JP2003033095A - Voltage controller for on-vehicle ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage controller for on-vehicle AC generator that can detect the output voltage signal of the armature winding of an on-vehicle AC generator by distinguishing the true signal from noise caused by a leakage current even when the leakage current occurs in the armature winding. SOLUTION: This voltage controller is provided with a comparator circuit 73 which has a first threshold smaller than the 1/2 of the nominal voltage of an on-vehicle electricity storing means and a second threshold larger than the 1/2 of the nominal voltage of the electricity storing means, and compares the one-phase output voltage of the armature winding with the first and second thresholds. The controller detects the rotation of the rotor of the AC generator upon detecting that the count value of the output pulse of the comparator circuit 73 exceeds a prescribed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage control device for a vehicle alternator.

[0002]

2. Description of the Related Art An AC generator for a vehicle may generate an AC voltage (also called a residual magnetic flux AC voltage) although it is minute with rotation due to residual magnetic flux even when the excitation current is not supplied. Known and USP
No. 5,376,876 proposes to determine whether or not the rotor is rotating based on a step waveform signal formed by sampling the residual magnetic flux AC voltage. However, in this method, when a leak current flows from the high potential line into the armature winding and a voltage drop occurs in the armature winding, a DC voltage is superimposed on the residual magnetic flux AC voltage. The waveform signal becomes so large that rotation cannot be detected.

WO99 / 07064 proposes to use a variable threshold window comparator for rotation determination by the residual magnetic flux AC voltage of an AC generator. However, when the threshold value of the window comparator is made variable, there is a problem that it takes time to detect the rotation.

JP-A-3-215200 (USP5182)
511, EP 048436) publication and special table No. 8-503.
308 (USP5602470, WO95 / 0560)
Although the 6) publication proposes to reduce the influence of the leak current by detecting the potential difference between the two-phase output terminals of the armature winding, the regulator of the two-phase voltage from the armature winding is proposed. However, it has a drawback that the circuit configuration becomes complicated.

Further, Japanese Patent Laid-Open No. 3-215200 (USP5
182511, EP 0408436), there is a problem that the reference potential setting of the comparator becomes complicated because the potential difference between the output terminals of the two phases of the multi-phase AC voltage is detected in the floating state.

The present invention has been made in view of the above-mentioned problems, and it is possible to reliably detect the rotation by the residual magnetic flux AC voltage while preventing the configuration from being complicated and the detection timing from being delayed. It is an object of the present invention to provide a voltage control device for an alternator for a vehicle.

[0007]

According to a first aspect of the present invention, there is provided a voltage control device for an automotive alternator according to the present invention. The rotor has a magnetic pole to generate a rotating magnetic field, and the magnetic pole is magnetized. Based on a field winding, an armature winding that induces an AC voltage by the rotating magnetic field, a full-wave rectifier circuit that rectifies the AC voltage to charge a vehicle battery, and a generated voltage of the armature winding In the control device including a rotation detection circuit that detects the start of rotation and a voltage control circuit that controls the energizing current to control the output voltage of the full-wave rectifier, the rotation detection circuit is a negative electrode of the vehicle battery. Higher than the potential,
A first threshold value that is less than half the nominal voltage of the vehicle battery and a second threshold value that is lower than the nominal voltage of the vehicle battery and greater than half the nominal voltage of the vehicle battery. A threshold value, and compares the output voltage of the armature winding with any one of the threshold values.

Thus, it is possible to realize a voltage control device for a vehicle alternator capable of surely detecting rotation by the residual magnetic flux AC voltage while preventing the structure from being complicated and delaying the detection timing. You can

According to a second aspect of the present invention, in the voltage control device for a vehicle AC generator according to the first aspect, the rotation detection circuit further includes a clamp switch for clamping the output end of the armature winding at a predetermined potential. , Comparing the first threshold value and the output voltage of the armature winding when the clamp switch is turned on, and the second threshold value and the output voltage of the armature winding are clamped. And a comparator circuit for detecting the rotation of the rotor as compared with when the switch is off.

According to this structure, when a leak current flows into the armature winding from a high potential source such as the positive terminal of the rectifier, the clamp switch is turned on to discharge the leak current to discharge the armature winding. It is possible to reliably detect the AC voltage (residual magnetic flux AC voltage) generated in the armature winding due to the residual magnetic flux at the start of rotation while suppressing the increase in the potential at the output end of the wire.

The residual magnetic flux AC voltage when a leak current is generated will be described below with reference to FIGS.

First, FIG. 8 schematically shows a case where a leak occurs in the phase Pz other than the detection phase. Output terminal P of armature winding
Let R1 be the contact resistance between z and the + B potential, for example, the fin on the positive electrode side of the full-wave rectifier. The contact resistance value R1 is various foreign substances such as salt water, muddy water, dried crystals thereof, and rust.

FIG. 9 shows an equivalent circuit when a leak occurs. The magnitude of the leak current depends on the state of the detection phase Py. That is, it depends on the ground resistance R2 between the phase Py and the ground. Resistance R2
Is an extremely small resistance, for example, several Ω, an extremely large leakage current, for example, a current of several A, immediately flows into the ground through the resistor R2 and drops the potential of the phase Py to the ground potential. When the rotor of the generator rotates in this state, since the magnetization at the previous power generation remains in the field poles that form the rotor, an AC voltage due to this residual magnetization is induced. That is, the power supply is interposed in the leak current path, and the AC voltage is superimposed on the DC voltage that causes the leak, and the magnitude of the leak current changes due to the change of the AC voltage and the voltage drop of the resistor R2 changes. Then, the AC voltage component is superimposed on the Py-phase voltage. The amplitude of this voltage increases in proportion to the rotation speed of the rotor. At this time, the phase Py never becomes lower than the ground potential, and the voltage signal increases to the positive side in proportion to the rotor speed.

Similarly, consider the case where the ground resistance R2 is relatively large. For example, the resistance R2 is several KΩ. In this case, an extremely small leak current, for example, a current of several mA, immediately flows into the ground through the ground resistance R2, and the potential of the phase Py is almost jumped to the storage battery potential. Strictly speaking, contact resistance R1
And the potential jumps to a potential determined by the voltage division ratio of the ground resistance R2. When the rotor of the generator rotates in this state, the AC voltage caused by the residual magnetization is also superposed on the leak voltage. At this time, the phase Py never exceeds the storage battery potential, and the voltage signal increases in proportion to the rotor speed to the lower side than the storage battery potential.

Next, consider a case where a leak occurs in the detection phase Py. Similarly, the contact resistance between the output terminal Py of the armature winding and the + B potential, for example, the positive-side fin of the full-wave rectifier is R1.
And

FIG. 12 shows an equivalent circuit when a leak occurs.
The magnitude of the leak current still depends on the state of the detection phase Py. That is, it depends on the ground resistance R2 between the Py phase and the ground.
If the resistance R2 is an extremely small resistance, for example, several Ω, an extremely large leak current, for example, a current of several A immediately flows into the ground through the ground resistance R2, and the potential of the phase Py drops to the ground potential. Strictly speaking, it is fixed to a potential determined by the voltage division ratio of the resistors R1 and R2. In this case, since the power supply (armature winding) does not intervene in the path of the leakage current, the magnitude of the leakage current does not depend on the armature induced voltage, and therefore the potential of the phase Py does not change even when the rotor rotates. However, if the rotation speed increases and the induced voltage in the armature winding increases, P
The z-phase voltage is lower than the ground potential by a diode drop, the signal current i1 flows, the leak current and the signal current i1 flow in the resistor R2, and the fluctuation occurs due to the voltage drop signal current of the resistor R2. To do. After all, in order to generate an AC signal which can be detected only by the residual magnetization in the presence of the leak current, the rotation speed needs to be sufficiently high.

When the ground resistance R2 is relatively large (for example, several KΩ), an extremely small leak current, for example, a current of several mA, immediately flows into the ground through the ground resistance R2, and the Py-phase potential is almost stored in the storage battery. Jump to potential. Strictly speaking, the voltage jumps to a potential determined by the voltage division ratio of the contact resistance R1 and the ground resistance R2. When the rotor of the generator rotates in this state, the signal current i2 does not flow unless the potential of the phase Pz exceeds the potential of the storage battery by a diode drop.

After all, even in this case, in the presence of the leak current, it is difficult to obtain an AC signal that can be detected unless the rotation speed becomes sufficiently high only by the residual magnetization.

These problems can be solved by the structure described in claim 2. That is, according to this configuration, the threshold value of the comparison circuit is switched in synchronism with the on / off state of the clamp switch, assuming that a leak current is generated and not generated. Even if it does not occur, the rotation of the rotor can be reliably detected.

According to a third aspect of the present invention, in the voltage control device for a vehicle AC generator according to the first aspect, the rotation detection circuit further includes a clamp switch for clamping the output end of the armature winding at a predetermined potential. A first comparing section that compares the first threshold value and an output voltage of the armature winding both when the clamp switch is on and when the clamp switch is off; and the second threshold value and the armature. It is characterized in that it has a second comparing section for comparing the output voltage of the winding with both the ON and OFF states of the clamp switch, and detects the rotation based on the outputs of both comparing sections.

According to this structure, the residual magnetic flux AC voltage is always judged by the two threshold values regardless of the intermittent operation of the clamp switch. It is possible to reliably detect the start of rotation regardless of the presence or absence of.

According to the structure described in claim 4, in the control device for the vehicle alternator according to claim 2 or 3, the output terminal of the armature winding and the low potential terminal of the full-wave rectifier are further connected. Since the first resistance element is connected and is connected in parallel with the clamp switch, a stable reference signal is detected, and the detection accuracy can be improved.

According to a fifth aspect of the present invention, in the control device for the vehicle alternator according to any of the second to fourth aspects, the output terminal of the armature winding is further connected in series with the clamp switch. And a second resistance element disposed between the full-wave rectifier and the low potential end.

According to this structure, the leak current discharged through the clamp switch can be suppressed, and the safety and life of the clamp switch can be improved.

According to the structure described in claim 6, in the control device for the vehicle alternator according to claim 5, further, the second
Of the first resistance element has a resistance value lower than that of the first resistance element.

According to this structure, the leak current can be surely released to the clamp switch side, and the rotation detection when the leak occurs can be more surely performed.

According to the configuration of claim 7, in the voltage control device for an automotive alternator according to any one of claims 1 to 6, the output voltage of the armature winding further exceeds a predetermined threshold value. In this case, there is provided an exciting current assisting means for carrying out exciting current assist energization to the field winding for a predetermined exciting current assist period.

As a result, since the output voltage of the armature winding can be increased, the rotation of the rotor can be detected reliably and promptly even in the presence of the leak current even when the rotation speed is low. .

According to the structure described in claim 8, in the voltage control device for an automotive alternator according to claim 7, the exciting current assisting means intermittently carries out the exciting current assisting during the exciting current assisting period. It is characterized by doing. As a result, it is possible to realize reliable rotation detection while suppressing the waste of the generated current through the clamp switch.

According to a ninth aspect of the present invention, in the voltage control device for an automotive alternator according to the seventh or eighth aspect, the exciting current assisting means further comprises the exciting current assisting means after the exciting current assisting period ends. The feature is that the next exciting current assist energization is prohibited for a time longer than the assist period.

As a result, it is possible to suppress the waste of the on-vehicle battery.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a voltage control device for an automotive alternator according to the present invention will be described with reference to the following examples.

[0033]

Example 1 The apparatus of Example 1 will be described with reference to FIG. FIG. 1 is a block circuit diagram of a vehicle AC generator of this embodiment.

(Overall Structure) 1 is the alternator of the present invention,
Reference numeral 2 is a vehicle battery, 3 is a three-phase armature winding of the alternator 1, 4 is a full-wave rectifier circuit that rectifies the AC output of the armature winding 3, 5 is a field winding, and 6 is a field current. The voltage control device controls the output voltage of the alternator 1 within a predetermined range.

Reference numeral 61 is a power transistor having a high side switch structure for connecting and disconnecting a field current flowing through the field winding 5.
Is a flywheel diode for passing a field current when the power transistor 61 is off, and 63 is a full-wave rectifier circuit 4.
A voltage control circuit that converges the output voltage of the device within a predetermined range,
Reference numeral 64 is a main power supply circuit that supplies power to keep the voltage control circuit 63 in an operating state, and 65 is input with the Y-phase output voltage Py of the armature winding 3, and detects the rotation of the rotor from the Y-phase output voltage Py. It is a sub power supply circuit that issues a signal for driving the main power supply circuit 64.

Since this type of voltage control apparatus for a vehicle AC generator is well known except for the main power supply circuit 64 and the sub power supply circuit 65, description of the parts other than the main power supply circuit 64 and the sub power supply circuit 65 will be omitted.

(Structure of Sub Power Supply Circuit 65) Sub Power Supply Circuit 65
An example will be described below with reference to the circuit diagram shown in FIG.

Reference numeral 82 is a resistance element for releasing the leak current flowing into the input terminal of the sub power supply circuit 65 to the ground, and has a resistance value of, for example, several k ohms.

Reference numerals 81 and 73 are comparators, and a first threshold voltage higher than the negative potential of the vehicle-mounted battery 2 and smaller than half the nominal voltage of the vehicle-mounted battery 2 is applied to the negative input terminal of the comparator 73. Vth1 is applied. A second threshold voltage, which is lower than the nominal voltage of the vehicle-mounted battery 2 and larger than half the nominal voltage of the vehicle-mounted battery 2, is applied to the negative input terminal of the comparator 81.

The Y-phase output voltage Py of the armature winding 3 is applied to the + input terminals of both comparators 73 and 81, and the outputs of both comparators 73 and 81 are countered through an E-OR (exclusive OR circuit) circuit 84. The analog switch 75 is sent to the circuit 74, and the output of the counter circuit 74 causes the analog switch 75 to
The supply of power supply voltage to the main power supply circuit 64 in the subsequent stage is interrupted.

When there is no leak current, the comparator 73 outputs a high level each time the potential of the input terminal 71 exceeds the threshold voltage Vth1, and the comparator 73 outputs a pulse signal as a rotation detection signal.

A leak current of several mA to several + mA is input terminal 7
1, the potential of the input terminal 71 increases to a value close to the positive electrode potential of the vehicle-mounted battery 2, and the potential of the input terminal 71 increases by the amount of the voltage drop of the resistor 82 due to this leakage current as shown in FIG. Only the level is raised, and eventually, the rotation causes the waveform of the potential of the input terminal 71 to periodically drop from a value close to the positive potential of the vehicle-mounted battery 2. Therefore, the comparator 81 has the input terminal 71 when the rotation occurs.
A low level is output every time the electric potential of is lower than the threshold voltage Vth2, and the comparator 81 outputs a pulse signal as a rotation detection signal.

Eventually, the comparators 73 and 81 output pulse signals as rotation detection signals regardless of the presence or absence of leak current, and the pulse signals are sent to the counter circuit 74 through the E-OR (exclusive OR circuit) circuit 84. The analog switch 75 interrupts the supply of the power supply voltage to the main power supply circuit 64 in the subsequent stage based on the output of the counter circuit 74. The details of the operation of the counter circuit 74 will be described later.

[0044]

Second Embodiment Another embodiment of the device of the present invention will be described below. In this embodiment, the circuit of the sub power supply circuit 65 shown in FIG. 1 is modified.

(Structure of Sub Power Supply Circuit 65) FIG. 3 is a circuit diagram of the sub power supply circuit of this embodiment.

Reference numeral 71 is an input terminal for inputting the Y-phase terminal voltage of the armature winding 3, and reference numeral 72 is a threshold value selecting circuit for setting the first and second threshold values. The threshold selection circuit 72 is
Voltage dividing resistors Ra, Rb, Rc, analog switch 721,
It is composed of a diode 722. Diode 722
Is for preventing a short circuit across the resistor Rb when the analog switch 721 is turned on.

When the analog switch 721 is closed, the threshold selection circuit 72 outputs the potential at the connection point of the voltage dividing resistors Ra and Rb, that is, the second threshold voltage Vth2 to the first comparator 73. Second threshold voltage Vth
2 is set to be larger than ½ of the nominal voltage of the vehicle-mounted battery 2. When the analog switch 721 is opened, the threshold selection circuit 72 has a first threshold voltage Vth1.
Is output to the comparator 73. First threshold voltage V
th1 is set to be smaller than one half of the nominal voltage of the vehicle-mounted battery 2. Y is connected to the + input terminal of the comparator 73.
The phase output voltage Py is input to the input terminal of either the first threshold voltage or the second threshold voltage.

Reference numeral 74 is a counter circuit for counting the number of output pulses of the comparator 73, and 75 is the main power supply circuit 6 in the subsequent stage.
4 is an analog switch that supplies a power supply voltage to the switch 4. 76
Is a clamp switch for grounding the Y-phase output terminal of the armature winding 3, 77 is a peak detector for detecting the peak value of the Y-phase output voltage Py, and 78 is a second for comparing the output voltage of the Y-phase output terminal with a predetermined value. , 79 is a timer circuit that operates when the second comparator 78 is inverted, and the clamp switch 76 is closed and the analog switch 721 is opened only for a predetermined period by the output signal of the timer circuit 79.
Reference numeral 80 is an inverter for causing the clamp switch 76 to operate in reverse to the analog switch 721 of the threshold selection circuit 72.

(Description of Operation) The operation of the sub power supply circuit 65 shown in FIG. 3 will be described below.

When the comparator 78 detects that the peak value of the Y-phase voltage exceeds the predetermined value, the timer circuit 79 thereafter turns on the clamp switch 76 for a predetermined period (for example, several hundred msec), and at the same time, the analog voltage is supplied through the inverter 80. The switch 721 is turned off, and the first comparator 7
3 threshold voltage to the first threshold (low level) Vt
Set to h1. This period is called a clamp period. The ON resistance of the clamp switch 76 is set to a predetermined value.

After that, when the above-mentioned predetermined period has passed, the timer circuit 79 turns off the clamp switch 76, simultaneously turns on the analog switch 721 through the inverter 80, and sets the threshold voltage of the first comparator 73 to the second threshold voltage. Set to the threshold value (high level) Vth2. This period is called a non-clamp period.

The counter 74 includes a digital comparator (not shown). When the digital rotation value output by the counter 74 is larger than the set rotation value of the digital comparator, the digital comparator outputs a high level voltage to the analog switch 75, Analog switch 7
5 turns on the main power supply circuit 64.

(Rotation Detection Operation During Clamping Period) The rotation detection operation during the clamping period will be described below.

When there is no leak current, rotation is started and
When Py exceeds Vref, the comparator 78 is inverted and the clamp period starts. During the clamp period, the analog switch is off, Vth1 is input to the comparator 73 as a threshold value, and a high level is output every time Py exceeds Vth1 to detect rotation.

When a leak current flows into the input end 71, this leak current flows to the ground through the clamp switch 76, and the average potential of the input end 71 is the leak current ×
It becomes equal to the ON resistance of the clamp switch 76, and is suppressed to a small value (preferably less than half of the first threshold voltage) within a range where the leak current is small and the ON resistance of the clamp switch 76 is set small.

Therefore, in the rotation stopped state, the comparator 73 detects a low level (rotation stopped). That is, although the rotor is stationary, the leakage current is
In the case of flowing into 1, the clamp switch 76 clamps the first comparator 73 not to invert at a predetermined leak current value or less, and thus the leak current inflow is not erroneously determined as rotation as described above.

When the rotor is rotating, the residual magnetic flux AC voltage is input to the input terminal 71. This residual magnetic flux AC voltage, that is, the amplitude of the Y-phase output voltage Py intersects with the first threshold voltage Vth1 when the rotation speed of the rotor increases to some extent, so that the first comparator 73 is proportional to the rotation speed of the rotor. Generates a pulse signal with the specified frequency, and the comparator 7
3 detects rotation.

After all, the comparator 73 can detect the rotation regardless of the presence / absence of the leak current during this clamp period.

The leak current flowing into the armature winding 3 from the high potential line drops to the ground through the above (wiring resistance + armature winding resistance) and the ON resistance of the clamp switch 76. Since the internal resistance of the leakage path between the high potential line and the armature winding 3 is significantly higher than the ON resistance of the clamp switch 76, the leakage current hardly increases when the clamp switch 76 is turned on. Therefore, the voltage drop due to the leak current of the clamp switch 76 which is turned on is small, and the increase in the potential of the input terminal 71 due to the leak voltage is smaller than the threshold voltage Vth1, and the rotation is not erroneously detected.

(Rotation Detecting Operation in Non-Clamping Period) The sub-power supply circuit 65 operates after the timer circuit 79 turns on the clamp switch 76 for the predetermined period (for example, several hundred msec).
The clamp switch 76 is turned off, and at the same time, the inverter 80
The analog switch 721 is turned on to set the threshold voltage of the first comparator 73 to the second threshold (high level).

In this state, if there is a leak current,
Since the current path through the clamp switch 76 is cut off at the same time when the clamp switch 76 is turned off, the potential of the input end 71 rises to almost the battery voltage due to the charging of the input end 71 by the leak current.

When the rotor rotates in this state and a residual magnetic flux AC voltage is generated, the Y-phase output voltage Py fluctuates positively and negatively with respect to the battery voltage and crosses the second threshold voltage,
The first comparator 73 also detects rotation. When the rotor is not rotating, the Y-phase output voltage P
The leakage current keeps y attached to a high level, the first comparator 73 does not invert, and rotation is not erroneously detected.

After all, according to this embodiment, regardless of whether or not there is the above-mentioned current leak, the comparator 73 determines the rotation based on the low-level threshold, and when there is the above-mentioned current leak, the high-level threshold is determined. The rotation determination can be performed based on the value. FIG. 4 is a timing chart showing the potential state of each part of FIG.

(Effects of Embodiment) As described above, according to the present embodiment, the potential of the one-phase voltage input terminal 71 is intermittently connected to the clamp switch 76 having a predetermined ON resistance at a predetermined timing, and is not kept in the clamp period. The rotation can be detected even during the clamp period (when there is a leak current).

As a result, not only when there is no leak current but also when there is a leak current (actually, this case is overwhelmingly large), the rotation is reliably detected because it escapes to the ground. be able to. Moreover, since the clamp switch is not always turned on, the problem that the armature current is bypassed to the ground and lost after power generation is started can be improved, which is excellent in practicality. Further, the communication line from the vehicle side for notifying that the ignition switch is turned on can be eliminated, and the wiring configuration can be simplified.

(Modification) In the above embodiment, the peak detector 77 has a potential (instantaneous value) at the input terminal 71 of the second comparator 78 that is equal to the threshold voltage Vre at the input terminal.
From the time when it is detected that it becomes larger than f, the clamp switch 76 is turned on for a predetermined period set in the timer circuit 79, and the first comparator 7
Although the threshold voltage of No. 3 is switched to the low level for detecting the non-leakage state, the average value may be used instead of the instantaneous value. Further, the peak detector 77 is omitted and the input end 7 is omitted.
The potential of 1 may be directly input to the input terminal of the second comparator. Further, the peak detector 77 and the second comparator 78 are omitted, and the timer circuit 79 is changed to an astable multivibrator that is turned on every predetermined period T for a long time (for example, several hundred msec), and the first oscillator is changed every period T. The rotation detection with the threshold voltage and the rotation detection with the second threshold voltage may be switched. In this case, by setting the clamp-on period shorter than the clamp-off period, it is possible to reduce the loss of the generated current through the clamp switch 76 after the start of power generation.

[0067]

Third Embodiment FIG. 5 shows a third embodiment which is a modification of the above-described second embodiment.

In this modification, the threshold value selecting circuit of the second embodiment is replaced by a third comparator 81 and an E-OR.
(Exclusive OR circuit) circuit 84 is added to set the Y-phase output voltage Py to the first threshold voltage Vth1 and the second threshold voltage Vy.
A circuit configuration for comparing with th2 at the same time is adopted. The basic operation is the same as in the first embodiment.

The clamp switch 76 of FIG. 3 has a parallel resistor 82, a series resistor 83, and a clamp switch 76a in FIG.
Has been replaced by. The series resistor 83 corresponds to the ON resistance of the clamp switch 76 in FIG.
In order to use a clamp switch 76a having a small ON resistance, the clamp switch 76a is additionally connected in series with the clamp switch 76a. Of course, the series resistance 83 can be omitted by setting the ON resistance of the clamp switch 76a to an appropriate value. The parallel resistor 82 prevents the leak current of an extremely small level from being bypassed to the ground and prevents the potential of the input terminal 71 from rising, so that when the extremely small leak current is flowing, the leak current is substantially reduced. It is designed to be considered as not flowing,
It is set to a fairly high value.

The operation will be described.

(Rotation Detection Operation During Clamping Period) The rotation detection operation during the clamping period will be described below.

When there is no leak current, the comparator 73 outputs a high level each time the potential of the input terminal 71 exceeds the threshold voltage Vth1, and detects rotation.

When the leak current flows into the input terminal 71, the leak current flows to the ground through the clamp switch 76, and the average potential of the input terminal 71 is the leak current x
A value that is equal to the resistance value of the series resistor 83, is small in the range where the leak current is small and the resistance value of the series resistor 83 is set small (preferably less than half of the first threshold voltage).
Be restrained by. Therefore, in the rotation stopped state, the comparator 73 detects a low level (rotation stopped). That is, when the leak current flows into the input end 71 even when the rotor is stationary, as described above, the clamp switch 76 clamps the first comparator 73 so that the first comparator 73 is inverted at a predetermined leak current value or less. Therefore, the leak current inflow is not erroneously determined as rotation. If the rotor is rotating, the residual magnetic flux AC voltage is input to the input terminal 71. The amplitude of this residual magnetic flux AC voltage, that is, the Y-phase output voltage Py is
If the rotation speed of the rotor increases to some extent, the first threshold voltage Vth1 is crossed. Therefore, the first comparator 73 generates a pulse signal having a frequency proportional to the rotation speed of the rotor, and the comparator 73 rotates the rotation. To detect.

After all, the comparator 73 can detect the rotation regardless of the presence / absence of the leak current during this clamp period.

Next, during this clamp period, the comparator 81 always outputs a low level because its threshold voltage Vth2 is high. Therefore, the E-OR circuit 84 outputs the high level only when the comparator 73 outputs the high level, and performs the rotation detection.

(Rotation Detection Operation During Non-Clamping Period) During the non-clamping period, the comparator 73 naturally detects the rotation when there is no leak current. However, if there is a leak current, the potential of the input terminal 71 becomes high level,
It always outputs high level and cannot detect rotation.

On the other hand, since the comparator 81 is unclamped when there is a leak current, the Py potential is at a high potential, and when rotation starts and Vth2 is exceeded, a pulse is output and rotation is detected. If it is not rotating, no pulse is generated, and it can be detected that it is not rotating.

After all, in both the clamp period and the non-clamp period, one of the comparators 73 and 81 outputs a pulse signal when there is no leak current, and the other outputs a high level, and when there is a leak current, Outputs a high level, and the other outputs a pulse signal. as a result,
The E-OR circuit can output a pulse signal during rotation in both the clamp period and the non-clamp period.

Also in this embodiment, the ON period of the clamp switch 760 can be relatively shortened as compared with the unclamped period, and the output loss after the start of power generation can be reduced.

If the rectified value of the generated voltage is sufficiently large, a circuit that does not turn on the clamp switch can be added to further reduce the output loss.

(Modified Mode) The peak detector 77
It is also possible to energize the field winding 5 with an exciting current during a predetermined period that overlaps with the ON period of the clamp switch 76 based on the output signal of 1, and the detection sensitivity can be improved.

In this case, the rotor is not rotating and the second comparator 78 is inverted to start energizing the exciting current as the Y-phase output voltage Py rises due to the leak current. If the leakage current remains when the current supply is finished, the magnetizing current supply mode is continuously entered, which may result in waste of the battery. In order to prevent this, by setting a predetermined rest time that is sufficiently longer than this predetermined period and prohibiting the energization of the exciting current during the rest period immediately after the end of the energizing of the exciting current, the waste of the battery is suppressed. be able to.

[0083]

Fourth Embodiment The apparatus of the fourth embodiment will be described below with reference to FIG. In this embodiment, a pulse generator 91 and an OR circuit 92 are added to the sub power supply circuit 65 of the second embodiment shown in FIG.

That is, during the predetermined period in which the comparator 78 described in the second embodiment temporarily detects the rotation and closes the clamp switch 76 determined by the timer circuit 79, the pulse generator 91 keeps the pulse signal voltage of the predetermined duty ratio. Is generated and the power transistor 61 is operated through the OR circuit 92 to energize the exciting current having the predetermined duty ratio.

As a result, immediately after the rotation is detected, the exciting current is assist-energized to the field winding 5 to increase the generated voltage, so that the signal detection accuracy can be improved.

[0086]

Fifth Embodiment The apparatus of the fifth embodiment will be described below with reference to FIG. In this embodiment, a second timer circuit 93, a pulse generator 91 and an OR circuit 92 are added to the sub power supply circuit 65 of the third embodiment shown in FIG.

That is, if the comparator 78 described in the third embodiment detects rotation, the second timer circuit 93
For a predetermined period determined by the pulse generator 91, the pulse generator 91 generates a pulse signal voltage having a predetermined duty ratio to operate the power transistor 61 through the OR circuit 92, and energizes the exciting current having the predetermined duty ratio.

As a result, immediately after the rotation is detected, the exciting current is assisted to the field winding 5 to increase the generated voltage, so that the signal detection accuracy can be improved.

In this embodiment, the comparator 78
After the rotation is detected by, the period in which the second timer circuit 93 commands the assist energization of the exciting current is set longer than the period in which the first timer circuit turns on the clamp switch 76a.

As a result, the comparator 73 performs detection while the clamp switch 76a is in the turn-on state and the exciting current assist state, and thereafter, the clamp switch 76a.
When a is in the turn-off state and the exciting current assist state, the comparator 81 can perform detection, and when a leak occurs, the comparators 73 and 81 can sequentially output pulse signals, and detection accuracy can be improved.

In the fourth and fifth embodiments described above, the exciting current assist is generated even when the leak current increases, but the period (exciting current assist period) is a predetermined short time determined by the timer 79 or 93, so that it is useless. Power consumption does not continue.

[0092]

[Modification] The timer circuit 79 of FIG. 6 or the timer circuit 93 of FIG. 7 for explaining the above-described fourth embodiment is provided with the following after the end of the exciting current assist period for a period longer than the exciting current assist period. It is possible to provide a function of setting the exciting current assist prohibition period that prohibits the start of the exciting current assist period.

As a result, it is possible to suppress current waste due to energization of the exciting current.

Note that this type of timer function is well known,
Also, it is easy to realize by software,
Illustration of the circuit configuration of the timer circuit is omitted.

[0095]

[Modifications] In each of the above embodiments, a field winding rotary synchronous generator configuration in which a field current is supplied to the field winding wound around the rotor through a brush and a slip ring to generate a rotating magnetic field. Although the case where the present invention is applied to the vehicle alternator has been described, the present invention may also be applied to a fixed field winding type synchronous generator configuration in which a field winding is wound around a stator core. it can.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a configuration of the present invention.

FIG. 2 is a circuit diagram showing a sub power supply circuit according to the first embodiment.

FIG. 3 is a circuit diagram showing a sub power supply circuit according to a second embodiment.

FIG. 4 is a timing chart showing the operation of the second embodiment.

FIG. 5 is a circuit diagram showing a sub power supply circuit according to a third embodiment.

FIG. 6 is a circuit diagram showing a sub power supply circuit according to a fourth embodiment.

FIG. 7 is a circuit diagram showing a modification of the fifth embodiment.

FIG. 8 is a schematic explanatory diagram showing a signal generation state when a conventional leak current is generated.

FIG. 9 is a schematic explanatory view showing a signal generation state when a conventional leak current is generated.

FIG. 10 is a schematic explanatory diagram showing a signal generation state when a conventional leak current is generated.

FIG. 11 is a schematic explanatory diagram showing a signal generation state when a conventional leak current is generated.

FIG. 12 is a schematic explanatory diagram showing a signal generation state when a conventional leak current is generated.

FIG. 13 is a schematic explanatory view showing a signal generation state when a conventional leak current is generated.

FIG. 14 is a schematic explanatory view showing a signal generation state when a conventional leak current is generated.

[Explanation of symbols]

1 Vehicle generator 3 armature winding 5 field winding 6 Voltage control device 63 Voltage control circuit 64 main power circuit 65 Sub power circuit 71 Threshold selection circuit 73, 79, 81 comparator 74 counter circuit 76 Clamp switch

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Tanaka             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO F-term (reference) 5H590 AA01 AA02 CA07 CA23 CC01                       CC18 CC24 CC28 CD01 CE05                       DD25 DD64 DD72 EA07 EB02                       EB14 EB21 EB29 FA06 FB01                       FC21 FC22 HA02 HA27 HB06                       JA09 JB01 JB03 JB07

Claims (9)

[Claims] 1. A rotor having a magnetic pole for generating a rotating magnetic field, a field winding for magnetizing the magnetic pole, an armature winding for inducing an AC voltage by the rotating magnetic field, and the AC voltage. Full-wave rectifier circuit that rectifies
A rotation detection circuit that detects the start of rotation based on the generated voltage of the armature winding, and a voltage control circuit that controls the energizing current to control the output voltage of the full-wave rectifier, The rotation detection circuit has a first threshold value that is higher than a negative electrode potential of the vehicle-mounted battery and is smaller than one half of a nominal voltage of the vehicle-mounted battery, and is lower than a nominal voltage of the vehicle-mounted battery. A second threshold greater than one half of the nominal voltage of the armature winding and comparing the output voltage of the armature winding with either of the thresholds. Voltage control device for vehicle alternator. 2. The rotation detection circuit includes a clamp switch that clamps an output end of the armature winding at a predetermined potential, the clamp switch that clamps the first threshold value and an output voltage of the armature winding. And when the second
And a comparison circuit that detects the rotation of the rotor by comparing the threshold voltage of the armature winding with the output voltage of the armature winding when the clamp switch is off. Alternator voltage control device. 3. The rotation detection circuit includes a clamp switch that clamps an output end of the armature winding at a predetermined potential, the clamp switch that clamps the first threshold value and an output voltage of the armature winding. Comparing the second threshold value with the output voltage of the armature winding both when the clamp switch is on and when the clamp switch is on. The voltage control device for a vehicle alternator according to claim 1, further comprising: two comparison units, wherein rotation is detected based on outputs of the both comparison units. 4. An output terminal of the armature winding is connected to a low potential terminal of the full-wave rectifier, and a first resistance element is connected in parallel with the clamp switch. The control device for the vehicle alternator according to claim 2. 5. A second resistance element, which is connected in series with the clamp switch and is arranged between an output end of the armature winding and a low potential end of the full-wave rectifier. The control device for the vehicle alternator according to any one of claims 2 to 4. 6. The control device for a vehicle alternator according to claim 5, wherein the second resistance element has a resistance value lower than that of the first resistance element. 7. Exciting current assist means for carrying out exciting current assist energization to the field winding for a predetermined exciting current assist period when the output voltage of the armature winding exceeds a predetermined threshold value. The voltage control device for an AC generator for a vehicle according to any one of claims 1 to 6, characterized in that. 8. The voltage control device for a vehicle alternator according to claim 7, wherein the exciting current assisting means intermittently carries out the exciting current assisting during the exciting current assisting period. 9. The exciting current assist means prohibits the next exciting current assist energization for a longer time than the exciting current assist period after the end of the exciting current assist period. The voltage control device for the vehicle alternator described.