JP2013150525A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle having another route of supplying electric power from a battery to an auxiliary apparatus when a failure of an inverter and the like is detected and a main relay is opened.SOLUTION: A hybrid vehicle 2 includes: a first converter 17 which reduces a voltage of a battery 5 to an operating voltage of an auxiliary apparatus to output it; a switch 32 which switches connection destinations of an input terminal to either a charging connector 33 or the auxiliary apparatus; a charger 40 of which high voltage side terminal is connected to the battery and of which low voltage side terminal is connected to an input end of the switch, has a function of converting electric power impressed to the low voltage side terminal into electric power for charging the battery to output it to the high voltage side terminal and a function of converting a voltage of the battery impressed to the high voltage side terminal into an operating voltage of the auxiliary apparatus to output it to the low voltage side terminal; and a controller which opens a main relay 7, when a failure is detected, controls the switch 32 to connect the charger 40 and the auxiliary apparatus 19, and controls the charger 40 to output the voltage of the auxiliary apparatus.

Description

  The technology disclosed in this specification relates to an electric vehicle that can charge a battery (main battery) for driving a motor using an external power source. The “electric vehicle” in this specification includes a so-called plug-in hybrid vehicle that includes both a wheel driving motor and an engine, and can charge a motor driving battery using an external power source.

  The electric vehicle includes a main battery that supplies electric power for driving wheels, and an inverter that converts the electric power of the main battery into alternating current and outputs the alternating current to a motor. Since the main battery, inverter, and motor handle a large current, safety measures for the electric system are important in an electric vehicle. For example, Patent Document 1 proposes a technique in which a relay (system main relay) is interposed between a main battery and an inverter, and the relay is opened when an abnormality of the inverter is detected. The system main relay is a switch that connects or disconnects the main battery to the drive system. Note that “releasing the relay” means disconnecting the connection.

JP 2009-171769 A

  On the other hand, an electric vehicle includes a group of electric devices that operate at a voltage lower than the output voltage of the main battery, and usually supplies the electric power to the electric devices by stepping down the output voltage of the main battery. Examples of the electric device that operates at a voltage lower than the output voltage of the main battery include an air conditioner, a car audio, a navigation, a lamp, a wiper, and a power window. These are collectively referred to as “auxiliary equipment”. The converter that steps down the output voltage of the main battery and supplies it to the auxiliary machine is also connected to the downstream side of the current from the system main relay, so when the system main relay is opened, the power from the main battery to the auxiliary machine Supply will also stop. An electric vehicle also has a sub-battery (auxiliary battery) that supplies power to the auxiliary machine. However, if the capacity is small and the system main relay is opened, the auxiliary battery alone can supply power to the auxiliary machine for a long time. It cannot be supplied. The present specification provides an electric vehicle including another path for supplying power from a main battery to an auxiliary device when an abnormality of an inverter or a motor is detected and a system main relay is opened.

  The electric vehicle includes a charger that converts a voltage (electric power) supplied from an external power source into a voltage suitable for charging the main battery. Even so-called plug-in hybrid vehicles are equipped with a charger even in a hybrid vehicle that generates electric power with a motor using an engine. For the sake of explanation, the terminal on the side connected to the external power supply in the charger is referred to as a low voltage side terminal, and the terminal on the side connected to the main battery is referred to as a high voltage side terminal. The charger includes an AC / DC conversion circuit, a DC / AC conversion circuit, a booster circuit, a rectifier circuit, and the like as main circuits. Some of these circuits can also have a step-down function with the addition of a few electronic components. The technology disclosed in this specification uses a circuit of a charger and supplies power to an auxiliary machine via the charger when the system main relay is opened.

  The electric vehicle disclosed in this specification includes a wheel driving motor, a main battery, an inverter, a switch, a first converter, a second converter, and a controller. The first converter steps down the voltage of the main battery to the operating voltage of the auxiliary machine and outputs it. The second converter corresponds to the charger described above.

  In the second converter (charger), the high voltage side terminal is connected to the main battery, and the low voltage side terminal is connected to the auxiliary machine and the external power supply connector via the switch. Connected to the input terminal of the main battery, the function of converting the power applied to the low voltage side terminal to the power for charging the main battery and outputting it to the high voltage side terminal, and the main battery applied to the high voltage side terminal Is converted into the operating voltage of the auxiliary machine and output to the low voltage side terminal. When the controller detects an abnormality of the inverter or the motor, the controller opens the system main relay, controls the switch so as to connect the second converter and the auxiliary machine, and outputs the operating voltage of the auxiliary machine. To control the second converter. Note that the controller separates the second converter from the auxiliary equipment except when an abnormality is detected.

  When detecting the abnormality and opening the system main relay, the electric vehicle supplies power from the main battery to the auxiliary device via a route that passes through the switching device and the charger. Since a charger circuit is used for stepping down the output voltage of the main battery, the above mechanism can be realized at low cost.

  The switching device may be a device that selectively switches the connection destination of the low-voltage side terminal of the second converter to one of the auxiliary device and the external power supply connector. Typically, the switch has one input and two outputs, and the input terminal is connected to the low voltage side terminal of the second converter, and the low voltage side terminal is connected to the external power supply connector and the auxiliary device. It may be a device that selectively switches to any one of the above. Note that the switch has two contacts, and it is desirable to switch both the positive and negative connection destinations of the input end of the second converter. The “input terminal” and “output terminal” in the switch are simply terminology for the purpose of distinguishing the terminal on one side from the terminal on the other side, and specify the direction in which the current (or signal) flows. Note that this is not the case.

  Alternatively, the switch connects the first relay for connecting or disconnecting the auxiliary terminal to the low voltage side terminal of the second converter (charger), and the low voltage side terminal of the charger and the external power supply connector. Or a second relay that disconnects or disconnects. If the first relay is closed and the second relay is opened, the charger is connected to the auxiliary machine and is disconnected from the external power supply connector. Conversely, if the first relay is opened and the second relay is closed, the charger is disconnected from the auxiliary machine and connected to the external power supply connector. Furthermore, since the external power supply connector corresponds to an open end unless an external power supply is connected, the second relay may be closed while the external power supply is not connected.

  Details of the technology disclosed in this specification and further improvements will be described in the embodiments of the present invention.

It is a block diagram of the drive system of the hybrid vehicle of an Example. It is a flowchart figure of the process which a controller performs. It is an example of the circuit of a charger. It is a figure which shows the modification of a switch.

  An electric vehicle according to an embodiment will be described with reference to the drawings. The electric vehicle of an Example is the hybrid vehicle 2 provided with both a motor and an engine for driving | running | working. The hybrid vehicle 2 is a so-called plug-in type that includes a charger for charging a battery using an external power source such as a home AC power source.

  FIG. 1 shows a block diagram of a drive system of the hybrid vehicle 2. The hybrid vehicle 2 includes a motor 12 and an engine 16 as drive sources. The output torque of the motor 12 and the output torque of the engine 16 are appropriately distributed / combined by the power distribution mechanism 14 and transmitted to the axle 15.

  Electric power for driving the motor 12 is supplied from the main battery 5. The output voltage of the main battery 5 is 300 volts, for example. The main battery 5 is connected to the inverter 9 via the system main relay 7. The system main relay 7 is a switch that connects or disconnects the main battery 5 and the drive system of the vehicle. The system main relay 7 is switched by the controller 4.

  The inverter 9 boosts the voltage of the main battery 5 to a voltage suitable for driving the motor (for example, 600 volts), converts the DC power into AC power having a predetermined frequency, and supplies the AC power to the motor 12. The hybrid vehicle 2 can also generate electric power with the motor 12 using the driving force of the engine 16 or the deceleration energy of the vehicle. When the motor 12 generates power, the inverter 9 converts alternating current into direct current, further reduces the voltage to a voltage slightly higher than the main battery 5, and supplies the voltage to the main battery 5. The voltage slightly higher than the main battery 5 is, for example, within the rated output voltage of the main battery 5 plus 5 volts. Since the voltage output from the inverter 9 is slightly higher than that of the main battery 5, the main battery 5 is charged.

  The output of the main battery 5 is also sent to the voltage converter 17 via the system main relay 7. The voltage converter 17 is a step-down DCDC converter that steps down the output voltage (for example, 300 volts) of the main battery 5 to a voltage (for example, 12 volts) suitable for driving other electronic devices. Here, other devices, that is, devices operating at a voltage lower than the voltage for driving the motor 12 are collectively referred to as “auxiliary equipment”. Typical examples of auxiliary machines include an air conditioner 19, a headlight 20, a car navigation system 21 and the like. Various on-vehicle controller circuits (excluding parts through which motor drive current flows) are also included in the auxiliary equipment category because they operate at the same level of voltage as in car navigation systems. The controller 4 that generates a PWM signal that is a command to the inverter 9 and the voltage converter 17 is also included in the auxiliary machine category. In FIG. 1, a common power supply line that supplies power to the auxiliary machine is indicated by a symbol APL. The fact that the power supply line APL is interrupted in FIG. 1 indicates that another auxiliary device is connected to the power supply line APL in addition to the illustrated auxiliary device.

  An auxiliary battery 18 is also connected to the power supply line APL to the auxiliary machine. The output of the voltage converter 17 is connected to the power supply line APL. That is, the output terminal of the voltage converter 17 is connected in parallel to the auxiliary battery 18, and the output of the voltage converter 17 is also supplied to the auxiliary battery 18. The hybrid vehicle 2 charges the auxiliary battery 18 and supplies power to the auxiliary machine using the high output high capacity main battery 5 for driving the motor. The auxiliary battery 18 is provided for the purpose of supplying electric power to the auxiliary machine when it cannot receive power from the main battery 5 or the motor 12 as a generator.

  Note that the hybrid vehicle 2 actually has a large number of controllers provided for each function, and functions as a single vehicle system by the cooperation of the large number of controllers. However, in order to simplify the description in this specification, even if the controller is physically divided into a plurality of controllers, they are collectively referred to as “controller 4”.

  The hybrid vehicle 2 can charge the main battery 5 by receiving power supply from the external power source 91. The charging system includes the sub relay 31, the charger 40, the switch 32, and the external power supply connector 33 as main components. An external power supply connector 33 for connecting a plug 90 for supplying power from the external power supply 91 is connected to the charger 40 via the switch 32.

  The charger 40 has a function of converting the power of the external power source 91 into DC power suitable for charging the main battery 5. The external power supply 91 normally supplies power at a voltage lower than the output voltage of the main battery 5. Usually, the output voltage of the external power supply 91 is 100 volts to 200 volts. Therefore, the main battery 5 side terminal of the charger 40 is referred to as a high voltage side terminal TH, and the external power source 91 side terminal is referred to as a low voltage side terminal TL. The high voltage side terminal TH of the charger 40 is connected to the main battery 5 via the sub relay 31. The sub-relay 31 is provided to cut off between the main battery 5 and the external power source or auxiliary machinery group. The sub relay 31 is switched by the controller 4.

  The low voltage side terminal TL of the charger 40 is connected to the input terminals c1 and c2 of the switch 32. The switch 32 has 1 input and 2 outputs. The contacts c1 and c2 correspond to input ends, and the set of contacts a1 and a2 and the set of b1 and b2 correspond to output ends. However, the names “input end” and “output end” are for convenience to distinguish one terminal of the switch from the other terminal connected thereto, and current (or signal) flows. Note that it does not prescribe direction. The switching device 32 is a two-contact type (contacts c1 and c2), and switches the positive and negative electrodes of the charger 40 simultaneously. One output terminal a <b> 1, a <b> 2 of the switch 32 is connected to a connector 33 for connecting an external power source. The external power supply 91 and the vehicle 2 are physically connected by connecting the plug 90 of the external power supply 91 to the external power supply connector 33. The other output terminals b1 and b2 of the switch 32 are connected to the power supply line APL of the auxiliary machine. That is, the other output terminals b1 and b2 of the switch 32 are connected to the auxiliary machine. In addition to the function of converting the power input to the low voltage side terminal TL into DC power suitable for charging the main battery 5, the charger 40 converts the power of the main battery 5 input to the high voltage side terminal TH to It has a function of converting to the operating voltage of the auxiliary machine. When the controller 4 charges the main battery 5 with the external power supply 91 (when the plug 90 of the external power supply 91 is connected to the external power supply connector 33), the low voltage side terminal TL of the charger 40 is connected to the external power supply. The switch 32 is controlled so as to be connected to the connector 33.

  On the other hand, the controller 4 monitors whether or not an abnormality has occurred in the inverter 9 or the motor 12. For example, the controller 4 determines that an abnormality has occurred when the temperature of the inverter or the output current of the inverter is out of the allowable range. Although abnormality of an inverter and a motor is based on various sensor data, in this specification, such various sensors are collectively referred to as an inverter sensor 13a and a motor sensor 13b. Specific examples of the inverter sensor 13a and the motor sensor 13b are a temperature sensor, a current sensor, a voltage sensor, and the like. When the controller 4 detects an abnormality from the sensor data of the inverter sensor 13a and the motor sensor 13b, the controller 4 opens the system main relay 7 and connects the low voltage side terminal TL of the charger 40 to the auxiliary machine 32. To control. At the same time, the controller 4 controls the charger 40 so as to step down the voltage of the main battery 5 and output it from the low voltage side terminal TL.

  Processing of the controller 4 relating to abnormality detection of the inverter 9 and the motor 12 will be described. FIG. 2 shows a flowchart of processing executed by the controller 4. The process of FIG. 2 is started when the controller 4 detects some abnormality of the inverter or the motor based on the data of the inverter sensor 13a or the motor sensor 13b.

  First, the controller 4 determines from the sensor data of the inverter sensor 13a or the motor sensor 13b whether the vehicle is abnormal enough to continue traveling or is abnormal incapable of traveling (S2). Whether the type of abnormality is that the vehicle can continue traveling or cannot travel is predetermined for the sensor data and stored in the controller 4. For example, the controller 4 has a rule that when the temperature of the inverter 9 is between the first threshold temperature and the second threshold temperature, the inverter 9 is slightly overheated, but the motor output upper limit is lowered to continue running. When the temperature of the inverter 9 exceeds the second threshold value, the rule that the inverter 9 is severely heated and immediately stops traveling is described in advance. The controller 4 collates the stored rules with the sensor data, and determines whether or not the running can be continued. When it is determined that traveling cannot be continued (S2: NO), the controller 4 opens the system main relay 7 (S3). That is, the controller 4 disconnects the connection between the main battery 5 and the inverter 9. As shown in FIG. 1, when the system main relay 7 is opened, the power supply to the voltage converter 17 is also cut off. As a result, power supply to the auxiliary machine via the voltage converter 17 is stopped. At this time, it should be noted that since power is supplied to the auxiliary machine from the auxiliary battery 18, the power supply to the auxiliary machine does not stop.

  Next, the controller 4 controls the switching device 32 to switch the connection destination of the low voltage side terminal TL of the charger 40 from the contacts a1 and a2 to the contacts b1 and b2. That is, the low voltage side terminal TL of the charger 40 is connected to the auxiliary machine (S4). Next, the controller 4 closes the sub-relay 31 and connects the main battery 5 to the charger 40. The controller 4 drives the charger 40 so as to step down the voltage applied to the high voltage terminal TH (the output voltage of the main battery) to the operating voltage of the auxiliary machine and output it to the low voltage terminal TL (S6). . As a result, electric power is supplied from the main battery 5 to the auxiliary device not via the voltage converter 17 but via the charger 40 and the switch 32.

  As described above, the hybrid vehicle 2 of the embodiment can continue the power supply from the main battery 5 to the auxiliary device even when the system main relay 7 is opened. Note that the controller 4 controls the switch 32 and normally disconnects between the low voltage terminal TL of the charger 40 and the auxiliary device (while no abnormality is detected), and the abnormality is detected. Then, the low voltage side terminal TL and the auxiliary machine are connected.

  The charger 40 boosts the voltage applied to the low voltage side terminal TL and outputs it to the high voltage side terminal TH, and steps down the voltage applied to the high voltage side terminal TH to the low voltage side terminal TL. So-called bidirectional power conversion is provided. An example of the circuit configuration of such a charger 40 is shown in FIG. The charger 40 includes a coil L, an ACDC conversion circuit 41, a step-up / step-down circuit 42, a DCAC conversion circuit 43, a transformer Ts, and a rectifier circuit 44 from the low voltage side terminal TL toward the high voltage side terminal TH. Yes. Transistors included in each circuit are appropriately driven by the controller 4.

  An outline of the operation of the charger 40 when converting the AC power of the external power supply 91 into power suitable for charging the main battery 5 will be described. The AC power of the external power supply 91 is input to the low voltage side terminal TL of the charger 40. The coil L removes high frequency components contained in the AC power of the external power source 91. The ACDC conversion circuit 41 converts AC power supplied from the external power supply 91 into DC power. At this time, the step-up / step-down circuit 42 boosts the DC voltage output from the ACDC conversion circuit 41 to a voltage suitable for charging the main battery 5. The DCAC conversion circuit 43 converts the boosted DC power into AC again. This is because power is transmitted in an insulated state by the next transformer Ts. The AC power output from the DCAC conversion circuit 43 is transmitted to the rectification circuit 44 via the transformer Ts. The rectifier circuit 44 has two switching circuits 44a and 44b. In this case (when the power of the external power source is converted to the power for charging), the switching circuits 44a and 44b remain open, the reflux transistor functions, and the AC power on the transformer side is converted to DC to generate a high voltage. Output from the side terminal TH.

  The operation of the charger 40 when converting the output voltage of the main battery 5 to the operating voltage of the auxiliary machine will be outlined. The DC power of the main battery 5 is applied to the high voltage side terminal TH. The controller 4 outputs an appropriate drive command (PWM signal) to the switching circuits 44 a and 44 b of the rectifier circuit 44. The rectifier circuit 44 outputs the DC power of the main battery 5 as AC power to the right side of the transformer Ts in the drawing. The controller 4 should just turn ON / OFF the transistor of the switching circuit 44a and the transistor of the switching circuit 44b alternately. By doing so, an alternating current flows on the right side of the transformer Ts. The AC power is transmitted in an insulated state by the transformer Ts and input to the circuit 43. In this case, the circuit 43 functions as an ACDC conversion circuit that converts AC power input from the right side in the figure into DC and outputs it to the left side. The electric power converted into alternating current is stepped down by the step-up / step-down circuit 42. In the circuit 41, all the switching circuits are maintained OFF, and the DC power output from the step-up / step-down circuit 42 is output as it is to the low voltage side terminal TL. As described above, when the charger 40 steps down the power of the main battery 5 to the operating voltage of the auxiliary machine, the controller 4 connects the low voltage side terminal TL of the charger 40 to the power supply line APL (ie, auxiliary machine group). The switch 32 is controlled so as to be connected to. Note that the circuit configuration shown in FIG. 2 is an example, and the charger 40 provided in the hybrid vehicle 2 is not limited to the circuit shown in FIG.

  Points to be noted regarding the technology of the embodiment will be described. The voltage converter 17 corresponds to an example of a first converter, and the charger 40 corresponds to an example of a second converter. In the embodiment, a hybrid vehicle including an engine and a motor is targeted. However, the technology disclosed in the present specification can also be applied to an electric vehicle including a motor for driving wheels but not including an engine.

  The switching device is not limited to the above-described 1-input 2-output configuration (switching device 32). FIG. 4 shows a block diagram of a hybrid vehicle 2a having a switch 132 having another configuration. FIG. 4 is the same as FIG. 1 except for the switch 132. As shown in FIG. 4, the switch 132 may include a first relay 132a and a second relay 132b. Here, the first relay 132a connects or disconnects the low voltage side terminal TL of the charger 40 to the power supply line APL (that is, the auxiliary machine group). The second relay 132 b connects or disconnects the low voltage side terminal TL of the charger 40 to the external power supply connector 33. The first relay 132a and the second relay 132b are controlled by the controller 4. If the first relay 132a is closed and the second relay 132b is opened, the charger 40 is connected to the auxiliary machine group and is disconnected from the external power supply connector 33. Conversely, if the first relay 132a is opened and the second relay 132b is closed, the charger 40 is disconnected from the auxiliary machinery group and connected to the external power supply connector 33. Further, the external power supply connector 33 corresponds to an open end when an external power supply is not connected. Therefore, the second relay 132b may be closed while the external power supply is not connected.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2, 2a: Hybrid vehicle 4: Controller 5: Main battery 7: System main relay 9: Inverter 12: Motor 13a: Inverter sensor 13b: Motor sensor 14: Power distribution mechanism 16: Engine 17: Voltage converter (first converter)
18: Auxiliary battery 19: Air conditioner (auxiliary)
20: Headlight (auxiliary machine)
21: Car navigation (auxiliary)
31: Sub-relay 32, 132: Switch 33: Connector for external power supply 40: Charger 41: ACDC conversion circuit 42: Buck-boost circuit 43: DCAC conversion circuit 44: Rectifier circuit 90: External power supply plug 91: External power supply

Claims (3)

A wheel drive motor;
A main battery for supplying power to the motor;
An inverter that converts the DC power of the main battery into AC power and outputs it to the motor;
An auxiliary machine that operates at a voltage lower than the output voltage of the main battery;
A first converter for stepping down the voltage of the main battery to the operating voltage of the auxiliary machine and outputting;
A system main relay for connecting or disconnecting the main battery to the inverter and the first converter;
An external power supply connector for connecting the power supply plug of the external power supply,
The high-voltage side terminal is connected to the main battery, and the low-voltage side terminal is connected to the auxiliary machine and the external power supply connector via the switch, and the power applied to the low-voltage side terminal is connected to the main battery. It has the function of converting power for charging and outputting it to the high voltage side terminal, and the function of converting the voltage of the main battery applied to the high voltage side terminal to the operating voltage of the auxiliary machine and outputting it to the low voltage side terminal A second converter;
When an abnormality of the inverter or the motor is detected, the system main relay is opened, the switch is controlled to connect the second converter and the auxiliary machine, and the second converter is output so as to output the operating voltage of the auxiliary machine. A controller to control;
An electric vehicle characterized by comprising:   The switch is a device that selectively switches the connection destination of one input terminal to one of two output terminals, the low voltage side terminal of the second converter is connected to the input terminal, and The electric vehicle according to claim 1, wherein the power connection connector is connected to each of the two output terminals. The electric vehicle according to claim 2, wherein the switching unit switches connection destinations of both a positive electrode and a negative electrode at an input end of the second converter.

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