JP5402585B2 - Vehicle generator - Google Patents

Description

  The present invention relates to a vehicular generator mounted on a passenger car, a truck, or the like.

Although the generator for vehicles is mounted on an engine block, in recent years, heat dissipation has been reduced due to higher density in the engine room, and the temperature environment has become severe. Under such circumstances, it is necessary to take measures to prevent an excessive increase in the temperature of the vehicle generator itself. As a conventional technique as such a preventive measure, a method has been proposed in which when the temperature of the vehicle generator reaches a predetermined temperature, the output current is suppressed to keep the temperature of the vehicle generator within an allowable limit. (For example, see Patent Documents 1-3.)
Among them, in the region above the limit operating temperature, the adjustment voltage has a negative temperature gradient characteristic to reduce the output voltage of the vehicle generator, and the supply voltage from the vehicle generator to the electric load is reduced to generate heat. Attempts have been made to reduce the amount.

  In addition, low idling is promoted to improve fuel economy, and in the low-speed rotation range of the vehicular generator, there is a phenomenon that the output current increases when the output voltage decreases due to the output voltage dependency of the vehicular generator. (For example, refer to Patent Document 4) There is a rotation region in which the temperature of the vehicular generator rises due to a decrease in output voltage. This is because the power consumption due to the resistance component of the stator winding and the current flowing therethrough becomes heat, and the rectifier for rectifying the three-phase alternating current has diodes formed of P-type and N-type semiconductors. This is because the power consumed by the forward voltage drop generated at the PN junction becomes heat and raises the temperature of the vehicular generator.

  Therefore, with an adjustment voltage with a negative temperature gradient provided to prevent an excessive temperature rise in this region, if the output voltage drops in a high temperature environment, the output current increases → the temperature of the vehicle generator rises → Decrease in adjustment voltage → Increase in output current → Increase in temperature of vehicular generator → ... Fall into a vicious circle, and an excessive increase in temperature of the vehicular generator cannot be effectively prevented. In particular, when the temperature of the vehicular generator rises and the adjustment voltage decreases, there is a problem in that the illuminance drop of the headlamps becomes significant due to the lower output voltage of the vehicular generator.

JP-A-8-9567 Japanese National Patent Publication No. 3-502873 JP-T 6-505622 JP 2002-17053 A

  The present invention has been created in view of the above points, and an object of the present invention is to provide a vehicle capable of improving the influence on the illuminance reduction of the lighting device when preventing an excessive temperature increase in a high temperature environment. The purpose is to provide a power generator.

  In order to solve the above-described problems, a vehicle generator according to the present invention has a plurality of field poles and a field winding for magnetizing the field poles, and a rotor driven by the engine, and a fixed A stator wound around the rotor and disposed opposite to the field pole of the rotor; a rectifier that rectifies the AC power generated in the stator winding to supply the battery and the electrical load as DC power; A return element connected in parallel to the magnetic winding, a comparison means for comparing the output voltage output from the rectifier and the adjustment voltage set to charge the battery, and connected in series with the field winding And a voltage control device that controls the output voltage to an adjusted voltage by intermittently controlling the switch means based on the comparison result of the comparison means. The voltage control device reduces the adjustment voltage when the temperature of the vehicle generator itself reaches an overheated state regardless of the battery use temperature, and overheats by adjusting the first temperature characteristic of the adjustment voltage corresponding to the battery use temperature. A second temperature characteristic of an adjustment voltage for avoiding a state, and an adjustment voltage temperature characteristic setting means for setting the adjustment voltage; and detecting the rotation speed of the vehicle generator, and detecting the rotation speed of the vehicle generator to a second temperature at a predetermined rotation speed or less. Temperature characteristic switching means for switching the adjustment voltage set by the adjustment voltage temperature characteristic setting means to a first adjustment voltage higher than the adjustment voltage according to the second temperature characteristic is invalidated.

  Below the specified number of revolutions, when an electrical load that exceeds the power generation capacity of the vehicle generator is connected, the output current increases as the output voltage decreases due to the output voltage dependency of the vehicle generator, and the stator winding There is a rotation region where the heat generated by the resistance component and the heat generated by the rectifying action of the rectifier increase and the temperature of the vehicle generator itself increases. The adjustment voltage set value for adjusting the output voltage of the vehicular generator does not shift to the second temperature characteristic of the adjustment voltage for preventing excessive temperature rise built in the voltage control device. By giving priority to voltage recovery by setting the first adjustment voltage higher than the adjustment voltage, it is possible to stabilize the illuminance of the lighting device particularly during night driving from low speed to low speed. In addition, the recovery of the battery voltage at the time of turning on the electric load is accelerated, the lowered voltage at the output terminal of the vehicle generator is restored to the original voltage, and the decrease in output current (decrease due to output voltage dependence) is accelerated. Therefore, power consumption in the stator and rectifier is reduced, and heat generation due to these can be suppressed.

Further, the maximum output current of the above-described vehicle generator is proportional to the output voltage when the rotational speed is higher than the predetermined rotational speed, and depends on the output voltage that is inversely proportional to the output voltage when the rotational speed is lower than the predetermined rotational speed. The predetermined rotation speed is set to a rotation speed that does not have output voltage dependency . By setting the predetermined number of revolutions in this way, it is possible to reliably prevent adverse effects such as a decrease in illuminance of the lighting device and heat generation in the stator and rectifier due to output voltage dependency.

  The first adjustment voltage described above is preferably an adjustment voltage based on the first temperature characteristic. Thereby, the first temperature characteristic for adjusting voltage setting for battery charging can be used, and the configuration can be simplified.

  Further, it is desirable that the above-described predetermined rotational speed is set higher than the rotational speed corresponding to the idle rotational speed of the engine. As a result, it is possible to cope with an engine in which the idling speed is set lower than the speed corresponding to the predetermined speed, and it can be applied to a low fuel consumption vehicle with low idling.

  The second temperature characteristic described above desirably has a negative temperature gradient. In particular, it is desirable that the second temperature characteristic has a larger negative temperature gradient than the first temperature characteristic. If the vehicle generator continues to generate electricity in an overheated state, the adjustment voltage is attenuated by the second temperature characteristic with a negative temperature gradient to prevent excessive temperature rise of the vehicle generator. Suppresses the amount of power generated, protects the vehicle generator from overheating, and continues to charge the battery and supply power to other electrical loads with a low adjustment voltage when the overheating continues. Can be secured.

It is a figure which shows the structure of the voltage control apparatus of one Embodiment. It is a figure which shows the relationship between the adjustment voltage produced | generated by the adjustment voltage temperature characteristic setting circuit, and the temperature of a voltage control apparatus. It is a figure which shows the modification of an adjustment voltage temperature characteristic. It is a figure which shows the modification of an adjustment voltage temperature characteristic.

  A voltage control apparatus according to an embodiment to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a voltage control apparatus according to an embodiment to which the present invention is applied. In addition, a connection state between the voltage control apparatus and a vehicle generator, a battery, and an electric load is shown.

  In FIG. 1, the vehicle generator 1 includes a field winding 11, a stator winding 12, a rectifier 13, and a voltage control device 2. The field winding 11 is for magnetizing a plurality of field poles (not shown). The field winding 11 is wound around the field poles to form a rotor, and generates a magnetic field when energized.

  The stator winding 12 is a multiphase winding (for example, a three-phase winding), and is wound around a stator core (not shown) disposed opposite to the field pole of the rotor to constitute a stator. doing. The stator winding 12 generates an electromotive force due to a change in the magnetic field generated by the field winding 11. An AC output induced in the stator winding 12 is supplied to the rectifier 13. In addition, one phase of the stator winding 12 is connected to the P terminal of the voltage control device 2, and an AC output for one phase of the stator winding 12 is input to the P terminal.

  The rectifier 13 performs full-wave rectification on the AC output of the stator winding 12 in order to supply AC power generated in the stator winding 12 to the battery 3 and the electric load 4 as DC power. The output of the rectifier 13 is taken out as the output of the vehicular generator 1 and supplied to the battery 3, the electric load 4, the headlamp 7, or other electric loads.

  The output of the vehicular generator 1 varies according to the rotational speed and output voltage of a rotor that is rotationally driven by an engine (not shown) or the field current flowing through the field winding 11. The output voltage and field current are controlled by the voltage control device 2.

  The voltage control device 2 includes a power supply circuit 21, an adjustment voltage control circuit 22, a switch element 23, a freewheeling diode 24, and a temperature characteristic switching circuit 25.

  The power supply circuit 21 is connected to an IG (ignition) terminal and connected to the battery 3 via the key switch 6. The power supply circuit 21 operates when the key switch 6 is turned on, and supplies a power supply voltage (operating voltage) Vcc to each element constituting each circuit in the voltage control device 2.

  The adjustment voltage control circuit 22 receives the output voltage of the vehicle generator 1, and the output terminal of the voltage comparator 221 in the output stage is connected to the switch element 23. Details of the adjustment voltage control circuit 22 will be described later.

  The switch element 23 is configured using a power transistor, the gate is connected to the output terminal of the voltage comparator 221, and the drain is connected to the output terminal (B terminal) of the vehicle generator 1 via the freewheeling diode 24. The source is connected to the E terminal and is grounded by the engine block (not shown) via the E terminal (frame) of the vehicle generator 1. The switch element 23 has a drain connected to the field winding 11 via the F terminal. When the switch element 23 is turned on, a current flows through the field winding 11. When the switch element 23 is turned off, the supply of this current is stopped. The

  The freewheeling diode 24 is connected in parallel with the field winding 11 and recirculates the current flowing through the field winding 11 when the switch element 23 is turned off. The temperature characteristic switching circuit 25 has an input terminal connected to the P terminal and an output terminal connected to the adjusted voltage temperature characteristic setting circuit 224 in the adjusted voltage control circuit 22.

  The adjustment voltage control circuit 22 includes a voltage comparator 221, resistors 222 and 223, and an adjustment voltage temperature characteristic setting circuit 224. In order to detect the B terminal voltage of the vehicle generator 1, an input voltage V <b> 1 obtained by dividing the B terminal voltage by the resistors 222 and 223 is input to the negative input terminal of the voltage comparator 221. Further, a reference voltage V2 corresponding to an adjustment voltage for adjusting the B terminal voltage to a predetermined voltage is input to the plus input terminal. The adjustment voltage temperature characteristic setting circuit 224 detects the temperature of the power generation control device 2, and generates the reference voltage V2 based on the detected temperature.

FIG. 2 is a diagram showing the relationship between the adjustment voltage V2 generated by the adjustment voltage temperature characteristic setting circuit 224 and the temperature of the voltage control device 2. As shown in FIG. As shown in FIG. 2, the relationship between the adjustment voltage V2 generated by the adjustment voltage temperature characteristic setting circuit 224 and the temperature (adjustment voltage temperature characteristic) is as follows.
(When generator speed N _ALT is less than N1)
A characteristic (first temperature characteristic) indicated by a solid line, for example, ± 0 mV / ° C to −10 mV / ° C
(When generator speed N _ALT is greater than N1)
When the temperature T of the voltage control device 2 is equal to or lower than T2: A characteristic indicated by a solid line When the temperature T of the voltage control device 2 is higher than T2: B characteristic having a negative temperature gradient indicated by a one-dot chain line (second temperature characteristic) For example, -100 mV / ° C to -200 mV / ° C
The A characteristic described above is a temperature characteristic of the adjustment voltage corresponding to the operating temperature of the battery 3. In this embodiment, instead of detecting the temperature of the battery 3, the temperature of the voltage control device 2 correlated with the temperature of the battery 3 is detected and used as the temperature of the battery 3. The B characteristic is a temperature characteristic of the adjustment voltage for reducing the adjustment voltage when the temperature of the vehicle generator 1 itself reaches an overheated state regardless of the operating temperature of the battery 3 to avoid this overheated state. is there.

  The rotation speed N1 is dependent on the output voltage (the maximum output current of the vehicle generator 1 is proportional to the output voltage when the rotation speed is higher than N1, and becomes the output voltage when the rotation speed is lower than N1. The rotation speed does not have an inversely proportional characteristic, and is set to a value higher than the rotation speed corresponding to the idle rotation speed of the engine.

The temperature characteristic switching circuit 25 takes in the rectangular wave voltage generated in the stator winding 12 from the P terminal and detects the generator rotational speed _NALT . Further, the temperature characteristic switching circuit 25 sets the detected engine speed N _ALT to a predetermined speed N1 (for example, 2000 rpm, engine speed corresponding to idling when converted to engine speed and engine speed corresponding to traveling). L signal (low level signal) when N _ALT is less than or equal to N1, and H signal (high level signal) when N _ALT is higher than N1. Output to the adjustment voltage temperature characteristic setting circuit 224.

  The above-described freewheeling diode 25 corresponds to the freewheeling element, the adjusted voltage temperature characteristic setting circuit 224 corresponds to the adjusted voltage temperature characteristic setting means, and the temperature characteristic switching circuit 25 corresponds to the temperature characteristic switching means.

  The voltage control apparatus 2 of this embodiment has such a configuration, and the operation thereof will be described next. When the key switch 6 is turned on, each element is biased with a constant operating voltage generated by the power supply circuit 21 in the voltage control device 2, and each circuit starts operating.

  In the voltage comparator 221 of the adjustment voltage control circuit 22, since the input voltage V1 is lower than the reference voltage V2, the output becomes high level. Accordingly, the switch element 23 is turned on, and the initial exciting current is supplied to the field winding 11. The magnetizing force of the field pole is increased by the initial excitation current.

  Thereafter, the engine is started by a starter (not shown), whereby the rotor of the vehicular generator 1 is rotated, and the voltage (generated voltage) generated in the stator winding 12 is increased. When the generated voltage further rises and the input voltage V1 for detecting the B terminal voltage of the vehicular generator 1 reaches the reference voltage V2 (the voltage corresponding to the adjusted voltage VB = 14 V at room temperature T1 (FIG. 2)), the voltage comparator The output of 221 changes to a low level. Therefore, the switch element 23 is turned off, and the field current is reduced. By repeating such control, the B terminal voltage of the vehicular generator 1 is adjusted to the first adjustment voltage (for example, VB = 14V).

  In a state after the engine is started and before the vehicle travels, in the temperature range where the temperature T of the voltage control device 2 is equal to or lower than T2, the reference voltage V2 corresponding to the A characteristic shown in FIG. The vehicular generator 1 is controlled by the adjustment voltage generated and corresponding to the A characteristic.

Next, the operation when the temperature T of the voltage control device 2 is higher than T2 when the vehicle is traveling (N1 <N _ALT ) will be described. The temperature characteristic switching circuit 25 outputs an H signal when the generator rotational speed N _ALT is higher than N1, and switches the characteristic of the reference voltage V2 generated by the adjustment voltage temperature characteristic setting circuit 224 to the B characteristic.

  By the way, the ambient temperature that rises due to the operation of the engine and accessories mounted in the engine room is suppressed so as not to exceed an allowable range by using a cooling device such as a radiator or a fan. However, if the temperature in the engine room rises beyond the allowable range due to a failure of the cooling device or the like, the intake air temperature of the vehicular generator 1 rises, and the cooling fan built in the vehicular generator 1 1 Heat generation (temperature rise) from the stator, rotor, rectifier 13 and voltage control device 2 (especially switch element 23) due to its own power generation cannot be dissipated and the vehicle generator 1 operates while maintaining an overheated state. Will do.

  In such a case, the generated voltage of the vehicular generator 1 is suppressed by lowering the charging voltage to the battery 3 by using the B characteristic that rapidly attenuates the adjustment voltage corresponding to the high temperature of the voltage control device 2. The battery 3 is charged while suppressing heat generation.

Next, the operation when the temperature T of the power generation control device 2 becomes higher than T2 near the idle (N _ALT ≦ N1) will be described.

The temperature characteristic switching circuit 25 outputs an L signal when the generator rotation speed N _ALT is N1 or less, and switches the characteristic of the adjustment voltage temperature characteristic setting circuit 224 to the A characteristic. If the adjustment voltage remains in the B characteristic when the temperature T of the voltage control device 2 is higher than T2, the maximum output current of the vehicle generator 1 depends on the magnitude of the output voltage (output voltage dependency). If the output voltage is lowered, the maximum output current increases. For this reason, due to the increase in the maximum output current, the temperature of the stator of the vehicular generator 1 and the rectifier 13 increases, and the adjustment voltage of the power generation control device 2 further decreases according to the B characteristic. And the output voltage of the generator 1 for vehicles is maintained by the reduced adjustment voltage. That is, since the voltage applied to lighting equipment such as the headlamp 7 is reduced, the illuminance is also reduced.

In order to avoid such a situation, in the present embodiment, the temperature T of the power generation control device 2 is T2 when the generator rotational speed _NALT near the engine idle speed (for example, during a traffic jam) is N1 or less. Even if it is higher, the B characteristic is invalidated and the control of the adjustment voltage (first adjustment voltage) by the A characteristic is maintained.

  In the low rotation range below N1, the temperature characteristic (B characteristic) that suddenly lowers the adjustment voltage is stopped, and the temperature characteristic (A characteristic) for charging the battery 3 is changed, so that the lighting device such as the headlamp 7 can be used. A decrease in illuminance can be suppressed. Further, the recovery of the battery voltage when various electric loads such as the electric load 4 and the headlamp 7 are turned on is accelerated, the lowered output voltage of the vehicle generator 1 is increased to the original voltage, and the output current is reduced. Since the reduction (reduction due to output voltage dependency) is accelerated, power consumption in the stator and the rectifier 13 is reduced, and heat generation due to these is suppressed. In other words, by performing such switching control, heat generation of the vehicular generator 1 can be suppressed while improving the illuminance reduction of the lighting device due to the battery voltage drop in a low rotation range of N1 or less.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the embodiment described above, the negative temperature characteristic of each of the A characteristic and the B characteristic has been described as an example as shown in FIG. 2, but the boundary between the A characteristic and the B characteristic is assumed to be a temperature rise. Accordingly, the adjustment voltage may be lowered stepwise (FIG. 3) or curvilinearly (FIG. 4) to switch from the A characteristic to the B characteristic.

  ADVANTAGE OF THE INVENTION According to this invention, the illumination intensity of the illuminating device at the time of low-speed driving | running | working from the idle driving | operation at night can be aimed at. In addition, the recovery of the battery voltage at the time of turning on the electric load is accelerated, the lowered voltage at the output terminal of the vehicle generator is restored to the original voltage, and the decrease in output current (decrease due to output voltage dependence) is accelerated. Therefore, power consumption in the stator and rectifier is reduced, and heat generation due to these can be suppressed.

DESCRIPTION OF SYMBOLS 1 Vehicle generator 2 Voltage control apparatus 3 Battery 4 Electric load 5, 8 Load switch 6 Key switch 7 Headlamp 11 Field winding 12 Stator winding 13 Rectifier 21 Power supply circuit 22 Adjustment voltage control circuit 23 Switch element 24 Freewheeling diode 25 Temperature characteristic switching circuit 221 Voltage comparator 222, 223 Resistance 224 Adjustment voltage temperature characteristic setting circuit

Claims (5)

A rotor having a plurality of field poles and a field winding for magnetizing the field poles, driven by an engine;
A stator wound with a stator winding and disposed opposite to the field pole of the rotor;
A rectifier that rectifies the AC power generated in the stator windings to supply the battery and the electrical load as DC power;
A reflux element connected in parallel to the field winding;
Comparing means for comparing an output voltage output from the rectifier and an adjustment voltage set for charging the battery, and switch means connected in series with the field winding, the comparing means In a vehicle generator comprising: a voltage control device that controls the output voltage to the adjusted voltage by intermittently controlling the switch means based on the comparison result of
The voltage controller is
The first temperature characteristic of the adjustment voltage corresponding to the operating temperature of the battery and the overheating by reducing the adjustment voltage when the temperature of the vehicle generator itself is overheated regardless of the operating temperature of the battery A second temperature characteristic of the adjustment voltage for avoiding a state, and an adjustment voltage temperature characteristic setting means for setting the adjustment voltage;
The rotation speed of the vehicle generator is detected, the second temperature characteristic is invalidated below a predetermined rotation speed, and the adjustment voltage temperature characteristic is set to a first adjustment voltage higher than the adjustment voltage according to the second temperature characteristic. Temperature characteristic switching means for switching the adjustment voltage set by the setting means ,
The maximum output current of the vehicular generator is proportional to the output voltage when the rotational speed is higher than the predetermined rotational speed, and is inversely proportional to the output voltage when the rotational speed is lower than the predetermined rotational speed. It has voltage dependency,
Wherein the predetermined rotation speed, the vehicle generator characterized that you have set the rotational speed without the output voltage dependence. In claim 1,
The vehicular generator, wherein the first adjustment voltage is an adjustment voltage based on the first temperature characteristic. In claim 1 or 2,
The vehicle generator is characterized in that the predetermined rotational speed is set higher than a rotational speed corresponding to an idle rotational speed of the engine. In any one of Claims 1-3,
The vehicular generator according to claim 2, wherein the second temperature characteristic has a negative temperature gradient. In claim 4,
The vehicular generator, wherein the second temperature characteristic has a negative temperature gradient larger than that of the first temperature characteristic.

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