Electric vehicles

Abstract

To achieve distribution of regenerative electric power automatically.SOLUTION: An electric vehicle 1 comprises: a battery circuit 100 which includes a battery 11, a transistor 51 which supplies regenerative electric power to the battery 11 when voltage is applied to a gate, and a converter 61 which applies the voltage to the gate of the transistor 51 when charging upper limit voltage of the battery 11 is larger than present voltage of the battery 11; and a BR circuit 200 which includes a brake resistor 21 and PTO (Power Take OFF) 22, a transistor 53 which supplies the regenerative electric power to at least one of the brake resistor and the PTO when voltage is applied to a gate, and a converter 62 which applies the voltage to the gate of the transistor 53 when the charging upper limit voltage of the battery 11 is smaller than the present voltage of the battery 11.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] One aspect of the present invention relates to an electric vehicle.

Background Art

[0002] Patent Document 1 discloses an electric vehicle including a switching switch that selectively sends regenerative power generated during regenerative braking operation to a battery and a capacitor, and a switching switch that sends power stored in the capacitor to the battery or an external energy recovery device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when regenerative power is supplied to the battery when the voltage of the battery is higher than the chargeable voltage, the battery may be damaged due to overcharging. Therefore, it is important to appropriately distribute the regenerative power. Conventionally, such distribution of regenerative power has been carried out by control. However, considering the burden on the driver and the like, it is preferable that such distribution of regenerative power is automatically carried out.

[0005] One aspect of the present invention has been made in view of the above circumstances, and an object thereof is to automatically perform the distribution of regenerative power.

Means for Solving the Problems

[0006] An electric vehicle according to one aspect of the present invention comprises: a battery; a first circuit having a battery; a first transistor that supplies regenerative power to the battery when a voltage is applied to its gate; and a first comparator that applies a voltage to the gate of the first transistor when the battery's charging limit voltage is greater than the battery's current voltage; and a second circuit having at least one of a brake resistor and a PTO (Power Take Off); a second transistor that supplies regenerative power to at least one of the brake resistor and the PTO when a voltage is applied to its gate; and a second comparator that applies a voltage to the gate of the second transistor when the battery's charging limit voltage is less than the battery's current voltage.

[0007] In an electric vehicle according to one aspect of the present invention, if the battery's charging limit voltage is greater than the battery's current voltage, a voltage is applied to the gate of the first transistor, and regenerative power is supplied to the battery. If the battery's charging limit voltage is less than the battery's current voltage, a voltage is applied to the gate of the second transistor, and regenerative power is supplied to at least one of the brake resistor and the PTO. In this way, the comparator (semiconductor) compares the battery's current voltage with the battery's charging limit voltage, and if overcharging does not occur, a voltage is applied to the gate of the transistor that supplies regenerative power to the battery. If overcharging occurs, a voltage is applied to the gate of the transistor that supplies regenerative power to the brake resistor, etc. This allows for the appropriate distribution of regenerative power automatically by the circuit configuration including transistors, without the need for control by an ECU or the like.

[0008] The second circuit includes both a brake resistor and a PTO, and may further include a variable resistor between the second transistor and at least one of the brake resistor and the PTO. By providing such a variable resistor, the regenerative power can be distributed to the brake resistor and the PTO in a desired ratio by adjusting the resistance value of the variable resistor. In other words, the regenerative power can be appropriately distributed to a wider range of components.

[0009] The second circuit further includes a cooling device and a third transistor that supplies regenerative power to the cooling device when a voltage is applied to its gate. The second comparator may apply a voltage to the gates of the second transistor and the third transistor when the battery's upper charge limit voltage is lower than the current battery voltage. In this way, the voltage from the second comparator is applied not only to the gate of the second transistor but also to the gate of the third transistor that supplies regenerative power to the cooling device (i.e., the gate voltage is shared), which allows the cooling device's heat dissipation capacity to be linked to a brake resistor or the like. [Effects of the Invention]

[0010] According to one aspect of the present invention, the distribution of regenerative power can be performed automatically. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the basic configuration of an electric vehicle according to this embodiment. [Figure 2] This is a diagram showing an example of a circuit diagram. [Modes for carrying out the invention]

[0012] Various embodiments will be described in detail below with reference to the drawings. Note that the same or corresponding parts will be denoted by the same reference numerals in each drawing, and redundant descriptions of the same or corresponding parts will be omitted.

[0013] The vehicle according to this embodiment is an electric vehicle equipped with a motor that outputs driving force for propulsion. Figure 1 is a diagram showing the basic configuration of the electric vehicle 1 according to this embodiment. Note that in Figure 1, some of the basic configuration of the electric vehicle 1 (drive wheels, differential device, gear mechanism, etc.) is omitted. The electric vehicle 1 is, for example, a commercial vehicle for transporting goods.

[0014] As shown in Figure 1, the electric vehicle 1 comprises a battery 11, a drive motor inverter 12, a drive motor 13, a fuel cell 14, and an ECU 15.

[0015] The battery 11 is a drive energy source that supplies power to drive the drive motor 13. The battery 11 may also notify the ECU 15 of its status, including temperature and output limit values.

[0016] The drive motor inverter 12 is, for example, a three-phase bridge circuit having IGBTs and diodes, and switches the on / off state of the IGBTs in response to a control signal from the ECU 15 to perform power control or regenerative control.

[0017] The drive motor 13 outputs driving force for propulsion. The drive motor 13 is, for example, an AC synchronous type and functions as both an electric motor and a generator. The drive motor 13 has a rotor made of permanent magnets and a stator around which three-phase windings are wound. Drive wheels (not shown) are connected to the rotor via a gear mechanism (not shown) and a differential device (not shown).

[0018] The fuel cell 14 supplies power to drive the drive motor 13 in accordance with the control signal from the ECU 15. The electric vehicle 1 does not necessarily have to be equipped with a fuel cell 14. The electric vehicle 1 may also include an engine and a generator as a power supply unit that supplies power to drive the drive motor 13.

[0019] The ECU15 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), backup RAM, an input / output interface, and a communication interface. The ECU15 is a control unit that controls each of these components.

[0020] In the electric vehicle 1, regenerative power from the drive motor 13 can be supplied to the battery 11 via the drive motor inverter 12. Here, if the regenerative power is supplied to the battery 11 when the voltage of the battery 11 is higher than the chargeable voltage, the battery 11 may be damaged due to overcharging. Therefore, in the electric vehicle 1 according to this embodiment, the distribution destination of the regenerative power is changed according to the voltage situation of the battery 11. Specifically, in the electric vehicle 1, when the charge upper limit voltage of the battery 11 is higher than the voltage of the battery 11, the regenerative power is supplied to the battery 11. On the other hand, when the charge upper limit voltage of the battery 11 is lower than the voltage of the battery 11, the regenerative power is supplied to a configuration other than the battery 11 (such as a brake resistor). The electric vehicle 1 realizes such distribution of regenerative power by a circuit configuration including transistors without depending on the control of the ECU 15 or the like. Hereinafter, the circuit configuration of the electric vehicle 1 will be described with reference to FIG. 2.

[0021] FIG. 2 is a diagram showing an example of a circuit diagram of the electric vehicle 1 (a circuit diagram of a configuration related to the distribution of regenerative power). As shown in FIG. 2, the electric vehicle 1 according to this embodiment includes, as a circuit related to the distribution of regenerative power, a battery circuit 100 (first circuit) including the battery la and a BR circuit 200 (second circuit) including a brake resistor 21 and a PTO (Power Take Off) 22.

[0022] The battery circuit 100 has the battery 11, a transistor 51 (first transistor), a thermostat 19, a transistor 52, and a comparator 61 (first comparator).

[0023] Comparator 61 is composed of an operational amplifier. Comparator 61 compares two input voltages and switches the output. When the voltage at the non-inverting input terminal (+ terminal) is higher, the output voltage is Hi; when the voltage at the inverting input terminal (- terminal) is higher, the output voltage is Lo. Now, in Comparator 61, the + terminal is set to the ground voltage, and the - terminal is set to the voltage of the battery voltage V - voltage offset V0. Here, the battery voltage V is the current voltage of battery 11. Also, the voltage offset V0 is the charging upper limit voltage of battery 11. When the voltage at the + terminal (ground voltage) is higher than the voltage at the - terminal (battery voltage V - voltage offset V0), that is, when the battery voltage V < voltage offset V0 (the charging upper limit voltage of battery 11) holds, the output voltage is set to Hi, and a voltage is applied to the gates of transistors 51 and 52.

[0024] Transistor 51 supplies regenerative power to battery 11 when a voltage is applied to its gate. The gate of transistor 51 is connected to the output terminal of comparator 61. When a voltage is applied from comparator 61 to the gate of transistor 51, regenerative power is supplied from the drain to the source of transistor 51. In this case, regenerative power is supplied to battery 11 connected to the source of transistor 51. The state of charge (SOC) of battery 11 when regenerative power is supplied is, for example, 5% - 95%.

[0025] Transistor 52 is provided in parallel with transistor 51. Transistor 52 supplies regenerative power to the thermostat 19 when a voltage is applied to its gate. The gate of transistor 52 is connected to the output terminal of comparator 61. When a voltage is applied from comparator 61 to the gate of transistor 52, regenerative power is supplied from the drain to the source of transistor 52. In this case, regenerative power is supplied to the thermostat 19 connected to the source of transistor 52. The state of charge (SOC) of battery 11 when regenerative power is supplied is, for example, 5% - 95%.

[0026] The BR circuit 200 includes a brake resistor 21, a PTO 22, a variable resistor 70, a transistor 53 (second transistor), a cooling device 23, a transistor 54 (third transistor), and a comparator 62 (second comparator).

[0027] Comparator 62 is composed of an operational amplifier. Comparator 62 compares two input voltages and switches its output. Comparator 62 sets the output voltage to Hi if the voltage at the non-inverting input terminal (+ terminal) is greater, and the output voltage to Lo if the voltage at the inverting input terminal (- terminal) is greater. Currently, in comparator 62, the + terminal is the voltage of battery voltage V - voltage offset V0, and the - terminal is the ground voltage. Comparator 61 sets the output voltage to Hi and applies voltage to the gates of transistors 53 and 54 when the voltage at the + terminal (battery voltage V - voltage offset V0) is greater than the voltage at the - terminal (ground voltage), that is, when voltage offset V0 (maximum charging voltage of battery 11) < battery voltage V.

[0028] The brake resistor 21 is provided in parallel with the PTO 22. The variable resistor 70 is provided between the transistor 53 and the brake resistor 21. With this configuration, the distribution ratio of regenerative power to the brake resistor 21 and the PTO 22 can be adjusted by adjusting the resistance value of the variable resistor 70.

[0029] Transistor 53 supplies regenerative power to the brake register 21 and PTO 22 when a voltage is applied to its gate. The distribution ratio of regenerative power in the brake register 21 and PTO 22 is adjusted by the resistance value of the variable resistor 70, as described above. The gate of transistor 53 is connected to the output terminal of comparator 62. When a voltage is applied to the gate of transistor 53 from comparator 62, regenerative power is supplied from the drain to the source of transistor 53. In this case, regenerative power is supplied to the brake register 21 and PTO 22, which are connected to the source of transistor 53. The state of charge (SOC) of the battery 11 when regenerative power is supplied is, for example, 95% to 100%.

[0030] Transistor 54 is connected in parallel with transistor 53. Transistor 54 supplies regenerative power to the cooling device 23 when a voltage is applied to its gate. The gate of transistor 54 is connected to the output terminal of comparator 62. When a voltage is applied to the gate of transistor 54 from comparator 62, regenerative power is supplied from the drain to the source of transistor 54. In this case, regenerative power is supplied to the cooling device 23, which is connected to the source of transistor 54. The State of Charge (SOC) of the battery 11 when regenerative power is supplied is, for example, 95% to 100%.

[0031] Next, the effects and advantages of the electric vehicle 1 according to this embodiment will be described.

[0032] The electric vehicle 1 according to this embodiment includes a battery circuit 100 having a battery 11, a transistor 51 that supplies regenerative power to the battery 11 when a voltage is applied to its gate, and a comparator 61 that applies a voltage to the gate of the transistor 51 when the upper limit charging voltage of the battery 11 is greater than the current voltage of the battery 11; and a BR circuit 200 having a brake resistor 21 and a PTO (Power Take Off) 22, a transistor 53 that supplies regenerative power to at least one of the brake resistor and the PTO when a voltage is applied to its gate, and a comparator 62 that applies a voltage to the gate of the transistor 53 when the upper limit charging voltage of the battery 11 is less than the current voltage of the battery 11.

[0033] In the electric vehicle 1 according to this embodiment, if the battery 11's charging limit voltage is greater than the battery 11's current voltage, a voltage is applied to the gate of transistor 51, and regenerative power is supplied to the battery 11. Also, if the battery 11's charging limit voltage is less than the battery 11's current voltage, a voltage is applied to the gate of transistor 53, and regenerative power is supplied to at least one of the brake resistor 21 and the PTO 22. In this way, the comparators 61 and 62 (semiconductors) compare the battery 11's current voltage with the battery 11's charging limit voltage, and if overcharging does not occur, a voltage is applied to the gate of transistor 51 which supplies regenerative power to the battery 11. If overcharging occurs, a voltage is applied to the gate of transistor 53 which supplies regenerative power to the brake resistor 21, etc., thereby enabling the regenerative power to be appropriately distributed automatically by the circuit configuration including transistors, without the need for control by an ECU or the like.

[0034] The BR circuit 200 may further include a variable resistor 70 between the transistor 53 and the brake resistor 21. By providing the variable resistor 70 in this way, the regenerative power can be distributed to the brake resistor 21 and the PTO 22 in a desired ratio by adjusting the resistance value of the variable resistor 70. In other words, the regenerative power can be appropriately distributed to a wider range of components.

[0035] The BR circuit 200 further includes a cooling device 23 and a transistor 54 that supplies regenerative power to the cooling device 23 when a voltage is applied to its gate. The comparator 62 may apply a voltage to the gates of transistor 53 and transistor 54 when the upper limit charging voltage of the battery 11 is lower than the current voltage of the battery 11. In this way, the voltage from the comparator 62 is applied not only to the gate of transistor 53 but also to the gate of transistor 54 that supplies regenerative power to the cooling device 23 (i.e., the gate voltage is shared), which allows the heat removal capacity of the cooling device 23 to be linked to the brake resistor 21, etc.

[0036] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, although the battery circuit 100 has been described as having a battery 11 and a temperature controller 19 as recipients of regenerative power, it is not limited to this, and may consist of only a battery 11. Also, although the variable resistor 70 in the BR circuit 200 has been described as being provided between the transistor 53 and the brake resistor 21, it is not limited to this, and the variable resistor 70 may be provided between the transistor 53 and the PTO 22. Furthermore, although the BR circuit 200 has been described as having a brake resistor 21, a PTO 22, and a cooling device 23 as recipients of regenerative power, it is not limited to this, and may consist of only one of these configurations. [Explanation of Symbols]

[0037] 1...Electric vehicle, 11...Battery, 21...Brake resistor, 22...PTO, 23...Cooling system, 51...Transistor (1st transistor), 53...Transistor (2nd transistor), 54...Transistor (3rd transistor), 61...Comparator (1st comparator), 62...Comparator (2nd comparator), 70...Variable resistor, 100...Battery circuit (1st circuit), 200...BR circuit (2nd circuit).

Claims

1. A first circuit comprising a battery, a first transistor that supplies regenerative power to the battery when a voltage is applied to its gate, and a first comparator that applies a voltage to the gate of the first transistor when the battery's charging limit voltage is greater than the battery's current voltage, The second circuit comprises at least one of a brake resistor and a PTO, a second transistor that supplies regenerative power to at least one of the brake resistor and the PTO when a voltage is applied to its gate, and a second comparator that applies a voltage to the gate of the second transistor when the battery's upper charge limit voltage is lower than the battery's current voltage. The second circuit is, Having both the brake register and the PTO, An electric vehicle further comprising a variable resistor between the second transistor and at least one of the brake resistor and the PTO.

2. The second circuit is, The device further comprises a cooling device and a third transistor that supplies regenerative power to the cooling device when a voltage is applied to its gate. The second comparator is, The electric vehicle according to claim 1, wherein a voltage is applied to the gates of the second transistor and the third transistor when the upper limit charging voltage of the battery is lower than the current voltage of the battery.

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