JPH02164234A - Charging equipment - Google Patents

Abstract

PURPOSE:To obtain a charging equipment with good efficiency by turning ON or OFF the equipment at the zero-cross time in half periods of a power wave to duty-control the equipment and by switching-controlling the counted number of ON period through an odd number and that of OFF period through an even number. CONSTITUTION:A commercial AC power supply 1 is connected with a transformer 3 to convert a secondary output voltage into DC and to connect the voltage with a secondary battery 5 to charge the battery. When a relay switch(SW) 1 is closed, the secondary battery 5 is charged with 12V voltage. When SW1 is opened and SW2 is closed, the charging voltage is changed to 24V. A capacitor 9 and a resistance 8 prevent a switching malfunction. A trigger circuit 11 is optically combined with a microcomputer 13, to which zero-cross timing, A/D converted secondary battery voltage and the value of a charging current flowing through the secondary battery are inputted. A zero-cross detection means 19 detects a point for voltage to become zero and counts the point in half periods according to the charging current to duty-control an equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a charging device that rectifies a commercial AC power source to charge a secondary battery, particularly an automobile battery.

[Conventional technology] Currently, the method of charging a secondary battery is to flow a large current at the beginning of charging, reduce the current when the voltage of the secondary battery reaches a certain value, and then increase the current once the voltage reaches that voltage again. The quasi-constant current method, in which the battery is lowered and charged, is often used.

Problem to be solved by invention E 1 In this case, a relatively large current is applied to the secondary coil side of the transformer to which the secondary battery is connected in order to step down the commercial AC power so that it is compatible with the automobile battery. flows. Therefore, if a triac or the like is used as a charging current switching element to control the current on the primary coil side where the current is small, the cost of the switching element can be reduced, but the charging current can be controlled by controlling the phase of the AC wave on the secondary coil side There was a problem in that switching caused pulse noise on the AC power supply side.

On the other hand, the zero-crossing point of the current wave is detected by the zero-crossing switch, and as shown in Fig. 3, it is turned on at about QL for half a cycle.
There is also a method of controlling the 0FFL duty, but although controlling the charging current with this method prevents pulse noise, it increases iron loss in the transformer (which reduces charging efficiency and has a negative effect on the transformer. There was a problem.

The present invention aims to solve the above problems and provide an efficient charging device.

[Means for Solving the Problems 1] In the present invention, when varying the charging current as the secondary battery charging progresses, duty control is performed by turning ON or OFF at zero cross in units of half cycles of the power supply wave. , the switching control is performed by setting the count number of the ON period to an odd number and the count number of the OFF period to an even number.

1 effect] With the above configuration, the half-period wave applied to the transformer in the first ON period (hereinafter referred to as the start phase) is on the side (a) in Fig. 3. (hereinafter this will be referred to as the mountain side) or (b) side (hereinafter this will be referred to as the valley side)
ζ) will not be biased to either side, and the start phase can be alternated between the peak side and the valley side.
Since half-period waves during the period can be distributed at approximately the same ratio on the peak and valley sides, a demagnetizing effect in the transformer can be obtained, and iron loss can be suppressed to a small level. As described above, according to the present invention, a charging device with low cost and high charging efficiency can be obtained.

[Example of idea] Examples thereof will be described in detail below based on the drawings.

In Fig. 1, 1 is a commercial AC power supply, which is connected to a transformer 3 via a switching circuit 2, and converts the secondary output voltage from the transformer 3 into DC via a rectifier 4 made of a diode Pritsuno. , which is connected to the secondary battery 5, that is, the battery of the automobile, and charged.籏i and shz are relay switches that change the photoelectric voltage, and when S-1 is closed, it is connected to the center tap on the secondary coil side of the transformer 3, and the secondary battery is charged with a voltage of 12V. Further, when SWI is opened and SW2 is closed, the charging voltage is switched to 24V. Numeral 6 is a varistor that protects the circuit by dissipating it to ground in the event of a lightning strike or abnormally high voltage.

The switching circuit 2 includes a triac 7, and in parallel with the triac 7, a capacitor 9, a resistor 8, and a varistor 10. Of these, the capacitor 9 and the resistor 8 are
It functions to remove the noise applied to the triac 7,
The varistor 10 prevents switching malfunctions in performing duty control of the charging current, and also suppresses abnormal overvoltage to the triac 7.

11 is the triac 1 which provides the date signal of the triac 7;
In the circuit, it is optically coupled to a microcomputer 13 serving as a data control means through a seven-oto coupler 12 consisting of a light emitting diode LED and seven otothyristors. 20 is the commercial power supply voltage [1] stepped down to the voltage for driving a microcomputer, etc.;
A transformer 19 supplied to the control power source 21 is a zero cross detection means that detects the zero cross timing of the power supply current flowing to the secondary coil side of the transformer 3 through the control power source. The microcomputer 13 also includes the zero cross detection means 1.
The zero cross timing given by 9, the secondary battery voltage converted to ^/D by the ^/D converter/eater 22, and the charging current value flowing through the secondary battery detected by the current sensor 18 are input. In addition, in the microcomputer 131, 15 is CF
'U, 16 is a memory that stores duty control data (described later) for charging current control.

Next, regarding charging current control in the above circuit, Fig. 2, f
:t This will be explained based on the S3 diagram.

FIG. 2 shows an example of duty control in the charging device according to the embodiment of the present invention. The illustrated waveform is a current waveform flowing through the secondary coil of the transformer, and is an AC waveform because it is directly connected to a commercial power source and has not yet been rectified.゛Then, the zero cross detection means 19 detects the voltage as 0.
The duty control is performed by detecting the point where the battery becomes, and counting the number of peaks and valleys in half-cycle units according to the charging current flowing through the secondary battery. In other words, ON period T
The power supply current value is adjusted by changing the ratio between the on period and the OFF period Toff, and charging is performed in a gradual manner according to the state of charge of the secondary battery. In this embodiment, as shown in Table 1 on the next page, the duty control is performed by setting the half-cycle waveform count number at Ton to an odd number and the count number at TO "" to an even number. It balances the half-period waveform that appears in the.

In Table 1 below, tiS2 and FIG. 3 will be compared and explained. FIG. 3 shows an example of duty control with a duty ratio of 55%, that is, an ON count of 11 in Ton and an OFF count of 9 in Tofr.

In this case, when looking at the half-cycle waveform that appears on the peak side during 0N115111Ton and the half-cycle waveform that also falls on the valley side, the ratios of the two are different. In other words, while there are 6 waveforms on the peak side, there are 5 waveforms on the valley side. The start phase at Ton enters from the mountain side like the previous Ton, and the waveform that falls on the mountain side accounts for a large proportion of the total.On the other hand, in Fig. 2, the duty ratio is 55%, and the starting phase is from the mountain side. At Ton, there are 3 on the mountain side and 2 on the valley side, but O with an OFF count of 9.
In the next Ton after the FF period, the start phases are switched and there are two on the peak side and three on the valley side.

Therefore, when viewed as a whole, the waveforms on the peak side and the waveforms on the valley side have approximately the same ratio.

In other words, as shown in Figure 4, if the ON count number is an odd number, the OF
By controlling the duty with an even number of F counts, the start phase alternates every Ton, and the output and valley sides have almost the same ratio, so in the transformer? +￥ Magnetic effect is created and iron loss is reduced.

[Effects of the Invention 1 As described above, according to the present invention, a relatively inexpensive switching element is used to duty-control a commercial AC power supply by setting the ON count number to an odd number and the OFF count number to an even number in half-cycle units, Control photoelectric current. Therefore, even if the alternating current wave is switched intermittently, the start phase is applied to the transformer alternately as peaks and valleys during each ON period, and overall, the half-period waves on the peak side and the valley side are applied at almost the same ratio, so This creates a degaussing effect, which reduces iron loss and prevents harmful Hp M from affecting the transformer.Also, the zero-crossing point of the power supply current is always detected and switching is performed at the zero-crossing point, resulting in duty control. Therefore, effects such as not inducing pulse noise on the power supply side can be obtained, and therefore, according to the present invention, a charging device that is low cost, has high charging efficiency, and does not give noise to the power supply side can be obtained. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a 11-way diagram showing a charging device according to an embodiment of the present invention. @2 Figure is an explanatory diagram showing an example of duty control same as above. FIG. 3 is an explanatory diagram showing an example of duty control in a conventional charging device. 1 is an AC power supply, 2 is a switching circuit, 3 is a transformer, 5
13 is a secondary battery, and 13 is a microcomputer serving as a duty control means.

Claims (1)

[Claims] In a photoelectric device that rectifies AC power and supplies it to a secondary battery, a current switching element connected to the primary coil side of a transformer, a charging current value flowing to the secondary battery, and a zero-cross timing of the power supply current provided from the AC power supply. and a duty control means for controlling ON and OFF of the current switching element based on the above, and the duty control means sets the duty to an odd number for the ON period and an even number for the OFF period, in units of half cycles of the power supply current. A charging device characterized by controlling.