JP2016153277A - Vehicle controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle controller capable of securing traveling performance while improving protection of a battery and a connection device.SOLUTION: A vehicle driving motor 1 and a motor 2 driven by an engine 11 are arranged in a high-voltage circuit 6, a vehicle driving battery 3 is disposed in an intermediate-voltage circuit 7 of a potential lower than that of the high-voltage circuit 6, and a transformer 4 is provided between the high-voltage circuit 6 and the intermediate-voltage circuit 7. A heater 16 operated by power from the high-voltage circuit 6 to increase the temperature of the battery 3 is provided to detect the temperature of the heater 16 by a temperature sensor 19. A heater control unit 9E is provided to calculate the maximum output Pof the heater 16 based on the temperature T detected by the temperature sensor 19, and control the heater 16 by using a value obtained by multiplying the maximum output Pby a predetermined ratio R as a target output P.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle control device that raises the temperature of a battery for driving a vehicle using electric power of a high-voltage circuit in which an electric motor for driving the vehicle and a generator for supplying power to the electric motor are arranged.

The performance of the battery for driving the vehicle mounted on the vehicle varies depending on the temperature of the usage environment. For example, the charge / discharge power when the battery temperature is low is lower than that at room temperature. Therefore, a temperature sensor and an electric heater are provided in the battery case, and the battery temperature is managed so as to be within a predetermined range.
On the other hand, in a hybrid vehicle that drives an electric motor (vehicle drive motor) using both the electric power generated by an engine-driven generator and the stored electric power of the battery, the generated electric power is assigned to the electric motor driving electric power when the battery temperature is low. be able to. In view of this, there has been proposed a technique for raising the temperature of the battery while running the vehicle using the power generated by the generator.
For example, it is conceivable to supply the generated power to an electric motor and an electric heater to drive the vehicle while raising the temperature of the battery. Alternatively, it is conceivable to increase the temperature of the battery by using Joule heat generated with charging and discharging of the battery (see Patent Document 1). By using these methods, it is possible to raise the temperature of the battery while maintaining the traveling performance of the vehicle.

JP 2012-214142 A

However, for example, in a cryogenic environment where the battery is significantly below freezing point, the charge / discharge characteristics of the battery are greatly reduced, and deterioration due to a charging operation is particularly likely to proceed. Therefore, if charging / discharging is repeated in a state in which the battery is extremely cold, the battery life may be shortened. Further, it is conceivable that the battery is charged by regenerative electric power generated by the electric motor while the vehicle is running, even if power generation by the electric generator is stopped. Therefore, it is desirable to control the flow of power so that the battery is not charged while the vehicle is running.
On the other hand, if a state in which charging / discharging cannot be performed is formed by electrically disconnecting a low temperature battery from an electric circuit, such deterioration of the battery is prevented. However, in this case, since the battery is disconnected from the electric circuit, the buffer effect of the battery (the effect of suppressing power fluctuation) cannot be used, and the traveling performance of the vehicle can be reduced. For example, if the target output of the motor exceeds the power generation output of the generator during vehicle acceleration, the acceleration decreases due to power shortage. Similarly, if the target output of the electric motor falls below the power generation output of the generator during deceleration of the vehicle, the power becomes excessive and the deceleration is reduced.

It is also conceivable that a heater is connected to a high voltage circuit in which an electric motor and a generator are arranged, and that this heater bears a power buffer function. In other words, this is a method of absorbing power fluctuations in the high voltage circuit by increasing or decreasing the power consumption in the heater. In this case, if the heater is built in the battery, the buffer effect can be utilized while the temperature of the battery is raised quickly.
However, the power consumption of the heater can vary depending on the temperature of the heater itself. In particular, when a PTC heater having a characteristic that the resistance increases as the temperature rises, the power consumption (that is, the heater output) of the heater decreases as the heater temperature rises and can be absorbed by the heater. The power fluctuation range becomes smaller. As a result, the electric motor, the generator, the converter, and the inverters on the electric circuit are directly affected by the load fluctuation, which may cause a malfunction.

  One of the objects of the present invention was devised in view of the above-described problems, and is a vehicle control device that ensures the traveling performance of the vehicle while improving the protection of the battery and the connected devices provided on the circuit. Is to provide. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

(1) In the vehicle control device disclosed herein, an electric motor for driving a vehicle and a generator driven by an engine are arranged in a high voltage circuit, and the battery for driving the vehicle has a lower potential than the high voltage circuit. The vehicle control device is arranged in an intermediate voltage circuit and a transformer is interposed between the high voltage circuit and the intermediate voltage circuit.
The present control device includes a heater that operates with electric power of the high-voltage circuit and raises the temperature of the battery, and a temperature sensor that detects the temperature of the heater. The control device calculates a maximum output of the heater based on the temperature detected by the temperature sensor, and controls the heater using a value obtained by multiplying the maximum output by a predetermined ratio as a target output. A part.
The transformer performs step-up and step-down between the high voltage circuit and the medium voltage circuit, and is also called an up / down converter (up / down converter).
Further, the heater preferably has a characteristic [PTC (Positive Temperature Coefficient) characteristic] in which the resistance increases as the temperature rises.

(2) It is preferable that the heater control unit calculates the maximum output as a smaller value as the temperature of the heater is higher.
(3) It is preferable that the heater control unit sets the predetermined ratio based on a fluctuation characteristic relating to an output difference between the generated power of the generator and the consumed power of the electric motor.
For example, when the output difference is likely to increase in the positive direction, it is preferable to set the predetermined ratio smaller. On the other hand, when the output difference is likely to increase in the negative direction, it is preferable to set the predetermined ratio larger.
(4) It is preferable that the heater control unit sets the predetermined ratio to 0.5. In this case, the target output is half of the maximum output.

(5) It is preferable to include a modulator that is interposed on a circuit that connects the heater and the high voltage circuit, and that modulates a direct current of the high voltage circuit into a pulse signal and outputs the pulse signal to the heater. Specific examples of the modulator include a PWM controller that controls output by a PWM (Pulse Width Modulation) method, a PAM controller that controls output by a PAM (Pulse Amplitude Modulation) method, and an output control by a PPM (Pulse Position Modulation) method. A PPM controller or the like can be used.
(6) It is preferable that the heater control unit controls the modulator using a total value of an output difference between the generated power of the generator and the power consumption of the motor and the target output.

  According to the disclosed vehicle control device, the electric motor and the heater can be driven by the electric power generated by the generator while preventing the battery from being charged, and the heater can be used as a power buffer of the high voltage circuit. it can. Furthermore, by calculating the maximum output based on the heater temperature and multiplying the maximum output by a predetermined ratio to make the target output, the power consumption of the heater is controlled taking into account the total available buffer capacity at that time The buffer capacity can be used effectively. Therefore, it is possible to ensure the traveling performance of the vehicle while improving the protection of the battery and the connected device.

It is a figure which shows typically the apparatus structure of embodiment. (A), (B) is a schematic diagram which shows the internal structure of a battery. It is a graph which shows the relationship between the temperature of a heater, and an output. It is a flowchart for demonstrating the procedure of the control at the time of low temperature. It is a flowchart for demonstrating the control procedure of a heater output. It is a flowchart for demonstrating the control procedure of a heater output. It is a flowchart for demonstrating the procedure of heater cooling control. (A)-(E) are the graphs for demonstrating the content of heater cooling control.

  A vehicle control apparatus as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment, and can be selected or combined as necessary.

[1. vehicle]
The control apparatus of this embodiment is applied to the vehicle 10 shown in FIG. This vehicle 10 is a series hybrid vehicle, and a motor 1 (electric motor), a generator 2 (generator) and an engine 11 are mounted on a power train. The engine 11 is a prime mover that drives the generator 2 to generate electric power, and is controlled so as to continue operation in a rotational speed region where engine efficiency is high as necessary. The generated power generated by the generator 2 can be directly supplied to the motor 1 via the high voltage circuit 6, and to the driving battery 3 (battery) via the up / down converter 4 (transformer). It is also rechargeable.

  The motor 1 is an electric motor that drives wheels using charging power stored in the battery 3 and generated power generated by the generator 2. The battery 3 is connected to a medium voltage circuit 7 having a maximum voltage lower than that of the high voltage circuit 6. In the battery case of the battery 3, a battery pack 20 in which a plurality of battery cells are unitized and a battery temperature sensor 15 for detecting the temperature (battery temperature) are provided. Information on the battery temperature acquired here is transmitted to the electronic control unit 9 described later.

  The high voltage circuit 6 is provided with a heater 16 and a PWM controller 17 (modulator). The heater 16 is a heater with a built-in resistor for raising the temperature of the battery 3 and is built in the battery case. The heater 16 of this embodiment is a PTC heater having a characteristic [PTC (Positive Temperature Coefficient) characteristic] in which the resistance increases as the temperature rises. A heater temperature sensor 19 that detects the temperature T of the heater 16 is provided in the vicinity of the heating element of the heater 16. Information about the heater temperature T acquired here is transmitted to the electronic control unit 9.

  The PWM controller 17 modulates the direct current of the high voltage circuit 6 into a pulse signal and outputs it to the heater 16. Here, the pulse width of the pulse signal modulated by the PWM (Pulse Width Modulation) method is adjusted, and the current (power) output to the heater 16 side is freely controlled. That is, the power for operating the heater 16 is covered by the power in the high voltage circuit 6. The operating state of the PWM controller 17 (the output of the heater 16) is controlled by the electronic control unit 9.

  As shown in FIG. 1, a fan 18, a heat exchanger 21, and a valve 22 are provided in the battery case of the battery 3, and an outside fan 23 that cools the outer surface of the battery case is provided outside the battery 3. It is done. The fan 18 is a blower that supplies cooling air toward the heating element of the heater 16, and is disposed in the vicinity of the heater 16. The heat exchanger 21 is a cooling device for cooling the air in the battery case (cooling air from the heater 16). The valve 22 is a switching valve that controls the flow of cooling air in the battery case.

  Inside the battery 3, two passages are provided as passages through which the cooling air circulates. The first passage is a passage through which the cooling air is circulated between the battery pack 20 and the heater 16, and the second passage is a passage through which the cooling air is circulated so as to bypass the battery pack 20. Here, the former is called the first passage 31 and the latter is called the second passage 32. The second passage 32 is formed in a shape that branches on the upstream side of the battery pack 20 in the first passage 31 and merges on the downstream side of the battery pack 20. The valve 22 is disposed at a branch point between the first passage 31 and the second passage 32 and has a function of simultaneously adjusting the flow rate of cooling air flowing to the first passage 31 and the flow rate of cooling air flowing to the second passage 32. .

  As shown by a black arrow in FIG. 2A, in a state where the valve 22 closes the second passage 32 side, a flow path in which cooling air circulates between the battery pack 20 and the heater 16 is formed. On the other hand, as indicated by a white arrow in FIG. 2B, in a state where the valve 22 closes the first passage 31 side, a flow path in which the cooling air bypasses the battery pack 20 is formed. The opening degree of the valve 22 is continuously adjusted. Thereby, the ratio of the flow rate on the first passage 31 side and the flow rate on the second passage 32 side can be arbitrarily controlled. For example, the flow rate on the first passage 31 side can be adjusted from 0% to 100%, and the flow rate on the second passage 32 side is adjusted from 100% to 0% to correspond to this. . The heat exchanger 21 is interposed on the second passage 32.

  The transformation state between the medium voltage circuit 7 and the high voltage circuit 6 is controlled in both directions by the up / down converter 4. Further, on the intermediate voltage circuit 7, a downverter 5 (step-down device) that steps down the electric power of the intermediate voltage circuit 7 and supplies it to various electrical components (auxiliaries) on the low voltage circuit 8 is interposed. . As the various electrical components described above, FIG. 1 illustrates an auxiliary battery 12, an air conditioner 13, an electronic control device 9, and other in-vehicle control devices 14. A vehicle speed sensor 24 that detects the vehicle speed V is provided at an arbitrary position of the vehicle 10. Information on the vehicle speed V detected here is also transmitted to the electronic control unit 9.

  Regarding the high voltage circuit 6, the medium voltage circuit 7, and the low voltage circuit 8, the maximum voltage in each circuit is the highest in the high voltage circuit 6 and the lowest in the low voltage circuit 8. The voltage of the high voltage circuit 6 varies according to the driving voltage of the motor 1 and the generated voltage of the generator 2, and can rise up to, for example, about 600 [V] at the maximum. Further, the voltage of the intermediate voltage circuit 7 varies according to the charge / discharge voltage of the battery 3, for example, within a range of 200 to 300 [V]. On the other hand, the voltage of the low voltage circuit 8 is a voltage related to driving of various electrical components and is, for example, about 11 to 12 [V].

  In the present embodiment, when the battery temperature is lower than a predetermined temperature, low temperature control is performed in which the battery 3 is heated while preventing the battery 3 from being charged and the traveling state of the vehicle 10 is maintained. The charge / discharge state of the battery 3 is determined by the magnitude relationship between the battery voltage and the voltage of the intermediate voltage circuit 7. For example, when the up / down barter 4 supplies power higher than the battery voltage from the high voltage circuit 6 to the medium voltage circuit 7 when the downverter 5 is stopped, the power is charged in the battery 3. On the other hand, if the voltage generated by the up / down converter 4 is lower than the battery voltage, the battery 3 is not charged.

  Further, when the downverter 5 is in operation and various electrical components on the low voltage circuit 8 act as a load, the power on the medium voltage circuit 7 side is consumed on the low voltage circuit 8 side. At this time, if the battery 3 is being charged, the sum of the power consumption of the low voltage circuit 8 and the charging power of the battery 3 corresponds to the power input from the high voltage circuit 6 side. On the other hand, if the battery 3 is being discharged, the power consumption of the low voltage circuit 8 corresponds to the sum of the power input from the high voltage circuit 6 side and the discharge power of the battery 3.

  Therefore, by setting the power input from the high voltage circuit 6 side to the same value with respect to the power consumption in the low voltage circuit 8, it is possible to maintain the state in which the battery 3 is neither charged nor discharged. . Based on such characteristics, the electronic control unit 9 performs increase / decrease control of the power generated by the generator 2 and the power supplied from the up / down converter 4 to the medium voltage circuit 7 in the low temperature control. Thus, the power supply state in the power train of the vehicle 10 is controlled so that the traveling state of the vehicle 10 is maintained and the battery 3 is not charged.

  In the present embodiment, the heater 16 is provided with a power buffer function, and the heater 16 absorbs excess or deficiency of power in the high voltage circuit 6. That is, the power consumed by the heater 16 (heater output) is controlled based on the output difference between the actual generated power actually generated by the generator 2 and the actual motor consumed power actually consumed by the motor 1. . However, since the electric power consumed by the heater 16 varies according to the temperature of the heater 16 itself, heater cooling control for suppressing overheating of the heater 16 is also performed.

The maximum output P _MAX of the heater 16 decreases as the heater temperature T rises, as shown by a thick solid line in FIG. This is because the resistance increases as the heater temperature T increases, and the current flowing through the heating element of the heater 16 decreases when the same voltage is applied. Here, if the target output _PTGT of the heater 16 is indicated by a thin solid line in FIG. 3, the vertical distance between the horizontal axis and the thin solid line corresponds to an output adjustment allowance that can be absorbed by reducing the heater output. The vertical distance between the thin solid line and the thick solid line corresponds to an output adjustment allowance that can be absorbed by increasing the heater output. Therefore, by continuing to operate the heater 16 in a state where the heater temperature T is lower, it is possible to increase the width of the output adjustment allowance. A heater cooling control, the heater temperature T is clamped to the range of the less than a predetermined temperature T _1, the heater 16 is cooled. The first predetermined temperature T ₁ is a temperature at which the heater output has such a magnitude that the output difference between the actual generated power of the generator 2 and the actual motor power consumption of the motor 1 can be offset.

[2. Electronic control unit]
The electronic control device 9 (control device) is a computer that comprehensively controls various devices in the power train, and is, for example, an LSI device or an embedded electronic device in which a microprocessor, ROM, RAM, and the like are integrated. In this embodiment, low temperature control and heater cooling control will be described. The main control targets in the low temperature control are the motor 1, the generator 2, the engine 11, the up / down barter 4, the downverter 5, and the PWM controller 17, and the respective operating states are obtained by the battery temperature sensor 15. It is controlled according to temperature.

  The low temperature control start condition is that the battery temperature is lower than a predetermined temperature. When the battery temperature is equal to or higher than the predetermined temperature, the normal control for running the vehicle 10 is performed while using the charging power of the battery 3 and the generated power of the generator 2 together, and the heater 16 and the PWM controller 17 are inactive. Is done. On the other hand, in the low temperature control, the vehicle 10 is caused to travel while operating various electrical components on the low voltage circuit 8 using the power generated by the generator 2. In addition to this, control is performed to operate the heater 16 and the PWM controller 17 by utilizing the output difference between the actual motor power consumption actually consumed by the motor 1 and the actual power generation actually generated by the generator 2. Is done. During the execution of the low temperature control, the state in which the battery 3 is not disconnected from the intermediate voltage circuit 7 is maintained in consideration of the buffer effect of the battery 3.

  The electronic control unit 9 includes, as functional elements for performing control at low temperature, a motor control unit 9A, a generator control unit 9B, a transformer control unit 9C, a step-down controller 9D, a heater control unit 9E, and cooling air control. A portion 9F is provided. These elements may be realized by an electronic circuit (hardware), or may be programmed as software, or some of these functions may be provided as hardware, and other parts may be software. It may be what you did.

  The motor control unit 9A has a function of controlling the operating state of the motor 1 so that the power consumed by the motor 1 (power consumption, target motor output) has a magnitude corresponding to the driver's required output. The magnitude of the motor output is calculated and set based on, for example, the accelerator pedal depression amount, the vehicle speed V, the road surface gradient, the outside air temperature, the outside air pressure, and the like. The motor control unit 9 </ b> A has a function of calculating actual motor power consumption actually consumed by the motor 1. The actual motor power consumption is calculated based on the required output calculated in the previous calculation cycle, the actual rotation speed of the motor 1, the actual torque, and the like. Various known methods can be applied to the calculation and setting methods of the required output and actual motor power consumption.

The generator control unit 9B has a function of increasing or decreasing the generated power by controlling the operating states of the generator 2 and the engine 11. The magnitude of the generated power (generator output) of the generator 2 under low temperature control is at least the sum of the power consumption of the motor 1 and the output power supplied to the medium voltage circuit 7 side by the up / down barter 4. The value of In this embodiment, the sum of the power consumption of the motor 1 and the up / down barter output is set as the magnitude of the generated power. As a result, the motor 1 under low temperature control is driven to rotate using only the power generated by the generator 2, thereby preventing the battery 3 from being taken out.
Further, the generator control unit 9B has a function of calculating actual generated power actually generated by the generator 2. The actual generated power is calculated based on the generated power calculated in the previous calculation cycle, the actual rotational speed and actual torque of the generator 2, the actual rotational speed and actual torque of the engine 11, and the like. Various known methods can be applied to the calculation method of the generated power and the actual generated power.

  The transformer control unit 9C controls the operating state of the up / down barter 4 to increase the output power (up / down barter output, transformer output) supplied from the high voltage circuit 6 side to the medium voltage circuit 7 side. Has a function to increase or decrease the thickness. The magnitude of the output power of the up / down barter 4 under low temperature control is basically the same value as the output power supplied by the downverter 5 to the low voltage circuit 8 side. That is, the magnitude of the output power of the up / down barter 4 is controlled so that the power consumed on the low voltage circuit 8 side is supplied to the intermediate voltage circuit 7 under low temperature control. As a result, the battery 3 connected to the intermediate voltage circuit 7 is not charged or discharged, and the buffer effect is obtained.

  In addition, the transformer control unit 9C has a function of taking out insufficient power from the battery 3 when the actual generated power is lower than the actual motor power consumption under low temperature control. The power shortage can be obtained by subtracting the actual generated power from the actual motor power consumption. Further, the power obtained by subtracting the insufficient power from the downverter output is used as the up / downverter output, so that the insufficient power is taken out from the battery 3. In this way, by controlling the magnitude of the output power of the up / down barter 4 so that the power slightly lower than the power consumed on the low voltage circuit 8 side is supplied to the medium voltage circuit 7, the battery 3 is controlled. Becomes a minute discharge state. Even when the actual generated power is lower than the actual motor power consumption, when the shortage of power can be covered in the high voltage circuit 6 (for example, when the heat generated by the heater 16 is large until just before it). The battery 3 does not need to be discharged, and the output power of the up / down barter 4 may be matched with the output power of the downverter 5.

  The step-down controller 9D is configured such that the output power (downverter output, step-down output) supplied from the medium voltage circuit 7 side to the low voltage circuit 8 side corresponds to the required output of various electrical components. In addition, it has a function of controlling the operating state of the downverter 5. The required output of each electrical component is calculated and set based on the type of electrical component that is operating at that time, the operating state of each electrical component, and the like. Various known methods can be applied to the calculation and setting method of the required output.

  The heater control unit 9E has a function of controlling power supplied to the heater 16 side from the high voltage circuit 6 via the PWM controller 17 (ie, heat generated by the heater 16) under low temperature control. Here, the power consumed by the heater 16 is calculated as “heat generation power” based on the output difference between the actual generated power actually generated by the generator 2 and the actual motor consumed power actually consumed by the motor 1. Is done. Two calculation methods will be described as the calculation method of the generated power based on the output difference.

  In the first method, power generated by subtracting actual motor power consumption from actual generated power is used as heat generation power. This method is easy to calculate and can simplify the control configuration. However, when the actual power generation and the actual motor power consumption match, the heater 16 is not energized. Further, when the actual generated power becomes less than the actual motor power consumption, the power of the high voltage circuit 6 is insufficient, and the insufficient power is taken out from the battery 3.

  In the second method, the predetermined reference power is always consumed by the heater 16 during the low temperature control, and the sum of the power obtained by subtracting the generated power from the actual motor power consumption and the reference power is used as the heat generated by the heater 16. It is calculated as electric power. That is, the energization amount of the heater 16 is set in advance to cover the fluctuation range of the output difference between the actual motor power consumption and the generated power. In this case, when the actual motor power consumption of the motor 1 is relatively small with respect to the actual generated power of the generator 2, the heat generation power of the heater 16 may be increased as the surplus output difference increases. On the contrary, when the actual motor power consumption of the motor 1 is relatively large with respect to the actual generated power of the generator 2, the heat generation power of the heater 16 may be reduced as the insufficient output difference increases.

  In the second method, when the heat generated by the heater 16 is less than zero, the insufficient power may be supplemented by the power taken out from the battery 3. That is, when the power consumption of the motor 1 exceeds the power generated by the generator 2, the battery 3 may be charged with a shortage of power. When the battery temperature is low, it is not desirable to charge even with a small amount of power, but with respect to discharging, a small amount of power is acceptable. Using such battery characteristics, the battery 3 may be charged only with electric power for eliminating voltage fluctuations in the high voltage circuit.

The heater control unit 9E of the present embodiment controls the output of the heater 16 based on the second method. That is, the maximum output P _MAX of the heater 16 is calculated based on the heater temperature T detected by the heater temperature sensor 19, and the target output P _TGT of the heater 16 is calculated by multiplying the maximum output P _MAX by a predetermined ratio R. To do. This target output P _TGT becomes the above-mentioned “predetermined reference power”, and the information is transmitted to the PWM controller 17. Information on the output difference between the actual motor power consumption and the generated power is also transmitted to the PWM controller 17. In the PWM controller 17, the pulse width of the pulse signal is adjusted based on the total value of the target output P _TGT and the output difference, and the output fluctuation is absorbed and canceled.

The maximum output _PMAX is calculated as a smaller value as the heater temperature T is higher so as to match the temperature characteristics of the PTC heater as shown in FIG. The value of the ratio R multiplied by the maximum output P _MAX can be arbitrarily set. For example, when it is desired to set the target output P _TGT to a half value (median value) of the maximum output P _MAX , the ratio R may be set to 0.5. Thereby, even when the power is excessive or insufficient in the high voltage circuit 6, the same output adjustment allowance can be secured and the capacity of the heater 16 can be effectively utilized. Further, when there is a bias in excess or deficiency of power in the high voltage circuit 6, a ratio R of a value suitable for the bias may be set.

Here, a method for setting the ratio R will be described in detail.
When the actual motor power consumption of the motor 1 increases during the acceleration of the vehicle 10 and the actual power generation power of the generator 2 increases later, the power corresponding to the output difference between the actual motor power consumption and the actual power generation is a high voltage. The circuit 6 is insufficient. Similarly, when the vehicle 10 is decelerated, the power corresponding to the output difference between the actual motor power consumption and the actual generated power becomes excessive in the high voltage circuit 6.
On the other hand, when the change rate of the actual motor power consumption is smaller than the change rate of the actual generated power, the insufficient power during acceleration is relatively small, and the excessive power during deceleration is relatively large. On the contrary, when the change speed of the actual generated power is smaller than the change speed of the actual motor power consumption, the insufficient power at the time of acceleration becomes relatively large, and the excessive power at the time of deceleration becomes relatively small. That is, the amount of excess or deficiency of power varies depending on the characteristics of the motor 1 and the generator 2.

In consideration of the fluctuation characteristics of the output difference as described above, when the power shortage during acceleration is relatively large (that is, when the output difference of the actual generated power with respect to the actual motor power consumption tends to increase in the negative direction), What is necessary is just to set the value of the ratio R large. As a result, the graph of the target output P _TGT in FIG. 3 moves upward, and the output adjustment allowance (a decrease in the heater output) for compensating for the insufficient power increases.
On the other hand, when the excessive power during deceleration is relatively large (that is, when the output difference between the actual generated power and the actual motor power consumption tends to increase in the positive direction), the value of the ratio R may be set small. . As a result, the graph of the target output P _TGT in FIG. 3 moves downward, and the output adjustment allowance (the increase in the heater output) for offsetting excess power increases.
Thus, by setting the ratio of the target output P _TGT to the maximum output P _MAX according to the fluctuation characteristics of the output difference between the motor 1 and the generator 2, the increase and decrease of the output adjustment allowance are optimized. Therefore, the capacity of the heater 16 can be effectively utilized regardless of whether the acceleration or deceleration is performed.

The cooling air controller 9F performs heater cooling control when the heater temperature T becomes high under low temperature control. In the heater cooling control, the heating element is cooled to reduce the resistance of the heater 16. As a means for cooling the heater 16, a fan 18, a heat exchanger 21, a valve 22, an outside fan 23 and the like are used. Conditions for starting the heater cooling control is a possible heater temperature T is first predetermined temperature above T _1, the termination condition is a possible heater temperature T is lower reference temperature T ₀ or less than the first predetermined temperature The

In the present embodiment, a first predetermined temperature T ₁ , a second predetermined temperature T ₂ , and a third predetermined temperature T ₃ are set as control threshold values. The magnitude relation of the threshold is T ₁ ≦ T ₂ ≦ T ₃ . Fan 18, the heater temperature T is driven when the first predetermined temperature above T _1. Further, opening of the valve 22 is adjusted so as to open the second passage 32 side when the heater temperature T of the second predetermined temperature T ₂ or higher, the heat exchanger 21 is the heater temperature T a third predetermined temperature T ₃ It is driven in the above case. As described above, the higher the heater temperature T is, the higher the cooling degree of the heater 16 is increased stepwise, so that the cooling performance of the heater 16 is improved and the power buffer of the heater 16 is easily secured. If the first predetermined temperature T ₁ , the second predetermined temperature T ₂ , and the third predetermined temperature T ₃ are set to the same value, all of the fan 18, the heat exchanger 21, and the valve 22 when the heater cooling control is started. And the time until the heater 16 is cooled can be shortened.

Further, while the vehicle 10 is traveling, the battery 3 is easily cooled by the traveling wind, whereas when the vehicle 10 is stopped, the cooling effect by the outside air is reduced. Therefore, when the vehicle speed V is less than the predetermined vehicle speed V ₁ was, the outside fan 23 is operated to cool the outer surface of the battery case. Thereby, the whole battery 3 is cooled, and the temperature of the cooling air supplied to the heater 16 is likely to be lowered, so that the cooling performance of the heater 16 is improved.

[3. flowchart]
FIG. 4 is a flowchart illustrating the procedure of the low temperature control. The flow in FIG. 4 is a flow for calculating a target output of various connected devices and performing control. This flow is repeatedly performed, for example, when the main power supply of the vehicle 10 is on. It is assumed that the engine 11 is in a started state. First, the motor controller 9A calculates a target motor output (actual motor power consumption) (step A1), and the step-down controller 9D calculates required outputs of various electrical components as downverter outputs (step A1). A2).

  When the battery temperature is lower than the predetermined temperature (step A3), the transformer controller 9C calculates an output having the same value as the downverter output as the up / downverter output (step A4). Then, in the generator control unit 9B, an added value of the motor output and the up / down barter output is calculated as generated power (step A5), and thereafter, the motor 1, the generator 2, the up / down barter 4, the down barter 5, etc. The operation of various connected devices is controlled (step A6). On the other hand, if the battery temperature is equal to or higher than the predetermined temperature, normal control is performed (step A7). A known technique can be applied to the specific contents of the normal control, and a description thereof will be omitted.

  FIG. 5 is a flow when the heater 16 is controlled using the first method, and is repeatedly executed in parallel with the flow of FIG. 4. First, the actual motor power consumption of the motor 1 is calculated by the motor controller 9A (step B1), and the actual generated power of the generator 2 is calculated by the generator controller 9B (step B2). When the actual power generation is greater than or equal to the actual motor power consumption (step B3), the heater control unit 9E calculates the power obtained by subtracting the actual motor power consumption from the actual power generation as the heat generated by the heater 16 (heater power consumption). (Step B4). Then, the pulse width of the pulse signal output from the PWM controller 17 is controlled so that the generated heat power is consumed by the heater 16 (step B5).

  Further, when the actual power generation is less than the actual motor power consumption, the heat generated by the heater 16 becomes zero or less, so that the PWM controller 17 is deactivated. On the other hand, in the transformer control unit 9C, the power obtained by subtracting the actual generated power from the actual motor power consumption is calculated as the insufficient power (step B6). Then, the output obtained by subtracting the insufficient power from the downverter output is calculated as the up / downverter output so that the insufficient power is output from the battery 3, and the up / downverter 4 is controlled (step B7). As a result, the insufficient power is taken out from the battery 3 and used to drive the motor 1 of the high voltage circuit 6 and various accessories of the low voltage circuit 8.

  FIG. 6 is a flow when the heater 16 is controlled using the second method, and is repeatedly executed in parallel with the flow of FIG. 4. First, the actual motor power consumption of the motor 1 is calculated by the motor controller 9A (step C1), and the actual generated power of the generator 2 is calculated by the generator controller 9B (step C2). On the other hand, the heater controller 9E calculates the reference power of the heater 16 (step C3). The value of the reference power may be a preset fixed value or a variable value set according to the traveling state of the vehicle 10 or the battery temperature.

When the added value of the actual generated power and the reference power is greater than or equal to the actual motor power consumption (step C4), the heater controller 9E generates the heater 16 by subtracting the actual motor power consumption from the added value of the actual generated power and the reference power. The generated heat power (heater power consumption, actual output P _HEAT ) is calculated (step C5). That is, the actual output of the heater 16 is set based on a total value obtained by adding the target output to the output difference between the actual generated power and the actual motor power consumption. Then, the pulse width of the pulse signal output from the PWM controller 17 is controlled so that this heat generation power (actual output P _HEAT ) is consumed by the heater 16 (step C6). Thereby, the electric power actually consumed by the heater 16 varies according to the output difference between the actual generated power and the actual motor power consumption. Further, even if the actual power generation is insufficient, the reference power is reduced and the motor 1 is driven accordingly, so that the power balance in the high voltage circuit 6 is balanced.

  When the added value of the actual generated power and the reference power is less than the actual motor power consumption, since the heat generated by the heater 16 is zero or less, the PWM controller 17 is deactivated. Further, in the transformer control unit 9C, the power obtained by subtracting the actual generated power and the reference power from the actual motor power consumption is calculated as insufficient power (step C7). Then, the output obtained by subtracting the insufficient power from the downverter output is calculated as the up / downverter output so that the insufficient power is output from the battery 3, and the up / downverter 4 is controlled (step C8). As a result, the insufficient power is taken out from the battery 3 and used to drive the motor 1 of the high voltage circuit 6 and various accessories of the low voltage circuit 8.

  FIG. 7 is a flowchart illustrating the procedure of the heater cooling control performed by the cooling air control unit 9F, and while the low temperature control is being performed, in parallel with the flow as illustrated in FIGS. To be implemented. Note that the flag F in the flow represents the execution state of the heater cooling control. For example, F = 1 when the start condition of the heater cooling control is satisfied, and then F = 0 when the end condition is satisfied.

In the cooling air controller 9F, information on the heater temperature T and the vehicle speed V detected by the heater temperature sensor 19 and the vehicle speed sensor 24 is acquired (step D1). If the heater cooling control is not started (step D2), as the starting condition for the heater cooling control, whether the heater temperature T is first predetermined temperature above T ₁ is determined (step D3). When this condition is satisfied, the flag F is set to F = 1, and the fan 18 is driven (steps D4 to D9). In addition, when heater cooling control has already started, the temperature determination after step D5 is implemented.

That is, if the heater temperature, T is the second predetermined temperature T ₂ or the second passage 32 side (Step D5)) valve 22 is opened (step D9), if the heater temperature, T is the third predetermined temperature T ₃ or more (Step D6), the heat exchanger 21 is driven (step D8). Further, the vehicle speed V is less than the predetermined vehicle speed V _1, outside the fan 23 is driven (step D10~D11). When the heater temperature T decreases through these cooling operations and falls below the reference temperature T ₀ (step D12), the flag F is set to F = 0, and the heater cooling control ends (steps D13 to D14). This flow is repeatedly executed until the condition for ending the heater cooling control is satisfied.

[4. Action]
As shown in FIGS. 8A and 8B, the excess or deficiency of power in the high voltage circuit 6 is due to the magnitude relationship between the actual motor power consumed by the motor 1 and the actual generated power generated by the generator 2. Will be decided accordingly. For example, when the driver depresses the accelerator pedal, if the response of the generator 2 is delayed with respect to the motor 1, the actual generated power becomes smaller than the actual motor power consumption, and the power becomes insufficient. On the other hand, when the driver depresses the accelerator pedal, the actual generated power becomes larger than the actual motor power consumption, resulting in surplus power. Such excess or deficiency of power is absorbed and offset by increasing or decreasing the power consumption in the heater 16. However, the amount of power that can be absorbed by the heater 16 is not necessarily constant. For example, as the energization time is prolonged, the heater temperature T increases, and the maximum output P _MAX of the heater 16 decreases. Therefore, the buffer effect by the heater 16 becomes weaker as the energization time elapses, and it becomes difficult to absorb the excess and deficiency of the output fluctuation shown in FIG.

In contrast, in the present embodiment, the heater temperature T becomes the first predetermined temperature above T ₁ is implemented heater cooling control, as shown in FIG. 8 (C), first from the heater temperature T is a reference temperature T ₀ varying between predetermined temperature T _1. A broken line in FIG. 8C indicates an increase in the heater temperature T when the heater cooling control is not performed. Further, the maximum output P _MAX of the heater 16 correspondingly changes in a predetermined output range P _{0 to} P _{1 as} indicated by a thick solid line in FIG. 8D. Note that a broken line in FIG. 8D indicates a decrease in the maximum output P _MAX when the heater cooling control is not performed. The vertical distance between the broken line and the thick solid line corresponds to the output margin secured by the heater cooling control.

Further, the heater control unit 9E, as shown by the thin solid line in FIG. 8 (D), a value obtained by multiplying a predetermined coefficient to the maximum output P _MAX is calculated as the target output P _TGT. As a result, an output adjustment allowance is ensured whether the output of the heater 16 is to be increased or decreased. That is, in order to absorb the excess and deficiency of the output fluctuation shown in FIG. 8B, the output corresponding to the excess and deficiency (output difference between the actual motor power consumption and the generated power) and the target output P _TGT are added together. The total value may be the actual output P _HEAT of the heater 16. If the output adjustment allowance of the heater 16 is ensured, the actual output _PHEAT will not exceed the maximum output _PMAX and will not fall below zero. Therefore, as shown in FIG. 8E, the power buffer function by the heater 16 is maintained.

[5. effect]
(1) In the electronic control unit 9 described above, the heater 16 that raises the temperature of the battery 3 using the power of the high voltage circuit 6 can function as a power buffer of the high voltage circuit 6. The voltage fluctuation of the high voltage circuit 6 due to the load fluctuation can be suppressed.
Further, the heater controller 9E calculates the maximum output P _MAX of the heater 16 based on the heater temperature T, and sets a value obtained by multiplying the maximum output P _MAX by a predetermined ratio R as the target output P _TGT . Therefore, the power consumption of the heater 16 can be controlled in consideration of the total buffer capacity that can be used at that time (the power buffer capacity of the heater 16 at that time), and the buffer capacity of the heater 16 can be used effectively. Can do. Therefore, the traveling performance of the vehicle 10 can be ensured while improving the protection of the battery 3 and the connected device.
Further, since the battery 3 is not disconnected from the intermediate voltage circuit 7 even during the low temperature control, the buffer effect of the intermediate voltage circuit 7 can be secured, and the up / down converter 4 The protection of the downverter 5 can be improved.

(2) In the heater controller 9E, the maximum output _PMAX is calculated as a smaller value as the heater temperature T is higher. Thereby, the target output P _TGT can be set in accordance with the temperature characteristics of the PTC heater. Therefore, regardless of the heater temperature T, both an increase and a decrease in the output adjustment allowance can be ensured, and the power buffer function can be optimized.
(3) Also, if the ratio R is set based on the fluctuation characteristics related to the output difference between the actual motor power consumption and the actual generated power, the buffer capacity for power shortage and the buffer capacity for excessive power can both be optimized. The buffer capacity of the heater 16 can be used more effectively. For example, if the value of the ratio R is set to a large value, insufficient power during acceleration can be compensated more reliably. Moreover, if the value of the ratio R is set to a small value, excessive power during deceleration can be more reliably offset.

(4) If the ratio R is set to 0.5, it is possible to set the target output P _{TGT in} which the total buffer capacity of the heater 16 is evenly divided. That is, the buffer capacity for power shortage and the buffer capacity for excessive power can be made equal, and a well-balanced power buffer function can be provided without bias.
(5) In the electronic control unit 9 described above, the DC current of the high voltage circuit 6 is modulated into a pulse signal by the PWM controller 17 and supplied to the heater 16. Thereby, the power consumption in the heater 16 can be freely changed, and the power buffer can be easily adjusted. Therefore, it is possible to easily suppress the voltage fluctuation of the high voltage circuit 6.

(6) The heater controller 9E controls the PWM controller 17 based on the total value obtained by adding the target output to the output difference between the actual generated power and the actual motor power consumption, as shown in Step C5 of FIG. The generated heat power (actual output P _HEAT ) of the heater 16 is adjusted. Thereby, excess and deficiency of power in the high voltage circuit 6 can be absorbed and canceled by the heater 16, and voltage fluctuations of the high voltage circuit 6 due to load fluctuations of the motor 1 and the generator 2 can be effectively suppressed. .

[6. Modified example]
In the above-described embodiment, the example in which the current (power) supplied to the heater 16 is controlled by the PWM controller 17 is exemplified, but instead (or in addition), the output is controlled by a PAM (Pulse Amplitude Modulation) method. A PAM controller, a PPM controller that controls output by a PPM (Pulse Position Modulation) method, or the like can be used. Any controller, electronic circuit, semiconductor device, or the like can be used as long as it modulates at least the high voltage power in the high voltage circuit 6 so as to match the resistance value of the heater 16.

  In the above-described heater cooling control, control is performed to switch the operating state (operation / non-operation) of the fan 18 according to the heater temperature T. In addition to such control, the fan 18 is controlled according to the heater temperature T. It is also possible to control the number of rotations. In this case, the cooling efficiency of the heater 16 can be increased by increasing the rotation speed of the fan 18 as the heater temperature T is higher. Similarly, the opening degree of the valve 22 may be increased as the heater temperature T is higher, and the flow rate of the cooling air on the second passage 32 side may be increased. The higher the heater temperature T is, the higher the heater temperature T is. The set temperature (cooling temperature) may be lowered.

  The low temperature control has been described on the premise that the control is performed in the single electronic control device 9. However, even if the functions are distributed to various control devices mounted on the vehicle 10, the control may be performed. Good. For example, in the case of the vehicle 10 including an engine ECU that controls the engine 11, a motor ECU that controls the motor 1, and the like, the generator control unit 9B and the motor control unit 9A may be dispersedly arranged in each ECU. The same applies to the specific configuration for acquiring the battery temperature, and the low temperature control start condition may be determined using the battery temperature calculated by the battery ECU that manages the state of the battery 3.

1 Motor (electric motor)
2 Generator (generator)
3 Battery 4 Up / Down converter (transformer)
6 High Voltage Circuit 9 Electronic Controller 9A Motor Controller 9B Generator Controller 9C Transformer Controller 9D Step-Down Controller 9E Heater Controller 9F Cooling Air Controller 10 Vehicle 11 Engine 15 Battery Temperature Sensor 16 Heater 17 PWM Controller ( Modulator)
18 Fan 19 Heater temperature sensor 20 Battery pack 21 Heat exchanger 22 Valve 23 Outside fan 24 Vehicle speed sensor 31 First passage 32 Second passage

Claims (6)

An electric motor for driving a vehicle and a generator driven by an engine are arranged in a high voltage circuit, a battery for driving the vehicle is arranged in an intermediate voltage circuit having a lower potential than the high voltage circuit, and the high voltage circuit In a vehicle control device having a transformer interposed between the medium voltage circuit and the intermediate voltage circuit,
A heater that operates with the power of the high-voltage circuit and raises the temperature of the battery;
A temperature sensor for detecting the temperature of the heater;
A heater control unit that calculates the maximum output of the heater based on the temperature detected by the temperature sensor and controls the heater with a value obtained by multiplying the maximum output by a predetermined ratio as a target output;
A vehicle control device comprising: The vehicle control device according to claim 1, wherein the heater control unit calculates the maximum output as a smaller value as the temperature of the heater is higher. 3. The vehicle control according to claim 1, wherein the heater control unit sets the predetermined ratio based on a fluctuation characteristic related to an output difference between the generated power of the generator and the power consumption of the electric motor. 4. apparatus. The vehicle control device according to claim 1, wherein the heater control unit sets the predetermined ratio to 0.5. A modulator is provided on a circuit connecting the heater and the high voltage circuit, and modulates a direct current of the high voltage circuit into a pulse signal and outputs the pulse signal to the heater. The control apparatus of the vehicle in any one of 1-4. The said heater control part controls the said modulator using the total value of the output difference of the electric power generated of the said generator, and the electric power consumption of the said motor, and the said target output, The said characteristic is characterized by the above-mentioned. Vehicle control device.

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