JP5350843B2 - Power supply control device and power supply control method - Google Patents

Description

  The present invention relates to a power supply control device and a power supply control method, and more particularly to a power supply control device including a charge / discharge control device that includes a buck-boost chopper and controls charge / discharge of a storage battery mounted on an electric vehicle, and a control method thereof.

  A conventional railway vehicle receives electric power from an overhead line laid in the air via a pantograph attached to the upper part of the vehicle, and travels by driving a motor with the electric power. In recent years, railway vehicles have been developed that can travel not only in sections where overhead lines are laid (hereinafter referred to as “overhead section”) but also in sections where overhead lines are not laid (hereinafter referred to as “overhead-less section”). (For example, refer to Patent Document 1). Such a vehicle has a storage battery inside and travels in an overhead line-less section using electric power stored in the storage battery. In such a vehicle, charging of the storage battery is performed by taking in electric power from the overhead line via the pantograph while traveling in the overhead line section or at a predetermined charging station provided in the overhead line-less section. Alternatively, the storage battery is also charged by regenerative power generated during the braking operation of the vehicle.

  In general, since the overhead wire voltage and the storage battery voltage are different, when charging the storage battery from the overhead wire, it is necessary to convert the overhead wire voltage into a predetermined voltage and perform charging with the converted voltage. The same applies to charging with regenerative power. In addition, since the voltage of the storage battery varies depending on the state of charge, the output voltage of the storage battery is converted to a constant voltage when power is supplied from the storage battery to a load such as a motor or auxiliary machine (that is, when the storage battery is discharged). There is a need to. For this reason, conventionally, the charge / discharge control apparatus was provided for charge and discharge control of a storage battery (for example, refer patent document 2).

  In FIG. 4, the structure of the charging / discharging control apparatus disclosed by patent document 2 is shown. As shown in FIG. 4, the charge / discharge control device 100 of Patent Document 2 includes a bidirectional buck-boost chopper 1 </ b> A and a control unit 2. The bidirectional buck-boost chopper 1A includes a first switching element SW1, a second switching element SW2 having one main terminal connected to one main terminal of the first switching element SW1, and a third switching element. SW3, a fourth switching element SW4 having one main terminal connected to one main terminal of the third switching element SW3, one main terminal of the first switching element SW1, and a third switching element SW3 And a diode D1 to D4 connected in parallel to the first to fourth switching elements SW1 to SW4, respectively.

  In the charge / discharge control apparatus of Patent Document 2, the power supply side arm including the first switching element SW1 and the second switching element SW2, the third switching element SW3, and the fourth switching element are charged and discharged. Control is performed so that at least one of the modulation rate (flow rate) of the battery side arm including SW4 becomes 1. With this configuration, the switching element of the arm having the modulation rate (conduction rate) of 1 is always ON or always OFF, so that the switching loss can be reduced.

JP 2001-352607 A JP 2008-228420 A

  However, the charge / discharge control device of Patent Document 2 operates the step-up / down chopper 1A both during charging and discharging of the storage battery. For this reason, conduction loss occurs in the reactor DCL and the switching elements SW1 to SW4 included in the step-up / down chopper 1A. Furthermore, switching loss and electromagnetic noise accompanying switching occur with the switching operation of the switching elements SW1 to SW4. This switching noise may affect other signals.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power supply control device and a power supply control method capable of reducing power loss and noise in a buck-boost chopper. .

A power supply control device according to the present invention is a power supply control device that controls charging / discharging of a storage battery mounted on an electric vehicle, and includes a step-up / step-down chopper that performs voltage conversion by switching operations of a plurality of switching elements. A charge / discharge control device for controlling charge / discharge and a first node on the storage battery side and a second on the overhead wire side in the high-voltage side bus of the buck-boost chopper when turned on and connected in parallel to the charge / discharge control device A bypass circuit that bypasses the charge / discharge control device to enable charging / discharging of the storage battery by short-circuiting the node, and that bypasses the bypass path when turned off.

The power supply control method according to the present invention is a control method for a power supply control device that includes a step-up / step-down chopper that performs voltage conversion by switching operations of a plurality of switching elements, and that controls charging / discharging of a storage battery mounted on an electric vehicle. The control method is such that when traveling in an overhead wire-less section, the motor is driven by the voltage discharged from the storage battery of the electric vehicle so that the step-up / step-down chopper is not operated during traveling and the high-pressure side of the step-up / step-down chopper is controlled. in bus, and the first node in the storage battery side, by short-circuiting the second node on the overhead wire side, to form a bypass path which bypasses the buck chopper, battery charge and discharge through the bypass path I do. If the electric vehicle travels through the overhead line section, by driving the motor at a voltage received from overhead wires, traveling blocks the bypass path.

  The above-mentioned electric vehicle preferably travels by obtaining power from the overhead line to the vehicle in the overhead line section and charges the mounted storage battery, and in the overhead line-less section, the battery drive that can travel with the power charged in the mounted storage battery It is a vehicle.

  According to the present invention, the bypass battery bypasses the charge / discharge control device (step-up / step-down chopper) and enables the storage battery to be charged / discharged. As a result, the storage battery can be charged / discharged without operating the charge / discharge control device (step-up / step-down chopper), so that it is possible to reduce the conduction loss and switching loss of the reactor and switching element, which have conventionally occurred in the step-up / step-down chopper In addition, generation of switching noise can be prevented.

1 is a configuration diagram of a battery-powered vehicle including a power control device according to an embodiment of the present invention. Detailed configuration diagram of charge / discharge controller The figure which showed the SOC characteristic which shows the voltage change with respect to SOC (state of charge) in various batteries etc. The figure which showed the structure of the conventional charge / discharge control apparatus

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

1. Configuration FIG. 1 is a diagram showing a configuration of a battery-powered vehicle equipped with a power supply control device according to an embodiment of the present invention. In FIG. 1, the battery-powered vehicle 1 is composed of a three-car train. A main control device (VVVF inverter) 65 for driving the motor 60 is mounted on the vehicle A, and a pantograph 5 for taking in electric power from the overhead line 3 is provided on the vehicle B. In the vehicle C, a power supply control device 10 that controls the supply of power to a load including a motor 60 and auxiliary equipment (such as cabin lights, heaters, coolers, and broadcasting facilities in the vehicle), and electric power are stored. A storage battery 20 is mounted to supply power to the load when power cannot be received. In addition, a battery drive vehicle means the electric vehicle carrying the battery which drive | works only an overhead wire area, an overhead wire-less area, or an overhead wire-less area. The battery-powered vehicle is driven by a battery, but may be further driven by electric power from an overhead line, a diesel engine, or the like.

  The main controller 65 converts the DC voltage from the overhead wire 3 into a three-phase AC voltage having a desired frequency and voltage, and supplies the three-phase AC voltage to the motor 60 to drive the motor 60.

  The storage battery 20 is formed of a secondary battery that can obtain an output voltage sufficient to drive the motor 60. Moreover, it is preferable that the storage battery 20 is comprised with a secondary battery with a small fluctuation range of an output voltage. An example of such a battery is a nickel metal hydride battery. As will be described later, the nickel-metal hydride battery has a characteristic that the voltage fluctuation range is small regardless of the state of charge (SOC). The storage battery 20 is a secondary battery other than a nickel metal hydride battery as long as an output voltage sufficient to drive the motor 60 is obtained and the output fluctuation range is within the allowable range in the specification. It may be configured. In the present embodiment, the storage battery 20 is assumed to be a nickel metal hydride battery.

  The power supply control device 10 includes a charge / discharge control device 11, a bypass circuit 12, an auxiliary power supply device 13, and a diode 15. The auxiliary power supply device 13 controls the supply of power to auxiliary equipment such as cabin lights, heaters, coolers, and broadcasting facilities in the vehicle.

  The bypass circuit 12 is connected in parallel with the charge / discharge control device 11. When the bypass circuit 12 turns on and becomes conductive, the node X and the node Y on the high-voltage side bus of the step-up / step-down chopper 33 are short-circuited to form a bypass path for the step-up / step-down chopper 33. When the bypass circuit 12 is turned off, the bypass path between the node X and the node Y is blocked (opened). That is, the bypass circuit 12 bypasses the charge / discharge control device 11 (the step-up / down chopper 33) and forms a bypass path that allows charging or discharging from the storage battery 20.

  The bypass circuit 12 can be configured by a contactor or a semiconductor switch that can conduct in both directions. The semiconductor switch can be composed of, for example, a semiconductor element such as a single unit or a pair of triacs, MOSFETs, GTOs, and IGBTs. The semiconductor element preferably has a small conduction loss.

  The charge / discharge control device 11 controls charging to the storage battery 20 and discharging from the storage battery 20. The charge / discharge control device 11 and the bypass circuit are connected to the overhead wire 3 side via a high-speed circuit breaker 37.

  FIG. 2 shows a detailed configuration of the charge / discharge control device 11 and its peripheral circuits. The charge / discharge control device 11 includes a step-up / down chopper 33. The step-up / step-down chopper 33 has a function of increasing or decreasing the voltage received from the overhead wire 3 or the storage battery 20 to a desired voltage.

  As shown in FIG. 2, the step-up / down chopper 33 includes a half bridge formed of a series circuit of a first switching element 41 and a second switching element 42 provided on the storage battery 20 side, and a first bridge provided on the overhead line 3 side. A half bridge composed of a series circuit of the third switching element 43 and the fourth switching element 44, a connection point of the first switching element 41 and the second switching element 42, and the third switching element 43 and the fourth switching element. And a reactor 45 connected between 44 connection points. Diodes 41d to 44d are connected in antiparallel to the first to fourth switching elements 41 to 44, respectively. Each switching element 41-44 is comprised, for example by IGBT. The circuit configuration of the step-up / step-down chopper 33 shown in FIG. 2 is the same as the circuit configuration of the bidirectional step-up / step-down chopper disclosed in Patent Document 2, and the operation thereof is also disclosed in Patent Document 2. Therefore, description of the basic step-up / step-down operation of the step-up / step-down chopper 33 is omitted here. The configuration of the step-up / step-down chopper shown in the present embodiment is an example, and the circuit configuration of the step-up / step-down chopper may be another configuration.

  The control unit 35 controls the switching operation of the switching elements 41 to 44 of the buck-boost chopper 33 and the on / off of the bypass circuit 12.

  The charge / discharge control device 11 further includes filter capacitors 51f and 52f and filter reactors 51l and 52l for removing a pulsating flow component of the power source, and snubber capacitors 51s and 52s for suppressing a surge voltage.

2. Operation The battery-powered vehicle 1 of the present embodiment is a vehicle that can travel in both the overhead line section and the overhead line-less section. In the battery-powered vehicle 1 according to the present embodiment, the bypass circuit 12 is turned on and the storage battery 20 is directly connected to the main control device 65 and the auxiliary power supply device 13 without going through the charge / discharge control device 11 when traveling in an overhead line-less section. On the other hand, when traveling over the overhead line section, the bypass circuit 12 is turned off, and the storage battery 20 is connected to the main control device 65 and the auxiliary power supply device 13 via the charge / discharge control device 11. Hereinafter, the operations in the overhead line section and the overhead line-less section will be described in detail.

2.1 Operation during traveling in an overhead line-less section Since the battery-powered vehicle 1 cannot receive power from the overhead line 3 while traveling in an overhead line-less section, the battery-driven vehicle 1 uses the power stored in the storage battery 20. Drive the load. At that time, the bypass circuit 12 is turned on to conduct, and a bypass path for the step-up / step-down chopper 33 is formed. At that time, the step-up / step-down chopper 33 is stopped by turning off all the switching elements 41 to 44. Thereby, the electric power from the storage battery 20 is directly supplied to the main control device 65 and the auxiliary power supply device 13 via the bypass circuit 12. Note that this is possible because the voltage fluctuation of the storage battery 20 is small and the input voltage range of the main controller 65 and the auxiliary power supply device 13 is designed to be within the voltage fluctuation range of the storage battery 20. by.

  The charging voltage is directly supplied to the storage battery 20 via the bypass circuit 12 at the time of charging from a charging station having a charging control function in an overhead line-less section or charging of regenerative power from the main controller 65.

  As described above, during traveling without an overhead wire, the storage battery 20 is charged / discharged via the bypass circuit, and the step-up / down chopper 33 is not operated. For this reason, it is possible to reduce the conduction loss and switching loss of the reactor 45 and the switching elements 41 to 44 generated during the operation of the step-up / step-down chopper 33 and electromagnetic noise accompanying switching.

  It should be noted that there is a timing at which the bypass circuit 12 is turned on. If the bypass circuit 12 is turned on in a state where there is a large voltage difference between the voltage on the storage battery 20 side and the voltage on the overhead line 3 side, a large current flows instantaneously, and the circuit elements in the step-up / down chopper 33 are destroyed. is there. In order to prevent this, the bypass circuit 12 is configured such that the voltage at the node X (voltage on the overhead wire 3 side) of the high-voltage side bus of the step-up / down chopper 33 becomes equal to the voltage at the node Y (voltage of the storage battery 20). To turn on. Specifically, the modulation rate (flow rate) of the first and third switching elements 41 and 43 is 1, and the modulation rate (flow rate) of the second and fourth switching elements 42 and 44 is 0. (That is, when the voltage at the node X (voltage on the overhead wire 3 side) and the voltage at the node Y (voltage of the storage battery 20) become the same), the bypass circuit 12 is turned on. Then, after the bypass circuit 12 is turned on, all the first to fourth switching elements 41 to 44 of the step-up / step-down chopper 33 are turned off. Note that the modulation factor (conduction rate) of the switching element takes a value of 0 to 1, with 0 corresponding to always off and 1 corresponding to always on.

2.2 Operation during traveling in the overhead line section During traveling in the overhead line section, the bypass circuit 12 is turned off to open the bypass route.

  During traveling in the overhead line section, the battery-powered vehicle 1 is supplied with electric power from the overhead line 3 via the pantograph 5. The power supply control device 10 supplies the power received via the pantograph 5 to the main control device 65, the auxiliary power supply device 13, and the charge / discharge control device 11. When the overhead line voltage decreases, the power from the storage battery 20 is converted into desired power by the step-up / step-down chopper 33 of the charge / discharge control device 11, and then supplied to the main control device 65 and the auxiliary power supply device 13.

  The regenerative power generated at the time of braking is converted into a predetermined charging voltage by the step-up / step-down chopper 33 of the charging control device 11 and supplied to the storage battery 20 to charge the storage battery 20.

  As described above, the bypass circuit 12 is turned off during traveling of the overhead line section. However, what should be noted here is the timing of turning the bypass circuit 12 from on to off when the section moves from the overhead line-less section to the overhead line section. . As described above, the operation of the step-up / down chopper 33 is stopped in the section without the overhead wire. Therefore, after setting the modulation factors (conduction rates) of the first and third switching elements 41 and 43 of the step-up / down chopper 33 to 1, the bypass circuit is turned off and the modulation factors (conduction rates) of the switching elements 41 to 44 are set. The rate) is controlled to a command value from 1 to 0, and energization of the auxiliary power supply device (auxiliary machine) 13 via the charge / discharge control device is started. Then raise the pantograph.

3. In the other power supply control device 10, a diode 15 is provided on the high-voltage input end side of the charge / discharge control device 11. The diode 15 has a function of preventing discharge from the storage battery 20 to the overhead line 3 when the voltage of the storage battery 20 becomes higher than the voltage of the overhead line 3.

4). Supplement The following describes the characteristics of the nickel-hydrogen battery to be used as a battery 20. FIG. 3 shows SOC characteristics indicating voltage change with respect to SOC (state of charge) in various batteries and the like. Curve a shows the voltage change of the nickel metal hydride battery, curve b shows the voltage change of the lead acid battery, curve c shows the voltage change of the lithium ion battery, and curve d shows the voltage change of the electric double layer capacitor. From the figure, the ratio of voltage change (ΔV / ΔSOC) to SOC fluctuation is about 0.1 for nickel metal hydride battery, about 1.5 for lead acid battery, about 2 for lithium ion battery, and about 3 for electric double layer capacitor. It has become. In other words, if the voltage change (ΔV) is the same, the volume of the nickel-metal hydride battery can be reduced to 1/15 of the lead storage battery, 1/20 of the lithium ion battery, and 1/30 of the electric double layer capacitor.

  As shown in FIG. 3, the nickel metal hydride battery indicated by the curve a has a characteristic that the SOC range (range S) with respect to voltage fluctuation is wider than other batteries and the like. In other words, the nickel metal hydride battery has a characteristic that the battery voltage fluctuation is small relative to the SOC fluctuation. On the other hand, in other batteries indicated by the curves b, c, d, the battery voltage varies greatly with respect to the SOC. For example, in terms of the median SOC, in a nickel metal hydride battery, when the median voltage is V1 and the voltage fluctuation is within the range dV1, it can be used in almost all of the SOC range S. The battery capacity can be used effectively. On the other hand, when the lead-acid battery is used so that the median voltage is V2 and the voltage fluctuation is kept within dV2, it can be used only in a narrow range of SOC, and the battery capacity is effectively utilized. Can not. Similarly, when using a lithium ion battery so that the median voltage is V3 and the voltage fluctuation is within the range dV3, the battery can be used only in a narrow range, and the battery capacity is effectively utilized. Can not. Note that the magnitude of the voltage fluctuation range is dV1 / V1 = dV2 / V2 = dV3 / V3.

  As described above, since the nickel metal hydride battery can obtain a stable output voltage with a small fluctuation range compared to other batteries or the like, the storage battery 20 is connected to the main controller 65 via the bypass circuit 12 as in this embodiment. It becomes possible to connect directly to.

5. Summary In the conventional charge / discharge control device, it is necessary to perform voltage conversion by operating the step-up / step-down chopper in discharging from the storage battery during power running and charging to the storage battery during regeneration during traveling in an overhead line-less section. On the other hand, in the present embodiment, during traveling without an overhead wire, the charge / discharge control device 11 (that is, the step-up / step-down chopper 33) is not operated, and the discharge from the storage battery 20 during power running and the storage battery 20 during regeneration are performed. Can be charged. For this reason, the generation | occurrence | production of the electromagnetic noise accompanying the conduction loss of a reactor, the switching loss of a switching element, and the switching which occurred with the operation | movement of a step-up / step-down chopper can be reduced.

  According to the configuration of the present embodiment, even when the buck-boost chopper 33 fails, by turning on the bypass circuit 12 and providing a bypass path, the storage battery 20 can be charged / discharged without stopping the operation of the electric vehicle. It becomes possible to continue driving. This is a particularly great advantage when the electric vehicle is used for public transportation.

  In the present embodiment, the charge / discharge control device is operated in the overhead line section, but in the overhead line-less section, the power loss in the overhead line-less section is performed by charging / discharging the storage battery without operating the charge / discharge control device. To reduce power consumption as a whole. This is advantageous for an electric vehicle that can travel in both the overhead line section and the overhead line-less section.

DESCRIPTION OF SYMBOLS 1 Battery drive vehicle 3 Overhead line 5 Pantograph 10 Power supply control apparatus 11 Charging control apparatus 12 Bypass circuit 13 Auxiliary power supply control apparatus 15 Diode 20 Storage battery 33 Buck-boost chopper 35 Control part 37 High speed circuit breaker 60 Motor 65 Main control apparatus (VVVF inverter)

Claims (14)

A power supply control device for controlling charging and discharging of a storage battery mounted on an electric vehicle,
A charge / discharge control device that has a step-up / step-down chopper that performs voltage conversion by switching operations of a plurality of switching elements, and controls charge / discharge of the storage battery;
By short-circuiting the first node on the storage battery side and the second node on the overhead line side in the high-voltage side bus of the buck-boost chopper when connected to the charge / discharge control device in parallel and turned on , A bypass circuit that bypasses the charge / discharge control device to enable charging / discharging of the storage battery, and bypasses the bypass path when turned off; and
A power supply control device.   The power supply control device according to claim 1, wherein the storage battery is a nickel metal hydride battery. A control means for controlling the operation of the charge / discharge control device and the bypass circuit;
2. The power supply control device according to claim 1, wherein the control unit controls the bypass circuit so as to turn off the bypass circuit while the electric vehicle is running by driving a motor with electric power received from an overhead line. A control means for controlling operations of the step-up / step-down chopper and the bypass circuit;
The control means is configured to turn on the bypass circuit and not operate the step-up / step-down chopper and the step-up / step-down chopper while the electric vehicle is running by driving a motor with electric power discharged from the storage battery. The power supply control apparatus of Claim 1 which controls operation | movement of a bypass circuit. A control means for controlling operations of the step-up / step-down chopper and the bypass circuit;
The control means controls the step-up / step-down chopper and the bypass circuit to switch the bypass circuit from OFF to ON after making the voltage of the first node and the voltage of the second node the same. The power supply control device according to claim 1. A control means for controlling operations of the step-up / step-down chopper and the bypass circuit;
The control means controls the step-up / step-down chopper and the bypass circuit so as to switch the bypass circuit from ON to OFF after making the voltage of the first node and the voltage of the second node the same. The power supply control device according to claim 1.   The power supply control device according to claim 1, further comprising a diode inserted before the charge / discharge control device and the bypass circuit.   The electric vehicle travels by obtaining power from the overhead line to the vehicle in a section with an overhead line and charges the mounted storage battery, and in a section without the overhead line, a battery-driven vehicle that can travel with the power charged in the mounted storage battery The power supply control device according to claim 1, wherein   The power supply control device according to claim 1, wherein the bypass circuit is a semiconductor switch.   The power supply control device according to claim 1, wherein the bypass circuit is a contactor. A control method of a power supply control device that includes a step-up / step-down chopper that performs voltage conversion by switching operations of a plurality of switching elements, and that controls charging / discharging of a storage battery mounted on an electric vehicle,
While the electric vehicle is running by driving the motor with the voltage discharged from the storage battery, the electric vehicle is controlled so as not to operate the first step-up / down chopper, and the first high-voltage side bus of the step-up / down chopper is on the storage battery side. and nodes, by short-circuiting the second node on the overhead wire side, to form a bypass path which bypasses the buck chopper performs charging and discharging of the storage battery through the bypass path,
It said electric vehicle drives the motor with a voltage received from overhead wires, during running, blocking the bypass path,
Power control method. The power supply control method according to claim 11, wherein when the bypass path is newly formed, the bypass path is formed after making the voltage of the first node and the voltage of the second node the same. The power supply control method according to claim 11, wherein when the formed bypass path is cut off, the voltage of the first node and the voltage of the second node are made the same, and then the bypass path is cut off.   The electric vehicle travels by obtaining power from the overhead line to the vehicle in a section with an overhead line and charges the mounted storage battery, and in a section without the overhead line, a battery-driven vehicle that can travel with the power charged in the mounted storage battery The power supply control method according to claim 11, wherein

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