JP2008011639A - Dc/dc converter control method, electric vehicle system, and hybrid vehicle system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DV30 (down-verter) control method that makes it possible to control the drive of the DV30, even if a communication failure occurs between a main controller 34 and a DV controller 32. <P>SOLUTION: This is the control method of the DV30 connected to a high-voltage battery 10 via a precharge contactor 22 and a main contactor 25. The DV controller 32 monitors an input voltage V2 of the DV30. In a prescribed period of time after the input voltage V2 of the DV30 connected to the precharge contactor 22 is raised up to a connectable voltage of the main contactor 25, the DV controller 32 starts the DV30 by its own judgment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a DC / DC converter control method, an electric vehicle system, and a hybrid vehicle system.

  In electric vehicles such as EVs (Electrical Vehicles) and HEVs (Hybrid Electrical Vehicles), a vehicle driving motor is driven by a high voltage power source such as a fuel cell or a high voltage battery (hereinafter referred to as “high voltage battery”). Is driving. This high voltage power supply is connected to a 12V battery and other devices via a DC / DC converter such as a downverter (hereinafter referred to as “DV”).

  FIG. 10 is a block diagram of a conventional DV control system. In this control system, the high voltage battery 10 is connected to the 12V battery 40 and other devices 42 via the DV 30. The high voltage battery 10 is connected to the DV 30 via a contactor (contact) 20. The contactor 20 includes a main contactor 25 (25a, 25b) for directly connecting the high voltage battery 10 and the DV 30, and a precharge contactor 22 for precharging the DV 30. The control system also includes a DV control unit 32 that controls the operation of the DV 30 and a main control unit 34 that controls the entire system in conjunction with an ignition switch (hereinafter referred to as “SW”) 50. .

  FIG. 3 is a timing chart at the start of DV operation. When the SW is turned on, first, the precharge contactor 22 is turned on, and then the main contactor N side 25b is turned on. Thereby, precharging of the input voltage V2 of the DV30 is started. When the input voltage V2 of the DV 30 approaches the output voltage V1 of the high voltage battery 10, the main contactor P side 25a is turned on. Thereby, the high voltage battery 10 can be connected to the DV 30 without causing welding of the main contactor.

When the precharge is completed and the high voltage battery 10 is connected to the DV 30, the main control unit 34 outputs a DV operation (start) request to the DV control unit 32. The DV control unit 32 starts the DV 30 according to the DV start request. Thereby, electric power is supplied from the high voltage battery 10 to the 12V battery 40 and the other devices 42.
JP 2001-69612 A JP 2003-324801 A

  In the DV control system shown in FIG. 10, when a communication abnormality occurs between the main control unit 34 and the DV control unit, the DV control unit 32 cannot receive the DV start request and starts the DV 30. There is a problem that it becomes impossible.

Further, when communication abnormality occurs between the main control unit 34 and the DV control unit, the DV 30 cannot be stopped.
FIG. 11 is a timing chart of the DV control method according to the prior art. When the SW is turned off, the main control unit 34 transmits a DV operation (stop) request to the DV control unit 32, and the DV control unit 32 stops the DV 30 in accordance with the DV stop request. Next, after waiting for about 100 msec until the DV is surely stopped, the main control unit 34 turns off the main contactor P side 25a. Here, when a communication abnormality occurs between the main control unit 34 and the DV control unit 32, the DV control unit 32 cannot receive a DV stop request, and the DV 30 cannot be stopped. For this reason, the input voltage to the DV 30 leaks downstream. Even if the SW is turned on here and the precharge of the DV 30 is resumed, the precharge voltage leaks to the downstream side of the DV 30, so that the precharge cannot be completed.

  As measures against this, a configuration that prohibits restarting of the DV 30 when communication is abnormal, a configuration in which the DV control unit 32 receives the SW connection / disconnection signal, a configuration in which the communication line between the main control unit 34 and the DV control unit 32 is made redundant, A configuration in which a power supply relay of the DV control unit is separately provided and controlled by the main control unit is conceivable. However, any configuration leads to an increase in weight, size, and cost.

  Therefore, an object of the present invention is to provide a control method for a DC / DC converter that can control the operation of the DC / DC converter even if a communication abnormality occurs. Another object of the present invention is to provide a fuel cell vehicle system and a hybrid vehicle system that are excellent in reliability and merchantability.

  In order to solve the above-described problem, the invention according to claim 1 is directed to a power source (for example, a precharge contactor (for example, precharge contactor 22 in the embodiment)) and a main contactor (for example, main contactor 25 in the embodiment). A method for controlling a DC / DC converter (for example, a downverter (DV) 30 in the embodiment) connected to the high-voltage battery 10) in the embodiment, wherein the precharge contactor is connected to the input voltage of the DC / DC converter. Is increased to a predetermined value (for example, ST20 in the embodiment), and after a predetermined time has passed (for example, ST28 in the embodiment), the DC / DC converter is started (for example, ST30 in the embodiment). This is a method for controlling a DC / DC converter.

  The invention according to claim 2 is characterized in that the DC / DC converter is stopped when the main contactor is disconnected and the input voltage of the DC / DC converter drops to a predetermined value. Is the method.

  According to a third aspect of the present invention, the main control unit that controls connection / disconnection of the precharge contactor and the main contactor (for example, the main control unit 34 in the embodiment) is configured so that the DC / DC converter is disconnected when the precharge contactor is disconnected. The DC / DC converter control unit (for example, the DV control unit 32 in the embodiment) that controls the operation of the DC / DC converter receives the DC / DC converter start request and outputs the DC / DC converter operation request. When the DC / DC converter is started and the start request cannot be received (for example, ST10 in the embodiment), the DC / DC converter control unit performs the DC / DC converter control method according to claim 1. And starting the DC / DC converter. It is a method.

  According to a fourth aspect of the present invention, a main control unit that controls connection / disconnection of the precharge contactor and the main contactor outputs a stop request for the DC / DC converter when the main contactor is disconnected, and the DC / DC converter The DC / DC converter control unit that controls the operation of the DC / DC converter receives the stop request for the DC / DC converter, stops the DC / DC converter, and controls the DC / DC converter control in a state where the stop request cannot be received. According to a second aspect of the present invention, there is provided a method for controlling a DC / DC converter, characterized in that the unit implements the DC / DC converter control method according to claim 2 and stops the DC / DC converter.

  According to a fifth aspect of the present invention, there is provided an electric vehicle system that implements the DC / DC converter control method according to the third or fourth aspect.

  The invention according to claim 6 is a hybrid vehicle system that implements the DC / DC converter control method according to claim 3 or claim 4.

  According to the first aspect of the present invention, even when a communication abnormality occurs, it is possible to accurately estimate the disconnection of the precharge contactor and to quickly start the DC / DC converter.

  According to the second aspect of the present invention, even when a communication abnormality occurs, the DC / DC converter can be stopped in conjunction with the disconnection of the main contactor. Accordingly, the DC / DC converter can be re-precharged and the DC / DC converter can be restarted quickly.

  According to the invention of claim 3, when the communication is normal, the DC / DC converter start request accompanying the disconnection of the precharge contactor is received, and when the communication is abnormal, the disconnection of the precharge contactor is accurately estimated, and the DC / DC converter can be started.

  According to the invention of claim 4, when the communication is normal, the DC / DC converter stop request accompanying the disconnection of the main contactor is received, and when the communication is abnormal, the DC / DC converter is quickly activated in conjunction with the disconnection of the main contactor. Can be stopped.

  According to the fifth aspect of the present invention, the operation of the DC / DC converter can be controlled even when a communication abnormality occurs in the electric vehicle system. Therefore, it is possible to provide an electric vehicle system that is excellent in reliability and merchantability.

  According to the invention which concerns on Claim 6, even when communication abnormality generate | occur | produces in a hybrid vehicle system, it becomes possible to control the driving | operation of a DC / DC converter. Therefore, it is possible to provide a hybrid vehicle system that is excellent in reliability and merchantability.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of a DV control system according to the embodiment. In this system 1, a high voltage power source is connected to a 12V battery and other devices via a DC / DC converter. As the high voltage power source, the high voltage battery 10 is employed in FIG. 1, but a fuel cell or the like can also be employed. As the DC / DC converter, a downverter (hereinafter referred to as “DV”) is employed in FIG.

  The high voltage battery 10 is connected to the DV 30 via a contactor (contact) 20. The contactor 20 includes a main contactor 25 (P side 25a and N side 25b) for directly connecting the high voltage battery 10 and the DV 30, and a precharge contactor 22 for precharging the DV 30. The precharge contactor 22 is connected in series to the precharge resistor 23 and is connected in parallel to the main contactor P side 25a.

  By connecting the precharge contactor 22 and the main contactor N side 25b together, the high voltage battery 10 precharges the input voltage V2 of the DV30. After the precharge is completed, the high voltage battery 10 and the DV 30 are directly connected by connecting the main contactor P side 25a (the precharge contactor 22 is disconnected).

  The system 1 is provided with a main control unit 34 that controls the entire system in conjunction with an ignition switch (hereinafter referred to as “SW”) 50. The main control unit 34 can monitor the output voltage V1 of the high voltage battery 10 and the input voltage V2 of the DV 30 to control the connection / disconnection of the contactor 20. The main control unit 34 is connected to a DV control unit 32 that controls the operation of the DV 30. The DV control unit 32 receives the DV operation request (start request and stop request) transmitted from the main control unit 34 and controls the operation of the DV 30. In addition to this, the DV control unit 32 of the present embodiment can control the operation of the DV 30 even with its own judgment while monitoring the input voltage V 2 of the DV 30.

  FIG. 2 is a block diagram of the power supply configuration. The DV 30 is driven by a 12V battery 40. The main control unit 34 is connected to the 12V battery 40 via the SW 50. The DV control unit 32 and the other device 42 are connected to the 12V battery 40 via relays 51 and 52. The connection / disconnection of the relays 51 and 52 is controlled by the main control unit 34.

Next, the control method of the DC / DC converter according to the first embodiment will be described based on the timing chart.
FIG. 3 is a timing chart of a DV starting method when communication is normal. In general, if the main contactor 25 is connected in a state where the potential difference between the output voltage V1 of the high voltage battery 10 and the input voltage V2 of the DV 30 is large, a large current may flow from the high voltage battery 10 to the DV 30 and the main contactor 25 may be welded. is there. Therefore, at the start of a vehicle having a large potential difference between them, the input voltage V2 of the DV 30 is precharged before the main contactor 25 is connected.

  Specifically, when SW is turned on, the main control unit 34 turns on the precharge contactor 22, and then turns on the main contactor N side 25b. Thereby, precharge of DV30 is started and the input voltage V2 of DV30 rises. At this time, the current flowing from the high voltage battery 10 into the DV 30 is limited by the precharge resistor 23. When the input voltage V2 of the DV 30 approaches the output voltage V1 of the high voltage battery 10 and the potential difference between them becomes sufficiently small, the main control unit 34 turns on the main contactor P side 25a (the precharge contactor 22 is Off). Thereby, the high voltage battery 10 is directly connected to the DV 30.

  When the precharge is completed and the high voltage battery 10 is directly connected to the DV 30, the main control unit 34 sends a DV operation request (start request, ON request) to the DV control unit 32. The DV control unit 32 that has received this DV start request outputs a DV operation command (start command, ON command) to the DV 30 to start the DV 30. As described above, in a state where the communication between the main control unit 34 and the DV control unit 32 is normally performed and the DV control unit 32 can receive the DV start request from the main control unit 34, the DV control unit 32 according to the DV start request. Starts DV30.

In contrast, when a communication abnormality occurs between the main control unit 34 and the DV control unit 32 shown in FIG. 1 and the DV control unit 32 cannot receive a DV start request from the main control unit 34, the DV control unit 32 starts DV30 by its own judgment.
FIG. 4 is a timing chart of a DV starting method when communication is abnormal. First, the main control unit 34 controls connection / disconnection of the contactor 20 in the same manner as described above. That is, the high voltage battery 10 is directly connected to the DV 30 and the precharge contactor 22 is turned off. Here, even if a DV start request is transmitted from the main control unit 34 to the DV control unit 32, the DV control unit 32 cannot receive the DV operation request because a communication abnormality has occurred between them.

  Therefore, the DV control unit 32 monitors the input voltage V2 of the DV 30, and starts the DV 30 with its own judgment after a predetermined time has elapsed after the precharge contactor 22 is connected and the input voltage V2 of the DV 30 rises to a predetermined value. Here, it is desirable to set the predetermined value of the input voltage V2 to a connectable voltage on the main contactor P side 25a. The connectable voltage on the main contactor P side 25a is a voltage at which the potential difference from the output voltage V1 of the high-voltage battery 10 becomes small to the extent that welding does not occur even when the main contactor P side 25a is connected. The predetermined time is set to a time from when the input voltage V2 rises to a predetermined value until the precharge contactor 22 is disconnected. If the predetermined value of the input voltage V2 is set to the connectable voltage on the main contactor P side 25a, the predetermined time until the precharge contactor 22 is disconnected becomes substantially constant.

  Thus, if the predetermined time elapses after the input voltage V2 of the DV 30 rises to a predetermined value, it is possible to accurately estimate the disconnection of the precharge contactor 22. At this time, the DV control unit starts the DV 30 with its own judgment, so that the DV 30 can be started almost simultaneously with the disconnection of the precharge contactor 22. Therefore, even when a communication abnormality occurs, the DV 30 can be started quickly. Even if the precharge contactor 22 is not actually disconnected, the DV 30 can be started.

Next, the operation of the above-described DV control unit 32 will be described based on a flowchart.
FIG. 5 is a flowchart of the operation of the DV control unit. In ST10, it is determined whether a communication abnormality has occurred with the main control unit 34. If YES, the process proceeds to ST20, and if NO, the process proceeds to ST12. In ST12, the time counter is reset, and further proceeds to ST14. In ST14, it is determined whether a DV start request has been received from the communicable main control unit 34. If the determination is NO, the process proceeds to ST16, outputs an OFF command to the DV 30, and maintains the DV 30 in a stopped state. If the determination is YES (when a DV start request is received), the process proceeds to ST18, an ON command is output to DV30, and DV30 is started.

On the other hand, if it is determined in ST10 that a communication abnormality has occurred with the main control unit 34, the process proceeds to ST20 and it is determined whether the input voltage V2 of the DV 30 is equal to or higher than a predetermined value. If the determination is NO, the time counter is reset in ST22, and the process proceeds to ST26 via ST24. In ST26, an OFF command is output to DV30, and DV30 is maintained in a stopped state.
On the other hand, if the determination in ST20 is YES (when the DV input voltage V2 is equal to or greater than a predetermined value), the process proceeds to ST28, where it is determined whether a predetermined time has elapsed since the DV input voltage V2 became equal to or greater than the predetermined value. The determination of whether the predetermined time has elapsed is performed by determining whether the time counter is equal to or greater than a predetermined value. If the determination is NO, the process proceeds to ST24 and the time counter is added, and further proceeds to ST26 and the DV 30 is maintained in the stopped state. If the determination in ST28 is YES (when a predetermined time has elapsed), the process proceeds to ST30, an ON command is output to DV30, and DV30 is started.

Here, the alternative starting method of DV at the time of communication abnormality is examined.
FIG. 6 and FIG. 7 are timing charts of an alternative starting method for DV when communication is abnormal. In the present embodiment described above, the DV is started after a predetermined time has elapsed since the input voltage V2 of the DV has increased to a predetermined value. However, in the alternative starting method shown in FIG. 6, the power supply relay of the DV control unit 32 is turned on. After a predetermined time has elapsed, DV is started. The predetermined time is set to a time from when the power supply relay of the DV control unit 32 is turned on to when the connection / disconnection of the contactor 20 is completed (the main contactor P side is turned on). Even in this case, it is considered that DV can be started when communication is abnormal.

  However, when the SW is turned on, the main control unit 34 turns on the contactor after completion of the initial check, but this initial check time may vary. In addition, when the DV 30 is restarted with the SW-ON immediately after the SW-OFF, the previous charge may remain as the initial voltage of the input voltage V 2 of the DV 30. Therefore, the time from when the power supply relay of the DV control unit 32 is turned on to when the connection / disconnection of the contactor 20 is completed may vary greatly as shown in FIG. In this case, it is necessary to set the longest time until the contactor 20 is completely connected to a predetermined time. As a result, the time from when the actual precharge contactor 22 is disconnected (when the main control unit 34 should issue a DV start request) until the DV control unit 32 starts the DV 30 is wasted, and the DV 30 can be quickly turned on. There is a problem that it cannot be started.

  In contrast, in the DV30 control method according to the present embodiment, the DV30 is started after a predetermined time has elapsed since the input voltage V2 of the DV30 has increased to the connectable voltage of the main contactor 25. The time from when the input voltage V2 of the DV 30 rises to the connectable voltage of the main contactor 25 until the precharge contactor 22 is disconnected is substantially constant. By setting the time to a predetermined time, the DV 30 can be started substantially simultaneously with the disconnection of the precharge contactor 22. Therefore, even when a communication abnormality occurs, the DV 30 can be started quickly.

  In the first embodiment, when communication is normal, the DV control unit 32 starts the DV 30 in accordance with a DV start request from the main control unit 34, and when communication is abnormal, the DV control unit 32 starts the DV 30 with its own judgment. Alternatively, the DV control unit 32 can independently start the DV 30 in the same way as when the communication is abnormal when the communication is normal.

(Second Embodiment)
Next, a DV control method according to the second embodiment of the present invention will be described.
The DV control method according to the second embodiment is a DV stop method, and when the main contactor 25 is disconnected and the input voltage V2 of the DV 30 drops to a predetermined value, the DV control unit 32 makes an independent judgment. Is to stop. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

  First, a method for stopping DV when communication is normal will be described with reference to FIG. When the ignition switch (SW) is turned OFF at time A, the main control unit 34 sends a DV operation (stop) request to the DV control unit 32, and the DV control unit 32 stops the DV 30 in accordance with the DV stop request. Next, after waiting for about 100 msec, the main control unit 34 turns off the main contactor P side 25a. Since there is a device that operates even after the SW is turned off, the power relay of the DV control unit 32 remains on.

  However, when a communication abnormality occurs between the main control unit 34 and the DV control unit 32, the DV control unit 32 cannot receive the DV stop request, and the operation of the DV 30 is continued. Thereafter, when the SW is turned ON at time B and the precharge of the DV 30 is resumed, the precharge voltage from the high voltage battery 10 leaks to the downstream side of the DV 30 that is continuing to operate. As a result, it takes a long time to precharge the DV 30, or the precharge cannot be completed. Along with this, there is a problem that DV cannot be restarted quickly. As a countermeasure, it is conceivable that the DV control unit 32 is temporarily turned off and the DV 30 is stopped. However, in this case, a complicated system and control for turning off the power of the DV control unit 32 are required.

  FIG. 8 is a timing chart of the DV control method according to the second embodiment. In the second embodiment, the DV control unit 32 monitors the input voltage V2 of the DV 30, and when the input voltage V2 of the DV 30 drops to a predetermined value due to the disconnection of the main contactor 25, the DV 30 is stopped by an original judgment. Here, it is desirable to set the predetermined value of the input voltage V2 to a connectable voltage on the main contactor P side 25a. When the input voltage V2 is lower than the connectable voltage on the main contactor P side 25a, there is a high probability that the main contactor 25 is disconnected, and it is not possible to output a sufficient voltage downstream of the DV 30, and it is necessary to operate the DV. Is low.

  If the DV 30 is thus stopped, the input voltage to the DV 30 will not leak to the downstream side. Therefore, when SW is turned on at time B and the main control unit 34 turns on the precharge contactor 22 and the main contactor N side 25b, the DV30 can be precharged normally. Therefore, DV can be restarted quickly.

In the second embodiment, when the communication is normal, the DV control unit 32 stops the DV 30 according to the DV stop request from the main control unit 34, and when the communication is abnormal, the DV control unit 32 stops the DV 30 by its own judgment. Alternatively, the DV control unit 32 can independently stop the DV 30 in the same way as when communication is abnormal even when communication is normal.
Moreover, it is also possible to set it as the DV control system which can implement both the DV starting method which concerns on 1st Embodiment, and the DV stopping method which concerns on 2nd Embodiment.

(Third embodiment)
In the third embodiment, an electric vehicle system that implements the DV control method according to the first and second embodiments will be described.
FIG. 9 is a block diagram of the electric vehicle system. Among electric vehicles, a fuel cell vehicle includes a fuel cell (FC) stack 60. The FC stack 60 is of a type in which a reaction gas is electrochemically reacted to obtain electric power. For example, the FC stack 60 is configured by stacking a plurality of cells in which a solid polymer electrolyte membrane is sandwiched between an anode and a cathode. Hydrogen gas is supplied as a fuel gas to the anode, and air containing oxygen is supplied as an oxidant gas to the cathode. Then, hydrogen ions generated by a catalytic reaction at the anode pass through the solid polymer electrolyte membrane and move to the cathode, and cause an electrochemical reaction with oxygen at the cathode to generate water, thereby generating power.

  The fuel cell vehicle includes a motor 64 for driving the vehicle and a motor drive unit (MOTPDU) 62 that controls the drive of the motor 64. The FC stack 60 described above is connected to the MOTPDU 62 via the contactor 70 and drives the motor 64. The motor 64 is also driven by electric power supplied from the high voltage battery 10. Therefore, the input side of DV30 and the input side of MOTPDU 62 are connected.

  When the input voltage of DV30 is precharged by high voltage battery 10, the input voltage of MOTPDU 62 is also precharged. If the contactor 70 is connected here, the FC stack 60 can be connected to the MOTPDU 62 while preventing the contactor 70 from being welded. Therefore, it is not necessary to provide the precharge contactor in the contactor 70.

  The electric vehicle system 101 of the third embodiment is configured so that the DV control method of the first embodiment and the second embodiment can be implemented. Therefore, even when a communication abnormality occurs, it is possible to control the operation of DV30. Therefore, it is possible to provide the electric vehicle system 101 that is excellent in reliability and merchantability.

The present invention is not limited to the above embodiment.
For example, it is also possible to configure the hybrid vehicle system so that the DV control method of the first embodiment and the second embodiment can be implemented. Thereby, even when communication abnormality occurs, it becomes possible to control the operation of the DC / DC converter. Therefore, it is possible to provide a hybrid vehicle system that is excellent in reliability and merchantability.

It is a block diagram of the control system of DV concerning an embodiment. It is a block diagram of a power supply structure. It is a timing chart of the starting method of DV at the time of normal communication. It is a timing chart of the starting method of DV at the time of communication abnormality. It is a flowchart of operation | movement of a DV control part. It is a timing chart of the alternative starting method of DV at the time of communication abnormality. It is a timing chart of the alternative starting method of DV at the time of communication abnormality. It is a timing chart of the DV stop method concerning a 2nd embodiment. 1 is a block diagram of a system in a fuel cell vehicle. It is a block diagram of the control system of DV concerning a prior art. It is a timing chart of the stop method of DV concerning a prior art.

Explanation of symbols

  V1 ... Output voltage V2 ... Input voltage 10 ... High voltage battery (power supply) 20 ... Contactor 22 ... Precharge contactor 25 ... Main contactor 30 ... DV (DC / DC converter) 32 ... DV controller (DC / DC converter controller) 34 ... Main control unit

Claims (6)

A method for controlling a DC / DC converter connected to a power supply via a precharge contactor and a main contactor,
A method for controlling a DC / DC converter, comprising: starting the DC / DC converter after a predetermined time has elapsed after the precharge contactor is connected and the input voltage of the DC / DC converter has risen to a predetermined value.   2. The method of controlling a DC / DC converter according to claim 1, wherein the DC / DC converter is stopped when the main contactor is disconnected and the input voltage of the DC / DC converter drops to a predetermined value. The main control unit that controls connection / disconnection of the precharge contactor and the main contactor outputs a start request for the DC / DC converter after the precharge is completed,
The DC / DC converter control unit for controlling the operation of the DC / DC converter receives the start request for the DC / DC converter and starts the DC / DC converter.
The DC / DC converter control unit executes the DC / DC converter control method according to claim 1 to start the DC / DC converter in a state where the start request cannot be received. DC converter control method. The main controller that controls connection / disconnection of the precharge contactor and the main contactor outputs a stop request for the DC / DC converter before the main contactor is disconnected,
The DC / DC converter control unit for controlling the operation of the DC / DC converter receives the stop request for the DC / DC converter and stops the DC / DC converter.
The DC / DC converter control unit performs the DC / DC converter control method according to claim 2 to stop the DC / DC converter in a state where the stop request cannot be received. DC converter control method.   An electric vehicle system, wherein the method for controlling a DC / DC converter according to claim 3 or 4 is implemented.   A hybrid vehicle system, wherein the DC / DC converter control method according to claim 3 or 4 is implemented.

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