JP2013033611A - Fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rapid deterioration of responsiveness caused by switching feedback modes in which a power feedback control mode and a voltage feedback control mode are switched according to an operational status in a converter control of a fuel battery system.SOLUTION: A fuel battery system 1 comprises: a converter 10 which is provided between a fuel battery 2 and a loading device; and control means 7 which controls an operation of the converter 10. The control means 7 controls the converter 10 by switching between a power feedback control mode which controls the operation of the converter 10 according to output power of the fuel battery 2 and a voltage feedback control mode which controls the operation of the converter 10 according to an output voltage of the fuel battery 2. When a difference between feedback variables before and after switching is a prescribed threshold value or more, the feedback variable is gradually changed from the feedback variable before switching to the feedback variable after switching.

Description

  The present invention relates to a fuel cell system.

  2. Description of the Related Art Conventionally, there has been proposed a hybrid power supply apparatus configured by mounting a fuel cell that receives a supply of reaction gas (fuel gas and oxidizing gas) and generates power together with a secondary battery such as a storage battery. For example, a main power supply unit (fuel cell), an auxiliary power supply unit (battery), and a voltage adjustment unit (such as a DC-DC converter) that adjusts and outputs an output voltage of the main power supply unit to a predetermined DC voltage. A hybrid power supply apparatus has been conventionally proposed (see Patent Document 1). The voltage adjustment unit of such a device is configured to operate in either the feedforward drive mode or the feedback drive mode according to the operation parameter of the main power supply unit.

JP 2008-178287 A

  By the way, at present, a technique for providing a high-power multiphase converter for converting a DC voltage supplied from a fuel cell into a larger DC voltage in a hybrid power supply apparatus including a fuel cell has been proposed. In such a multiphase converter, feedback control is employed to adjust the duty ratio of the switching element of each drive phase.

  In recent years, development of multiphase converter control that switches between a power feedback control mode and a voltage feedback control mode in accordance with the operating state of the system has been underway. Such switching control controls the multiphase converter according to the output power of the fuel cell in a normal operating state (power feedback control mode), while the output voltage of the fuel cell exceeds the upper limit (or exceeds the lower limit). In such an operating state, the multiphase converter is controlled according to the output voltage (voltage feedback control mode).

  However, in the switching control as described above, when switching from the power feedback control mode to the voltage feedback control mode (or from the voltage feedback control mode to the power feedback control mode), there is a gap between the feedback variables before and after the switching. There is. Thus, if there is a gap between the feedback variables before and after the switching, for example, the DC voltage supplied by the multiphase converter rapidly decreases after the switching of the feedback mode, and as a result, the responsiveness of the output power of the fuel cell to the required power is reduced. The problem of a sharp drop can occur.

  The present invention has been made in view of such circumstances, and when switching between the power feedback control mode and the voltage feedback control mode in accordance with the operation state in the converter control of the fuel cell system, the rapid change caused by the switching of the feedback mode. It is intended to suppress a significant decrease in responsiveness.

  In order to achieve the above object, a fuel cell system according to the present invention is a fuel cell system comprising a converter provided between a fuel cell and a load device, and control means for controlling the operation of the converter. The control means switches between a power feedback control mode for controlling the operation of the converter based on the output power of the fuel cell and a voltage feedback control mode for controlling the operation of the converter based on the output voltage of the fuel cell. If the feedback variable before and after switching has a difference greater than a predetermined threshold, the feedback variable is gradually changed from the feedback variable before switching to the feedback variable after switching.

  When such a configuration is adopted, when switching from the power feedback control mode to the voltage feedback control mode (or from the voltage feedback control mode to the power feedback control mode), the feedback variable before and after the switching has a difference of a predetermined threshold value or more. Even in the case, the feedback variable can be gradually changed. Therefore, it is possible to suppress a rapid decrease in responsiveness due to the difference between the feedback variables before and after switching.

  In the fuel cell system according to the present invention, the change rate of the feedback variable when switching from the power feedback control mode to the voltage feedback control mode, and the change rate of the feedback variable when switching from the voltage feedback control to the power feedback control. Different control means can be employed. For example, the change rate of the feedback variable when switching from the voltage feedback control to the power feedback control can be set larger than the change rate of the feedback variable when switching from the power feedback control mode to the voltage feedback control mode.

Further, in the fuel cell system according to the present invention, the feedback variables in the power feedback control mode and the current correction value I _P, the feedback variable in the voltage feedback control mode and a current correction value I _V, the switching rate α (0 <α < In the case of 1), a current correction value I as a feedback variable to be changed is expressed by the following formula: I = α × I _P + (1−α) × I _V
It is possible to employ control means for calculating by the above.

  In the fuel cell system according to the present invention, when the switching from the power feedback control mode to the voltage feedback control mode is completed, the feedback variable in the power feedback control mode is initialized (set to a predetermined initial value). Control means can be employed. Similarly, it is possible to employ control means for initializing (setting to a predetermined initial value) the feedback variable in the voltage feedback control mode when the switching from the voltage feedback control mode to the power feedback control mode is completed.

  By adopting such a configuration, it is possible to suppress a decrease in responsiveness due to accumulation of correction terms.

  Further, in the fuel cell system according to the present invention, an integral feedback gain is employed when calculating a feedback variable in each feedback control mode, and the calculated feedback variable exceeds a predetermined upper limit value (or a predetermined lower limit value). The integral feedback gain can be set to zero (accumulation of the integral term can be stopped).

  By adopting such a configuration, it is possible to more effectively suppress a decrease in responsiveness.

  According to the present invention, when switching between the power feedback control mode and the voltage feedback control mode in accordance with the operating state in the converter control of the fuel cell system, it is possible to suppress a rapid decrease in responsiveness caused by the switching of the feedback mode. Is possible.

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a block diagram for demonstrating FC converter control of the fuel cell system shown in FIG. It is a time chart which shows the time history of the feedback mode flag in FC converter control of the fuel cell system shown in FIG. It is a time chart which shows the time history of the switching rate of the feedback variable in FC converter control of the fuel cell system shown in FIG. It is a time chart which shows the time history of the feedback mode switching state in FC converter control of the fuel cell system shown in FIG.

  Hereinafter, a fuel cell system 1 according to an embodiment of the present invention will be described with reference to the drawings. The fuel cell system 1 according to the present embodiment is a power generation system mounted on a fuel cell vehicle.

  As shown in FIG. 1, the fuel cell system 1 rotates the traction motor 5 by supplying electric power generated by the fuel cell 2 and the battery 3 to the traction motor 5 via the inverter 4. . The fuel cell system 1 includes an FC converter 10 provided between the fuel cell 2 and the inverter 4, a battery converter 6 provided between the battery 3 and the inverter 4, a controller 7 for integrally controlling the entire system, and the like. ing.

  The fuel cell 2 is a solid polymer electrolyte type cell stack configured by stacking a plurality of single cells in series. In the fuel cell 2, an oxidation reaction of the following formula (1) occurs in the anode electrode, and a reduction reaction of the following formula (2) occurs in the cathode electrode, and the fuel cell 2 as a whole has the following formula (3). An electrical reaction occurs.

H ₂ → 2H ⁺ + 2e ⁻ (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
H ₂ + (1/2) O ₂ → H ₂ O (3)

  The unit cell constituting the fuel cell 2 is a separator for supplying a fuel gas and an oxidizing gas to a membrane / electrode assembly (MEA) formed by sandwiching a polymer electrolyte membrane between two electrodes, an anode electrode and a cathode electrode. It has a structure sandwiched between. The fuel cell 2 is provided with a system for supplying the fuel gas to the anode electrode, a system for supplying the oxidizing gas to the cathode electrode, and a system for supplying the cooling liquid into the separator, and according to a control signal from the controller 7. By controlling the supply amount of the fuel gas and the supply amount of the oxidizing gas, desired power can be generated.

  The FC converter 10 functions to control the output voltage of the fuel cell 2. As shown in FIG. 1, the FC converter 10 in the present embodiment is a multiphase converter in which four phases of a U-phase converter 11, a V-phase converter 12, a W-phase converter 13, and an X-phase converter 14 are connected in parallel. The FC converter 10 uses one phase driving that uses only one phase (for example, U phase) and two phases (for example, U phase and V phase) according to the load (required power) of a load device such as the traction motor 5. The drive phase can be switched such as two-phase drive, three-phase drive using three phases (for example, U phase, V phase, and W phase) and four-phase drive using all the drive phases. .

  The FC converter 10 controls the output voltage of the fuel cell 2 to be a voltage corresponding to the target output. The output voltage and output current of the FC converter 10 can be detected by a voltage sensor and a current sensor not shown. Moreover, in this embodiment, the reactor current sensor for detecting the electric current (reactor current) which flows into the reactor of each drive phase is provided.

  Examples of switching elements used for each drive phase (U phase, V phase, W phase, X phase) of the FC converter 10 include a junction Schottky diode, a pin / Schottky composite diode, and a MOS barrier. Diodes such as Schottky diodes, current control type transistors such as bipolar junction transistors (BJT) and Darlington, thyristors such as normal thyristors and GTO (Gate Turn Off) thyristors, MOS field effect (FET) transistors, insulated gate bipolar types Examples thereof include a voltage control type transistor such as a transistor (IGBT) and an injection promotion type insulated gate transistor (IEGT). Of these, thyristors and voltage-controlled transistors are preferable.

  The battery 3 is connected in parallel to the fuel cell 2 with respect to the traction motor 5 and has a function of storing surplus power and regenerative energy during regenerative braking, and at the time of load fluctuation accompanying acceleration or deceleration of the fuel cell vehicle. It functions as an energy buffer. As the battery 3, for example, a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery can be employed.

  The battery converter 6 fulfills the function of controlling the input voltage of the inverter 4. For example, a battery converter having the same circuit configuration as that of the FC converter 10 can be adopted. As the battery converter 6, a step-up converter may be employed, but instead, a step-up / step-down converter capable of a step-up operation and a step-down operation may be employed, and the input voltage of the inverter 4 can be controlled. Any configuration can be adopted.

  The inverter 4 can employ, for example, a PWM inverter driven by a pulse width modulation method, and converts DC power supplied from the fuel cell 2 or the battery 3 into three-phase AC power in accordance with a control command from the controller 7. Thus, the rotational torque of the traction motor 5 is controlled.

  The traction motor 5 generates rotational torque that serves as power for the fuel cell vehicle, and is also configured to generate regenerative power during deceleration. The rotational torque of the traction motor 5 is transmitted to the tire 9 through the shaft 8a after being decelerated to a predetermined rotational speed by the reduction gear 8. In the present embodiment, all devices (including the traction motor 5 and the speed reduction device 8) that operate by receiving power supplied from the fuel cell 2 are collectively referred to as a load device.

  The controller 7 is a computer system for integrated control of the fuel cell system 1 and includes, for example, a CPU, a RAM, a ROM, and the like. The controller 7 receives inputs of signals (for example, a signal indicating the accelerator opening, a signal indicating the vehicle speed, a signal indicating the output current and output voltage of the fuel cell 2) supplied from various sensors, and loads the load on the load device. (Required power) is calculated.

  The load of the load device is, for example, a total value of the vehicle traveling power and the auxiliary power. Auxiliary power is the power consumed by in-vehicle auxiliaries (air compressors, hydrogen pumps, cooling water circulation pumps, etc.) and equipment required for vehicle travel (transmissions, wheel control devices, steering devices, suspension devices, etc.) Power consumed, power consumed by devices (air conditioners, lighting fixtures, audio, etc.) arranged in the passenger space are included.

  And the controller 7 determines distribution of each output electric power of the fuel cell 2 and the battery 3, and calculates an electric power generation command value. When the controller 7 calculates the required power for the fuel cell 2 and the battery 3, the controller 7 controls the operations of the FC converter 10 and the battery converter 6 so that these required powers are obtained. That is, the controller 7 functions as control means in the present invention.

  In the present embodiment, the controller 7 controls the operation of the FC converter 10 in the “power feedback control mode” for controlling the operation of the FC converter 10 based on the output power of the fuel cell 2, and the output voltage of the fuel cell 2. The “voltage feedback control mode” for controlling the operation of the FC converter 10 based on the above is performed.

  Here, the details of the FC converter control by the controller 7 will be described with reference to FIGS.

<Power feedback control mode>
First, the “power feedback control mode” for controlling the operation of the FC converter 10 based on the output power of the fuel cell 2 will be described. The controller 7 monitors the operating state of the fuel cell 2 and adopts a power feedback control mode when controlling the operation of the FC converter 10 in a normal operating state.

First, the controller 7 calculates the power command value P _REF based on the required power and the like, and detects the output power P _MES of the fuel cell 2. Then, as shown in FIG. 2, the controller 7 performs power feedback based on the deviation (P _REF −P _MES ) of the output power P _MES with respect to the power command value P _REF and the power feedback gain K _{FB — P.} A current correction value I _P is calculated.

Next, the controller 7 adds the current correction value I _P by power feedback to the current command value I _REF calculated based on the required power or the like, thereby correcting the current command value I _{REF — P} (= I _REF + I _P ) is calculated, and the output current I _MES of the fuel cell 2 is detected. Then, the controller 7 determines the power based on the deviation (I _{REF — P} −I _MES ) of the output current I _MES with respect to the current command value I _{REF — P} corrected by the power feedback, and the current feedback gain K _{FB — I.} • Calculate the duty term D _FB _ _P by current feedback. Further, the controller 7 calculates a duty term D _{FF — P} by power feedback / current feed forward by multiplying the current command value I _{REF — P} corrected by power feedback by a current feed forward gain K _{FF — I.}

Thereafter, the controller 7 adds the duty term D _{FB — P} due to power / current feedback and the duty term D _{FF — P} due to power feedback / current feedforward, thereby adding a duty command value D (= D _FB based on power feedback). _ _P + D _FF _ _P) is calculated, to control the operation of the FC converter 10 with the duty command value D. As various feedback gains (power feedback gain K _{FB — P} and current feedback gain K _{FB — I} ), a proportional gain or an integral gain can be employed.

<Voltage feedback control mode>
Next, the “voltage feedback control mode” for controlling the operation of the FC converter 10 based on the output voltage of the fuel cell 2 will be described. The controller 7 monitors the operation state of the fuel cell 2, and operates the FC converter 10 in a special operation state in which the output voltage of the fuel cell 2 exceeds a predetermined upper limit value (or falls below a predetermined lower limit value). Adopt voltage feedback control mode when controlling. The voltage feedback control mode is for the purpose of suppressing deterioration of the fuel cell 2 and ensuring minimum power.

First, the controller 7 calculates the voltage command value V _REF in consideration of the specifications (upper limit voltage value and lower limit voltage value) of the fuel cell 2 and detects the output voltage V _MES of the fuel cell 2. Then, as shown in FIG. 2, the controller 7 performs voltage feedback based on the deviation (V _REF −V _MES ) of the output voltage V _MES with respect to the voltage command value V _REF and the voltage feedback gain K _{FB — V.} A current correction value I _V is calculated.

Next, the controller 7 adds the current correction value I _V by voltage feedback to the current command value I _REF calculated based on the required power or the like, thereby correcting the current command value I _{REF — V} (= I _REF + I _V ) is calculated, and the output current I _MES of the fuel cell 2 is detected. Then, the controller 7 determines the voltage based on the deviation (I _{REF — V} −I _MES ) of the output current I _MES with respect to the current command value I _{REF — V} corrected by voltage feedback, and the current feedback gain K _{FB — I.} • Calculate the duty term D _FB _ _V by current feedback. Further, the controller 7 calculates a duty term D _{FF — V} by voltage feedback / current feed forward by multiplying the current command value I _{REF — V} corrected by voltage feedback by a current feed forward gain K _{FF — I.}

After that, the controller 7 adds the duty term D _{FB — V} based on voltage / current feedback and the duty term D _{FF — V} based on voltage feedback / current feedforward to add a duty command value D (= D _FB based on voltage feedback). _ _V + D _FF _ _V) is calculated, and controls the operation of the FC converter 10 with the duty command value D. As the voltage feedback gain K _{FB — V} , a proportional gain or an integral gain can be adopted.

<Feedback mode switching control>
Next, feedback mode switching control will be described. The controller 7 adopts a power feedback control mode to control the operation of the FC converter 10 in a normal operation state, while the output voltage of the fuel cell 2 exceeds a predetermined upper limit value (or falls below a predetermined lower limit value). In such a special operating state, the voltage feedback control mode is adopted to control the operation of the FC converter 10.

When the controller 7 determines that the operation state of the fuel cell 2 has shifted from a normal operation state to a special operation state, the controller 7 outputs a switching signal _SS to switch from the power feedback control mode to the voltage feedback control mode. The control mode of the FC converter 10 is switched. It should be noted that the controller 7 is normal when the output voltage of the fuel cell 2 exceeds a predetermined upper limit value (for example, 300V) or when the output voltage of the fuel cell 2 falls below a predetermined lower limit value (for example, 150V). It can be determined that the operating state has shifted to the special operating state.

When the controller 7 switches from the power feedback control mode to the voltage feedback control mode, the deviation ΔI (= I) of the feedback variable (current correction value I _V ) after switching with respect to the feedback variable (current correction value I _P ) before switching. _P− I _V ) is calculated in absolute value. When the absolute value of the deviation ΔI is equal to or greater than a predetermined threshold, the controller 7 feeds back from the feedback variable (current correction value I _P ) before switching to the feedback variable (current correction value I _V ) after switching. Change the variable gradually.

Further, the controller 7 when the operation state of the fuel cell 2 is determined that a transition from the special operating conditions in normal operating conditions is also outputs a switching signal S _S, the power feedback control from the voltage feedback control mode The control mode of the FC converter 10 is switched to the mode. Also at this time, the controller 7 calculates the absolute value of the deviation ΔI (= I _V −I _P ) of the feedback variable (current correction value I _P ) after switching with respect to the feedback variable (current correction value I _V ) before switching. When the absolute value of the deviation ΔI is equal to or greater than a predetermined threshold value, the feedback variable gradually changes from the feedback variable before switching (current correction value I _V ) to the feedback variable after switching (current correction value I _P ). Let

In the present embodiment, when the feedback variable switching rate is α (0 <α <1), the controller 7 sets a current correction value I as a feedback variable to be changed to the following formula I = α × I _P + ( 1−α) × I _V
Calculated by

  Here, the feedback mode switching control in the present embodiment will be described along the time axis using the time charts of FIGS. The time chart of FIG. 3 shows the time history of the feedback mode flag, where the power feedback control mode flag is “1” and the voltage feedback control mode flag is “0”. The time chart of FIG. 4 shows the time history of the switching rate α. The time chart of FIG. 5 shows the time history of the feedback mode switching state, and the state in which the power feedback control mode is executed is “0”, and the state is changed from the power feedback control mode to the voltage feedback control mode. The state is represented by “1”, the state in which the voltage feedback control mode is being implemented is represented by “2”, and the state in which the voltage feedback control mode is being changed to the power feedback control mode is represented by “3”.

As shown in FIGS. 3 to 5, the controller 7 switches the feedback mode flag from “1” to “0” (when the feedback mode switching state switches from “0” to “1”). Therefore, the switching rate α is linearly decreased from ₁ , and the switching rate α is set to 0 when the time T ₁ has elapsed. At this time, the feedback mode switching state is switched from “1” to “2”. The switching rate α that decreases from 1 to 0 at the required time T ₁ is a linear function of time t as follows.
α = 1− (1 / T ₁ ) × t
In this case, the current correction value I is represented by the following linear function of time t.
_{I = I P - (I P} -I V) / T 1 × t = I P -ΔI / T 1 × t

On the other hand, the controller 7 linearly changes the switching rate α from 0 when the feedback mode flag is switched from “0” to “1” (when the feedback mode switching state is switched from “2” to “3”). The switching rate α is set to 1 when the time T ₂ has elapsed. At this time, the feedback mode switching state is switched from “3” to “0”. The switching rate α that increases from 0 to 1 in the required time T ₂ is a linear function of time t as follows.
α = (1 / T ₂ ) × t
In this case, the current correction value I is represented by the following linear function of time t.
I = I _V + (I _P −I _V ) / T ₂ × t = I _V + ΔI / T ₂ × t

In the present embodiment, the switching rate α increases when switching from the voltage feedback control mode to the power feedback control mode, rather than the decrease time T ₁ of the switching rate α when switching from the power feedback control mode to the voltage feedback control mode. The time T ₂ is set short (T ₁ > T ₂ ). In other words, in the present embodiment, when switching from the voltage feedback control mode to the power feedback control mode rather than the change rate (ΔI / T ₁ ) of the feedback variable when switching from the power feedback control mode to the voltage feedback control mode. The change rate (ΔI / T ₂ ) of the feedback variable is set large.

  In the fuel cell system 1 according to the embodiment described above, when switching from the power feedback control mode to the voltage feedback control mode (or from the voltage feedback control mode to the power feedback control mode), the feedback variable before and after switching is predetermined. Even when there is a difference greater than or equal to the threshold, the feedback variable can be gradually changed. Therefore, it is possible to suppress a rapid decrease in responsiveness due to the difference between the feedback variables before and after switching.

  That is, when the operating state of the fuel cell 2 shifts from a normal operating state to a special operating state, it can be gradually shifted from the power feedback control mode to the voltage feedback control mode. The direct current voltage does not rapidly decrease after switching the feedback mode, and the response of the output power of the fuel cell 2 to the required power does not rapidly decrease. On the other hand, when the operation state of the fuel cell 2 returns from the special operation state to the normal operation state, it can be shifted relatively quickly from the voltage feedback control mode to the original power feedback control mode. The output power can be promptly responded to the required power.

  In the present embodiment, an example in which the feedback variable (current correction value I) is linearly changed using a predetermined expression including the switching rate α as a linear function of time t has been described. However, the change mode is not limited to this. For example, the switching rate α can be changed nonlinearly with reference to a predetermined map, and the feedback variable can be changed nonlinearly accordingly.

  Moreover, in this embodiment, when controlling the operation | movement of FC converter 10, although illustrated about the controller 7 which switches and implements electric power feedback control mode and voltage feedback control mode, the following is shown to this controller 7 as follows. Additional functions can also be added.

For example, the controller 7 controls the power feedback control when the switching from the power feedback control mode to the voltage feedback control mode is completed (when the feedback mode switching state shown in FIG. 5 is switched from “1” to “2”). The feedback variable (current correction value I _P ) in the mode can be initialized (set to a predetermined initial value). Similarly, the controller 7 performs voltage feedback when the switching from the voltage feedback control mode to the power feedback control mode is completed (when the feedback mode switching state shown in FIG. 5 is switched from “3” to “0”). A feedback variable (current correction value I _V ) in the control mode can be initialized (set to a predetermined initial value). In this way, it is possible to suppress a decrease in responsiveness due to accumulation of correction terms.

Further, the controller 7 has a current correction value (I _P or I _V ) or duty command value (D) as a feedback variable calculated in each feedback control mode exceeding a predetermined upper limit value (or lower than a predetermined lower limit value). ), The integral feedback gain in each feedback control mode can be set to zero (accumulation of integral terms can be stopped). If it does in this way, a fall of responsiveness can be controlled more effectively.

  In addition, when the number of drive phases of the FC converter 10 changes according to the required power, the controller 7 can also change the upper limit value and the lower limit value of the feedback variable (current correction value) according to the number of drive phases.

  In the above embodiment, an example in which the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been shown. However, various mobile bodies (robots, ships, aircrafts, etc.) other than the fuel cell vehicle are related to the present invention. A fuel cell system can also be installed. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.). Furthermore, the present invention can be applied to a portable fuel cell system.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 5 ... Traction motor (load apparatus), 7 ... Controller (control means), 10 ... FC converter.

Claims (8)

A fuel cell system comprising a converter provided between a fuel cell and a load device, and control means for controlling the operation of the converter,
The control means includes a power feedback control mode for controlling the operation of the converter based on the output power of the fuel cell, and a voltage feedback control mode for controlling the operation of the converter based on the output voltage of the fuel cell. When the feedback variable before and after switching has a difference equal to or greater than a predetermined threshold, the feedback variable is gradually changed from the feedback variable before switching to the feedback variable after switching.
Fuel cell system. The control means includes a change rate of a feedback variable when switching from the power feedback control mode to the voltage feedback control mode, and a change rate of a feedback variable when switching from the voltage feedback control mode to the power feedback control mode. , Which is different
The fuel cell system according to claim 1. The control means has a feedback variable change speed when switching from the voltage feedback control mode to the power feedback control mode, rather than a feedback variable change speed when switching from the power feedback control mode to the voltage feedback control mode. Is a large setting,
The fuel cell system according to claim 2. The control means sets a feedback variable in the power feedback control mode as a current correction value I _P , a feedback variable in the voltage feedback control mode as a current correction value I _V , and a switching rate α (0 <α <1). In this case, the current correction value I as a feedback variable to be changed is expressed by the following formula: I = α × I _P + (1−α) × I _V
Is calculated by
The fuel cell system according to any one of claims 1 to 3. The control means initializes a feedback variable in the power feedback control mode when the switching from the power feedback control mode to the voltage feedback control mode is completed.
The fuel cell system according to any one of claims 1 to 4. The control means initializes a feedback variable in the voltage feedback control mode when switching from the voltage feedback control mode to the power feedback control mode is completed.
The fuel cell system according to any one of claims 1 to 5. The control means adopts an integral feedback gain when calculating a feedback variable in each feedback control mode, and sets the integral feedback gain to zero when the calculated feedback variable exceeds a predetermined upper limit value. To do,
The fuel cell system according to any one of claims 1 to 6. The control means employs an integral feedback gain when calculating a feedback variable in each feedback control mode, and sets the integral feedback gain to zero when the calculated feedback variable is below a predetermined lower limit value. To do,
The fuel cell system according to any one of claims 1 to 7.

Images