JP5808707B2 - Electric car - Google Patents

Description

  The present invention relates to an electric vehicle that converts electric power supplied from an in-vehicle power storage device and / or electric power supplied from an overhead line through an in-vehicle overhead line contact terminal to an in-vehicle inverter and supplies the converted electric power to a motor for driving the vehicle.

  2. Description of the Related Art Conventionally, an electric vehicle that travels by electric power from an overhead wire or by a motor driven by electric power of a vehicle-mounted battery has been proposed (Patent Document 1).

  In such an electric vehicle, in the contact state between the overhead wire and the on-vehicle current collector, the on-vehicle battery is charged by the power supplied from the overhead wire, and the power is converted and supplied to the motor through the on-vehicle inverter. To be run. In this electric vehicle, when traveling on a road without the overhead line, electric power is supplied from the battery to the motor via the inverter (summary of Patent Document 1).

  Patent Document 2 discloses a control device for an electric vehicle in the electric railway field.

Republished WO2009 / 001788 Republished WO 2008/018131

  In the electric vehicle disclosed in Patent Document 2, a DC / DC converter using a power storage device as an input power source is connected in parallel with an inverter that supplies electric power to a driving motor. In this DC / DC converter, the voltage of the power storage device is boosted to the input voltage of the inverter by a reactor and upper and lower arm switching elements.

  A current collector is provided between the input terminals of the inverter via a switch. The current collector is in sliding contact with the overhead wire and receives power from the overhead wire.

  In the electric vehicle configured as described above, the motor is basically driven through the inverter by the electric power of the voltage obtained by boosting the voltage of the power storage device by the DC / DC converter or the electric power from the overhead line. The

  In the electric vehicle according to Patent Document 2, in order to prevent an inrush current from the overhead line at the time of contact between the overhead line and the on-vehicle current collector, the current collector is at a position separated from the overhead line, When the vehicle-mounted current collector is brought into contact with the overhead wire and transits to the running mode by the power of the overhead line from the traveling mode in which the power of the power storage device only travels, first, in the open state of the switch, In this contact state, the input voltage of the inverter is gradually increased to the voltage of the overhead line by the DC / DC converter using the electric power of the power storage device, and the input voltage of the inverter and the When the voltage difference with the voltage of the overhead wire becomes a sufficiently small value, an inrush current is generated by the voltage difference or the switch is changed from the open state to the closed state. Are disclosed as possible to avoid the contact becomes rough (Patent Document 2 [0025], [0026]).

  However, the electric vehicle control device in the electric railway field according to the above-described prior art is for high withstand voltage applicable to an infrastructure having an overhead wire voltage of 600 [V] to 1500 [V] ([0022] of Patent Document 2). Therefore, it is extremely difficult in terms of cost and size to apply such a technique as it is to a general-purpose electric vehicle capable of operating with a power supply of about 100 [V] to 200 [V].

  If it is applied, the high voltage of the overhead wire is directly applied to the inverter and the motor via the inverter, so that the power consumption of the inverter increases and the heat generation countermeasure for preventing heat generation also increases the cost. In addition, a high withstand voltage motor is required as the motor, which increases the cost and enlarges the motor itself.

  The present invention has been made in consideration of such problems, and even if a high voltage is applied from the overhead line to the electric railway field, the motor and the inverter that supplies power to the motor are lower than the high voltage. An object of the present invention is to provide an electric vehicle that can apply an appropriate voltage and can prevent heat generation of the inverter and reduce the size of the inverter and the motor.

  The electric vehicle according to the present invention is an electric vehicle in which electric power supplied from an on-vehicle power storage device and / or electric power supplied from an overhead wire through an on-vehicle overhead wire contact terminal is converted by an inverter and supplied to a motor for driving the vehicle. A first DC / DC converter provided between a power storage device terminal and the overhead wire contact terminal; a second DC / DC converter provided between the overhead wire contact terminal and the inverter terminal; and the first and second DCs. A control device for controlling the DC / DC converter, wherein the control device is configured such that, when power is supplied from the overhead wire through the overhead wire contact terminal, the voltage applied to the inverter corresponds to the required power of the motor. 2 When the DC / DC converter is controlled and the overhead contact terminal is separated from the overhead line, the voltage of the power storage device is When the voltage is equal to or higher than the voltage, the first DC / DC converter is controlled to be in a directly connected state, and the second DC / DC converter is controlled so that the voltage applied to the inverter corresponds to the required power of the motor. When the voltage of the power storage device is less than the predetermined voltage, the first DC / DC converter is controlled so that the voltage applied to the inverter corresponds to the required power of the motor, and the second DC / DC The DC converter is controlled to be in a directly connected state.

  According to the present invention, since the second DC / DC converter is provided between the overhead wire contact terminal and the terminal of the inverter, even if a high voltage is applied from the overhead line, the second DC / DC converter is an electrical shock absorber. Thus, the application of a high voltage to the inverter is avoided, and as a result, the heat generation of the inverter can be suppressed, and the inverter and the motor can be appropriately connected with the lower voltage than the high voltage of the overhead line via the second DC / DC converter. A voltage can be applied.

  In this case, the control device is configured to change the voltage between the overhead wire contact terminals to a voltage corresponding to the overhead wire feeding voltage when the overhead wire contact terminal is shifted from the state of being separated from the overhead wire to the contact state. The second DC / DC converter controls the first DC / DC converter, and the second DC / DC converter controls the voltage applied to the inverter to correspond to the required power of the motor. Generation of a large inrush current from the overhead line to the electric vehicle can be prevented when the overhead line contact terminal contacts the overhead line while traveling correspondingly. That is, when the overhead wire contact terminal of the electric vehicle comes into contact with the overhead wire, it is not necessary to limit the required power of the motor, and the occurrence of inrush current can be prevented.

  In addition, when the control device shifts from the state where the overhead wire contact terminal is separated from the overhead wire to the contact state, the control device supplies the storage device supplied via the first DC / DC converter via the overhead wire. After controlling the first DC / DC converter so that the charging current gradually increases, when the potential difference between the input and output of the first DC / DC converter falls within a predetermined value, the first DC / DC converter is brought into a direct connection state. By controlling the switching loss of the first DC / DC converter, the efficiency of charging the power storage device can be increased.

  Further, the control device can reduce power loss of the first and second DC / DC converters during the regeneration by controlling the first and second DC / DC converters to be in a directly connected state during the regeneration of the motor. Thus, the regenerative power can be recovered more efficiently.

  According to the present invention, since the second DC / DC converter is provided between the overhead wire contact terminal and the inverter terminal, even if a high voltage in the electric railway field is applied from the overhead wire, the motor and the motor An appropriate voltage lower than the high voltage can be applied to the inverter that supplies electric power to the inverter, thereby preventing the inverter from generating heat and reducing the size of the inverter and the motor.

It is a circuit block diagram which shows the structure of a vehicle electric power feeding traffic system provided with the electric vehicle which concerns on this embodiment. It is a circuit diagram of an inverter in an electric vehicle. It is a main flowchart of a vehicle electric power feeding traffic system provided with the electric vehicle which concerns on this embodiment. It is an electric power feeding control flowchart of a vehicle electric power feeding traffic system provided with the electric vehicle which concerns on this embodiment. It is a chart explaining the driving mode of an electric vehicle. It is a time chart explaining an example of the relationship between the transition of the driving mode of an electric vehicle, and each physical quantity.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an electric vehicle 10 according to this embodiment, and an electric wire feeding voltage (simply a DC high voltage) via an overhead wire L (a positive-side overhead wire L1 and a negative-side overhead wire L2). This is also referred to as a power supply voltage.) A configuration of a vehicle power supply traffic system 14 including an external power supply device 12 that supplies power of Vh is shown.

  The external power supply device 12 can be configured by a power supply device for power transmission only or a power supply device that can be charged and discharged including a power storage device. In this embodiment, a chargeable / dischargeable power supply device is employed.

  In the electric vehicle 10, an overhead wire contact terminal CT (a positive side overhead wire contact terminal CT 1 and a negative side overhead wire contact terminal CT 2) capable of contact power supply or contact charging with respect to the overhead line L is engaged with one end (end on the overhead line L side). Power receiving arm AM (positive power receiving arm AM1 and negative power receiving arm AM2).

  The power receiving arm AM is an arm telescopic type, an arm tilting type (the other end of the arm is attached to the vehicle body as a fulcrum, and the one end engaged with the overhead wire contact terminal CT is separated from the vehicle body), or an arm telescopic type and an arm tilting type. Can be used.

  The other end (the main body side of the electric vehicle 10) of the power receiving arm AM is electrically connected to one end side of the contactor S (the positive side contactor S1 and the negative side contactor S2).

  The other end side of the contactor S is connected to a wiring 28 including a positive-side wiring 28p and a negative-side wiring 28n.

  The electric vehicle 10 includes a power receiving arm AM having the overhead wire contact terminal CT engaged at one end, a contactor S, a motor 20 for driving the vehicle, and power conversion for supplying three-phase AC power to the motor 20. An inverter 22 as a device, a high-voltage battery 24 as a power storage device, a high-voltage battery 24 connected to a low-voltage side, and a high-voltage side connected to a wiring 28 that is the other end side of the contactor S and a DC input side of the inverter 22 A first DC / DC converter (hereinafter also referred to as a first converter) that supplies electric power obtained by boosting the voltage of the high-voltage battery 24 to the inverter 22 through a DC terminal 26 (positive DC terminal 26a and negative DC terminal 26b). ) 31 and the DC terminal 26 of the inverter 22 are connected to the low voltage side, and the high voltage side is connected to the wiring 28 which is the other end side of the contactor S. The 2DC / DC converters (hereinafter, also referred to as a second converter.) Comprising 32, and ECU (Electronic Control Unit) 40 as a control device. The ECU 40 controls the inverter 22, the first and second converters 31 and 32, the contactor S, the power receiving arm AM, and the motor 20.

  Although not shown, the rotating shaft of the motor 20 is engaged with the driving wheel through the transmission or as an in-wheel motor.

  The high voltage battery 24 is a secondary battery such as a lithium ion secondary battery or a capacitor. In this embodiment, a secondary battery is used.

  FIG. 2 shows a known circuit diagram of the inverter 22. The inverter 22 has a three-phase full-bridge configuration. When the motor 20 is powered, it performs DC / AC conversion, converts DC to three-phase AC power, and converts the U-phase coil, V-phase coil, and W of the motor 20. On the other hand, when the motor 20 is regenerated, DC power after AC / DC conversion is supplied between the DC terminals 26 through the second converter 32 and between the positive electrode side wiring 28p and the negative electrode side wiring 28n. The high voltage battery 24 is charged through the converter 31.

  The inverter 22 includes transistors 51u, 51v, 51w, 52u, 52v, 52w which are switching elements such as MOSFETs or IGBTs driven by the ECU 40, and diodes 53u, 53v, 53w, 54u, 54v, 54w connected in the reverse direction. Consists of

  The transistor 51u and the diode 53u constitute a U-phase upper arm element UMu, and the transistor 52u and the diode 54u constitute a U-phase lower arm element LMu. The transistor 51v and the diode 53v constitute a V-phase upper arm element UMv, and the transistor 52v and the diode 54v constitute a V-phase lower arm element LMv. The transistor 51w and the diode 53w constitute a W-phase upper arm element UMw, and the transistor 52w and the diode 54w constitute a W-phase lower arm element LMw.

  The upper arm side transistors 51u, 51v, 51w are switched by PWM (Pulse Width Modulation) signals Puu, Puv, Puw supplied from the ECU 40, and the lower arm side transistors 52u, 52v, 52w are supplied from the ECU 40. Switching is performed by PWM signals Pl, Plv, and Plw.

  In FIG. 1 again, as a voltage sensor, a voltage sensor 34 that detects a voltage (also referred to as a motor voltage) Vm between the DC terminals 26 of the inverter 22 and a terminal voltage (referred to as a battery voltage) Vb of the high-voltage battery 24 are used. A voltage sensor 36 for detecting and a voltage sensor 38 for detecting a DC voltage (referred to as a line voltage) V0 between the switches S are provided, and each detected voltage is read by the ECU 40.

  As current sensors, a current sensor 44 that detects a current (referred to as a motor current) Im that flows through the DC terminal 26a of the inverter 22, a current sensor 46 that detects a current (referred to as a battery current) Ib that flows through the high-voltage battery 24, and And a current sensor 48 that detects a current (referred to as an input current) I0 flowing through the converter 32, and each detected current is read by the ECU 40.

  The voltage sensor 36, the current sensor 46, and a temperature sensor (not shown) constitute an SOC sensor 56 that detects the SOC of the high-voltage battery 24 (a charge state or charge amount of 0 [%] to 100 [%]). The charge amount SOC is calculated by the ECU 40 based on the output.

  The motor voltage Vm is stepped down by a step-down converter (SDC) 52 and charges a low voltage battery 54 having a nominal value +12 [V].

  The low voltage battery 54 supplies electric power to an auxiliary machine such as a light (not shown) and also supplies electric power to the ECU 40.

  The first converter 31 has a known configuration, and includes transistors Q1 and Q2, which are switching elements to which diodes D1 and D2 are connected in opposite directions, a reactor Ra, and capacitors C1 and C2. As the transistors Q1 and Q2, power switching elements such as MOSFETs or IGBTs are employed.

  The transistor Q1 is switched by a PWM (Pulse Width Modulation) signal P1 supplied from the ECU 40, and the transistor Q2 is switched by a PWM signal P2 supplied from the ECU 40.

  The transistor Q1 and the diode D1 are the upper arm element UM1, and the transistor Q2 and the diode D2 are the lower arm element LM1.

  The second converter 32 is also a known configuration, and includes transistors Q3 and Q4, which are switching elements to which diodes D3 and D4 are connected in the opposite direction, a reactor Rb, and a capacitor C3. As the transistors Q3 and Q4, power switching elements such as MOSFETs or IGBTs are employed.

  The transistor Q3 is switched by a PWM signal P3 supplied from the ECU 40, and the transistor Q4 is switched by a PWM signal P4 supplied from the ECU 40.

  The transistor Q3 and the diode D3 are the upper arm element UM2, and the transistor Q4 and the diode D4 are the lower arm element LM2.

  Basically configured as described above, the electric vehicle 10 according to this embodiment, and the electric vehicle 10 is connected to the electric vehicle 10 via the overhead line L (the positive side overhead line L1 and the negative side overhead line L2). FIG. 3 is a main flowchart of the operation of the vehicle-powered transportation system 14, and FIG. 4 is a feed control flowchart. This will be described with reference to the travel mode explanatory chart 60 of FIG. The execution subject of the program according to the flowchart is the ECU 40 of the electric vehicle 10.

  In step S1, the ECU 40 determines whether or not an ignition switch (power switch) (not shown) is in an on state. If it is in an on state (step S1: YES), the electric vehicle 10 is regenerated in step S2. Whether it is in the state is determined by the direction of the motor current Im or the like.

  If it is not in the regenerative state (step S2: NO), it is determined that it is in a power running state, and in step S3, it is determined whether or not the charge amount SOC has dropped below the threshold value SOCth. If it exceeds SOCth (step S3: NO), in steps S4 and S5, power running control in the running mode I (see FIG. 5) when the battery voltage Vb of the high voltage battery 24 is high is performed.

  That is, in step S4, the first converter 31 is set in the first direct connection state (duty 0 [%] for both PWM signals P1 and P2), and the power from the battery voltage Vb of the high-voltage battery 24 is supplied to the second converter via the diode D1. 32 are supplied directly and continuously between the wirings 28 on the input side. In step S5, the ECU 40 calculates the drive torque of the motor 20 based on the operation of an accelerator pedal (not shown), and sets the target power (motor current Im and motor voltage Vm) so that the required motor power for generating the drive torque is obtained. The duty of PWM signals P3 and P4 of the second converter 32 is determined with reference to the battery voltage Vb.

  As described above, in the power running control in the traveling mode I, the electric power of the high voltage battery 24 is supplied to the input side of the second converter 32 via the first converter 31 (diode D1) that is controlled to be in the direct connection state. Converter 32 controls motor voltage Vm according to the required torque of motor 20. Since the first converter 31 is not switched, power loss can be reduced.

  On the other hand, when the determination in step S3 is affirmative (step S3: YES), in the steps S6 and S7, control is performed at the time of SOC decrease in the travel mode V when the battery voltage Vb of the high voltage battery 24 is low. .

  In the control at the time of lowering of the SOC, for the convenience of understanding, the process of step S7 will be described first. In order to make the switching loss of the second converter 32 zero, the PWM of the upper arm element UM2 of the second converter 32 is controlled. The duty of the signal P3 is set to 100 [%], and the duty of the PWM signal P4 of the lower arm element LM2 is set to 0 [%]. As a result, the second converter 32 is brought into the direct connection control state, and the line voltage V0 that is the input voltage of the inverter 22 is supplied between the DC terminals 26a and 26b of the inverter 22 through the transistor Q3 in the on state. At this time, in step S6, the first converter 31 boosts the battery voltage Vb of the high-voltage battery 24 in accordance with the required torque of the motor 20, and controls the motor voltage Vm. That is, in the SOC decrease control in the running mode V, the operation is performed so that the voltage decrease of the high voltage battery 24 is compensated by the boost operation of the first converter 31.

  If it is determined in step S2 described above that the engine is in the regenerative state (step S2: YES), regeneration control of the motor 20 in the travel mode VI is performed in steps S8 and S9. At this time, the duty of the PWM signals Puu, Puv, Puw, Plu, Plv, and Plw of the inverter 22 are all 0 [%]. For convenience of understanding, the regenerative power is described as follows from the process of step S9. In order to fully charge (remove) the high-voltage battery 24, the second converter 32 is set in a directly connected state (duty 0 [%] of P3 and P4), and in step S8, the first converter 31 is directly connected (P1). , The motor current Im that is a regenerative current flowing from the motor 20 is passed through the reactor Rb, the diode D3, the transistor Q1, and the reactor Ra. The high voltage battery 24 is charged. Since both the first and second converters 31 and 32 are not switched, the generation of power loss can be minimized.

  The contactors S1 and S2 are in an off state (open state) during the above-described steps S1 to S9.

  Next, in step S10, the ECU 40 executes power supply control processing according to the travel modes II, III, and IV.

  In this case, in step 10a shown in FIG. 4, the electric vehicle 10 is traveling whether or not the power supply mode in which the electric vehicle 10 is supplied with power from the overhead line L is in a state that can be turned on. Whether the road is a road where the overhead line L is provided or whether the section where the electric vehicle 10 is traveling is a section where the overhead line L is provided is determined.

  When the determination in step S10a is affirmative (step S10a: YES), it is estimated that the charging operation of the high-voltage battery 24 is started without delay. Therefore, in step S10b, the second converter 32 The motor voltage Vm corresponding to the required torque of the motor 20 is controlled by the electric power.

  Next, in step S10c, a precharge process for the capacitor C1, which is a process “immediately before feeding” in the travel mode II, is performed.

  When the overhead wire contact terminal CT of the electric vehicle 10 transitions from the separated state from the overhead wire L to the contact state, an excessive inrush current flows through the capacitor C1 and the high-voltage battery 24, which are smoothing capacitors having a large capacitance, and the capacitor C1 and In order to prevent the high-voltage battery 24 from deteriorating, the first intensification is performed until the potential difference between the line voltage V0 of the wiring 28 and the overhead wire feeding voltage Vh is within a predetermined voltage difference for the purpose of limiting the inrush current. The converter 31 is operated to boost the line voltage V0 (in practice, the first converter 31 is boosted so that the line voltage V0 becomes a voltage corresponding to the overhead line power supply voltage Vh).

  Next, in step S10d, the power receiving arm AM is deployed. As a result, the power receiving arm AM starts to extend or tilt.

  Next, in step S10e, whether or not the overhead wire contact terminal CT at the tip of the power receiving arm AM is in contact with the overhead wire L is determined using a proximity sensor (not shown) or the like.

  When the determination in step S10e becomes affirmative (step S10e: YES), in step 10f, the power feeding contactor S is changed from the off state (open state) to the on state (closed state). Thereby, the line voltage V0 becomes the overhead line feeding voltage Vh which is the voltage of the overhead line L (V0 = Vh).

  Next, in step S10g, the ECU 40 executes a “power supply initial stage” control process in the travel mode III.

  In this “power supply initial” control, when the overhead wire contact terminal CT of the electric vehicle 10 transitions from the separated state from the overhead wire L to the contact state, the capacitor C1 and the high voltage battery 24 are prevented from deteriorating. More specifically, the excessive inrush current flowing through the battery 24 is limited. In other words, the increase amount (time change amount ΔIb / Δt) of the battery current Ib, which is the charging current, is limited so as not to exceed a predetermined increase amount (threshold increase amount). In other words, the charge amount SOC of the high voltage battery 24 is set while applying a so-called rate limit so that the battery current Ib, which is the charging current flowing from the overhead line L to the high voltage battery 24 via the overhead line contact terminal CT, gradually increases. It is increased until the determination in S10h becomes affirmative (the difference between the line voltage V0 and the battery voltage Vb is within a predetermined value).

  In step S10h, when the difference between the line voltage V0 and the battery voltage Vb is within a predetermined value (step S10h: YES), the first converter 31 is in a directly connected state (P1 duty 100 [%], P2 Even if the duty is 0 [%]), it is determined that an excessive inrush current does not flow through the high-voltage battery 24. In step S10i, the first converter 31 is directly connected and is not switched, thereby increasing the charging efficiency. Then, the charging of the high voltage battery 24 is continued.

  In step S10j, whether or not the high voltage battery 24 is in a predetermined fully charged state is determined based on the charge amount SOC. When the high voltage battery 24 is in a fully charged state (step S10j: YES), in step S10k, a power contactor is supplied. S1 and S2 are shifted from the on state (closed state) to the off state (open state).

  Next, in step S101, the power receiving arm AM is contracted or tilted in the reverse direction and stored in a predetermined position of the electric vehicle 10.

  In this way, the power supply control during traveling is terminated, and the process returns to step S1. In step S10a, when the power supply mode of the electric vehicle 10 is not in a state that can be turned on (step S10a: NO), the power supply control flow from step S10a to step S101 is skipped and stepped. Return to S1.

  Next, an example of the relationship between the transition of the driving modes I to VI of the electric vehicle 10 and each physical quantity will be described with reference to the time chart of FIG.

  For convenience of understanding, it is assumed that the motor power Pm is controlled to a positive constant value during power running and is controlled to a negative constant value during regeneration. Similarly, the voltage sensor 34 is used during power running and regeneration. In the following description, it is assumed that the detected motor voltage Vm is controlled to a constant value.

  At the time of “powering” control in the traveling mode I (contactors S1, S2: off state) between the time points t0 and t1, the first converter 31 is controlled to be in the direct connection state. Since the battery voltage Vb and the line voltage V0 are decreased and the motor power Pm is held constant by the inverter 22, the battery current Ib as the discharge current and the second converter 32 are supplied to the second converter 32 according to the decrease in the charge amount SOC. The input current I0 increases.

  During the “immediately before power supply” control in the driving mode II between the time points t1 and t2, that is, immediately before the contact between the overhead wire contact terminal CT of the electric vehicle 10 and the overhead wire L, an excessive inrush current does not flow through the capacitor C1. The voltage across the capacitor C1, that is, the line voltage V0 is gradually increased to the vicinity of the overhead line power supply voltage Vh (the capacitor C1 is precharged). Since the motor power Pm is in a constant power running state between the time points t1 and t2, the input current I0, the charge amount SOC, the battery voltage Vb, and the battery current Ib also gradually decrease.

  At time t2, the power receiving arm AM is deployed, and the overhead wire contact terminal CT is brought into contact with the overhead wire L. At the time of “power supply initial” control in the traveling mode III between the time points t2 and t3, the battery voltage Ib, which is a charging current, is controlled by the first converter 31 so as to gradually increase, and the battery voltage Vb and the overhead wire power supply voltage Vh are When the battery voltage Vb increases until the difference between them becomes within a predetermined value, the first converter 31 is brought into a directly connected state (P1 duty 100 [%], P2 duty 0 [%]) (time point t3).

  At the time of “power feeding” control in the driving mode IV between the time points t3 and t4, rapid charging is performed, and when the charge amount SOC of the high-voltage battery 24 becomes fully charged (time point t4), the contactors S1 and S2 are turned on. The charging is terminated by making a transition to the off state from the power supply, and the power receiving arm AM is also housed.

  Note that the external power supply 12 is set to a constant voltage when charging the high-voltage battery 24 from the time t2 to t4 by external power supply (bat charge), but the overhead power supply voltage Vh is varied in order to make the external power supply device 12 constant power. You may make it make it.

  Hereinafter, at the time t5 during the “powering” control in the traveling mode I (first converter 31: direct connection, second converter 32: Vm control) between the time points t4 and t5, the charge amount SOC becomes a value equal to or less than the threshold SOCth. At time t5 to t6, control is performed at the time of SOC reduction in the travel mode V (first converter 31: Vm control, second converter 32: direct connection), and the motor power Pm is maintained to maintain the torque. Therefore, the line voltage V0 is increased and held by the first converter 31.

  At the time of “regeneration” control in the travel mode VI from time t6 to time t7, the first and second converters 31 and 32 are both directly connected, and the battery voltage Vb and the charge amount SOC increase.

[Summary of Embodiment]
As described above, the electric vehicle 10 according to the above-described embodiment is an inverter that converts power supplied from the high-voltage battery 24 serving as a vehicle-mounted power storage device and / or power supplied from the overhead wire L through the vehicle-mounted overhead wire contact terminal CT. This is converted by 22 and supplied to the motor 20 for driving the vehicle.

  In this case, the first converter 31 provided between the positive and negative terminals of the high-voltage battery 24 and the overhead wire contact terminal CT, and the second converter 31 provided between the overhead wire contact terminal CT and the DC terminals 26a and 26b of the inverter 22; ECU 40 for controlling the first and second converters 31 and 32, and the ECU 40 applies the voltage applied to the inverter 22 (DC voltage V 0) of the motor 20 during power feeding from the overhead line L through the overhead line contact terminal CT. The charge amount SOC in which the voltage of the high voltage battery 24 is equal to or higher than a predetermined voltage is controlled by the threshold charge amount when the second converter 32 is controlled so as to correspond to the required power and the overhead line contact terminal CT is separated from the overhead line L. In the case of SOCth or higher (step S3: NO), the first converter 31 is controlled to be in a directly connected state (step S4) and the second converter 32 is controlled so that the motor voltage Vm, which is the voltage applied to the inverter 22, corresponds to the required power of the motor 20 (step S5), while the charge amount SOC in which the voltage of the high-voltage battery 24 is less than the predetermined voltage is If it is less than the threshold charge amount SOCth (step S3: YES), the first converter 31 is controlled such that the motor voltage Vm, which is the voltage applied to the inverter 22, corresponds to the required power of the motor 20 (step). Along with S6), the second converter 32 is controlled to be in a directly connected state (step S7).

  According to this embodiment, in addition to the first converter 31 that boosts the battery voltage Vb of the high-voltage battery 24 to the equivalent of the overhead line power supply voltage Vh, the power of the overhead line supply voltage Vh that is in contact with the overhead line L and is increased from the overhead line L Since the second converter 32 is provided between the receiving wire contact terminal CT and the DC terminal 26 of the inverter 22 that drives the motor 20, the second converter 32 is applied even when the overhead wire feeding voltage Vh, which is a high voltage, is applied from the overhead wire L. 32 becomes an electric shock absorber, and application of a high voltage to the inverter 22 is avoided.

  As a result, heat generation of the inverter 22 can be suppressed, and an appropriate voltage lower than the high voltage can be applied to the inverter 22 and the motor 20 via the second converter 32.

  In this case, when the ECU 40 makes a transition from the state where the overhead wire contact terminal CT is separated from the overhead line L to the contact state, the ECU 40 sets the first voltage so that the voltage between the overhead wire contact terminals CT becomes a voltage equivalent to the overhead wire feeding voltage Vh. The converter 31 performs step-up control of the battery voltage Vb (step S10c), and the second converter 32 performs control so that the voltage applied to the inverter 22 corresponds to the required power of the motor 20 (step S10b). Generation of a large inrush current can be prevented when the overhead wire contact terminal CT contacts with. Further, it is not necessary to limit the required power of the motor 20 when the overhead wire contact terminal CT contacts the overhead line L.

  Note that when the ECU 40 makes a transition from a state where the overhead wire contact terminal CT is separated from the overhead line L to a contact state, the charging current to the high voltage battery 24 supplied via the first converter 31 through the overhead line L is increased. After controlling the first converter 31 so as to gradually increase (step S10g), when the potential difference between the input and output of the first converter 31 falls within a predetermined value (step S10h: YES), the first converter 31 is directly connected. (Step S10i), the switching loss can be reduced, and the efficiency of charging the high voltage battery 24 from the external power supply device 12 through the overhead line L, the power receiving arm AM, the contactor S, and the first converter 31 is increased. Can do.

  Further, the ECU 40 controls the first and second converters 31 and 32 to be in a directly connected state (steps S8 and S9) when the motor 20 is regenerated (step S2: YES). Loss can be reduced and regenerative power can be recovered more efficiently.

  Thus, according to this embodiment, since the second converter 32 is provided between the overhead wire contact terminal CT and the DC terminal 26 of the inverter 22, a high voltage as in the electric railway field is applied from the overhead wire L. Even if it is done, it becomes possible to apply an appropriate voltage lower than the high voltage to the motor 20 and the inverter 22 that supplies electric power to the motor 20, thereby preventing the inverter 22 from generating heat, as well as the inverter 22 and the motor 20 Can be miniaturized.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the description of this specification.

DESCRIPTION OF SYMBOLS 10 ... Electric vehicle 12 ... External power supply device 14 ... Vehicle electric power feeding traffic system 20 ... Motor 22 ... Inverter 24 ... High voltage battery 31 ... 1st DC / DC converter (1st converter)
32. Second DC / DC converter (second converter)
AM ... Receiving arm CT ... Overhead contact terminal L ... Overhead wire

Claims (4)

In an electric vehicle that converts electric power supplied from an in-vehicle power storage device and / or electric power supplied from an overhead line through an in-vehicle overhead line contact terminal by an inverter and supplies the electric power to a vehicle driving motor.
A first DC / DC converter provided between a terminal of the power storage device and the overhead wire contact terminal;
A second DC / DC converter provided between the overhead wire contact terminal and the inverter terminal;
A controller for controlling the first and second DC / DC converters,
The controller is
Controlling the second DC / DC converter so that the voltage applied to the inverter corresponds to the required power of the motor during power feeding from the overhead wire through the overhead wire contact terminal;
If the voltage of the power storage device is greater than or equal to a predetermined voltage when the overhead wire contact terminal is separated from the overhead wire, the first DC / DC converter is controlled to be in a directly connected state and the second DC / DC converter Is controlled so that the voltage applied to the inverter corresponds to the required power of the motor, and when the voltage of the power storage device is less than the predetermined voltage, the first DC / DC converter is connected to the inverter. The electric vehicle is controlled so as to correspond to the required power of the motor, and the second DC / DC converter is controlled to be in a directly connected state. The electric vehicle according to claim 1,
The controller is
When transitioning from the state where the overhead wire contact terminal is separated from the overhead wire to the contact state,
The first DC / DC converter is controlled so that the voltage between the overhead wire contact terminals becomes a voltage corresponding to the overhead wire feeding voltage, and the second DC / DC converter has a voltage applied to the inverter to a required power of the motor. An electric vehicle characterized by being controlled to respond. The electric vehicle according to claim 2,
The controller is
When the overhead wire contact terminal is separated from the overhead wire to a contact state, a charging current to the power storage device supplied via the first DC / DC converter gradually increases through the overhead wire. After controlling the first DC / DC converter as described above, when the potential difference between the input and output of the first DC / DC converter falls within a predetermined value, the first DC / DC converter is controlled to be in a directly connected state. Electric car. The electric vehicle according to any one of claims 1 to 3,
The controller is
An electric vehicle characterized in that the first and second DC / DC converters are controlled to be in a directly connected state during regeneration of the motor.

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