Switched-capacitor converters and their surge current suppression methods

Abstract

This application provides a switched-capacitor converter and its surge current suppression method. The switched-capacitor converter includes a controller, a first capacitor, n resonant cavities, and n second capacitors connected in series. The first capacitor is connected in series with the n second capacitors, and one of the n resonant cavities is connected across the first capacitor and one of the n second capacitors. The controller is used to control the switching of each resonant cavity based on the drive signal of each resonant cavity when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are off, so as to suppress surge current. The drive signal of any resonant cavity is obtained based on the switching frequency and duty cycle of the corresponding target switch. As the number of times the target switch is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity, and the duty cycle increases from the initial duty cycle to a preset duty cycle. Implementing this application does not require adding a current limiting circuit; surge current can be suppressed through software control strategies.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a switched capacitor converter and its surge current suppression method. Background Technology

[0002] A switched-capacitor converter (SCC) is a voltage converter that relies on capacitors to achieve energy transfer and voltage transformation. A typical SCC includes multiple capacitors, switching devices, and inductors. The inductor can resonate with the capacitors, providing the conditions for soft switching of the switching devices. In steady-state operation, the voltage across the capacitor is a DC voltage plus the ripple voltage generated by the capacitor's charging and discharging. During startup, the voltage across the capacitor is usually zero, so it needs to be gradually charged to the steady-state voltage. However, during startup, the peak current flowing through the SCC can be very high as the input power supply charges the capacitors, resulting in inrush current. This inrush current can damage the electronic components (such as the switching devices and capacitors) in the SCC, affecting its normal operation.

[0003] During their research and practice, the inventors of this application discovered that the existing technology involves connecting a current limiting circuit in series between the input power supply and the switched capacitor converter to limit the surge current during the startup phase of the switched capacitor converter. This requires adding a current limiting circuit, resulting in a complex circuit structure and high implementation cost. Summary of the Invention

[0004] This application provides a switched capacitor converter and its surge current suppression method, which can suppress surge current directly during the startup stage without adding a current limiting circuit, through software control strategy.

[0005] In a first aspect, this application provides a switched-capacitor converter, which may include a controller, a first capacitor, n resonant cavities, and n second capacitors connected in series; wherein the first capacitor is connected in series with the n second capacitors, one of the n resonant cavities is connected across the first capacitor and one of the n second capacitors, and each resonant cavity includes at least two sets of switches connected in parallel and a resonant unit connected between the two sets of switches, where n is a positive integer greater than 1; the controller can be used to control the switching of each resonant cavity to the on or off based on the drive signal of each of the n resonant cavities when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are off, so as to suppress surge current, wherein the drive signal of any resonant cavity in the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in the resonant cavity, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from the initial duty cycle to a preset duty cycle as the number of times the target switch is turned on increases. When the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate symmetrical waveforms, the target switch can include the four switches forming the upper and lower bridge arms. When the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate complementary waveforms, the target switch can include the two switches forming the upper bridge arm. During startup, the drive signal obtained by controlling the switches in each resonant cavity to turn on or off based on the switching frequency and duty cycle of the target switches in the resonant cavity, which gradually decreases, can reduce the single-time conduction time of the switches in each switching cycle, thereby shortening the single-time charging time of the resonant capacitor and suppressing surge current during startup. Moreover, no additional current-limiting circuit is required; surge current suppression is achieved through software control strategies (i.e., controlling the drive signals of each resonant cavity), which reduces circuit cost and complexity and has high applicability.

[0006] In one feasible implementation, the aforementioned n second capacitors are connected in series between the input and output terminals of the switched capacitor converter, wherein the second capacitor connected to the input terminal is the first second capacitor, and the second capacitor connected to the output terminal is the nth second capacitor. The i-th resonant cavity among the n resonant cavities is connected in parallel across the i-th second capacitor among the n second capacitors. The controller is used to: control the switching on or off of a switch in at least one resonant cavity based on the driving signal of at least one resonant cavity among the n resonant cavities during at least one first time period. The driving signal of any resonant cavity among the at least one resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in the resonant cavity. The switching frequency of the target switch is greater than or equal to the resonant frequency of the resonant cavity, and the duty cycle of the target switch is less than or equal to a preset duty cycle. The first time period includes at least one switching cycle. The period from the k-th turn-on time of the target switch in each resonant cavity to the (k+1)-th turn-on time of the target switch is one switching cycle, where k is a positive integer. In other words, within the switching cycle included in the first time period, the controller can control the switching on or off of at least one switch in a resonant cavity. Here, at least one resonant cavity can include one resonant cavity, m (1≤m≤n) resonant cavities, or n resonant cavities, etc. In this application, the driving signal of each resonant cavity is obtained by the change of the switching frequency and duty cycle of the target switch in each resonant cavity, and the switching on or off of the switch in each resonant cavity is controlled based on the driving signal of each resonant cavity. This process can include multiple implementation schemes, that is, the direct suppression of surge current can be achieved through multiple different schemes, with high flexibility and high applicability.

[0007] In one feasible implementation, the at least one resonant cavity is the n resonant cavities, and the controller is used to: control the switching on or off of the switches in each of the n resonant cavities based on the driving signals of each resonant cavity in each switching cycle of the first time period, wherein the phase difference between the driving signals of two adjacent resonant cavities in the n resonant cavities is 360 / n degrees. Specifically, in each switching cycle, the phase difference between the driving signal of the first resonant cavity and the driving signal of the second resonant cavity is 360 / n degrees, ..., the phase difference between the driving signal of the (n-1)th resonant cavity and the driving signal of the nth resonant cavity is 360 / n degrees. Here, by keeping the n resonant cavities operating out of phase in each switching cycle, the phase difference between the multiple resonant cavities in the same switching cycle is achieved. Figure 3The switches forming the lower bridge arm shown do not conduct simultaneously, preventing the current from multiple resonant cavities from merging and causing excessive current in the first capacitor, thus reducing line losses. In this application, during each switching cycle from startup to steady state, the controller controls the n resonant cavities to operate in staggered phases based on the drive signals of each resonant cavity. The switching frequency of the target switch corresponding to each drive signal gradually decreases, and the duty cycle of the target switch gradually increases, which can directly suppress surge current. Furthermore, the control timing is the same during the startup and steady-state phases, avoiding complex switching between the two phases, reducing the possibility of circuit errors, reducing circuit complexity, and improving circuit efficiency.

[0008] In one feasible implementation, the controller is used to: control the switching on or off of a switch in one of the resonant cavities from the first to the mth resonant cavities sequentially, based on the driving signals of each resonant cavity from the first to the mth resonant cavities, within m consecutive first time periods. Here, m is an integer greater than 1 and less than or equal to n. Within the n consecutive first time periods, each resonant cavity operates sequentially for one first time period, and only one resonant cavity operates within the same first time period. Here, the process of each resonant cavity operating sequentially within the n consecutive first time periods can be called one cycle. It is understood that as the number of times the target switch is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle. This process can be completed within the aforementioned one cycle; correspondingly, the switched capacitor converter reaches a steady state after one cycle after startup. This process can also be completed in multiple cycles, which is not limited in this application. In this application, during multiple consecutive first time periods from startup to reaching steady state, the controller gradually controls one of the n resonant cavities to work based on the drive signals of each resonant cavity in the n resonant cavities, so that the switched capacitor converter gradually transitions to steady state, which can directly suppress surge current. Moreover, only one resonant cavity works during a first time period in the startup process, the control timing is simple, and the circuit complexity can be reduced.

[0009] In one feasible implementation, the controller is used to: control the switching on or off of m consecutive resonant cavities from the first to the nth resonant cavity successively, based on the driving signals of each resonant cavity from the first to the nth resonant cavity, within n / m consecutive first time periods. The phase difference between the driving signals of two adjacent resonant cavities in these m resonant cavities is 360 / m degrees, where m is greater than or equal to 2 and n is a multiple of m. The two sets of m resonant cavities corresponding to the two consecutive first time periods are different. Here, the process of controlling m resonant cavities out of n resonant cavities to work successively within n / m consecutive first time periods, so that all n resonant cavities work for one first time period, can be called one cycle. It can be understood that as the number of times the target switch is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle. This process can be completed in one cycle or in multiple cycles. In this application, during multiple consecutive first time periods from startup to reaching steady state, the controller gradually controls the operation of m consecutive resonant cavities out of the n resonant cavities based on the drive signals of each resonant cavity, enabling the switched-capacitor converter to gradually transition to steady state and directly suppressing surge current. Furthermore, having m resonant cavities operating within a single first time period during startup shortens the time required for the switching frequency and duty cycle of each target switch in the n resonant cavities to change to steady-state values, ensuring the switched-capacitor converter reaches steady state as quickly as possible.

[0010] In one feasible implementation, the aforementioned at least one first time period includes two or more first time periods. The controller is configured to: within the k-th first time period of the two or more first time periods, based on the drive signals of the 1st to the m-th resonant cavity, control the switching on or off of the switches in each of the resonant cavities from the 1st to the m-th resonant cavity respectively. The phase difference between the drive signals of two adjacent resonant cavities from the 1st to the m-th resonant cavity is 360 / m degrees, where m is greater than or equal to 2 and less than or equal to n, k is a positive integer, and m increases as k increases. In this application, during multiple first time periods from startup to reaching steady state, the controller gradually controls more resonant cavities to join other resonant cavities working together based on the drive signals of each of the n resonant cavities. The initial frequency and initial duty cycle of the drive signal of the newly added resonant cavity are different from the initial frequency and initial duty cycle of the drive signal of the previously working resonant cavity. This allows the switched capacitor converter to transition to steady state as quickly as possible, achieving direct suppression of surge current. In addition, the control timing of the controller is basically the same when it is close to steady state as the control timing in steady state. When steady state is reached, the control timing can be switched, which can improve the circuit efficiency.

[0011] In one feasible implementation, as the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, where the first resonant cavity is any one of the n resonant cavities. That is, the changes in the duty cycle and switching frequency of the target switch in the first resonant cavity occur simultaneously. In this way, while suppressing surge current during startup, the time required for the duty cycle and switching frequency of the target switches in each resonant cavity to reach steady-state values ​​can be shortened, ensuring that the switched capacitor converter can transition from the startup phase to steady state as quickly as possible.

[0012] In one feasible implementation, after the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity; or, after the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle; wherein, the first resonant cavity is any one of the n resonant cavities. That is, the changes in the duty cycle and switching frequency of the target switch in the first resonant cavity are performed sequentially. In this way, while suppressing surge current during the startup phase, the complexity of the control timing can be reduced, the flexibility of the scheme can be increased, and its applicability is high.

[0013] In one feasible implementation, the switched-capacitor converter further includes n first resistors, one of which is connected in parallel with one of the n second capacitors. The initial frequencies corresponding to the driving signals of each of the n resonant cavities are equal. The resistance values ​​of each of the n first resistors can be equal. Here, before the controller of the switched-capacitor converter starts operating any resonant cavity, the first resistors connected in parallel with each of the n second capacitors ensure that the n second capacitors evenly distribute the input voltage. This creates the necessary conditions for even current distribution through the resonant capacitors in each resonant cavity during the startup and steady-state process of the switched-capacitor converter.

[0014] In one feasible implementation, each of the n resonant cavities includes at least one resonant capacitor as its resonant unit. The controller is further configured to: generate a drive signal for each resonant cavity based on the duty cycle of the target switch in each of the n resonant cavities; the drive signal for each resonant cavity is used to control the switching on or off of the switches in each resonant cavity so that the current through the resonant capacitors in the n resonant cavities is equal; the duty cycle of the target switch in each resonant cavity increases from an initial duty cycle to a preset duty cycle by a target step size; at least two of the n initial duty cycles corresponding to the drive signal of each resonant cavity are different; and the target step size corresponding to the drive signal of each resonant cavity is obtained based on the initial duty cycle corresponding to the drive signal of each resonant cavity. By differentiating the initial duty cycles corresponding to the drive signals of each of the n resonant cavities when the switched capacitor converter starts up, and by differentiating the target step size corresponding to the drive signals of each resonant cavity, the voltage difference between the second capacitor connected to each resonant cavity and the resonant capacitor in the resonant cavity can be made as consistent as possible, thereby achieving the purpose of equalizing the current flowing through the resonant capacitors in each resonant cavity.

[0015] Secondly, this application provides a surge current suppression method for a switched-capacitor converter, applied to a controller in the switched-capacitor converter. The switched-capacitor converter further includes a first capacitor, n resonant cavities, and n second capacitors connected in series. The first capacitor is connected in series with the n second capacitors. One of the n resonant cavities is connected across the first capacitor and one of the n second capacitors. Each resonant cavity includes at least two sets of switches connected in parallel and a resonant unit connected between the two sets of switches. n is a positive integer greater than 1. The method includes: in the switch... When the capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are turned off, the switching in each resonant cavity is controlled to turn on or off based on the driving signal of each of the n resonant cavities to suppress surge current. The driving signal of any of the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in the resonant cavity. The switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle as the number of times the target switch is turned on increases.

[0016] In one feasible implementation, n second capacitors are connected in series between the input and output terminals of the switched capacitor converter. The second capacitor connected to the input terminal is the first second capacitor, and the second capacitor connected to the output terminal is the nth second capacitor. The ith resonant cavity among the n resonant cavities is connected in parallel across the ith second capacitor. The above-mentioned control of the switching on or off of the switches in each resonant cavity based on the driving signal of each resonant cavity among the n resonant cavities includes: controlling the switching on or off of the switches in at least one resonant cavity based on the driving signal of at least one resonant cavity among the n resonant cavities within at least one first time period. The driving signal of any resonant cavity among the at least one resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in the resonant cavity. The switching frequency of the target switch is greater than or equal to the resonant frequency of the resonant cavity, and the duty cycle of the target switch is less than or equal to a preset duty cycle. The first time period includes at least one switching cycle. The period from the kth turn-on time of the target switch in each resonant cavity to the (k+11)th turn-on time of the target switch is one switching cycle, where k is a positive integer.

[0017] In one feasible implementation, the at least one resonant cavity is n resonant cavities, and the control of the switching on or off of the switch in the at least one resonant cavity based on the driving signal of the at least one resonant cavity in the n resonant cavities during at least one first time period includes: controlling the switching on or off of the switch in each resonant cavity based on the driving signal of each resonant cavity in the n resonant cavities during each switching cycle of the first time period, wherein the phase difference between the driving signals of two adjacent resonant cavities in the n resonant cavities is 360 / n degrees.

[0018] In one feasible implementation, the above-mentioned control of the switching on or off of a switch in at least one resonant cavity based on the driving signal of at least one resonant cavity among n resonant cavities during at least one first time period includes: controlling the switching on or off of a switch in one of the resonant cavities from the first resonant cavity to the mth resonant cavity sequentially based on the driving signal of each resonant cavity from the first resonant cavity to the mth resonant cavity during m consecutive first time periods, wherein m is an integer greater than 1 and less than or equal to n.

[0019] In one feasible implementation, the above-mentioned control of the switching on or off of a switch in at least one resonant cavity based on the driving signal of at least one resonant cavity among n resonant cavities within at least one first time period includes: within n / m consecutive first time periods, based on the driving signals of each resonant cavity from the 1st resonant cavity to the nth resonant cavity, successively controlling the switching on or off of the switches of m consecutive resonant cavities from the 1st resonant cavity to the nth resonant cavity, wherein the phase difference between the driving signals of two adjacent resonant cavities among the m resonant cavities is 360 / m degrees, m is greater than or equal to 2 and n is a multiple of m, and the two consecutive first time periods correspond to two different sets of m resonant cavities.

[0020] In one feasible implementation, the aforementioned at least one first time period includes two or more first time periods. The aforementioned control of the switching on or off of a switch in at least one resonant cavity based on the driving signal of at least one of the n resonant cavities within the aforementioned at least one first time period includes: within the k-th first time period of the aforementioned two or more first time periods, controlling the switching on or off of a switch in each of the resonant cavities from the 1st to the mth resonant cavity based on the driving signals of the 1st to the mth resonant cavity, wherein the phase difference between the driving signals of two adjacent resonant cavities from the 1st to the mth resonant cavity is 360 / m degrees, m is greater than or equal to 2 and less than or equal to n, k is a positive integer, and m increases as k increases.

[0021] In one feasible implementation, as the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, where the first resonant cavity is any one of n resonant cavities.

[0022] In one feasible implementation, after the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity; or, after the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle; wherein, the first resonant cavity is any one of n resonant cavities.

[0023] In one feasible implementation, the switched capacitor converter further includes n first resistors, one of the n first resistors is connected in parallel with one of the n second capacitors, and the initial frequencies corresponding to the driving signals of each of the n resonant cavities are equal.

[0024] In one feasible implementation, each of the n resonant cavities includes at least one resonant capacitor in its resonant unit. Before controlling the switching on or off of the switches in each resonant cavity based on the driving signals of each of the n resonant cavities, the method further includes: generating a driving signal for each resonant cavity based on the duty cycle of the target switch in each of the n resonant cavities; the driving signal of each resonant cavity is used to control the switching on or off of the switches in each resonant cavity so that the current through the resonant capacitors in the n resonant cavities is equal; the duty cycle of the target switch in each resonant cavity increases from an initial duty cycle to a preset duty cycle by a target step size; at least two of the n initial duty cycles corresponding to the driving signals of each resonant cavity are different; and the target step size corresponding to the driving signals of each resonant cavity is obtained based on the initial duty cycle corresponding to the driving signals of each resonant cavity.

[0025] In this application, during the startup of the switched-capacitor converter, an initial drive signal is obtained based on the high initial frequency and small duty cycle of the target switch in each resonant cavity to control the operation of each resonant cavity. Real-time drive signals are then obtained to control the operation of each resonant cavity by gradually decreasing the switching frequency of the target switch and increasing the duty cycle to the steady-state frequency (i.e., resonant frequency) and duty cycle (i.e., preset duty cycle), thus achieving a transition from startup to steady state. During this process, changes in the switching frequency and duty cycle of the target switch can shorten the single-conduction time of the switch in each resonant cavity within each switching cycle, thereby limiting inrush current. This application eliminates the need for additional current-limiting circuits, directly suppressing inrush current through software control strategies, reducing circuit cost and complexity, improving circuit efficiency, and offering high applicability. Furthermore, this application can utilize a first resistor to evenly divide the input voltage among n second capacitors, and by differentially setting the initial duty cycle corresponding to the drive signal of each of the n resonant cavities and the target step size used to represent the duty cycle change rate, the current flowing through the resonant capacitors in each resonant cavity during the startup phase can be made as uniform as possible. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an application scenario of the switched capacitor converter provided in this application;

[0027] Figure 2 This is a schematic diagram of the switched capacitor converter provided in this application;

[0028] Figure 3 This is another structural schematic diagram of the switched capacitor converter provided in this application;

[0029] Figure 4 This is another structural schematic diagram of the switched capacitor converter provided in this application;

[0030] Figure 5 This is another structural schematic diagram of the switched capacitor converter provided in this application;

[0031] Figure 6 This is a schematic flowchart of the surge current suppression method for the switched capacitor converter provided in this application. Detailed Implementation

[0032] A switched-capacitor converter (SCC) is a voltage converter and also a direct current (DC) / DC converter. It relies on capacitors to achieve energy transfer and voltage conversion. A typical SCC includes multiple capacitors, switching devices, and inductors. The inductor can resonate with the capacitors, providing the conditions for soft switching of the switching devices. In steady-state operation, the voltage across the capacitor is a DC voltage plus the ripple voltage generated by the capacitor's charging and discharging. During startup, the voltage across the capacitor is usually zero, so it needs to be gradually charged to the steady-state voltage. However, during startup, the peak current flowing through the SCC can be very high as the input power supply charges the capacitors, resulting in inrush current. Inrush current can damage electronic components (such as switching devices and capacitors) in the SCC, affecting its normal operation. Typically, a current limiting circuit can be connected in series between the input power supply and the switched capacitor converter to limit the inrush current during the startup phase of the switched capacitor converter. However, this method requires the addition of a current limiting circuit, resulting in a complex circuit structure and high implementation cost.

[0033] The switched-capacitor converter provided in this application is applicable to various DC-DC conversion scenarios. Specifically, it can be applied to DC-DC conversion scenarios requiring low-voltage, high-current output (such as powering powerful chips like AI chips), and to DC-DC conversion scenarios requiring high-power-density power supplies (such as powering analog and digital circuits within a chip). Please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of the switched-capacitor converter provided in this application. The switched-capacitor converter provided in this application can be applied in power supply modules, such as... Figure 1 As shown, this power supply module can include a DC power supply (also known as an input power supply), a switched capacitor converter, and a point-of-load (POL) power supply. This power supply module can act as a power source to power loads such as chips, analog circuits within the chips, and digital circuits. The input voltage (e.g., 40V-60V) provided by the DC power supply undergoes DC-DC conversion (e.g., step-down) by the switched capacitor converter to obtain an intermediate voltage (e.g., 3.2V-12V) output to the POL. The POL then converts this intermediate voltage to a smaller voltage (e.g., 0.7V-1.8V) to power the load. It can be understood that, as... Figure 1 The application scenario shown is an example of the application scenario of the switched capacitor converter provided in this application, and does not constitute a limitation on this application.

[0034] This application provides a switched-capacitor converter, which includes a controller. When the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities of the converter are off, the controller controls the switching on or off of the switches in each of the n resonant cavities based on the drive signals of each resonant cavity to suppress inrush current. The drive signals of each resonant cavity are obtained based on the switching frequency and duty cycle of the target switch in that cavity. The switching frequency and duty cycle of the target switch gradually decrease from a large frequency value to the steady-state frequency, and gradually increase from a small duty cycle value to the steady-state duty cycle, respectively. This switched-capacitor converter does not add an additional current-limiting circuit. Instead, it controls the drive signals of the switching devices in each resonant cavity during startup, achieving high-frequency and low-duty-cycle startup. This reduces the on-time of the switching devices in each switching cycle, reduces the single charging time of the resonant capacitor, and avoids excessive current exceeding the limit during charging of the resonant capacitor using the input voltage, thereby limiting inrush current. This application eliminates the need for additional current-limiting circuits. It achieves the limitation of surge current during startup through software control strategies (i.e., controlling the drive signals of each resonant cavity), which reduces circuit implementation costs and complexity, and has high applicability.

[0035] The following will combine Figures 2 to 5 An example of the switched capacitor converter provided in this application is given.

[0036] See Figure 2 , Figure 2 A schematic diagram of the switched capacitor converter provided in this application is shown below. Figure 2 As shown, the switched capacitor converter may include a controller, a first capacitor (e.g., first capacitor C0), n resonant cavities (e.g., resonant cavity 1 to resonant cavity n), and n second capacitors (e.g., second capacitors C1 to second capacitor Cn) connected in series. The first capacitor is connected in series with the aforementioned n second capacitors. One of the n resonant cavities is connected across the first capacitor and one of the n second capacitors. Each resonant cavity includes at least two sets of switches connected in parallel and a resonant element connected between the two sets of switches. n is a positive integer greater than 1. In other words, one of the resonant cavities 1 to resonant cavity n can correspond to one of the second capacitors C1 to second capacitor Cn. For example, as... Figure 2 As shown, the input terminal of resonant cavity 1 can be connected in parallel to the second capacitor C1, and the output terminal of resonant cavity 1 can be connected in parallel to the first capacitor C0; ...; the input terminal of resonant cavity n can be connected in parallel to the second capacitor Cn, and the output terminal of resonant cavity n can be connected in parallel to the first capacitor C0. The above switched capacitor converter can be a buck converter (such as...). Figure 2As shown in the diagram, the voltage across the second capacitors C1 to Cn is the input voltage (Vin) of the switched capacitor converter. One end of the first capacitor is connected to n second capacitors connected in series, and the other end can be grounded (GND). In this case, the first capacitor can be the output capacitor, i.e., the voltage across the first capacitor C0 is the output voltage (Vout) of the switched capacitor converter. Optionally, the switched capacitor converter can be a boost converter, in which case the first capacitor can be the input capacitor, i.e., the voltage across the first capacitor C0 is the input voltage of the switched capacitor converter, and the voltage across the second capacitors C1 to Cn is the output voltage of the switched capacitor converter. For ease of description, this application uses the switched capacitor converter as a buck converter (e.g., ...). Figure 2 The following is an example for description (shown in the image).

[0037] In some feasible implementations, the resonant units in each of the above-mentioned resonant cavities may include a resonant inductor and a resonant capacitor connected in series. Optionally, the resonant unit in each resonant cavity may also include a resonant capacitor, a resonant inductor, and another capacitor, wherein the resonant capacitor is connected in series with the resonant inductor, and the two ends of the resonant inductor are connected in parallel with the other capacitor. That is to say, the specific forms of the resonant units in each resonant cavity include various types, and this application does not impose any limitations. For ease of description, the following description uses the example of resonant units in each resonant cavity including a resonant inductor and a resonant capacitor connected in series. Please refer to [further details omitted]. Figure 3 , Figure 3 This is another structural schematic diagram of the switched capacitor converter provided in this application. For example... Figure 3 As shown, Figure 2 The resonant cavity 1 includes a resonant unit 1-1, which includes a resonant inductor Lr1 and a resonant capacitor Cr1 connected in series. The two sets of parallel switches included in the resonant cavity 1 can be... Figure 3 The circuit includes switches S11, S21, S31, and S41. The series connection point of switches S11 and S21 can be connected to the series connection point of switches S31 and S41 via a resonant inductor Lr1 and a resonant capacitor Cr1. Switches S11, S21, S31, S41, the resonant inductor Lr1, and the resonant capacitor Cr1 can form a bridge resonant circuit (referred to as a resonant cavity in this application). ... For example... Figure 3 As shown, the resonant cavity n includes resonant units 1-n, each containing a resonant inductor Lrn and a resonant capacitor Crn connected in series. The two sets of parallel switches included in the resonant cavity n can be... Figure 3The circuit includes switches S1n, S2n, S3n, and S4n. The series connection point of switches S1n and S2n can be connected to the series connection point of switches S3n and S4n via resonant inductor Lrn and resonant capacitor Crn. Switches S1n, S2n, S3n, S4n, resonant inductor Lrn, and resonant capacitor Crn can form a bridge resonant circuit. The two sets of parallel-connected switches in each resonant cavity can be MOSFETs, IGBTs, or relays made of silicon semiconductor material (Si), third-generation wide-bandgap semiconductor material silicon carbide (SiC), gallium nitride (GaN), diamond, zinc oxide (ZnO), or other materials. The specific choice depends on the actual application scenario and is not limited here. When the switches included in the resonant cavity are MOSFETs, the controller can connect to the gate of each switch in each resonant cavity to control the switching on or off of each switch; when the switches included in the resonant cavity are IGBTs, the controller can connect to the base of each switch to control the switching on or off of each switch. In other words, the controller can control the switching on or off of each switch in each resonant cavity based on the drive signal of each resonant cavity.

[0038] In some feasible implementations, such as Figure 3 As shown, the capacitance value of the first capacitor C0 can be greater than the capacitance value of any one of the second capacitors C1 to Cn. Taking n=3 as an example, the number of second capacitors in this switched capacitor converter is 3, and the corresponding number of resonant cavities is 3. The structure of this switched capacitor converter is as follows. Figure 4 As shown. The drive signals of the n resonant cavities in this switched-capacitor converter can be in phase or out of phase (i.e., the phase difference between the drive signals is not zero). Taking the in-phase drive signals of all resonant cavities as an example, the complete cycle of any one of the multiple switches (also called switching devices) included in each resonant cavity includes a first cycle, a second cycle, and a dead zone, where the first and second cycles are close to half of the complete cycle. The steady-state operating principle of this switched-capacitor converter is as follows: In the first cycle, the two switches forming the upper bridge arm (i.e., ...) of the four switches included in each resonant cavity... Figure 4 Switches S11 and S31, S12 and S32, and S13 and S33 in the middle are turned on, forming the two switches of the lower bridge arm (i.e., Figure 4Switches S21, S41, S22, S42, S23, and S43 in the resonant cavity are turned off, and the second capacitors C3, C2, and C1 charge the resonant capacitors Cr3, Cr2, and Cr1 in the resonant cavity, respectively; the input voltage Vin charges the first capacitor C0 through the three resonant cavities. In the second cycle, the two switches forming the lower bridge arm of each resonant cavity (i.e., Figure 4 Switches S21 and S41, S22 and S42, and S23 and S43 in the middle are turned on, forming the two switches of the upper bridge arm (i.e., Figure 4 When switches S11, S31, S12, S32, S13, and S33 are turned off, the resonant capacitors Cr3, Cr2, and Cr1 in the resonant cavity charge the first capacitor C0. Therefore, the voltage across the first capacitor C0 is equal to the voltages across the second capacitors C3, C2, and C1, respectively. Since the sum of the voltages across the three series-connected second capacitors and the first capacitor C0 equals the input voltage Vin, the voltage across the first capacitor C0 is one-quarter of the input voltage Vin. This means the switched capacitor converter achieves a 4:1 input-output voltage conversion, thus achieving voltage reduction. Understandably, when the switched capacitor converter operates in steady state, the controller controls the switches in each resonant cavity to turn on or off based on the drive signal (also called the control signal). The switching frequency of the switches in each resonant cavity is the resonant frequency of that cavity, and the duty cycle of the switches is close to 0.5, a stable value (this duty cycle can be referred to as the preset duty cycle in this application).

[0039] In some feasible implementations, the controller in the switched-capacitor converter is used to control the switching of each switch in each of the n resonant cavities to be turned on or off based on the drive signal of each of the n resonant cavities when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are off (i.e., when the switched-capacitor converter is started), in order to suppress inrush current. The drive signal of any of the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity. The switching frequency of the target switch decreases from an initial frequency to the resonant frequency of the resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from an initial duty cycle to a preset duty cycle as the number of times the target switch is turned on increases. This preset duty cycle can be the duty cycle reached by the target switch when the switched-capacitor converter is operating in a steady state. Specifically, when the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate symmetrical waves, the duty cycles of the two switches forming the upper bridge arm and the two switches forming the lower bridge arm are always equal, and the phase difference between the driving signals corresponding to the upper bridge arm and the lower bridge arm is 180 degrees. Here, the target switch can include the four switches forming the upper and lower bridge arms. When the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate complementary waves, the duty cycles of the two switches forming the upper bridge arm and the two switches forming the lower bridge arm are complementary. The target switch can include the two switches forming the upper bridge arm. The driving signals of each resonant cavity can include the driving signals corresponding to the two switches forming the upper bridge arm and the driving signals corresponding to the two switches forming the lower bridge arm. Understandably, when the switching frequencies of the switches in each resonant cavity all reach the resonant frequency of the resonant cavity, and the duty cycles of the switches in each resonant cavity all reach the preset duty cycles, the switched capacitor converter reaches a steady state. In other words, in this application, during the process of the switched-capacitor converter from startup to reaching steady state, the controller of the switched-capacitor converter controls the switches in each resonant cavity to turn on or off based on a specific drive signal. This specific drive signal is obtained based on the switching frequency and duty cycle of the target switch in each resonant cavity. The switching frequency of the target switch decreases from an initial frequency (which is greater than the resonant frequency of the resonant cavity) to the resonant frequency of the resonant cavity, while the duty cycle of the target switch increases from an initial duty cycle (which is less than a preset duty cycle) to a preset duty cycle. By controlling the switches in each resonant cavity to turn on or off based on the drive signal obtained from the decreasing switching frequency and increasing duty cycle of the target switch in the resonant cavity during startup, the single-time conduction time of the switch can be reduced in each switching cycle, thereby shortening the single-time charging time of the resonant capacitor and suppressing inrush current during startup. This application eliminates the need for additional current-limiting circuits; inrush current suppression can be achieved directly by controlling the drive signal, reducing circuit cost and complexity, and offering high applicability.

[0040] In some feasible implementations, the aforementioned n second capacitors are connected in series between the input and output terminals of the switched capacitor converter, wherein the second capacitor connected to the input terminal is the first second capacitor, the second capacitor connected to the output terminal is the nth second capacitor, and the ith resonant cavity among the n resonant cavities is connected in parallel across the ith second capacitor among the n second capacitors. For example... Figure 3 As shown, the second capacitors C1, ..., Cn are the first, ..., nth second capacitors, respectively, and the resonant cavities 1, ..., n are the first, ..., nth resonant cavities, respectively. The controller in the switched-capacitor converter can be used to: control the switching on or off of the switches in the at least one resonant cavity based on the drive signal of at least one of the n resonant cavities within at least a first time period. The drive signal of any one of the at least one resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity. The switching frequency of the target switch is greater than or equal to the resonant frequency of the resonant cavity, and the duty cycle of the target switch is less than or equal to the preset duty cycle. The first time period includes at least one switching cycle, and the period from the kth turn-on time of the target switch in each resonant cavity to the (k+1)th turn-on time of the target switch constitutes one switching cycle, where k is a positive integer. It is understood that the first time period is a certain time period during the process of the switched capacitor reaching a steady state from startup, and the first time period includes at least one switching cycle. In other words, within the switching cycle included in the first time period, the controller can control the switching on or off of the switches in at least one resonant cavity. Here, "at least one resonant cavity" can include one resonant cavity, m (1≤m≤n) resonant cavities, or n resonant cavities, etc. The following details how the controller controls the switching on or off of the switches in each resonant cavity under these different conditions. The driving signal for each resonant cavity is obtained by the change in the switching frequency and duty cycle of the target switch in each resonant cavity, and the switching on or off of the switches in each resonant cavity is controlled based on the driving signal. This process can include multiple implementation schemes; that is, direct suppression of surge current can be achieved through various different schemes, offering high flexibility and applicability.

[0041] In some feasible implementations, the at least one resonant cavity is actually n resonant cavities. The controller can be used to control the switching on or off of the switches in each of the n resonant cavities based on the driving signals of each resonant cavity in each switching cycle of the first time period. The phase difference between the driving signals of any two adjacent resonant cavities in the n resonant cavities is 360 / n degrees. That is, in each switching cycle of each first time period, the controller controls all n resonant cavities to operate (i.e., controls the switching on or off of the switches in the resonant cavities), and the phase difference between the driving signals of any two adjacent resonant cavities is 360 / n degrees. Specifically, in each switching cycle, the phase difference between the driving signal of the first resonant cavity and the driving signal of the second resonant cavity is 360 / n degrees, ..., the phase difference between the driving signal of the (n-1)th resonant cavity and the driving signal of the nth resonant cavity is 360 / n degrees. Here, by keeping the n resonant cavities operating out of phase in each switching cycle, the ripple of the output current can be reduced. Furthermore, in the same switching cycle, the phase difference between the driving signals of multiple resonant cavities is... Figure 3 The switches that make up the lower bridge arm shown will not be turned on simultaneously (e.g.) Figure 3When switches S21 and S41 are turned on, switches S2n and S4n will not be turned on. This avoids the current from multiple resonant cavities merging to the first capacitor, which would cause excessive current and thus reduce line losses. The aforementioned first time period can include the entire process from startup to steady state. That is, during each switching cycle from startup to steady state, the controller controls the switching on or off of the switches in each of the n resonant cavities based on the drive signals of each resonant cavity. The drive signal of each resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity. Before the switched-capacitor converter reaches steady state, as the number of times the target switch in each resonant cavity is turned on increases, the switching frequency of the target switch in each resonant cavity decreases from the initial frequency to the resonant frequency of that resonant cavity, and the duty cycle of the target switch increases from the initial duty cycle to the aforementioned preset duty cycle. Understandably, to maintain a constant phase difference in each switching cycle, the initial frequencies of the target switches in each resonant cavity are equal, and the rate of change of the switching frequency of the target switches in each resonant cavity (i.e., the rate of decrease from the initial frequency to the resonant frequency) remains consistent. The initial duty cycles of the target switches in each resonant cavity can be equal or unequal, depending on the actual situation, and this application does not impose any restrictions. In each switching cycle from startup to reaching steady state, the controller controls the n resonant cavities to operate in staggered phase based on the drive signals of each resonant cavity in the n resonant cavities. The switching frequency of the target switch corresponding to each drive signal gradually decreases, and the duty cycle of the target switch gradually increases, which can directly suppress surge current. Moreover, since the n resonant cavities of the switched capacitor converter operate in each switching cycle (and all operate in staggered phase) during both the startup and steady-state phases, the control timing is the same during the startup and steady-state phases. This avoids complex switching of operating modes between the two phases, reduces the possibility of circuit errors, reduces circuit complexity, and improves circuit efficiency.

[0042] In some feasible implementations, the at least one resonant cavity can be a single resonant cavity, and the at least one first time period can include m consecutive first time periods. The controller of the switched capacitor converter can be used to: within the m consecutive first time periods, based on the driving signals of each resonant cavity from the first resonant cavity to the mth resonant cavity, successively control the switching on or off of a switch in one of the n resonant cavities. Here, m is an integer greater than 1 and less than or equal to n. For example, when m = n, the controller can, within the n consecutive first time periods, successively control the switching on or off of a switch in one of the n resonant cavities based on the driving signals of each resonant cavity from the first resonant cavity to the nth resonant cavity. For example, in the first time period, the drive signal of the first resonant cavity controls the switch in that cavity to operate; in the second time period, the drive signal of the second resonant cavity controls the switch in that cavity to operate; ...; in the nth time period, the drive signal of the nth resonant cavity controls the switch in that cavity to operate. In the n consecutive time periods, each resonant cavity operates sequentially for one time period, with only one resonant cavity operating within the same time period. This process of each of the n resonant cavities operating sequentially within the n consecutive time periods can be called one cycle. The switched-capacitor converter can undergo one or more cycles from startup to steady state, depending on the specific application scenario. The drive signal for each resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in that cavity, and the first time period can include one or more switching cycles. It is understood that as the number of times the target switch is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle. This process can be completed in one cycle, and correspondingly, the switched capacitor converter reaches a steady state after one cycle after startup; this process can also be completed in multiple cycles, and correspondingly, the switched capacitor converter reaches a steady state after multiple cycles after startup. This application does not impose any limitations. In some embodiments, it is assumed that the process of the switching frequency of the target switch in each resonant cavity decreasing from the initial frequency to the resonant frequency and the duty cycle of the target switch increasing from the initial duty cycle to the preset duty cycle is completed in multiple cycles, and the total number of cycles is denoted as s (s is an integer greater than or equal to 2). For any one of the n resonant cavities, for example, the switching frequency and duty cycle of the target switch in that resonant cavity can change as follows: In the first cycle, the switching frequency f decreases from f1 (representing the initial frequency) to f2, and the duty cycle D increases from D1 (representing the initial duty cycle) to D2; in the second cycle, the switching frequency f decreases from f2 to f3, and the duty cycle D increases from D2 to D3; ...; in the s-th cycle, the switching frequency f decreases from f1 to f2. s-1 Decrease to fs (Represents the resonant frequency of the resonant cavity), the duty cycle D from D s-1 Increment to D s (This represents the preset duty cycle mentioned above). In this case, within each of the s cycles, the switching frequency and duty cycle of the target switch in the resonant cavity change. Optionally, another variation in the switching frequency and duty cycle of the target switch in the resonant cavity could be: within each of the first t (t < s) cycles, the switching frequency of the target switch in the resonant cavity changes, while the duty cycle remains constant; within each of the last st cycles, the duty cycle of the target switch in the resonant cavity changes, while the switching frequency remains constant. Alternatively, within each of the first t (t < s) cycles, the duty cycle of the target switch in the resonant cavity changes, while the switching frequency remains constant; within each of the last st cycles, the switching frequency of the target switch in the resonant cavity changes, while the duty cycle remains constant. In other words, if the switched capacitor converter reaches a steady state after undergoing the above multiple cycles after startup, the process of the switching frequency and duty cycle of the target switch in each resonant cavity changing to the resonant frequency and preset duty cycle includes various different cases, which this application does not limit. In this application, during multiple consecutive first time periods from startup to reaching steady state, the controller gradually controls one of the n resonant cavities to work based on the drive signals of each resonant cavity in the n resonant cavities, so that the switched capacitor converter gradually transitions to steady state, which can directly suppress surge current. Moreover, only one resonant cavity works during a first time period in the startup process, the control timing is simple, and the circuit complexity can be reduced.

[0043] In some feasible implementations, the at least one resonant cavity can be m resonant cavities, and the at least one first time period can include n / m consecutive first time periods. The controller in the switched capacitor converter can be used to: within the n / m consecutive first time periods, based on the driving signals of each resonant cavity from the first resonant cavity to the nth resonant cavity, successively control the switching on or off of the m consecutive resonant cavities from the first resonant cavity to the nth resonant cavity. Wherein, the phase difference between the driving signals of two adjacent resonant cavities in the m resonant cavities is 360 / m degrees, m is greater than or equal to 2, and n is a multiple of m. The two consecutive first time periods correspond to two different sets of m resonant cavities. For example, when n = 3m, the controller can, within three consecutive first time periods, successively control the switching on or off of the m resonant cavities in these n resonant cavities based on the driving signals of each resonant cavity from the first resonant cavity to the nth resonant cavity. For example, in the first time period, based on the driving signals of each resonator from the 1st to the mth resonator, the switches in the 1st to the mth resonator are controlled to be turned on or off; in the second time period, based on the driving signals of each resonator from the (m+1)th to the 2mth resonator, the switches in the (m+1)th to the 2mth resonator are controlled to be turned on or off; in the third time period, based on the driving signals of each resonator from the (2m+1)th to the 3mth resonator, the switches in the (2m+1)th to the 3mth resonator are controlled to be turned on or off. In a series of n / m time periods, the m resonators in the n resonators work sequentially for one time period. Only m resonators work within the same time period, and the two sets of m resonators corresponding to any two time periods are different. Here, the process of successively controlling m of the n resonant cavities within n / m consecutive first time periods, so that all n resonant cavities operate for one first time period, can be called one cycle. The switched-capacitor converter can undergo one or more cycles from startup to steady state, depending on the specific application scenario. The driving signal for each resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in that cavity. The first time period can include one or more switching cycles. It can be understood that as the number of times the target switch is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle. This process can be completed in the aforementioned one cycle, and correspondingly, the switched-capacitor converter reaches steady state after startup through one cycle; this process can also be completed in multiple cycles, and correspondingly, the switched-capacitor converter reaches steady state after startup through multiple cycles. This application does not impose any limitations. In some embodiments, it is assumed that the change process of the switching frequency and duty cycle of the target switch in each resonant cavity is completed in the aforementioned multiple cycles.If, in the i-th cycle of the multiple cycles, the switching frequency f and duty cycle D of the target switch in the m out-of-phase resonant cavities of the n resonant cavities change to f respectively. i and D i Therefore, in the (i+1)th cycle of this multi-cycle process, the switching frequency f and duty cycle D of the target switches in the m resonant cavities respectively change from the aforementioned f i and D i The process continues. In each cycle, the switching frequency and duty cycle of the target switch in each of the m consecutive resonant cavities operating within the same first time period can change consistently. In this application, during multiple consecutive first time periods from startup to reaching steady state, the controller, based on the drive signals of each of the n resonant cavities, gradually controls the operation of the m consecutive resonant cavities, allowing the switched-capacitor converter to gradually transition to steady state, thus directly suppressing surge current. Furthermore, having m resonant cavities operating within a single first time period during startup shortens the time required for the switching frequency and duty cycle of each target switch in the n resonant cavities to reach steady-state values, ensuring the switched-capacitor converter reaches steady state as quickly as possible.

[0044] In some feasible implementations, the aforementioned at least one first time period includes two or more first time periods. The controller in the switched capacitor converter can be used to: control the switching on or off of the switches in each of the aforementioned resonant cavities from the first resonant cavity to the m-th resonant cavity respectively, based on the driving signals of the aforementioned first resonant cavity to the m-th resonant cavity, during the k-th first time period of the aforementioned two or more first time periods; wherein, the phase difference between the driving signals of two adjacent resonant cavities from the aforementioned first resonant cavity to the aforementioned m-th resonant cavity is 360 / m degrees, the aforementioned m is greater than or equal to 2, and the aforementioned m is less than or equal to the aforementioned n, the aforementioned k is a positive integer, and the aforementioned m increases as the aforementioned k increases. For example, assuming n=6, in each switching cycle of the first time period, the switching on or off of the first and second resonant cavities can be controlled based on the driving signals of each resonant cavity in the first and second resonant cavities. The phase difference between the driving signals of these two resonant cavities is 180 degrees, and k=1, m=2. In each switching cycle of the second time period, the first resonant cavity can be controlled based on the driving signals of each resonant cavity in the first to fourth resonant cavities. The phase difference between the driving signals of two adjacent resonant cavities is 90 degrees when the switch in the fourth resonant cavity is turned on or off, at which point k = 2 and m = 4. During each switching cycle of the third first time period, the switching on or off of the switches in the first to sixth resonant cavities can be controlled based on the driving signals of each resonant cavity, with a phase difference of 60 degrees between the driving signals of two adjacent resonant cavities, at which point k = 3 and m = 6. Here, the process of gradually controlling more resonant cavities to join the operation during the above two or more first time periods, so that the number of resonant cavities operating in phase out simultaneously increases from the minimum value of m to n, can be called one cycle. After the switched capacitor converter starts up, it can reach steady state after one cycle. The driving signal of each resonant cavity is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity, and the first time period may include one or more switching cycles. During the aforementioned cycle, as the number of times the target switch in each resonant cavity is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency, while the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle. The initial frequency and initial duty cycle of each resonant cavity are different. Specifically, the initial frequency of the newly added resonant cavity in the k-th first time period is equal to the switching frequency reached by the target switch in the m resonant cavities operating in the (k-1)-th first time period, and the initial duty cycle of the newly added resonant cavity in the k-th first time period is equal to the duty cycle reached by the target switch in the m resonant cavities operating in the (k-1)-th first time period.For example, assuming n = 6, during the first time period, the switching frequencies f of the target switches in the first and second resonant cavities both decrease from f1 to f2, and the duty cycles D both increase from D1 to D2. The controller obtains the respective drive signals for the two resonant cavities based on the switching frequencies and duty cycles of the target switches, and drives the switches in each resonant cavity to turn on or off based on their respective drive signals. Then, during the second time period, the switching frequencies f of the target switches in the first and second resonant cavities both decrease from f2 to f3, and the duty cycles D both increase from D2 to D3. The switching frequencies f of the target switches in the newly added third and fourth resonant cavities can both directly change from f2 and then decrease to f3, and the duty cycles D of the target switches can both directly change from D2 and then increase to D3. The controller obtains the driving signals for each of the target switches in the first to fourth resonant cavities based on their switching frequencies and duty cycles, and then drives the switches in each resonant cavity to turn on or off based on these driving signals. Accordingly, during the third first time period, the switching frequencies f of the target switches in the first to fourth resonant cavities decrease from f3 to f4, and the duty cycles D increase from D3 to D4. The switching frequencies f of the target switches in the newly added fifth and sixth resonant cavities can directly change from f3, then decrease to f4, and the duty cycles D of the target switches can directly change from D3, then increase to D4. The controller obtains the driving signals for each of the target switches in the first to sixth resonant cavities based on their switching frequencies and duty cycles, and then drives the switches in each resonant cavity to turn on or off based on these driving signals. Understandably, the initial frequencies and initial duty cycles of the first and second, third and fourth, and fifth and sixth resonant cavities mentioned above are different. However, the times when the switching frequency of the target switch in these six resonant cavities reaches the resonant frequency and the time when the duty cycle reaches the preset duty cycle are basically close. In this application, during multiple first time periods from startup to reaching steady state, the controller, based on the drive signals of each of the n resonant cavities, gradually controls more resonant cavities to join other resonant cavities to work together. The initial frequency and initial duty cycle corresponding to the drive signals of the newly added resonant cavities are different from those corresponding to the drive signals of the previously working resonant cavities. This allows the switched capacitor converter to transition to steady state as quickly as possible, achieving direct suppression of surge current. In addition, the control timing of the controller when approaching steady state is basically the same as the control timing during the steady state stage. When steady state is reached, switching of control timing can be avoided, which can improve circuit efficiency.

[0045] In some feasible implementations, any one of the n resonant cavities can be referred to as the first resonant cavity. During the process of the target switch in the first resonant cavity increasing its duty cycle from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity can decrease from the initial frequency to the resonant frequency of the first resonant cavity. That is, the changes in the duty cycle and switching frequency of the target switch in the first resonant cavity occur simultaneously. For example, if the controller of the switched capacitor converter controls the n resonant cavities to operate in each switching cycle of each first time period, within a certain first time period, the switching frequency f of the target switch in the first resonant cavity of the n resonant cavities decreases from f... i Change to f i+1 (f i The frequency f is less than or equal to the initial frequency corresponding to the first resonant cavity. i Greater than f i+1 f i+1 (greater than or equal to the resonant frequency of the first resonant cavity), the duty cycle D of the target switch in the first resonant cavity can be obtained from D. i Change to D i+1 (D i D is greater than or equal to the initial duty cycle corresponding to the first resonant cavity. i Less than D i+1 D i+1 (Less than or equal to a preset duty cycle). Optionally, in n consecutive first time periods, if the controller controls one of the resonant cavities from the first to the nth resonant cavity to operate sequentially based on the drive signals of each resonant cavity from the first to the nth resonant cavity, the switching frequency and duty cycle of the target switch in the first resonant cavity can also change when the first resonant cavity operates in any first time period. That is to say, the event of simultaneous changes in the duty cycle and switching frequency of the target switch in the first resonant cavity can be applied to various situations mentioned in the above embodiments, and this application does not limit it. In this application, the changes in the duty cycle and switching frequency of the target switch in any of the n resonant cavities can occur simultaneously. In this way, while suppressing the surge current during the startup phase, the time required for the duty cycle and switching frequency of the target switch in each resonant cavity to reach the steady-state value can be shortened, ensuring that the switched capacitor converter can transition from the startup phase to the steady state as quickly as possible.

[0046] Optionally, in some feasible implementations, any one of the n resonant cavities is referred to as the first resonant cavity. After the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity can decrease from the initial frequency to the resonant frequency of the first resonant cavity; or, after the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity can increase from the initial duty cycle to the preset duty cycle. That is to say, the changes in the duty cycle and switching frequency of the target switch in the first resonant cavity are performed sequentially and separately. For example, in a switched-capacitor converter where the controller controls n resonant cavities to operate in each switching cycle of each first time period, during the first k first time periods, the switching frequency f of the target switch in the first resonant cavity of the n resonant cavities first changes from the initial frequency to the resonant frequency of the first resonant cavity, and the duty cycle D of the target switch can remain unchanged from the initial duty cycle; after the switching frequency f of the target switch in the first resonant cavity reaches the resonant frequency of the first resonant cavity, the duty cycle D of the target switch in the first resonant cavity can change from the initial duty cycle to the preset duty cycle, and the switching frequency of the target switch remains at the resonant frequency of the first resonant cavity. Alternatively, during the first k time periods, the duty cycle D of the target switch in the first resonant cavity can first change from the initial duty cycle corresponding to the first resonant cavity to a preset duty cycle, while the switching frequency of the target switch remains at the initial frequency corresponding to the first resonant cavity. After the duty cycle D of the target switch in the first resonant cavity reaches the preset duty cycle, the switching frequency f of the target switch in the first resonant cavity changes from the initial frequency corresponding to the first resonant cavity to the resonant frequency of the first resonant cavity, while the duty cycle D of the target switch remains at the preset duty cycle. Optionally, the change of the duty cycle and switching frequency of the target switch in the first resonant cavity can be performed sequentially. This event can be applied to other situations mentioned in the above embodiments, and this application does not limit it. In this application, the change of the duty cycle and switching frequency of the target switch in any one of the n resonant cavities can be performed sequentially. In this way, while suppressing the surge current during the startup phase, the complexity of the control timing can be reduced, the flexibility of the scheme can be increased, and the applicability is high.

[0047] In some feasible implementations, the switched capacitor converter described above may further include n first resistors, one of which is connected in parallel with one of the n second capacitors. For example... Figure 5As shown, the n first resistors are R1 to Rn. Each of these n first resistors has the same resistance value. The controller in the switched-capacitor converter can be used to ensure that the input voltage Vin provided by the DC power supply is evenly divided by the n series-connected second capacitors when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are off. Then, based on the drive signal of each of the n resonant cavities, the controller controls the switches in each resonant cavity to turn on or off. Furthermore, the initial frequencies corresponding to the drive signals of each of the n resonant cavities are equal. Here, before the controller of the switched-capacitor converter starts operating any resonant cavity, the first resistors connected in parallel with each of the n second capacitors ensure that the input voltage is evenly divided by the n second capacitors. This creates the necessary conditions for even current distribution in each resonant cavity during the startup and steady-state process of the switched-capacitor converter.

[0048] In some feasible implementations, each of the n resonant cavities includes at least one resonant capacitor in its resonant element. When the switched-capacitor converter starts up, the n second capacitors uniformly divide the input voltage, and the controller operates each of the n resonant cavities in each switching cycle of each first time period based on its respective drive signal. The controller can also be used to generate drive signals for each resonant cavity based on the duty cycle of the target switch in each of the n resonant cavities. The drive signals for each resonant cavity are used to control the switching on or off of the switches in each resonant cavity so that the current through the resonant capacitors in the n resonant cavities is equal. It can be understood that the initial frequencies corresponding to the drive signals of each resonant cavity are equal, and the frequency change rate is consistent, therefore the switching frequency of the target switch in each resonant cavity is always the same. When generating drive signals for each resonant cavity based on the switching frequency and duty cycle of the target switch in each resonant cavity, the difference in the drive signals of each resonant cavity is mainly related to the duty cycle of the target switch in each resonant cavity. The duty cycle of the target switch in each of the above resonant cavities increases from the initial duty cycle to the preset duty cycle by a target step size. Among the n initial duty cycles corresponding to the drive signals of each of the above resonant cavities, at least two initial duty cycles are different; for example, ... Figure 3The initial duty cycles corresponding to the driving signals of each of the resonant cavities 1 to n-1 shown can all be equal, while the initial duty cycle corresponding to the driving signal of resonant cavity n is greater than the initial duty cycle corresponding to the driving signal of any one of the resonant cavities 1 to n-1. Optionally, the initial duty cycles corresponding to the driving signals of the 1st to nth resonant cavities can be successively increased by n values; or, the initial duty cycles corresponding to the driving signals of the 1st to kth (2≤k<n)th resonant cavities are all equal, and the initial duty cycles corresponding to the driving signals of the (k+1)th to nth resonant cavities are successively increased by (nk) values, etc., and this application does not impose any restrictions on this. The target step size corresponding to the driving signals of each of the above resonant cavities is obtained based on the initial duty cycle corresponding to the driving signals of each of the above resonant cavities. Specifically, the target step size can be obtained based on the difference between the preset duty cycle and the initial duty cycle corresponding to the driving signal of the resonant cavity, and the longest time limit for the switched capacitor converter to reach steady state from startup. Figure 3 As shown, by differentiating the initial duty cycle of the driving signal of each of the n resonant cavities when the switched capacitor converter starts up, and by differentiating the target step size of the driving signal of each resonant cavity, the voltage difference between the second capacitor connected to each resonant cavity and the resonant capacitor in the resonant cavity can be made as consistent as possible, thereby achieving the purpose of equalizing the current flowing through the resonant capacitor in each resonant cavity.

[0049] In this application, when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities of the switched-capacitor converter are turned off, the controller controls the switching of each resonant cavity to be turned on or off based on the drive signal of each of the n resonant cavities. The drive signal of any one of the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity. As the number of times the target switch in the resonant cavity is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity, and the duty cycle of the target switch increases from the initial duty cycle to a preset duty cycle. That is, when the switched-capacitor converter starts up, an initial drive signal is obtained based on the relatively high initial frequency and small duty cycle of the target switch in each resonant cavity to control each resonant cavity to start working. Gradually, based on the decreasing switching frequency and increasing duty cycle of the target switch to the steady-state frequency (i.e., the resonant frequency) and duty cycle (i.e., the preset duty cycle), a real-time drive signal is obtained to control the operation of each resonant cavity, realizing the transition from startup to steady state. In this process, the change in the switching frequency and duty cycle of the target switch can shorten the single conduction time of the switch in each resonant cavity within each switching cycle, thereby limiting the inrush current. This application does not require an additional current limiting circuit, which can reduce circuit cost and complexity, improve circuit efficiency, and has high applicability. In addition, this application can also use the first resistor to make the n second capacitors evenly divide the input voltage, and by differentiating the initial duty cycle corresponding to the drive signal of the n resonant cavities and the target step size used to represent the duty cycle change rate, it can make the current flowing through the resonant capacitor in each resonant cavity during the startup phase as even as possible.

[0050] Please see Figure 6 , Figure 6 This is a schematic flowchart illustrating the surge current suppression method for a switched-capacitor converter provided in this application. The surge current suppression method provided in this application is applicable to the controller in a switched-capacitor converter, which further includes a first capacitor, n resonant cavities, and n second capacitors connected in series. The first capacitor is connected in series with the n second capacitors. One of the n resonant cavities is connected across the first capacitor and one of the n second capacitors. Each resonant cavity includes at least two sets of switches connected in parallel and a resonant unit connected between the two sets of switches. n is a positive integer greater than 1. The structure of this switched-capacitor converter can be as follows: Figures 2-5 As shown, applied to, for example Figure 1 The application scenario is shown. This method includes, but is not limited to, the following steps:

[0051] Step S601: The controller obtains the driving signal for each resonant cavity based on the switching frequency and duty cycle of the target switch in each of the n resonant cavities.

[0052] Specifically, step S601 is performed when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are turned off (i.e., during startup). The structure of this switched-capacitor converter can be as follows: Figure 3 As shown, the target switch in each resonant cavity is related to the driving signal of each switch in that resonant cavity. Specifically, when the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate waves symmetrically, the duty cycles of the two switches forming the upper bridge arm and the two switches forming the lower bridge arm are always equal, and the phase difference between the driving signal corresponding to the upper bridge arm and the driving signal corresponding to the lower bridge arm is 180 degrees. Here, the target switch can include the four switches forming the upper and lower bridge arms. When the two switches forming the upper bridge arm and the two switches forming the lower bridge arm of each resonant cavity generate waves complementaryly, the duty cycles of the two switches forming the upper bridge arm and the two switches forming the lower bridge arm are complementary. The target switch can include the two switches forming the upper bridge arm. The switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from the initial duty cycle to the preset duty cycle as the number of times the target switch is turned on increases. The preset duty cycle can be the duty cycle reached by the target switch when the switched capacitor converter is operating in steady state. In this application, when the switched capacitor converter starts up, the drive signal of each resonant cavity is obtained based on the larger switching frequency and smaller duty cycle of the target switch to control the operation of each resonant cavity, thereby suppressing the surge current during the startup process.

[0053] In one feasible implementation, the changes in the switching frequency and duty cycle of the target switches in each resonant cavity can occur simultaneously or sequentially. If, during the process of the duty cycle of the target switch in the first resonant cavity (any one of the n resonant cavities) increasing from the initial duty cycle to the aforementioned preset duty cycle, the switching frequency of the target switch in the first resonant cavity can decrease from the initial frequency to the resonant frequency of the first resonant cavity, this can suppress surge current during the startup phase of the switched-capacitor converter while shortening the time required for both the duty cycle and switching frequency of the target switches in each resonant cavity to reach steady-state values, ensuring that the switched-capacitor converter can transition from the startup phase to steady state as quickly as possible. If the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity can decrease from the initial frequency to the resonant frequency of the first resonant cavity; or, if the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity can increase from the initial duty cycle to the preset duty cycle. This can suppress surge current during the startup phase while reducing the complexity of the control timing, increasing the flexibility of the scheme, and making it highly applicable.

[0054] In step S602, during at least one first time period, the controller controls the switching on or off of the switch in the at least one resonant cavity based on the drive signal of at least one resonant cavity among the n resonant cavities.

[0055] The first time period includes at least one switching cycle. One switching cycle is defined as the period from the k-th turn-on time of the target switch in each of the resonant cavities to the (k+1)-th turn-on time of the target switch, where k is a positive integer. Within the switching cycle of the first time period, the controller can control the switching on or off of at least one switch in at least one resonant cavity. Here, at least one resonant cavity can include one resonant cavity, m (1≤m≤n) resonant cavities, or n resonant cavities, etc.

[0056] In one feasible implementation, the controller can be used to control the switching on or off of the switches in each of the n resonant cavities based on the drive signals of each resonant cavity in each switching cycle of the first time period. The phase difference between the drive signals of two adjacent resonant cavities is 360 / n degrees. During each switching cycle from startup to reaching steady state, the controller controls the n resonant cavities to operate in out-of-phase mode based on the drive signals of each resonant cavity. The switching frequency of the target switch corresponding to each drive signal gradually decreases, and the duty cycle of the target switch gradually increases, thereby achieving direct suppression of surge current.

[0057] Optionally, in one feasible implementation, the controller can be used to sequentially control the switching on or off of a switch in one of the resonant cavities from the first to the mth resonant cavities within m consecutive first time periods, based on the drive signals of each resonant cavity from the first to the mth resonant cavities, where m is an integer greater than 1 and less than or equal to n. In this application, during multiple consecutive first time periods from startup to reaching steady state, the controller gradually controls the operation of one of the n resonant cavities based on the drive signals of each resonant cavity, causing the switched-capacitor converter to gradually transition to a steady state, thereby achieving direct suppression of surge current.

[0058] Optionally, in one feasible implementation, the controller can be used to: control the switching on or off of m consecutive resonant cavities from the first to the nth resonant cavity successively, based on the drive signals of each resonant cavity from the first to the nth resonant cavity, within n / m consecutive first time periods. Wherein, the phase difference between the drive signals of two adjacent resonant cavities in the m resonant cavities is 360 / m degrees, m is greater than or equal to 2, and n is a multiple of m. The two consecutive first time periods correspond to different sets of m resonant cavities. During multiple consecutive first time periods from startup to reaching steady state, the controller gradually controls the operation of m consecutive resonant cavities in the n resonant cavities based on the drive signals of each resonant cavity, causing the switched capacitor converter to gradually transition to steady state, thereby achieving direct suppression of surge current. In addition, during the initial time period of the startup process, m resonant cavities are working, which can shorten the time it takes for the switching frequency and duty cycle of each target switch in n resonant cavities to change to the steady-state value, ensuring that the switched capacitor converter reaches the steady state as soon as possible.

[0059] Optionally, in one feasible implementation, the controller can be used to: control the switching on or off of the switches in each of the first to m resonant cavities respectively, based on the drive signals of the first to m resonant cavities, during the kth first time period of the two or more first time periods; wherein the phase difference between the drive signals of two adjacent resonant cavities in the first to m resonant cavities is 360 / m degrees, m is greater than or equal to 2 and less than or equal to n, k is a positive integer, and m increases as k increases. That is, during the multiple first time periods from startup to reaching steady state, the controller gradually controls more resonant cavities to join other resonant cavities to work together, based on the drive signals of each resonant cavity in the n resonant cavities. The initial frequency and initial duty cycle of the drive signal of the newly added resonant cavity are different from the initial frequency and initial duty cycle of the drive signal of the previously working resonant cavity. In this way, the switched capacitor converter can transition to steady state as quickly as possible, achieving direct suppression of surge current.

[0060] In one feasible implementation, n first resistors can be used to make n second capacitors uniformly divide the input voltage, and the frequency of the target switch in the drive signal of each of the n resonant cavities can be controlled to always be equal. Furthermore, the initial duty cycle and target step size corresponding to the drive signal of each resonant cavity can be set differently, and the switching in each of the n resonant cavities can be controlled to turn on or off after obtaining the drive signal. Specifically, at least two of the n initial duty cycles corresponding to the drive signals of each resonant cavity can be different, achieving differentiated setting of the n initial duty cycles. The target step size corresponding to the drive signal of each resonant cavity is obtained based on the initial duty cycle corresponding to the drive signal of each resonant cavity. Specifically, the target step size can be obtained based on the difference between the preset duty cycle and the initial duty cycle corresponding to the drive signal of the resonant cavity, and the longest time limit for the switched capacitor converter to reach steady state from startup. In this way, by differentiating the initial duty cycle of the driving signal of each of the n resonant cavities when the switched capacitor converter starts up, and by differentiating the target step size of the driving signal of each resonant cavity, the voltage difference between the second capacitor connected to each resonant cavity and the resonant capacitor in the resonant cavity can be made as consistent as possible, thereby achieving the purpose of equalizing the current flowing through the resonant capacitor in each resonant cavity.

[0061] In this application, when the switched-capacitor converter is connected to a DC power supply and all switches in the n resonant cavities of the switched-capacitor converter are turned off, the controller controls the switching of each resonant cavity to be turned on or off based on the drive signal of each of the n resonant cavities. The drive signal of any one of the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in that resonant cavity. As the number of times the target switch in the resonant cavity is turned on increases, the switching frequency of the target switch decreases from the initial frequency to the resonant frequency of the resonant cavity, and the duty cycle of the target switch increases from the initial duty cycle to a preset duty cycle. That is, when the switched-capacitor converter starts up, an initial drive signal is obtained based on the relatively high initial frequency and small duty cycle of the target switch in each resonant cavity to control each resonant cavity to start working. Gradually, based on the decreasing switching frequency and increasing duty cycle of the target switch to the steady-state frequency (i.e., the resonant frequency) and duty cycle (i.e., the preset duty cycle), a real-time drive signal is obtained to control the operation of each resonant cavity, realizing the transition from startup to steady state. In this process, changes in the switching frequency and duty cycle of the target switch can shorten the single conduction time of the switch in each resonant cavity within each switching cycle, thereby limiting the inrush current. This application eliminates the need for additional current-limiting circuits, directly suppressing inrush current through software control strategies. This reduces circuit cost and complexity, improves circuit efficiency, and offers high applicability. Furthermore, this application can utilize a first resistor to evenly divide the input voltage across n second capacitors, and by differentially setting the initial duty cycle corresponding to the drive signals of the n resonant cavities and the target step size representing the duty cycle change rate, it can ensure that the current flowing through the resonant capacitors in each resonant cavity is as evenly distributed as possible during the startup phase.

Claims

1. A switched-capacitor converter, characterized in that, The switched-capacitor converter includes a controller, a first capacitor, n resonant cavities, and n second capacitors connected in series. The n second capacitors are connected in series between the input and output terminals of the switched-capacitor converter. The first capacitor is connected in series with the n second capacitors. One of the n resonant cavities is connected across the first capacitor and one of the n second capacitors. The second capacitor connected to the input terminal is the first second capacitor, and the second capacitor connected to the output terminal is the nth second capacitor. The input terminal of the ith resonant cavity is connected in parallel across the ith second capacitor. Each resonant cavity includes at least two sets of switches connected in parallel and a resonant unit connected between the two sets of switches. n is a positive integer greater than 1. The controller is used to control the switching of the switches in each of the n resonant cavities to the on or off based on the driving signal of each of the n resonant cavities when the switched capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are off, so as to suppress surge current. The driving signal of the first resonant cavity in the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in the first resonant cavity. The switching frequency of the target switch decreases from an initial frequency to the resonant frequency of the first resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from an initial duty cycle to a preset duty cycle as the number of times the target switch is turned on increases. The first resonant cavity is any one of the n resonant cavities. In the process of controlling the switching on or off of the switches in each of the n resonant cavities based on the driving signals of each resonant cavity, the controller is used to: During at least one first time period, the switching of a switch in the at least one resonant cavity is controlled to be turned on or off based on the driving signal of at least one resonant cavity among the n resonant cavities. The switching frequency of the target switch in any one of the at least one resonant cavity is greater than or equal to the resonant frequency of the resonant cavity, and the duty cycle of the target switch is less than or equal to the preset duty cycle. The first time period includes at least one switching cycle. The period from the kth turn-on time of the target switch in each resonant cavity to the (k+1)th turn-on time of the target switch is one switching cycle, where k is a positive integer.

2. The switched capacitor converter according to claim 1, characterized in that, The at least one resonant cavity is one of the n resonant cavities, and the controller is used for: During each switching cycle of the first time period, the switching in each of the n resonant cavities is turned on or off based on the driving signal of each resonant cavity. The phase difference between the driving signals of two adjacent resonant cavities in the n resonant cavities is 360 / n degrees.

3. The switched capacitor converter according to claim 1, characterized in that, The controller is used for: During m consecutive first time periods, based on the driving signals of each resonator from the first resonator to the mth resonator, the switch in one of the resonators from the first resonator to the mth resonator is turned on or off sequentially, where m is an integer greater than 1 and less than or equal to n.

4. The switched capacitor converter according to claim 1, characterized in that, The controller is used for: Within a continuous n / m first time period, based on the driving signals of each resonator from the first resonator to the nth resonator, the switching on or off of m consecutive resonators from the first resonator to the nth resonator is controlled sequentially. The phase difference between the driving signals of two adjacent resonators in the m resonators is 360 / m degrees, where m is greater than or equal to 2 and n is a multiple of m. The two sets of m resonators corresponding to the two consecutive first time periods are different.

5. The switched capacitor converter according to claim 1, characterized in that, The at least one first time period includes two or more first time periods, and the controller is used to: In the kth first time period of the two or more first time periods, based on the driving signals of the first to the mth resonant cavities, the switches in each of the first to the mth resonant cavities are controlled to be turned on or off respectively. The phase difference between the driving signals of two adjacent resonant cavities in the first to the mth resonant cavities is 360 / m degrees, where m is greater than or equal to 2 and less than or equal to n, k is a positive integer, and m increases as k increases.

6. The switched capacitor converter according to any one of claims 1-5, characterized in that, As the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity.

7. The switched capacitor converter according to any one of claims 1-5, characterized in that, After the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity. Alternatively, after the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle.

8. The switched capacitor converter according to claim 2, characterized in that, The switched capacitor converter further includes n first resistors, one of the n first resistors is connected in parallel with one of the n second capacitors, and the initial frequencies corresponding to the driving signals of each of the n resonant cavities are equal.

9. The switched capacitor converter according to claim 8, characterized in that, The resonant unit in each of the n resonant cavities includes at least one resonant capacitor, and the controller is further configured to: The drive signal for each resonant cavity is generated based on the duty cycle of the target switch in each of the n resonant cavities; the drive signal for each resonant cavity is used to control the switching on or off in each resonant cavity so that the current through the resonant capacitor in each of the n resonant cavities is equal, and the duty cycle of the target switch in each resonant cavity increases from the initial duty cycle to the preset duty cycle according to the target step size; Among the n initial duty cycles corresponding to the driving signals of each resonator, at least two initial duty cycles are different, and the target step size corresponding to the driving signals of each resonator is obtained based on the initial duty cycle corresponding to the driving signals of each resonator.

10. A method for suppressing surge current in a switched-capacitor converter, characterized in that, A controller is applied in a switched-capacitor converter, the switched-capacitor converter further comprising a first capacitor, n resonant cavities, and n second capacitors connected in series; the n second capacitors are connected in series between the input and output terminals of the switched-capacitor converter, the first capacitor is connected in series with the n second capacitors, one of the n resonant cavities is connected across the first capacitor and one of the n second capacitors, wherein the second capacitor connected to the input terminal is the first second capacitor, the second capacitor connected to the output terminal is the nth second capacitor, the input terminal of the ith resonant cavity is connected in parallel across the ith second capacitor, each resonant cavity includes at least two sets of switches connected in parallel and a resonant unit connected between the two sets of switches, where n is a positive integer greater than 1; the method includes: When the switched capacitor converter is connected to a DC power supply and all switches in the n resonant cavities are turned off, the switching in each resonant cavity is controlled to turn on or off based on the driving signal of each of the n resonant cavities to suppress surge current. The driving signal of the first resonant cavity among the n resonant cavities is obtained based on the switching frequency and duty cycle of the target switch in the first resonant cavity. The switching frequency of the target switch decreases from an initial frequency to the resonant frequency of the first resonant cavity as the number of times the target switch is turned on increases, and the duty cycle of the target switch increases from an initial duty cycle to a preset duty cycle as the number of times the target switch is turned on increases. The first resonant cavity is any one of the n resonant cavities. The step of controlling the switching on or off of the switches in each of the n resonant cavities based on the driving signal of each resonant cavity includes: During at least one first time period, the switching of a switch in the at least one resonant cavity is controlled to be turned on or off based on the driving signal of at least one resonant cavity among the n resonant cavities. The switching frequency of the target switch in any one of the at least one resonant cavity is greater than or equal to the resonant frequency of the resonant cavity, and the duty cycle of the target switch is less than or equal to the preset duty cycle. The first time period includes at least one switching cycle. The period from the kth turn-on time of the target switch in each resonant cavity to the k+11th turn-on time of the target switch is one switching cycle, where k is a positive integer.

11. The method according to claim 10, characterized in that, The at least one resonant cavity is one of the n resonant cavities, and the step of controlling the switching on or off of the at least one resonant cavity based on the driving signal of at least one of the n resonant cavities during at least one first time period includes: During each switching cycle of the first time period, the switching in each of the n resonant cavities is turned on or off based on the driving signal of each resonant cavity. The phase difference between the driving signals of two adjacent resonant cavities in the n resonant cavities is 360 / n degrees.

12. The method according to claim 10, characterized in that, The step of controlling the switching on or off of a switch in at least one of the n resonant cavities based on the driving signal of at least one of the n resonant cavities during at least one first time period includes: During m consecutive first time periods, based on the driving signals of each resonator from the first resonator to the mth resonator, the switch in one of the resonators from the first resonator to the mth resonator is turned on or off sequentially, where m is an integer greater than 1 and less than or equal to n.

13. The method according to claim 10, characterized in that, The step of controlling the switching on or off of a switch in at least one of the n resonant cavities based on the driving signal of at least one of the n resonant cavities during at least one first time period includes: Within a continuous n / m first time period, based on the driving signals of each resonator from the first resonator to the nth resonator, the switching on or off of m consecutive resonators from the first resonator to the nth resonator is controlled sequentially. The phase difference between the driving signals of two adjacent resonators in the m resonators is 360 / m degrees, where m is greater than or equal to 2 and n is a multiple of m. The two sets of m resonators corresponding to the two consecutive first time periods are different.

14. The method according to claim 10, characterized in that, The at least one first time period includes two or more first time periods, and the step of controlling the switching on or off of the switch in the at least one resonant cavity based on the driving signal of at least one resonant cavity among the n resonant cavities within the at least one first time period includes: In the kth first time period of the two or more first time periods, based on the driving signals of the first to the mth resonant cavities, the switches in each of the first to the mth resonant cavities are controlled to be turned on or off respectively. The phase difference between the driving signals of two adjacent resonant cavities in the first to the mth resonant cavities is 360 / m degrees, where m is greater than or equal to 2 and less than or equal to n, k is a positive integer, and m increases as k increases.

15. The method according to any one of claims 10-14, characterized in that, As the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity.

16. The method according to any one of claims 10-14, characterized in that, After the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle, the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity. Alternatively, after the switching frequency of the target switch in the first resonant cavity decreases from the initial frequency to the resonant frequency of the first resonant cavity, the duty cycle of the target switch in the first resonant cavity increases from the initial duty cycle to the preset duty cycle.

17. The method according to claim 11, characterized in that, The switched capacitor converter further includes n first resistors, one of the n first resistors is connected in parallel with one of the n second capacitors, and the initial frequencies corresponding to the driving signals of each of the n resonant cavities are equal.

18. The method according to claim 17, characterized in that, The resonant unit in each of the n resonant cavities includes at least one resonant capacitor. Before controlling the switching on or off of the switches in each of the n resonant cavities based on the driving signal of each resonant cavity, the method further includes: The drive signal for each of the n resonant cavities is generated based on the duty cycle of the target switch in each resonant cavity. The drive signal for each resonant cavity is used to control the switching on or off in each resonant cavity so that the current through the resonant capacitor in each of the n resonant cavities is equal. The duty cycle of the target switch in each resonant cavity increases from the initial duty cycle to the preset duty cycle by a target step size. At least two of the n initial duty cycles corresponding to the drive signal of each resonant cavity are different. The target step size corresponding to the drive signal of each resonant cavity is obtained based on the initial duty cycle corresponding to the drive signal of each resonant cavity.

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