JPS61293124A - Control of charge generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method of controlling a charging generator, and particularly to a method of controlling a charging generator suitable for use in automobiles and the like.

[Background of the invention]

BACKGROUND ART In charging generators for automobiles and the like, control is performed to prevent overcharging by controlling the charging voltage of a storage battery to fall within a predetermined range. Furthermore, in recent years, attempts have been made to use microcomputers to save fuel consumption and improve acceleration during rapid acceleration and deceleration. These provide a pulsed field current and make the time width of the pulse variable depending on the operating conditions (Japanese Patent Laid-Open No. 57-22338).
No., Utility Model Publication No. 1983-643). On the other hand, in a charging generator for a vehicle, as described in the May 1979 issue of Electronic Materials Magazine, page 65, it is known that a large cage voltage is generated when the full load is cut off. However, in the above-mentioned known method, since a time delay is unavoidable in the signal processing by the microcomputer, there is a possibility that the power transistor that turns on and off the field current of the charging generator may remain in a conductive state when a large energy surge occurs. Yes, there were cases where this power transistor was destroyed.

[Purpose of the invention]

An object of the present invention is to provide a method for controlling a charging generator in which power elements such as power transistors are not destroyed even when a high-energy surge is applied when the charging generator is controlled by pulse width control. There is a particular thing.

[Summary of the invention]

In addition to calculating the time average value of the storage battery voltage to be controlled and setting this as a predetermined value, the present invention also provides a detection means for detecting the instantaneous voltage of the storage battery, so that when a large instantaneous voltage is detected, The feature is that the field current is forcibly turned off.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a circuit diagram of a charging system including a generator driven by an engine (not shown). In the figure, magnetic flux is supplied to the armature winding 1 of a generator 20 by a field winding 2, and the AC output of the armature winding 1 is converted to DC by a three-phase full-wave rectifier 3. . The storage battery 4 is connected to the three-phase full-wave rectifier 3 to be charged, and supplies current to an external load (not shown) via a key switch 45. The voltage regulator 6 includes a constant voltage diode 61 and resistors 62 and 63a.

63b, 64a, 64b, 68, a comparator 65, a power transistor 66, and a flywheel diode 67. On the other hand, the control device 7 includes a central processing unit 71, a synchronization signal generation crystal oscillator 72, a parallel input register 73,
analog-to-digital converter 74, output register 75,
It is composed of a transistor 76. To this control device 7, a pulse signal 8 of the ignition system (a frequency corresponding to the engine speed is obtained), a full open switch signal 9 of the engine throttle (not shown), a brake light signal 10, and the ambient temperature of the storage battery are sent. 11 is input.

In the above configuration, when the key switch 5 is turned on, a base current flows from the storage battery 4 through the key switch 5 and the resistor 68 to the power transistor 66.
6 becomes conductive, and an exciting current flows from the storage battery 4 through the field winding 2 and the power transistor 66. Next, when the generator starts rotating, a voltage is generated in the armature winding 1, and the storage battery 4 is charged via the three-phase full-wave rectifier 3.

When the key switch 5 is turned on, the control device 7 starts operating, sequentially calculates the optimum on-duty of the transistor 76 according to the voltage of the storage battery 4 and the input signals 8 to 11, and controls the voltage of the storage battery 4. Further, a constant voltage is generated in the constant voltage diode 61 in the voltage regulator 6, and the comparator 65
is being driven. When the generator has started generating electricity, if the generated voltage or the voltage of the storage battery 4 is lower than the set voltage set in the restriction bag w7, the conduction rate of the transistor 76 is lowered, and as a result, the conduction of the power transistor 66 is reduced. The current rate increases and the field current is energized.

As the field current increases, the generated voltage also increases, and the voltage of the storage battery 4 increases. When the generated voltage or the voltage of the storage battery 4 becomes higher than the set voltage, the conduction rate of the transistor 76 is increased, and as a result, the conduction rate of the power transistor 66 is lowered, and the field current is attenuated. Then, as the field current decreases, the generated voltage drops, and the voltage of the storage battery 4 becomes low.

By repeating the above operations, the voltage of the storage battery 4 is controlled to a constant value.

In the normal voltage control state described above, the voltage at the inverting input terminal of the comparator 65 is always lower than the voltage at the non-inverting input terminal obtained by dividing the voltage of the voltage regulator diode 61, and the output of the comparator 65 is at a high level. , transistor 6
6 is conductive whenever transistor 76 is not conductive.

In this state, the control device 7 further calculates the optimum on-duty of the transistor 66, using the following method, for example.

The pulse period of the pulse signal 8 of the ignition system is counted by an internal clock, and the engine adjustment state is calculated based on the temporal change in the period. When sudden acceleration is detected at a certain detection level or when the engine throttle fully open switch signal 9 is detected, the freewheeling rate of the transistor 76 is increased to reduce the field current and armature current. As a result, the mechanical drive torque of the generator is reduced, and the acceleration performance of the engine is improved. On the other hand, when a deceleration state of the engine is detected due to a change in the period of the pulse signal 8 of the ignition system, or when a brake light signal 10 is detected, the conduction rate of the transistor 76 is lowered and the field current and armature current are increased. let As a result, the charging current of the storage battery 4 also increases, the mechanical driving torque of the generator increases, and the braking performance of the engine improves. In vehicles such as automobiles, the rotational speed of the engine changes from moment to moment depending on the driving conditions, so by performing the above-mentioned control, the energy that is dissipated as frictional heat when the vehicle is braking is restored to the storage battery, and the engine speed is increased during acceleration. It can be used as energy and can be used effectively.

The above is a control operation according to the conventional method. Next, when the storage battery 4 and the electric load (not shown) are cut off during high-speed rotation, a high voltage is generated in the armature winding 1 as described above. In the present invention, a voltage regulator 6 is provided to cope with this problem. That is, when a high voltage is generated in the armature winding 1, the resistor 63a.

The voltage at the voltage dividing point of comparator 63b becomes higher, and the inverting input of comparator 65 becomes larger than the non-inverting input, and its output becomes low level. Therefore, the power transistor 66 is not supplied with base current and is forcibly cut off, thereby preventing a large current from flowing through the transistor 66 and destroying it. The field current flowing through the field winding 2 is attenuated through the flywheel diode 67, and the output voltage of the generator gradually decreases. When the voltage drops below a certain level, the output of the comparator 65 becomes high level, returning to the normal duty control state. Further, in the case where the terminal C of the generator is disconnected or the transistor 76 is broken in an open state, the generated voltage cannot be controlled in the conventional technique. However, in this embodiment, by installing the voltage adjustment circuit 6, the output of the comparator 65 changes between high and low levels according to the rise and fall of the output voltage of one generator, and controls the power transistor 66, thereby preventing the occurrence of overvoltage. be able to.

〔Effect of the invention〕

As is clear from the above embodiments, according to the present invention, in a power generation control device that performs pulse width control using a calculation device, control is achieved in which a power element is not destroyed even when a high-energy surge is applied. Since the method can be provided, it has the effect of improving the reliability of the charging system. Particularly in recent years, there has been a tendency for many electronic devices to be installed in vehicle engines, travel controls, etc., and the present invention can prevent abnormalities in the power supply system, thereby increasing the reliability of the entire vehicle. Furthermore, since the generator has a protection function against disconnection of the terminals of the generator, reliability can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a charging system showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Armature winding, 2... Field winding, 6... Voltage regulator, 7... Control device, 61... Zener diode, 65... Comparator, 66...・Power transistor.

Claims (1)

[Scope of Claims] 1. The operating state of the engine and the generated voltage are taken in and processed by a calculation means, and according to the results, the field current of the charging generator driven by the engine is controlled on and off via a switching means. In the method of controlling the charging generator,
Voltage detection means is provided to directly detect and output a detection signal when the generated voltage exceeds a predetermined value set in advance, and the switching means is forcibly turned off by the detection signal of the voltage detection means. A method for controlling a charging generator, characterized in that: 2. Claims characterized in that the switching means and the voltage detection means are built into the charging generator, and a control device for controlling on/off via the switching means is disposed outside the charging generator. A method for controlling a charging generator according to item 1. 3. The voltage detecting means obtains the detection signal by comparing the generated voltage and the predetermined value set by a Zener diode using a comparator. How to control a charging generator.