JP2008109724A - Power system and vehicle with power system, and diagnostic method of transmission state - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for diagnosing the transmission state of a command in a DC converter which stops operation in response to the command. <P>SOLUTION: At time T1, a shut-down command SDOWN is set forcibly in on state. At time T2 after elapsing a predetermined period, a switching command PWM2 having a duty ratio of a fixed value is output. In other words, a reciprocal state is formed after the time T2. Since a transistor Q2 is sustained in off state so long as transmission of the shut-down command SDOWN is normal, main line voltage VPN is sustained at a level substantially coincides with the battery voltage Vb. If the shut-down command SDOWN is abnormal, the transistor Q2 performs switching operation depending on the switching command PWM2 and the main line voltage VPN begins to rise. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power system including a DC converter, a vehicle including the power system, and a diagnosis method for a transmission state in the power system, and more particularly to a technique for diagnosing a transmission state of a command given to the DC converter.

  In recent years, electric vehicles such as hybrid vehicles and electric vehicles have attracted a great deal of attention as environmentally friendly vehicles. Such an electric vehicle includes a power storage device including a secondary battery, an electric motor for generating vehicle driving force, an inverter device for operating the electric motor, and the like. In order to be able to supply a voltage exceeding the counter electromotive force generated by the rotation of the electric motor and to further expand the operating range of the electric motor, a DC converter device capable of boosting the DC voltage is further interposed between the power storage device and the inverter device. Sometimes.

  A DC converter device, an inverter device, and the like are configured to operate in accordance with a control command from a control device configured by an ECU (Electrical Control Unit) or the like. The control device and the DC converter device or the inverter device are connected by a wire harness or the like, and a control command is transmitted.

  Since the control command is a very important signal for running control of the electric vehicle, a general electric vehicle has a fail-safe function for detecting a transmission failure of the control command. For example, in JP-A-8-317501 (Patent Document 1), when a communication abnormality occurs between the vehicle control device and the inverter, it is specified that the abnormality is an abnormality such as a disconnection of the communication line. A fail-safe device of an electric vehicle control device that can appropriately cope with this abnormality is disclosed.

Japanese Patent Laid-Open No. 2005-278314 (Patent Document 2) discloses a motor drive device that determines an abnormality in the entire switching command system including a controller that transmits a switching command to a switching element constituting the motor drive device, and the like. The abnormality determination method is disclosed.
JP-A-8-317501 JP 2005-278314 A

  However, the fail-safe device disclosed in Japanese Patent Application Laid-Open No. 8-317501 (Patent Document 1) detects an abnormality such as a disconnection of a communication line with respect to the inverter device based on the operating state of the motor. Moreover, the motor drive device and its abnormality determination method disclosed in Japanese Patent Laid-Open No. 2005-278314 (Patent Document 2) are for determining an abnormality of the entire switching command system for the inverter device based on a motor operation command. is there.

  These prior arts cannot be applied to a DC converter device that is not directly related to the operating state of the electric motor. In particular, a capacitor is often connected in parallel to the output side of the DC converter device. In such a case, even if the DC converter device is stopped, the output voltage before the operation is stopped is maintained. For this reason, it is impossible to diagnose the transmission state of a command for instructing operation stop, and there is a problem that it takes time and labor to specify a defective part.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a technique for diagnosing the transmission state of a command for a DC converter that stops operation in response to the command. It is to be.

  A power system according to an aspect of the present invention includes a DC converter that converts externally supplied power into DC power having a predetermined voltage and outputs the DC power, a controller that generates a control command for the DC converter, a controller, and a DC converter A transmission means provided between the apparatus and configured to transmit at least a control command generated by the control apparatus to the DC conversion apparatus; and a detection means for detecting an output voltage of the DC conversion apparatus. Then, the control device generates a first command for instructing to stop the operation of the DC converter as a control command at the time of the communication test, and a second command that cannot be realized when the first command is valid. A communication test means that occurs before the command is released, a determination means that determines whether the DC converter is operating according to the second instruction based on the detection result of the detection means during the communication test, and a determination Means for detecting a transmission abnormality of the first command when it is determined by the means that the DC converter is operating in accordance with the second command.

  According to the present invention, the first command that instructs the DC converter to stop operating is generated as the control command, and the second command that cannot be realized when the first command is valid is the first command. Occurs before release. Thereby, if the transmission of the first command is abnormal, the output of the DC converter changes according to the first command, while if the transmission of the first command is normal, the output of the DC converter is maintained as it is. Is done. Therefore, even if a capacitor or the like is connected in parallel to the output of the DC converter, it is possible to diagnose the transmission state of the first command that instructs the DC converter to stop operating.

  Preferably, the communication test means generates the second command after a predetermined period has elapsed since the generation of the first command.

  Preferably, the DC converter includes a chopper circuit capable of boosting the supplied power by repeating the accumulation and release of electromagnetic energy by a periodic switching operation, and the communication test means boosts the supplied power to a predetermined value. A second command for instructing is generated.

  Preferably, the determination unit determines that the DC converter is operating according to the second instruction when the output voltage of the DC converter increases.

  Preferably, the power system according to the present invention further includes a capacitor connected in parallel to the output of the DC converter.

  A vehicle according to another aspect of the present invention generates AC power that generates predetermined AC power from the above-described power system, a power storage device configured to be able to supply power to the power system, and DC power output from the power system. And a rotating electric machine that receives AC power generated by the AC generator and generates driving force.

  According to still another aspect of the present invention, there is provided a method for diagnosing a transmission state between a control device and a DC converter connected via a communication line. Then, the DC converter converts the externally supplied power into DC power of a predetermined voltage and outputs it, the control device generates a control command for the DC converter, and the communication line is generated at least by the controller The control command is configured to be transmitted to the DC converter. Furthermore, the transmission state diagnosis method according to the present invention generates a first command for instructing to stop the operation of the DC converter as a control command during a communication test, and cannot be realized when the first command is valid. The step of generating the two commands before the first command is released, the step of detecting the output voltage of the DC converter, and the DC converter based on the detected output voltage of the DC converter during the communication test Determining whether the DC converter is operating according to the second instruction, and detecting a transmission abnormality of the first command when it is determined that the DC converter is not operating according to the second command; including.

  According to the present invention, it is possible to realize a power system, a vehicle including the power system, and a transmission state diagnosis method capable of diagnosing the transmission state of the command for a DC converter that stops operation in response to the command.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic configuration diagram of a vehicle 100 equipped with an electric power system according to an embodiment of the present invention.

  Referring to FIG. 1, vehicle 100 is, for example, a hybrid vehicle configured to be able to travel by driving force from at least one of engine ENG and motor generators MG1 and MG2. The vehicle 100 includes an engine ENG, a power split mechanism 16, a speed reducer 18, drive wheels 20, driven wheels 22, a power control unit PCU (Power Control Unit), a power supply unit PS, and a control device ECU. (Electrical Control Unit) and motor generators MG1, MG2.

  Engine ENG burns a mixture of fuel and air to rotate a crankshaft (not shown) to generate driving force. The driving force generated by the engine ENG is divided into two paths by the power split mechanism 16. One is a path for driving the drive wheels 20 via the speed reducer 18, and the other is a path for driving the motor generator MG1 to generate power.

  Motor generators MG1 and MG2 are, for example, permanent magnet type three-phase AC synchronous rotating electric machines. Although motor generators MG1 and MG2 can both function as an electric motor (motor) and a generator (generator), in vehicle 100, motor generator MG1 mainly functions as a generator, and motor generator MG2 It is configured to function as an electric motor. That is, motor generator MG1 is configured to be able to generate electric power upon receiving the driving force of engine ENG divided by power split mechanism 16. Motor generator MG2 is arranged on the same rotating shaft as engine ENG and power split device 16, and receives AC power generated by inverter device INV2 described later to generate driving force.

  Power control unit PCU is electrically connected to motor generators MG1 and MG2 and power supply unit PS, respectively, and performs power transfer and power conversion between each other according to a control command from control device ECU. Specifically, power control unit PCU includes a DC converter device CONV and inverter devices INV1 and INV2.

  The DC converter device CONV is configured to convert (boost) the power supplied from the power supply unit PS into DC power of a predetermined voltage and output it to the inverter devices INV1 and INV2 by a periodic switching operation by the switching element. The DC converter device CONV is also configured to be able to convert (step down) the regenerative power from the inverter device INV1 or INV2 into DC power of a predetermined voltage and output it to the power supply unit PS.

  Then, as will be described later, DC converter device CONV performs a voltage conversion operation in accordance with a switching command for instructing a voltage conversion operation given from control device ECU and a shutdown command for instructing to stop the voltage conversion operation.

  Inverter devices INV1 and INV2 generate predetermined AC power from the DC power output from DC converter device CONV and supply it to motor generators MG1 and MG2, respectively. In addition, by adjusting the voltage and phase of AC power, motor generators MG1 and MG2 can be operated as electric motors or can be operated as generators, respectively.

  The power supply unit PS includes a power storage device configured to be able to supply DC power to the DC converter device, and the power storage device is configured to be chargeable / dischargeable.

  The control unit ECU executes a program stored in advance, and based on a signal transmitted from each sensor (not shown), a traveling state, a rate of change of the accelerator opening, a charging state of the power storage device, a stored map, and the like. To perform arithmetic processing. Thereby, control device ECU produces | generates a control command with respect to the mounted circuit and apparatus so that the vehicle 100 may be in a desired driving | running state according to a driver | operator's operation. Specifically, control device ECU is connected to power control unit PCU, engine ENG, and power supply unit PS via communication lines CL1, CL2, and CL3, respectively. Control device ECU transmits and receives control commands via communication lines CL1, CL2, and CL3, respectively.

  As described above, the control device ECU is configured to transmit the switching command for instructing the voltage conversion operation and the shutdown command for instructing the stop of the voltage conversion operation to the DC converter device CONV via the communication line CL1. Is done. As an example, the switching command is a PWM (Pulse Width Modulation) signal for turning on / off each switching element with a duty ratio according to a request. The shutdown command is also referred to as a high potential state (hereinafter also referred to as “ON” or “ON”) for instructing operation stop and a low potential state (hereinafter referred to as “OFF” or “OFF”) that permits operation. ) Is a binary signal that can take two states.

  DC converter device CONV performs a switching operation according to the switching command, and when the shutdown command is driven on, stops the switching operation regardless of the switching command, that is, shuts down. Therefore, in a normal control operation, one of the switching command and the shutdown command is output. That is, the switching command cannot be realized when the shutdown command is valid.

  Further, the control unit ECU generates a shutdown command to perform a communication test for transmission of the shutdown command, and at the same time releases the switching command for instructing a predetermined voltage conversion operation (for example, a predetermined duty ratio). Occurs before Then, control device ECU determines whether or not DC converter device CONV is operating according to the switching command based on the detection result of the voltage value of the DC power output from DC converter device CONV. Further, when it is determined that the DC converter device CONV is operating in accordance with the switching command, a transmission abnormality regarding the shutdown command is detected.

  That is, the control unit ECU simultaneously outputs a switching command and a shutdown command for instructing mutually contradictory operations to form a “reciprocal state”. Here, if a connection failure such as disconnection or connector disconnection occurs in the communication line for transmission of the shutdown command, the DC converter device CONV cannot receive the shutdown command from the control device ECU. Therefore, even if a shutdown command is sent from the control device ECU, the DC converter device CONV continues the voltage conversion operation according to the switching command, and thus the voltage value of the DC power output from the DC converter device CONV changes. . Therefore, when the reciprocal state is formed, the transmission state of the shutdown command can be diagnosed based on whether or not the voltage value of the DC power output from the DC converter device CONV changes.

FIG. 2 is a schematic configuration diagram showing a main part of the power system according to the embodiment of the present invention.
Referring to FIG. 2, power supply unit PS is electrically connected to DC converter device CONV through positive line PL and negative line NL. Power supply unit PS includes a power storage device BAT and system relays SR1 and SR2.

  As an example, the power storage device BAT includes a secondary battery such as a lithium ion battery or a nickel metal hydride battery, or a power storage element such as an electric double layer capacitor.

  System relays SR1 and SR2 are respectively interposed between positive line PL and negative line NL and power storage device BAT. System relays SR1 and SR2 electrically connect or disconnect power storage device BAT and DC converter device CONV in accordance with system command SE given from control unit ECU.

  Power control unit PCU includes a DC converter device CONV, inverter devices INV1 and INV2, a main positive line MPL, a main negative line MNL, a main line voltage detection unit 6, and a capacitor C2.

  DC converter device CONV is interposed between positive line PL and negative line NL and main positive line MPL and main negative line MNL. DC voltage appearing between positive line PL and negative line NL, and main positive line A DC voltage appearing between the line MPL and the main negative line MNL can be bidirectionally converted. As an example, the DC converter device CONV includes a step-up / step-down chopper circuit, and performs a switching operation in accordance with switching commands PWM1 and PWM2 from the control device ECU, thereby realizing a voltage conversion operation. Specifically, the DC converter device CONV is configured to boost the DC power supplied from the power storage device BAT and supply it to the inverter devices INV1 and INV2, and to generate DC power regenerated from the inverter devices INV1 and INV2. It is configured to be capable of being stepped down and supplied to the power storage device BAT. The step-up ratio or the step-down ratio is determined according to the duty ratio of the switching commands PWM1 and PWM2.

  More specifically, DC converter device CONV includes transistors Q1 and Q2, diodes D1 and D2, an inductor L1, a capacitor C1, a battery voltage detection unit 4, and a gate drive unit 2.

  Transistors Q1 and Q2 are connected in series between main positive line MPL and main negative line MNL. As an example, the transistors Q1 and Q2 are made of IGBT (Insulated Gate Bipolar Transistor). Alternatively, a bipolar transistor, MOSFET (Metal Oxide Semiconductor), or GTO (Gate Turn Off thyristor) may be used.

  The diode D1 is connected between the emitter and the collector of the transistor Q1 so that a feedback current can flow from the emitter side to the collector side of the transistor Q1. Similarly, the diode D2 is connected between the emitter and collector of the transistor Q2 so that a feedback current can flow from the emitter side to the collector side of the transistor Q2.

  Inductor L1 has one end connected to a connection point between transistor Q1 and transistor Q2, and the other end connected to positive line PL. Inductor L1 repeats the accumulation and release of electromagnetic energy by the current generated according to the periodic switching operation of transistors Q1 and Q2. The DC converter device CONV realizes a voltage conversion operation (step-up or step-down) by repeatedly storing and releasing electromagnetic energy in the inductor L1.

  In the step-up operation, the transistor Q1 is kept on and the transistor Q2 is periodically switched. On the other hand, in the step-down operation, the transistor Q2 is maintained in the off state, and the transistor Q1 is periodically switched.

  Capacitor C1 is connected between positive line PL and negative line NL, and smoothes (stabilizes) DC power supplied from power storage device BAT.

  Battery voltage detection unit 4 detects battery voltage Vb between positive line PL and negative line NL, and sends it to control unit ECU.

  Gate driver 2 is electrically connected to the gates of transistors Q1 and Q2, respectively, and drives transistors Q1 and Q2 so that a predetermined switching operation is performed. That is, gate drive unit 2 drives transistors Q1 and Q2 in accordance with switching commands PWM1 and PWM2 and shutdown command SDOWN given from control unit ECU.

FIG. 3 is a functional block diagram of the gate driving unit 2.
Referring to FIG. 3, gate drive unit 2 includes selection units 30 and 32. The selection unit 30 is configured to receive the switching command PWM1 and the off command, and to output one of them to the gate of the transistor Q1 in response to the shutdown command SDOWN. That is, the selection unit 30 drives the transistor Q1 according to the switching command PWM1 in a period in which the shutdown command SDOWN is maintained in the off state. On the other hand, when the shutdown command SDOWN is activated to ON, an OFF command is forcibly output to the gate of the transistor Q1. Therefore, the transistor Q1 stops the switching operation regardless of the switching command PWM1.

  The selection unit 32 is configured to receive the switching command PWM2 and the OFF command, and output either one to the gate of the transistor Q2 in response to the shutdown command SDOWN. Since the behavior of selection unit 32 is the same as that of selection unit 30, detailed description will not be repeated.

  Referring to FIG. 2 again, capacitor C2 is connected between main positive line MPL and main negative line MNL, and stabilizes the DC power exchanged between DC converter device CONV and inverter devices INV1 and INV2. Turn into. That is, the capacitor C2 functions as a power buffer.

  The main line voltage detector 6 detects the main line voltage VPN between the main positive line MPL and the main negative line MNL, and sends it to the control unit ECU. The main line voltage VPN corresponds to the voltage value of the DC power output during the step-up conversion operation of the DC converter device CONV.

  Inverter devices INV1 and INV2 are electrically connected in parallel to DC converter device CONV via main positive line MPL and main negative line MNL. As an example, the inverter devices INV1 and INV2 are configured by switching elements such as IGBTs arranged in a grid pattern. Then, inverter device INV1 generates AC power in response to drive command DRV1 from control device ECU, and supplies it to motor generator MG1. Similarly, inverter device INV2 generates AC power in response to drive command DRV2 from control device ECU, and supplies it to motor generator MG2.

  The control device ECU transmits a command to the power control unit PCU via the communication line CL1, and receives various detection results from the power control unit PCU. Then, when detecting the occurrence of the test mode request, control device ECU diagnoses the transmission state for shutdown command SDOWN. That is, control device ECU determines whether or not shutdown command SDOWN from control device ECU to DC converter device CONV can be physically transmitted. The test mode request is generated, for example, by a self-check operation after an ignition on (IGON) signal is given from the driver or a request from a diagnostic tool connected to the vehicle 100 or the like.

  FIG. 4 is a functional block diagram of the control device ECU. In the embodiment of the present invention, when the reciprocal state is formed, the switching command instructing the boosting operation is output, and the transmission state of the shutdown command SDOWN is determined based on whether the voltage of the main line voltage VPN rises. Is diagnosed. When the DC converter device CONV is boosted, the transistor Q1 (FIG. 2) is kept on and the transistor Q2 (FIG. 2) performs a switching operation.

  Referring to FIG. 4, control device ECU includes converter voltage control unit 40, modulation units 42 and 46, selection units 44 and 48, test mode detection unit 50, delay element 52, and comparison unit 54. including.

  Converter voltage control unit 40 generates a command for controlling the voltage conversion operation of DC converter device CONV during normal travel of vehicle 100. Specifically, converter voltage control unit 40 determines duty ratios Dty1 and Dty2 of transistors Q1 and Q2, respectively, according to state values such as battery voltage Vb, main line voltage VPN, and rotation speeds of motor generators MG1 and MG2. . Then, converter voltage control unit 40 outputs determined duty ratio Dty1 to modulation unit 42 and also outputs duty ratio Dty2 to selection unit 44.

  Further, converter voltage control unit 40 outputs shutdown command SDOWN to selection unit 48 in order to stop the operation of power control unit PCU in response to an ignition off signal (not shown) given by the operation of the driver or the like. To do.

  The selection unit 44 receives the duty ratio Dty2 and the constant value α, and outputs one of them as a duty ratio Dty2 to the modulation unit 46 in accordance with an activation signal ACT given from a delay element 52 described later. Specifically, the selection unit 44 forcibly outputs the constant value α as the duty ratio Dty2 when the activation signal ACT is activated.

  Modulating units 42 and 46 respectively compare duty ratio Dty1 and duty ratio Dty2 with a carrier wave (carrier wave) generated by an oscillating unit (not shown) to generate switching commands PWM1 and PWM2, respectively.

  The selector 48 receives a shutdown command SDOWN and an ON command output from the converter voltage control unit 40, and outputs either one according to an activation signal ACT described later. Specifically, the selection unit 48 forcibly sets the shutdown command SDOWN to the on state when the activation signal ACT is activated.

  As described above, the selection units 44 and 48 are elements that forcibly change the duty ratio Dty2 and the shutdown command SDOWN, respectively, in order to form a reciprocal state.

  The test mode detection unit 50 determines whether or not there is a test mode request based on an ignition on (IGON) signal from the driver or a test mode request from a diagnostic tool outside the vehicle. Then, when the occurrence of the test mode request is detected, the test mode detection unit 50 activates the activation signal ACT. Further, the activation signal ACT is transmitted to the delay element 52, the selection unit 48, and the comparison unit 54.

  When the activation signal ACT is activated by the test mode detection unit 50, the delay element 52 delays the activation signal ACT by a predetermined period and outputs the activated activation signal ACT to the selection unit 44. That is, the delay element 52 delays the start timing of the selection operation of the selection unit 44 as compared with the selection operation of the selection unit 48. Thus, after the activation signal ACT is activated, the timing at which the duty ratio Dty2 is forcibly set to a constant value α is only a predetermined period with respect to the timing at which the shutdown command SDOWN is forcibly set to ON. Delay.

  The comparison unit 54 starts comparison between the battery voltage Vb and the main line voltage VPN in response to the activation signal ACT, and when the main line voltage VPN rises higher than a predetermined threshold voltage compared to the battery voltage Vb. Then, it is determined that the transmission state of the shutdown command SDOWN is abnormal, and the determination result is output.

  Hereinafter, an example of the operation of the power system according to the present invention will be described with reference to the time waveform of each part.

  FIG. 5 is a graph showing time waveforms of respective parts of the power system according to the embodiment of the present invention.

FIG. 5A shows the switching command PWM1.
FIG. 5B shows the switching command PWM2.

FIG. 5C shows a shutdown command SDOWN.
FIG. 5D shows the state of the transistor Q2 at the normal time.

FIG. 5E shows the state of the transistor Q2 when transmission is abnormal.
FIG. 5F shows the main line voltage VPN.

  Referring to FIGS. 5A and 5B, before time T1, transistor Q1 is turned on, while transistor Q2 is kept off. That is, the voltage conversion operation of DC converter device CONV is stopped, and is maintained in a state equivalent to that where power storage device BAT is electrically connected to main positive line MPL and main negative line MNL. Therefore, as shown in FIG. 5 (f), main line voltage VPN substantially matches battery voltage Vb of power storage device BAT.

  Referring to FIGS. 4 and 5C, when test mode detection unit 50 activates activation signal ACT at time T1, selection unit 48 forcibly sets shutdown command SDOWN to an on state. Subsequently, when the activation signal ACT is output from the delay element 52 to the selection unit 44 at time T2, the selection unit 44 forcibly sets the duty ratio Dty1 to α. Then, the switching command PWM2 having a duty ratio of a constant value α is output from the modulation unit 46 (FIG. 5B). That is, a reciprocal state is formed after time T2. Since the step-up ratio in DC converter device CONV is determined by the duty ratio, switching command PWM2 instructs step-up to a voltage value corresponding to constant value α.

  Here, as shown in FIG. 3, when the shutdown command SDOWN is in the ON state, the gate driving unit 2 stops the switching operation of the transistor Q2 regardless of the switching command PWM2. Therefore, as shown in FIG. 5D, if transmission of the shutdown command SDOWN is normal, the transistors Q1 and Q2 are turned off. Here, since the charge corresponding to the battery voltage Vb is accumulated in the capacitor C2 (FIG. 2) connected in parallel to the output of the DC converter device CONV, after the transistors Q1 and Q2 are turned off, The main line voltage VPN is maintained substantially in agreement with the battery voltage Vb (FIG. 5 (f)).

  On the other hand, as shown in FIG. 5E, if the transmission of the shutdown command SDOWN is abnormal, that is, if the shutdown command SDOWN is not transmitted to the gate drive unit 2, the transistor Q2 performs a switching operation according to the switching command PWM2. As a result, as shown in FIG. 5F, the main line voltage VPN starts to rise. Therefore, it is possible to detect a transmission abnormality caused by a connection failure such as disconnection or connector disconnection based on whether or not the main line voltage VPN increases after time T2.

  FIG. 6 is a flowchart showing a processing procedure for diagnosis of a transmission state according to the embodiment of the present invention.

  Referring to FIG. 6, control unit ECU determines whether or not a test mode request has occurred (step S100). If a test mode request has not occurred (NO in step S100), control device ECU again determines whether or not a normal abnormality has occurred (step S100).

  If a test mode request has occurred (YES in step S100), control unit ECU forcibly sets shutdown command SDOWN to an on state (step S102). Then, the control device ECU waits for a predetermined period (step S104). Further, control device ECU forcibly outputs a PWM signal having a predetermined duty ratio as switching command PWM2 (step S106).

  Along with the formation of the reciprocal state due to the processing in step S102 and step S106 described above, control device ECU starts comparison between battery voltage Vb and main line voltage VPN (step S108). Then, control device ECU determines whether or not main line voltage VPN has risen more than a predetermined threshold voltage as compared with battery voltage Vb (step S110). The threshold voltage is appropriately determined according to the accuracy of the target DC converter device or voltage detection unit, but may be substantially zero. That is, it may be determined whether or not the main line voltage VPN increases.

  When main line voltage VPN rises higher than a predetermined threshold voltage as compared with battery voltage Vb (YES in step S110), control unit ECU determines that the transmission state of shutdown command SDOWN is abnormal. The determination result is output (step S112). Then, the control device ECU ends the process.

  On the other hand, when main line voltage VPN does not increase more than a predetermined threshold voltage compared to battery voltage Vb (NO in step S110), control unit ECU determines that battery voltage Vb and main line voltage VPN are not equal. It is determined whether or not a predetermined period has elapsed since the comparison was started (step S114).

  If the predetermined period has not elapsed since the comparison between battery voltage Vb and main line voltage VPN was started (NO in step S114), control unit ECU repeats the processes in and after step S110.

  When a predetermined period has elapsed since the start of comparison between battery voltage Vb and main line voltage VPN (YES in step S114), control unit ECU determines that the transmission state of shutdown command SDOWN is normal, The determination result is output (step S116). Then, the control device ECU ends the process.

  In the embodiment of the present invention, the DC converter device CONV corresponds to “DC converter”, the control device ECU corresponds to “control device”, the communication line CL1 corresponds to “transmission means”, and main line voltage detection. Unit 6 corresponds to “detection means”, shutdown command SDOWN corresponds to “first command”, switching commands PWM1 and PWM2 correspond to “second command”, and power storage device BAT becomes “power storage device”. Inverters INV1 and INV2 correspond to “AC generator”, and motor generators MG1 and MG2 correspond to “rotating electric machine”.

  According to the embodiment of the present invention, as a control command, a shutdown command for instructing to stop the operation of the DC converter device is generated, and a switching command that cannot be realized when the shutdown command is valid is generated before the shutdown command is released. Is done. Thereby, if the transmission of the shutdown command is abnormal, the output of the DC converter changes according to the shutdown command, while if the transmission of the shutdown command is normal, the output of the DC converter device is maintained as it is. Therefore, even if a capacitor or the like is connected in parallel to the output of the DC converter device, the transmission state of the shutdown command can be diagnosed.

  Therefore, it is possible to quickly identify the defective part by diagnosing the transmission state of the shutdown command.

  In the embodiment of the present invention, as an example, a case has been described in which a reciprocal state is formed using a switching command instructing a boosting operation in a DC converter configured by a step-up / step-down chopper circuit. It is not limited to. That is, a switching command for instructing a boosting operation may be used. In this case, the transmission state of the shutdown command can be diagnosed based on whether or not the voltage value of the output DC power is lowered. Further, the present invention can be applied to a DC converter capable of only a one-way conversion operation, such as a step-up chopper circuit or a step-down chopper circuit, instead of the step-up / step-down chopper circuit.

  In the embodiment of the present invention, as an example, a hybrid vehicle equipped with a power system has been described. However, the present invention describes that “the power supplied from the outside is reduced to a predetermined voltage by the periodic switching operation by the switching element. The present invention can be applied to any device as long as it includes a “DC conversion device that converts and outputs DC power”. As an example, the present invention can be applied to a fuel cell vehicle equipped with a fuel cell.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the vehicle carrying the electric power system according to embodiment of this invention. It is a schematic block diagram which shows the principal part of the electric power system according to embodiment of this invention. It is a functional block diagram of a gate drive part. It is a functional block diagram of a control device. It is a graph which shows the time waveform of each part of the electric power system according to embodiment of this invention. It is a flowchart which shows the process sequence concerning the diagnosis of the transmission state according to embodiment of this invention.

Explanation of symbols

  2 gate drive unit, 4 battery voltage detection unit, 6 main line voltage detection unit, 16 power split mechanism, 18 speed reducer, 20 drive wheel, 22 driven wheel, 30, 32 selection unit, 40 converter voltage control unit, 42, 46 modulation Unit, 44, 48 selection unit, 50 test mode detection unit, 52 delay element, 54 comparison unit, 100 vehicle, BAT power storage device, C1, C2 capacitor, CL1, CL2, CL3 communication line, CONV DC converter device, D1, D2 Diode, ECU control device, ENG engine, INV1, INV2 inverter device, L1 inductor, MG1, MG2 motor generator, MNL main negative wire, MPL main positive wire, NL negative wire, PL positive wire, PCU power control unit, PS power supply unit , Q1, Q2 transistors, SR1, SR2 system Leh.

Claims (7)

A DC converter that converts externally supplied power into DC power of a predetermined voltage and outputs it;
A control device for generating a control command for the DC converter;
Transmission means provided between the control device and the DC converter, and configured to transmit at least the control command generated by the controller to the DC converter;
Detecting means for detecting the output voltage of the DC converter,
The controller is
At the time of a communication test, a first command for instructing to stop the operation of the DC converter is generated as the control command, and a second command that cannot be realized when the first command is valid is used as the first command. Communication test means that occurs before is released,
Determination means for determining whether the DC converter is operating according to the second instruction based on a detection result of the detection means during the communication test;
A power system comprising: a detecting unit that detects a transmission abnormality of the first command when the determining unit determines that the DC converter is operating according to the second command.   2. The power system according to claim 1, wherein the communication test unit generates the second command after a lapse of a predetermined period from the generation of the first command. The DC converter includes a chopper circuit capable of boosting the supplied power by repeatedly storing and releasing electromagnetic energy by a periodic switching operation.
3. The power system according to claim 1, wherein the communication test unit generates the second command instructing boosting of the supplied power to a predetermined value.   The power system according to claim 3, wherein the determination unit determines that the DC converter is operating in accordance with the second instruction when an output voltage of the DC converter increases.   The power system according to claim 1, further comprising a capacitor connected in parallel to the output of the DC converter. The power system according to any one of claims 1 to 5,
A power storage device configured to be able to supply the supplied power to the power system;
An alternating current generating device that generates predetermined alternating current power from direct current power output from the power system;
A vehicle comprising: a rotating electrical machine that receives AC power generated by the AC generator and generates driving force. A method for diagnosing a transmission state between a control device and a DC converter connected via a communication line,
The DC converter converts externally supplied power into DC power of a predetermined voltage and outputs it,
The control device generates a control command for the DC converter,
The communication line is configured to transmit at least the control command generated by the control device to the DC converter,
The diagnostic method includes:
At the time of a communication test, a first command for instructing to stop the operation of the DC converter is generated as the control command, and a second command that cannot be realized when the first command is valid is used as the first command. Steps that occur before is released,
Detecting an output voltage of the DC converter;
Determining whether the DC converter is operating in accordance with the second instruction based on the detected output voltage of the DC converter during the communication test;
Detecting a transmission abnormality of the first command when it is determined that the DC converter is not operating in accordance with the second command.

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