A medium voltage conversion power supply device suitable for an ocean observatory network

Abstract

The application discloses a kind of medium voltage conversion power supply devices suitable for seafloor observatory network, between main base station and adapter box, in the full load state of scientific instrument, if adapter box operating voltage is kept above 20% of minimum threshold, single front stage module operating mode is used, otherwise front and rear double stage module operating mode is used;When single front stage module operating mode is used, the device includes front stage boost module, which boosts medium voltage DC power by one stage, and directly supplies adapter box through sea cable transmission line;When front and rear double stage module operating mode is used, the device includes series-connected front stage boost module and rear stage boost and buck module;Front stage boost module boosts medium voltage DC power by one stage and transmits it to rear stage boost and buck module, rear stage boost and buck module injects communication signal to sea cable transmission line, and transmits it back to front stage boost module, which recognizes and activates secondary boost function, and rear stage boost and buck module converts boosted DC power into medium voltage DC power and supplies adapter box.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ocean bottom observation network, and particularly relates to a medium voltage conversion power supply device suitable for an ocean bottom observation network. BACKGROUND

[0002] The main network of the ocean bottom observation network is composed of a shore-based power supply, a submarine cable and a main base station. The shore-based power supply converts commercial power into high-voltage direct current and transmits the high-voltage direct current to the main base station through the submarine cable. The main base station converts the high-voltage direct current into 375V medium voltage direct current and outputs the 375V medium voltage direct current to a connection box.

[0003] In the actual deployment process, the distance from the connection box to the main base station varies from tens of meters to tens of kilometers according to the observation needs.

[0004] For the connection box tens of kilometers away, if the 375V medium voltage transmission is still used, because the submarine cable has a relatively large resistivity (about 1Ω / kM), a large current can cause a voltage drop of tens to hundreds of volts on the transmission line. When the electric energy reaches the connection box, the voltage near the connection box is close to the lower limit of the supply voltage, which is easy to trigger the low-voltage protection and affect the observation. SUMMARY

[0005] In view of the demand of the ocean bottom observation network for medium voltage long-distance high-power electric energy transmission, the purpose of the present application is to overcome the defects of the prior art and provide a medium voltage conversion power supply system with flexible configuration and self-adaptive adjustment.

[0006] The present application provides a medium voltage conversion power supply device suitable for an ocean bottom observation network, which is deployed between the main base station and the connection box. In the full load state of the scientific instrument, if the working voltage of the connection box is kept above 20% of the minimum threshold, a single front-end module working mode is used, otherwise a front-rear dual module working mode is used.

[0007] When the single front-end module working mode is used, the device comprises a front-end boost module, which boosts the medium voltage direct current provided by the main base station by one level and directly supplies the connection box through the submarine cable transmission line.

[0008] When the front-rear dual module working mode is used, the device comprises a front-end boost module and a rear-end boost-buck module connected in series. The front-end boost module boosts the medium voltage direct current provided by the main base station by one level and transmits the medium voltage direct current to the rear-end boost-buck module. The rear-end boost-buck module injects a communication signal into the submarine cable transmission line, transmits the communication signal back to the front-end boost module, and the front-end boost module identifies and activates the secondary boost function. The output voltage is further improved, and the rear-end boost-buck module converts the boosted direct current into medium voltage direct current to supply the connection box.

[0009] Preferably, the submarine cable transmission line is a single-polarity or double-polarity submarine cable.

[0010] Preferably, in the single front-stage module working mode, the voltage range of the first-stage voltage boost is not more than the upper limit of the power supply voltage of the adapter box.

[0011] Preferably, the front-stage voltage boost module comprises a plurality of mutually independent sub-voltage boost modules connected in parallel, and the sub-voltage boost module comprises an isolation voltage boost circuit, an auxiliary power supply circuit, a sampling circuit, a master control circuit and a detection circuit.

[0012] The isolation voltage boost circuit is configured to boost the medium-voltage direct current provided by the main base station to a target voltage and achieve single-pole and double-pole submarine cable compatibility through an isolation transformer.

[0013] The auxiliary power supply circuit is configured to provide power for other circuits.

[0014] The sampling circuit is configured to collect the real-time state of the input and output current, voltage and system temperature.

[0015] The master control circuit is configured to control the sub-voltage boost module.

[0016] The detection circuit is configured to communicate with the rear-stage voltage boost and buck module to determine the working mode.

[0017] Preferably, the start-up process of the front-stage voltage boost module comprises:

[0018] The voltage of the input medium-voltage direct current is determined to be in a normal state, and the single front-stage module working mode is adopted, the front-stage voltage boost module performs first-stage voltage boost, and enters a detection waiting state; otherwise, it is determined to be a fault, and the determination is continued.

[0019] The communication signal is waited for, and if the communication signal is received, the rear-stage voltage boost and buck module exists, the front-rear dual-stage module working mode is adopted, and the front-stage voltage boost module activates the second-stage voltage boost function.

[0020] Preferably, in the single front-stage module working mode, the voltage V o output by the first-stage voltage boost is:

[0021] V o = V basic1 + I o *C1

[0022] wherein V o is a target operating voltage, V basic1 is a medium-voltage direct current base voltage, I o is an output current, and C1 is a voltage boost coefficient determined by the submarine cable structure and length; when the line is in an idle state, the front-stage voltage boost module maintains V basic1 output, and when the output power in the line rises, the front-stage voltage boost module output voltage rises to offset the influence of the transmission line voltage drop on the adapter box.

[0023] In a multi-sub-boost module system, a single sub-boost module handles all the power, while the other sub-boost modules maintain V. basic1 The system is running, and the front-end boost module is in a semi-hot backup state.

[0024] Preferably, in the dual-stage module operating mode, the voltage V output by the second-stage boost converter is... o for:

[0025] V o =V basic2 -I o *C2

[0026] Among them, V o The operating voltage for the target operation, V basic2 For the secondary boost base voltage, I o C1 is the output current, and C2 is the current sharing coefficient.

[0027] Multiple sub-boost modules share current through a drop-out method, and the front-end boost module is in a hot backup state.

[0028] Preferably, the subsequent buck-boost module includes multiple independent sub-buck-boost modules connected in parallel. Each sub-buck-boost module includes: an isolation buck-boost circuit, an auxiliary power supply circuit, a sampling circuit, a main control circuit, and a signal superposition circuit; wherein,

[0029] The isolation step-up / step-down circuit is used to convert the DC power of the transmission line to medium-voltage DC power, and to achieve compatibility between single and double-pole submarine cables through the isolation transformer;

[0030] The sampling circuit is used to collect the input and output current, voltage, and real-time system temperature status.

[0031] The main control circuit is used to control the sub-boost-buck module;

[0032] The signal superposition circuit is used to inject communication signals into the submarine cable transmission line to complete communication with the front-end boost module.

[0033] The multiple independent sub-boost modules connected in parallel are hot-backed using the Droop current sharing algorithm.

[0034] Preferably, the startup process of the downstream buck-boost module includes:

[0035] Inject communication signals into the submarine cable transmission line and wait;

[0036] After the timeout period, it is determined whether the input voltage has reached the set threshold. If it is, the subsequent buck-boost module operates at full load and outputs medium-voltage DC power; otherwise, power is limited while maintaining constant voltage output, and the output power is limited to half load.

[0037] Compared with the prior art, the advantages of the present invention are:

[0038] 1. The present invention proposes an adaptive power transmission system that can achieve cable length self-matching and output voltage self-adaptation under medium-voltage long-distance high-power transmission conditions, always keeping the power supply voltage on the junction box side within a reasonable range, reducing the risk of input undervoltage and improving observation stability.

[0039] 2. The front-end and back-end modules proposed in this invention can be configured in different ways according to the actual distance and power requirements, so as to achieve a balance between long-distance high-power transmission and system complexity.

[0040] 3. The adaptive operation mode algorithm proposed in this invention can automatically select the operation mode according to different module configurations, thereby reducing line loss.

[0041] 4. The inter-module carrier communication scheme proposed in this invention can reduce additional communication lines and simplify system design. Attached Figure Description

[0042] Figure 1 This is a system composition diagram of a medium-voltage power conversion device;

[0043] Figure 2 This is an internal block diagram of the front-end boost module;

[0044] Figure 3 This is the startup flowchart of the pre-amplifier boost module;

[0045] Figure 4 This is a schematic diagram of a submarine cable transmission line;

[0046] Figure 5 This is an internal block diagram of the post-stage buck-boost module;

[0047] Figure 6 This is the startup flowchart for the post-stage boost / buck module. Detailed Implementation

[0048] This invention provides a medium-voltage power conversion device suitable for submarine observation networks, designed to solve the problem of long-distance, high-power underwater medium-voltage power transmission. Its components are as follows: Figure 1 As shown, it consists of a pre-amplifier module (referred to as the pre-amplifier module), a submarine cable transmission line, and a post-amplifier module (referred to as the post-amplifier module).

[0049] The front-end module is located in the main power supply network of the observation network. Its input is medium-voltage DC power provided by the main base station, and its output is connected to the submarine cable transmission line.

[0050] The downstream module is located on the input side of the junction box. Its input is connected to the submarine cable transmission line, and its output is medium-voltage DC power, which is connected to the junction box input. The downstream module can be omitted as needed to further simplify the system; in this case, the submarine cable transmission line is directly connected to the junction box.

[0051] This invention offers two operating modes: a single front-end module and a dual-module (front and rear) configuration. In actual deployment, the selection is based on the estimated load power, node distance, cable type, power margin, allowable cable loss, junction box voltage threshold, and scientific instrument voltage range. Typically, under full load conditions for the scientific instrument, if the junction box operating voltage remains above 20% of the minimum threshold, the single front-end module solution is suitable; otherwise, the dual-module (front and rear) solution is used.

[0052] The single front-end module operates as follows: the medium-voltage DC power supplied by the main base station is boosted by the front-end module, and the boost range does not exceed the upper limit of the power supply voltage of the junction box. The power is then directly supplied to the junction box via the submarine cable.

[0053] The dual-module operation mode is as follows: the medium-voltage DC power provided by the main base station is boosted by the front-end module, which has a higher voltage level than the single front-end module. After being transmitted through the submarine cable, the boosted DC power is converted into 375V medium-voltage DC power by the back-end module to supply the junction box.

[0054] This invention can adaptively adjust for single front-end module or dual front-end and rear-end module working modes.

[0055] When operating with a single preamplifier, the preamplifier boost module slowly starts up and outputs medium-voltage DC power. The power is transmitted to the junction box via the submarine cable. Since there is no downstream module in the transmission system, the secondary boost function of the preamplifier module cannot be activated, and the module operates stably in primary boost mode. Its output voltage automatically increases according to the output current to prevent the junction box from entering the undervoltage lockout range.

[0056] When the front-end and rear-end modules are operating, the front-end boost module slowly starts up and outputs medium-voltage DC power. Power is transmitted to the rear-end module via the submarine cable. At this time, the power in the transmission line is almost zero, and the cable voltage drop is negligible. After the rear-end module starts up, it injects a communication signal into the submarine cable. The signal is transmitted back to the front-end module via the submarine cable. Upon recognition, the front-end module activates the second-stage boost function, further increasing the output voltage. The rear-end module reads the submarine cable voltage within a certain time limit. When the voltage reaches a set threshold, it outputs constant medium-voltage DC power in full-power mode. When the voltage does not reach the set threshold, it outputs constant medium-voltage DC power in half-power mode to supply the junction box.

[0057] Key innovations:

[0058] 1. By boosting the transmission line voltage through a boost module, the purpose of medium-voltage long-distance high-power power transmission can be achieved.

[0059] 2. The front and rear stage modules can be used together. When the rear stage module is present, the output voltage is further increased, and the transmission line loss is reduced.

[0060] 3. The front-end and back-end modules can communicate and handshake, and adaptively adjust the working mode. The modules can be configured reasonably according to the actual project needs.

[0061] 4. The front-end and back-end modules communicate via carrier waves through transmission lines, reducing additional communication lines and lowering system complexity.

[0062] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0063] Example

[0064] An embodiment of the present invention provides a medium-voltage power conversion device suitable for submarine observation networks, which consists of a front-end module, a submarine cable transmission line, and a back-end module.

[0065] The front-end module is located at the main base station. Its input is the medium-voltage DC power provided by the main base station, and its output is connected to the submarine cable transmission line.

[0066] Submarine transmission lines can be unipolar or bipolar, depending on the actual construction requirements.

[0067] The downstream module is located on the input side of the junction box. Its input is connected to the submarine cable transmission line, and its output is medium-voltage DC power, which is connected to the junction box input. The downstream module can be omitted as needed to further simplify the system; in this case, the submarine cable transmission line is directly connected to the junction box.

[0068] This invention offers two operating modes: a single front-end module and a dual-module (front and rear) configuration. In actual deployment, the selection is based on the estimated load power, node distance, cable type, power margin, allowable cable loss, junction box voltage threshold, and scientific instrument voltage range. Typically, under full load conditions for the scientific instrument, if the junction box operating voltage remains above 20% of the minimum threshold, the single front-end module solution is suitable; otherwise, the dual-module (front and rear) solution is used.

[0069] The single front-end module operates as follows: the medium-voltage DC power provided by the main base station is boosted by the front-end module, and the boost voltage does not exceed the voltage limit of the junction box. The power is then directly supplied to the junction box via the submarine cable.

[0070] The dual-module operation mode is as follows: the medium-voltage DC power provided by the main base station is boosted by the front-end module in two stages, and the boosted voltage level is higher than that of the first stage boost. After being transmitted through the submarine cable, the boosted DC power is converted into medium-voltage DC power by the back-end module to supply the junction box.

[0071] The internal structure of the front-end module is as follows Figure 2As shown, the system consists of multiple independent sub-boost modules connected in parallel for redundancy. Internally, it comprises an isolation boost circuit, an auxiliary power supply circuit, a sampling circuit, a main control circuit, and a detection circuit. The isolation boost circuit is responsible for boosting the medium-voltage DC power to the target voltage and achieving compatibility with single- and bipolar submarine cables through an isolation transformer. The auxiliary power supply circuit provides power to other circuits within the module. The sampling circuit collects real-time data such as input and output current and voltage, and system temperature. The main control circuit controls the system, and the detection circuit communicates with downstream modules to determine the operating mode of the boost module.

[0072] Its startup process is as follows Figure 3 As shown.

[0073] 1. After the system is powered on and started, it is determined whether the input voltage is sufficient. If it is in a normal state, the front-end module operates in a first-stage boost mode and enters the detection waiting state.

[0074] 2. If a downstream module exists, it will receive a communication signal. After completing the signal reception, the module enters the second-stage boost mode.

[0075] 3. If no communication signal is received, the module continues to operate in the first-level boost mode.

[0076] The adaptive operating voltage algorithm ensures that the scientific load remains in a stable operating state when operating at different platform voltages.

[0077] 1. The output voltage algorithm for the first-stage boost mode is: V o =V basic1 +I o *C1, where V o The operating voltage for the target operation, V basic1 For medium-voltage DC base voltage, I o C1 is the output current, and C1 is the boost factor, determined by the submarine cable structure and length. When the line is under no-load, the front-end module maintains V. basic1 In this mode, as the output power in the line increases, the output voltage of the front-end module also increases to offset the effect of the transmission line voltage drop on the junction box. In this mode, a single sub-boost module handles all the power, while the other modules maintain a constant voltage. basic1 The system is running and in a semi-hot backup state.

[0078] 2. The output voltage in the two-stage boost mode is: V o =V basic2 -I o *C2, where V o The operating voltage for the target operation, V basic2 For the secondary boost base voltage, I oC1 represents the output current, and C2 represents the current sharing coefficient. The boost module raises the output voltage to the second-stage boost platform, and then the subsequent buck module lowers it to a medium voltage. Transmission line losses are completely isolated from the scientific load. In this mode, multiple sub-boost modules share the output current via a drop-out method, and the system is in a hot backup state.

[0079] Submarine cable transmission methods such as Figure 4 There are two types: unipolar and bipolar. Unipolar transmission forms a conductive loop with the seawater through a grounding electrode, resulting in lower line impedance and smaller voltage drop. Unipolar submarine cables have higher technological maturity, but require an additional grounding electrode. Bipolar submarine cables do not require an additional grounding device, but have higher line impedance and greater voltage drop, and their technological maturity is lower than that of unipolar submarine cables. The specific construction method can be selected according to the actual project requirements.

[0080] The internal structure of the subsequent module is as follows Figure 5 As shown, the system consists of multiple independent sub-boost-buck modules connected in parallel for redundancy. Internally, it comprises an isolation boost-buck circuit, an auxiliary power supply circuit, a sampling circuit, a main control circuit, and a signal superposition circuit. The isolation boost-buck circuit converts the DC power from the transmission line to medium-voltage DC power and achieves compatibility with both single- and bipolar submarine cables through an isolation transformer. The sampling circuit collects real-time data such as input and output current, voltage, and system temperature. The main control circuit controls the system, and the signal superposition circuit injects communication signals into the submarine cable transmission line to complete communication with the boost modules. The multiple sub-boost-buck modules utilize the Droop current sharing algorithm for hot backup.

[0081] Its workflow is as follows Figure 6 As shown:

[0082] 1. After the system is powered on and started, the downstream module injects communication signals into the submarine cable transmission line and waits.

[0083] 2. After the timeout period, the input voltage is checked. If the voltage reaches the set threshold, the module enters full-load operation and outputs medium-voltage DC power. If the voltage does not reach the set threshold, power limiting is applied while maintaining constant voltage output, with the output power limited to half load.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A medium-voltage power conversion device suitable for submarine observation networks, deployed between the main base station and the junction box, characterized in that, When the scientific instrument is fully loaded, if the working voltage of the connector box remains above 20% of the minimum threshold, the single front-end module working mode is adopted; otherwise, the front and rear dual-stage module working mode is adopted. When using a single front-end module working mode, the device includes a front-end boost module, which boosts the medium-voltage DC power provided by the main base station in one stage and supplies it directly to the junction box through a submarine cable transmission line. When using a dual-stage module operating mode, the device includes a front-stage boost module and a rear-stage buck-boost module connected in series. The front-stage boost module boosts the medium-voltage DC power provided by the main base station and transmits it to the rear-stage buck-boost module. The rear-stage buck-boost module injects communication signals into the submarine cable transmission line and transmits them back to the front-stage boost module. After the front-stage boost module recognizes the signal, it activates the second-stage boost function, further increasing the output voltage. The rear-stage buck-boost module then steps down the boosted DC power and converts it into medium-voltage DC power for use by the junction box.

2. The medium-voltage power conversion device for submarine observation networks according to claim 1, characterized in that, The submarine cable transmission line is a unipolar or bipolar submarine cable.

3. The medium-voltage power conversion device for submarine observation networks according to claim 1, characterized in that, In the single front-end module operating mode, the boost voltage range of the first-stage boost does not exceed the upper limit of the power supply voltage of the junction box.

4. The medium-voltage power conversion device suitable for submarine observation networks according to claim 1, characterized in that, The pre-amplifier module includes: multiple independent sub-amplifier modules connected in parallel, each sub-amplifier module including: an isolation boost circuit, an auxiliary power supply circuit, a sampling circuit, a main control circuit, and a detection circuit; wherein, The isolation boost circuit is used to boost the medium-voltage DC power provided by the main base station to the target voltage, and to achieve compatibility between single and double-pole submarine cables through the isolation transformer; The auxiliary power supply circuit is used to provide power to other circuits; The sampling circuit is used to collect the input and output current, voltage, and real-time system temperature status. The main control circuit is used to control the sub-boost module; The detection circuit is used to communicate with the subsequent buck-boost module to determine the operating mode.

5. The medium-voltage power conversion device for submarine observation networks according to claim 4, characterized in that, The startup process of the pre-amplifier module includes: Determine if the input medium-voltage DC voltage meets the normal condition. If yes, adopt the single preamplifier module working mode, the preamplifier boost module performs a first-stage boost and enters the detection waiting state; otherwise, it is a fault, and continue to determine. Waiting for a communication signal. If received, there is a subsequent boost / buck module, which is in a two-stage module working mode. The first-stage boost module activates the second-stage boost function.

6. The medium-voltage power conversion device for submarine observation networks according to claim 5, characterized in that, In the single front-end module operating mode, the voltage V output from the first-stage boost converter is... o for: V o =V basic1 +I o *C1 Among them, V o The operating voltage for the target operation, V basic1 For medium-voltage DC base voltage, I o C1 is the output current, and C1 is the boost factor, which is determined by the structure and length of the submarine cable. When the line is under no-load, the front-end boost module maintains V. basic1 As the output power in the line increases, the output voltage of the front-end boost module also increases to offset the effect of the transmission line voltage drop on the junction box. In a multi-sub-boost module system, a single sub-boost module handles all the power, while the other sub-boost modules maintain V. basic1 The system is running, and the front-end boost module is in a semi-hot backup state.

7. The medium-voltage power conversion device for submarine observation networks according to claim 5, characterized in that, In the dual-stage module operating mode, the voltage V output from the second-stage boost converter... o for: V o =V basic2 -I o *C2 Among them, V o The operating voltage for the target operation, V basic2 For the secondary boost base voltage, I o C1 is the output current, and C2 is the current sharing coefficient. Multiple sub-boost modules share current through the Droop current sharing algorithm, and the front-end boost module is in hot backup mode.

8. The medium-voltage power conversion device for submarine observation networks according to claim 1, characterized in that, The subsequent buck-boost module includes multiple independent sub-buck-boost modules connected in parallel. Each sub-buck-boost module includes: an isolation buck-boost circuit, an auxiliary power supply circuit, a sampling circuit, a main control circuit, and a signal superposition circuit; wherein... The isolation step-up / step-down circuit is used to convert the DC power of the transmission line to medium-voltage DC power, and to achieve compatibility between single and double-pole submarine cables through the isolation transformer; The sampling circuit is used to collect the input and output current, voltage, and real-time system temperature status. The main control circuit is used to control the sub-boost-buck module; The signal superposition circuit is used to inject communication signals into the submarine cable transmission line to complete communication with the front-end boost module. The multiple independent sub-boost modules connected in parallel are hot-backed using the Droop current sharing algorithm.

9. The medium-voltage power conversion device for submarine observation networks according to claim 1, characterized in that, The startup process of the downstream buck-boost module includes: Inject communication signals into the submarine cable transmission line and wait; After the timeout period, it is determined whether the input voltage has reached the set threshold. If it is, the subsequent buck-boost module operates at full load and outputs medium-voltage DC power; otherwise, power is limited while maintaining constant voltage output, and the output power is limited to half load.

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