CONVERTER AND POWER DEVICE WITH SUCH A CONVERTER

Abstract

The invention relates to a converter (10), especially for use at high voltage ratios, characterized by a cascade of at least two steps, wherein at least the first step is made of a resonant unit (15), which comprises at least one inductive reactance unit, in particular at least one piezoelectric resonator, and at least one capacitor unit, which are connected in series.

Claims

1. Converter (10), especially for use at high voltage ratios, characterized by a cascade of at least two steps, wherein at least the first step is made of a resonant unit (15), which comprises at least one inductive reactance unit, in particular at least one piezoelectric resonator, and at least one capacitor unit, which are connected in series.

2. Converter (10) according to claim 1, characterized in that the second step is made of a resonant unit (16), which comprises at least one inductive reactance unit, in particular at least one piezoelectric resonator, and at least one capacitor unit connected in series.

3. Converter (10) according to claim 1, characterized in that the piezoelectric resonator is made of lead zirconium titanate.

4. Converter (10) according to claim 1, characterized in that a high-level port of an elementary resonant unit (15, 16) is formed between a conductor and the common ground, wherein the conductor links the inductive reactance unit and the capacitor unit of the resonant unit (15, 16), wherein a low-level port is formed between the remaining open side of the elementary resonant unit (15, 16) and the ground, and wherein the at least two resonant units (15, 16) are connected in cascade through their input ports and output ports.

5. Converter (10) according to claim 1, characterized in that at least one resonant unit (15, 16) is made of an arrangement of identical components which are connected in series and/or in parallel.

6. Converter (10) according to claim 1, characterized in that the inductive reactance units and the capacitor units of the at least two resonant units are made of identical components which are arranged in different manners.

7. Converter (10) according to claim 1, characterized in that the at least two resonant units (15, 16) comprise the same number of components.

8. Converter (10) according to claim 1, characterized in that an inductive reactance unit and/or a capacitor unit is/are formed of a coil or a capacitor or a piezoelectric resonator or a dielectric resonator or a transmission line.

9. Converter (10) according to claim 1, characterized by a configuration as a DC-AC converter or DC-DC converter or AC-DC converter or AC-AC converter.

10. Converter (10) according to claim 1, characterized by a regulating unit (1) formed on the side of the signal generator, adapted to regulate the input current, wherein the regulating unit preferably comprises an input voltage control and/or a pulse-width modulation (PWM) unit and/or a burst modulation control.

11. Converter (10) according to claim 1, characterized by a regulating unit (2) formed on the side of the consumer, adapted to regulate the output voltage and/or adapted to maintain a constant equivalent resistance at a node (40) of the converter (10).

12. Converter (10) according to claim 1, characterized by a rejection circuit (25) formed on the side of the signal generator upstream of a first resonant unit (15).

13. Power device comprising at least one converter (10) according to claim 1, wherein the converter (10) is formed between a signal generator circuit and a consumer circuit.

14. Power device according to claim 13, characterized in that the consumer circuit comprises a rectifier circuit followed by an optional load regulation (2) and an optional DC current load.

15. Power device according to claim 13, characterized by a regulating unit (1) for regulating the input signal, which is an input voltage control and/or a pulse-width modulation (PWM) unit and/or a burst modulation control.

Description

[0073] The invention will be explained in greater detail below using examples of embodiment and with the aid of figures.

[0074] In the figures:

[0075] FIG. 3a shows a two-step up converter;

[0076] FIG. 3b shows a two-step down converter;

[0077] FIG. 4a shows a two-step down converter;

[0078] FIG. 4b shows a two-step up converter;

[0079] FIG. 5 shows a two-step up converter according to a further embodiment of the invention;

[0080] FIG. 6 shows a complete two-step up system;

[0081] FIG. 7 shows a complete two-step down system; and

[0082] FIG. 8 shows a two-step up converter with a diode multiplier.

[0083] FIGS. 1a-2b show, as already mentioned, four possibilities for obtaining a full resonant up conversion or a full resonant down conversion. These represented converters are based on basic resonator structures, wherein in the electric representations the represented coil L stands as a placeholder for the processing of kinetic energy, condenser C stands as a placeholder for the processing of potential energy. Moreover, resistors R and r are represented. Resistor r is connected to inductive element L and symbolises kinetic power losses. Potential losses are usually negligible. Resistor R, on the other hand, symbolises extracted energy.

[0084] FIG. 1a and FIG. 1b represent the two possible cases for up converters. FIG. 2a and FIG. 2b represent the two possible cases for down converters.

[0085] FIG. 3a and FIG. 3b represent circuits or situations in which all the intermediate impedance values are resistive. These circuits or situations are associated with the lowest dissipation levels, since energy is not allowed to oscillate in-between successive stages. The situations represented in FIG. 3a and FIG. 3b can occur only for specific values of the inductive reactance units and capacitor units.

[0086] FIG. 3a represents a two-step up converter 10, wherein a converter according to the embodiment of FIG. 1b follows a converter according to the embodiment of FIG. 1a.

[0087] A two-step down converter 10 is represented in FIG. 3b, wherein a converter according to the embodiment of FIG. 2b follows a converter according to the embodiment of FIG. 2a.

[0088] It is also possible for identically formed converters to be constituted following one another. The intermediate impedance values are resistive with the best tuning conditions. It applies approximately: L.sub.1C.sub.1.sup.2=L.sub.2C.sub.2.sup.2. It is possible for slight deviations of this basic tuning to occur on account of losses, especially in connection with piezoresonators used. Piezoresonators have very sharp response behaviour around resonance.

[0089] FIGS. 3a and 3b show in each case the intermediate resistance property for the best performance by the represented box reduction process R.fwdarw.R.fwdarw.R.

[0090] FIGS. 4a and 4b represent two-step converter 10, wherein the inductive reactance units comprise identical components. Converters 10 each comprise two resonant units 15, 16, which are formed from several inductive reactance units L.sub.0 and in each case from a capacitor unit C.sub.0.

[0091] The voltage amplification is approx. 3 (in FIGS. 4a) and (in FIG. 4b) for each individual step, wherein the total amplification amounts to approx. 9 (in FIG. 4a) and 1/9 (in FIG. 4b). All the impedances vary from one stage to the next at a value which corresponds to the square of the voltage ratio. FIGS. 4a and 4b represent piezoelectric elements instead of coils. This emphasises the fact that the inductive reactance units can be formed from all the elements available to the technology.

[0092] FIG. 5 shows a similar two-step up converter 10, as is represented in FIG. 4b. Converter 10 represented in FIG. 5, however, has a higher power capability, since the number of elements, i.e. the piezoelectric resonators, is doubled. Compared to the embodiment represented in FIG. 4b, the piezoelectric elements are doubled in each case and placed in parallel with the original piezoelectric elements.

[0093] A voltage ratio of 4, 9, 16, 25 can be achieved for the basic series/parallel matching of two, three, four, five elements. In such series parallel arrangements as represented in FIG. 5, the total reactive power level for the two stages 15, 16 is the same, if the reactance control requirements are met. Since the total power is equally spread in the inductive reactance units, the power level is also the same for all inductive reactance units.

[0094] For most embodiments of inductive reactance units, it is the case that an optimum value C.sub.0 for the serial equivalent capacitance must be defined in connection with inductance value L.sub.0, in order to achieve the best quality factor for the inductive reactance unit. The optimum C.sub.0 value depends on one hand on the technology used and on the other hand on the selected resonance frequency and the reactive power level.

[0095] In the example represented in FIG. 5, the capacitance values can be obtained by similar series/parallel arrangements of reference value C.sub.0. If the various groups of inductive reactance units do not have similar Q-factors or if the losses or temperature rise are larger in some places, it is possible to use a different number of components in successive steps 15, 16.

[0096] FIG. 6 represents an example of a complete two-step up converter 10. Box 1 symbolises regulating units, control devices and protection devices. A typical half-bridge switching device follows, which is formed with the aid of two MOSFET. The square wave signal then passes to a first resonant unit 15 and a second resonant unit 16. A half-bridge diode arrangement 20 is used to rectify the higher voltage. Box 2 follows, which for example symbolises a voltage regulation circuit. In order to achieve a high degree of efficiency, the regulating units (box 1 and box 2) should work in order that the equivalent resistance at node 40 depends slightly on the load consumption.

[0097] FIG. 7 represents a similarly formed two-step down converter 10. A rejection circuit 25 is formed between first resonant unit 15 and a signal generator which generates square wave signals. The aim of this circuit 25 is to suppress/reject harmonics. This rejection circuit 25 can be produced from a smaller number of components used in connection with resonant units 15 and 16. The selection regarding the number of components in connection with rejection circuit 25 depends on how efficiently harmonics have to be suppressed.

[0098] FIG. 8 represents a further converter 10, i.e. a two-step up converter 10. The latter comprises only one resonant unit 15, wherein a voltage multiplier 30 is formed in respect of the second stage. First resonant unit 15 comprises piezoelectric resonators arranged in series, wherein the second stage or voltage multiplier 30 is an 6 voltage multiplier (series-series type).

LIST OF REFERENCE NUMBERS

[0099] 10 converter

[0100] 15 resonant unit

[0101] 16 resonant unit

[0102] 20 semiconductor diode arrangement

[0103] 25 rejection circuit

[0104] 30 voltage multiplier

[0105] 40 node