JP6449598B2 - Electric vehicle - Google Patents

Description

  The present invention relates to an electric vehicle using a motor generator as a power source.

  As this type of electric vehicle, there is a vehicle described in Patent Document 1, for example. The electric vehicle described in Patent Literature 1 includes a motor generator as a driving power source that is driven based on electric power from a battery. The motor generator generates power for running the vehicle, and performs regenerative power generation that converts kinetic energy of the vehicle into electric energy during deceleration such as braking. In such an electric vehicle, the energy efficiency is improved by charging and collecting the regenerative electric power generated by the motor generator in the battery.

JP 2010-36594 A

  When the electric vehicle as described above is applied to a large vehicle such as a bus, for example, two sets of drive mechanisms (banks) composed of a battery and a motor generator are mounted because the power required for vehicle travel increases. Can be considered. More specifically, two sets of drive mechanisms are directly connected via gears, and the drive wheels are driven by transmitting power from the two sets of drive mechanisms to the drive wheels of the vehicle via the gears. According to such a configuration, since the power transmitted to the drive wheels is increased, it is possible to travel a large vehicle.

  On the other hand, in such an electric vehicle, when an abnormality occurs in one of the drive mechanisms, it is conceivable that the motor generator of the drive mechanism is stopped and the vehicle travels with only one normal drive mechanism. By the way, even when only one drive mechanism is driven, the power of the normal drive mechanism is transmitted to the motor generator of the abnormal drive mechanism via the gear, so the motor generator of the abnormal drive mechanism is rotated. . If the occurrence of an abnormality in the abnormal drive mechanism is a failure of the inverter or the motor generator, the field weakening control to weaken the counter electromotive force due to this rotation becomes impossible, so the counter electromotive force generated in the motor generator is transferred to the battery. It will be charged continuously. In order to prevent this continuous charging from overcharging the battery, it is necessary to cut off the main relay interposed between the battery and the motor generator. From the standpoint of preventing relay burnout, the main relay may be interrupted in some cases, and the battery may be damaged by overcharging.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to ensure that even if an abnormality occurs in any one drive mechanism in an electric vehicle equipped with two or more sets of drive mechanisms. An object of the present invention is to provide an electric vehicle capable of avoiding battery damage due to charging.

  An electric vehicle that solves the above problems includes a rechargeable battery (121, 221) and a motor generator (150) that generates power necessary for vehicle travel based on the electric power from the battery and charges the battery with regenerative power. , 250), a charging state detection unit (130, 230) for detecting the charging state of the battery, and a control unit (160, 260) for controlling driving of the motor generator (100, 260). 200) and a power transmission mechanism (300) for transmitting the power generated by the motor generators of each of the plurality of drive mechanisms to the drive wheels of the vehicle, and the control unit has an abnormality in its drive mechanism. When it occurs, when the charge state of the battery is monitored by the charge state detection unit and it is determined that the battery is overcharged , Notifies the stop command to the other drive mechanism, when it receives a stop command transmitted from the other drive mechanism stops its drive mechanism.

  According to this configuration, after an abnormality has occurred in any of the plurality of drive mechanisms, the motor generator of the normal drive mechanism stops when an overcharge occurs in the battery of the drive mechanism in which the abnormality has occurred. . As a result, the motor generator of the abnormal drive mechanism is not rotated in conjunction with the operation of the motor generator of the normal drive mechanism, so that regenerative power is not charged to the battery from the motor generator of the abnormal drive mechanism. Therefore, damage to the battery due to overcharging can be avoided.

  According to the present invention, in an electric vehicle equipped with two or more sets of drive mechanisms, even if any one of the drive mechanisms is abnormal, it is possible to avoid damage to the battery due to overcharge. .

The block diagram which shows the schematic structure about one Embodiment of an electric vehicle. The circuit diagram which shows the electric constitution of the electrical storage apparatus about the electric vehicle of embodiment. The flowchart which shows the procedure of the abnormality monitoring process performed by ECU about the electric vehicle of embodiment. The flowchart which shows the procedure of the drive mechanism stop process performed by ECU about the electric vehicle of embodiment. The sequence chart which shows the operation example about the electric vehicle of embodiment.

  Hereinafter, an embodiment of an electric vehicle will be described. First, the outline | summary of the electric vehicle of this embodiment is demonstrated.

  As illustrated in FIG. 1, the electric vehicle 10 according to the present embodiment includes, for example, a large bus, and includes a first drive mechanism 100, a second drive mechanism 200, and a power transmission mechanism 300. The power transmission mechanism 300 transmits the power generated by the first drive mechanism 100 and the second drive mechanism 200 to the left and right drive wheels 11 and 12 of the vehicle. That is, the electric vehicle 10 travels using the first drive mechanism 100 and the second drive mechanism 200 as power sources.

  The first drive mechanism 100 includes a fuel cell device 110, a power storage device 120, a charge state detection unit 130, an inverter 140, a motor generator 150, and an ECU (electronic control unit) 160 as a control unit.

  The fuel cell device 110 includes a fuel tank 111, a fuel cell stack 112, and a converter 113. The fuel tank 111 stores gas fuel such as hydrogen in a high pressure state. The fuel tank 111 depressurizes the stored gas fuel and supplies it to the fuel cell stack 112. The fuel cell stack 112 generates power by a chemical reaction between gas fuel supplied from the fuel tank 111 and air supplied from a blower (not shown). The converter 113 boosts the DC power generated by the fuel cell stack 112 to a voltage suitable for the supply of the inverter 140 and applies it to the inverter 140.

  Power storage device 120 includes a battery 121, an intermittent circuit 122, and a converter 123.

  As shown in FIG. 2, the high potential side wiring 126 and the low potential side wiring 127 are connected to the high potential side terminal and the low potential side terminal of the battery 121, respectively. The high potential side wiring 126 and the low potential side wiring 127 are connected to the converter 123 through the intermittent circuit 122. A precharge resistor R is connected in parallel to the low potential side wiring 127. Further, a smoothing capacitor C1 is connected between the high potential side wiring 126 and the low potential side wiring 127.

  The interrupting circuit 122 includes a first relay 122a for intermittently connecting the high potential side wiring 126, a second relay 122b for intermittently connecting the low potential side wiring 127, and a precharge relay 122c connected in series to the precharge resistor R. The In the intermittent circuit 122, the power supply path between the battery 121 and the converter 123 can be intermittently switched by switching on / off states of the relays 122a to 122c.

  Converter 123 includes a reactor L, switching elements SW1 and SW2, and a smoothing capacitor C2. The switching elements SW <b> 1 and SW <b> 2 are connected in series between the high potential side wiring 141 and the low potential side wiring 142 of the inverter 140. Note that when at least one of the second relay 122b and the precharge relay 122c of the intermittent circuit 122 is in an ON state, the potential of the low potential side wiring 142 of the inverter 140 is the same as that of the low potential side wiring 127 of the battery 121. Become. The switching elements SW1 and SW2 are made of, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOS (Metal Oxide Semiconductor) transistor. Free-wheeling diodes D1 and D2 are connected in parallel to the switching elements SW1 and SW2, respectively. Reactor L is arranged between high potential side wiring 126 of battery 121 and connection point P of switching elements SW1 and SW2. The smoothing capacitor C <b> 2 is disposed between the high potential side wiring 141 and the low potential side wiring 142 of the inverter 140. Converter 123 boosts the voltage of battery 121 and supplies it to inverter 140 by ON / OFF control of switching elements SW1 and SW2.

  The power storage device 120 includes a first voltage sensor 124 and a second voltage sensor 125. The first voltage sensor 124 detects a potential difference (battery voltage) VL between the high potential side wiring 126 and the low potential side wiring 127 of the battery 121. The second voltage sensor 125 detects a potential difference (inverter voltage) VH between the high potential side wiring 141 and the low potential side wiring 142 of the inverter 140. Each voltage sensor 124, 125 outputs the detected voltage value to ECU 160.

  The charge state detection unit 130 detects a state quantity of the battery 121, for example, an output voltage, an output current, and a temperature of the battery 121, and outputs the detected state quantity of the battery 121 to the ECU 160.

  As shown in FIG. 1, inverter 140 drives motor generator 150 by converting DC power supplied from fuel cell device 110 or power storage device 120 into three-phase AC power and supplying it to motor generator 150. Inverter 140 also converts regenerative power (three-phase AC power) from motor generator 150 into DC power and supplies it to converter 123. At this time, converter 123 steps down the DC power supplied from inverter 140 to a voltage suitable for supply to battery 121 and supplies the voltage to battery 121. Thereby, the battery 121 is charged.

  ECU 160 controls direct current power supplied from fuel cell device 110 to inverter 140 by controlling driving of fuel cell stack 112 and converter 113. In addition, ECU 160 controls DC power supplied from power storage device 120 to inverter 140 by controlling driving of intermittent circuit 122 and converter 123.

  For example, ECU 160 sets charge power limit value Win based on the state quantity of battery 121 detected by charge state detection unit 130 when motor generator 150 is performing regeneration. The charge power limit value Win indicates a limit value of the charge power of the battery 121. When the battery 121 is in a fully charged state, the value is set to “0”. The charging power limit value Win is set so as to gradually decrease to a predetermined value (<0) as the charging power of the battery 121 decreases. ECU 160 controls driving of motor generator 150 so that the electric power charged in battery 121 falls within the range of charge power limit value Win when regenerative electric power is generated by motor generator 150. This prevents the regenerative power supplied to the battery 121 from becoming excessive.

  In addition, when charging power limit value Win shows a positive value while motor generator 150 is performing regeneration, it indicates that battery 121 may be overcharged. Therefore, ECU 160 can determine that battery 121 is overcharged when charging power limit value Win is a positive value while motor generator 150 is performing regeneration.

  ECU 160 controls inverter voltage VH to a target voltage based on battery voltage VL detected by first voltage sensor 124 and inverter voltage VH detected by second voltage sensor 125. The target voltage is set to a value suitable for the supply of the inverter 140.

  Further, ECU 160 controls the drive of inverter 140 to control the voltage supplied to motor generator 150 by PWM (pulse width modulation). ECU 160 controls driving of motor generator 150 through this PWM control.

  The second drive mechanism 200 has the same configuration as the first drive mechanism 100. That is, the second drive mechanism 200 includes the fuel cell device 210, the power storage device 220, the charge state detection unit 230, the inverter 240, the motor generator 250, and the ECU 260, similarly to the first drive mechanism 100. The fuel cell device 210 includes a fuel tank 211, a fuel cell stack 212, and a converter 213. In addition, the power storage device 220 includes a battery 221, an intermittent circuit 222, and a converter 223. Since the structure and operation of these elements of the second drive mechanism 200 are the same as the structure and operation of each element of the first drive mechanism 100, their description is omitted.

  The power transmission mechanism 300 includes a gear 301, a propeller shaft 302, and a differential gear 303. The gear 301 is connected to the output shaft 151 of the motor generator 150 of the first drive mechanism 100 and the output shaft 251 of the motor generator 250 of the second drive mechanism 200. The gear 301 rotates the propeller shaft 302 by transmitting the rotation of the output shafts 151 and 251 of the motor generators 150 and 250 to the propeller shaft 302. Since the output shafts 151 and 251 of the motor generators 150 and 250 are mechanically connected via the gear 301, when one of the output shafts is rotated, the other is interlocked with the other output shaft. The output shaft also rotates, so-called accompanying rotation occurs.

  The differential gear 303 rotates the drive shafts 13 and 14 by transmitting the rotation of the propeller shaft 302 to the left and right drive shafts 13 and 14 of the vehicle. Due to the rotation of the drive shafts 13 and 14, the drive wheels 11 and 12 respectively connected to the tips of the drive shafts 13 and 14 rotate and the vehicle travels.

  Next, an operation when abnormality occurs in the first drive mechanism 100 and the second drive mechanism 200 will be described.

  For example, when an abnormality occurs only in the first drive mechanism 100, the ECU 160 of the first drive mechanism 100 stops the first drive mechanism 100 when detecting the abnormality. Specifically, ECU 160 performs processing such as stopping driving motor generator 150. Therefore, in this situation, the vehicle travels only by driving the second drive mechanism 200. ECU 160 also performs field weakening control on motor generator 150 to suppress back electromotive force generated in motor generator 150 due to the accompanying rotation. As a result, it is possible to suppress the motor generator 150 from becoming a traveling load.

  On the other hand, when an abnormality occurs only in the second drive mechanism 200, the ECU 260 of the second drive mechanism 200 detects the abnormality and similarly stops the second drive mechanism 200, and the second motor generator 250 Perform field-weakening control.

  By the way, for example, when an abnormality occurs only in the first drive mechanism 100 and the vehicle travels only with the second drive mechanism 200, if an abnormality occurs in the motor generator 150 or the inverter 140 of the first drive mechanism 100, the ECU 160. Cannot perform field-weakening control properly. In such a situation, the counter electromotive force generated in the motor generator 150 due to the accompanying rotation cannot be suppressed. At this time, ECU 160 controls inverter voltage VH to a target voltage, so that back electromotive force generated in motor generator 150 is charged in battery 121. If such charging continues, the battery 121 may be abnormal due to overcharging. A similar problem may occur when the vehicle travels only with the first drive mechanism 100.

  Therefore, in the electric vehicle 10 according to the present embodiment, when an abnormality occurs in one of the first drive mechanism 100 and the second drive mechanism 200, the ECU of the drive mechanism in which the abnormality has occurred monitors the state of charge of the battery. To do. When the ECU of the drive mechanism in which the abnormality has occurred detects that the battery is overcharged, the overdrive state is not continued in the battery of the abnormal drive mechanism by stopping the normal drive mechanism of the other party. Like that. Details will be described below.

  Each ECU 160, 260 repeatedly executes the process shown in FIG. 3 at a predetermined cycle. Below, only the process which ECU160 of the 1st drive mechanism 100 performs is demonstrated for convenience.

  As shown in FIG. 3, the ECU 160 first determines whether or not an abnormality has occurred in the first drive mechanism 100 (S10). When the abnormality of the first drive mechanism 100 is detected (S10: YES), the ECU 160 stops driving the first drive mechanism 100 (S11), and notifies the second drive mechanism 200 to that effect (S12). Subsequently, ECU 160 determines whether or not charging power limit value Win is equal to or greater than zero (S13). When charging power limit value Win is equal to or greater than zero (S13: NO), ECU 160 determines that overcharge occurs in battery 121 of first drive mechanism 100, and notifies ECU 260 of second drive mechanism 200 of a stop command. (S14), a series of processing ends.

  Further, ECU 160 cannot detect abnormality of first drive mechanism 100 (S10: NO), or when charge power limit value Win is a negative value smaller than zero (S13: YES), a series of steps. Terminate the process.

  Each ECU 160, 260 also repeatedly executes the process shown in FIG. 4 at a predetermined cycle. Below, only the process which ECU160 of the 1st drive mechanism 100 performs is demonstrated for convenience.

  As shown in FIG. 4, the ECU 160 first determines whether or not an abnormality has occurred in the second drive mechanism 200 (S20). The ECU 160 determines that an abnormality has occurred in the second drive mechanism 200 when the second drive mechanism 200 notifies the stop (S20: YES), and then issues a stop command from the second drive mechanism 200. It is determined whether the notification has been received (S21). Then, when a stop command is notified from the second drive mechanism 200 (S21: YES), the ECU 160 stops the first drive mechanism 100 (S22).

  Further, when there is no abnormality in the second drive mechanism 200 (S20: NO), or when there is no stop command from the second drive mechanism 200 (S21: NO), the ECU 160 ends the series of processes.

  Next, with reference to FIG. 5, the operation example of the electric vehicle 10 of this embodiment is demonstrated.

  As shown in FIG. 5, for example, when an abnormality occurs in the first drive mechanism 100, when the ECU 160 of the first drive mechanism 100 detects an abnormality (S30), the ECU 160 stops the first drive mechanism 100 (S31). This is notified to the second drive mechanism 200 (S32). At this time, when the ECU 260 of the second drive mechanism 200 receives a notification that the first drive mechanism 100 is stopped (S40), it determines that an abnormality has occurred in the first drive mechanism 100 (S41).

  On the other hand, after notifying that the first drive mechanism 100 is stopped (S32), the ECU 160 stops the charge command when the charge power limit value Win becomes zero or more (S33), that is, when the battery 121 is overcharged. Is notified to the second drive mechanism 200 (S34). At this time, when the ECU 260 of the second drive mechanism 200 receives a stop command (S42), the ECU 260 stops the second drive mechanism 200 (S43). As a result, the motor generator 150 of the first drive mechanism 100 does not rotate, so that regenerative power is not charged from the motor generator 150 to the battery 121. Therefore, damage of the battery 121 due to overcharging can be avoided in advance.

  In addition, the said embodiment can also be implemented with the following forms which changed this suitably.

  ECU 160 may determine whether or not overcharge occurs in battery 121 based on a value different from charging power limit value Win. For example, the ECU 160 estimates the charge amount of the battery 121 based on the state amount of the battery 121 detected by the charge state detection unit 130, and determines that the battery 121 is overcharged when the charge amount exceeds a predetermined value. May be. The same applies to the ECU 260.

  The structure of the intermittent circuit 122 can be changed as appropriate. For example, when the precharge resistor R is not provided in the low potential side wiring 127, the precharge relay 122 c may be excluded from the intermittent circuit 122. Further, the interrupting circuit 122 is not limited to the one that interrupts the power feeding path between the battery 121 and the converter 123. For example, the intermittent circuit 122 may be configured to intermittently connect a power supply path between the converter 123 and the inverter 140 or may be configured to intermittently connect a power supply path between the inverter 140 and the motor generator 150. In short, the intermittent circuit 122 may be any circuit that intermittently connects the power feeding path between the battery 121 and the motor generator 150.

  The structure of the power transmission mechanism 300 can be appropriately changed as long as the power generated by the motor generators 150 and 250 can be transmitted to the drive wheels 11 and 12 of the vehicle.

  The structures of the fuel cell devices 110 and 210 and the power storage devices 120 and 220 can be changed as appropriate. For example, the fuel cell devices 110 and 210 and the power storage devices 120 and 220 may have a structure without a converter.

  -The 1st drive mechanism 100 is not restricted to the structure which has the fuel cell apparatus 110 and the electrical storage apparatus 120, For example, the structure which has an engine and an electrical storage apparatus may be sufficient. Further, the first drive mechanism 100 may include only the power storage device 120. The same applies to the second drive mechanism 200.

  The electric vehicle 10 is not limited to a structure including the two drive mechanisms 100 and 200, and may have a structure including three or more drive mechanisms.

  -This invention is not limited to said specific example. That is, the above-described specific examples that are appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which embodiment mentioned above is provided can be combined as long as it is technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Electric vehicle 11, 12: Drive wheel 100: First drive mechanism 200: Second drive mechanism 121, 221: Battery 130, 230: Charging state detector 150, 250: Motor generator 300: Power transmission mechanism 160, 260: ECU 160 (control unit)

Claims (4)

Rechargeable batteries (121, 221), motor generators (150, 250) for generating power necessary for vehicle travel based on electric power from the batteries and charging the battery with regenerative power, and charging of the batteries A plurality of drive mechanisms (100, 200) having a charge state detection unit (130, 230) for detecting a state and a control unit (160, 260) for controlling the drive of the motor generator;
A power transmission mechanism (300) for transmitting the power generated by the motor generator of each of the plurality of drive mechanisms to the drive wheels of the vehicle,
The controller is
When an abnormality occurs in its own drive mechanism, the charge state detection unit monitors the charge state of the battery, and when it is determined that overcharge occurs in the battery, a stop command is notified to another drive mechanism And
An electric vehicle characterized by stopping its own drive mechanism when it receives a stop command transmitted from the other drive mechanism.   The controller is
  When an abnormality occurs in its own drive mechanism, the charge state detection unit monitors the charge state of its own battery, and when it is determined that overcharge occurs in its own battery, another drive mechanism The electric vehicle according to claim 1, wherein a stop command is notified to the vehicle. An intermittent circuit (122, 222) for intermittently connecting a power feeding path between the battery and the motor generator;
The controller is
3. The electric vehicle according to claim 1, wherein when it is determined that overcharge occurs in the battery, the drive mechanism is stopped by interrupting the power supply path by the intermittent circuit. 4. The controller is
Calculating a charge power limit value indicating a limit value of charge power to the battery based on a charge state of the battery detected through the charge state detection unit;
The electric vehicle according to any one of claims 1 to 3, wherein it is determined whether or not an overcharge has occurred in the battery based on the charge power limit value.

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