A Fast Startup Method for a Multi-module LCC High-voltage Power Supply

Abstract

The present invention discloses a method for rapid start-up of a multi-module LCC high-voltage power supply. The method includes: obtaining the initial start-up current values of each module of the LCC resonant converter, and calculating the initial start-up periods of each module; sampling the input voltage value, output voltage value and total output voltage of each module of the LCC resonant converter after the end of the initial start-up period, and calculating the trajectory start-up current values of each module; calculating the switching periods of each module according to the input voltage value, output voltage value and trajectory start-up current value of each module, and performing rapid start-up on each module until the output voltage values of each module reach the set threshold value, and uniformly setting the switching frequencies of each module; sampling the output voltage of each module, the total output voltage and the phase difference of the resonant current between two adjacent modules, and performing PI voltage equalization, PI frequency modulation and PI phase control on the output voltage of each module, the total output voltage and the phase difference of the resonant current between two adjacent modules, so as to perform voltage stabilization, voltage equalization and ripple cancellation on each module.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly relates to a method for quickly starting a multi-module LCC high-voltage power supply. Background Art

[0002] The multi-module LCC high-voltage power supply is a topological structure different from the traditional single-module LCC high-voltage power supply. It combines multiple single-module high-voltage power supplies, with parallel inputs and series outputs, so as to achieve the purpose of outputting higher voltage and greater power.

[0003] As the core component of the X-ray equipment, the performance of the high-voltage power supply directly determines the actual working effect of the X-ray equipment. Lower output voltage ripple means more stable X-ray energy, which can significantly improve the actual working effect of the rays; faster startup speed means less soft rays that are harmful and useless to the human body, and more complex working modes can be achieved. The multi-module LCC high-voltage power supply, through the series connection of multiple modules, reduces the output voltage and withstand voltage requirements of a single module, and at the same time, it is easier to achieve high-voltage output compared with a single-module power supply. In addition, through phase control between modules, the output ripples of the converters can be made to cancel each other out, significantly improving its ripple index.

[0004] However, due to the uneven parameters between modules, it is difficult for the multi-module LCC high-voltage power supply to only consider quick start like a single module, and the voltage equalization ability needs to be considered during the start-up process. The traditional PI control is limited by its low loop bandwidth and cannot achieve quick start. For example, the fuzzy control method proposed in Chinese Patent CN201410447446.9 can improve the stability and response speed of a single-module high-voltage power supply, but it cannot achieve quick start and voltage equalization of multiple modules. Another example is the multi-segment PI control method proposed in Chinese Patent CN201911141805.7, which also cannot achieve voltage equalization synchronously under the condition of quick start. Traditional methods are all limited by the bandwidth of closed-loop control and are difficult to achieve quick start. Summary of the Invention

[0005] In view of this, the present invention provides a method for quickly starting a multi-module LCC high-voltage power supply. This method adjusts the maximum current value during the start-up process by using the degree of voltage inequality, and achieves voltage equalization while ensuring quick start.

[0006] The present invention provides a method for rapid startup of a multi-module LCC high-voltage power supply. The method includes: obtaining the target gear and the initial startup current value required for each module LCC resonant converter, and calculating the initial startup period of each module LCC resonant converter; sampling the input voltage value, output voltage value and total output voltage of each module LCC resonant converter after the end of the initial startup period, and calculating the trajectory startup current value of each module LCC resonant converter according to the output voltage value and the total output voltage of each module LCC resonant converter; calculating the switching period of each module according to the input voltage value and the trajectory startup current value of each module LCC resonant converter, and performing rapid startup on each module until the output voltage value of each module LCC resonant converter reaches a set threshold value, and uniformly setting the switching frequency of each module; sampling the output voltage, total output voltage and phase difference of the resonant current between adjacent two modules of each module LCC resonant converter, and obtaining the steady-state control value of each module after PI voltage equalization control, PI frequency modulation control and PI phase control of the output voltage, total output voltage and phase difference of the resonant current between adjacent two modules of each module LCC resonant converter, so as to perform voltage stabilization, voltage equalization and ripple cancellation on each module.

[0007] Further, the calculation method of the trajectory startup current value of each module LCC resonant converter is: sampling the output voltage value and the total output voltage of each module LCC resonant converter after the end of the initial startup period, and dividing the total output voltage by the number of modules to obtain the average output voltage; after PI control of the error between the output voltage value of each module LCC resonant converter and the average output voltage, obtaining the startup current correction amount; adding the startup current correction amount to the initial startup current value required for each module LCC resonant converter, to obtain the trajectory startup current value of each module LCC resonant converter.

[0008] Further, the step of calculating the switching period of each module according to the input voltage value, output voltage value and trajectory startup current value of each module LCC resonant converter, and performing rapid startup on each module until the output voltage value of each module LCC resonant converter reaches a set threshold value includes: calculating the switching period of each module according to the input voltage value and the trajectory startup current value of each module LCC resonant converter, and performing rapid startup on each module; collecting the output voltage value of each module LCC resonant converter in real time, and judging whether the output voltage value of each module LCC resonant converter reaches a set threshold value; if the output voltage value of each module LCC resonant converter reaches a set threshold value, then closing the switching period calculation, and setting the operating frequency of each module LCC resonant converter to the same frequency.

[0009] Further, the same frequency is the average value of the operating frequencies of each module in the previous switching period.

[0010] Further, the steady-state control value includes the switching frequency. The steps of obtaining the switching frequencies of each module after PI frequency modulation control of the total output voltage are as follows: calculating the error between the total output voltage and the set command voltage, and obtaining the corresponding switching frequencies of each module after PI frequency modulation control of the error to stabilize the voltage of each module.

[0011] Further, the steady-state control value includes the first phase shift angle. The steps of obtaining the first phase shift angle of each module after PI voltage equalization control of the output voltage of each module's LCC resonant converter are as follows: calculating the error between the output voltage of each module's LCC resonant converter and the average output voltage obtained by dividing the total output voltage by the number of modules; obtaining the first phase shift angle of each module's LCC resonant converter after PI voltage equalization control of the error to equalize the voltage of each module.

[0012] Further, the steady-state control value includes the second phase shift angle. The steps of obtaining the second phase shift angle of each module after PI phase control of the phase difference of the resonant current between adjacent two modules are as follows: calculating the error between the phase difference of the resonant current between adjacent two modules and the result of dividing π by the number of modules, and obtaining the second phase shift angle of each module after PI phase control of the error to cancel the ripple of each module.

[0013] Further, the multi-module LCC high-voltage power supply is composed of multiple single-module high-voltage power supplies, and the inputs of each single module are connected in parallel and the outputs are connected in series.

[0014] The above multi-module LCC high-voltage power supply fast start method obtains the switching period of fast start through state trajectory control to ensure that the power supply starts in the fast start mode. Through the voltage feedback method, the gain deviation between different modules is fed back to ensure that each module can start at a relatively fast speed and the same speed, which not only ensures the start speed but also avoids the problem of uneven voltage during the start process. When the start stage is completed, different modules switch to the average operating frequency point between modules, and at the same time, the voltage stabilization control loop, voltage equalization control loop, and phase control loop are turned on. After that, the converters between different modules switch to the steady-state operating mode, realizing voltage equalization through the voltage equalization loop, reducing ripple through the phase control loop, and stabilizing voltage through the voltage stabilization control loop. Description of the Drawings

[0015] For purposes of illustration and not limitation, the present invention will now be described with reference to the preferred embodiments of the present invention, particularly with reference to the accompanying drawings, in which:

[0016] Figure 1 is a schematic diagram of the topological structure of a multi-module LCC high-voltage power supply.

[0017] Figure 2 is a flowchart of a multi-module LCC high-voltage power supply fast start method provided by an embodiment of the present invention.

[0018] Figure 3 It is a trajectory diagram for the initial trajectory startup phase.

[0019] Figure 4 It is a control logic diagram for the fast startup phase.

[0020] Figure 5 It is a state trajectory diagram for the fast startup phase. Detailed implementation manners

[0021] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0022] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0024] Figure 1 It is a circuit topology diagram of a multi-module LCC high-voltage power supply. As Figure 1 shown, the multi-module LCC high-voltage power supply includes an LCC resonant transformer of multiple modules, V o is the output voltage of the LCC resonant transformer, V in is the input voltage of the LCC resonant transformer, n is the external gain ability of the LCC resonant transformer excluding its own gain ability, usually the product of the resonant transformer turns ratio and the voltage multiplication factor of the rectifier circuit, which is the transformer turns ratio in the figure, L r is the series resonant inductor of the LCC resonant transformer, C p is the parallel resonant capacitor of the LCC resonant transformer, C r is the series resonant capacitor of the LCC resonant transformer. Those without numerical subscripts above are all standard values of the parameters, usually the nominal values of the devices. There are usually certain deviations between the actual parameters of each module and the standard values. Auxiliary subscripts are added to the parameters for distinction, such as L r1 , and those with subscript 1 are the corresponding parameters of the 1-module LCC resonant transformer.

[0025] Figure 2It is a flowchart of a fast startup method for a multi-module LCC high-voltage power supply provided by an embodiment of the present invention. The multi-module LCC high-voltage power supply is composed of multiple single-module LCC resonant converters, with the inputs in parallel and the outputs in series.

[0026] As Figure 2 shown, the specific implementation process of the fast startup method for the multi-module LCC high-voltage power supply is as follows:

[0027] S100, Obtain the target gear data and the initial startup current value required for each module LCC resonant converter, and calculate the initial startup period of each module LCC resonant converter.

[0028] In this embodiment, the initial startup current value refers to the maximum current value of the resonant cavity of the LCC resonant converter, and this value is usually the maximum current peak that the front-stage H-bridge of the LCC resonant converter can output.

[0029] There is a set of standard values for the circuit parameters of the multi-module LCC high-voltage power supply, and the deviation of each module is based on the standard value. Usually, this standard value is the nominal value of each component. Based on the standard value, a state trajectory algorithm is established. First, calculate the initial startup period, and the state trajectory is as Figure 3 shown. The initial startup period can be calculated by the following formula:

[0030]

[0031]

[0032] where, I max0 is the maximum current peak that the H-bridge can output. Considering a certain margin, this value is taken as 75% of the maximum current value, and the normalized I maxN0 is the initial value of the trajectory calculation current. T0 is the conduction time of the switching tubes Q1 and Q4, and T1 is the conduction time of the switching tubes Q2 and Q3.

[0033] Calculate the initial startup period of each module LCC resonant converter according to the initial startup current value of each module LCC resonant converter.

[0034] S200, Sample the voltage values of each module LCC resonant converter and the total output voltage after the initial startup period ends. Among them, the voltage values include the input voltage value and the output voltage value. Calculate the trajectory startup current value of each module LCC resonant converter according to the input voltage value, output voltage value and total output voltage of each module LCC resonant converter.

[0035] In this embodiment, the calculation method of the trajectory startup current value is:

[0036] S201. After the sampling initial startup period ends, sample the input voltage value, output voltage value of each module LCC resonant converter, and the total output voltage of the multi-module LCC high-voltage power supply, and divide the total output voltage by the number of modules to obtain the average output voltage.

[0037] S202. After the error between the output voltage value of each module LCC resonant converter and the average output voltage is controlled by PI, obtain the startup current correction amount.

[0038] Exemplarily, input the error between the output voltage value of each module LCC resonant converter and the average output voltage into the PI controller to obtain the startup current correction amount.

[0039] S203. Add the startup current correction amount to the initial startup current value required by each module LCC resonant converter to obtain the trajectory startup current value of each module LCC resonant converter.

[0040] Calculate the trajectory startup current value in the fast startup stage, and the control logic of this stage is as Figure 4 shown. After sampling the output voltage of each module, according to the voltage unbalance degree, obtain the correction value of the per-unit value of the maximum current of the m-th module through PI control, and then the required trajectory startup current value I maxNm of the m-th module of the converter can be obtained. This trajectory startup current value is the maximum resonant current value required by each module. The trajectory diagram of this stage is as Figure 5 shown.

[0041] S300. According to the input voltage value, output voltage value, and trajectory startup current value of each module LCC resonant converter, calculate the switching period of each module and perform fast startup on each module until the output voltage value of each module LCC resonant converter reaches the set threshold value, and uniformly set the switching frequency of each module.

[0042] In this embodiment, the specific implementation method of step S300 is:

[0043] S301. According to the input voltage value and trajectory startup current value of each module LCC resonant converter, calculate the switching period of each module, that is, the switching frequency required for the next period of each module.

[0044] Based on the trajectory startup current value and the sampled input voltage value of each module, the switching period T sw can be obtained according to the following formula:

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] V AN = BV BN + C + 1

[0051] V CN = V BN + A + 1

[0052] ρ2 = 1 - V BN

[0053]

[0054]

[0055]

[0056] Wherein, I maxNm is the trajectory starting current value; V o is the output voltage of the LCC high-voltage resonant power supply; V in is the input voltage of the LCC resonant transformer; L r is the series resonant inductor of the LCC resonant transformer; C r is the series resonant capacitor of the LCC resonant transformer; C p is the value of the parallel resonant capacitor; Z0 is the characteristic impedance of the circular trajectory; Z1 is the characteristic impedance of the elliptical trajectory; ω0 is the characteristic angular frequency of the circular trajectory, ω1 is the characteristic angular frequency of the elliptical trajectory; A, B, C, V BN , V AN , V CN are intermediate quantities for calculation; ρ2, ρ3 are the radii of the circular trajectory; θ0, θ1, θ2 are the trajectory radian angles; T sw is the switching period.

[0057] S302. Use the obtained switching periods of each module to quickly start each module.

[0058] S303. Real-time collect the output voltage values of the LCC resonant converters of each module, and determine whether the output voltage values of the LCC resonant converters of each module reach the set threshold value.

[0059] Repeat steps S301 - 302, real-time sample the output voltage values of the LCC resonant converters of each module, and determine whether the output voltage values of the LCC resonant converters of each module reach the set threshold value. Exemplarily, the threshold value is 90% of the command voltage.

[0060] S304. If the output voltage value of each module's LCC resonant converter reaches the set threshold value, then close the switching period calculation, and change the operating frequency of each module's LCC resonant converter to the average value of the operating frequencies of each module in the previous switching period.

[0061] When the output voltage value of each module's LCC resonant converter reaches the set threshold value, then close the switching period calculation of each module above. Change the operating frequency of each module's LCC resonant converter to the same frequency f0, and this same frequency f0 is the average value of the operating frequencies of each module at the end of the previous order switching period.

[0062] The switching frequencies of each module calculated in step 301 are different. Therefore, by taking the average value method, unify the switching frequencies of each module so that each module can enter the inter-module phase shift link.

[0063] S400. Sample the output voltage of each module's LCC resonant converter, the total output voltage, and the phase difference of the resonant current between adjacent two modules. After subjecting the output voltage of each module's LCC resonant converter, the total output voltage, and the phase difference of the resonant current between adjacent two modules to PI voltage equalization control, PI frequency modulation control, and PI phase control, obtain the first phase shift angle, switching frequency, and second phase shift angle of each module to perform voltage stabilization, voltage equalization, and ripple cancellation for each module.

[0064] Please refer to Figure 2 , the specific implementation method for obtaining the switching frequency of each module after subjecting the total output voltage to PI frequency modulation control is:

[0065] Turn on the voltage stabilization loop, calculate the error between the total output voltage and the set command voltage, input this error into a PI (proportional integral) controller, perform PI frequency modulation control using the PI (proportional integral) controller, calculate the corresponding switching frequency of each module, and this switching frequency is the switching operating frequency of the H-bridge of each module's LCC resonant converter. Change the operating frequency of each module's LCC resonant converter to the same frequency to adjust the output voltage of the single-module LCC resonant converter and complete the voltage stabilization of the output voltage of each module's LCC resonant converter.

[0066] The present invention samples the total output voltage through the voltage stabilization loop, compares the total output voltage with the set command voltage, controls the output switching frequency through voltage stabilization PI, and adjusts the output voltage by adjusting the switching frequency of the entire power supply.

[0067] Please refer to Figure 2 , the specific implementation method for obtaining the first phase shift angle of each module after subjecting the output voltage of each module's LCC resonant converter to PI voltage equalization control is:

[0068] Turn on the voltage equalization loop;

[0069] Divide the total output voltage of each module LCC resonant converter by the number of modules to obtain the average output voltage;

[0070] Calculate the error between the output voltage of each module LCC resonant converter and the average output voltage, input the error into a PI (Proportional Integral) controller, perform PI voltage equalization control using the PI (Proportional Integral) controller, calculate the first phase shift angle of each module LCC resonant converter, and use this first phase shift angle as the phase shift angle between the front and rear bridge arms of the H-bridge of a single-module LCC resonant converter to adjust the output voltage of the single-module LCC resonant converter to achieve voltage equalization.

[0071] The present invention uses a voltage equalization ring to sample the output voltages of each module, compares them with the average value of the output voltages of each module, and controls the phase difference between the two half-bridges of the single-module H-bridge through voltage equalization PI control to adjust the output gain of the single-module, thereby controlling the output capacity of the single-module. For a module with an output value greater than the average value, the output voltage capacity is reduced through the phase difference, and vice versa, thus achieving voltage equalization of the output voltage.

[0072] Please refer to Figure 2 , the specific implementation method for obtaining the second phase shift angle of each module after PI phase control of the phase difference of the resonant current between adjacent two modules is as follows:

[0073] Turn on the phase control loop, calculate the error between the phase difference of the resonant current between adjacent two modules and the result of π divided by the number of modules, input the error into a PI (Proportional Integral) controller, perform PI phase control using the PI (Proportional Integral) controller, calculate the second phase shift angle of each module LCC resonant converter, and use this second phase shift angle as the phase shift angle between the H-bridges of different modules of the LCC resonant converter to cancel each other out and reduce the ripple of the output voltage of the LCC resonant converter.

[0074] The present invention samples the resonant current of each module through the inter-module phase difference control loop, and the phase difference between adjacent modules can be obtained through zero-crossing inversion, ensuring that the phase difference between each module is at the level of π divided by the number of modules, so that the output voltage ripple can be canceled to the greatest extent.

[0075] Under the control of these three control loops, namely the voltage stabilization loop, the voltage equalization loop, and the phase control loop, the process from 90% of the command value to 100% of the command value is completed. Among them, the control switch of the voltage stabilization loop should not be too large to avoid generating a large output voltage impact. The control bandwidth of the voltage equalization loop should be greater than the control bandwidth of the voltage stabilization loop.

[0076] After startup is completed, the three closed-loop controls keep functioning and achieve the steady-state control of the output voltage of the modular LCC. Until the console issues an end-output command, the control signals of the H-bridge are all 0, all switching tubes and PI controllers are turned off, and the output of the PI controller is cleared. The control process returns to the starting state and waits for the next command.

[0077] Due to the parameter differences in the circuits between different modules of the multi-module LCC high-voltage power supply, each module will have different gain capabilities, thus causing the voltage-sharing problem. Because of the load distribution effect, the circuit with a stronger gain capability will output more voltage, and the equivalent output resistance will be larger. And the lighter the equivalent load, the stronger the gain capability of the circuit, so an adverse positive feedback will be formed. This makes it difficult to apply the traditional single-module startup method to the startup of multi-modules. At the same time, during steady-state operation, different modules must work at the same frequency to ensure the feasibility of reducing ripple by phase-shifting between modules. Therefore, the fast startup method for the multi-module LCC high-voltage power supply proposed by the present invention utilizes the output voltage unevenness, as a characterization of different output capabilities between different modules. The voltage unevenness of each module is fed back into the calculation of the trajectory startup current value through PI control, changing the required trajectory startup current value for calculation, thereby adjusting its startup speed and achieving voltage sharing at the same time. During this process, the operating frequencies of each module during startup are not the same, but there is no requirement for output voltage ripple in the startup link itself, so there is no problem. Subsequently, when the output voltage reaches the threshold value, the above dynamic startup control mode is no longer used, and it switches to the steady-state control state. The initial operating frequency of each module becomes the average value of the previous operating frequencies, and at the same time, the three steady-state control loops start to work to complete the voltage regulation, voltage sharing, and ripple cancellation of the output voltage.

[0078] The fast startup method for the multi-module LCC high-voltage power supply proposed by the present invention realizes voltage sharing for each module LCC resonant converter during the fast startup process by performing PI voltage-sharing control on the output voltage of each module LCC resonant converter during the trajectory startup process.

[0079] The fast startup method for the multi-module LCC high-voltage power supply proposed by the present invention realizes a smooth switch to the steady-state control mode by setting the switching frequency of each module to the average value of the frequencies after the fast startup is completed.

[0080] The fast startup method for the multi-module LCC high-voltage power supply proposed by the present invention retains the fast startup advantage of the trajectory startup, enabling the converter to start quickly at a value near the maximum startup current. The method proposed by the present invention can achieve the fast startup of the multi-module LCC resonant converter, and realize voltage regulation, voltage sharing, and ripple cancellation during the fast startup.

[0081] The main advantage of the present invention compared with the prior art is that it takes into account both quick start-up and voltage equalization, enabling the multi-module LCC high-voltage power supply to have the ability to resist parameter deviation and solving the problem of quick start-up of the multi-module LCC high-voltage power supply.

[0082] The method for quickly starting up the multi-module LCC high-voltage power supply proposed by the present invention obtains the switching period for quick start-up through state trajectory control, ensuring that the power supply starts in the quick start-up mode. Through the voltage feedback method, the gain deviation between different modules is fed back, ensuring that each module can start at a relatively fast and the same speed, which not only guarantees the start-up speed but also avoids the problem of uneven voltage during the start-up process. After the start-up stage is completed, different modules switch to the average operating frequency point between modules, and at the same time, the voltage stabilization control loop, the voltage equalization control loop, and the phase control loop are turned on. Thereafter, the converters between different modules switch to the steady-state operating mode, achieving voltage equalization through the voltage equalization loop, reducing ripple through the phase control loop, and achieving voltage stabilization through the voltage stabilization control loop.

[0083] The above specific implementation manners do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fast startup method for a multi-module LCC high-voltage power supply, characterized in that, Including: Obtain the target gear and initial starting current value required for each module's LCC resonant converter, and calculate the initial starting period of each module's LCC resonant converter; Sample the input voltage value, output voltage value, and total output voltage of each module's LCC resonant converter after the end of the initial starting period. According to the input voltage value, output voltage value, and total output voltage of each module's LCC resonant converter, calculate the trajectory starting current value of each module's LCC resonant converter; According to the input voltage value, output voltage value, and trajectory starting current value of each module's LCC resonant converter, calculate the switching period of each module and perform rapid startup for each module until the output voltage value of each module's LCC resonant converter reaches the set threshold value, and uniformly set the switching frequency of each module; Sample the output voltage, total output voltage, and phase difference of the resonant current between adjacent two modules of each module's LCC resonant converter. After subjecting the output voltage, total output voltage, and phase difference of the resonant current between adjacent two modules of each module's LCC resonant converter to PI voltage equalization control, PI frequency modulation control, and PI phase control, obtain the steady-state control value of each module to perform voltage stabilization, voltage equalization, and ripple cancellation for each module; The calculation method of the trajectory starting current value of each module's LCC resonant converter is as follows: Sample the output voltage value and total output voltage of each module's LCC resonant converter after the end of the initial starting period, and divide the total output voltage by the number of modules to obtain the average output voltage; After subjecting the error between the output voltage value of each module's LCC resonant converter and the average output voltage to PI control, obtain the starting current correction amount; Add the starting current correction amount to the initial starting current value required for each module's LCC resonant converter to obtain the trajectory starting current value of each module's LCC resonant converter.

2. The fast startup method of the multi-module LCC high-voltage power supply according to claim 1, characterized in that, The step of calculating the switching period of each module according to the input voltage value, output voltage value, and trajectory starting current value of each module's LCC resonant converter and performing rapid startup for each module until the output voltage value of each module's LCC resonant converter reaches the set threshold value includes: According to the input voltage value and trajectory starting current value of each module's LCC resonant converter, calculate the switching period of each module and perform rapid startup for each module; Real-time collect the output voltage value of each module's LCC resonant converter, and judge whether the output voltage value of each module's LCC resonant converter reaches the set threshold value; If the output voltage value of each module's LCC resonant converter reaches the set threshold value, close the switching period calculation, and set the operating frequency of each module's LCC resonant converter to the same frequency.

3. The fast start-up method of the multi-module LCC high-voltage power supply according to claim 2, characterized in that, The calculation method of the switching period of each module is as follows: V AN = BV BN + C + 1 V CN = V BN + A + 1 ρ2 = 1 - V BN Among them, I maxNm is the trajectory starting current value; V om is the output voltage of a single module of the LCC high-voltage resonant power supply; V in is the input voltage of the LCC resonant transformer; L r is the series resonant inductor of the LCC resonant transformer; C r is the series resonant capacitor of the LCC resonant transformer; C p is the parallel resonant capacitance value; Z0 is the characteristic impedance of the circular trajectory; Z1 is the characteristic impedance of the elliptical trajectory; ω0 is the characteristic angular frequency of the circular trajectory, and ω1 is the characteristic angular frequency of the elliptical trajectory; A, B, C, V BN , V AN , V CN are intermediate quantities for calculation; ρ2 and ρ3 are the radii of the circular trajectory; θ0, θ1, and θ2 are the radian angles of the trajectory; T sw is the switching period.

4. The rapid start-up method of the multi-module LCC high-voltage power supply according to claim 2, characterized in that The same frequency is the average value of the operating frequencies of each module in the previous switching period.

5. The fast startup method of the multi-module LCC high-voltage power supply according to claim 1, characterized in that The steady-state control value includes the switching frequency. The step of obtaining the switching frequency of each module after subjecting the total output voltage to PI frequency modulation control includes: Calculate the error between the total output voltage and the set command voltage, and after subjecting this error to PI frequency modulation control, obtain the corresponding switching frequency of each module to perform voltage stabilization for each module.

6. The rapid start-up method of the multi-module LCC high-voltage power supply according to claim 1, characterized in that The steady-state control value includes a first phase-shift angle. The steps of obtaining the first phase-shift angle of each module after PI voltage equalization control of the output voltages of each module's LCC resonant converter are as follows: Calculate the error between the output voltage of each module's LCC resonant converter and the average output voltage obtained by dividing the total output voltage by the number of modules; after subjecting this error to PI voltage equalization control, calculate the first phase-shift angle of each module's LCC resonant converter to equalize the voltages of each module.

7. The fast startup method of the multi-module LCC high-voltage power supply according to claim 1, wherein The steady-state control value includes a second phase-shift angle. The steps of obtaining the second phase-shift angle of each module after PI phase control of the phase difference between the resonant currents of adjacent two modules are as follows: Calculate the error between the phase difference between the resonant currents of adjacent two modules and the result of dividing π by the number of modules, and after subjecting this error to PI phase control, obtain the second phase-shift angle of each module to cancel the ripples of each module.

8. The fast startup method of the multi-module LCC high-voltage power supply according to claim 1, wherein The multi-module LCC high-voltage power supply is composed of multiple single-module high-voltage power supplies, and the inputs of each single module are connected in parallel and the outputs are connected in series.

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