JPS6013258Y2 - DC power supply - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a DC power supply device, particularly a DC power supply device having a battery that supplies power to a DC load, and a converter that rectifies an external AC power supply voltage to supply power to the DC load and/or battery. A predetermined current for the converter
This invention relates to a DC power supply device that is controlled to provide voltage characteristics.

For example, in leisure vehicles such as motor homes, when the DC load is supplied with power from the battery while the vehicle is running,
A DC power supply device is used that supplies power to the DC load and/or battery via a converter when an external AC power source is available.

The converters used in this type of leisure vehicle are: 1) capable of being efficiently charged in a relatively short period of time when external AC power can be used; 2) the battery is not overcharged even if external AC power is continuously applied for a long time; ■Being able to obtain stable charging characteristics even when the ambient temperature changes; ■Being able to reduce the number of times battery maintenance, such as replenishing liquid, etc., must be performed; and ■Being free from troubles that may occur due to malfunctions. .

For this reason, in the DC power supply device installed in the above-mentioned leisure vehicle, for example, when power is supplied from an external power source, when the terminal voltage of the battery is low, the battery is charged with a large current, and when the battery is close to being fully charged, it is charged with a relatively large current. It is desirable to charge with a small current.

Furthermore, in general, in this type of DC power supply, overcurrent occurs when charging a battery with an extremely low battery terminal voltage, or when the battery is mistakenly connected in reverse and charging is performed, causing damage to circuit components, especially semiconductor devices. The stop may be destroyed by the overcurrent.

Therefore, it is desirable to protect circuit components from overcurrent.

This invention is legally aimed at solving the above points.
The purpose of this is to provide the converter with predetermined current/voltage characteristics and to improve the response speed so that the battery can be charged satisfactorily.

This will be explained below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the DC power supply device of the present invention, FIGS. 2 and 3 show the configuration of an embodiment of the control circuit shown in FIG. 1 and the control characteristics of the control circuit, and FIGS. FIG. 5 shows another embodiment of the control circuit section shown in FIG. 1 and its control characteristics, and FIGS. 6 and 7 show configurations of other embodiments of the DC power supply device of the present invention, respectively.

In FIG. 1, the automatic switching contact 10 is a normally closed contact, and when it is necessary to supply power to a load in a place where external AC power cannot be obtained, the automatic switching contact 10 is connected to the battery terminals 3 and 3'. Power is supplied to the DC load via the

Incidentally, the above-mentioned battery may be considered to be a dedicated battery different from the battery used when starting a mobile object, such as an automobile.

On the other hand, when AC power is available, when AC voltage is applied to the terminals 1 and 1', the relay winding 11 is energized and the actual switching contact 10 is opened, and the load from the battery is switched off. The power supply is stopped, and power is directly supplied to the load from the load converter circuit section 4.

At the same time, the battery is charged from the battery charging converter circuit section 5 in parallel.

The battery charging converter circuit section 5 includes a thyris 14.
15, it is controlled by a signal from the control circuit 8, as will be described later.

That is, the charging current from the battery charging converter circuit section 5 to the battery is detected by the current detection circuit section 7, and the terminal voltage of the battery is detected by the voltage detection circuit section 9.

The thyristors 14 and 15 are controlled by either the current or the voltage to provide desired current/voltage characteristics.

Current transformer 1 in the current detection circuit section 7
6, the primary winding 13, 13' is inserted into the battery charging converter circuit section 5.

The output of the secondary winding is full-wave rectified and appears on terminals 17 and 17', and is led to the control circuit section 8.

Further, the voltage detection circuit section 9 is configured to output the voltage between the battery terminals 3 and 3' to the terminals 18 and 18', and this voltage is guided to the control circuit section 8.

On the other hand, DC voltages (+2) and (-2) are applied to the control circuit section 8 from the power supply section 40 exclusively for the control circuit section.
It is also used as a power supply for the gate circuit power supply section 6 to the control circuit section 8 with DC voltage (+1), (-1
) is applied and used as a power source for controlling the gates of the thyristors 14 and 15.

FIG. 2 shows an embodiment of the configuration of the control circuit section 8 shown in FIG. A voltage signal from the voltage detection circuit section 9 described above is input to 18'.

Also terminals (+1), (-1) and (+2), (-2)
are applied with voltages from the aforementioned power supply units 6 and 40, respectively.

FIG. 3 shows the control characteristics of the control circuit section 8 shown in FIG.
When □ has not been reached, the battery is controlled not to be charged, and the charging current for the battery is kept in a constant current state until the battery terminal voltage □ reaches the first predetermined level V1 to the second predetermined level V2. When the battery terminal voltage (2) reaches the second predetermined level V2, the battery terminal voltage is controlled to be maintained at a constant level.

By providing these current/voltage characteristics, the battery will not be charged when the battery terminal voltage is extremely low or when the battery is reversely connected, thereby making it possible to prevent circuit elements from being destroyed due to overcurrent. .

Further, it is possible to charge the battery with a large current at the beginning of charging, and to perform constant voltage control to prevent an overcurrent state at the end of charging.

In FIG. 2, the current signal supplied to terminals 17, 17' is divided by resistors R29 and R30, and the current signal is divided by resistors R29 and R30.
9 to the base of the transistor TR5.

On the other hand, the voltage signal supplied to terminals 18 and 18' is connected to the resistor R□
6? The voltage is divided by R27, R28, and R1° and applied to the base of transistor m via Zener diode ZD2.

For this reason, diode D9 and Zener diode ZD2
constitutes a maximum value detection circuit section for the base of the transistor TR5, and the terminal voltage of the terminals 3 and 3' of the battery is at a predetermined first voltage level Vt (voltage level V1 shown in FIG. 3). While the current signal is still at a low level that exceeds the current level, control by the current signal becomes effective, and when the terminal voltage exceeds the predetermined second voltage level V2 (voltage level V2 shown in Figure 3), the above-mentioned Control using voltage signals becomes effective.

Hereinafter, the control of the thyristors 14 and 15 shown in FIG. 1 will be explained, and the control of the thyristors 14 and 15 shown in FIG. 2 will be explained as well.

Assuming that the transistor TR5 is now in the off state, the full-wave rectified waveform DC voltage (1 in the figure) applied to the terminals (+2) and (-2) passes through the diode D7 to my
5, capacitor q1 and Zener diode i'ZD,
The voltage is maintained at constant voltage.

The constant voltage (2 in the figure) is connected to a resistor R1. R1゜,
The capacitor C7 is charged via the diode D8.

When the terminal voltage of capacitor C7 reaches a predetermined voltage, ie the switching voltage of switching diode SD, switching diode SD is turned on and generates a voltage across resistor R3.

As a result, assuming that the transistor TR is in the on state, the transistor TR2 is turned on, and accordingly the transistor TR1 is turned on.

That is, the DC voltage applied to the terminals (+1) and (-■) is supplied to the terminals 14' and 15' via the transistor TR, turning on the thyristors 14 and 15 shown in FIG.

1 is the full-wave rectified waveform voltage between terminals (+2) and (-2),
The voltage is divided by resistors RIO and R11 and applied to the base of transistor TR1.

Therefore, each time the voltage 1 becomes approximately zero potential every half cycle, the transistor TR4 is turned off, and accordingly, the transistor TR is turned on to discharge the charge in the capacitor C7.

That is, the switching diode SD is turned off to eliminate the gate signal for the thyristor 14, 15 shown in FIG. 1, and waits for the gate signal to be applied again during the next half cycle.

This means:

That is, thyristor 14.15 is turned on with a slight phase lag at the beginning of each half cycle and turned off at the end of each half cycle.

At this time, the conduction angles of the thyristors 14 and 15 are designed to be sufficiently large.

At this time, as described above, the capacitor C7 is charged to a constant voltage of 2 each time the transistor TR3 is once turned on and then turned off.

Due to the charging time constant at this time, there is a time delay before the terminal voltage of the capacitor C7 reaches the switching voltage of the switching diode SD. There is a limit.

In order to solve this problem, in the case of the present invention, 1 is applied to the DC voltage of the gold wave rectified waveform through the resistor R7 to the point A shown in the figure.

That is, for capacitor C7, from voltage to resistor R□4
．． R1□, a first charging circuit that charges through the diode D8, and a second charging circuit that charges the voltage from 1 through the low loss B7 so that the capacitor C7 is charged at a sufficiently high speed. I am considerate.

That is, the indicated resistance R□4. A second charging circuit is prepared via resistor R7 with a relatively large resistance value compared to the resistance value of the circuit via R1□ and diode D3, and the conduction angle of the thyristor 14 and 15 shown in FIG. I'm trying to make it as big as possible.

Note that the resistance value given to the resistor R7 is such that when the transistor TR5 is kept in the on state, the terminal of the capacitor C7 is charged when the capacitor C7 is charged only via the second charging circuit. Before the voltage reaches the switching voltage of the switching diode SD, the transistor TR1 is turned off and the transistor TR
3 is chosen to be the smallest value in the range of values that guarantees that it is turned on.

As long as the transistor TR3 is in the OFF state, the thyristors 14 and 15 shown in FIG. The potential of B is kept at zero potential by the transistor TR5.

Therefore, the first charging circuit that charges the capacitor C7 is disabled, and the terminal voltage of the capacitor C7 is changed to the transistor TR before the switch diode SD is turned on.
3, the transistor TR2
is never turned on.

That is, the thyristors 14 and 15 shown in FIG. 1 are completely kept in the OFF state.

In other words, when the transistor TR6 is in the on state (the state in which the battery terminal voltage is higher than the first voltage level V□) and the transistor TR6 is in the off state, the first
The illustrated thyristor 14,15 is made to have a sufficiently large conduction angle to charge the battery, but the transistor T
When R6 is in the on state, the above thyristor 14.15
is completely turned off and the charging current to the battery is cut off.

Therefore, as is clear from reference to FIG. 3, when the voltage at battery terminal 3°3' shown in FIG. 1 is between the first voltage level V□ and the second voltage level V2, the charging current to the battery is is the resistor R29 on the lower right side of Figure 2.
Control is performed to maintain the current level determined by the level of the voltage dividing point divided by R30 and R30.

That is, the converter circuit section 5 is made to have constant current characteristics.

When the voltage at the battery terminals 3, 3' reaches the second voltage level V2, the voltage at the terminals 3, 3' is determined by the voltage dividing point between the resistors R27 and R28 at the center right in FIG. It is controlled to maintain the voltage level V2.

That is, the converter circuit section 5 is made to have constant voltage characteristics.

In this case, the control for the transistor TR6 is controlled by the transistor TR6 connected between the battery terminals 18, 18'.
A resistor R1, which determines the base potential of 6.

Performed by R2o.

That is, when the battery terminal voltage is below the first voltage level V1, the transistor T'R6 is kept off because the base potential is low, while when the battery terminal voltage is above the first voltage level V□. In some cases, the base potential is sufficiently high and transistor TR6 remains on.

Therefore, the battery terminal voltage reaches the first voltage level V
If it is less than 1, transistor TR2 will not be turned on by transistor TR6, and as a result, the battery will not be charged.

Therefore, if the battery terminal voltage is extremely low or if the battery is mistakenly connected in reverse, the battery is not charged, so that damage to circuit elements due to overcurrent can be prevented.

Note that when a voltage is first applied to the terminals (+2) and (-2), the capacitor C9 forms a parallel circuit with the capacitor C7, and has a so-called soft start function.

FIG. 4 shows another embodiment of the configuration of the control circuit section 8 shown in FIG. 1, and FIG. 5 shows its control characteristics.

Symbols in the figure correspond to FIGS. 2 and 3, and a relay winding RELAY 2 and a diode D1o are connected in series and located slightly to the left of the center of the diagram, and a relay contact S of the relay winding RELAY 2 is located. is inserted into the collector of the transistor m□.

Here, the relay contact S is a normally open contact.

The configuration shown in FIG. 4 has approximately the same configuration as the configuration shown in FIG. The only difference is that it is composed of RELAY2 and diode D1o.

Therefore, it is clear that the configuration shown in FIG. 4 gives the converter circuit section 5 the current/voltage characteristics as shown in FIG. 5, similar to the configuration shown in FIG. Explanation will be omitted.

FIGS. 6 and 7 each show the configuration of another embodiment of the DC power supply device of the present invention, and the reference numerals in the figures correspond to those in FIG. 1.

In the case of the embodiment shown in FIG. 6, the converter circuit section 5 serves both as the battery charging converter shown in FIG. 1 and the DC load converter.

A battery and a DC load are connected together to the terminals 3 and 3' shown in FIG. 6, and the converter circuit section 5 allows the battery to be charged in a floating manner.

In this case as well, by providing the control circuit section 8 shown in FIG. 6 with the configuration shown in FIG. 2 or 4, the converter circuit section 5 has current/voltage characteristics as shown in FIG. 3 (FIG. 5). It becomes possible to give

In the case of the embodiment shown in FIG. 7, the converter circuit section 5 also serves as the battery charging converter shown in FIG. 1 and the DC load converter.

The only difference from the configuration shown in FIG. 6 is that the current detection circuit section 7
The only difference is that the primary winding of the current transformer is inserted into the external AC power input terminals 1 and 1'.

Therefore, it goes without saying that the embodiment shown in FIG. 7 also provides the converter circuit section 5 with current/voltage characteristics similar to the case shown in FIG.

As explained above, according to the present invention, the current/voltage characteristics as shown in FIG. 3 (FIG. 5) can be given to the converter circuit section 5.

Therefore, if the battery terminal voltage is extremely low or the battery is reversely connected, that is, the battery terminal voltage is
If the voltage level V1 has not been reached, the battery is not charged, and as a result, circuit elements can be prevented from being destroyed by overcurrent.

Further, in the above embodiment, when the battery terminal voltage reaches the second voltage level V2, charging is performed under constant voltage control. (1) Provide current/voltage characteristics such that the charging current decreases in proportion to the increase in the battery terminal voltage after reaching the voltage level, or (2) perform control under a constant voltage when the second voltage level is reached. , then control is performed using a constant current that is lower than the constant current level at the initial stage of charging, and then constant voltage control is performed at a third voltage level, giving a stepped current/voltage characteristic. Needless to say, it's a good thing.

According to the present invention, as shown in FIGS. 2 and 4, a constant voltage charging circuit for capacitor C7 is controlled by transistor m.

Further, the control over the converter is renewed every half cycle of the external AC power supply voltage.

Therefore, the switching diode SD can be controlled efficiently.

Furthermore, since the full-wave rectified waveform voltage 1 is applied to the switching diode SD via the resistor 17, it is possible to make the conduction angle of the thyristors 14 and 15 sufficiently large.

[Brief explanation of the drawing]

FIG. 1 shows the configuration of an embodiment of the DC power supply device of the present invention, FIGS. 2 and 3 show the configuration of an embodiment of the control circuit shown in FIG. 1 and the control characteristics of the control circuit, and FIGS. FIG. 5 shows another embodiment of the control circuit shown in FIG. 1 and its control characteristics, and FIGS. 6 and 7 respectively show other embodiments of the DC power supply device of the present invention. In the figure, 5 is a converter circuit section, 7 is a current detection means, 8 is a control circuit section, 9 is a voltage detection circuit section, R29, R3o, R
18, D9. R16, R2□, R28, R17, ZD2
゜R15 is the maximum value detection circuit section, R19, R2o, TR6
, D.I. or RELAY2. D. is battery voltage detection means, TR5, C8, TR3, SD
, TR2, and TR□ represent a transistor, a capacitor, a transistor, a switching diode, a transistor, and a transistor included in the switching control circuit section, respectively.

Claims (1)

[Scope of utility model registration request] A DC power supply device having a battery that supplies power to a DC load, and a converter that rectifies an external AC power supply voltage to supply power to the DC load and/or battery, current detection means that detects a current component flowing through the converter, and an output of the converter. voltage detection means for detecting a voltage component on the side; a maximum value detection circuit section for combining the output voltage of the current detection means and the output voltage of the voltage detection means; a battery voltage detection means for detecting the terminal voltage of the battery; a pulse generation circuit section that includes a capacitor to which a voltage is applied and is charged by the DC voltage, and controls the pulse rise time by timing the charging time to the capacitor;
a switching control circuit unit that supplies a control signal to the converter using an output from the pulse generation circuit unit;
and a switching circuit for controlling the application of the DC voltage to the pulse generation circuit according to the output signal from the maximum value detection circuit and the detection signal from the battery voltage detection means, the pulse generation circuit being The clocking operation by the capacitor is reset every half cycle of the external AC power supply voltage, and the pulse rise time corresponding to the output from the switching circuit is determined every half cycle, and the pulse generation In order to speed up the charging time for charging the capacitor, the circuit is provided with a second charging circuit to which current is supplied from the external AC power supply voltage in addition to the first charging circuit from the maximum value detection circuit side. and a DC power supply device characterized in that the converter is provided with predetermined current/voltage characteristics, and the converter output is made to be zero when the battery terminal voltage does not reach the predetermined voltage level.