Air gap regulation and control system, air gap regulation and control method and waveform generation system

Abstract

The invention relates to the technical field of power supplies, and discloses an air gap regulation and control system, an air gap regulation and control method and a waveform generation system. The air gap regulation and control system comprises a supporting device, wherein a first end of the supporting device is connected with a fixed magnetic core of a voltage amplifier; the telescopic mechanism is mounted at the second end of the supporting device and is connected with the adjustable magnetic core of the voltage amplifier; the controller is used for acquiring a direct-current voltage component to be input into the voltage amplifier according to the target output voltage of the target output waveform of the voltage amplifier; when the direct-current voltage component is larger than or equal to the first voltage threshold value and smaller than the second voltage threshold value, the motor is controlled to drive the telescopic mechanism to stretch out and draw back so as to regulate and control the air gap between the magnetic cores to a preset air gap value. According to the voltage amplifier, the magnetic core air gap in the voltage amplifier can be actively adjusted according to the requirement of the output voltage, so that the problem of magnetic core saturation of the voltage amplifier easily caused by a wide load change range and waveform change is at least partially solved, and then high-voltage multi-waveform output can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to an air gap control system, an air gap control method and a waveform generating system. Background Art

[0002] In recent years, high-voltage power supply technology has developed rapidly and has been widely used in biomedicine, machinery manufacturing, aerospace, plasma processing and other fields. In some scenarios, high-voltage power supplies are required to have the ability to output multiple waveforms. For example, in plasma applications, the characteristics of high-voltage power supplies have a decisive effect on the electron energy density, energy consumption, efficiency and type of active particles generated by gas discharge. Different waveforms have their own advantages in processing different components. Different high-voltage pulse output waveforms are required under different working conditions to achieve the best processing efficiency.

[0003] The high-voltage power supply output used at home and abroad is difficult to meet the requirements of high voltage level and multi-waveform output at the same time. Under the requirements of multi-waveform conversion and wide load range, the problem of transformer core saturation is particularly prominent. For example, the operating load is too high to cause the core to saturate, the short-term voltage and current impact under pulse discharge can easily cause the core to saturate, and the DC component of the output waveform is too large to cause the core to saturate in one direction, etc., and it is impossible to take into account both functional requirements and processing efficiency during design.

[0004] Magnetic saturation means that when the magnetic flux of the transformer reaches a certain value, the magnetic field strength in the magnetic core has reached a saturated state and can no longer increase. At this time, the magnetic circuit of the transformer will be saturated, causing the magnetic flux to no longer change linearly with the change of voltage, but to change nonlinearly. After the transformer core is saturated, the voltage drops sharply, the primary current continues to increase, but the secondary current remains unchanged, which can easily lead to adverse consequences such as a significant reduction in energy transfer efficiency, severe heating of the transformer, and damage to the switch tube.

[0005] Usually, an air gap is added to the core of the transformer to prevent the saturation of the core. However, if the air gap is too large, the core loss will increase, resulting in a decrease in transformer efficiency. Therefore, an appropriate air gap length can effectively improve the transformer's anti-saturation ability and improve system efficiency. For high-voltage power supplies with multi-waveform high-voltage outputs, it is difficult to unify the appropriate air gap length when designing the transformer due to the complex types of output waveforms. Summary of the invention

[0006] The object of the present invention is to provide an air gap control system, an air gap control method and a waveform generating system, which can actively adjust the core air gap in a voltage amplifier according to the output voltage requirements, thereby at least partially solving the core saturation problem of the voltage amplifier that is easily caused by a wide load variation range and waveform variation, and further realizing the output of high voltage and multiple waveforms.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an air gap control system, which includes: a supporting device, a first end of which is connected to a fixed magnetic core of a voltage amplifier; a telescopic mechanism, which is installed at a second end of the supporting device and is connected to an adjustable magnetic core of the voltage amplifier; a motor, which is used to drive the telescopic mechanism to be telescoped; and a controller, which is used to perform the following operations: S1, obtaining a DC voltage component to be input to the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier; S2, obtaining a preset air gap value according to the DC voltage component; and S3, when the DC voltage component is greater than or equal to a first voltage threshold and less than a second voltage threshold, controlling the motor to drive the telescopic mechanism to be telescoped, so as to control the air gap between the adjustable magnetic core and the fixed magnetic core to the preset air gap value.

[0008] Preferably, the controller is also used to perform the following operations after executing S3: S4, start the waveform generator and the voltage amplifier, and obtain the ratio of the primary current to the secondary current; and S5, according to the ratio, perform the following operations: when the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, turn off the waveform generator and the voltage amplifier, and judge whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, and determine whether to increase the air gap according to the judgment result; when the ratio is equal to the ratio threshold, keep the waveform generator and the voltage amplifier running; or when the ratio is less than the ratio threshold, stop the waveform generator and the voltage amplifier and feedback "other faults".

[0009] Preferably, the controller is further configured to execute S4-S5 when the DC voltage component is less than the first voltage threshold.

[0010] Preferably, determining whether to increase the air gap based on the judgment result includes: when the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increasing the air gap, and executing S4-S5 until the ratio is less than or equal to the ratio threshold; or when the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, judging the relationship between the ratio and the ratio threshold, and performing the following operations based on the judgment result: when the ratio is greater than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "voltage amplifier saturation"; when the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier in operation; or when the ratio is less than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "other faults".

[0011] Preferably, the first voltage threshold is the product of the critical saturation voltage of the voltage amplifier and a preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is 0; and the second voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is a maximum value.

[0012] Preferably, obtaining the DC voltage component to be input into the voltage amplifier includes: obtaining the voltage to be input into the voltage amplifier based on the target output voltage and the ratio of the number of coil turns on the secondary side of the voltage amplifier to the number of coil turns on the primary side; performing Fourier transform on the obtained voltage; and determining the DC component in the voltage after the Fourier transform as the DC voltage component, wherein the target output voltage is greater than a preset voltage.

[0013] Through the above technical scheme, the present invention creatively connects the fixed magnetic core of the voltage amplifier through the first end of the supporting device; connects the adjustable magnetic core of the voltage amplifier through the telescopic mechanism installed at the second end of the supporting device; and performs the following operations through the controller: S1, according to the target output voltage of the target output waveform of the voltage amplifier, obtains the DC voltage component to be input to the voltage amplifier; S2, according to the DC voltage component, obtains the preset air gap value; and S3, when the DC voltage component is greater than or equal to the first voltage threshold and less than the second voltage threshold, controls the motor to drive the telescopic mechanism to extend and retract, so as to adjust the air gap between the adjustable magnetic core and the fixed magnetic core to the preset air gap value. The present invention can actively adjust the magnetic core air gap in the voltage amplifier according to the output voltage requirements, thereby at least partially solving the problem of magnetic core saturation of the voltage amplifier that is easily generated by a wide load variation range and waveform variation, and thus can achieve high voltage multi-waveform output.

[0014] A second aspect of the present invention provides an air gap control method, which is applied to a voltage amplifier, wherein the voltage amplifier includes a fixed magnetic core and an adjustable magnetic core, wherein the fixed magnetic core is connected to a first end of a supporting device; a telescopic mechanism is installed at the second end of the supporting device, and the telescopic mechanism is connected to the adjustable magnetic core. The air gap control method includes: S1, obtaining a DC voltage component to be input into the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier; S2, obtaining a preset air gap value between the adjustable magnetic core and the fixed magnetic core according to the DC voltage component; and S3, when the DC voltage component is greater than or equal to a first voltage threshold and less than a second voltage threshold, controlling a motor to drive the telescopic mechanism to extend and retract, so as to control the air gap between the adjustable magnetic core and the fixed magnetic core to the preset air gap value.

[0015] Preferably, after executing S3, the air gap control method also includes: S4, starting the waveform generator and the voltage amplifier, and obtaining the ratio of the primary current to the secondary current; and S5, performing the following operations according to the ratio: when the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, turning off the waveform generator and the voltage amplifier, and judging whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than a maximum air gap value, and determining whether to increase the air gap according to the judgment result; when the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier running; or when the ratio is less than the ratio threshold, stopping the waveform generator and the voltage amplifier and feeding back "other faults".

[0016] Preferably, the air gap control method further comprises: executing S4-S5 when the DC voltage component is less than the first voltage threshold.

[0017] Preferably, determining whether to increase the air gap based on the judgment result includes: when the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increasing the air gap, and executing S4-S5 until the ratio is less than or equal to the ratio threshold; or when the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, judging the relationship between the ratio and the ratio threshold, and performing the following operations based on the judgment result: when the ratio is greater than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "voltage amplifier saturation"; when the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier in operation; or when the ratio is less than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "other faults".

[0018] Preferably, the first voltage threshold is the product of the critical saturation voltage of the voltage amplifier and a preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is 0; and the second voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is a maximum value.

[0019] Preferably, obtaining the DC voltage component to be input into the voltage amplifier includes: obtaining the voltage to be input into the voltage amplifier based on the target output voltage and the ratio of the number of coil turns on the secondary side of the voltage amplifier to the number of coil turns on the primary side; performing Fourier transform on the obtained voltage; and determining the DC component in the voltage after the Fourier transform as the DC voltage component, wherein the target output voltage is greater than a preset voltage.

[0020] For specific details and benefits of the air gap control method provided by the embodiment of the present invention, please refer to the above description of the air gap control system, which will not be repeated here.

[0021] A third aspect of the present invention provides a waveform generating system, which includes: a signal generator; a waveform generator; a voltage amplifier for outputting a target output waveform; and the air gap control system for regulating the air gap between the adjustable magnetic core and the fixed magnetic core in the voltage amplifier to a preset air gap value according to the target output voltage of the target output waveform.

[0022] A fourth aspect of the present invention provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the air gap control method.

[0023] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0025] Figure 1 is a structural diagram of an air gap control system provided by an embodiment of the present invention;

[0026] Figure 2 is a structural diagram of a waveform generating system provided by an embodiment of the present invention;

[0027] Figure 3 is a BH magnetization curve of a ferrite material provided in one embodiment of the present invention;

[0028] Figure 4 is a flow chart of an air gap control method provided by an embodiment of the present invention;

[0029] Figure 5 is a structural diagram of an air gap control system provided by an embodiment of the present invention; and

[0030] Figure 6 It is a structural diagram of an air gap control system provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0032] The waveform generating system comprises a signal generator 20, a waveform generator 30, a voltage amplifier 40 and a controller 10. Figure 2 shown.

[0033] Specifically, the signal generator 20 can generate multiple waveform analog signals or digital signals according to the control signal given by the controller 10, and then transmit these analog signals or digital signals to the waveform generator 30. The multiple waveforms include but are not limited to sine waves, triangle waves (sawtooth waves), sine waves, trapezoidal waves (square waves), pulse waves and other waveforms. The signal generator 20 is provided with an operating voltage by a low-voltage power supply 50. The output waveform signal is a periodic signal, which can be a finite periodic signal or an infinite periodic signal. This signal generator 20 can exist alone or be integrated in the controller 10 as a part of the controller 10.

[0034] The waveform generator 30 may be a power amplifier circuit composed of a power electronic switch, which can convert the analog signal or digital signal inputted by the signal generation link into the control signal of the power electronic switch. The waveform generator 30 may be provided with an input voltage by a low voltage power supply 50, and the input voltage may be converted into a target output waveform through a power amplifier circuit, wherein the input voltage includes but is not limited to 220V industrial frequency sinusoidal AC and 380V three-phase AC. The target output waveform is power amplified according to the signal parameters inputted by the signal generation link, and the specific amplification factor is set by the controller 10 and has an upper limit (power amplification refers to outputting an output signal of a higher voltage level according to the parameter setting of the signal generation link, which seems to convert the analog signal into a high voltage waveform, so it is called "power amplification"). According to the output requirements, the peak voltage of the waveform generation link can be designed to be 2kV, 5kV, 10kV, 20kV, etc.

[0035] The voltage amplifier 40 further boosts the voltage of the waveform generation link to reach the working voltage (or target output voltage). The voltage amplitude output by the entire system is jointly determined by the waveform generation link and the voltage amplification link.

[0036] The high-voltage waveform generating system in the prior art is similar to the above-mentioned waveform generating system, but it does not include a voltage amplifier, but a transformer. The existing high-voltage waveform generating system needs to solve the following problems: 1. Under the same load, waveform changes can easily cause system mismatch. For example, when the power supply output changes from AC to pulse drive, the energy is more concentrated and a large amount of energy needs to be released in a shorter time, which can easily cause the transformer to saturate. 2. When multiple waveforms are output, it is easy to cause the DC component to be too large and saturate the transformer, and there is a lack of a pre-protection system; 3. When the load variation range is large, it is difficult for a fixed air-gap transformer to match the output requirements. When the load is too heavy (the output current is large), the energy that the transformer needs to transmit will increase, which can easily cause the transformer to saturate.

[0037] The present invention at least considers solving the transformer saturation problem, and realizes multi-waveform high voltage output by using the air gap control method through the signal generation link, waveform generation link and voltage amplification link. The present invention adopts an "active adjustment" (judgment parameter U d The air gap of the magnetic core is regulated by utilizing the characteristic that the DC component easily causes the saturation of the voltage amplifier and combining it with "passive protection means" (current ratio detection is also set to prevent core saturation during operation).

[0038] Embodiment 1

[0039] Figure 1 FIG. 1 is a structural diagram of an air gap control system provided by an embodiment of the present invention. Figure 1 As shown, the air gap control system 100 may include: a supporting device 1, a first end of which is connected to a fixed magnetic core 2 of a voltage amplifier; a telescopic mechanism 4, which is installed at a second end of the supporting device 1 and is connected to an adjustable magnetic core 3 of the voltage amplifier; a motor (not shown) for driving the telescopic mechanism 4 to extend and retract; and a controller (not shown) for controlling the air gap between the adjustable magnetic core 3 and the fixed magnetic core 2 according to a target output voltage of a target output waveform of the voltage amplifier.

[0040] Among them, the supporting device 1 can be a supporting frame. The magnetic core of the voltage amplifier is divided into two parts: a fixed magnetic core 2 and an adjustable magnetic core 3. The fixed magnetic core 2 is connected to the supporting frame and is fixed in position during operation; the adjustable part is connected to the telescopic mechanism 5 and can be moved during operation, thereby realizing the adjustment of the air gap of the magnetic core of the voltage amplifier. The magnetic core material can be ferrite, amorphous alloy, nanocrystalline alloy, etc.; the winding form and number of turns of the winding of the voltage amplifier are determined according to the load design, and the material can be copper; the material of the supporting frame is aluminum or other non-magnetic materials such as non-metal; the motor is controlled by the controller, and can drive the telescopic mechanism 4 to telescope according to the control requirements, so that the adjustable magnetic core 3 connected thereto moves to control the length of the air gap of the magnetic core of the voltage amplifier, and the control accuracy can be no less than 0.1mm.

[0041] The number of turns of the primary coil of the voltage amplifier is N1, the number of turns of the secondary coil is N2, and the average length is l c , Core cross-sectional area A c Parameters such as these can be determined by workload and operating scenario design.

[0042] like Figure 2As shown, the controller 10 is used to control the entire system, and can receive information from each device / link and issue control instructions. The chip of the controller 10 can be, but not limited to, a single-chip microcomputer, a DSP, a PLC, etc. The controller 10 and each device (for example, a signal generator 20, a waveform generator 30, and a motor) can use, but not limited to, the following communication methods: 485, 232, CAN, and the signal line has the ability to shield high-frequency electromagnetic radiation. The controller 10 has the ability to feedback the system status and display the current status, which can be achieved by means of a host computer display screen, an indicator light, etc. The controller 10 may also have circuit protection capabilities.

[0043] Specifically, the controller adjusts the air gap through the following steps.

[0044] S1, obtaining a DC voltage component to be input to the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier.

[0045] For step S1, the step of obtaining the DC voltage component to be input into the voltage amplifier may include: obtaining the voltage to be input into the voltage amplifier based on the target output voltage and the ratio of the number of coil turns on the secondary side of the voltage amplifier to the number of coil turns on the primary side; performing Fourier transform on the obtained voltage; and determining the DC component in the voltage after the Fourier transform as the DC voltage component.

[0046] Wherein, the target output voltage is greater than a preset voltage (eg, 220V).

[0047] First, if the target output voltage of the target output waveform is U o , then the voltage to be input to the voltage amplifier (ie, the output voltage of the signal generator or waveform generator / pre-generated voltage) u = U o *N1 / N2.

[0048] Then, the voltage u can be transformed into:

[0049]

[0050] In the formula, a0, a k 、b k It is called the Fourier coefficient. This formula indicates that any periodic waveform can be formed by superimposing j+1 waveforms.

[0051] Finally, only the DC component coefficient a0 is used to make the DC voltage component U d =a0. At this time, the air gap length of the voltage amplifier in the voltage amplification link is 0.

[0052] S2: Acquire a preset air gap value between the adjustable magnetic core and the fixed magnetic core according to the DC voltage component.

[0053] Specifically, the preset air gap value g can be determined through the following process.

[0054] Since the net magnetomotive force F of the winding of the voltage amplifier can be expressed as N1I1-N2I2, and from the magnetic circuit law, it can be known that it is related to the magnetic resistance R of the magnetic core of the voltage amplifier, and Φ is the magnetic flux in the magnetic circuit.

[0055] N1I1-N2I2=ΦR (1)

[0056] When calculating the DC component, the secondary current can be approximately considered to be zero. Without considering magnetic leakage, we can get (the following calculation only considers the DC component):

[0057] N1I1=ΦR=H c l c (2)

[0058] Using the magnetic field strength H c Get the magnetic induction intensity B c :

[0059] B c =μ r μ0H c (3)

[0060] In the formula, μ r is the relative magnetic permeability; μ0 is the vacuum magnetic permeability (μ0 = 4π×10 -7 H / m).

[0061] When the voltage amplifier has no air gap:

[0062] The magnetic flux is Φ = B c A c =μ r μ0H c A c , Ac is the core cross-sectional area;

[0063] The magnetic resistance is

[0064] By using equations (2) and (3), we can get that when the voltage amplifier is in critical saturation, that is, B c =B sat , the external current I m :

[0065]

[0066] In the formula, B sat is the saturation magnetic induction intensity of the ferrite core.

[0067] Considering the primary side equivalent internal resistance (or primary side equivalent internal resistance) r1, the line equivalent resistance r2, and the critical saturation voltage U of the gapless voltage amplifier m =I m (r1+r2), that is

[0068]

[0069] When the voltage amplifier contains an air gap (still only considering the DC component):

[0070] The magnetic circuit is composed of different magnetic resistances such as the magnetic core and the air gap. The entire magnetomotive force can be expressed as

[0071] F=N1I1=φ1R1+φ2R2+φ3R3+… (7)

[0072] Under normal circumstances, the magnetic flux in each part of the magnetic circuit is generally the same, and equation (7) can be transformed into: The magnetic circuit can be composed of different magnetic resistances, and the entire magnetomotive force can be expressed as

[0073] N1I1=φ(R1+R2+R3+…) (8)

[0074] The magnetic reluctance is related to the relative magnetic permeability of the material, and the magnetic field strength applied to the ferromagnetic material is nonlinear. Figure 3 As shown in Figure 1, if there is an air gap in the core, a larger current is required to achieve core saturation, because the introduction of the air gap will increase the magnetic resistance. Combining formula (8), we can know that Figure 3 The voltage amplifier magnetomotive force is shown as

[0075] F=φ(R c +R g ) (9)

[0076] Where R c Represents the magnetic resistance of the core, R g Represents the magnetic resistance of the air gap.

[0077] For the magnetic core, its magnetic resistance is:

[0078]

[0079] For the air gap, its relative magnetic permeability μ r =1:

[0080]

[0081] Where g is the air gap length.

[0082] The equivalent reluctance of the core with air gap is:

[0083]

[0084] When the air gap length g is very small compared to the cross-sectional area, assuming that the cross-sectional area of ​​the core is the same as the cross-sectional area of ​​the air gap, equation (12) can be simplified to

[0085]

[0086] The magnetic resistance of the core with air gap is equivalent to the relative magnetic permeability μ eff and length l c The magnetic core is as follows:

[0087]

[0088] If the relative magnetic permeability μ r >>1At this time, the equivalent magnetic permeability is

[0089]

[0090] according to Figure 3 As shown in the figure, the magnetic core with air gap can be equivalent to a magnetization curve with different slopes, and the air gap length determines the equivalent magnetic permeability μ eff The size of the air gap can be adjusted to change the magnetic permeability μ eff , thereby changing the slope of the magnetization curve and increasing the critical saturation current. The DC current on the primary side of the voltage amplifier with an air gap is I g , combined with the derivation process of the gapless voltage amplifier, we can get:

[0091]

[0092] Since the DC voltage component U d =I g (r1+r2), according to formula (15) (16), the relationship between DC voltage and air gap length can be obtained:

[0093]

[0094] When the adjustable air gap is at its maximum length g max When the voltage amplifier is in the critical saturation state, that is, B c =B sat , the maximum external DC voltage is:

[0095]

[0096] Therefore, according to formula (17) and considering the adjustment coefficient γ, the preset air gap value g can be set to:

[0097]

[0098] The adjustment coefficient γ is less than 1 and is used to indicate the contribution of the DC component to the core saturation, which can be obtained by calculation, simulation or preliminary experiment.

[0099] Of course, the preset air gap value is not limited to the above formula (19). For those skilled in the art, a reasonable setting can be made based on formula (19).

[0100] S3, when the DC voltage component is greater than or equal to the first voltage threshold and less than the second voltage threshold, the air gap between the adjustable magnetic core and the fixed magnetic core is adjusted to the preset air gap value by controlling the motor to drive the telescopic mechanism to extend and retract.

[0101] The first voltage threshold is the critical saturation voltage (e.g., U m ) multiplied by a preset ratio; and the second voltage threshold is the critical saturation voltage of the voltage amplifier when the air gap between the adjustable magnetic core and the fixed magnetic core is the maximum value (e.g., U max ) multiplied by the preset ratio.

[0102] Specifically, U is obtained by calculation, simulation or preliminary experiment. m and U max , U m is the critical saturation DC voltage of the gapless voltage amplifier, U max When the air gap is maximum (g max ) is the critical saturation DC voltage of the voltage amplifier. m and U max The specific calculation method of can be performed according to formulas (6) and (18).

[0103] The preset ratio may be an adjustment coefficient γ. Of course, the preset ratio is not limited to the adjustment coefficient, and may also be other reasonable coefficients.

[0104] If the amplitude satisfies γU max >U d ≥γU m , it is considered that the DC component of the voltage in the waveform generating link of the waveform generator is too high. Working in this state is very likely to cause the voltage amplifier in the voltage amplification link to saturate. The motor in the voltage amplification link is controlled to work and the air gap of the voltage amplifier core is increased. For example, the air gap length can be adjusted to the preset air gap value shown in the above formula (19).

[0105] In one embodiment, the controller is also used to perform the following operations after executing S3: S4, start the waveform generator and the voltage amplifier, and obtain the ratio of the primary current to the secondary current; and S5, according to the ratio, perform the following operations: when the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, turn off the waveform generator and the voltage amplifier, and determine whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than a maximum air gap value, and determine whether to increase the air gap based on the determination result; when the ratio is equal to the ratio threshold, keep the waveform generator and the voltage amplifier running; or when the ratio is less than the ratio threshold, stop the waveform generator and the voltage amplifier and feedback "other faults".

[0106] Specifically, determining whether to increase the air gap based on the judgment result includes: when the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increasing the air gap and executing S4-S5 until the ratio is less than or equal to the ratio threshold; or when the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, judging the relationship between the ratio and the ratio threshold, and maintaining or stopping the operation of the waveform generator and the voltage amplifier based on the judgment result.

[0107] Wherein, maintaining or stopping the operation of the waveform generator and the voltage amplifier according to the judgment result includes: when the ratio is greater than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "voltage amplifier saturation"; when the ratio is equal to the ratio threshold, maintaining the operation of the waveform generator and the voltage amplifier; or when the ratio is less than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "other faults".

[0108] The threshold value of the ratio of the primary current to the secondary current may be the ratio m' of the primary current to the secondary current when the voltage amplifier is in a critical saturation state under the DC voltage component. m' can be obtained through preliminary experiments or experience. When the DC voltage component is 0, m' is the inverse of the transformer ratio (N2 / N1). The critical saturation state of the transformer corresponds to Figure 3 The inflection point of the curve corresponding to the ferrite in the middle, for example, setting μ r When μ0 changes by more than 80%, it is considered critical saturation.

[0109] Specifically, when the air gap is adjusted to the preset air gap value, the waveform generation link and the voltage amplification link can be started, and the system enters the working state; the primary and secondary currents i of the voltage amplifier are collected. y 、i f , and calculate m = iy / i f Then, compare m with m': (1) When it is detected that m is greater than m', it means that the current on the primary side increases while the current on the secondary side remains basically unchanged. It can be inferred that the voltage amplifier is in saturation at this time, and the controller turns off the waveform generation link and the voltage amplification link. Next, determine whether the air gap length is less than the maximum length, and execute a or b according to the judgment result. a. If the air gap length is less than g at this time max , then the motor operation of the control voltage amplification link increases the air gap length by Δg, that is, g = g + Δg, and Δg can be set to 1 / 2g max ~1 / 5g max , and restart the waveform generation link and the voltage amplification link, and execute the subsequent links (that is, equivalent to repeatedly executing S4-S5). b. If the air gap length reaches or exceeds the maximum air gap value: m is still greater than m', the controller controls the system to shut down and returns the "voltage amplifier saturation" information; when m=m', the system is judged to be in normal working state at this time, and here equal to can be approximately equal to. Due to the influence of measurement errors and other factors, less than 5% can be approximately regarded as equal, and the "normal working" information is returned; when m<m', the system is judged to be in other fault states at this time, the system shuts down, and returns the "other fault" information. (2) When it is detected that m=m', the system is judged to be in normal working state at this time, and here equal to can be approximately equal to. Due to the influence of measurement errors and other factors, less than 5% can be approximately regarded as equal, and the "normal working" information is returned. (3) When it is detected that m<m', the system is judged to be in other fault states at this time, the system shuts down, and returns the "other fault" information.

[0110] In one embodiment, the controller is further configured to execute S4-S5 when the DC voltage component is less than the first voltage threshold.

[0111] If U d <γU m It is considered that the voltage DC of the waveform generation link meets the requirements, the waveform generation link and the voltage amplification link are started, and the system enters the working state. The specific process of S4-S5 can be found in the above-mentioned related description content, which will not be repeated here.

[0112] In one embodiment, the controller is further configured to, when the DC voltage component is greater than the second voltage threshold, place the waveform generator and the voltage amplifier in a standby state and provide feedback indicating that "the target waveform does not meet the requirements".

[0113] If the amplitude U d ≥γU max, it is considered that the DC component of the voltage in the waveform generation link is too high. Even if the air gap is adjusted to the maximum, it cannot meet the requirements of the output waveform. At this time, the controller returns the message "The set waveform does not meet the requirements, please reset it", and the system is still in standby mode.

[0114] The voltage amplifier in each embodiment of the present invention may be a transformer, or a magnetic coupling structure including an inductor and the like having a magnetic core.

[0115] Embodiment 2

[0116] When the voltage amplifier is Figure 1 In the transformer shown, the telescopic mechanism 4 can be a telescopic mechanism, one end of which is connected to one end of the supporting frame, and the other end of which is connected to the adjustable magnetic core 3 of the transformer.

[0117] like Figure 4 As shown, the process of regulating the air gap of the transformer core may include the following steps S401-S412.

[0118] Step S401, perform Fourier decomposition on the pre-generated voltage u, and take its DC component to obtain U d , set g=0.

[0119] Step S402, determine U d ≥γU m Is it established? If so, execute step S403; otherwise, execute step S406.

[0120] Step S403, determine U d ≥γU max Is it established? If so, wait and return the message "the set waveform does not meet the requirements, please reset"; otherwise, execute step S404.

[0121] Step S404, setting

[0122] Step S405, driving the motor to adjust the air gap.

[0123] Step S406, starting the waveform generator and the voltage amplifier.

[0124] Step S407, determine whether m>m' is established, if so, execute step S408; otherwise, execute step S412.

[0125] Step S408, turning off the waveform generator and the voltage amplifier.

[0126] Step S409, determine g <g max Is it established? If so, execute step S410 and step S405; otherwise, execute step S411.

[0127] Step S411, determine whether m>m' is established, if so, shut down and return the message "transformer is saturated and cannot be applied to the current working condition"; otherwise, execute step S412.

[0128] Step S412, determine whether m=m' is established, if yes, then the machine operates normally and returns "normal operation" information; otherwise, the machine stops and returns "other failure" information.

[0129] Embodiment 3

[0130] When the voltage amplifier is Figure 5 In the transformer shown, the telescopic mechanism 4 can be a telescopic mechanism, one end of which is connected to one end of the supporting frame, and the other end of which is connected to the adjustable magnetic core 3 of the transformer.

[0131] like Figure 4 As shown, the process of regulating the air gap of the transformer core may include steps S401-S412.

[0132] Embodiment 4

[0133] When the voltage amplifier is Figure 6 In the transformer shown, the telescopic mechanism 4 can be two telescopic mechanisms, one end of which is connected to one end of the supporting frame, and the other end of which is connected to the adjustable magnetic core 3 of the transformer.

[0134] like Figure 4 As shown, the process of regulating the air gap of the transformer core may include steps S401-S412.

[0135] In summary, the present invention creatively connects the fixed magnetic core of the voltage amplifier through the first end of the supporting device; connects the adjustable magnetic core of the voltage amplifier through the telescopic mechanism installed at the second end of the supporting device; and performs the following operations through the controller: S1, according to the target output voltage of the target output waveform of the voltage amplifier, obtains the DC voltage component to be input to the voltage amplifier; S2, according to the DC voltage component, obtains the preset air gap value; and S3, when the DC voltage component is greater than or equal to the first voltage threshold and less than the second voltage threshold, controls the motor to drive the telescopic mechanism to extend and retract, so as to adjust the air gap between the adjustable magnetic core and the fixed magnetic core to the preset air gap value. The present invention can actively adjust the magnetic core air gap in the voltage amplifier according to the output voltage requirements, thereby at least partially solving the problem of magnetic core saturation of the voltage amplifier that is easily generated by a wide load variation range and waveform variation, and thus can achieve high voltage multi-waveform output.

[0136] Embodiment 5

[0137] Figure 2FIG. 1 is a structural diagram of a waveform generation system provided by an embodiment of the present invention. Figure 2 As shown, the waveform generating system may include: a signal generator 20; a waveform generator 30; a voltage amplifier 40 for outputting a target output waveform; and the air gap control system 100 for regulating the air gap between the adjustable magnetic core and the fixed magnetic core in the voltage amplifier 40 to a preset air gap value according to the target output voltage of the target output waveform.

[0138] The target output multi-waveform may include but is not limited to sine wave, triangle wave (sawtooth wave), sine wave, trapezoidal wave (square wave), pulse wave and other waveforms.

[0139] The waveform generating system may further include a low voltage power supply 50 , wherein the low voltage power supply 50 provides an operating voltage for the signal generator 20 and provides an input voltage for the waveform generator 30 .

[0140] like Figure 1 As shown, the air gap control system 100 may include a supporting device 1 , a telescopic mechanism 4 , a motor (not shown), and a controller 10 .

[0141] The functions that the signal generator 20 and the waveform generator 30 can perform can be implemented by referring to the prior art, which is not the main improvement of the present invention.

[0142] Specifically, the specific process of generating a multi-waveform high voltage may include the following contents.

[0143] First, the controller 10 issues a waveform output instruction to the signal generator 20, and the signal generator 20 generates an analog signal or a digital signal u=U of the target output waveform. o *N1 / N2, and then the controller 10 obtains the judgment parameter U d According to the above method, when the air gap needs to be adjusted, the controller 10 uses the motor of the voltage amplifier to drive the telescopic mechanism to adjust the size of the air gap of the magnetic core;

[0144] Secondly, the waveform generator 30 converts the analog signal or digital signal input by the signal generation link into a control signal of the power electronic switch, and converts the low-voltage power supply voltage into a target output waveform through a power amplifier circuit.

[0145] Finally, the voltage amplifier 40 performs a final voltage boosting process, so that a high voltage with multiple waveforms is finally output.

[0146] When the system is running, the primary current i will be monitored in real time y and the secondary current i fThe ratio m, if the ratio is too large, it is considered that the primary current of the voltage amplifier in the voltage amplification link is too large, and the voltage amplifier is saturated. The control system shuts down the waveform generating link and the voltage amplification link; if the air gap is less than the maximum air gap value at this time, the air gap will be increased and the waveform generating link and the voltage amplification link will be restarted, and the waveform generating link and the voltage amplification link will be restarted. Otherwise, according to the relationship between m and m', the control system operates normally or shuts down: when m is within the normal range, the system operates normally.

[0147] The present invention determines the parameter U d The pre-protection parameters are set based on the characteristic that the DC component easily causes the voltage amplifier to saturate, which belongs to the "active" protection; the judgment parameter m is a "passive" protection method that uses the phenomenon that after the voltage amplifier is saturated, the input current increases rapidly and the output current decreases or remains unchanged. The two complement each other.

[0148] The purpose of the present invention is to provide a high voltage multi-waveform generating system and an air gap control method, which solves the problem of voltage amplifier core saturation that is easily generated under a wide load variation range and multi-waveform output, thereby realizing high voltage multi-waveform output.

[0149] The present invention can be used in systems that have high requirements on voltage levels and require multi-waveform outputs, such as laboratory theoretical research, biomedical fields, aerospace fields, plasma processing fields, etc.

[0150] Embodiment 6

[0151] The present embodiment provides an air gap control method, which is applied to a voltage amplifier, wherein the voltage amplifier includes a fixed magnetic core and an adjustable magnetic core, wherein the fixed magnetic core is connected to a first end of a supporting device; a telescopic mechanism is installed at a second end of the supporting device, and the telescopic mechanism is connected to the adjustable magnetic core. The air gap control method includes: S1, obtaining a DC voltage component to be input into the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier; S2, obtaining a preset air gap value between the adjustable magnetic core and the fixed magnetic core according to the DC voltage component; and S3, when the DC voltage component is greater than or equal to a first voltage threshold and less than a second voltage threshold, controlling a motor to drive the telescopic mechanism to extend and retract, so as to control the air gap between the adjustable magnetic core and the fixed magnetic core to the preset air gap value.

[0152] Preferably, after executing S3, the air gap control method also includes: S4, starting the waveform generator and the voltage amplifier, and obtaining the ratio of the primary current to the secondary current; and S5, performing the following operations according to the ratio: when the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, turning off the waveform generator and the voltage amplifier, and judging whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than a maximum air gap value, and determining whether to increase the air gap according to the judgment result; when the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier running; or when the ratio is less than the ratio threshold, stopping the waveform generator and the voltage amplifier and feeding back "other faults".

[0153] Preferably, the air gap control method further comprises: executing S4-S5 when the DC voltage component is less than the first voltage threshold.

[0154] Preferably, determining whether to increase the air gap based on the judgment result includes: when the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increasing the air gap, and executing S4-S5 until the ratio is less than or equal to the ratio threshold; or when the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, judging the relationship between the ratio and the ratio threshold, and performing the following operations based on the judgment result: when the ratio is greater than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "voltage amplifier saturation"; when the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier in operation; or when the ratio is less than the ratio threshold, stopping the operation of the waveform generator and the voltage amplifier and feeding back "other faults".

[0155] Preferably, the first voltage threshold is the product of the critical saturation voltage of the voltage amplifier and a preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is 0; and the second voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is a maximum value.

[0156] Preferably, obtaining the DC voltage component to be input into the voltage amplifier includes: obtaining the voltage to be input into the voltage amplifier based on the target output voltage and the ratio of the number of coil turns on the secondary side of the voltage amplifier to the number of coil turns on the primary side; performing Fourier transform on the obtained voltage; and determining the DC component in the voltage after the Fourier transform as the DC voltage component, wherein the target output voltage is greater than a preset voltage.

[0157] For specific details and benefits of the air gap control method provided by the embodiment of the present invention, please refer to the above description of the air gap control system, which will not be repeated here.

[0158] Embodiment 7

[0159] An embodiment of the present invention provides a machine-readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the air gap control method.

[0160] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0161] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0162] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0163] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An air gap control system, characterized in that: The air gap control system comprises: A supporting device, wherein a first end of the supporting device is connected to a fixed magnetic core of the voltage amplifier; a telescopic mechanism, the telescopic mechanism being mounted on the second end of the supporting device and connected to the adjustable magnetic core of the voltage amplifier; A motor, used for driving the telescopic mechanism to extend and retract; and A controller that does the following: S1, obtaining a DC voltage component to be input to the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier; S2, obtaining a preset air gap value according to the DC voltage component; and S3, when the DC voltage component is greater than or equal to the first voltage threshold and less than the second voltage threshold, the air gap between the adjustable magnetic core and the fixed magnetic core is adjusted to the preset air gap value by controlling the motor to drive the telescopic mechanism to extend and retract.

2. The air gap control system according to claim 1, characterized in that: The controller is further configured to perform the following operations after executing S3: S4, starting the waveform generator and the voltage amplifier, and obtaining the ratio of the primary current to the secondary current; and S5, performing the following operations according to the ratio: When the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, the waveform generator and the voltage amplifier are turned off, and it is determined whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than a maximum air gap value, and whether to increase the air gap according to the determination result; When the ratio is equal to the ratio threshold, keeping the waveform generator and the voltage amplifier running; or When the ratio is less than the ratio threshold, the waveform generator and the voltage amplifier are stopped and “other faults” are fed back.

3. The air gap control system according to claim 2, characterized in that: The controller is further configured to execute S4 - S5 when the DC voltage component is less than the first voltage threshold.

4. The air gap control system according to claim 2 or 3, characterized in that: The determining whether to increase the air gap according to the judgment result comprises: When the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increase the air gap, and execute S4-S5 until the ratio is less than or equal to the ratio threshold; or In the case where the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, determining the relationship between the ratio and the ratio threshold, and performing the following operations according to the determination result: When the ratio is greater than the ratio threshold, the waveform generator and the voltage amplifier are stopped and "voltage amplifier saturation" is fed back; When the ratio is equal to the ratio threshold, keep the waveform generator and the voltage amplifier running; or When the ratio is less than the ratio threshold, the waveform generator and the voltage amplifier are stopped and “other faults” are fed back.

5. The air gap control system according to claim 1, characterized in that: The first voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is 0; and the second voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is maximum.

6. The air gap control system according to claim 1, characterized in that: The step of obtaining a DC voltage component to be input to the voltage amplifier comprises: Obtaining a voltage to be input to the voltage amplifier according to the target output voltage and a ratio of the number of turns of the coil on the secondary side of the voltage amplifier to the number of turns of the coil on the primary side; performing Fourier transformation on the acquired voltage; and Determine the DC component in the voltage after Fourier transformation as the DC voltage component, Wherein, the target output voltage is greater than a preset voltage.

7. An air gap control method, characterized in that: Applied to a voltage amplifier, the voltage amplifier comprises a fixed magnetic core and an adjustable magnetic core, wherein the fixed magnetic core is connected to a first end of a supporting device; a telescopic mechanism is installed at a second end of the supporting device, and the telescopic mechanism is connected to the adjustable magnetic core, and the air gap control method comprises: S1, obtaining a DC voltage component to be input to the voltage amplifier according to a target output voltage of a target output waveform of the voltage amplifier; S2, acquiring a preset air gap value between the adjustable magnetic core and the fixed magnetic core according to the DC voltage component; and S3, when the DC voltage component is greater than or equal to the first voltage threshold and less than the second voltage threshold, the air gap between the adjustable magnetic core and the fixed magnetic core is adjusted to the preset air gap value by controlling the motor to drive the telescopic mechanism to extend and retract.

8. The air gap control method according to claim 7, characterized in that: After executing S3, the air gap control method further includes: S4, starting the waveform generator and the voltage amplifier, and obtaining the ratio of the primary current to the secondary current; and S5, performing the following operations according to the ratio: When the ratio is greater than a threshold value of the ratio of the primary current to the secondary current, the waveform generator and the voltage amplifier are turned off, and it is determined whether the air gap between the adjustable magnetic core and the fixed magnetic core is less than a maximum air gap value, and whether to increase the air gap according to the determination result; When the ratio is equal to the ratio threshold, keep the waveform generator and the voltage amplifier running; or When the ratio is less than the ratio threshold, the waveform generator and the voltage amplifier are stopped and “other faults” are fed back.

9. The air gap control method according to claim 8, characterized in that: The air gap control method further includes: executing S4-S5 when the DC voltage component is less than the first voltage threshold.

10. The air gap control method according to claim 8 or 9, characterized in that: The determining whether to increase the air gap according to the judgment result comprises: When the air gap between the adjustable magnetic core and the fixed magnetic core is less than the maximum air gap value, increase the air gap, and execute S4-S5 until the ratio is less than or equal to the ratio threshold; or In the case where the air gap between the adjustable magnetic core and the fixed magnetic core is greater than or equal to the maximum air gap value, determining the relationship between the ratio and the ratio threshold, and performing the following operations according to the determination result: When the ratio is greater than the ratio threshold, the waveform generator and the voltage amplifier are stopped and "voltage amplifier saturation" is fed back; When the ratio is equal to the ratio threshold, keep the waveform generator and the voltage amplifier running; or When the ratio is less than the ratio threshold, the waveform generator and the voltage amplifier are stopped and “other faults” are fed back.

11. The air gap control method according to claim 7, characterized in that: The first voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is 0; and the second voltage threshold is the product of the critical saturation voltage of the voltage amplifier and the preset ratio when the air gap between the adjustable magnetic core and the fixed magnetic core is maximum.

12. The air gap control method according to claim 7, characterized in that: The step of obtaining a DC voltage component to be input to the voltage amplifier comprises: Obtaining a voltage to be input to the voltage amplifier according to the target output voltage and a ratio of the number of turns of the coil on the secondary side of the voltage amplifier to the number of turns of the coil on the primary side; performing Fourier transformation on the acquired voltage; and Determine the DC component in the voltage after Fourier transformation as the DC voltage component, Wherein, the target output voltage is greater than a preset voltage.

13. A waveform generating system, characterized in that: The waveform generating system comprises: Signal generator; Waveform generator; a voltage amplifier for outputting a target output waveform; and The air gap control system according to any one of claims 1 to 6 is used to control the air gap between the adjustable magnetic core and the fixed magnetic core in the voltage amplifier to a preset air gap value according to the target output voltage of the target output waveform.

14. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions, which are used to enable a machine to execute the air gap control method described in any one of claims 7-12.

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