A battery-powered pulse-capacitor charging power supply and a control method thereof

Abstract

The application discloses a battery-powered pulse capacitor charging power supply. The main circuit adopts a two-stage boost structure, the front stage is an interleaved parallel double Boost converter, and the rear stage adopts an LCC resonant converter. The interleaved parallel double Boost converter can realize a relatively high boost ratio and reduce output voltage ripple; the LCC resonant converter can fully utilize the parasitic parameters of a transformer, realize soft switching of a switching tube, charge a load capacitor in the form of a small pulse, and realize relatively high charging precision. The application first proposes a two-stage pulse capacitor charging power supply structure composed of an interleaved parallel double Boost converter and an LCC resonant converter. The front stage realizes stable boost through voltage and current double closed loop control, and the response speed is improved. The rear stage realizes full-range soft switching and constant current charging through critical discontinuous constant current control, and the charging speed, charging efficiency and charging linearity are improved, and the charging performance of the pulse capacitor charging power supply is improved.

Description

Technical Field

[0001] This invention belongs to the field of power electronic converters, and specifically relates to a battery-powered pulse capacitor charging power supply and its control method. Background Technology

[0002] Traditional DC power supplies typically provide stable and efficient DC voltage or current to fixed loads, operating in a steady state most of the time. However, in some applications, such as high-power lasers, particle accelerators, radar, and electromagnetic generators, systems require repeatable, high-density, high-power energy output for short periods, known as high-energy pulse systems. This energy is generally stored in pulse capacitors and then released within a short time. The quality of the pulse capacitor charging power supply determines whether the pulse capacitor can be stably charged to its rated voltage within the rated time and maintained until discharge.

[0003] High-frequency converters, with their higher switching frequencies, can reduce the size of magnetic components in the circuit, increase the power density of the charging power supply, and lower the design cost. Furthermore, they charge capacitors using small pulses, resulting in a slow rise in output voltage and high charging accuracy. Therefore, high-frequency converters are widely used in capacitor charging power supplies. An ideal LC series resonant converter operates with a constant output current in discontinuous current mode, achieving constant current charging. However, due to the parasitic parameters of the high-frequency high-voltage transformer, an LC series resonant converter is essentially an LCC series-parallel resonant converter. Currently, the mainstream control method for LCC resonant converters operating in discontinuous current mode is fixed-frequency control. This is not only simple to control but also enables zero-current soft switching across the entire range, improving circuit efficiency and reliability. However, in fixed-frequency controlled LCC resonant converters, the current decays rapidly as the charging voltage increases, severely affecting the charging speed and linearity.

[0004] Most pulse capacitor charging power supplies use rectified three-phase AC power for power. However, in some low-voltage power supply applications, such as electromagnetic weapons and mobile laser weapons, batteries or supercapacitors are required as primary energy storage to power the system. In these cases, the power supply needs to be able to boost the voltage from tens of volts to thousands or even tens of thousands of volts. If a single-stage voltage boosting structure is used directly, it will result in too many turns in the transformer coil, a large size, reduced efficiency, and, due to the large current at the low-voltage end and the rapid current change, it will cause significant electromagnetic interference. Summary of the Invention

[0005] The purpose of this invention is to propose a battery-powered pulse capacitor charging power supply and its control method to improve the performance of the pulse capacitor charging power supply. By adopting critical discontinuous constant current control, the charging efficiency is improved while the charging speed and charging linearity are also improved. For battery-powered applications, a two-stage boost structure is used, with an interleaved parallel dual boost converter added before the LCC resonant converter, which reduces the transformer size, improves charging efficiency, and reduces electromagnetic interference.

[0006] The technical solution for achieving this invention is: a battery-powered pulse capacitor charging power supply, implemented through interleaved parallel dual Boost converters, voltage and current dual closed-loop control, an LCC resonant converter, and critical discontinuous constant current control. Wherein:

[0007] The interleaved parallel dual Boost converter is a front-stage boost circuit consisting of two Boost converters connected in parallel, with 180° phase shift control in the upper and lower branches, used to boost the input voltage level of the subsequent LCC resonant converter.

[0008] The voltage and current dual closed-loop control is the control method for the front-stage interleaved parallel dual Boost converter, which is used to stabilize the front-stage output voltage and achieve branch current balance.

[0009] The LCC resonant converter is the subsequent boost circuit, consisting of a full-bridge inverter circuit, an LCC resonant cavity, a transformer, and a full-bridge rectifier circuit, used to charge the pulse capacitor.

[0010] Critical discontinuous constant current control is the control method for the subsequent LCC resonant converter, used to improve the performance of the pulse capacitor charging power supply.

[0011] The control method for a battery-powered pulse capacitor charging power supply proposed in this invention comprises the following steps:

[0012] Step 1: Interleaved parallel dual Boost converters are used to boost the voltage level, forming the front-end boost circuit. The working principle of a single branch is: when the switching transistor Q... i When the circuit is on, the input power supply V in Boost inductor L i Charging, output capacitor C i Maintain a constant output voltage; when the switching transistor Q i When turned off, the input power supply V in and boost inductor L i Simultaneously supplying power to the load. The upper and lower branches employ 180° phase-shift control, specifically the second switching transistor Q. i2 The drive signal lags behind the first switching transistor Q. i1 A 180° drive signal can reduce output voltage ripple.

[0013] Step 2: The voltage and current dual closed-loop control is a control method for the front-end interleaved parallel dual Boost converter. The outer voltage loop stabilizes the output voltage, while the inner current loop improves the response speed and achieves branch current balance. The output voltage is sampled and compared with the voltage reference value. The error is sent to the PI controller to calculate the current reference value. Then, the difference between the current reference value and the sampled inductor current value is calculated, and the result is sent to the PI controller, and then output as Q by the PWM module. i1 The drive signal, and simultaneously Q i1 The drive signal is delayed by half a cycle as Q i2 The driving signals are used to achieve interleaved parallel connection.

[0014] Step 3: The output voltage of the front-stage interleaved parallel dual Boost converter is used as the input voltage of the subsequent LCC resonant converter, which charges the load capacitor. When the first switch Q1 and the fourth switch Q4 are turned on, the input power first passes through the first switch Q1, the fourth switch Q4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the primary side via the first diode V. o1 and the fourth diode V o4 To the load capacitor C o Charging begins; then, when the resonant current reaches zero and begins to reverse, the input power supply passes through the first switch transistor anti-parallel diode VD1, the fourth switch transistor anti-parallel diode VD4, and the series resonant inductor L. r Series resonant capacitor C s To the parallel resonant capacitor C p Reverse charging; when the parallel resonant capacitor C p When the voltage reaches the clamping voltage, the input power supply passes through the first switch transistor anti-parallel diode VD1, the fourth switch transistor anti-parallel diode VD4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the secondary side via the second diode V. o2 and the third diode V o3 To the load capacitor C o Charging is performed. The same situation occurs when the second switch Q2 and the third switch Q3 are turned on.

[0015] Step 4: Critical discontinuous constant current control is the control method for the subsequent LCC resonant converter. The output capacitor voltage is acquired by a voltage sampling circuit and sent to the ADC module of the digital processing chip (DSP). Simultaneously, the event trigger (ET) submodule in the ePWM module generates an ADC start signal. Each start trigger performs an ADC sampling, and data processing is performed in the interrupt to calculate the critical discontinuous frequency. Considering the complexity of calculating the critical discontinuous frequency and the processing speed of the DSP, the expression for the critical discontinuous frequency is pre-linearized piecewise. Then, in the interrupt program, the acquired output voltage is judged, and the critical discontinuous frequency is calculated as the upper limit of the PI regulation frequency for the average output current closed-loop control. The output current is converted into a resistor voltage through a sampling resistor, and then passes through an LC filter circuit. The voltage of the filtered capacitor is then the average output current. The voltage sampling circuit acquires the filtered capacitor voltage as the average output current and sends it to the DSP's ADC module. Incremental PI regulation is performed in the interrupt to achieve constant current output. The reference current is the minimum output current during charging when critical discontinuous control is used.

[0016] Compared with existing pulse capacitor charging power supply technology, this invention has significant advantages: Firstly, it adopts a two-stage boost structure. Adding a boost structure before the LCC resonant converter can increase the input bus voltage, reduce the transformer turns ratio, thereby reducing the transformer size and improving efficiency. Furthermore, the front-stage interleaved parallel Boost converter has the characteristics of input shunt and output series boost, suitable for the low-voltage, high-current characteristics of the front stage. Simultaneously, the use of 180° phase-shift control in the upper and lower branches can reduce output voltage ripple. Secondly, for the subsequent LCC resonant converter, critical discontinuous constant current control is adopted. By acquiring the output voltage and calculating the critical discontinuous frequency in real time, it serves as the upper limit of the PI regulation frequency for the average output current closed-loop control. Simultaneously, the minimum output current during charging under critical discontinuous control is used as the current reference value. This ensures the circuit operates in discontinuous mode, achieving full-range ZCS soft switching, improving charging efficiency while also enhancing charging speed and linearity. Attached Figure Description

[0017] Figure 1 This is a topology diagram of a two-stage pulse capacitor charging power supply.

[0018] Figure 2 This is the control block diagram of a front-end interleaved parallel dual Boost converter using voltage and current dual closed-loop control.

[0019] Figure 3 This is the control block diagram of the subsequent LCC resonant converter when critical discontinuous constant current control is used.

[0020] Figure 4 The output voltage and inductor current waveforms of the interleaved parallel dual Boost converter are shown when using dual closed-loop voltage and current control.

[0021] Figure 5 These are the output voltage and average output current waveforms of the LCC resonant converter when using fixed-frequency control and critical discontinuous control, respectively.

[0022] Figure 6 This is a waveform diagram of the resonant current of the LCC resonant converter at different output voltage stages when using fixed frequency control.

[0023] Figure 7 This is a waveform diagram of the resonant current of the LCC resonant converter at different output voltage stages when critical discontinuous control is used.

[0024] Figure 8 The waveforms of the output voltage and average output current of the LCC resonant converter when critical discontinuous constant current control is used are shown.

[0025] Figure 9 This is a waveform diagram of the output voltage of the two stages when a two-stage structure is used. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0027] like Figure 1 , Figure 2 and Figure 3 As shown, a battery-powered pulse capacitor charging power supply structure and control scheme design employs an interleaved parallel dual-Boost converter, voltage and current dual closed-loop control, an LCC resonant converter, and critical discontinuous constant current control. Specifically: the interleaved parallel dual-Boost converter is the front-stage boost circuit used to increase the input voltage level of the subsequent LCC resonant converter. The voltage and current dual closed-loop control is the control method for the front-stage interleaved parallel dual-Boost converter, used to stabilize the front-stage output voltage and achieve branch current balancing. The LCC resonant converter is the subsequent boost circuit used to charge the pulse capacitor. Critical discontinuous constant current control is the control method for the subsequent LCC resonant converter, used to improve the performance of the pulse capacitor charging power supply.

[0028] The interleaved parallel dual-Boost converter, as shown in Figure 2 As shown, this is composed of two Boost converters connected in parallel. A Boost converter mainly consists of an inductor, a switching transistor, a diode, and a capacitor. Inductor L... i The function of the inductor is energy storage. During the conduction period of the switching transistor, the inductor stores energy. When the switching transistor is turned off, the inductor current cannot change abruptly, generating a back electromotive force (EMF). This EMF is superimposed on the power supply voltage, making the output voltage higher than the input voltage. Switch Q i Its function is to control the output voltage by adjusting the switching transistor Q. i The conduction time of the diode changes the output voltage. iIts function is isolation; when the switching transistor is on, the diode is reverse-biased and cut off, so the energy storage process of the inductor will not affect the power supply from the output capacitor to the load. Capacitor C i Its function is to store energy and maintain a constant output voltage. The 180° phase shift control of the upper and lower branches of the interleaved parallel dual Boost converter can reduce the output voltage ripple and mainly plays the role of increasing the input voltage level of the subsequent LCC resonant converter.

[0029] The voltage and current dual closed-loop control, such as Figure 2 The diagram illustrates the control scheme of a front-end interleaved parallel dual-Boost converter, primarily composed of an outer voltage loop and an inner current loop. The outer voltage loop stabilizes the output voltage, while the inner current loop enhances response speed. Compared to single-loop voltage control, the addition of current control immediately causes changes in the inductor current due to fluctuations in either the input voltage or the load. This changes the current feedback signal, prompting the control system to react and adjust immediately, unlike single-loop voltage control which waits for a change in the output voltage. This improves the transient characteristics of the control system and also achieves branch current balancing.

[0030] The LCC resonant converter, such as Figure 3 The diagram shows the boost converter circuit, which mainly consists of a full-bridge inverter circuit, an LCC resonant cavity, a transformer, and a full-bridge rectifier circuit. The full-bridge inverter circuit is... Figure 3 The switching circuit, composed of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4, mainly converts the input DC power into AC power. The LCC resonant cavity consists of... Figure 3 The series resonant inductor L r Series resonant capacitor C s and parallel resonant capacitor C p The structure consists of an inductor whose current resonates to zero before the switching transistors Q1-Q4 are turned off, achieving zero-current turn-off (ZCS) for the switching transistors. A transformer, such as... Figure 3 As shown in the ideal transformer diagram, its parasitic parameters, namely leakage inductance and distributed capacitance, are equivalent to the series resonant inductance L. r and parallel resonant capacitor C p In a transformer, the main functions are energy transmission and isolation. A full-bridge rectifier circuit, such as... Figure 3 As shown, the first diode VD o1 Second diode VD o2 Third diode VD o3 and the fourth diode VD o4 It is composed of components and its main function is to convert alternating current into direct current.

[0031] The critical discontinuous constant current control, such as Figure 3The diagram illustrates the control method for the subsequent LCC resonant converter, primarily composed of critical discontinuous control and a PI-based algorithm-based current closed-loop control. Critical discontinuous control uses real-time acquisition of the output voltage to calculate the critical discontinuity frequency, which is then used as the actual switching frequency to control the switching transistors of the full-bridge inverter circuit. At this point, the current output capability is the maximum current output capability of the LCC resonant converter in discontinuous mode, improving energy utilization and thus increasing charging speed. The PI-based algorithm-based current closed-loop control compares the average output current with a reference value, then uses a PI modulator and comparator to output a drive signal to control the switching transistors of the full-bridge inverter circuit, achieving current stability and improving charging linearity. Critical discontinuous constant current control uses the calculated critical discontinuity frequency as the upper frequency limit for the current closed-loop control, achieving both good charging speed and charging linearity.

[0032] The control method for the battery-powered pulse capacitor charging power supply includes the following specific steps:

[0033] Step 1: Interleaved parallel dual Boost converters are used to boost the voltage level, forming the front-end boost circuit. The working principle of a single branch is: when the switching transistor Q... i When on, the input power supply V in Boost inductor L i Charging, output capacitor C i Maintain a constant output voltage; when the switching transistor Q i When turned off, the input power supply V in and boost inductor L i Simultaneously supplying power to the load. The upper and lower branches employ 180° phase-shift control, specifically the second switching transistor Q. i2 The drive signal lags behind the first switching transistor Q. i1 A 180° drive signal can reduce output voltage ripple.

[0034] Step 2: The voltage and current dual closed-loop control is a control method for the front-end interleaved parallel dual Boost converter. The outer voltage loop stabilizes the output voltage, while the inner current loop improves the response speed and achieves branch current balance. The output voltage is sampled and compared with the voltage reference value. The error is sent to the PI controller to calculate the current reference value. Then, the difference between the current reference value and the sampled inductor current value is calculated, and the result is sent to the PI controller, and then output as Q by the PWM module. i1 The drive signal, and simultaneously Q i1 The drive signal is delayed by half a cycle as Q i2 The driving signals are used to achieve interleaved parallel connection.

[0035] Step 3: The output voltage of the front-stage interleaved parallel dual Boost converter is used as the input voltage of the subsequent LCC resonant converter, which charges the load capacitor. When the first switch Q1 and the fourth switch Q4 are turned on, the input power first passes through the first switch Q1, the fourth switch Q4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the primary side via the first diode V. o1 and the fourth diode V o4 To the load capacitor C o Charging begins; then, when the resonant current reaches zero and begins to reverse, the input power supply passes through the first switch transistor anti-parallel diode VD1, the fourth switch transistor anti-parallel diode VD4, and the series resonant inductor L. r Series resonant capacitor C s To the parallel resonant capacitor C p Reverse charging; when the parallel resonant capacitor C p When the voltage reaches the clamping voltage, the input power supply passes through the first switch transistor anti-parallel diode VD1, the fourth switch transistor anti-parallel diode VD4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the secondary side via the second diode V. o2 and the third diode V o3 To the load capacitor C o Charging is performed. The same situation occurs when the second switch Q2 and the third switch Q3 are turned on.

[0036] Step 4: Critical discontinuous constant current control is the control method for the subsequent LCC resonant converter. The output capacitor voltage is acquired by a voltage sampling circuit and sent to the ADC module of the digital processing chip (DSP). Simultaneously, the event trigger (ET) submodule in the ePWM module generates an ADC start signal. Each start trigger performs an ADC sampling, and data processing is performed in the interrupt to calculate the critical discontinuous frequency. Considering the complexity of calculating the critical discontinuous frequency and the processing speed of the DSP, the expression for the critical discontinuous frequency is pre-linearized piecewise. Then, in the interrupt program, the acquired output voltage is judged, and the critical discontinuous frequency is calculated as the upper limit of the PI regulation frequency for the average output current closed-loop control. The output current is converted into a resistor voltage through a sampling resistor, and then passes through an LC filter circuit. The voltage of the filtered capacitor is then the average output current. The voltage sampling circuit acquires the filtered capacitor voltage as the average output current and sends it to the DSP's ADC module. Incremental PI regulation is performed in the interrupt to achieve constant current output. The reference current is the minimum output current during charging when critical discontinuous control is used.

[0037] The working principle is analyzed as follows:

[0038] The front-stage interleaved parallel dual boost converter acts as a voltage booster, increasing the input bus voltage of the subsequent LCC resonant converter, reducing the transformer step-up ratio, thereby reducing transformer size, improving efficiency, and reducing electromagnetic interference. Simultaneously, 180° phase-shift control is used in both the upper and lower branches to reduce output voltage ripple. While single-loop voltage control is simple and easy to design, the system only responds when the output voltage changes, resulting in slow response and potential for large voltage fluctuations or even system instability during regulation. Therefore, an inner voltage loop is added to the voltage control system, with the outer voltage loop forming a dual voltage-current closed-loop control. In power supply regulation systems with current control, fluctuations in either the input voltage or the load immediately cause changes in the inductor current, altering the current feedback signal and prompting the control system to react and adjust. Therefore, dual-loop control offers fast dynamic response, good regulation performance, and minimal output voltage overshoot. Furthermore, dual-loop control enables current balancing in each branch. Figure 4 The output voltage and inductor current waveforms of the interleaved parallel dual Boost converter with voltage and current dual closed-loop control are obtained using PLECS simulation.

[0039] Improving the performance of a charging power supply requires deriving the output characteristics of an LCC resonant converter, specifically the expression for the average output current. Because the resonant current waveform of an LCC resonant converter deviates significantly from a sine wave and the switching frequency is far from the resonant frequency when operating in discontinuous mode, the fundamental frequency approximation method will result in substantial errors. Furthermore, the time-domain equation method is not only computationally complex but also only yields numerical solutions. Therefore, the state-plane analysis method is typically used. By plotting state trajectory diagrams and combining geometric relationships, the expression for the average output current is derived. This is well-known to those skilled in the art and will not be elaborated upon here. The normalized average output current I... o_norm The expression is:

[0040]

[0041] Among them, the equivalent voltage gain G o =V o / nV in Initial resonant frequency k is the ratio of parallel to series capacitors, V in V o These are the input voltage and output voltage, respectively, where n is the transformer turns ratio, and L... r C is the inductance value of the series resonant inductor. s This is the capacitance value of the series resonant capacitor.

[0042] When the circuit parameters are determined, the series capacitance ratio k and the initial resonant frequency f are... rIt is also determined that the switching frequency is a key factor affecting the change in average output current. Traditional solutions employ fixed-frequency control to ensure the circuit operates in discontinuous mode, achieving full-range ZCS and improving charging efficiency, thus maintaining the switching frequency at half the initial resonant frequency. However, as the charging voltage increases, the current decays rapidly, severely impacting charging speed and linearity. Therefore, this invention employs critical discontinuous control, calculating the critical discontinuous frequency in real-time by acquiring the output voltage as the actual switching frequency. The output current at this point represents the maximum current output capability of the LCC resonant converter in discontinuous mode. The normalized critical discontinuous frequency f... scri The expression is:

[0043]

[0044] Among them, the LC series resonant angular frequency LCC series-parallel resonant angular frequency Series equivalent capacitance C m =C s C p / (C s +C p Equivalent output voltage V e =V o / n, initial value of parallel resonant capacitor voltage C p This is the capacitance value of the parallel resonant capacitor.

[0045] Using PLECS software, LCC resonant converters employing traditional fixed-frequency control and critical discontinuous control were simulated respectively, and their output voltage and average output current waveforms were obtained as follows: Figure 5 As shown, the critical discontinuous control scheme improves the current output capability and accelerates the charging speed compared to the traditional fixed-frequency control scheme. The resonant current waveforms corresponding to different output voltage stages are shown below. Figure 6 and Figure 7 As shown, when critical discontinuous control is adopted, the stage of resonant current discontinuity is eliminated by making the switching frequency track the critical discontinuous switching frequency in real time, thus realizing the critical discontinuity of resonant current throughout the entire charging process.

[0046] The critical discontinuous constant current control consists of critical discontinuous control and current closed-loop control based on a PI algorithm. The calculated critical discontinuous frequency is used as the upper limit of the current closed-loop control frequency, which can achieve good charging speed and charging linearity. Figure 8 The output voltage and average output current waveforms are shown when critical discontinuous constant current control is used.

[0047] The output voltages of the two stages were obtained by simulating the two-stage system using PLECS software. Figure 9As shown, the front-end interleaved parallel dual boost converter has a fast response speed due to the use of voltage and current dual closed-loop control, and the output voltage quickly reaches 100V. The subsequent LCC resonant converter has a further improved charging speed due to the boost voltage of the front stage.

Claims

1. A battery-powered pulse capacitor charging power supply, characterized in that: This is achieved through interleaved parallel dual-Boost converters, dual closed-loop voltage and current control, an LCC resonant converter, and critical discontinuous constant current control, wherein: The interleaved parallel dual Boost converter, used as the front-stage boost circuit, consists of two Boost converters connected in parallel. The upper and lower branches are controlled by 180° phase shift, which can reduce the output voltage ripple and improve the input voltage level of the subsequent LCC resonant converter. As the control method for the front-end interleaved parallel dual Boost converter, the voltage outer loop can stabilize the output voltage, and the current inner loop can improve the response speed. The dual-loop control has fast dynamic response, good regulation performance, small overshoot of output voltage regulation, and can also achieve branch current balance. The output voltage is compared with a voltage reference value, and the error is sent to the voltage PI controller to calculate the current reference value. Then, the difference between the current reference value and the sampled inductor current value is calculated, and the result is sent to the current PI controller, and then output to the PWM module via the switching transistor Q. i1 and the switching transistor Q i2 The drive signal simultaneously switches the transistor Q. i1 The drive signal is delayed by half a cycle as the switching transistor Q. i2 The driving signals are used to achieve interleaved parallel connection; The LCC resonant converter, as the subsequent boost circuit, includes a full-bridge inverter circuit, an LCC resonant cavity, a transformer, and a full-bridge rectifier circuit. The leakage inductance and parasitic capacitance of the transformer are respectively referred to the series resonant inductance and parallel resonant capacitance of the primary side of the transformer. The output characteristics of the LCC resonant converter are controlled by adjusting the drive signals of the four switching transistors in the full-bridge inverter circuit. Critical discontinuous constant current control is used as the control method for the subsequent LCC resonant converter. When the LCC resonant converter operates in discontinuous mode, it can achieve full-range ZCS soft switching, improving the energy transfer efficiency and reliability of the circuit. The current output capability corresponding to the LCC resonant converter operating in critical discontinuous mode is the maximum current output capability of the LCC resonant converter in discontinuous mode. Therefore, critical discontinuous control is adopted, that is, the output voltage is collected in real time and the critical discontinuity frequency is calculated to control the switching transistors of the full-bridge inverter circuit. This can improve energy utilization and thus improve charging speed. At the same time, in order to achieve constant current charging, average output current closed-loop control is required. Finally, critical discontinuous constant current control is adopted to improve charging speed and charging linearity.

2. The battery-powered pulse capacitor charging power supply according to claim 1, characterized in that: The interleaved parallel dual-boost converter consists of two boost converters connected in parallel, wherein each boost converter includes a boost inductor L. i diode VD i and output capacitor C i By controlling the switching transistor Q i1 and switching transistor Q i2 The output voltage can be regulated by 180° phase shift control of the upper and lower branches, which can reduce the output voltage ripple.

3. The battery-powered pulse capacitor charging power supply according to claim 2, characterized in that: The voltage and current dual closed-loop control consists of an outer voltage loop and an inner current loop. The outer voltage loop stabilizes the output voltage of the interleaved parallel dual Boost converters, while the inner current loop improves the system's response speed and achieves branch current balance.

4. The battery-powered pulse capacitor charging power supply according to claim 3, characterized in that: The LCC resonant converter includes a full-bridge inverter circuit, an LCC resonant cavity, a transformer, and a full-bridge rectifier circuit, wherein the LCC resonant cavity includes a series resonant inductor L. r Series resonant capacitor C s and parallel resonant capacitor C p The output voltage and current are adjusted by controlling the switching transistors Q1 to Q4.

5. The battery-powered pulse capacitor charging power supply according to claim 4, characterized in that: The critical discontinuous constant current control consists of critical discontinuous control and average output current closed-loop control. When the LCC resonant converter operates in discontinuous mode, it can achieve full-range ZCS soft switching, improving the energy transfer efficiency and reliability of the circuit. The current output capability corresponding to the LCC resonant converter operating in critical discontinuous mode is the maximum current output capability of the LCC resonant converter in discontinuous mode. Therefore, keeping the circuit in critical discontinuous mode can improve energy conversion efficiency and charging speed. Critical discontinuous control is achieved by real-time acquisition of the output voltage and calculation of the critical discontinuous frequency as the switching frequency of the switching transistors Q1 to Q4, so that the LCC resonant converter always operates in critical discontinuous mode. At the same time, in order to improve charging linearity and make the capacitor voltage rise linearly, average output current closed-loop control is added, using a PI control algorithm for frequency adjustment. Critical discontinuous constant current control combines critical discontinuous control and average output current closed-loop control, using the calculated critical discontinuous switching frequency as the upper limit of PI frequency adjustment, thereby improving the charging speed and charging linearity of the pulse capacitor charging power supply.

6. A control method for a battery-powered pulse capacitor charging power supply as described in any one of claims 1 to 5, characterized in that, The steps are as follows: Step 1: Interleaved parallel dual Boost converters are used to increase the voltage level, forming the front-end boost circuit; the working principle of a single branch is: when the switching transistor Q... i1 and the switching transistor Q i2 When on, the input power supply V in Boost inductor L i Charging, output capacitor C i Maintain a constant output voltage; When the switching transistor Q i1 and the switching transistor Q i2 When turned off, the input power supply V in and boost inductor L i Simultaneously supplying power to the load; the upper and lower branches employ 180° phase shift control, i.e., the switching transistor Q... i2 The drive signal lags behind the switching transistor Q i1 The drive signal is 180° to reduce output voltage ripple; Step 2: The voltage and current dual closed-loop control is a control method for the front-end interleaved parallel dual Boost converter. The outer voltage loop stabilizes the output voltage, while the inner current loop improves the response speed and achieves branch current balance. The output voltage is sampled and compared with the voltage reference value. The error is sent to the voltage PI controller to calculate the current reference value. Then, the difference between the current reference value and the sampled inductor current value is calculated, and the result is sent to the current PI controller. Finally, the output switching transistor Q is generated by the PWM module. i1 The drive signal simultaneously switches the transistor Q. i1 The drive signal is delayed by half a cycle as the switching transistor Q. i2 The driving signals are used to achieve interleaved parallel connection; Step 3: The output voltage of the front-stage interleaved parallel dual Boost converter is used as the input voltage of the subsequent LCC resonant converter, which charges the load capacitor. When switches Q1 and Q4 are turned on, the input power first passes through switches Q1 and Q4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the primary side via the first diode VD. o1 and the fourth diode VD o4 To the load capacitor C o Charging begins; then, when the resonant current reaches zero and begins to reverse, the input power supply passes through the anti-parallel diode VD1 of switch Q1, the anti-parallel diode VD4 of switch Q4, and the series resonant inductor L. r Series resonant capacitor C s To the parallel resonant capacitor C p Reverse charging; When the parallel resonant capacitor C p When the voltage reaches the clamping voltage, the input power supply passes through the anti-parallel diode VD1 of switch Q1, the anti-parallel diode VD4 of switch Q4, and the series resonant inductor L. r Series resonant capacitor C s Energy is transferred from the primary side of the transformer to the secondary side, and the energy is transferred from the secondary side to the secondary side via the second diode VD. o2 and the third diode VD o3 To the load capacitor C o Charging is performed; the same situation occurs when switching transistors Q2 and Q3 are turned on. Step 4: Critical discontinuous constant current control is the control method for the subsequent LCC resonant converter. The output capacitor voltage is collected by the voltage sampling circuit and sent to the DSP's ADC module. At the same time, the ET submodule in the ePWM module generates an ADC start signal. Each start-up performs an ADC sampling, and then data processing is performed in the interrupt to calculate the critical discontinuous frequency. Considering the complexity of the critical discontinuous frequency calculation and the processing speed of the DSP, the expression of the critical discontinuous frequency is piecewise linearized beforehand. Then, the collected output voltage is judged in the interrupt program, and the critical discontinuous frequency is calculated as the upper limit of the PI adjustment frequency for the average output current closed-loop control. The output current is converted into resistor voltage through the sampling resistor, and then passes through the LC filter circuit. At this time, the capacitor voltage of the LC filter circuit is the average output current. The voltage sampling circuit collects the filtered capacitor voltage as the average output current and sends it to the DSP's ADC module. Incremental PI adjustment is performed in the interrupt to achieve constant current output. The reference current is the minimum output current during charging when using critical discontinuous control.

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