JP4840374B2 - Electric vehicle, method for controlling electric vehicle, and computer-readable recording medium recording program for causing computer to execute the control method - Google Patents

Description

  The present invention relates to electric power control of an electric vehicle including a power supply unit including a plurality of power storage devices.

  Recently, attention has been focused on electric vehicles equipped with an electric motor as a power source such as a hybrid vehicle and an electric vehicle. In these electric vehicles, in order to improve the running performance such as the acceleration performance and the running distance, the development of an increase in capacity of the power source is being promoted. As a means for increasing the capacity of the power supply unit, a configuration having a plurality of power storage devices and a plurality of converters has been proposed.

For example, Di Napoli et al.'S "Multi-input DC-DC power converter for power flow management in a hybrid vehicle" includes a capacitor and a battery as a plurality of power storage devices, and the DC-DC corresponding to each of the capacitor and the battery. A configuration of a power supply device including a converter is disclosed. And Di Napoli et al. Disclose that the converter corresponding to the capacitor is current-controlled (power control) and the converter corresponding to the battery is voltage-controlled (see Non-Patent Document 1).
JP 2005-51850 A Di Napoli, A and 4 others, “Multi-Input DC-DC Power Converter for Power-Flow Management in Hybrid Vehicles”, (USA), 2002 Industrial Application Conference, 37th IAS Annual Meeting, 2002, 37th IAS Annual Meeting. Conference Record of the 2002 IEEE, 2002, vol. . 3, p. 1578-1585

  In an electric vehicle, when the drive wheel slips on an icy road, or when the drive wheel idles when the drive wheel jumps up on a wavy road, the rotational speed of the drive wheel suddenly increases and the output of the motor increases temporarily. To do. For this reason, high power is temporarily supplied from the power supply unit to the electric motor.

  On the other hand, in an electric vehicle equipped with a plurality of power storage devices, power distribution is generally performed so that the charge / discharge power of the plurality of power storage devices is equalized so that the load is not concentrated on a specific power storage device. .

  Here, when the voltage control is performed on one of the plurality of converters connected in parallel to the DC link and the current control (power control) is performed on the other, as in the power supply device disclosed in the above-mentioned Di Napoli et al. The output power of the power storage device corresponding to the converter on the voltage control side (battery in Di Napoli et al.) Can exceed the upper limit when slipping occurs or when the driving wheel idles on a wavy road.

  That is, even if the output of the motor suddenly increases at the time of slip occurrence, a delay in recognizing output fluctuation occurs due to filter processing and signal transmission delay at the time of taking in the rotation speed, and as a result, the output of the motor is actually However, there is a situation in which there is a delay in changing the power distribution among the plurality of power storage devices despite the rapid increase. At this time, since the converter on the current control (power control) side performs current control (power control) based on the state before the output sudden increase due to slip or the like, only the power storage device corresponding to the converter on the voltage control side can increase the output. The output power of the power storage device may exceed the upper limit.

  On the other hand, when the slip state or idling state changes to the grip state, the rotational speed of the drive wheel decreases rapidly, and the output of the electric motor decreases temporarily. Then, when power generation is performed by a power generation device using an engine or the like, the input power (charging power) of the power storage device may now exceed the upper limit due to a delay in recognition of output fluctuations similar to when slipping or idling occurs.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide an electric vehicle capable of controlling the input / output power of the power storage device within a limit value even if the rotation speed of the electric motor changes suddenly. It is to be.

  Another object of the present invention is to provide a method for controlling an electric vehicle capable of controlling the input / output power of the power storage device within a limit value even when the rotational speed of the motor suddenly changes, and a program for causing a computer to execute the control method Is a computer-readable recording medium on which is recorded.

  According to the present invention, the electric vehicle includes the driving force generation unit, the power supply unit, and the control unit. The driving force generator is configured to be able to generate a driving force of the vehicle by an electric motor. The power supply unit can exchange power via the driving force generation unit and the power line. The control unit controls the driving force generation unit and the power supply unit. The power supply unit includes chargeable / dischargeable first and second power storage devices and first and second converters. The first converter is provided between the first power storage device and the power line. The second converter is provided between the second power storage device and the power line. The control unit includes a power calculation unit, a voltage control unit, a power control unit, and a power limit control unit. The power calculation unit calculates a required power for the driving force generation unit. The voltage control unit controls the first converter so that the voltage of the power line becomes a predetermined target voltage. The power control unit controls the second converter so that the charge / discharge power of the second power storage device becomes a predetermined target power. The power limit control unit limits the required power for the driving force generation unit to a value obtained by adding the charge / discharge power of the second power storage device to the power limit value for the first power storage device.

  Preferably, the control unit further includes a determination unit that determines whether or not the output rotational speed of the driving force generation unit has suddenly changed. The power control unit controls the second converter so that the charge / discharge power of the second power storage device becomes substantially zero when the determination unit determines that the output rotation speed has suddenly changed.

  Preferably, the power control unit controls the current of the second converter so that the charge / discharge power of the second power storage device becomes the target power.

  According to the present invention, the control method is a control method for an electric vehicle. The electric vehicle includes a driving force generation unit and a power supply unit. The driving force generator is configured to be able to generate a driving force of the vehicle by an electric motor. The power supply unit can exchange power via the driving force generation unit and the power line. The power supply unit includes chargeable / dischargeable first and second power storage devices and first and second converters. The first converter is provided between the first power storage device and the power line. The second converter is provided between the second power storage device and the power line. The control method includes a step of calculating a required power for the driving force generator, a step of controlling the first converter so that the voltage of the power line becomes a predetermined target voltage, and the charge / discharge power of the second power storage device is predetermined. The power required for the driving force generator is added to the value obtained by adding the charge / discharge power of the second power storage device to the power limit value for the first power storage device Limiting.

  Preferably, the control method further includes a step of determining whether or not the output rotational speed of the driving force generator has changed suddenly. Then, when it is determined that the output rotation speed has suddenly changed, in the step of controlling the second converter, the second converter is controlled such that the charge / discharge power of the second power storage device becomes substantially zero.

  Preferably, in the step of controlling the second converter, the current of the second converter is controlled such that the charge / discharge power of the second power storage device becomes the target power.

  According to the invention, the recording medium is a computer-readable recording medium, and records a program for causing the computer to execute any one of the above-described methods for controlling an electric vehicle.

  In the present invention, the first and second converters are connected to the power line in parallel with each other. The first converter is voltage-controlled so that the voltage of the power line becomes a predetermined target voltage. The second converter is subjected to power control (current control) so that the charge / discharge power of the second power storage device becomes a predetermined target power. Since the power limit control unit limits the required power for the driving force generation unit to a value obtained by adding the charge / discharge power of the second power storage device to the power limit value for the first power storage device, the first power storage device The charging / discharging electric power does not exceed the electric power limit value for the first power storage device.

  Therefore, according to the present invention, the input / output power of the power storage device can be controlled within the limit value even if the rotational speed of the electric motor changes suddenly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is an overall block diagram of an electric vehicle according to Embodiment 1 of the present invention. Referring to FIG. 1, electric vehicle 100 includes a power supply unit 1, a driving force generation unit 2, an HV-ECU (Electronic Control Unit) 3, a main positive bus MPL, a main negative bus MNL, and a capacitor C. The voltage sensor 18 is provided.

  The power supply unit 1 includes power storage devices 6-1 and 6-2, converters 8-1 and 8-2, a battery ECU 4, current sensors 10-1 and 10-2, and voltage sensors 12-1 and 12-2. Including.

  The power storage devices 6-1 and 6-2 are DC power sources that can be charged and discharged, and include, for example, secondary batteries such as lithium ion batteries and nickel metal hydride batteries. Power storage device 6-1 is connected to converter 8-1 through positive electrode line PL1 and negative electrode line NL1. Power storage device 6-2 is connected to converter 8-2 via positive electrode line PL2 and negative electrode line NL2. Note that at least one of the power storage devices 6-1 and 6-2 may be formed of an electric double layer capacitor.

  Converter 8-1 is provided between power storage device 6-1 and main positive bus MPL and main negative bus MNL, and based on drive signal PWC1 from HV-ECU 3, power storage device 6-1 and main positive bus MPL. Voltage conversion is performed with the main negative bus MNL. Converter 8-2 is provided between power storage device 6-2 and main positive bus MPL and main negative bus MNL, and based on drive signal PWC2 from HV-ECU 3, power storage device 6-2 and main positive bus MPL. Voltage conversion is performed with the main negative bus MNL. In other words, converters 8-1 and 8-2 are connected in parallel to main positive bus MPL and main negative bus MNL.

  Current sensor 10-1 detects current Ib1 input / output to / from power storage device 6-1, and outputs the detected value to battery ECU 4 and HV-ECU 3. Current sensor 10-2 detects current Ib2 input / output to / from power storage device 6-2, and outputs the detected value to battery ECU 4 and HV-ECU 3. Current sensors 10-1 and 10-2 detect a current (discharge current) output from the corresponding power storage device as a positive value, and a current (charge current) input to the corresponding power storage device as a negative value. To detect. FIG. 1 shows the case where the current sensors 10-1 and 10-2 detect the currents of the positive lines PL1 and PL2, respectively. However, the current sensors 10-1 and 10-2 are respectively connected to the negative line NL1. , NL2 current may be detected.

  Voltage sensor 12-1 detects a voltage between positive electrode line PL1 and negative electrode line NL1, that is, voltage Vb1 of power storage device 6-1, and outputs the detected value to battery ECU 4 and HV-ECU 3. Voltage sensor 12-2 detects a voltage between positive electrode line PL2 and negative electrode line NL2, that is, voltage Vb2 of power storage device 6-2, and outputs the detected value to battery ECU 4 and HV-ECU 3.

  Battery ECU 4 determines the state of charge of power storage device 6-1 (hereinafter referred to as “SOC (State of Charge)”) based on the detected value of current Ib1 from current sensor 10-1 and the detected value of voltage Vb1 from voltage sensor 12-1. The state quantity SOC1 is also calculated. Battery ECU 4 calculates state quantity SOC2 indicating the SOC of power storage device 6-2 based on the detected value of current Ib2 from current sensor 10-2 and the detected value of voltage Vb2 from voltage sensor 12-2. .

  Then, battery ECU 4 outputs the calculated state quantities SOC1 and SOC2 to HV-ECU3. Battery ECU 4 also includes discharge power upper limit values Wout1, Wout2 indicating the upper limit of the discharge power of power storage devices 6-1 and 6-2, and charge power upper limit value indicating the upper limit of the charge power of power storage devices 6-1 and 6-2. Win1 and Win2 are output to the HV-ECU 3.

  The driving force generator 2 includes inverters 20-1 and 20-2, motor generators MG 1 and MG 2, a power transmission mechanism 22, and a drive shaft 24.

  Inverters 20-1 and 20-2 are connected in parallel to main positive bus MPL and main negative bus MNL. Inverters 20-1 and 20-2 convert drive power (DC power) supplied from main positive bus MPL and main negative bus MNL into AC power and output the AC power to motor generators MG1 and MG2, respectively. Inverters 20-1 and 20-2 convert AC power generated by motor generators MG1 and MG2 into DC power, respectively, and output the power as regenerative power to main positive bus MPL and main negative bus MNL.

  Motor generators MG1 and MG2 receive AC power supplied from inverters 20-1 and 20-2, respectively, and generate rotational driving force. In addition, motor generators MG1 and MG2 receive rotational force from the outside and generate AC power. Motor generators MG1 and MG2 are made of, for example, a three-phase AC rotating electric machine including a rotor having a permanent magnet embedded therein and a stator having a Y-connected three-phase coil. Motor generators MG 1, MG 2 are connected to power transmission mechanism 22, and a rotational driving force is transmitted to wheels (not shown) via drive shaft 24 further connected to power transmission mechanism 22.

  When electric powered vehicle 100 is a hybrid vehicle, motor generators MG1 and MG2 are also coupled to an engine (not shown) via power transmission mechanism 22 or drive shaft 24. Then, control is executed by HV-ECU 3 such that the driving force generated by the engine and the driving force generated by motor generators MG1, MG2 have an optimal ratio. One of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator.

  Capacitor C is connected between main positive bus MPL and main negative bus MNL, and reduces a power fluctuation component included in main positive bus MPL and main negative bus MNL. Voltage sensor 18 detects a voltage Vh between main positive bus MPL and main negative bus MNL, and outputs the detected value to HV-ECU 3.

  The HV-ECU 3 calculates the required power for the driving force generation unit 2 based on the traveling state of the vehicle, the accelerator opening, the SOC of the power storage devices 6-1 and 6-2, and the like. Then, HV-ECU 3 generates drive signals PWI1 and PWI2 for driving motor generators MG1 and MG2 based on the calculated required power, and inverters 20 generate generated drive signals PWI1 and PWI2, respectively. Output to -1,20-2.

  Further, HV-ECU 3 generates drive signals PWC1 and PWC2 for driving converters 8-1, 8-2, respectively, based on the required power, and converts the generated drive signals PWC1, PWC2 into converters, respectively. Output to 8-1 and 8-2.

  Here, HV-ECU 3 executes power distribution control of power storage devices 6-1 and 6-2 based on the required power. For example, HV-ECU 3 determines the power distribution of power storage devices 6-1 and 6-2 so that the required power is equally shared by power storage devices 6-1 and 6-2.

  For HV-ECU 3, converter 8-2 drives converter 8-2 so that the charge / discharge power of power storage device 6-2 becomes the power (target power) determined by the power distribution described above. Drive signal PWC2 is generated. For converter 8-1, HV-ECU 3 drives drive signal for driving converter 8-1 so that voltage Vh between main positive bus MPL and main negative bus MNL becomes a predetermined target voltage. PWC1 is generated.

  Further, even if the rotational speed of the drive wheel suddenly changes when the drive wheel slips or grips from the slip state, the HV-ECU 3 does not exceed the upper and lower limit values of the charge / discharge power of the power storage device 6-1. And power limitation control is performed by the method mentioned later so that the charging / discharging electric power of the electrical storage apparatus 6-2 may not exceed an upper / lower limit value.

  FIG. 2 is a diagram for explaining the concept of power limit control by the HV-ECU 3 shown in FIG. Referring to FIG. 2, Po represents the power generated by driving force generation unit 2, and Pb1 and Pb2 represent charge / discharge power of power storage devices 6-1 and 6-2, respectively. In the following, the power Po when the driving force generator 2 receives the supply of electric power from the power source 1 to generate the driving force of the vehicle is positive, and the driving force generator is used by using the kinetic energy of the vehicle and the engine output. The power Po when 2 generates regenerative power is negative. Further, charging / discharging power Pb1, Pb2 at the time of discharging power storage devices 6-1 and 6-2 is positive, and charging / discharging power Pb1, Pb2 at charging is negative.

  In FIG. 2, the concept of power limit control in the case where the rotational speed of the driving wheel suddenly increases due to the occurrence of slippage of the driving wheel will be described, but the rotational speed of the driving wheel suddenly decreases by gripping from the slip state. The concept of the power limit control can be similarly considered.

  In FIG. 2, the upper part shows power Po before the occurrence of slip and the charge / discharge powers Pb1 and Pb2 of power storage devices 6-1 and 6-2, and the lower part shows power Po and power storage devices 6-1 and 6-6 immediately after the slip. 2 shows charge / discharge power Pb1 and Pb2. For comparison, the power Po immediately after the slip and the charge / discharge powers Pb1 and Pb2 of the power storage devices 6-1 and 6-2 in the case where the power restriction control in the first embodiment is not performed (conventional equivalent) are shown in FIG. Shown in the middle row. In the following description, discharge power upper limit values Wout1 and Wout2 are the same value, but discharge power upper limit values Wout1 and Wout2 may be different values.

  Prior to the occurrence of slip, the power is distributed between the power storage devices 6-1 and 6-2 so that the power Po of the driving force generator 2 is evenly shared by the power storage devices 6-1 and 6-2. Pb2 is below the discharge power upper limit values Wout1 and Wout2, respectively.

  Here, when the drive wheel slips, the power Po rapidly increases as the rotational speed of the drive wheel rapidly increases. Conventionally, the upper limit value of the power Po is set to the sum of the discharge power upper limit values Wout1 and Wout2, and the output of the driving force generator 2 is limited so that the power Po does not exceed the sum of the discharge power upper limit values Wout1 and Wout2. (Middle of FIG. 2).

  By the way, the actual power Po increases due to the slip of the drive wheel, but a delay in recognizing the output fluctuation occurs in the HV-ECU 3 due to filter processing and signal transmission delay at the time of taking in the motor rotation speed. . This delay causes a delay in the power distribution control between the power storage devices 6-1 and 6-2, and the power Po is reflected in the power command of the power storage device 6-2 to be controlled even though the power Po is increasing. The situation that is not done temporarily occurs. During this time, the increase in power Po is borne by power storage device 6-1 corresponding to voltage-controlled converter 8-1, and conventionally, discharge power Pb1 of power storage device 6-1 has been There has been a problem that the discharge power upper limit Wout1 is exceeded (middle of FIG. 2).

  Therefore, in the first embodiment, the upper limit value of the power Po of the driving force generator 2 is not the sum of the discharge power upper limit values Wout1 and Wout2 of the power storage devices 6-1 and 6-2, but the power storage device 6 The discharge power upper limit value Wout1 of −1 is added to the current discharge power of the power storage device 6-2 (which may be a control target value or an actual value). . As a result, even if a situation that is not reflected in the power distribution control between the power storage devices 6-1 and 6-2 even though the power Po of the driving force generation unit 2 increases immediately after the slip, the power control is performed. Discharge power Pb1 of power storage device 6-1 that is not performed can also be suppressed within discharge power upper limit Wout1 (lower stage in FIG. 2).

  3 and 4 are diagrams showing temporal transitions of charge / discharge power Pb1 and Pb2 of power storage devices 6-1 and 6-2 at the time of occurrence of slip. For comparison, FIG. 3 shows a transition when the above-described power limit control in the first embodiment is not applied (conventional equivalent), and FIG. 4 shows a transition when the first embodiment is applied.

  Referring to FIG. 3, it is assumed that slip of the drive wheel has occurred at time t1. As the slip occurs, the output rotational speed of the driving force generator 2 increases. Here, as described above, there is a delay in the power distribution control between the power storage devices 6-1 and 6-2 due to the filter processing of the detected rotation speed, the signal transmission delay, etc., and the time t 1 is delayed. At time t2, the sudden increase in output due to the slip is reflected in the power distribution control, whereby the discharge power Pb2 of the power storage device 6-2 starts to increase.

  Here, since power upper limit value LMT of driving force generation unit 2 is defined by the sum of discharge power upper limit values Wout1 and Wout2 of power storage devices 6-1 and 6-2, direct power is supplied by corresponding converter 8-1. The upper limit of the discharge power of the uncontrolled power storage device 6-1 is substantially a value (Wout1 + Wout2-Pb2) indicated by a chain line, and exceeds the discharge power upper limit Wout1. Then, due to the delay of the power distribution control as described above, a situation has occurred in which the discharge power Pb1 of the power storage device 6-1 exceeds the discharge power upper limit value Wout1.

  On the other hand, referring to FIG. 4, in the first embodiment, power upper limit value LMT of driving force generation unit 2 is equal to discharge power upper limit value Wout1 of power storage device 6-1 and charging / discharging power Pb2 of power storage device 6-2. It is set to the value added with. Thereby, it is possible to indirectly suppress discharge power Pb1 of power storage device 6-1 within discharge power upper limit value Wout1 indicated by a chain line by suppressing power Po of driving force generation unit 2 within power upper limit value LMT. Thus, even if a delay occurs in the power distribution control as described above, the discharge power Pb1 of the power storage device 6-1 does not exceed the discharge power upper limit value Wout1.

  Next, the configuration of the HV-ECU 3 will be described in detail. FIG. 5 is a functional block diagram of HV-ECU 3 shown in FIG. Referring to FIG. 5, HV-ECU 3 includes a converter control unit 31 and a drive control unit 32.

  Converter control unit 31 receives discharge power upper limit values Wout1, Wout2 and charge power upper limit values Win1, Win2 of power storage devices 6-1 and 6-2 from battery ECU 4 (FIG. 1). Converter control unit 31 receives detection values of voltages Vb1, Vb2, and Vh from voltage sensors 12-1, 12-2, and 18 respectively, and detects currents Ib1 and Ib2 from current sensors 10-1 and 10-2, respectively. Receive value. Furthermore, converter control unit 31 receives torque target values TR1, TR2 and rotation speeds MRN1, MRN2 of motor generators MG1, MG2 from drive control unit 32.

  Based on the received signals, converter control unit 31 generates drive signals PWC1 and PWC2 for driving converters 8-1 and 8-2, and generates the generated drive signals PWC1 and PWC2, respectively. Output to converters 8-1, 8-2.

  The drive control unit 32 receives an accelerator opening signal ACC indicating an operation amount of the accelerator pedal from an accelerator opening sensor (not shown), and receives a vehicle speed signal VS indicating a vehicle speed from a vehicle speed sensor (not shown). In addition, drive control unit 32 receives state quantities SOC1 and SOC2 of power storage devices 6-1 and 6-2 from battery ECU 4. Further, drive control unit 32 includes voltage Vh, motor currents MCRT1 and MCRT2 of motor generators MG1 and MG2, rotor rotation angles θ1 and θ2, discharge power upper limit value Wout1 of storage device 6-1, charge power upper limit value Win1, and voltage Vb2. , Current Ib2, and rotational speeds MRN1 and MRN2. Motor currents MCRT1, MCRT2 and rotor rotation angles θ1, θ2 of motor generators MG1, MG2 are detected by sensors not shown.

  Based on the received signals, drive control unit 32 generates drive signals PWI1, PWI2 for driving motor generators MG1, MG2, respectively, and generates the generated drive signals PWI1, PWI2 respectively in inverter 20- 1 and 20-2. Further, drive control unit 32 outputs torque target values TR1 and TR2 and rotation speeds MRN1 and MRN2 calculated at the time of generation of drive signals PWI1 and PWI2 to converter control unit 31.

  FIG. 6 is a detailed functional block diagram of converter control unit 31 shown in FIG. Referring to FIG. 6, converter control unit 31 includes a target value setting unit 70, a voltage control unit 72-1, and a power control unit 72-2.

  The target value setting unit 70 calculates the required power PR of the driving force generation unit 2 based on the torque target values TR1, TR2 and the rotational speeds MRN1, MRN2 from the drive control unit 32 (FIG. 5), and the calculated request Based on the power PR, a target voltage VR indicating a target value of the voltage Vh between the main positive bus MPL and the main negative bus MNL is calculated.

  In addition, target value setting unit 70 is based on the calculated required power PR, and converter 8-2 is power-controlled within a range not exceeding discharge power upper limit value Wout2 and charge power upper limit value Win2 of power storage device 6-2. The target power PR2 indicating the target value of the charge / discharge power Pb2 is calculated. For example, when the required power PR of driving force generation unit 2 is equally shared by power storage devices 6-1 and 6-2, target value setting unit 70 sets 1/2 of the required power PR to the target power of converter 8-2. Calculated as PR2. Note that the target power PR2 of the converter 8-2 is not limited to 1/2 of the required power PR of the driving force generator 2, but considers the SOC, temperature, etc. of each of the power storage devices 6-1 and 6-2. Then, the burden distribution of power storage devices 6-1 and 6-2 may be determined, and target power PR2 may be calculated based on the distribution.

  Voltage control unit 72-1 includes subtraction units 74-1 and 78-1, PI control unit 76-1, and modulation unit 80-1. Subtraction unit 74-1 subtracts voltage Vh from target voltage VR and outputs the calculation result to PI control unit 76-1. The PI control unit 76-1 performs a proportional integration calculation with the deviation between the target voltage VR and the voltage Vh as an input, and outputs the calculation result to the subtraction unit 78-1.

  Subtraction unit 78-1 subtracts the output of PI control unit 76-1 from the reciprocal of the theoretical boost ratio of converter 8-1 indicated by voltage Vb1 / target voltage VR, and the calculation result is a duty command for converter 8-1. To the modulation unit 80-1. Modulation unit 80-1 generates drive signal PWC1 based on the duty command from subtraction unit 78-1 and a carrier wave (carrier wave) generated by an oscillation unit (not shown), and converts the generated drive signal PWC1 into converter 8. Output to -1.

  The power control unit 72-2 includes a multiplication unit 73, subtraction units 74-2 and 78-2, a PI control unit 76-2, and a modulation unit 80-2. Multiplier 73 calculates charging / discharging power Pb2 of power storage device 6-2 by multiplying current Ib2 by voltage Vb2.

  Subtraction unit 74-2 subtracts charge / discharge power Pb2 from target power PR2, and outputs the calculation result to PI control unit 76-2. The PI control unit 76-2 performs a proportional integration calculation with the deviation between the target power PR2 and the charge / discharge power Pb2 as an input, and outputs the calculation result to the subtraction unit 78-2.

  Subtraction unit 78-2 subtracts the output of PI control unit 76-2 from the reciprocal of the theoretical boost ratio of converter 8-2 indicated by voltage Vb2 / target voltage VR, and the calculation result is a duty command for converter 8-2. To the modulation unit 80-2. Modulation unit 80-2 generates drive signal PWC2 based on a duty command from subtraction unit 78-2 and a carrier wave (carrier wave) generated by an oscillation unit (not shown), and converts the generated drive signal PWC2 into converter 8. Output to -2.

  FIG. 7 is a detailed functional block diagram of the drive control unit 32 shown in FIG. Referring to FIG. 7, drive control unit 32 includes a torque calculation unit 90, a required power calculation unit 92, a power limit control unit 94, and an inverter control unit 96.

  Torque calculation unit 90 calculates torque target values TR1 and TR2 of motor generators MG1 and MG2 based on accelerator opening signal ACC, vehicle speed signal VS, and state quantities SOC1 and SOC2 of power storage devices 6-1 and 6-2. . Required power calculation unit 92 calculates the required power of each of motor generators MG1 and MG2 based on torque target values TR1 and TR2 and rotation speeds MRN1 and MRN2 of motor generators MG1 and MG2, and each of motor generators MG1 and MG2 The required power PR of the driving force generator 2 is calculated by adding the required power.

  The power limit control unit 94 sets a limit value of the required power PR, and when the required power PR exceeds the limit value, issues a torque reduction command to the torque calculation unit 90 so as to suppress the required power PR within the limit value. Output. Here, the limit value of required power PR is calculated by adding target power PR2 of converter 8-2 to discharge power upper limit value Wout1 of power storage device 6-1 during power running, and is stored during regeneration. It is calculated by adding the target power PR2 to the charging power upper limit value Win1 of the device 6-1. Instead of target power PR2 of converter 8-2, charging / discharging power Pb2 of power storage device 6-2 obtained by multiplying voltage Vb2 by current Ib2 may be added.

  Based on torque target values TR1 and TR2 calculated by torque calculation unit 90, motor currents MCRT1 and MCRT2 of motor generators MG1 and MG2, voltage Vh and rotor rotation angles θ1 and θ2, inverter control unit 96 generates motor generators MG1 and MG1. Each phase voltage command of MG2 is generated. The inverter control unit 96 generates drive signals PWI1, PWI2 based on the generated phase voltage commands and carrier waves (carrier waves) generated by an oscillation unit (not shown), and generates the generated drive signals PWI1, PWI2 is output to inverters 20-1 and 20-2, respectively.

  FIG. 8 is a flowchart for illustrating a control structure of HV-ECU 3 shown in FIG. The process shown in this flowchart is called from the main routine and executed at regular time intervals or when a predetermined condition is satisfied.

  Referring to FIG. 8, HV-ECU 3 requests required power PR for driving force generation unit 2 based on accelerator opening signal ACC, vehicle speed signal SV, and state quantities SOC1 and SOC2 of power storage devices 6-1 and 6-2. Is calculated (step S10). Then, HV-ECU 3 determines whether or not the calculated required power PR is larger than a limit value (Wout1 + PR2) obtained by adding target power PR2 of power storage device 6-2 to discharge power upper limit value Wout1 of power storage device 6-1. Is determined (step S20).

  If it is determined that required power PR is greater than the limit value (Wout1 + PR2) (YES in step S20), HV-ECU 3 limits the required power PR of driving force generation unit 2 to the limit value (Wout1 + PR2) (step S30). ).

  On the other hand, when it is determined in step S20 that required power PR is equal to or less than the limit value (Wout1 + PR2) (NO in step S20), HV-ECU 3 determines that required power PR is the charging power upper limit value Win1 of power storage device 6-1. It is determined whether or not it is smaller than a limit value (Win1 + PR2) obtained by adding the target power PR2 of the power storage device 6-2 (step S40).

  When it is determined that the required power PR is smaller than the limit value (Win1 + PR2) (YES in step S40), that is, it is determined that the required power PR is larger than the absolute value of the limit value (Win1 + PR2). Then, the HV-ECU 3 limits the required power PR of the driving force generator 2 to the limit value (Win1 + PR2) (step S50).

  Next, the HV-ECU 3 actually controls the driving force generator 2 to generate the required power PR (step S60). In addition to the control of driving force generation unit 2, HV-ECU 3 also controls converters 8-1, 8-2. Specifically, HV-ECU 3 calculates target power PR2 of converter 8-2 based on required power PR (power distribution control) (step S70). Further, the HV-ECU 3 calculates a target voltage VR indicating a target value of the voltage Vh between the main positive bus MPL and the main negative bus MNL.

  Then, HV-ECU 3 performs voltage control on converter 8-1 so that voltage Vh becomes target voltage VR, and converter 8-2 so that charge / discharge power Pb2 of power storage device 6-2 becomes target power PR2. Is subjected to power control (step S90).

  As described above, in the first embodiment, converter 8-1 is voltage-controlled so that voltage Vh becomes target voltage VR. Converter 8-2 is power-controlled such that charge / discharge power Pb2 of power storage device 6-2 becomes target power PR2. And since HV-ECU3 restrict | limits the request | requirement power PR with respect to the driving force generation | occurrence | production part 2 to the value which added the charging / discharging electric power of the electrical storage apparatus 6-2 to the electric power upper limit value with respect to the electrical storage apparatus 6-1. 1 charging / discharging power Pb1 does not exceed the power upper limit value (Wout1, Win1) for power storage device 6-1. Therefore, according to the first embodiment, the input / output power of each power storage device 6-1, 6-2 can be controlled within the limit value even if the output rotation speed of driving force generator 2 changes suddenly.

[Embodiment 2]
In the first embodiment, voltage control is performed by limiting power Po of driving force generation unit 2 to a value obtained by adding charging / discharging power of power storage device 6-2 to the power upper and lower limit values of power storage device 6-1. The upper and lower limits of the charge / discharge power of power storage device 6-1 corresponding to converter 8-1 are guaranteed. In this Embodiment 2, the policy for ensuring more reliably the upper and lower limits of the charging / discharging electric power of the electrical storage apparatus 6-1 is shown.

  FIG. 9 is a diagram for illustrating the concept of power distribution between motor generators MG1 and MG2 and power storage devices 6-1 and 6-2 in the second embodiment. In the following, it is assumed that motor generator MG1 functions as a generator that can generate electric power using engine output, and motor generator MG2 functions as an electric motor that drives drive wheels.

  Referring to FIG. 9, “MG1” indicates the power of motor generator MG1, and a negative value indicates that power is generated using the engine output. “MG2” indicates the power of the motor generator MG2. Moreover, in FIG. 9, the upper stage shows a state before slipping, and the lower stage shows a state during slipping. For comparison, the power limit control according to the second embodiment is shown in the middle part of the figure when slip is not performed (conventional equivalent).

  Before the occurrence of slip (when non-slip), motor generator MG1 generates power using the engine output. The output of motor generator MG2 is larger than the generated power of motor generator MG1, and the shortage is taken out from power storage devices 6-1 and 6-2 (that is, power storage devices 6-1 and 6-2 are in a discharged state).

  When the drive wheel slip occurs, as described above, the rotational speed of the motor generator MG2 increases rapidly immediately after the slip occurs, and the torque of the motor generator MG2 is reduced to prevent the motor generator MG2 from over-rotating. Thereby, the output of motor generator MG2 decreases. Then, the power generated by motor generator MG1 is not consumed by motor generator MG2 in driving force generation unit 2, and a situation occurs where power flows from driving force generation unit 2 to power supply unit 1.

  At this time, the output change of the driving force generation unit 2 may be immediately reflected in the power distribution control of the power storage devices 6-1 and 6-2 in the power source unit 1. Due to a delay in signal transmission or the like, a situation occurs in which the output change of the driving force generator 2 is not immediately reflected in the power distribution control of the power storage devices 6-1 and 6-2. As a result, the power from the driving force generation unit 2 and the power storage device 6-2 flows into the power storage device 6-1, and the charging power Pb1 of the power storage device 6-1 has exceeded the charging power upper limit value Win1. FIG. 9 middle).

  Therefore, in the second embodiment, when the rotational speed of motor generator MG2 that drives the driving wheel (or the rotational speed of the driving wheel itself) suddenly changes, charging / discharging of power storage device 6-2 is performed. The converter 8-2 is controlled so that the electric power becomes zero, and the charging / discharging electric power of the power storage device 6-1 is prevented from becoming excessive (lower stage in FIG. 9).

  FIG. 10 is a detailed functional block diagram of the converter control unit according to the second embodiment. Referring to FIG. 10, converter control unit 31A further includes a slip / grip determination unit 82 in the configuration of converter control unit 31 in the first embodiment shown in FIG.

  Slip / grip determination unit 82 receives rotation speed MRN2 of motor generator MG2 that drives the drive wheel, and based on the received change in rotation speed MRN2, whether slip determination, grip determination, or slip / grip state change has occurred. Make a decision. Note that the slip / grip determination unit 82 may simply detect a sudden change in the rotational speed MRN2 based on the rotational speed MRN2. When a sudden change in the rotational speed MRN2 is detected, the slip / grip determination unit 82 notifies the target value setting unit 70 to that effect.

  When target value setting unit 70 receives notification from motor-slip / grip determination unit 82 that rotation speed MRN2 of motor generator MG2 has suddenly changed, target value setting unit 70 sets target power PR2 of power storage device 6-2 to zero. Other functions of the target value setting unit 70 are the same as those in the first embodiment. Other functions of converter control unit 31A are the same as those of converter control unit 31 in the first embodiment, and the configuration of drive control unit 32 is the same as that of the first embodiment.

  FIG. 11 is a flowchart for illustrating a control structure of HV-ECU 3A in the second embodiment. The process shown in this flowchart is also called and executed from the main routine at regular time intervals or when a predetermined condition is satisfied.

  Referring to FIG. 11, this flowchart further includes steps S72 and S74 in the flowchart shown in FIG. That is, following step S70, HV-ECU 3A determines whether or not rotation speed MRN2 of motor generator MG2 that drives the drive wheels has suddenly changed (step S72). When HV-ECU 3A detects a sudden change in rotational speed MRN2 (YES in step S72), HV-ECU 3A sets target power PR2 of converter 8-2 to zero. Thereafter, the HV-ECU 3A advances the process to step S80, and calculates the target voltage VR.

  As described above, in the second embodiment, when a sudden change in rotation speed MRN2 (which may be the rotation speed of the drive wheel itself) of motor generator MG2 for driving the drive wheel is detected, converter 8- Since the target power PR2 of 2 is set to zero, the charge / discharge power Pb2 of the power storage device 6-2 becomes zero. Therefore, according to the second embodiment, it is possible to reliably prevent the input / output power of power storage device 6-1 from exceeding the upper and lower limit values.

  In the first and second embodiments, the converter 8-2 is controlled based on the target power PR2 of the power storage device 6-2. However, the converter 8-2 is controlled based on the target power PR2. You may control.

  FIG. 12 is a functional block diagram of the converter control unit when current control is performed on converter 8-2 based on target power PR2. Although FIG. 12 shows a configuration corresponding to converter control unit 31 in the first embodiment, the same configuration can be adopted for converter control unit 31A in the second embodiment.

  Referring to FIG. 12, converter control unit 31B further includes division unit 84 in the configuration of converter control unit 31 shown in FIG. 6, and includes current control unit 72-2A instead of power control unit 72-2. Including.

  Dividing unit 84 divides target power PR2 of converter 8-2 from target value setting unit 70 by voltage Vb2 of power storage device 6-2, and outputs the calculation result to current control unit 72-2A as target current IR2. .

  The current control unit 72-2A has a configuration that does not include the multiplication unit 73 in the configuration of the power control unit 72-2 illustrated in FIG. Subtraction unit 74-2 subtracts current Ib2 from target current IR2, and outputs the calculation result to PI control unit 76-2. Then, PI control unit 76-2 performs a proportional integration calculation with the deviation between target current IR2 and current Ib2 as an input, and outputs the calculation result to subtraction unit 78-2. The other configuration of converter control unit 31B is the same as that of converter control unit 31.

  In the above, the control in the HV-ECU 3, 3A is actually performed by a CPU (Central Processing Unit), and the CPU reads a program including each step of the flowcharts shown in FIGS. Memory), and the read program is executed to execute processing according to the flowcharts shown in FIGS. Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program having the steps of the flowcharts shown in FIGS.

  In each of the above embodiments, the converter 8-1 is voltage-controlled and the converter 8-2 is power-controlled (current control). However, the converter 8-2 is voltage-controlled and the converter 8-1 is controlled. May be power controlled (current controlled).

  In the above description, the power supply unit 1 includes two power storage devices and two converters corresponding to them. However, the power supply unit 1 includes three or more power storage devices and converters corresponding to them. It may be included. In this case, one of the converters is voltage-controlled and the other converters are power-controlled. As a configuration corresponding to the first embodiment, the driving force is added to the value obtained by adding the charge / discharge power of each power storage device corresponding to the power control converter to the power upper and lower limit values for the power storage device corresponding to the voltage control converter. The required power PR for the generator 2 may be limited. Further, as a configuration corresponding to the second embodiment, when a sudden change in the rotational speed of the drive wheel is detected, the target power of the power storage device corresponding to the converter to be power controlled may be set to zero.

  In the above, the converters 8-1 and 8-2 and the inverters 20-1 and 20-2 are controlled by the HV-ECUs 3 and 3A. However, the ECUs are separately configured for converter control and inverter control. May be. Or you may comprise battery ECU4 and HV-ECU3,3A by one ECU.

  Further, the present invention can be applied to all electric vehicles such as a hybrid vehicle including an engine as a power source, an electric vehicle that runs only by electric power without an engine, and a fuel cell vehicle further including a fuel cell as a power source.

  In the above description, HV-ECUs 3 and 3A correspond to the “control unit” in the present invention, and power storage devices 6-1 and 6-2 correspond to “first power storage device” and “second power supply” in the present invention, respectively. Corresponds to “power storage device”. Converters 8-1 and 8-2 correspond to “first converter” and “second converter” in the present invention, respectively, and slip / grip determination unit 82 corresponds to “determination unit” in the present invention. To do.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is an overall block diagram of an electric vehicle according to Embodiment 1 of the present invention. It is a figure for demonstrating the view of the power limiting control by HV-ECU shown in FIG. It is the 1st figure which showed the time transition of the charging / discharging electric power of the electrical storage apparatus at the time of slip generation | occurrence | production. It is the 2nd figure which showed the time transition of the charging / discharging electric power of the electrical storage apparatus at the time of slip generation | occurrence | production. It is a functional block diagram of HV-ECU shown in FIG. It is a detailed functional block diagram of the converter control part shown in FIG. FIG. 6 is a detailed functional block diagram of a drive control unit shown in FIG. 5. 2 is a flowchart for illustrating a control structure of the HV-ECU shown in FIG. FIG. 11 is a diagram for explaining a concept of power distribution between a motor generator and a power storage device in a second embodiment. FIG. 10 is a detailed functional block diagram of a converter control unit in a second embodiment. 6 is a flowchart for illustrating a control structure of an HV-ECU in a second embodiment. It is a functional block diagram of a converter control part in the case of carrying out current control of a converter based on target electric power.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Power supply part, 2 Driving force generation part, 3,3A HV-ECU, 4 Battery ECU, 6-1, 6-2 Power storage device, 8-1, 8-2 converter, 10-1, 10-2 Current sensor, 12-1, 12-2, 18 Voltage sensor, 20-1, 20-2 Inverter, 22 Power transmission mechanism, 24 Drive shaft, 31, 31A Converter control unit, 32 Drive control unit, 70 Target value setting unit, 72- 1 voltage control unit, 72-2 power control unit, 72-2A current control unit, 73 multiplication unit, 74-1, 74-2, 78-1, 78-2 subtraction unit, 76-1, 76-2 PI control Unit, 80-1, 80-2 modulation unit, 82 slip / grip determination unit, 84 division unit, 90 torque calculation unit, 92 required power calculation unit, 94 power limit control unit, 96 inverter control unit, 100 electric vehicle, MPL main Positive bus, MNL main negative bus, C capacitor, MG1, MG2 motor generator, PL1, PL2 positive line, NL1, NL2 negative line.

Claims (7)

A driving force generator configured to generate a driving force of the vehicle by an electric motor;
A power supply unit capable of transmitting and receiving electric power via the driving force generation unit and a power line;
A control unit for controlling the driving force generation unit and the power supply unit,
The power supply unit is
Chargeable and dischargeable first and second power storage devices;
A first converter provided between the first power storage device and the power line;
A second converter provided between the second power storage device and the power line,
The controller is
A power calculation unit for calculating required power for the driving force generation unit;
A voltage control unit for controlling the first converter so that the voltage of the power line becomes a predetermined target voltage;
A power control unit for controlling the second converter so that the charge / discharge power of the second power storage device becomes a predetermined target power;
An electric vehicle comprising: a power limit control unit that limits the required power to a value obtained by adding charge / discharge power of the second power storage device to a power limit value for the first power storage device. The control unit further includes a determination unit that determines whether or not the output rotational speed of the driving force generation unit has suddenly changed,
The power control unit controls the second converter so that charging / discharging power of the second power storage device becomes substantially zero when the determination unit determines that the output rotation speed has suddenly changed. Item 4. The electric vehicle according to Item 1.   The electric vehicle according to claim 1, wherein the power control unit controls a current of the second converter so that a charge / discharge power of the second power storage device becomes the target power. An electric vehicle control method comprising:
The electric vehicle is
A driving force generator configured to generate a driving force of the vehicle by an electric motor;
A power supply unit capable of transmitting and receiving power via the driving force generation unit and a power line;
The power supply unit is
Chargeable and dischargeable first and second power storage devices;
A first converter provided between the first power storage device and the power line;
A second converter provided between the second power storage device and the power line,
The control method is:
Calculating a required power for the driving force generator;
Controlling the first converter so that the voltage of the power line becomes a predetermined target voltage;
Controlling the second converter so that the charge / discharge power of the second power storage device becomes a predetermined target power;
And a step of limiting the required power to a value obtained by adding charge / discharge power of the second power storage device to a power limit value for the first power storage device. Further comprising the step of determining whether or not the output rotational speed of the driving force generator has suddenly changed,
When it is determined that the output rotation speed has suddenly changed, in the step of controlling the second converter, the second converter is controlled so that the charge / discharge power of the second power storage device becomes substantially zero. The method for controlling an electric vehicle according to claim 4.   6. The step of controlling the second converter, wherein the current of the second converter is controlled so that charge / discharge power of the second power storage device becomes the target power. Method for controlling an electric vehicle.   The computer-readable recording medium which recorded the program for making a computer perform the control method of the electric vehicle of any one of Claims 4-6.

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