KR20150081915A - Power conversion device - Google Patents

Abstract

An embodiment of the present invention provides an apparatus for converting the power comprising: a power switch part which supplies and cuts off a first DC power inputted; a voltage reducing part which stores current energy when the first DC power is supplied from the power switch part, outputs the first DC power to a load by reducing voltage to a second DC power and outputs the current energy to the load when the first DC power is cut off from the power switch part; a smoothing part which performs smoothing of the current energy; and a protecting part which cuts off the first DC power inputted to a switch element when the second DC power detected in the voltage reducing part is higher than the reference power and discharges the second DC power to the ground.

Description

Power conversion device

The present invention relates to a power conversion apparatus, and more particularly, to a power conversion apparatus that can easily reduce an input first dc power source to a second dc power source.

In general, a converter is a device for converting an input voltage and outputting it to a desired voltage. The type of a converter is an AC-DC converter that receives an AC input and converts it to DC, and outputs an AC-DC converter. A direct current-to-DC converter that converts the DC voltage to a desired DC voltage and then outputs the DC voltage.

In particular, DC-DC converters are widely used in SMPS (switched-mode power supply), DC motor control, and battery charging devices.

In such a DC-DC converter, a non-isolating converter in which an input part for receiving a voltage and an output part for outputting a voltage are not electrically insulated, an input part for receiving a voltage, and an output part for outputting a voltage are electrically insulated And an isolating converter.

The non-isolated converter includes a buck converter with a voltage drop method, a boost converter with a boost method, and a Cuk converter with a voltage drop and a boost. The isolation converter includes a flyback converter and a forward converter.

In the case of such a DC-DC converter, an excessive voltage is supplied to a load by a malfunction of a switch for converting a DC voltage to a pulse voltage at an input part, so that research for preventing an excessive voltage from being supplied to the load is progressing have.

It is an object of the present invention to provide a power conversion apparatus which is easy to reduce an input first dc power source to a second dc power source and is easy to prevent an excessive second dc power source from being applied to a load.

The power conversion apparatus according to an embodiment of the present invention includes a power switch unit for supplying and blocking an input first dc power, a second dc power source for storing current energy when the first dc power is supplied from the power switch unit, a smoothing unit for smoothing the current energy output from the decompression unit and outputting the current energy to the load when the first dc power is cut off from the power switch unit; And a protection unit that cuts off the first dc power supplied to the switch element when the second dc power detected by the pressure reducing unit is higher than the set reference power, and discharges the second dc power to the ground.

When the power switch element for performing the switching-on operation to supply the first dc power source to the decompression portion fails to perform the switching-off operation due to a failure, the second dc power output from the decompression portion becomes excessively high, If the second dc power supply is higher than the set reference power supply, the first dc power supply is cut off so that the first dc power supply is not supplied to the power supply switch element, thereby preventing damage to the load.

1 is a circuit diagram showing a power conversion apparatus according to an embodiment.
FIG. 2 is a circuit diagram showing a power supply path in the switching-on operation of the power switch element shown in FIG.
3 is a circuit diagram showing a power supply path in the switching-off operation of the power switch element shown in FIG.
4 is a waveform diagram showing power waveforms at the first to third nodes and the fifth node among the power path paths shown in FIGS. 2 and 3. FIG.
5 is a circuit diagram showing a power supply path according to a protection section operation when the power supply switch element shown in FIG. 2 fails.
6 is a waveform diagram showing power supply waveforms at the third and fourth nodes of the power supply path shown in FIG.

The following merely illustrates the principles of the invention. Therefore, those skilled in the art will be able to devise various apparatuses which, although not explicitly described or shown herein, embody the principles of the invention and are included in the concept and scope of the invention. It is also to be understood that all conditional terms and examples recited in this specification are, in principle, expressly intended for the purpose of enabling the inventive concept to be understood and are not to be construed as limited to such specifically recited embodiments and conditions do.

It is also to be understood that the detailed description, as well as the principles, aspects and embodiments of the invention, as well as specific embodiments thereof, are intended to cover structural and functional equivalents thereof. It is also to be understood that such equivalents include all elements contemplated to perform the same function irrespective of the currently known equivalents as well as the equivalents to be developed in the future, i.e., the structure.

Thus, for example, it should be understood that the block diagrams herein illustrate exemplary conceptual aspects embodying the principles of the invention. Similarly, all flowcharts, state transition diagrams, pseudo code, and the like are representative of various processes that may be substantially represented on a computer-readable medium and executed by a computer or processor, whether or not the computer or processor is explicitly shown .

The functions of the various elements shown in the figures, including the functional blocks depicted in the processor or similar concept, may be provided by use of dedicated hardware as well as hardware capable of executing software in connection with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared.

Also, the explicit use of terms such as processor, control, or similar concepts should not be interpreted exclusively as hardware capable of running software, and may be used without limitation as a digital signal processor (DSP) (ROM), random access memory (RAM), and non-volatile memory. Other hardware may also be included.

In the claims of the present specification, the elements represented as means for performing the functions described in the detailed description may include, for example, a combination of circuit elements performing the function or any type of software including firmware / And is coupled with appropriate circuitry for executing the software to perform the function. It is to be understood that the invention as defined by the appended claims is not to be interpreted as limiting the scope of the invention as defined by the appended claims, as the functions provided by the various enumerated means are combined and combined with the manner in which the claims require. .

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: . In the following description, a detailed description of known technologies related to the present invention will be omitted when it is determined that the gist of the present invention may be unnecessarily blurred.

1 is a circuit diagram showing a power conversion apparatus according to an embodiment.

Referring to FIG. 1, the power conversion apparatus may include a buck converter unit 110 and a protection unit 120.

Here, the buck converter 110 reduces the first dc power source Vdc_1 input to the first node n1 to the second dc power source Vdc_2 and outputs the reduced voltage to the load (not shown) through the fifth node n5 do.

The buck converter 110 includes a power switch unit VSW for supplying and blocking a first dc power source Vdc_1 input to the first node n1, When the 1 dc power source Vdc_1 is supplied, the first dc power source Vdc_1 stores the current energy and outputs the first dc power source Vdc_1 to the load via the third to fifth nodes n3 to n5. (L) for outputting the stored current energy to the third to fifth nodes (n3 to n5) when the first dc power source (Vdc_1) is not supplied to the second node (n2) A smoothing unit C for storing and smoothing the output current energy and a diode D constituting a closed circuit with the depressurizing unit L and the smoothing unit C in the current energy output in the depressurizing unit L do.

That is, the power switch unit VSW switches on the first dc power source Vdc_1 input to the first node n1 and outputs the first dc power source Vdc_1 to the second node n2. In the switch-on operation, A power switch element VQ and a power switch element VQ for supplying a ground power (not shown) to the second node n2 by interrupting supply of the first dc power source Vdc_1 input to the node n1, And a switch control element SC for controlling the switching element SC to be turned off.

Here, the power switch element VQ may be a field effect transistor (MOSFET), or may be another element controlled by a pulse width modulation method, but is not limited thereto.

The switch control element SC detects the second dc power supply Vdc_2 output from the reduced voltage section L at the third node n3 and compares the second dc power supply Vdc_2 output from the third node n3 with the set power supply, And controls the operation.

That is, when the second dc power source Vdc_2 is lower than the set power source, the switch control element SC delivers a switch-on signal (not shown) so that the power source switch element VQ is switched on and the second dc power source (Not shown) so that the power switch element VQ is switched off when the voltage Vdc_2 is higher than the set power.

Here, the switch control element SC can control the operation time related to the switching-on operation of the power switch element VQ and the operation time related to the switching-off operation, that is, the pulse width of the switch-on signal and the switch- have.

That is, the switch control element SC switches the first dc power source Vdc_1 of the DC type inputted to the first node n1 to the second node n2 by switching on and off the power switch element VQ (Not shown) composed of a 1-dc power supply Vdc_1 and a ground power supply (not shown).

The depressurizing unit L outputs the first dc power source Vdc_1 inputted to the second node n2 to the third dc power source Vdc_2 reduced to the counter electromotive force to the third node n3, Vdc_1).

Here, the pressure-reducing portion L is an inductor, and is not limited thereto.

The depressurization unit L outputs the stored current energy to the third node n3 when the first dc power source Vdc_1 is not input to the second node n2 or when the ground power source is input.

The smoothing unit C has a second dc power source Vdc_2 input to the fifth node n5 through the third node n3 and a second dc power source Vdc_2 having a constant current energy, do.

Here, the smoothing portion C is a capacitor, and is not limited thereto.

That is, the decompression unit L and the smoothing unit C are LC filters used as a low pass filter made up of a resonant circuit, and the first dc power source Vdc_1 is filtered by the second dc power source Vdc_2 can do.

As described above, the buck converter 110 can supply the load with the second dc power source Vdc_2 that reduces the input first dc power source Vdc_1.

The protection unit 120 may include a comparator OP-amp, a switching device AQ, a protection switching device CQ, and a discharging switching device SCR.

The comparator OP-amp is a comparator OP-amp that is supplied with the second dc power source Vdc_2 supplied from the sixth node n6 between the switch control element SC and the third node n3, (-) to which a non-inverting terminal (+) and a reference power supply (Vg) to which a voltage (referred to as a "second dc power supply" hereinafter) And may be a comparator (OP-amp) that compares the voltage divided by the second dc power source Vdc_2 and the voltage divided by the reference power source Vg.

The comparator OP-amp compares the second dc power supply Vdc_2 with the reference power supply Vg and outputs a first signal (not shown) when the second dc power supply Vdc_2 is lower than the reference power supply Vg And outputs a second signal (not shown) if the second dc power supply Vdc_2 is higher than the reference power supply Vg.

The switch element AQ is connected to the output terminal of the comparator OP-amp and includes a gate terminal (not shown) to which one of the first and second signals is inputted, a drain terminal And a source terminal (not shown) for outputting the reference power source Vg to the protection switch element CQ and the discharge switch element SCR.

In an embodiment, the switching element AQ is represented and described as a pn junction transistor (BJT), but may be a field effect transistor and is not limited thereto.

That is, the switch element AQ is operated to switch off when the first signal is input, so that the protection switch element CQ is kept in the switch-on state. When the second signal is input, 7 node n7 to the protection switch element CQ and the discharge switch element SCR.

The protection switch element CQ is connected to the first dc power supply Vdc_1 supplied to the first node n1 when the reference power supply Vg is inputted through the switch element AQ, that is, the seventh node n7, Lt; / RTI >

That is, when the reference power supply Vg is not inputted, the protection switch element CQ maintains the switch-on operation and can supply the first dc power supply Vdc_1 to the first node n1.

The protective switch element CQ is configured such that when a failure occurs in the power switch section VSW, the overvoltage higher than the second dc power supply Vdc_2 is supplied to the load when the power switch element VQ maintains the switching on operation state The first dc power source Vdc_1 input to the power switch element VQ is cut off.

When the reference power supply Vg is inputted from the seventh node n7, the discharge switch element SCR is turned on to discharge the second dc power supply Vdc_2 inputted to the fourth node n4 to the ground have.

That is, the discharge switch element SCR may be a silicon controlled rectifier, but is not limited thereto.

The power conversion apparatus according to the embodiment may be configured such that the second dc power source Vdc_2 that reduces the input first dc power source Vdc_1 is connected to the power source switch unit 110 included in the buck converter 110 A failure occurs and the power switch element VQ keeps on the switching on operation to prevent the second dc power source Vdc_2 from rising in the depressurizing portion L through the protection portion 120, There is an advantage that breakage can be prevented.

FIG. 2 is a circuit diagram showing a power path of the power switch element shown in FIG. 1, and FIG. 3 is a circuit diagram of a power path of the power switch element of FIG. 3 is a waveform diagram showing power waveforms at the first to third nodes and the fifth node among the power path paths shown in FIG. 3; FIG.

2 is a schematic diagram illustrating a power supply path (1) output from a load (not shown) by reducing the input first dc power source (Vdc_1) to a second dc power source (Vdc_2) during normal switching on operation of the power switch element (VQ) .

That is, the power path (1) shown in FIG. 2 is connected to the load through the protective switch element CQ, the power switch element AQ, and the depressurizing part L to which the first dc power source Vdc_1 is input, And the power supply Vdc_2.

Here, when the reference voltage Vg is not inputted when the comparator OP-amp operates, the switching element AQ is switched on and the reference voltage Vg is supplied to the protection switch element CQ, On operation and outputs the first dc power Vdc_1 to the first node n1 through the power switch AQ.

That is, as shown in Fig. 4, the first node n1 is supplied with the first dc power source Vdc_1 during the switching-on operation of the protection switch element CQ.

At this time, the power switch element VQ is switched on under the control of the switch control element SC to switch the first dc power source Vdc_1 inputted from the first node n1 to the second node n2 .

4, the second node n2 is supplied with the first dc power source Vdc1 when the power switch element VQ is switched on, and the power source switch element VQ is turned on in Fig. 3 And is maintained until the switching-off operation.

The depressurizing unit L then outputs the second dc power source Vdc2 that has been reduced to the first dc power source Vdc1 input to the second node n2 to the load through the fifth node n5, It is possible to store the current energy corresponding to the 1 dc power supply Vdc.

That is, as shown in Fig. 4, the third and fifth nodes n3 and n5 output the second dc power source Vdc_2, which is depressurized through the depressurization portion L, to the load.

3 is a view showing a power supply path (2) output from a load (not shown) by reducing the input first dc power source Vdc_1 to the second dc power source Vdc_2 in the normal switching off operation of the power switch element VQ, .

That is, the power path (2) shown in FIG. 3 is connected to the load through the protective switch element CQ, the power switch element AQ and the depressurizing part L to which the first dc power source Vdc_1 is input, And the power supply Vdc_2.

The switch control element SC detects the second dc power source Vdc_2 at the third node n3 in Fig. 2 and the power switch element AQ is switched off according to the duration of the second dc power source Vdc_2 Respectively.

That is, the power path (2) is a power path after the power switch element VQ is switched off by the switch control element SC.

The decompression unit L constitutes a closed circuit by the smoothing unit C and the diode D when the power switch element VQ is switched off and outputs the stored current energy to the load through the fifth node n5 do.

At this time, the fifth node n5 shown in FIG. 4 is turned off during the switching-off operation of the power switch element VQ from the second dc power supply Vdc_2 output during the switching on operation of the power switch element VQ, The smoothed power source, that is, the second dc power source Vdc_2 close to the direct current is outputted by the part C.

Therefore, as shown in FIGS. 2 and 3, the power conversion apparatus includes a second dc power source Vdc_2 that is obtained by reducing the first dc power source Vdc_1 input by the power-on switching element VQ in the switching-on operation and the switching- Can be output to the load.

FIG. 5 is a circuit diagram showing a power supply path according to the operation of the protection unit when the power supply switch element shown in FIG. 2 fails; and FIG. 6 is a waveform diagram showing power supply waveforms at the third and fourth nodes in the power supply path shown in FIG. .

5 is a graph showing the relationship between the current energy stored in the depressurization unit L and the current stored in the depressurization unit L when the protection unit 120 is operated in the case where the power switch element VQ maintains the switching on operation due to a failure at the switching- And the power path (3).

That is, the power path (3) shown in FIG. 5 is a power supply path (3) in which the first dc power source (Vdc_1) is reduced in the depressurization portion (L) The second dc power source Vdc_2 raised to the first dc power source Vdc_1 during the output of the second dc power source Vdc_2 can be output.

The third node n3 shown in FIG. 6 outputs the second dc power source Vdc_2 whose power source switch element VQ is in the normal switching-on operation and the power source switch element VQ It is found that the second dc power source Vdc_2 is increased by the first dc power source Vdc_1 at the first point A in the switching on operation.

At this time, the comparator OP-amp detects the second dc power source Vdc_2 raised at the third node n3 and compares it with the set reference power source Vg.

The comparator OP-amp switches on the switch element AQ when the second dc power supply Vdc_2 is higher than the reference power supply Vg at the first point A shown in Fig. 6, CQ and supplies the reference power source Vg so that the discharge switch element SCR is switched on.

The protective switch element CQ is turned off to cut off the first dc power source Vdc_1 input to the power switch element VQ.

Therefore, the power supply path (3) is connected to the second dc (4) output from the reduced voltage portion L to the third and fourth nodes (n3 and 4) as the protection switch element (CQ) and the discharge switch element The power source Vdc_2 can be discharged through the discharge switch element SCR.

Here, the third node n3 shown in Fig. 6 determines that the second dc power source Vdc_2 is raised at the first point A of the comparator OP-amp, The element AQ is switched on to switch off the protection switch element CQ to cut off the input of the first dc power source Vdc_1 to the power switch element VQ and turn on the discharge switch element SCR It is possible to discharge the current energy stored in the depressurization unit L, that is, the current energy such as the third point C.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: Buck converter 120:

Claims (13)

A power switch unit for supplying and cutting off the input first dc power;
Wherein when the first dc power is supplied from the power switch unit, current energy is stored, and the first dc power source is decompressed to a second dc power source to output the reduced current to the load, A decompression unit outputting current energy to the load;
A smoothing unit for smoothing the current energy output from the decompression unit; And
And a protective unit for shutting off the first dc power supplied to the switch element and discharging the second dc power to the ground when the second dc power detected by the pressure reducing unit is higher than the set reference power, Device. The method according to claim 1,
The power switch unit includes:
A power switch element for switching on and off the first dc power supply to be supplied and cut off; And
And a switch control element which compares the set power source set by the second dc power output from the pressure reducing unit and controls the switch on and off operation of the power switch element. 3. The method of claim 2,
Wherein the power switch element comprises:
A power conversion device that is a field effect transistor (MOSFET). 3. The method of claim 2,
The switch control element includes:
When the second dc power source is lower than the set power source, a switch-on signal is transmitted so that the power source switch element is switched on, and when the second dc power source is equal to or higher than the set power source, A power converter for delivering a switch-off signal. 5. The method of claim 4,
The switch control element includes:
And modulates a pulse width of the switch-on signal and the switch-off signal to adjust an operation time for switching on and off operations of the power switch element. The method according to claim 1,
The pressure-
And generates an inverse electromotive force when the first dc power is input to reduce the voltage to the second dc power. The method according to claim 1,
The smoothing unit includes:
And a capacitor for smoothing a peak of the current energy output from the decompression unit when the power switch element starts switching off operation after switching on. The method according to claim 1,
Wherein the pressure-reducing portion and the smoothing portion comprise:
A power transformer that is an LC filter (low pass filter). The method according to claim 1,
The protection unit includes:
A comparator that outputs a first signal when the second dc power source is lower than the reference power source and outputs a second signal when the second dc power source is higher than the reference power source;
A switch element for switching off when the first signal is input and switching on when the second signal is input to output the reference power;
A protection switch element for switching on and off when the reference power is not inputted and for turning off the first dc power supplied to the power switch part when the reference power is inputted; And
And a discharge switch element for performing a switching-off operation when the reference power source is not input, and for discharging the second dc power source output from the reduced-pressure portion to the ground when the reference power source is input. 10. The method of claim 9,
The comparator comprising:
(OP-amp) that compares the second dc power source and the reference power source to output any one of the first and second signals. 10. The method of claim 9,
The switch element includes:
PN junction transistor. 10. The method of claim 9,
The protection switch element includes:
A power conversion device that is a field effect transistor. 10. The method of claim 9,
The discharge switch element
A power conversion device that is a silicon controlled rectifier.

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