Electricity: single generator systems – Automatic control of generator or driving means – Voltage of generator or circuit supplied
Reexamination Certificate
2000-11-14
2002-11-26
Ponomarenko, Nicholas (Department: 2834)
Electricity: single generator systems
Automatic control of generator or driving means
Voltage of generator or circuit supplied
C322S036000
Reexamination Certificate
active
06486638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a voltage control apparatus of an alternator.
2. Description of the Related Art
Conventionally, in a voltage control apparatus for controlling a voltage generated from an alternator to a predetermined value by turning ON/OFF a voltage applied to an energizing coil of this alternator, the alternator generated voltage is adjusted in a digital manner by employing a microcomputer. Such an alternator voltage control apparatus is typically known from, for example, Japanese Laid-open Patent Application No. Hei 05-176477.
In this type of conventional alternator voltage control apparatus, when the voltage generated from the alternator is controlled to the target voltage under better response characteristic, a target energizing current corresponding to a target current generated from the alternator is calculated by using an equation established based on the power generation characteristic of the alternator. Thereafter, a predicted energizing current, which may actually flow through the energizing coil, is calculated by using an equation established based upon an electromagnetic specification of the alternator.
Then, in response to deviation between the target value of the energizing current and the prediction value thereof, the target energizing current is corrected by way of the primary lead correction based upon both the power generation characteristic and the electromagnetic characteristic of the alternator, and thereafter, the control energizing current is calculated.
Furthermore, an ON/OFF duty ratio with respect to the control energizing current determined by this calculation is read out from a table which is set in accordance with the electromagnetic specification of the alternator. Then, a voltage applied to the energizing coil is controlled based on an ON/OFF duty ratio selected from a map so as to achieve the object, i.e., voltage control.
However, the above-described conventional alternator voltage control apparatus owns the following problems:
That is, in such a case that the power generation characteristic and the electromagnetic specification of the alternator are changed, or in such a case that the presently available power generation characteristic and electromagnetic specification are adapted to other electromagnetic specification and power generation characteristic of alternators, the voltage control apparatus is required to change the ON/OFF duty tables corresponding to the control energizing currents, and the coefficients of the calculating equations for the energizing currents, every time the electromagnetic specification and the power generation characteristic of the alternator are selected. Thus, this alternator voltage control apparatus must again establish the matching conditions.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-explained problems, and therefore has an object to provide an alternator voltage control apparatus in such a case that the alternator is controlled so as to control a generated voltage thereof to a target voltage in a feedback manner, while this alternator voltage control apparatus does not need to employ a parameter and an equation, which are established based upon a power generation characteristic and also an electromagnetic specification of this alternator. That is to say, even when any change is made in the power generation characteristic and also in the electromagnetic specification of the alternator, both the parameter and the equation required in the voltage control apparatus does not need to be changed.
To achieve the above-described object, according to a first aspect of the present invention, a voltage control apparatus of an alternator is characterized by such a voltage control apparatus of an alternator, for controlling a voltage generated by the alternator to a predetermined voltage value by turning ON/OFF a voltage applied to an energizing coil of the alternator, comprising: first logic output means for comparing the voltage generated by the alternator with a target voltage to obtain a magnitude logic which is outputted as a first ON/OFF logic; and second logic output means for outputting as a second ON/OFF logic, a PWM internal output logic in which an ON-duty rate is increased/decreased based on the first ON/OFF logic by an increased/decreased amount defined by considering a time constant of the energizing coil; wherein: a logically processed result between the first ON/OFF logic and the second ON/OFF logic is used as an ON/OFF logic of a voltage application to the energizing coil.
With employment of the above-described arrangement, the alternator voltage control apparatus owns the following effect. That is, in such a case that the alternator is controlled so as to control the generated voltage thereof to the target voltage in the feedback manner, this alternator voltage control apparatus does not need to employ the parameter and the equation, which are established based upon the power generation characteristic and also the electromagnetic specification of this alternator. Also, while both the ON-duty rate of the ON/OFF logic of the voltage application to the energizing coil and the logic frequency can be stabilized within a predetermined frequency range, these ON-duty rate and the logic frequency can be set with having compatibility.
According to a second aspect of the present invention, in the first aspect of the present invention, the alternator voltage control apparatus is characterized in that the target voltage is hysteresis-corrected along a direction to hold a magnitude logic obtained by comparing the target voltage with the generated voltage of the alternator; the hysteresis correction amount is changed based on a parameter related to an alternator rotation number and an alternator output strength; and also the hysteresis correction amount is changed in a feedback manner based on an inversion period of the first ON/OFF logic.
With employment of the above-described arrangement, the alternator voltage control apparatus owns the following effect. That is, the target voltage is hysteresis-corrected in order that the once determined logic is not immediately inverted. Such a hysteresis-correction can be carried out with respect to all possible operation conditions of the alternator.
According to a third aspect of the present invention, in the first aspect of the present invention, the alternator voltage control apparatus is characterized in that the first logic output means is provided with logic inversion suppressing means by which the first ON/OFF logic is hardly inverted; a suppression strength of the logic inversion suppressing means for an ON logic to an OFF logic is made different from a suppression strength of the logic inversion suppressing means for an OFF logic to an ON logic; and the suppression strengths are changed in a feedback manner in response to a resulting logic period of the first ON/OFF logic.
With employment of the above-described arrangement, the alternator voltage control apparatus owns the following effect. That is, the target voltage is hysteresis-corrected in order that the once determined logic is not immediately inverted. Such a hysteresis-correction can be carried out with respect to all possible operation conditions of the alternator.
According to a fourth aspect of the present invention, in the first aspect of the present invention, the alternator voltage control apparatus is characterized in that the logic period of the PWM internal output which constitutes the second ON/OFF logic is changed by executing a calculation based on the parameter related to both the alternator rotation number and the alternator output strength and by retrieving a content of a table; or is changed based on the period of the first ON/OFF logic.
With employment of the above-described arrangement, the alternator voltage control apparatus owns the following effect. That is, the frequency of the first ON/OFF logic can be firmly set.
According to a fifth aspect of the present invention, in the first
Komurasaki Keiichi
Sumimoto Katsuyuki
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