JPS62152337A - Vehicle battery charger - 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 The present invention relates to a battery charging device mounted on a vehicle such as a two-wheeled vehicle. The drawings below are partial operation waveform diagrams. In the figure, ACG is a magnetic alternator EX, its power generation (AC) winding, RPC is a full-wave rectifier formed by diodes D and -D, and BAT is the full-wave rectifier of the above-mentioned full-wave rectifier. The battery S CR+ , 8 CR1 charged by the DC output is a thyristor connected in antiparallel to the diodes D and D4, respectively, and is made conductive by a signal from a control circuit C0NT, which will be described later, to short-circuit the AC output. CONT is a control circuit that is composed of a resistor (not shown), a constant pressure diode, a transistor, etc., and detects the voltage of the cough batch IJBAT, and when the value reaches a predetermined value, it turns on the CYRIS/7S CR+ or 5C.
A gate signal is sent at rt, + to make the thyristor conductive, thereby short-circuiting the power AC output to prevent overcharging of the bacteria. In other words, in Fig. 2, fat is the AC output 'city pressure waveform,' is the current waveform of the thyrist 48 CTLl (or SCR,), and (cl is the current waveform of the diode D, (or, ), and the battery terminal voltage is When the value exceeds the specified value, the thyristor SC (or 5CFL) becomes conductive with the threatening current IB flowing through the diode D (or 5CFL). Therefore, the silis f S C1
When the diode D is conductive, the voltage a I B recovery (
(reverse recovery) current 1r flows. Since this current IR contains high frequency components, it often causes radio wave interference, which has disadvantages such as mixing noise into in-vehicle radios and causing malfunctions of other devices. In view of the above drawbacks, the present invention provides an inexpensive device that eliminates the above drawbacks by digitizing the control circuit and always controlling the alternating current output waveform of the generator using an integer multiple. In the charging device, the AC output is rectified to charge the battery, and when the voltage of the battery reaches a predetermined value, the control circuit short-circuits the multiplication of the AC output using a thyristor. A detection unit (first) that detects the voltage as a digital value, a detection unit (second) that detects the zero point of the AC output, and a synthesis unit that synthesizes the detection outputs of the first and second detection units. This is a characteristic feature.

FIGS. 3 and 4 are circuit diagrams and operation waveform diagrams of various parts thereof showing an embodiment of the present invention, and the same reference numerals as in the conventional example indicate equivalent parts. In FIG. 3, C0NT is a control circuit constituting the main part of the present invention. A detection unit that detects the zero point (zero cross) of the output (the figure shows an example in which detection is performed by the calculation unit) synthesizes the digital value and the zero point signal (in the embodiment, the rising waveform of the AC output is used), and the thyristor SCR
, (or 5CRt). To simplify the explanation, we will focus on the diode DI and the thyristor SCa. First, when the head current shown by the solid line in FIG. ,
Enter. On the other hand, since the above-mentioned current is already flowing through the diode D, zero point detection is not performed, and the zero point detection signal is sent to the detection terminal C of the calculation units C and T by the AC output in the next cycle.
This causes the thyristor 5CRI to conduct for a half cycle of AC, short-circuiting the AC and maintaining the battery voltage at a predetermined voltage, as shown in FIG. 3fa). In addition, in FIG. 4(b), the dotted line waveform indicates the current waveform flowing through the diode D. In other words, this is prevented. In other words, in the present invention, when current is flowing through the diode DI (or D!), the corresponding thyristor 5CR3 for this period (half cycle)
(also SCR,) does not conduct, which causes the diode D
, (or), to prevent the generation of high-frequency noise, and in the next cycle, the battery voltage is limited by conduction for half a cycle from the zero point to the zero point of the AC waveform. Other control examples will be explained below using Table 1.

First, in the conversion circuit /D, the battery voltage is 12.5
When the voltage is below V, no output is made to the arithmetic unit CT, so the thyristors 5CRI and SCa are both in the OFF (non-transmitting) state, and the battery BAT is charged by the full-wave rectified output. (Charge i1i, Shu1 i.e. 100% charge) Next 13
When the voltage is V, as described above, only the thyristor 5crt is turned on and off, so that its charge amount becomes 3/4 (75%). Again 1
When the voltage is 3.5V, it is input to the calculation input section A, and during the other half cycle period of the AC output, CYRIS 4 (SCR, or SCR*)
Turn on. Therefore, the charge during this period is tft/2
(50%). In addition, in the 14V state, input to the input section , turns on thyristor SCR (or SCa) for 2 half cycles out of 2 cycles, and turns on thyristor IS (#,
A gate signal is sent to turn on (or SCa+) for half a cycle. The amount of charge at this time is 1/4 (25%)
). When the battery voltage further rises and exceeds 14.5V, input a digital value to input section A, and set thyrist I.
SCR and SCR are alternately turned on for half a cycle of the AC output, and all outputs are shorted. At this time, the amount of charge becomes zero. As described above, according to the present invention, the thyristor is made to conduct intermittently or continuously for at least a half cycle period of AC output in accordance with the detected digital value of the battery voltage, thereby making it easier to charge the battery.
A can be adjusted to prevent overcharging. In addition, as mentioned above, in the synthesis section CT, the required number of gate pulses may be sent out by performing subtraction or addition operations according to the digital input using a counter such as an arithmetic section. The required gate pulse may be formed by comparing the digital input values and using the zero point detection signal as a basis. As is clear from the above description, according to the present invention, it is possible to prevent the generation of high frequency noise without using a large capacitor when charging a battery, thereby preventing noise from entering vehicle equipment or malfunctioning, and furthermore, it is possible to prevent the occurrence of high frequency noise during battery charging without using a large capacitor. This has great practical effects because it can provide a small, inexpensive device that can easily prevent overcharging.

[Brief explanation of drawings]

Figures 1 and 2 are conventional circuit diagrams and operation waveform diagrams of each part thereof,
FIGS. 3 and 4 are circuit diagrams of an embodiment of the present invention and operation waveform diagrams of each part thereof. In the figure, ACG is a generator, EX is a power generation winding, RBC is a full-wave rectifier, Dt -D, ,D,
, D is a diode, DAT is a battery, SC mountain, S
Ca is a thyristor, C0NT is a control circuit, A/D is an analog-to-digital conversion circuit (digital value detection section), C
T is an arithmetic unit (combining unit).

Claims (2)

[Claims] (1) The alternating current output of the generator is full-wave rectified to charge the battery, and when the voltage of the battery reaches a predetermined value, the multiplication of the alternating current output is short-circuited by a thyristor via a control circuit. In the charging device, the control circuit includes a detection unit (first) that detects the battery voltage as a digital value, a detection unit (second) that detects the zero point of the AC output, and detection outputs of the first and second detection units. A vehicle battery charging device characterized by comprising a synthesis section for synthesizing. (2) A patent characterized in that the control circuit conducts the thyristor in accordance with the digital value of the first detection unit, and short-circuits the AC output intermittently or continuously for at least a half cycle period of the AC output. A vehicle battery charging device according to claim (1).