JP4746593B2 - Contactor connection / disconnection method - Google Patents

Description

  The present invention relates to a method for connecting / disconnecting a contactor having no precharge circuit.

For example, in a fuel cell vehicle, a secondary battery is provided as an auxiliary power source together with the fuel cell, and the electrical connection is cut off between the traveling motor and the fuel cell, and between the traveling motor and the secondary battery, respectively. Contactors are provided. In this type of fuel cell vehicle, in order to prevent an inrush current when supplying power to the traveling motor, the contactor on the secondary battery side is turned on, and the fuel after the voltage on the secondary battery side exceeds a predetermined value A technique for turning on a battery-side contactor has been proposed (see Patent Document 1).
JP 2004-166376 A (FIGS. 1 and 2)

  However, with the contactor connection method described in Patent Document 1, the inrush current at the time of connection can be kept low, but it is difficult to completely eliminate the inrush current.

  Further, in a high voltage circuit including a contactor having no precharge circuit as in Patent Document 1, a connection signal has been simultaneously output to the P-side and N-side switches. However, since there is a variation in the product from when the connection signal is issued until the switch is actually connected, it has not been possible to control whether the inrush current flows on the P side or the N side. For this reason, an inrush current flows through one switch every time, and the performance of only one switch may be reduced.

  Similarly, when the contactor is shut off, there is a variation on the product in the time until the contactor is actually shut down, so it is possible to control which of the P-side and N-side switches generates arc discharge. In other words, an arc discharge is generated every time one of the switches, and the performance of only one of the switches may be deteriorated.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a contactor connection / disconnection method capable of providing sufficient durability against contactor connection / disconnection.

According to a first aspect of the present invention, there is provided a fuel cell, a load that receives power supply from the fuel cell, and an electromagnetic open / close switch that disconnects connection between a positive electrode and a negative electrode on a power line that connects the fuel cell and the load. A fuel cell contactor having no precharge circuit, connected to the load in parallel with the fuel cell, supplying power to the load, and charging power generated by the fuel cell A high voltage battery, a DC / DC converter that boosts the voltage from the high voltage battery when the fuel cell system is started up, and a positive electrode and a negative electrode on a power line connecting the high voltage battery and the DC / DC converter, respectively. A battery contactor having a switch and a precharge circuit; and the DC / DC converter and the battery contactor. A contactor connection / disconnection method in a fuel cell system comprising: a capacitor connected to the battery contactor, wherein at the time of startup of the fuel cell system, one of the battery contactors on the side where the precharge circuit is not provided Connect the switch and connect the precharge circuit to start charging the capacitor, and when the charging of the capacitor is completed, disconnect the precharge circuit after connecting the other switch of the battery contactor, When the voltage on the fuel cell side of the fuel cell contactor becomes substantially equal to the voltage on the DC / DC converter side of the fuel cell contactor, a connection signal of the fuel cell contactor is output, and the fuel cell when issuing the connection signal for connecting the use contactors, before and the positive electrode side switch Connected to the other of the two switches when the first predetermined time required to securely connect the one of the switches the has passed since issuing a connection signal to one of two switches as the timing for connecting the negative electrode side switch causing deviation by outputting a signal at every predetermined number of times the connection signal is issued, in reverse order for connecting the between the positive electrode side switch the negative electrode side switch, when stopping the fuel cell system, the fuel When a shut-off signal for shutting off a battery contactor is issued, a shut-off signal is issued to one of the two switches as a timing for shutting off the positive switch and the negative switch, and then the one switch is securely shut off. When the second predetermined time required for elapses, a cutoff signal is output to the other of the two switches to cause a shift, and the cutoff signal is issued. The order of shutting off the positive side switch and the negative side switch is switched every predetermined number of times, and the voltage on the fuel cell side of the fuel cell contactor scavenges the inside of the fuel cell, so that the fuel cell contactor When the voltage on the DC / DC converter side between one of the two switches of the two switches is reduced to a predetermined value at which the voltage gradually decreases, the cutoff signal of the fuel cell contactor is output, The order of connecting the positive side switch and the negative side switch when the connection signal is issued, and the order of cutting off the positive side switch and the negative side switch when the cutoff signal is issued Are equal to each other.
The first predetermined time corresponds to [t1-t2] in FIG. 3 described in an embodiment described later. The second predetermined time corresponds to [t4-t5] in FIG. 3 described in an embodiment described later.

  According to the first aspect of the present invention, the order of connecting the positive side and negative side switches is changed every predetermined number of times, and the positive side and negative side switches are equally charged with inrush current. Therefore, the durability of the contactor as a whole can be increased.

According to the first aspect of the present invention, even when shutting off, the order of shutting off the switches on the positive electrode side and the negative electrode side is changed every predetermined number of times, and arc discharge is equally performed on each switch on the positive electrode side and the negative electrode side Therefore, the durability of the contactor as a whole can be increased.

According to the invention which concerns on Claim 1 , a charge can be shared more equally by making connection and interruption | blocking into the same order. By the way, the degree of load of the inrush current is different from that of arc discharge, and the load is larger with the inrush current.

  According to the contactor connection / cutoff method of the present invention, it is possible to provide sufficient durability against contactor connection / cutoff.

  FIG. 1 is an overall configuration diagram showing a fuel cell vehicle to which the contactor connection / cutoff method of this embodiment is applied. In the present embodiment, the case where the present invention is applied to the fuel cell vehicle V will be described as an example. However, the present invention is not limited to this, and may be applied to an electric vehicle, a hybrid vehicle, a ship, an aircraft, and the like.

  As shown in FIG. 1, a fuel cell vehicle V includes a fuel cell stack (power source) 10, a travel motor (load) 20, a motor PDU (Power Drive Unit) 30, a fuel cell contactor 40, a high voltage secondary battery 50, An ECU (Electric Control Unit) 60 is provided.

  The fuel cell stack (FC stack) 10 is a membrane electrode formed by sandwiching one side of an electrolyte membrane made of a solid polymer having proton conductivity with an anode (hydrogen electrode) and the other side with a cathode (air electrode). The membrane electrode assembly has a structure in which a plurality of unit cells each having a membrane electrode assembly sandwiched between conductive separators are stacked. In this fuel cell stack 10, hydrogen is supplied from a hydrogen tank (not shown) to the anode, and an air compressor (not shown) is driven to supply air (oxygen) to the cathode. Proton) permeates through the electrolyte membrane toward the anode, and electrons move to the cathode via the traveling motor 20 (load) or the like to generate power. At the cathode, the permeated hydrogen ions, oxygen and electrons in the air Produces water. In addition, the water produced | generated by electric power generation is discharged | emitted out of a vehicle, for example.

  The travel motor 20 is composed of, for example, a permanent magnet type three-phase AC synchronous motor, and rotationally drives drive wheels provided in the fuel cell vehicle V by electric power supplied from the fuel cell stack 10 and the high voltage secondary battery 50. . The traveling motor 20 is connected to the fuel cell stack 10 via a motor PDU (Power Drive Unit) 30.

  The motor PDU 30 is configured by an inverter circuit or the like, and has a function of converting direct current power from the fuel cell stack 10 or a high voltage secondary battery 50 described later to alternating current power and supplying the alternating current power to the traveling motor 20. Yes. The motor PDU 30 also has a function of charging the high-voltage secondary battery 50 by converting the regenerative power of the traveling motor 20 into DC power.

  The fuel cell contactor 40 does not have a precharge circuit, and is provided on power lines L1 and L2 connecting the fuel cell stack 10 and the motor PDU 30. That is, a switch (electromagnetic switch) 41 on the positive side of the contactor 40 for fuel cell that performs connection / cutoff is provided on the power line L1 that connects the positive electrode of the fuel cell stack 10 and the positive electrode of the motor PDU 30. Further, a switch (electromagnetic switch) 42 on the negative electrode side of the contactor 40 for fuel cell that connects and disconnects is provided on the power line L2 that connects the negative electrode of the fuel cell stack 10 and the negative electrode of the motor PDU 30.

  The high-voltage secondary battery 50 is connected in parallel to the fuel cell stack 1 and is connected to the traveling motor 20 via the motor PDU 30. The high-voltage secondary battery 50 is, for example, a lithium ion battery, a nickel hydride battery, or the like, and can be charged and discharged while receiving power generated from the fuel cell stack 1.

  The high-voltage secondary battery 50 is connected via power lines L1 and L2 that connect the fuel cell stack 10 and the motor PDU 30 and power lines L3 and L4. More specifically, the power lines L3 and L4 are connected downstream of the fuel cell contactor 40, that is, between the motor PDU 30 and the fuel cell contactor 40, the power line L3 is connected to the power line L1, and the power line L4 is connected to the power line L2. Connected with.

  A battery contactor 51 and a DC / DC converter 56 are provided on the power lines L3 and L4. The battery contactor 51 is provided with a positive switch (electromagnetic switch) 52 on the power line L3 and a negative switch (electromagnetic switch) 53 on the power line L4. Further, the battery contactor 51 is provided with a precharge circuit 54 together with the switch 52.

  The precharge circuit 54 includes an electric wire 54a, a resistor 54b, and a spare switch 54c including an electromagnetic switch. Both ends of the electric wire 54a are connected to the upstream side and the downstream side of the switch 52, respectively, and a resistor 54b and a spare switch 54c are provided in series on the electric wire 54a.

  The DC / DC converter 56 has a function of converting a DC voltage into another DC voltage, and is provided on the power lines L3 and L4 on the downstream side of the battery contactor 51.

  A capacitor 57 is provided on the power lines L3 and L4 between the battery contactor 51 and the DC / DC converter 56 so as to connect the power line L3 and the power line L4.

  The ECU 60 includes a CPU (Central Processing Unit), a memory, a program, and the like, and appropriately controls opening and closing of the switches 41 and 42 of the fuel cell contactor 40, the switches 52 and 53 of the battery contactor 51, and the standby switch 54c. Further, the ECU 60 receives, for example, a voltage value V1 from the voltage sensor 61 provided on the upstream side (fuel cell stack 1 side) of the fuel cell contactor 40, and a voltage sensor 62 provided on the downstream side of the fuel cell contactor 40. Each voltage value V2 is acquired.

(First embodiment)
Next, a contactor connection / cutoff method according to the first embodiment will be described with reference to FIGS. 2 and 3 for a connection method of a fuel cell contactor (hereinafter abbreviated as a contactor) 40. FIG. 2 is a flowchart showing a contactor connection / disconnection method according to the first embodiment, and FIG. 3 is a timing chart according to the first embodiment. In the first embodiment, when a connection signal for connecting the contactor 40 is issued, the timing for connecting the positive switch 41 and the timing for connecting the negative switch 42 are shifted, and the connection signal is output. The order of connecting the positive switch 41 and the negative switch 42 is switched every predetermined number of times. When the operation of the fuel cell vehicle V is stopped, the positive switch 41 and the negative switch 42 of the contactor 40 are cut off (off). Similarly, the switches 52 and 53 and the spare switch 54c of the battery contactor 51 are also cut off (off).

  First, when an ignition switch (not shown) of the fuel cell vehicle V is turned on by the driver, the ECU 60 outputs a connection signal for connecting the contactor 40 and at the same time the switch (negative electrode side) 53 of the battery contactor 51. Is connected (ON), the spare switch 54c of the precharge circuit 54 is connected (ON), and charging of the capacitor 57 is started. At this time, the flow of the inrush current is restricted by the resistor 54b provided in the precharge circuit 54. When the capacitor 57 is charged, the switch (positive electrode side) 52 is connected (ON). Then, the spare switch 54c is shut off (OFF).

  Further, the ECU 60 uses the electric power stored in the high-voltage secondary battery 50 to open, for example, a hydrogen tank shut-off valve and drive an air compressor to supply hydrogen and air to the fuel cell stack 10. The voltage (open end voltage) of the fuel cell stack 10 is increased to a predetermined value. The predetermined value means a voltage value at which power can be supplied from the fuel cell stack 10.

  In step S101, the ECU 60 determines whether or not the contactor 40 may be connected. The connection condition at this time is that the voltage V2 on the downstream side of the contactor 40 after being supplied from the high-voltage secondary battery 50 and converted in voltage by the DC / DC converter 56 is the voltage V1 on the upstream side of the contactor 40. It can be judged by whether or not. In step S101, when the ECU 60 determines that the voltage V2 on the downstream side of the contactor 40 is not substantially equal to the voltage V1 on the upstream side (No), the ECU 60 repeats step S101 and performs the voltage V2 on the downstream side of the contactor 40. Is determined to be substantially equal to the upstream voltage V1 (Yes), the process proceeds to step S102.

  In step S102, the ECU 60 determines whether or not the order determination flag is “0”. Note that the order determination flag is, for example, “0” or “1”, and one of the flags is stored in the memory, appropriately read, and rewritten. If the ECU 60 determines in step S102 that the read order determination flag is “0” (Yes), the process proceeds to step S103.

  In step S <b> 103, the ECU 60 outputs an ON command for connecting the negative side (N side) switch 42 of the contactor 40 to make the power line L <b> 2 connecting the fuel cell stack 10 and the motor PDU 30 conductive.

  In step S104, the ECU 60 determines whether a predetermined time has elapsed since the ON command was issued in step S103. The predetermined time here is a time required for the negative switch 42 to be securely connected, and is determined by a timer (not shown) provided in the ECU 60, for example. In step S104, when it is determined that the predetermined time has not elapsed (No), the ECU 60 repeats the process of step S104. When it is determined that the predetermined time has elapsed (Yes), the ECU 60 proceeds to step S105. .

  In step S105, the ECU 60 outputs an ON command for connecting the positive electrode side (P side) switch 41 of the contactor 40 to make the power line L1 connecting the fuel cell stack 10 and the motor PDU 30 conductive.

  In step S106, the ECU 60 determines whether or not a predetermined time has elapsed since the ON command was issued in step S105. Note that the predetermined time here is also a time necessary for the positive-side switch 41 to be reliably connected, as described above, and is determined by, for example, a timer (not shown). In step S106, when it is determined that the predetermined time has not elapsed (No), the ECU 60 repeats the process of step S106, and when it is determined that the predetermined time has elapsed (Yes), the process proceeds to step S107. .

  In step S107, the ECU 60 rewrites the order determination flag “0” stored in the memory to “1”, and ends the connection of the contactor 40. When the connection of the contactor 40 is completed, the generated power of the fuel cell stack 10 can be supplied to the traveling motor 20 and the like. Further, the power supply from the high-voltage secondary battery 50 is switched to the power supply to the fuel cell stack 10 to drive an air compressor or the like.

  When the ignition switch is turned off by the driver and a connection signal for connecting the contactor 40 is output next time, in step S102 of the flow in FIG. 2, the ECU 60 determines that the order determination flag stored in the memory is “ 1 "and the process proceeds to step S108.

  In step S108, contrary to the previous time, the ECU 60 first outputs an ON command for connecting the positive side (P side) switch 41 of the contactor 40 to conduct the power line L1 connecting the fuel cell stack 10 and the motor PDU 30. Let

  Then, the process proceeds to step S109, and the ECU 60 determines whether or not the predetermined time has elapsed in the same manner as in step S106. If it is determined that the predetermined time has not elapsed (No), the process of step S109 is performed. If it is determined repeatedly that the predetermined time has elapsed (Yes), the process proceeds to step S110.

  In step S110, the ECU 60 outputs an ON command for connecting the negative side (N side) switch 42 of the contactor 40, and makes the power line L2 connecting the fuel cell stack 10 and the motor PDU 30 conductive.

  And it progresses to step S111 and ECU60 judges whether predetermined time passed like step S104, and when it is judged that predetermined time has not passed (No), processing of step S111 is performed. If it is determined repeatedly that the predetermined time has elapsed (Yes), the process proceeds to step S112.

  In step S112, the ECU 60 rewrites the order determination flag “1” stored in the memory to “0”, and ends the connection of the contactor 40.

  And when connecting the contactor 40 next time, the process of step S101-S107 is performed.

  Further, referring to the time chart of FIG. 3, in the first connection of the contactor 40, as shown in FIG. 3A, the voltage V2 on the downstream side of the contactor 40 becomes the voltage on the upstream side at the time t1. When it becomes substantially equal to V1 (S101, Yes), an ON command is issued to the switch 42 on the negative electrode side of the contactor 40 (S103). When a predetermined time (t2-t1) has elapsed from the ON command (S104, Yes), an ON command is issued to the positive switch 41 (time t2, S105). At this time, an inrush current flows through the switch 41 on the positive electrode side, and the voltage V2 on the downstream side of the contactor 40 becomes equal to the voltage V1 on the upstream side. Then, when a predetermined time (t3-t2) has elapsed from the ON command to the positive switch 41 (S106, Yes), the order determination flag “0” is rewritten to “1” (time t3, S107).

  In the next (second) contactor 40 connection, as shown in FIG. 3B, when the voltage V2 on the downstream side of the contactor 40 becomes substantially equal to the voltage V1 on the upstream side at time t1 (S101, Yes). ), An ON command is issued to the switch 41 on the positive side of the contactor 40 (S108). When a predetermined time (t2-t1) elapses from the ON command (S109, Yes), an ON command is issued to the negative switch 42 (time t2, S110). At this time, an inrush current flows through the switch 42 on the negative electrode side, and the voltage V2 on the downstream side of the contactor 40 becomes equal to the voltage V1 on the upstream side. When a predetermined time (t3-t2) has elapsed from the ON command to the negative switch 42 (S111, Yes), the order determination flag “1” is rewritten to “0” (time t3, S112).

  According to the present embodiment, the timing for connecting the positive switch 41 and the timing for connecting the negative switch 42 of the contactor 40 are shifted from each other, and each connection is performed once (every predetermined number of times). Change the order. As a result, the positive side switch 41 and the negative side switch 42 can be provided with an inrush current alternately (evenly), so that the durability of the contactor 40 can be increased.

(Second Embodiment)
FIG. 4 is a flowchart showing a contactor connection / disconnection method according to the second embodiment, and FIG. 5 is a timing chart according to the second embodiment. In the second embodiment, when a shut-off signal for shutting off the contactor 40 is issued, the timing for shutting off the positive-side switch 41 and the negative-side switch 42 is shifted, and every predetermined number of times the shut-off signal is issued. Further, the order of shutting off the positive switch 41 and the negative switch 42 is switched.

  For example, when the ignition switch is turned off by the driver, the ECU 60 outputs a shut-off signal that shuts off the contactor 40, and determines in step S201 whether or not the contactor 40 may be shut off. In this case, in the case of the fuel cell vehicle V, the shut-off condition at this time is whether the fuel cell stack 10 has been scavenged with scavenging gas (such as air), and the voltage of the fuel cell stack 10 has decreased to a predetermined value. It can be judged by how. In step S201, when the ECU 60 determines that the voltage (V1, V2) of the fuel cell stack 10 has not decreased to a predetermined value (No), the ECU 60 repeats step S201, and the voltage of the fuel cell stack 10 reaches a predetermined value. If it is determined that the value has decreased (Yes), the process proceeds to step S202.

  In step S202, the ECU 60 determines whether or not the order determination flag is zero. Note that the order determination flag is, for example, “0” or “1”, and one of the flags is stored in the memory, appropriately read, and rewritten. In step S202, when the ECU 60 determines that the read order determination flag is “0” (Yes), the process proceeds to step S203.

  In step S203, the ECU 60 outputs an OFF command for shutting off the negative side (N side) switch 42 of the contactor 40, and shuts off the power line L2 that connects the fuel cell stack 10 and the motor PDU 30.

  In step S204, the ECU 60 determines whether or not a predetermined time has elapsed since the OFF command was issued in step S103. Here, the predetermined time is a time required for the negative switch 42 to be reliably cut off, and is determined by a timer (not shown) provided in the ECU 60, for example. In step S204, when it is determined that the predetermined time has not elapsed (No), the ECU 60 repeats the process of step S204, and when it is determined that the predetermined time has elapsed (Yes), the process proceeds to step S205. .

  In step S205, the ECU 60 outputs an OFF command for shutting off the positive side (P side) switch 41 of the contactor 40, and shuts off the power line L1 that connects the fuel cell stack 10 and the motor PDU 30.

  Then, the process proceeds to step S206, and the ECU 60 determines whether or not a predetermined time has elapsed since the OFF command was issued in step S205. Note that the predetermined time here is also the time necessary for the positive-side switch 41 to be reliably cut off, as described above, and is determined by, for example, a timer (not shown). In step S206, when it is determined that the predetermined time has not elapsed (No), the ECU 60 repeats the process of step S206, and when it is determined that the predetermined time has elapsed (Yes), the process proceeds to step S207. .

  In step S207, the ECU 60 rewrites the order determination flag “0” stored in the memory to “1”, and ends the disconnection of the contactor 40. Further, the switch (positive electrode side) 52 of the battery contactor 51 is cut off (off), the switch (negative electrode side) 53 is cut off (off), and the power lines L3 and L4 are cut off.

  Then, when the ignition switch is turned on by the driver and a shutoff signal for shutting down the contactor 40 is output next time, in step S202 of the flow of FIG. 4, the ECU 60 determines that the order determination flag stored in the memory is It judges “1” and proceeds to step S208.

  In step S208, the ECU 60 first outputs an OFF command for shutting off the switch 41 on the positive electrode side (P side) of the contactor 40, and shuts off the power line L1 that connects the fuel cell stack 10 and the motor PDU 30. To do.

  And it progresses to step S209 and ECU60 judges whether predetermined time passed like step S206, and when it is judged that predetermined time has not passed (No), processing of step S209 is performed. If it is determined repeatedly that the predetermined time has elapsed (Yes), the process proceeds to step S210.

  In step S210, the ECU 60 outputs an OFF command for shutting off the negative side (N side) switch 42 of the contactor 40, and shuts off the power line L2 connecting the fuel cell stack 10 and the motor PDU 30.

  And it progresses to step S211, ECU60 judges whether predetermined time passed like step S204, and when it is judged that predetermined time has not passed (No), processing of step S211 is carried out. If it is determined repeatedly that the predetermined time has elapsed (Yes), the process proceeds to step S212.

  In step S212, the ECU 60 rewrites the order determination flag “1” stored in the memory to “0”, and ends the disconnection of the contactor 40. Then, when the contactor 40 is shut off next time, the processes of steps S201 to S207 are executed.

  Further, with reference to the time chart of FIG. 5, when the contactor 40 is shut off for the first time, as shown in FIG. 5A, the scavenging of the fuel cell stack 10 or the like of the fuel cell stack 10 is performed at time t4. When the voltage drops to a predetermined value (S201, Yes), an OFF command is issued to the switch 42 on the negative electrode side of the contactor 40 (S203). At this time, arc discharge occurs through the negative switch 42, and the voltage V2 on the downstream side of the contactor 40 gradually decreases. When a predetermined time (t5-t4) has elapsed from the OFF command (S204, Yes), an OFF command is issued to the positive switch 41 (time t5, S205). Then, when a predetermined time (t6-t5) has elapsed from the OFF command (S206, Yes), the order determination flag “0” is rewritten to “1” (time t6, S207).

  When the contactor 40 is shut off next time (second time), the order determination flag is “1” as shown in FIG. 5B, so that the fuel cell stack is scavenged by the scavenging of the fuel cell stack 10 at time t4. When the voltage of 10 decreases to a predetermined value (S201, Yes), an OFF command is issued to the switch 41 on the positive side of the contactor 40 (S208). At this time, arc discharge is generated via the switch 41 on the positive electrode side, and the voltage V2 on the downstream side of the contactor 40 gradually decreases. When a predetermined time (t5-t4) has elapsed from the OFF command (S209, Yes), an OFF command is issued to the negative-side switch 42 (time t5, S210). Then, when a predetermined time has elapsed from the OFF command (S211, Yes), the order determination flag “1” is rewritten to “0” (time t6, S212).

  As described above, according to the present embodiment, the timing at which the positive-side switch 41 of the contactor 40 is shut off is shifted from the timing at which the negative-side switch 42 is shut off, and the contactor 40 is shut off every time (every predetermined number of times). By changing the order, the positive switch 41 and the negative switch 42 can be alternately (equally) assigned to the occurrence of arc discharge, and the durability of the contactor 40 can be increased.

(Third embodiment)
FIG. 6 is a flowchart showing a contactor connection / disconnection method according to the third embodiment, and FIG. 7 is a timing chart according to the third embodiment. In the third embodiment, the order of connecting the positive side switch 41 and the negative side switch 42 when a connection signal for connecting the contactor 40 is issued, and the positive polarity when a cutoff signal for shutting off the contactor 40 is issued. The order in which the switch 41 on the side and the switch 42 on the negative electrode side are cut off is made equal.

  Note that steps S301, S302, S303, S304, and S305 in FIG. 6 are driving preparation periods of the fuel cell vehicle V, and are the same as steps S101, S103, S104, S105, and S106 in the first embodiment shown in FIG. It is. Also, steps S308, S309, S310, S311, and S312 in FIG. 6 are stop periods, which are the same as steps S201, S203, S204, S205, and S206, respectively, of the second embodiment shown in FIG.

  If the predetermined time has elapsed in step S305 (Yes), the process proceeds to step S306, and the ECU 60 shifts to the normal operation from the operation preparation period. In normal operation, for example, the power generated by the fuel cell stack 10 is supplied to the traveling motor 20 and the auxiliary equipment, and the high-voltage secondary battery 50 is charged as necessary.

  In step S307, the ECU 60 determines whether the ignition switch is turned off by the driver. If the ECU 60 determines that the ignition switch is not turned off (No), the ECU 60 returns to step S306 and continues normal operation. If it is determined that it has been turned off (Yes), the process proceeds to step S308.

  Further, with reference to the timing chart of FIG. 7, when the contactor 40 is connected during the operation preparation period, the switch 42 on the negative side of the contactor 40 is first turned ON (time t7), and a predetermined time (t8-t7) has elapsed. Later, the switch 41 on the positive electrode side is turned on (time t8), and the normal operation is started. When the ignition switch is turned off and the contactor 40 is shut off, the negative electrode side switch 42 of the contactor 40 is first turned off (time t9), and the positive electrode side switch 41 is turned on after a predetermined time (t10-t9). It is turned off (time t10).

  In this way, the order of connection and the order of disconnection are made equal so that when the contactor 40 is connected, the positive-side switch 41 receives an inrush current, and when the contactor 40 is disconnected, the negative-side switch 42 receives arc discharge. By doing so, it becomes possible to share the charge more evenly with respect to the switch 41 on the positive electrode side and the switch 42 on the negative electrode side.

  In the third embodiment, the case where the negative electrode side switch 42 of the contactor 40 is connected first has been described as an example. However, the present invention is not limited to this, and the positive electrode side switch 41 is connected first. You may do it.

  In the first embodiment and the second embodiment, the example in which the order is changed every time as the predetermined number of times has been described. However, the present invention is not limited to this example, and every five times, every ten times, etc. Can be changed.

1 is an overall configuration diagram showing a fuel cell vehicle to which a contactor connection / cutoff method of an embodiment is applied. It is a flowchart which shows the contactor connection / cutoff method of 1st Embodiment. It is a timing chart in a 1st embodiment. It is a flowchart which shows the connection / cut-off method of the contactor of 2nd Embodiment. It is a timing chart in a 2nd embodiment. It is a flowchart which shows the connection / cut-off method of the contactor of 3rd Embodiment. It is. It is a timing chart in a 3rd embodiment.

Explanation of symbols

10 Fuel cell stack (power source)
20 Traveling motor (load)
40 Contactor for fuel cell (contactor)
41 Positive Switch 42 Negative Switch 70 ECU
L1, L2 power line

Claims (1)

A fuel cell;
A load that receives power from the fuel cell;
A contactor for a fuel cell having an electromagnetic open / close switch for disconnecting and connecting to a positive electrode and a negative electrode on a power line connecting the fuel cell and the load, and having no precharge circuit;
A high-voltage battery connected in parallel to the fuel cell with respect to the load, supplying power to the load, and charging power generated by the fuel cell;
A DC / DC converter that boosts the voltage from the high-voltage battery at the time of startup of the fuel cell system;
A battery contactor having a switch for disconnecting connection to the positive and negative electrodes on the power line connecting the high-voltage battery and the DC / DC converter, and having a precharge circuit;
A capacitor connected between the DC / DC converter and the battery contactor;
A contactor connecting / disconnecting method in a fuel cell system comprising:
At startup of the fuel cell system,
The battery contactor is connected to one of the switches on the side where the precharge circuit is not provided and connected to the precharge circuit to start charging the capacitor, and when the charging of the capacitor is completed, the battery After disconnecting the precharge circuit after connecting the other switch of the contactor for
When the voltage on the fuel cell side of the fuel cell contactor becomes substantially equal to the voltage on the DC / DC converter side of the fuel cell contactor, a connection signal for the fuel cell contactor is output,
Wherein when issuing the connection signal for connecting the fuel cell contactor, wherein the positive electrode side of the two of the one of the switches from issuing a connection signal to one of the switches as the timing for connecting the switch and the negative electrode side switch reliably When a first predetermined time necessary for connection has elapsed, a connection signal is output to the other of the two switches to cause a shift, and for each predetermined number of times the connection signal is output, Change the order of connecting the negative side switch,
When the fuel cell system is stopped,
When a shut-off signal for shutting off the fuel cell contactor is issued, a shut-off signal is output to one of the two switches as a timing for shutting off the positive-side switch and the negative-side switch, and then the one switch is reliably shut off. When a second predetermined time necessary to do so has elapsed, a disconnection signal is output to the other of the two switches to cause a deviation, and at each predetermined number of times the interrupt signal is output, the positive-side switch and the switch Change the order of shutting off the negative side switch,
The voltage on the fuel cell side of the fuel cell contactor is the voltage on the DC / DC converter side between the cutoff of one of the two switches of the fuel cell contactor by scavenging the inside of the fuel cell. Outputs a shut-off signal of the fuel cell contactor when the value drops to a predetermined value that gradually decreases,
The order of connecting the positive side switch and the negative side switch when the connection signal is issued, and the order of cutting off the positive side switch and the negative side switch when the cutoff signal is issued Contactor connection / disconnection method characterized by equalizing

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