Wide range x-ray high voltage power supply system with stepwise closed loop control

Abstract

The application discloses a wide-range X-ray high-voltage power supply system with grading closed-loop control, which comprises a double-path rectification module, an interleaved parallel power factor correction module, an LCC resonant conversion module, a high-frequency voltage-boosting module and a multi-path voltage-boosting rectification module connected in sequence, and further comprises a tube voltage feedback module, a grading tube current sampling module and a control module. The grading tube current sampling module is provided with at least two sampling ranges with different sampling conversion coefficients and a range switching unit, the control module selects the corresponding sampling range according to at least one of a tube current given signal and a tube current feedback signal, and performs closed-loop adjustment according to a tube voltage given signal, a tube voltage feedback signal, the tube current given signal and the tube current feedback signal. Thus, wide-range tube voltage and tube current output are realized, current ripple is reduced, and the efficiency, output stability and short-circuit protection capability of the X-ray high-voltage power supply are improved.

Description

Technical Field

[0001] This invention belongs to the field of X-ray source technology, specifically relating to a wide-range X-ray high-voltage power supply system with graded closed-loop control. Background Technology

[0002] Currently, high-voltage power supplies typically employ series resonant topologies or parallel resonant topologies in high-power applications. Series resonant circuits exhibit large loop currents in the resonant state, which can easily increase current stress and conduction losses in switching devices and resonant elements. Furthermore, when the load varies significantly, they also suffer from poor load adaptability, unstable resonant points, and strong electromagnetic interference.

[0003] Components in parallel resonant circuits typically withstand high voltage stress and suffer from poor start-up characteristics, significant reactive circulating current losses, and difficulties in load regulation. Under high-frequency operating conditions, parasitic parameters such as parasitic inductance, parasitic capacitance, leakage inductance of high-frequency transformers, and distributed capacitance of windings can significantly affect the resonant frequency and gain characteristics, increasing the complexity of circuit design, component selection, and debugging.

[0004] X-ray high-voltage power supplies typically need to operate in the power range of hundreds of watts to kilowatts, with output voltages varying from tens of kilovolts to hundreds of kilovolts, and tube currents ranging from small milliamperes to tens of milliamperes. Existing fixed-range tube current sampling circuits struggle to simultaneously achieve both sampling resolution under low current conditions and input range under high current conditions. This often results in problems such as the low-current feedback signal being significantly affected by noise and zero-point drift, or the high-current feedback signal becoming saturated and distorted.

[0005] Existing technology CN120262844A discloses an inverter drive circuit and a high-voltage generator based on dual closed-loop error compensation. Error compensation is achieved through a kilovolt voltage feedback loop and a resonant current feedback loop, and a PFM drive signal is output to drive an LCC resonant converter. This prior art also implements corresponding over-current protection by acquiring the resonant current and inverter current.

[0006] However, the current sampled by CN120262844A is mainly the resonant current or inverter current in the resonant converter, not the actual tube current of the X-ray tube. The difference between the resonant current and the actual tube current is also affected by factors such as the high-frequency transformer turns ratio, the number of voltage doubler rectifier stages, parasitic parameters, and load conditions, making it difficult to directly reflect the actual tube current changes under different operating conditions. This existing technology also does not set sampling ranges with different sampling conversion coefficients for a wide range of tube currents, and may still suffer from insufficient sampling accuracy for small currents or signal saturation for large currents.

[0007] Furthermore, the protection measures in CN120262844A primarily target resonant current or inverter current exceeding limits. It is difficult to directly determine whether a short circuit or insulation breakdown has occurred in the high-voltage cable, X-ray tube, or voltage multiplier rectifier circuit based solely on changes in the tube voltage and current at the high-voltage output terminal. In the event of a sudden short circuit at the high-voltage output terminal, the energy storage of the resonant components, transformer leakage inductance, and detection transmission delays may result in insufficiently direct fault identification and untimely protection response.

[0008] Meanwhile, existing technologies do not adequately address issues such as loss sharing of AC input-side rectifier devices, input current ripple, power factor, and low-frequency fluctuations of the DC bus. Under high-power operation, the losses and ripple generated on the input side may be transmitted to the subsequent resonant converter circuit, causing high-voltage output fluctuations and increasing the current stress on the power devices.

[0009] Furthermore, the traditional method of obtaining high-voltage DC power by stepping up the voltage with a power frequency transformer and then rectifying it suffers from problems such as large size and weight, low power density, low conversion efficiency, slow dynamic response speed, and insufficient output stability. Therefore, existing X-ray high-voltage power supplies still struggle to simultaneously achieve good conversion efficiency, sampling accuracy, closed-loop stability, load adaptability, and high-voltage output short-circuit protection performance under wide tube voltage, wide tube current, and high power output conditions. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wide-range X-ray high-voltage power supply system with segmented closed-loop control.

[0011] The objective of this invention can be achieved through the following technical solutions: This invention provides a wide-range X-ray high-voltage power supply system with graded closed-loop control, including a dual-channel rectifier module, an interleaved parallel power factor correction module, an LCC resonant converter module, a high-frequency boost module, a multi-channel voltage multiplier rectifier module, a tube voltage feedback module, a graded tube current sampling module, and a control module. The AC input terminal of the dual-channel rectifier module is used to connect to an AC power supply. The dual-channel rectifier module, the interleaved parallel power factor correction module, the LCC resonant converter module, the high-frequency boost module, and the multi-channel voltage multiplier rectifier module are electrically connected in sequence. The multi-channel voltage multiplier rectifier module forms a high-voltage output terminal for connecting to the X-ray tube. The tube voltage feedback module is connected to the high voltage output terminal and is used to collect the tube voltage of the high voltage output terminal and generate a tube voltage feedback signal. The segmented tube current sampling module is connected to the tube current sampling path of the X-ray tube. The segmented tube current sampling module includes at least two sampling ranges with different sampling conversion coefficients and a range switching unit for selecting the sampling range, and is used to generate a tube current feedback signal according to the selected sampling range. The control module is connected to the interleaved parallel power factor correction module, the LCC resonant converter module, the tube voltage feedback module, and the range-segmented tube current sampling module. The control module is used to control the range switching unit to select the corresponding sampling range according to at least one of the tube current given signal and the tube current feedback signal, and to generate a closed-loop control signal according to the tube voltage given signal, the tube voltage feedback signal, the tube current given signal, and the tube current feedback signal to adjust the power transmission capability of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module.

[0012] Furthermore, the dual-channel rectifier module includes a first rectifier bridge and a second rectifier bridge; The first rectifier bridge includes a first rectifier diode, a second rectifier diode, a third rectifier diode, and a fourth rectifier diode. The two AC input terminals of the first rectifier bridge are interconnected and connected to the live wire of the AC power supply. The second rectifier bridge includes a fifth rectifier diode, a sixth rectifier diode, a seventh rectifier diode, and an eighth rectifier diode. The two AC input terminals of the second rectifier bridge are interconnected and connected to the neutral wire of the AC power supply. The positive DC output terminal of the first rectifier bridge is connected to the positive DC output terminal of the second rectifier bridge, and the negative DC output terminal of the first rectifier bridge is connected to the negative DC output terminal of the second rectifier bridge, so as to form the positive DC output terminal and the negative DC output terminal of the dual-channel rectifier module.

[0013] Furthermore, the interleaved parallel power factor correction module includes a first Boost branch, a second Boost branch, and a DC bus capacitor; The first Boost branch includes a first PFC inductor, a first PFC switch, and a first boost diode; the second Boost branch includes a second PFC inductor, a second PFC switch, and a second boost diode. The input terminals of the first Boost branch and the second Boost branch are respectively connected to the positive DC output terminal of the dual-channel rectifier module. The output terminals of the first boost diode and the second boost diode are connected to the positive terminal of the DC bus. The first PFC switch and the second PFC switch are connected to the negative terminal of the DC bus. The DC bus capacitor is connected between the positive terminal and the negative terminal of the DC bus. The control module is used to control the first PFC switch and the second PFC switch to conduct alternately.

[0014] Furthermore, the LCC resonant converter module includes a full-bridge inverter unit and an LCC resonant network; The full-bridge inverter unit includes a first full-bridge switch, a second full-bridge switch, a third full-bridge switch, and a fourth full-bridge switch. The first full-bridge switch and the third full-bridge switch constitute a first bridge arm, and the second full-bridge switch and the fourth full-bridge switch constitute a second bridge arm. The LCC resonant network includes a resonant inductor, a series resonant capacitor, and a parallel resonant capacitor. The midpoint of the first bridge arm is connected to the first input terminal of the high-frequency boost module through the resonant inductor. The midpoint of the second bridge arm is connected to the second input terminal of the high-frequency boost module through the series resonant capacitor. The parallel resonant capacitor is connected between the first input terminal and the second input terminal. The first full-bridge switch and the fourth full-bridge switch constitute a first diagonal switch group, and the second full-bridge switch and the third full-bridge switch constitute a second diagonal switch group. The control module is used to control the first diagonal switch group and the second diagonal switch group to conduct alternately, and to set a turn-off interval during the switching process of the first diagonal switch group and the second diagonal switch group.

[0015] Furthermore, the high-frequency boost module includes at least two high-frequency high-voltage transformers, and the primary windings of the at least two high-frequency high-voltage transformers are respectively connected to the output terminals of the LCC resonant converter module; The multi-channel voltage multiplier rectifier module includes at least two voltage multiplier rectifier branches corresponding to the at least two high-frequency high-voltage transformers, and the secondary windings of each high-frequency high-voltage transformer are connected to the corresponding voltage multiplier rectifier branch. Each of the voltage multiplier rectifier branches includes multiple voltage multiplier diodes and multiple voltage multiplier capacitors, and the output terminals of each of the voltage multiplier rectifier branches are connected to the high voltage output terminal.

[0016] Furthermore, the tube voltage feedback module includes a high-voltage divider sampling network and a tube voltage closed-loop compensation network; The input terminal of the high-voltage divider sampling network is connected to the high-voltage output terminal, and is used to convert the tube voltage of the high-voltage output terminal into a low-voltage sampling signal; The tube voltage closed-loop compensation network includes an error amplifier and a compensation network connected between the output and input of the error amplifier. The input of the error amplifier receives the low-voltage sampling signal and the tube voltage setpoint signal, respectively. The output of the error amplifier is used to output a tube voltage error signal corresponding to the deviation between the tube voltage setpoint signal and the low-voltage sampling signal.

[0017] Furthermore, the at least two sampling ranges include a first sampling range and a second sampling range, and the range switching unit includes a range switching relay, a relay driving transistor, a freewheeling diode, a driving resistor, and a pull-down resistor; The switching contact of the range switching relay is connected between the tube current sampling input terminal, the first sampling range, and the second sampling range, and is used to selectively connect the tube current sampling input terminal to the first sampling range or the second sampling range. One end of the coil of the range switching relay is connected to the relay driving power supply, and the other end of the coil of the range switching relay is connected to the collector of the relay driving transistor. The emitter of the relay driving transistor is connected to the signal ground, and the base of the relay driving transistor is connected to the control module through the driving resistor and to the signal ground through the pull-down resistor. The freewheeling diode is connected in reverse parallel across the coil of the range switching relay.

[0018] Furthermore, the first sampling range is a small current sampling range, the second sampling range is a large current sampling range, and the sampling conversion gain of the small current sampling range is greater than the sampling conversion gain of the large current sampling range. The segmented tube current sampling module also includes a tube current sampling conditioning unit, which includes a tube current sampling operational amplifier, an input resistor, and a feedback resistor. The input terminal of the tube current sampling operational amplifier is connected to the sampling range selected by the range switching unit through the input resistor. The feedback resistor is connected between the output terminal and the inverting input terminal of the tube current sampling operational amplifier. The input side of the tube current sampling operational amplifier is also connected to an input filter network and a transient clamping network.

[0019] Furthermore, the control module includes a controller, a digital-to-analog conversion module, and a drive circuit; The digital-to-analog conversion module is connected to the controller and is used to generate the tube voltage reference signal and the tube current reference signal respectively according to the digital reference output by the controller; The controller is used to select a small current sampling range through the range switching unit when the tube current given signal or the tube current feedback signal represents a small current operating state, and to select a large current sampling range through the range switching unit when the tube current given signal or the tube current feedback signal represents a large current operating state. The controller is further configured to generate the closed-loop control signal based on the deviation between the tube voltage setpoint signal and the tube voltage feedback signal, and the deviation between the tube current setpoint signal and the tube current feedback signal. The drive circuit adjusts the power transmission capability of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module based on the closed-loop control signal.

[0020] Furthermore, it also includes a high-voltage output short-circuit protection module, which is connected to the output terminal of the tube voltage feedback module, the output terminal of the range tube current sampling module, and the control module respectively; The high-voltage output short-circuit protection module is used to determine whether the high-voltage output terminal is in a short-circuit state based on at least one of the tube voltage feedback signal and the tube current feedback signal, and outputs a short-circuit protection signal to the control module when the high-voltage output terminal is in a short-circuit state. The control module is used to block the drive signal of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module in response to the short-circuit protection signal.

[0021] Compared with the prior art, the present invention has the following advantages: (1) Existing fixed-range tube current sampling circuits struggle to simultaneously achieve both low-current sampling accuracy and high-current sampling range, often resulting in insufficient resolution of the low-current feedback signal or saturation of the high-current feedback signal. This invention sets at least two sampling ranges with different sampling conversion coefficients and controls the range switching unit to select the corresponding sampling range based on the tube current given signal or tube current feedback signal, ensuring that the feedback signal maintains an appropriate amplitude across different tube current ranges. This improves the sampling resolution under low-current conditions, avoids signal saturation and distortion under high-current conditions, and reduces closed-loop oscillations caused by feedback gain mismatch during range crossings, enabling the X-ray tube to maintain high tube current control accuracy and stability within the range of approximately 0.1 mA to tens of milliamperes.

[0022] (2) Existing high-voltage power supplies are prone to output voltage fluctuations, steady-state deviations, and dynamic adjustment lags when the load and output setpoints change over a wide range. This invention collects tube voltage and actual tube current separately, and performs closed-loop control based on the tube voltage setpoint signal, tube current setpoint signal, and corresponding feedback signal, enabling the system to adjust power transmission according to the actual operating state of the X-ray tube. This improves output stability over a wide tube voltage range of tens to hundreds of kilovolts, and reduces output overshoot and steady-state error when tube voltage and tube current change simultaneously.

[0023] (3) Existing high-power high-voltage power supplies are prone to large conduction and switching losses in their input rectifiers, power factor correction switches, and inverter switches. This invention employs dual-path rectification to share the input current, uses two Boost branches to operate alternately, and reduces voltage and current overlap during the switching process of the full-bridge switches through LCC resonant transformation. This reduces rectification losses, switching losses, and device temperature rise, and improves the overall conversion efficiency from light load to full load.

[0024] (4) Existing single high-frequency transformers and single-channel voltage doubler rectifier circuits bear significant voltage stress, current stress, and thermal stress when operating at high voltage and high power. This invention sets up at least two high-frequency high-voltage transformers and corresponding voltage doubler rectifier branches, distributing the boost and rectification tasks to multiple branches, reducing the stress and local temperature rise borne by a single transformer, voltage doubler diode, and voltage doubler capacitor, and facilitating the expansion of the system output power to several hundred watts to several kilowatts.

[0025] (5) Existing power factor correction circuits and hard-switching inverter circuits generate large current ripple and switching noise, which can easily interfere with tube voltage and tube current sampling. This invention utilizes the interleaved operation of two Boost branches to partially cancel out the branch ripple, and uses LCC resonant soft switching to reduce switching transients, thereby reducing input current ripple, DC bus fluctuations and electromagnetic interference, and improving the reliability of feedback sampling and closed-loop control.

[0026] (6) The existing high-voltage output side and low-voltage control side have a large potential difference, and abnormal discharge on the high-voltage side may affect the low-voltage power and control circuit. This invention uses a high-frequency high-voltage transformer to achieve electrical isolation between the low-voltage power conversion side and the high-voltage voltage multiplier rectifier side, thereby improving the high-voltage isolation capability while completing the voltage boost, and reducing the impact of high-voltage side abnormalities on the input side and control side.

[0027] (7) When existing high-voltage power supplies only protect based on inverter current or resonant current, it is difficult to directly reflect the short-circuit status of high-voltage cables, voltage multiplier rectifier circuits, or X-ray tubes. This invention identifies high-voltage output short circuits based on at least one of the tube voltage feedback signal and tube current feedback signal, and blocks the drive signals of at least one of the power factor correction module and LCC resonant converter module, which can quickly limit the continued transmission of fault energy and reduce the risk of damage to X-ray tubes, high-voltage cables, voltage multiplier rectifier devices, and high-voltage insulation structures. Attached Figure Description

[0028] Figure 1 This is a block diagram of a resonant high-power, high-efficiency, high-voltage X-ray source system according to an embodiment of the present invention; Figure 2 This is a block diagram illustrating a wide-range transistor voltage implementation method according to an embodiment of the present invention; Figure 3This is a block diagram of a multi-stage tube current sampling system according to an embodiment of the present invention; The reference numerals in the diagram are as follows: D1: First rectifier diode; D2: Second rectifier diode; D3: Third rectifier diode; D4: Fourth rectifier diode; D5: Fifth rectifier diode; D6: Sixth rectifier diode; D7: Seventh rectifier diode; D8: Eighth rectifier diode; L1: First PFC inductor; L2: Second PFC inductor; S1: First PFC switch; S2: Second PFC switch; D9: First boost diode; D10: Second boost diode; Cdc: DC bus capacitor; Q1: First... Full-bridge switch; Q2: Second full-bridge switch; Q3: Third full-bridge switch; Q4: Fourth full-bridge switch; a: Midpoint of the first bridge arm; b: Midpoint of the second bridge arm; Lr: Resonant inductor; Cs: Series resonant capacitor; Cp: Parallel resonant capacitor; T1: First high-frequency high-voltage transformer; T2: Second high-frequency high-voltage transformer; Tm: m-th high-frequency high-voltage transformer; -HV: Negative high-voltage output terminal; In the multi-channel voltage multiplier rectifier module, D11, D12, D21, D2n-3, D2n-2, D2n-1, and D2n represent... The voltage multiplier diodes at each stage, C11, C12, C13, C14, C21, C4n, C12n-3, and C12n-2 represent the voltage multiplier capacitors at each stage, with ellipses indicating intermediate stages and other corresponding branches; C51: first sampling filter capacitor; C52: second sampling filter capacitor; R57: first voltage divider or bias resistor; R59: second voltage divider or bias resistor; R60: first input resistor; R61: second input resistor; TVS3: transient suppression diode; R58: clamping branch resistor; U17A: tube current sampling resistor. Operational amplifier; R62: Feedback resistor; C53: Optional feedback capacitor; K2: Range switching relay; VD1: Freewheeling diode; VT1: Relay driver transistor; R63: Relay drive resistor; R64: Pull-down resistor; IP_From_YouXiang: Tube current sampling input from high-pressure oil tank; IP_C: First range terminal; IP_V: Second range terminal; 5VD: Relay drive power supply; 15VAUX2: Operational amplifier auxiliary power supply; SGND: Signal ground; PE: Protective ground. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] This embodiment provides a wide-range X-ray high-voltage power supply system with segmented closed-loop control. Its purpose is to obtain a wide-range, high-efficiency, and high-power resonant high-voltage output to meet the requirements of X-ray tubes for tube voltage and current under different exposure conditions. Figures 1 to 3 As shown, the system includes a dual-channel rectifier module, an interleaved parallel power factor correction module, an LCC resonant converter module, a high-frequency boost module, a multi-channel voltage multiplier rectifier module, a tube voltage feedback module, a segmented tube current sampling module, and a control module. The dual-channel rectifier module, interleaved parallel power factor correction module, LCC resonant converter module, high-frequency boost module, and multi-channel voltage multiplier rectifier module are electrically connected sequentially. The multi-channel voltage multiplier rectifier module forms the negative high-voltage output terminal -HV for connecting to the X-ray tube. The tube voltage feedback module collects the tube voltage at the negative high-voltage output terminal -HV, and the segmented tube current sampling module collects the actual tube current of the X-ray tube. The control module implements closed-loop control based on the tube voltage setpoint signal, tube voltage feedback signal, tube current setpoint signal, and tube current feedback signal.

[0031] In one specific implementation, the AC power supply is 220V AC mains. The output tube voltage of the system can be adjusted from tens of kilovolts to hundreds of kilovolts, and the output tube current can be adjusted from approximately 0.1mA to tens of milliamperes. The output power covers hundreds of watts to several kilowatts. The above values ​​are used to illustrate that the system can cover a wide operating range and do not constitute a limitation on the rated parameters. For different types of X-ray tubes, different output levels can be obtained by changing the turns ratio of the high-frequency high-voltage transformer, the number of voltage doubler rectifier stages, the resonant parameters, and the set range of the controller.

[0032] like Figure 1 As shown, the dual-channel rectifier module is connected between the AC power supply and the interleaved parallel power factor correction module. The first rectifier bridge includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, and a fourth rectifier diode D4. The two AC input terminals of the first rectifier bridge are interconnected and connected to the live wire L of the AC power supply. The second rectifier bridge includes a fifth rectifier diode D5, a sixth rectifier diode D6, a seventh rectifier diode D7, and an eighth rectifier diode D8. The two AC input terminals of the second rectifier bridge are interconnected and connected to the neutral wire N of the AC power supply. The positive DC output terminals of the first and second rectifier bridges are interconnected to form a positive DC output terminal, and their negative DC output terminals are interconnected to form a negative DC output terminal. This connection method is equivalent to using the corresponding diodes in each rectifier bridge in parallel, allowing each rectifier bridge or rectifier diode group to bear a portion of the input current, thereby improving current carrying capacity, reducing the conduction loss and temperature rise of a single diode, and reducing the requirements for individual high-voltage, high-current rectifier devices.

[0033] In another alternative implementation, the dual-path rectifier module can consist of two sets of discrete rectifier diodes, with the conduction direction of each set of diodes and their common node being parallel to the common node. Figure 1 The diodes inside the rectifier bridge shown have the same conduction direction and common node. Alternatively, two or more diodes can be connected in parallel at each conduction position according to the rated power, and small-value current-sharing resistors can be installed in each parallel branch, or the temperature characteristics of the device's forward voltage drop can be used for current sharing. This implementation facilitates the selection of the number of devices for high power levels and reduces localized heat concentration.

[0034] The interleaved parallel power factor correction module includes a first Boost branch, a second Boost branch, and a DC bus capacitor Cdc. The first Boost branch includes a first PFC inductor L1, a first PFC switch S1, and a first boost diode D9; the second Boost branch includes a second PFC inductor L2, a second PFC switch S2, and a second boost diode D10. The input terminals of the first and second Boost branches are respectively connected to the positive DC output terminals of the dual-channel rectifier module. The output terminals of the first and second boost diodes D9 and D10 are jointly connected to the positive terminal of the DC bus. The first and second PFC switches S1 and S2 are jointly connected to the negative terminal of the DC bus. The DC bus capacitor Cdc is connected between the positive and negative terminals of the DC bus.

[0035] The control module outputs interleaved drive signals to the first PFC switch S1 and the second PFC switch S2. Figure 1 In the two-phase implementation shown, the turn-on times of the two drive signals differ by half a switching cycle, i.e., a phase difference of approximately 180 degrees. The first PFC inductor L1 and the second PFC inductor L2 can use the same or approximately the same inductance, and the two Boost branches share the DC bus capacitor Cdc. Interleaved operation causes the current ripple of the two PFC inductors to partially cancel each other out at the input and DC bus terminals, reducing both input current ripple and DC bus ripple, as well as the current stress on individual PFC switches and boost diodes. In one specific implementation, the control module sets up a current balancing loop to keep the average inductor current difference between the two Boost branches within a preset range. In another implementation, the two branches use matching parameters and are driven by the same controller to generate symmetrical drive signals, achieving approximate current sharing from both hardware parameter and drive timing perspectives.

[0036] For higher power systems, the interleaved parallel power factor correction module can add a third or more boost branches to the first and second boost branches, with the drive signals of each branch being uniformly out of phase within one switching cycle. Increasing the number of branches can further reduce the peak current and thermal load of each branch, while retaining... Figure 1 The two-phase interleaving scheme shown is used as the basic unit.

[0037] The LCC resonant converter module is connected between the DC bus capacitor Cdc and the high-frequency boost module, and includes a full-bridge inverter unit and an LCC resonant network. The full-bridge inverter unit includes a first full-bridge switch Q1, a second full-bridge switch Q2, a third full-bridge switch Q3, and a fourth full-bridge switch Q4. The first full-bridge switch Q1 and the third full-bridge switch Q3 form the first bridge arm, with the midpoint of the first bridge arm being midpoint a; the second full-bridge switch Q2 and the fourth full-bridge switch Q4 form the second bridge arm, with the midpoint of the second bridge arm being midpoint b. The first full-bridge switch Q1 and the fourth full-bridge switch Q4 form the first diagonal switch group, and the second full-bridge switch Q2 and the third full-bridge switch Q3 form the second diagonal switch group.

[0038] The LCC resonant network includes a resonant inductor Lr, a series resonant capacitor Cs, and a parallel resonant capacitor Cp. The midpoint a of the first bridge arm is connected to the first input terminal of the high-frequency boost module via the resonant inductor Lr. The midpoint b of the second bridge arm is connected to the second input terminal of the high-frequency boost module via the series resonant capacitor Cs. The parallel resonant capacitor Cp is connected between the first and second input terminals of the high-frequency boost module. The control module controls the first and second diagonal switch groups to conduct alternately, and sets a turn-off interval when the two diagonal switch groups switch, so that the resonant current charges and discharges the parasitic capacitance of the full-bridge switching transistors within the turn-off interval, providing a zero-voltage turn-on condition for the transistor to be turned on.

[0039] Regarding parameter selection, the resonant inductor Lr, series resonant capacitor Cs, and parallel resonant capacitor Cp jointly determine the gain curve and operating frequency band of the LCC resonant network. In one embodiment, the control module primarily adjusts the transmission power by changing the switching frequency of the full-bridge inverter unit, ensuring the operating frequency is within a region capable of soft switching and with monotonic controllable gain. In another embodiment, the DC bus voltage and switching frequency can be adjusted simultaneously, with the interleaved parallel power factor correction module handling the slower bus voltage adjustment and the LCC resonant converter module handling the faster output adjustment. This latter approach reduces the span of a single frequency adjustment, maintaining high efficiency under both light and full load conditions.

[0040] The high-frequency boost module includes at least two high-frequency high-voltage transformers. Figure 1 The diagram shows a first high-frequency high-voltage transformer T1, a second high-frequency high-voltage transformer T2, and an expandable m-th high-frequency high-voltage transformer Tm. The primary windings of each high-frequency high-voltage transformer are connected to the output terminals of the LCC resonant converter module, and the secondary windings are connected to the corresponding voltage multiplier rectifier branches in the multi-channel voltage multiplier rectifier module. The terminals of the primary windings with the same name are kept consistent, ensuring that each transformer receives in-phase high-frequency excitation. The turns ratio of each transformer can be the same, or it can be set to different values ​​according to the number of stages in the corresponding voltage multiplier rectifier branch and the target output voltage.

[0041] The multi-channel voltage multiplier rectifier module includes at least two voltage multiplier rectifier branches corresponding to each high-frequency high-voltage transformer. Each voltage multiplier rectifier branch includes multiple voltage multiplier diodes and multiple voltage multiplier capacitors, with the voltage multiplier diodes and voltage multiplier capacitors connected in an alternating charging and series superposition manner. Figure 1 For ease of illustration, D11, D12, D21, D2n-3, D2n-2, D2n-1, and D2n represent voltage multiplier diodes at each stage, and C11, C12, C13, C14, C21, C4n, C12n-3, and C12n-2 represent voltage multiplier capacitors at each stage. The ellipsis indicates intermediate stages and other corresponding branches. The same subscript in upper and lower branches indicates components of the same type at corresponding positions; actual devices can be distinguished by combining branch numbers. The high-voltage output terminals of each voltage multiplier rectifier branch are connected together to form the negative high-voltage output terminal -HV. In one embodiment, each branch uses the same turns ratio, the same number of voltage multiplier stages, and matching components, and the branch current difference is reduced through symmetrical arrangement; alternatively, a current-sharing impedance can be set at the low-potential junction of each branch. Multi-channel transformers and multi-channel voltage multiplier rectifier branches distribute the output current and transmission power to multiple branches, which helps to reduce the current stress, power loss and local temperature rise borne by a single high-frequency high-voltage transformer, voltage multiplier diode and voltage multiplier capacitor.

[0042] Tube voltage feedback module, such as Figure 2 As shown, the system includes a high-voltage voltage divider sampling network and a tube voltage closed-loop compensation network. The input of the high-voltage voltage divider sampling network is connected to the negative high-voltage output terminal -HV, converting the high-voltage output into a low-voltage sampling signal according to a preset voltage division ratio. The low-voltage sampling signal, after isolation or conditioning, is input to an error amplifier. The other input of the error amplifier receives the tube voltage reference signal, and the error amplifier outputs a tube voltage error signal corresponding to the deviation between the reference signal and the low-voltage sampling signal. An RC compensation network is connected between the output and input of the error amplifier to set the closed-loop gain, poles and zeros, and bandwidth.

[0043] In one embodiment, the high-voltage divider sampling network consists of multiple high-voltage resistors connected in series within the high-voltage tank. The low-voltage side transmits a low-voltage sampling signal to the control module via an isolation amplifier or opto-isolation circuit. In another embodiment, the high-voltage divider sampling network and the low-voltage conditioning circuit share a common reference on the high-voltage side, and then transmit digital feedback to the controller via an isolated analog-to-digital conversion channel. The former method offers a more intuitive circuit and faster dynamic response, while the latter method reduces common-mode interference encountered during long-distance analog transmission.

[0044] The current sampling module for the baffle tube is as follows Figure 3As shown, the tube current sampling path connecting the X-ray tube includes at least two sampling ranges with different sampling conversion coefficients, a range switching unit, and a tube current sampling conditioning unit. The tube current sampling input terminal IP_From_YouXiang from the high-pressure oil tank is connected to the common contact of the range switching relay K2. The range switching relay K2 selectively connects the tube current sampling input terminal to either the first range terminal IP_C or the second range terminal IP_V. In this embodiment, the first range terminal IP_C corresponds to the small current sampling range, and the second range terminal IP_V corresponds to the large current sampling range. The sampling conversion gain of the small current sampling range is greater than that of the large current sampling range.

[0045] Figure 3 The range switching unit shown includes a range switching relay K2, a freewheeling diode VD1, a relay driver transistor VT1, a relay driver resistor R63, and a pull-down resistor R64. One end of the coil of the range switching relay K2 is connected to the relay driver power supply 5VD, and the other end is connected to the collector of the relay driver transistor VT1. The emitter of the relay driver transistor VT1 is connected to signal ground SGND, and its base is connected to the control module through the relay driver resistor R63 and to signal ground SGND through the pull-down resistor R64. The freewheeling diode VD1 is connected in reverse parallel across the coil of the range switching relay K2 to provide a release path for the induced current when the coil is de-energized.

[0046] Figure 3 The illustrated tube current sampling conditioning unit includes a tube current sampling operational amplifier U17A, a first input resistor R60, a second input resistor R61, and a feedback resistor R62. A first sampling filter capacitor C51 and a second sampling filter capacitor C52 are used to suppress high-frequency noise. A first voltage divider or bias resistor R57 and a second voltage divider or bias resistor R59 are used to form an input bias or voltage divider path. A transient suppression diode TVS3 and a clamping branch resistor R58 constitute a transient clamping network. The sampling signal selected by the range switching relay K2 is input to the tube current sampling operational amplifier U17A via the first input resistor R60 and the second input resistor R61. The feedback resistor R62 is connected between the output terminal and the inverting input terminal of the tube current sampling operational amplifier U17A. Optionally, a feedback capacitor C53 is connected in parallel across the feedback resistor R62 to limit the high-frequency gain of the tube current sampling conditioning unit; when this compensation is not required, the location of the feedback capacitor C53 can be omitted. The tube current sampling operational amplifier U17A is powered by the operational amplifier auxiliary power supply 15VAUX2, and its low-voltage side reference is the signal ground SGND; the protective ground PE is used for grounding the chassis and shielding structure, and is isolated from the signal ground SGND in accordance with the equipment insulation and electromagnetic compatibility requirements, or coupled through a predetermined single-point connection or RC network.

[0047] In a specific range selection method, the controller pre-selects the range based on the tube current input signal: when the input value is in the low current operating range, the range switching relay K2 selects the first range terminal IP_C; when the input value is in the high current operating range, the range switching relay K2 selects the second range terminal IP_V. Using pre-selection of the range based on the input value allows relay switching to be completed before exposure begins, avoiding feedback transients caused by load switching.

[0048] In another range-segmentation method, the controller determines the current operating range based on the tube current feedback signal and sets a hysteresis range near the switching threshold. When the feedback signal continuously exceeds the upper switching threshold for a preset time, the range switches from the low current sampling range to the high current sampling range; when the feedback signal continuously falls below the lower switching threshold for a preset time, the range switches from the high current sampling range to the low current sampling range, where the upper switching threshold is higher than the lower switching threshold. This method can automatically adapt to load changes based on the actual tube current and prevent the range switching relay K2 from repeatedly engaging and disengaging near the threshold.

[0049] The tube current setpoint signal and tube current feedback signal can also be used in combination: the controller first determines the target range based on the setpoint, and then uses the feedback signal to verify whether the current range is appropriate; if the sampled signal is close to the upper limit of the conditioning circuit or below the effective resolution range, range correction is performed. During the switching process, the controller can maintain the tube current feedback value before the switch, temporarily reduce the closed-loop gain, or set a short sampling shielding time, and resume normal closed-loop calculation after the range switching relay K2 contact stabilizes. This processing can reduce the impact of relay contact switching and sudden changes in sampling gain on the closed-loop control.

[0050] The control module includes a controller, a digital-to-analog converter module, and a drive circuit. The digital-to-analog converter module generates transistor voltage and transistor current reference signals based on the digital reference output from the controller. The controller receives the transistor voltage and transistor current feedback signals, generates transistor voltage and current deviations respectively, and generates closed-loop control signals based on the deviations. The drive circuit generates drive signals for the first PFC switch S1, the second PFC switch S2, and the first to fourth full-bridge switches Q1 to Q4 based on the closed-loop control signals.

[0051] In one control implementation, the voltage loop of the interleaved parallel power factor correction module maintains the voltage across the DC bus capacitor Cdc within a preset range. The LCC resonant converter module rapidly adjusts the tube voltage at the negative high-voltage output terminal -HV by changing the switching frequency. The tube current closed loop is used to adjust or limit the power transmission capability of the high-voltage power conversion link. When the actual tube current deviates from the tube current setpoint or reaches the preset limit, the controller changes the operating frequency of the LCC resonant converter module or limits its allowable gain. This method decouples the front-stage bus control from the back-stage high-voltage control and can suppress tube current overshoot while maintaining tube voltage regulation.

[0052] In another control implementation, the tube voltage closed-loop output is used to control the switching frequency of the LCC resonant converter module, and the tube current closed-loop output is used to adjust the DC bus target value of the interleaved parallel power factor correction module; alternatively, the controller uses low-selection, limiting, or priority coordinated control based on the tube voltage and tube current closed-loop outputs to adjust the power transmission capability of the high-voltage power conversion link. This method can achieve coordination between tube voltage stabilization and tube current regulation or limiting, avoiding simultaneous overshoot of high-voltage output and tube current when the X-ray tube load changes abruptly.

[0053] The system also includes a high-voltage output short-circuit protection module. This module is connected to the output of the tube voltage feedback module, the output of the graded tube current sampling module, and the control module. In one determination method, a short circuit is detected at the high-voltage output when the tube voltage feedback signal drops significantly within a short period and the tube current feedback signal exceeds the short-circuit threshold. In another determination method, a short-circuit protection signal is output when either an abnormal drop in tube voltage or an abnormal increase in tube current persists for a set time. The control module responds to the short-circuit protection signal by blocking the drive signals of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module.

[0054] For systems requiring rapid protection, a hardware comparator can directly block the drive enable terminals of the first PFC switch S1, the second PFC switch S2, or the full-bridge switches Q1 to Q4, while simultaneously reporting the fault to the controller. For systems that need to distinguish between X-ray tube discharge and continuous short circuit, a preset shutdown time can be applied after the first fault, followed by a tentative restart with limited power. If the fault recurs, the system will latch and shut down. By combining output-side feedback judgment with drive blocking, the time that resonant components, voltage multiplier capacitors, and high-voltage cables continue to release energy to the fault point can be reduced.

[0055] The high-frequency boost module and multi-channel voltage multiplier rectifier module can be installed inside a high-voltage oil tank filled with insulating oil, while the control module, interleaved parallel power factor correction module, and at least some LCC resonant converter modules can be installed outside the oil tank or in a low-voltage isolation area. The high-frequency high-voltage transformer achieves voltage boosting while simultaneously providing electrical isolation between the low-voltage and high-voltage sides. Pipe voltage feedback and pipe current feedback are transmitted to the control module through an isolation channel, thereby improving high-voltage isolation capability and reducing the impact of abnormal discharges on the high-voltage side on the low-voltage control circuit.

[0056] The working principle of the above circuit is as follows. After the system is powered on, the control module first initializes the setpoint, range status, and protection status. After confirming that there is no short circuit fault at the negative high voltage output terminal -HV, it enables the dual-channel rectifier module and the interleaved parallel power factor correction module. The dual-channel rectifier module performs full-wave rectification on the AC input, and the interleaved parallel power factor correction module boosts and stabilizes the rectified voltage to the DC bus capacitor Cdc. At the same time, it makes the AC input current follow the AC input voltage to improve the power factor and reduce harmonic interference to the power grid.

[0057] When the AC power supply operates in the positive half-cycle, the current flows from the AC input terminal through the first rectifier diode D1 and the second rectifier diode D2 to the downstream load, and then forms a loop through the seventh rectifier diode D7 and the eighth rectifier diode D8. At this time, the third rectifier diode D3, the fourth rectifier diode D4, the fifth rectifier diode D5, and the sixth rectifier diode D6 are in the off state. When the AC power supply operates in the negative half-cycle, the current flows through the fifth rectifier diode D5 and the sixth rectifier diode D6 to the downstream load, and then forms a loop through the third rectifier diode D3 and the fourth rectifier diode D4. At this time, the first rectifier diode D1, the second rectifier diode D2, the seventh rectifier diode D7, and the eighth rectifier diode D8 are in the off state. Through this alternating conduction path, the diodes in each rectifier bridge share the input current, reducing the conduction losses of individual diodes and the heating of the rectifier.

[0058] The voltage and current after dual-path rectification enter the interleaved parallel power factor correction module. The first PFC inductor L1, the first PFC switch S1, the first boost diode D9, and the DC bus capacitor Cdc constitute the first Boost branch; the second PFC inductor L2, the second PFC switch S2, the second boost diode D10, and the DC bus capacitor Cdc constitute the second Boost branch. The two Boost branches share the DC bus capacitor Cdc, and the turn-on times of the first PFC switch S1 and the second PFC switch S2 differ by half a switching cycle. The inductor currents of the two branches are interleaved, partially canceling the input current ripple near the switching frequency and its harmonics, as well as the high-frequency ripple of the DC bus, while simultaneously increasing power density and reducing the current stress on individual branches. The double-frequency bus fluctuations generated by single-phase AC rectification are mainly suppressed by the DC bus capacitor Cdc and the bus voltage control loop.

[0059] The DC bus capacitor Cdc supplies power to the LCC resonant converter module. The control module alternately drives the first and second diagonal switch groups to convert the DC bus voltage into a high-frequency square wave voltage applied between the midpoint a of the first bridge arm and the midpoint b of the second bridge arm. This high-frequency square wave voltage, after passing through the LCC resonant network formed by the resonant inductor Lr, the series resonant capacitor Cs, and the parallel resonant capacitor Cp, transfers energy to the first high-frequency high-voltage transformer T1, the second high-frequency high-voltage transformer T2, and so on, up to the m-th high-frequency high-voltage transformer Tm. The LCC topology has two degrees of freedom for adjustment: frequency regulation and resonant parameter design, enabling a wide adjustable range under both light and full load conditions. The parallel resonant capacitor Cp participates in the resonance and shares the voltage across the primary side of the high-frequency high-voltage transformer, which helps reduce the high-voltage stress on the primary side. Compared to using only a single series or parallel resonant network, the LCC resonant network is more suitable for wide load ranges and high-voltage applications.

[0060] Within one positive half-cycle, the LCC resonant converter module sequentially experiences the following operating modes. Before the first operating mode begins, the second full-bridge switch Q2 and the third full-bridge switch Q3 are already off, while the first full-bridge switch Q1 and the fourth full-bridge switch Q4 are not yet on, and the resonant current is still negative. As the parasitic capacitance of the first full-bridge switch Q1 and the fourth full-bridge switch Q4 completes discharge, their anti-parallel parasitic diodes conduct, clamping the drain-source voltage of the switches to near zero. Under this condition, the first full-bridge switch Q1 and the fourth full-bridge switch Q4 turn on, thus achieving zero-voltage turn-on. At this time, the voltage at the input of the high-frequency boost module is clamped by the secondary-side reflected voltage, and the resonant network transfers energy from the primary side to the secondary side. When the polarity of the secondary side of the high-frequency high-voltage transformer is positive at the bottom and negative at the top, the odd-numbered voltage multiplier capacitors in the voltage multiplier rectifier branch are charged, and the even-numbered voltage multiplier capacitors provide energy to the load.

[0061] In the second operating mode, the DC bus capacitor Cdc provides energy to the LCC resonant network through the full-bridge inverter unit. The resonant current gradually changes from negative to positive and continues to increase, causing the resonant inductor Lr, series resonant capacitor Cs, and parallel resonant capacitor Cp to resonate. While the parallel resonant capacitor Cp is still charging, the resonant current mainly flows into it, and the current flowing through the primary side of the high-frequency high-voltage transformer is relatively small, temporarily weakening the energy transfer between the primary and secondary sides. At this time, the load in the voltage doubler rectifier branch is powered by multiple even-numbered voltage doubler capacitors connected in series.

[0062] In the third operating mode, after the parallel resonant capacitor Cp is charged to the clamping voltage corresponding to the secondary side reflected voltage, the current flowing into the parallel resonant capacitor Cp decreases, and the resonant current begins to flow mainly to the primary side of the high-frequency high-voltage transformer. The primary and secondary sides regain coupling, and the secondary side receives energy transferred by the LCC resonant network. The voltage multiplier diodes in the voltage multiplier rectifier branch charge the even-numbered subscript voltage multiplier capacitors, while the odd-numbered subscript voltage multiplier capacitors, which completed charging in the previous stage, provide energy to the load to maintain the voltage at the negative high-voltage output terminal -HV.

[0063] In the fourth operating mode, the first full-bridge switch Q1 and the fourth full-bridge switch Q4 are off, while the second full-bridge switch Q2 and the third full-bridge switch Q3 are not yet turned on, and the resonant current remains positive. The parasitic capacitances of the first full-bridge switch Q1 and the fourth full-bridge switch Q4 begin to charge, while the parasitic capacitances of the second full-bridge switch Q2 and the third full-bridge switch Q3 begin to discharge. When the voltage across the second full-bridge switch Q2 and the third full-bridge switch Q3 drops to near zero, their anti-parallel parasitic diodes turn on, creating conditions for the zero-voltage turn-on of the second full-bridge switch Q2 and the third full-bridge switch Q3 in the next stage. In this mode, the voltage polarity of the primary side of the high-frequency high-voltage transformer has not changed, so the voltage doubler rectifier branch maintains the power supply state of the previous mode. Subsequently, the second diagonal switch group turns on, and the system experiences the corresponding resonance and voltage doubler charging process with opposite polarity.

[0064] Through the aforementioned alternating operation, the multi-stage voltage multiplier diodes and multi-stage voltage multiplier capacitors alternately charge the odd-numbered and even-numbered subscript voltage multiplier capacitors in adjacent half-cycles, and the charged capacitor banks continuously supply power to the load. Multiple high-frequency high-voltage transformers and their corresponding voltage multiplier rectifier branches together form the required high-power X-ray high-voltage output. Depending on the target voltage and power, two high-frequency high-voltage transformers and two voltage multiplier rectifier branches can be used, or more high-frequency high-voltage transformers and corresponding multiple voltage multiplier rectifier branches can be formed.

[0065] The working process of the tube voltage closed loop is as follows Figure 2 As shown, the controller generates a tube voltage setpoint signal through a digital-to-analog converter module. A high-voltage divider sampling network converts the actual tube voltage at the negative high-voltage output terminal (-HV) into a low-voltage sampling signal. An error amplifier compares the tube voltage setpoint signal with the low-voltage sampling signal and outputs a tube voltage error signal via a compensation network. The controller or closed-loop regulation circuit adjusts the target bus value of the interleaved parallel power factor correction module, the switching frequency of the LCC resonant converter module, or at least one of these based on the tube voltage error signal, making the actual tube voltage approach the setpoint value. Because the LCC resonant network can adjust its gain over a wide frequency range, combined with DC bus regulation, a wide range of tube voltage outputs from tens to hundreds of kilovolts can be achieved.

[0066] The tube current closed-loop and range switching process is as follows: Figure 3 As shown, the controller generates a tube current setpoint signal through a digital-to-analog converter module and determines whether the system is operating in a low-current or high-current state based on the tube current setpoint signal or the current tube current feedback signal. When the system detects a low-current operating state, the controller activates the first range terminal IP_C via the range switching relay K2 to obtain a tube current feedback signal with sufficient amplitude using a higher sampling conversion gain. When the system detects a high-current operating state, the controller activates the second range terminal IP_V via the range switching relay K2 to expand the input range using a lower sampling conversion gain and avoid saturation of the tube current sampling operational amplifier U17A. The tube current feedback signal is compared with the tube current setpoint signal to form the tube current deviation, which participates in the closed-loop regulation of the LCC resonant converter module or the interleaved parallel power factor correction module, thereby achieving a wide-range closed-loop output of the tube current.

[0067] When a short circuit or abnormal discharge occurs at the high-voltage output terminal, connecting cable, or X-ray tube, the tube voltage feedback signal at the negative high-voltage output terminal (-HV) drops rapidly, while the tube current feedback signal may rise simultaneously. Based on these signals, the high-voltage output short-circuit protection module generates a short-circuit protection signal. The control module immediately blocks the drive signals of the first PFC switch S1 and the second PFC switch S2, as well as the drive signals of the first to fourth full-bridge switches Q1 to Q4, or first blocks the full-bridge drive and then turns off the PFC drive to prevent the preceding stage from continuing to transfer energy to the fault point. After the fault is cleared and the reset conditions are met, the system can be manually reset or restarted with power limiting after a delay.

[0068] Therefore, this implementation improves input current carrying capacity and reduces rectification losses through a dual-path rectification scheme, enhances the power factor and reduces input and bus ripple through interleaved parallel power factor correction modules, reduces full-bridge switching losses through the soft-switching properties of the LCC resonant network, achieves high voltage and high power output through multiple high-frequency high-voltage transformers and multiple voltage multiplier rectifier branches, and realizes wide-range high voltage and current output through given tube voltage, given tube current, tube voltage feedback, range-divided tube current feedback, and automatic range switching. The system can balance high efficiency, low component stress, high voltage isolation capability, electromagnetic compatibility, and high voltage output short-circuit protection capability.

[0069] The above are merely exemplary embodiments of the present invention. Those skilled in the art can adjust or replace the number of rectifier devices, the number of interleaved branches, the LCC resonant parameters, the number of transformers, the number of voltage multiplier stages, the number of sampling ranges, the range switching devices, and the division of labor in closed-loop control without departing from the core concept of the present invention; such adjustments or replacements, as long as they still employ segmented tube current sampling combined with tube voltage and tube current feedback for closed-loop control of the high-voltage power conversion link, should all be included within the protection scope of the present invention.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wide-range X-ray high-voltage power supply system with segmented closed-loop control, characterized in that, It includes a dual-channel rectifier module, an interleaved parallel power factor correction module, an LCC resonant converter module, a high-frequency boost module, a multi-channel voltage multiplier rectifier module, a tube voltage feedback module, a range-divided tube current sampling module, and a control module; The AC input terminal of the dual-channel rectifier module is used to connect to an AC power supply. The dual-channel rectifier module, the interleaved parallel power factor correction module, the LCC resonant converter module, the high-frequency boost module, and the multi-channel voltage multiplier rectifier module are electrically connected in sequence. The multi-channel voltage multiplier rectifier module forms a high-voltage output terminal for connecting to the X-ray tube. The tube voltage feedback module is connected to the high voltage output terminal and is used to collect the tube voltage of the high voltage output terminal and generate a tube voltage feedback signal. The segmented tube current sampling module is connected to the tube current sampling path of the X-ray tube. The segmented tube current sampling module includes at least two sampling ranges with different sampling conversion coefficients and a range switching unit for selecting the sampling range, and is used to generate a tube current feedback signal according to the selected sampling range. The control module is connected to the interleaved parallel power factor correction module, the LCC resonant converter module, the tube voltage feedback module, and the range-segmented tube current sampling module. The control module is used to control the range switching unit to select the corresponding sampling range according to at least one of the tube current given signal and the tube current feedback signal, and to generate a closed-loop control signal according to the tube voltage given signal, the tube voltage feedback signal, the tube current given signal, and the tube current feedback signal to adjust the power transmission capability of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module.

2. The wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The dual-path rectifier module includes a first rectifier bridge and a second rectifier bridge; The first rectifier bridge includes a first rectifier diode, a second rectifier diode, a third rectifier diode, and a fourth rectifier diode. The two AC input terminals of the first rectifier bridge are interconnected and connected to the live wire of the AC power supply. The second rectifier bridge includes a fifth rectifier diode, a sixth rectifier diode, a seventh rectifier diode, and an eighth rectifier diode. The two AC input terminals of the second rectifier bridge are interconnected and connected to the neutral wire of the AC power supply. The positive DC output terminal of the first rectifier bridge is connected to the positive DC output terminal of the second rectifier bridge, and the negative DC output terminal of the first rectifier bridge is connected to the negative DC output terminal of the second rectifier bridge, so as to form the positive DC output terminal and the negative DC output terminal of the dual-channel rectifier module.

3. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The interleaved parallel power factor correction module includes a first Boost branch, a second Boost branch, and a DC bus capacitor; The first Boost branch includes a first PFC inductor, a first PFC switch, and a first boost diode; the second Boost branch includes a second PFC inductor, a second PFC switch, and a second boost diode. The input terminals of the first Boost branch and the second Boost branch are respectively connected to the positive DC output terminal of the dual-channel rectifier module. The output terminals of the first boost diode and the second boost diode are connected to the positive terminal of the DC bus. The first PFC switch and the second PFC switch are connected to the negative terminal of the DC bus. The DC bus capacitor is connected between the positive terminal and the negative terminal of the DC bus. The control module is used to control the first PFC switch and the second PFC switch to conduct alternately.

4. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The LCC resonant converter module includes a full-bridge inverter unit and an LCC resonant network; The full-bridge inverter unit includes a first full-bridge switch, a second full-bridge switch, a third full-bridge switch, and a fourth full-bridge switch. The first full-bridge switch and the third full-bridge switch constitute a first bridge arm, and the second full-bridge switch and the fourth full-bridge switch constitute a second bridge arm. The LCC resonant network includes a resonant inductor, a series resonant capacitor, and a parallel resonant capacitor. The midpoint of the first bridge arm is connected to the first input terminal of the high-frequency boost module through the resonant inductor. The midpoint of the second bridge arm is connected to the second input terminal of the high-frequency boost module through the series resonant capacitor. The parallel resonant capacitor is connected between the first input terminal and the second input terminal. The first full-bridge switch and the fourth full-bridge switch constitute a first diagonal switch group, and the second full-bridge switch and the third full-bridge switch constitute a second diagonal switch group. The control module is used to control the first diagonal switch group and the second diagonal switch group to conduct alternately, and to set a turn-off interval during the switching process of the first diagonal switch group and the second diagonal switch group.

5. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The high-frequency boost module includes at least two high-frequency high-voltage transformers, and the primary windings of the at least two high-frequency high-voltage transformers are respectively connected to the output terminals of the LCC resonant converter module. The multi-channel voltage multiplier rectifier module includes at least two voltage multiplier rectifier branches corresponding to the at least two high-frequency high-voltage transformers, and the secondary windings of each high-frequency high-voltage transformer are connected to the corresponding voltage multiplier rectifier branch. Each of the voltage multiplier rectifier branches includes multiple voltage multiplier diodes and multiple voltage multiplier capacitors, and the output terminals of each of the voltage multiplier rectifier branches are connected to the high voltage output terminal.

6. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The tube voltage feedback module includes a high-voltage divider sampling network and a tube voltage closed-loop compensation network. The input terminal of the high-voltage divider sampling network is connected to the high-voltage output terminal, and is used to convert the tube voltage of the high-voltage output terminal into a low-voltage sampling signal; The tube voltage closed-loop compensation network includes an error amplifier and a compensation network connected between the output and input of the error amplifier. The input of the error amplifier receives the low-voltage sampling signal and the tube voltage setpoint signal, respectively. The output of the error amplifier is used to output a tube voltage error signal corresponding to the deviation between the tube voltage setpoint signal and the low-voltage sampling signal.

7. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, The at least two sampling ranges include a first sampling range and a second sampling range, and the range switching unit includes a range switching relay, a relay driving transistor, a freewheeling diode, a driving resistor, and a pull-down resistor; The switching contact of the range switching relay is connected between the tube current sampling input terminal, the first sampling range, and the second sampling range, and is used to selectively connect the tube current sampling input terminal to the first sampling range or the second sampling range. One end of the coil of the range switching relay is connected to the relay driving power supply, and the other end of the coil of the range switching relay is connected to the collector of the relay driving transistor. The emitter of the relay driving transistor is connected to the signal ground, and the base of the relay driving transistor is connected to the control module through the driving resistor and to the signal ground through the pull-down resistor. The freewheeling diode is connected in reverse parallel across the coil of the range switching relay.

8. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 7, characterized in that, The first sampling range is a small current sampling range, and the second sampling range is a large current sampling range. The sampling conversion gain of the small current sampling range is greater than that of the large current sampling range. The segmented tube current sampling module also includes a tube current sampling conditioning unit, which includes a tube current sampling operational amplifier, an input resistor, and a feedback resistor. The input terminal of the tube current sampling operational amplifier is connected to the sampling range selected by the range switching unit through the input resistor. The feedback resistor is connected between the output terminal and the inverting input terminal of the tube current sampling operational amplifier. The input side of the tube current sampling operational amplifier is also connected to an input filter network and a transient clamping network.

9. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 8, characterized in that, The control module includes a controller, a digital-to-analog conversion module, and a drive circuit. The digital-to-analog conversion module is connected to the controller and is used to generate the tube voltage reference signal and the tube current reference signal respectively according to the digital reference output by the controller; The controller is used to select a small current sampling range through the range switching unit when the tube current given signal or the tube current feedback signal represents a small current operating state, and to select a large current sampling range through the range switching unit when the tube current given signal or the tube current feedback signal represents a large current operating state. The controller is further configured to generate the closed-loop control signal based on the deviation between the tube voltage setpoint signal and the tube voltage feedback signal, and the deviation between the tube current setpoint signal and the tube current feedback signal. The drive circuit adjusts the power transmission capability of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module based on the closed-loop control signal.

10. A wide-range X-ray high-voltage power supply system with segmented closed-loop control according to claim 1, characterized in that, It also includes a high-voltage output short-circuit protection module, which is connected to the output terminal of the tube voltage feedback module, the output terminal of the graded tube current sampling module, and the control module respectively. The high-voltage output short-circuit protection module is used to determine whether the high-voltage output terminal is in a short-circuit state based on at least one of the tube voltage feedback signal and the tube current feedback signal, and outputs a short-circuit protection signal to the control module when the high-voltage output terminal is in a short-circuit state. The control module is used to block the drive signal of at least one of the interleaved parallel power factor correction module and the LCC resonant converter module in response to the short-circuit protection signal.

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