Marine high-voltage power supply device and control method thereof

Abstract

The invention discloses a marine high-voltage power supply device and a control method thereof, and the device adopts an integrated hybrid topology and is formed by connecting a plurality of conversion modules with the same internal structure in series. Two Boost units and one LLC resonant conversion unit are integrated in each module to form a three-level structure, and the three-level structure jointly supplies power to a post-stage LLC, so that the traditional symmetric architecture that one Boost corresponds to one LLC is broken through, and the number of expensive magnetic elements is reduced. The method comprises two control strategies: one is master-slave voltage-sharing control with proportion limitation, and system oscillation is effectively prevented; and 2, based on double closed-loop control of a voltage outer loop and an independent current inner loop, rapid and static-error-free automatic voltage sharing is realized by using the current inner loop. According to the invention, through the same hardware platform, two output modes of parallel redundancy and independent multipath can be flexibly realized only by configuring output connection. According to the scheme, for high-voltage direct-current power supply of a new energy ship, device stress and system cost can be effectively reduced, and efficiency, reliability and electromagnetic compatibility are improved.

Description

A marine high-voltage power supply device and its control method Technical Field

[0001] This invention belongs to the field of high-voltage power supply technology for new energy ships, specifically relating to a marine high-voltage DC power conversion device and its control method. Background Technology

[0002] As new energy ships develop towards larger sizes and higher power consumption, their power systems are evolving from traditional low-voltage DC (e.g., 750V) to high-voltage DC (e.g., 1500V and above). High-voltage systems can significantly reduce current when transmitting the same power, thereby greatly reducing line losses (P_loss = I). 2 R), saving cable costs and weight, and improving system efficiency and power density.

[0003] However, marine high-voltage DC power supply systems face a series of severe challenges: 1. Device stress and cost issues: In a single high-voltage conversion topology, power switching devices directly bear the high voltage of the entire bus, which places stringent requirements on the voltage withstand level of the devices, resulting in high costs, difficulty in selection, and reduced reliability.

[0004] 2. Switching losses and electromagnetic interference issues: Traditional hard-switching converters have huge switching losses under high voltage and high power, and the rapid changes in current / voltage (high di / dt, dv / dt) will generate serious electromagnetic interference, making it difficult to meet the strict electromagnetic compatibility requirements of ships.

[0005] 3. Insufficient system redundancy and flexibility: Traditional power supply architectures cannot achieve flexible power expansion and multiple independent outputs without significantly increasing costs and complexity, and cannot meet the high reliability requirements of critical ship loads.

[0006] To address these challenges, existing technologies have introduced combined converter schemes such as input-series-output-parallel (ISOP). For example, the technology described in "Research on Multi-Module Input-Series-Output-Parallel System Based on Boost+LLC Resonant Converter" distributes the high-voltage input by connecting multiple independent "1 Boost + 1 LLC" modules in series. However, this scheme has significant shortcomings: the repetitive structure of each module leads to complexity in magnetic components (such as the high-frequency transformer in the LLC resonant converter) and the control system; furthermore, its modular parallel output structure is redundant and inflexible when pursuing multiple independent outputs. In addition, its LLC resonant converter typically operates in a fixed-frequency open-loop mode, making it difficult to maintain optimal soft-switching characteristics over a wide load range, resulting in decreased efficiency under light loads; its control strategy focuses on system-level voltage equalization, failing to fully consider the requirements for independent power supply to multiple loads, ripple suppression, and dynamic response under complex shipboard conditions.

[0007] Therefore, there is an urgent need for a marine high-voltage power supply solution with higher integration, more optimized topology, and more intelligent control, which can effectively reduce device stress while providing excellent output flexibility and system reliability. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing marine high-voltage power supply technology and provide a marine high-voltage power supply device with a compact topology, intelligent control, and high flexibility.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a marine high-voltage power supply device, comprising several power supply sub-modules with identical internal topologies. Each power supply sub-module includes a first Boost converter, a second Boost converter, and an LLC resonant converter. The first Boost converter includes a power transistor Q11, a diode D1, a resistor R2, and a capacitor C11. The second Boost converter includes a power transistor Q12, a diode D2, a resistor R3, and a capacitor C12. The collector (C) of the power transistor Q11 serves as the positive input terminal of the module and is connected to the anode of the diode D1. Its cathode is connected to one input terminal of the full-bridge circuit of the LLC resonant converter. The other input terminal is connected to the anode of diode D2, and its cathode serves as the negative input terminal of the module, connected to the emitter (E) of power transistor Q12. The emitter (E) of power transistor Q11 and the collector (C) of power transistor Q12 are connected to form an intermediate node. The intermediate node is connected to one end of the primary winding of a transformer through capacitor C17, and the other end is connected to the output midpoint of the full-bridge circuit. The secondary winding of the transformer is used as the power output through a rectifier and filter unit. Resistor R2 and capacitor C11 are connected in series and then connected across the collector (C) and emitter (E) of power transistor Q11. Resistor R3 and capacitor C12 are connected in series and then connected across the collector (C) and emitter (E) of power transistor Q12. The inputs of each power sub-module are connected in series to form a pre-amplifier boost circuit. The two input terminals of the pre-amplifier boost circuit are each connected to an external power source through an inductor.

[0010] The core of the aforementioned device lies in its innovative "N-Boost input series to M-LLC" integrated hybrid topology architecture (where N>M), breaking away from the traditional symmetrical modular thinking of "one boost corresponding to one LLC" in ISOP (input series, output parallel) systems. By connecting the inputs in series, the device distributes the total high input voltage across each boost unit, significantly reducing the voltage stress on each power switch (such as Q11, Q12). This allows for the use of commercially available devices with lower voltage ratings, lower costs, and faster switching speeds, rather than custom-made components, fundamentally solving the voltage-bearing problem of a single converter. Simultaneously, the integrated modular structure lays the foundation for flexible configuration and intelligent control.

[0011] In a preferred embodiment, the power supply submodule is configured with two modules, thereby forming four Boost converters. The specific architecture of "4Boost + 2 LLC" realizes the core idea of ​​this invention. Compared with the traditional "2 Boost + 2 LLC" ISOP scheme, it reduces the number of LLC resonant converters and their associated high-frequency transformers, resonant inductors, capacitors, and other magnetic components while achieving the same high-voltage input and power level. This reduces system cost, size, and weight, while achieving higher power density and system integration.

[0012] In a preferred embodiment, the output terminals of the rectifier and filter units corresponding to each power supply submodule are connected in parallel. This scheme enables power superposition and system redundancy backup. When the device is configured in this mode, it can provide a larger output current for a high-power load (such as a propulsion system), and when one power supply submodule fails, the remaining modules can continue to operate, ensuring the continuity of power supply and greatly improving the power supply reliability of critical loads on the ship. Alternatively, in another preferred embodiment, the output terminals of the rectifier and filter units corresponding to each power supply submodule are configured to be independent of each other, forming multiple outputs, realizing the flexibility of one set of hardware for multiple applications. By configuring the output connection method, multiple electrically isolated DC power supplies with independently settable voltage and power levels can be generated, thereby providing customized power supply for different equipment on board (such as propulsion systems, pulse loads, and precision instruments), solving the problems of single function and rigid system configuration of dedicated power supply equipment.

[0013] Secondly, the present invention provides a method for controlling the aforementioned marine high-voltage power supply device, the method including a voltage equalization control step for the front-stage boost circuit. Voltage equalization control provides a core control guarantee for stable operation of the asymmetric hybrid topology of the present invention, effectively preventing uneven voltage distribution in series units due to differences in component parameters, thereby avoiding the risk of damage to some components due to overvoltage and improving the overall reliability and lifespan of the system.

[0014] As a preferred embodiment, voltage equalization control can be implemented based on a single-voltage-loop control strategy of master-slave voltage equalization and proportional limitation. This includes: using the output voltage of the first Boost unit in the first power supply submodule as a reference, its error is used to generate a reference duty cycle signal via a PID controller; the difference between the output voltage of the corresponding Boost unit in other power supply submodules and the reference voltage is used to generate voltage equalization compensation signals via their respective PID controllers; the final PWM control signal of the Boost unit in each power supply submodule is generated by superimposing the reference duty cycle signal and the corresponding voltage equalization compensation signal, and the reference duty cycle signal occupies at least 80% of the dominant proportion in the final PWM control signal. By introducing a proportional limitation mechanism, the reference duty cycle signal of the master unit is limited to a dominant proportion (>80%), and the voltage equalization compensation signal of the slave unit is limited to a secondary proportion (<20%). This effectively prevents the multi-loop control system from experiencing global oscillations due to sampling disturbances or minor parameter differences in a single unit, greatly improving the system's stability and engineering practicality, making it easier to operate stably in complex marine conditions.

[0015] As another preferred embodiment, the voltage equalization control steps can also be implemented based on a dual closed-loop control strategy of a total voltage outer loop and independent current inner loops for each unit. This includes: sampling the total output voltage or representative voltage and comparing it with a set value; generating a total current command via a voltage outer loop PID regulator; equally distributing the total current command as the current setpoint for each Boost unit in each power supply submodule; and controlling the inductor current to track the allocated current command via an independent current inner loop PID regulator. Utilizing the fast response characteristics of the current inner loop, inherent, zero-steady-state-error dynamic voltage equalization is achieved. The voltage outer loop generates a common current command, and each independent current inner loop forces the inductor current of its unit to accurately track this command. Since the current in the series circuit is necessarily equal, according to power balance, each unit will automatically share the total input voltage equally. This method has extremely fast dynamic response and high voltage equalization accuracy. Furthermore, an auxiliary voltage equalization compensation step is included, comprising: sampling the output voltage of the Boost unit in each power supply submodule and calculating the difference between it and the reference voltage; and superimposing the compensation amount generated by PID calculation of the difference onto the output of the current inner loop PID regulator of the corresponding unit to correct the static voltage equalization error. By superimposing a fine voltage compensation loop on the fast current loop, the static voltage equalization error caused by circuit parameter asymmetry can be effectively corrected, achieving a combination of "coarse adjustment" and "fine adjustment," enabling the system to achieve both fast dynamic response and extremely high steady-state accuracy.

[0016] As a preferred embodiment, the method includes the following steps for frequency conversion and phase shift coordinated control of the LLC resonant converter unit: sampling the DC output voltage V_out of the LLC resonant converter unit; comparing V_out with the desired voltage reference V_ref, and outputting the resulting error signal as a main control command V_control via a voltage PID regulator; generating a corresponding switching frequency f_sw signal based on a preset frequency mapping relationship according to V_control, and simultaneously generating a corresponding phase shift angle φ signal based on a preset phase mapping relationship between V_control and V_control; and generating four PWM drive signals with dead time based on the switching frequency f_sw signal and the phase shift angle φ signal to control the four switching transistors in the full-bridge circuit of the LLC resonant converter unit. This scheme combines simple frequency conversion control with phase shift control. By coordinating the adjustment of the switching frequency and phase shift angle, it can optimize the soft-switching characteristics (zero-voltage turn-on) of the LLC over a wide input voltage range and a wide load range. This not only further improves the overall efficiency, especially under light load conditions, but also improves the dynamic response capability of the system and helps to suppress electromagnetic interference. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same components throughout the drawings.

[0018] In the accompanying drawings: Figure 1 shows a block diagram of the parallel redundant output mode circuit of the power supply device of the present invention; Figure 2 shows a block diagram of the independent multi-output mode circuit of the power supply device of the present invention; Figure 3 shows a flowchart of the single voltage loop control strategy of the Boost boost unit; Figure 4 shows a flowchart of the voltage and current dual closed-loop control strategy of the Boost boost unit; Figure 5 shows a block diagram of the frequency conversion and phase shift control strategy of the LLC resonant converter; Figure 6 shows a circuit diagram of the parallel redundant output mode of the power supply device of the present invention; Figure 7 shows a circuit diagram of the independent multi-output mode of the power supply device of the present invention. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0020] It should also be understood that the term “and / or” as used in exemplary embodiments of this disclosure refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0021] The marine high-voltage power supply device of the present invention adopts an innovative "N-Boost input series to M-LLC" integrated hybrid topology architecture (where N>M), including an input filter circuit, multiple series boost boost circuits, multiple LLC resonant converters, a high-frequency isolation transformer, a full-bridge rectifier circuit, and an output filter circuit connected in sequence.

[0022] Referring to Figures 1 and 2, taking a preferred embodiment of the present invention as an example, the front-end circuit is composed of four Boost converters (Boost converters 1, 2, 3, and 4) connected in series at their input sides to share the total high voltage input of the system. The back-end circuit includes two independent LLC resonant converters (LLC converters 1 and 2). The outputs of Boost converters 1 and 2 jointly power LLC converter 1, forming a power supply submodule. The outputs of Boost converters 3 and 4 jointly power LLC converter 2, forming another power supply submodule.

[0023] The two power supply submodules are electrically connected in series to withstand high voltage input, but their outputs (i.e., the outputs of LLC converter units 1 and 2) can be configured as parallel outputs (as shown in Figure 1) or independent multi-outputs (as shown in Figure 2) according to system requirements.

[0024] The implementation methods of each module unit are as follows: 1.1 Multiple Series-Connected Boost Circuits (Refer to Figures 6 and 7). This part consists of N (N≥4) identical Boost units connected in series. Each Boost unit includes a power switch (such as a MOSFET or IGBT), a freewheeling diode, a capacitor, and a resistor. Every two Boost units share the primary winding of a transformer as an inductor. The low-voltage DC input (such as DC 750V) is filtered before being connected in series to each Boost unit. This series structure distributes the total high-voltage output pressure across each unit, significantly reducing the voltage withstand requirements of individual power devices.

[0025] 1.2 LLC Resonant Converter and Transformer Isolation Unit: Every two boost units are connected to an intermediate DC bus voltage input to the LLC resonant converter, forming a three-level power conversion unit that is connected in series or parallel with another identical three-level unit for output. Taking the topology of the first power submodule shown in the figure as an example, the module includes a first boost unit Unit1, a second boost unit Unit2, and an LLC resonant converter unit 1. Unit1 includes a power transistor Q11, a diode D1, a resistor R2, and a capacitor C11. Unit2 includes a power transistor Q12, a diode D2, a resistor R3, and a capacitor C12. The collector (C) of the power transistor Q11 serves as the positive input terminal of the module and is connected to the anode of the diode D1. Its cathode is connected to one input terminal of the full-bridge circuit of the LLC resonant converter unit. The other input terminal of the full-bridge circuit... The input terminal is connected to the anode of diode D2, and its cathode serves as the negative input terminal of the module, connected to the emitter (E) of power transistor Q12. The emitter (E) of power transistor Q11 and the collector (C) of power transistor Q12 are connected to form an intermediate node. This intermediate node is connected to one end of the primary winding of a transformer via capacitor C17, and the other end is connected to the output midpoint of the full-bridge circuit. The secondary winding of the transformer is rectified and filtered by a rectifier unit as the power output. Resistor R2 and capacitor C11 are connected in series across the collector (C) and emitter (E) of power transistor Q11, and resistor R3 and capacitor C12 are connected in series across the collector (C) and emitter (E) of power transistor Q12. The inputs of each converter module are connected in series to form a pre-stage boost circuit. The two input terminals of the pre-stage boost circuit are each connected to an external power supply via a common inductor. Compared to the topology of one boost unit corresponding to one LLC resonant unit in the paper "Research on Multi-Module Input Series Output Parallel System Based on Boost+LLC Resonant Converter", this structure can reduce the number of LLC resonant units, improve system stability, and reduce device costs. The LLC resonant network consists of a resonant inductor, a resonant capacitor, and a transformer magnetizing inductance. The LLC converter operates near its quasi-resonant frequency, achieving zero-voltage turn-on of the power switches and zero-current turn-off of the rectifier diodes, i.e., "soft switching." Its output undergoes electrical isolation and voltage regulation via a high-frequency isolation transformer before being rectified by a full-bridge rectifier circuit.

[0026] 1.3 Intelligent Control Strategy The control method includes control strategies for multiple series-connected boost circuits in the front stage, specifically two core control strategies for the multi-phase series-connected boost circuits in the front stage. These are crucial for ensuring the stable operation of the improved topology: 1.3.1 Single Voltage Loop Control Strategy Based on Master-Slave Voltage Equalization and Proportional Limitation (as shown in Figure 3): The innovation of this strategy lies in the introduction of a proportional limitation mechanism. The output voltage V1 of boost unit 1 is used as the reference and main feedback. Its error is processed by a PID controller to generate a reference duty cycle (Vpidout1), which dominates the final PWM (typically >80%). The voltage differences between other units and V1 are processed by PID to generate voltage equalization compensation signals (Vpidout2, 3, 4), whose outputs are limited to a smaller proportion (typically <20%). The final PWM signal is generated by superimposing the reference signal and the compensation signal (e.g., Pwm2 = Vpidout1 + Vpidout2). This proportional limitation effectively prevents global oscillations caused by sampling disturbances in a single unit, greatly improving the stability and reliability of the system.

[0027] 1.3.2 Dual Closed-Loop Control Strategy Based on Total Voltage Outer Loop and Independent Current Inner Loops for Each Unit (as shown in Figure 4): The innovation of this strategy lies in utilizing the fast response of the current inner loops to achieve automatic and forced voltage equalization. The voltage outer loop outputs a total current command, which is simultaneously and equally distributed to the four independent current inner loops. Each current inner loop forces the inductor current of its unit to precisely track this common command. Since the current in the series circuit is necessarily equal, according to power balance, each unit will automatically and equally share the total input voltage. This method achieves inherent, zero steady-state error dynamic voltage equalization with extremely fast response speed, making it the optimal control scheme of this invention.

[0028] The detailed design method is as follows: Scheme 1: Single voltage loop control strategy based on master-slave voltage equalization (corresponding to Figure 3). This strategy is suitable for scenarios with moderate dynamic response requirements and a simple control structure.

[0029] Control principle: Set a desired total output voltage value Vset. First, compare the actual output voltage V1 of boost unit 1 with Vset, and generate a reference duty cycle signal (Vpidout1) through a voltage PID controller (Vpid1).

[0030] Voltage equalization is achieved by comparing the output voltage V1 of boost unit 1 with the output voltages V2, V3, and V4 of other units, calculating the differences (V2-V1, V3-V1, V4-V1). These difference signals are then fed into their respective voltage PID controllers (Vpid2, Vpid3, Vpid4) to generate voltage equalization compensation signals. The reference duty cycle signal (Vpidout1) and the voltage equalization compensation signals (Vpidout2, Vpidout3, Vpidout4) are subject to certain proportional restrictions. The reference duty cycle signal (Vpidout1) is generally greater than 80%, while the voltage equalization compensation signals (Vpidout2, Vpidout3, Vpidout4) are less than 20%, used to adjust the system error of the hardware parameters of each boost unit. This proportional restriction ensures the voltage equalization effect of the system, improves system stability, and reduces the risk of system runaway.

[0031] PWM Generation: Ultimately, the PWM control signal for each unit is generated by superimposing the reference duty cycle signal and its respective voltage equalization compensation signal. That is: Pwm1 = Vpidout1 (Unit 1 acts as the master unit) Pwm2 = Vpidout1 + Vpidout2 (output based on Unit 1 as the reference, while superimposing the difference between the voltage equalization compensation signals (V2-V1)) Pwm3 = Vpidout1 + Vpidout3 (output based on Unit 1 as the reference, while superimposing the difference between the voltage equalization compensation signals (V3-V1)) Pwm4 = Vpidout1 + Vpidout4 (output based on Unit 1 as the reference, while superimposing the difference between the voltage equalization compensation signals (V4-V1)) Through this "master-slave" structure, the system stabilizes the total output voltage while automatically forcing the output voltage of each series unit to follow the master unit, achieving static voltage equalization.

[0032] Option 2: A dual closed-loop control strategy based on the outer loop of total voltage and the inner loop of current for each unit (corresponding to Figure 4). This strategy is suitable for scenarios with extremely high requirements for system dynamic response speed, stability and current sharing accuracy.

[0033] Control principle: 1) Voltage outer loop: The sampled total output voltage (or the voltage V1 of unit 1 as a representative) is compared with the set value Vset, and a total current command (Vpidout1) is generated by the voltage PID controller (Vpid1). This current command represents the total inductor current required to maintain the stability of the output voltage.

[0034] 2) Inner Current Loop: The total current command (Vpidout1 / N) is used as the current setpoint for each Boost unit. Simultaneously, the inductor current (I1, I2, I3, I4) of each Boost unit is sampled. Each unit has its own independent current PID controller (Ipid1, Ipid2, Ipid3, Ipid4), which, by adjusting the PWM duty cycle of each unit, forces the actual inductor current of each unit to track the total current / N command quickly and accurately.

[0035] Because the current flowing through each series unit is forced to be equal, according to the power balance principle, as long as the circuit parameters are symmetrical, each unit automatically shares the total output voltage equally, thus achieving natural voltage equalization. This method has inherent balancing capabilities and extremely fast dynamic response.

[0036] Furthermore, an auxiliary voltage equalization compensation step is set up: the output voltage of the Boost boost unit in each conversion module is sampled, and the difference between it and the reference voltage is calculated; the compensation amount generated by the difference after PID calculation is superimposed on the output of the current inner loop PID regulator of the corresponding unit to correct the static voltage equalization error.

[0037] Both strategies require the implementation of PWM multi-phase phase shifting technology: the PWM drive signals of the four Boost units are interleaved with specific phase differences (in the drive design of PWM1, PWM2, PWM3, and PWM4, PWM1 and PWM2 are required to be out of phase by 90 degrees, PWM3 and PWM4 by 90 degrees; PWM1 and PWM3 are required to be out of phase by 180 degrees, and PWM2 and PWM4 by 180 degrees) to reduce ripple.

[0038] 1.3.3 Control of the LLC Converter The LLC resonant converter adopts frequency conversion phase-shift control. Its design advantage lies in "one voltage loop, simultaneously outputting two control quantities: frequency and phase shift". By precisely adjusting the switching frequency, its voltage gain is controlled, achieving precise and efficient regulation of the output. At the same time, the phase-shift control further optimizes the soft-switching characteristics, reduces circulating current loss, and maintains good efficiency under light load conditions.

[0039] In steady-state operation: The system primarily relies on frequency converter control to stabilize the output voltage. The controller finds a suitable switching frequency f_sw so that the LLC gain precisely satisfies the input-output relationship. Simultaneously, under light load conditions, by introducing an appropriate phase shift angle, circulating current energy can be reduced, soft-switching characteristics can be maintained, and efficiency drops can be prevented. When the load or input voltage changes suddenly, the phase shift angle can be quickly adjusted, working in conjunction with frequency regulation to accelerate the system's dynamic response speed.

[0040] Specific implementation: Referring to Figure 5, the control of the LLC converter is implemented by a digital signal processor (DSP).

[0041] The DSP's ADC module samples the output voltage V_out.

[0042] Calculate the voltage error V_ref - V_out, and obtain the control quantity V_control using a voltage PID algorithm.

[0043] The DSP internally queries the required switching frequency value based on the preset mapping table (or calculation formula) between V_control and switching frequency f_sw, and configures the timer period register to generate the fundamental frequency.

[0044] At the same time, based on the preset frequency mapping relationship queried by V_control (or after independent phase-shifting PID calculation), the size of the phase shift angle φ is determined, and the phase offset register of the timer is configured.

[0045] The DSP's ePWM module automatically generates four drive signals with dead time based on the set frequency and phase. After being amplified by the driver chip, these signals control the power switching transistors of the LLC full bridge.

[0046] 1.3.4 Optional Implementation Plan Parallel Output Mode: As shown in Figures 1 and 6, the output terminals of multiple power supply modules can be connected in parallel. Through current sharing control technology, power capacity expansion and N+X redundancy backup of the system can be achieved, greatly improving power supply reliability.

[0047] Independent multi-output mode: As shown in Figures 2 and 7, a set of multi-phase series Boost circuits can power multiple independent LLC+ full-bridge rectifier units, generating multiple stable and isolated high-voltage DC outputs to power different equipment on board (such as propulsion systems, pulse loads, and precision instruments).

[0048] This invention aims to solve the following technical problems: 1. Solve the problems of high redundancy and high cost of traditional ISOP architecture: By breaking the fixed modular thinking of "one Boost corresponds to one LLC", an integrated hybrid topology of "multiple Boost inputs connected in series to power fewer LLCs" is created. While ensuring voltage equalization and reliability, the number of LLCs and their magnetic components is reduced, thereby reducing system cost and size.

[0049] 2. Solve the voltage equalization control problem of the front-end series Boost system: Provide two efficient and stable voltage equalization control strategies, especially the introduction of automatic current equalization in the inner current loop and master-slave voltage equalization method with proportional limit, to ensure that the system can work stably in both static and dynamic processes and avoid voltage equalization failure caused by parameter differences.

[0050] 3. Solve ripple and EMI problems in high-voltage and high-power applications: By combining PWM multi-phase phase-shifting technology with the soft-switching characteristics of the downstream LLC, ripple and electromagnetic interference are suppressed from both the source and the propagation path, meeting the power supply requirements of shipboard precision equipment.

[0051] 4. Solve the pain point of single system output mode: Through architectural design, the system can flexibly switch between parallel redundant output and independent multi-output modes without changing the main circuit topology, simply by configuring the output connection method of the subsequent LLC, which greatly improves the applicability and reliability of the system.

[0052] Compared to the existing paper "Research on Multi-Module Input Series Output Parallel System Based on Boost+LLC Resonant Converter", the ISOP system constructed by the Boost+LLC resonant converter described in that paper consists of 1# Boost and 1# LLC forming module 1, and 2# Boost and 2# LLC forming module 2. The inputs of 1# Boost and 2# Boost are connected in series, while the outputs of 1# LLC and 2# LLC are connected in parallel. Each ISOP system contains one Boost unit and one LLC unit. In contrast, based on engineering practice, this invention uses four Boost modules in each minimum unit. Two Boost modules are connected in series to form a three-level structure, which is then connected to an LLC unit for output. The third and fourth Boost modules form another three-level structure, which is then connected in series with the first three-level structure. The second three-level unit can be connected in parallel with the first three-level unit for output or in series for output. Furthermore, the paper only analyzes the basic method of PI controller plus lead compensator for system control, using independent control of a single Boost unit. This results in large output ripple, and when multiple levels are connected in parallel, multiple PID controllers are needed, leading to a large computational load. This invention patent emphasizes the control strategy for achieving master-slave pressure and current equalization. The control method and strategy are significantly different from those described in the paper, and have broader application value in engineering practice.

[0053] Compared with traditional marine high-voltage DC power supply systems, this invention has the following advantages: 1. Significantly reduces device stress and system cost: By connecting multiple Boost units in series, the high-voltage output task is decomposed, so that each power switch only bears 1 / N of the total output voltage. Commercial devices with lower withstand voltage ratings, lower cost, and faster switching speed can be selected, solving the problem of the stringent voltage withstand requirements of a single Boost circuit under high voltage.

[0054] 2. Improved Efficiency and Reduced Heat Loss: The introduction of the LLC resonant converter enables soft switching, fundamentally eliminating switching losses and associated voltage and current spikes. This results in extremely high overall system efficiency, especially under long-term shipboard operation, with significant energy savings and reduced pressure on heat dissipation design. Combined with the control method shown in Figure 5, this invention not only achieves basic voltage regulation for the LLC converter but also ensures efficient soft-switching characteristics across a wide input voltage range and load range through coordinated frequency and phase shift control, while also possessing excellent dynamic response and good light-load performance. This perfectly meets the requirements of the complex and ever-changing operating environment of shipboard power grids. It also reduces the number of LLC resonant transformers, lowering costs.

[0055] 3. The control method described in this invention is simple and easy to implement in engineering applications, thus improving control accuracy and reliability.

[0056] 4. Easy System Integration: This invention, through the same core topology, can achieve three operating modes—parallel redundant output, independent multi-channel output, and single-channel maximum power output—by only changing the control logic and electrical connections. A single power supply unit can meet the power supply needs of various loads with different voltage levels, power levels, and power quality requirements on new energy ships, achieving deep integration of the power supply system and saving shipboard space and overall costs.

[0057] Example 1: Application of Parallel Output Mode (corresponding to Figure 1) Referring to Figure 1, when ship propulsion systems and other applications require a single high-power supply and have extremely high reliability requirements, this device can operate in parallel output mode.

[0058] System configuration: Connect the outputs of two or more complete power supply modules (each module contains multiple series boosters in the front stage and LLC converters in the back stage) in parallel.

[0059] Control method: Each module independently controls its front-end Boost circuit (using the voltage and current dual closed-loop control strategy shown in Figure 4), while master-slave current sharing or democratic current sharing control algorithm is used between modules to ensure that each module shares the load current equally.

[0060] Advantages: This mode enables power expansion. More importantly, when one module fails, the remaining modules can continue to supply power, achieving N+1 redundancy, which greatly improves system reliability and is particularly suitable for critical shipboard loads with extremely high requirements for continuous power supply.

[0061] Example 2: Application of Independent Multi-output Mode (corresponding to Figure 2) Referring to Figure 2, when the ship needs to supply power to different types of equipment, this device can operate in independent multi-output mode.

[0062] Configuration method: All Boost units in the front stage are controlled by a common voltage loop, working together to boost the input voltage to a preset, higher intermediate bus voltage (e.g., DC1800V). This common bus powers multiple independent LLC conversion channels.

[0063] Independent control for each channel: Each LLC converter channel is independently controlled. For example, LLC converter 1 can be set to output DC1500V to power the propulsion system; LLC converter 2 can be independently set to output DC1000V to power deck auxiliary equipment.

[0064] Advantages: Each output channel is electrically isolated, so drastic fluctuations in the load of one channel will not affect other channels, making it particularly suitable for powering mixed loads with different power quality requirements.

[0065] Example 3: Implementation of the control strategy (corresponding to Figures 3 and 4) The core of the control strategy of this invention is executed by a digital signal processor (DSP) or a high-end microcontroller (MCU).

[0066] 1) When using single voltage loop control (Figure 3): The ADC module periodically samples the output voltages V1, V2, V3, V4 of each Boost unit.

[0067] The CPU calculates Vpid1(Vset, V1) and limits its output to a reasonable range.

[0068] Meanwhile, the CPU performs parallel computations on Vpid2(V1, V2-V1), Vpid3(V1, V3-V1), and Vpid4(V1, V4-V1).

[0069] Finally, calculate Pwm1 = Vpidout1; Pwm2 = Vpidout1 + Vpidout2; Pwm3 = Vpidout1 + Vpidout3; Pwm4 = Vpidout1 + Vpidout4.

[0070] The calculated Pwm1-Pwm4 values ​​are written into the duty cycle register of the PWM generator to drive the switching transistors of each Boost unit.

[0071] 2) When using voltage and current dual closed-loop control (Figure 4): the ADC module synchronously samples the total output voltage (or V1) and the inductor currents I1, I2, I3, I4 of each unit.

[0072] The CPU performs the outer loop voltage calculation: Vpidout1 = Vpid1(Vset, V1). This value is used as the total current instruction.

[0073] Key steps: The CPU executes four current inner loop calculations in parallel: Ipidout1 = Ipid1(Vpidout1 / 4, I1) Ipidout2 = Ipid2(Vpidout1 / 4, I2) Ipidout3 = Ipid3(Vpidout1 / 4, I3) Ipidout4 = Ipid4(Vpidout1 / 4, I4) Calculate the equalization compensation amount: Vpidout2 = Vpid2(V1, V2-V1), Vpidout3 = Vpid3(V1, V3-V1), Vpidout4 = Vpid4(V1, V4-V1).

[0074] The final PWM signal is synthesized as follows: Pwm1 = Ipidout1; Pwm2 = Ipidout2 + Vpidout2; Pwm3 = Ipidout3 + Vpidout3; Pwm4 = Ipidout4 + Vpidout4.

[0075] The advantages of dual closed-loop control: When the load suddenly increases, causing the output voltage V1 to drop, the voltage loop output Vpidout1 (current command) will increase rapidly. This increased command will simultaneously act on all four current loops, forcing all Boost units to synchronously and quickly increase the inductor current to prevent the voltage drop. The dynamic response speed is extremely fast, and the current consistency between units is guaranteed. The figure also shows the optional voltage equalization compensation circuit (Vpid2-Vpid4), whose output is superimposed on the current loop output for fine voltage adjustment.

[0076] Example 4: Frequency Conversion and Phase Shift Control Strategy for LLC Resonant Converter (corresponding to Figure 5) As shown in Figure 5, this control strategy aims to achieve high efficiency and high precision output of the LLC converter. Its core lies in the combination of frequency adjustment and phase shift.

[0077] Control loop configuration: outer voltage loop (voltage regulator loop): sampling: sampling the DC output voltage V_out of the LLC converter.

[0078] Comparison and Adjustment: The sampled value V_out is compared with the desired voltage reference V_ref, and the resulting error signal is fed into a voltage PID regulator.

[0079] Output command: The output signal V_control of the voltage PID regulator serves as the main control command, comprehensively reflecting the deviation of the output voltage. This command is used to control both the switching frequency and the phase shift angle.

[0080] Frequency control channel: A portion of the V_control signal is fed into a voltage-controlled oscillator (VCO) or a frequency generator implemented by a digital controller (such as a DSP).

[0081] This module linearly converts the V_control signal into a specific switching frequency f_sw. The mapping is typically as follows: when a higher output voltage is needed (V_control increases), f_sw decreases towards a frequency below the resonant frequency f_r (to increase the LLC gain); and vice versa. The generated f_sw signal serves as the base clock, producing two complementary raw PWM waveforms, PWM_A and PWM_B, with dead time.

[0082] Phase Shift Control Channel: The V_control signal serves as the phase shift control signal, Phase_Shift_Control. A phase shift controller receives the basic PWM waves PWM_A and PWM_B, and generates an adjustable phase shift angle φ by mapping according to the magnitude of the Phase_Shift_Control signal.

[0083] Finally, four drive signals are output, which drive the four switches (Q21, Q22, Q23, Q24; Q25, Q26, Q27, Q28) in the LLC full-bridge or half-bridge circuit, respectively. These four signals are complementary to each other, and there is a fixed dead time between the upper and lower switches of the same bridge arm, while there is a controlled phase difference φ between the drive signals of bridge arm A and bridge arm B.

[0084] Example 5: Implementation Scheme for Power Expansion and System Redundancy (corresponding to Figures 6 and 7) Figure 6 shows two identical power modules (Module 1, Module 2) connected in parallel. Each module includes its independent front-end multi-phase series Boost converter circuit (taking a four-unit example) and a rear-end LLC resonant converter and rectification and filtering circuit.

[0085] The inputs of the two modules are connected in parallel to a low-voltage DC source (such as a ship's battery). Their outputs are directly connected in parallel to supply power to a high-voltage DC load (such as a propulsion motor).

[0086] The two modules work collaboratively through inter-module current sharing control, evenly distributing the total load power. When one module fails, the other can continue operating independently, ensuring uninterrupted power supply and achieving "N+1" redundancy backup, significantly improving the reliability of the ship's power supply system. This solution is also easily expandable to connect more modules in parallel to meet greater power demands.

[0087] Figure 2 is a block diagram of the independent multi-output mode circuit of the power supply device of the present invention, and Figure 7 is a circuit diagram of the independent multi-output mode of the power supply device of the present invention.

[0088] As shown in Figure 7, this embodiment illustrates a scheme with one input and multiple independent outputs. Multiple (three shown in the figure) boost units (Boost Unit 1, Boost Unit 2, Boost Unit 3...) are connected in parallel for input and series for output to form a unified, stable high-voltage intermediate DC bus. The bus supplies power to multiple completely independent downstream conversion channels, each with potentially different parameters. Each channel includes an LLC converter unit (e.g., LLC Converter Unit 1, LLC Converter Unit 2...) and a rectifier / filter unit (e.g., Rectifier / Filter Unit 1, Rectifier / Filter Unit 2...). Each downstream channel generates an independent, electrically isolated DC output (Output 1, Output 2...). Different voltage and power levels can be set for each output by controlling the parameters of its respective LLC converter. For example, Output 1 can provide DC 1500V for an electric propulsion system, Output 2 can provide DC 1000V for deck machinery, and Output 3 can provide high-quality DC 800V power for precision instruments. The output channels do not interfere with each other, enabling customized power supply for different loads and enhancing the flexibility of the system design.

[0089] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A marine high-voltage power supply device, characterized in that: The system comprises several power supply sub-modules with identical internal topologies. Each sub-module includes a first Boost converter, a second Boost converter, and an LLC resonant converter. The first Boost converter includes a power transistor Q11, a diode D1, a resistor R2, and a capacitor C11. The second Boost converter includes a power transistor Q12, a diode D2, a resistor R3, and a capacitor C12. The collector (C) of the power transistor Q11 serves as the positive input terminal of the module and is connected to the anode of the diode D1. Its cathode is connected to one input terminal of the full-bridge circuit of the LLC resonant converter. The other input terminal of the full-bridge circuit is connected to the anode of the diode D2, and its cathode serves as the positive input terminal of the module. The negative input terminal of the module is connected to the emitter (E) of power transistor Q12. The emitter (E) of power transistor Q11 is connected to the collector (C) of power transistor Q12 to form an intermediate node. The intermediate node is connected to one end of the primary winding of a transformer through capacitor C17, and the other end is connected to the output midpoint of the full-bridge circuit. The secondary winding of the transformer is used as the power output through a rectifier and filter unit. Resistor R2 and capacitor C11 are connected in series and then connected across the collector (C) and emitter (E) of power transistor Q11. Resistor R3 and capacitor C12 are connected in series and then connected across the collector (C) and emitter (E) of power transistor Q12. The inputs of each power sub-module are connected in series to form a pre-amplifier boost circuit. The two input terminals of the pre-amplifier boost circuit are each connected to an external power source through an inductor.

2. The marine high-voltage power supply device according to claim 1, characterized in that, The power supply submodule is configured in two ways to form four Boost boost units.

3. The marine high-voltage power supply device according to claim 1, characterized in that, The output terminals of the rectifier and filter units corresponding to each power supply submodule are connected in parallel.

4. The marine high-voltage power supply device according to claim 1, characterized in that, The output terminals of the rectifier and filter units corresponding to each power supply submodule are independent of each other to form multiple outputs.

5. A method for controlling a marine high-voltage power supply device as described in any one of claims 1 to 4, characterized in that, This includes a voltage equalization control step for the preceding boost circuit.

6. The method according to claim 5, characterized in that, The voltage equalization control steps are implemented based on a single-voltage loop control strategy of master-slave voltage equalization and proportional limitation, including: using the output voltage of the first Boost unit in the first power supply submodule as a reference, and generating a reference duty cycle signal by the error of the first Boost unit via a PID regulator; generating voltage equalization compensation signals by the difference between the output voltage of the corresponding Boost unit in other power supply submodules and the reference voltage via their respective PID regulators; the final PWM control signal of the Boost unit in each power supply submodule is generated by superimposing the reference duty cycle signal and the corresponding voltage equalization compensation signal, and the reference duty cycle signal occupies at least 80% of the dominant proportion in the final PWM control signal.

7. The method according to claim 5, characterized in that, The voltage equalization control steps are implemented based on a dual closed-loop control strategy consisting of a total voltage outer loop and independent current inner loops for each unit. This includes: sampling the total output voltage or representative voltage and comparing it with a set value; generating a total current command via a voltage outer loop PID regulator; distributing the total current command equally as the current setpoint for the Boost unit in each power supply submodule; and controlling the inductor current to track the allocated current command via an independent current inner loop PID regulator.

8. The method according to claim 7, characterized in that, When performing the voltage equalization control step, an auxiliary voltage equalization compensation step is also included: sampling the output voltage of the Boost boost unit in each power supply submodule and calculating the difference between it and the reference voltage; the compensation amount generated by the difference after PID calculation is superimposed on the output of the current inner loop PID regulator of the corresponding unit to correct the static voltage equalization error.

9. The method according to claim 5, characterized in that, The method includes the following steps for frequency conversion and phase shift coordinated control of the LLC resonant converter unit: sampling the DC output voltage V_out of the LLC resonant converter unit; comparing V_out with the desired voltage reference V_ref, and outputting the resulting error signal as a main control command V_control via a voltage PID regulator; generating a corresponding switching frequency f_sw signal based on a preset frequency mapping relationship according to V_control, and simultaneously generating a corresponding phase shift angle φ signal based on V_control and a preset phase mapping relationship; and generating four PWM drive signals with dead time based on the switching frequency f_sw signal and the phase shift angle φ signal to control the four switching transistors in the full-bridge circuit of the LLC resonant converter unit.

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