A low-voltage high-power DC intelligent power distribution module for ships and its control strategy

Abstract

The present invention discloses a marine low-voltage high-power DC intelligent power distribution module and its control strategy, which is characterized in that it includes a power circuit, a buffer circuit, a detection circuit, a control circuit, a drive circuit and an auxiliary power supply; it is used to distribute the power supply of the centralized power supply system to the powered load, and at the same time, it can monitor the working states of the power supply, the powered load and itself in real time, realize protection and alarm under fault conditions, and conduct information interaction with the superior monitoring system through the CAN bus to realize remote on / off control, online parameter setting and remote reset after fault removal under normal conditions. In addition, it has the ability of fast current limiting under large current impact loads and fast breaking ability under short circuit faults. Compared with traditional power distribution devices, it has the characteristics of intelligent load management, fast fault response and minimized fault impact. Its output current rating can be set online and is applicable to all power distribution occasions with a rated current below 100A in a marine 24V / 27V low-voltage DC power distribution system.

Description

Technical Field

[0001] The invention relates to a ship-based low-voltage high-power direct current intelligent power distribution module and a control strategy thereof, belonging to a ship-based low-voltage direct current intelligent power distribution system. Background Art

[0002] With the continuous improvement of the automation level of ship systems, the requirements for power supply and distribution quality, reliability and fault tolerance are becoming higher and higher. Therefore, reasonable and effective power distribution design and protection must be adopted. On the one hand, rapid current limiting is required when the impact load starts to avoid a sharp drop in the bus voltage of the centralized power supply system or false tripping of the distribution branch; on the other hand, the faulty branch should be cut off in time when a fault occurs to ensure that the fault does not spread or spread, thereby ensuring the power supply continuity of the non-faulty system.

[0003] At present, the distribution devices widely used in my country's shipbuilding field are still fuses, circuit breakers, electromechanical thermal protection relays, contactors, etc. The distribution system based on these traditional distribution devices has a slow fault response speed and does not have a current limiting function. When a large current shock occurs to the common source load or a short circuit occurs in the distribution branch, the bus voltage will drop sharply, causing sensitive loads to lose power; in addition, traditional distribution devices do not have external communication functions, which makes it impossible for the monitoring system to obtain the operating status and fault information of the distribution branch, thereby increasing the difficulty of fault isolation and positioning, and after the fault is cleared, it needs to be manually closed or replaced, which greatly increases the management and maintenance workload, and can no longer meet the requirements of ship distribution systems for informatization, digitization and intelligence.

[0004] Ship load characteristics are complex, with diverse load sizes, locations and cable routings. To avoid false protection or bus voltage drops, accurate state identification and rapid fault response must be achieved, and the action time must be strictly controlled within microseconds. For large current impact loads, in order to ensure their safe and reliable startup, it is necessary not only to quickly enter the current limiting mode, but also to continue running in the current limiting mode for a certain period of time. The instantaneous withstand power can be as high as hundreds of kW, which poses a severe challenge to the development of DC intelligent distribution modules with excellent performance and stable operation. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies of the existing technical solutions in the background technology and the technical challenges faced by the ship terminal power distribution system, a low-voltage and high-power DC intelligent power distribution module is provided.

[0006] In order to solve the above problems, the technical solution of the present invention is to provide a low-voltage high-power DC intelligent power distribution module for ships, which is characterized by comprising a power circuit, a buffer circuit, a detection circuit, a control circuit, a drive circuit and an auxiliary power supply;

[0007] The power circuit includes power devices for distributing the power supply of the centralized power supply system to the powered load;

[0008] The buffer circuit includes a capacitor C1 and a TVS diode to reduce the voltage spikes caused by line stray inductance and the surge voltage in the system, protecting the power devices and the load from voltage shocks;

[0009] The detection circuit includes a detection resistor, a thermistor, and a signal conditioning circuit to collect and condition the input and output voltages, load current, and operating temperature, and feedback them to the control circuit;

[0010] The control circuit includes a working state evaluation unit, a on / off control unit, a fault diagnosis unit, a current limiting unit, and a communication unit. According to the parameters provided by the detection circuit, it judges the working states of the power supply, the distribution branch, and itself, issues control instructions to the drive circuit, and uploads the operating state and working parameters to the monitoring system in real time;

[0011] The drive circuit is used to receive the control signal provided by the control circuit, achieve power amplification, and drive the power devices to act;

[0012] The auxiliary power supply is used to provide auxiliary power supply for each functional circuit of the DC intelligent power distribution module.

[0013] Preferably, the power circuit includes power devices, a power resistor R1, a DC power input terminal, and a DC power output terminal;

[0014] The power devices are formed by paralleling high-power, low on-state impedance MOSFETs. The drain of the MOSFET is connected to the DC power input terminal, the source is connected to the DC power output terminal through a detection resistor Rs, and the gate is connected to the output terminal of the drive circuit;

[0015] The power resistor R1 is connected between the DC power output terminal and the power ground to eliminate the floating voltage at the output terminal when the DC intelligent power distribution module is turned off.

[0016] Preferably, the buffer circuit includes a decoupling capacitor C1, a high-power TVS diode Z1, and a high-power TVS diode Z2;

[0017] The decoupling capacitor C1 is an aluminum electrolytic capacitor and is connected between the DC power input terminal and the power ground;

[0018] The TVS diode Z1 is paralleled across the drain and source of the power MOSFET;

[0019] The TVS diode Z2 is connected between the DC power output terminal and the power ground.

[0020] Preferably, the detection circuit includes a detection resistor Rs, a thermistor, and a signal conditioning circuit; the detection resistor Rs is a high-power and high-precision surface mount shunt, one end of which is connected to the source of the power MOSFET, and the other end is connected to the output terminal of the DC power supply;

[0021] The signal conditioning circuit consists of a high-speed operational amplifier.

[0022] Preferably, the control circuit adopts a digital and analog hybrid control, including a working state evaluation unit, a switching control unit, a fault diagnosis unit, a current limiting unit, and a communication unit, which are used to realize slow turn-on and slow turn-off under normal working conditions, intelligent distinction between large current impact loads and short-circuit conditions, current limiting and protection, and I 2 t inverse time limit protection function, and at the same time, the working state, operating parameters, and fault information are uploaded in real time.

[0023] Preferably, the digital control part of the control circuit adopts a minimum system based on DSP to realize switching control, communication, input over-voltage and under-voltage, over-temperature, and I 2 t inverse time limit sectional protection;

[0024] The analog control part adopts high-speed operational amplifiers and logic devices to realize hardware current limiting control and fast breaking control during short-circuit faults.

[0025] Preferably, the hardware current limiting control adopts a proportional regulation circuit. The high-speed operational amplifier U1 and resistors R1, R2, R3, and R4 form a conditioning circuit to amplify the current feedback signal. The high-speed operational amplifier U2 and resistors R5, R6, R7, and R8 form a proportional regulation circuit. V ref After voltage division, it is connected to the non-inverting input terminal of the high-speed operational amplifier U2 as the reference voltage for the holding current. The output of the high-speed operational amplifier U2 is the current limiting control voltage. The output terminal of the high-speed operational amplifier U2 is connected to the gating diode D1 through the solid-state switch Q1.

[0026] Preferably, when the current limiting control signal is valid, the solid-state switch Q1 conducts, and the current limiting control voltage is output to the control voltage connection terminal of the power MOSFET through the gating diode D1. At this time, the control voltage V c is connected to the gate of the power MOSFET through the drive circuit, controlling the power MOSFET to enter the linear region and limiting the load current to the set value.

[0027] Preferably, the auxiliary power supply includes an EMI filter and an isolated DC / DC power module, which converts the external 24V DC voltage into ±15V and +5V voltages to provide auxiliary power supply for each functional circuit of the DC intelligent power distribution module.

[0028] Preferably, the control circuit uploads the working state, operating parameters, and fault information in real time through the CAN communication network.

[0029] Another technical solution of the present invention provides a control strategy for a marine low-voltage high-power DC intelligent power distribution module, which is applied to a marine low-voltage high-power DC intelligent power distribution module as described above, and is characterized in that:

[0030] When the load current is less than 1.1 times the rated current, the DC intelligent power distribution module operates stably for a long time;

[0031] When the load current is 1.1 times the rated current, the DC intelligent power distribution module operates stably for 1 h and then is protected, the power distribution branch is cut off and the fault information is uploaded;

[0032] When the load current is greater than 1.1 times the rated current and less than 1.25 times the rated current, it enters the first-stage I 2 t inverse time protection curve; the greater the load current, the shorter the inverse time delay time;

[0033] When the load current is 1.25 times the rated current, the DC intelligent power distribution module operates stably for 3 min and then is protected, the power distribution branch is cut off and the fault information is uploaded;

[0034] When the load current is greater than 1.25 times the rated current and less than the hardware current limit value I limit When, it enters the second-stage I 2 t inverse time protection curve, the greater the load current, the shorter the inverse time delay time;

[0035] When the load current is greater than the hardware current limit threshold I th (3.5 times the rated current), the hardware control circuit makes a judgment in the microsecond level, controls the module to enter the current limiting mode, operates at a constant current, limits the load current to the set current limit value I limit , and at the same time starts the short-circuit fault judgment, compares the real-time detection value of the output voltage with the preset voltage curve. If the output voltage cannot follow the preset voltage curve and is close to 0, it is determined that there is a short-circuit fault in the power distribution branch, and the power distribution branch is quickly cut off and the fault information is uploaded; if the output voltage gradually increases but still cannot follow the preset voltage curve after the current limiting time exceeds the set threshold T th After that, it is determined that the load at the rear stage exceeds the load-carrying capacity of the capacitive and resistive impact load of the module, the power distribution branch is cut off and the fault information is uploaded; if the output voltage follows the preset voltage curve and the load current gradually decreases within the set time, the current limiting mode is exited and the normal working state is entered. If the hardware current limiting fails, software protection is executed. When it is detected that the load current is greater than or equal to the current limit value I limit , the power distribution branch is cut off after a delay of 10 ms and the fault information is uploaded;

[0036] When the load current is greater than or equal to 4 times the rated current, immediate tripping protection is executed, the power distribution branch is cut off and the fault information is uploaded.

[0037] Preferably, the hardware current limiting control strategy includes:

[0038] The hysteresis comparison strategy is adopted for entering / exit current limiting control. When the load current is greater than 3.5 times the rated current, a judgment is made within microseconds, and the current limiting control signal takes effect, and the module enters the current limiting mode; when the load current is less than 1.5 times the rated current, the current limiting control signal fails, and the module exits the current limiting mode.

[0039] In the current limiting mode, by utilizing the output characteristics of the power MOSFET itself and controlling the driving voltage, the load current is limited to a set value.

[0040] Preferably, the strategy for distinguishing between large current impact loads and short - circuit conditions includes:

[0041] An RC network is used to simulate the charging curve of a resistive - capacitive impact load, and the output voltage of the DC intelligent power distribution module is detected in real - time.

[0042] In the current limiting mode, a current limiting duration is set. By comparing the detected value of the output voltage with the simulated charging curve, if the output voltage still cannot follow the simulated charging curve when the current limiting time exceeds the set threshold, it is determined that the subsequent load exceeds the load - carrying capacity of the resistive - capacitive impact load of the module or a short - circuit fault occurs in the power distribution branch; if the output voltage follows the simulated charging curve and the load current gradually decreases within the set time, the current limiting mode is exited and the normal working state is entered.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] (1) The state recognition is accurate, the fault response is rapid, the intelligent distinction between large current impact and short - circuit conditions can be realized, and a judgment can be made within microseconds, thus avoiding the voltage drop of the bus of the centralized power supply system.

[0045] (2) It has the load - carrying capacity for large current impact loads and the instantaneous high - power tolerance ability.

[0046] (3) It can upload operation parameters and fault information through the CAN communication network and receive control instructions issued by the monitoring system, laying a foundation for the intelligent management of the load.

[0047] (4) It has the function of online parameter programming, is applicable to 24V / 27V (±20%) low - voltage DC power distribution systems, its rated current can be continuously adjusted downward, and the I 2 t inverse - time protection curve can be corrected online, applicable to all power distribution occasions below 100A (including 100A), greatly broadening the application range of the module and improving the load compatibility.

[0048] (5) It has excellent performance such as self - checking, fault isolation, information transmission, remote control and reset.

[0049] The DC intelligent power distribution module is applied to the ship field, which can greatly improve the power supply guarantee capabilities of power, power and other systems, and has a very broad application prospect. Brief Description of the Drawings

[0050] Figure 1 It is the principle block diagram of the DC intelligent power distribution module in the present invention;

[0051] Figure 2 For I 2 t inverse time - definite - current protection curve;

[0052] Figure 3 It is the schematic diagram of entering / exit current - limiting control strategy;

[0053] Figure 4 It is the schematic diagram of the current - limiting control circuit;

[0054] Figure 5 It is the test waveform of suddenly applying a resistive - capacitive impact load;

[0055] Figure 6 It is the test waveform when the distribution branch is short - circuited. Detailed Embodiment

[0056] To make the present invention more obvious and easy to understand, the preferred embodiments are hereby described in detail in conjunction with the accompanying drawings as follows.

[0057] Figure 1 As shown, it is the principle block diagram of the DC intelligent power distribution module proposed by the present invention, including a power circuit, a buffer circuit, a detection circuit, a control circuit, a drive circuit and an auxiliary power supply.

[0058] The power circuit includes: power devices, power resistor R1, DC power input terminal, DC power output terminal; the power devices are composed of 3 high - power, low - on - state - impedance MOSFETs in parallel (the number of MOSFETs in parallel can be determined according to actual requirements), the drain of the MOSFET is connected to the DC power input terminal, the source is connected to the DC power output terminal through a detection resistor, and the gate is connected to the output terminal of the drive circuit; the power resistor R1 is connected between the DC power output terminal and the power ground, and is used to eliminate the floating voltage at the output terminal when the DC intelligent power distribution module is turned off.

[0059] The buffer circuit includes: decoupling capacitor C1, high - power TVS diode Z1, high - power TVS diode Z2; the decoupling capacitor C1 uses an aluminum electrolytic capacitor, the positive electrode is connected to the DC power input terminal, and the negative electrode is connected to the power ground; the anode of the high - power TVS diode Z1 is connected to the source of the power MOSFET group, and the cathode is connected to the drain of the power MOSFET group; the anode of the high - power TVS diode Z2 is connected to the power ground, and the cathode is connected to the DC power output terminal. Here, high - power TVS diodes are preferably used as transient voltage suppressors, which have the characteristics of simple circuit implementation, stable and reliable operation.

[0060] The detection circuit includes: a detection resistor, a thermistor, and a signal conditioning circuit; the detection resistor uses a high-power and high-precision surface mount shunt resistor for collecting current signals, one end of which is connected to the source of the power MOSFET group, and the other end is connected to the DC power supply output; the signal conditioning circuit consists of high-speed operational amplifiers.

[0061] The control circuit adopts digital and analog hybrid control. The digital control part uses a minimum system based on DSP to achieve on-off control, communication, and input over-voltage, under-voltage, over-temperature, and I 2 t inverse time limit sectional protection; the analog control part uses high-speed operational amplifiers and logic devices to achieve hardware current limiting and fast breaking control during short-circuit faults.

[0062] The drive circuit receives the control signal provided by the control circuit to achieve power amplification and drive the power device to act.

[0063] The auxiliary power supply consists of an EMI filter and an isolated DC / DC power supply module, which converts the external 24V DC voltage into ±15V and +5V voltages to provide auxiliary power supply for each functional circuit of the DC intelligent power distribution module.

[0064] The main control strategy of the low-voltage high-power DC intelligent power distribution module is as follows:

[0065] When the load current is less than 1.1 times the rated current, the DC intelligent power distribution module operates stably for a long time;

[0066] When the load current is 1.1 times the rated current, the DC intelligent power distribution module operates stably for 1h and then is protected, cutting off the power distribution branch and uploading the fault information;

[0067] When the load current is greater than 1.1 times the rated current and less than 1.25 times the rated current, it enters the first-stage I 2 t inverse time limit protection curve; the greater the load current, the shorter the inverse time delay;

[0068] When the load current is 1.25 times the rated current, the DC intelligent power distribution module operates stably for 3min and then is protected, cutting off the power distribution branch and uploading the fault information;

[0069] When the load current is greater than 1.25 times the rated current and less than the hardware current limiting value I limit When, it enters the second-stage I 2 t inverse time limit protection curve, the greater the load current, the shorter the inverse time delay;

[0070] When the load current is greater than the hardware current limiting threshold I thWhen (3.5 times the rated current), the hardware control circuit makes a judgment within microseconds, the control module enters the current limiting mode, operates at constant current, and limits the load current to the set current limiting value I limit , and at the same time starts to judge the short - circuit fault, compares the real - time detected value of the output voltage with the preset voltage curve. If the output voltage cannot follow the preset voltage curve and is close to 0, it is determined that there is a short - circuit fault in the distribution branch, quickly cuts off the distribution branch and uploads the fault information; if the output voltage gradually increases but still cannot follow the preset voltage curve after the current limiting time exceeds the set threshold T th , it is determined that the subsequent load exceeds the load - carrying capacity of the resistive - capacitive impact load of the module, cuts off the distribution branch and uploads the fault information; if the output voltage follows the preset voltage curve and the load current gradually decreases within the set time, the current limiting mode is exited and the normal working state is entered. If the hardware current limiting fails, software protection is executed. When it is detected that the load current is greater than or equal to the current limiting value I limit , the distribution branch is cut off after a 10 - ms delay and the fault information is uploaded;

[0071] When the load current is greater than or equal to 4 times the rated current, immediate tripping protection is executed, the distribution branch is cut off and the fault information is uploaded.

[0072] Specifically, it is shown in the following table.

[0073]

[0074]

[0075] Figure 2 As shown, it is the I 2 t inverse - time - limit sectional protection curve. The parameters of the sectional protection curve can be realized and set online through the upper computer, greatly improving the load adaptability.

[0076] Figure 3 It is a schematic diagram of the current - limiting control strategy for entry / exit. I cs is the hardware - detected current, and LimitON is the current - limiting control signal. The entry / exit current - limiting control is realized by using the hysteresis comparison strategy. When I cs is greater than 3.5 times the rated current, the hardware control circuit makes a judgment within microseconds, and the current - limiting control signal LimitON becomes effective (changes to high level), and the module enters the current - limiting mode; when I cs is less than 1.5 times the rated current, the current - limiting control signal flips (changes to low level), and the module exits the current - limiting mode.

[0077] Figure 4 It is the schematic diagram of the current - limiting control circuit.

[0078] To ensure a quick entry into the current - limiting state under the condition of large - current impact, a proportional - regulation circuit is adopted. In the figure, V ifThe current feedback signal measured for the detection resistor is amplified by the conditioning circuit composed of U1, R1, R2, R3, and R4. The proportional regulation circuit is composed of U2, R5, R6, R7, and R8. V ref After voltage division, it is connected to the non-inverting input terminal of U2 as the reference voltage for maintaining the current. The output of U2 is the current limiting control voltage. Q1 is a solid-state switch. When the current limiting control signal is valid, Q1 conducts, and the current limiting control voltage is output to the control voltage connection terminal of the power MOSFET through the selected diode D1. At this time, the control voltage V c Is connected to the gate of the power MOSFET through the drive circuit to control the power MOSFET to enter the linear region and limit the load current to the set value.

[0079] The reference voltage for maintaining the current is selected according to the transfer characteristic curve of the power MOSFET. When the power MOSFET is in the linear region, the current I passing through the MOSFET D Is linearly related to the control voltage V GS And is independent of its drain-source voltage V DS Therefore, when the current passing through the MOSFET is greater than the set current limiting value, the control voltage output by the proportional regulation will become smaller and finally stabilize at a certain point on the transfer characteristic curve corresponding to the set current limiting value, and the control current will be maintained at the set current limiting value until the current limiting control signal is released.

[0080] Figure 5 Figure 17 shows the test waveform of the sudden application of a resistive-capacitive impact load. It can be seen from the figure that when a resistive-capacitive impact occurs, the power distribution module can enter the current limiting mode in the microsecond level, control the load current to the set value, and the bus voltage is basically stable. Figure 6 Figure 19 shows the test waveform when the power distribution branch is short-circuited. It can be seen from the figure that when a short circuit occurs, the power distribution module can also enter the current limiting mode in the microsecond level and quickly cut off the faulty branch after judgment. The marine low-voltage DC intelligent power distribution control strategy with current limiting function proposed by the present invention can quickly, accurately, and reliably identify the load status and meet the use requirements.

[0081] The present invention is used to distribute the power supply of the centralized power supply system to the powered load, and at the same time, it can monitor the working status of the power supply, the powered load, and itself in real time, realize protection and alarm under fault conditions, and conduct information interaction with the upper-level monitoring system through the CAN bus to realize remote on-off control, online parameter setting, and remote reset after fault removal under normal conditions. In addition, it has the ability of fast current limiting under large current impact loads and fast breaking under short circuit faults. Compared with traditional power distribution devices, it has the characteristics of intelligent load management, fast fault response, and minimum fault impact. Its output current rating can be programmed for online setting and is applicable to all power distribution occasions with a rated current of 100 A or less (including 100 A) in the marine 24 V / 27 V low-voltage DC power distribution system.

Claims

1. A control strategy for a marine low-voltage high-power DC intelligent power distribution module, which is applied to a marine low-voltage high-power DC intelligent power distribution module, and is characterized in that: A marine low-voltage high-power DC intelligent power distribution module includes a power circuit, a buffer circuit, a detection circuit, a control circuit, a drive circuit and an auxiliary power supply; The power circuit includes power devices and is used to distribute the power supply of the centralized power supply system to the powered loads; The buffer circuit includes a capacitor C1 and a TVS diode to reduce the voltage spikes caused by line stray inductance and the surge voltage in the system, and protect the power devices and loads from voltage impacts; The detection circuit includes a detection resistor, a thermistor and a signal conditioning circuit, which realizes the acquisition and conditioning of the input and output voltages, load current and operating temperature, and feeds back to the control circuit; The control circuit includes a working state evaluation unit, an on-off control unit, a fault diagnosis unit, a current limiting unit and a communication unit. According to the parameters provided by the detection circuit, it judges the working states of the power supply, power distribution branch and itself, issues control instructions to the drive circuit, and uploads the operating state and working parameters to the monitoring system in real time; The drive circuit is used to receive the control signal provided by the control circuit, realize power amplification, and drive the power devices to act; The auxiliary power supply is used to provide auxiliary power supply for each functional circuit of the DC intelligent power distribution module; When the load current is less than 1.1 times the rated current, the DC intelligent power distribution module operates stably for a long time; When the load current is 1.1 times the rated current, the DC intelligent power distribution module operates stably for 1 h and then is protected, the power distribution branch is cut off and the fault information is uploaded; When the load current is greater than 1.1 times the rated current and less than 1.25 times the rated current, it enters the first stage I 2 Inverse time protection curve The larger the load current, the shorter the inverse time delay; When the load current is 1.25 times the rated current, the DC intelligent power distribution module operates stably for 3 min and then is protected, the power distribution branch is cut off and the fault information is uploaded; When the load current is greater than 1.25 times the rated current and less than the hardware current limit value I limit , it enters the second-stage I 2 t inverse time protection curve. The greater the load current, the shorter the inverse time delay time; When the load current is greater than the hardware current limit threshold I th , the hardware control circuit makes a judgment in the microsecond level, the control module enters the current limit mode, operates at a constant current, and limits the load current to the set current limit value I limit . At the same time, the short - circuit fault judgment is started, and the real - time detected value of the output voltage is compared with the preset voltage curve. If the output voltage cannot follow the preset voltage curve and approaches 0, it is determined that there is a short - circuit fault in the distribution branch, and the distribution branch is quickly cut off and the fault information is uploaded; if the output voltage gradually increases but still cannot follow the preset voltage curve after the current - limiting time exceeds the set threshold T th , it is determined that the load at the rear stage exceeds the load - carrying capacity of the resistive - capacitive impact load of the module, the distribution branch is cut off and the fault information is uploaded; if the output voltage follows the preset voltage curve and the load current gradually decreases within the set time, the current - limit mode is exited and the normal working state is entered; If the hardware current limit fails, software protection is executed. When the detected load current is greater than or equal to the current limit value I limit , cut off the power distribution branch after a 10 ms delay and upload the fault information; among them, the hardware current limit threshold I th is 3.5 times the rated current; When the load current is greater than or equal to 4 times the rated current, immediate tripping protection is executed, the power distribution branch is cut off and the fault information is uploaded.

2. The control strategy of a marine low-voltage high-power DC intelligent power distribution module according to claim 1, characterized in that: The power circuit includes power devices, a power resistor R1, a DC power input terminal and a DC power output terminal; The power devices are composed of high-power, low on-state impedance MOSFETs connected in parallel. The drain of the MOSFET is connected to the DC power input terminal, the source is connected to the DC power output terminal through a detection resistor Rs, and the gate is connected to the output terminal of the drive circuit; The power resistor R1 is connected between the DC power output terminal and the power ground, and is used to eliminate the floating voltage at the output terminal when the DC intelligent power distribution module is turned off.

3. A control strategy for a marine low-voltage high-power DC intelligent power distribution module according to claim 1, characterized in that: The buffer circuit includes a decoupling capacitor C1, a high-power TVS diode Z1 and a high-power TVS diode Z2; The decoupling capacitor C1 uses an aluminum electrolytic capacitor and is connected between the DC power input terminal and the power ground; The TVS diode Z1 is connected in parallel with the drain and source of the power MOSFET; The TVS diode Z2 is connected between the DC power output terminal and the power ground.

4. The control strategy of a marine low-voltage high-power DC intelligent power distribution module according to claim 1, characterized in that: The detection circuit includes a detection resistor Rs, a thermistor and a signal conditioning circuit; the detection resistor Rs uses a high-power, high-precision surface-mounted shunt, one end is connected to the source of the power MOSFET, and the other end is connected to the DC power output terminal; The signal conditioning circuit is composed of high-speed operational amplifiers.

5. The control strategy of a marine low-voltage high-power DC intelligent power distribution module as described in claim 1, characterized in that: The control circuit adopts digital and analog hybrid control, including a working state evaluation unit, a switching control unit, a fault diagnosis unit, a current limiting unit and a communication unit, which are used to realize slow turn-on and slow turn-off under normal working conditions, intelligent distinction between large current impact loads and short-circuit working conditions, current limiting and protection, and I 2 t inverse time limit protection function, and at the same time, it uploads the working state, operating parameters and fault information in real time.

6. The control strategy of a marine low-voltage high-power DC intelligent power distribution module as claimed in claim 5, characterized in that: The digital control part of the control circuit adopts a minimum system based on DSP to achieve on-off control, communication, and input over- and under-voltage, over-temperature, and I 2 t inverse time definite-time protection; The analog control part uses high-speed operational amplifiers and logic devices to achieve hardware current limiting control and fast disconnection control in case of short-circuit faults.

7. The control strategy of a marine low-voltage high-power DC intelligent power distribution module according to claim 6, characterized in that: The hardware current limiting control adopts a proportional regulation circuit. The conditioning circuit composed of the high-speed operational amplifier U1 and resistors R1, R2, R3, and R4 amplifies the current feedback signal. The proportional regulation circuit is composed of the high-speed operational amplifier U2 and resistors R5, R6, R7, and R8. V ref After voltage division, it is connected to the non-inverting input terminal of the high-speed operational amplifier U2 as the reference voltage for maintaining the current. The output of the high-speed operational amplifier U2 is the current limiting control voltage. The output terminal of the high-speed operational amplifier U2 is connected to the gating diode D1 through the solid-state switch Q1.

8. The control strategy of a marine low-voltage high-power DC intelligent power distribution module according to claim 1, characterized in that, The strategies of the hardware current limiting control include: The hysteresis comparison strategy is adopted for entering / exit current limiting control. When the load current is greater than 3.5 times the rated current, a judgment is made in the microsecond level, and the current limiting control signal takes effect, and the module enters the current limiting mode; when the load current is less than 1.5 times the rated current, the current limiting control signal fails, and the module exits the current limiting mode. In the current limiting mode, by using the output characteristics of the power MOSFET itself and controlling the driving voltage, the load current is limited to a set value.

9. The control strategy of a marine low-voltage high-power DC intelligent power distribution module according to claim 1, characterized in that, The strategies for distinguishing between large current impact loads and short-circuit conditions include: An RC network is used to simulate the charging curve of the resistive-capacitive impact load, and the output voltage of the DC intelligent power distribution module is detected in real time. In the current limiting mode, a current limiting duration is set. The detected value of the output voltage is compared with the simulated charging curve. If the output voltage still cannot follow the simulated charging curve when the current limiting time exceeds the set threshold, it is determined that the subsequent load exceeds the load-carrying capacity of the resistive-capacitive impact load of the module or a short-circuit fault occurs in the power distribution branch; if the output voltage follows the simulated charging curve and the load current gradually decreases within the set time, the current limiting mode is exited and the normal working state is entered.

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