JP4006614B2 - AC generator for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-excited vehicle AC generator that detects the start of power generation by a generator and starts energization of an exciting coil.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. Hei 6-27679 filed by the present applicant discloses a self-excited vehicle that detects that a one-phase generated voltage has exceeded a predetermined level and conducts switching means connected in series to an exciting coil. Has proposed an AC generator.
[0003]
According to this vehicle alternator, a self-excited vehicle alternator that detects the start of power generation by the generator and starts energization of the exciting coil to the exciting coil is disclosed.
[0004]
However, in the above-described technology, when leakage current flows into the armature winding of the generator due to leakage, a noise voltage (voltage different from the normal generation voltage) that should be called leakage voltage is generated by the leakage current. As a result, there is a problem that the exciting current is passed through the exciting coil even though the power generation output cannot actually be obtained.
[0005]
In order to remedy this problem, the above publication attempts to connect the power generation voltage detection end of the power generation detection circuit to which the one-phase power generation voltage is input and the ground end by a bypass resistor and to flow into the armature winding from the outside. It discloses disclosing much of the leakage current to this bypass resistor.
[0006]
Japanese Patent Application Laid-Open No. 3-215200 and Japanese Patent Application Laid-Open No. 8-503308 disclose a technique capable of detecting a signal even when a leak occurs by utilizing differential amplification of two-phase voltages of an armature winding. ing.
[0007]
[Problems to be solved by the invention]
However, in order to suppress erroneous detection of the start of power generation due to the leakage current described above, it is beneficial to reduce the resistance value of the bypass resistor. As a result, the bypass resistor generates power after the power generation of the armature winding is established. This consumes output and leads to problems such as a decrease in overall efficiency and ambient overheating due to heat generated by the bypass resistor. Conversely, it is beneficial to increase the resistance value of the bypass resistor in order to reduce power consumption and heat generation due to the bypass resistor after the power generation of the armature winding is established. The effect which suppresses a detection will fall. In other words, in the technique of the above publication, the resistance value of the bypass resistor must be set within a range where problems such as consumption of the power generation output and heat generation due to the bypass resistor are not serious, and as a result, suppression of erroneous generation start due to leakage current is suppressed. The contradiction that performance was restricted could not be solved.
[0008]
Further, in the technique using the differential amplification of the two-phase voltage of the armature winding described above, the structure of the generator is complicated because the two-phase output voltage signal of the armature is taken into the voltage control device, and the assembly is performed. There are concerns about problems such as an increase in man-hours and a decrease in reliability due to an increase in the number of connection points.
[0009]
The present invention has been made in view of the above problems, and for a vehicle capable of satisfactorily preventing erroneous generation start due to leakage current flowing into the armature winding while suppressing power consumption and heat generation of the bypass resistor. Its purpose is to provide an alternator.
[0010]
[Means for Solving the Problems]
An AC generator for a vehicle according to claim 1, wherein a rotor having a plurality of magnetic poles, a field winding for magnetizing the magnetic poles, an armature coaxially arranged with the rotor and wound with an electric winding And a voltage control of an AC generator for a vehicle that is equipped with a rectifier that rectifies the output voltage of the armature winding and stores the rectified voltage in an in-vehicle power storage means, and controls the output voltage obtained by the rectification When the output voltage of the armature winding exceeds a predetermined voltage threshold, or the frequency of the output voltage of the armature winding exceeds a predetermined frequency threshold And means for permitting energization of the exciting current to the field winding and means for permitting energization of the exciting current connected between the output end of the previous armature winding and a predetermined constant potential end. Resistance value variable means for increasing the resistance value after energization permission; It is characterized in that it comprises.
[0011]
That is, according to the present invention, when the output voltage or its frequency exceeds a predetermined frequency threshold value, energization of the excitation current is permitted, and the resistance value variable connected to the output end of the armature winding after the energization is permitted. Since the resistance value of the means is increased, it is possible to satisfactorily prevent erroneous detection of power generation due to leakage current flowing into the armature winding by setting the resistance value of the resistance value variable means to be small before the power generation start detection. After the start of power generation is detected, the resistance value of the resistance value variable means can be set large to reduce or prevent its power consumption and its heat generation.
[0012]
According to the configuration of claim 2, in the vehicle alternator according to claim 1, since the resistance variable means is composed of a switching means and a resistance element, power consumption and heat generation after detecting the start of power generation. Can be reliably prevented.
[0013]
In addition, the first resistance element that directly connects the output end of the armature winding and the predetermined constant potential end, the switching element, and the output end of the armature winding connected in series with the switching element Even if the leakage current bypass circuit is configured by the second resistance element that connects the predetermined constant potential terminal and the second constant element, the same effect can be obtained.
[0014]
According to the configuration of the third aspect, after the power generation of the vehicle alternator is stopped, the leakage current flowing into the output end of the armature winding is absorbed while suppressing the heat generation of the resistance value variable means. Therefore, it is possible to reliably detect power generation stoppage.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the vehicle alternator of the present invention will be described with reference to the following examples.
[0016]
[Example 1]
An embodiment of an AC generator for a vehicle according to the present invention will be described with reference to FIG.
(Overall configuration and power generation operation)
This vehicle alternator (alternator) has a generator 1 driven by a vehicle engine (not shown) and an excitation current control device (regulator) 2 for controlling the vehicle alternator 1. .
[0017]
The generator 1 includes a three-phase armature coil (armature winding) 4 that is star-connected to each other and wound around a stator core, a three-phase full-wave rectifier (rectifier) 5, and an excitation coil 6. . The generated voltage generated in each phase coil of the armature coil 4 is rectified by the three-phase full-wave rectifier 5 and then supplied to the battery 3 through the power line L1.
[0018]
When the rotor of the generator 1 rotates, a generated voltage is generated in the armature coil 4 by the residual magnetic flux, and the one-phase generated voltage Vac output from one phase coil of the armature coil 4 is applied to the P terminal of the excitation current control device 2. Applied.
[0019]
The excitation current control device 2 will be described below with reference to FIG. 1 which is a circuit diagram.
[0020]
The one-phase generated voltage Vac input to the P terminal is input to the + input terminal of the self-excitation detection comparator 16 through the resistor 15 and compared with the reference voltage (threshold value) V1. When the one-phase generated voltage Vac becomes equal to or higher than the reference voltage V1 (here, 0.4V), the comparator 16 makes the transistor 18 conductive through the resistor 17 and is connected to the base electrode of the pnp transistor 21 for feeding the internal power supply line L2. The transistor 21 is turned on by drawing the potential of the resistor 19 to a low level. The turned-on transistor 21 supplies power from the power supply line L1 to the internal power supply line L2, and raises the internal power supply line L2 to substantially the potential of the power supply line L1.
[0021]
A capacitor 20 is connected between the connection point of the collector of the transistor 18 and the resistor 19 and the grounding point, and the transistor 21 does not operate regardless of the operation of the comparator 16 for one cycle or more of the one-phase generated voltage having a half-wave rectified waveform. Keep on. As a result, the transistor 21 can continue to supply power to the internal power supply line L2.
[0022]
The internal power supply line L2 is connected to the base electrode of the switching transistor 27 through the base current limiting resistor 26. For this reason, the switching transistor 21 that has been turned on turns on the switching transistor 27, and the switching transistor 27 that has been turned on starts energization of the exciting current from the power line L1 to the exciting coil 6, and power generation by the exciting current is started. 28 is a known flywheel diode.
[0023]
When a potential is applied to the power supply line L2 due to the conduction of the transistor 21, a voltage is applied to the B1 terminal and the B2 terminal of the transmission circuit 31, and the transmission circuit has a period of a high level voltage signal from the B3 terminal which is an output terminal. A transmission signal in a form exceeding the period of the low level voltage signal is output. This transmission signal is given to the base of the transistor 33, and the transistor 33 is turned on periodically for a predetermined period. The collector of the transistor 33 is connected to the base electrode of the transistor 13, and the transistor 13 is periodically turned off for a predetermined period. As a result, after the transistor 21 is turned on, the current flowing through the resistor 12 is periodically turned off for a predetermined period, whereby heat generation of the resistor 12 can be suppressed.
[0024]
Further, when the vehicle engine increases to idle rotation, the AC component frequency of the one-phase power generation voltage Vac of the armature coil 4 increases due to the increase in the rotation of the rotor of the generator 1, and the F / C connected to the P terminal is increased. The output of the V converter becomes a high level voltage signal. As a result, the transistor 13 is turned off regardless of the output of the transmission circuit 31, and current consumption in the resistor 12 is completely suppressed.
[0025]
When the one-phase power generation voltage Vac further increases and the rectifier output voltage exceeds the value defined by the Zener diode 23 and the resistors 22 and 24 connected in series with each other, the transistor 25 is turned on and the switching transistor 27 is turned off. As a result, the energization of the exciting current is interrupted and the generated voltage is lowered.
[0026]
When the vehicle engine stops, the AC component frequency of the one-phase power generation voltage Vac decreases, the output of the F / V converter 29 becomes low level, and the transistor 33 and the transistor 13 are on / off controlled according to the output of the transmitter 31. When the transistor 13 is turned on, the leakage current flowing into the P terminal flows to the ground terminal via the resistor 12 and the transistor 13, the P terminal voltage becomes equal to or lower than the negative input voltage V1 of the comparator 16, and the transistor 18 is turned off. By setting the low-level voltage output period of the transmitter 31 to a value longer than the delay time determined by the capacitor 20 and the resistor 19, the transistor 21 can be reliably turned off, and the generator 1 can be turned off when the vehicle engine is stopped. The exciting coil current can be cut off reliably.
[0027]
By grounding the P terminal in this way through the bypass resistor 12 for bypassing leakage current, for example, even if leakage current is supplied from the outside to the armature winding 4 through the line 100 for detecting the one-phase generated voltage, this leakage ( Leakage) current can escape to the ground terminal through the resistor 12 and the transistor 13. As a result, it is possible to satisfactorily suppress an increase in the P terminal voltage due to leakage current flowing into the armature winding 4.
[0028]
Naturally, a voltage drop occurs at both ends of the resistor 12 due to the leakage current flowing through the resistor 12, but normally the leakage current can be considered equivalent to being connected to the line 100 through a high internal resistance. The increase in the P terminal voltage due to the current is satisfactorily suppressed by the resistor 12.
[0029]
The operation of the transmitter 31 will be described with reference to FIG. When the transmitter 31 is supplied with power from the B1 terminal and the B2 terminal voltage becomes equal to or higher than the reference voltage of the comparator 204, the output of the comparator 204, that is, the B3 terminal voltage becomes a high level voltage, and the transistor 201 connected to the B2 terminal is turned off. The capacitor 203 connected to the + input terminal of the comparator 204 is discharged by the resistor 202 connected in parallel, and the voltage gradually decreases. Further, since the transistor 207 is turned on and the reference voltage which is the negative input of the comparator 204 becomes low level, the output of the comparator 204 maintains high level voltage until the voltage of the capacitor 203 becomes low level reference voltage.
[0030]
When the voltage of the capacitor 203 becomes equal to or lower than the low level reference voltage, the output of the comparator 204, that is, the B3 terminal voltage is inverted to the low level voltage, and the negative input terminal of the comparator 204 becomes the high level reference voltage. The transistor 201 is turned on because the base current flows through the base resistor 205, and the voltage of the capacitor 203 increases rapidly. When the voltage becomes equal to or higher than the high level reference voltage, the output of the comparator 204 becomes the high level voltage again. Repeat the operation.
[0031]
With the above operation, the B3 terminal outputs a transmission waveform in which the high level voltage has a longer period than the low level voltage.
[0032]
Next, a simple circuit array of the F / V converter 29 will be described with reference to FIG. When the voltage input to the A1 terminal of the F / V converter 29 rises, a current flows into the capacitor 105 through the capacitor 101 and the diode 103. When the A1 terminal voltage decreases, the charge of the capacitor 101 flows through the diode 102. The electric charge of the capacitor 105 flows to the ground terminal through the resistor 104, and the voltage of the capacitor 105 gradually decreases. By repeating this operation, when the AC voltage frequency applied to the A1 terminal is large, the voltage of the capacitor 105 increases greatly, and the A2 terminal can output a high level voltage.
[0033]
In the excitation current control device of this embodiment described above, the comparator 16 is used to detect a slight increase in the one-phase generated voltage Vac due to residual magnetic flux, etc., turn on the transistors 21 and 27, and start excitation current energization. Since the configuration is adopted, it becomes possible to start energization of the excitation current at a low rotational speed, and the power generation rising rotational speed can be significantly reduced as compared with the conventional technique.
[0034]
[Example 2]
Another embodiment will be described below with reference to FIG.
[0035]
In this embodiment, in the excitation current control device 2 of FIG. 1, the F / V converter 29 detects the voltage converted from the AC component frequency of the one-phase generated voltage Vac by the self-excitation detection comparator 16 at its + input terminal. Further, the transmitter 31 for controlling on / off of the bypass resistor 12 has a circuit configuration that operates in response to an increase in the one-phase power generation voltage Vac.
[0036]
The rotor of the generator 1 rotates, and a one-phase generated voltage is applied from the armature coil 4 to the P terminal by the residual magnetic flux. When the AC component frequency of the one-phase generated voltage exceeds a predetermined value, the F / V converter 31 connected to the P terminal applies a voltage equal to or higher than V1 to the + terminal of the comparator 16 and outputs the output of the comparator 16 to the high level voltage. Invert. As a result, the generator 1 can energize the exciting coil 6 at a predetermined rotation speed or higher, and can supply the generator output to the battery 3.
[0037]
The output of the comparator 16 becomes a high level voltage during power generation of the generator 1, the transistor 33 is turned on, the transistor 13 is turned off, and the heat generation of the bypass resistor 12 is suppressed.
[0038]
When the rotation of the generator 1 stops, the output of the comparator 16 becomes a low level voltage, and the transistor 33 is controlled by the output of the transmitter 31 connected to the P terminal. Due to the leakage current, a voltage generated in the armature coil 4 is applied to the B2 terminal of the transmitter 31 connected to the P terminal. When this voltage exceeds a predetermined value, the transmitter 31 sends a transmission output to the transistor 33 through the resistor 32. This is applied, and the transistor 13 connected to the bypass resistor 12 is turned on and off at a predetermined cycle, and the heat generation of the bypass resistor 12 is suppressed.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an automotive alternator according to a first embodiment.
FIG. 2 is a circuit diagram showing a main part of a vehicular AC generator according to a second embodiment.
FIG. 3 is a circuit diagram showing a circuit example of a transmitter.
FIG. 4 is a circuit diagram showing a circuit example of an F / V converter.
[Explanation of symbols]
6: Excitation coil 4: Armature winding 5: Rectifier 27: Switching transistor (control unit that permits energization of excitation current)
12: Resistance (resistance value variable means)
13: Transistor (resistance value variable means)

Claims (3)

A rotor having a plurality of magnetic poles, a field winding for magnetizing the magnetic poles, an armature coaxially arranged with the rotor and wound with an electric winding, and an output voltage of the armature winding is rectified In a voltage control device for a vehicle alternator that is equipped with a rectifier that stores power in a vehicle-mounted power storage means and controls the output voltage obtained by the rectification,
The voltage controller is
When the output voltage of the armature winding exceeds a predetermined voltage threshold, or when the frequency of the output voltage of the armature winding exceeds a predetermined frequency threshold, excitation to the field winding Means for allowing energization of current;
A resistance value variable means connected between the output end of the previous armature winding and a predetermined constant potential end, the resistance value increasing means after the energization permission by the means for allowing energization of the excitation current;
A voltage control apparatus for a vehicle alternator, comprising: 2. The voltage control apparatus for a vehicle alternator according to claim 1, wherein the resistance value varying means comprises a switching means and a resistance element. The resistance value of the resistance value varying means is
When the output voltage of the armature winding exceeds the predetermined voltage threshold or a second voltage threshold set larger than the predetermined voltage threshold, the armature winding increases for a predetermined period, and then decreases again. 3. The voltage control device for an AC generator for a vehicle according to claim 1 or 2, wherein:

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