JP2008289326A - Power system and vehicle including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power system which securely and safely precharge, and a vehicle including it. <P>SOLUTION: If a short circuit fault is generated in a transistor Q2 which constitutes a boosting converter 12, a short circuit current Is is generated which flows through a route including the transistor Q2 in which the short circuit fault is generated, in addition to a precharge current Ipr, during prechrage operation. In such a case, if a short circuit portion has a relatively high resistance value, a charging voltage VL of a capacitor C1 rises up to a voltage value corresponding to a product of the short circuit current Is and the resistance value of the transistor Q2 in which the short circuit fault is generated. As a result, completion of the precharge operation is determined based on a converter current IDH flowing through a bidirectional converter 42, in addition to the charging voltage VL of the capacitor C1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power system having at least two voltage systems and a vehicle including the same, and more particularly to a control method for precharging the other voltage system using the power of one voltage system.

  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 supply device made of a secondary battery and the like, and an electric motor that can generate vehicle driving force by receiving power supplied from the power supply device. By the way, since the electric power required to generate the vehicle driving force is relatively large, the output voltage of the power supply apparatus is set to a voltage (for example, 12V or 24V) used in a conventional automobile equipped with only an internal combustion engine. Highly designed compared to. As an example, the output voltage of a hybrid vehicle currently in practical use is designed to be 288V.

  On the other hand, even in an electric vehicle as described above, devices that operate at the same voltage as that of conventional automobiles are used for auxiliary machines such as lights and car navigation devices. Therefore, an electric vehicle is equipped with a low-voltage power supply device that supplies electric power to auxiliary machinery in addition to a high-voltage power supply device that supplies electric power used to generate vehicle driving force.

  Furthermore, JP 2003-061209 A (Patent Document 1), JP 2002-176704 A (Patent Document 2), JP 2006-246564 A (Patent Document 3), etc. A configuration for electrically connecting a high-voltage power supply device and a low-voltage power supply device is also disclosed.

By the way, when power is supplied to a high-voltage load, precharging is performed in which a capacitive component (capacitor) connected in parallel to the load is pre-charged with the load stopped. In this precharge, it is common to connect a limiting resistor in series to a high-voltage power supply device and charge the capacitor while limiting so that an excessive current (inrush current) does not flow. On the other hand, in the power supply device disclosed in Japanese Patent Laid-Open No. 2003-061209 (Patent Document 1), a DC-DC converter (bidirectional converter) is controlled, and a capacitor is supplied by power supplied from the low-voltage power supply device. Is disclosed. According to the present invention, it is possible to reduce limiting resistors and switches for limiting inrush current.
JP 2003-061209 A JP 2002-176704 A JP 2006-246564 A

  On the other hand, it is necessary to consider the short circuit failure of the load. That is, if a short-circuit failure has occurred in the load connected to the high-voltage system, it is not allowed to supply power to the load from the viewpoint of safety.

  In the power supply device disclosed in the above-mentioned JP-A-2003-061209 (Patent Document 1), when the voltage of the capacitor reaches a voltage within a predetermined allowable voltage range from the stored voltage of the main battery (high-voltage power supply device), It is determined that the precharge operation is completed, and the main battery is electrically connected to the supply path. By the way, there are various modes of short-circuit faults in the load. For example, when a short-circuit fault occurs with a relatively large resistance value, the charging current from the DC-DC converter flows through the short-circuit fault site, so that apparent voltage conditions Is also expected to be satisfied. For this reason, it is determined that the precharge operation is completed despite the occurrence of a short-circuit failure in the load, and there is a possibility that power is supplied from the main battery to the load in which the short-circuit failure has occurred.

  The present invention has been made to solve such problems, and an object of the present invention is to provide an electric power system capable of performing precharge more reliably and safely and a vehicle including the same.

  A power system according to an aspect of the present invention includes a first DC power supply, a power supply line pair for supplying DC power to the first load group, a capacitor connected between the power supply line pairs, The relay unit connected between the DC power source and the power line pair, the second DC power source, both connected between the second DC power source and the power line pair and capable of bidirectional power conversion Direction converter, voltage detection means for detecting the charging voltage of the capacitor, current detection means for detecting the current flowing in the bidirectional converter, and a state in which the first DC power supply and the power line pair are electrically disconnected by the relay unit And a precharge means for charging the capacitor using the power supplied from the second DC power supply. Then, the precharge means controls the precharge operation based on the charging voltage value detected by the voltage detection means and the current value detected by the current detection means.

  According to the present invention, when charging a capacitor connected between lines of a power line pair, the charging state is determined based on the charging voltage of the capacitor, and based on the current supplied from the bidirectional converter to the power line pair. Whether or not the current is originally supplied to the capacitor can be determined. Therefore, for example, when a short-circuit fault or the like occurs in the first load group, the current value increases by an amount corresponding to the short-circuit current due to the short-circuit fault compared to the current value originally supplied to the capacitor. Abnormalities such as short-circuit faults can be detected. Therefore, precharge can be executed more reliably and safely.

  Preferably, the precharge means includes a first comparison means for comparing a charging voltage value detected by the voltage detection means with a first threshold value, a current value detected by the current detection means and a second value. A second comparing means for comparing the threshold value and a first comparing means for determining that the precharge operation is completed when the charging voltage value is larger than the first threshold value and the current value is smaller than the second threshold value; And a stopping means for stopping charging of the capacitor by the bidirectional converter when it is determined by the first determining means that the precharge operation is completed.

  Further preferably, the precharge means continues with the third comparison means for comparing the current value detected by the current detection means with the third threshold value, and the state where the current value is larger than the third threshold value. And a second determination means for measuring time and determining that an abnormality has occurred in a portion electrically connected to the power supply line pair when the duration is longer than a fourth threshold value.

  More preferably, the precharge means stops the power conversion operation in the bidirectional converter and determines the electrical connection between the first DC power source and the power line pair when the second determination means determines that an abnormality has occurred. Further included is an abnormality treatment means for prohibiting.

  Preferably, the precharge means includes first control means for controlling the power conversion operation of the bidirectional converter so that the charging voltage detected by the voltage detection means substantially matches the output voltage of the first DC power supply. In addition.

  Preferably, the first load group includes an inverter device that converts supply power from the first DC power source into AC power by a switching operation of the switching element, and the inverter device is maintained in a stopped state during precharging. Is done.

  Preferably, in the power system according to this aspect, after the completion of the precharge operation, the relay unit electrically connects the first DC power supply and the power line pair, and the connection means first DC power supply. And a second control means for controlling the power conversion operation of the bidirectional converter so that the second DC power supply is charged with the power supplied from the first DC power supply after the power supply line pair is electrically connected. And a fourth comparison means for comparing the current value detected by the current detection means with the fifth threshold value, and if the current value is smaller than the fifth threshold value, it is determined that an abnormality has occurred in the bidirectional converter. And a third determination means.

  Also preferably, the power system according to this aspect is provided between the second load group electrically connected to the second DC power source and a current value detected by the current detection means for the rated value of the bidirectional converter. The apparatus further includes a calculating unit that calculates a margin amount and a limiting unit that limits power consumption in the second load group based on the margin amount calculated by the calculating unit.

  According to another aspect of the present invention, the vehicle includes the above-described power system, and the first load group is configured to be able to generate a vehicle driving force by power supplied from the first DC power supply. Includes a driving force generation mechanism.

  According to the present invention, it is possible to realize an electric power system capable of performing precharge more securely and safely and a vehicle including the same.

  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 provided with an electric power system according to an embodiment of the present invention.

  Referring to FIG. 1, a vehicle 100 according to an embodiment of the present invention is an electric vehicle configured to be able to travel by a vehicle driving force generated by a motor generator as an example.

  Vehicle 100 includes main battery MB, positive power supply line PL, negative power supply line NL, capacitors C1, C2, system relays SMR1, SMR2, boost converter 12, positive supply line MPL, and negative supply line MNL. , Three-phase inverters 14, 16, bidirectional converter 42, auxiliary battery SB, auxiliary machinery 44, air conditioner inverter 46, air conditioner compressor 48, display unit 50, and control device 2. .

  The main battery MB is a direct current power source configured to be able to charge and discharge direct current power. For example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery, or a plurality of power storage elements such as an electric double layer capacitor are connected in series. Configured. In this embodiment, the output voltage of the main battery MB is 288 V (nominal value). Further, in order to detect the output voltage of the main battery MB, a voltage detection unit 10 connected between both poles of the main battery MB is provided. Then, the voltage detection unit 10 sends the detected output voltage VbH of the main battery MB to the control device 2.

  One end of positive power supply line PL is connected to system relay SMR1, and is configured to be electrically connectable to the positive electrode side of main battery MB via system relay SMR1. Similarly, one end of negative power supply line NL is connected to system relay SMR2, and is configured to be electrically connectable to the negative electrode side of main battery MB via system relay SMR2. Positive power supply line PL and negative power supply line NL are paired to supply power from main battery MB to boost converter 12, bidirectional converter 42 and air conditioner inverter 46. The negative power supply line NL is provided with a current detector 11 for detecting an output current supplied from the main battery. Then, the current detection unit 11 sends the detected output current Ib to the control device 2. In the following description, the positive power supply line PL and the negative power supply line NL are simply referred to as “power supply line pair PL, NL”.

  System relay SMR1 electrically connects or disconnects the positive side of main battery MB and positive power supply line PL in response to system enable signal SE from control device 2. Similarly, system relay SMR2 electrically connects or disconnects the negative side of main battery MB and negative power supply line NL in response to system enable signal SE from control device 2.

  Capacitor C1 is connected between positive power supply line PL and negative power supply line NL, and stores electric charge according to the voltage between both power supply lines, thereby smoothing and stabilizing the line voltage. The capacitor C1 is a capacitor to be charged in the precharge operation, as will be described later. Further, in order to detect the charging voltage of the capacitor C1, a voltage detection unit 18 connected to both ends of the capacitor C1 is provided. Then, the voltage detection unit 18 sends the detected charging voltage VL of the capacitor C1 to the control device 2.

  Boost converter 12 is configured to boost DC power supplied from main battery MB and supply it to three-phase inverters 14 and 16, and to step down DC power regenerated from three-phase inverter 14 or 16. The battery MB can also be returned. Specifically, boost converter 12 is configured by a chopper circuit including transistors Q1 and Q2, diodes D1 and D2, and inductor L1. Boost converter 12 performs switching operations of transistors Q1 and Q2 in accordance with switching command PWCH from control device 2.

  The transistors Q1 and Q2 are connected in series between the positive supply line MPL and the negative supply line MNL, and one end of the inductor L1 is connected to the connection point between them. The transistors Q1 and Q2 are configured by a power semiconductor device, and include, for example, an IGBT (Insulated Gate Bipolar Transistor). Alternatively, a bipolar transistor, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a 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 is connected between a connection point between transistor Q1 and transistor Q2 and positive power supply line PL, and repeatedly accumulates and releases electromagnetic energy by a current generated according to the switching operation of transistors Q1 and Q2. That is, the boost converter 12 realizes a boost operation or a step-down operation by repeatedly storing and releasing electromagnetic energy in the inductor L1.

  Three-phase inverter 14 is connected to boost converter 12 via positive supply line MPL and negative supply line MNL, and performs power conversion between boost converter 12 and motor generator MG1. That is, the three-phase inverter 14 can convert the DC power boosted by the boost converter 12 into three-phase AC power, and can also reversely convert the three-phase AC power supplied from the motor generator MG1 into DC power. Is done.

  Three-phase inverter 14 includes transistors Q3 to Q8 and diodes D3 to D8, and a switching operation is performed for each of transistors Q3 to Q8 in accordance with switching command PWM1 from control device 2. By such a switching operation, three-phase AC power composed of three phase voltages (U-phase voltage, V-phase voltage, and W-phase voltage) is generated. Further, the transistors Q3 to Q8 are also composed of power semiconductor devices, and are made of IGBT as an example. Alternatively, bipolar transistors, MOSFETs or GTOs may be used.

  Similarly, the three-phase inverter 16 is also connected to the boost converter 12 via the positive supply line MPL and the negative supply line MNL, and executes the switching operation according to the switching command PWM2 from the control device 2, thereby Power conversion is performed with motor generator MG2.

  Capacitor C2 is connected between positive supply line MPL and negative supply line MNL, and smoothes DC power transferred between boost converter 12 and three-phase inverters 14 and 16. That is, the capacitor C2 functions as a power buffer. Moreover, in order to detect the charging voltage of the capacitor C2, a voltage detection unit 13 connected to both ends of the capacitor C2 is provided. Then, the voltage detector 13 sends the detected charging voltage VH of the capacitor C2 to the control device 2.

  Motor generator MG1 is supplied with the three-phase AC power generated by three-phase inverter 14 and rotates to generate a vehicle driving force. Similarly, motor generator MG2 is supplied with the three-phase AC power generated by three-phase inverter 16 and is rotationally driven to generate vehicle driving force. Motor generators MG1 and MG2 are, for example, a three-phase AC rotating electric machine including a rotor in which a permanent magnet is embedded. Further, motor generators MG1 and MG2 are mechanically connected to drive wheels via a power split mechanism (not shown) constituted by a planetary gear mechanism or the like, and the generated vehicle drive force is appropriately distributed.

  The auxiliary battery SB is a DC power source configured to be able to charge and discharge DC power, and is composed of a lead storage battery as an example, and its output voltage is designed to be 12 V (nominal value). Further, in order to detect the charge / discharge voltage of the auxiliary battery SB, a voltage detection unit 20 connected between both electrodes of the auxiliary battery SB is provided. Then, voltage detection unit 20 sends detected output voltage VbL of auxiliary battery SB to control device 2.

  In the following description, a power path that can be electrically connected to main battery MB is also referred to as a “high voltage system”, and a power path that is electrically connected to auxiliary battery SB is also referred to as a “low voltage system”.

  The auxiliary machinery 44 is a general term for devices that are electrically connected to the auxiliary battery SB and that are operated by low-voltage DC power supplied from at least one of the bidirectional converter 42 and the auxiliary battery SB. As an example, the auxiliary machinery 44 includes many electric devices mounted on a vehicle such as a headlamp, a winker, a wiper, a power window device, a blower fan, and a car navigation device. Note that at least some of the devices included in the auxiliary machinery 44 stop operating in response to a limit signal LIM from the control device 2 as described later.

  Bidirectional converter 42 is connected between auxiliary battery SB and power supply line pair PL, NL, and is configured to be capable of bidirectional power conversion in accordance with switching command PWCL from control device 2. That is, bidirectional converter 42 can generate low-voltage DC power by stepping down high-voltage DC power supplied from main battery MB via power supply line pair PL, NL, and from auxiliary battery SB. The supplied low-voltage DC power is boosted to generate high-voltage DC power. Furthermore, bidirectional converter 42 sends converter current IDH flowing through the converter to control device 2 in accordance with the power conversion operation (step-up operation or step-down operation). A more detailed configuration of the bidirectional converter 42 will be described below.

FIG. 2 is a schematic configuration diagram showing an aspect of the configuration of the bidirectional converter 42.
Referring to FIG. 2, bidirectional converter 42 according to the embodiment of the present invention includes filter units 62 and 64, high-voltage inverter unit 70, low-voltage inverter unit 72, and transformer 66.

  The filter unit 62 is connected between the power line pair PL, NL (FIG. 1) and the high voltage system inverter unit 70, and mainly includes harmonics included in DC power from the high voltage system inverter unit 70 toward the power line pair PL, NL. Reduce wave components. As an example, the filter part 62 consists of arbitrary low-pass filters.

  The high-voltage inverter unit 70 is connected between the filter unit 62 and the high-voltage side of the transformer 66, and performs a switching operation to generate single-phase AC power from DC power supplied from the high-voltage system via the filter unit 62. Generate. In the state where the switching operation of the high-voltage inverter unit 70 is stopped, the single-phase AC power flowing from the transformer 66 into the high-voltage inverter unit 70 is full-wave rectified and converted into DC power, and then the filter unit 62. To the high-pressure system.

  Specifically, the high-voltage inverter unit 70 includes transistors Q11, Q12, Q13, and Q14 and diodes D11, D12, D13, and D14. The transistors Q11 and Q12 connected in series constitute a first arm circuit, and the transistors Q13 and Q14 connected in series constitute a second arm circuit. Each of the first and second arm circuits outputs a corresponding phase potential. The diodes D11, D12, D13, and D14 are connected in antiparallel with the transistors Q11, Q12, Q13, and Q14, respectively, and allow the current from the transformer 66 to the filter unit 62 to pass therethrough and block the current in the reverse direction. For example, bipolar transistors are used as the transistors Q11 to Q14.

  Similarly, filter unit 64 is connected between auxiliary battery SB (FIG. 1) and low-voltage inverter unit 72, and mainly includes harmonics included in DC power from low-voltage inverter unit 72 toward auxiliary battery SB. Reduce ingredients. As an example, the filter unit 64 includes an arbitrary low-pass filter.

  The low-voltage system inverter unit 72 is connected between the filter unit 64 and the low-voltage side of the transformer 66, and performs a switching operation to generate single-phase AC power from DC power supplied from the low-voltage system via the filter unit 64. Generate. In a state where the switching operation of the low-voltage inverter unit 72 is stopped, the single-phase AC power flowing from the transformer 66 to the low-voltage inverter unit 72 is full-wave rectified and converted into DC power, and then the filter unit 64. To the low pressure system.

  Specifically, the low-voltage inverter unit 72 includes transistors Q21, Q22, Q23, and Q24 and diodes D21, D22, D23, and D24. Since the connection configuration between the elements is similar to that of the above-described high-voltage inverter unit 70, detailed description will not be repeated.

  The transformer 66 transforms (boosts or steps down) the AC power input to one side at a transformation ratio corresponding to the turn ratio, and outputs from the other. In the present embodiment, the turns ratio of the transformer 66 is determined so as to substantially match the voltage ratio between the high voltage system voltage (288V) and the low voltage system voltage (12V).

  Bidirectional converter 42 further includes a current detection unit 68 that detects converter current IDH that flows through the power conversion operation (step-up operation or step-down operation). The current detector 68 may be provided at any position as long as the current value of the current path flowing through the bidirectional converter 42 can be detected. In this embodiment, the current detector 68 is provided on the high voltage side of the transformer 66. Current detection unit 68 then sends detected converter current IDH to control device 2 (FIG. 1).

  The operation of bidirectional converter 42 will be described in detail. During boosting operation, low voltage system inverter unit 72 performs switching operation according to switching command PWCH (FIG. 1) to generate AC power, and high voltage system inverter unit 70 performs switching operation. Stopped. Thereby, the DC power flowing from the low voltage system is converted into AC power by the low voltage system inverter unit 72 and then boosted by the transformer 66. Then, the AC power boosted by the transformer 66 is full-wave rectified by the high-voltage inverter unit 70, and then its harmonic components are reduced by the filter unit 62 and sent to the high-voltage system.

  On the other hand, during the step-down operation, an operation opposite to the above operation is performed. That is, the high voltage system inverter unit 70 performs a switching operation according to the switching command PWCH (FIG. 1) to generate AC power, and the low voltage system inverter unit 72 stops the switching operation. Thus, the DC power flowing from the high voltage system is converted into AC power by the high voltage system inverter unit 70 and then stepped down by the transformer 66. Then, the AC power stepped down by the transformer 66 is full-wave rectified by the low-voltage inverter unit 72, and then its harmonic components are reduced by the filter unit 64 and sent to the low-voltage system.

As described above, the bidirectional converter 42 is configured to be capable of bidirectional power conversion.
Referring to FIG. 1 again, air conditioner inverter 46 is connected between air conditioner compressor 48 and power supply line pair PL, NL, and is supplied from main battery MB via power supply line pair PL, NL. The electric power is converted into AC power by the switching operation of the switching element. The air conditioner inverter 46 supplies the AC power to the air conditioner compressor 48.

  The air-conditioner compressor 48 is a compressor for driving a refrigeration cycle for air-conditioning (air conditioning) the vehicle interior of the vehicle 100. The air-conditioner compressor 48 receives AC power supplied from the air-conditioner inverter 46 and rotates to execute a compression operation.

  The display unit 50 is disposed on an instrument panel or the like located in front of the driver's seat, and lights or displays various information from the control device 2. In particular, the display unit 50 notifies the driver of an abnormality that will be described later.

  The control device 2 is activated in response to an ignition on IGON which is a start command of the vehicle 100 given by the driver's operation, and executes a calculation process related to traveling of the vehicle 100. In particular, when ignition on IGON is applied, control device 2 precharges capacitor C1 using power supplied from auxiliary battery SB in a state where main battery MB and power supply line pair PL, NL are disconnected. Execute. In this precharge, vehicle 100 performs a precharge operation based on charging voltage VL of capacitor C1 detected by voltage detection unit 18 and converter current IDH detected by current detection unit 68 (FIG. 2). . Hereinafter, the precharge operation and the control structure in the control device 2 will be described in detail.

(Precharge operation)
FIG. 3 is a diagram for illustrating the precharge operation according to the embodiment of the present invention.

  FIG. 3A shows a precharge operation in a normal state. On the other hand, FIG. 3B shows a precharge operation when an abnormality occurs.

  Referring to FIG. 3A, control device 2 inactivates system enable signal SE to maintain system relays SMR1 and SMR2 in the off state and controls bidirectional converter 42 so as to execute a boosting operation. To do. Then, a direct current is supplied from the bidirectional converter 42 to the high voltage system. Precharge current Ipr output from bidirectional converter 42 flows through the path of positive power supply line PL, capacitor C1 and negative power supply line NL, and charges capacitor C1. The charging of the capacitor C1 is continued until the charging voltage VL of the capacitor C1 substantially matches the output voltage VbH of the main battery MB. In the conventional technique, when the charging voltage of the capacitor C1 substantially coincides with the output voltage VbH of the main battery MB, it is determined that the precharge operation is completed. In response to the completion determination of the precharge operation, the voltage conversion operation of the bidirectional converter 42 is stopped. Subsequently, by activating system enable signal SE, control device 2 sets system relays SMR1 and SMR2 to an on state, and electrically connects main battery MB to power supply line pair PL and NL. At this time, a state where DC power can be supplied from main battery MB to boost converter 12 and three-phase inverters 14 and 16 (FIG. 1), that is, a state where vehicle 100 can travel is formed.

  During the precharge operation, the boost converter 12 and the air conditioner inverter 46 are maintained in a stopped state, so that the precharge current does not flow to the boost converter 12 or the air conditioner inverter 46.

  On the other hand, referring to FIG. 3B, when a short-circuit failure occurs in transistor Q2 constituting boost converter 12, in addition to precharge current Ipr similar to FIG. As a result, a short-circuit current Is flowing through a path including the transistor Q2 in which the short-circuit failure occurs. Assuming that the short-circuit failure mode (failure mode) of the transistor Q2 is assumed to be a conductive state with a relatively large resistance value, the charging voltage VL of the capacitor C1 is equal to the short-circuit current Is and the transistor Q2 short-circuited. It rises to a voltage value corresponding to the product of the resistance value.

  However, even if the charging voltage VL of the capacitor C1 increases until it substantially matches the output voltage VbH of the main battery MB, it is determined that the precharge operation is completed in a state where a short-circuit fault has occurred in the transistor Q2. The main battery MB cannot be electrically connected to the power line pair PL, NL. When main battery MB is electrically connected to power supply line pair PL, NL, a large short-circuit current is generated from main battery MB to transistor Q2, and main battery MB, system relays SMR1, SMR2, power supply line pair PL, NL, etc. This is because there is a risk of damage.

  Therefore, in the present embodiment, the control device 2 determines the completion of the precharge operation based on the converter current IDH flowing through the bidirectional converter 42 in addition to the charging voltage VL of the capacitor C1. That is, when the capacitor C1 is sufficiently charged at normal time, the converter current IDH becomes almost zero, whereas when an abnormality such as a short-circuit failure occurs, even after the capacitor C1 is fully charged, Since the short-circuit current Is continues to flow, the converter current IDH does not become zero.

  As a specific example, the control device 2 determines that the charging voltage VL of the capacitor C1 is larger than a predetermined voltage value close to the output voltage VbH of the main battery MB, and the converter current IDH of the bidirectional converter 42 is a predetermined current close to zero. Only when the value is smaller than the value, it is determined that the precharge operation is completed. Further, when the state where the converter current IDH of the bidirectional converter 42 is larger than a predetermined current value corresponding to the short-circuit current continues for a time longer than the time when the precharge operation should be completed, the control device 2 fails Is determined to have occurred.

  By adopting such a condition, it is possible to determine the completion of the precharge operation with high accuracy and to avoid erroneously determining that the precharge operation is completed when a short circuit failure occurs.

(Control structure)
FIG. 4 is a functional block diagram relating to the precharge operation according to the embodiment of the present invention. Note that the functional blocks shown in FIG. 4 can be realized by incorporating a circuit corresponding to each block in the control device 2, but in many cases, the program stored in a recording medium or the like is read and the program is stored. It is also realized by executing processing according to the above. The same applies to the following functional blocks.

  Referring to FIG. 4, the control structure of control device 2 includes comparison units 202, 204, 208, logical product unit 206, timer 210, and blocking unit 212. Note that the control structure shown in FIG. 4 is activated after the ignition-on IGON is issued, and the processing is started.

  Comparison unit 202 compares charging voltage VL of capacitor C1 detected by voltage detection unit 18 with threshold value α1. Comparison unit 202 activates output signal SG1 to a high voltage level (hereinafter also simply referred to as “H” level) when charging voltage VL of capacitor C1 is greater than threshold value α1.

  Comparing unit 204 compares converter current IDH detected by current detecting unit 68 with threshold value α2. Comparator 204 activates output signal SG2 to “H” level when converter current IDH is smaller than threshold value α2.

  The logical product unit 206 calculates the logical product of the output signals SG1 and SG2, and issues a system enable signal SE according to the result. That is, at the start of processing when both output signals SG1 and SG2 are maintained at the “L” level, system enable signal SE is also maintained in an inactive state, and system relays SMR1 and SMR2 (FIG. 1) are turned off. Yes. Subsequently, when both output signals SG1 and SG2 are activated to “H” level, AND unit 206 determines that the precharge operation is completed, and activates system enable signal SE. Then, system relays SMR1 and SMR2 are driven to an on state. In this embodiment, the logical product unit 206 includes a timer 206a in order to prevent erroneous determination due to instantaneous noise or the like. The timer 206a activates the system enable signal SE when the state in which both the output signals SG1 and SG2 are at "H" level continues for a predetermined time.

  On the other hand, comparison unit 208 compares converter current IDH detected by current detection unit 68 with threshold value α3. Comparing portion 208 activates output signal SG3 to “H” level when converter current IDH is larger than threshold value α3.

  When the output signal SG3 is activated to the “H” level, the timer 210 starts measuring the duration, and if the measured duration exceeds the threshold value α4, the timer 210 malfunctions. Is determined to have occurred. When it is determined that an abnormality has occurred, the timer 210 issues an abnormality signal FAL1.

  The blocking unit 212 is inserted in the output path of the logical product unit 206, and is configured to be able to electrically block the output path in response to the abnormal signal FAL1. That is, when the abnormal signal FAL1 is generated, the blocking unit 212 blocks the system enable signal SE output from the logical product unit 206, and turns off the system relays SMR1 and SMR2 regardless of the output of the logical product unit 206. maintain.

  Further, the control structure of the control device 2 further includes subtraction units 220 and 222, PI calculation units 224 and 226, modulation units (MOD) 228 and 230, a selection unit 232, and a blocking unit 234. These functional blocks function to control the power conversion operation of bidirectional converter 42 (FIG. 1). That is, bidirectional converter 42 performs a power conversion operation (boost operation) from the low voltage system to the high voltage system during the precharge operation, and after completing the precharge operation, the power conversion operation from the high voltage system to the low voltage system. (Step-down operation) must be performed. Therefore, the subtraction unit 220, the PI calculation unit 224, and the modulation unit 228 generate a switching command for instructing the step-up operation, and the subtraction unit 222, the PI calculation unit 226, and the modulation unit 230 specify the switching command for the step-down operation. Is generated. Then, the selection unit 232 selectively switches the output according to the situation. The details will be described below.

  Subtraction unit 220 subtracts charging voltage VL of capacitor C1 from output voltage VbH of main battery MB, and outputs the deviation to PI calculation unit 224. That is, subtraction unit 220 outputs a voltage deviation when the voltage target of charging voltage VL of capacitor C1 is set to output voltage VbH of main battery MB.

  The PI calculation unit 224 includes at least a proportional element and an integral element, and outputs a value corresponding to the deviation output from the subtraction unit 220 to the modulation unit 228.

  Modulator 228 generates a switching command PWCL for boosting bidirectional converter 42. More specifically, a switching command PWCL for switching the low-voltage inverter unit 72 (FIG. 2) of the bidirectional converter 42 is generated.

On the other hand, subtraction unit 222 subtracts output voltage VbL of auxiliary battery SB from output voltage target VbL ^* of auxiliary battery SB, and outputs the deviation to PI calculation unit 226.

  Similar to the PI operation unit 224, the PI operation unit 226 includes at least a proportional element and an integration element, and outputs a value corresponding to the deviation output from the subtraction unit 222 to the modulation unit (MOD) 230.

  Modulator 230 generates a switching command PWCL for causing bidirectional converter 42 to perform a step-down operation. More specifically, a switching command PWCL for switching the high-voltage inverter unit 70 (FIG. 2) of the bidirectional converter 42 is generated.

  The selection unit 232 selects one of the switching commands PWCL output from the modulation unit 228 and the modulation unit 230 in accordance with the system enable signal SE, and provides the switching command PWCL to the bidirectional converter 42. Specifically, the selection unit 232 gives the switching command PWCL from the modulation unit 228 to the bidirectional converter 42 during the precharge operation, that is, in a state where the system enable signal SE is not issued. Further, the selection unit 232 gives the switching command PWCL from the modulation unit 230 to the bidirectional converter 42 after the precharge operation is completed, that is, in a state where the system enable signal SE is issued.

  The blocking unit 234 is inserted in the output path of the selection unit 232, and is configured to be able to electrically block the output path in response to the abnormality signal FAL1. That is, when the abnormal signal FAL1 is issued, the blocking unit 234 blocks the switching command PWCL output from the selection unit 232, and stops the power conversion operation of the bidirectional converter 42 regardless of the output from the selection unit 232 To maintain.

(Example of precharge operation)
FIG. 5 is a graph schematically showing a time change of each part of the precharge operation at the normal time.

  FIG. 6 is a graph schematically showing a time change of each part of the precharge operation when an abnormality occurs.

  FIG. 5A and FIG. 6A show the power conversion operation of the bidirectional converter 42. FIG. 5B and FIG. 6B show the charging voltage VL of the capacitor C1. FIG. 5C and FIG. 6C show the converter current IDH. FIGS. 5D and 6D show the system enable signal SE.

  Referring to FIG. 5A, when ignition-on IGON is issued, control device 2 causes bidirectional converter 42 to perform a boost operation. Then, as shown in FIGS. 5B and 5C, the capacitor C1 is charged by the converter current IDH output from the bidirectional converter 42, and the charging voltage VL of the capacitor C1 starts to rise. The precharge operation proceeds, and at time t11, charging voltage VL of capacitor C1 reaches output voltage VbH (≈threshold value α1) of main battery MB, and converter current IDH reaches zero (≈threshold value α2). In the present embodiment, the AND unit 206 includes the timer 206a (FIG. 4). Therefore, if this state continues only for the operation time of the timer 206a (between time t11 and time t12), it is determined that the precharge operation is completed. .

  Then, as shown in FIG. 5 (d), the system enable signal SE is activated to electrically connect the main battery MB to the high voltage system, and as shown in FIG. 5 (a), the bidirectional converter. The step-up operation of 42 is stopped, and the operation is switched to the step-down operation in order to charge the auxiliary battery SB.

On the other hand, referring to FIG. 6, the precharge operation when an abnormality occurs will be described below.
Referring to FIG. 6A, when ignition-on IGON is issued, control device 2 causes bidirectional converter 42 to perform a boost operation. Then, as shown in FIGS. 6B and 6C, the capacitor C1 is charged by the converter current IDH output from the bidirectional converter 42, and the charging voltage VL of the capacitor C1 starts to rise. However, for example, if a short-circuit fault has occurred in transistor Q2 (FIG. 1) of boost converter 12, a part of converter current IDH is consumed as a short-circuit current, so compared to the case of FIG. The rising speed of the charging voltage VL of the capacitor C1 is suppressed.

  Further, as shown in FIG. 6C, the converter current IDH continues to flow even if the charging voltage VL of the capacitor C1 increases until it substantially matches the output voltage VbH of the main battery MB. As described above, when the state where converter current IDH is larger than threshold value α3 continues longer than threshold value α4, control device 2 determines that an abnormality has occurred, stops charging capacitor C1 by bidirectional converter 42, and Stop precharge operation. If the control device 2 determines that an abnormality has occurred, the control device 2 notifies the driver or the like of the abnormality via the display unit 50 (FIG. 1).

(Precharge operation procedure)
FIG. 7 is a flowchart showing a processing procedure related to the precharge operation according to the embodiment of the present invention.

  Referring to FIG. 7, control device 2 executes the following process when ignition on IGON is issued.

  Controller 2 generates switching command PWCL for instructing boosting operation to bidirectional converter 42 while maintaining system enable signal SE in the inactive state (step S100). Then, control device 2 determines whether or not charging voltage VL of capacitor C1 detected by voltage detection unit 18 is greater than threshold value α1 (step S102).

  When charging voltage VL of capacitor C1 is greater than threshold value α1 (YES in step S102), control device 2 determines whether or not converter current IDH detected by current detection unit 68 is smaller than threshold value α2. Is determined (step S104). If converter current IDH is smaller than threshold value α2 (YES in step S104), control device 2 determines that the precharge operation is completed (step S106). Note that it may be determined that the precharge operation is completed only when the state of YES in both steps S102 and S104 continues for a predetermined time.

  Thereafter, control device 2 stops the boosting operation in bidirectional converter 42 and stops charging of capacitor C1 (step S108). Then, the control device 2 ends the precharge process.

  On the other hand, when charging voltage VL of capacitor C1 is not larger than threshold value α1 (in the case of NO in step S102) or converter current IDH is not smaller than threshold value α2 (in the case of NO in step S104), Control device 2 determines whether or not converter current IDH detected by current detector 68 is larger than threshold value α3 (step S110). When converter current IDH detected by current detection unit 68 is larger than threshold value α3 (YES in step S110), control device 2 determines whether the state continues longer than threshold value α4. It is determined whether or not (step S112). If it continues longer than threshold value α4 (YES in step S112), control device 2 determines that an abnormality has occurred in the device electrically connected to the high voltage system (step S114). Then, the power conversion operation in bidirectional converter 42 is stopped and connection of main battery MB to the high voltage system is prohibited (step S116). Then, the control device 2 ends the precharge process.

  When converter current IDH detected by current detector 68 is not larger than threshold value α3 (in the case of NO in step S110), or does not continue longer than threshold value α4 (in the case of NO in step S112). The control device 2 repeats the processes in and after step S102 again.

(Abnormality monitoring function in bidirectional converter)
When the precharge operation is completed according to the above-described processing procedure, control device 2 activates system enable signal SE to drive system relays SMR1 and SMR2 to the on state, and main battery MB and power supply line pair PL, NL Are electrically connected. Then, control device 2 causes bi-directional converter 42 to perform a step-down operation so that auxiliary battery SB is charged with the power supplied from main battery MB.

  Here, it is assumed that some failure occurs in the bidirectional converter 42 and the power conversion operation becomes impossible. When such an abnormality occurs in the bidirectional converter 42, the occurrence of the abnormality cannot be detected at an early stage only by monitoring the output voltage VbL of the auxiliary battery SB detected by the voltage detection unit 20 (FIG. 1). That is, since auxiliary battery SB is a power storage element, even if charging by bidirectional converter 42 is interrupted, output voltage VbL does not immediately decrease. Therefore, it is considered that the charging power remaining in the auxiliary battery SB is very small when the output voltage VbL falls below a predetermined lower limit voltage value after the charging power from the bidirectional converter 42 is interrupted. It is done.

  FIG. 8 is a graph schematically showing a time change when the power conversion operation in the bidirectional converter 42 becomes impossible.

  FIG. 8A shows the converter current IDH. FIG. 8B shows the output voltage VbL of the auxiliary battery SB.

  Referring to FIG. 8A, as an example, when an abnormality occurs in bidirectional converter 42 at time t21, no current can be output from bidirectional converter 42, and converter current IDH becomes zero. On the other hand, since auxiliary battery SB is stored in advance, output voltage VbL does not decrease rapidly but decreases with a predetermined time constant. Therefore, in the configuration in which the occurrence of abnormality in the bidirectional converter 42 is determined based on whether or not the output voltage VbL is lower than the voltage V2, the occurrence of abnormality in the bidirectional converter 42 cannot be detected until time t22. As a result, the charging power remaining in the auxiliary battery SB is very small at the time when the occurrence of an abnormality in the bidirectional converter 42 is detected, and there is a possibility that even the evacuation operation cannot be performed. Therefore, in this embodiment, when the bidirectional converter 42 charges the auxiliary battery SB, the occurrence of abnormality in the bidirectional converter 42 is detected based on the converter current IDH.

  FIG. 9 is a functional block diagram relating to monitoring of occurrence of abnormality in bidirectional converter 42 according to the embodiment of the present invention.

  Referring to FIG. 9, the control structure of control device 2 includes a comparison unit 240. Note that the control structure shown in FIG. 9 is activated after the system enable signal SE is issued, and the processing is started.

  Comparison unit 240 compares converter current IDH detected by current detection unit 68 (FIG. 2) with threshold value α5. Then, when converter current IDH is smaller than threshold value α5, comparison unit 240 determines that an abnormality has occurred in bidirectional converter 42 and issues abnormality signal FAL2. In response to the abnormality signal FAL2, for example, on the display unit 50 (FIG. 1), a lamp indicating the occurrence of the “failure” of the bidirectional converter 42 is turned on. Further, a diagnostic code indicating the occurrence of the abnormality may be issued.

  The threshold value α5 may be a predetermined fixed value or a variable value corresponding to the power consumed by the auxiliary machinery 44.

  FIG. 10 is a flowchart showing a processing procedure relating to monitoring of occurrence of abnormality in bidirectional converter 42 according to the embodiment of the present invention.

  Referring to FIG. 10, when determining that the precharge operation is completed, control device 2 executes the following processing.

  Control device 2 activates system enable signal SE and drives system relays SMR1 and SMR2 to the ON state (step S200). Then, main battery MB is electrically connected to power supply line pair PL, NL. Then, control device 2 generates switching command PWCL for instructing step-down operation to bidirectional converter 42 such that auxiliary battery SB is charged with the power supplied from main battery MB (step S202).

  Subsequently, control device 2 determines whether or not converter current IDH detected by current detection unit 68 is smaller than threshold value α5 (step S204). When converter current IDH is not smaller than threshold value α5 (NO in step S204), control device 2 repeats steps S202 and S204 described above.

  On the other hand, if converter current IDH is smaller than threshold value α5 (YES in step S204), control device 2 determines that an abnormality has occurred in bidirectional converter 42 (step S206). And the control apparatus 2 emits the abnormality signal FAL2 (step S208), and complete | finishes a process.

(Power management function for auxiliary equipment)
In addition to the function of monitoring the occurrence of an abnormality in the bidirectional converter 42 as described above, an overload state of the bidirectional converter 42 may be avoided and a failure may be prevented.

  A vehicle user often adds various in-vehicle devices (for example, a car navigation device) after purchasing the vehicle. Since such an in-vehicle device uses the electric power of the auxiliary machinery 44, the in-vehicle device added later is used even though the rated value of the bidirectional converter 42 is designed with a considerable margin at the time of design. The increase in power consumption by the device may exceed that margin. Therefore, in this embodiment, power management is performed for the auxiliary machinery 44 so that the power supplied from the bidirectional converter 42 to the auxiliary machinery 44 does not exceed the rated value based on the converter current IDH.

  FIG. 11 is a functional block diagram relating to power management for auxiliary machinery 44 according to the embodiment of the present invention.

  Referring to FIG. 11, the control structure of control device 2 includes a subtracting unit 250 and a load limiting unit 252. The control structure shown in FIG. 11 is activated after the system enable signal SE is issued, and the processing is started.

  The subtractor 250 subtracts the converter current IDH detected by the current detector 68 from the rated value (rated current) of the bidirectional converter 42 to calculate a margin. Then, the subtraction unit 250 outputs the calculated margin amount to the load limiting unit 252.

  The load limiting unit 252 generates a limiting signal LIM for limiting the power consumption in the auxiliary machinery 44 based on the margin amount received from the subtracting unit 250. The limit signal LIM may be any signal as long as it can limit the power consumption in the auxiliary equipment 44. As an example, after the limit signal LIM is issued, no further power is supplied. It may be configured. Further, the supply route to the auxiliary machinery 44 may be divided according to the importance, and the power supply to the supply route having a relatively low importance may be cut off by the limit signal LIM.

  Since the voltage value of the DC power supplied from bidirectional converter 42 to auxiliary battery SB is substantially constant, converter current IDH shows a value proportional to the DC power supplied from bidirectional converter 42. Therefore, power management is possible based on converter current IDH.

  FIG. 12 is a graph schematically showing a time change in the power management function for the auxiliary machinery 44.

  FIG. 12A shows the converter current IDH. FIG. 12B shows a margin in the bidirectional converter 42. FIG. 12C shows the limit signal LIM.

  Referring to FIG. 12A, as an example, when the power consumption in auxiliary equipment 44 gradually increases during operation of vehicle 100 and converter current IDH approaches the rated value of bidirectional converter 42, FIG. As shown in (b), the margin is gradually reduced. Therefore, as an example, when the margin is less than the threshold value α6, the load limiter 252 issues a limit signal LIM as shown in FIG. 12 (c) to limit the power consumption in the auxiliary equipment 44.

  By executing such processing, it is possible to prevent the bidirectional converter 42 from being overloaded and to prevent failure.

  FIG. 13 is a flowchart showing a processing procedure related to power management for auxiliary machinery 44 according to the embodiment of the present invention.

  Referring to FIG. 13, control device 2 executes the following process when system enable signal SE is activated.

  First, control device 2 determines whether or not bidirectional converter 42 is in a step-down operation so as to charge auxiliary battery SB with the power supplied from main battery MB (step S300). If bi-directional converter 42 is not in the step-down operation (NO in step S300), control device 2 returns to the first process of this flowchart.

  When bidirectional converter 42 is performing a step-down operation (YES in step S300), control device 2 determines whether converter current IDH detected by current detection unit 68 with respect to the rated value of bidirectional converter 42 or not. A margin amount is calculated (step S302). Then, the control device 2 determines whether or not the calculated surplus flow rate is smaller than a predetermined threshold value α6 (step S304). If the calculated margin is smaller than threshold value α6 (YES in step S304), control device 2 determines that the power consumption in auxiliary machinery 44 should be limited (step S306). . Then, the control device 2 issues a limit signal LIM (step S308).

  On the other hand, when converter current IDH is not smaller than threshold value α6 (NO in step S304), control device 2 cancels limit signal LIM (step S310).

And the control apparatus 2 returns to the first process of this flowchart.
In the embodiment of the present invention, main battery MB corresponds to “first DC power supply”, boost converter 12, motor generators MG1 and MG2, and air conditioner inverter 46 correspond to “first load group”, and capacitors C1 corresponds to “capacitor”, system relays SMR1 and SMR2 correspond to “relay part”, auxiliary battery SB corresponds to “second DC power supply”, and bidirectional converter 42 becomes “bidirectional converter”. The air conditioner inverter 46 corresponds to the “inverter device”, the auxiliary machinery 44 corresponds to the “second load group”, and the three-phase inverters 14 and 16 and the motor generators MG1 and MG2 correspond to the “driving force generation mechanism”. Is equivalent to. Further, the voltage detection unit 18 implements “voltage detection unit”, the current detection unit 68 implements “current detection unit”, and the control device 2 implements “precharge unit”. Further, the comparison unit 202 implements a “first comparison unit”, the comparison unit 204 implements a “second comparison unit”, the comparison unit 208 implements a “third comparison unit”, and the comparison unit 240. Realizes “fourth comparison means” and “third determination means”, logical product unit 206 realizes “first determination means”, timer 210 realizes “second determination means”, The selection unit 232 realizes a “stop unit”, the blocking units 212 and 234 implement an “abnormal treatment unit”, and the subtraction unit 220, the PI calculation unit 224, and the modulation unit 228 implement a “first control unit”. The subtraction unit 222, the PI calculation unit 226, and the modulation unit 230 realize a “second control unit”, the subtraction unit 250 implements a “calculation unit”, and the load limiting unit 252 implements a “limiting unit”.

  According to the embodiment of the present invention, when the capacitor C1 connected between the power supply line pair PL, NL is precharged, the charging state is determined based on the charging voltage VL of the capacitor C1, and the bidirectional converter 42 is used. Based on the converter current IDH supplied from the power supply line PL to NL, it can be determined whether or not the current that should be supplied to the capacitor C1 is supplied. Therefore, for example, when a short-circuit failure or the like occurs in boost converter 12, the current value increases by a short-circuit current due to the short-circuit failure as compared with the current value originally supplied to capacitor C1. Abnormalities such as short-circuit faults can be detected. Therefore, the precharge can be executed more reliably and safely.

  In addition, according to the embodiment of the present invention, when charging power is supplied from bidirectional converter 42 to auxiliary battery SB, occurrence of abnormality in bidirectional converter 42 is monitored based on converter current IDH. As a result, even if the output of the bidirectional converter 42 to which the auxiliary battery SB, which is a storage element, is connected, if an abnormality that disables the power conversion operation occurs, it is immediately detected. Can do. Therefore, it is possible to execute appropriate measures such as a evacuation operation while the charge amount of the auxiliary battery SB is sufficiently present.

  Furthermore, according to the embodiment of the present invention, when the current supplied from bidirectional converter 42 to auxiliary machinery 44 increases and the margin for the rated value decreases, the power consumption in auxiliary machinery 44 is limited. . Thereby, the overload state of the bidirectional converter 42 can be avoided and a failure can be prevented.

  In the above-described embodiment, the configuration including the processing related to the precharge operation, the monitoring processing for occurrence of abnormality in the bidirectional converter, and the power management processing for the auxiliary devices is illustrated, but each processing is incorporated independently of each other. Can be executed.

  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 provided with the electric power system according to embodiment of this invention. It is a schematic block diagram which shows the one aspect | mode of a structure of a bidirectional | two-way converter. It is a diagram for illustrating a precharge operation according to the embodiment of the present invention. FIG. 7 is a functional block diagram relating to a precharge operation according to an embodiment of the present invention. It is a graph which shows typically a time change of each part of precharge operation at the time of normal. It is a graph which shows typically the time change of each part of precharge operation at the time of abnormality occurrence. It is a flowchart which shows the process sequence which concerns on the pre-charge operation | movement according to embodiment of this invention. It is a graph which shows typically a time change when the power conversion operation in a bidirectional converter becomes impossible. It is a functional block diagram concerning monitoring of occurrence of abnormality in the bidirectional converter according to the embodiment of the present invention. It is a flowchart which shows the process sequence which concerns on the monitoring of abnormality generation in the bidirectional | two-way converter according to embodiment of this invention. It is a functional block diagram which concerns on the electric power management about the auxiliary machines according to embodiment of this invention. It is a graph which shows typically the time change in the power management function about auxiliary machinery. It is a flowchart which shows the process sequence which concerns on the electric power management about the auxiliary machines according to embodiment of this invention.

Explanation of symbols

  2 Control device 10, 18, 20 Voltage detection unit, 11, 68 Current detection unit, 12 Boost converter, 13 Voltage detection unit, 14, 16 Three-phase inverter, 42 Bidirectional converter, 44 Auxiliaries, 46 Air conditioner inverter , 48 Compressor for air conditioner, 50 Display unit, 62, 64 Filter unit, 66 Transformer, 70 High-voltage inverter unit, 72 Low-voltage inverter unit, 100 Vehicle, 202, 204, 208, 240 Comparison unit, 206 Logical product unit, 206a , 210 timer, 212, 234 blocking unit, 220, 222, 250 subtraction unit, 224, 226 PI calculation unit, 228, 230 modulation unit, 232 selection unit, 252 load limiting unit, C1, C2 capacitors, D1-D8, D11 ~ D14, D21 ~ D24 Diode, L1 Inductor, MB Main battery, MG1, MG2 Motor generator, MNL negative supply line, MPL positive supply line, NL negative power supply line, PL positive power supply line, Q1-Q8, Q11-Q14, Q21-Q24 Transistor, SB Auxiliary battery, SMR1, SMR2 System relay.

Claims (9)

A first DC power supply;
A pair of power lines for supplying DC power to the first load group;
A capacitor connected between the power supply line pair;
A relay unit connected between the first DC power source and the power line pair;
A second DC power source;
A bidirectional converter connected between the second DC power source and the power line pair and capable of bidirectional power conversion;
Voltage detecting means for detecting a charging voltage of the capacitor;
Current detecting means for detecting a current flowing through the bidirectional converter;
Precharge means for charging the capacitor using power supplied from the second DC power supply in a state where the first DC power supply and the power supply line pair are electrically disconnected by the relay unit;
The precharge unit controls a precharge operation based on a charging voltage value detected by the voltage detection unit and a current value detected by the current detection unit. The precharge means includes
First comparison means for comparing a charging voltage value detected by the voltage detection means with a first threshold value;
Second comparison means for comparing a current value detected by the current detection means with a second threshold value;
First determination means for determining that the precharge operation is completed when the charging voltage value is larger than the first threshold value and the current value is smaller than the second threshold value;
2. The power system according to claim 1, further comprising: a stopping unit that stops charging of the capacitor by the bidirectional converter when the first determining unit determines that the precharge operation is completed. The precharge means includes
Third comparison means for comparing a current value detected by the current detection means with a third threshold value;
When the duration of the state where the current value is larger than the third threshold is measured and the duration is longer than the fourth threshold, an abnormality occurs in a portion electrically connected to the power line pair The power system according to claim 1, further comprising: a second determination unit that determines   The precharge means stops the power conversion operation in the bidirectional converter when the second determination means determines that an abnormality has occurred, and electrically connects the first DC power supply and the power supply line pair. The power system according to claim 3, further comprising abnormality treatment means for prohibiting connection.   The precharge means includes first control means for controlling a power conversion operation of the bidirectional converter so that a charge voltage detected by the voltage detection means substantially matches an output voltage of the first DC power supply. Furthermore, the electric power system of any one of Claims 1-4 further included. The first load group includes an inverter device that converts supply power from the first DC power source into AC power by a switching operation of a switching element;
The power system according to claim 1, wherein the inverter device is maintained in a stopped state during the precharge. The power system is
After the completion of the precharge operation, connection means for electrically connecting the first DC power supply and the power supply line pair by the relay unit;
After both the first DC power supply and the power supply line pair are electrically connected by the connecting means, the both DC power supplies are charged with the power supplied from the first DC power supply. Second control means for controlling the power conversion operation of the bidirectional converter;
Fourth comparison means for comparing a current value detected by the current detection means with a fifth threshold value;
The electric power system according to any one of claims 1 to 6, further comprising third determination means for determining that an abnormality has occurred in the bidirectional converter when the current value is smaller than the fifth threshold value. . The power system is
A second load group electrically connected to the second DC power source;
Calculating means for calculating a margin between the current value detected by the current detecting means with respect to the rated value of the bidirectional converter;
The power system according to any one of claims 1 to 7, further comprising a limiting unit that limits power consumption in the second load group based on a margin amount calculated by the calculation unit. A vehicle comprising the power system according to any one of claims 1 to 8,
The first load group includes a driving force generation mechanism configured to generate a vehicle driving force by electric power supplied from the first DC power source.

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