JP5318238B2 - Power management apparatus, power management method, and power management system - Google Patents

Description

  The present invention relates to a power management device, a power management method, and a power management system, and in particular, a power management device, a power management method, and a power source that are used by being mounted on a vehicle including a plurality of capacitors and a power converter. It relates to the management system.

  Against the backdrop of the global greenhouse gas problem, there is a need for the development of technology to reduce fuel consumption in automobiles. Under such circumstances, a technique has been developed that reduces the fuel consumption of a vehicle by collecting kinetic energy generated during deceleration as electric power and reducing the amount of power generation other than during deceleration. In such a vehicle, when the voltage of the generator is increased, the generated power can be stored more efficiently. Therefore, if power is generated and stored at a voltage higher than the voltage range for operating the engine's auxiliary equipment, and the power reduced by the power converter is supplied to the auxiliary equipment and the battery, the power can be used efficiently. it can. However, in such a system, if the power converter breaks down, it becomes impossible to supply power from the high voltage circuit to the low voltage circuit, so that power is supplied only to the auxiliary equipment from the battery. Thus, when the battery charge amount decreases, the auxiliary machines do not operate, and in the worst case, there is a problem that the vehicle cannot travel.

  As a conventional vehicle power management device, a system including two power converters has been proposed in preparation for failure of a power converter (see, for example, Patent Document 1).

  In addition, when a short-circuit failure occurs between the high-voltage circuit and the low-voltage circuit, the system supplies power to the low-voltage circuit by reducing the power generation amount of the generator so that the voltage is the same as that of the low-voltage circuit. Has been proposed (see, for example, Patent Document 2).

JP-A-11-122701 (5th page, FIG. 1) Japanese Patent No. 4143267 (5th page, FIG. 1)

  Since the conventional power management device described in Patent Document 1 has a configuration in which two power converters are connected in parallel in preparation for a failure of the power converter, a significant cost increase due to the dual system has occurred. In addition, there are problems such as an increase in size.

  In addition, another conventional power management device described in Patent Document 2 generates power from a generator so that the voltage is the same as that of the low voltage circuit when a short circuit fault occurs between the high voltage circuit and the low voltage circuit. The amount is controlled so that power is supplied to the low voltage circuit. However, in the case of a normal failure in which the power converter does not short-circuit the high-voltage circuit and the low-voltage circuit, problems such as failure to supply power to the low-voltage circuit remain.

  The present invention has been made to solve such a problem, and even when a power converter failure occurs, power can be supplied from the high voltage circuit to the low voltage circuit, and the auxiliary equipment of the vehicle is stopped. It is an object of the present invention to obtain a power management device, a power management method, and a power management system that can stably continue traveling of a vehicle.

  The present invention provides a first circuit including a first capacitor, a second circuit including a second capacitor, and converting the electric power of the first capacitor into the second capacitor and a vehicle auxiliary device. A power management device provided in a vehicle including a power converter to be supplied and a generator connected to the first capacitor and generating power by external torque to charge the first capacitor, 1 is connected between the first circuit and the second circuit, and is normally in a non-conductive state between the first circuit and the second circuit. A first switch that switches from a state to a conductive state; and when a failure of the power converter is detected, the generator generates electric power within the generator from a normal power generation operation that charges the first capacitor to the generator. Command to switch to a voltage drop operation that consumes the After the operation, when the difference between the voltage of the first capacitor and the voltage of the second capacitor falls within a first predetermined voltage range, the switching command is output to the first switch. And a power management unit.

  The present invention provides a first circuit including a first capacitor, a second circuit including a second capacitor, and converting the electric power of the first capacitor into the second capacitor and a vehicle auxiliary device. A power management device provided in a vehicle including a power converter to be supplied and a generator connected to the first capacitor and generating power by external torque to charge the first capacitor, 1 is connected between the first circuit and the second circuit, and is normally in a non-conductive state between the first circuit and the second circuit. A first switch that switches from a state to a conductive state; and when a failure of the power converter is detected, the generator generates electric power within the generator from a normal power generation operation that charges the first capacitor to the generator. Command to switch to a voltage drop operation that consumes the After the operation, when the difference between the voltage of the first capacitor and the voltage of the second capacitor falls within a first predetermined voltage range, the switching command is output to the first switch. The power management device includes a power management unit that can supply power from the high-voltage circuit to the low-voltage circuit even when a power converter failure occurs. The vehicle can be stably driven without stopping the machinery.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which showed the structure of the power management apparatus which concerns on Embodiment 1 of this invention, and its periphery. It is explanatory drawing which showed the relationship between the engine speed in Embodiment 1 of this invention, and the voltage between the terminals of a generator with the graph. It is a time chart which shows the operation | movement of the power management apparatus which concerns on Embodiment 1 of this invention, and its periphery. It is a flowchart which shows the flow of a process of the power supply management apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the flow of a process of the power supply management apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which showed the structure of the power supply management apparatus which concerns on Embodiment 2 of this invention, and its periphery. It is a time chart which shows the operation | movement of the power management apparatus which concerns on Embodiment 2 of this invention, and its periphery. It is a flowchart which shows the flow of a process of the power management apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the flow of a process of the power management apparatus which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
A power management apparatus and a power management method according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 1 is a configuration diagram showing a configuration of a power management device and its periphery according to Embodiment 1 of the present invention. The configuration shown in FIG. 1 is all provided in the vehicle. In FIG. 1, 1 is a 1st electrical storage device, 2 is a 2nd electrical storage device. The first and second capacitors 1 and 2 can be charged and discharged with electric devices connected to each of them. The first battery 1 is a high-voltage battery, and the second battery 2 is a low-voltage battery. The first battery 1 is charged by a generator 3 (to be described later) to store electric power, and converted into electric power through a power converter 4 (to be described later). The second battery 2 (low voltage system) and the vehicle accessories 5 (to be described later). To supply power.

  The vehicle travels using an engine (not shown) as a driving force, and the output of the engine is controlled by the engine control device 14. The engine control unit 14 includes an accelerator opening degree detecting means 15 for detecting the opening degree of an accelerator pedal operated as a driver's acceleration request, an engine speed detecting means 11 for detecting the engine speed, and a throttle. A signal from the throttle opening detecting means 12 for detecting the opening can be input, and a necessary engine output is calculated based on the information and a required torque from each system, and the injector 13 Is commanded to inject fuel.

  In FIG. 1, reference numeral 3 denotes a generator, which is connected to the first battery 1, is supplied with torque from the engine, generates power, and charges the first battery 1. The generator 3 includes a field winding 3c, an armature winding 3b, a field current control circuit 3d for controlling a current flowing in the field winding 3c, and an AC power generated by the armature winding 3b. Is provided with a rectifier circuit 3a for converting the current into a direct current. The field current control circuit 3d can control the current flowing through the field winding 3c by changing the voltage applied to both ends of the field winding 3c according to the PWM waveform by switching of the semiconductor element. In order to increase the rectification efficiency, the rectifier circuit 3a includes a semiconductor element that can be turned on / off in parallel with a generally used diode. The semiconductor element is turned on / off according to the phase of the generated AC power. Rectified. Further, the generator 3 includes a thermistor 3e as a temperature sensor inside, and can measure the temperature of the generator 3.

  In FIG. 1, reference numeral 5 denotes auxiliary equipment for the vehicle, which represents electrical equipment of the vehicle including control units such as a headlight, an air conditioner, an audio, an engine, and a power window. Reference numeral 4 denotes a power converter, which converts power generated by the generator 3 and stored in the first capacitor 1 into a voltage lower than that of the first capacitor 1 to compensate for the second capacitor 2 and the vehicle. Supply to machinery 5. Reference numeral 6 denotes a first switch, which is a high voltage circuit (first circuit) including the generator 3 and the first capacitor 1, a low voltage circuit (first circuit) including the second capacitor 2 and the vehicle accessories 5. In the normal state, the high-voltage circuit and the low-voltage circuit are non-conductive, and it is determined that the power management unit 7 described later satisfies a predetermined condition, and a switching command is issued. When output, the switch receives the switching command and switches between the high voltage circuit and the low voltage circuit from the non-conductive state to the conductive state. A power management unit 7 outputs a command for instructing power generation and a command for prohibiting power generation to the power generator 3 and commands torque during power generation. In addition, the power management unit 7 switches the operation of the first switch 6 to the non-conducting state at the normal time and switches from the non-conducting state to the conducting state when a failure of the power converter 4 is detected. Is output. Further, the power supply management unit 7 internally detects the voltage between the terminals of the first battery 1 and the voltage between the terminals of the second battery 2 for detecting the voltage between the terminals of the first battery 1. The terminal voltage detection means 7b of the second capacitor is provided, and the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 can be measured. Furthermore, the power management unit 7 receives a detection signal from the power converter output current detection means 10 connected between the power converter 4 and the second battery 2, and thereby the output of the power converter 4. Current can be measured. The power management unit 7 detects a failure of the power converter 4 based on a change in the value of the output current of the power converter 4. The power management unit 7 and the engine control device 14 have a communication function, and can share information used for the control.

  The power management apparatus according to the first embodiment of the present invention includes a power management unit 7 and a first switch 6. In addition, the power management system according to Embodiment 1 of the present invention includes a first battery 1, a second battery 2, a power converter 4, a generator 3, a first switch 6, and a power management unit 7. ing. The power converter output current detection means 10 may also be a component of the power management device. Furthermore, the present invention is also a power management method implemented by the power management apparatus or power management system.

  Hereinafter, the operation of the generator 3 according to Embodiment 1 of the present invention will be described with reference to FIG.

  The operation state of the generator 3 according to the first embodiment of the present invention is as follows: normal power generation operation, power generation prohibition operation prohibiting normal power generation (however, a low-efficiency power generation operation and armature winding energization operation described later are not performed) ), Low efficiency power generation operation executed during power generation prohibition operation and armature winding energization operation. Among these, the normal power generation operation and the power generation prohibition operation (however, when the low efficiency power generation operation and the armature winding energization operation described later are not performed) are performed when the generator 3 is set in the normal operation mode, The low-efficiency power generation operation and the armature winding energization operation are performed when the generator 3 is set in the voltage reduction operation mode. A general generator generates an electromotive force by changing a magnetic flux interlinked with an armature winding. Assuming that the number of windings is the same, the greater the interlinkage magnetic flux is, the faster the magnetic flux changes, the greater the electromotive force. The interlinkage magnetic flux includes a magnetic material and a magnetic flux generated by energizing the field winding. The generator 3 according to the first embodiment of the present invention includes a field winding 3c. The magnitude of the magnetic flux is adjusted by controlling the flowing current. That is, when the field current is small, the output of the generator 3 is small and the voltage between the terminals of the generator 3 is also low. On the other hand, when the field current is large, the output of the generator 3 is large and the generator 3 is large. The inter-terminal voltage also increases. The field winding 3c is connected to the power shaft of the engine via a pulley or a belt, and the speed at which the magnetic flux changes is proportional to the engine speed.

  FIG. 2 is a graph showing the voltage between the terminals of the generator 3 when the field current and the engine speed are changed. In the graph of FIG. 2, the horizontal axis represents the engine speed, and the vertical axis represents the voltage between the terminals of the generator 3. If1, If2, and If3 are three types of field currents. The field currents If1, If2, and If3 have different values and have a relationship of If3> If2> If1. In FIG. 2, VB is a voltage between the terminals of the first battery 1, and a region where the voltage between the terminals of the generator 3 is equal to or higher than the voltage VB between the terminals of the first battery 1 is referred to as a “normal power generation operation region”. A region where the voltage between the terminals of the generator 3 is less than the voltage VB between the terminals of the first battery 1 is referred to as a “low-efficiency power generation operation region”. In the “low efficiency power generation operation region”, the power generation efficiency of the generator 3 is controlled by controlling the field current so that the voltage between the terminals of the generator 3 satisfies the predetermined condition and the engine speed satisfies the predetermined condition. However, power generation is performed while adjusting so that the efficiency becomes lower than a predetermined value set in advance.

  As shown in FIG. 2, when the field current is If3, the voltage between the terminals of the generator 3 can be made higher than when the field current is If1 or If2. Usually, since the current flows from a high potential to a low potential, the voltage between the terminals of the generator 3 must be higher than the voltage VB between the terminals of the first capacitor 1 in order for the first capacitor 1 to be charged. I must. The field current is obtained by PID control based on the inter-terminal voltage VB of the first battery 1 and the target voltage, and is controlled so that the inter-terminal voltage VB of the first battery 1 becomes the target voltage. Hereinafter, the operation of controlling the field current so that the voltage between the terminals of the first capacitor 1 becomes the target voltage is referred to as “normal power generation operation” in the “normal operation mode”. In the normal power generation operation, energization from the first capacitor 1 to the armature winding 3b is not performed, and all the semiconductor elements of the rectifier circuit 3a are turned off. The electric power generated in the armature winding 3b is output to the first battery 1 through the diode of the rectifier circuit 3a, and the first battery 1 is charged. When the generator 3 is in a normal power generation operation, the rotation energy is converted into electric energy, and the torque generated during the normal power generation has a magnitude corresponding to the output power. The “power generation prohibiting operation” in the “normal operation mode” is defined as an operation for prohibiting normal power generation. However, even in the state where normal power generation is prohibited, it is not included in the “power generation prohibition operation” in the voltage reduction operation mode (low efficiency power generation operation and armature winding energization operation).

  On the other hand, in the state where the field current is If1 or the field current is If2 and the engine speed is less than a predetermined NALT, the voltage between the terminals of the generator 3 is the voltage between the terminals of the first battery 1. Since it becomes lower than VB, the 1st battery 1 will be in a discharge state. As a result, the field current flowing through the field winding 3c for the purpose of generating electric power is obtained from the first capacitor 1 and consumed inside the generator 3. Hereinafter, such a state is referred to as “low efficiency power generation operation”. The low-efficiency power generation operation is a normal power generation operation because the voltage between the terminals of the generator 3 increases even when the field current is small in a region where the engine speed is high. Therefore, in order to maximize the field current during the low-efficiency power generation operation, it is necessary to control the field current so as to satisfy the limit based on the voltage across the generator 3 and the limit based on the engine speed. There is. In the low-efficiency power generation operation, energization from the first capacitor 1 toward the armature winding 3b is not performed, and all the semiconductor elements of the rectifier circuit 3a are turned off. Most of the electric energy input during the low-efficiency power generation operation is used to generate magnetic flux in the field winding 3c, and a part is consumed as heat. Since no current flows through the armature winding 3b, there is no magnetic flux perpendicular to the magnetic flux generated in the field winding 3c, and no power generation operation occurs. There are very few.

  Next, the “armature winding energization operation” is defined as follows. In the armature winding energization operation, the field winding 3c of the generator 3 is made non-conductive, and only the armature winding 3b of the generator 3 is energized to reduce the voltage across the terminals of the first capacitor 1. Is the action. At this time, no field current flows because the field winding 3c is not energized. Hereinafter, in order to make the description easy to understand, the upper arm semiconductor elements constituting the rectifier circuit 3a will be described as Tr1, Tr2, Tr3, and the lower arm semiconductor elements will be described as Tr4, Tr5, Tr6. The ON state and the OFF state are switched so that the semiconductor elements Tr1 to Tr6 of the rectifier circuit 3a are not vertically short-circuited. Specifically, the upper and lower short circuits are prevented from being short-circuited by not simultaneously turning on both of the corresponding semiconductor elements of the upper arm and the lower arm. As shown in FIG. 1, when the armature winding 3b has three phases, two of the three winding ends opposite to the neutral point where the three armature windings are connected are moved to the plus side, and the remaining The semiconductor element at the corresponding location is turned on so that one is connected to the minus side. For example, Tr1: ON, Tr2: ON, Tr3: OFF, Tr4: OFF, Tr5: OFF, Tr6: ON. Thus, the armature winding 3b can be energized by switching between semiconductor conduction and non-conduction. Note that the combination of energization / non-energization of the semiconductor elements is merely an example, and it is sufficient that the armature winding 3b can be energized so as not to cause a vertical short circuit, and is not limited to the above combinations.

  During the armature winding energization operation, no field current is passed, so no power generation operation is performed. Further, since a current flows through the armature winding 3b in the direction opposite to the charging operation, the generator 3 consumes external power. Most of the electric energy input during the armature winding energization operation is used to generate magnetic flux, and a part is consumed as heat. Since no current flows through the field winding 3c, there is no magnetic flux perpendicular to the magnetic flux generated in the armature winding 3b, and no power generation operation is performed. Therefore, the torque generated during the armature winding energization operation is Zero or very little.

  As described above, in the first embodiment of the present invention, as a method of reducing the voltage between the terminals of the first capacitor 1, the low efficiency executed when the generator 3 is set in the voltage reduction operation mode. Two types of operations are defined: a power generation operation and an armature winding energization operation. Each operation has been described above, and each has the following characteristics.

The armature winding energization operation has the following characteristics.
-Since the electric power stored in the 1st electrical storage device 1 is consumed while flowing a big electric current with the generator 3, the voltage between the terminals of the 1st electrical storage device 1 can be reduced greatly in a short time.
Since there is simple power consumption at the armature winding 3b, there is no limit to the voltage that can be reduced.
-Since only the energization state to the armature winding 3b is switched, the degree of voltage drop and the amount of flowing current cannot be adjusted.
-Although the generator 3 is motively connected with the engine, it can be regarded as the electric power consumption by the armature winding 3b, and operation | movement is not restrict | limited by the rotation speed.
-A large current flows during operation, and the temperature inside the generator 3 rises, so it cannot be used in a region above a predetermined temperature.

The low-efficiency power generation operation has the following characteristics.
In general, the field winding 3c is designed to have a large number of turns in order to generate a large magnetic flux, and since the resistance is larger than that of the armature winding 3b, the flowing current is reduced. The voltage between terminals cannot be greatly reduced in a short time.
Since there is power consumption in the field winding 3c, there is no limit to the voltage that can be reduced.
As an original function of the generator 3, the amount of current flowing through the field winding 3c can be controlled, so that the degree of voltage drop and the amount of flowing current can be adjusted even during low-efficiency power generation operation. it can.
-Since it is motively connected to the engine and generates power in the high speed region, it cannot be operated with low efficiency depending on the engine speed.
-Since the temperature inside the generator rises during operation, it cannot be used in the area above the specified temperature.
-The normal power generation operation can be performed only by increasing the flowing field current, so that the transition to the normal power generation operation is easy.

  As described above, since the methods for reducing the voltage across the terminals of the first battery 1 have characteristics, it is desirable to select a method according to the state of the vehicle, the engine, and the power system. In other words, when the potential difference is large and the engine speed is high, the armature winding energization operation is selected. When the potential difference is small and the engine speed is low, the low-efficiency power generation operation is selected. Can be an appropriate operation.

  FIG. 3 is a time chart showing the operation of the power management apparatus and its peripherals according to Embodiment 1 of the present invention. The horizontal axis of the graph is the time axis, and the vertical axis represents the idling stop permission / prohibition signal generated by the power management unit 7 and the first switch signal for switching between conduction / non-conduction of the first switch 6 from the upper stage, respectively. (Switching signal), fuel injection signal indicating the presence or absence of fuel injection from the injector 13, vehicle speed indicating the traveling speed of the vehicle, engine speed detected by the engine speed detection means 11, and voltage across the terminals of the first battery 1 , The voltage across the second capacitor 2, the current flowing through the field winding 3c of the generator 3 (generator field current), the current flowing through the armature winding 3b of the generator 3 (generator armature current) , Current of the generator 3 (generator current), torque applied to the power generation of the generator 3 (power generation torque), engine output torque (engine output torque), power converter 4 output current (power converter current), power source Of the management unit 7 Power / generator prohibits the operation command indicating to electric 3 (generator power generation command), representing the ON / OFF of the voltage drop operation modes of the generator 3. Note that the voltage reduction operation mode of the generator 3 includes two types of operations, namely, the armature winding energization operation and the low-efficiency power generation operation described above, as shown in FIG. Further, when the voltage reduction operation mode of the generator 3 is OFF, the normal operation mode is set. Further, the armature current of the generator 3 is a positive value during power generation, and is a negative value when power is consumed by the armature winding 3b. Similarly, it is assumed that the current of the generator 3 shows a positive value during power generation, and shows a negative value when power is consumed by the generator 3. In the example of FIG. 3, for the sake of simplicity of explanation, it is assumed that a failure of the power converter 4 has occurred during slow deceleration, and the operation when idling is continued thereafter will be described. However, this time chart is used to explain the operation principle of the present invention, and the scope of the present invention is not limited to this operation range. Further, the current and torque characteristics of the generator are merely examples, and are not limited to the characteristics of the time chart shown in FIG.

  As shown in FIG. 3, before time t = T301, as can be seen from the value of the output current (power converter current) of the power converter 4, the power converter 4 is operating normally, and the failure is It has not occurred. Further, as indicated by the vehicle speed, the vehicle is slowly decelerating, and the engine speed is gradually approaching a predetermined idling speed. However, it is outside the control range in which fuel injection is stopped during deceleration, and fuel is injected by the injector 13 as indicated by the fuel injection signal. The generator 3 is in a power generation state in accordance with an operation command (generator power generation command) of the power management unit 7 and is controlled so that the voltage between the terminals of the first battery 1 is constant. The electric power of the first battery 1 is supplied to the second battery 2 and the vehicle accessories 5 via the power converter 4, but the first battery 1 and the second battery 2 are sufficient. The voltage between the terminals of the second battery 2 is also maintained at a constant value. The electric current of the generator 3 (generator current) flows only for the electric power for driving the auxiliary machinery 5 of the vehicle connected to the power converter 4. The engine output torque (engine output torque) generates a torque necessary for rotating the engine itself and a torque necessary for power generation. The power converter 4 is operating normally as described above, and outputs a current necessary for driving the auxiliary machinery 5 of the vehicle to the low voltage circuit.

  In the vicinity of time t = T301, a failure of the power converter 4 occurs due to some cause. The output current of the power converter 4 decreases and eventually becomes zero. Since there is no power supply from the high voltage circuit, power is supplied from the second battery 2 to the auxiliary machinery 5 of the vehicle, as shown in the voltage across the terminals of the second battery in FIG. In addition, the voltage across the terminals of the second battery 2 gradually decreases. When the voltage between the terminals of the second capacitor 2 becomes equal to or lower than the drive limit voltage of the auxiliary machinery 5, the auxiliary machinery 5 of the vehicle cannot be driven, and the vehicle may not be able to travel. It is also desirable that the power supply be resumed as quickly as possible to the auxiliary equipment 5 of the vehicle. Based on the output value of the power converter output current detection means 10, the power management unit 7 detects that the current of the power converter 4 has decreased and detects a failure of the power converter 4. When detecting a failure of the power converter 4, the power management unit 7 prohibits the engine control device 14 from idling stop and instructs the generator 3 to perform a power generation prohibiting operation. Thereby, the power generation current and power generation torque of the generator 3 are reduced to zero. Since the electric power stored in the first battery 1 is not consumed and stored, the voltage between the terminals of the first battery 1 maintains a constant value. After detecting the failure, the power management unit 7 holds this operation for a predetermined time (between time T301 and time T302). This is because the current of the generator 3 is suddenly cut off, so that the voltage fluctuation caused by the current that has lost its place of stabilization is stabilized, or the current flowing through the field winding 3c is stabilized near zero. The purpose is to suppress malfunction.

  The power management unit 7 sets a first predetermined voltage range based on the voltage between the terminals of the second battery 2 as a determination value for switching the first switch 6 from the non-conductive state to the conductive state, and the first switch 6 The first predetermined threshold voltages T1H and T1L are calculated as the upper limit value and the lower limit value of the predetermined voltage range. The first predetermined threshold voltage T1H is larger than the voltage between the terminals of the second battery 2 by a predetermined value D1, while the first predetermined threshold voltage T1L is higher than the voltage between the terminals of the second battery 2. The value is smaller by a predetermined value D2. Therefore, the difference between the first predetermined threshold voltages T1H and T1L is (D1 + D2), and the range of (D1 + D2) with respect to the voltage across the terminals of the second battery 2 is the above-mentioned first predetermined voltage range. Become. The values of D1 and D2 may be the same or different. When the potential difference between the value of the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 falls within the predetermined range, the power management unit 7 turns off the first switch 6. Switch from state to conduction. Note that the values of the first predetermined threshold voltages T1H and T1L are the limits at which no failure occurs due to the current generated by the potential difference between the first capacitor 1 and the second capacitor 2 when the first switch 6 is turned on. The potential difference is calculated based on the voltage between the terminals of the second battery 2. When the voltage between the terminals of the first battery 1 is higher than the first predetermined threshold voltage T1H, the power management unit 7 starts a process of reducing the voltage between the terminals of the first battery 1. Further, when the voltage between the terminals of the first capacitor 1 is lower than the first predetermined threshold voltage T1L, the power management unit 7 starts a process of increasing the voltage between the terminals of the first capacitor 1. When the voltage between the terminals of the first capacitor 1 is higher than the first predetermined threshold voltage T1L and lower than the first predetermined threshold voltage T1H, that is, the voltage between the terminals of the first capacitor 1 and the second capacitor When the potential difference with the voltage between the two terminals is within the first predetermined voltage range, the current between the terminals of the first capacitor 1 is adjusted because a current large enough to cause a failure of the first switch 6 does not flow. The first switch 6 can be turned on without doing so.

  At time t = T302, since the voltage between the terminals of the first capacitor 1 is higher than the first predetermined threshold voltage T1H, the power management unit 7 starts a process of reducing the voltage between the terminals of the first capacitor 1. To do. Specifically, the operation of the generator 3 is changed to the voltage reduction operation mode. Next, it is determined whether the voltage drop operation mode is switched to the low efficiency power generation operation or the armature winding energization operation. Since the current engine speed is equal to or higher than the predetermined engine speed N1 and is not suitable for the low-efficiency power generation operation, the armature winding energization operation is commanded to the generator 3. Thereafter, energization to the armature winding 3b is started, and the electric power of the first capacitor 1 is consumed by the armature winding 3b, and the voltage between the terminals of the first capacitor 1 is lowered. During this time, the field current control circuit 3d of the generator 3 is instructed not to energize the field winding 3c, and no power generation torque is generated, so the engine output torque necessary for power generation does not increase. Here, the predetermined engine speed N1 is an engine speed at which the generator 3 can be operated in the low efficiency region at the current engine speed, and the power consumption in the generator 3 is equal to or greater than a predetermined value.

  At time t = T303, the power management unit 7 determines that the voltage between the terminals of the first battery 1 is higher than the first predetermined threshold voltage T1H and the engine speed is less than the predetermined engine speed N1. The power management unit 7 changes the command for the generator 3 from the armature winding energization operation to the low efficiency power generation operation. In the low-efficiency power generation operation, the field current is gradually increased and power is consumed inside the generator 3. As a result, the voltage between the terminals of the first battery 1 is decreased, the potential difference from the voltage between the terminals of the second battery 2 is reduced, and the current consumption in the generator 3 is reduced.

  At time t = T304, the power management unit 7 decreases the voltage between the terminals of the first capacitor 1 to be equal to or lower than the first predetermined threshold voltage T1H, and the voltage between the terminals of the first capacitor 1 and the second capacitor 2 It is determined that the potential difference between the terminals is within the first predetermined voltage range. The power management unit 7 commands the first switch 6 to switch from the non-conducting state to the conducting state, and the first switch 6 becomes the conducting state. Thereby, a current flows from the first capacitor 1 to the second capacitor 2, and the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 become equal. The current of the generator 3 outputs a current necessary for maintaining the voltage between the terminals of the first capacitor 1 and the second capacitor 2 and a current supplied to the auxiliary machinery 5 of the vehicle. The power generation torque of the power generator 3 is a torque corresponding to the power generation amount of the power generator 3. The engine output torque is a sum of the power generation torque of the generator 3 and the torque necessary to maintain the engine rotation. The operation command of the generator 3 is switched from the low-efficiency power generation operation to the normal power generation operation after the first switch 6 is turned on, and supplies power to the auxiliary machinery 5 and the second battery 2 of the vehicle. .

  4A and 4B are flowcharts showing the operation of the power management unit 7 according to the first embodiment of the present invention.

  First, in step S401, it is determined whether or not a failure of the power converter 4 has occurred. Specifically, the voltage detected by the inter-terminal voltage detection means 7a of the first capacitor 1 is equal to or higher than the drive lower limit voltage of the power converter 4, and the power converter 4 is in a drivable state. When the output current of the power converter 4 measured by the power converter output current detection means 10 is equal to or lower than the minimum current during normal driving, it is determined that there is a failure, and the process proceeds to step S402. Ends the processing as it is.

  In step S402, a power generation prohibition operation is commanded to the generator 3, and the process proceeds to step S403.

  In step S403, the engine control device 14 is instructed to prohibit idling stop, and the process proceeds to step S404.

  In step S404, an elapsed time from the time when the failure is detected is measured, and when a predetermined time has elapsed, the process proceeds to step S405. Thereby, the previous operation is held for the predetermined time.

  In step S405, it is determined whether or not the difference between the terminal voltage of the first capacitor 1 and the terminal voltage of the second capacitor 2 is within a preset first predetermined voltage range. That is, if the voltage between the terminals of the first capacitor 1 is equal to or lower than the first predetermined threshold voltage T1H and equal to or higher than the first predetermined threshold voltage T1L, the process proceeds to step S421, while the second capacitor 2 If the potential difference from the inter-terminal voltage is outside the first predetermined voltage range, the process proceeds to step S406.

  In step S406, the voltage across the terminals of the first battery 1 detected by the voltage across the terminals 7a of the first battery 1 is detected by the voltage across the terminals 7b of the second battery 2 detected by the second battery. It is determined whether the voltage is less than the voltage between terminals. When the voltage between the terminals of the first capacitor 1 is equal to or lower than the voltage between the terminals of the second capacitor 2, the process proceeds to step S419, while the voltage between the terminals of the first capacitor 1 is equal to the terminal of the second capacitor 2. If it is higher than the inter-voltage, the process proceeds to step S407.

  In step S407, the power management unit 7 switches the operation mode of the generator 3 from the normal operation mode to the voltage reduction operation mode, and proceeds to step S408.

  In step S408, it is determined whether or not the engine speed is equal to or higher than a predetermined engine speed N1. If it is greater than or equal to the predetermined engine speed N1, the process proceeds to step S409, and if it is less than the predetermined engine speed N1, the process proceeds to step S413.

  In step S409, the power management unit 7 sets the operation of the generator 3 to the armature winding energization operation, and proceeds to step S410.

  In step S410, it is determined whether the temperature of the generator 3 measured by the thermistor 3e is higher than a second predetermined temperature set in advance. The second predetermined temperature is set to a value obtained by experiment to determine the maximum temperature at which the generator 3 does not fail when the armature winding 3b is energized. If the temperature is equal to or lower than the second predetermined temperature, the process proceeds to step S411. If the temperature is higher than the second predetermined temperature, the process proceeds to step S412.

  In step S411, the power management unit 7 energizes the armature winding 3b. After energizing the armature winding 3b, the process returns to step S405 and continues.

  In step S412, since the temperature of the generator 3 measured by the thermistor 3e is high, all the semiconductor elements of the rectifier circuit 3a are turned OFF to prohibit energization of the armature winding 3b, and the process returns to step S405 to perform the processing. to continue.

  In step S413, the power management unit 7 sets the operation of the generator 3 to the low-efficiency power generation operation, and proceeds to step S414.

  In step S414, it is determined whether or not the temperature of the generator 3 is higher than the first predetermined temperature. The first predetermined temperature is set to a value obtained by experiment to determine the maximum temperature at which the generator 3 does not fail while the field winding 3b is energized. If the temperature is equal to or lower than the first predetermined temperature, the process proceeds to step S415. If the temperature is higher than the first predetermined temperature, the process proceeds to step S417.

  In step S415, the power management unit 7 calculates a field current limit value that limits the current flowing through the field winding 3c so as to achieve a low-efficiency power generation operation, and the process proceeds to step S416. The field current limit value is obtained by a look-up table using the engine speed and the voltage between terminals of the generator 3 as arguments. An example of setting the table is shown in FIG. Each field current has a relationship of If3> If2> If1. In this setting example, in a region where the engine speed is low and the inter-terminal voltage of the generator 3 is high, the limit value increases so as to increase the field current that can flow, the engine speed is high, and the inter-terminal voltage of the generator 3 is increased. In a low region, the limit value becomes small so as to reduce the field current that can flow.

  In step S416, the field current command value is calculated, and the process proceeds to step S418. The calculation of the field current command value is calculated using the following equation.

 Field current command value = MIN (field current command value (previous value) + field current increase, field current limit value)

  However, MIN (A, B) represents a function that returns the minimum value of A and B. The initial value of the field current command value is 0 [A].

  In step S417, the field current command value is set to 0 [A], and the process proceeds to step S418.

  In step S418, the field current command value calculated by the power management unit 7 in the process of step S416, or the field current command value (0 [A]) set by the power management unit 7 in the process of step S418. To the field current control circuit 3d. The field current control circuit 3d performs control so that the commanded field current is obtained, returns to step S405, and continues the processing.

  In step S419, the power management unit 7 instructs the generator 3 to perform a normal power generation operation, and the process proceeds to step S420.

  In step S420, it is determined whether the voltage between the terminals of the first battery 1 is within the first predetermined voltage range. If the voltage between the terminals of the first capacitor 1 is not more than the first predetermined threshold voltage T1H and is within the first predetermined voltage range that is not less than the first predetermined threshold voltage T1L, the process proceeds to step S421. If it is outside the predetermined voltage range of 1, the process proceeds to step S419.

  In step S421, the power management unit 7 instructs the first switch 6 to switch from the non-conducting state to the conducting state, and ends the process.

  As described above, the power management device according to Embodiment 1 of the present invention converts the electric power of the first battery 1, the second battery 2, and the first battery 1 to convert the second battery 2 and A power converter 4 to be supplied to the auxiliary machinery 5 of the vehicle, a generator 3 connected to the first capacitor 1 and generating power by external torque to charge the first capacitor 1, and the first capacitor 1 are included. The first switch 6 is connected between the circuit and the circuit including the second capacitor 2 and switches the circuit between the non-conducting state and the conducting state when the power converter 4 fails. Before switching from the non-conductive state to the conductive state, the generator 3 is in the power generation operation mode so that the voltage difference between the terminals of the first capacitor 1 and the second capacitor 2 is within the first predetermined voltage range. It is configured to operate as another voltage reduction operation mode in which power is consumed inside the generator 3 . As described above, in the power management device according to the first embodiment of the present invention, when a failure occurs in the power converter 4, the first switch 6 provided between the high voltage circuit and the low voltage circuit. Is configured to be switched to a conductive state, so that even when a failure of the power converter 4 occurs, the power generated by the generator 3 can be supplied to the auxiliary machinery 5 of the vehicle. The traveling can be stably continued without stopping the auxiliary machinery 5 of the vehicle. In addition, since only the first switch 6 is provided, it is possible to reduce the cost and size as compared with the case of dual system. Further, since the first switch 6 is switched to the conductive state after the potential difference between the high voltage circuit and the low voltage circuit is within the first predetermined voltage, a large current flows through the first switch 6 and the first switch 6 is turned on. It is possible to prevent the switch 6 from being burned out, and without causing the voltage of the low-voltage circuit to rise, it is possible to prevent burning beyond the withstand voltage of the auxiliary equipment 5 of the vehicle.

  Further, when the voltage reduction operation mode is set when the voltage between the terminals of the first battery 1 is higher than the predetermined threshold voltage TH1 and the engine speed is lower than the predetermined engine speed N1, the generator 3 is made efficient. A low-efficiency power generation operation is performed in which power is generated in a low region and the voltage of the first battery is lowered. Thereby, the voltage between the terminals of the first battery 1 can be reduced with a slight change in the program without adding special equipment, and the magnitude of the current when the voltage is reduced can be controlled. Therefore, the voltage between the terminals of the first battery 1 can be quickly converged to the target voltage.

  Further, when the temperature of the generator 3 measured by the thermistor 3e is equal to or higher than the first predetermined temperature, the low efficiency power generation operation is stopped. Thereby, even when the generator 3 is caused to generate power in a low-efficiency region, a failure due to a temperature rise of the generator 3 can be prevented.

  Further, in the voltage lowering operation mode, when the voltage between the terminals of the first battery 1 is higher than the first predetermined threshold voltage T1H, the field winding 3c of the generator 3 is deenergized, and the generator 3 The armature winding energization operation in which only the armature winding 3b is energized to reduce the voltage across the terminals of the first battery 1 is performed. As a result, the voltage across the terminals of the first battery 1 can be reduced by a slight change in the program without adding special equipment, and even in an engine state where a low-efficiency power generation operation cannot be performed. The terminal voltage of the first battery 1 can be quickly reduced.

  Further, when the temperature of the generator 3 is equal to or higher than the second predetermined temperature, the armature winding energization operation is stopped. As a result, even if the armature winding 3b of the generator 3 is energized to reduce the voltage across the terminals of the first capacitor 1, a failure due to the temperature rise of the generator 3 is prevented in advance. can do.

  Further, in the voltage reduction operation mode, when the voltage between the terminals of the first capacitor 1 is higher than the predetermined threshold voltage TH1, the generator 3 is caused to generate power in a low efficiency region and the voltage between the terminals of the first capacitor 1 is set. The low-efficiency power generation operation, which is power generation in a low-efficiency region, and the field winding 3c of the generator 3 is de-energized, and only the armature winding 3b of the generator 3 is energized, The armature winding energization operation for reducing the voltage between the terminals of the battery 1 is switched. Thereby, since it becomes possible to select an optimal voltage reduction operation mode according to the operating state of the engine, the voltage across the terminals of the first battery 1 can be quickly reduced.

  In the voltage reduction operation mode, the low-efficiency power generation operation and the armature winding energization operation are switched according to the predetermined engine speed N1. Thereby, since it can switch to the optimal voltage reduction operation mode according to the rotation speed of the engine, the voltage between the terminals of the first battery 1 can be more reliably reduced and converged when a failure occurs.

  In addition, the configuration is such that after the failure of the power converter 4 is detected and before the first switch 6 is switched from the non-conducting state to the conducting state, the change in torque generated by the generator 3 is controlled to a predetermined value or less. It was. Thereby, since the torque fluctuation at the time of failure can be suppressed, the uncomfortable feeling to the driver can be suppressed.

  In the description of the first embodiment described above, the operation performed in the voltage reduction operation mode has been described as including two types of the armature winding energization operation and the low-efficiency power generation operation. Only one of them may be included. In that case, regardless of the engine speed, the power management unit 7 determines that the potential difference between the terminal voltage of the first battery 1 and the voltage between the terminals of the second battery 2 is outside the first predetermined voltage range. In addition, when it is determined that a predetermined condition that the voltage between the terminals of the first battery 1 is higher than the voltage between the terminals of the second battery 2 is included, either one included in the voltage reduction operation mode (That is, the armature winding energization operation or the low-efficiency power generation operation) may be performed.

Embodiment 2. FIG.
A power management apparatus according to Embodiment 2 of the present invention will be described below with reference to the drawings. In each figure, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 5 is a configuration diagram showing the configuration of the power management apparatus according to the second embodiment of the present invention and its periphery. The difference from the first embodiment shown in FIG. 1 is that in FIG. 5 showing the second embodiment, the third battery 9, the terminal voltage detection means 7c of the third battery 9, and the first The second switch 8 is added. The terminal voltage detection means 7 c of the third battery 9 is installed inside the power management unit 7 and measures the voltage across the terminals of the third battery 9. Further, the third battery 9 is connected to the first battery 1 in parallel. The third capacitor 9 is used as a backup at the time of failure, and is connected to the first capacitor 1 when a failure is detected. The second switch 8 is connected between the first capacitor 3 and the third capacitor 9, and is normally in a non-conductive state between them, and a predetermined condition is established in the power management unit 7. In this case, a switching command (second switching command) is output from the power management unit 7, whereby the second switch 8 is turned on, and the first capacitor 3 and the third capacitor 9 become conductive. .

  In the first embodiment, it has been described that the operation mode of the generator 3 includes two modes of the normal operation mode and the voltage reduction operation mode. In the second embodiment, these two modes are described. In addition to the mode, there is also a reserve capacitor charging mode.

  “Preliminary capacitor charging mode” means that the second switch 8 is switched to the conductive state to connect the first capacitor 1 and the third capacitor 9 to the third capacitor 9 provided as a spare capacitor. This is a mode for performing a charging operation (“preliminary capacitor charging operation”). In the second embodiment, the power management unit 7 uses the second predetermined voltage range set to be wider than the first predetermined voltage range described in the embodiment as a determination value, and uses the power converter 4 When a failure is detected, the difference between the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 is outside the second predetermined voltage range and between the terminals of the first capacitor 1 When the voltage is higher than the voltage between the terminals of the second capacitor 2, the second switch 8 is output to the second switch 8, thereby connecting the first capacitor 1 and the third capacitor 9. The third battery 9 is charged as a state (preliminary battery charging operation). When the power management unit 7 detects that the inter-terminal voltage of the first battery 1 and the inter-terminal voltage of the third battery 9 are equalized by performing the reserve battery charging operation, the first embodiment Switch to the voltage drop operation mode described in. Thus, in the second embodiment, when the potential difference between the terminal voltage of the first capacitor 1 and the second terminal voltage is large, the electric power stored in the first capacitor 1 is the third The second embodiment is different from the first embodiment in that the armature winding energization operation or the low-efficiency power generation operation in the voltage lowering operation mode is performed after moving to the capacitor 9 and reducing the voltage between the terminals of the first capacitor 1 to some extent. Other processes and other configurations are the same as those in the first embodiment.

  The power management device according to Embodiment 2 of the present invention includes a power management unit 7, a first switch 6, a third capacitor 9, and a second switch 8. Further, the power management system according to Embodiment 1 of the present invention includes a first capacitor 1, a second capacitor 2, a third capacitor 9, a power converter 4, a generator 3, a first switch 6, a first switch 2 switches 8 and a power management unit 7. The power converter output current detection means 10 may also be a component of the power management device. Furthermore, the present invention is also a power management method implemented by the power management apparatus or power management system.

  FIG. 6 is a time chart showing the operation of the power management apparatus according to the second embodiment of the present invention and its surroundings. In FIG. 6, the horizontal axis is the time axis as in FIG. The difference between FIG. 6 and FIG. 3 is that in FIG. 6, the second switch signal (second switching command) for switching conduction / non-conduction of the second switch 8 and the third battery 9 are plotted on the vertical axis. The voltage between terminals is added. Others are the same as FIG.

  Prior to time t = T601, as can be seen from the current value of the power converter 4 in FIG. 6, the power converter 4 is operating normally and no failure has occurred. Further, as shown in the vehicle speed of FIG. 6, the vehicle is slowly decelerating, and the engine speed is gradually approaching a predetermined idling speed. However, the fuel is injected from the injector 13 as indicated by the fuel injection signal because it is outside the control range in which the fuel injection is stopped at the time of deceleration. The generator 3 is in a normal power generation state according to the generator power generation command, and is controlled so that the voltage between the terminals of the first capacitor 1 is constant. The electric power of the first battery 1 is supplied to the second battery 2 and the vehicle accessories 5 via the power converter 4, but the first battery 1 and the second battery 2 are sufficient. The terminal voltage is maintained at a constant value. The electric current of the generator 3 flows only for the electric power required to drive the auxiliary machinery 5 of the vehicle connected to the power converter 4. The output torque of the engine generates a torque necessary for rotating the engine itself and a torque necessary for power generation. The power converter 4 is operating normally, and outputs a current necessary for driving the auxiliary machinery 5 of the vehicle to the low voltage circuit.

  In the vicinity of time t = T601, a failure of the power converter 4 occurs due to some cause. The output current of the power converter 4 decreases and eventually becomes zero. As a result, there is no power supply from the high voltage circuit, so that power is supplied from the second battery 2 to the auxiliary machinery 5 of the vehicle, and the voltage across the terminals of the second battery 2 gradually increases. It goes down. When the voltage between the terminals of the second battery 2 is equal to or lower than the drive limit voltage of the auxiliary machinery 5 of the vehicle, the auxiliary machinery 5 of the vehicle cannot be driven, and the vehicle may not be able to travel. It is desirable that the power supply be resumed as quickly as possible to the battery 2 and the vehicle accessories 5. When detecting a failure of the power converter 4, the power management unit 7 outputs a command for prohibiting idling stop to the engine control device 14 and commands a power generation prohibiting operation to the generator 3. Thereby, the power generation current and power generation torque of the generator 3 are reduced to zero. Since the electric power stored in the first battery 1 is not consumed or stored, the voltage between the terminals maintains a constant value. After detecting the failure, the power management unit 7 holds the operation for a predetermined time (between time T601 and time T602). This is because the current of the generator 3 is suddenly cut off, so that the voltage fluctuation caused by the current that has lost its place of stabilization is stabilized, or the current flowing through the field winding 3c is stabilized near zero. The purpose is to suppress malfunction.

  The power management unit 7 calculates the second predetermined threshold voltage T2 as a determination value for switching the second switch 8 from non-passage to conduction. The second predetermined threshold voltage T2 is obtained by switching the second switch 8 from the non-passing state to the conducting state and calculating the voltage when the voltage between the terminals of the first capacitor 1 is stabilized from the current voltage. Thus, the voltage between the terminals of the first battery 1 after the second switch 8 is turned on is a value for determining whether or not the voltage between the terminals of the second battery 2 is higher. If the voltage when the voltage between the terminals of the first capacitor 1 is stabilized becomes an extremely low value compared to the voltage between the terminals of the second capacitor 2, the voltage between the terminals of the first capacitor 1 is The voltage between the terminals of the second battery 2 needs to be increased by the power generation operation, and the voltage reduction operation mode is executed without bringing the second switch 8 into the conducting state, so that the voltage between the terminals of the first battery 1 is It may take longer than when reducing The determination based on the second predetermined threshold voltage T2 aims to prevent a time loss during this period.

  Hereinafter, a method for calculating the second predetermined threshold voltage T2 will be described. First, a voltage drop Vd assumed when the second switch 8 is switched from the non-passing state to the conducting state is calculated. Vd is obtained from the capacities of the first capacitor 3 and the third capacitor 9 and the voltage between the terminals. For the sake of simplicity, it is assumed that the first capacitor 3 and the third capacitor 9 are both capacitors, and that the power loss in the conductor is ignored. The charge amount Q1 stored in the first capacitor 1 and the charge amount Q3 stored in the third capacitor 9 are obtained by the following equations.

Charge amount Q1 stored in first capacitor 1
= Capacitance C1 of the first capacitor 1 × terminal voltage V1 of the first capacitor 1

Charge amount Q3 stored in third capacitor 9
= Capacitance C3 of the third capacitor 9 × terminal voltage V3 of the third capacitor 9

  Therefore, the voltage V13 when the first capacitor 3 and the third capacitor 9 are connected in parallel can be expressed by the following equation.

V13 = (Q1 + Q3) / (C1 + C3)
= ((C1 × V1) + (C3 × V3)) / (C1 + C3)

  Therefore, Vd becomes the following equation.

  Vd = terminal voltage V1−V13 of the first battery 1

  As described above, the second predetermined threshold voltage T2 is calculated using the following equation.

  T2 = terminal voltage V2 + Vd of the second battery 2

  Thus, T2 is defined. In the present embodiment, when the terminal voltage of the first battery 1 is higher than T2, that is, the potential difference between the terminal voltage of the first battery 1 and the terminal voltage of the second battery 2 is 0 to Vd. And when the voltage between the terminals of the first capacitor 1 is higher than the voltage between the terminals of the second capacitor 2, the second switch 8. Is switched from the non-conductive state to the conductive state. As shown in FIG. 6, the second predetermined voltage range is wider than the first predetermined voltage range (Vd> D1).

  At time t = T602, the power supply management unit 7 detects that the voltage between the terminals of the first capacitor 1 is equal to or higher than the second predetermined threshold voltage T2, and connects the third capacitor 9 with the first capacitor 1. In order to set the conductive state, the second switch 8 is switched from the non-conductive state to the conductive state. By setting the second switch 8 to the conductive state, the electric power stored in the first capacitor 1 flows to the third capacitor 9, so that the voltage across the terminals of the first capacitor 1 decreases and the third The voltage of the first capacitor 1 and the third capacitor 9 are equal after a predetermined time (specifically, after the time from time T602 to time T603 has elapsed). Hence, no potential difference is generated between the first capacitor 3 and the third capacitor 9 thereafter. The generator 3 is in a power generation prohibition operation until the potential difference disappears after the first switch 3 and the third battery 9 are turned on by the second switch 8, so that no power generation torque is generated.

  At time t = T603, the power management unit 7 detects that the voltages of the first capacitor 3 and the third capacitor 9 are equal. At this time, since the voltage between the terminals of the first battery 1 is higher than the first predetermined threshold voltage T1H, the power management unit 7 starts a process of reducing the voltage between the terminals of the first battery 1. That is, the operation of the generator 3 is changed to the voltage reduction operation mode. Next, it is determined whether the voltage drop operation mode is switched to the low efficiency power generation operation or the armature winding energization operation. Since the current engine speed is equal to or higher than the predetermined engine speed N1, the armature winding energizing operation is commanded to the generator 3. After that, energization to the armature winding 3b is started, and the electric power of the first capacitor 1 and the third capacitor 9 is consumed by the armature winding 3b, and the voltage between these terminals decreases. To go. During this time, the field current control circuit 3d of the generator 3 is instructed not to energize the field winding 3c, and no power generation torque is generated, so the engine output torque necessary for power generation does not increase. . Here, the predetermined engine speed N1 is an engine speed at which the generator 3 can be operated in a low-efficiency region at the current engine speed and the power consumption in the generator 3 is equal to or greater than a predetermined value.

  At time t = T604, the power management unit 7 determines that the voltage between the terminals of the first battery 1 is higher than the first predetermined threshold voltage T1H, and the engine speed is less than the predetermined engine speed N1. As a result, the power management unit 7 changes the command to the generator 3 from the armature winding energization operation to the low efficiency power generation operation. In this way, the field current of the generator 3 is gradually increased, and electric power is consumed inside the generator 3. As a result, the voltage between the terminals of the first battery 1 is decreased, the potential difference from the voltage between the terminals of the second battery 2 is reduced, and the current consumption in the generator 3 is reduced.

  At time t = T605, the power management unit 7 decreases the voltage between the terminals of the first capacitor 1 to be equal to or lower than the first predetermined threshold voltage T1H, and the voltage between the terminals of the first capacitor 1 and the second capacitor 2. It is determined that the potential difference between the terminals is within the first predetermined voltage range. As a result, the power management unit 7 instructs the first switch 6 to switch from the non-conducting state to the conducting state, and the first switch 6 becomes the conducting state. Therefore, a current flows from the first capacitor 1 to the second capacitor 2, and the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 are equal. The current of the generator 3 outputs a current necessary for maintaining the voltage between the terminals of the first capacitor 1 and the second capacitor 2 and a current supplied to the auxiliary machinery 5 of the vehicle. The power generation torque of the power generator 3 is a torque corresponding to the power generation amount of the power generator 3. The engine output torque is a sum of the power generation torque of the generator 3 and the torque necessary to maintain the engine rotation. The operation command of the generator 3 is switched from the low-efficiency power generation operation to the normal power generation operation after the first switch 6 is turned on, and supplies power to the auxiliary machinery 5 and the second battery 2 of the vehicle. .

  7A and 7B are flowcharts showing the operation of power supply management unit 7 according to Embodiment 2 of the present invention.

  In step S701, it is determined whether or not a failure of the power converter 4 has occurred. The voltage between the terminals of the first battery 1 is not less than the drive lower limit voltage of the power converter 4 and is measured by the power converter output current detection means 10 even though the power converter 4 can be driven. When the output current of the power converter 4 is equal to or lower than the lowest current during normal driving, it is determined that there is a failure, and the process proceeds to step S702. On the other hand, if it is not determined that there is a failure, the process ends.

  In step S702, a power generation prohibition operation is commanded to the generator 3, and the process proceeds to step S703.

  In step S703, the engine controller 14 is instructed to prohibit idling stop, and the process proceeds to step S704.

  In step S704, the operation is held for a predetermined time after the failure is detected, and the process proceeds to step S705.

  In step S <b> 705, it is determined whether the voltage between the terminals of the first battery 1 is lower than the voltage between the terminals of the second battery 2. When the voltage between the terminals of the first capacitor 1 is equal to or lower than the voltage between the terminals of the second capacitor 2, the process proceeds to step S721, while the voltage between the terminals of the first capacitor 1 is equal to that of the second capacitor 2. If it is higher than the terminal voltage, the process proceeds to step S706.

  In step S706, it is determined whether the voltage between the terminals of the first battery 1 is equal to or higher than a second predetermined threshold voltage T2. When the voltage between the terminals of the first capacitor 1 is equal to or higher than the second predetermined threshold voltage T2, the process proceeds to step S707, while the voltage between the terminals of the first capacitor 1 is less than the second predetermined threshold voltage T2. If there is, the process proceeds to step S709.

  In step S707, the power management unit 7 switches the second switch 8 from the non-conductive state to the conductive state, and proceeds to step S708.

  In step S708, it is determined whether or not the voltage detected by the inter-terminal voltage detection means 7a of the first capacitor 1 is equal to the voltage detected by the inter-terminal voltage detection means 7c of the third capacitor 9. When the voltage between the terminals of the first capacitor 1 is equal to the voltage between the terminals of the third capacitor 9, the process proceeds to step S709, while the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the third capacitor 9 is If they are not equal, the process remains in step S708 and the determination is repeated until they are equal.

  In step S709, it is determined whether or not the potential difference between the terminal voltage of the first capacitor 1 and the terminal voltage of the second capacitor 2 is within the first predetermined voltage range. If the voltage between the terminals of the first capacitor 1 is within the first predetermined voltage range, that is, not higher than the first predetermined threshold voltage T1H and not lower than the first predetermined threshold voltage T1L, the process proceeds to step S720. On the other hand, if it is outside the first predetermined voltage range, the process proceeds to step S710.

  In step S710, the power management unit 7 switches the operation mode of the generator 3 to the voltage reduction operation mode, and proceeds to step S711.

  In step S711, it is determined whether or not the engine speed is equal to or higher than a predetermined engine speed N1. If it is greater than or equal to the predetermined engine speed N1, the process proceeds to step S712. If it is less than the predetermined engine speed N1, the process proceeds to step S715.

  In step S712, it is determined whether the temperature of the generator 3 measured by the thermistor 3e is higher than a second predetermined temperature. The second predetermined temperature is set to a value obtained by experiment to determine the maximum temperature at which the generator 3 does not fail when the armature winding 3b is energized. As a result of the determination, if the temperature is equal to or lower than the second predetermined temperature, the process proceeds to step S713. If the temperature is higher than the second predetermined temperature, the process proceeds to step S714.

  In step S713, the power management unit 7 energizes the armature winding 3b. After energizing the armature winding 3b, the process returns to step S709 to continue the processing.

  In step S714, since the temperature of the generator 3 measured by the thermistor 3e is high, all the semiconductor elements are turned OFF to prohibit energization of the armature winding 3b, and the process returns to step S709 to continue the processing.

  In step S715, it is determined whether or not the temperature of the generator 3 is higher than the first predetermined temperature. The first predetermined temperature is set to a value obtained by experiment to determine the maximum temperature at which the generator 3 does not fail while the field winding 3b is energized. If the temperature is equal to or lower than the first predetermined temperature, the process proceeds to step S716. If the temperature is higher than the first predetermined temperature, the process proceeds to step S718.

  In step S716, the power management unit 7 calculates a field current limit value that limits the current flowing through the field winding 3c so as to achieve a low-efficiency power generation operation, and the process proceeds to step S717. The field current limit value is obtained by a look-up table using the engine speed and the voltage between terminals of the generator 3 as arguments. An example of setting the table is shown in FIG. The field currents have a relationship of If3> If2> If1, respectively. In this setting example, in a region where the engine speed is low and the inter-terminal voltage of the generator 3 is high, the limit value increases so as to increase the field current that can flow, the engine speed is high, and the inter-terminal voltage of the generator 3 is increased. In a low region, the limit value becomes small so as to reduce the field current that can flow.

  In step S717, the field current command value is calculated, and the process proceeds to step S719. The calculation of the field current command value is calculated using the following equation.

Field current command value
= MIN (field current command value (previous value) + field current increase, field current limit value)

  However, MIN (A, B) represents a function that returns the minimum value of A and B. The initial value of the field current command value is 0 [A].

  In step S718, the field current command value is set to 0 [A], and the process proceeds to step S719.

  In step S719, the field current command value calculated by the power management unit 7 in step S717 or 0 [A] set in step S718 is commanded to the field current control circuit 3d. The field current control circuit 3d performs control so that the commanded field current is obtained, returns to step S709, and continues the processing.

  In step S720, the power management unit 7 instructs the generator 3 to perform a normal power generation operation, and proceeds to step S723.

  In step S721, the power management unit 7 instructs the generator 3 to perform a normal power generation operation, and the process proceeds to step S722.

  In step S722, it is determined whether or not the potential difference between the terminal voltage of the first capacitor 1 and the terminal voltage of the second capacitor 2 is within a first predetermined voltage range. If the voltage between the terminals of the first capacitor 1 is within the first predetermined voltage range, that is, not higher than the first predetermined threshold voltage T1H and not lower than the first predetermined threshold voltage T1L, the process proceeds to step S723. On the other hand, if the voltage is outside the first predetermined voltage range, the process returns to step S721 to continue the process.

  In step S723, the power management unit 7 instructs the first switch 6 to switch from the non-conductive state to the conductive state, and ends the process.

  In Embodiment 2 of the present invention, as a method of reducing the voltage across the terminals of the first battery 1, the low-efficiency power generation operation performed during the voltage reduction operation mode of the generator 3 described in Embodiment 1 In addition to the two types of armature winding energization operation, the third capacitor 9 connected in parallel with the first capacitor 1 is further connected by turning on the second switch 8 when a predetermined condition is satisfied. A total of three types are defined, with the addition of “preliminary capacitor charging operation” performed in the “preliminary capacitor charging mode” to be in a conductive state. Although each operation has been described above, the standby capacitor charging mode has the following characteristics. Note that the features of the low-efficiency power generation operation and the armature winding energization operation have already been described in the first embodiment, and thus the description thereof will be omitted here and the first embodiment will be referred to.

The standby capacitor operation in the standby capacitor charging mode has the following characteristics.
The electrical resistance between the first capacitor 1 and the third capacitor 9 is small, and when the second switch 8 is turned on, power is rapidly transferred from the first capacitor 1 to the third capacitor 9. As a result, the voltage across the terminals of the first battery 1 can be greatly reduced in a short time.
-Since the voltage stops decreasing at the timing when the voltage between the terminals of the first capacitor 1 and the third capacitor 9 is in an equilibrium state, there is a limit to the voltage that can be decreased, and the voltage is It is determined by the capacities of the capacitor 1 and the third capacitor 9 and their initial voltages.
-Since only the second switch 8 can be controlled, the degree of voltage drop and the amount of flowing current cannot be adjusted.
-It is not connected to the engine dynamically and operates independently of the engine, so the operation is not limited by the rotational speed.
• A large current flows during the mode, but the electrical resistance in the circuit is small and the temperature rise during operation is small.

  As described above, each of the three types of methods for reducing the voltage across the terminals of the first battery 1 has its characteristics. Therefore, it is desirable to select a method according to the state of the vehicle, the engine, and the power system. That is, when the potential difference is large, the standby capacitor charging mode is set, and the potential difference is still large even after the standby capacitor charging mode is performed in the system not including the third capacitor 9 or the system including the third capacitor 9. If an armature winding energization operation is selected and a low-efficiency power generation operation is selected in a region where the potential difference is small and the engine speed is low, an appropriate operation utilizing each characteristic can be obtained.

  As described above, also in the second embodiment, when a failure occurs in the power converter 4 as in the first embodiment, it is provided between the high voltage circuit and the low voltage circuit. Since the first switch 6 is configured to be switched to the conductive state, even when a failure of the power converter 4 occurs, the power generated by the generator 3 can be supplied to the auxiliary machinery 5 of the vehicle. Therefore, it is possible to continue traveling stably without stopping the auxiliary machinery 5 of the vehicle. In addition, since only the first switch 6 is provided, it is possible to reduce the cost and size as compared with the case of dual system. Further, since the first switch 6 is switched to the conductive state after the potential difference between the high voltage circuit and the low voltage circuit falls within the first predetermined voltage, the vehicle is compensated without increasing the voltage of the low voltage circuit. It is possible to prevent burnout beyond the withstand voltage of the machinery 5.

  In the second embodiment, a third battery 9 connected in parallel to the first battery 1 is further provided, and the conduction state of the first battery 3 and the third battery 9 is switched. A second switch 8 that can be used, and when the power management unit 7 detects a failure of the power converter 4, the normal power generation operation for charging the first capacitor 1 to the generator 3 is performed. Instructing to switch to the power generation prohibition operation to prohibit the power generation operation, and when the voltage between the terminals of the first battery 1 is higher than the second predetermined voltage T2 wider than the first predetermined voltage range (that is, the first The difference between the voltage between the terminals of the first capacitor 1 and the voltage between the terminals of the second capacitor 2 is outside the second predetermined voltage range wider than the first predetermined voltage range, and the terminal of the first capacitor 1 When the voltage between the terminals of the second battery 2 is higher) The second switch 8 is turned on, the first capacitor 1 and the third capacitor 9 are turned on, and the third capacitor 9 is charged. An instruction is given to switch to a voltage lowering operation that consumes power inside the machine, and the voltage between the terminals of the first battery 1 is controlled to approach the voltage between the terminals of the second battery 2. As a result, since the electric power stored in the first electric storage device 1 is used for charging the third electric storage device 9, the voltage between the terminals of the first electric storage device 1 can be quickly reduced. In addition to minimizing the time during which power is not supplied, the power stored in the first battery 1 can be effectively used because the place where the power is stored is merely moved. In addition, since the two voltage reduction operation modes described above are restricted by the current flowing to reduce the voltage between the terminals of the first capacitor 1 and the engine speed, the voltage between the terminals of the first capacitor 1 is reduced. Although it cannot be reduced or the voltage drop between the terminals of the first battery 1 is gradual, the terminal of the first battery 1 is configured regardless of the engine speed by being configured as described above. The inter-voltage can be quickly reduced. According to recent market research, at present, the power storage device has a drastic price drop compared to the DC / DC converter, and can be configured at a lower cost than the two DC / DC converters. In addition, since the third capacitor 9 is specialized for the function as a backup at the time of failure, even if the capacity is smaller than that of the first capacitor 1, the third capacitor 9 is effective. If the capacity | capacitance of the 3 electrical storage device 9 is selected appropriately, it can reduce in size rather than dual system of a DC / DC converter.

  In the above description of the second embodiment, it has been described that the voltage drop operation mode includes two types of the armature winding energization operation and the low-efficiency power generation operation. It is good also as a structure including only. In that case, regardless of the engine speed, the power management unit 7 determines that the potential difference between the terminal voltage of the first battery 1 and the voltage between the terminals of the second battery 2 is outside the first predetermined voltage range. In addition, when it is determined that a predetermined condition that the voltage between the terminals of the first battery 1 is higher than the voltage between the terminals of the second battery 2 is included, either one included in the voltage reduction operation mode (That is, the armature winding energization operation or the low-efficiency power generation operation) may be performed.

  In addition, you may make it comprise the generator 3 demonstrated in said Embodiment 1 and Embodiment 2 with a generator motor. In that case, even if the drive function of the generator motor constituting the generator 3 cannot be used when the power converter 4 fails, the first battery 1 can be obtained by using the generator function of the generator motor. The voltage between the terminals can be reduced.

  Moreover, although Embodiment 1 and 2 were demonstrated as mentioned above, when the electrical potential difference between the terminals of the first capacitor 1 and the second capacitor 2 is within the first predetermined voltage, the first capacitor 1 As long as the first switch 6 can be turned on so as to bring the second capacitor 2 into a conductive state, the present invention is not limited to the above-described configuration.

  1 first capacitor, 2 second capacitor, 3 generator, 3a rectifier circuit, 3b armature winding, 3c field winding, 3d field current control circuit, 3e thermistor, 4 power converter, 5 vehicle Auxiliaries, 6 first switch, 7 power management unit, 7a voltage detection means between terminals of first capacitor, 7b voltage detection means between terminals of second capacitor, 7c voltage detection means between terminals of third capacitor , 8 Second switch, 9 Third capacitor, 10 Power converter output current detecting means, 11 Engine speed detecting means, 12 Throttle opening detecting means, 13 Injector, 14 Engine control device, 15 Accelerator opening detecting means .

Claims (11)

A first circuit including a first capacitor, a second circuit including a second capacitor, and power conversion for converting the power of the first capacitor and supplying the converted power to the second capacitor and a vehicle auxiliary device A power management device provided in a vehicle including a storage device and a generator connected to the first capacitor and generating power by external torque to charge the first capacitor,
The first circuit and the second circuit are connected between the first circuit and the second circuit in a non-conducting state in a normal state, and when a switching command is received, A first switch for switching from a non-conductive state to a conductive state;
When a failure of the power converter is detected, the generator is instructed to switch from a normal power generation operation that charges the first battery to a voltage reduction operation that consumes power inside the generator. After the voltage reduction operation, when the difference between the voltage of the first capacitor and the voltage of the second capacitor is within a first predetermined voltage range, the first switch And a power management unit that outputs a switching command. The voltage drop operation is
When the difference between the voltage of the first capacitor and the voltage of the second capacitor is outside the first predetermined voltage range and the voltage of the first capacitor is higher than the voltage of the second capacitor, By controlling the current flowing in the field winding of the generator, the generator is caused to generate power in a state where the power generation efficiency is lower than a predetermined value set in advance, and the first battery The power management apparatus according to claim 1, wherein the power management apparatus is a low-efficiency power generation operation that reduces a voltage. The voltage drop operation is
When the difference between the voltage of the first capacitor and the voltage of the second capacitor is outside the first predetermined voltage range and the voltage of the first capacitor is higher than the voltage of the second capacitor, An armature winding energizing operation in which the field winding of the generator is de-energized and only the armature winding of the generator is energized to reduce the voltage of the first capacitor. The power management device according to claim 1. The voltage drop operation is
When the difference between the voltage of the first capacitor and the voltage of the second capacitor is outside the first predetermined voltage range and the voltage of the first capacitor is higher than the voltage of the second capacitor, By controlling the current flowing in the field winding of the generator, the generator is caused to generate power in a state where the power generation efficiency is lower than a predetermined value set in advance, and the first battery Low-efficiency power generation operation to reduce the voltage,
When the difference between the voltage of the first capacitor and the voltage of the second capacitor is outside the first predetermined voltage range and the voltage of the first capacitor is higher than the voltage of the second capacitor, An armature winding energization operation for deenergizing the field winding of the generator and energizing only the armature winding of the generator to reduce the voltage of the first capacitor;
The power management unit performs the armature winding energization operation when the engine speed is greater than or equal to a predetermined value set in advance for the generator, and the engine speed is less than the predetermined value. The power management apparatus according to claim 1, further comprising: instructing to perform the low-efficiency power generation operation.   5. The power management apparatus according to claim 2, wherein the power management unit stops the low-efficiency power generation operation when a temperature of the generator is equal to or higher than a first predetermined temperature set in advance.   5. The power management according to claim 3, wherein the power management unit stops the armature winding energization operation when the temperature of the generator is equal to or higher than a second predetermined temperature set in advance. 6. apparatus. When the power management unit detects a failure of the power converter, the power management unit outputs a command for prohibiting a normal power generation operation for charging the first capacitor to the generator, and after outputting the command, After detecting a failure of the power converter by instructing to switch to a voltage lowering operation that consumes electric power inside the generator after a predetermined time has elapsed, the first switch is changed from a non-conductive state to a conductive state. The power management device according to any one of claims 1 to 6, wherein a change in torque generated or absorbed by the generator is controlled to be equal to or less than a predetermined value until switching. A third capacitor connected in parallel with the first capacitor;
Connected between the first capacitor and the third capacitor, puts the first capacitor and the third capacitor into a non-conductive state, and receives a second switching command from the power management unit. And a second switch for switching from the non-conducting state to the conducting state.
When the power management unit detects a failure of the power converter, the power generation prohibiting operation prohibits the normal power generation operation from the normal power generation operation for charging the first capacitor to the generator. The difference between the voltage of the first capacitor and the voltage of the second capacitor is outside a second predetermined voltage range wider than the first predetermined voltage range, and the first When the voltage of one capacitor is higher than the voltage of the second capacitor, the second switch command is output to the second switch, whereby the first capacitor and the third capacitor are output. And instructing the power generator to switch from the power generation prohibiting operation to a voltage lowering operation that consumes power inside the power generator, after charging the third capacitor in a conductive state, The voltage of the first capacitor is Claims 1 and performs control to close the voltage of the storage battery to 7 power management device according to any one of.   The power management apparatus according to claim 1, wherein the generator is configured by a generator motor. A first circuit including a first capacitor, a second circuit including a second capacitor, and power conversion for converting the power of the first capacitor and supplying the converted power to the second capacitor and a vehicle auxiliary device And a power management method implemented in a vehicle including a generator and a generator connected to the first capacitor and generating power by external torque to charge the first capacitor,
Turning off a first switch connected between the first circuit and the second circuit;
Detecting the failure when the power converter fails; and
Controlling the generator to switch to a voltage drop operation that consumes power within the generator when the failure is detected;
After the voltage lowering operation, when the difference between the voltage of the first capacitor and the voltage of the second capacitor falls within the first predetermined voltage range, the first switch is turned on from the non-conductive state. And a step of switching to a state. A first circuit including a first capacitor;
A second circuit including a second capacitor;
A power converter that converts the power of the first capacitor and supplies it to the second capacitor and an auxiliary device of the vehicle;
A generator connected to the first capacitor and generating power by external torque to charge the first capacitor;
The first circuit and the second circuit are connected between the first circuit and the second circuit in a non-conducting state in a normal state, and when a switching command is received, A first switch for switching from a non-conductive state to a conductive state;
When a failure of the power converter is detected, the generator is instructed to switch from a normal power generation operation that charges the first battery to a voltage reduction operation that consumes power inside the generator. After the voltage reduction operation, when the difference between the voltage of the first capacitor and the voltage of the second capacitor is within a first predetermined voltage range, the first switch A power management system comprising: a power management unit that outputs a switching command.

Images