Multi-signal-source cascade high-efficiency power synthesis circuit based on transformer coupling

Abstract

The utility model belongs to the technical field of electric power engineering, and relates to a multi-signal source cascade high-efficiency power synthesis circuit based on transformer coupling, which comprises a signal generator and a plurality of broadband power amplification branches connected in parallel, each broadband power amplification branch has the same structure and comprises a signal amplifier, a coupling transformer and an impedance tuning circuit which are connected in sequence; the impedance tuning circuit adopts an L-C circuit; the output ends of the impedance tuning circuits of the broadband power amplification branches are connected in sequence, and the output ends of the impedance tuning circuits of the first broadband power amplification branch and the last broadband power amplification branch serve as the output end of the multi-signal-source cascade efficient power synthesis circuit. According to the high-power signal source output circuit, efficient synthesis of multiple paths of signals can be achieved through multi-stage amplification, and the high-power signal source output circuit is safe, simple and efficient.

Description

TECHNICAL FIELD

[0001] The utility model belongs to electric power engineering technical field relates to a kind of multi-signal source cascade high-efficiency power synthesis circuit based on transformer coupling. BACKGROUND

[0002] At present, many cables have been in operation for more than 15 years, and are gradually entering an aging state. Cable failures occur frequently, affecting the reliability of power supply. Therefore, it is particularly important to accurately identify potential defects in cables in advance.

[0003] In recent years, the broadband impedance method has a good recognition rate for cable defects and is widely used in the positioning of cable defects and faults. However, the existing broadband impedance method test signal source usually uses a "decoder (DAC) + power amplifier" to provide. Limited by the power limit of the power amplifier, the output voltage of the existing broadband impedance method is low, and the power is small, which is difficult to stimulate weak defects in the cable, resulting in insufficient representation for defect detection under low voltage excitation.

[0004] Connecting multiple small-power signal sources through series-parallel circuits and other organic cascades to form a large-power signal source is an effective method to solve the above problems. However, due to the influence of signal source voltage resistance, line stray parameters and signal source nonlinear characteristics, directly connecting multiple signal sources in series and parallel has the following two problems: (1) connecting multiple signal sources in series to form high voltage may cause system insulation deficiency and burnout, so an isolation circuit is needed; (2) multiple signal sources are affected by line stray parameters and signal source nonlinear characteristics, which may cause inconsistent signal synthesis phase, uneven voltage in series, and uneven current in parallel, so an impedance phase adjustment circuit is needed.

[0005] Therefore, there is an urgent need to develop a safe, simple and efficient high-power signal source output circuit. UTILITY MODEL CONTENTS

[0006] The utility model aims at the above technical problems existing in the prior art, and provides a multi-signal source cascade high-efficiency power synthesis circuit based on transformer coupling, to efficiently synthesize multiple signal sources.

[0007] To achieve the above purpose, the utility model adopts the following technical solutions.

[0008] The utility model provides a kind of multi-signal source cascade high-efficiency power synthesis circuit based on transformer coupling, it includes signal generator and several parallel broadband power amplification branch;Each broadband power amplification branch structure is same, including signal amplifier, coupling transformer and impedance tuning circuit connected in turn;The impedance tuning circuit uses L-C circuit;The impedance tuning circuit output end of each broadband power amplification branch is connected in turn, and the impedance tuning circuit output end of first broadband power amplification branch and last broadband power amplification branch is as the output end of multi-signal source cascade high-efficiency power synthesis circuit.

[0009] In an implementation manner, the negative pole of the signal amplifier input end is connected between the first resistor and the second resistor in series, the other end of the first resistor is grounded, and the other end of the second resistor is connected to the output end of the signal amplifier; the positive pole of the signal amplifier input end is connected to the output end of the signal generator through the third resistor.

[0010] In an implementation manner, the signal amplifier is FPA301 or FPA302.

[0011] In an implementation manner, the turns ratio of the input end and the output end of the coupling transformer is 1:4.

[0012] In an implementation manner, the inductance and the capacitance in the L-C circuit are connected in parallel to the two output ends of the coupling transformer.

[0013] In an implementation manner, the frequency range of the circuit output signal is 100 Hz-10 MHz, the peak-to-peak value voltage of the output signal is greater than 1200 V, and the peak-to-peak value power of the output signal is greater than 20 W. The peak-to-peak value here refers to the difference between the maximum value and the minimum value of the signal in one period.

[0014] In an implementation manner, in order to meet the output signal power requirement, the number of broadband power amplification branches is at least 2.

[0015] In an implementation manner, in order to meet the output signal voltage requirement, the number of broadband power amplification branches is at least 11.

[0016] Compared with the prior art, the multi-signal source cascade high-efficiency power synthesis circuit based on transformer coupling provided by the utility model has the following beneficial effects:

[0017] (1) The utility model is provided with multiple broadband power amplification branches, each branch first realizes the amplification of electrical signals in sequence through a signal amplifier, then realizes the secondary amplification of electrical signals through a coupling transformer, and then adjusts the phase of the output voltage signal through an impedance tuning circuit, so that the sum of multiple output voltages is maximum, and the efficient synthesis of multiple signals is realized.

[0018] (2) The coupling transformer used in this utility model also has the function of coupling isolation;

[0019] (3) The present invention uses an impedance tuning circuit, which can also achieve impedance matching between the signal source side and the load. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the high-efficiency power combining circuit based on transformer coupling for multi-signal source cascade provided in Example 1. Detailed Implementation

[0021] The technical solutions of various embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] Example 1

[0023] like Figure 1 As shown, the high-efficiency power combining circuit based on transformer coupling of multiple signal sources provided in this embodiment includes a signal generator and several parallel broadband power amplifier branches.

[0024] The aforementioned signal generator is used to generate electrical signals. In this embodiment, the DG5000 series function / arbitrary waveform generator is used.

[0025] Each broadband power amplifier branch has the same structure, consisting of a signal amplifier, a coupling transformer, and an impedance tuning circuit connected in sequence. The output terminals of the impedance tuning circuits of each broadband power amplifier branch are connected sequentially, and the output terminals of the impedance tuning circuits of the first and last broadband power amplifier branches serve as the output terminals of a multi-signal source cascaded high-efficiency power combining circuit.

[0026] The signal amplifier used above is the FPA301. The electrical signal generated by the signal generator is amplified once by the signal amplifier. The FPA301 broadband power amplifier has a maximum output power of 10W and a maximum output amplitude of 28V. pp .like Figure 1 As shown, for the nth signal amplifier, the negative terminal of the signal amplifier input is connected to the first resistor R in series. n,1 Second resistor R n,2 Between, the first resistor R n,1 The other end is grounded, and the second resistor R n,2 The other end is connected to the output of the signal amplifier; the positive terminal of the signal amplifier's input is connected to the third resistor R. n,3connected with the output end of the signal generator. The first resistor R n,1 , the third resistor R n,3 are all 10kΩ, and the second resistor R n,2 is 20kΩ.

[0027] The coupling transformer is used for secondary voltage amplification of the electrical signal and has the function of coupling isolation. The transformer magnetic core of the coupling transformer adopts a nickel-zinc ferrite magnetic core FT240-3 with high magnetic permeability, has a bandwidth range of 1-30MHz, an initial magnetic permeability ≥850H and a magnetic saturation density of 350mT (25℃), and has excellent magnetic properties. The turns ratio (i.e. the number of turns of the input end and output end coils) of the primary winding before and after the coupling transformer is set to 1:4, which is the optimal turns ratio for signal transmission; the number of turns of the primary winding is 4, and the number of turns of the secondary winding is 16, which can realize the maximum output of the voltage signal amplitude and frequency.

[0028] The impedance tuning circuit is used for adjusting the phase of the output voltage signal and realizing impedance matching between the signal source side and the load. In the embodiment, the impedance tuning circuit adopts an L-C circuit. The inductor and the capacitor in the L-C circuit are connected in parallel to the two output ends of the coupling transformer; the inductor L is 2nH; and the capacitor C is an adjustable capacitor with a range of 10pF-1000pF. The output ends of adjacent L-C circuits of each wideband power amplification branch are connected, and the free output ends of the first wideband power amplification branch and the last wideband power amplification branch are respectively taken as two output ends V out+ and V out- of the multi-signal source cascaded high-efficiency power synthesis circuit, so as to form a multi-stage impedance tuning circuit network with the L-C circuit as the core; the adjustable capacitor C in each L-C compensation circuit is adjusted with the first output voltage vector as the reference, so as to ensure that the sum of the multi-output voltages is the maximum.

[0029] The output signal frequency range of the multi-signal source cascaded high-efficiency power synthesis circuit is 100Hz-10MHz, the output signal peak-to-peak voltage is greater than 1200V, and the output signal peak-to-peak power is greater than 20W. In order to meet the technical index of the output signal power, at least 2 wideband power amplification branches are required. In order to meet the technical index of the output signal voltage, at least 11 wideband power amplification branches are required.

[0030] Those skilled in the art will appreciate that the embodiments herein are intended to help the reader understand the principles of the utility model and should be understood as not limiting the protection scope of the utility model to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations according to the technical inspirations disclosed in the utility model without departing from the essence of the utility model, and these modifications and combinations are still within the protection scope of the utility model.

Claims

1. A transformer coupled multi-signal source cascaded high efficiency power combining circuit, characterized in that, The signal generator and a plurality of parallel broadband power amplification branches; each broadband power amplification branch has the same structure, including a signal amplifier, a coupling transformer and an impedance tuning circuit connected in sequence; the impedance tuning circuit adopts an L-C circuit; The output ends of the impedance tuning circuits of the broadband power amplification branches are connected in sequence, and the output ends of the impedance tuning circuits of the first broadband power amplification branch and the last broadband power amplification branch are used as the output ends of the multi-signal source cascaded high-efficiency power synthesis circuit.

2. The transformer coupling based multi-signal source cascaded high efficient power combining circuit of claim 1, wherein, The negative electrode of the input end of the signal amplifier is connected between the first resistor and the second resistor in series, the other end of the first resistor is grounded, and the other end of the second resistor is connected to the output end of the signal amplifier; the positive electrode of the input end of the signal amplifier is connected to the output end of the signal generator through the third resistor.

3. The transformer coupled multi-signal source cascaded high efficient power combining circuit according to claim 2, wherein, The signal amplifier is FPA301 or FPA302.

4. The transformer coupled multi-signal source cascaded high efficient power combining circuit according to claim 1, wherein, The turns ratio of the input end and the output end of the coupling transformer is 1:

4.

5. The transformer coupled multi-signal source cascaded high efficient power combining circuit according to claim 1, wherein, The inductor and the capacitor in the L-C circuit are connected in parallel to the two output ends of the coupling transformer.

6. The transformer-coupled multi-signal source cascaded high-efficiency power combining circuit according to any one of claims 1 to 5, wherein, The frequency range of the output signal of the circuit is 100Hz-10MHz, the peak-to-peak voltage of the output signal is greater than 1200V, and the peak-to-peak power of the output signal is greater than 20W.

7. The transformer-coupled multi-signal source cascaded high-efficiency power combining circuit of claim 6, wherein, In order to meet the output signal power demand, the number of broadband power amplification branches is at least 2.

8. The transformer coupled multi-signal source cascaded high efficient power combining circuit according to claim 6, wherein, In order to meet the output signal voltage demand, the number of broadband power amplification branches is at least 11.

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