JP4569350B2 - Electric motor system and method for controlling electric motor system - Google Patents

Description

  The present invention relates to an electric motor system including a fuel cell and a control method thereof, and more particularly to a technique for controlling an output response of a drive motor when returning from a predetermined idle stop state to a predetermined idle state.

  Fuel cell technology is a power source or power source that enables clean exhaust and high energy efficiency against recent environmental problems, especially air pollution caused by automobile exhaust gas and global warming caused by carbon dioxide. Attention has been paid. A fuel cell system is an energy conversion system that supplies a fuel gas containing hydrogen and an oxidizing gas such as air to a fuel cell stack to cause an electrochemical reaction to convert chemical energy into electric energy.

  In order to compensate for output responsiveness of a fuel cell, a fuel cell vehicle usually includes a power storage device such as a battery or a capacitor, and operates a motor such as a drive motor by receiving power from the fuel cell or battery. .

Conventionally, as disclosed in Patent Documents 1 and 2, for example, when a vehicle state such as a vehicle speed and a drive motor output and a charging state (remaining capacity) of a power storage device are in a predetermined state, the fuel cell system is It was determined that the engine was in an idle state, and the power generation of the oxidizing gas supply device and the fuel cell stack was stopped to make an idle stop (idle stop state). Further, when the state of charge of the vehicle or the power storage device is not a predetermined state, the oxidant gas supply device is driven to restart the fuel cell stack to supply power.
JP 2001-359204 A JP 2004-056868 A

  However, when the atmospheric pressure around the vehicle decreases or the outside air temperature changes (increases), it is necessary to correct the control necessary for restarting the fuel cell stack. For example, correction for increasing the number of rotations or motor torque of a motor driving each auxiliary device included in the fuel cell system is inevitably performed, and the work amount of each auxiliary device increases. Further, when the environmental conditions and the vehicle state change as described above occur, it may be necessary to limit the operation in order to protect each auxiliary device from overcurrent or the like. In this case, the return time (idle return time) from the idle stop state to idle power generation increases.

  For example, the torque command value of the drive motor is basically designed with a drive motor power consumption response time corresponding to the vehicle speed or the rotation speed of the drive motor in consideration of the idle recovery time at normal time (about 1 atm, normal temperature). Yes. However, when the techniques of Patent Documents 1 and 2 described above are used, the idle recovery time is not estimated but the normal operation is not performed even though the idle recovery time is long due to the environmental conditions and changes in the vehicle state as described above. A torque command is sent to the drive motor. As a result, the output of the drive motor exceeds the power that can be supplied to the drive motor (fuel cell generated power + battery assist power supplied to the vehicle), which may cause overdischarge of the battery.

  Furthermore, if the torque control is performed so that the output of the drive motor is within the power that can be supplied to the drive motor in order to prevent overdischarge of the battery, the driver's intended acceleration cannot be obtained, and the driver has an acceleration feeling. There was also the problem of having a sense of incongruity.

  Accordingly, an object of the present invention is to propose a technique for appropriately controlling the output response time of the drive motor based on the state of the fuel cell at the idle return time.

  In order to solve the above-described problem, the first feature of the present invention is that a drive motor that generates driving force using electric power supplied from the fuel cell and the power storage device and power generation of the fuel cell in idle operation are stopped. Idle stop means for setting an idle stop state, and an idle return for estimating a state estimation value indicating a state of the fuel cell in an idle return time from the start of the start operation of the fuel cell in the idle stop state to the return to the idle operation This is an electric motor system that includes a time state estimation unit and a drive motor output response control unit that controls the output response time of the drive motor based on the state estimation value estimated by the idle return state estimation unit.

  A second feature of the present invention is a method for controlling an electric motor system including a drive motor that generates driving force using electric power supplied from a fuel cell and a power storage device, and stops power generation of the fuel cell in idle operation To estimate the state estimated value indicating the state of the fuel cell in the idle recovery time from the start of the start operation of the fuel cell in the idle stopped state to the return to the idle operation. Based on this, the output response time of the drive motor is controlled.

  ADVANTAGE OF THE INVENTION According to this invention, the electric motor system which controls appropriately the output response time of a drive motor based on the state of the fuel cell in idle return time, and its control method can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(First embodiment)
(Basic configuration)
The basic configuration of the embodiment of the present invention will be described with reference to FIG. A basic configuration of an embodiment of the present invention is an electric motor system including a drive motor that generates driving force using electric power supplied from a fuel cell and a power storage device, and stops power generation of the fuel cell in idle operation. Idle stop means for setting an idle stop state, and an idle return for estimating a state estimation value indicating a state of the fuel cell in an idle return time from the start of the start operation of the fuel cell in the idle stop state to the return to the idle operation The time state estimating means 1 and the drive motor output response control means 4 for controlling the output response time of the drive motor based on the estimated state value estimated by the idling return state estimating means 1 are provided.

  For example, the idle stop means stops the power generation of the fuel cell when the vehicle state is determined to be a predetermined idle state. The idling return state estimating means 1 estimates the state during the return of the fuel cell system from the idling stop state to the idling operation when the fuel cell system is requested to return to idling. The output response time of the drive motor is controlled based on the estimated state value at the time of idling recovery.

  The electric motor system includes a suppliable power calculation means 2 that calculates electric power that can be supplied to the drive motor based on the estimated state value, and a torque change amount of the drive motor based on the estimated state value and the electric power that can be supplied to the drive motor. Further provided is an upper limit torque change amount calculation means 3 for calculating an upper limit. The drive motor output response control means 4 controls the torque of the drive motor based on the upper limit of the torque change amount.

  The suppliable electric power calculating means 2 estimates the electric power that can be supplied to the drive motor in consideration of the rated output of the fuel cell system based on the estimated state value at the time of idling recovery estimated by the idling condition estimation means 1 at the time of idling recovery. The upper limit torque change amount calculating means 3 is based on the estimated state value at the time of idling return estimated by the idling return state estimating means 1 and the estimated value of the power that can be supplied to the drive motor estimated by the suppliable power calculating means 2. Then, the amount of change in the upper limit torque of the optimum drive motor (the upper limit of the amount of torque change) is calculated. The drive motor output response control means 4 controls the change amount of the torque of the drive motor based on the change amount of the upper limit torque calculated by the upper limit torque change amount calculation means 3.

  Here, the “fuel cell” refers to a “single cell”, which is a basic structural unit of a battery configured by a pair of an electrolyte and a pair of electrodes (anode, cathode) provided therebetween. A cell stack, a “cell stack” that is a basic structural unit of a flat plate fuel cell including separators, cooling plates, output terminals, and the like, and a plurality of cell stacks for obtaining a predetermined output. The concept includes a “cell module”. Hereinafter, the “fuel cell” is referred to as a fuel cell stack.

  “Idle operation” refers to a state in which the power is not supplied to the external load but is supplied by itself with the minimum load required for operation (power generation). : JISC8800).

  The “idle stop state” includes a state in which only power generation of the fuel cell stack is stopped from the idle operation, and a state in which the operation of each auxiliary machine constituting the fuel cell system in addition to the fuel cell stack is also stopped from the idle operation. It is. Furthermore, in addition to the fuel cell stack, the operation of each auxiliary machine is also stopped. An auxiliary machine related to the supply of fuel gas, an auxiliary machine related to the supply of oxidizing gas, and an auxiliary machine related to the supply of water for humidifying the reaction gas. This is a concept including a state in which at least one of the operations is stopped.

  The fuel cell stack constitutes a fuel cell system that generates power by supplying a fuel gas containing hydrogen and an oxidizing gas containing oxygen. The fuel cell system includes auxiliary devices for supplying fuel gas, oxidizing gas, cooling water and the like to the fuel cell stack.

  A fuel cell system is a device that directly converts energy of fuel into electrical energy, and supplies a fuel gas containing hydrogen to an anode (anode) of a pair of electrodes provided with an electrolyte membrane interposed therebetween, while An oxidizing gas containing oxygen is supplied to the cathode (cathode), and electric energy is taken out from the electrodes by utilizing an electrochemical reaction of the following formula generated on the surface of the electrolyte membrane side of the pair of electrodes.

Anode reaction: H ₂ → 2H ⁺ + 2e ⁻
Cathode reaction: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O

As the fuel gas supplied to the anode, a method of directly supplying from a hydrogen storage device, a method of supplying a hydrogen-containing gas by reforming a fuel containing hydrogen, and the like are known. As the fuel containing hydrogen, natural gas, methanol, gasoline or the like can be considered. Air is generally used as the oxidizing gas supplied to the cathode.

  In the embodiment of the present invention, when the state of the vehicle is determined to be a predetermined idle state, the oxidizing gas supply device is stopped and the power generation of the fuel cell stack is stopped. In addition, when the vehicle state is determined to be a non-idle state, or when the remaining capacity of the power storage device (for example, the capacitor) is reduced to a predetermined value or less, the oxidant gas supply device is driven to change the fuel cell stack. restart. We propose a drive motor output response control method based on the state estimation of the fuel cell system from the idle stop state to the idle return state that occurs in response to changes in environmental conditions.

  The idle stop means, the idle recovery state estimation means 1, the suppliable power calculation means 2, the upper limit torque change amount calculation means 3, and the drive motor output response control means 4 include a CPU, an input device, an output device, a temporary It can be realized by using a normal information processing apparatus provided with a storage device (main storage device) or the like as a control device (controller).

(First embodiment)
[Constitution]
As shown in FIG. 2, the fuel cell system according to the first embodiment includes a fuel cell stack 11, a humidifier 12 that humidifies fuel gas (hydrogen gas) and oxidizing gas supplied to the fuel cell stack 11, and An oxidizing gas supply device 13 for pumping oxidizing gas, a variable valve 14 for controlling the flow rate of high-pressure hydrogen, a throttle 15 for controlling the pressure and flow rate of oxidizing gas, and a purge valve 16 for discharging hydrogen gas to the outside, A pure water pump 17 for supplying water (for example, pure water) for humidifying the oxidizing gas and hydrogen gas to the humidifier 12, and an ejector 18 for refluxing unused hydrogen discharged from the fuel cell stack 11 upstream. A drive unit 19 for taking out the output from the fuel cell stack 11, an oxidizing gas pressure sensor 20 for detecting the oxidizing gas pressure at the inlet of the fuel cell stack 11, a fuel cell stack A hydrogen pressure sensor 21 that detects the hydrogen pressure at the inlet of the fuel cell 11, an oxidizing gas flow sensor 22 that detects the flow rate of the oxidizing gas flowing into the fuel cell stack 11, and a hydrogen flow rate that detects the flow rate of hydrogen flowing into the fuel cell stack 11. The sensor 23, the cell voltage detection device 25 for detecting the voltage of the single cell or the single cell group from the fuel cell stack 11, the signal of each sensor and the output of the cell voltage detection device 25 are taken in, and based on the built-in control software And a controller 24 for driving each actuator.

  In the oxidizing gas system, the oxidizing gas supply device 13 compresses the oxidizing gas and sends it to the humidifier 12. The humidifier 12 humidifies the oxidizing gas with pure water supplied by the pure water pump 17. The humidified oxidizing gas is sent to the cathode inlet of the fuel cell stack 11.

  In the hydrogen gas system, the flow rate of the hydrogen gas stored in the high-pressure hydrogen tank 26 in a high-pressure state is controlled by the variable valve 14, and at the same time, a desired hydrogen pressure value in the fuel cell stack 11 is set. Further, the hydrogen gas merges with the recirculation amount made of unused hydrogen gas discharged from the fuel cell stack 11 at the ejector 18, and then sent to the humidifier 12, where pure water is supplied in the humidifier 12 in the same manner as the oxidizing gas. It is humidified by the pure water supplied by the pump 17 and then sent to the fuel cell stack 11.

  The fuel cell stack 11 generates electric power by reacting the fed oxidizing gas and hydrogen gas, and supplies current (electric power) to an external system such as a vehicle. The remaining oxidizing gas used for the reaction in the fuel cell stack 11 is discharged out of the fuel cell stack 11. The pressure of the oxidizing gas is controlled by the opening degree of the throttle 15. The remaining hydrogen gas used for the reaction in the fuel cell stack 11 is discharged to the outside of the fuel cell stack 11, but the unused hydrogen gas is returned to the upstream side of the humidifier 12 by the ejector 18 to be regenerated for power generation. Used.

  The oxidizing gas pressure sensor 20 detects the pressure of the oxidizing gas at the cathode inlet of the fuel cell stack 11. The oxidizing gas flow sensor 22 detects the flow rate of the oxidizing gas flowing into the cathode inlet of the fuel cell stack 11. The hydrogen pressure sensor 21 detects the pressure of hydrogen gas at the anode inlet of the fuel cell stack 11. The hydrogen flow rate sensor 23 detects the flow rate of hydrogen gas flowing into the anode inlet of the fuel cell stack 11. The temperature sensor 17 detects the temperature of the atmosphere as an example of an oxidizing gas temperature detecting unit that detects the temperature of the oxidizing gas sucked by the oxidizing gas supply device 13. The cell voltage detection device 25 detects the voltage of a single cell or a single cell group (cell stack) composed of a plurality of single cells constituting the fuel cell stack. These detected values are read into the controller 24. The controller 24 controls the oxidizing gas supply device 13, the throttle 15, and the variable valve 14 so that each read value becomes a predetermined target value determined from the target power generation amount at that time, and from the fuel cell stack 11 to the drive unit. The output (current value) to be output to 19 is commanded and controlled.

  FIG. 3 is a schematic diagram showing a configuration of the entire electric motor system including the fuel cell stack of FIG. The electric motor system includes a fuel cell stack 11, a fuel cell main relay (switch) 31 connected to the fuel cell stack 11, and a DC voltage conversion device 32 that converts electric power generated by the fuel cell stack 11 into a direct current and outputs the direct current. A drive motor inverter 33 connected to the DC voltage converter 32, a drive motor 34 connected to the drive motor inverter 33, and a battery main relay (switch) connected between the drive motor inverter 33 and the drive motor 34. 35, a battery 37 connected to the battery main relay 35, a battery controller 36 for controlling the battery 37, a current sensor 40 for detecting an input current of the DC voltage converter 32, and an input voltage of the DC voltage converter 32. The voltage sensor 41 to detect and the output current of the DC voltage converter 32 are detected. The current sensor 42, the voltage sensor 43 that detects the output voltage of the DC voltage converter 32, the current sensor 44 that detects the output current of the battery 37, the voltage sensor 45 that detects the output voltage of the battery 37, and the atmospheric pressure. It comprises an atmospheric pressure sensor 46 for detecting, an accelerator opening sensor 47 for detecting the accelerator opening, and a controller 24 for taking in the signals of the controllers, inverters and sensors and driving the actuators based on the built-in control software. Is done.

  The electric motor system of FIG. 3 is mounted on a fuel cell vehicle having a fuel cell system as a main power source and a battery as a secondary power source.

  FIG. 4 is a block diagram showing other functional means provided in the controller 24 of FIGS. The controller 24 includes torque / rotation number detection means 51 for detecting the torque and rotation speed of the drive motor 34, upper limit torque calculation means 52 for calculating the upper limit torque of the drive motor 34 based on the rotation speed of the drive motor 34, Based on the rotation speed and torque of the drive motor 34, the power loss estimation means 53 for estimating the power loss of the drive motor 34, and the maximum consumption of the drive motor 34 based on the rotation speed, upper limit torque and power loss of the drive motor 34. And a maximum power consumption calculating means 54 for calculating power. In this case, the upper limit torque change amount calculation means 3 in FIG. 1 calculates the upper limit of the torque change amount of the drive motor 34 based on the power that can be supplied to the drive motor 34 and the maximum power consumption. The drive motor output response control unit 4 in FIG. 1 controls the torque of the drive motor 34 so that the output of the drive motor 34 does not exceed the power that can be supplied to the drive motor 34.

  The atmospheric pressure sensor 46 in FIG. 3 functions as an atmospheric pressure detection unit that detects the atmospheric pressure around the fuel cell stack 11. The idling return state estimating means 1 estimates the estimated state value based on the atmospheric pressure detected by the atmospheric pressure sensor 46. Note that the state estimation value described above may be the idling return time, or may be the power consumption of the auxiliary equipment constituting the fuel cell system during the idling return time.

  As shown in FIG. 4, the electric motor system is a power storage device supply power calculation means (battery supply power calculation means) 55 that calculates the power supply of the power storage device (battery 37) to the drive motor 34 based on the power consumption of the auxiliary machine. Is further provided. In this case, the power that can be supplied to the drive motor 34 is the sum of the rated output of the fuel cell stack 11 and the power supplied to the battery.

[Action]
Next, the operation of the electric motor system according to the first embodiment will be described.

<Main flow chart (Fig. 9)>
First, the overall operation will be described with reference to the flowchart of FIG. The outline of the control method of the electric motor system is to estimate the state of the fuel cell stack 11 at the time of idle return from the atmospheric pressure detected by the atmospheric pressure sensor 46, and consider the state estimated value at the time of idle return to consider the upper limit of the drive motor 34. The amount of change in torque is controlled. 9 is executed every predetermined time (for example, every 10 [ms]) from the start of operation of the electric motor system.

  In step S1, the idling return state estimation means 1 estimates the idling state of the fuel cell system. In step S2, the suppliable power calculation means 2 estimates the power that can be supplied to the drive motor 34 based on the estimated state value at the time of idle recovery estimated in step S1. In step S3, the upper limit torque change amount calculation means 3 calculates the change amount of the upper limit torque of the drive motor 34 based on the estimated value of the electric power that can be supplied to the drive motor 34 estimated in step S2. In step S4, a drive motor torque command value to be commanded to the drive motor inverter 33 is calculated based on the change amount of the upper limit torque calculated in step S3. In step S5, the torque command value for the drive motor calculated in step S4 is commanded to the drive motor inverter 33, and the process ends.

<Idle Return State Estimated Value Calculation Flow Chart -Idle Return Time Estimate- (FIG. 10)>
Here, a method for estimating the state at the time of idle return in the S1 stage of FIG. 9 will be described using the flowchart of FIG. In step S11a, the atmospheric pressure is detected by the atmospheric pressure sensor 46. In step S12a, the idle return time of the fuel cell system is estimated based on the atmospheric pressure detected in step S11a, and the process ends.

Here, a method for estimating the idle return time in step S12a of FIG. 10 will be described with reference to FIG. For example, the relationship between the atmospheric pressure and the correction coefficient for the idle return time of the fuel cell system is obtained in advance through experiments or the like. Further, from FIG. 5A, the idle recovery time correction coefficient when the atmospheric pressure detected by the atmospheric pressure sensor 46 is P _A [kPa] is k _{idle_t} [−]. Further, from FIG. 5B, when the idle return time of the fuel cell system when the atmospheric pressure is 1 atm (= 101.325 kPa) is t _{idle_nor} [sec], the atmospheric pressure is P _A [kPa]. The idle return time t _{idle_Pa} [sec] can be expressed as shown in equation (1).

<Driving motor supplyable power estimation flowchart (FIG. 11)>
Here, a method for estimating the power that can be supplied to the drive motor in step S2 will be described using the flowchart of FIG. In step S21, the assist power from the battery 37 for the drive motor 34 is estimated. In step S22, the rated output (Net) of the fuel cell system is estimated. In step S23, the estimated value of the power that can be supplied to the drive motor is calculated from the sum of the battery assist power estimated in step S21 and the rated output (Net) of the fuel cell system estimated in step S22.

Here, a battery assist power estimation method for the drive motor 34 in step S21 in FIG. 11 will be described. For example, the maximum value of the battery assist power transmitted from the battery controller 36 is Batt _MAX [kW], the power consumption of the fuel cell system auxiliary machine during idle recovery is P _{PP_idle_aux_nor} [kW], and the power consumption of the vehicle auxiliary machine is P _{Assuming that V_idle_aux} [kW], the battery assist power Batt _MTR [kW] for the drive motor 34 can be expressed as in equation (2).

Here, the fuel cell system rated output (Net) estimation method in step S22 of FIG. 11 will be described with reference to FIG. For example, if the fuel cell stack output (Gross) G _gross [kW] is experimentally determined beforehand and the power consumption of the fuel cell system auxiliary machine for realizing the output is P _{PP_aux} [kW], the fuel cell system output ( Net) G _net [kW] can be expressed as shown in equation (3).

In addition, FIG. 6 shows the maximum value G _{max_net} [kW] of the rated output (Net) of the fuel cell system expressed by the equation (3). Only the battery assist power is used for the power consumption of the auxiliary machine until the predetermined idle return time t _{idle_Pa} after the command for returning to idle is issued. After the predetermined idle return time t _{idle_Pa} , the output G _net [kW] of the fuel cell system rises, and at the same time, the drive motor _supplyable power MTR _supply [kW] also rises.

Here, a method for estimating the power that can be supplied to the drive motor in step S23 in FIG. 11 will be described with reference to FIG. From the battery assist power Batt _MTR [kW] calculated in step S21 and the fuel cell system output (Net) G _net [kW] calculated in step S22, an estimated value MTR _supply [ kW] can be expressed as in equation (4).

<Optimum drive motor upper limit torque change amount calculation flowchart (FIG. 12)>
Next, a method of calculating the amount of change in the upper limit torque of the drive motor 34 in step S3 in FIG. 9 will be described using the flowchart in FIG. In step S31, a change correction coefficient for the upper limit torque of the drive motor 34 at the time of idling return is calculated. In step S32, a change amount for the upper limit torque is calculated based on the change correction coefficient for the upper limit torque calculated in step S31. To finish.

Here, an example of a method of calculating the upper limit torque variation correction coefficient in step S31 will be described with reference to FIG. The relationship between the idle recovery time correction coefficient calculated in step S12a of FIG. 10 and the upper limit torque variation correction coefficient is obtained in advance through experiments or the like. When the idle recovery time correction coefficient is k _{idle_t} [-], the upper limit torque variation correction coefficient corresponding to the idle recovery time correction is k _{idle_upperdTr_t} [-].

Here, a method for calculating the amount of change in the upper limit torque in step S32 in FIG. 12 will be described. When the idle recovery time of the fuel cell system is t _{idle_nor} [sec], if the amount of change in the upper limit torque is _{ΔTr idle_nor} [Nm / sec], the upper limit torque when the idle recovery time is t _{idle_Pa} [sec] The amount of change _{ΔTr idle_Pa} [Nm / sec] can be expressed as in equation (5).

Next, a method for calculating the drive motor torque command value in step S4 in FIG. 9 will be described with reference to FIG. The driver required torque corresponding to the accelerator opening detected by the accelerator opening sensor 47 and the drive motor inverter 33 and the drive motor speed is Tr _target [Nm], and the change amount of the driver required torque Tr _target [Nm] is ΔTr _Target [Nm / sec]

When △ Tr _target ≧ △ Tr _{idle_Pa} , the change amount of the driver request torque Tr _target [Nm] is limited by the optimum upper limit torque change amount △ Tr _{idle_Pa} [Nm / sec], and the drive motor inverter 33 Torque command value △ Tr _{target_lmt} [Nm] is transmitted.

If _{ΔTr target} < _{ΔTr idle_Pa} , the torque command value Tr _target [Nm] is transmitted to the drive motor inverter 33 as requested by the driver.

The drive motor rotation speed detected by the drive motor inverter 33 is N _MTR [rpm], and the drive motor loss based on the rotation speed N _MTR [rpm] and the torque command value Tr _{target_lmt} [Nm] to the drive motor 34 is _calculated . If Loss _MTR (M _MTR , Tr _{target_lmt} ) [kW], the power consumption W _{MTR_lmt} [kW] of the drive motor 34 can be expressed as in equation (6).

Furthermore, the idle recovery time correction coefficient k _{idle_t} [−] and the idle power are set so that the power consumption W _MTR [kW] of the drive motor 34 does not exceed the drive motor _suppliable power MTR _supply [kW] shown in FIG. The relationship with the correction coefficient k _{idle_upper_dTr} [-] of the change amount of the upper limit torque at return is obtained.

[effect]
As described above, in the electric motor system according to the first embodiment, the drive motor output response control means 4 is based on the estimated state value indicating the state of the fuel cell stack 11 during the idle recovery time. Controls output response time. As a result, the output response time of the drive motor 34 can be appropriately controlled based on the state of the fuel cell stack 11 at the idle return time, and the acceleration feeling for the driver can be further increased without causing the battery 37 to overdischarge. Discomfort can be alleviated <Effects of Claims 1 and 8>.

  The upper limit torque change amount calculation means 3 calculates the upper limit of the torque change amount of the drive motor 34, and the drive motor output response control means 4 controls the torque of the drive motor 34 based on the upper limit of the torque change amount. That is, since the upper limit torque change amount of the drive motor 34 is controlled by estimating the state when the fuel cell system is returned to the idle state, the battery 37 is not overdischarged, and the driver feels uncomfortable with the acceleration feeling. <Effects of claims 2 and 9>

  The upper limit value of the change amount of the drive motor torque command value is calculated from the power that can be supplied to the drive motor 34 and the power consumption of the drive motor 34 in accordance with the rotational speed of the drive motor 34. Thereby, the uncomfortable feeling of acceleration feeling to the driver can be further alleviated without excessively limiting the output of the drive motor 34 and without causing overdischarge of the battery 37. <Effect of Claim 3>

  The idling return state estimating means 1 estimates the estimated state value based on the atmospheric pressure. Thereby, even when the atmospheric pressure changes, it is possible to estimate the idling return state (state estimated value) with high accuracy <effect of claim 4>.

  By setting the estimated state value to the idle return time, the drive motor 34 can be controlled without causing the battery 37 to overdischarge even when the idle return time changes. .

(Second Embodiment)
[Constitution]
The description regarding FIG. 1 to FIG. 8, FIG. 11, and FIG. 12 is the same as that of the first embodiment, and will be omitted.

[Action]
The general operation is the same as that of the first embodiment.

<Idle recovery state estimated value calculation flowchart-Auxiliary power consumption estimation-(FIG. 16)>
A method for estimating the state of the fuel cell stack at the time of idling return in step S1 of FIG. 9 will be described using the flowchart of FIG. In step S11b, the atmospheric pressure is detected by the atmospheric pressure sensor 46, and in step S12b, the idle recovery time of the fuel cell system is estimated based on the atmospheric pressure detected in step S11b. In step S13b, the power consumption of the auxiliary fuel cell system is estimated based on the atmospheric pressure detected in step S11b, and the process ends.

  Note that the method for estimating the idle recovery time in step S12b is the same as that in step S12a of FIG. 10 described in the first embodiment, and is therefore omitted here.

The auxiliary power consumption estimation method in step S12b of FIG. 16 will be described with reference to FIG. For example, as shown in FIG. 8A, the relationship between the atmospheric pressure and the correction coefficient of the auxiliary power consumption of the auxiliary fuel cell system is obtained in advance through experiments or the like. Further, the correction coefficient for the auxiliary machine power consumption when the atmospheric pressure detected by the atmospheric pressure sensor 46 is P _A [kPa] is k _{idle_p} [−]. Further, from FIG. 8B, the auxiliary machine power consumption of the fuel cell system when the atmospheric pressure is 1 atm (= 101.325 kPa) is _{defined as PP_idle_aux_nor} [kW]. In this case, the auxiliary machine power consumption P _{PP_idle_aux_Pa} [kW] when the atmospheric pressure is P _A [kPa] can be expressed as the following equation (7).

  Further, the estimation method of the drive motor suppliable power in the step S2 in FIG. 9 and the flowchart in FIG. 11 are the same as the estimation method in the step S12a in FIG. 10 described in the first embodiment. Only the battery assist power estimation method for the drive motor in step S21 of FIG. 11 will be described.

For example, the maximum value of the battery assist power transmitted from the battery controller 36 is Batt _max [kW], and the power consumption of the vehicle auxiliary machine is P _{V_idle_aux} [kW]. In this case, the battery assist power Batt _MTR [kW] for the drive motor 34 from the auxiliary machine power consumption P _{PP_idle_aux_Pa} [kW] at the atmospheric pressure P _A [kPa] calculated in the step S12b is expressed by the following equation (8). be able to.

FIG. 14 shows the rated output (Net) G _{max_net} [kW] of the fuel cell system expressed by the equations (3) and (8) described in the method of estimating the fuel cell system rated output (Net) in step S22. .

  Further, the calculation method of the optimum drive motor upper limit torque change amount in step S3 in FIG. 9 and the flowchart in FIG. 12 are the same as the calculation method described in the first embodiment, and thus the description thereof is omitted. Here, only the method for calculating the variation correction coefficient for the upper limit torque at the time of idling return in step S31 in FIG. 12 and the method for calculating the upper limit torque variation in step S32 will be described.

The relationship between the correction coefficient for the auxiliary machine power consumption at the time of idling return calculated in step S12b in FIG. 16 and the correction coefficient for the upper limit torque change amount of the drive motor at the time of idling return is obtained through experiments or the like in advance. Further, when the correction coefficient for the auxiliary machine power consumption at the time of returning to the idle state is k _{idle_p} [-], the change amount correction coefficient for the upper limit torque of the drive motor 34 corresponding to the auxiliary machine power consumption is set to k _{idle_upperdTr_p} [-]. . Further, when the idle recovery time correction coefficient calculated in step S31 of FIG. 12 is k _{idle_t} [-], the change correction coefficient of the upper limit torque of the drive motor 34 corresponding to the idle recovery time is k _{idle_upperdTr_t} [-]. Therefore, the correction coefficient k _{idle_upperdTr} [−] of the upper limit torque change amount of the drive motor 34 can be expressed by the following equation (9).

_{Let ΔTr idle_nor} [Nm / sec] be the upper limit torque change amount of the drive motor 34 when the idle return time of the fuel cell system is t _{idle_nor} [sec]. At this time, the optimum drive motor upper limit torque change _{ΔTr idle_Pa} [Nm / sec] in the idle return time t _{idle_Pa} [sec] can be expressed as the following equation (10).

  Finally, the torque command is transmitted to the drive motor inverter 33 by the same calculation method as the calculation method of the drive motor torque command value in step S4 of FIG. 9 described in the first embodiment.

[effect]
As described above, in the electric motor system according to the second embodiment, by assuming that the state estimation value is the power consumption of the auxiliary machine constituting the fuel cell system at the idle return time, the power consumption of the auxiliary machine is reduced. Even in the case of a change, the drive motor 34 can be controlled without causing overdischarge of the battery 37 <Effect of Claim 6>.

  Assume that the power that can be supplied to the drive motor 34 is the sum of the rated output of the fuel cell stack 11 and the battery supply power. That is, since the power that can be supplied is calculated by the sum of the battery supply power considering the power consumption of the auxiliary machine and the rated output of the fuel cell system, the drive motor 34 does not cause overdischarge of the battery 37. <Effect of claim 7>.

(Other embodiments)
As described above, the present invention has been described according to the first and second embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

In the first embodiment, the case where the idle return time t _idle is corrected as shown in FIG. 5B will be described, and in the second embodiment, the _idle return time t _idle as shown in FIG. The case where not only the return time t _idle but also the power consumption P _{pp_idle_aux} of the auxiliary machine is corrected has been described. The present invention is not limited to this. For example, the correction may be made only for the power consumption P _{pp_idle_aux} of the auxiliary machine, and the correction may not be made for the idle return time t _idle .

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

It is a figure which shows the basic composition of embodiment of this invention. 1 is a block diagram showing a fuel cell system according to a first embodiment. It is a block diagram which shows the structure of the whole electric motor system containing the fuel cell stack of FIG. FIG. 4 is a block diagram illustrating a configuration of a controller illustrated in FIGS. 2 and 3. It is a figure explaining an example of an idle return time estimation method, (a) is a graph which shows the relationship between atmospheric pressure and the correction coefficient of idle return time, (b) is a graph of idle return time and fuel cell system output. It is a graph which shows a relationship. It is a graph explaining the method of estimating the electric power which can supply a drive motor at the time of idling return. It is a graph which shows the relationship between the correction coefficient of idle return time, and the correction coefficient of upper limit torque variation | change_quantity. It is a graph for demonstrating the method of estimating the electric power which can supply a drive motor at the time of idling return. It is a flowchart which shows the whole control method of the electric motor system concerning the 1st Embodiment of this invention. It is a flowchart which shows the method of calculating the state estimated value (idle return time) at the time of idling return. It is a flowchart which shows the method of estimating electric power which can supply a drive motor. It is a flowchart which shows the method of calculating the variation | change_quantity of the optimal upper limit torque of a drive motor. It is a figure for demonstrating the method of estimating the auxiliary machine power consumption at the time of idling return, (a) is a graph which shows the relationship between atmospheric pressure and the correction coefficient of auxiliary machine power consumption, (b) is atmospheric pressure. It is a graph which shows the auxiliary machine power consumption at the time of idling return which uses as a parameter. It is a graph for demonstrating the method of estimating the electric power which can be supplied to a drive motor at the time of idling return. It is a graph which shows the relationship between the correction coefficient of auxiliary machine power consumption at the time of idling return, and the correction coefficient of drive motor upper limit torque variation. It is a flowchart which shows the method of calculating the state estimated value (auxiliary machine power consumption) at the time of idling return.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... State estimation means at the time of idle return 2 ... Supplyable electric power calculation means 3 ... Upper limit torque change amount calculation means 4 ... Drive motor output response control means 11 ... Fuel cell stack 12 ... Humidifier 13 ... Oxidizing gas supply device 14 ... Variable valve DESCRIPTION OF SYMBOLS 15 ... Throttle 16 ... Purge valve 17 ... Temperature sensor 17 ... Pure water pump 18 ... Ejector 19 ... Drive unit 20 ... Oxidation gas pressure sensor 21 ... Hydrogen pressure sensor 22 ... Oxidation gas flow sensor 23 ... Hydrogen flow sensor 24 ... Controller 25 ... Cell voltage detector 26 ... High-pressure hydrogen tank 32 ... DC voltage converter 33 ... Drive motor inverter 34 ... Drive motor 35 ... Battery main relay 36 ... Battery controller 37 ... Battery 40, 42, 44 ... Current sensors 41, 43, 45 ... Voltage sensor 46 ... Atmospheric pressure sensor 47 ... Accelerator Degree sensor 51 ... torque rotational speed detecting means 52 ... upper limit torque calculating means 53 ... power loss estimation means 54 ... maximum power consumption calculating unit

Claims (9)

A driving motor that generates driving force using electric power supplied from the fuel cell and the power storage device;
Idle stop means for stopping power generation of the fuel cell in idle operation to be in an idle stop state;
Idle recovery state estimation means for estimating a state estimated value indicating a state of the fuel cell in an idle recovery time from the start of starting the fuel cell in the idle stop state to the return to idle operation;
An electric motor system comprising: drive motor output response control means for controlling an output response time of the drive motor based on the estimated state value estimated by the idle return state estimating means. Suppliable power calculating means for calculating electric power that can be supplied to the drive motor based on the estimated state value;
An upper limit torque change amount calculating means for calculating an upper limit of the torque change amount of the drive motor based on the state estimated value and the suppliable power;
2. The electric motor system according to claim 1, wherein the drive motor output response control means controls the torque of the drive motor based on an upper limit of the torque change amount. Torque / rotation number detecting means for detecting the torque and the rotation speed of the drive motor;
Upper limit torque calculating means for calculating an upper limit torque of the drive motor based on the rotational speed;
Based on the rotation speed and the torque, a loss power estimation means for estimating a loss power of the drive motor;
Maximum power consumption calculating means for calculating the maximum power consumption of the drive motor based on the rotation speed, the upper limit torque and the power loss,
The upper limit torque change amount calculation means calculates an upper limit of the torque change amount of the drive motor based on the power that can be supplied and the maximum power consumption,
3. The electric motor system according to claim 2, wherein the drive motor output response control means controls the torque so that the output of the drive motor does not exceed the power that can be supplied. Further comprising atmospheric pressure detection means for detecting atmospheric pressure around the fuel cell;
2. The electric motor system according to claim 1, wherein the state estimation means at the time of idle recovery estimates the state estimated value based on the atmospheric pressure.   The electric motor system according to claim 4, wherein the estimated state value is the idle recovery time.   5. The electric motor system according to claim 4, wherein the estimated state value is power consumption of an auxiliary machine constituting the fuel cell system at the idle return time. Based on the power consumption of the auxiliary machine, further comprises a power storage device supply power calculation means for calculating the power supply of the power storage device to the drive motor,
7. The electric motor system according to claim 3, wherein the power that can be supplied is a sum of a rated output of the fuel cell and power supplied to the power storage device. A method for controlling an electric motor system including a driving motor that generates driving force using electric power supplied from a fuel cell and a power storage device,
Stop the power generation of the fuel cell in idle operation to idle idle state,
Estimating a state estimation value indicating a state of the fuel cell in an idle return time from the start of the start operation of the fuel cell in the idle stop state to the return to idle operation,
A control method for an electric motor system, wherein an output response time of the drive motor is controlled based on the estimated state value. Calculate power that can be supplied to the drive motor based on the estimated state value,
Based on the estimated state value and the power that can be supplied, the upper limit of the torque change amount of the drive motor is calculated,
9. The motor system control method according to claim 8, wherein controlling the output response time of the drive motor is controlling the torque of the drive motor based on an upper limit of the torque change amount.

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