JP2004092401A - Electric power regenerating device for vehicular cooling fan motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an electric power balance in a vehicle, and to save a cost as compared with a conventional one. <P>SOLUTION: A boosting module 12 for charging a battery 8 by boosting voltage induced between terminals of a motor 3 by receiving traveling wind and rotating a cooling fan 2, is added. While the motor 3 is not driven, a regenerating control portion 13a of an engine ECU 13 outputs a PWM signal S7 to a gate of an MOSFET10 during high speed traveling not less than 80km/h and when the battery 8 is not in a full charge state. A frequency fPWM of the PWM signal S7 is made to be not less than 10kHz, and a duty cycle is made to be generally 80%. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a power regeneration device for a vehicle cooling fan motor that drives a vehicle cooling fan attached to a portion that receives traveling wind.
[0002]
[Prior art]
2. Description of the Related Art A vehicle (for example, an automobile) is provided with a cooling fan for cooling a radiator of an engine and a condenser of an air conditioner, and the cooling fan is conventionally driven by a DC motor (with a brush). ing. With this cooling system, unlike the configuration in which the cooling fan is connected to the output shaft of the engine and driven to rotate, the cooling fan can be driven, stopped, set the rotation speed, etc. without depending on the rotation state of the engine. Will be able to
[0003]
[Problems to be solved by the invention]
However, since the cooling fan motor that rotates the cooling fan is driven by receiving power supply from the battery, the charge / discharge balance of the battery, that is, the power between the generated power and the power consumption in the vehicle is lower than in the case of the engine drive. The balance will worsen.
[0004]
Japanese Unexamined Patent Application Publication No. 2002-61512 discloses that when a cooling fan is rotated by receiving a traveling wind, power generation is improved by regenerating power generation energy output from a cooling fan motor with the rotation. Means for doing so are disclosed. And, specifically, there is provided a rotation speed detecting means for detecting a rotation speed of the cooling fan motor, and when the rotation speed detected by the rotation speed detection means is equal to or higher than a predetermined value, the power generation energy is regenerated. It is configured.
[0005]
However, aside from a brushless motor having a function of detecting the rotation speed by its driving device itself, in the case of a DC motor with a brush which is currently the mainstream as a cooling fan motor, the rotation speed detection means is used. Has to be newly provided, and it has been difficult to adopt the existing control device because the cost is increased.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power regeneration device for a vehicle cooling fan motor that can improve the power balance of a vehicle and can be configured at lower cost than before.
[0007]
[Means for Solving the Problems]
According to the first aspect, when the vehicle travels, the vehicle cooling fan and the vehicle cooling fan motor rotate at a speed corresponding to the traveling wind. When the vehicle cooling fan motor is in a non-driving state and the speed of the vehicle is equal to or higher than a predetermined value, the regenerative unit receives the regeneration command from the regenerative control unit and reduces the generated energy of the vehicle cooling fan motor. Because of the regeneration, the power balance in the vehicle can be improved.
[0008]
Since the speed of the vehicle used to determine whether or not to regenerate has already been detected by the engine control of the vehicle, etc., unlike the conventional configuration, it is newly detected for the regenerative control of the vehicle cooling fan motor. There is no need to provide a device, and costs can be reduced. The relationship between the vehicle speed and the rotation speed of the vehicle cooling fan motor and the relationship between the vehicle speed and the regenerative power of the vehicle cooling fan motor are affected by natural winds and the like. In the case of the same model having the same model and the same number and location of the vehicle cooling fans, the results agree well with the results measured in advance. Therefore, sufficient control accuracy can be obtained by detecting the speed of the vehicle without directly detecting the rotation speed of the vehicle cooling fan motor.
[0009]
Further, when the regenerative means is operated when the speed of the vehicle is lower than the predetermined value, the braking force of the vehicle cooling fan motor increases, the cooling capacity decreases, and the operation frequency of the vehicle cooling fan increases, which results in consumption. Electric power increases. Further, when the power generation voltage of the vehicle cooling fan motor is boosted by using the windings of the DC motor with brush, the life of the brush is shortened due to the generation of spark due to the surge voltage. Therefore, in this means, the regenerative means is operated when the speed of the vehicle is equal to or higher than the predetermined value, thereby improving the power balance and the life of the motor.
[0010]
According to the second aspect of the present invention, the regenerative control means stores (charges) the generated energy regenerated from the vehicle cooling fan motor in the electric power storage means (for example, a battery). For example, even in the case where it changes every moment according to the change in the running state of the vehicle, it is possible to effectively use the regenerated energy. In addition, since the regeneration control unit instructs the regenerative operation on condition that the power storage unit is not in the full storage state, it is possible to prevent an excessive storage state from occurring in the power storage unit.
[0011]
According to the means described in claim 3, when the switching element is turned on, a current flows through the motor winding through the switching element by the induced voltage of the vehicle cooling fan motor, and when the switching element is turned off, the current flows through the diode. It is returned to the power supply side. According to this means, even when the rotation speed of the motor, that is, the induced voltage is low, it is possible to regenerate while increasing the induced voltage.
[0012]
In this case, by setting the frequency of the PWM regenerative command signal given to the switching element to 10 kHz or more and setting the duty ratio to about 80%, a large regenerative current can be obtained while suppressing the decrease in the rotational speed of the vehicle cooling fan. Therefore, the power generation energy can be regenerated most efficiently including the loss of the switching element.
[0013]
According to the fourth aspect, similarly to the first aspect, when the vehicle cooling fan motor is not in the power running state and the speed of the vehicle is equal to or higher than the predetermined value, the regenerative means operates in the regenerative operation mode. Is performed to regenerate the generated energy output from the vehicle cooling fan motor, so that the power balance in the vehicle can be improved. Further, according to the present invention, since the driving means for driving the vehicle cooling fan motor has the regenerative operation function, the configuration can be simplified and the cost can be reduced as compared with the configuration in which the regenerating means is separately provided. This means is applicable, for example, when the vehicle cooling fan motor is a brushless motor.
[0014]
According to the means described in claims 5 and 6, the same operations and effects as those of the inventions described in claims 2 and 3 can be obtained.
[0015]
According to the means described in claim 7, since the regenerative control means is constituted by an existing electronic control device for engine control, when the present means is employed in the conventional configuration, only the regenerative means is newly added. Can be added, and the cost can be further reduced.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an electric configuration of a fan control device used in a vehicle (here, an automobile). The fan control device 1 drives a brushed DC motor 3 (corresponding to a vehicle cooling fan motor) for rotating a cooling fan 2 (corresponding to a vehicle cooling fan) and regenerates energy generated by the motor 3. It operates as a power regeneration device.
[0017]
The cooling fan 2 cools the condenser 4 through which the refrigerant of the vehicle air conditioner passes and the radiator 5 through which the engine cooling water passes. The cooling fan 2, the motor 3, the condenser 4 and the radiator 5 are arranged in front of the vehicle. Located in the department. For this reason, when the vehicle travels and receives a traveling wind from the front, the traveling wind passes through the condenser 4 and the radiator 5 in order to contribute to cooling thereof, and thereafter is given to the cooling fan 2.
[0018]
The positive terminal of the motor 3 is connected to the positive terminal of a battery 8 (corresponding to power storage means) via a relay switch 6 and an ignition switch 7 in series, and the negative terminal is connected to ground (vehicle ground). The battery 8 is connected to the negative terminal of the battery 8 through the battery. A diode 9 having an anode on the motor 3 side is connected in parallel to the relay switch 6. An N-channel MOSFET 10 (anode) is connected to a positive terminal (anode of the diode 9) and a negative terminal (ground) of the motor 3, respectively. (Corresponding to a switching element). The MOSFET 10 is connected to a reflux diode 11 having the illustrated polarity. The step-up module 12 (corresponding to regenerative means) constituted by the diode 9 and the MOSFET 10 is attached to the motor 3 integrally or in the vicinity of the motor 3.
[0019]
An engine ECU (Electronic Control Unit) 13 is an electronic control unit that centrally controls a plurality of controls related to the engine, such as fuel injection control, ignition timing control, and idle speed control, and supplies control power Vcc from a power supply IC (not shown). It is designed to operate in response to this. The engine ECU 13 receives a vehicle speed signal S1 from a vehicle speed sensor and receives a charge permission signal S2 from a controller (alter regulator) of the alternator. The charge permission signal S2 becomes H level when the battery 8 is not in the fully charged state.
[0020]
Further, the engine ECU 13 receives an engine coolant temperature signal S3, an on / off signal (clutch signal) S4 of a magnet clutch for transmitting engine power to a compressor of the air conditioner, and a refrigerant high pressure signal S5 indicating an increase in pressure of the refrigerant of the air conditioner. The engine control is performed using these signals, and the control signal S6 of the relay switch 6 is output. The clutch signal S4 is turned on (H level) when the heat exchange capacity of the evaporator of the air conditioner is reduced, and the refrigerant high pressure signal S5 is a refrigerant pressure higher than the reference value due to insufficient cooling of the condenser 4 or high load operation of the compressor. When turned on, it is turned on (H level).
[0021]
Further, the engine ECU 13 includes a regenerative control unit 13a (corresponding to a regenerative control unit) for regenerating the generated energy of the motor 3, and when a predetermined condition is satisfied as described later, the PWM signal S7 ( (Corresponding to a PWM regeneration command signal). The regenerative control unit 13a is software-processed by the CPU, but may be configured by hardware. The above-mentioned battery 8, booster module 12, and regenerative controller 13a constitute a power regenerating device according to the present invention.
[0022]
Next, the operation of the present embodiment will be described with reference to FIGS.
The engine ECU 13 determines whether the condenser 4 and the radiator 5 need to be cooled based on the temperature signal S3, the clutch signal S4, the refrigerant high-pressure signal S5, and the like, and outputs a control signal S6 when it is determined that it is necessary. Close the relay switch 6. As a result, a current flows from the battery 8 to the motor 3 via the ignition switch 7 and the relay switch 6, and the motor 3 and thus the cooling fan 2 are driven to rotate. On the other hand, when the engine ECU 13 determines that cooling by the cooling fan 2 is unnecessary, the engine ECU 13 stops outputting the control signal S6 and opens the relay switch 6.
[0023]
When the vehicle travels while the relay switch 6 is in the open state, the cooling fan 2 receives the traveling wind and rotates. In this case, since the induced voltage induced between the terminals of the motor 3 is lower than the battery voltage VB, the induced voltage of the motor 3 is boosted by the boosting module 12. Hereinafter, the regeneration control of the motor 3 based on the vehicle speed will be described.
[0024]
When the PWM signal S7 becomes H level when the relay switch 6 is open, the charge permission signal S2 is H level, and the cooling fan 2 receives the running wind and the motor 3 rotates, the MOSFET 10 is turned on, and the motor A short circuit current due to the induced voltage flows through the winding No. 3. Thereafter, when the PWM signal S7 changes from the H level to the L level, the MOSFET 10 is turned off and the diode 9 is turned on, and the short-circuit current flowing in the winding of the motor 3 flows from the motor 3 to the battery 8 through the diode 9 and the ignition switch 7. . The power generation energy of the motor 3 is regenerated to the battery 8 by turning on and off the MOSFET 10 at a predetermined frequency and duty ratio.
[0025]
FIG. 2 shows the relationship between the vehicle speed (km / h) and the fan speed (rpm) when the vehicle is driven in a windless environment with no natural wind with the relay switch 6 in the open state. The solid line in the figure indicates the characteristics when the regenerative control is performed by giving the PWM signal S7 from the engine ECU 13 to the boost module 12, and the broken line indicates the characteristics when the regenerative control is stopped. When the fan rotation speed becomes 180 rpm or less, the rotation becomes unstable. FIG. 3 shows the relationship between the vehicle speed (km / h) and the regenerative power (W) when the regenerative control is performed under the same running conditions. The frequency fPWM of the PWM signal S7 when performing the regenerative control is 10 kHz, and the duty ratio is 80%.
[0026]
As can be seen from these figures, when the regenerative control is not performed, the cooling fan 2 starts rotating from around 50 km / h, but when the regenerative control is performed, the braking force is generated in the motor 3 so that the cooling fan 2 is around 70 km / h. , The cooling fan 2 starts to rotate. Actually, regenerative electric power can be obtained only in the case of high-speed running of 80 km / h or more.
[0027]
On the other hand, during high-speed driving, the water pump and compressor obtain sufficient driving force from the engine to provide sufficient engine cooling water and refrigerant flow for the air conditioner.Therefore, there is room for both cooling and cooling capacity. 2 is in an off state, that is, a state in which power regeneration is possible. Therefore, even if the regenerative control is performed only during high-speed running, electric power can be effectively regenerated in accordance with the cooling and cooling characteristics of the vehicle.
[0028]
On the other hand, if the regenerative control is always performed regardless of the vehicle speed when the relay switch 6 is in the open state, the braking force of the motor 3 increases, the cooling capacity of the cooling fan 2 decreases, and the cooling fan 2 The frequency of operation increases, and on the contrary, the power consumption increases. Further, when the DC voltage of the brushed DC motor 3 is increased by using the windings thereof, sparks are generated due to the surge voltage, which promotes brush wear and shortens the service life. Many vehicles are traveling at low speeds and medium speeds of less than 80 km / h longer than at high speeds. Therefore, in terms of life and efficiency, regenerating at low speeds and medium speeds of less than 80 km / h. It is better not to perform the control, and it is desirable to perform the regenerative control only during high-speed running at 80 km / h or more.
[0029]
Subsequently, characteristics of the regenerative control will be described.
FIG. 4 shows waveforms of the motor induced voltage Vm and the PWM signal S7 when the induced voltage of the motor 3 is boosted by the boost module 12. FIG. 4A shows a case where the frequency fPWM of the PWM signal S7 is low, and FIG. 4B shows a case where the frequency fPWM of the PWM signal S7 is high. The duty ratios are both 80%.
[0030]
Since the regenerative control is, in other words, the braking control of the motor 3, the longer the on-time, that is, the braking time of the MOSFET 10, the larger the short-circuit current (the regenerative current), but the greater the braking, the lower the speed of the cooling fan 2. Becomes larger. For this reason, optimal control for increasing the regenerative power while suppressing the speed reduction of the cooling fan 2 is required.
[0031]
FIG. 5 shows test results obtained by changing the frequency fPWM of the PWM signal S7 variously, and shows the relationship between the duty ratio and the regenerative current value (effective value). FIG. 6 shows the relationship between the frequency fPWM at a duty ratio of 80% and the regenerative current value (effective value). The running speed in FIGS. 5 and 6 is 100 km / h, and the rated power of the motor 3 is 120 W. Although not shown, almost the same result is obtained when the traveling speed is 80 km / h.
[0032]
In these figures, when the duty ratio is low, the regenerative current tends to increase when the frequency fPWM is low, and when the duty ratio is high, the regenerative current tends to increase when the frequency fPWM is high. The maximum regenerative current value increases as the frequency fPWM increases. When the frequency fPWM becomes 10 kHz or more, the tendency of the regenerative current to increase with an increase in the frequency fPWM slows down.
[0033]
This is because the higher the frequency fPWM, the greater the number of times a surge voltage is generated when the MOSFET 10 is turned off, but the regenerative current reaches a limit value at a frequency of 10 kHz or more from the followability of motor braking. The higher the duty ratio is, the longer the braking time is. However, the regenerative current is maximized at a duty ratio of 80% due to the efficiency of the MOSFET 10 and the braking force.
[0034]
From these test results, in the case of a motor 3 of a rated power of 80 W to 200 W class, which is generally used as a drive motor for the cooling fan 2 in a vehicle, the frequency fPWM of the regenerative control is set to 10 kHz or more, for example, about 16 kHz to 20 kHz, It can be seen that a larger regenerative current can be obtained by setting the duty ratio to approximately 80%.
[0035]
As described above, the fan control device 1 of the present embodiment includes the boosting module 12, and the engine ECU 13 performs the boosting module 12 when the motor 3 is not driven and the speed of the vehicle is 80 km / h or more. Output the PWM signal S7 to regenerate the energy generated by the motor 3 to the battery 8, so that the power balance in the vehicle can be improved. Further, even when the rotation speed of the motor 3, that is, the induced voltage is low, it is possible to regenerate while increasing the induced voltage.
[0036]
Since the vehicle speed used to determine whether or not to regenerate is already detected and used by the engine ECU 13 in the original engine control, there is no need to provide a new detection device for regenerative control of the motor 3. Costs can be reduced. Although the relationship between the vehicle speed and the rotation speed of the motor 3 and the relationship between the vehicle speed and the regenerative power of the motor 3 are affected by natural wind and the like, the type of the motor 3 and the number and location of the cooling fans 2 are the same. For the same vehicle type, the result matches well with the result measured in advance. Therefore, sufficient control accuracy can be obtained by using the detected vehicle speed without directly detecting the rotation speed of the motor 3.
[0037]
Further, since the regenerative control is performed only at the time of high-speed running at a vehicle speed of 80 km / h or more, the influence of the decrease in the cooling capacity due to the increase in the braking force of the motor 3 is small, and the power balance is deteriorated with the increase in the operation frequency of the cooling fan 2 Can be prevented. In addition, since the regenerative control is not performed during low-speed / medium-speed running at less than 80 km / h, it is possible to minimize the brush deterioration of the motor 3 due to the generation of sparks due to the surge voltage.
[0038]
Since the regenerated power is charged in the battery 8, the regenerated power can be effectively used even if the regenerated power changes every moment according to a change in the running state of the vehicle such as the vehicle speed. It can be used. Further, the engine ECU 13 instructs the regenerative operation based on the charge permission signal S2 on condition that the battery 8 is not fully charged, so that the battery 8 can be prevented from being overcharged.
[0039]
Further, in the present embodiment, by setting the frequency fPWM of the PWM signal S7 to 10 kHz or more and the duty ratio thereof to approximately 80%, it is possible to obtain a large regenerative current while suppressing a decrease in the rotation speed of the cooling fan 2. It is possible to regenerate the power generation energy most efficiently including the loss of the MOSFET 10.
[0040]
The present invention is not limited to the embodiment described above and shown in the drawings. For example, the present invention can be modified or expanded as follows.
A brushless motor may be used as the vehicle cooling fan motor. The brushless motor is driven by an inverter device (drive means). In this case, the engine ECU 13 outputs a regenerative command signal when the brushless motor is not in the power running state and the vehicle speed is, for example, 80 km / h or more, and the inverter device performs regenerative operation to regenerate the energy generated by the brushless motor. I do. According to this configuration, since the inverter device that drives the brushless motor has the regenerative operation function, the configuration can be simplified and the cost can be reduced as compared with the configuration in which the regenerating means is separately provided.
[0041]
In the above-described embodiment, the regenerative control unit as the regenerative control unit is provided inside the engine ECU 13. However, the regenerative control unit may be integrated with the booster module 12 or may be provided near the booster module 12. good.
Instead of returning the regenerative power from the motor 3 to the battery 8, the regenerative power may be directly used by, for example, making the voltage constant through a regulator.
The switching element used in the step-up module 12 or the inverter device is not limited to the MOSFET, but may be a bipolar transistor, an IGBT, or the like.
[Brief description of the drawings]
FIG. 1 is an electric configuration diagram of a fan control device according to an embodiment of the present invention; FIG. 2 is a diagram showing a relationship between a vehicle speed and a fan speed; FIG. 3 is a diagram showing a relationship between a vehicle speed and a regenerative electric power; FIG. 4 is a diagram showing waveforms of a motor induced voltage and a PWM signal. FIG. 5 is a diagram showing a relationship between a duty ratio of a PWM signal and a regenerative current value. FIG. 6 is a diagram showing a relationship between a frequency of the PWM signal and a regenerative current value. Figure [Explanation of symbols]
2 is a cooling fan (vehicle cooling fan), 3 is a DC motor (vehicle cooling fan motor), 8 is a battery (power storage means), 9 is a diode, 10 is a MOSFET (switching element), and 12 is a booster module (regeneration) Means), 13a is a regeneration control unit (regeneration control means).

Claims (7)

Regenerative means capable of regenerating power generation energy of a vehicle cooling fan motor driving a vehicle cooling fan attached to a portion receiving the traveling wind,
Regenerative control means for instructing the regenerative means to perform a regenerative operation on condition that the vehicle cooling fan motor is not driven and the speed of the vehicle is equal to or higher than a predetermined value. A power regeneration device for a cooling fan motor for a vehicle, comprising: The regenerative means comprises an electric power storage means capable of storing energy regenerated,
2. The vehicle cooling fan according to claim 1, wherein the regenerative control unit is configured to instruct the regenerative unit to perform a regenerative operation on condition that the electric power storage unit is not in a full storage state. Motor power regeneration device. The regenerative means includes a switching element capable of short-circuiting a winding of the vehicle cooling fan motor, and a diode for flowing a short-circuit current flowing through the winding to a power supply side in response to the switching element being turned off from on. It is configured with
3. The vehicle cooling system according to claim 1, wherein a frequency of a PWM regeneration command signal given to the switching element by the regeneration control unit is set to 10 kHz or more, and a duty ratio thereof is set to approximately 80%. Power regeneration device for fan motor. A drive unit capable of powering operation and a regenerative operation of a vehicle cooling fan motor for driving a vehicle cooling fan attached to a portion receiving the traveling wind; and the driving unit stops the powering operation of the vehicle cooling fan motor. And a regenerative control means for instructing the drive means to perform regenerative operation on condition that the speed of the vehicle is equal to or higher than a predetermined value. Power regeneration device. The power storage means capable of storing the energy regenerated by the drive means,
5. The vehicle cooling fan according to claim 4, wherein the regenerative control unit is configured to instruct the driving unit to perform a regenerative operation on condition that the power storage unit is not in the full storage state. Motor power regeneration device. A switching element capable of short-circuiting a winding of the vehicle cooling fan motor; and a diode for flowing a short-circuit current flowing through the winding to a power supply in response to the switching element being turned off from on. It is configured with
6. The vehicle cooling system according to claim 4, wherein a frequency of a PWM regeneration command signal given to said switching element by said regeneration control means is set to 10 kHz or more, and a duty ratio thereof is set to approximately 80%. Power regeneration device for fan motor. The power regeneration device for a vehicle cooling fan motor according to any one of claims 1 to 6, wherein the regeneration control means includes an electronic control device that controls an engine.

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