A staggered parallel resonant converter, control method, device and medium thereof

Abstract

The application discloses an interleaved parallel resonant converter and a control method, equipment and medium thereof, relates to the field of resonant converters, and determines the average value of the primary side resonant current of each branch in the interleaved parallel resonant converter, then determines the corresponding phase shift control amount of the branch according to the size relationship between the resonant current and the average value of the branch, adjusts the driving signal of the secondary side circuit in the branch based on the obtained phase shift control amount, adjusts the output current of the branch by using the phase shift control process, and finally achieves the current balance of the branches. In the case that there are differences in hardware parameters such as component parameters between the branches, the current balance control of the branches is realized, so that the frequency of the driving signals of the branches is consistent, the output currents of the branches are effectively balanced, the ripple of the output current of the whole resonant converter is reduced, and the performance of the resonant converter is ensured.

Description

Technical Field

[0001] This invention relates to the field of resonant converters, and in particular to an interleaved parallel resonant converter and its control method, device and medium. Background Technology

[0002] Resonant converters are widely used in communication and server power supplies, brick-type power supplies, micro-inverters, DC / DC converters for charging piles, and bidirectional DC / DC converters for residential and commercial applications. Resonant converters using a single resonant unit are common in low-to-medium power applications. However, when the capacity of the resonant converter needs to be increased or the power level of the application needs to be higher, continuing to use a single resonant unit would require increasing the inductance of the magnetizing inductor and the resonant inductor, which would severely affect the power density of the resonant converter. Therefore, interleaved parallel resonant converters, including multiple resonant units, have emerged. Interleaved parallel resonant converters utilize multiple interleaved parallel resonant units to achieve efficient energy transfer. The frequency of the drive signal for each branch of each resonant unit remains consistent, allowing each branch to stably and evenly share the total power, thereby achieving power superposition to meet the needs of high-power applications and realizing a high-efficiency, high-power-density resonant converter at higher power levels.

[0003] However, in practical applications, when the control system of a resonant converter uses the same frequency drive signal to drive different branches, slight differences in component parameters between the branches can lead to variations in the actual output current of each branch. This current imbalance can affect the normal frequency closed-loop control of each branch, resulting in inconsistencies in their frequencies. Furthermore, it prevents the resonant converter from forming a stable, interleaved, coherent pulsating DC current on the output side, significantly increasing high-frequency ripple in the output current and degrading the converter's performance. Therefore, avoiding inconsistencies in the output current of different branches in an interleaved parallel resonant converter has become an urgent technical problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide an interleaved parallel resonant converter and its control method, device and medium, which aims to solve the technical problem of inconsistent output current in different branches of the interleaved parallel resonant converter.

[0005] To solve the above-mentioned technical problems, the present invention provides a control method for an interleaved parallel resonant converter, comprising: Determine the average value of the resonant current in each branch of the interleaved parallel resonant converter; For any branch, the phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value. The driving signal of the secondary circuit in the branch is adjusted based on the phase shift control amount to achieve current balance in each branch.

[0006] Optionally, the control method for the interleaved parallel resonant converter also includes: The safe range of the phase shift control quantity is determined according to preset constraints; the preset constraints include one or more combinations of the following: the switching transistors in the primary circuit of each branch can achieve zero-voltage conduction, the conversion efficiency of each branch is greater than or equal to a first preset value, and the voltage stress across the switching transistors in each branch is less than or equal to a second preset value. The upper and lower limits of the phase shift control quantity are defined based on the safety interval; the upper limit is less than or equal to the upper limit of the safety interval, and the lower limit is greater than or equal to the lower limit of the safety interval.

[0007] Optionally, before determining the average value of the resonant current in each branch of the interleaved parallel resonant converter, the method further includes: Determine whether the frequencies of each branch in an interleaved parallel resonant converter have reached a steady state. If so, proceed to the step of determining the average value of the resonant current of each branch in the interleaved parallel resonant converter; If not, then jump back to the step of determining whether the frequency of each branch in the interleaved parallel resonant converter has reached a steady state.

[0008] Optionally, determining the phase-shift control amount corresponding to the branch based on the relationship between the resonant current of the branch and the average value includes: If the resonant current of the branch is less than the average value, then calculate the difference between the average value and the resonant current of the branch. Determine the phase shift control quantity corresponding to the difference; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: The driving signal of the secondary circuit in the control branch lags behind the driving signal of the primary circuit in the control branch by the phase shift control amount.

[0009] Optionally, determining the phase-shift control amount corresponding to the branch based on the relationship between the resonant current of the branch and the average value includes: If the resonant current of the branch is greater than the average value, then the phase shift control quantity is set to 0; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: The drive signal of the secondary circuit in the control branch is kept synchronized with the drive signal of the primary circuit in the control branch.

[0010] Optionally, the interleaved parallel resonant converter includes two branches; The phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value, including: Determine the current difference between the average value and the first resonant current; the first resonant current is the resonant current of the primary circuit in the first branch; The phase shift control quantity is determined based on the current difference; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: If the current difference is greater than zero, it is determined that the first resonant current is less than the average value, and the driving signal of the secondary circuit in the first branch is controlled to lag behind the phase shift control amount relative to the driving signal of the primary circuit in the first branch, and the driving signal of the secondary circuit in the second branch is controlled to remain synchronized with the driving signal of the primary circuit in the second branch. If the current difference is less than zero, it is determined that the first resonant current is greater than the average value, and the driving signal of the secondary circuit in the second branch is controlled to lag behind the driving signal of the primary circuit in the second branch by the phase shift control amount, and the driving signal of the secondary circuit in the second branch is controlled to remain synchronized with the driving signal of the primary circuit in the second branch. If the current difference is zero, it is determined that the resonant currents of the two branches are balanced, and the process jumps back to the step of determining the average value of the resonant currents of each branch in the interleaved parallel resonant converter.

[0011] Optionally, determining the phase shift control amount corresponding to the difference includes: Determine the phase shift angle corresponding to the difference; the magnitude of the phase shift angle is positively correlated with the difference. Calculate the ratio between the phase shift angle and the reference value to obtain the per-unit value of the phase shift angle relative to the reference value; the reference value is the angle value corresponding to one complete cycle of the drive signal; The product of the per-unit value and the signal period is determined as the phase-shift control quantity.

[0012] To address the aforementioned technical problems, the present invention also provides an electronic device, comprising: Memory, used to store computer programs; A processor for implementing the steps of the control method for the interleaved parallel resonant converter as described above.

[0013] To address the aforementioned technical problems, the present invention also provides an interleaved parallel resonant converter, comprising the electronic device as described above and M branches, wherein the M branches are connected in parallel, and the electronic device is connected to the driving terminal of each branch; M is a positive integer greater than 1.

[0014] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the control method for the interleaved parallel resonant converter as described above.

[0015] This invention provides a control method for an interleaved parallel resonant converter. It determines the average value of the primary-side resonant current of each branch in the interleaved parallel resonant converter. Then, for any branch, it determines the corresponding phase-shift control quantity based on the relationship between its resonant current and the average value. Based on the obtained phase-shift control quantity, it adjusts the drive signal of the secondary circuit in the branch, using the phase-shift control process to adjust the output current of that branch, ultimately achieving current balance across all branches. Even when there are differences in hardware parameters such as component parameters between branches, this method achieves current sharing control for each branch, ensuring consistent drive signal frequencies and effectively guaranteeing output current balance. This reduces the ripple of the overall resonant converter's output current, ensuring the converter's performance.

[0016] The present invention also provides an electronic device, an interleaved parallel resonant converter, and a computer-readable storage medium, which have the same beneficial effects as the control method of the interleaved parallel resonant converter described above. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a control method for an interleaved parallel resonant converter provided by the present invention; Figure 2 A schematic diagram of an interleaved parallel resonant converter provided by the present invention; Figure 3 A schematic diagram of the driving signal waveform during the operation of an interleaved parallel resonant converter provided by the present invention; Figure 4 A schematic diagram illustrating the current sharing control process during the operation of an interleaved parallel resonant converter provided by the present invention; Figure 5 This is a schematic diagram of the structure of an electronic device provided by the present invention. Detailed Implementation

[0019] The core of this invention is to provide an interleaved parallel resonant converter and its control method, device and medium, so as to realize the current sharing control of each branch, thereby ensuring the frequency consistency of the driving signal of each branch, and effectively ensuring the balance of the output current of each branch, thereby reducing the ripple of the output current of the entire resonant converter and ensuring the performance of the resonant converter.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] See Figure 1 As shown, Figure 1 A flowchart illustrating a control method for an interleaved parallel resonant converter provided by the present invention; to solve the above-mentioned technical problems, the present invention provides a control method for an interleaved parallel resonant converter, comprising: S11: Determine the average value of the resonant current of each branch in the interleaved parallel resonant converter; S12: For any branch, determine the corresponding phase shift control quantity based on the relationship between the resonant current and the average value of the branch; S13: Adjust the drive signal of the secondary circuit in the branch based on the phase shift control quantity to achieve current balance in each branch.

[0022] It is easy to understand that, in order to achieve current sharing control of the output current of each branch in an interleaved parallel resonant converter, this application starts from the resonant current of each branch and performs current sharing control on the resonant current of each branch, thereby achieving current sharing control of the output current. To ensure the balance of the resonant current of each branch, the average value of the resonant current of each branch is first determined. Then, based on this average value, the drive signal of the secondary circuit in each branch is phase-shifted. By adjusting the phase shift of the drive signal, the output current gain of the branch is adjusted, thereby achieving the balance between the resonant current and the output current of each branch.

[0023] It should be noted that the phase-shift control quantity used in phase-shift control is related to the relationship between the resonant current and the average value of the branch. This allows the phase-shift control to adjust the resonant current in the direction of the average value change, so that the resonant current of all branches is close to or basically consistent with the average value, thereby achieving current balance among the branches, i.e., current sharing control. Current balance refers to the resonant current (or output current) of each branch remaining consistent or basically consistent. This application does not make any special restrictions on the specific value of the phase-shift control quantity or the specific implementation method of phase-shift control. It can be that after determining the average value each time, all branches are controlled separately based on the average value, or after determining the average value each time, one or a part of the branches are selected for phase-shift control adjustment, and then the phase-shift control strategy for other branches is updated based on the adjusted and re-determined average value. The phase-shift control process can be implemented by adjusting the phase change of the carrier corresponding to the drive signal. There are multiple choices for determining the phase-shift control quantity, which can be implemented using a current sharing loop based on a PI controller design. The entire current sharing control process can be implemented by directly reusing the control system of the interleaved parallel resonant converter, or it can be implemented independently by setting up a separate controller. For example, a current sharing loop based on a PI controller can be integrated into the control system of the interleaved parallel resonant converter to realize the entire current sharing control process.

[0024] It should be further explained that phase-shift control is implemented based on the normal operation of the interleaved parallel resonant converter. That is, while the control system of the interleaved parallel resonant converter generates drive signals for the primary and secondary circuits based on application requirements and controls the entire interleaved parallel resonant converter to operate normally, phase-shift control is applied to the drive signals of the secondary circuit based on the drive signals generated by the control system. Normal operation of the interleaved parallel resonant converter refers to the process by which the control system generates and outputs drive signals according to application requirements (such as specific power conversion requirements) to control the entire interleaved parallel resonant converter, ensuring that the interleaved parallel resonant converter meets those application requirements. During normal operation, there is a strict and stable phase interleaving relationship between the drive signals of each branch, and the two switches on the same bridge arm conduct alternately (i.e., the drive signals are complementary).

[0025] Understandably, to avoid interference with the output of the interleaved parallel resonant converter's control system caused by excessively fast current sharing control, and to prevent output oscillation, the entire current sharing control process in this application adopts a closed-loop control method. When current sharing control is required, the current resonant current of each branch is first collected as feedback value. After all feedback values ​​have been collected, the average value is determined based on the collected feedback values, and then the corresponding phase shift control quantity is determined based on the determined average value. This application does not impose specific limitations on the control frequency of the entire current sharing control process; generally, a control cycle is set. When current sharing control is required, the above steps are periodically executed according to the set control cycle to complete the current sharing control. The control cycle can be set relatively long to slow down the current sharing control speed, generally controlled at the millisecond level. Meanwhile, to avoid circulating current between branches and the impact of phase-shift control on the power supply of the primary circuit of the interleaved parallel resonant converter, this application specifically adopts phase-shift control of the drive signal of the secondary circuit in the branch to achieve current sharing control. When the primary circuit of the interleaved parallel resonant converter adopts a half-bridge topology, current sharing control can also be effectively achieved by adjusting the drive signal of the secondary circuit.

[0026] It should be noted that this application does not impose specific limitations on the interleaved parallel resonant converter and the specific types and implementation methods of its branches. A branch in an interleaved parallel resonant converter refers to an independent power conversion unit with complete resonant conversion function. A branch specifically includes a primary circuit, a resonant network, a transformer, and a secondary circuit connected in series. The primary and secondary circuits are composed of switching transistors. The primary circuit can be a half-bridge or full-bridge topology composed of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The secondary circuit can be a rectifier circuit composed of switching transistors. The resonant network specifically includes a resonant inductor and a resonant capacitor. The drive signal for the secondary circuit is also the drive signal output from the control system of the interleaved parallel resonant converter to the switching transistors of the secondary circuit. Adjusting the drive signal for the secondary circuit is usually a synchronous adjustment of the drive signals for all switching transistors in the secondary circuit. This application does not impose any special restrictions on the method of determining or implementing the average value; it can be implemented using various methods such as arithmetic mean or square mean.

[0027] As one specific embodiment, see Figure 2 As shown, Figure 2 A schematic diagram of an interleaved parallel resonant converter provided by the present invention; Figure 2The diagram shows an interleaved parallel resonant converter with two branches. The primary circuit of the first branch includes power switches S1 and S2, capacitors C1 and C2, a transformer Tr1, and a resonant network consisting of a resonant inductor Lr1, a magnetizing inductor Lm1, and a resonant capacitor Cr1. The secondary circuit of the first branch includes power switches S5, S6, S7, and S8, and a capacitor Co1. The primary circuit of the second branch includes power switches S3 and S4, capacitors C3 and C4, a transformer Tr2, and a resonant network consisting of a resonant inductor Lr2, a magnetizing inductor Lm2, and a resonant capacitor Cr2. The secondary circuit of the second branch includes power switches S9, S10, S11, and S12, and a capacitor Co2. Both transformers have a turns ratio of N:1 (primary side: secondary side); the input and output sides of the two branches are connected in parallel. The input side is connected to the power supply Ug after being connected in parallel, and the output side is connected in parallel to output voltage Uout.

[0028] Further, see Figure 3 As shown, Figure 3 A schematic diagram of the driving signal waveform during the operation of an interleaved parallel resonant converter provided by the present invention; Figure 2 The interleaved parallel resonant converter shown exhibits the following waveforms during operation: the drive signal waveforms of each switch in the primary circuit and each switch in the secondary circuit are as follows. Figure 3 As shown, power switches S1 and S2 form one bridge arm, power switches S3 and S4 form one bridge arm, power switches S5 and S6 form one bridge arm, power switches S7 and S8 form one bridge arm, power switches S9 and S10 form one bridge arm, and power switches S11 and S12 form one bridge arm; there are a total of six bridge arms. For any two power switches in any bridge arm, their corresponding drive signals are complementary.

[0029] Specifically, the driving signals for the primary circuit in the first branch include the driving signals for power switches S1 and S2; the driving signals for the primary circuit in the second branch include the driving signals for power switches S3 and S4; the driving signals for the secondary circuit in the first branch include the driving signals for power switches S5, S6, S7, and S8; and the driving signals for the secondary circuit in the second branch include the driving signals for power switches S9, S10, S11, and S12. The driving signals for the second branch lag behind the driving signals for the first branch by T / 4, where T is one complete cycle of the driving signal, thus achieving interleaved driving between the two branches.

[0030] This application provides a control method for an interleaved parallel resonant converter to achieve current sharing control of each branch. By determining the average resonant current of all branches and using this average as a reference, phase-shift control is applied to the drive signals of the secondary circuits in each branch. This phase-shift control adjusts the branch gain, thereby achieving load balancing among the branches and achieving current sharing control. This automatic control process ensures current balancing of the branches during normal operation of the interleaved parallel resonant converter. This allows for current sharing control even when hardware parameters differ between branches, further reducing the ripple of the output current and lowering the filter parameter requirements for output-side filtering design. Simultaneously, it facilitates the use of PFM (Pulse Frequency Modulation) control in the interleaved parallel resonant converter control system, ensuring consistent drive signal frequencies across branches based on balanced output current. This guarantees accurate interleaved cooperative operation of the branches and avoids circulating current and resonance mismatch between branches caused by frequency differences.

[0031] As an optional embodiment, determining the average value of the resonant current of each branch in the interleaved parallel resonant converter includes: For any branch of the interleaved parallel resonant converter, the resonant current of the primary circuit in the branch is sampled to obtain the resonant current of each branch. Determine the sum of the resonant currents in all branches; Calculate the ratio between the current and the number of branches in the interleaved parallel resonant converter to obtain the average value of the resonant current of each branch.

[0032] Understandably, calculating the average resonant current requires obtaining the resonant current of all branches in the interleaved parallel resonant converter. Therefore, it is necessary to first sample the current of each branch in the interleaved parallel resonant converter to calculate the average value based on the current and the number of branches. To ensure safety, this application selects to sample the resonant current of the primary circuit in each branch for current sharing control. The resonant current of the primary circuit refers to the current flowing through the resonant network of the transformer's primary side. This application does not impose specific limitations on the specific sampling method for the resonant current of the primary circuit in each branch; various methods, such as using current sensors, can be employed.

[0033] As a specific embodiment, such as Figure 2 As shown, during current sharing control, the resonant current i of the primary circuit in the first branch is sampled respectively. r1 The resonant current i in the primary circuit of the second branch r2 Then, the sum of the two resonant currents is used as a feedback signal and input to the current sharing loop. The current sharing loop calculates the average value of the resonant current based on the received current sum. Then, for any branch, the PI controller in the current sharing loop uses the difference between the resonant current of that branch and the average value as the error, and generates phase-shift control quantities for the first branch and the second branch respectively, so that the resonant current of the first branch and / or the second branch is adjusted in the direction of reducing the error until the error is zero (or close to zero), thereby realizing current sharing control.

[0034] Furthermore, considering that the resonant current is typically a high-frequency AC signal, the feedback signal needs to be conditioned before being input into the current sharing loop. For example, when using a current sensor for sampling, the resonant current output by the current sensor can be processed by a rectifier circuit, a low-pass filter circuit, and other circuits for signal conditioning, resulting in a relatively stable DC voltage signal corresponding to the resonant current. Alternatively, the resonant currents output by two current sensors can be input into a signal conditioning circuit. This circuit uses an adder circuit to calculate the average value of the two resonant currents (outputting an average current). The average current is then processed by a rectifier circuit, a low-pass filter circuit, and other circuits for signal conditioning, resulting in a relatively stable DC voltage signal corresponding to the average value. Finally, a voltage divider circuit converts the DC voltage signal output from the signal conditioning circuit into a weak signal (e.g., 0-3.3V), which is then fed into the current sharing loop for current sharing control calculations to obtain the corresponding phase-shift control quantity.

[0035] Specifically, the average value of the resonant current of each branch is determined by detecting the resonant current of the primary circuit. Current sharing control is performed using the resonant current of the higher-voltage primary circuit, which can effectively protect the high-voltage side and ensure the safety and reliability of the current sharing control process. Furthermore, the change of the resonant current of the primary circuit takes precedence over the current of the secondary circuit, so the determination of the average value and the response speed of the entire current sharing control are faster, which can further avoid the impact of electromagnetic coupling delay and signal transmission delay on the control response speed.

[0036] As an optional embodiment, the control method for the interleaved parallel resonant converter further includes: The safe range of the phase shift control quantity is determined according to the preset constraints. The preset constraints include one or more combinations of the following: the switching transistors in the primary circuit of each branch can achieve zero voltage conduction, the conversion efficiency of each branch is greater than or equal to the first preset value, and the voltage stress across the switching transistors in each branch is less than or equal to the second preset value. The upper and lower limits of the phase-shift control quantity are defined based on the safety interval; the upper limit is less than or equal to the upper limit of the safety interval, and the lower limit is greater than or equal to the lower limit of the safety interval.

[0037] It is easy to understand that, in order to ensure the normal operation of the interleaved parallel resonant converter, the phase-shift control quantity must be selected within a specific range. Therefore, it is necessary to pre-determine the safe range of the phase-shift control quantity based on preset constraints, thereby configuring the upper and lower limits of the phase-shift control quantity. During current sharing control, only the phase-shift control quantity within the range formed by the upper and lower limits will be selected for phase-shift control. This ensures the normal operation of the interleaved parallel resonant converter while achieving current sharing control. This application does not impose any special limitations on the specific type and implementation method of the preset constraints. The specific preset constraints and the number of preset constraints can be flexibly selected according to actual application requirements. Similarly, this application does not impose any special limitations on the specific implementation methods of the upper and lower limits.

[0038] It should be noted that, considering resonant converters typically operate at high frequencies, the switching losses from hard switching are very high, significantly impacting the converter's efficiency (energy conversion efficiency). Therefore, the switching transistors in the primary circuits of each branch of the resonant converter must be able to achieve ZVS (Zero Voltage Switching) to minimize switching losses through this soft-switching process. Furthermore, since the efficiency of an interleaved parallel resonant converter is close to the weighted average of the efficiencies of each branch, low efficiency in any branch will lower the overall efficiency of the interleaved parallel resonant converter. Therefore, the conversion efficiency of each branch must also be sufficiently high to avoid excessive efficiency reduction due to phase-shift control. Simultaneously, to avoid damage to the switching transistors due to excessive voltage stress across them, the voltage stress across all switching transistors must not be too high. For MOSFETs, the voltage stress across the switching transistor specifically refers to the voltage between the drain and source terminals. This application does not impose specific limitations on the specific values ​​of the first and second preset values; they can be set according to actual application requirements. There are multiple ways to set the upper and lower limits, which can be achieved through hardware circuits or software configuration. For example, when using a current sharing loop based on a PI controller to implement the entire current sharing control, an integral term can be added to the PI controller to set the upper and lower limits.

[0039] Specifically, by setting upper and lower limits, the amplitude of the phase-shift control quantity is effectively limited, thereby avoiding the impact of the phase-shift control process on the normal operation of the interleaved parallel resonant converter. The phase-shift control is performed as much as possible to achieve current sharing while avoiding the normal operation of the interleaved parallel resonant converter, ensuring that the interleaved parallel resonant converter can effectively meet the application requirements.

[0040] As an optional embodiment, before determining the average value of the resonant current of each branch in the interleaved parallel resonant converter, the method further includes: Determine whether the frequencies of each branch in an interleaved parallel resonant converter have reached a steady state. If so, proceed to the step of determining the average value of the resonant current of each branch in the interleaved parallel resonant converter; If not, then jump back to the step of determining whether the frequency of each branch in the interleaved parallel resonant converter has reached a steady state.

[0041] Understandably, to achieve accurate and reliable current sharing control, it is typically necessary to intervene only after the frequencies of each branch in the interleaved parallel resonant converter have reached a steady state. The frequency of a branch in an interleaved parallel resonant converter refers to the frequency of the drive signal corresponding to the switch in that branch, i.e., the switching frequency of the switch in that branch. Therefore, before performing current sharing control, it is necessary to determine whether the frequencies of each branch in the interleaved parallel resonant converter have reached a steady state. If the frequencies of each branch have reached a steady state, it indicates that the interleaved parallel resonant converter has reached a stable frequency based on the control process corresponding to normal operation, and the frequencies of each branch will be consistent. At this point, current sharing control can be initiated to collect resonant current and determine the average value. If the frequencies of each branch have not reached a steady state, the frequency determination is repeated until the interleaved parallel resonant converter reaches a steady frequency state before interleaving current sharing control.

[0042] It should be noted that reaching steady state means that the frequency no longer undergoes continuous and regular changes over time, entering a stable, constant, or periodically changing state according to a fixed pattern. This is usually manifested as a fixed frequency or a frequency that fluctuates slightly within a small range. This application does not impose any special limitations on the method for determining whether the frequency has reached steady state; it can be determined by real-time frequency values, such as when the frequency value remains unchanged or the frequency value changes less than a specific value within a preset time period. This application also does not impose any special limitations on the specific method for determining the frequency of each branch in an interleaved parallel resonant converter; it can be determined by acquiring the drive signal in real time.

[0043] Furthermore, there are multiple options for the control process corresponding to the normal operation of the interleaved parallel resonant converter. This application does not impose any particular limitations here, and it can be flexibly adjusted and set according to actual application requirements. The control process corresponding to the normal operation of the interleaved parallel resonant converter can be closed-loop control, such as a closed-loop control process based on the output voltage. The control system samples the output voltage Uout and compares it with the voltage reference value configured internally by the software according to application requirements to generate a voltage error. Then, the voltage error is sent to the voltage loop inside the control system so that the voltage loop can generate a corresponding PFM frequency modulation signal based on the received voltage error. Figure 2Taking the interleaved parallel resonant converter as an example, the control system uses a PWM (Pulse Width Modulation) generation module to generate 12 PWM drive signals of the same frequency corresponding to the 12 switching transistors. These 12 PWM drive signals act one-to-one on each of the 12 switching transistors. Furthermore, the drive signals for the 6 switching transistors in the second branch lag behind the drive signals for the switching transistors in the first branch by 90 degrees (1 / 4 cycle), thus forming a stable interleaved drive control. The control process for normal operation of the interleaved parallel resonant converter can also be open-loop control. For example, the control system first uses a specific soft-start method (such as PWM or PFM) to start the interleaved parallel resonant converter. During the soft start, the frequency will be relatively high. After the soft start is complete, the control system then reduces the frequency of the entire interleaved parallel resonant converter's drive signals to the fixed frequency reference value configured according to application requirements.

[0044] Specifically, current sharing control is introduced after the frequency of each branch in the interleaved parallel resonant converter reaches a steady state. This avoids the influence of pulses caused by inconsistent frequencies of each branch on the sampling results of the resonant current. At the same time, a stable switching frequency can improve the sampling accuracy and reliability, avoid sampling timing errors caused by switching frequency jitter, or the inability to obtain an average value that truly reflects the average situation due to current instability, and ensure the control performance of the current sharing loop.

[0045] As an optional embodiment, the phase-shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and its average value, including: If the resonant current of a branch is less than the average value, then calculate the difference between the average value and the resonant current of the branch. Determine the phase-shift control quantity corresponding to the difference; The drive signal of the secondary circuit in the branch is adjusted based on the phase shift control quantity, including: The driving signal of the secondary circuit in the control branch lags behind the driving signal of the primary circuit in the branch by a phase-shift control amount.

[0046] It is easy to understand that when the resonant current of a certain branch is less than the average value, it indicates that the output current gain of that branch needs to be increased. This can be achieved by applying hysteresis control to the drive signal. The smaller the resonant current of the branch, the larger the difference between it and the average value, and the greater the required increase. Therefore, the corresponding phase-shift control quantity can be determined by calculating the difference between the average value and the resonant current of the branch. Specifically, the phase-shift control quantity is positively correlated with this difference; that is, the larger the difference, the larger the phase-shift control quantity. The specific correspondence between the difference and the phase-shift control quantity can be set and adjusted according to the actual application, and this application does not impose any special limitations here.

[0047] It should be noted that if gain adjustment is achieved by leading the drive signal of the secondary circuit, it may disrupt the soft-switching energy balance between the secondary and primary circuits and potentially alter the natural direction of power transmission, leading to power backflow. Therefore, this embodiment specifically employs lag control to achieve gain adjustment for a particular branch. When a branch requires lag control to increase gain, its secondary circuit drive signal will lag behind the original drive signal generated during normal operation by a phase shift control amount. Since the secondary circuit drive signal needs to be synchronized with the primary circuit drive signal during normal operation to ensure synchronized magnetic and current coupling, the primary circuit drive signal of that branch can be used as a reference for phase shift control. The lag of the secondary circuit drive signal behind the original drive signal generated during normal operation is equivalent to the lag of the secondary circuit drive signal relative to the primary circuit drive signal in the branch. At this point, the hysteresis of the drive signal in the secondary circuit refers to the fact that the drive signals of all switches in the secondary circuit will uniformly lag behind the phase-shift control quantity. This application does not specifically limit the specific implementation method of hysteresis control; a certain rising or falling edge of the drive signal can be selected as the reference for signal hysteresis control. Specifically, hysteresis control can be implemented using a current-sharing loop based on a PI controller, using the difference between the resonant current of this branch and its average value as the error to output the corresponding phase-shift control quantity.

[0048] Specifically, lag control is used to improve branch gain while ensuring the safe operation of the interleaved parallel resonant converter, effectively avoiding power backflow and other issues. At the same time, considering that this phase-shifting control is to improve branch gain, it is necessary to select the branch with resonant current less than the average value as the control object to effectively achieve current sharing control of each branch.

[0049] As an optional embodiment, the phase-shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and its average value, including: If the resonant current of a branch is greater than the average value, then the phase shift control quantity is set to 0; The drive signal of the secondary circuit in the branch is adjusted based on the phase shift control quantity, including: The drive signal of the secondary circuit in the control branch is synchronized with the drive signal of the primary circuit in the branch.

[0050] Understandably, for branches with resonant currents greater than the average value, the phase-shift control can be set to 0, keeping the drive signal of the secondary circuit of that branch unchanged. This maintains the original drive signal generated during normal operation, keeping the drive signals of the secondary circuit and primary circuit synchronized. By applying phase-shift control only to branches with smaller resonant currents to increase gain, current sharing control can be effectively achieved.

[0051] As an optional embodiment, the interleaved parallel resonant converter includes two branches; The phase-shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and its average value, including: Determine the current difference between the average value and the first resonant current; the first resonant current is the resonant current of the primary circuit in the first branch. The phase-shift control quantity is determined based on the current difference; The drive signal of the secondary circuit in the branch is adjusted based on the phase shift control quantity, including: If the current difference is greater than zero, it is determined that the first resonant current is less than the average value, and the driving signal of the secondary circuit in the first branch is controlled to lag the phase shift control amount relative to the driving signal of the primary circuit in the first branch, and the driving signal of the secondary circuit in the second branch is controlled to keep synchronized with the driving signal of the primary circuit in the second branch. If the current difference is less than zero, it is determined that the first resonant current is greater than the average value, and the driving signal of the secondary circuit in the second branch is controlled to lag the phase shift control amount relative to the driving signal of the primary circuit in the second branch, and the driving signal of the secondary circuit in the second branch is controlled to remain synchronized with the driving signal of the primary circuit in the second branch. If the current difference is zero, it is determined that the resonant currents of the two branches are balanced, and the process jumps back to the step of determining the average value of the resonant currents of each branch in the interleaved parallel resonant converter.

[0052] As one specific embodiment, see Figure 4 As shown, Figure 4 This invention provides a schematic diagram of the current sharing control process during the operation of an interleaved parallel resonant converter; Figure 2Taking the interleaved parallel resonant converter with two parallel branches as an example, since there are only two branches in this interleaved parallel resonant converter, after determining the average value of the resonant current, there must be one branch where the resonant current is less than the average value. Either the first branch or the second branch will be subject to lag control. Furthermore, the difference calculated using the resonant current of either the first or the second branch will be consistent. Therefore, this embodiment uses a phase shift angle 'x' with a positive or negative sign to characterize either the first or second branch being subject to lag control, and the corresponding phase shift control quantity is determined by the absolute value. For example... Figure 4 As shown, first, the average value of the resonant currents of the two branches is read, and then the average value is input into the current sharing loop to calculate the phase shift angle x. At this time, the current sharing loop will use the resonant current of the first branch as a reference to calculate the difference, calculate the difference between the average value and the resonant current of the first branch, and determine the phase shift angle x corresponding to the difference. The range of the phase shift angle x is [ A preferred embodiment is... =5°, =-5°.

[0053] When x is greater than zero, it indicates that the resonant current of the first branch is less than the average value. Therefore, the driving signal of the secondary circuit of the first branch needs to be phase-shifted by an angle x relative to the driving signal of its primary circuit. Figure 3 The drive signals S5, S6, S7, and S8 shown are all lagging behind the phase shift angle x of the drive signals S1 and S2. The drive signal of the second branch maintains synchronization between the primary and secondary circuits.

[0054] When x is less than zero, it indicates that the resonant current of the first branch is greater than the average value, meaning the resonant current of the second branch is less than the average value. Therefore, the drive signal of the secondary circuit of the second branch needs to be phase-shifted relative to the drive signal of its primary circuit. Angle, that is Figure 3 The drive signals S9, S10, S11, and S12 shown above lag the drive signals S3 and S4 by the phase shift angle. The drive signal of the first branch maintains the synchronization between the primary and secondary circuits.

[0055] Specifically, by performing phase-shift control only on the branch with smaller resonant current and keeping the drive signal unchanged for the branch with larger resonant current, the control method is simplified, the control cost is reduced, and the control response speed is improved. After the gain of some branches is adjusted, the average value of the resonant current will also change accordingly, which can also effectively achieve current sharing control.

[0056] As an optional embodiment, determining the phase shift control quantity corresponding to the difference includes: Determine the phase shift angle corresponding to the difference; the magnitude of the phase shift angle is positively correlated with the difference. Calculate the ratio between the phase shift angle and the reference value to obtain the per-unit value of the phase shift angle relative to the reference value; the reference value is the angle value corresponding to one complete cycle of the drive signal. The product of the per-unit value and the signal period is determined as the phase-shift control quantity.

[0057] It is easy to understand that, considering the convenience of using a time-based quantity for lag control when performing lag control of the drive signal, allowing the drive signal to lag by a corresponding amount of time, the phase-shift control quantity in this application is specifically a time quantity, i.e., a time length. The current-sharing loop, based on the difference, typically generates a phase-shift angle representing the phase length. Since the phase-shift angle is an angular quantity, it needs to be converted into a corresponding phase-shift control quantity. Specifically, the phase-shift angle is first standardized to per-unit value, and then converted into a phase-shift control quantity based on the signal period. This application does not specifically limit the specific implementation method of the reference value; it is generally 2π.

[0058] Specifically, after the current sharing loop outputs the corresponding phase shift angle, the phase shift angle is normalized relative to 2π per unit. The product of this normalized value and the signal period stored internally in the driving module (e.g., the PWM generation module) that generates the driving signal is then used as the final control quantity for phase shift control. This application does not impose specific limitations on the specific implementation methods of the signal period and phase shift control quantity; they can be implemented by storing them in registers. For example, the signal period is usually stored in a PWM period register, and the phase shift control quantity can be implemented by storing it in a preset phase shift register. During current sharing control, the value of the phase shift register is directly read to adjust the phase shift angle of the corresponding signal carrier (e.g., a triangular carrier) of the corresponding output channel of the driving module (the output channel of the driving signal of the secondary circuit of the corresponding branch). The current sharing control process is executed periodically, and automatic adjustment of current balance in each branch is achieved by periodically updating the value of the phase shift register.

[0059] Specifically, the implementation method of the phase-shift control quantity can be flexibly changed according to the actual application, which facilitates the control system or current sharing loop to achieve current sharing control.

[0060] See Figure 5 As shown, Figure 5 This is a schematic diagram of the structure of an electronic device provided by the present invention. To solve the above-mentioned technical problems, the present invention also provides an electronic device, comprising: Memory 21 is used to store computer program 212; Processor 22 is used to implement the steps of the control method for the interleaved parallel resonant converter as described above.

[0061] The processor 22 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 22 may be implemented using at least one hardware form selected from DSP (Digital Signal Processor), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor, also known as the central processing unit, is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 22 may integrate a GPU (graphics processing unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 22 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0062] The memory 21 may include one or more computer-readable storage media, which may be non-transitory. The memory 21 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 21 is used to store at least the following computer program 212, which, after being loaded and executed by the processor 22, is capable of implementing the relevant steps of the control method for the interleaved parallel resonant converter disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 21 may also include an operating system 211 and data, and the storage method may be temporary or permanent storage. The operating system 211 may include Windows, Unix, Linux, etc. The data may include, but is not limited to, the data in the control method for the interleaved parallel resonant converter.

[0063] In some embodiments, the electronic device may further include a display screen, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. Those skilled in the art will understand that... Figure 5 The illustration does not constitute a limitation on the electronic device and may include more or fewer components than shown.

[0064] For an introduction to the electronic device provided by this invention, please refer to the embodiment of the control method for the interleaved parallel resonant converter described above; the present invention will not be repeated here.

[0065] To address the aforementioned technical problems, the present invention also provides an interleaved parallel resonant converter, comprising the aforementioned electronic equipment and M branches, wherein the M branches are connected in parallel; M is a positive integer greater than 1.

[0066] It is easy to understand that the electronic device provided in the above embodiments can effectively achieve current sharing control of each branch in the interleaved parallel resonant converter by executing the control method of the interleaved parallel resonant converter. The output terminal of the electronic device can be directly connected to the control terminal of the switching transistor in the branch, and output the adjusted drive signal for current sharing control to control the operation of the switching transistor in the branch; or the output terminal of the electronic device can be connected to the control system of the interleaved parallel resonant converter, and after adjusting the drive signal output by the control system of the interleaved parallel resonant converter to each switching transistor based on the application requirements of normal operation, the adjusted drive signal is then output to the control terminal of the switching transistor to control the operation of the switching transistor in the branch. There are multiple options for the coordination between the current sharing control logic implemented by the electronic device and the control logic of the control system of the interleaved parallel resonant converter during normal operation, and this application does not make any particular limitation here.

[0067] For an introduction to the interleaved parallel resonant converter provided by this invention, please refer to the embodiments of the control method for the interleaved parallel resonant converter described above. This invention will not be repeated here.

[0068] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the control method for the interleaved parallel resonant converter as described above.

[0069] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this application. Specifically, the computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, and portable hard drives, or any type of media or device suitable for storing instructions or data, etc., and this application does not make any special limitations here.

[0070] For an introduction to the computer-readable storage medium provided by the present invention, please refer to the embodiments of the control method for the interleaved parallel resonant converter described above; the present invention will not be repeated here.

[0071] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatuses disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. It should also be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0072] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for an interleaved parallel resonant converter, characterized in that, include: Determine the average value of the resonant current in each branch of the interleaved parallel resonant converter; For any branch, the phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value. The driving signal of the secondary circuit in the branch is adjusted based on the phase shift control amount to achieve current balance in each branch.

2. The control method for the interleaved parallel resonant converter according to claim 1, characterized in that, Also includes: The safe range of the phase shift control quantity is determined according to preset constraints; The preset constraints include one or more combinations of the following: the switching transistors in the primary circuit of each branch can achieve zero-voltage conduction; the conversion efficiency of each branch is greater than or equal to a first preset value; and the voltage stress across the switching transistors in each branch is less than or equal to a second preset value. The upper and lower limits of the phase shift control quantity are defined based on the safe interval; the upper limit is less than or equal to the upper limit of the safe interval, and the lower limit is greater than or equal to the lower limit of the safe interval.

3. The control method for the interleaved parallel resonant converter according to claim 1, characterized in that, Before determining the average value of the resonant current in each branch of the interleaved parallel resonant converter, the following steps are also included: Determine whether the frequencies of each branch in an interleaved parallel resonant converter have reached a steady state. If so, proceed to the step of determining the average value of the resonant current of each branch in the interleaved parallel resonant converter; If not, then jump back to the step of determining whether the frequency of each branch in the interleaved parallel resonant converter has reached a steady state.

4. The control method for the interleaved parallel resonant converter according to any one of claims 1 to 3, characterized in that, The phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value, including: If the resonant current of the branch is less than the average value, then calculate the difference between the average value and the resonant current of the branch. Determine the phase shift control quantity corresponding to the difference; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: The driving signal of the secondary circuit in the control branch lags behind the driving signal of the primary circuit in the control branch by the phase shift control amount.

5. The control method for the interleaved parallel resonant converter according to claim 4, characterized in that, The phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value, including: If the resonant current of the branch is greater than the average value, then the phase shift control quantity is set to 0; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: The drive signal of the secondary circuit in the control branch is kept synchronized with the drive signal of the primary circuit in the control branch.

6. The control method for the interleaved parallel resonant converter according to claim 5, characterized in that, The interleaved parallel resonant converter includes two branches; The phase shift control quantity corresponding to the branch is determined based on the relationship between the resonant current of the branch and the average value, including: Determine the current difference between the average value and the first resonant current; the first resonant current is the resonant current of the primary circuit in the first branch; The phase shift control quantity is determined based on the current difference; Adjusting the drive signal of the secondary circuit in the branch based on the phase shift control amount includes: If the current difference is greater than zero, it is determined that the first resonant current is less than the average value, and the driving signal of the secondary circuit in the first branch is controlled to lag behind the phase shift control amount relative to the driving signal of the primary circuit in the first branch, and the driving signal of the secondary circuit in the second branch is controlled to remain synchronized with the driving signal of the primary circuit in the second branch. If the current difference is less than zero, it is determined that the first resonant current is greater than the average value, and the driving signal of the secondary circuit in the second branch is controlled to lag behind the driving signal of the primary circuit in the second branch by the phase shift control amount, and the driving signal of the secondary circuit in the second branch is controlled to remain synchronized with the driving signal of the primary circuit in the second branch. If the current difference is zero, it is determined that the resonant currents of the two branches are balanced, and the process jumps back to the step of determining the average value of the resonant currents of each branch in the interleaved parallel resonant converter.

7. The control method for the interleaved parallel resonant converter according to claim 4, characterized in that, Determining the phase shift control quantity corresponding to the difference includes: Determine the phase shift angle corresponding to the difference; the magnitude of the phase shift angle is positively correlated with the difference. Calculate the ratio between the phase shift angle and the reference value to obtain the per-unit value of the phase shift angle relative to the reference value; the reference value is the angle value corresponding to one complete cycle of the drive signal; The product of the per-unit value and the signal period is determined as the phase-shift control quantity.

8. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for implementing the steps of the control method for an interleaved parallel resonant converter as described in any one of claims 1 to 7.

9. An interleaved parallel resonant converter, characterized in that, It includes the electronic device as described in claim 8 and M branches, wherein the M branches are connected in parallel, and the electronic device is connected to the driving terminal of each branch; M is a positive integer greater than 1.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the control method for the interleaved parallel resonant converter as described in any one of claims 1 to 7.

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