Alternating current synchronous injection type pulse current damping compensation circuit and control method thereof

Abstract

The application discloses an alternating current synchronous injection type pulse current damping compensation circuit and a control method thereof, and belongs to the technical field of high-voltage pulse power. A main discharge circuit of the circuit is formed by series connection of a high-voltage capacitor, a high-voltage switch and a load inductance in sequence. An energy compensation branch is connected in parallel to both ends of the load inductance. The branch comprises an isolation transformer. A primary winding of the isolation transformer is connected in series with a supplementary capacitor and a supplementary switch to form a supplementary resonance circuit. A center tap of a secondary winding of the isolation transformer is grounded. Both ends of the secondary winding are connected to both ends of the load inductance through unidirectional conduction semiconductor devices respectively. The control method precharges the supplementary capacitor to a set voltage value, triggers the high-voltage switch and the supplementary switch at the same time, and generates a resonance current with the same frequency and phase as a damping oscillation current of the main discharge circuit in the energy compensation branch. An induced voltage of the secondary winding of the isolation transformer is automatically rectified through the unidirectional conduction semiconductor devices, and a supplementary current is injected into the load inductance in each half cycle to compensate for circuit loss.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage pulse power technology, specifically relating to an AC synchronous injection pulse current damping compensation circuit and its control method. Background Technology

[0002] In high-voltage pulsed power systems, high-voltage capacitors discharge through high-voltage switches to the load inductor, generating a damped oscillating current, which is widely used in plasma-driven systems, pulse welding, electromagnetic forming, and pulse sterilization. However, due to the internal resistance of the high-voltage switch, the equivalent series resistance of the high-voltage capacitor, and the parasitic resistance of the loop conductors, the amplitude of the oscillating current decays exponentially with the period, a phenomenon known as "pulse current drop." This drop significantly reduces the effective energy of the subsequent half-wave, affecting the processing performance.

[0003] To suppress current sag, existing technologies often employ methods such as increasing capacitor capacity, raising initial voltage, or using series resistor compensation networks. However, these methods suffer from problems such as large size, low efficiency, or complex control. Some solutions attempt to use active energy injection, but these often require complex phase detection and half-wave switching control, resulting in slow response speeds and a tendency to introduce phase errors. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide an AC synchronous injection pulse current damping compensation circuit and its control method. The present invention constructs an auxiliary AC resonant branch with the same resonant period and initial phase as the main discharge circuit. This resonant branch is connected in parallel to the load inductor via the secondary side of an isolation transformer and a bidirectional diode structure. When the main circuit triggers oscillation, the auxiliary branch is triggered simultaneously. The AC current generated by this auxiliary branch automatically injects energy into the load inductor in the same direction as the main circuit current through the transformer and diodes, thereby continuously compensating for circuit losses and significantly mitigating current drops.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An AC synchronous injection pulse current damping compensation circuit includes: The main discharge circuit consists of a high-voltage capacitor. High-voltage switch Load inductance It is formed by connecting them in series; The energy compensation branch is connected in parallel to the load inductor. At both ends, this branch includes supplementary capacitors. Supplementary switch Isolation transformer ; The isolation transformer The primary winding and the supplementary capacitor Supplementary switch The series connection forms a supplementary resonant circuit; The isolation transformer The secondary winding has a center tap and is grounded. The two ends of the secondary winding are connected to the load inductor through unidirectional conducting semiconductor devices. The two ends.

[0006] The isolation transformer The primary winding has an additional inductor connected in series. It is used to precisely match the resonant period.

[0007] The unidirectional semiconductor devices connected to both ends of the secondary winding are diodes, and the two diodes have opposite polarities, forming a bidirectional anti-reverse structure.

[0008] The resonant period of the energy compensation branch and the resonant period of the main discharge circuit satisfy the following: in, For isolation transformer Primary-side equivalent inductance, To supplement the capacitor, For load inductance, It is a high-voltage capacitor.

[0009] The supplementary switch With the high voltage switch The supplementary switch is configured to trigger conduction simultaneously. The topology uses a half-bridge inverter or a full-bridge inverter, supplemented by switches. The devices use semiconductor devices, including silicon carbide, IGBT, thyristor or silicon MOSFET.

[0010] A control method for an AC synchronous injection pulse current damping compensation circuit includes the following steps: Step 1, add the capacitor Precharge to the set voltage value ; Step 2, simultaneously trigger the high-voltage switch to turn on. and supplementary switch ; Step 3: The main discharge circuit generates a damped oscillating current, while the energy compensation branch generates a resonant current of the same frequency and phase. Step 4, Isolation Transformer The secondary-side induced voltage is automatically rectified by two diodes or unidirectional semiconductor devices, and a supplementary current in the same direction as the main discharge circuit current is injected into the load inductor in each half-cycle to compensate for circuit losses.

[0011] The supplementary current is adjusted by the supplementary capacitor. Preset voltage value Controlling the replenishment of energy during each oscillation Through isolation transformer turns ratio Control the load inductance load voltage .

[0012] The voltage value and replenishing energy satisfy: ; The turns ratio With load voltage satisfy: = .

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Natural phase synchronization: This invention uses an energy compensation branch, which triggers the energy compensation branch and the main discharge circuit simultaneously. No additional phase-locked loop, zero-crossing detection or phase adjustment circuit is required, achieving completely synchronous and phase-integrated energy injection, making control extremely simple.

[0014] 2. Fully automatic bidirectional compensation: This invention uses a grounded isolation transformer secondary center tap plus a double reverse diode structure to automatically adapt to the positive and negative half-cycles of AC, without the need for full-bridge rectification or active switching, resulting in low conduction loss and high reliability.

[0015] 3. Effectively suppresses current drop: This invention uses an energy compensation branch to continuously inject energy in each half-cycle, which can significantly compensate for ohmic losses, greatly slow down the decay of pulse current amplitude, extend the effective oscillation time, and improve energy utilization.

[0016] 4. Electrical isolation: This invention isolates the energy compensation branch from the high-voltage side of the main discharge circuit through an isolation transformer, which improves system safety and facilitates the design of low-voltage control circuits.

[0017] 5. Flexible parameter matching: This invention allows for adjustment of the supplementary capacitor. Voltage setting voltage value Additional inductance or isolation transformer connected in series with the primary side The turns ratio can be adapted to main circuits with different frequencies and losses.

[0018] In summary, the compensation circuit proposed in this invention achieves completely synchronous and in-phase energy injection, and is simple to control, has low conduction loss, high reliability, high energy utilization, and flexible parameter matching, thereby improving safety and versatility. Attached Figure Description

[0019] Figure 1This is an electrical block diagram of the compensation circuit of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1 As shown, because of the internal resistance of the main discharge circuit The damping attenuation of the pulse current fails to meet the predetermined target peak current range requirement. Therefore, an energy compensation branch needs to be added to the pulse circuit to maintain the attenuation of the peak current in each cycle, thereby achieving the peak current range attenuation requirement for each cycle. Based on this, the present invention provides an AC synchronous injection pulse current damping compensation circuit, comprising: Main discharge circuit: consisting of a high-voltage capacitor High-voltage switch Load inductance This system, connected in series, is used to generate damped oscillating pulse current; power supply. Connected to high voltage capacitor The two ends.

[0022] Energy compensation branch: connected in parallel to the load inductor At both ends, this branch includes supplementary capacitors. Supplementary switch Isolation transformer Power supply Connected to the supplementary capacitor The two ends.

[0023] The isolation transformer The primary winding and the supplementary capacitor Supplementary switch They are connected in series to form an independent complementary resonant circuit; The isolation transformer The primary winding has an additional inductor connected in series. It is used to precisely match the resonant period.

[0024] The isolation transformer The secondary winding is provided with a center tap, which is grounded; The two ends of the secondary winding are respectively connected to the first diode. Second diode Connected to the load inductor The two ends of the first diode With the second diode The polarities are opposite, forming a bidirectional anti-reverse structure. In other embodiments, a unidirectional conducting semiconductor device can also be used. Specifically, it can be a unidirectional conducting switch, so that regardless of whether the secondary side induced voltage is in the positive or negative half-cycle, a compensation current in the same direction can be injected into the load inductor.

[0025] Furthermore, the resonant period of the energy compensation branch is equal to the resonant period of the main discharge circuit, i.e., it satisfies: in, For isolation transformer Primary-side equivalent inductance, To supplement the capacitor, For load inductance, This is a high-voltage capacitor. The resonant period of the energy compensation branch is equal to the resonant period of the main discharge circuit, ensuring that the supplementary current of the energy compensation branch and the oscillating current of the main discharge circuit always maintain the same frequency and phase.

[0026] Furthermore, the supplementary switch The control method is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] Simultaneous triggering means that both circuits close at the same time. Therefore, the energy compensation branch and the main discharge circuit simultaneously establish oscillations from a zero initial state, naturally maintaining phase consistency, eliminating the need for current zero-crossing detection or additional phase synchronization circuits.

[0027] Furthermore, the supplementary switch The topology uses a half-bridge inverter; in other embodiments, a full-bridge inverter can also be used to supplement the switches. The device uses silicon carbide, and in other embodiments, semiconductor devices such as IGBTs, thyristors, or silicon MOSFETs may also be used.

[0028] Furthermore, the isolation transformer The secondary winding center tap is grounded, and the first diode... The anode is connected to one end of the secondary winding, and the cathode is connected to the load inductor. First terminal; second diode The cathode is connected to the other end of the secondary winding, and the anode is connected to the load inductor. The second terminal. When the secondary-side induced voltage is in the positive half-cycle (the upper terminal is positive), the first diode... When the circuit is turned on, current flows from the upper end of the secondary winding through the first diode. Inductance flowing into the load Then it returns through the center tap; when the secondary-side induced voltage is in the negative half-cycle (the lower end is positive), the second diode... When the circuit is turned on, current flows from the lower end of the secondary side through... Inductance flowing into the load Then it returns via the center tap. Two diodes ensure the load inductance. The direction of the supplementary current obtained in each half-cycle is the same as the direction of the current in the main discharge circuit.

[0029] The control method based on the above circuit includes the following steps: S1, pre-install the supplementary capacitor Charge to the set voltage value (It can be adjusted according to the required compensation energy, and is generally used with high-voltage capacitors) (Voltage equivalent or proportionally set); S2 simultaneously triggers the high-voltage switch that connects the main discharge circuit. Supplemental switch for energy compensation branch ; S3, in the main discharge circuit, high-voltage capacitor via high voltage switch To load inductance Discharge generates damped oscillating current. ; S4, in the energy compensation branch, supplementary capacitor By supplementing the switch To isolation transformer The primary-side equivalent inductance resonates, generating an AC resonant current. The frequency of its AC voltage is related to the damped oscillation current of the main discharge circuit. They are identical because they are triggered simultaneously and have similar initial conditions; S5, Isolation Transformer The secondary side induces an AC voltage of the same frequency, which is grounded through the center tap and two first diodes set in opposite directions. Second diode The rectification effect automatically directs the current to the load inductor in each half-cycle. Inject unidirectional supplemental current This single-phase supplemental current The direction is always the same as the damped oscillating current generated by the main discharge circuit. The same applies, thus compensating for the resistance loss of the main discharge circuit in real time; S6, when the oscillation of the main discharge circuit decays to a preset threshold or after a specified number of cycles, disconnect the high-voltage switch. and supplementary switch The system was reset.

[0030] Optionally, by adjusting the supplementary capacitor Set voltage value Controlled energy injection Through isolation transformer turns ratio Control the load inductance load voltage To match the loss levels of different circuits.

[0031] The voltage value and replenishing energy satisfy: ; The turns ratio With load voltage satisfy: = .

Claims

1. An AC synchronous injection pulse current damping compensation circuit, characterized in that, include: The main discharge circuit consists of a high-voltage capacitor. High-voltage switch Load inductance It is formed by connecting them in series; The energy compensation branch is connected in parallel to the load inductor. At both ends, this branch includes supplementary capacitors. Supplementary switch Isolation transformer ; The isolation transformer The primary winding and the supplementary capacitor Supplementary switch The series connection forms a supplementary resonant circuit; The isolation transformer The secondary winding has a center tap and is grounded. The two ends of the secondary winding are connected to the load inductor through unidirectional conducting semiconductor devices. The two ends.

2. The circuit according to claim 1, characterized in that, The isolation transformer The primary winding has an additional inductor connected in series. It is used to precisely match the resonant period.

3. The circuit according to claim 1, characterized in that, The unidirectional semiconductor devices connected to both ends of the secondary winding are diodes, and the two diodes have opposite polarities, forming a bidirectional anti-reverse structure.

4. The circuit according to claim 1, characterized in that, The resonant period of the energy compensation branch and the resonant period of the main discharge circuit satisfy the following: in, For isolation transformer Primary-side equivalent inductance, To supplement the capacitor, For load inductance, It is a high-voltage capacitor.

5. The circuit according to claim 1, characterized in that, The supplementary switch With the high voltage switch Configured to trigger conduction simultaneously; The supplementary switch The topology uses a half-bridge inverter or a full-bridge inverter, supplemented by switches. The devices use semiconductor devices, including silicon carbide, IGBT, thyristor or silicon MOSFET.

6. A control method based on the circuit according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1, add the capacitor Precharge to the set voltage value ; Step 2, simultaneously trigger the high-voltage switch to turn on. and supplementary switch ; Step 3: The main discharge circuit generates a damped oscillating current, while the energy compensation branch generates a resonant current of the same frequency and phase. Step 4, Isolation Transformer The secondary-side induced voltage is automatically rectified by two diodes or unidirectional semiconductor devices, and a supplementary current in the same direction as the main discharge circuit current is injected into the load inductor in each half-cycle to compensate for circuit losses.

7. The method according to claim 6, characterized in that, The supplementary current is adjusted by the supplementary capacitor. Preset voltage value Controlling the replenishment of energy during each oscillation Through isolation transformer turns ratio Control the load inductance load voltage ; The voltage value and replenishing energy satisfy: ; The turns ratio With load voltage satisfy: = .

Images