DE102010024845B4 - High voltage generator - Google Patents

Abstract

High voltage generator (1), in particular for use as a disturbance frequency generator, comprising at least one piezo column (100) consisting of a number of "n" piezo elements (2) for converting mechanical pressure into electrical voltage and a load (4) functionally connected thereto. comprises, characterized in that the respectively adjacent piezoelectric elements (2) of the piezo-column (100) arranged electrically isolated from each other and the facing electrodes (6, 7) of adjacent piezoelectric elements (2) in each case via a spark gap (9) are interconnected.

Description

The invention relates to a high-voltage generator, in particular for use as a disturbance frequency generator, which comprises at least one consisting of a plurality n Piezo piezoelectric column for converting mechanical pressure into electrical voltage, wherein the number of piezoelectric elements is n> 3, and the voltage across at least one spark gap is short-circuited.

The increasing complexity of sensor technology, electronics, microelectronics in modern intelligent defense, communication and monitoring systems increases the performance of these systems, but on the other hand they can be very susceptible to electromagnetic fields of high power density due to their building properties (HPME - High Power Electromagnetics ). These sources, which can be used in practice, make it possible to disrupt or even destroy sensors and / or electronics with little collateral damage ( DE 103 42 730 A1 ).

In addition to explosives as an energy source ( DE 100 44 867 A1 ), the conversion of mechanical into electrical energy by means of piezoelectric ceramics is known. By pressure on such a ceramic electrical voltage is generated, the ceramic behaves like a simple charged ceramic capacitor. The energy density is an order of magnitude lower than in the explosive, but always sufficient for the given volume.

In such known high voltage generators, the piezoelectric elements are usually stacked arranged one above the other. In this case, the mutually facing electrodes of adjacent piezo elements are electrically conductively connected to each other, so that the piezo elements of the corresponding piezo column form a series circuit. Therefore, if pressure is exerted on the ends of the piezoelectric column, the result is a total voltage n × U ₀ , where U _{0 is} the peak value of the surge voltage generated by the individual piezoelectric element. Over a spark gap, which may be ignited or spark ignited, the stored energy in the piezoelectric elements then discharges into a load (for example, an antenna of the jammer).

As tests by the Applicant have shown, voltages of up to 250 kV can be generated by stacking serially connected piezo elements. Desirable or desirable, however, are voltages in the megavolt range.

From the DE 101 50 636 C2 a high voltage generator is known in which two piezoelectric columns are electrically connected in opposite directions in series via an electrically conductive coupling piece. In this case, electrodes extend from the front ends of the columns into the region of the coupling piece along the piezo columns and serve here as spark electrodes for spark gaps towards the coupling piece and between each other.

Also in this high-voltage generator, the two piezoelectric columns are formed by stacked piezoelectric elements, the electrodes of adjacent piezoelectric elements are electrically connected directly to each other, so in turn result series circuits with the disadvantages mentioned above.

The DE 29 13 448 A1 deals with a piezoelectric component with mounting plate for igniters. The piezoelectric component has four stacked piezoelectric elements, which are electrically separated from each other by insulating, so that there are four electrical terminals to which four ignition electrodes can be connected and which at the same time each give a spark.

With the DE 2 000 938 A a gas appliance with piezoelectric gas lighter is disclosed. Such gas lighters have a piezoelectric generator which generates electrical power by mechanical stress on its piezoelectric elements or its combination of piezoelectric elements. This is discharged in a spark that ignites the gas. According to the DE 2 000 938 A Two or more radio links will be rollovered simultaneously.

Based on this, the present invention seeks to provide a high voltage generator of the type mentioned, with the voltages can be generated by increasing the number of piezo elements over a value of 250 kV.

This object is achieved by the features of claim 1. Further, particularly advantageous embodiments of the invention disclose the dependent claims.

The invention is based essentially on the idea of making the stacking of the individual piezoelectric disks on the principle of a Marx generator. Since the pressed piezoelectric disks behave like charged ceramic capacitors, it is possible to discharge them like the capacitors in a Marx generator. - The DE 199 59 358 C2 describes an autonomous RF radiation source using a Marx generator, which successively generates a plurality of repetitive surge voltages and is successively radiated to the target via the UWB pulser and the broadband antenna. - The electrical circuit of the high voltage generator according to the invention thus resembles the circuit of a Marx generator for generating surge voltages. However, in the case of the Marx generator used here, a number of electrically parallel-connected capacitors are first charged and then connected in series at a predetermined time via spark gaps, in order to thereby generate a corresponding multiplication of the voltage.

In contrast, in the high voltage generator according to the invention no parallel charging of capacitances, but electrically isolated, but mechanically mutually parallel piezoelectric elements generate by exerting a correspondingly high pressure in each case a surge voltage with the peak value U ₀ . By igniting the spark gaps between the electrodes of adjacent piezoelectric elements, a corresponding multiplication of the voltage on the piezoelectric column as a function of the number of piezoelectric elements then takes place, similar to the Marx generator.

The main difference is that no charging of the individual capacitors by high voltage electrical is necessary, but that the piezoelectric disks are compressed by a high pressure within milliseconds. Since individual disks at the same pressure hold higher voltages than a stack of disks, the stack is constructed so that each disk is insulated from each other and only when reaching a maximum voltage value at each disk by spark gaps a series circuit is formed and the voltage thus depends on the number of discs multiplied. In contrast to the known high-voltage generators of the generic type, in the high-voltage generator according to the invention upon exercise of a corresponding pressure on the piezo column still no addition of the generated by the individual piezo elements surge voltages, but only when after reaching the switching voltage to the piezo column by igniting the spark gaps between the electrodes of adjacent piezoelectric elements, the individual piezoelectric elements electrically form a series circuit, the voltage on the piezoelectric column is multiplied correspondingly in dependence on the number of piezoelectric elements. Surprisingly, this process substantially improves the high-voltage strength of the piezoelectric column compared with known arrangements.

It is envisaged to electrically isolate each of the adjacent piezoelectric elements of a piezoelectric column from each other and to connect the mutually facing electrodes of adjacent piezoelectric elements each with its own spark gap, so that only after ignition of the spark gaps, a series connection of the piezoelectric elements and thus an increase in the total voltage results.

Advantageously, the high voltage is generated only for (very short) the period of time by being needed. At the same time it is possible to generate by the spark gaps at an inductance resonant transfer into a capacitive resonator with antenna. The voltage at the antenna is thus increased again, so that lower input voltages stronger HPEM pulses (HPEM: High Power Electromagnetics) can be generated.

More valuable details and advantages of the invention will become apparent from the following, explained with reference to a figure embodiment.

In the figure is with 1 denotes a high voltage generator. The high voltage generator 1 comprises one of a number n stacked piezo elements arranged 2 self-assembled piezo column 100 that have a first spark gap 3 with a load (antenna) 4 connected is. The number of piezo elements should be 2 "N" ≥ 3.

Each piezo element 2 includes a part 5 of a piezoelectric material (for example a ceramic), on the two opposite electrodes 6 . 7 are applied.

Adjacent piezo elements 2 of the high voltage generator 1 are electrically spaced from each other by an insulating washer 8th separated. The two are separated by an insulating disc electrodes 6 . 7 adjacent piezo elements 2 electrically via a second spark gap 9 connected with each other. In addition, the electrodes 6 via a discharge resistor 10 with mass 11 of the high voltage generator 1 connected.

Will now be in the direction of with 12 indicated arrow pressure on the "n" stacked piezoelectric elements exercised, it follows at the electrodes 6 . 7 each of the piezo elements 2 a surge voltage with the peak value U ₀ .

Now ignite a spark gap 9 , one or more of which may be ignited externally, the voltage of the next piezoelectric element shifts so that an addition takes place. The voltage increases at the following (second) spark gap 9 abruptly. A chain reaction sets in and within nanoseconds all spark gaps 9 switched through and the maximum voltage of the entire stack of n piezo elements 2 is U _ges = n × U ₀ .

The total energy stored in the electric field now discharges via the spark gap 3 in the load 4 ,

By a clever choice of inductance in the supply line to the load 4 is it possible the voltage at the load 4 in addition to increase, so that it is possible to achieve a voltage U _L > U _ges .

The pressure on the disc package 100 is freely selectable upwards, whereby the dielectric strength of the individual elements / slices 2 and the mechanical compressive strength must be taken into account. An increase in the energy content of the system can - regardless of the number of slices and / or the constant pressure on the discs 2 - Be made in addition by increasing the maximum open circuit voltage U ₀ . This depends on the piezoelectric voltage constants, the pressure and the distance between the electrodes.

LIST OF REFERENCE NUMBERS

1

High voltage generator

2

piezo element

3

(first) spark gap

4

load

5

part

6, 7

electrodes

8th

insulating

9

(second) spark gap

10

discharge

11

Dimensions

12

arrow

100

Piezo column

Claims (6)

High voltage generator ( 1 ), in particular for use as a disturbance frequency generator, the at least one of a number of "n" piezo elements ( 2 ) existing piezo column ( 100 ) for converting mechanical pressure into electrical voltage and a functionally connected load ( 4 ), characterized in that the respectively adjacent piezo elements ( 2 ) of the piezo column ( 100 ) electrically isolated from each other and the facing electrodes ( 6 . 7 ) of adjacent piezo elements ( 2 ) each over a spark gap ( 9 ) are interconnected. High-voltage generator according to claim 1, characterized in that for the isolation of adjacent piezo elements ( 2 ) between these in each case an insulating disk ( 8th ) is arranged. High-voltage generator according to claim 1 or 2, characterized in that the connection of an electrode ( 7 ) each of the piezo elements ( 2 ) via a resistor ( 10 ) he follows. High-voltage generator according to one of claims 1 to 3, characterized in that the piezoelectric elements ( 2 ) consist of piezoelectric ceramic. High-voltage generator according to one of claims 1 to 4, characterized in that the number of piezo elements ( 2 ) n> 3. High-voltage generator according to one of claims 1 to 5, characterized in that the stacking of the individual piezoelectric elements ( 2 ) takes place on the principle of a Marx generator.

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