JP2015167444A - Protection system of feeder circuit for electric propulsion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection system of a feeder circuit for an electric propulsion device, capable of avoiding power feeding stop of the whole auxiliary machine feeder circuit when a short-circuit fault occurs at the terminal of the auxiliary machine feeder circuit, by blocking only an individual auxiliary machine feeder circuit in which the short-circuit fault has occurred.SOLUTION: A feeder circuit for an electric propulsion device comprising: a main feeder circuit for feeding power to a propulsion motor from a power source with a battery; and an auxiliary machine feeder circuit having individual auxiliary machine feeder circuits for feeding power to a plurality of auxiliary machines and which are branched for each of the auxiliary machines. In the auxiliary machine feeding circuit, an upstream-side overcurrent protection unit is provided on a source flow passage on the upstream side of the individual auxiliary machine feeder circuits of the auxiliary machine feeder circuit, a downstream-side overcurrent protection unit is provided in each of the downstream-side individual auxiliary machine feeding circuits, and a high-speed current-limiting unit is serially connected to each downstream-side overcurrent protection unit. When a short-circuit fault occurs at the terminal of the individual auxiliary machine feeder circuit, a short-circuit current is limited by the high-speed current-limiting unit to a current equal to or below a breaking current setting value of the upstream-side overcurrent protection unit, thereby the current is cut-off more quickly by the downstream-side overcurrent protection unit than the upstream-side overcurrent protection unit.

Description

  The present invention relates to a protection method for protecting a power feeding circuit in an electric propulsion apparatus using a battery such as an electric vehicle or an electric propulsion ship from an overcurrent such as a short circuit current.

  As a power supply circuit protection device in an electric propulsion device using a battery as a power source, the one shown in Patent Document 1 is known, and its configuration is shown in FIG.

  The power supply circuit of the electric propulsion device in FIG. 11 includes a main power supply circuit ML serving as a power supply path from the battery Bp to the propulsion motor M and a charging path from the generator G to the battery, and from the battery Bp or the generator G to the electric propulsion device. The auxiliary power supply circuit AL is configured to supply power to a large number of necessary auxiliary equipment S.

  The main power supply circuit ML includes, as protective devices, a main power supply circuit switch DSM, a main power supply circuit overcurrent protection device UFM that cuts off a current limit of a fuse, and a circuit breaker CBM as power supply circuits from the generator G. Are provided with an overcurrent protection device UFG capable of interrupting current limiting such as a circuit breaker CBG and a fuse.

  In addition, it is an indispensable important element for the safe operation of the electric propulsion device to stably supply electric power to various auxiliary devices S1 to Sn. For this purpose, the auxiliary power supply circuit AL is provided with a common auxiliary power supply circuit switch DSA and an upstream overcurrent protection device UFA capable of interrupting current limiting such as a fuse. Circuit breakers CBS1 to CBSn are provided in the individual auxiliary power supply circuits ALS1 to ALSn that branch from the auxiliary power supply circuit AL and supply power to the plurality of individual auxiliary devices S1 to Sn, respectively. When a short circuit accident or the like occurs and the circuit current becomes excessive, these protective devices cut off these currents and protect the circuit and the load devices such as the propulsion motor M and the auxiliary device S from the excessive current.

  As shown in the equivalent circuit shown in FIG. 11, the electric circuit inductances LBp, L1, LSi, and electric circuit are connected to the electric circuit from the power source Bp constituted by the battery of the electric power supply circuit to the terminal (Pi point) of the individual auxiliary power supply circuit. Resistors RBp, R1, RSi are distributed. The sum total of the circuit inductances LBp, L1, and LSi is called a total circuit inductance LΣp0 of the entire power supply path, and the sum of the circuit resistances RBp, R1, and RSi is called a total circuit resistance RΣp0.

  In the conventional power supply circuit, since the battery power source Bp is composed of a lead battery having large characteristics of the internal inductance LBp and the internal resistance RBp, the total circuit inductance LΣp0 and the total circuit resistance RΣp0 to the end of the individual auxiliary power supply circuit are large. Become. As a result, when a short-circuit accident occurs at the end of the auxiliary power supply circuit to which the auxiliary equipment Si is connected, the short-circuit current is kept relatively small and the total circuit time constant TΣp0 (= LΣp0 ÷ RΣp0) is also relatively large. The rate of increase in short circuit current can be kept small.

  Here, the breaking current set value Is of the circuit breaker CBSi for the individual auxiliary power supply circuit ALi is set to 300A, and the breaking current set value IAs of the upstream overcurrent protection device UFA of the auxiliary power supply circuit AL is set to 3000A. Yes. In such an auxiliary power feeding circuit AL, when a short circuit accident occurs at the terminal Pi point, the short circuit current rises relatively slowly as indicated by a characteristic line A in FIG. The circuit breaker CBSi for the individual auxiliary power feeder circuit Si detects this short-circuit current at the point A0 when the short-circuit current reaches the cut-off current set value Is (= 300 A), starts the cut-off operation, and starts a mechanical operation delay time ( The switching contact is opened at point A1 after 13 ms) to limit (cut off) the accident current, and the interruption is completed at point A2 where the current is completely zero.

  At this time, the current (1800A) at the breaking start point A1 of the circuit breaker CBSi for wiring does not reach the breaking current set value AU (3000A) of the upstream overcurrent protection device UFA of the auxiliary power feeding circuit AL. The upstream overcurrent protection device UFA does not operate. That is, since the protection coordination between the upstream protection device and the downstream protection device is secured, when a short circuit accident occurs on the downstream side of the power supply circuit AL, the individual auxiliary machine power supply circuit in which the short circuit accident has occurred Only the circuit breaker CBSi for wiring performs the operation for interrupting the short-circuit fault current, and the upstream protection device UFA does not perform the operation for interrupting. Therefore, the power supply to the remaining healthy individual auxiliary power supply circuit can be continued without stopping. it can.

  However, in recent years, in an electric propulsion apparatus using a battery as a power source such as a ship, a lithium ion battery has been adopted instead of a conventional lead battery as the propulsion capacity increases.

  A power source using a lithium ion battery has high performance and can have a large capacity, but the short circuit current can be limited when a short circuit accident occurs because the internal resistance and circuit inductance of the battery are extremely small. This is enormous. For this reason, in a power supply circuit using a lithium ion battery as a power source, when a short-circuit accident occurs, a conventional overcurrent protection device such as a circuit breaker, a fuse, or the like has insufficient interruption capability, and an accident current There is a concern that problems may occur that cannot be safely and reliably blocked.

  In addition, the short-circuit fault current is not only enormous, but also the current rise rate is fast, so when a short-circuit fault occurs at the end of the auxiliary power supply circuit, the downstream protection device, that is, the individual auxiliary power supply circuit Before the interrupting operation of the inserted circuit breaker CBSi is completed, the overcurrent protection device UFA inserted in the upstream common auxiliary power supply circuit operates to interrupt the power supply of the entire auxiliary power supply circuit. This makes it impossible to operate all the auxiliary equipment, and seriously impedes the safe operation of the electric propulsion device.

Japanese Patent Laying-Open No. 2005-086891

  In this way, in the power feeding circuit that is fed from the power source constituted by the lithium ion battery in the conventional electric propulsion device, the short circuit current rises quickly, so the upstream overcurrent protection device provided upstream of the individual auxiliary power feeding circuit And the downstream overcurrent protection device such as the circuit breaker for wiring provided in each individual auxiliary power supply circuit, and the downstream overcurrent protection device when a short circuit accident occurs at the end of the auxiliary power supply circuit There is a problem in that the upstream protection device shuts down before the power is shut off and power supply to the entire auxiliary power feeding circuit is stopped.

  In order to solve such a problem, the present invention enables protection coordination between the upstream side overcurrent protection device and the downstream side overcurrent protection device of the auxiliary power feeding circuit in the electric propulsion device, so that a short-circuit accident can cause the auxiliary power feeding. When this occurs at the end of the circuit, only the individual auxiliary machine power supply circuit where the short circuit accident occurred is shut off, and the upstream overcurrent protection device is not operated to avoid the entire auxiliary machine power supply circuit from being stopped. It is an object of the present invention to provide a power feeding circuit protection method that can be used.

  In order to solve the above problems, the present invention provides a main power feeding circuit for feeding power to a propulsion motor from a power source constituted by a battery having a small internal resistance and electric circuit inductance like a power source constituted by a lithium ion battery, A power supply circuit for an electric propulsion device comprising an auxiliary power supply circuit having an individual auxiliary power supply circuit branched for each auxiliary device in order to supply power to a plurality of auxiliary devices from a power supply. An upstream overcurrent protection device that protects the auxiliary power supply circuit from overcurrent in the upstream source flow path of the individual auxiliary power supply circuit, and an individual auxiliary power supply circuit in each individual auxiliary power supply circuit on the downstream side Is provided with a downstream overcurrent protection device that protects against overcurrent, and a high-speed current limiting device is connected in series to each of the downstream overcurrent protection devices of the individual auxiliary power supply circuit, and a short circuit accident occurs in the individual auxiliary power supply circuit. When it occurs The individual auxiliary power supply in which the short-circuit fault occurs earlier than the upstream overcurrent protection device by limiting the short-circuit current to a current equal to or lower than the cutoff current set value of the upstream overcurrent protection device by the high-speed current limiting device. The circuit is cut off by an overcurrent protection device on the downstream side of the circuit, and the accident circuit is disconnected.

  In the present invention, the high-speed current limiting device can be configured by connecting in parallel a current-limiting resistor and high-speed switch means that closes at a normal current and opens at a high speed when an overcurrent occurs. As the high-speed switch means, a high-speed fuse or a semiconductor switch device can be used.

  Further, in the present invention, a current limiting reactor can be inserted in series in each of the auxiliary power feeding circuit or the individual auxiliary power feeding circuit.

  According to the present invention, the upstream overcurrent protection device is provided in the auxiliary power supply circuit of the electric propulsion device, the downstream overcurrent protection device is provided in the individual auxiliary power supply circuit, and the high speed current limiting device is connected in series thereto. Therefore, when a short-circuit accident occurs at the end of the individual auxiliary power supply circuit, the short-circuit current is limited by the current-limiting device to a current that is less than or equal to the cutoff set current value of the upstream-side overcurrent protection device. By shutting down the downstream overcurrent protection device earlier than the protection device, only the individual auxiliary power supply circuit that has caused the short-circuit accident can be disconnected, so the upstream overcurrent protection device of the auxiliary power supply circuit cannot operate. Therefore, the safety and reliability of the electric propulsion device can be improved by preventing the power failure of the auxiliary power supply circuit.

It is a block diagram of the electric power feeding circuit of the electric propulsion apparatus which shows 1st Example of this invention. FIG. 3 is an equivalent circuit diagram of an individual auxiliary machine power supply circuit of the electric propulsion device according to the first embodiment of the present invention. It is a block diagram of the electric power feeding circuit of the electric propulsion apparatus which shows the 2nd Example of this invention. FIG. 6 is an equivalent circuit diagram of an individual auxiliary machine power supply circuit of an electric propulsion device according to a second embodiment of the present invention. It is a block diagram of the current limiting device in 2nd Example of this invention. It is a block diagram of the electric power feeding circuit of the electric propulsion apparatus which shows the 3rd Example of this invention. It is an equivalent circuit diagram of the individual auxiliary machine electric power feeding circuit of the electric propulsion device of the 3rd example of this invention. It is a current interruption characteristic figure used for operation explanation of this invention. It is a block diagram of the electric power feeding circuit of the electric propulsion apparatus which shows the 4th Example of this invention. It is an equivalent circuit diagram of the individual auxiliary machine electric power feeding circuit of the electric propulsion apparatus of the 4th Example of this invention. It is a block diagram of the electric power feeding circuit of the conventional electric propulsion apparatus. It is an equivalent circuit diagram of the individual auxiliary machine power supply circuit of the conventional electric propulsion device.

  Embodiments of the present invention will be described with reference to the embodiments shown in the drawings.

  FIG. 1 shows a power supply circuit according to a first embodiment of the present invention.

  In the power supply circuit according to the first embodiment shown in FIG. 1, the power supply Br has an extremely small internal resistance RBr as compared with a conventional lead battery, for example, as a power supply constituted by a lithium ion battery, and also has an electric circuit inductance LBr. It is a power source composed of a battery having small characteristics.

  The power supply Br is connected to a main power supply circuit ML that supplies power to the propulsion motor M and an auxiliary power supply circuit AL that includes individual auxiliary power supply circuits ALS1 to ALSn that supply power to a plurality of auxiliary devices S1 to Sn. A switch DSM that opens and closes the circuit, a high-speed fuse UFM as an overcurrent protection device, and a circuit breaker CBM are inserted in series in the main power supply circuit ML, thereby protecting the main power supply circuit ML from overcurrent. A generator G is also connected to the main power supply circuit ML via a circuit breaker CBG and a high-speed fuse UFG in order to charge the battery of the power supply Br.

  In addition, an auxiliary switch DSA and a high-speed fuse UFA as an upstream overcurrent protection device are inserted in series into the auxiliary power supply circuit AL for supplying power to the plurality of auxiliary devices S1 to Sn. The auxiliary power supply circuits ALS1 to ALSn that individually supply power to a plurality of auxiliary devices S1 to Sn branched from the auxiliary power supply circuit AL include circuit breakers CBS1 to CBSn and current limiting devices, respectively. A downstream overcurrent protection device configured by connecting CL1 to CLn in series is inserted.

  The current limiting devices CL1 to CLn are configured by connecting high speed fuses FE1 to FEn in parallel with current limiting resistors RE1 to REn, respectively. In the current limiting devices CL1 to CLn, the high speed fuses FE1 to FEn are in a connected (closed) state in a state where a normal load current flows through the individual auxiliary power supply circuits ALS1 to ALSn, so that the current limiting resistors FE1 to FEn are Short-circuited by the high-speed fuses FE1 to FEn, no load current flows through the current limiting resistors RE1 to REn. For this reason, when a normal current is supplied to the individual auxiliary machine power supply circuits ALS1 to ALSn, an energization loss due to the current limiting resistance does not occur.

  In the first embodiment, the upstream overcurrent protection device UFA of the auxiliary power supply circuit AL and the cutoff current set values IAs and Is of the downstream circuit breaker CBSi are 3000 A and It is set to 300A.

  When an excessive current such as a short circuit current flows through the individual auxiliary power supply circuits ALS1 to ALSn, the high speed fuses FE1 to FEn of the current limiting devices CL1 to CLn are set to blow at about 2000A. When the high-speed fuses FE1 to FEn are blown and opened due to the short-circuit current, the short-circuit current is commutated to the current-limiting resistors RE1 to REn to limit the current, and is less than the cut-off set current value of the high-speed fuse UFA as the upstream overcurrent protection device Moreover, the current can be cut off by the circuit breaker CBSi for wiring in the individual auxiliary power feeding circuit.

  For example, if a short circuit accident occurs at the input point P1 of the auxiliary device S1 that is the terminal of the individual auxiliary power supply circuit ALS1 of the power supply circuit of FIG. 1, a short circuit accident current flows through this circuit. Since the high-speed fuse UF1 of the current flow device CL1 is blown first and opens, the short-circuit current is commutated to the current-limiting resistor RE1, and the current-breaking short-circuit current is safely interrupted by the wiring breaker CB1. .

  FIG. 2 shows an equivalent circuit of one individual auxiliary machine power supply circuit ALSi in the power supply circuit of the first embodiment shown in FIG.

  The internal resistance and electric circuit inductance of the power supply Br indicated by RBr and LBr in FIG. 2 are constituted by a battery having a low internal resistance such as a lithium ion battery and a small electric circuit inductance, so that the conventional resistance shown in FIG. It becomes significantly smaller than the internal resistance RBp and the circuit inductance LBp of the power source Bp formed of a lead battery. The auxiliary power supply circuit AL including the upstream overcurrent protection device UFA and the individual auxiliary power supply circuit ALSi including the circuit breaker CBSi have the same circuit resistance RA, circuit inductance LA, and circuit resistance as the conventional power supply circuit, respectively. RSi and circuit inductance LSi are included. The current limiting device CLi provided in the individual auxiliary power supply circuit ALSi is equivalent to a high-speed fuse FEi composed of a series circuit of a normally closed contact Fei, an internal resistance RFi and an internal inductance LFi, as shown in FIG. It is shown in a parallel circuit with a current limiting resistor REi having a resistor Rei.

  For this reason, the total circuit resistance RΣa1 in the normal state (the state where the high-speed fuse of the current limiting device is not blown) from the power supply Br to the output terminal Ai of one individual auxiliary machine power supply circuit ALSi in this equivalent circuit is RΣa1 = RBr + RA + RFi, and the total circuit inductance LΣa1 is LΣa1 = LRr + LA + LFi. However, since the internal resistance RBr and the circuit inductance LBr of the power supply Br are originally extremely small, they are significantly smaller than those in the conventional power supply circuit.

  Further, the internal resistance RFi of the current limiting device CLi of the individual auxiliary power feeding circuit ALSi becomes the resistance value Rei of the current limiting resistance REi when the high-speed fuse FEi is melted due to a short circuit accident. At this time, the internal resistance RBr of the power supply Br Can be compensated for and can be made equal to or larger than the total circuit resistance RΣp0 of the conventional power supply circuit, but the total circuit inductance LΣp1 remains smaller than the total circuit inductance LΣp0 of the conventional power supply circuit. .

  As a result, when a short circuit accident occurs at the Pi point at the end of the individual auxiliary power supply circuit ALSi, as shown by the characteristic line B in FIG. 8, it rises at a faster speed than the conventional short circuit current indicated by the characteristic line A. Short circuit current flows. The circuit breaker CBSi for the wiring of the individual auxiliary power supply circuit ALSi reaches the breaking current set value Is (= 300 A) of the short-circuit current at the point B0 on the characteristic line B in FIG. 8, and detects this to start the breaking operation. Due to the mechanical delay, the shut-off operation is not started immediately.

  On the other hand, the high-speed fuse FEi of the current limiting device CLi starts a breaking operation (melting) at a point B1 exceeding the breaking current set value (2000A), and breaks while short-circuiting the current. When the cut-off operation (melting) is completely completed at the point B2 and the short-circuit current is commutated to the current-limiting resistor REi, the short-circuit current is limited to the current (1500 A) determined by the resistance value Rei of the current-limiting resistor REi. It is. When the time corresponding to the circuit breaker CBSi operation delay time (13 ms) elapses from point B0, the circuit breaker CBSi opens the switching contact at the point B3 and starts the interruption of the fault current, and the circuit breaks at the point B4. Complete.

  As described above, in the first embodiment, when a short circuit accident occurs at the end of the individual auxiliary power supply circuit ALSi, the short circuit current is caused by the current limiting device CLi, and the breaking current set value of the high-speed fuse UFA as the upstream overcurrent protection device. (3000A) The current is limited to the current value (1500A) that can be cut off by the circuit breaker CBSi as an individual overcurrent protection device below. Therefore, before the high-speed fuse UFA is cut off, the wiring breaker CBi Can be safely and reliably shut off. For this reason, even if a short circuit accident occurs at the end of the individual auxiliary power supply circuit, the power supply of the entire auxiliary power supply circuit will not be stopped by simply disconnecting only the individual auxiliary power supply circuit where the short circuit accident occurred. The remaining sound individual auxiliary power feeding circuit can continue to operate without stopping.

  FIG. 3 shows a power feeding circuit according to a second embodiment of the present invention.

  The power supply circuit of the second embodiment is obtained by replacing the high-speed fuse FE connected in parallel with the current limiting resistor RE in the current limiting circuit in the power supply circuit of the first embodiment with a semiconductor switch Q. Other configurations are the same as those in the first embodiment.

  FIG. 4 shows an equivalent circuit of one individual auxiliary machine power supply circuit ALSi of the second embodiment shown in FIG.

  The total circuit inductance LΣp2 up to the end Pi point of the individual auxiliary power feeding circuit shown in FIG. 3 is LΣp2 = LB + LA + LQi + LSi, and the total circuit resistance RΣp2 is RΣp2 = RBr + RA + RQi + RSi. Since the internal inductance LQi of the semiconductor switch Qi is much smaller than the internal inductance LFi of the high-speed fuse FEi in the first embodiment, the total circuit inductance LΣp2 is further smaller than the total circuit inductance LΣp1 of the first embodiment.

  Therefore, in the second embodiment, the total circuit time constant TΣp2 (TΣp2 = LΣp2 ÷ RΣp2) is reduced, the short-circuit current is increased, and the increase rate of the short-circuit current is as shown by the characteristic line C in FIG. It becomes larger than the characteristic line B of 1. As a result, when a short circuit accident occurs at the feed circuit terminal Pi point, the short circuit current rises at a fast speed according to the characteristic line C. The circuit breaker CBSi for wiring detects an overcurrent at the point C0 where the current reaches the breaking current set value Is, and starts the circuit breaking operation, but the actual circuit breaking operation (contact opening) of the circuit breaker CBi is delayed.

  On the other hand, the current limiting device CLi using the semiconductor switch Qi and the current limiting resistor FEi includes a switching control device SC as shown in FIG. 5 in order to control the semiconductor switch Qi according to the circuit current I.

  The switching control device SC of the semiconductor switch Qi includes a control unit CTR configured by an electronic circuit, a current detector IDi that detects a circuit current of the individual auxiliary power supply circuit ALSi, and a current setting that sets a cutoff current value of the semiconductor switch Qi. Has a device VRi. The control unit CTR compares the current I detected by the current detector IDi with the cutoff current set value ICs set in the current setter VRi, and turns on the semiconductor switch Qi in a normal current range where I <ICs. A signal is sent to turn on the semiconductor switch Qi. As a result, the current limiting resistor REi of the current limiting device CLi is short-circuited, and no load current flows through it.

  In an overcurrent state where I> ICs, the control unit CTR immediately sends an off signal to the semiconductor switch Qi, turns off the semiconductor switch Qi with almost no time delay, releases the short circuit of the current limiting resistor REi, and loads current I is commutated to the current limiting resistor REi to limit the load current.

  Next, the interruption | blocking operation | movement at the time of the short circuit accident in Example 2 comprised in this way is demonstrated with reference to FIG.

  In the second embodiment, the breaking current set value ICs of the semiconductor switch Qi is set to 600A.

  The current limiting device CLi uses a semiconductor switch Qi having a small internal inductance as a high-speed switching element that opens and closes both ends of the current limiting resistor REi. Therefore, a short circuit accident occurs at the Pi point of the terminal of the individual auxiliary power supply circuit ALSi of the power supply circuit. When this occurs, the short circuit current flowing through the individual auxiliary power supply circuit ALS1 rises at a larger current increase rate than the short circuit current in the first embodiment indicated by the characteristic line B as indicated by the characteristic line C in FIG. When this short-circuit current reaches the breaking current set value (300A) of the wiring breaker CBSi at the point C0 in FIG. 8, the breaking breaker CBS1 starts breaking operation. Further, when the short-circuit current rises and reaches a point C1 that reaches the breaking current set value ICs (= 600 A) of the switching control device SC (FIG. 5), the switching control device SC detects this, and C2 slightly delayed from this point. In this respect, an off signal is given to the semiconductor switch Qi of the current limiting device CLi. As a result, the semiconductor switch Qi starts an off operation at the point C2 and turns off at the point C3.

  When the semiconductor switch Qi is turned off, the short-circuit current is commutated to the current limiting resistor REi, and is limited to a current determined by the resistance value Rei of the current limiting resistor REi (here, about 1500 A). The circuit breaker CBSi for wiring starts breaking the current limited by opening the contact by the overcurrent breaking operation from the point C4 delayed for a predetermined time, and completes the breaking at the point C5.

  At this time, at the point C2 where the semiconductor switch Qi starts to turn off, the upstream protection device UFA does not operate because the short-circuit current has not reached the cutoff current set value CU (300A) of the upstream protection device UFA.

  That is, since the protection coordination between the upstream protection device UFA and the downstream protection device CBSi is taken, the short-circuit current is earlier than the upstream protection device UFA, and is shut off by the downstream protection device CBSi and not by the upstream protection device UFA. Therefore, the power supply stop of the entire auxiliary power supply circuit AL does not occur.

  Since the semiconductor switch Qi is capable of high-speed switching, the current-limiting operation can be performed in a short time even when the short-circuit current rises sharply, so that the current-limiting device CLi starts the current-limiting operation at high speed. Protection coordination between the upstream protection device UFA and the downstream protection device CBSi of the auxiliary power feeding circuit AL can be reliably achieved. As a result, it is possible to prevent the power supply stop of the entire auxiliary power supply circuit AL and to improve the safety and reliability of the electric propulsion device.

  FIG. 6 shows a third embodiment of the present invention.

  The power supply circuit of the third embodiment is a semiconductor switch Qi (Q1) of a current limiting device CLi (CL1 to CLn) provided in each individual auxiliary power supply circuit ALSi (ALS1 to ALSn) of the power supply circuit of the second embodiment. Since the internal inductance of .about.Qn) is small, reactors Li (L1 to Ln) are connected in series to the individual auxiliary machine power supply circuits ALSi (ALS1 to ALSn) to compensate for this.

  Accordingly, as shown in an equivalent circuit in FIG. 7, the total circuit inductance LΣp3 to the terminal Pi of each individual auxiliary power supply circuit ALSi becomes LΣp3 = LB + LA + Li + LSi, and the added reactor Li is added to the total circuit inductance LΣp2 of the second embodiment. The inductance Li is added and becomes larger than this. When the inductance Li of the reactor Li is set to a value corresponding to the internal inductance LFi of the high-speed fuse FEi of the current limiting device of the first embodiment, the total circuit inductance LΣp3 can be set to a value corresponding to the total circuit inductance LΣp1 in the first embodiment.

  In this way, when a short circuit accident occurs at the terminal Pi of the individual auxiliary power supply circuit ALSi, the increase rate of the short circuit current is suppressed to the same increase rate as the short circuit current of Example 1 shown by the characteristic line B in FIG. be able to.

  In the power supply circuit of the third embodiment, a short circuit accident occurs, and the circuit breaker CBSi for the wiring of the individual auxiliary power supply circuit ALSi at the point B0 on the short circuit current shown in the characteristic diagram 8 is the cut-off current set value Is (300A ) Is detected and the shutoff operation is started. At the point B1 ′ when the short-circuit current further rises and reaches the cutoff setting current ICs (600A) of the current limiting device CLi, the control unit CTR of the switching control device SC (FIG. 5) detects this and supplies it to the semiconductor switch Qi. Send off signal to turn it off. As a result, the short-circuit current is commutated to the current limiting resistor REi at approximately the point B1 ′, so that the short-circuit current rises more slowly as indicated by the characteristic line B ′ and is determined by the resistance value Rei of the current limiting resistor REi. The current value Ir rises to 1500 (A), and at the point B3 as in the first embodiment, the circuit breaker CBSi of the individual auxiliary power feeding circuit ALSi opens the switching contact and cuts off the short-circuit current.

  At this time, the short-circuit current is limited to a current equal to or lower than the operating current of the upstream protection device UFA determined by the current limiting resistance and is interrupted by the wiring breaker CBSi of the individual auxiliary power feeding circuit ALSi. The device UFA does not work. For this reason, when a short-circuit accident occurs, power supply of the entire auxiliary power supply circuit AF is not stopped, only the individual auxiliary power supply circuit ALSi in which the short-circuit accident has occurred is disconnected, and other healthy individual auxiliary power supply circuits Can continue to drive.

  FIG. 9 shows a fourth embodiment of the present invention.

  The power supply circuit according to the fourth embodiment is a reactor for each individual auxiliary power supply circuit ALSi (ALS1 to ALSn) provided in each individual auxiliary power supply circuit ALSi (ALS1 to ALSn) of the power supply circuit according to the first embodiment. Li (L1 to Ln) is connected in series to compensate for the shortage of the circuit inductance or the current limiting device.

  As a result, as shown in an equivalent circuit in FIG. 10, the total circuit inductance LΣp4 up to the terminal Pi of each individual auxiliary power supply circuit ALSi is LΣp4 = LBr + LAr + LFi + LSi, and the added reactor Li Li The inductance Li is added and becomes larger than this.

  Therefore, in the power supply circuit of the fourth embodiment, even when the internal inductance of the high-speed fuse FEi (FE1 to FEn) used in the current limiting device CLi (CL1 to CLn) is small or the circuit inductance LA is small, the reactor Li is used. By adding, the total circuit inductance LΣp4 can be made equal to or greater than the total circuit inductance LΣp1 in the first embodiment.

  In this way, when a short circuit accident occurs at the terminal Pi of the individual auxiliary power supply circuit ALSi, the short circuit current rise speed is at least the same as the short circuit current of the first embodiment shown by the characteristic line B in FIG. Can be suppressed.

  Therefore, in the power supply circuit according to the fourth embodiment, when a short circuit accident occurs, the individual auxiliary power supply circuit at the point B0 on the short circuit current line indicated by the characteristic line B in FIG. The ALSi wiring breaker CBSi detects the breaking current set value Is (300 A) and starts the breaking operation. The high-speed fuse FEi of the current limiting device CLi starts a cut-off operation (melting) at a point B1 where the short-circuit current further rises and exceeds the cut-off current set value (2000A), and cuts off while the short-circuit current is limited. When the cut-off operation (melting) is completely completed at the point B2 and the short-circuit current is commutated to the current-limiting resistor REi, the short-circuit current is limited to the current (1500 A) determined by the resistance value Rei of the current-limiting resistor REi. It is. When the time corresponding to the circuit breaker CBSi operation delay time (13 ms) elapses from point B0, the circuit breaker CBSi opens the switching contact at the point B3 and starts the interruption of the fault current, and the circuit breaks at the point B4. Complete.

  At this time, the short-circuit current is limited to a current equal to or lower than the operating current of the upstream protection device UFA determined by the current limiting resistance and is interrupted by the wiring breaker CBSi of the individual auxiliary power feeding circuit ALSi. The device UFA does not work. For this reason, when a short-circuit accident occurs, power supply of the entire auxiliary power supply circuit AF is not stopped, only the individual auxiliary power supply circuit ALSi in which the short-circuit accident has occurred is disconnected, and other healthy individual auxiliary power supply circuits Can continue to drive.

Br: Battery power supply using lithium ion battery ML: Main power supply circuit DSM: Main power supply circuit switch UMF: Main power supply circuit protection device (high-speed fuse)
CBM: Circuit breaker for main circuit wiring M: Propulsion motor (main circuit load)
AL: Auxiliary power supply circuit DSA: Auxiliary power supply circuit switch UFA: Auxiliary power supply circuit upstream protection device (high-speed fuse)
ALSi (ALS1-ALSn): Individual auxiliary machine power supply circuit CBSi (CBS1-CBSn): Circuit breaker for individual auxiliary machine power supply circuit wiring CLi (CL1-CLn): Current limiting device FEi (FE1-FEn): High-speed fuse REi (RE1 ~ REn): Current limiting resistance Si (S1 ~ Sn): Auxiliary equipment

Claims (4)

  A main power supply circuit that supplies power to the propulsion motor from a power source configured by a battery, such as a power source configured by a lithium ion battery, having a small internal resistance and circuit inductance, and for supplying power from the power source to a plurality of auxiliary devices A power supply circuit of an electric propulsion device having an auxiliary power supply circuit having an individual auxiliary power supply circuit branched for each auxiliary device, and a source flow path upstream of the individual auxiliary power supply circuit of the auxiliary power supply circuit. An upstream overcurrent protection device that protects the auxiliary machine power supply circuit from overcurrent, and a downstream overcurrent protection device that protects the individual auxiliary machine power supply circuit from overcurrent in each downstream individual auxiliary machine power supply circuit A high-speed current limiting device is connected in series to each of the downstream overcurrent protection devices of the individual auxiliary power supply circuit, and when a short-circuit fault occurs in the individual auxiliary power supply circuit, the short-circuit current is Previous by equipment The current is limited to a current equal to or lower than the cut-off current set value of the upstream overcurrent protection device and cut off by the downstream overcurrent protection device of the individual auxiliary power supply circuit in which the short circuit accident has occurred earlier than the upstream overcurrent protection device. The protection method for the power supply circuit of the electric propulsion device, characterized by disconnecting the accident circuit.   2. The electric propulsion device feeding circuit according to claim 1, wherein the high-speed current limiting device is configured by connecting in parallel a current-limiting resistor and high-speed switch means that closes at a normal current and opens at a high speed when an overcurrent occurs. Protection method.   3. The electric propulsion device power supply circuit protection system according to claim 2, wherein the high-speed switch means is a high-speed fuse or a semiconductor switch device.   The protection system for the power supply circuit of the electric propulsion device according to any one of claims 1 to 3, wherein a current limiting reactor is inserted in series in each of the auxiliary power supply circuit or the individual auxiliary power supply circuit.

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