Current sharing control method, system and device for multi-module parallel power supply and readable storage medium

Abstract

The invention discloses a current sharing control method, system and device for a multi-module parallel power supply and a readable storage medium, and the method comprises the steps: obtaining a feedback signal representing the primary side current of a transformer of each power module, and enabling the power modules to be connected in parallel; comparing each feedback signal with a common current reference signal to generate a current error signal of each power module; and based on the current error signal, adjusting the duty ratio of a main power switch tube of the corresponding power module, and carrying out current sharing control on the power module. According to the invention, localization and direct closed-loop control of the current of each power module are realized, dependence on a current sharing communication bus between the power modules is not needed, the system architecture is simplified, and the cost and complexity are reduced.

Description

Current sharing control method, system, device and readable storage medium for multi-module parallel power supplies Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a current sharing control method, system, device, and readable storage medium for a multi-module parallel power supply. Background Technology

[0002] In the field of high-efficiency, high-power, low-voltage direct current (LVDC) power supplies, using multiple power conversion modules in parallel is a common technique to improve system output power and reliability. By connecting them in parallel, the total output current can be distributed, reducing the current stress on individual modules and thus enabling the construction of power supply systems with higher power ratings.

[0003] However, in systems with multiple power modules connected in parallel, due to inherent deviations in the parameters of components (such as transformers, inductors, and switching transistors) within each module, even when the same control signal is applied to each module, the actual output current is difficult to maintain consistency. This uneven current distribution can lead to some modules operating under overload for extended periods, causing problems such as localized overheating, increased device stress, and reduced lifespan, thus becoming a bottleneck restricting the overall system's output power and reliability.

[0004] Therefore, there is an urgent need in this field for an effective current sharing control method that can quickly and accurately adjust the output of each parallel module automatically to ensure that the current is evenly distributed. Summary of the Invention

[0005] This application provides a current sharing control method, system, device, and readable storage medium for a multi-module parallel power supply, which realizes automatic, rapid, and accurate current balancing among multiple power modules, thereby at least partially solving the above-mentioned technical problems.

[0006] To achieve the above objectives, in a first aspect, a current sharing control method for a multi-module parallel power supply is provided, comprising the following steps: acquiring feedback signals characterizing the primary current of each power module connected in parallel with the transformer primary current, wherein each power module is connected in parallel; comparing each feedback signal with a common current reference signal to generate a current error signal for each power module; and adjusting the duty cycle of the main power switch transistor of the corresponding power module based on the current error signal to perform current sharing control on the power modules.

[0007] Optionally, the step of adjusting the duty cycle of the main power switch of the corresponding power module based on the current error signal to perform current sharing control on the power module includes: increasing the duty cycle of the main power switch of the corresponding power module when the current error signal is greater than a first threshold; decreasing the duty cycle of the main power switch of the corresponding power module when the current error signal is less than the first threshold; and keeping the duty cycle of the main power switch of the corresponding power module unchanged when the current error signal is equal to the first threshold.

[0008] Optionally, the method further includes: sampling the total output voltage of the multi-module parallel power supply system; comparing the total output voltage with a preset voltage reference value; generating a current amplitude command through a voltage loop controller; and using the current amplitude command as the shared current reference signal.

[0009] Optionally, obtaining the feedback signal characterizing the primary current of each power module connected in parallel includes: obtaining a mutual inductance secondary current proportional to the primary current of the transformer through a current transformer connected in series in the primary circuit of the power module; and converting the mutual inductance secondary current into a feedback signal characterizing the primary current of the transformer.

[0010] Optionally, during the conduction of the clamping switch of the corresponding power module, the process of converting the mutual inductor secondary current into a feedback signal characterizing the transformer primary current is performed.

[0011] Optionally, at the duty cycle time corresponding to the preset ratio of the PWM cycle of the power module, the feedback signal that converts the mutual inductor secondary current into a characterizing the transformer primary current is executed.

[0012] Secondly, a current sharing control system for a multi-module parallel power supply is also proposed, comprising multiple parallel power modules, and further comprising: a current detection and sampling circuit; and a control unit connected to the current detection and sampling circuit and each power module, configured to: control the current detection and sampling circuit to acquire feedback signals characterizing the primary current of the transformer of each power module; compare each feedback signal with a common current reference signal to generate a current error signal for each power module; and adjust the duty cycle of the main power switch of the corresponding power module based on the current error signal to perform current sharing control on the power modules.

[0013] Thirdly, a control device is also proposed, including a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements the method described in the embodiments of this application.

[0014] Fourthly, a computer-readable storage medium is also proposed, on which a computer program is stored, which, when executed by a processor, implements the method described in the embodiments of this application.

[0015] The above technical solution achieves localized, direct closed-loop control of the current in each power module by directly acquiring the current signal from the primary side of the transformer in each power module and independently adjusting the duty cycle of the corresponding power module. This eliminates the need for a current-sharing communication bus between power modules, simplifying the system architecture and reducing cost and complexity. Furthermore, by performing independent and rapid closed-loop adjustment on the primary side of each power module, current deviations caused by component parameter dispersion can be promptly suppressed, effectively improving the system's current-sharing accuracy and dynamic response capability from the source, and ensuring the stable operation of the parallel system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 is a structural schematic diagram of the current sharing control system of a multi-module parallel power supply according to an exemplary embodiment of the present disclosure; Figure 2 is a circuit diagram of the current sharing control system of a multi-module parallel power supply according to an exemplary embodiment of the present disclosure; Figure 3 is a circuit diagram of the current detection and sampling circuit according to an exemplary embodiment of the present disclosure; Figure 4 is a flowchart of the current sharing control method of a multi-module parallel power supply according to an exemplary embodiment of the present disclosure; Figure 5 is a timing diagram of the current sharing control method of a multi-module parallel power supply according to an exemplary embodiment of the present disclosure; Figure 6 is a functional module schematic diagram of the current sharing control device of a multi-module parallel power supply according to an exemplary embodiment of the present disclosure.

[0018] The realization of the objectives, functional features and advantages of the embodiments of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] Furthermore, descriptions involving "first," "second," etc., in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0021] Based on the current sharing problem in multi-module parallel power supply systems mentioned in the background, existing technologies typically employ multiple forward active clamp power modules connected in parallel to increase output power. However, due to inherent deviations in the component parameters of each power module, uneven current distribution occurs during parallel operation, leading to overload of some modules and restricting the overall system performance and reliability.

[0022] Existing solutions to this problem typically rely on sampling and comparing the output current of each module, or on complex communication and coordination mechanisms to achieve current sharing control. These solutions fail to fully utilize the primary-side current information during power conversion, and also fail to achieve fast, independent closed-loop regulation within each module, resulting in limited system response speed and current sharing accuracy.

[0023] To address the aforementioned technical problems, this application proposes a current sharing control method, system, device, and readable storage medium for multi-module parallel power supplies. The method acquires sampling signals characterizing the primary current of each power module transformer and independently adjusts the duty cycle of the corresponding power module's main power switch based on these signals, achieving rapid and direct closed-loop control of the current in each power module. This solution eliminates the need for complex inter-module communication and coordination, effectively solving the dynamic current sharing problem in multi-module parallel systems through distributed primary current closed-loop control, significantly improving the system's current sharing accuracy, dynamic response speed, and overall reliability.

[0024] This application proposes a current sharing control system for a multi-module parallel power supply.

[0025] Please refer to Figure 1, which is a schematic diagram of the current sharing control system of a multi-module parallel power supply according to an embodiment of this application.

[0026] The current sharing control system 10 of the multi-module parallel power supply includes multiple parallel power modules 11, and also includes a current detection sampling circuit 12, which is configured to acquire feedback signals characterizing the transformer primary current of each power module 11.

[0027] The control unit 13, connected to the current detection and sampling circuit 12 and each of the power modules 11, is configured to: control the current detection and sampling circuit 12 to acquire feedback signals characterizing the transformer primary current of each power module 11; compare each feedback signal with a common current reference signal to generate a current error signal for each power module; and adjust the duty cycle of the main power switch of the corresponding power module 11 based on the current error signal to perform current sharing control on the power module 11.

[0028] Among them, the main power switching transistor is a switching device in the power module that is connected in series with the primary winding of the transformer and is responsible for controlling the transmission of energy from the input end to the transformer.

[0029] It should be noted that the power module is a DC-DC converter module that includes a transformer to achieve electrical isolation and energy transmission.

[0030] In the embodiments of this application, by directly acquiring the current signal of the primary side of each power module transformer and independently adjusting the duty cycle of the corresponding power module accordingly, localized and direct closed-loop control of the current of each power module is achieved. This eliminates the need to rely on the current sharing communication bus between power modules, simplifying the system architecture and reducing cost and complexity. Simultaneously, by performing independent and rapid closed-loop adjustment on the primary side of each power module, current deviations caused by component parameter dispersion can be promptly suppressed, effectively improving the current sharing accuracy and dynamic response capability of the system from the source, and ensuring the stable operation of the parallel system.

[0031] In some embodiments, the current detection sampling circuit 12 includes a plurality of current transformers 120, the primary winding of each current transformer 120 is connected in series in the primary circuit of the transformer of the corresponding power module 11, and each current transformer also includes a secondary winding, the secondary winding outputting a mutual inductance secondary current proportional to the primary current of the transformer.

[0032] Please refer to Figure 2, which is a circuit diagram of the current sharing control system of the multi-module parallel power supply according to an embodiment of this application. In a specific embodiment, as shown in Figure 2, the multi-module parallel power supply is a three-phase interleaved forward active clamp power supply module. The structure and working principle of the current sharing control system of the multi-module parallel power supply according to an embodiment of this application will be described below with reference to Figure 2.

[0033] As shown in Figure 2, the current sharing control system 10 of the multi-module parallel power supply includes three independent DC-DC converters connected in parallel and operating in staggered phases to reduce input and output current ripple and improve overall efficiency. Each DC-DC converter constitutes a power module, such as the first power module 11a, the second power module 11b, and the third power module 11c. All power modules are topologically identical, being forward active clamp power modules. The following description uses the second power module 11b (corresponding to the upper module in Figure 2, with the third main power switch Q3, the fourth main power switch Q4, and the second transformer T2 as examples) as an example. The other two power modules (with the main power switch Q1, clamping switch Q2, and transformer T1 as examples, and the main power switch Q5, clamping switch Q6, and transformer T3 as examples) have the same structure and will not be elaborated upon.

[0034] Specifically, the second power module 11b mainly includes the following components, and their connection relationship is shown in Figure 2: one end of the clamping capacitor C3 is connected to the drain of the main power switch Q4, and the other end of the clamping capacitor C3 is connected to the drain of the main power switch Q3. The drain of the main power switch Q3 is also connected to the non-same-name terminal of the primary winding of transformer T2. The same-name terminal of the primary winding of transformer T2 is connected in series with one end of the primary winding of current transformer CT2 (i.e., the primary winding of the current transformer) CT2-A, and the other end of the primary winding of current transformer CT2 CT2-A is connected to the DC positive input terminal DC+.

[0035] Transformer T2 serves as an isolation and energy transfer unit. Its secondary winding's corresponding terminal is connected to the anode of rectifier diode D3. The cathode of rectifier diode D3, along with the cathode of freewheeling diode D4 and one end of energy storage inductor L2, are connected to the first node. The other end of energy storage inductor L2 and the positive terminal of filter capacitor C4 are connected to the second node, which serves as the output terminal of the second power module 11b. The negative terminal of filter capacitor C4, the non-corresponding terminal of the secondary winding of transformer T2, and the anode of freewheeling diode D4 are all grounded. Energy storage inductor L2 smooths the current, and filter capacitor C4 filters the voltage to ensure load voltage stability.

[0036] The gate of the main power switch Q3 is connected to the drive signal DRV3 to control the energy transfer of the transformer T2. Exemplarily, the main power switch Q3 is a MOSFET. When the main power switch Q3 is turned on, the input voltage is applied to the primary side of the transformer T2. The gate of the clamping switch Q4 is connected to the drive signal DRV4, and it conducts complementaryly to the main power switch Q3. The clamping capacitor C3 is used to absorb the magnetizing energy of the transformer T2, achieving soft switching and reducing switching losses. The drive signals DRV3 and DRV4 are complementary conduction signals and have a dead time to prevent shoot-through.

[0037] In forward converter operation, rectifier diode D3 conducts when transformer T2 is transmitting energy, and freewheeling diode D4 conducts when transformer T2 is reset, providing continuous current to the load. Optionally, when synchronous rectification is used, rectifier diode D3 and freewheeling diode D4 can be replaced with MOSFETs, and a synchronous rectification control circuit (not shown in the figure) needs to be added to further improve efficiency.

[0038] The secondary winding (i.e., the secondary winding of the current transformer) CT2-B (as shown in Figure 3) outputs a feedback signal characterizing the average primary current of the transformer of the second power module 11b. This signal is sent to the control unit 13 (not shown in the figure) as a current feedback signal.

[0039] The input terminals (DC+, DC-) of the three power modules 11a, 11b, and 11c are connected in parallel to receive the same DC input. The output terminals (i.e., the positive terminals of capacitors C4, C2, and C6) of the three power modules 11a, 11b, and 11c are also directly connected in parallel to supply power to the load.

[0040] Each power module is equipped with a corresponding current detection and sampling circuit (e.g., 12a, 12b, 12c). Specifically, a current transformer (e.g., CT1, CT2, CT3) is connected in series in the primary circuit of the transformer of each power module to detect the primary current of the corresponding power module and output a feedback signal to the control unit 13. This feedback signal serves as the feedback quantity for current sharing control. For example, the feedback signal of current transformer CT2 reflects the instantaneous power level of the second power module 11b.

[0041] The gates of the main power switches (such as Q1, Q3, Q5) and clamping switches (such as Q2, Q4, Q6) of each power module are controlled by independent drive signals (such as DRV1 / DRV2, DRV3 / DRV4, DRV5 / DRV6). This independent drive connection is a prerequisite for achieving interleaved control and independent adjustment of the duty cycle of each power module to achieve current sharing.

[0042] Each power module's operating cycle consists of two phases: the main switch conduction phase and the secondary phase. When the main power switch Q3 turns on in response to the drive signal DRV3, the input DC voltage is applied to the primary side of transformer T2, and energy is coupled to the secondary side. At this time, rectifier diode D3 is forward-biased, while freewheeling diode D4 is reverse-biased. The secondary current of transformer T2 supplies power to the load through rectifier diode D3, while energy storage inductor L2 stores energy and filter capacitor C4 charges.

[0043] Main switch turn-off phase: After the main power switch Q3 is turned off, the clamping switch Q4 is turned on under the control of the drive signal DRV4. The excitation energy of transformer T2 is fed back to the input terminal through the loop formed by clamping capacitor C3 and clamping switch Q4, realizing the reset of transformer T2 and energy recovery. At this time, the rectifier diode D3 on the secondary side of transformer T2 is reverse cut off, the freewheeling diode D4 is forward turned on, the energy storage inductor L2 releases energy, and continues to supply power to the load through the freewheeling diode D4, maintaining the voltage on the filter capacitor C4.

[0044] This alternating operation enables high-efficiency energy conversion of the power module.

[0045] In some embodiments, the control unit 13 is further configured to generate a drive signal that is complementary to the drive signal of the main power switch and has a dead time inserted, so as to control the clamping switch in the same group, such that the duty cycle of the clamping switch passively follows the change of the duty cycle of the main power switch.

[0046] Specifically, regarding the generation of drive signals for the switching transistors in each power module, the control unit 13 is configured to perform the following operations: For each power module 11, firstly, a drive signal DRV3 for the main power switching transistor (e.g., Q3) is generated; subsequently, based on this drive signal DRV3, a complementary drive signal DRV4 with a dead time is generated synchronously through logic inversion and dead-time insertion, used to control the clamping switching transistor Q4 in the same group. The duty cycle of the clamping switching transistor Q4 thus passively follows the duty cycle of the main power switching transistor Q3. When the duty cycle of the main power switching transistor Q3 is adjusted due to the need for current sharing control, the duty cycle of the clamping switching transistor Q4 will automatically change accordingly in a complementary manner.

[0047] Furthermore, current sharing control for multiple power modules is achieved by detecting the primary current of the transformer. Specifically, a current transformer (such as CT1, CT2, CT3) is connected in series with the primary side of the transformer of each power module. For example, current transformer CT2 is used for the second power module 11b, and its output feedback signal characterizes the average primary current of the second power module 11b. This feedback signal is input to the control unit 13.

[0048] The control unit 13 compares multiple current values ​​based on the feedback signals input from each power module. If the current of a power module deviates from the average value, the drive duty cycle of the main power switch (e.g., Q3) of that power module is adjusted. For example, if the feedback signal from the current transformer CT2 indicates a low current, the control unit 13 increases the duty cycle of the main power switch Q3 by adjusting the duty cycle of DRV3, thereby increasing the output power of that power module 11b and ensuring that the power is evenly distributed among the three power modules. This active current sharing method ensures the current balance of the parallel power modules and avoids overheating or reliability problems caused by parameter differences.

[0049] In this embodiment, the current sharing control of the multi-module parallel power supply is integrated into the overall control loop, and sampling and duty cycle adjustment are implemented using a digital signal processor (DSP) or a dedicated IC, but it is not limited to this.

[0050] As shown in Figure 2, this multi-module parallel power supply system adopts a three-phase interleaved parallel forward active clamp topology, achieving high-efficiency and high-power-density LVDC conversion. The system's current sharing control is based on the detection of the primary current of the power module transformers; the control scheme is simple and efficient, ensuring stable and reliable operation of the system under high-power output conditions. This design has good scalability, and can adapt to higher power level application requirements by increasing the number of parallel power modules.

[0051] The above description, in conjunction with Figure 2, details one specific implementation of the power module. Those skilled in the art should understand that various modifications can be made to the embodiments without departing from the essential scope of the present invention. For example, adjusting circuit component parameters or using synchronous rectification technology to replace the diode rectification scheme should all be considered to fall within the protection scope of this application.

[0052] In some embodiments, the current detection sampling circuit 12 further includes a plurality of sampling units 121, each sampling unit 121 being connected to a secondary winding of a current transformer 120, the sampling unit 121 being configured to convert the secondary current into a voltage signal characterizing the primary current during the conduction of the clamping switch of the power module 11.

[0053] Please also refer to Figure 3, which is a schematic diagram of the current detection sampling circuit of an embodiment of this application.

[0054] The current detection sampling circuit 12 is configured independently for each power module 11. The following detailed description uses the second current detection sampling circuit 12b, which is paired with the current transformer CT2 of the second power module, as an example. This second current detection sampling circuit 12b consists of components such as the current transformer CT2, rectifier diode D7, first voltage divider resistor R1, second voltage divider resistor R2, and third resistor R3. The specific connection relationships of each component are as follows: The primary winding CT2-A of the current transformer CT2 is connected in series in the primary main circuit of the transformer T2 of the second power module 11b. One end of the secondary winding CT2-B of the current transformer CT2 is connected to the anode of the rectifier diode D7. The first voltage divider resistor R1 is connected in series between the cathode of the rectifier diode D7 and the third node, which serves as the output node for the feedback signal, outputting a voltage signal identified as CS. One end of the first voltage divider resistor is connected to the cathode of the rectifier diode D7, and the other end is connected to one end of the second voltage divider resistor R2. The other end of the second voltage divider resistor R2 is connected to the reference ground PGND. The first voltage divider resistor R1 and the second voltage divider resistor R2 form a voltage divider network, which is connected in series between the cathode of the rectifier diode D7 and the reference ground PGND. One end of the third resistor R3 is connected to the anode of the rectifier diode D7 to the secondary winding CT2-B, and the other end is connected to the reference ground PGND.

[0055] The secondary winding CT2-B of the current transformer CT2 induces an AC current signal that is proportional to the current of the primary winding CT2-A (the proportionality coefficient is the turns ratio of CT2-B to CT2-A).

[0056] The working principle of the current detection sampling circuit 12b is based on the current transformation and unidirectional sampling principle of the current transformer. The specific working process is as follows: When the main power switch Q3 of the second power module 11b is turned off and the clamping switch Q4 is turned on, the primary excitation current (or reset current) of the transformer T2 flows through the primary winding CT2-A of the current transformer CT2 in the second current detection sampling circuit 12b. At this time, a corresponding current is induced in the secondary winding CT2-B of the current transformer CT2. Since the direction of the induced current causes the rectifier diode D7 to be forward biased, the induced current flows through the rectifier diode D7 and enters the voltage divider sampling network composed of the first voltage divider resistor R1 and the second voltage divider resistor R2. The current flowing through the voltage divider network generates a voltage drop across the first voltage divider resistor R1 and the second voltage divider resistor R2. Finally, a positive pulse voltage signal CS is generated on the second voltage divider resistor R2. The instantaneous amplitude of the voltage signal CS is proportional to the instantaneous value of the secondary current of the current transformer CT2, thus reflecting the magnitude of the instantaneous current of the primary current of the transformer in power module 11b.

[0057] When the main power switch Q3 of the second power module 11b is turned on and the clamping switch Q4 is turned off, the direction or magnitude of the current flowing through the primary winding CT2-A of the current transformer CT2 changes, causing a reverse electromotive force to be induced in the secondary winding CT2-B of the current transformer CT2. At this time, the rectifier diode D7 is cut off due to reverse bias. The third resistor R3 provides a freewheeling circuit for the secondary winding CT2-B of the current transformer CT2, ensuring that the voltage signal CS quickly falls back to near zero potential, preparing for the next sampling cycle.

[0058] Since the voltage signal CS is a periodic pulse signal, its peak value is proportional to the peak current of the primary side, and the pulse width is consistent with the conduction time of the clamping switch Q4. The control unit 13 samples the voltage value of this voltage signal CS at fixed time points (e.g., at a specific moment during the conduction period of the clamping switch Q4), or obtains information characterizing the average current of the transformer primary side by calculating the average value of multiple cycles, for use in subsequent current sharing control algorithms.

[0059] In some embodiments, the control unit 13 is configured to sample the voltage signal output by the sampling unit 121 corresponding to the power module 11 during the conduction of the clamping switch of the power module 11, and adjust the duty cycle of the main power switch of the corresponding power module 11 according to the sampling result to perform current sharing control on the power module.

[0060] The control unit 13 acquires the current feedback signals corresponding to the three power modules through its multiple internal ADC (analog-to-digital converter) channels. The control unit 13 does not directly use the instantaneous value of the voltage signal CS, but samples this pulse voltage at a fixed moment in each switching cycle, that is, at the peak current moment when the clamping switch Q4 is turned on, or calculates the value that can characterize the average current of the transformer primary side of the power module through digital algorithms (such as obtaining the average value of multiple cycles).

[0061] It should be noted that during the conduction period of the clamping switch, the main power switch is in the off state, and the current in the primary circuit of the transformer is a relatively stable excitation reset current. During this period, the sampling unit 121 can naturally conduct and acquire the signal. In this way, the high-frequency noise interference generated by the operation of the main power switch is avoided, thereby obtaining a current feedback signal (CS) with high signal-to-noise ratio and high stability.

[0062] In some embodiments, the control unit 13 is configured to: sample the total output voltage of the system, compare the total output voltage with a preset voltage reference value, generate a current amplitude command through voltage loop processing, and use the current amplitude command as a common current reference signal; compare the current reference signal with each of the sampled signals (i.e., feedback signals characterizing the primary current of each power module transformer) to generate a current error signal for each power module; and adjust the duty cycle of the main power switch transistor of the corresponding power module based on each of the current error signals.

[0063] Specifically, the control unit 13 samples the total output voltage of the system power supply to generate a unified current reference signal. This current reference signal also serves as the target current value for the three parallel power modules. Each power module 11 compares its sampled signal with this current reference signal and then independently generates a drive signal for the PWM duty cycle of its main power switching transistors (such as Q1, Q3, and Q5). Since the three power modules share a single current reference signal, the system automatically adjusts the output current of each power module to be consistent, thereby achieving precise active current sharing. The specific current sharing control principle will be explained in detail below.

[0064] In the embodiments of this application, by connecting a current transformer in series with the primary winding of the power module transformer and combining it with unidirectional sampling rectified by diodes, the voltage signal characterizing the average current of the primary winding of each power module can be obtained efficiently, accurately, and at low cost. This design provides a reliable hardware foundation for the subsequent implementation of multi-module natural current sharing based on the average current control mode, effectively ensuring the stability and reliability of the system under high-power conditions.

[0065] This application also proposes a current sharing control method for multi-module parallel power supplies.

[0066] Please also refer to Figure 4, which is a flowchart illustrating the current sharing control method for a multi-module parallel power supply according to an embodiment of this application. The current sharing control method for the multi-module parallel power supply is applied to the current sharing control system for a multi-module parallel power supply as described in this embodiment. The current sharing control method for the multi-module parallel power supply includes the following steps: Step S401, obtaining feedback signals characterizing the primary current of the transformer of each power module connected in parallel, wherein each power module is connected in parallel.

[0067] Specifically, as shown in Figures 2 and 3 and their corresponding descriptions, current transformers (such as CT1, CT2, and CT3) connected in series in the primary circuit of each power module transformer detect the primary current of each power module transformer during the conduction period of the clamping switch transistors (such as Q2, Q4, and Q6) of the corresponding power module. The current signal is processed by its respective sampling unit (such as D5, R1, R2, and C1) and converted into a voltage signal proportional to the average value of the primary current, i.e., the current feedback signal.

[0068] Step S402: Compare each of the feedback signals with a common current reference signal to generate a current error signal for each of the power modules.

[0069] Step S403: Based on the current error signal, adjust the duty cycle of the main power switch of the corresponding power module to perform current sharing control on the power module.

[0070] In some embodiments, obtaining the feedback signal characterizing the primary current of each power module connected in parallel includes: obtaining a mutual inductance secondary current proportional to the primary current of the transformer through a current transformer connected in series in the primary circuit of the power module; and converting the mutual inductance secondary current into a feedback signal characterizing the primary current of the transformer.

[0071] In some embodiments, during the conduction of the clamping switch of the corresponding power module, the process of obtaining a mutual inductance secondary current proportional to the primary current of the transformer is performed through a current transformer connected in series in the primary circuit of the power module.

[0072] In some embodiments, at the duty cycle time corresponding to a preset proportion of the PWM cycle of the power module, the process of obtaining the mutual inductance secondary current proportional to the primary current of the transformer through the current transformer connected in series in the primary circuit of the power module is executed.

[0073] In one specific embodiment, the preset ratio is 50%. To improve sampling accuracy and avoid switching noise interference, the control unit 13 triggers sampling at the midpoint of the cycle of each PWM drive signal (i.e., at 50% duty cycle) through the ADC (analog-to-digital converter) module to obtain the current sampling detection value at that moment. Each PWM drive signal corresponds to driving the main power switch of a power module.

[0074] In some embodiments, the method further includes: sampling the total output voltage of the system, comparing the total output voltage with a preset voltage reference value, generating a current amplitude command through voltage loop processing, and using the current amplitude command as the shared current reference signal.

[0075] Specifically, the total output voltage of the sampling system is obtained by the control unit 13 through its internal voltage sampling circuit, which continuously acquires the total output voltage signal Vsense of the power supply system. This signal characterizes the overall operating status of the power supply system.

[0076] In some embodiments, adjusting the duty cycle of the main power switch of the corresponding power module based on the current error signal includes: increasing the duty cycle of the main power switch of the corresponding power module when the current error signal is greater than a first threshold; decreasing the duty cycle of the main power switch of the corresponding power module when the current error signal is less than the first threshold; and keeping the duty cycle of the main power switch of the corresponding power module unchanged when the current error signal is equal to the first threshold.

[0077] Please refer to Figure 5, which is a timing diagram of the current sharing control method for a multi-module parallel power supply according to an embodiment of this application. The following, in conjunction with the control block diagram and timing diagram shown in Figure 5, uses a 2kW LVDC power supply employing a three-phase interleaved forward active clamp topology as an example to describe in detail the specific implementation steps of the current sharing control method for a multi-module parallel power supply according to an embodiment of this application.

[0078] The control unit 13 continuously acquires the total output voltage signal Vsense of the power system through a voltage sampling circuit. The primary current of each power module 11 is detected in real time by current transformers CT1, CT2, and CT3 connected in series in the primary circuit of each power module 11 transformer. After processing by their respective sampling units 121, the current signals are converted into voltage signals proportional to the average value of the primary current, namely, the current detection signals Isense1, Isense2, and Isense3, respectively.

[0079] The total output voltage signal Vsense is compared with the preset voltage reference value Vref to calculate the voltage error signal Verror, where Verror = Vref - Vsense.

[0080] The control unit 13 calculates the voltage error signal Verror through a voltage loop PI (proportional-integral) regulator, outputting a unified current reference signal Unsv. This current reference signal Unsv reflects the total current level required to stabilize the output voltage. Subsequently, the current reference signal Unsv is equally distributed to the current target values ​​of each power module, i.e., Iref1 = Iref2 = Iref3 = Unsv, meaning that the three power modules 11 are assigned the same current target value.

[0081] The independent current error signals of each power module 11 are generated by corresponding comparators. Specifically: Ierror1 = Iref1 - Isense1 Ierror2 = Iref2 - Isense2 Ierror3 = Iref3 - Isense3 Based on the calculated current error signals, it is determined in real time and automatically whether the corresponding power module needs to execute the current sharing regulation strategy according to whether the current error signal Ierror of each power module 11 is zero. Specifically: Normal situation, that is, no current sharing strategy needs to be executed: When the current error signals Ierror1, Ierror2, and Ierror3 of each power module 11 are all equal to zero or less than a set dead zone threshold, the current output of the three power modules 11 has accurately tracked their common current reference, that is, the balanced state has been reached. At this time, the system determines it as a normal situation and maintains the PWM duty cycle of each power module 11 unchanged.

[0082] Abnormal situation, that is, the current sharing strategy needs to be executed: When the current error signal Ierror of any one power module 11 is not equal to zero (or exceeds the dead zone threshold), it indicates that the current is unbalanced among multiple power modules 11. For example, if Ierror1 > 0, it means Isense1 < Iref1, that is, the actual current of the first power module is less than the target value, and its output power is low. The system immediately determines it as abnormal and triggers the current sharing strategy.

[0083] When it is determined that the current sharing strategy needs to be executed, the system will execute the duty cycle regulation strategy based on real-time calculation. The current error signals (Ierror1, Ierror2, Ierror3) of each power module are input into their respective independent current loop PI regulators. The current loop PI regulator operates on the current error signal and outputs the adjustment amount of the corresponding PWM duty cycle. The adjustment rule is as follows: When Ierror > 0: It means that the actual current value Isense of this power module is less than the target current value Iref, that is, the output power of this power module is insufficient. At this time, the current loop PI regulator will output an increasing control signal, resulting in an increase in the duty cycle of the PWM drive signal of the main power switch tube of this power module, so that this power module outputs more current to catch up with other power modules.

[0084] When Ierror < 0: It means that the actual current value Isense of this power module is greater than the target current value Iref, that is, the output power of this power module is too high. At this time, the current loop PI regulator will output a decreasing control signal, resulting in a decrease in the duty cycle of the PWM drive signal of the main power switch tube of this power module, so as to suppress the output current of this power module and wait for other power modules.

[0085] When Ierror = 0 (or enters a very small dead zone): it indicates that the current of the power module has accurately tracked the target current and is in a balanced state. The PI regulator maintains the output, and the duty cycle remains constant.

[0086] For example, when the system load undergoes a step change or when an imbalance in current between modules occurs due to temperature drift of component parameters, this imbalance will be immediately reflected in the feedback signal of the primary current and manifested as a change in the current error signal. The control system then dynamically adjusts the duty cycle of each phase according to the above rules, so that the system output current tends to be balanced again.

[0087] It should be noted that the sampling, calculation, judgment, and adjustment processes described above are executed cyclically in each PWM cycle, thus forming a continuous closed-loop control. This dynamic adjustment mechanism enables the system to respond in real time to various operating condition changes, including transient processes such as startup and sudden load changes, ensuring that high-precision current sharing is maintained even when there are inherent deviations in the parameters of each module.

[0088] Through the continuous operation of the above closed-loop control method, the embodiments of this application realize accurate, fast and adaptive current sharing control of multi-module parallel power supplies, effectively improving the stability, reliability and output performance of the system.

[0089] This application also proposes a current sharing control device for multi-module parallel power supplies, used to implement the current sharing control method for multi-module parallel power supplies described in the above embodiments. The specific implementation of this device can be varied.

[0090] In some embodiments, the control device may be specifically implemented as a functional module composed of software or firmware. Please refer to Figure 6, which is a functional module schematic diagram of a current sharing control device for a multi-module parallel power supply in an embodiment of this application. The current sharing control device 60 for the multi-module parallel power supply includes: a signal acquisition module 610, configured to acquire feedback signals characterizing the primary current of the transformer of each power module; and a duty cycle adjustment module 620, connected to the signal acquisition module 610, configured to independently adjust the duty cycle of the main power switch in the corresponding power module based on each feedback signal.

[0091] In some embodiments, the signal acquisition module 610 may be further configured to: acquire a mutual inductance secondary current proportional to the primary current of the transformer through a current transformer connected in series in the primary circuit of the power module; convert the mutual inductance secondary current into a feedback signal characterizing the primary current of the transformer; and adjust the duty cycle of the corresponding main power switch of the power module according to each feedback signal to perform current sharing control on the power module.

[0092] In some embodiments, the duty cycle adjustment module 620 may be further configured to sample the secondary current of each mutual inductor during the conduction of the clamping switch of the power module.

[0093] In some embodiments, the duty cycle adjustment module 620 may be further configured to: sample the total output voltage of the system, and generate a unified current reference signal based on the comparison result of the total output voltage and a preset voltage reference value; compare each sampled signal with the unified current reference signal to generate a current error signal for each power module; and adjust the duty cycle of the corresponding power module based on each current error signal.

[0094] In some embodiments, the signal acquisition module 610 may be further configured to: synchronously sample the primary current of the transformer of each power module at the duty cycle time corresponding to a preset ratio of the PWM cycle of each power module, and obtain the mutual inductance secondary current proportional to the primary current of the transformer.

[0095] This application also provides a hardware implementation of a current sharing control device for a multi-module parallel power supply. In some embodiments, the control device can be specifically implemented as a digital signal processor (DSP), a microcontroller unit (MCU), an application-specific integrated circuit (ASIC), or a control board containing programmable logic devices. Specifically, the control device includes a processor and a memory. The memory stores a computer program, which, when executed by the processor, implements the current sharing control method for a multi-module parallel power supply as provided in any embodiment of this disclosure. For example, the functions of the signal acquisition module 610 and the duty cycle adjustment module 620 can both be implemented by the processor executing the corresponding program instructions stored in the memory.

[0096] This control device (regardless of how it is implemented) has all the beneficial effects of the current sharing control method for multi-module parallel power supplies, such as achieving high-precision current sharing through direct, independent closed-loop control of the primary current, eliminating the need for an additional current sharing bus, and providing fast system dynamic response, etc., which will not be elaborated further here.

[0097] This application also proposes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method provided in any embodiment of this disclosure.

[0098] In the embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0099] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart illustrations and / or one or more block diagrams.

[0101] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0102] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0103] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0104] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0105] Computer-readable media include both permanent and non-permanent, removable and non-removable media, which can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient media, such as modulated communication signals and carrier waves.

[0106] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A current sharing control method for a multi-module parallel power supply, characterized in that, Includes the following steps: A feedback signal characterizing the primary current of the transformer in each power module is acquired, and the power modules are connected in parallel. Each feedback signal is compared with a common current reference signal to generate a current error signal for each power module. Based on the current error signal, the duty cycle of the main power switch of the corresponding power module is adjusted to perform current sharing control on the power module.

2. The method according to claim 1, characterized in that, The step of adjusting the duty cycle of the main power switch of the corresponding power module based on the current error signal to perform current sharing control on the power module includes: increasing the duty cycle of the main power switch of the corresponding power module when the current error signal is greater than a first threshold; decreasing the duty cycle of the main power switch of the corresponding power module when the current error signal is less than the first threshold; and keeping the duty cycle of the main power switch of the corresponding power module unchanged when the current error signal is equal to the first threshold.

3. The method according to claim 1, characterized in that, The method further includes: sampling the total output voltage of the multi-module parallel power supply system; comparing the total output voltage with a preset voltage reference value; generating a current amplitude command through voltage loop processing; and using the current amplitude command as the shared current reference signal.

4. The method according to claim 1, characterized in that, The step of obtaining the feedback signal characterizing the primary current of each power module connected in parallel includes: obtaining a mutual inductance secondary current proportional to the primary current of the transformer through a current transformer connected in series in the primary circuit of the power module; and converting the mutual inductance secondary current into the feedback signal characterizing the primary current of the transformer.

5. The method according to claim 4, characterized in that, During the conduction of the clamping switch of the corresponding power module, the feedback signal that converts the mutual inductor secondary current into a characterizing the transformer primary current is executed.

6. The method according to claim 5, characterized in that, At the duty cycle time corresponding to the preset ratio of the PWM cycle of the power module, the feedback signal that converts the mutual inductor secondary current into the primary current of the transformer is executed.

7. A current sharing control system for a multi-module parallel power supply, comprising multiple power modules connected in parallel, characterized in that, Also includes: A current detection and sampling circuit; a control unit, connected to the current detection and sampling circuit and each of the power modules, configured to: control the current detection and sampling circuit to acquire a feedback signal characterizing the transformer primary current of each power module; compare each feedback signal with a common current reference signal to generate a current error signal for each power module; and adjust the duty cycle of the main power switch of the corresponding power module based on the current error signal to perform current sharing control on the power module.

8. The system according to claim 7, characterized in that, The current detection and sampling circuit includes: multiple current transformers, each current transformer having its primary winding connected in series in the primary circuit of the transformer of the corresponding power module, and its secondary winding outputting a mutual inductance secondary current proportional to the primary current of the transformer; multiple sampling units, each sampling unit being connected to the secondary winding of one of the current transformers; and the control unit being configured to: during the conduction period of the clamping switch of the corresponding power module, control the sampling units to sample the secondary current signal generated by the current transformer corresponding to the power module, and convert the secondary current into a feedback signal characterizing the primary current.

9. A control device, characterized in that, It includes a processor and a memory, the memory storing a computer program that, when executed by the processor, implements the method as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 6.

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