KR20110131912A - Battery charger for a vehicle with wide output voltage range - Google Patents

Abstract

PURPOSE: A battery charger for a vehicle is provided to offer an excellent withstand voltage characteristic by serially arranging switching units each other. CONSTITUTION: A converter part(102) is arranged in the primary side of a first transformer(114a). A rectifier is arranged in the secondary side of the first transformer. The rectifier is converted from full bridge circuit to a half bridge circuit according to a control signal. The rectifier is also converted from the half bridge circuit into the full bridge circuit. The rectifier comprises a first, second, third, and fourth diode(D1,D2,D3,D4).

Description

BATTERY CHARGER FOR A VEHICLE WITH WIDE OUTPUT VOLTAGE RANGE}

The present invention relates to a vehicle charger capable of outputting a wide range of output voltage while having excellent withstand voltage characteristics.

A vehicle charger is a device that provides a voltage required for a vehicle, and generally includes two stages of a power factor correction unit (PFC) and a DC / DC converter for power factor improvement.

In this case, since the DC / DC converter is composed of one stage, elements included in the DC / DC converter have to have strong withstand voltage characteristics in order to withstand the withstand voltage. In other words, expensive devices have been required, thus increasing the manufacturing cost of the charger.

In addition, the charger generally used by arranging transformers in parallel. However, if the transformers are implemented in parallel, current may flow unidirectionally to a specific transformer if the turns ratio and inductance value of the transformers do not match. As a result, the transformer could cause abnormal heat generation and there was a risk of breakage.

Moreover, the charger has been difficult to implement a wide range of output voltages.

In addition, in the vehicle, even if the input power is different, it is always necessary to output the same output voltage, but the charger could not output the same output voltage if the input power is different.

It is an object of the present invention to provide a vehicle charger capable of outputting a wide range of output voltages while having excellent withstand voltage characteristics.

In order to achieve the above object, a vehicle charger according to an aspect of the present invention comprises a first transformer; A converter unit arranged on the primary side of the first transformer; And a rectifier arranged on the secondary side of the first transformer. Here, the rectifier is switched from a full bridge circuit to a half bridge circuit or from the half bridge circuit to the full bridge circuit according to a control signal.

According to another aspect of the present invention, a vehicle charger includes a first transformer; A second transformer; And

And a converter unit connected to the primary side of the first transformer and having a first switching unit including a plurality of first switches and a second switching unit connected to the primary side of the second transformer and including a plurality of second switches. . Here, the first switching unit and the second switching unit are connected in series.

In accordance with another aspect of the present invention, a charger for a vehicle includes a converter unit; And a rectifier for outputting an output voltage in response to a current output from the converter. Here, even when the input power input to the converter is the same, the magnitude of the output voltage varies according to a control signal for controlling the rectifier.

In the vehicle charger according to the present invention, since the rectifier may be switched from a full bridge circuit to a half bridge circuit or from a half bridge circuit to a full bridge circuit, an advantage of outputting the same output voltage even if different size input voltages are inputted. have. Of course, when input voltages of the same magnitude are input, output voltages of different magnitudes may be output.

In addition, since the switching units included in the current converter of the vehicle charger are arranged in series with each other, it may have excellent withstand voltage characteristics. Therefore, since the switches used in the current converter do not have to use expensive products, the manufacturing cost of the charger can be reduced.

1 is a circuit diagram illustrating a vehicle charger according to a first embodiment of the present invention.
FIG. 2 is a view illustrating an operation flow of the vehicle rechargeable battery of FIG. 1.
3 is a circuit diagram illustrating a vehicle charger according to a second embodiment of the present invention.
4 is a view illustrating an operation flow of the vehicle rechargeable battery of FIG. 3.
5 is a timing diagram illustrating an operation flow of the charger of FIG. 3 according to an embodiment of the present invention.
6 and 7 illustrate output voltages according to an embodiment of the present invention.
8 is a timing diagram illustrating on / off times of switches according to a first duty ratio according to an embodiment of the present invention.
9 is a timing diagram illustrating on / off times of switches according to a second duty ratio according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The vehicle charger may use commercial power, that is, 110V _ac and 220V _ac , and is preferably implemented to output various sizes of output voltages due to the characteristics of the vehicle.

Accordingly, the present invention proposes a vehicle charger capable of outputting various output voltages, in particular capable of outputting a wide range of output voltages. For example, the vehicle charger of the present invention may implement 100V to 500V.

In addition, the vehicle charger may be implemented to have a strong withstand voltage characteristics.

Hereinafter, various embodiments of the vehicle chargers of the present invention will be described with reference to the accompanying drawings.

1 is a circuit diagram illustrating a vehicle charger according to a first embodiment of the present invention, and FIG. 2 is a view illustrating an operation flow of the vehicle rechargeable battery of FIG. 1.

Referring to FIG. 1, the vehicle charger according to the present embodiment includes an input circuit unit 100, a current-fed converter section 102, a transformer unit 104, a rectifier 106, and a filtering section 108. ).

The input circuit unit 100 is a circuit for transferring the AC input power V _ac as shown in FIG. 2 to the next stage and may include an input filter and a bridge diode 120.

The current converter 102 is arranged on the primary side of the transformers 114a and 114b of the transformer unit 104 and includes an inductor L1, a first switching unit 110a and a second switching unit 110b. do.

The inductor L1 is a device that stores energy and is connected to the input circuit unit 100.

The first switching unit 110a is connected to the inductor L1 and includes a plurality of switches 112a, 112b, 112c and 112d. Here, each of the switches 112a, 112b, 112c, and 112d may be a MOSFET switch, and on / off control by control signals S1, S2, S3, and S4 input to its gates. Can be.

The first switching unit 110a is connected to the primary side of the first transformer 114a. Specifically, the node n1 between the switches 112a and 112c is connected to one end of the primary side of the first transformer 114a, and the node n2 between the switches 112b and 112d is the first transformer. It is connected to the other end of the primary side of 114a.

The second switching unit 110b is connected to the first switching unit 110a and includes a plurality of switches 112e, 112f, 112g, and 112h. Here, each of the switches 112e, 112f, 112g, and 112h may be a MOSFET switch, and may be controlled on / off by control signals S5, S6, S7, and S8 input to its gates.

The second switching unit 110b is connected to the primary side of the second transformer 114b. Specifically, the node n3 between the switches 112e and 112g is connected to one end of the primary side of the second transformer 114b, and the node n4 between the switches 112f and 112h is connected to the second transformer. It is connected to the other end of the primary side of 114b.

According to an embodiment of the present invention, the first switching unit 110a and the second switching unit 110b are connected in series with respect to the inductor L1.

On the other hand, in the conventional charger, the charger uses only one switching unit, and as a result, the devices of the switching unit had to withstand a large withstand voltage. Therefore, the charger had to use only expensive devices capable of withstanding a large withstand voltage, and as a result, the manufacturing cost of the charger had to be increased.

However, since the charger of the present embodiment uses the switching units 110a and 110b connected in series, the current i _L passing through the inductor L1 flows through the switching units 110a and 110b. As a result, the withstand voltages that each of the switching units 110a and 110b have to withstand are lowered, so that the withstand voltages can be sufficiently withstand even when the switches 112a to 112h that are not expensive are used. Therefore, the manufacturing cost of the charger can be lowered.

The transformer unit 104 includes a plurality of transformers 114a and 114b.

The primary side of the first transformer 114a is connected to the first switching unit 110a and the secondary side is connected to the rectifying unit 106.

The primary side of the second transformer 114b is connected to the second switching unit 110b and the secondary side is connected to the rectifying unit 106.

Although the turns ratio of the transformer 114a or 114b is not mentioned, it may be variously set according to the design purpose.

The rectifier 106 is connected to the secondary side of the transformers 114a and 114b and may be implemented as a full bridge circuit, for example, as shown in FIG. 1. Here, one end of the secondary side of the transformers 114a and 114b is connected to the node n5 between the diodes D1 and D2, and the other end is connected to the node n6 between the diodes D3 and D4. .

In addition, the rectifier 106 may further include a capacitor C1 connected to the node n7 between the diodes D1 and D3.

The filtering unit 108 may be connected to the rectifying unit 106 to remove noise and the like, and may be, for example, an LC filter including an inductor L2 and a capacitor C2.

On the other hand, the voltage output from the filtering unit 108 means the output voltage (V _out ) of the charger, the output voltage (V _out ) has a DC voltage as shown in FIG.

According to an embodiment of the present invention, the output voltage V _out may be varied by varying the duty ratio according to the on / off ratio of the switches 112a to 112h. Details thereof will be described in detail in the second embodiment.

In other words, the vehicle charger of the present embodiment may output the output voltage V _out of various sizes by changing the duty ratio according to the on / off ratio of the switches 112a to 112h included in the current converter 102. In addition, the switching units 110a and 110b are arranged in series with respect to the inductor L1 to implement excellent withstand voltage characteristics.

In FIG. 1, the converter unit 102 includes only two switching units 110a and 110b, but may be implemented as three or more switching units connected in series. Of course, as the number of switching parts increases, the number of transformers also increases.

3 is a circuit diagram illustrating a vehicle charger according to a second embodiment of the present invention, and FIG. 4 is a view illustrating an operation flow of the vehicle rechargeable battery of FIG. 3.

Referring to FIG. 3, the vehicle charger of the present embodiment includes an input circuit unit 300, a current converter unit 302, a transformer unit 304, a rectifier unit 306, and a filtering unit 308.

Since the remaining components except for the rectifier 306 are the same as in the first embodiment, detailed description of the same components will be omitted.

The rectifier 306 includes a first capacitor C1, diodes D1 to D4, a third switch 320, and a second capacitor C2.

The first capacitor C1 is connected to one end of the secondary side of the transformers 314a and 314b.

The diodes D1 to D4 form a full bridge circuit and are connected to the first capacitor C1. Specifically, node n5 between diodes D1 and D2 is connected to first capacitor C1, and node n6 between diodes D3 and D4 is connected to transformers 314a and 314b. It is connected to the other end of the secondary side.

The third switch 320 is, for example, a MOSFET switch and is connected to the node n6 and the ground between the diodes D3 and D4 as shown in FIG.

According to an embodiment of the present invention, when the rectifier 306 is to be implemented as a full bridge circuit, the third switch 320 is turned off and the rectifier 306 is to be implemented as a half bridge circuit. In this case, the third switch 320 is turned on. However, in the case of the half bridge circuit, the output voltage V _out is doubled as compared to the full bridge circuit. This is because the second capacitor C2 is charged when the current flows through the bridge circuit, and the charge charged in the second capacitor C2 is discharged when the current does not flow through the bridge circuit.

As a result, the output voltage V _out may be the same even if the magnitude of the input power source V _ac is different. For example, assuming that the rectifier 306 is implemented as a full bridge circuit when a 220 V input power source V _ac is applied to obtain an output voltage V _out of 450 V, the 110 V input power source V _ac is obtained. When applied, the rectifier 306 may be configured as a half bridge circuit to obtain the same output voltage V _out of 450V.

According to another embodiment of the present invention, the vehicle charger may turn on the third switch 320 at an appropriate point in time to switch the circuit of the rectifier 306 from the full bridge circuit to the half bridge circuit, thereby providing the same input power supply (V _ac). Higher output voltage V _out may be obtained.

Of course, the charger operates as shown in Fig. 4 similarly to the first embodiment.

Hereinafter, the overall operation of the vehicle charger will be described.

5 is a timing diagram illustrating an operation flow of the charger of FIG. 3 according to an embodiment of the present invention, and FIGS. 6 and 7 are views illustrating output voltages according to an embodiment of the present invention.

3 and 5, the switches 312a, d, e, and h are turned on / off at regular intervals, and the switches 312b, c, f, and g are also constant. It is turned on / off in cycles.

Specifically, in to to t1, all the switches 312a to 312h are turned on, and as a result, energy is accumulated in the inductor L1. As a result, the current i _L flowing through the inductor L1 increases.

Subsequently, at t1 to t2, the switches 312a, d, e, and h remain on and the switches 312b, c, f, and g are turned off. In this case, the energy accumulated in the inductor L1 is transferred to the secondary side of the transformers 314a and 314b through the transformers 314a and 314b to output a DC output voltage V _out having a predetermined magnitude. As a result, the charge of the inductor L1 is discharged, so that the current i _L flowing through the inductor L1 is reduced.

Subsequently, at switches t2 to t3 all the switches 312a to 312h are turned on again, and as a result, energy is accumulated in the inductor L1.

Subsequently, at t3 to t4, the switches 312a, d, e and h are turned off and the switches 312b, c, f and g remain on. In this case, energy accumulated in the inductor L1 is transferred through the transformers 314a and 314b to output a DC output voltage V _out having a predetermined magnitude.

Subsequently, the processes of t1 to t4 are repeatedly performed.

In short, the vehicle charger of the present embodiment controls the on / off of the switches 312a to 312h, that is, the duty ratio, to output a desired output voltage V _out .

The charger may maintain the rectifier 306 as a full bridge circuit or a half bridge circuit, or may convert the full bridge circuit to a half bridge circuit or a half bridge circuit to a full bridge circuit at a specific point in time.

As a result of the actual test of the vehicle charger, it was confirmed that the output voltage V _out outputs 150V and 450V as shown in FIGS. 6 and 7.

That is, the vehicle charger of the present invention can implement a wide range of output voltage (V _out ), for example, 100V to 500V.

However, in order to implement the wide range output voltage V _out , the vehicle charger sets the duty ratio appropriately as described below.

FIG. 8 is a timing diagram illustrating on / off times of switches according to a first duty ratio according to an embodiment of the present invention, and FIG. 9 is ON of switches according to a second duty ratio according to an embodiment of the present invention. A timing diagram showing on / off times.

8 and 9, the time that all the switches 312a to 312h are turned on in FIG. 8 is relatively shorter than the time that the switches 312a to 312h are turned on in FIG. 9. On the other hand, the time that energy accumulated in the inductor L1 is transferred to the secondary side of the transformers 314a and 314b is longer in FIG. 8 than in FIG.

In the case of using the duty ratio shown in FIG. 8, the charger outputs an output voltage V _out of 300V, whereas in the case of using the duty ratio shown in FIG. 9, the charger outputs an output voltage V _out of 450V. Was output. Here, 220 V _ac was used as the input power source (V _ac ).

That is, by controlling the duty ratios according to the on / off times of the switches 312a to 312h using the control signals S1 to S8, the charger may output a wide range of output voltage V _out . .

The embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

100: input circuit portion 102: current type converter portion
104: transformer section 106: rectifier section
108: filtering unit 110: switching unit
112: switch 114: transformer
300: input circuit portion 302: current type converter portion
304: transformer section 306: rectifier section
308: filtering unit 310: switching unit
312 switch 314 transformer
320: third switch

Claims (13)

A first transformer;
A converter unit arranged on the primary side of the first transformer; And
Including a rectifier arranged on the secondary side of the first transformer,
And the rectifier is switched from the full bridge circuit to the half bridge circuit or the half bridge circuit to the full bridge circuit according to a control signal. The method of claim 1, wherein the rectifying unit,
A first diode and a second diode connected in parallel to one end of the secondary side of the first transformer;
Third and fourth diodes connected in parallel to the other ends of the secondary side of the first transformer; And
One end is connected to the node between the third diode and the fourth diode, and the other end includes a first switch connected to ground,
And the first to fourth diodes form the full bridge circuit, and the full bridge circuit is switched to the half bridge circuit as the first switch is turned on. The method of claim 2, wherein the rectifying unit,
A first capacitor connected to one end of the secondary side of the first transformer and a node between the first diode and the second diode; And
And a second capacitor coupled to the node between the first diode and the third diode. The vehicle charger of claim 2, further comprising a second transformer connected in series with the first transformer,
The converter unit,
Inductors;
A first switching unit having a plurality of second switches connected to the inductor and the primary side of the first transformer; And
A second switching unit having a plurality of third switches connected to the primary side of the first switching unit and the second transformer,
The first switching unit and the second switching unit are connected in series with respect to the inductor, and one side of the secondary side of the second transformer is connected with a node between the first diode and the second diode, and the second And the other side of the secondary side of the transformer is connected to a node between the third diode and the fourth diode. 5. The output circuit of claim 4, wherein the inductor is charged when both the second switches and the third switches are turned on, and an output voltage is output from the rectifier when some of the second switches and the third switches are turned off. But
The magnitude of the output voltage is dependent on the ratio of the first time that both the second switches and the third switches are on and the second time when some of the second and third switches are off. Car charger. The method of claim 1, wherein the output voltage output from the rectifier when the rectifier is formed of the half bridge circuit is greater than the output voltage output from the rectifier when the rectifier is formed by the full bridge circuit. Car charger. The rectifier of claim 1, wherein the rectifier forms the full bridge circuit when a first current is input to the converter, and the rectifier is the half bridge circuit when a second current smaller than the first current is input to the converter. Form,
And an output voltage output from the rectifier when the rectifier is formed of the full bridge circuit and an output voltage output from the rectifier when the rectifier is formed by the half bridge circuit. A first transformer;
A second transformer; And
A converter unit connected to the primary side of the first transformer and having a first switching unit including a plurality of first switches and a second switching unit connected to the primary side of the second transformer and including a plurality of second switches; ,
And the first switching unit and the second switching unit are connected in series. The method of claim 8, wherein the converter unit further comprises an inverter,
The rectifying unit,
A first diode and a second diode connected in parallel to one end of the secondary side of the first transformer;
Third and fourth diodes connected in parallel to the other ends of the secondary side of the first transformer;
A third switch, one end of which is connected to a node between the third diode and the fourth diode, and the other end of which is connected to ground;
A first capacitor connected to one end of the secondary side of the first transformer and a node between the first diode and the second diode; And
A second capacitor connected to a node between the first diode and the third diode, wherein
The first switching unit and the second switching unit are connected in series with respect to the inverter, and the first to fourth diodes form the full bridge circuit, and the full bridge circuit is configured as the third switch is turned on. A vehicle charger, characterized by being switched to a half bridge circuit. 10. The method of claim 9, wherein the inductor is charged when both of the first and second switches are turned on, and an output voltage is output from the rectifier when some of the first and second switches are turned off. But
The magnitude of the output voltage is dependent on the ratio of the first time that the first switches and the second switches are both on and the second time when some of the first and second switches are off. Car charger. The rectifier of claim 9, wherein the rectifier forms the full bridge circuit when a first current is input to the converter, and the rectifier is the half bridge circuit when a second current smaller than the first current is input to the converter. Form,
And an output voltage output from the rectifier when the rectifier is formed of the full bridge circuit and an output voltage output from the rectifier when the rectifier is formed by the half bridge circuit. A converter unit; And
Including a rectifier for outputting an output voltage in response to the current output from the converter,
Even if the input power input to the converter unit is the same, the vehicle charger, characterized in that the magnitude of the output voltage varies according to the control signal for controlling the rectifier. The vehicle charger of claim 12, wherein the rectifier is switched from a full bridge circuit to a half bridge circuit or from the half bridge circuit to the full bridge circuit according to a control signal.

Images