An interface box power supply system and control method for an ocean observatory network

Abstract

The application discloses a kind of for sea bottom observation network's adapter box power supply system and control method, belong to sea bottom observation equipment power supply technical field.The system includes front ISOP isolation type DC / DC converter, rear stage voltage stabilizing DC / DC converter and reverse feedback energy DC / DC converter;Front ISOP isolation type DC / DC converter adopts multiple module input series output parallel structure, input end is connected sea bottom DC transmission cable system;Rear stage voltage stabilizing DC / DC converter provides stable electric energy for observation instrument, and reverse feedback energy DC / DC converter feeds back excess energy to DC transmission cable system.The application realizes submodule input voltage-sharing control by two-way voltage comparison algorithm, adjusts bus voltage in conjunction with double-mode power feedback control, adopts bus voltage feedforward double closed loop control strategy to stabilize output voltage, with wide input voltage and high fault tolerance, can improve the reliability and energy transmission efficiency of sea bottom observation network power supply system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply for seabed observation equipment, and particularly relates to a junction box power supply system for a seabed observation network and a control method. BACKGROUND

[0002] In recent years, with the development of offshore new energy technology and the implementation of the national energy security strategy, the seabed observation network not only undertakes the task of seabed observation, but also meets the demand of offshore new energy power station for power transmission. The traditional seabed observation network is limited by the step-down ratio and power transmission efficiency of the junction box power supply, and usually adopts a lower cable voltage, which can only meet the power demand of low-voltage, small-power and small-range seabed observation instruments. When large-power offshore new energy power transmission is carried out, a large amount of power will be lost. Therefore, it is of great significance to design a junction box power supply with high input voltage, large power and high efficiency for improving the cable voltage of the seabed observation network for offshore large-power power transmission.

[0003] At present, most of the junction box power supplies suitable for the seabed observation network adopt a two-stage junction box scheme. The main junction box converts the seabed observation network cable voltage into a direct current low voltage, and the secondary junction box converts the direct current low voltage into a conventional underwater scientific instrument working voltage. However, the existing seabed observation network junction box design scheme has the following shortcomings:

[0004] 1. The main junction box mostly adopts an input series output parallel (ISOP) structure to improve the input voltage of the junction box. However, there is a voltage equalization problem in each module of the ISOP structure, which may cause the voltage of a single sub-module to soar in actual use, resulting in short circuit of the power device of the sub-module.

[0005] 2. The main junction box usually adopts open-loop control. However, the output voltage of the isolated DC / DC converter may soar when the load is light, which may cause the input voltage of the secondary junction box to be too high, resulting in breakdown of the secondary junction box.

[0006] 3. The two-stage junction box design has a direct current low voltage in the middle stage, and the introduction of the direct current low voltage cable increases the power transmission loss, which is not conducive to offshore new energy large-power power transmission. The multi-module design increases the equipment maintenance cost. SUMMARY

[0007] The problem to be solved by the present application is to provide a junction box power supply system for a seabed observation network, which has a wide input voltage and high fault tolerance capability, and can improve the reliability and energy transmission efficiency of the power supply system of the seabed observation network.

[0008] The present application adopts the following technical scheme: a junction box power supply system for a seabed observation network, the topological structure of which comprises: a front-stage ISOP isolated DC / DC converter, a rear-stage voltage-stabilized DC / DC converter and a reverse energy feedback DC / DC converter.

[0009] The front-stage ISOP isolation type DC / DC converter has an input end connected to a submarine observation network DC power cable system and an output end being a DC low-voltage bus; the front-stage ISOP isolation type DC / DC converter comprises a plurality of input series output parallel ISOP isolation type DC / DC converter sub-modules;

[0010] The back-stage voltage-stabilizing DC / DC converter has an input end connected to the output end of the ISOP isolation type DC / DC converter and an output end connected to a submarine observation instrument power supply port.

[0011] The reverse feedback energy DC / DC converter has an input end connected to the output end of the ISOP isolation type DC / DC converter and an output end connected back to the DC power cable system.

[0012] The technical scheme of the application further comprises a control method for the adapter box power supply system of the submarine observation network, which is applied to the adapter box power supply system and comprises the following steps:

[0013] S1, voltage equalization control is adopted for each DC / DC converter sub-module in the front-stage ISOP isolation type DC / DC converter, the maximum input voltage of each DC / DC converter sub-module is obtained through a bidirectional voltage comparison method, and the working state of each DC / DC converter sub-module is determined.

[0014] S2, output voltage stabilizing control is performed on the back-stage voltage-stabilizing DC / DC converter, a bus voltage feedforward double closed loop control strategy is adopted for voltage-current double closed loop control, an inductor current reference value is generated from an output voltage error through a voltage outer loop to obtain an inductor current error, an output signal is generated from the inductor current error through a current inner loop, a feedforward compensation channel output signal is executed for feedforward correction, and the signal after the feedforward correction is output to a PWM / PFM modulator to stabilize the output voltage.

[0015] S3, the reverse feedback energy DC / DC converter is controlled based on the DC low-voltage bus voltage, a dual-mode control method of a power closed loop control mode and a voltage-power double closed loop control mode is adopted, the control mode is switched through a hysteresis comparison strategy, and excess energy is fed back to the DC power cable to adjust the DC low-voltage bus voltage.

[0016] Preferably, in the front-stage ISOP isolation type DC / DC converter, each DC / DC converter sub-module adopts a ring communication topology, each sub-module only establishes a communication link with two adjacent sub-modules, the maximum input voltage of each DC / DC converter sub-module is obtained through bidirectional comparison, and the specific steps comprise:

[0017] In the downlink comparison stage, the first sub-module transmits the input voltage of the module as a downlink maximum value to the second sub-module, and the subsequent sub-modules compare the downlink received values V RXDAfter inputting the voltage value of this module, transfer the larger value downward;

[0018] Upward comparison stage: The last-stage sub-module transfers the input voltage of this module as the upward maximum value to the previous stage. The previous-stage sub-modules sequentially compare the upward received value V RXU After inputting the voltage value of this module, transfer the larger value upward;

[0019] Maximum value determination stage: Each sub-module compares the received upward and downward maximum values, and takes the larger value as the maximum input voltage of each DC / DC converter sub-module.

[0020] Furthermore, the voltage equalization control method for each DC / DC converter sub-module specifically includes:

[0021] Threshold voltage generation: Multiply the maximum input voltage by the corresponding proportionality coefficient k1 (0 < k1 < 1) to obtain the normal operating voltage threshold of the sub-module;

[0022] Operating state selection: If the input voltage of the sub-module is greater than or equal to the normal operating voltage threshold of the sub-module, the sub-module operates normally; if the input voltage of the sub-module is less than the normal operating voltage threshold of the sub-module, the duty cycle is reduced by ΔD. If the input voltage of the sub-module is still lower than the threshold voltage after the duty cycle is reduced, the sub-module is turned off.

[0023] Preferably, the post-stage regulated DC / DC converter adopts a bus voltage feedforward double closed-loop control strategy, which specifically includes:

[0024] Sampling unit: Sample the DC bus voltage V bus , the inductor current I L of the post-stage regulated DC / DC converter, and the output voltage V o , and subtract the output voltage V ref from the reference voltage V o to obtain the output voltage error;

[0025] Voltage-current double closed-loop: The voltage outer loop generates the inductor current reference value I ref through the first PI controller for the output voltage error. Subtract the inductor current sampling value I ref from the inductor current reference value I L to obtain the inductor current error. The current inner loop generates the d' signal through the second PI controller for the inductor current error;

[0026] Feedforward compensation path: Through the DC bus voltage sampling value V bus , perform a feedforward correction operation d = K·d' / V bus on the output signal of the second PI controller, where K is the feedforward gain coefficient, and finally output it to the PWM / PFM modulator.

[0027] Preferably, the reverse energy-fed DC / DC converter adopts a dual-mode control method, and the specific steps include:

[0028] S5.1. Reference voltage setting: Determine the ideal DC low-voltage bus voltage value V bus_ref ;

[0029] S5.2. Threshold voltage calculation: Multiply the ideal DC bus voltage value V bus_ref by the corresponding proportionality coefficients k2 and k3 (1 < k2 < k3 < 2) to obtain the power feedback voltage threshold V bus_th and the dual-loop control voltage threshold V bus_max respectively;

[0030] S5.3. During the rising process of the DC low-voltage bus voltage, if V bus_th < V bus < V bus_max , the reverse energy-fed DC / DC converter enables the power closed-loop control mode. If V bus ≥ V bus_max , the reverse energy-fed DC / DC converter switches to the voltage-power dual closed-loop control mode.

[0031] Furthermore, the control mode of the reverse energy-fed DC / DC converter is switched through a hysteresis comparison strategy. During the falling process of the DC low-voltage bus voltage, when the DC low-voltage bus voltage drops from higher than V bus_max to between (V bus_th , V bus_max ), the voltage-power dual closed-loop control mode is maintained; when the DC low-voltage bus voltage continues to drop below V bus_th , the reverse energy-fed DC / DC converter is turned off.

[0032] Furthermore, the power closed-loop control loop of the reverse energy-fed DC / DC converter includes:

[0033] Power sampling unit: It consists of DC bus voltage sampling, reverse energy-fed DC / DC converter input current sampling, a multiplier, and a low-pass filter. The reverse energy-fed DC / DC converter input current sampling value I infb is signal-connected to the input end of the low-pass filter, the output end of the low-pass filter is connected to the first input end of the multiplier, the DC bus voltage sampling value V bus is connected to the second input end of the multiplier, and the output end of the multiplier is the output end of the power sampling unit, which is the power sampling value;

[0034] Error adjustment unit: it is constituted by first subtracter and third PI controller, input power reference value is connected first subtracter positive input end, power sampling unit output end is connected first subtracter negative input end, and first subtracter output end is connected third PI controller input end;

[0035] PWM / PFM modulation unit: third PI controller output end is connected PWM / PFM modulator input end, and PWM / PFM modulator output end is connected reverse feedback energy DC / DC converter control end.

[0036] Further, the voltage-power double closed loop control mode loop of reverse feedback energy DC / DC converter is superimposed on the basis of power closed loop control voltage outer loop:

[0037] Voltage outer loop is constituted by second subtracter and fourth PI controller, and ideal DC bus voltage value V bus_ref As voltage reference value is connected second subtracter negative input end, DC bus voltage sampling value is connected second subtracter positive input end, second subtracter output end is connected fourth PI controller input end, and the output of fourth PI controller is used as power reference value to provide power reference benchmark for inner loop, and the cascade control structure is formed.

[0038] Compared with the prior art, the above technical scheme has the following technical effects:

[0039] 1、The power supply system of the adapter box of the application, through the front-stage ISOP isolation type DC / DC converter, is connected to the submarine DC power cable system, through the rear-stage voltage stabilizing DC / DC converter, stable electric energy is provided for the observation instrument, through the reverse feedback energy DC / DC converter, the excess energy is fed back to the DC power cable system, has wide input voltage and high fault tolerance capability, and can improve the reliability and energy transmission efficiency of the submarine observation network power supply system.

[0040] 2、The power supply system of the adapter box of the application, through the bidirectional voltage comparison algorithm, realizes the input voltage equalization control of the sub-module, combines the dual-mode power feedback control to adjust the bus voltage, adopts the bus voltage feedforward double closed loop control strategy to stabilize the output voltage, and solves the problems of low energy utilization rate and bus voltage instability of the traditional submarine power supply system. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is the schematic diagram of the power supply system of the adapter box for the submarine observation network of the application

[0042] Figure 2 It is the topological graph of the power supply system of the adapter box for the submarine observation network of the embodiment of the application

[0043] Figure 3A DC / DC converter submodule communication strategy and a bidirectional voltage comparison flowchart of the application are shown in the figure.

[0044] Figure 4 A bus voltage feedforward double-closed-loop control block diagram of a post-stage voltage-stabilized DC / DC converter of the application is shown in the figure.

[0045] Figure 5 A double-mode control block diagram of a reverse-feedback-energy DC / DC converter of the application is shown in the figure. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the application clearer, the technical solutions of the application are further described in detail below in combination with the drawings, and the described embodiments are only a part of the embodiments involved in the application. All non-innovative embodiments of other researchers in the field on the basis of the embodiments belong to the protection scope of the application. Meanwhile, the step numbers in the embodiments are only set for the convenience of description and explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0047] In one embodiment of the application, a power supply architecture and control method of a 3kV high-voltage DC input and 48V low-voltage output are proposed for a power supply system of a cabling box of an ocean observation network. Figure 1 As shown in the figure, the system structure includes a front-stage ISOP isolated DC / DC converter, a post-stage voltage-stabilized DC / DC converter and a reverse-feedback-energy DC / DC converter.

[0048] Specifically, the input end of the front-stage ISOP isolated DC / DC converter is connected to a DC power cable system of the ocean observation network, and the output end is a DC low-voltage bus; the input end of the post-stage voltage-stabilized DC / DC converter is connected to the output end of the ISOP isolated DC / DC converter, and the output end is connected to a power supply port of an ocean observation instrument; the input end of the reverse-feedback-energy LLC converter is connected to the output end of the ISOP isolated DC / DC converter, and the output end is connected back to the DC power cable system.

[0049] The cabling box power supply system topology provided in the embodiment is shown in the figure. Figure 2As shown, the front-stage ISOP isolation type DC / DC converter adopts an ISOP-LLC converter, which is composed of five input series and output parallel LLC converter sub-modules, and the input voltage of each sub-module is 600V without considering the difference in device parameters, which can effectively reduce the voltage stress of the switching tube and improve the input voltage of the interface box power supply system. The rear-stage voltage-stabilized DC / DC converter adopts a Buck converter, and the Buck converter adopts a wide input voltage design, and the output voltage is stabilized through feedforward compensation double closed-loop control. In view of the output voltage surge characteristics of the LLC converter at light load, a reverse feedback energy DC / DC converter is additionally arranged to feed back the excess energy to the DC cable system, and the reverse feedback energy DC / DC converter adopts an LLC converter.

[0050] In actual application, due to the discreteness of device parameters and the mutual independence of driving signals of each LLC sub-module, the input voltages of each LLC sub-module are not uniform, which leads to voltage surge of a single sub-module and short circuit caused by breakdown of the power device of the sub-module.

[0051] To solve the problem of non-uniform input voltage of the LLC sub-module, the present application realizes the uniform input voltage of the LLC sub-module through a bidirectional voltage comparison algorithm combined with a voltage equalization control method.

[0052] Specifically, the present embodiment obtains the maximum input voltage V in_max of each LLC sub-module through a ring communication topology and a bidirectional voltage comparison algorithm. Figure 3 As shown, each LLC converter sub-module adopts a ring communication topology, and each sub-module only establishes a communication link with two adjacent sub-modules. In the downlink comparison stage, the first-stage sub-module transmits the input voltage of the sub-module as the downlink maximum value to the next stage, and the subsequent sub-modules compare the uplink received value V RXD with the input voltage value of the sub-module and transmit the larger value downward; in the uplink comparison stage, the last-stage sub-module transmits the input voltage of the sub-module as the uplink maximum value to the previous stage, and the previous-stage sub-modules compare the uplink received value V RXU with the input voltage value of the sub-module and transmit the larger value upward; in the maximum value determination stage, each sub-module compares the received uplink and downlink maximum values and takes the larger value as the maximum input voltage of each LLC converter sub-module.

[0053] After obtaining the maximum input voltage of each LLC sub-module, the maximum input voltage is multiplied by the corresponding proportionality coefficient k1 to obtain the normal working voltage threshold V th of the sub-module. Wherein k1 should be slightly less than 1 to ensure that each sub-module can work normally; if k1 is equal to 1, each sub-module may be in a closed state in actual circuit control.

[0054] In the present embodiment, k1 is 0.96, so that:

[0055] V th =k1·V in_max

[0056] If the input voltage of the nth submodule is greater than or equal to the normal operating voltage threshold of the submodule, i.e., V inn ≥V th (n = 1, 2, ... 5), then the nth submodule works normally; if the input voltage of the nth submodule is less than the normal operating voltage threshold of the submodule, i.e., V inn <V th (n = 1, 2, ... 5), then the duty cycle of the nth submodule is reduced by ΔD (ΔD is 5% in this embodiment). If the input voltage of the nth submodule is still lower than the threshold voltage after the duty cycle is reduced, then the submodule is turned off.

[0057] To stabilize the output voltage of the junction box power supply and meet the power supply requirements of various underwater observation instruments, the downstream regulated DC / DC converter adopts a bus voltage feedforward voltage outer loop current inner loop control strategy.

[0058] In this embodiment, as Figure 4 As shown, the reference voltage V is set. ref The voltage is 48V. The output voltage is sampled to obtain V. o Using reference voltage V ref Subtract the output voltage V o The output voltage error is obtained, and the output voltage error is used by the first PI controller to generate an inductor current reference value I. ref Use the inductor current reference value I ref Subtract the inductor current sampling value I L The inductor current error is obtained, and the inner current loop generates a d' signal from the inductor current error via the second PI controller.

[0059] To reduce the impact of DC low-voltage bus voltage fluctuations on the output voltage of the subsequent regulated DC / DC converter, this invention uses the DC low-voltage bus voltage to perform feedforward compensation on the control loop of the subsequent regulated DC / DC converter.

[0060] Specifically, a feedforward gain coefficient K is introduced. For the Buck converter in this embodiment, K is set to 1: based on the DC bus voltage sampling value V... bus The feedforward correction operation d = K·d' / V is performed on the output signal of the second PI controller. bus The final output is sent to the PWM modulator.

[0061] Since the front - end ISOP - LLC converter adopts an open - loop design, to maintain the stability of the DC low - voltage bus voltage, the switching frequency of each LLC sub - module is slightly less than the resonant frequency of the resonant cavity, and the LLC converter operates in the DC transformer (DCX) mode. However, although the selection of the LLC operating mode can maintain the stability of the DC low - voltage bus voltage to a certain extent, in the actual circuit, the output voltage of the LLC converter still soars under light - load and no - load conditions, resulting in the breakdown of the power devices in the subsequent circuit.

[0062] To solve this problem, the present invention suppresses the soaring of the DC low - voltage bus voltage by feeding back power from the reverse - feeding LLC converter to the DC power cable system.

[0063] Specifically, in this embodiment, the front - end ISOP - LLC converter is designed with a rated input of 3 kV and a rated output of 500 V. Due to the input voltage fluctuation of the DC power cable system and the load fluctuation, the output voltage V of the front - end ISOP - LLC converter in the actual circuit bus will fluctuate between 500 V and 800 V.

[0064] Since the fluctuation range of the DC low - voltage bus voltage is large, a dual - mode energy feedback control algorithm is designed. When the bus voltage rises slightly, power closed - loop control is adopted to feed back power, and when the bus voltage rises significantly, voltage - power dual - closed - loop control is adopted to suppress the soaring of the DC low - voltage bus voltage.

[0065] The dual - mode energy feedback control algorithm of the reverse - feeding LLC converter specifically includes:

[0066] Reference voltage setting: Since the rated input of the front - end ISOP - LLC converter is 3 kV and the rated output is 500 V, the desired DC low - voltage bus voltage V bus_ref is 500 V;

[0067] Threshold voltage calculation: Multiply the ideal DC bus voltage value V bus_ref by the corresponding proportionality coefficients k2 and k3 (1 < k2 < k3 < 2) to obtain the power feedback voltage threshold V bus_th and the dual - loop control voltage threshold V bus_max .

[0068] In this embodiment, with a fluctuation range of 500 V - 800 V, k2 is taken as 1.2 and k3 is taken as 1.4, then:

[0069] V bus_th = k2·V bus_ref = 600 V

[0070] V bus_max = k3·V bus_ref = 700 V

[0071] During the rise of DC low-voltage bus voltage, if V bus_th <V bus <V bus_max Then the reverse-feedback DC / DC converter enables the power closed-loop control mode. If V bus ≥V bus_max Then the reverse-feed DC / DC converter switches to voltage-power dual closed-loop control mode.

[0072] Because the power closed-loop control mode has limited ability to suppress DC bus voltage, if the reverse-feedback LLC converter switches from the voltage-power dual closed-loop control mode to the power closed-loop control mode during the DC low-voltage bus voltage drop, it may cause the DC low-voltage bus voltage to reach the dual-loop control voltage threshold V. bus_max The switching between left and right is so erratic that the two control modes of the reverse-feedback LLC converter adopt a hysteresis comparison switching scheme.

[0073] During the DC low-voltage bus voltage drop process, when the DC low-voltage bus voltage drops from above V... bus_max Decrease to (V) bus_th V bus_max When the voltage is between ) and ), maintain the dual-loop control mode; when the DC low-voltage bus voltage continues to drop to V bus_th The reverse-feed DC / DC converter will be shut down under the following conditions.

[0074] Unlike the PFM voltage and current dual-loop control mode of traditional LLC converters, the reverse-feedback LLC converter described in this embodiment adopts power closed-loop control, such as... Figure 5 As shown, Figure 5 (a) shows the flow of power closed-loop control for the reverse-feedback DC / DC converter. Figure 5 (b) shows the flow of voltage-power closed-loop control for a reverse-feed DC / DC converter.

[0075] Specifically, in this embodiment, the power closed-loop control of the reverse-feedback LLC converter includes a power sampling unit, an error adjustment unit, and a PWM modulation unit.

[0076] The power sampling unit is used to obtain the power sampling value of the reverse-feedback LLC converter. The input current I of the reverse-feedback LLC converter is... infb The input current of the LLC converter is sampled from the DC low-voltage bus voltage. Since the input current of the LLC converter is not DC, the input current of the reverse-feedback LLC converter needs to be low-pass filtered. The cutoff frequency of the low-pass filter should be much lower than the switching frequency, typically selected as 1 / 1000 to 1 / 2000 of the switching frequency.

[0077] The switching frequency of the reverse feedback energy LLC converter in this embodiment is 500 kHz, and the cutoff frequency of the low-pass filter is selected as 318.5 Hz. The transfer function of the low-pass filter is shown in the following formula:

[0078]

[0079] In the formula, τ is 100, and I infb The DC component of the input current of the LLC converter obtained through the low-pass filter is multiplied by the bus voltage sampling value V bus The power sampling value P of the reverse feedback energy LLC converter is obtained. in .

[0080] The error adjustment unit is composed of a first subtractor and a third PI controller. The input power reference value in the power closed-loop control is determined according to the rated power of the front-stage ISOP-LLC converter. Through analysis of the load characteristics of the actual circuit of the ISOP-LLC converter, it is known that the input power reference value of the reverse feedback energy LLC converter is selected to be about 1 / 6 of the rated power of the ISOP-LLC converter. In this embodiment, the power reference value is selected to be 500 W. The power reference value is connected to the positive input end of the first subtractor, and the output end of the power sampling unit is connected to the negative input end of the first subtractor. The output of the first subtractor is the input power error. The output end of the first subtractor is connected to the input end of the third PI controller.

[0081] To prevent the duty cycle of the reverse feedback energy LLC converter from exceeding 0.5, the third PI controller adopts a PI controller with anti-integral saturation, and its transfer function is as follows:

[0082]

[0083] In the formula, K p1 represents the proportional gain, K i1 represents the integral gain, and s represents the Laplace transform variable.

[0084] According to the specific parameters of the reverse feedback energy LLC converter in this embodiment, the specific parameters of the third PI controller are selected as follows: K p1 = 0.5, and K i1 = 50.

[0085] The modulation unit. In this embodiment, the reverse feedback energy LLC converter adopts a PWM modulation mode. The output end of the third PI controller is connected to the input end of the PWM modulator, and the modulation signal output by the PWM modulator is connected to the control end of the reverse feedback energy LLC converter.

[0086] To further suppress the surge of the DC low-voltage bus voltage, when V bus ≥ V bus_maxAt this time, the reverse feedback energy LLC converter adopts voltage-power double closed loop control, which is composed of voltage outer loop and power inner loop control. The voltage outer loop is composed of a second subtractor and a fourth PI controller. Since the higher the DC bus voltage is, the higher the energy required to be sent back to the DC cable system by the reverse feedback energy LLC is, therefore, the ideal DC bus voltage value V bus_ref The second subtractor negative input end is connected with a voltage reference value, and the second subtractor positive input end is connected with a DC bus voltage sampling value, so as to obtain a bus voltage error value.

[0087] The second subtractor output end is connected with the fourth PI controller input end, and the fourth PI controller output serves as a power reference value to provide a power reference for the inner loop, forming a cascade control structure. The specific parameters of the fourth PI controller are selected as follows: K p2 = 5, K i2 = 300.

[0088] In summary, the application is suitable for the power supply system of the junction box of the seabed observation network. The front-stage ISOP isolation type DC / DC converter adopts a multi-module input series output parallel structure, and the input end is connected with the seabed DC cable system. The rear-stage voltage stabilizing DC / DC converter provides stable electric energy for the observation instrument, and the reverse feedback energy DC / DC converter feeds back the excess energy to the DC cable system. At the same time, the bidirectional voltage comparison algorithm is used to realize the input voltage equalization control of the sub-modules, the bus voltage is adjusted in combination with the double-mode power feedback control, the bus voltage feedforward double closed loop control strategy is adopted to stabilize the output voltage, the problems of low energy utilization rate and bus voltage instability of the traditional seabed power supply system are solved, the wide input voltage and high fault tolerance capability are achieved, and the reliability and energy transmission efficiency of the seabed observation network power supply system can be improved.

[0089] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0090] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only illustrative of the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A junction box power system for an ocean observatory network, comprising: The topology of the adapter box power supply system comprises: a front-stage ISOP isolated DC / DC converter, a rear-stage voltage-stabilized DC / DC converter, and a reverse feedback DC / DC converter; The front-stage ISOP isolated DC / DC converter is connected to the input end of the submarine observation network DC power cable system, and the output end is connected to the DC low-voltage bus, and comprises a plurality of input series output parallel isolated DC / DC converter sub-modules; The rear-stage voltage-stabilized DC / DC converter is connected to the output end of the ISOP isolated DC / DC converter, and the output end is connected to the power supply port of the submarine observation instrument to provide stable power; The reverse feedback DC / DC converter is connected to the output end of the ISOP isolated DC / DC converter, and the output end is connected back to the submarine observation network DC power cable system; In the front-stage ISOP isolated DC / DC converter, each DC / DC converter sub-module adopts a ring communication topology, and each sub-module only establishes a communication link with two adjacent sub-modules, and the maximum input voltage of each DC / DC converter sub-module is obtained through bidirectional voltage comparison, and specifically comprises: Downward comparison stage: the primary DC / DC converter submodule transmits the input voltage as the downward maximum value to the secondary DC / DC converter submodule, and the subsequent DC / DC converter submodule compares the downward received value V RXD After comparing with the current submodule input voltage value, the larger value is transmitted downward; Upward comparison stage: the input voltage of the last-stage DC / DC converter submodule is transmitted to the front-stage DC / DC converter submodule as the maximum value, and the front-stage DC / DC converter submodule compares the received values V RXU The greater value is transmitted upward after comparing with the input voltage value of the current submodule. In the maximum value determination stage, each DC / DC converter sub-module compares the received uplink and downlink larger values, and takes the maximum value of the uplink and downlink received values as the maximum input voltage of each DC / DC converter sub-module; The control method of the adapter box power supply system comprises the following steps: S1, the voltage of each DC / DC converter sub-module in the front-stage ISOP isolated DC / DC converter is controlled, the maximum input voltage of each DC / DC converter sub-module is obtained through bidirectional voltage comparison, and the working state of each DC / DC converter sub-module is determined; S2, the output voltage of the rear-stage voltage-stabilized DC / DC converter is controlled, and a bus voltage feedforward double-closed-loop control strategy is adopted for voltage-current double-closed-loop control; the inductance current reference value is generated by the output voltage error through the voltage outer ring; the output signal is generated by the inductance current error through the current inner ring; the feedforward correction is executed through the feedforward compensation channel output signal, and the signal after the feedforward correction is output to the PWM / PFM modulator to stabilize the output voltage; S3, the reverse feedback DC / DC converter is controlled based on the DC low-voltage bus voltage, and a dual-mode control method of power closed-loop control mode and voltage-power double-closed-loop control mode is adopted, and the control mode is switched through a hysteresis comparison strategy, and the excess energy is fed back to the DC power cable to adjust the DC low-voltage bus voltage.

2. The junction box power system for an ocean observatory network of claim 1, wherein, The DC / DC converter sub-module adopts a voltage equalization control method, specifically comprising: Voltage threshold generation: multiply the maximum input voltage by the corresponding proportionality coefficient k1, 0<k1<1, to obtain the normal working voltage threshold of the DC / DC converter sub-module; Working state selection: if the input voltage of the DC / DC converter submodule is greater than or equal to the normal working voltage threshold of the submodule, the DC / DC converter submodule works normally; if the input voltage of the DC / DC converter submodule is less than the normal working voltage threshold of the submodule, the duty ratio is reduced by ΔD, and if the input voltage of the submodule is still lower than the voltage threshold after the duty ratio is reduced, the current DC / DC converter submodule is turned off.

3. The junction box power system for an ocean observatory network of claim 1, wherein, The post-stage voltage-stabilized DC / DC converter adopts a bus voltage feedforward double closed-loop control strategy, specifically including: Sampling unit: DC low-voltage bus voltage, inductor current and output voltage V of the post-stage voltage-stabilized DC / DC converter o Sampling is performed using reference voltage V ref Subtract output voltage V o Output voltage error is obtained; Voltage-current double closed loop: the voltage outer loop generates inductance current reference value I from output voltage error through first PI controller ref Subtract inductance current sampling value I ref from inductance current reference value I L Get inductance current error, the current inner loop generates d' signal output from inductance current error through second PI controller; Feedforward compensation path: through the direct current low-voltage bus voltage sampling value V bus Perform feedforward correction operation on the second PI controller output signal: d = K - d' / V bus Wherein, K is the feedforward gain coefficient; the signal d after the feedforward correction is output to the PWM / PFM modulator.

4. The junction box power system for an ocean observatory network of claim 3, wherein, The reverse feedback DC / DC converter adopts a double-mode control method, specifically including the following steps: The reference voltage setting: according to the load characteristic of the front-stage ISOP isolated DC / DC converter, the ideal direct-current low-voltage bus voltage value V is determined bus_ref ; Voltage threshold calculation: the ideal DC low-voltage bus voltage value V bus_ref is multiplied by the corresponding proportional coefficient k2, k3, 1 < k2 < k3 < 2, respectively, to obtain the power feedback voltage threshold V bus_th and the double-loop control voltage threshold V bus_max ; Control mode switching: during the process of DC low-voltage bus voltage rising, if V bus_th <V bus <V bus_max , the reverse feedback DC / DC converter enables power closed-loop control mode; if V bus ≥V bus_max , the reverse feedback DC / DC converter switches to voltage-power double closed-loop control mode.

5. The junction box power system for an ocean observatory network of claim 4, wherein, The control mode of the reverse feedback DC / DC converter is switched through a hysteresis comparison strategy, specifically including: In the process of DC low-voltage bus voltage drop, when the DC low-voltage bus voltage is between V bus_max and (V bus_th , V bus_max ), the voltage-power double closed-loop control mode is maintained; when the DC low-voltage bus voltage continues to drop to V bus_th , the reverse feedback DC / DC converter is turned off.

6. The junction box power system for an ocean observatory network of claim 4, wherein, The power closed-loop control mode loop of the reverse feedback DC / DC converter includes: Power sampling unit: composed of DC low-voltage bus voltage sampling, reverse feedback DC / DC converter input current sampling, multiplier and low-pass filter; the reverse feedback DC / DC converter input current sampling value I infb The signal is connected to the input end of the low-pass filter, and the output end of the low-pass filter is connected to the first input end of the multiplier. bus The second input end of the multiplier is connected, and the output end of the multiplier is used as the output end of the power sampling unit to obtain the power sampling value of the reverse feedback DC / DC converter. The error adjustment unit is composed of a first subtractor and a third PI controller, the power reference value input is connected to the positive input end of the first subtractor, the output end of the power sampling unit is connected to the negative input end of the first subtractor, and the output end of the first subtractor is connected to the input end of the third PI controller; The PWM / PFM modulation unit, the output end of the third PI controller is connected to the input end of the PWM / PFM modulator, and the output end of the PWM / PFM modulator is connected to the control end of the reverse feedback DC / DC converter.

7. The junction box power system for an ocean observatory network of claim 6, wherein, The voltage-power double closed-loop control mode loop of the reverse feedback DC / DC converter is superimposed on the power closed-loop control mode loop: The voltage outer loop is composed of a second subtractor and a fourth PI controller, and the ideal DC low-voltage bus voltage value V bus_ref The second subtractor is connected with a voltage reference value, the DC low-voltage bus voltage sampling value is connected with a positive input terminal of the second subtractor, and an output terminal of the second subtractor is connected with an input terminal of the fourth PI controller. The output of the fourth PI controller is used as a power reference value to provide a power reference for the inner loop, thereby forming a cascade control structure.

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