JP4482786B2 - Voltage control device for vehicle alternator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voltage control device for an automotive alternator.
[0002]
[Prior art and problems to be solved by the invention]
It is known that a vehicular AC generator generates an AC voltage (also referred to as a residual magnetic flux AC voltage), although it is minute with rotation due to residual magnetic flux even in a state where excitation current application is stopped. US Pat. No. 5,376,766 discloses this residual magnetic flux AC voltage. It is proposed to determine the presence or absence of rotation of the rotor based on a step waveform signal formed by sampling. However, in this method, if a leakage 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 large and rotation detection becomes impossible.
[0003]
WO99 / 07064 proposes to use a window comparator having a variable threshold value for the rotation determination by the residual magnetic flux AC voltage of the AC generator. However, when the threshold value of the window comparator is made variable, there is a problem that it takes time to detect rotation.
[0004]
JP-A-3-215200 (USP 5182511, EP048436) and JP-T 8-503308 (USP 5602470, WO95 / 05606) disclose a leakage current by detecting a potential difference between two phase output terminals of an armature winding. However, there is a disadvantage that the circuit configuration becomes complicated because it is necessary to input a two-phase voltage from the armature winding to the regulator.
[0005]
Japanese Patent Laid-Open No. 3-215200 (US Pat. No. 5,182,511, EP 0408436) detects the potential difference between the two-phase output terminals of the multiphase AC voltage in a floating state, so that the reference potential setting of the comparator becomes complicated. there were.
[0006]
The present invention has been made in view of the above problems, and is capable of reliably detecting rotation with a 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 a machine.
[0007]
[Means for Solving the Problems]
  Claim 1firstThe voltage control device for an AC generator for a vehicle according to the present invention includes a rotor that has a magnetic pole and generates a rotating magnetic field, a field winding for magnetizing the magnetic pole, and an electric machine that induces an AC voltage by the rotating magnetic field. A secondary winding, a full-wave rectifier circuit that rectifies the AC voltage to charge the on-vehicle battery, a rotation detection circuit that detects the start of rotation based on the power generation voltage of the armature winding, and the energization current is controlled. And a voltage control circuit for controlling the output voltage of the full-wave rectifier.SystemIn the control device, the rotation detection circuit has a first threshold value that is higher than a negative potential of the in-vehicle battery and less than half of a nominal voltage of the in-vehicle battery, and lower than a nominal voltage of the in-vehicle battery. , A second threshold value greater than one half of the nominal voltage of the vehicle batteryA clamp switch that clamps the output end of the armature winding to a predetermined potential, the first threshold value and the output voltage of the armature winding are compared when the clamp switch is turned on, and A comparison circuit for comparing the second threshold value and the output voltage of the armature winding when the clamp switch is turned off to detect rotation of the rotor;It is characterized by that.
[0008]
  As a result, it is possible to realize a voltage control device for a vehicle alternator that can reliably detect rotation with a residual magnetic flux AC voltage while preventing the configuration from becoming complicated and the detection timing from being delayed.Furthermore, according to this configuration, when a leak current flows into the armature winding from a high potential source such as the positive electrode terminal of the rectifier, the clamp switch is turned on to discharge the leak current to It is possible to reliably detect an AC voltage (residual magnetic flux AC voltage) generated in the armature winding by the residual magnetic flux as the rotation starts, while suppressing an increase in the potential of the output terminal.
[0011]
Hereinafter, the residual magnetic flux AC voltage when the leakage current is generated will be described with reference to FIGS.
[0012]
First, FIG. 8 schematically shows a case where a leak occurs in the phase Pz other than the detection phase. The contact resistance between the output terminal Pz of the armature winding and the + B potential, for example, the positive side fin of the full-wave rectifier is defined as R1. The contact resistance value R1 is various foreign matters such as salt water, muddy water, dried crystals, and rust.
[0013]
An equivalent circuit when a leak occurs is shown in FIG. The magnitude of the leakage 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. If the resistance R2 is a very small resistance, for example, several Ω, a very large leakage current, for example, a current of several A, immediately flows to the ground via the resistance 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 pole constituting the rotor, an alternating voltage is induced due to this residual magnetization. In other words, the power supply is interposed in the leakage current path, and the AC voltage is superimposed on the DC voltage that causes the leakage, and the magnitude of the leakage current changes due to the change in 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 rotational speed of the rotor. At this time, the phase Py does not fall below the ground potential, and the voltage signal increases to the positive side in proportion to the rotor speed.
[0014]
Similarly, consider a case where the grounding resistance R2 is relatively large. For example, the resistance R2 is set to several KΩ. In this case, a very small leakage current, for example, a current of several mA flows immediately to the ground via the grounding resistor R2, and the potential of the phase Py jumps to almost the storage battery potential. Strictly speaking, it jumps to a potential determined by the voltage division ratio between the contact resistance R1 and the ground resistance R2. In this state, when the rotor of the generator rotates, an AC voltage caused by residual magnetization is superimposed on the leak-caused voltage. At this time, the phase Py does not exceed the storage battery potential, and the voltage signal increases to the lower side of the storage battery potential in proportion to the rotor speed.
[0015]
Next, consider a case where a leak occurs in the detection phase Py. Similarly, the contact resistance between the output end Py of the armature winding and the + B potential, for example, the positive side fin of the full-wave rectifier is R1.
[0016]
FIG. 12 shows an equivalent circuit when a leak occurs. The magnitude of the leakage current still depends on the state of the detection phase Py. That is, it depends on the grounding resistance R2 between the Py phase and the ground. If the resistance R2 is a very small resistance, for example, several Ω, a very large leak current, for example, a current of several A, immediately flows to the ground via the ground resistance R2, and drops the potential of the phase Py to the ground potential. Strictly speaking, the potential is fixed to a potential determined by the voltage dividing ratio of the resistor R1 and the resistor R2. In this case, since the power source (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, when the rotational speed increases and the induced voltage of the armature winding increases, the Pz phase voltage falls below the ground potential by a diode drop, and the signal current i1 flows. The leakage current and the signal current i1 flow through the resistor R2. Will flow and vary due to the voltage drop signal current of resistor R2. Eventually, in order to generate an AC signal that can be detected only by residual magnetization in the presence of a leakage current, the rotational speed needs to be sufficiently high.
[0017]
When the ground resistance R2 is relatively large (for example, several KΩ), an extremely small leakage current, for example, a current of several mA, immediately flows to the ground via the ground resistance R2, and the Py phase potential almost jumps to the storage battery potential. increase. Strictly speaking, it jumps to a potential determined by the voltage division ratio between the contact resistance R1 and the ground resistance R2. When the generator rotor 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.
[0018]
After all, even in this case, it is difficult to obtain a detectable AC signal unless the number of rotations is sufficiently high only by residual magnetization in the presence of a leakage current.
[0019]
  These problems are addressed by the claims described above.1This can be solved by the described configuration. That is, according to the present configuration, the threshold value of the comparison circuit is switched in synchronization with the on / off of the clamp switch, assuming the case where the leak current occurs and the case where the leak current does not occur. Even when it does not occur, the rotation of the rotor can be reliably detected.
[0020]
  Claim2DescriptionSecond inventionThe vehicle AC generator voltage control device ofA rotor having a magnetic pole to generate 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 rectifying the AC voltage to be mounted on a vehicle A full-wave rectifier circuit that charges the battery, a rotation detection circuit that detects the start of rotation based on the generated voltage of the armature winding, and a voltage that controls the output current of the full-wave rectifier by controlling the energization current In the control device including the control circuit, the rotation detection circuit includes a first threshold value that is higher than a negative potential of the in-vehicle battery and smaller than a half of a nominal voltage of the in-vehicle battery; A second threshold value that is lower than the nominal voltage and greater than one half of the nominal voltage of the onboard battery;The rotation detection circuit includes a clamp switch that clamps an output terminal of the armature winding to a predetermined potential, and the first threshold value and the output voltage of the armature winding when the clamp switch is turned on and off. A first comparison unit that compares both at the time, and a second comparison unit that compares the second threshold value and the output voltage of the armature winding both when the clamp switch is on and when it is off. And detecting the rotation based on the outputs of the two comparison units.
[0021]
  This,It is possible to realize a voltage control device for a vehicle alternator that can reliably detect rotation with a residual magnetic flux AC voltage while preventing the configuration from being complicated or the detection timing from being delayed. Furthermore,Clamp switch intermittentlyKawaraSince the residual magnetic flux AC voltage is always determined with two threshold values, the start of rotation can be reliably detected regardless of the operation state of the clamp switch and the presence or absence of the leakage current.
[0022]
  Claim3Claims according to the arrangement described1Or2In the vehicle alternator control device described above, a first resistor connected to the output terminal of the armature winding and the low potential terminal of the full-wave rectifier and connected in parallel to the clamp switch Since it has an element, it is possible to detect a reference stable signal and improve detection accuracy.
[0023]
  Claim4Claims according to the arrangement described1Thru3The vehicle alternator control device according to any one of the above, further connected in series with the clamp switch and disposed between the output end of the armature winding and the low potential end of the full-wave rectifier. A second resistance element is included.
[0024]
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.
[0025]
  Claim5Claims according to the arrangement described4The vehicle alternator control device described above is further characterized in that the second resistance element has a lower resistance value than the first resistance element.
[0026]
According to this configuration, the leak current can be surely released to the clamp switch side, and the rotation detection when the leak occurs can be more reliably performed.
[0027]
  Claim6According to the described configuration, claims 1 to5In the voltage control device for an AC generator for a vehicle according to any one of the above, further, when the output voltage of the armature winding exceeds a predetermined threshold value, an excitation current is applied to the field winding only for a predetermined excitation current assist period. It has an exciting current assist means for performing assist energization.
[0028]
As a result, the output voltage of the armature winding can be increased, so that even if there is a leakage current, the rotation of the rotor can be reliably and promptly detected even when the rotational speed is low.
[0029]
  Claim7Claims according to the arrangement described6The voltage control device for a vehicle AC generator described above is further characterized in that the excitation current assist means intermittently performs the excitation current assist energization during the excitation current assist period. Thereby, it is possible to realize reliable rotation detection while suppressing waste of the generated current through the clamp switch.
[0030]
  Claim8Claims according to the arrangement described6Or7In the vehicle AC generator voltage control apparatus described above, the excitation current assisting means prohibits the next excitation current assist energization for a longer time than the excitation current assist period after the excitation current assist period ends. It is characterized by.
[0031]
Thereby, the waste of a vehicle-mounted battery can be suppressed.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the voltage control apparatus for a vehicle alternator according to the present invention will be described with reference to the following examples.
[0033]
[Example 1]
The apparatus of Example 1 is demonstrated with reference to FIG. FIG. 1 is a block circuit diagram of the vehicle alternator of this embodiment.
[0034]
(overall structure)
DESCRIPTION OF SYMBOLS 1 is the alternator of this invention, 2 is a vehicle-mounted battery, 3 is the three-phase armature winding of the alternator 1, 4 is a full-wave rectifier circuit for rectifying the AC output of the armature winding 3, 5 is a field winding, A voltage control device 6 adjusts the field current to control the output voltage of the alternator 1 within a predetermined range.
[0035]
Reference numeral 61 denotes a power transistor having a high-side switch structure for intermittently supplying a field current flowing through the field winding 5, 62 a flywheel diode for allowing the field current to flow when the power transistor 61 is OFF, and 63 for full-wave rectification. A voltage control circuit for converging the output voltage of the circuit 4 within a predetermined range, 64 is a main power supply circuit for supplying power to keep the voltage control circuit 63 in an operating state, and 65 is for inputting the Y-phase output voltage Py of the armature winding 3 The sub power supply circuit generates a signal for detecting the rotation of the rotor from the Y-phase output voltage Py and driving the main power supply circuit 64.
[0036]
Since this type of voltage control device for an AC generator for a vehicle is well known except for the main power supply circuit 64 and the sub power supply circuit 65, the description other than the main power supply circuit 64 and the sub power supply circuit 65 is omitted.
[0037]
(Configuration of sub power circuit 65)
An example of the sub power supply circuit 65 will be described below with reference to the circuit diagram shown in FIG.
[0038]
Reference numeral 82 denotes a resistance element for releasing a 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.
[0039]
81 and 73 are comparators, and a first threshold voltage Vth1 higher than the negative potential of the in-vehicle battery 2 and smaller than half of the nominal voltage of the in-vehicle battery 2 is applied to the input end of the comparator 73. Has been. A second threshold voltage that is lower than the nominal voltage of the in-vehicle battery 2 and greater than half the nominal voltage of the in-vehicle battery 2 is applied to the negative input terminal of the comparator 81.
[0040]
The Y-phase output voltage Py of the armature winding 3 is applied to the + input ends of both the comparators 73 and 81, and the outputs of both the comparators 73 and 81 are sent to the counter circuit 74 through the E-OR (exclusive OR circuit) circuit 84. In response to the output of the counter circuit 74, the analog switch 75 intermittently supplies the power supply voltage to the main power supply circuit 64 in the subsequent stage.
[0041]
When there is no leakage current, the comparator 73 outputs a high level whenever 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.
[0042]
When a leak current of several mA to several + mA flows into the input terminal 71, the potential of the input terminal 71 increases to a value close to the positive electrode potential of the in-vehicle battery 2, and the potential of the input terminal 71 is rotated as shown in FIG. Then, the level is increased by the voltage drop of the resistor 82 due to the leak current, and eventually the potential of the input terminal 71 has a waveform that periodically decreases from a value close to the positive potential of the in-vehicle battery 2 due to the rotation. Therefore, when the rotation occurs, the comparator 81 outputs a low level whenever the potential of the input terminal 71 falls below the threshold voltage Vth2, and the comparator 81 outputs a pulse signal as a rotation detection signal.
[0043]
Eventually, regardless of the presence or absence of a leakage current, the comparators 73 and 81 output a pulse signal as a rotation detection signal, and this pulse signal is sent to the counter circuit 74 through an E-OR (exclusive OR circuit) circuit 84, and an analog switch 75 intermittently supplies the power supply voltage to the main power supply circuit 64 in the subsequent stage based on the output of the counter circuit 74. Details of the operation of the counter circuit 74 will be described later.
[0044]
[Example 2]
Another embodiment of the apparatus 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 changed.
[0045]
(Configuration of sub power circuit 65)
FIG. 3 is a circuit diagram of the sub power supply circuit of this embodiment.
[0046]
71 is an input terminal for inputting the Y-phase terminal voltage of the armature winding 3, and 72 is a threshold selection circuit for setting the first and second thresholds. The threshold selection circuit 72 includes voltage dividing resistors Ra, Rb, Rc, an analog switch 721, and a diode 722. The diode 722 is for preventing short-circuiting between both ends of the resistor Rb when the analog switch 721 is turned on.
[0047]
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. The second threshold voltage Vth2 is set to be larger than one half of the nominal voltage of the in-vehicle battery 2. The threshold selection circuit 72 outputs the first threshold voltage Vth1 to the comparator 73 when the analog switch 721 is opened. The first threshold voltage Vth1 is set to be smaller than half of the nominal voltage of the in-vehicle battery 2. The Y-phase output voltage Py is input to the + input terminal of the comparator 73, and either the first threshold voltage or the second threshold voltage is input to the − input terminal.
[0048]
74 is a counter circuit that counts the number of output pulses of the comparator 73, and 75 is an analog switch that supplies a power supply voltage to the main power supply circuit 64 in the subsequent stage. 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 first detector for comparing the output voltage of the Y-phase output terminal with a predetermined value. The second comparator 79 is a timer circuit that operates when the second comparator 78 is inverted. The clamp switch 76 is closed only for a predetermined period by the output signal of the timer circuit 79, and the analog switch 721 is opened. Reference numeral 80 denotes an inverter for causing the clamp switch 76 to operate in reverse to the analog switch 721 of the threshold selection circuit 72.
[0049]
(Description of operation)
The operation of the sub power supply circuit 65 shown in FIG. 3 will be described below.
[0050]
When the comparator 78 detects that the peak value of the Y-phase voltage exceeds a predetermined value, the timer circuit 79 then turns on the clamp switch 76 for a predetermined period (for example, several hundred msec), and simultaneously turns the analog switch 721 through the inverter 80. It is turned off and the threshold voltage of the first comparator 73 is set to the first threshold (low level) Vth1. This period is called a clamp period. The on-resistance of the clamp switch 76 is set to a predetermined value.
[0051]
Thereafter, when the predetermined period elapses, the timer circuit 79 turns off the clamp switch 76 and simultaneously turns on the analog switch 721 through the inverter 80 to set the threshold voltage of the first comparator 73 to the second threshold value ( High level) Vth2. This period is called a non-clamping period.
[0052]
The counter 74 includes a digital comparator (not shown). When the digital rotation value output from 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, and the analog switch 75. Turns on the main power supply circuit 64.
[0053]
(Rotation detection operation during clamp period)
The rotation detection operation during the clamp period will be described below.
[0054]
When there is no leakage current, the rotation starts, and when Py exceeds Vref, the comparator 78 is inverted and enters the clamp period. During the clamp period, the analog switch is turned off, and Vth1 is input as a threshold value to the comparator 73. When Py exceeds Vth1, a high level is output and rotation is detected.
[0055]
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 becomes equal to the leak current × the on-resistance of the clamp switch 76. Is suppressed to a small value (preferably half or less of the first threshold voltage) within a range in which the ON resistance of the clamp switch 76 is set to be small.
[0056]
Therefore, in the rotation stop state, the comparator 73 detects a low level (rotation stop). That is, when the leakage current flows into the input end 71 even when the rotor is stationary, the first comparator 73 is inverted below the predetermined leakage current value by the clamp switch 76 as described above. Therefore, the leakage current inflow is not erroneously determined as rotation.
[0057]
If the rotor is rotating, the residual magnetic flux AC voltage is input to the input end 71. Since the residual magnetic flux AC voltage, that is, the amplitude of the Y-phase output voltage Py crosses the first threshold voltage Vth1 if the rotational speed of the rotor increases to some extent, the first comparator 73 is proportional to the rotational speed of the rotor. The pulse signal having the frequency thus generated is generated, and the comparator 73 detects the rotation.
[0058]
Eventually, the comparator 73 can detect the rotation regardless of the presence or absence of a leakage current during this clamping period.
[0059]
The leakage current flowing into the armature winding 3 from the high potential line falls 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 much larger 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 leakage current of the clamp switch 76 that is turned on is small, and the rise in the potential at the input terminal 71 is smaller than the threshold voltage Vth1, and it is not erroneously detected as rotation.
[0060]
(Rotation detection operation during non-clamping period)
The sub power supply circuit 65 turns off the clamp switch 76 after the timer circuit 79 turns on the clamp switch 76 for the predetermined period (for example, several hundred msec), and turns on the analog switch 721 through the inverter 80 at the same time. The threshold voltage of the comparator 73 is set to the second threshold value (high level).
[0061]
In this state, if there is a leakage current, the current path through the clamp switch 76 is cut off simultaneously with the clamp switch 76 being turned off, so that the potential of the input terminal 71 is almost the battery voltage due to the charging of the input terminal 71 by the leakage current. To rise.
[0062]
When the rotor rotates in this state and a residual magnetic flux AC voltage is generated, the Y-phase output voltage Py varies positively and negatively with respect to the battery voltage, crosses the second threshold voltage, and the first comparator 73 Again rotation detection is performed. When the rotor is not rotating, the Y-phase output voltage Py remains stuck to a high level due to the leak current, and the first comparator 73 is not inverted, and rotation is not erroneously detected.
[0063]
Eventually, according to this embodiment, the comparator 73 performs the rotation determination based on the low level threshold value regardless of the presence or absence of the current leak, and if there is the current leak, the comparator 73 rotates based on the high level threshold value. Judgment can be made. FIG. 4 is a timing chart showing the potential state of each part in FIG.
[0064]
(Example effect)
As described above, according to the present embodiment, the clamp switch 76 having a predetermined on-resistance is intermittently connected to the potential of the one-phase voltage input terminal 71 at a predetermined timing, and the non-clamping period (however, there is a leakage current) In this case, the rotation can be detected.
[0065]
As a result, not only when there is no leakage current, but also when there is a leakage current (in fact, this case is overwhelmingly large), it is possible to reliably detect rotation because it has escaped to ground. . In addition, 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, and the practicality is excellent. Further, it is possible to eliminate the communication line that notifies the vehicle that the ignition switch is turned on, and the wiring configuration can be simplified.
[0066]
(Modification)
In the above embodiment, the peak detector 77 is calculated from the time when it detects that the potential (instantaneous value) of the input terminal 71 is larger than the threshold voltage Vref at the input terminal of the second comparator 78. The clamp switch 76 is turned on for a predetermined period set in the timer circuit 79 and the threshold voltage of the first comparator 73 is switched to the low level for non-leakage state detection. An average value may be used instead. Alternatively, the peak detector 77 may be omitted and the potential at the input terminal 71 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 long period (for example, several hundreds msec) for a predetermined period T. You may switch between the rotation detection by the threshold voltage and the rotation detection by the second threshold voltage. In this case, by setting the clamp-on period to be shorter than the clamp-off period, it is possible to reduce the loss of the generated current through the clamp switch 76 after the power generation starts.
[0067]
[Example 3]
FIG. 5 shows a third embodiment which is a modification of the second embodiment described above.
[0068]
In this modification, a third comparator 81 and an E-OR (exclusive OR circuit) circuit 84 are added in place of the threshold value selection circuit of the second embodiment, and the Y-phase output voltage Py is first set. A circuit configuration that compares the threshold voltage Vth1 and the second threshold voltage Vth2 simultaneously is employed. The basic operation is the same as in the first embodiment.
[0069]
The clamp switch 76 in FIG. 3 is replaced with a parallel resistor 82, a series resistor 83, and a clamp switch 76a in FIG. The series resistor 83 corresponds to the on-resistance of the clamp switch 76 in FIG. 1. In FIG. 3, in order to use a small on-resistance as the clamp switch 76a, the series resistor 83 is added in series with the clamp switch 76a. Of course, the series resistor 83 can be omitted by setting the on-resistance of the clamp switch 76a to an appropriate value. The parallel resistor 82 bypasses a very small level of leakage current to the ground to prevent the potential of the input terminal 71 from rising, and thus the leakage current is substantially reduced in a state where this very small leakage current flows. It can be regarded as not flowing, and is set to a fairly high value.
[0070]
The operation will be described.
[0071]
(Rotation detection operation during clamp period)
The rotation detection operation during the clamp period will be described below.
[0072]
When there is no leakage current, the comparator 73 outputs a high level every time the potential of the input terminal 71 exceeds the threshold voltage Vth1, and detects rotation.
[0073]
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 becomes equal to the leak current × the resistance value of the series resistor 83. Is suppressed to a small value (preferably half or less of the first threshold voltage) within a range in which the resistance value of the series resistor 83 is set to be small. Therefore, in the rotation stop state, the comparator 73 detects a low level (rotation stop). That is, when the leakage current flows into the input end 71 even when the rotor is stationary, the first comparator 73 is inverted below the predetermined leakage current value by the clamp switch 76 as described above. Therefore, the leakage current inflow is not erroneously determined as rotation. If the rotor is rotating, the residual magnetic flux AC voltage is input to the input end 71. Since the residual magnetic flux AC voltage, that is, the amplitude of the Y-phase output voltage Py crosses the first threshold voltage Vth1 if the rotational speed of the rotor increases to some extent, the first comparator 73 is proportional to the rotational speed of the rotor. The pulse signal having the frequency thus generated is generated, and the comparator 73 detects the rotation.
[0074]
Eventually, the comparator 73 can detect the rotation regardless of the presence or absence of a leakage current during this clamping period.
[0075]
Next, in this clamping period, the comparator 81 always outputs a low level because the threshold voltage Vth2 is high. Therefore, the E-OR circuit 84 outputs a high level only when the comparator 73 outputs a high level, and performs the rotation detection.
[0076]
(Rotation detection operation during non-clamping period)
During the non-clamping period, the comparator 73 naturally detects rotation when there is no leakage current. However, if there is a leakage current, the potential at the input terminal 71 becomes a high level, so a high level is always output and rotation cannot be detected.
[0077]
On the other hand, the comparator 81 is unclamped when there is a leak current, so the Py potential is at a high potential, and when the rotation starts and falls below Vth2, a pulse is output to detect the rotation. If it is not rotating, no pulse is generated, and it can be detected that it is not rotating.
[0078]
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 leakage current, the other outputs a high level, and the other outputs a high level when there is a leakage current. And the other outputs a pulse signal. As a result, the E-OR circuit can output a pulse signal during rotation in both the clamping period and the non-clamping period.
[0079]
Also in this embodiment, the on-period of the clamp switch 760 can be relatively shortened compared to the non-clamp period, and the output loss after the power generation rises can be reduced.
[0080]
Further, when 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.
[0081]
(Modification)
In addition, it is possible to energize the field winding 5 in a predetermined period that overlaps the ON period of the clamp switch 76 based on the output signal of the peak detector 77, so that the detection sensitivity can be improved.
[0082]
In this case, the rotor is not rotating, and as the Y-phase output voltage Py rises due to the leakage current, the second comparator 78 is inverted to start energizing excitation current, and the energizing current energization is started after a predetermined period. When the process is completed, if there is a leak current, the battery continues to enter the excitation current energization mode, which may lead to battery waste. In order to prevent this, if a predetermined pause time sufficiently longer than this predetermined period is set, and energization of the excitation current is prohibited during the pause period immediately after the excitation current energization is completed, battery waste is suppressed. be able to.
[0083]
[Example 4]
The apparatus of Example 4 is demonstrated 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.
[0084]
That is, the pulse generator 91 generates a pulse signal voltage having a predetermined duty ratio during a predetermined period in which the comparator 78 described in the second embodiment detects rotation and closes the clamp switch 76 determined by the timer circuit 79. Then, the power transistor 61 is operated through the OR circuit 92 and energization with the predetermined duty ratio is performed.
[0085]
As a result, the power generation voltage can be increased by assisting energization of the field winding 5 with the excitation current immediately after the rotation is detected, so that the signal detection accuracy can be improved.
[0086]
[Example 5]
The apparatus of Example 5 is demonstrated 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.
[0087]
That is, if the comparator 78 described in the third embodiment temporarily detects rotation, the pulse generator 91 generates a pulse signal voltage having a predetermined duty ratio for a predetermined period determined by the second timer circuit 93 to generate an OR circuit 92. Then, the power transistor 61 is operated to energize the exciting current with the predetermined duty ratio.
[0088]
As a result, the power generation voltage can be increased by assisting energization of the exciting current to the field winding 5 immediately after the rotation is detected, so that the signal detection accuracy can be improved.
[0089]
In this embodiment, after the rotation is detected by the comparator 78, the period in which the second timer circuit 93 commands assisting the excitation current is set longer than the period in which the first timer circuit turns on the clamp switch 76a. Has been.
[0090]
As a result, the comparator 73 can perform detection when the clamp switch 76a is turned on and the excitation current assist state, and thereafter, the comparator 81 can perform detection when the clamp switch 76a is turned off and the excitation current assist state. At the time of occurrence, the comparators 73 and 81 can sequentially output pulse signals, and the detection accuracy can be improved.
[0091]
In the fourth and fifth embodiments described above, the excitation current assist occurs even when the leakage current increases, but the period (excitation current assist period) is a predetermined short time determined by the timer 79 or 93. It will not last.
[0092]
[Modification]
In the timer circuit 79 of FIG. 6 or the timer circuit 93 of FIG. 7 for explaining the above-described fourth embodiment, after the excitation current assist period ends, the next excitation current assist is performed for a longer period of time than the excitation current assist period. A function for setting an excitation current assist prohibition period for prohibiting the start of the period can be provided.
[0093]
Thereby, current waste due to energization of excitation current can be suppressed.
[0094]
This type of timer function is well known and can be easily realized by software, and the circuit configuration of the timer circuit is not shown.
[0095]
[Modification]
In each of the above-described embodiments, a vehicle AC having a field winding rotary synchronous generator configuration that generates a rotating magnetic field by supplying a field current to a field winding wound around a rotor through a brush and a slip ring. Although the case where the present invention is applied to a generator has been described, the present invention can also be applied to a field winding fixed synchronous generator configuration in which a field winding is wound around a stator core.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a configuration of the present invention.
FIG. 2 is a circuit diagram illustrating a sub power supply circuit according to the first embodiment.
FIG. 3 is a circuit diagram illustrating 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 illustrating a sub power supply circuit according to a third embodiment.
FIG. 6 is a circuit diagram illustrating a sub power supply circuit according to a fourth embodiment.
7 is a circuit diagram showing a modification of the fifth embodiment. FIG.
FIG. 8 is a schematic explanatory diagram showing a signal generation state when a conventional leakage current is generated.
FIG. 9 is a schematic explanatory diagram illustrating a signal generation state when a conventional leakage current is generated.
FIG. 10 is a schematic explanatory diagram illustrating a signal generation state when a conventional leakage current is generated.
FIG. 11 is a schematic explanatory diagram illustrating a signal generation state when a conventional leakage current is generated.
FIG. 12 is a schematic explanatory diagram showing a signal generation state when a conventional leakage current is generated.
FIG. 13 is a schematic explanatory diagram illustrating a signal generation state when a conventional leakage current is generated.
FIG. 14 is a schematic explanatory diagram illustrating a signal generation state when a conventional leakage current is generated.
[Explanation of symbols]
1 Vehicle generator
3 Armature winding
5 Field winding
6 Voltage controller
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

Claims (8)

A rotor having a magnetic pole to generate 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 rectifying the AC voltage to be mounted on a vehicle A full-wave rectifier circuit that charges the battery, a rotation detection circuit that detects the start of rotation based on the generated voltage of the armature winding, and a voltage that controls the output current of the full-wave rectifier by controlling the energization current in Ru control device and a control circuit,
The rotation detection circuit includes:
A first threshold value that is higher than the negative potential of the in-vehicle battery and less than one half of the nominal voltage of the in-vehicle battery; and less than a nominal voltage of the in-vehicle battery; a second threshold value greater than 1,
A clamp switch for clamping the output end of the armature winding to a predetermined potential;
The first threshold value and the output voltage of the armature winding are compared when the clamp switch is turned on, and the second threshold value and the output voltage of the armature winding are compared with the clamp switch. A comparison circuit for detecting the rotation of the rotor as compared to when the motor is off;
Voltage control apparatus for a vehicle alternator, characterized in that it comprises a. A rotor having a magnetic pole to generate 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 rectifying the AC voltage to be mounted on a vehicle A full-wave rectifier circuit that charges the battery, a rotation detection circuit that detects the start of rotation based on the generated voltage of the armature winding, and a voltage that controls the output current of the full-wave rectifier by controlling the energization current In a control device comprising a control circuit,
The rotation detection circuit includes:
A first threshold value that is higher than the negative potential of the in-vehicle battery and less than one half of the nominal voltage of the in-vehicle battery; and less than a nominal voltage of the in-vehicle battery; A second threshold value greater than 1,
Furthermore, a clamp switch for clamping the output end of the armature winding to a predetermined potential;
A first comparison unit that compares the first threshold value and the output voltage of the armature winding both when the clamp switch is on and when it is off;
A second comparison unit that compares the second threshold value and the output voltage of the armature winding both when the clamp switch is on and when it is off;
A voltage control device for an AC generator for a vehicle, wherein rotation is detected based on outputs of both the comparison units. Thereby connecting the low potential end of the full-wave rectifier device and the output terminal of the armature winding, according to claim 1, characterized in that have a first resistance element connected in parallel with the clamp switch or 3. The voltage control device for an AC generator for a vehicle according to 2 . 1 to claim characterized by having a second resistance element disposed between the connected to the clamp switch in series with the low potential end of the full-wave rectifier device and the output terminal of the armature winding 4. The voltage control device for a vehicle alternator according to any one of 3 above. 5. The voltage control device for an automotive alternator according to claim 4, wherein the second resistance element has a lower resistance value than the first resistance element . Excitation current assist means for carrying out excitation current assist energization to the field winding for a predetermined excitation current assist period when the output voltage of the armature winding exceeds a predetermined threshold value. The voltage control apparatus of the alternating current generator for vehicles in any one of Claims 1 thru | or 5 . The excitation current assisting means, the excitation current assisting period to the excitation current vehicular alternator voltage control apparatus according to claim 6, wherein the assist current is characterized that you intermittently performed. 8. The vehicle AC according to claim 6, wherein the excitation current assist means prohibits the next excitation current assist energization for a longer time than the excitation current assist period after the excitation current assist period ends. Generator voltage control device.

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