Controlling equipment and control method of hybrid vehicle

The present invention relates to a control device and a control method for controlling the charge / discharge amount of a battery in order to protect a battery mounted on a hybrid vehicle.

Conventionally, a hybrid vehicle equipped with a motor in addition to an engine has been known as a power source for traveling. Hybrid vehicles include series hybrid vehicles and parallel hybrid vehicles. A series hybrid vehicle is a vehicle in which a motor is driven by using the power generation output of a generator driven by an engine and wheels are driven by the motor. Therefore, since the engine and wheels are not mechanically connected, the engine can be operated at a substantially constant speed in the high fuel consumption and low emission speed range, and the fuel consumption and low emissions are better than those of the conventional engine vehicle. realizable.

On the other hand, in a parallel hybrid vehicle, a motor connected to the engine assists the drive shaft of the engine, and the electric energy obtained by using this motor as a generator is charged to a power storage device to further generate electricity. The electric energy is also used for electrical components in the vehicle. Therefore, since the operating load of the engine can be reduced, better fuel consumption and lower emissions can be realized as compared with the conventional engine vehicle.

In the parallel hybrid vehicle, a motor that assists the output of the engine is directly connected to the output shaft of the engine, and this motor functions as a generator during deceleration or the like to store electricity in a battery or the like (see, for example, Patent Document 1). ), Or a type that can generate driving force by either the engine and the motor, or both, and is equipped with a separate generator. In such a hybrid vehicle, for example, various controls are performed such as assisting the engine output by a motor during acceleration and charging the battery or the like by deceleration regeneration during deceleration, and the electric energy of the battery. It is possible to meet the driver's request by securing (hereinafter referred to as the remaining battery capacity).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 5-49101</text></patcit>

<p> By the way, the battery used in the hybrid vehicle is adapted to supply the insufficient electric power to the electric component when the electric power supplied to the electric component provided in the vehicle exceeds the electric power generated by the motor. Therefore, when the engine is in the idle rotation state, the electric power generated by the motor is likely to exceed the electric power consumed by the electrical components, and there is a problem that the battery is likely to be over-discharged. Further, if the battery of the hybrid vehicle becomes over-discharged, the vehicle must be driven only by the engine, which causes a problem that fuel consumption is deteriorated and power performance is deteriorated.</p><p> The present invention has been made in view of such circumstances, and is a hybrid vehicle that detects an over-discharged state of a battery and controls the charge / discharge amount for battery protection according to the detected over-discharged state. It provides a control device and a control method for the above.</p>

<p> The invention according to claim 1 is an engine that outputs the propulsive force of a vehicle (for example, the engine 1 in the embodiment) and a motor that is directly connected to the engine and generates an auxiliary driving force that assists the output of the engine (for example, the embodiment). The motor 2) in the embodiment and a battery that supplies electric power to the motor and charges the electric energy obtained by operating the motor as a generator when an auxiliary driving force is not required (for example, the battery 3 in the embodiment). And a contactor that interrupts the current supply between the battery and the motor (for example, the main contactor 11 in the embodiment), the electric power generated by the motor, and the electric load supplied by the battery (for example, in the embodiment). An electrical component (not shown), an engine stopping means for stopping the engine under predetermined operating conditions (for example, the engine control device 4 in the embodiment), and a mode determining means for determining whether the engine is in an idling operation state or a stopped state (for example, an engine control device 4). For example, when the mode determination unit 52) in the embodiment and the mode determination means determine that the engine is in a stopped state and the battery is over-discharged, the engine is restarted and the over-discharge further progresses. In the case of a hybrid vehicle, the control device includes a battery protection means (for example, a charge / discharge control unit 54 in the embodiment) for cutting the contactor. With this configuration, if an over-discharge of the battery is detected when the engine is determined to be in a stopped state, the engine is restarted, so that the power generation by the motor can be restarted, and the generated power can be used as the battery. Can be stored in. Further, if the over-discharge further progresses, the contactor is disconnected, so that the discharge from the battery can be completely stopped, and the over-discharge of the battery can be prevented from progressing.</p><p> The invention according to claim 2 is the invention according to claim 1, wherein the battery protection means detects an over-discharge of the battery when the engine is determined to be in an idling operation state by the mode determination means. It is characterized in that the idling speed of the engine is increased, and when the over-discharge further progresses, the power supply to the electric load is stopped. With this configuration, if the over-discharge of the battery is detected when the engine is determined to be in the idling operation state, the idle speed of the engine is increased, so that the amount of power generated by the motor can be increased, which is insufficient. Can supplement the power to be discharged. Further, if the over-discharge further progresses, the power supply to the electric load is stopped, so that the load on the battery can be reduced, and all the power generated by the motor can be used to charge the battery. Over-discharge can be recovered.</p><p> The invention according to claim 3 comprises an engine that outputs the propulsive force of a vehicle (for example, the engine 1 in the embodiment) and a motor that is directly connected to the engine and generates an auxiliary driving force that assists the output of the engine (for example, the embodiment). The motor 2) in the embodiment and a battery that supplies electric power to the motor and charges the electric energy obtained by operating the motor as a generator when an auxiliary driving force is not required (for example, the battery 3 in the embodiment). And a contactor that interrupts the current supply between the battery and the motor (for example, the main contactor 11 in the embodiment), the electric power generated by the motor, and the electric load supplied by the battery (for example, in the embodiment). In a method for controlling a hybrid vehicle that includes electrical components (not shown) and stops the engine under predetermined operating conditions, it is determined whether the engine is in an idling operation state or a stopped state, and when the engine is determined to be in a stopped state, the above-mentioned This is a method for controlling a hybrid vehicle, characterized in that the engine is restarted when an over-discharge of the battery is detected, and the contactor is disconnected when the over-discharge further progresses. With this configuration, if an over-discharge of the battery is detected when the engine is determined to be in a stopped state, the engine is restarted, so that the power generation by the motor can be restarted, and the generated power can be used as the battery. Can be stored in. Further, if the over-discharge further progresses, the contactor is disconnected, so that the discharge from the battery can be completely stopped, and the over-discharge of the battery can be prevented from progressing.</p>

<p> According to the invention of claim 1, if an over-discharge of the battery is detected when the engine is determined to be in a stopped state, the engine is restarted. Therefore, the power generation by the motor is restarted and the generated power is used as the battery. Since the contactor is cut off when the over-discharge further progresses, the discharge from the battery can be completely stopped and the over-discharge of the battery can be prevented from progressing. That is, by stepwise performing "restart of power generation by restarting the engine" and "complete discharge stop by disconnecting all the electric loads connected to the battery" according to the over-discharged state of the battery in the engine stopped state. , Battery over-discharge can be prevented. As a result, it is possible to obtain the effect that deterioration of fuel efficiency and deterioration of power performance can be prevented.</p><p> According to the invention of claim 2, if the over-discharge of the battery is detected when the engine is determined to be in the idling operation state, the idle speed of the engine is increased, so that the amount of power generated by the motor is increased and insufficient. It is possible to supplement the power generated by the battery, and if the over-discharge progresses further, the power supply to the electric load is stopped, so that the load on the battery can be reduced and all the power generated by the motor is used to charge the battery. It can recover the over-discharge of the battery. That is, by stepwise performing "increasing the amount of power generation due to an increase in idle speed" and "cutting off the electric load by stopping the converter for supplying to electrical components" according to the over-discharged state of the battery in the idle operation state. It is possible to prevent over-discharging of the battery.</p><p> According to the invention of claim 3, if an over-discharge of the battery is detected when the engine is determined to be in a stopped state, the engine is restarted. Therefore, the power generation by the motor is restarted and the generated power is used as the battery. Since the contactor is cut off when the over-discharge further progresses, the discharge from the battery can be completely stopped and the over-discharge of the battery can be prevented from progressing. That is, by stepwise performing "restart of power generation by restarting the engine" and "complete discharge stop by disconnecting all the electric loads connected to the battery" according to the over-discharged state of the battery in the engine stopped state. , Battery over-discharge can be prevented. As a result, it is possible to obtain the effect that deterioration of fuel efficiency and deterioration of power performance can be prevented.</p>

Hereinafter, a control device and a control method for a hybrid vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a parallel hybrid vehicle, which is a type of hybrid vehicle according to an embodiment of the present invention. In this figure, reference numeral 1 is an engine operated by the combustion energy of fuel, and reference numeral 2 is a motor used in combination with the engine and operated by electric energy. The driving force of both the engine 1 and the motor 2 is transmitted to the drive wheels (not shown) via a transmission (not shown) consisting of an automatic transmission or a manual transmission. Further, when the hybrid vehicle decelerates, the driving force is transmitted from the driving wheels to the motor 2, and the motor 2 functions as a generator and recovers the kinetic energy of the vehicle body as electric energy.

Reference numeral 3 is a battery that supplies electric power to the motor 2 and charges the electric energy obtained by operating the motor as a generator when no driving force is required. Here, the battery 3 is configured as, for example, a module in which a plurality of cells are connected in series as one unit, and a plurality of modules are further connected in series to form a high-voltage battery. Here, it is assumed that the battery 3 can obtain a voltage of 144 [V] by connecting 120 1.2 [V] batteries in series. A temperature sensor 19 is attached to the module constituting the battery 3.

Reference numeral 4 is an engine control device, which monitors the engine speed, vehicle speed, etc. at predetermined periods, and determines the operation mode such as motor regeneration, assist, and deceleration from these results. At the same time, the engine control device 4 determines the assist / regeneration amount corresponding to the above-mentioned operation mode, and outputs information on the operation mode and the assist / regeneration amount to the motor control device 5. When the motor control device 5 receives the above-mentioned information from the engine control device 4, the motor control device 5 controls the power drive unit 7 or the like that drives / regenerates the motor 2 according to this instruction.

Reference numeral 6 is a battery control device, which calculates the remaining battery capacity of the battery 3. In the following description, the remaining battery capacity is expressed using a percentage as a ratio to the fully charged state of the battery 3. The battery control device 6 also controls the cooling fan 18 installed in the battery box that houses the battery 3 so that the temperature of the battery 3 becomes equal to or lower than a predetermined value in order to protect the battery 3. The engine control device 4, the motor control device 5, and the battery control device 6 are composed of a CPU (central processing unit) and a memory, and realize the functions by executing a program for realizing the functions of the control devices. ..

Reference numeral 7 is a power drive unit, which is composed of two switching elements connected in series and three connected in parallel. The switching element inside the power drive unit 7 is turned on and off by the motor control device 5, whereby the high-voltage DC component supplied from the battery 3 to the power drive unit 7 is supplied to the motor 2 via the three-phase wire. To.

Further, reference numeral 9 is a 12 volt battery for driving various accessories, and this 12 V battery 9 is connected to the battery 3 via the converter 8. The converter 8 steps down the voltage from the battery 3 and supplies it to the 12V battery 9. Reference numeral 10 is a precharge contactor, reference numeral 11 is a main contactor, and the battery 3 and the power drive unit 7 are connected via these contactors. The precharge contactor 10 and the main contactor 11 are turned on and off by the motor control device 5.

Reference numeral 12 is a sensor for detecting the position and rotation speed of the motor 2, and reference numeral 13 is a current sensor for detecting the current flowing in the three-phase line. The detected values of these sensors 12 and 13 are input to the motor control device 5.

Reference numeral 14 is a voltage sensor that detects the voltage of the input unit of the power drive unit 7, and reference numeral 15 is a current sensor that detects the current input to the power drive unit 7. Reference numeral 16 is a voltage sensor that detects the voltage on the battery 3 side. The voltage value and the current value detected by the voltage sensors 14 and 16 and the current sensor 15 are input to the motor control device 5. Reference numeral 17 is a current sensor on the battery 3 side that detects the current flowing on the battery 3 side via the contactor, and the detected current value is input to the battery control device 6.

As described above, each of the sensors 14 to 16 detects the voltage and current on the battery 3 side via the contactors 10 and 11 and the voltage and current on the power drive unit 7 side via the contactor. Further, the current detected by the current sensor 15 is a value obtained by subtracting the current flowing through the converter 8.

Next, the operation of each control device of the hybrid vehicle having the above-described configuration will be briefly described. First, the battery control device 6 calculates the remaining battery capacity based on the values of the input / output current, voltage, temperature, etc. on the battery 3 side, and outputs the values to the motor control device 5. The motor control device 5 outputs the received remaining battery capacity to the engine control device 4. The engine control device 5 determines the operation mode (assist, regeneration, start, deceleration, idle, etc.) and the required power of the motor 2 based on the remaining battery capacity, engine speed, throttle opening, engine torque, actual motor torque, etc. Then, the operation mode and the required power are output to the motor control device 5.

When the motor control device 5 receives the operation mode and the required power from the engine control device 4, the power on the input side of the power drive unit 7 (voltage sensor 14 and current sensor 15 side in FIG. 1) is changed during assist and deceleration. Feedback control is performed so that the required power received from the engine control device 5 is reached. On the other hand, the motor control device 5 performs feedback control so that the power value of the battery 3 (voltage sensor 16 and current sensor 17 side in FIG. 1) becomes the required power during cruise. When the electric power is calculated in this way, the motor control device 5 controls the power drive unit 7 according to the calculated electric power.

Next, when the motor control device 5 receives the actual electric power from the power drive unit 7, it outputs the actual torque converted from the actual electric power to the engine control device 4. The engine control device 4, the motor control device 5, and the battery control device 6 control the engine 1, the motor 2, and the battery 3 by performing the above-described processing at a predetermined timing at any time, and drive the hybrid vehicle.

Next, the control device will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the control device. In FIG. 2, reference numeral 51 is an over-discharge detection unit that detects whether the battery 3 is in an over-discharged state from the voltage and the remaining capacity of the battery 3. Reference numeral 52 is a mode determination unit that determines the current driving mode of the hybrid vehicle based on the mode information output from the engine control device 4. Reference numeral 53a is a determination map in which the measures to be taken against the battery 3 in the over-discharged state of the battery 3 in the idle mode are defined. Reference numeral 53b is a determination map in which the measures to be taken against the battery 3 in the over-discharged state of the battery 3 in the idle stop mode are defined.

Reference numeral 54 is a charge / discharge control unit that takes measures to protect the battery 3 with reference to the determination maps 53a and 53b. Reference numeral 55 is a contactor control unit that controls ON / OFF of the main contactor 11. Reference numeral 56 is a converter control unit that controls the start / stop of the converter 8. Reference numeral 57 is an engine speed setting unit that instructs the engine control device 4 to increase or restart the idle speed of the engine 1. The over-discharge detection unit 51, the mode determination unit 52, the determination maps 53a and 53b, the charge / discharge control unit 54, the contactor control unit 55, the converter control unit 56, and the engine speed setting unit 57 shown in FIG. 2 are shown in FIG. It is provided inside the motor control device 5 shown.

Next, the operation of the control device shown in FIG. 2 will be described with reference to FIGS. 3 to 7. FIG. 3 is a flowchart showing the operation of the mode determination unit 52 shown in FIG. FIG. 4 is a flowchart showing the operation of the over-discharge detection unit 51 shown in FIG. FIG. 5 is a flowchart showing the operation of the charge / discharge control unit 54 shown in FIG. Further, FIGS. 6 and 7 are explanatory views showing the configurations of the determination maps 53a and 53b shown in FIG.

First, the determination maps 53a and 53b will be described with reference to FIGS. 6 and 7. FIG. 6 is a determination map 53b referenced when the operation mode is the idle stop mode, and the operation according to the remaining battery capacity or the battery voltage is defined. In this example, engine 1 is defined to restart when the remaining battery capacity is 20% or the battery voltage drops below 120V. It is also defined to turn off the main contactor 11 when the remaining battery capacity is 10% or the battery voltage drops below 108V.

Further, FIG. 7 is a determination map 53a referred to when the operation mode is the idle mode, and the operation according to the remaining battery capacity or the battery voltage is defined as in the determination map 53b. In this example, the idle speed of engine 1 is defined to increase when the remaining battery capacity is 20% or the battery voltage drops below 120V. It is also defined to shut down converter 8 when the remaining battery capacity is 10% or the battery voltage drops below 108V.

Subsequently, the operation of the mode determination unit 52 for mode determination will be described with reference to FIG. First, the mode determination unit 52 reads the mode information output from the engine control device 4 (step S1). The driving modes of the hybrid vehicle include modes such as assist, regeneration, start, deceleration, idle, and idle stop. The idle mode is a mode when the engine 1 is in idle rotation, and the idle stop mode is a mode in which the fuel supplied to the engine 1 is cut when a predetermined condition is satisfied in the idle mode. It is a mode to stop. The engine control device 4 selects one of these operation modes according to the driving situation of the vehicle, and notifies the motor control device 5 of the selected operation mode. In response to this, the motor control device 5 controls the motor 2 according to its operation mode. Here, the mode information read is the same as the information notified from the engine control device 4 for controlling the motor 2.

Next, the mode determination unit 52 determines what the read mode is (step S2). As a result of this determination, if it is in the idle mode or the idle stop mode, the process proceeds to step S3, and if it is an operation mode other than these, the process returns to step S1.

If the result of the determination in step S2 is idle mode or idle stop mode, the result is notified to the over-discharge detection unit 51 and the charge / discharge control unit 54 (step S3). The content to be notified at this time is notified so that it can be determined whether the mode is the idle mode or the idle stop mode.

In this way, the mode determination unit 52 is the over-discharge detection unit 51 only when the rotation speed of the engine 1 is equal to or less than the idle speed and the amount of power generated by the motor 2 is small in either the idle mode or the idle stop mode. And the charge / discharge control unit 54 is notified of the current operation mode. The mode determination unit 52 repeatedly executes the operation shown in FIG.

Next, the operation of the over-discharge detection unit 51 to detect the over-discharge state of the battery 3 will be described with reference to FIG. First, the over-discharge detection unit 51 reads the current operation mode output from the mode determination unit 52 (step S11). The operation mode read here is an idle mode or an idle stop mode because the output of the mode determination unit 52 is read.

Next, the over-discharge detection unit 51 determines what the read operation mode is (step S12). As a result of this determination, if it is in idle mode, the map used for determination is switched to the determination map 53a corresponding to the idle mode (step S13). On the other hand, in the idle stop mode, the map used for the judgment is switched to the judgment map 53b corresponding to the idle stop mode (step S14).

Next, the over-discharge detection unit 51 reads the voltage of the battery 3 and the remaining battery capacity notified from the battery control device 6 (step S15). The output of the voltage sensor 16 is used as the voltage of the battery 3.

Next, the over-discharge detection unit 51 detects the over-discharge state of the battery 3 from the determination map 53a or 53b currently switched to either of them and the read battery voltage and remaining battery capacity (step S16). ). To determine the over-discharge of the battery 3, either the remaining battery capacity notified from the battery controller 6 or the voltage value detected by the voltage sensor 16 is a predetermined value (for example, the remaining battery capacity is 20% and the battery voltage is 20%). When it falls below 120V), it is judged to be in an over-discharged state.

As a result of detection in step S16, it is determined whether or not the battery 3 is in an over-discharged state (step S17). As a result of this determination, if it is not over-discharged, the process returns to step S11 and the above-described process is repeated.

As a result of the determination in step S17, when the battery 3 is in the over-discharged state, the over-discharge detection unit 51 notifies the charge / discharge control unit 54 of the over-discharged state of the battery 3 (step S18). The content notified here is the current remaining battery capacity, which is a value of 20 to 0%. Further, even when the detection of over-discharge is detected by the battery voltage, it is replaced with the remaining battery capacity corresponding to this battery voltage and notified.

In this way, the over-discharge detection unit 51 determines whether the determination map 53a referred to in the idle mode and the determination map 53b referred to in the idle stop mode are in the idle mode or the idle stop mode at the present time. It switches accordingly, detects the over-discharged state of the battery 3 according to this determination map, and notifies the charge / discharge control unit 54 of the detected state. The over-discharge detection unit 51 repeatedly executes the operation shown in FIG.

Next, the operation in which the charge / discharge control unit 54 protects the battery 3 will be described with reference to FIG. First, the charge / discharge control unit 54 reads the overdischarge state output from the overdischarge detection unit 51 (step S21). Subsequently, the charge / discharge control unit 54 determines whether or not the read content is a notification indicating that the overdischarge state is present (step S22). As a result of this determination, if the content does not notify the over-discharged state, the charge / discharge control unit 54 returns to step S21 and waits until there is a notification indicating the over-discharged state.

Next, when the content notified from the over-discharge detection unit 51 indicates the over-discharge state, the charge / discharge control unit 54 reads the current mode output from the mode determination unit 52. Subsequently, the charge / discharge control unit 54 switches the determination map 53a or the determination map 53b according to the read operation mode (steps S24, S25, S26).

Next, the charge / discharge control unit 54 refers to the determination map 53a or 53b switched in step S25 or S26, and takes measures for battery protection according to the overdischarge state (step S27). The measures to be taken for battery 3 differ depending on the current operation mode. In the idle stop mode, when the remaining battery capacity is 20% or less, the power generation by the motor 2 is restarted by restarting the engine 1. This is done by the charge / discharge control unit 54 instructing the engine speed setting unit 57 to restart the engine. In response to this instruction, the engine speed setting unit 57 sets the idle speed and notifies the engine control device 4 of the engine restart. As a result, the power generated by the motor 2 is restarted, so that the power generated here can be stored in the battery 3.

However, engine 1 cannot be restarted unless the transmission is neutral and conditions such as the clutch being disengaged that ensure safety when restarting the engine are met, so the clutch remains engaged by the driver. If this is the case, engine 1 cannot be restarted. Therefore, if the engine 1 cannot be restarted even though the engine restart is instructed and the remaining battery capacity becomes 10% or less, the main contactor 11 is turned off to discharge the battery 3. Stop completely. This is done by the charge / discharge control unit 54 instructing the contactor control unit 55 to turn off the main contactor 11. In response to this instruction, the contactor control unit 55 outputs a signal for turning off the main contactor 11, which turns off the main contactor 11. As a result, the discharge from the battery 3 is completely stopped, so that further over-discharge of the battery 3 can be prevented.

In this way, as the remaining battery capacity in the idle stop mode decreases, "restart of power generation by restarting the engine" and "complete discharge stop by disconnecting all the electrical loads connected to the battery" are performed step by step. Thereby, over-discharging of the battery 3 can be prevented. When the remaining battery capacity is recovered, "contactor ON" and "idle stop" are performed in stages.

On the other hand, in the idle mode, when the remaining battery capacity is 20% or less, the motor power generation amount is increased by increasing the idle speed. This is done by the charge / discharge control unit 54 instructing the engine speed setting unit 57 to increase the idle speed. In response to this instruction, the engine speed setting unit 57 sets the idle speed and notifies the engine control device 4 of the idle speed. This makes up for the lack of power.

When the remaining battery capacity further decreases to 10% or less, the electric load of the battery 3 is cut off by further stopping the converter 8 in addition to increasing the idle speed. This is done by the charge / discharge control unit 54 instructing the converter control unit 56 to stop the converter 8. In response to this instruction, the converter control unit 56 outputs a signal to the converter 8 to stop, whereby the converter 8 is stopped. While the converter 8 is stopped, the power supply to the electrical components is stopped, during which the required power is supplied from the 12V battery 9. As a result, the load on the battery 3 can be reduced. However, since the main contactor 11 is in the ON state, the electric power generated by the motor 2 when the engine 1 is idle can be stored in the battery 3.

In this way, as the remaining battery capacity in the idle mode decreases, "increasing the amount of power generation due to an increase in idle speed" and "cutting off the electric load by stopping the converter to supply electrical components" are performed step by step. , Battery 3 can be prevented from over-discharging. When the remaining battery capacity is recovered, "converter start" and "idle rotation speed initialization" are performed step by step. The charge / discharge control unit 54 repeatedly executes the operation shown in FIG.

<figref num="1">It is a block diagram which shows the structure of the control device of a hybrid vehicle.</figref><figref num="2">It is a block diagram which shows the structure of a control device.</figref><figref num="3">It is a flowchart which shows the operation of the mode discriminating part 52 shown in FIG.</figref><figref num="4">It is a flowchart which shows the operation of the over-discharge detection part 51 shown in FIG.</figref><figref num="5">It is a flowchart which shows the operation of the charge / discharge control unit 54 shown in FIG.</figref><figref num="6">It is explanatory drawing which shows the structure of the determination map 53a shown in FIG.</figref><figref num="7">It is explanatory drawing which shows the structure of the determination map 53b shown in FIG.</figref>

Code description

1 ... engine, 2 ... motor, 3 ... battery, 4 ... engine control device, 5 ... motor control device, 8 ... converter, 11 ... main contactor, 51 ... Over-discharge detection unit, 52 mode discrimination unit, 53a, 53b judgment map, 54 charge / discharge control unit, 55 contactor control unit, 56 converter control unit, 57 Engine speed setting unit.