical loss of the transmission mechanism 2 when braking the vehicle 20, the battery If the electric power Pb charged in the motor generator 5 becomes larger than the allowable charging electric power Win, the process advances to step S9, where charging amount suppression control is performed without reducing the braking forces of the first motor generator MG1 and the second motor generator MG2. The electric power Pb charged to the battery 5 can be reduced. Furthermore, as a result, the frequency of use of the mechanical brake 37 can be reduced and the life of the mechanical brake 37 can be extended without adding an auxiliary brake such as a retarder to the vehicle 20.

<Supplementary information on the embodiment>
The power control device for a vehicle according to the present disclosure is not limited to the above-mentioned form, but can be implemented in various forms within the scope of the gist of the present disclosure. For example, the vehicle 20 equipped with the power control device 10 is not limited to an electric vehicle equipped with two motor generators as driving power sources, but may also be a series-type hybrid vehicle equipped with an internal combustion engine. Further, the vehicle 20 on which the power control device 10 is mounted may be a vehicle in which the drive device 30 is not equipped with the first reduction gear 11 and the second reduction gear 21.

Further, in the above-described embodiment, in the charge amount suppression control in step 9, the first motor generator MG1 and the second motor generator MG2 are driven at a rotation speed that increases the mechanical loss of the transmission mechanism 2, and furthermore, during the regenerative operation. The motor generator and inverter are driven under conditions that increase their losses more than in MTPA control. However, even when driven under MTPA control, by driving the first motor generator MG1 and the second motor generator MG2 at a rotation speed that increases the mechanical loss of the transmission mechanism 2, the first motor generator MG1 and the second motor generator MG2 The effect of reducing electric power Pb charged into battery 5 can be produced without reducing the braking force of motor generator MG2. Therefore, the charge amount suppression control in step 9 is performed to control the first motor generator MG1 and the second motor generator MG1 at a rotation speed that increases the mechanical loss of the transmission mechanism 2 rather than the rotation speed at which the mechanical loss of the transmission mechanism 2 is minimized. Control may be such that motor generator MG2 is driven by MTPA control.

1 Wheel, 2 Transmission mechanism, 4 Planetary gear mechanism, 5 Battery, 6 First inverter, 7 Second inverter, 10 Power control device, 11 First reduction gear, 12 Rotating shaft, 13 First input shaft, 20 Vehicle, 21 2nd reduction gear, 22 rotating shaft, 23 second input shaft, 30 drive device, 31 final reduction gear, 32 output gear, 33 driven gear, 34 final reduction gear pair, 35 one-way clutch, 36 wheel shaft, 37 mechanical brake , 41 first sun gear, 42 second sun gear, 43 planetary carrier, 44 inner planetary pinion, 45 outer planetary pinion, 46 first planetary gear train, 47 second planetary gear train, 51 vehicle speed sensor, 52 accelerator depression amount sensor, 53 Brake depression amount sensor, 54 SOC sensor, 55 battery temperature sensor, MG1 first motor generator, MG2 second motor generator.

Claims (3)

two motor generators that can generate power by consuming electric power through power operation and can generate power through regenerative operation;
a battery that can be charged and discharged by transferring power to and from the two motor generators;
a transmission mechanism that includes a planetary gear mechanism that combines the power of the two motor generators and transmits the output of the planetary gear mechanism to the wheels;
A power control device for a vehicle comprising:
When the two motor generators are driven under MTPA (Maximum Torque Per Ampere) control at a rotational speed that minimizes mechanical loss of the transmission mechanism when the vehicle is braked, the electric power charged to the battery is If the charging power exceeds the allowable charging power of the battery,
A power control device for a vehicle, characterized in that the two motor generators are driven at a rotation speed that increases mechanical loss of the transmission mechanism rather than a rotation speed at which mechanical loss of the transmission mechanism is minimized. The vehicle power control device according to claim 1,
When the two motor generators are driven by MTPA control at a rotational speed that minimizes mechanical loss of the transmission mechanism when the vehicle is braked, the electric power charged to the battery is lower than the allowable charging electric power of the battery. If it gets bigger,
The motor during regenerative operation under driving conditions that increases the sum of the loss of the motor generator of the two motor generators during regenerative operation and the loss of the inverter that drives the motor generator that drives the motor generator during regenerative operation than the MTPA control. A vehicle power control device characterized by driving a generator. The vehicle power control device according to claim 1 or 2,
A power control device for a vehicle, wherein the allowable power for charging the battery is calculated based on the temperature and SOC (State of Charge) of the battery.

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