KR101464668B1 - Energy recovery apparatus for driving piezo - Google Patents

Abstract

According to the present invention, an energy recovery device for driving a piezoelectric element includes: the piezoelectric element; a H bridge circuit which drives the piezoelectric element; and a energy recovery circuit which reduces electric currents by transmitting charges of the piezoelectric element from a side to the other side. According to the present invention, a simplified driving circuit in which only two switches and an inductor are added to recover energy used for driving an inverter of the piezoelectric element can be formed. The amount of electric power applied can be minimized by dividing switching operation into switching operation for recovery and switching operation for applying supplied electric power. Therefore, the energy recovery device can substantially contribute to saving electric power and costs.

Description

[0001] The present invention relates to an energy recovery apparatus for driving a piezoelectric device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy recovery circuit, and more particularly, to an energy recovery device for driving a piezoelectric element which satisfies an asymmetric voltage drive characteristic for driving a piezoelectric element.

In general, the energy recovery system is mainly applied to PDP (Plasma Display Panel) drive. By implementing a number of switches, inductors, diodes and capacitors for energy recovery outside the basic H bridge circuit, The recovery circuit is more complex.

In other words, all of the energy stored in the capacitor is released and the switch on-off is regulated so that the voltage is applied again in the reverse direction. For four basic switches for the H bridge, two switches, eight diodes and capacitors Or 4 switches and two switching transformers are added, which complicates the circuit configuration, resulting in an increase in cost and an increase in volume.

In some cases, two switches and one inductor are added. However, three switches operate at the same time, so that the switching loss is relatively large and the switching method is more complicated.

In addition, the general energy recovery circuit is intended for a PDP (Plasma Display Panel) power supply circuit and can not satisfy the asymmetric voltage drive characteristic for driving the piezoelectric element.

A diagram showing such an H-bridge inverter circuit is shown in Fig. 1, the piezoelectric element 170 is represented by a resistor-capacitor disposed between the switches 100 and 130 in the H bridge and the switches 120 and 140.

When the switches 110 and 140 are turned on in the H bridge inverter, the voltages are applied to the first load terminal 150 and the second load terminal 160, respectively. When the switches 110 and 140 are turned off and the switches 120 and 130 are turned on to apply the reverse voltage, the second load terminal 160 is now +, the first load terminal 150 is turned on, and a reverse voltage is applied to the load .

At this time, the load, together with the power supply voltage, is added to the voltage when the forward voltage is applied, so that twice the power supply voltage is applied to the load, so that a very large current flows momentarily until the capacitor is completely reversed.

At this moment, the power is multiplied by the applied voltage and the large current flowing instantaneously, consuming a very large reactive power. This again means that a power source capable of supplying such power is required.

1. Korean Patent Publication No. 10-2008-0086749 2. Korean Patent Publication No. 10-2008-0105751 3. Korean Patent Publication No. 10-2007-0038411 4. Korean Patent Publication No. 10-2000-0040964

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above problems, and it is an object of the present invention to provide an energy recovery device for driving a piezoelectric element, which is simple and miniaturized and lightweight and / or cost- .

It is another object of the present invention to provide an energy recovery device for driving a piezoelectric element which satisfies such a case even when a normal / reverse asymmetric voltage is required, such as a piezoelectric element.

In order to achieve the above-described problems, the present invention provides an energy recovery apparatus for driving a piezoelectric element, which is simple and miniaturized and lightweight and / or cost-saving while minimizing the capacity of an applied power source.

In the piezoelectric element driving energy recovery device,

A piezoelectric element driving energy recovery device having a piezoelectric element and an H-bridge circuit for driving the piezoelectric element,

And an energy recovery circuit portion for transferring the charge of the piezoelectric element from one side to the other side to reduce the current of the driving power source.

On the other hand, another embodiment of the present invention is a piezoelectric element driving energy recovery device having a piezoelectric element and an H-bridge circuit for driving the piezoelectric element, wherein (+) and (- A pair of power sources of different magnitudes driving voltages of different magnitudes; And an energy recovery circuit part for transferring the electric charge of the piezoelectric element from one side to the other side to reduce the current of the driving power source.

A diode connected in series to a smaller one of the pair of power supplies; And

And a storage capacitor connected in parallel to the diode to store surplus energy at the time of regeneration.

And a storage capacitor connected in parallel to the smaller one of the pair of the power sources to store surplus energy in cooperation with the smaller power source during regeneration.

The energy recovery circuit unit may further include: a plurality of switches disposed at both ends of the piezoelectric element; And an inductor connected in series between the plurality of switches.

The plurality of switches may be characterized in that currents in both directions are opened and closed by using a power switching element having a parasitic diode.

The plurality of switches may be driven so as to be ahead of the phase, and the phase of the driving for supplementing the power supply may be delayed.

In addition, the piezoelectric element may include a capacitor and a resistor connected in series.

According to the present invention, it is possible to realize a simplified drive circuit in which only two switches and an inductor are added by performing energy recovery when driving an inverter of a piezoelectric element, and the switch operation is also performed for switching operation for energy recovery and supply of power Switching operation, so that the capacity of the power supply is minimized, which contributes greatly to the reduction in size and weight of the power supply and the cost reduction.

Another effect of the present invention is that, when a normal / reverse asymmetric voltage is required as in the case of a piezoelectric element, an asymmetrical inverter can be constructed by adding a power source suitable for an inverse voltage, thereby protecting the property of the piezoelectric element .

1 shows an H-bridge inverter circuit for driving a general piezoelectric element.
2 is a circuit diagram of an energy recovery apparatus 200 for driving a piezoelectric element according to an embodiment of the present invention.
3 is a switching operation waveform diagram showing a driving method of the energy recovery apparatus 200 shown in FIG.
4 is a circuit diagram of a piezoelectric element driving energy recovery apparatus 300 for applying a normal / reverse asymmetric voltage according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

Hereinafter, an energy recovery device for driving a piezoelectric element according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a circuit diagram of an energy recovery apparatus 200 for driving a piezoelectric element according to an embodiment of the present invention. 2, the piezoelectric element driving energy recovery apparatus 200 includes a piezoelectric element 270, an energy recovery circuit unit 280 connected to both ends of the piezoelectric element 270, Switches 210, 220, 230 and 240 connected to both ends of the both ends and the energy recovery circuit unit 280, a power source 201, and the like.

The piezoelectric element 270 is disposed between a pair of switches 210 and 230 in the H bridge circuit (or H bridge inverter circuit) and a pair of switches 220 and 240, and is represented by a series connection of the resistor-capacitors. That is, the pair of switches are serially connected as the first switch 210 and the third switch 230, and the other pair of switches are serially connected as the second switch 220 and the fourth switch 240 .

A first load terminal 250 and a second load terminal 260 are connected to the middle of the pair of switches and a piezoelectric element 270 is connected between the first load terminal 250 and the second load terminal 260. [ Lt; / RTI >

An energy recovery circuit unit 280 is connected to both ends of the piezoelectric element 270. The energy recovery circuit unit 280 includes a first energy recovery switch 282, an inductor 281, a second energy recovery switch 283, Lt; / RTI >

As the switches 210, 220, 230, 240, 282, and 283, a power switching device having a parasitic diode is used, and an IGBT (Insulated Gate Transistor), a power MOSFET (Metal Oxide Silicon Field Effect Transistor)

The piezoelectric element 270 is configured by connecting a load capacitor 271 and a load resistor 272 in series.

3 is a switching operation waveform diagram showing a driving method of the energy recovery apparatus 200 shown in FIG. Referring to FIG. 3, the first and fourth switches 210 and 240 are turned on, and a forward voltage is applied to the first load terminal 250. When the phase of the applied power source is 180 degrees, the first and fourth switches 210 and 240 are turned off and the first recovery circuit switch 282 is turned on first.

만큼 지연 후 다시 제 2 및 제 3 스위치(220,230)를 on시켜서, 부하 저항(272)이 소모한 만큼 부족한 에너지를 전원(201)으로부터 공급한다.From this, the energy of the load capacitor 271 is charged to the load capacitor 271 through the inductor 281 in the opposite polarity,

The second and third switches 220 and 230 are turned on again to supply the energy from the power source 201 as much as the load resistance 272 consumes.

When the voltage is further increased by 180 degrees, the polarity of the load capacitor 271 is charged again in the opposite direction.

4 is a circuit diagram of a piezoelectric element driving energy recovery apparatus 400 for applying a normal / reverse asymmetric voltage according to another embodiment of the present invention. 4, the piezoelectric element driving energy recovery apparatus 400 includes a piezoelectric element 470, an energy recovery circuit unit 480 connected to both ends of the piezoelectric element 470, Switches 410, 420, 430 and 440 connected to both ends of both ends and the energy recovery circuit unit 480 and a pair of power sources 401 and 402 connected to both ends of the switches 410, 420, 430 and 440.

The piezoelectric element 470 is disposed between a pair of switches 410 and 430 in the H bridge circuit (or H bridge inverter circuit) and a pair of switches 420 and 440, and is represented by a series connection of the resistor-capacitors. That is, the pair of switches is serially connected as the first switch 410 and the third switch 430, and the other pair of switches is serially connected as the second switch 420 and the fourth switch 440 .

An energy recovery circuit portion 480 is connected to both ends of the piezoelectric element 470. The energy recovery circuit portion 480 is configured such that the first energy recovery switch 482, the inductor 481, and the second energy recovery switch 483 are connected in series Lt; / RTI >

As the switches 410, 420, 430, 440, 482, 483, a power switching element having a parasitic diode is used, and an IGBT (Insulated Gate Transistor), a power MOSFET (Metal Oxide Silicon Field Effect Transistor)

In addition, the pair of power supplies 401 and 402 are driven with different magnitudes of positive and negative voltages for protecting the piezoelectric element 470. That is, the voltage magnitude of the first power source 401 is greater than the voltage magnitude of the second power source 402.

On the other hand, a diode 491 connected in series to the second power source 402 having a small voltage magnitude and a capacitor 492 connected in parallel to the diode 491 to store surplus energy during regeneration are formed.

만큼 지연 후 다시 제 2 및 제 3 스위치(420,430)를 on시켜서 제 2 전원 Vs2(402)가 부하에 전압을 공급하게 된다. 3, and when the reverse voltage is applied, the first recovery circuit switch 482 is turned on,

The second and third switches 420 and 430 are turned on again so that the second power source Vs2 402 supplies the load with the voltage.

That is, in FIG. 4, the diode 491 is connected in series to the second power source 402, which is the smaller power source, and the storage capacitor 492 is connected in parallel to the diode connected in series with the power source 402, Lt; RTI ID = 0.0 > capacitors. ≪ / RTI >

Meanwhile, according to another embodiment of the present invention, it is also possible to remove the diode 491 connected in series and store the surplus energy jointly when the storage capacitor 492 and the power source 402 are regenerated.

101: Power supply
110, 120,
150: first load terminal 160: second load terminal
170: piezoelectric element
200,300: Energy recovery device for driving piezoelectric elements
201: Power supply
210, 220, 230, 240:
250: first load terminal 260: second load terminal
270: piezoelectric element
271: Load capacitor 272: Load resistance
280: Energy recovery circuit part
281: Inductor 282: First recovery circuit switch
283: Second recovery circuit switch
401,402: Power
410, 420,
470: piezoelectric element
491: Diode
492: Storage capacitor

Claims (8)

delete A piezoelectric element driving energy recovery device having a piezoelectric element and an H-bridge circuit for driving the piezoelectric element,
A pair of power sources different in magnitude for driving the magnitudes of the (+) and (-) voltages to protect the piezoelectric element; And
And an energy recovering circuit part which flows the energy of the piezoelectric element through the inductor to the piezoelectric element itself and the piezoelectric element is charged with the opposite polarity of the application power source for driving the piezoelectric element to recover the energy without discharging the energy Wherein the energy recovery device comprises:
3. The method of claim 2,
A diode connected in series to a power source having a relatively small voltage of the pair of power sources; And
And a storage capacitor connected in parallel to the diode to store surplus energy at the time of regeneration.
3. The method of claim 2,
And a storage capacitor connected in parallel to the power source having a relatively small voltage among the pair of power sources and storing surplus energy in cooperation with the smaller power source when the power source is regenerated. Device.
3. The method of claim 2,
The energy recovery circuit unit includes:
A plurality of switches disposed at both ends of the piezoelectric element; And
And an inductor connected in series between the plurality of switches.
3. The method of claim 2,
Wherein a plurality of switches disposed at both ends of the piezoelectric element open / close currents in both directions using a power switching element having a parasitic diode.
3. The method of claim 2,
Wherein a plurality of switches disposed at both ends of the piezoelectric element are driven to be higher in phase than a plurality of switches connected to the power source and disposed in the H bridge circuit, Wherein a plurality of switches connected to a power source are driven to be delayed in phase from a plurality of switches disposed at both ends of the piezoelectric element.
3. The method of claim 2,
Wherein the piezoelectric element includes a capacitor and a resistor connected in series.

Images