JP6063298B2 - Electric power system and fuel cell vehicle - Google Patents

Description

  The present invention relates to a power system including a fuel cell and a power storage device arranged in parallel, a first DC / DC converter that transforms the output voltage of the fuel cell, and a second DC / DC converter that transforms the output voltage of the power storage device, and The present invention relates to a fuel cell vehicle.

  In Patent Document 1, when there are a plurality of components that cause power loss, provision of a fuel cell system and a motor driving method capable of driving a motor while suppressing power loss of the entire system is contemplated. ([0007]). For this reason, in Patent Document 1, at least one power loss of the motor 15, the first converter 11, the second converter 12, and the inverter 14 is minimized under the operating conditions (motor torque and rotational speed) required for the motor 15. The input voltage of the inverter to be determined is determined and output as the required voltage of the inverter (summary). Specifically, when determining the step-up rate of the first converter 11 or the second converter 12, a map that defines the relationship between the combination of the motor torque T and the rotation speed fN and the inverter required voltage Vin is used (FIG. 3). -FIG. 7, FIG. 9).

International Publication No. 2011/004487 Pamphlet

  As described above, in Patent Document 1, when determining the step-up rate of the first converter 11 or the second converter 12, a map that defines the relationship between the combination of the motor torque T and the rotational speed fN, the inverter required voltage Vin, and the like. (FIGS. 3 to 7 and FIG. 9). In other words, when determining the step-up rate of the first converter 11 or the second converter 12, the inverter necessary voltage Vin and the like are uniquely specified from the torque T and the rotational speed fN.

  However, when both the first converter 11 and the second converter 12 are operating at the same time, the energy efficiency (power efficiency) or power loss in the entire system changes depending on the outputs of the first converter 11 and the second converter 12. To do. In Patent Document 1, this point has not been studied, and there is still room for improvement in terms of energy efficiency (power efficiency) or power loss.

  The present invention has been made in consideration of such problems, and an object thereof is to provide an electric power system and a fuel cell vehicle capable of improving the energy efficiency or electric power efficiency as a whole.

  A power system according to the present invention includes a DC power source having a fuel cell and a power storage device arranged in parallel, a motor, and a DC power source disposed between the DC power source and the motor. An inverter that converts AC power and supplies the motor, a first DC / DC converter that is disposed between the fuel cell and the inverter and boosts the output voltage of the fuel cell, and between the power storage device and the inverter And a second DC / DC converter that steps up and down the output voltage of the power storage device, and a control device that controls the first DC / DC converter and the second DC / DC converter, wherein the control device is The required motor voltage specified on the basis of the motor rotational speed and the motor torque in consideration of the power efficiency of the motor is set to the first DC / DC converter. Calculating the over data and values obtained by weighting in accordance with the comparison result parameter related to the passing electric power or electric power passing through the first 2DC / DC converter as a target input voltage of the inverter.

  According to the present invention, the required motor voltage specified based on the motor speed and the motor torque in consideration of the power efficiency of the motor is related to the passing power or the passing power of the first DC / DC converter and the second DC / DC converter. A value weighted according to the comparison result of the parameter to be calculated is calculated as the target input terminal voltage of the inverter (that is, the target input voltage to the motor). Thereby, it becomes possible to calculate the target input terminal voltage of the inverter reflecting the influence of the passing power of the first DC / DC converter and the second DC / DC converter. Accordingly, it is possible to improve the energy efficiency of the entire power system.

  As the parameters related to the passing power, any parameters can be adopted as long as they follow the fluctuation of the passing power, such as passing current, passing power or estimated value of passing current, air pump rotation speed, air pressure, etc. It is.

  The control device compares the passing electric power of the first DC / DC converter and the second DC / DC converter or a parameter related to the passing electric power, and compares the outlet end current or the inlet of the first DC / DC converter and the second DC / DC converter. You may carry out using an end current. Thereby, it is possible to easily compare the passing power of the first DC / DC converter and the second DC / DC converter.

The control device sets a plurality of target input terminal voltage maps that define the relationship between the motor rotation speed and the motor torque and the target input terminal voltage, and the comparison result of the parameters related to the passing power or the passing power The map may be switched in accordance with the map , and the target input terminal voltage corresponding to the motor rotational speed and the motor torque may be acquired using the switched map . As a result, the target input terminal voltage can be directly calculated from the motor rotation speed and the motor torque, so that calculation of the required motor voltage can be omitted when the motor is driven. Accordingly, it is possible to improve the calculation speed or reduce the calculation load.

  Alternatively, the control device sets one target input terminal voltage map that defines the relationship between the motor rotational speed and the motor torque and the target input terminal voltage when power is supplied only from the fuel cell. The temporary target input terminal voltage, which is the target input terminal voltage in the map, for both the case where electric power is supplied only from the fuel cell and the case where electric power is supplied from both the fuel cell and the power storage device, The target input terminal voltage of the inverter may be calculated by correcting with a correction coefficient corresponding to the passing power or a comparison result of parameters related to the passing power. This eliminates the need to prepare a target input terminal voltage map for each comparison result. Accordingly, the storage capacity for the map can be reduced, and the map can be prepared relatively easily.

  The control device is capable of direct connection processing for supplying power from the fuel cell to the inverter without boosting the first DC / DC converter, and when the motor rotation speed and the motor torque are constant, Compared with the case where the first DC / DC converter has a smaller passing power or a parameter related to the passing power than the second DC / DC converter, the first DC / DC converter has the first DC / DC converter rather than the second DC / DC converter. May be earlier when the passing power or the parameter related to the passing power is larger. Thereby, energy efficiency can be improved in connection with the direct connection process.

  A fuel cell vehicle according to the present invention includes the power system described above, and the motor is a traveling motor. As a result, it is possible to provide a fuel cell vehicle having excellent power efficiency.

  According to the present invention, the required motor voltage specified based on the motor speed and the motor torque in consideration of the power efficiency of the motor is related to the passing power or the passing power of the first DC / DC converter and the second DC / DC converter. A value weighted according to the comparison result of the parameter to be calculated is calculated as the target input terminal voltage of the inverter (that is, the target input voltage to the motor). Thereby, it becomes possible to calculate the target input terminal voltage of the inverter reflecting the influence of the passing power of the first DC / DC converter and the second DC / DC converter. Accordingly, it is possible to improve the energy efficiency of the entire power system.

1 is a schematic overall configuration diagram of a fuel cell vehicle according to an embodiment of the present invention. FIG. 2 is a schematic circuit diagram showing a configuration example of a boost converter for a fuel cell stack (hereinafter referred to as “FC-VCU”) in the embodiment. 3 is a schematic circuit diagram illustrating a configuration example of a battery buck-boost converter (hereinafter referred to as “BAT-VCU”) in the embodiment. FIG. The flowchart of the basic control in the electronic control apparatus in the said embodiment is shown. 6 is a flowchart for calculating a system load in the embodiment (details of S2 in FIG. 4). It is a figure which shows the relationship between the present motor rotation speed and motor expected power consumption. It is a flowchart which controls an inverter input terminal voltage. 8 is a flowchart for selecting a plurality of target voltage maps (details of S23 in FIG. 7). It is an example of the reference map which prescribed | regulated the relationship between the combination of a motor rotation speed and a motor torque, and a request | required motor voltage. It is a figure which shows an example of the 1st map which prescribed | regulated the relationship between the combination of the said motor rotation speed and the said motor torque, and the target value (target input terminal voltage) of an inverter input terminal voltage. It is a figure which shows an example of the 2nd map which prescribed | regulated the relationship between the combination of the said motor rotation speed and the said motor torque, and the said target input terminal voltage. It is a figure which shows an example of the 3rd map which prescribed | regulated the relationship between the combination of the said motor rotation speed and the said motor torque, and the said target input terminal voltage. It is the figure which showed the relationship between the passing electric power of the said FC-VCU, and a power loss for every output voltage of the said FC-VCU. It is a flowchart which shows the setting method of each area | region in the said 1st map. It is a figure which shows an example of the relationship between the output voltage of the said fuel cell, and a 2nd motor output threshold value. It is a figure for demonstrating the power efficiency of the said FC-VCU and the said BAT-VCU. It is a figure which shows an example of the time chart at the time of using the various control which concerns on the said embodiment. It is a flowchart (detail of S5 of FIG. 4) of motor torque control. FIG. 9 is a flowchart for selecting a plurality of target voltage maps as a modification of FIG. 8 (details of S23 in FIG. 7). It is a figure which shows an example of the 4th map which prescribed | regulated the relationship between the combination of the said motor rotation speed and the said motor torque, and the said target input terminal voltage. It is a figure which shows an example of the 5th map which prescribed | regulated the relationship between the combination of the said motor rotation speed and the said motor torque, and the said target input terminal voltage. It is a flowchart which controls an inverter input terminal voltage as a modification of FIG. It is a figure which shows an example of the map for setting a correction coefficient. It is a figure which shows an example of the time chart at the time of using the various control which concerns on the modification of FIG.

1. Explanation of overall configuration [1-1. overall structure]
FIG. 1 is a schematic overall configuration diagram of a fuel cell vehicle 10 (hereinafter referred to as “FC vehicle 10” or “vehicle 10”) according to an embodiment of the present invention. The FC vehicle 10 includes a fuel cell system 12 (hereinafter referred to as “FC system 12”), a travel motor 14 (hereinafter referred to as “motor 14”), and an inverter 16.

  The FC system 12 includes a fuel cell unit 20 (hereinafter referred to as “FC unit 20”), a high voltage battery 22 (hereinafter also referred to as “battery 22”) (power storage device), a boost converter 24, and a step-up / down converter 26. And an auxiliary machine 28 and an electronic control unit 30 (hereinafter referred to as “ECU 30”).

[1-2. Drive system]
The motor 14 of this embodiment is a three-phase AC brushless type. The motor 14 generates a driving force based on the electric power supplied from the FC unit 20 and the battery 22, and rotates the wheels 34 through the transmission 32 by the driving force. Further, the motor 14 outputs electric power (regenerative power Preg) [W] generated by performing regeneration to the battery 22 or the like. The current of each phase (U phase, V phase, W phase) of the motor 14 is detected by current sensors 36u, 36v, 36w. Alternatively, only two phases of the three phases may be detected, and the remaining one-phase current may be detected from these currents.

  The inverter 16 has a three-phase bridge configuration and performs DC-AC conversion. More specifically, the inverter 16 converts direct current into three-phase alternating current and supplies it to the motor 14, while supplying direct current after alternating current-direct current conversion accompanying the regenerative operation to the battery 22 and the like through the step-up / down converter 26. . The motor 14 and the inverter 16 are collectively referred to as a load 40.

[1-3. FC unit 20]
The FC unit 20 includes a fuel cell stack 50 (hereinafter referred to as “FC stack 50” or “FC50”) and its peripheral components. The FC stack 50 has a structure in which, for example, fuel cells formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode from both sides are stacked. The peripheral parts include an anode system that supplies and discharges hydrogen (fuel gas) to and from the anode of the FC stack 50, and a cathode system that supplies and discharges air (oxidant gas) containing oxygen to the cathode of the FC stack 50. A cooling system for cooling the FC stack 50, and a cell voltage monitor. As will be described later, some of the peripheral parts are also included in the auxiliary machine 28. As shown in FIG. 1, a backflow prevention diode 52 is disposed between the FC unit 20 (FC50) and the inverter 16 in parallel with the boost converter 24.

  The output voltage of the FC 50 (hereinafter referred to as “FC voltage Vfc”) is detected by the voltage sensor 54, and the output current of the FC 50 (hereinafter referred to as “FC current Ifc”) is detected by the current sensor 56, both of which are sent to the ECU 30. Is output.

[1-4. High voltage battery 22]
The battery 22 is a power storage device (energy storage) including a plurality of battery cells. For example, a lithium ion secondary battery, a nickel hydride secondary battery, or a capacitor can be used. In this embodiment, a lithium ion secondary battery is used. The output voltage (hereinafter referred to as “battery voltage Vbat”) [V] of the battery 22 is detected by the voltage sensor 60, and the output current (hereinafter referred to as “battery current Ibat”) [A] of the battery 22 is detected by the current sensor 62. And output to the ECU 30, respectively. The ECU 30 calculates the remaining capacity (SOC) [%] of the battery 22 based on the battery voltage Vbat and the battery current Ibat.

[1-5. Boost Converter 24]
The boost converter 24 is a boost chopper type voltage converter (DC / DC converter) that boosts the output voltage (FC voltage Vfc) of the FC 50 and supplies the boosted voltage to the inverter 16. Boost converter 24 is arranged between FC 50 and inverter 16. In other words, one of the boost converters 24 is connected to the primary side 1Sf having the FC 50, and the other is connected to the secondary side 2S that is a connection point between the battery 22 and the load 40. Hereinafter, boost converter 24 is also referred to as “FC-VCU 24” in the sense of a voltage control unit for FC 50.

  FIG. 2 is a schematic circuit diagram illustrating a configuration example of the FC-VCU 24. The FC-VCU 24 includes an inductor 70, a switching element 72, a diode 74, and a smoothing capacitor 76, and boosts the FC voltage Vfc by switching (duty control) the switching element 72 through the ECU 30. The boosted voltage becomes the input terminal voltage of the inverter 16 (hereinafter referred to as “inverter input terminal voltage Vinv” or “input terminal voltage Vinv”). The inverter input terminal voltage Vinv is detected by a voltage sensor 78 (FIG. 1). Further, the outlet end current of the FC-VCU 24 (hereinafter referred to as “outlet end current Ifcvcu”) is detected by the current sensor 80.

  When the switching element 72 is maintained in the off state (open state), the power from the FC 50 (hereinafter referred to as “FC power Pfc”) is not boosted through the wiring having the diode 52 or the wiring having the inductor 70 and the diode 74. Supply is possible. Hereinafter, a state in which the FC power Pfc is supplied without boosting is referred to as a “direct connection state”, an operation for realizing the direct connection state is referred to as a “direct connection process”, and a process for realizing the direct connection state is referred to as a “direct connection process”. That's it.

  In the direct connection state, boosting by the FC-VCU 24 is not performed, and therefore the inverter input terminal voltage Vinv becomes equal to the FC voltage Vfc. More precisely, in the direct connection state, the input terminal voltage Vinv is a value obtained by subtracting the voltage drop due to the diodes 52 and 74 from the FC voltage Vfc, but in the following, the input terminal voltage Vinv is substantially equal to the FC voltage Vfc. Explanation will be made assuming that they are equal.

  Note that the diode 74 operates in the same way as the diode 52 for direct connection and prevention of backflow, so the diode 52 may be omitted.

[1-6. Buck-Boost Converter 26]
The step-up / down converter 26 is a step-up / down chopper type voltage converter (DC / DC converter). That is, the step-up / step-down converter 26 boosts the output voltage (battery voltage Vbat) of the battery 22 and supplies the boosted voltage to the inverter 16, and at the same time as the regenerative voltage of the motor 14 (hereinafter referred to as “regenerative voltage Vreg”) or the FC voltage Vfc. The inverter input terminal voltage Vinv can be stepped down and supplied to the battery 22. The step-up / down converter 26 is arranged between the battery 22 and the inverter 16. In other words, one of the buck-boost converters 26 is connected to the primary side 1Sb where the battery 22 is located, and the other is connected to the secondary side 2S which is a connection point between the FC 50 and the load 40. Hereinafter, the step-up / step-down converter 26 is also referred to as “BAT-VCU 26” in the sense of the voltage control unit for the battery 22.

  FIG. 3 is a schematic circuit diagram showing a configuration example of the BAT-VCU 26. The BAT-VCU 26 includes an inductor 90, switching elements 92 and 94, diodes 96 and 98 connected in parallel to the switching elements 92 and 94, and smoothing capacitors 100 and 102, respectively.

  At the time of boosting (during power running using the battery 22), the ECU 30 turns off the switching element 94 and switches the switching element 92 (duty control) to boost the battery voltage Vbat. The boosted voltage becomes the inverter input terminal voltage Vinv.

  At the time of step-down (during regeneration or power running without using the battery 22), the ECU 30 turns off the switching element 92, and the switching element 94 is switched (duty control) so that the inverter input terminal voltage Vinv is changed to the battery voltage. Step down to Vbat.

  As described above, the inverter input terminal voltage Vinv is detected by the voltage sensor 78 (FIG. 1). Further, the outlet end current of the BAT-VCU 26 (hereinafter referred to as “outlet end current Ibatvcu”) is detected by the current sensor 104.

  The BAT-VCU 26 can also realize a direct connection state similar to that of the FC-VCU 24, and the BAT-VCU 26 can perform a direct connection operation or a direct connection process.

  In the present embodiment, the ECU 30 controls the FC-VCU 24 and the BAT-VCU 26, whereby the FC power Pfc from the FC unit 20 and the power supplied from the battery 22 (hereinafter referred to as “battery power Pbat”) [W]. And the supply destination of the regenerative power Preg from the motor 14 is controlled.

[1-7. Auxiliary machine 28]
As the auxiliary machine 28, for example, at least one of an air pump, a water pump, an air conditioner, a step-down DC-DC converter, a low voltage battery, an accessory, a radiator fan, and an ECU 30 can be included.

  The air pump supplies air to the FC 50. The water pump circulates water as a refrigerant for cooling the FC50. The air conditioner adjusts the temperature in the vehicle 10 and the like. The step-down DC-DC converter steps down the voltage at the primary side 1Sb of the step-up / step-down converter 26 (BAT-VCU 26) and supplies it to the low-voltage battery, the accessory, the radiator fan, and the ECU 30. The low voltage battery is a battery (for example, a 12V battery) for operating a low voltage device. The accessories include devices such as audio devices and navigation devices. The radiator fan is a fan for cooling the refrigerant circulated by the water pump in the radiator.

  The air pump, the water pump, and the radiator fan among the auxiliary machines 28 are also included in the FC unit 20.

[1-8. ECU 30]
The ECU 30 controls the motor 14, the inverter 16, the FC unit 20, the battery 22, the boost converter 24, the step-up / down converter 26, and the auxiliary machine 28 via the communication line 106 (FIG. 1). In the control, the ECU 30 executes a program stored in the storage unit. Further, the ECU 30 uses detection values of various sensors such as voltage sensors 54, 60, 78, current sensors 36u, 36v, 36w, 56, 62, 80, 104 and the like.

  The various sensors here include an opening sensor 110 and a motor rotation speed sensor 112 (FIG. 1) in addition to the above sensors. The opening sensor 110 detects the opening θp [degree] of the accelerator pedal 114. The rotation speed sensor 112 detects the rotation speed of the motor 14 (hereinafter referred to as “motor rotation speed Nmot” or “rotation speed Nmot”) [rpm]. The ECU 30 detects the vehicle speed V [km / h] of the FC vehicle 10 using the rotation speed Nmot. Further, the ECU 30 is connected to a main switch 116 (hereinafter referred to as “main SW 116”). The main SW 116 switches whether power can be supplied from the FC unit 20 and the battery 22 to the motor 14, and can be operated by the user.

  The ECU 30 includes a microcomputer and has an input / output interface such as an A / D converter and a D / A converter as necessary. The ECU 30 is not limited to only one ECU, but can be composed of a plurality of ECUs for each of the motor 14, the FC unit 20, the battery 22, the boost converter 24, the step-up / down converter 26, and the auxiliary machine 28.

  The ECU 30 determines the load required for the FC system 12 as a whole of the FC vehicle 10 determined based on the input (load request) from various switches and various sensors in addition to the state of the FC stack 50, the state of the battery 22 and the state of the motor 14. Therefore, the load to be borne by the FC stack 50, the load to be borne by the battery 22, and the distribution (sharing) of the load to be borne by the regenerative power source (motor 14) are determined while arbitrating, and the motor 14, inverter 16, Commands are sent to the FC unit 20, the battery 22, the boost converter 24 and the step-up / down converter 26.

2. Control of this Embodiment Next, the control in ECU30 is demonstrated.

[2-1. Basic control]
FIG. 4 shows a flowchart of basic control in the ECU 30. If the main SW 116 is not on (S1: NO), the ECU 30 does not start. If the main SW 116 is on (S1: YES), the ECU 30 is activated and proceeds to step S2. In step S2, the ECU 30 calculates a load (system load Psys) [W] required for the FC system 12.

  In step S3, the ECU 30 performs energy management of the FC system 12. The energy management here is a process for controlling the operation of each part of the FC system 12. For example, in energy management, how to allocate the system load Psys to each power source (the battery 22 and / or FC50 during power running and the motor 14 (and FC50 if applicable) during regeneration). Set. In addition, the generation amount of FC 50 (FC power Pfc), the operation of peripheral devices of FC 50, the operation of each converter 24, 26, and the like are set with the allocation.

  In step S4, the ECU 30 controls peripheral devices of the FC stack 50 (FC power generation control) based on the calculation result of energy management in step S3. The peripheral devices referred to here include, for example, various valves (circulation valve, back pressure valve, etc.) of the FC unit 20 in addition to the air pump, the water pump, and the radiator fan.

  In step S5, the ECU 30 performs torque control (motor torque control) of the motor 14 based on the calculation result of energy management in step S3. The motor torque control here includes control of the inverter 16.

  If the main SW 116 is not off in step S6 (S6: NO), the process returns to step S2. When the main SW 116 is off (S6: YES), the ECU 30 stops and ends the process.

[2-2. Calculation of system load Psys]
FIG. 5 shows a flowchart for calculating the system load Psys (details of S2 in FIG. 4). In step S <b> 11, the ECU 30 reads the opening degree θp of the accelerator pedal 114 from the opening degree sensor 110. In step S <b> 12, the ECU 30 reads the rotational speed Nmot of the motor 14 from the rotational speed sensor 112.

  In step S13, the ECU 30 calculates the expected power consumption Pmot_cons [W] of the motor 14 based on the opening degree θp and the rotation speed Nmot. Specifically, in the map shown in FIG. 6, the relationship between the rotational speed Nmot and the predicted power consumption Pmot_cons is stored for each opening θp. For example, when the opening degree θp is θp1, the characteristic 120 is used. Similarly, when the opening degree θp is θp2, θp3, θp4, θp5, and θp6, the characteristics 122, 124, 126, 128, and 130 are used, respectively. The relationship between the opening degrees θ1 to θ6 is θp1 <θp2 <θp3 <θp4 <θp5 <θp6. Then, after specifying the characteristic indicating the relationship between the rotational speed Nmot and the predicted power consumption Pmot_cons based on the opening θp, the predicted power consumption Pmot_cons corresponding to the rotational speed Nmot is specified.

  In step S <b> 14, the ECU 30 reads the current operation status from the auxiliary machine 28. The auxiliary machine 28 includes, for example, a high-voltage auxiliary machine including the air pump, the water pump and the air conditioner, a low-voltage battery including the low-voltage battery, the accessory, the radiator fan and the ECU 30. Auxiliary machines are included. For example, if it is the said air pump and the said water pump, each rotation speed [rpm] is read. If it is the air conditioner, its output setting is read.

  In step S15, the ECU 30 calculates the power consumption Pa [W] of the auxiliary machine 28 according to the current operation status of each auxiliary machine 28. In step S16, the ECU 30 calculates the sum of the predicted power consumption Pmot_cons of the motor 14 and the power consumption Pa of the auxiliary device 28 as the predicted power consumption (that is, the system load Psys) of the FC vehicle 10 as a whole.

[2-3. Energy management]
As described above, in the energy management in the present embodiment, operation control of each unit of the FC system 12 is performed. In the following, the description will be focused on the case where the vehicle 10 is in powering.

(2-3-1. Selection of DC / DC converter to be operated)
As part of energy management, the ECU 30 selects which one of the boost converter 24 (FC-VCU 24) and the step-up / down converter 26 (BAT-VCU 26) is to be operated. For example, immediately after the main SW 116 is turned on in a cold region, power is supplied only from the battery 22 in order to warm up the FC 50. In this case, only the BAT-VCU 26 is operated. Further, when the vehicle 10 is accelerated (particularly during rapid acceleration), power is supplied from both the battery 22 and the FC 50. In this case, both the FC-VCU 24 and the BAT-VCU 26 are operated. Furthermore, when the vehicle 10 is cruising, power is supplied only from the FC 50. In this case, only the FC-VCU 24 is operated.

  As a method for selecting a DC / DC converter to be operated, for example, a method disclosed in JP 2009-165244 A (FIG. 14 and the like) may be used.

(2-3-2. Control of inverter input terminal voltage Vinv)
In the present embodiment, when the vehicle 10 is powered, at least one of the FC-VCU 24 and the BAT-VCU 26 is operated with the inverter input terminal voltage Vinv as a control target. That is, a target value of the input terminal voltage Vinv (hereinafter referred to as “target input terminal voltage Vinv_tar”) is set, and the FC-VCU 24 and the BAT-VCU 26 are controlled so that the input terminal voltage Vinv becomes equal to the target input terminal voltage Vinv_tar. To do.

  FIG. 7 is a flowchart for controlling the inverter input terminal voltage Vinv. In step S21, the ECU 30 acquires the motor rotation speed Nmot. The motor rotation speed Nmot here may be either an actual measurement value or a required value. In the present embodiment, the motor rotation speed Nmot (actual measurement value) is acquired from the rotation speed sensor 112.

  In step S22, the ECU 30 acquires the motor torque Tmot. The motor rotation speed Nmot here may be either a measured value (hereinafter referred to as “detected motor torque Tmot_det”) or a required value (hereinafter referred to as “required motor torque Tmot_req”). As the detected motor torque Tmot_det, for example, a detected value of a torque sensor (not shown) can be used. Further, the required motor torque Tmot_req is set according to the opening degree θp of the accelerator pedal 114, for example. Alternatively, the target torque Ttar calculated by the process of FIG. 18 described later may be used as the required motor torque Tmot_req. In FIG. 4, the process in FIG. 18 (S5 in FIG. 4) is performed after the present process (S3 in FIG. 4). In this case, in this process, for example, the target torque Ttar used in the previous calculation cycle can be used.

  In step S23, the ECU 30 uses a plurality of target voltage maps 150a to 150c (hereinafter also referred to as "maps 150a to 150c" and collectively referred to as "target voltage map 150" or "map 150") to be used this time. select. Each map 150 defines the relationship between the combination of the motor rotation speed Nmot and the motor torque Tmot and the target value of the inverter input terminal voltage Vinv (target input terminal voltage Vinv_tar). The contents of the map 150 will be described later.

  In step S24, the ECU 30 calculates the target input terminal voltage Vinv_tar based on the motor rotation speed Nmot in step S21 and the motor torque Tmot in step S22, using the map 150 selected in step S23.

  In step S <b> 25, the ECU 30 acquires the inverter input terminal voltage Vinv (actually measured value) from the voltage sensor 78.

  In step S26, the ECU 30 controls at least one of the boost converter 24 and the step-up / down converter 26 based on the inverter input terminal voltage Vinv and the target input terminal voltage Vinv_tar.

  Specifically, when the input terminal voltage Vinv is smaller than the target input terminal voltage Vinv_tar (Vinv <Vinv_tar), the boosting rate (duty ratio) of the converters 24 and 26 to be operated is increased. When the input terminal voltage Vinv is larger than the target input terminal voltage Vinv_tar (Vinv> Vinv_tar), the boost rate (duty ratio) of the converters 24 and 26 to be operated is decreased. When the input terminal voltage Vinv is equal to the target input terminal voltage Vinv_tar (Vinv = Vinv_tar), the boosting rate (duty ratio) of the converters 24 and 26 to be operated is maintained.

(2-3-3. Selection of Target Voltage Maps 150a to 150c)
FIG. 8 is a flowchart (details of S23 in FIG. 7) for selecting the target voltage maps 150a to 150c. In step S31, the ECU 30 calculates the passing power of the FC-VCU 24 (hereinafter referred to as “passing power Pfccvcu”) and the passing power of the BAT-VCU 26 (hereinafter referred to as “passing power Pbatvcu”).

  Specifically, the ECU 30 multiplies the inverter input terminal voltage Vinv detected by the voltage sensor 78 and the passing current Ifcvcu detected by the current sensor 80 to calculate the passing power Pfcvcu (Pfccvcu = Vinv × Ifcvcu). Further, the ECU 30 multiplies the inverter input terminal voltage Vinv detected by the voltage sensor 78 and the passing current Ibatvcu detected by the current sensor 104 to calculate the passing power Pbatvcu (Pbatvcu = Vinv × Ibatvcu). Alternatively, the passing powers Pfcvcu and Pbatvcu may be calculated by another method described later.

  In step S32, the ECU 30 determines whether or not the passing power Pfcvcu is greater than zero and the passing power Pbatvcu is equal to or less than zero (that is, whether or not power supply is performed only from the FC50). When the passing power Pfcvcu is greater than zero and the passing power Pbatvcu is less than or equal to zero (S32: YES), in step S33, the ECU 30 selects the first map 150a (FIG. 10). The first map 150a is a map used when power is supplied only from the FC 50 and not supplied from the battery 22 (details will be described later).

  If the passing power Pfccvcu is not greater than zero or the passing power Pbatvcu is not less than zero (S32: NO), in step S34, the ECU 30 determines that the passing power Pbatvcu is greater than zero and the passing power Pfcvccu is greater than the passing power Pbatvcu. (That is, whether power is supplied from both the battery 22 and the FC 50 and whether the amount of power supplied from the FC 50 is larger).

  When the passing power Pbatvcu is greater than zero and the passing power Pfcvcu is greater than the passing power Pbatvcu (S34: YES), in step S35, the ECU 30 selects the second map 150b (FIG. 11). The second map 150b is a map used when power is supplied from both the battery 22 and the FC 50 and the FC 50 has a larger power supply amount (details will be described later).

  When the passing power Pbatvcu is not greater than zero or the passing power Pbatvcu is not greater than the passing power Pfcvcu (S34: NO), in step S36, the ECU 30 selects the third map 150c (FIG. 12). The third map 150c is a map used when power is supplied from both the battery 22 and the FC 50 and the FC 50 has a smaller power supply amount (details will be described later).

  Since both the passing powers Pfccvcu and Pbatvcu are calculated using the same inverter input terminal voltage Vinv, the comparison of the passing powers Pfccvcu and Pbatvcu can be considered synonymous with the comparison of the passing currents Ifcvcu and Ibatvcu. Therefore, the passing currents Ifcvcu and Ibatvcu may be acquired as the process of step S31, and the passing currents Ifcvcu and Ibatvcu may be compared as the comparison of the passing powers Pfcvcu and Pbatvcu in steps S32 and S34.

  In addition, in order to determine the magnitude relationship between the passing powers Pfcvcu and Pbatvcu, instead of directly comparing the passing powers Pfcvcu and Pbatvcu, the ratio of the passing powers Pfcvcu and Pbatvcu, that is, Pfcvcu / Pbatvcu or Pbatvcu / Pfcvcu is used. Good.

(2-3-4. Target voltage map 150)
Next, the basic concept of the target voltage map 150 will be described.

(2-3-4-1. Reference map 140 considering the power efficiency of the motor 14)
FIG. 9 shows an example of a reference map 140 that defines the relationship between the combination of the motor rotational speed Nmot and the motor torque Tmot and the required motor voltage Vmot_req. The motor rotation speed Nmot and the motor torque Tmot here may be either measured values or required values. The requested motor voltage Vmot_req is, for example, a target input voltage of the motor 14 that is specified according to the opening θp of the accelerator pedal 114, and takes into account the power efficiency of the motor 14 (hereinafter referred to as “power efficiency Emot”). Is set. The required motor voltage Vmot_req of the present embodiment is set in consideration of the power efficiency of the inverter 16 (hereinafter referred to as “power efficiency Einv”) in addition to the power efficiency Emot of the motor 14. When the requested motor voltage Vmot_req is used as it is as the target input voltage of the motor 14, the requested motor voltage Vmot_req has the same value as the target input terminal voltage Vinv_tar.

  As described above, the reference map 140 in FIG. 9 defines the relationship between the motor rotational speed Nmot and the motor torque Tmot and the required motor voltage Vmot_req in consideration of the power efficiencies Emot and Einv of the motor 14 and the inverter 16. . Hereinafter, the power efficiencies Emot and Einv of the motor 14 and the inverter 16 are integrated and referred to as the power efficiency Eload of the load 40.

  The power efficiency Emot of the motor 14 and the power efficiency Einv of the inverter 16 (that is, the power efficiency Eload of the load 40) vary according to the input voltage to the load 40 (here, the inverter input terminal voltage Vinv). That is, as shown in FIGS. 24A to 24C of Japanese Patent Application Laid-Open No. 2009-165244, in the high efficiency region of the motor 14 or the load 40, the motor rotation speed Nmot increases as the input terminal voltage Vinv increases. The direction or motor torque Tmot tends to increase. In other words, when the motor rotation speed Nmot is high or the motor torque Tmot is high, the power efficiency Emot of the motor 14 and the power efficiency Einv of the inverter 16 tend to increase as the input terminal voltage Vinv increases.

  Therefore, in the reference map 140, when the motor rotation speed Nmot is high or the motor torque Tmot is high, the required motor voltage Vmot_req is increased. Note that in this embodiment, the target voltage map 150 based on the reference map 140 is used, but the reference map 140 itself is not used.

(2-3-4-2. Overview of target voltage maps 150a to 150c considering the power efficiency of the entire FC system 12)
FIG. 10 shows an example of the first map 150a that defines the relationship between the combination of the motor rotation speed Nmot and the motor torque Tmot and the target value of the inverter input terminal voltage Vinv (target input terminal voltage Vinv_tar). FIG. 11 shows an example of the second map 150b that defines the relationship between the combination of the motor rotational speed Nmot and the motor torque Tmot and the target input terminal voltage Vinv_tar. FIG. 12 shows an example of the third map 150c that defines the relationship between the combination of the motor rotational speed Nmot and the motor torque Tmot and the target input terminal voltage Vinv_tar. 10 to 12, the motor rotation speed Nmot and the motor torque Tmot may be either measured values or target values.

  The first map 150a is set based on the reference map 140, and is one of the target voltage maps 150 that are actually used in the present embodiment. The first map 150a is a map used when power is supplied only from the FC 50 and power is not supplied from the battery 22. That is, the first map 150a is used when only the passing power Pfcvcu is present and the passing power Pbatvcu is zero (that is, when only the FC-VCU 24 is performing the boosting operation or the direct coupling operation).

  The second map 150b is set based on the first map 150a, and is one of the maps 150 actually used in the present embodiment. The second map 150b is a map 150 used when power is supplied from both the battery 22 and the FC 50 and the FC 50 has a larger power supply amount (passing current Ifcvcu).

  The third map 150c is set based on the first map 150a, and is one of the maps 150 actually used in the present embodiment. The third map 150c is a map used when power is supplied from both the battery 22 and the FC 50, and the FC 50 has a smaller power supply amount (passing current Ifcvcu).

(2-3-4-3. First map 150a)
(2-3-4-1-1. Overview of the first map 150a)
As shown in FIG. 10, the first map 150a mainly includes four regions (first to fourth regions A1 to A4). Each of the areas A1 to A4 is classified in consideration of the power efficiency of the FC system 12 as a whole (hereinafter referred to as “power efficiency Etotal”). That is, the power efficiency Etotal of the FC system 12 reflects the power efficiency of the boost converter 24 (FC-VCU 24) (hereinafter referred to as “power efficiency Efcvcu”) in addition to the power efficiency Emot and Einv of the motor 14 and the inverter 16. The

  The first area A1 is an area having the same characteristics as the reference map 140. In the second region A2, the voltage is lower than that of the reference map 140 in consideration of the power efficiency Emot, Einv, Efcvcu of the motor 14, the inverter 16 and the boost converter 24 (FC-VCU 24) in the high load state of the motor 14. It is an area. An arrow 152 in FIG. 10 indicates that the voltage of the characteristic of the second region A2 of FIG. 10 is lower than the characteristic of the region corresponding to the second region A2 in the reference map 140, that is, the motor rotation speed Nmot and the motor torque Tmot. Are the same, the target input terminal voltage Vinv_tar in the target voltage map 150 is lower than the required motor voltage Vmot_req in the reference map 140.

  A third region A3 in FIG. 10 is a region where the voltage is lower than that of the reference map 140 in consideration of the power loss Lmot of the motor 14 and the power loss Lfcvcu of the FC-VCU 24 when the motor 14 is in a low load state. An arrow 154 in FIG. 10 indicates that the voltage of the characteristic of the third region A3 of FIG. 10 is lower than the characteristic of the region corresponding to the third region A3 in the reference map 140, that is, the motor rotation speed Nmot and the motor torque Tmot. Are the same, the target input terminal voltage Vinv_tar in the target voltage map 150 is lower than the required motor voltage Vmot_req in the reference map 140.

  The fourth area A4 is an area in which the FC-VCU 24 is in a directly connected state in consideration of the power efficiencies Emot, Einv, and Efcvcu of the motor 14, the inverter 16, and the FC-VCU 24. The fourth region A4 of the present embodiment is variable according to the FC voltage Vfc. An arrow 156 in FIG. 10 indicates that the fourth region A4 in FIG. 10 is variable according to the FC voltage Vfc.

  The first and second regions A1 and A2 correspond to the high load state of the motor 14, and the third and fourth regions A3 and A4 correspond to the low load state of the motor 14. The “high load state” and “low load state” here are defined as follows, for example. That is, when the power efficiency Emot, Einv, Efcvcu of the motor 14, the inverter 16, and the FC-VCU 24 is considered comprehensively (that is, when the power efficiency Etotal of the FC system 12 is considered), when boosting is performed by the FC-VCU 24 The range in which the power efficiency Etotal of the entire FC system 12 is higher when the FC-VCU 24 is in a directly connected state is defined as a “low load state”. On the contrary, the range in which the power efficiency Etotal of the entire FC system 12 is lower when the FC-VCU 24 is directly connected than when boosting by the FC-VCU 24 is defined as a “high load state”.

  Whether the load is high or low (whether the load or output of the motor 14 (hereinafter referred to as “motor output Pmot”) exceeds a predetermined threshold (load threshold or motor output threshold). Judge by no. In other words, the load threshold or the motor output threshold is a threshold for determining a high load state and a low load state. An example of the motor output threshold is a second motor output threshold THpmot2 (S41 in FIG. 14) described later. The load of the motor 14 or the motor output Pmot is defined as the product (Nmot × Tmot) of the motor rotation speed Nmot and the motor torque Tmot. In FIG. 10, a curved line 158 indicates a boundary line between the high load region (first and second regions A1, A2) and the low load region (third and fourth regions A3, A4).

  Note that the comparison of the power efficiency Etotal of the entire FC system 12 between the case where the boosting is performed by the FC-VCU 24 and the case where the FC-VCU 24 is directly connected can be performed based on, for example, a simulation value or a theoretical value.

(2-3-4-3-2. Power loss of boost converter 24 (FC-VCU24))
When power is supplied only from the FC 50, the power efficiency Etotal of the entire FC system 12 is in addition to the power efficiency Emot, Einv or power loss of the motor 14 and the inverter 16 (hereinafter referred to as “power loss Lmot, Linv”). , FC-VCU 24 power efficiency Efcvcu or power loss (hereinafter referred to as “power loss Lfcvcu”) affects. Hereinafter, the power loss Lfcvcu of the FC-VCU 24 will be described.

  FIG. 13 is a diagram showing the relationship between the passing power Pfcvcu of the FC-VCU 24 and the power loss Lfcvcu for each output voltage of the FC-VCU 24 (that is, the inverter input terminal voltage Vinv). In FIG. 13, “Vfc” is the FC voltage Vfc, and M1 to M4 are step-up rates (1 <M1 <M2 <M3 <M4). Note that FIG. 13 assumes that the FC voltage Vfc is constant.

  As shown in FIG. 13, when the passing power Pfcvcu is equal, when the FC-VCU 24 is in the direct connection state, the power loss Lfcvcu of the FC-VCU 24 is small and the output voltage of the FC-VCU 24 (inverter input terminal voltage Vinv) or As the step-up rate increases, the power loss Lfcvcu increases.

  Note that when the FC-VCU 24 is in a directly connected state, the power loss Lfcvcu is extremely small as compared with the case where the FC-VCU 24 is performing a boosting operation. This is because a fixed amount (fixed loss) occurs in the power loss Lfcvcu of the FC-VCU 24 during the boosting operation.

  In the present embodiment, the first to third maps 150a to 150c are set or selected based on the above.

(2-3-4-3-3. Fourth area A4 of the first map 150a)
In the first map 150a of the present embodiment, the first to fourth regions A1 to A4 (FIG. 10) are set in consideration of the power efficiency Etotal of the entire FC system 12. For convenience of explanation, the fourth area A4, the third area A3, the second area A2, and the first area A1 will be described below in this order.

  The fourth region A4 is a region used when the motor 14 is in a low load state and the motor rotation speed Nmot is relatively low. If the motor 14 is in a low load state, the passing power Pfcvcu of the FC-VCU 24 is low. Therefore, in this embodiment, the power efficiency Etotal of the FC system 12 as a whole is more dominant in the power efficiency Efcvcu of the FC-VCU 24 than the power efficiency Emot of the motor 14. Further, even when the motor torque Tmot is relatively high (high torque state), if the FC-VCU 24 is in a directly connected state, the FC 50 can output a relatively large current, and thus can cope with a high torque state. is there.

  Therefore, the FC-VCU 24 is set in a directly connected state with the power efficiency Efcvcu of the FC-VCU 24 as the center. In FIG. 10, the threshold value of the motor rotational speed Nmot (the motor rotational speed threshold value THnmot) is set in order to keep the motor rotational speed Nmot high even when the motor 14 is under a low load. This is because it is necessary to increase Vinv (see the reference map 140 in FIG. 9). That is, when the inverter input terminal voltage Vinv is increased in order to maintain a high motor rotational speed Nmot or not excessively decrease the rotational speed Nmot, the power efficiency Emot of the motor 14 compared to the power efficiency Efcvcu of the FC-VCU 24. Therefore, the FC-VCU 24 is not directly connected.

(2-3-4-3-4. Third area A3 of the first map 150a)
The third region A3 is a region used when the motor output Pmot is in a relatively low state (low load state) and the motor rotational speed Nmot is relatively high. As described in relation to the fourth region A4, in order to maintain the high motor rotation speed Nmot or not excessively reduce the rotation speed Nmot even when the motor 14 is lightly loaded, the inverter input terminal voltage Vinv Need to be increased (see reference map 140 in FIG. 9). When the input terminal voltage Vinv is increased in order to maintain a high motor rotational speed Nmot or not to excessively decrease the rotational speed Nmot, the power efficiency Emot of the motor 14 can be ignored as compared with the power efficiency Efcvcu of the FC-VCU 24. Disappear. Further, in the low load state and the high rotation state, the motor torque Tmot is low. Therefore, boosting by the FC-VCU 24 is performed without setting the FC-VCU 24 in a directly connected state.

  However, in the third region A3, the inverter input terminal voltage Vinv is made lower than the characteristic in the reference map 140. This is because the power efficiency Efcvcu of the FC-VCU 24 is taken into consideration in addition to the power efficiency Emot and Einv of the motor 14 and the inverter 16.

(2-3-4-3-5. Second area A2 of first map 150a)
The second region A2 is a region used when the motor output Pmot is relatively high (high load state) and the motor torque Tmot is relatively low (low torque state). As described above, when the motor 14 is in a high load state, the passing power Pfcvcu of the FC-VCU 24 increases, and the influence of the power efficiency Efcvcu of the FC-VCU 24 on the power efficiency Etotal of the FC system 12 increases.

  Therefore, the boosting rate of the FC-VCU 24 is set lower than that of the reference map 140 in consideration of the power efficiency Emot, Einv of the motor 14 and the inverter 16 and the power efficiency Efccv of the FC-VCU 24. As a result, the power efficiency Etotal of the FC system 12 as a whole can be improved.

(2-3-4-3-6. First area A1 of first map 150a)
The first region A1 is a region used when the motor output Pmot is relatively high (high load state) and the motor torque Tmot is relatively high (high torque state). In the first area A1, the characteristics of the reference map 140 are used as they are. This is because the power efficiency Emot and Einv of the motor 14 and the inverter 16 become dominant in the power efficiency Etotal of the FC system 12 in a high load and high torque state.

  In FIG. 10, the boundary line 160 between the first area A1 and the second area A2 is inclined upward. This is a result of reflecting the power efficiency Etotal of the FC system 12.

(2-3-4-3-7. Specific setting method of each area A1 to A4 in the first map 150a)
FIG. 14 is a flowchart showing a method of setting each area (first to fourth areas A1 to A4) in the first map 150a. In the present embodiment, it should be noted that FIG. 14 is not a process executed by the ECU 30, but a reference or index when setting the map 150a used by the ECU 30. However, the contents shown in FIG. 14 may be used as the processing executed by the ECU 30.

  In step S41, it is determined whether or not the motor 14 is in a low load state. Specifically, the output of the motor 14 (motor output Pmot) exceeds the first threshold (hereinafter referred to as “first motor output threshold THpmot1” or “threshold THpmot1”) and is equal to the second threshold (hereinafter referred to as “second motor output threshold”). It is determined whether it is less than “THpmot2” or “threshold THpmot2”. The threshold value THpmot1 is a value (lower limit value) for determining whether or not the motor 14 is in the driving state instead of the regenerative state, and is, for example, 0 kW or a nearby value. The threshold value THpmot2 is an upper limit value for determining whether the motor 14 is in a low load state.

  The map 150a may be changed according to the FC voltage Vfc. Specifically, the map 150a can be changed by switching the threshold value THpmot2 according to the FC voltage Vfc.

  FIG. 15 is a diagram illustrating an example of the relationship between the FC voltage Vfc and the second motor output threshold THpmot2. As shown in FIG. 15, when the FC voltage Vfc is equal to or less than a threshold value (hereinafter referred to as “FC voltage threshold value THvfc”), the second motor output threshold value THpmot2 is made constant. On the other hand, when the FC voltage Vfc exceeds the FC voltage threshold THvfc, the second motor output threshold THpmot2 is gradually increased. Thus, when the FC voltage Vfc is relatively high, the second motor output threshold THpmot2 gradually increases. Therefore, as the FC voltage Vfc increases, the fourth area A4 becomes wider (see FIG. 14). As a result, when the FC voltage Vfc is high, the direct connection process is easily performed.

  As described above, the arrow 156 in FIG. 10 shows how the respective regions A1 to A4 (particularly the fourth region A4) change as a result of switching the second motor output threshold THpmot2 in accordance with the FC voltage Vfc. Yes.

  If the motor 14 is not in a low load state in step S41 in FIG. 14 (S41: NO), it is determined in step S42 whether the motor torque Tmot is high. Specifically, the determination is made based on whether or not the motor torque Tmot exceeds the torque threshold THtmot.

  When the motor torque Tmot is high (S42: YES), in step S43, the required motor voltage Vmot_req is set to the target input terminal voltage Vinv_tar as it is (Vinv_tar ← Vmot_req). The value is the value of the first area A1 of the first map 150a.

  When the motor torque Tmot is not high (S42: NO), in step S44, a value obtained by subtracting a predetermined positive value α from the required motor voltage Vmot_req is set as the target input terminal voltage Vinv_tar (Vinv_tar ← Vmot_req−α). This value is the value of the second area A2 of the first map 150a. The predetermined value α is a value in consideration of the power efficiency Efcvcu of the FC-VCU 24 in addition to the power efficiency Emot and Einv of the motor 14 and the inverter 16 (that is, a value in consideration of the power efficiency Etotal of the FC system 12).

  Returning to step S41, when the motor 14 is in a low load state (S41: YES), in step S45, it is determined whether or not the motor rotation speed Nmot is high (whether or not it is in a high rotation state). Specifically, it is determined whether or not the motor rotation speed Nmot exceeds a predetermined threshold (rotation speed threshold THnmot) (see FIG. 10). The rotational speed threshold value THnmot is a threshold value for determining whether or not the motor rotational speed Nmot is high. The inverter input terminal voltage Vinv and the motor torque for maintaining the high rotational state or preventing the rotational speed Nmot from being excessively decreased. It is set in consideration of Tmot.

  When the motor rotation speed Nmot is high (S45: YES), in step S46, a value obtained by subtracting a predetermined positive value β from the requested motor voltage Vmot_req is set as the target input terminal voltage Vinv_tar (Vinv_tar ← Vmot_req−β). This value is the value of the third area A3 of the first map 150a. The predetermined value β is a value considering the power loss Lmot of the motor 14 and the power loss Lfcvcu of the boost converter 24. For example, the sum of the power losses Lmot and Lfcvcu is set to a value that is the minimum value or a value in the vicinity thereof. Alternatively, the predetermined value β may be a value that considers the power loss Linv of the inverter 16 in addition to the power losses Lmot and Lfcvcu of the motor 14 and the boost converter 24. For example, the sum of the power losses Lmot, Linv, and Lfcvcu is set to a value that is a minimum value or a value near the minimum value.

  If the motor rotation speed Nmot is not high (S45: NO), in step S47, the FC voltage Vfc is set to the target input terminal voltage Vinv_tar (Vinv_tar ← Vfc). This value is the value of the fourth area A4 of the first map 150a. Setting the FC voltage Vfc to the target input terminal voltage Vinv_tar means that the boost converter 24 is not boosted, that is, a direct connection process. Here, the target value may be used instead of the FC voltage Vfc as the actual measurement value.

  As described above, in FIG. 14, whether the motor 14 is in a low load state (S41), whether the motor 14 is in a high torque state (S42), and whether the motor 14 is in a high rotation state. The first to fourth regions A1 to A4 are divided based on (S45).

  Alternatively, the first to fourth regions A1 to A4 may be divided by changing the order in which the above three criteria are determined. Alternatively, the number of regions may not be four, but may be divided into two, three, or five or more regions.

(2-3-4-4. Second map 150b)
(2-3-4-1-1. Overview of second map 150b)
As shown in FIG. 11, like the first map 150a, the second map 150b mainly includes four regions (first to fourth regions A1 to A4). However, in consideration of the presence of the passing power Pbatvcu of the BAT-VCU 26 in addition to the passing power Pfcvcu of the FC-VCU 24, that is, in addition to the power supply from the FC 50, there is also the power supply from the battery 22, The characteristics or ranges of the fourth areas A2 to A4 are changed as compared with the first map 150a. More specifically, the characteristics or ranges of the second to fourth areas A2 to A4 are changed in comparison with the first map 150a based on the difference in power efficiency characteristics of the FC-VCU 24 and the BAT-VCU 26.

(2-3-4-2-2. Power efficiency of FC-VCU24 and BAT-VCU26)
FIG. 16 is a diagram for explaining the power efficiencies Efcvcu and Ebatvcu of the FC-VCU 24 and the BAT-VCU 26. The horizontal axis of FIG. 16 indicates the passing powers Pfcvcu and Pbatvcu of the FC-VCU 24 and the BAT-VCU 26. The vertical axis in FIG. 16 indicates the power efficiencies Efcvcu and Ebatvcu of the FC-VCU 24 and the BAT-VCU 26, respectively.

  In FIG. 16, an example of characteristics when the FC-VCU 24 is performing a boosting operation, an example of characteristics when the FC-VCU 24 is not performing a boosting operation (that is, in a directly connected state), and a BAT-VCU 26 An example of the characteristic when the BAT-VCU 26 is not performing the boosting operation and an example of the characteristic when the BAT-VCU 26 is not performing the boosting operation are shown. In FIG. 16, it is assumed that the FC voltage Vfc is constant.

  As can be seen from FIG. 16, for any of the characteristics, the power efficiency Efcvcu and Ebatvcu increase as the passing powers Pfcvccu and Pbatvcu increase. However, when the boosting operation is performed for both the FC-VCU 24 and the BAT-VCU 26, when the passing powers Pfccvcu and Pbatvcu are below a specific value (passing power threshold THp in FIG. 16), the slope is large. When the passing powers Pfccvcu and Pbatvcu exceed a specific value (threshold value THp), the inclination becomes small. This is because a fixed amount (fixed loss) occurs in the power losses Lfcvcu and Lbatvcu of the FC-VCU 24 and the BAT-VCU 26 during the boosting operation. Note that the threshold THp in FIG. 16 is common to the FC-VCU 24 and the BAT-VCU 26, but may be different between the FC-VCU 24 and the BAT-VCU 26.

  Further, in both the FC-VCU 24 and the BAT-VCU 26, the power efficiencies Efcvcu and Ebatvcu are higher in the direct connection than in the boosting. This is because the fixed loss occurs during boosting.

  Further, when the passing powers Pfccvcu and Pbatvcu have the same value, the power efficiency Efcvcu of the FC-VCU 24 is higher than the power efficiency Ebatvcu of the BAT-VCU 26 both when boosting and when directly connected. This is because the FC-VCU 24 is a boost converter and the circuit configuration is relatively simple (see FIG. 2), and the power consumption during operation is relatively small, whereas the BAT-VCU 26 is a buck-boost converter. This is because the circuit configuration is relatively complicated (see FIG. 3) and the power consumption during operation is relatively large.

  In the present embodiment, the second and third maps 150b and 150c are set or selected based on the above.

(2-3-4-4-3. Second and third regions A2 to A3 of the second map 150b)
When the motor rotation speed Nmot and the motor torque Tmot are constant, the second and third regions A2 of the second map 150b are compared with the second and third regions A2 and A3 (FIG. 10) of the first map 150a. A3 (FIG. 11) is set to a characteristic that lowers the target input terminal voltage Vinv_tar. The arrows 172 and 174 in FIG. 11 indicate this.

  By making such a setting, it becomes possible to improve the power efficiency Etotal of the FC system 12 as a whole. That is, as described above, if the passing powers Pfcvcu and Pbatvcu are equal, the power efficiency Efcvcu of the FC-VCU 24 is higher than the power efficiency Ebatvcu of the BAT-VCU 26 at both the boosting time and the direct connection time.

  For this reason, if the motor output Pmot (= rotation speed Nmot × motor torque Tmot) is equal, both the FC-VCU 24 and the BAT-VCU 26 are operating, compared to the case where only the FC-VCU 24 is operating. As a result, the power efficiency Etotal of the entire FC system 12 decreases or the power loss Ltotal of the entire FC system 12 increases. Therefore, in the second and third regions A2 and A3 of the second map 150b, the passing powers Pfcvcu and Pbatvcu are suppressed by lowering the target input terminal voltage Vinv_tar than in the case of the first map 150a. Thus, by reducing the power losses Lfcvcu and Lbatvcu in the FC-VCU 24 and the BAT-VCU 26, respectively, the power loss Ltotal of the entire FC system 12 can be reduced or the power efficiency Etotal can be improved.

  As described above, the second region A2 corresponds to a high load state of the motor 14. For this reason, the reduction of the power loss Ltotal can be increased by reducing the passing powers Pfcvcu and Pbatvcu as described above.

  Further, the third region A3 corresponds to a state where the motor rotation speed Nmot is high and the motor torque Tmot is low (for example, downhill) even when the motor 14 is in a low load state. For this reason, even when the passing electric powers Pfcvcu and Pbatvcu are reduced, the influence on the running performance of the vehicle 10 can be suppressed to a relatively small level.

(2-3-4-4-4. Fourth area A4 of the second map 150b)
When the motor rotation speed Nmot and the motor torque Tmot are constant, the fourth area A4 of the second map 150b has an upper limit value (the rotation speed threshold) compared to the fourth area A4 of the first map 150a. THnmot) is set low. The arrow 176 in FIG. 11 indicates this. As a result, the fourth area A4 becomes narrower and the third area A3 becomes wider.

  In the present embodiment, the power efficiency Etotal of the FC system 12 as a whole can be improved by making such settings. That is, as described above, the fourth area A4 corresponds to a low load state other than the third area A3. When the load is low, that is, when the passing power Pbatvcu is relatively low, the power efficiency Ebatvcu decreases (increases the power loss Lbatvcu) (see FIG. 16).

  Therefore, in the fourth region A4 of the second map 150b, the threshold value THnmot is relatively increased to facilitate the boosting operation and to easily increase the passing power Pbatvcu. Thereby, the power efficiency Ebatvcu is improved or the power loss Lbatvcu is reduced. Accordingly, although the power efficiency Ebatvcu of the FC-VCU 24 is reduced or the power loss Lbatvcu is increased, it is possible to improve the power efficiency Etotal of the FC system 12 as a whole or reduce the power loss Ltotal.

  Note that, similarly to the fourth area A4 of the first map 150a, the fourth area A4 of the second map 150b may be changed according to the FC voltage Vfc.

(2-3-4-5. Third map 150c)
Similar to the first map 150a and the second map 150b, the third map 150c has mainly four regions (first to fourth regions A1 to A4). However, considering that the degree of power supply from the battery 22 is larger than in the case of the second map 150b, the characteristics or ranges of the second to fourth regions A2 to A4 are compared with the second map 150b. And change it further.

  As described above, in the second map 150b, the range of the second to fourth areas A2 to A4 is defined based on the difference in power efficiency characteristics between the FC-VCU 24 and the BAT-VCU 26 (FIG. 16). It is changed as compared with the one map 150a.

  The third map 150c is selected when the degree of power supply from the battery 22 side is greater than in the case of the second map 150b (see S34 to S36 in FIG. 8). In other words, the influence of the power efficiency Ebatvcu of the BAT-VCU 26 on the power efficiency Etotal of the entire FC system 12 is greater than in the case of the second map 150b.

  Therefore, in the third map 150c, the characteristics or ranges of the second to fourth areas A2 to A4 are further changed compared to the second map 150b. This is indicated by the fact that the arrows 182, 184 and 186 in the third map 150 c are longer than the arrows 172, 174 and 176 in the second map 150 b, respectively.

  More specifically, in the second and third regions A2 and A3 of the third map 150c, the passing powers Pfcvcu and Pbatvcu are suppressed by lowering the target input terminal voltage Vinv_tar than in the case of the second map 150b. Accordingly, the power loss Lfvccu and Lbatvcu in the FC-VCU 24 and the BAT-VCU 26 are reduced, thereby reducing the power loss Ltotal of the entire FC system 12 or improving the power efficiency Etotal.

  In addition, as compared with the fourth area A4 of the second map 150b, the fourth area A4 of the third map 150c further lowers the rotation speed threshold THnmot. The arrow 186 in FIG. 12 indicates this. As a result, the fourth region A4 is further narrowed, and the third region A3 is further widened.

  Note that, similarly to the fourth region A4 of the first map 150a and the second map 150b, the fourth region A4 of the third map 150c may be changed according to the FC voltage Vfc.

(2-3-5. Examples of various controls)
FIG. 17 shows an example of a time chart when various controls according to the present embodiment are used. The vehicle 10 is in a cruising state at a relatively low vehicle speed between time points t1 and t2 in FIG. It is. Here, the FC-VCU 24 is in a directly connected state (target input terminal voltage Vinv_tar = FC voltage Vfc), and the target input terminal voltage Vinv_tar specified from the motor rotation speed Nmot and the motor torque Tmot belongs to the fourth region A4 (FIG. 14). S47). For this reason, the passing power Pfcvcu is a positive value, and the passing power Pbatvcu is zero. In other words, the ECU 30 operates only the FC-VCU 24 and does not operate the BAT-VCU 26.

  At time t2, the accelerator pedal 114 is depressed, and the motor output Pmot increases. The reason why the passing electric power Pbatvcu remains zero between the time points t2 and t3 is that the combination of the motor rotational speed Nmot and the motor torque Tmot belongs to the fourth region A4.

  When the time point t3 is reached, the ECU 30 starts the operation of the FC-VCU 24 and the BAT- from the operation of the FC-VCU 24 only when a predetermined condition (for example, the opening degree θp of the accelerator pedal 114 is equal to or greater than the threshold value) is satisfied. The operation is switched to the operation of the VCU 26. Along with this, the passing powers Pfcvcu and Pbatvcu become positive values (S32: NO in FIG. 8), and the target voltage map 150 is switched from the first map 150a to the second map 150b. As a result, the ECU 30 sets the target input terminal voltage Vinv_tar based on the motor rotation speed Nmot and the motor torque Tmot using the second map 150b.

  That is, in FIG. 17, the target input terminal voltage Vinv_tar indicated by a solid line is a value by the control of the present embodiment, and the target input terminal voltage Vinv_tar indicated by a broken line is controlled according to the comparative example (first map 150a in FIG. 10). (Control using only as it is). In FIG. 17, the target input terminal voltage Vinv_tar (solid line) of the present embodiment becomes larger than that of the comparative example at the time point t3. This is because the characteristics of the third region A3 in the second map 150b (FIG. 11) are used.

[2-4. FC power generation control]
The FC power generation control (S4) in FIG. 4 will be described. As described above, the ECU 30 controls peripheral devices of the FC stack 50 as the FC power generation control. Specifically, ECU30 controls these apparatuses using the command value of these apparatuses calculated by energy management (S3 of FIG. 4).

[2-5. Torque control of motor 14]
The motor torque control (S5) in FIG. 4 will be described with reference to FIG. FIG. 18 shows a flowchart of motor torque control (details of S5 in FIG. 4). In step S51, the ECU 30 reads the motor rotational speed Nmot from the rotational speed sensor 112. In step S52, the ECU 30 reads the opening degree θp of the accelerator pedal 114 from the opening degree sensor 110.

  In step S53, the ECU 30 calculates the temporary target torque Ttar_p [N · m] of the motor 14 based on the motor rotation speed Nmot and the opening degree θp. Specifically, a map that associates the rotational speed Nmot, the opening degree θp, and the temporary target torque Ttar_p is stored in a storage unit (not shown), and the temporary target torque Ttar_p is based on the map, the rotational speed Nmot, and the opening degree θp. Is calculated.

  In step S54, the ECU 30 calculates a limit output (motor limit output Pm_lim) [W] of the motor 14 equal to a limit value (limit supply power Ps_lim) [W] of power that can be supplied from the FC system 12 to the motor 14. Specifically, the limit supply power Ps_lim and the motor limit output Pm_lim are calculated from the sum of the FC power Pfc from the FC stack 50 and the limit value of power that can be supplied from the battery 22 (limit output Pbat_lim) [W]. (Pm_lim = Ps_lim ← Pfc + Pbat_lim−Pa).

  In step S55, the ECU 30 calculates a torque limit value Tlim [N · m] of the motor 14. More specifically, the torque limit value Tlim is obtained by dividing the motor limit output Pm_lim by the vehicle speed V (Tlim ← Pm_lim / V).

  On the other hand, if it is determined in step S54 that the motor 14 is regenerating, the ECU 30 calculates the limit supply regenerative power Ps_reglim. The limit supply regenerative power Ps_reglim is obtained by subtracting the power consumption Pa of the auxiliary machine 28 from the sum of the limit value of power that can be charged to the battery 22 (limit charge Pbat_chglim) and the FC power Pfc from the FC stack 50 (Ps_reglim). = Pbat_chglim + Pfc-Pa). When the regeneration is being performed, in step S55, the ECU 30 calculates a regeneration torque limit value Treglim [N · m] of the motor 14. Specifically, a value obtained by dividing the limit supply regenerative power Ps_reglim by the vehicle speed Vs is set as a torque limit value Tlim (Tlim ← Ps_reglim / Vs).

  In step S56, the ECU 30 calculates a target torque Ttar [N · m]. Specifically, the ECU 30 sets the target torque Ttar to the temporary target torque Ttar_p that is limited by the torque limit value Tlim. For example, when the temporary target torque Ttar_p is equal to or less than the torque limit value Tlim (Ttar_p ≦ Tlim), the temporary target torque Ttar_p is directly used as the target torque Ttar (Ttar ← Ttar_p). On the other hand, when the temporary target torque Ttar_p exceeds the torque limit value Tlim (Ttar_p> Tlim), the torque limit value Tlim is set as the target torque Ttar (Ttar ← Tlim).

  Then, the motor 14 is controlled using the calculated target torque Ttar.

3. As described above, according to the present embodiment, the required motor voltage Vmot_req specified based on the motor rotational speed Nmot and the motor torque Tmot in consideration of the power efficiency Emot of the motor 14 is expressed as FC−. The target input terminal voltage Vinv_tar (that is, the target input voltage to the motor 14) is weighted according to the comparison result of the passing powers Pfccvcu and Pbatvcu of the VCU 24 (first DC / DC converter) and the BAT-VCU 26 (second DC / DC converter). ). As a result, it is possible to calculate the target input terminal voltage Vinv_tar reflecting the influence of the passing powers Pfccvcu and Pbatvcu. Therefore, it is possible to improve the power efficiency Etotal (energy efficiency) of the FC system 12 (power system) as a whole.

  In the present embodiment, the ECU 30 (control device) compares the passing powers Pfccvcu and Pbatvcu of the FC-VCU 24 (first DC / DC converter) and the BAT-VCU 26 (second DC / DC converter) with the passing currents Ifcvcu and Ibatvcu (outlet end). Current). In this case, the passing powers Pfcvcu and Pbatvcu of the FC-VCU 24 and the BAT-VCU 26 can be easily compared.

  In the present embodiment, the ECU 30 (control device) sets target voltage maps 150a to 150c (target input terminal voltage maps) that define the relationship between the motor rotational speed Nmot and the motor torque Tmot and the target input terminal voltage Vinv_tar, The maps 150a to 150c are switched in accordance with the comparison results of the passing powers Pfcvcu and Pbatvcu (FIG. 8). As a result, the target input terminal voltage Vinv_tar can be directly calculated from the rotation speed Nmot and the torque Tmot, so that calculation of the required motor voltage Vmot_req can be omitted when the motor 14 is driven. Accordingly, it is possible to improve the calculation speed or reduce the calculation load.

  In the present embodiment, the ECU 30 (control device) can perform direct connection processing for supplying power from the FC 50 to the inverter 16 without boosting the FC-VCU 24 (first DC / DC converter) (FIGS. 10 to 12). 4th area | region A4). When the motor rotational speed Nmot and the motor torque Tmot are constant, the BAT-VCU 26 (second DC / DC converter) has a smaller PASS-power than the BAT-VCU 26 (second DC / DC converter) (FIG. 12). When the passing power is larger in the FC-VCU 24 than in the VCU 26 (FIG. 11), the timing of performing the direct connection processing is earlier. Thereby, energy efficiency can be improved in connection with the direct connection process.

  According to this embodiment, the FC vehicle 10 has the FC system 12, and the motor 14 is a traveling motor. Thereby, it becomes possible to provide the FC vehicle 10 excellent in power efficiency.

4). Modifications It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the description in this specification. For example, the following configuration can be adopted.

[4-1. Installation target]
In the above embodiment, the FC system 12 is mounted on the FC vehicle 10. However, the present invention is not limited to this. For example, from the viewpoint of using the FC-VCU 24 (DC / DC converter) that boosts the FC voltage Vfc and supplies it to the motor 14. If so, the FC system 12 may be mounted on another target. For example, the FC system 12 can be used for a moving body such as a ship or an aircraft. Alternatively, the FC system 12 may be applied to a robot, a manufacturing apparatus, a household power system, or a home appliance.

[4-2. Configuration of FC system 12]
In the above embodiment, the FC 50 and the high voltage battery 22 are arranged in parallel, the boost converter 24 is arranged in front of the FC 50, and the step-up / down converter 26 is arranged in front of the battery 22. However, the present invention is not limited to this. For example, the DC / DC converter disposed in front of the battery 22 may be a boost type instead of a buck-boost type.

  In the above embodiment, the motor 14 is an AC type, but for example, from the viewpoint of using the FC-VCU 24 (DC / DC converter) that boosts the FC voltage Vfc and supplies it to the motor 14, the motor 14 is a direct current. It can also be an expression. In this case, the inverter 16 can be omitted.

  In the above embodiment, the motor 14 is used for driving or driving the FC vehicle 10, but for example, from the viewpoint of using the FC-VCU 24 (DC / DC converter) that boosts the FC voltage Vfc and supplies it to the motor 14. For example, it is not limited to this. For example, the motor 14 may be used for on-vehicle equipment (for example, electric power steering, air compressor, air conditioner).

  In the above embodiment, the circuit of FIG. 2 is shown as a configuration example of the FC-VCU 24, and the circuit of FIG. 3 is shown as a configuration example of the BAT-VCU 26. However, from the viewpoint of the function as a DC / DC converter, the configurations of the FC-VCU 24 and the BAT-VCU 26 are not limited thereto. For example, instead of the circuit of FIG. 2, it is possible to use a boost converter (and control for it) having the configuration shown in FIG. 2 of Japanese Patent Laid-Open No. 2009-165244.

[4-3. Control of FC system 12]
(4-3-1. Comparison of passing powers Pfcvcu and Pbatvcu)
In the present embodiment, the ECU 30 (control device) compares the passing powers Pfccvcu and Pbatvcu of the FC-VCU 24 (first DC / DC converter) and the BAT-VCU 26 (second DC / DC converter) with the passing currents Ifcvcu and Ibatvcu (outlet end). Current). However, focusing on other characteristics, the comparison can be performed using the FC current Ifc and the battery current Ibat (inlet end current).

(4-3-2. Target voltage maps 150a to 150c)
(4-3-2-1. First to fourth regions A1 to A4)
In the above-described embodiment, the target voltage map 150 is mainly divided into four areas. However, if attention is paid to other characteristics (for example, the point where the fourth area A4 is changed according to the FC voltage Vfc), the present invention is not limited to this. . For example, any two or three of the first to fourth regions A1 to A4 may be used. For example, a combination of only the first, second, and fourth regions A1, A2, and A4, a combination of only the first, third, and fourth regions A1, A3, and A4, and a combination of only the first and fourth regions A1, and A4 Alternatively, a combination of only the second and fourth areas A2 and A4 is also possible. Alternatively, other regions can be set in addition to the first to fourth regions A1 to A4.

  In the above embodiment, the fourth region A4 of the target voltage map 150 can be changed according to the FC voltage Vfc (see the arrow 156 in FIG. 10 and the characteristics in FIG. 15). However, if attention is paid to other characteristics (for example, points divided into the first to fourth areas A1 to A4), the fourth area A4 may be fixed.

(4-3-2-2. Selection of map 150)
In the above embodiment, three target voltage maps 150 (first to third maps 150a to 150c) are used. However, if other features are noted, the number of maps 150 may be two or four or more. . For example, only a combination of the first map 150a and the second map 150b or only a combination of the first map 150a and the third map 150c may be used.

  In the above embodiment, the map 150 is selected using the passing powers Pfcvcu and Pbatvcu (FIG. 8). However, if attention is paid to other characteristics (for example, a point where a plurality of maps 150 are used), the map 150 is selected by other methods. It is also possible to select.

  FIG. 19 is a flowchart (details of S23 of FIG. 7) for selecting the target voltage maps 150a to 150e as a modification of FIG. In the modification of FIG. 19, the number of maps 150 is five, and when selecting the map 150, the power efficiencies Efcvcu and Ebatvcu of the FC-VCU 24 and the BAT-VCU 26 are used in addition to the passing powers Pfcvcu and Pbatvcu.

  Steps S61 to S63 in FIG. 19 are the same as S31 to S33 in FIG.

  When the passing power Pfccvcu is not greater than zero or the passing power Pbatvcu is not less than or equal to zero (S62: NO), in step S64, the ECU 30 calculates power efficiencies Efcvcu and Ebatvcu. In the calculation, for example, characteristics as shown in FIG. 16 are stored in advance as a map, and the power efficiencies Efccvcu and Ebatvcu are specified according to the passing powers Pfcvcu and Pbatvcu.

  In step S65, the ECU 30 calculates a difference between power efficiency Efcvcu and Ebatvcu (hereinafter referred to as “difference ΔE”) (ΔE = Efcvcu−Ebatvcu).

  In step S66, the ECU 30 determines whether or not the power efficiencies Efcvcu and Ebatvcu are relatively close to each other. Specifically, it is determined whether or not the difference ΔE is equal to or greater than a first efficiency difference threshold THΔE1 (hereinafter referred to as “threshold THΔE1”) and equal to or less than a second efficiency difference threshold THΔE2 (hereinafter referred to as “threshold THΔE2”). To do. When the difference ΔE is greater than or equal to the threshold value THΔE1 and less than or equal to the threshold value THΔE2 (S66: YES), in step S63, the ECU 30 selects the first map 150a (FIG. 10). That is, since the power efficiencies Efcvcu and Ebatvcu are relatively close to each other, the power efficiency Etotal of the FC system 12 is improved by using the first map 150a when only the FC 50 supplies power.

  In step S66, when the difference ΔE is less than the threshold value THΔE1 or exceeds the threshold value THΔE2 (S66: NO), in step S67, the ECU 30 determines whether or not the difference ΔE exceeds the threshold value THΔE2, that is, FC is greater than BAT-VCU26. -Determine whether the VCU 24 is more power efficient. When the difference ΔE exceeds the threshold value THΔE2 (S67: YES), the process proceeds to step S68.

  Steps S68 to S70 are the same as steps S34 to S36 of FIG. That is, the ECU 30 selects the second map 150b (FIG. 11) or the third map 150c (FIG. 12) according to the passing electric powers Pfcvcu and Pbatvcu.

  When the difference ΔE does not exceed the threshold THΔE2 (S67: No), the difference ΔE is less than the threshold THΔE1, that is, the FC-VCU 24 has lower power efficiency than the BAT-VCU 26. In this case, in steps S71 to S73, the ECU 30 selects the fourth map 150d (FIG. 20) or the fifth map 150e (FIG. 21).

  That is, in step S71, the ECU 30 determines whether or not the passing power Pbatvcu is greater than zero and the passing power Pfctvcu is greater than the passing power Pbatvcu (that is, power is supplied from both the battery 22 and the FC50 and It is determined whether or not the power supply amount from the FC 50 is larger.

  When the passing power Pbatvcu is greater than zero and the passing power Pfcvcu is greater than the passing power Pbatvcu (S71: YES), in step S72, the ECU 30 selects the fourth map 150d (FIG. 20).

  FIG. 20 shows an example of a fourth map 150d that defines the relationship between the combination of the motor rotational speed Nmot and the motor torque Tmot and the target input terminal voltage Vinv_tar. The fourth map 150d is a map used when power is supplied from both the battery 22 and the FC 50, the FC-VCU 24 has lower power efficiency than the BAT-VCU 26, and the FC 50 has a larger power supply amount. It is.

  When the motor rotation speed Nmot and the motor torque Tmot are constant, the fourth area A4 of the fourth map 150d has an upper limit value (the rotation speed threshold) compared to the fourth area A4 of the first map 150a. THnmot) is set low. Thereby, it becomes easy to enter the boosted state, and it becomes easy to increase the passing power Pfcvcu in the low load state. As a result, it is possible to improve the power efficiency Efcvcu and Ebatvcu (see FIG. 16). An arrow 180 in FIG. 20 indicates that the threshold value THnmot is set low. When the threshold value THnmott is set low, the fourth area A4 becomes narrow and the third area A3 becomes wide.

  In step S71 of FIG. 19, when the passing power Pbatvcu is not greater than zero or the passing power Pfcvcu is not greater than the passing power Pbatvcu (S71: NO), in step S73, the ECU 30 causes the fifth map 150e (FIG. 21). ) Is selected.

  FIG. 21 shows an example of a fifth map 150e that defines the relationship between the combination of the motor rotational speed Nmot and the motor torque Tmot and the target input terminal voltage Vinv_tar. The fifth map 150e is a map used when power is supplied from both the battery 22 and the FC 50, the FC-VCU 24 is lower in power efficiency than the BAT-VCU 26, and the FC 50 has a lower power supply amount. It is.

  In such a case, the power efficiency Efcvcu of the FC-VCU 24 can hardly contribute to the power efficiency Etotal of the entire FC system 12. Therefore, the fifth map 150e has the same characteristics as the reference map 140 described in the above embodiment. That is, the fifth map 150e has characteristics that take into consideration the power efficiency Emot and Einv of the motor 14 and the inverter 16 without considering the power efficiency Efcvcu of the FC-VCU 24. Note that the power efficiency Ebatvcu of the BAT-VCU 26 may be reflected in the fifth map 150e.

  According to the modified example of FIG. 19, the power efficiency Efcvcu and Ebatvcu of the FC-VCU 24 and the BAT-VCU 26 can be largely reflected in the power efficiency Etotal of the FC system 12.

(4-3-2-3. Method other than selection of map 150)
In the above embodiment, the maps 150a to 150c are selected using the passing powers Pfcvcu and Pbatvcu of the FC-VCU 24 and the BAT-VCU 26 (FIG. 8). However, if other features (for example, the point at which the target input terminal voltage Vinv_tar is changed in accordance with the passing powers Pfcvcu and Pbatvcu) are noted, the map 150 may not be selected.

  FIG. 22 is a flowchart for controlling the inverter input terminal voltage Vinv as a modification of FIG. In the processing of FIG. 22, the target voltage map 150 uses only the first map 150a. As described above, the first map 150a is a map used when power is supplied only from the FC 50. When power is supplied from the FC 50 and the battery 22, the target input terminal voltage Vinv_tar (referred to as “temporary target input terminal voltage Vinv_tar_temp” for convenience) specified using the first map 150 a is corrected. The target input terminal voltage Vinv_tar is calculated.

  Steps S81 and S82 in FIG. 22 are the same as steps S21 and S22 in FIG.

  In step S83, the ECU 30 uses the first map 150a to calculate the temporary target input terminal voltage Vinv_tar_temp based on the motor rotation speed Nmot in step S81 and the motor torque Tmot in step S82. In the modification of FIG. 22, only the first map 150 a (temporary required input voltage map) is used as the map 150. For this reason, the map 150 is not selected.

  In the first map 150a of the modified example of FIG. 22, the target input terminal voltage Vinv_tar in FIG. 10 may be replaced with the temporary target input terminal voltage Vinv_tar_temp.

  In step S84, the ECU 30 calculates the passing power Pfcvcu of the FC-VCU 24 and the passing power Pbatvcu of the BAT-VCU 26. This process is the same as step S31 in FIG.

  In step S85, the ECU 30 sets the correction coefficient k based on the passing electric powers Pfcvccu and Pbatvcu calculated in step S84. The correction coefficient k is a coefficient for reflecting the influence of the passing power Pbatvcu from the BAT-VCU 26.

  That is, as described above, only the first map 150a is used as the map 150 in the modification of FIG. The first map 150 a is a map used when power is supplied only from the FC 50 and power is not supplied from the battery 22. In the above embodiment (FIG. 8), the first to third maps 150a to 150c are selected according to the passing powers Pfcvcu and Pbatvcu. However, in the modification of FIG. 22, the correction coefficient k is used instead of selecting the maps 150a to 150c. By using this, the same effects as when the maps 150a to 150c are used can be obtained.

  FIG. 23 is a diagram illustrating an example of a map for setting the correction coefficient k. The horizontal axis of FIG. 23 is a quotient obtained by dividing the passing power Pfcvcu by the passing power Pbatvcu (hereinafter referred to as “quotient Pfcvccu / Pbatvcu”). The vertical axis in FIG. 23 is the correction coefficient k.

  As shown in FIG. 23, when the quotient Pfcvcu / Pbatvcu is small, that is, when the passing power Pbatvcu is relatively large compared to the passing power Pfcvcu, the correction coefficient k is made relatively small. Further, when the quotient Pfccvcu / Pbatvcu increases, that is, when the passing power Pfccvcu relatively increases as compared with the passing power Pbatvcu, the correction coefficient k is increased so as to approach 1.

  In step S86 in FIG. 22, the ECU 30 sets a value obtained by multiplying the temporary target input terminal voltage Vinv_tar_temp by the correction coefficient k as the target input terminal voltage Vinv_tar.

  Steps S87 and S88 are the same as steps S25 and S26 of FIG.

  FIG. 24 shows an example of a time chart when various controls according to the modification of FIG. 22 are used. The difference from the time chart of FIG. 17 according to the above embodiment is that a correction coefficient k is shown instead of the map 150 switching.

  According to the modified example of FIG. 22, the ECU 30 (control device) sets the first map 150a (target input terminal voltage map) when power is supplied from only the FC 50, and when power is supplied only from the FC 50 and the FC 50 In both cases where the power is supplied from both the battery 22 and the battery 22, the temporary target input terminal voltage Vinv_tar_temp is corrected by the correction coefficient k corresponding to the comparison result of the passing powers Pfccvcu and Pbatvcu to calculate the target input terminal voltage Vinv_tar. This eliminates the need to prepare a map 150 for each comparison result. Therefore, the storage capacity for the map 150 can be reduced, and the map 150 can be prepared relatively easily.

10 ... Fuel cell vehicle 12 ... Fuel cell system (electric power system)
14 ... motor 16 ... inverter 22 ... high voltage battery (power storage device)
24 ... Boost converter (first DC / DC converter)
26 ... Buck-boost converter (second DC / DC converter)
30 ... ECU (control device) 50 ... Fuel cell stack (fuel cell)
150a-150e ... 1st-5th map (map for target input terminal voltages)
Emot: Motor power efficiency Ibatvcu ... Passing current of the buck-boost converter (outlet end current)
Ifcvcu: Passing current of the boost converter (exit end current)
k: Correction coefficient Nmot: Motor rotation speed Pbatvcu ... Passing power of step-up / down converter Pfcvcu ... Passing power of boost converter Tmot_req ... Required motor torque Vbat ... Battery voltage (output voltage of power storage device)
Vfc: FC voltage (fuel cell output voltage)
Vinv_tar: Target input terminal voltage (target input voltage) of the inverter
Vmot_req: Requested motor voltage

Claims (5)

A DC power source having a fuel cell and a power storage device arranged in parallel;
A motor,
An inverter that is disposed between the DC power source and the motor, converts DC power from the DC power source into AC power, and supplies the AC power;
A first DC / DC converter disposed between the fuel cell and the inverter and boosting an output voltage of the fuel cell;
A second DC / DC converter disposed between the power storage device and the inverter and stepping up and down an output voltage of the power storage device;
A power system comprising a control device for controlling the first DC / DC converter and the second DC / DC converter,
The controller is
A plurality of target input terminal voltages that define the relationship between the motor rotational speed and the motor torque and the target input terminal voltage of the inverter specified based on the motor rotational speed and the motor torque in consideration of the power efficiency of the motor Set up a map for
The map is switched according to a comparison result of parameters related to passing power or passing power of the first DC / DC converter and the second DC / DC converter,
The power system, wherein the target input terminal voltage corresponding to the motor rotation speed and the motor torque is acquired using the switched map . A DC power source having a fuel cell and a power storage device arranged in parallel;
A motor,
An inverter that is disposed between the DC power source and the motor, converts DC power from the DC power source into AC power, and supplies the AC power;
A first DC / DC converter disposed between the fuel cell and the inverter and boosting an output voltage of the fuel cell;
A second DC / DC converter disposed between the power storage device and the inverter and stepping up and down an output voltage of the power storage device;
A power system comprising a control device for controlling the first DC / DC converter and the second DC / DC converter,
The controller is
The relationship between the motor rotational speed and motor torque when power is supplied only from the fuel cell, and the target input terminal voltage specified based on the motor rotational speed and the motor torque in consideration of the power efficiency of the motor. Set one specified target input terminal voltage map,
The temporary target input terminal voltage, which is the target input terminal voltage in the map, for both the case where electric power is supplied only from the fuel cell and the case where electric power is supplied from both the fuel cell and the power storage device, The target input terminal voltage of the inverter is calculated by correcting with a correction coefficient corresponding to the comparison result of the parameters related to the passing power of the first DC / DC converter and the second DC / DC converter or the passing power. system. The electric power system according to claim 1 or 2,
The control device compares the passing electric power of the first DC / DC converter and the second DC / DC converter or a parameter related to the passing electric power, and compares the outlet end current or the inlet of the first DC / DC converter and the second DC / DC converter. An electric power system characterized by using an end current. In the electric power system according to any one of claims 1 to 3,
The controller is capable of direct connection processing for supplying power from the fuel cell to the inverter without boosting the first DC / DC converter,
When the motor rotation speed and the motor torque are constant, the first DC / DC converter has a smaller passing power or a parameter related to the passing power than the second DC / DC converter. The power system characterized in that the timing of performing the direct connection processing is earlier when the first DC / DC converter has a larger passing power or a parameter related to the passing power than the 2DC / DC converter. The power system according to any one of claims 1 to 4,
The fuel cell vehicle, wherein the motor is a traveling motor.

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