CN102916680B - A kind of multiplication of voltage square-wave generator of the repetition rate based on magnetic switch - Google Patents

Abstract

The invention discloses a voltage doubler square wave generator based on the repetition frequency of a magnetic switch, comprising an adjustable pulse source, a magnetic pulse compression circuit, a square wave voltage doubler Marx generator and a matching load; the square wave generator is cascaded in After the main capacitor or pulse transformer, charge the pulses of all levels in parallel, and then discharge them in series to match the load to obtain the output square wave pulse, so as to achieve the purpose of voltage doubling, high repetition frequency, and compressed rising edge. The pulse forming switch of the present invention is a magnetic switch, which replaces the traditional gas switch. In view of the fact that the magnetic switch does not have the problems of electrode ablation and insulation recovery, the circuit can operate at a high repetition rate. In the examples described later, the square wave source It can achieve a repetitive working frequency of more than 20kHz, which is much higher than the traditional 100Hz repetitive working frequency based on pulse-forming line square wave sources. The use of magnetic switches also has the effect of steepening the rising edge of the square wave.

Description

A Repetitive Frequency Square Wave Generator Based on Magnetic Switch

technical field

The invention belongs to the technical field of pulse square wave generators, and relates to a voltage doubler square wave generator based on the repetition frequency of a magnetic switch.

Background technique

Due to the urgent application needs of civil industry, environmental protection, medical research and national defense and military fields, the square wave pulse power source has ushered in a peak period of development, which puts forward stricter requirements on power level, rise time, and especially repetitive working frequency. The traditional square wave source using the pulse forming line as the pulse forming element is difficult to obtain a high repetition rate, and can achieve a repetition rate of the order of 100H at most.

Document 1 (Harjes H, Reed K, Buttram M, et al. The Repetitive High Energy Pulsed PowerModule[C], 19th International Power Modulator Symposium, 1990.) proposed a pulse square wave source based on pulse forming lines. The RHEPP (Repetitive High Energy Pulsed Power) device developed by Sandia National Laboratory in the United States uses a 5-stage magnetic pulse compressor to obtain a voltage pulse to charge the pulse forming line. After the voltage is superimposed, a pulse with a peak voltage of 2.5MV and a width of 60ns is generated. The pulse energy is 3kJ. Its repetition rate can reach 120Hz.

Document 2 (Yang Shi, Meng Zhipeng, Zhong Huihuang, Yang Hanwu, Qian Baoliang. Ultra-low impedance, all-solid-state wound ribbon pulse forming line. Applied Physics, 2010, 1(2):195-200.) for China Dr. Yang Shi of the Graduate School of National University of Defense Technology designed a long pulse and ultra-low impedance pulse generator based on magnetic switches and striplines. It passes through a solid-state strip with a characteristic impedance of 0.5Ω and an electrical length of 115ns. The DMD film is used as an insulating medium. The quasi-square wave pulse with a voltage of 17.8kV, a pulse width (FWHM) of 270ns, and a rising edge of about 20ns is obtained on the matched load by the shape pulse forming line. The system can run stably at a repetition frequency of 10Hz.

The above-mentioned square wave pulse generating device with PFL (pulse forming line) as the key component, the pulse forming switch is mostly a gas switch, and the repetitive working frequency can reach the order of 100Hz at most, which is difficult to meet the current industrial development needs.

Contents of the invention

The invention provides a double voltage square wave generator based on the repetition frequency of a magnetic switch. The generator can operate at a high repetition frequency and output voltage double and high repetition frequency square wave pulses.

The present invention is realized through the following technical solutions:

A voltage doubler square wave generator based on the repetition frequency of a magnetic switch, including an adjustable pulse source, a magnetic pulse compression circuit, a square wave voltage doubler Marx generator and a matching load; after the magnetic pulse compression circuit is charged by an adjustable pulse source, The square wave voltage doubler Marx generator is charged in parallel, and the square wave voltage doubler Marx generator is charged in series and discharged to a matching load to obtain an output square wave pulse;

The magnetic pulse compression circuit includes a capacitor C connected in parallel with the adjustable pulse source and a magnetic switch MS connected in series with the square wave voltage doubler Marx generator. When the capacitor C is charged to the peak u ₀ by the adjustable pulse source, the magnetic switch MS is saturated and turned on. The capacitor C charges the square wave voltage doubler Marx generator through the saturated inductance of the magnetic switch MS;

The square wave voltage doubler Marx generator includes N-level charging and discharging units. Each charging and discharging unit includes a PFL, a pair of coupled inductance pairs and a magnetic switch MS. Connected to the PFL, the magnetic switch MS connects the shielding layer and the core of the adjacent PFL, and the coupled inductor pair is connected to the same end or different end of each PFL; when charging, the coupled inductor pair charges the N-level PFL in parallel, charging to After the peak value, the magnetic switches MS of each stage are saturated and turned on, and the N-stage PFLs are discharged in series to the matching load.

The magnetic pulse compression circuit charges N-level PFLs in parallel through coupled inductors. The equivalent impedance Z ₀ , length l, and wave propagation speed v parameters of each level of PFL are consistent. After the PFL is charged to the peak value, the magnetic switches MS of each level are simultaneously Saturated conduction, N-level PFLs in series discharge the matching load; through the wave process, each level of PFL generates on the matching load Double charging voltage, The square wave pulse of the pulse width is superimposed at all levels to obtain Double charging voltage, The pulse width is the repetition rate of the high voltage square wave pulse.

The described square wave voltage doubler Marx generator is to form a linear Marx generator, including N-level charging and discharging units, N-level PFLs are charged in parallel, and the shielding layer and core port of the same end of the PFL of each level are connected into the circuit through a pair of coupling inductors , and the coupled inductor pair is connected to the PFL in the form of the same terminal; the relevant parameters of the PFL and the coupled inductor pair at each level are the same, and the coupled inductors on each side of the N-level PFL loop have the same direction;

The PFLs of all levels are discharged in series through the magnetic switch MS. The charging current inflow terminal of the n+1th PFL is connected to the charging current outflow terminal of the n-level PFL through the magnetic switch MS. The magnetic switches MS of each level have the same parameters and are coupled to the same magnetic core; the sheath of the Nth-stage PFL is connected to a matching load.

A diode that flows in the same direction as the charging current is connected in parallel to the charging current outflow end of the magnetic switch MS of the adjacent charging and discharging unit.

A diode is connected in parallel between the charging current outflow end of the last-stage magnetic switch MS and the first-stage magnetic switch MS.

The square wave voltage doubler Marx generator is an isolated Marx generator for forming a line charging and discharging port, including N-level charging and discharging units, N-level PFLs connected in parallel for charging, and the shielding layer and core port at the head end of each level of PFL pass through a pair of coupling inductors Connected into the circuit, and the coupled inductor pair is connected to the PFL in the form of the same name end, the relevant parameters of the PFL and the coupled inductor pair at each level are the same, and the direction of the same name end of the coupled inductor on each side of the N-level PFL circuit is consistent;

The PFLs of all levels are discharged in series through the magnetic switch MS. The tail end wire core of the n+1th PFL is connected to the tail end wire skin of the n-level PFL through the magnetic switch MS, and the wire core of the first-stage PFL is connected to the ground through the magnetic switch MS. , the magnetic switches MS of each stage have the same parameters and are coupled to the same magnetic core; the wire sheath of the Nth stage PFL is connected to a matching load.

The adjustable pulse source is a pulse source with adjustable frequency and pulse width.

The magnetic switch MS is composed of a plurality of magnetic cores stacked and wound with wires, and the parameters of the magnetic switch are adjusted by changing the number of winding turns and the number of magnetic switches: volt-second product α, that is, the magnetic core is saturated from negative to The increase value of the flux linkage during the positive saturation process, thereby controlling the saturation time of the magnetic switch at a certain voltage. Since the equivalent inductance value of the magnetic switch changes suddenly before and after saturation, the two terminals of the magnetic switch can be regarded as disconnected before saturation, and as connected after saturation, resulting in a similar working characteristic of the switch, so that after the saturation of the magnetic switch, each Stage PFL discharges in series.

The load connected to the PFL-based square wave pulse generator is a matching load NZ ₀ , where N is the number of stages, and Z ₀ is the characteristic impedance of the PFL.

Compared with the prior art, the present invention has the following beneficial technical effects:

The voltage doubler square wave generator based on the repetition frequency of the magnetic switch provided by the present invention uses the coupling inductance to charge and isolate, the magnetic switch is a pulse forming switch, and the pulse forming line is the square wave voltage doubler Marx of the high repetition frequency of the square wave generating element. generator. N-level PFLs are charged in parallel through coupled inductors, and the Z ₀ , l, and v parameters of each level of PFL are required to be consistent, and the magnetic switches of each level are saturated and turned on at the same time after charging to the peak value;

N-level PFLs are connected in series to discharge the matching load NZ0, and each level of PFL is generated on the matching load through the wave process Double charging voltage, pulse width of the square wave pulse, the stages are superimposed to obtain Double charging voltage, The pulse width is the repetition rate of the high voltage square wave pulse.

The voltage doubler square wave generator based on the repetition frequency of the magnetic switch provided by the present invention, the pulse forming switch is a magnetic switch (saturable inductance), which replaces the traditional gas switch. In view of the fact that the magnetic switch does not have the problems of electrode ablation and insulation recovery, As a result, the circuit can operate at a high repetition frequency. In the example described later, the square wave source can achieve a repetition frequency above 20 kHz, which is much higher than the 100 Hz level repetition frequency of the traditional square wave source based on pulse forming lines. The use of magnetic switches also has the effect of steepening the rising edge of the square wave.

The voltage doubler square wave generator based on the repetition frequency of the magnetic switch provided by the present invention adopts the structure of the coupled inductance isolation type Marx generator, which ensures fast charging and reduces the requirement for the volt-second product of the saturable inductance.

The voltage doubling square wave generator based on the repetition frequency of the magnetic switch provided by the present invention realizes the voltage doubling square wave pulse generation function. As long as the input power is the repetition frequency, the voltage doubler square wave generator can work in the repetition frequency state.

Description of drawings

Figure 1 is a circuit structure diagram of a voltage doubler square wave generator (secondary) based on the repetition frequency of a magnetic switch.

Fig. 2 is a circuit topology diagram of a typical linear Marx generator based on a two-stage magnetic switch.

Fig. 3 is the experimental voltage waveform diagram of the voltage doubler square wave generator (secondary) based on the repetition frequency of the magnetic switch.

Fig. 4 is a simulation voltage waveform diagram of a voltage doubler square wave generator (secondary) based on the repetition frequency of the magnetic switch.

Fig. 5 is a circuit topology diagram of a two-stage isolated Marx generator based on a magnetic switch to form a line charging and discharging port.

Fig. 6 is a circuit topology diagram of a two-stage linear Marx generator based on magnetic switch parallel charging.

Figures 7-1 to 7-2 are the topological diagrams of the two-stage linear Marx generator based on magnetic switch parallel charging diode current limiting.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

The invention provides a double voltage square wave generator based on the repetition frequency of a magnetic switch. The square wave generator is cascaded after the main capacitor or pulse transformer, and after charging the pulse forming lines of all levels in parallel, it is discharged in series to the matching load to obtain Output square wave pulses to achieve the purpose of voltage doubling, high repetition rate, and compression of rising edges.

A voltage doubler square wave generator based on the repetition frequency of a magnetic switch, including an adjustable pulse source, a magnetic pulse compression circuit, a square wave voltage doubler Marx generator and a matching load; after the magnetic pulse compression circuit is charged by an adjustable pulse source, The square wave voltage doubler Marx generator is charged in parallel. After the square wave voltage doubler Marx generator is charged, it is discharged in series to the matching load to obtain an output square wave pulse;

The magnetic pulse compression circuit includes a capacitor C connected in parallel with the adjustable pulse source and a magnetic switch MS connected in series with the square wave voltage doubler Marx generator. When the capacitor C is charged to the peak u ₀ by the adjustable pulse source, the magnetic switch MS is saturated and turned on. The capacitor C charges the square wave voltage doubler Marx generator through the saturated inductance of the magnetic switch MS;

The square wave voltage doubler Marx generator includes N-level charging and discharging units. Each charging and discharging unit includes a PFL (pulse forming line), a pair of coupled inductance pairs and a magnetic switch MS. The PFL is connected to the circuit through the coupled inductance pair and the coupled inductance The pair is connected to the PFL in the form of the end of the same name, the magnetic switch MS is connected to the shielding layer and the core of the adjacent PFL, and the coupled inductor is connected to the same or different end of each PFL; when charging, the coupled inductor pairs N-level PFL Charging in parallel, after charging to the peak value, the magnetic switches MS of each stage are saturated and turned on, and the N-stage PFLs are discharged in series to match the load.

The magnetic switch MS is composed of multiple magnetic cores stacked and wound with wires. The parameters of the magnetic switch are adjusted by changing the number of winding turns and the number of magnetic switches: volt-second product α, that is, the magnetic core is saturated from negative to positive. The increase value of the flux linkage in the process, thereby controlling the saturation time of the magnetic switch under a certain voltage. Since the equivalent inductance value of the magnetic switch changes suddenly before and after saturation, the two terminals of the magnetic switch can be regarded as disconnected before saturation, and as connected after saturation, resulting in a similar working characteristic of the switch, so that after the saturation of the magnetic switch, each Stage PFL discharges in series.

The load connected to the PFL-based square wave pulse generator is a matching load NZ ₀ , where N is the number of stages, and Z ₀ is the characteristic impedance of the PFL.

The voltage doubler square wave generated by the voltage doubler square wave generator based on the repetition frequency of the magnetic switch is as follows:

N-level PFLs are charged in parallel through coupled inductors. The equivalent impedance Z ₀ , length l, and wave propagation speed v parameters of each level of PFL are required to be consistent. Discharge to the matching load NZ ₀ , through the wave process each stage of PFL is generated on the matching load Double charging voltage, pulse width of the square wave pulse, the stages are superimposed to obtain Double charging voltage, The pulse width is the repetition rate of the high voltage square wave pulse.

Specifically, the coupled inductor is used for charging and isolation, the magnetic switch is a pulse forming switch, and the pulse forming line is a square wave voltage doubler Marx generator with a high repetition frequency of a square wave generating element. Due to the differences in coupling inductors, magnetic switches, and wire connection methods, the Marx generator has a variety of topological structures, and some typical circuit topological structures are listed below.

Example 1

See Figure 1 and Figure 2, a typical linear Marx generator based on a magnetic switch, including a pulse source with adjustable frequency pulse width; a magnetic pulse compression circuit; a linear Marx generator based on a magnetic switch; four parts of a matching load, The structure of the linear Marx generator is:

N-level PFLs are charged in parallel, and the shielding layer (skin) and core port at one end of each level of PFL are connected to the circuit through a pair of coupled inductors, and the pair of coupled inductors is connected to the PFL with the same name, N-level PFL and its coupled inductor The relevant parameters of the pair should be exactly the same, and the direction of the same-named end of the coupled inductor on each side of the N-level PFL circuit should be consistent. The connection method of all levels of PFLs discharged in series through magnetic switches is as follows: the charging current inflow terminal of the n+1th PFL is connected to the charging current outflow terminal of the n-level PFL through a saturable inductance (magnetic switch), and the saturable inductance of each level has Same parameters and coupled to the same core. The sheath of the Nth stage PFL is connected to a matched load.

When _C1 is charged to the peak _u0 by the preceding circuit, the magnetic switch MS1 is saturated and turned _on , and then _C1 starts to resonantly charge the Marx generator through the saturated inductance _of MS1. During this charging phase, the current sum of the coupled inductors of the Marx generator is zero, thus guaranteeing that it can be considered as a short circuit. Therefore, the Marx generator is equivalent to two PFLs connected in parallel to obtain good charging consistency.

When PFL ₁ and PFL ₂ are resonantly charged in parallel to the peak value u ₀ , the magnetic switches MS ₂ and MS ₃ are saturated and turned on, and PFL ₁ and PFL ₂ are quickly discharged in series to the matching load Z _L (Z _L is equal to 2Z ₀ ), at this time the coupling Inductors act as stage-to-stage isolation. Each stage of PFL forms an amplitude on the matching load through the wave process Double charging voltage u ₀ 、 Square wave pulse with pulse width, two-stage superposition to obtain amplitude u ₀ , Pulse width repetition frequency high-voltage square wave pulse, so as to achieve the goal of voltage doubling, high repetition frequency, and square wave pulse output.

The pulse forming lines PFL ₁ -PFL ₂ selected in the experiment are SYV series radio frequency coaxial cables, the model is 5-3-1, the wave impedance is 75Ω, the length is 95 meters, and the pulse source with adjustable frequency and pulse width generates a pulse with an amplitude of 300V. Pulse output with a width of 4μs, matched to a 150Ω resistor.

Figure 3 shows the experimental waveforms. It can be seen that the charging consistency of PFL ₁ -PFL ₂ remains good. When PFL ₁ -PFL ₂ is charged to a peak value of 320V, the magnetic switches MS ₂ -MS ₃ are saturated and turned on, and the PFLs are discharged in series to form a matching load. The square wave generates a square wave waveform of 380V, a pulse width at half maximum of 800ns, and a rising edge of 330ns, achieving good voltage doubling.

Figure 4 is the waveform obtained by Pspice software simulation. The PFL is charged to a peak value of 440V, the magnetic switch is saturated and turned on, and a square wave with an amplitude of 480V, a rising edge of about 170ns, and a pulse width of about 950ns is generated on the matching load, which verifies the good voltage doubling and its Square wave generation characteristics.

Example 2

Figure 5 shows the circuit topology diagram of the isolated Marx generator with two-stage forming line charge and discharge ports. Compared with the circuit topology of the two-stage Marx generator based on magnetic switches, the connection method of the magnetic switch is changed: PFL ₅ The first end of PFL ₆ is connected to the circuit through a coupling inductor, and the tail end is connected in series with a magnetic switch to discharge to a matching load.

The connection method of the magnetic switch at the end is as follows: the wire core at the end of the first-stage PFL is grounded through MS7, and the end wire sheath of the n-stage PFL is connected to the end wire core of the n+1-stage PFL through a magnetic switch. The small inductance of the coupling inductance during the charging process is equivalent to a short circuit, the large inductance of the magnetic switch is equivalent to an open circuit, and the Marx generator is equivalent to a parallel connection of PFLs to obtain good charging consistency.

The advantage of the two-stage formed line charging and discharging port isolation type Marx generator is that the voltage fluctuation at the head end of the PFL at the moment of series discharge takes a transmission time The wave process is transmitted to the end of the discharge, which can improve the rising edge of the output square wave on the matched load, so as to obtain a higher quality square wave pulse.

Example 3

Figure 6 shows the circuit topology of the two-stage magnetic switch parallel charging type Marx generator. Compared with the circuit topology of the two-stage magnetic switch-based linear Marx generator, the positions of the magnetic switch and the PFL are reversed. The magnetic switches MS ₁₀ -MS ₁₂ are charged in parallel through coupled inductance.

The advantage of the two-stage magnetic switch parallel charging type Marx generator is that in the original circuit topology, when the impedance of the magnetic switch MS ₁₀ -MS ₁₂ is compared with the impedance of PFL ₉ -PFL ₁₀ , MS ₁₀ -MS ₁₂ will flow through during the charging process. Larger currents cause different currents flowing through each coupled inductor, resulting in unbalanced magnetic flux and poor charging consistency of PFL ₉ -PFL ₁₀ . The topology shown in Figure 6 will improve the magnetic flux balance of the coupled inductor when a large current flows through the magnetic switch, thereby steepening the rising edge of the output square wave.

As shown in Figure 6, the current-limiting type Marx generator with two magnetic switches connected in parallel and charging diodes will have a pre-charge phenomenon on the matching load when it is discharged in series, and the characteristics of reverse flow can be limited by the diodes to improve the waveform, thus forming a circuit as shown in the attached figure 7-1. The two-stage magnetic switch shown in Figure 7-2 is connected in parallel with charging diodes to form a linear Marx generator, and the diode will reduce the pre-pulse to obtain higher-quality square wave pulses.

Claims (5)

1. based on a multiplication of voltage square-wave generator for the repetition rate of magnetic switch, it is characterized in that, comprise adjustable pulse source, magnetic pulse compression circuit, square wave multiplication of voltage Marx generator and matched load; Magnetic pulse compression circuit is after the charging of adjustable pulse source, and to square wave multiplication of voltage Marx generator charged in parallel, after the charging complete of square wave multiplication of voltage Marx generator, discharged in series obtains to matched load and exports square-wave pulse;

Magnetic pulse compression circuit comprises and the electric capacity C of adjustable pulse source parallel connection and the magnetic switch MS that connects with square wave multiplication of voltage Marx generator, and electric capacity C is charged to peak value u by adjustable pulse source ₀time, magnetic switch MS saturation conduction, electric capacity C is charged to square wave multiplication of voltage Marx generator by the pulsactor of magnetic switch MS;

Square wave multiplication of voltage Marx generator comprises N level charge/discharge unit, every grade of charge/discharge unit comprise a PFL, a pair coupling inductance to a magnetic switch, PFL by coupling inductance to be connected into circuit and coupling inductance to being connected to PFL in Same Name of Ends mode, magnetic switch MS connects screen and the core of adjacent level PFL, with coupling inductance to the same end or the heterodoxy that are connected to every grade of PFL; When charging, coupling inductance carries out charged in parallel to N level PFL, magnetic switch MS saturation conduction at different levels after charging to peak value, and N level PFL discharged in series is to matched load;

Described square wave multiplication of voltage Marx generator is for forming line discharge and recharge port isolated form Marx generator, comprise N level charge/discharge unit, N level PFL charged in parallel, screen, the core port of every grade of PFL head end are connected into circuit by a pair coupling inductance, and this coupling inductance is connected to PFL in Same Name of Ends mode, the PFL of every grade and the right relevant parameter of coupling inductance identical, the coupling inductance Same Name of Ends direction of every side, N level PFL loop is consistent;

PFL at different levels is by magnetic switch discharged in series, the tail end core of N+1 level PFL passes through the skin-deep company of tail wire of magnetic switch MS and N level PFL, the core of the PFL of the first order is connected to ground by magnetic switch MS, and magnetic switch MS at different levels has identical parameters and is coupled in same magnetic core; The line skin of N level PFL is connected to matched load.

2., as claimed in claim 1 based on the multiplication of voltage square-wave generator of the repetition rate of magnetic switch, it is characterized in that, magnetic pulse compression circuit carries out charged in parallel by coupling inductance to N level PFL, the equiva lent impedance Z of every grade of PFL ₀, length l, velocity of wave propagation vparameter is all consistent, and PFL is magnetic switch MS at different levels saturation conduction simultaneously after charging to peak value, and N level PFL series connection is discharged to matched load; Produced on matched load by the every one-level PFL of wave process times charging voltage, the square-wave pulse of pulsewidth, superposition at different levels obtains times charging voltage, the repeated frequency high-voltage square-wave pulse of pulsewidth.

3., as claimed in claim 1 based on the multiplication of voltage square-wave generator of the repetition rate of magnetic switch, it is characterized in that, described adjustable pulse source is the clock of frequency, adjustable pulse width.

4. as claimed in claim 1 based on the multiplication of voltage square-wave generator of the repetition rate of magnetic switch, it is characterized in that, magnetic switch MS adopts multiple magnetic core stacked and the mode being wound around wire is formed, by changing the parameter of number of turns and magnetic switch number adjustment magnetic switch: voltagesecond product α, namely magnetic core is saturated to the added value of magnetic flux forward saturation history from negative sense, thus controls the saturation time of magnetic switch under certain voltage.

5., as claimed in claim 1 based on the multiplication of voltage square-wave generator of the repetition rate of magnetic switch, it is characterized in that, the load that square-wave pulse generator connects based on PFL is matched load NZ ₀, N is progression, Z ₀for the characteristic impedance of PFL.