JP2013169076A - Operation method of moving body and moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend a running distance of a fuel cell vehicle when a short circuit fault is caused in a first converter that regulates output voltage of a fuel cell.SOLUTION: There is provided an operation method of a fuel cell vehicle 1 that has a first converter 30 that is connected between a fuel cell 20 and a traction motor 60 and steps-up and steps-down an output voltage of the fuel cell 20; and a second converter 50 that is connected between a secondary battery 40 and the traction motor 60 and steps-up and steps-down the voltage of the secondary battery 40. This operation method causes power supply from the fuel cell 20 to the traction motor 60 to be continued, when a circuit of a first converter 30 shorts and break down, and when prescribed conditions are satisfied: (1) fuel cell output voltage V1≥ traction motor required voltage V2, (2) fuel cell output voltage V1≥ secondary cell output voltage V3+α (α is a positive constant).

Description

  The present invention relates to a driving method of a moving body and a moving body.

  Some so-called fuel cell vehicles include a hybrid type that uses a fuel cell and a secondary battery in combination as a power source.

  This type of fuel cell vehicle is disposed between the fuel cell and the traction motor, and is disposed between the FC converter that raises and lowers the output voltage of the fuel cell, and between the secondary battery and the traction motor. Some employ a two-converter system having a BT converter that steps up and down the output voltage (see Patent Document 1).

  In such a fuel cell vehicle, during normal operation, the output voltage of the fuel cell is boosted by the FC converter and supplied to the traction motor. The BT converter steps down the voltage of the regenerative operation of the traction motor to charge the secondary battery, or steps up the output voltage of the secondary battery and supplies it to the traction motor.

  By the way, a short circuit abnormality may occur in the FC converter, such as a short circuit of an output diode in the circuit of the FC converter during operation. In this case, conventionally, the power generation of the fuel cell is stopped immediately and power is supplied from the secondary battery to the traction motor.

JP 2007-209161 A

  However, since the capacity of the secondary battery is generally small, the vehicle cannot travel a sufficient distance only with the power of the secondary battery.

  The present invention has been made in view of this point, and an object thereof is to extend the travel distance of a moving body such as a fuel cell vehicle when a short circuit abnormality occurs in the converter.

To achieve the above object, the present invention is connected between a fuel cell and a load, and is connected between a secondary converter and a load, a first converter that steps up and down the output voltage of the fuel cell, and a secondary battery. A method of operating a moving body having a second converter for stepping up and down the voltage of a battery, and when a short circuit failure occurs in the circuit of the first converter, a predetermined condition is satisfied. Output voltage V1 of fuel cell ≥ Required voltage V2 of load (1)
Fuel cell output voltage V1 ≧ secondary battery output voltage V3 + α (2)
(Α is a positive constant)
In the case of satisfying the above, it is a method for operating the moving body in which the supply of power from the fuel cell to the load is continued.

  According to the present invention, even when the circuit of the first converter is short-circuited, the predetermined conditions (1) and (2) that enable the supply and control of power from the fuel cell to the load are satisfied. In addition, since the supply of power from the fuel cell to the load is continued, the travel distance of the mobile body can be extended.

  In the operation method of the moving body, it is determined whether or not the predetermined condition is satisfied, and when the predetermined condition is satisfied, the supply of electric power from the fuel cell to the load is continued, and the predetermined condition is satisfied. If the above condition is not satisfied, the supply of power from the fuel cell to the load may be stopped and the supply of power from the secondary battery to the load may be started.

  When the predetermined condition is satisfied and the supply of power from the fuel cell to the load is continued, the second converter may control the input voltage to the load.

According to another aspect of the present invention, there is provided a first converter that is connected between a fuel cell and a load and that steps up and down an output voltage of the fuel cell, and is connected between the secondary battery and the load. And a second converter that raises and lowers the voltage of the first converter when a short circuit failure occurs in the circuit of the first converter. Predetermined conditions: Output voltage V1 of fuel cell ≧ Required voltage V2 of load
Fuel cell output voltage V1 ≧ secondary battery output voltage V3 + α (2)
(Α is a positive constant)
In the case of satisfying the condition, the moving body has means for continuing the supply of electric power from the fuel cell to the load.

  The moving body continues to supply power from the fuel cell to the load when the predetermined condition is satisfied, and the means for determining whether or not the predetermined condition is satisfied, and satisfies the predetermined condition. In the case of not satisfying the condition, there may be provided means for stopping the supply of power from the fuel cell to the load and starting the supply of power from the secondary battery to the load.

  In the mobile body, when the predetermined condition is satisfied and the supply of power from the fuel cell to the load is continued, the second converter may control the input voltage to the load.

  ADVANTAGE OF THE INVENTION According to this invention, the travel distance of a moving body when a short circuit abnormality arises in the 1st converter which raises / lowers the output voltage of a fuel cell can be extended.

It is a block diagram which shows the structure of the electric power system of a fuel cell vehicle. It is explanatory drawing which shows the outline of the circuit structure of a 1st converter. It is a flowchart which shows an example of the driving | running method of a fuel cell vehicle.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows functional blocks of a power system of a fuel cell vehicle 1 as a moving body according to the present embodiment.

  The fuel cell vehicle 1 is, for example, a fuel cell (FC) 20 that generates power by an electrochemical reaction between an oxidizing gas and a fuel gas, and a DC / DC converter that steps up and down the output voltage of the power generated by the fuel cell 20. A first converter (FDC) 30, a secondary battery (BATT) 40 serving as an auxiliary power source that can be charged and discharged, and a second converter (BDC) that is a DC / DC converter that steps up and down the output voltage of the secondary battery 40. 50, a traction inverter (INV) 70 that converts DC power into AC power (for example, three-phase AC) and supplies power to a traction motor (M) 60 that is a load, and controls the operation of each part of the fuel cell vehicle 1 A control unit (ECU) 80 is provided.

  The fuel cell 20 is, for example, a polymer electrolyte fuel cell, and has a stack structure in which a large number of single cells are stacked. The single cell includes an air electrode formed on one surface of an electrolyte membrane made of an ion exchange membrane, a fuel electrode formed on the other surface of the electrolyte membrane, and a pair of separators that sandwich the air electrode and the fuel electrode from both sides. Have

  The first converter 30 is a direct-current voltage converter for a fuel cell, and can raise and lower the output voltage of the fuel cell 20 to a predetermined direct-current voltage and supply it to the traction inverter 70. The first converter 30 includes a voltage sensor 31 that detects the output voltage V1 of the fuel cell 20. The first converter 30 has, for example, four phases of a U phase, a V phase, a W phase, and an X phase, and operates by changing the number of drive phases according to the passing power.

  FIG. 2 shows an outline of the chopper type voltage change circuit of the first converter 30. As a circuit of each phase, the first converter 30 includes a transistor Tr as a switching element that periodically turns on and off according to a carrier frequency, a reactor L, a smoothing capacitor C, and an output diode as a rectifying element. D etc. are provided.

When the transistor Tr is turned on, the energy supplied from the fuel cell 20 is accumulated in the reactor L, and the accumulated energy is transferred to the smoothing capacitor C via the diode D when the transistor Tr is turned off. By this process is repeated, it is possible to energy stored in the smoothing capacitor C is increased, to boost the output voltage V1 of the fuel cell 20 to the target voltage V _H.

  The secondary battery 40 shown in FIG. 1 is a power storage device that functions as a surplus power storage source, a regenerative energy storage source during regenerative braking, and an energy buffer during load fluctuations associated with acceleration or deceleration of the fuel cell vehicle 1. Secondary batteries (nickel / cadmium storage batteries, nickel / hydrogen storage batteries, lithium secondary batteries, etc.) are suitable.

  The second converter 50 is connected in parallel between the first converter 30 and the traction inverter 70. The second converter 50 can charge the secondary battery 40 by reducing the surplus power of the fuel cell 20 or the regenerative power collected by the traction motor 60. The second converter 50 can boost the output voltage V3 of the secondary battery 40 to a predetermined DC voltage and supply the boosted voltage to the traction inverter 70. The second converter 50 includes a voltage sensor 51 that detects the voltage on the output side of the first converter 30 (the input side of the traction inverter 70). The second converter 50 can control the input voltage of the traction inverter 70 (traction motor 60) when the first converter 30 is stopped.

  The traction inverter 70 can control the rotational torque of the traction motor 60 by converting DC power supplied from either or both of the fuel cell 20 and the battery 40 into AC power (for example, three-phase AC). The traction motor 60 is, for example, a three-phase AC motor connected to wheels, and generates a driving propulsion force when the vehicle travels, and functions as a motor generator when the vehicle brakes, and converts kinetic energy into electric energy to regenerate electric power. Can be recovered.

  The control unit 80 is a so-called microcomputer and includes a CPU, a ROM, a RAM, an input / output interface, and the like. The control unit 80 includes a fuel cell 20, a first converter 30, a secondary battery 40, a second converter 50, a traction inverter 70, and various sensors such as voltage sensors 31 and 51 and a rotation speed sensor provided in the motor 16. And an accelerator pedal sensor. The control unit 80 controls the operation of the fuel cell vehicle 1 by controlling these operations.

  Next, a driving method of the fuel cell vehicle 1 configured as described above will be described. FIG. 3 shows a flowchart of such an operation method.

  During operation of the fuel cell vehicle 1, the target power generation amount of the fuel cell 10, the required voltage V2 of the traction motor 60, etc., based on values detected by the control unit 80 by various sensors such as an accelerator pedal sensor of the traction motor 16, for example. Is determined.

  During normal operation, the fuel cell 20 is operated by a command from the control unit 80, and the output voltage V1 of the electric power generated in the fuel cell 20 is boosted to the required voltage V2 of the traction motor 60 by, for example, the first converter 30. And added to the traction inverter 70. The traction inverter 70 converts the AC power into AC power, and the traction motor 60 is driven. In the secondary battery 40, for example, surplus power of the fuel cell 20 and regenerative power recovered by the traction motor 60 are raised and lowered by the second converter 50 and stored.

For example, when the output diode D of the circuit of the first converter 30 has a short circuit abnormality, it is first determined whether or not the operation of the fuel cell 20 is continued (S1 in FIG. 3). This is determined based on whether or not a predetermined condition that enables power supply from the fuel cell 20 to the traction motor 60 even if the first converter 30 is stopped is satisfied (S2 in FIG. 3). More specifically, it is determined by whether or not the predetermined conditions (1) and (2) are satisfied.
Output voltage V1 of the fuel cell ≧ Required voltage V2 of the traction motor (1)
Fuel cell output voltage V1 ≧ secondary battery output voltage V3 + α (2)
(Α is a positive constant)

  Here, conditions (1) and (2) will be described.

  When the first converter 30 is stopped due to a short-circuit failure and the fuel cell 20 and the traction inverter 70 (traction motor 60) are directly connected, the output voltage V1 of the fuel cell 20 is directly input to the traction inverter 70, that is, the traction. The required voltage V2 of the motor 60 can be obtained. Therefore, the condition (1) requires that the output voltage V1 of the fuel cell 20 is not higher than the required voltage V2 of the traction motor 60 and does not need to be boosted by the first converter 30.

  Further, when the first converter 30 is stopped and is in a directly connected state, if the output voltage V3 of the secondary battery 40 is higher than the output voltage V1 of the fuel cell 20, the input voltage of the traction inverter 70 is output by the second converter 50. Can no longer be controlled. Therefore, the condition (2) requires that the output voltage V1 of the fuel cell 20 is higher than the output voltage V3 of the secondary battery 40.

  Further, a positive constant α is added to the output voltage V3 of the secondary battery 40 as the operation guarantee voltage difference of the second converter 50. For example, when the first converter 30 is in operation, the output voltage V1 of the fuel cell 20 is detected by the voltage sensor 31 to control the input voltage of the traction inverter 70, but when the first converter 30 stops, The output voltage V1 of the fuel cell 20 needs to be detected by the voltage sensor 51 to control the input voltage of the traction inverter 70. As described above, since the sensor is changed, α is added to the condition (2) in consideration of a measurement error caused by an individual difference of the sensor. For example, the value of α is preferably about 30 to 50 V, more preferably about 40 V.

  As shown in FIG. 3, when the predetermined conditions (1) and (2) are satisfied, the operation of the fuel cell 20 is continued, and the supply of electric power from the fuel cell 20 to the traction motor 60 is continued (FIG. 3). S3). At this time, the input voltage of the traction inverter 70 (traction motor 60) is controlled by the second converter 50. Thus, the travel of the fuel cell vehicle 1 by the power generation of the fuel cell 20 is continued.

  When the predetermined conditions (1) and (2) are not satisfied, the operation of the fuel cell 20 is stopped, and the supply of power from the fuel cell 20 to the traction motor 60 is stopped. In addition, power is supplied from the secondary battery 40 to the traction motor 60 through the second converter 50 (S4 in FIG. 3). Thereby, the travel of the fuel cell vehicle 1 by the secondary battery 40 is continued.

  According to the present embodiment, even when the circuit of the first converter 30 is short-circuited, the predetermined condition (1) that enables supply and control of power from the fuel cell 20 to the traction motor 60 and When the condition (2) is satisfied, the supply of electric power from the fuel cell 20 to the traction motor 60 is continued, so that the travel distance of the fuel cell vehicle 1 can be extended.

  Since the second converter 50 controls the input voltage to the traction motor 60 when the predetermined conditions (1) and (2) are satisfied, the fuel cell vehicle using the fuel cell 20 when the first converter 30 fails. 1 traveling can be appropriately realized.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  For example, the short-circuit fault of the first converter 30 includes not only a short-circuit fault of the diode D but also a short-circuit fault of the capacitor C. In addition to the fuel cell vehicle 1 described in the above embodiment, the present invention can be applied to various moving bodies such as ships, airplanes, and robots. It can also be applied to a stationary power source or the like.

  The present invention is useful for extending the travel distance of a moving object when a short circuit failure occurs in the first converter that adjusts the output voltage of the fuel cell.

DESCRIPTION OF SYMBOLS 1 Fuel cell vehicle 20 Fuel cell 30 1st converter 40 Secondary battery 50 2nd converter 60 Traction motor 70 Traction inverter 80 Control unit

Claims (6)

A first converter connected between the fuel cell and the load for increasing / decreasing the output voltage of the fuel cell; and a second converter connected between the secondary cell and the load for increasing / decreasing the voltage of the secondary battery; A method of driving a mobile object having
When the first converter circuit is short-circuited, the predetermined condition is: Fuel cell output voltage V1 ≧ Load required voltage V2 (1)
Fuel cell output voltage V1 ≧ secondary battery output voltage V3 + α (2)
(Α is a positive constant)
A driving method for a moving body, in which the supply of electric power from the fuel cell to the load is continued when the above condition is satisfied.   It is determined whether or not the predetermined condition is satisfied, and when the predetermined condition is satisfied, the supply of electric power from the fuel cell to the load is continued, and when the predetermined condition is not satisfied, the fuel is The method for operating a moving body according to claim 1, wherein supply of electric power from the battery to the load is stopped and supply of electric power from the secondary battery to the load is started.   3. The mobile body according to claim 1, wherein the second converter controls an input voltage to the load when the predetermined condition is satisfied and supply of electric power from the fuel cell to the load is continued. how to drive. A first converter connected between the fuel cell and the load for increasing / decreasing the output voltage of the fuel cell; and a second converter connected between the secondary cell and the load for increasing / decreasing the voltage of the secondary battery; A moving body having
When the first converter circuit is short-circuited, the predetermined condition is: Fuel cell output voltage V1 ≧ Load required voltage V2 (1)
Fuel cell output voltage V1 ≧ secondary battery output voltage V3 + α (2)
(Α is a positive constant)
A mobile body having means for continuing the supply of electric power from the fuel cell to the load when the fuel cell is satisfied. Means for determining whether or not the predetermined condition is satisfied;
When the predetermined condition is satisfied, the supply of power from the fuel cell to the load is continued, and when the predetermined condition is not satisfied, the supply of power from the fuel cell to the load is stopped, and the secondary The moving body according to claim 4, further comprising means for starting supply of electric power from the battery to the load.   The moving body according to claim 4 or 5, wherein the second converter controls an input voltage to the load when the predetermined condition is satisfied and the supply of electric power from the fuel cell to the load is continued.

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