61 results about "DC distribution system" patented technology

The invention relates to the technical field of power electronics and power supply and distribution, and discloses a data center AC / DC power distribution system input and output voltage and current monitoring method, which comprises the following steps: deploying an intelligent sensing unit with edge computing capability at each monitoring node, sampling according to a basic frequency, and extracting effective values, harmonic distortion rates, differential change rates and other characteristics of voltage and current in real time; judging that the system is in a steady state, a quasi transient state or a strong transient state according to the multi-stage dynamic threshold value, and respectively executing feature abstract uploading, local high-frequency backtracking or collaborative full-waveform synchronous acquisition; and the central server classifies and stores the data, constructs a state evolution model, and dynamically optimizes threshold parameters. The system comprises an intelligent sensing unit, a central monitoring server and an industrial Ethernet link. According to the method, the steady-state data transmission quantity is remarkably reduced, transient details are completely captured, and adaptive adjustment of the monitoring sensitivity is realized.

This invention discloses an active damping control method for bipolar DC distribution systems based on modulus decomposition. It incorporates line coupling into the system's stability criteria and active damping parameter design, deriving the pole-mode transformation matrix of the metal-return bipolar DC distribution system and obtaining a decoupling model of the bipolar DC line in the modulus component space. The modulus models of the source-side converter and load are also derived. Based on the established decoupling model of the bipolar DC distribution system in the modulus component space, an active damping control method based on modulus decomposition is proposed. This invention considers the impact of DC distribution lines on stability, incorporating line coupling into the system's stability criteria and active damping parameter design. The modulus damping control scheme proposed in this invention can more effectively suppress instability caused by the negative impedance characteristics of constant power loads and also provides a basis for parameter adjustment.

The application provides a DC power distribution network source-load-storage self-adaptive power distribution method based on flexible droop control, aiming at coordinating the logical relationship between the maximum power constraint of new energy, the residual capacity constraint of energy storage equipment and the controllable range constraint of load and the voltage-power droop control in the DC power distribution network, meanwhile, the application determines a droop coefficient setting method in the form of power standard, provides a unified droop coefficient setting rule for equipment of different categories, capacities and rated powers, and ensures that each equipment can determine the quota participating in the self-adaptive power distribution according to the current working condition under the droop coefficient setting scheme, compared with the existing scheme, the self-adaptability of the power distribution among the source, the load and the storage in the DC power distribution system is improved.

The application discloses a kind of grid-connected detection method, equipment, medium and product of AC-DC distribution system, the method includes: establishing the power flow model of AC-DC distribution system before distributed power grid connection, and according to power flow model obtains time series power flow result, the reliability calculation of AC-DC distribution system is carried out, obtains reliability calculation index, according to time series power flow result and reliability calculation index, the comprehensive performance index of AC-DC distribution system is constructed, according to comprehensive performance index, the operation state information of AC-DC distribution system is generated for distributed power grid connection.According to operation state information, the weak link that AC-DC distribution system needs to be reformed can be determined, and technical support and guidance can be provided for distributed power grid connection strategy, which is conducive to promoting the safe and reliable operation of AC-DC distribution system.Through optimization scheduling and power supply planning, the operation efficiency of AC-DC distribution system can be improved, the operation cost is reduced, and the accuracy of grid-connected detection of AC-DC distribution system is improved.

The embodiment of the invention provides a mining DC power distribution system. In one specific embodiment, the system comprises a rectification filtering unit, an energy storage assembly, a first power-off change-over switch, a second power-off change-over switch, relay power generation equipment and a controller. The controller is used for acquiring a first conversion state of the first power-off automatic conversion switch, responding to the first conversion state as an instruction that the output end of the first power-off automatic conversion switch is connected with the standby input end, controlling the power generation equipment to be started, acquiring an operation state of the power generation equipment, responding to the operation state as an operation ready instruction, and controlling the power generation equipment to be started. And the coil of the relay is controlled to be electrified. The mining DC power distribution system can stably and continuously supply power for a long time.

The present application relates to the field of power electronics and power supply and distribution technology, and discloses a monitoring method for input and output voltage and current of an AC / DC power distribution system in a data center, which comprises: deploying intelligent sensing units with edge computing capabilities at each monitoring node to sample at a basic frequency and extract real-time characteristics such as effective value, harmonic distortion rate and differential change rate of voltage and current; determining whether the system is in a steady state, quasi-instantaneous state or strong instantaneous state according to multi-level dynamic threshold values, and performing feature abstract upload, local high-frequency backtracking or collaborative full-waveform synchronous acquisition respectively; storing data in a central server and constructing a state evolution model to dynamically optimize threshold parameters. The system comprises intelligent sensing units, a central monitoring server and an industrial Ethernet link. The present application significantly reduces steady-state data transmission volume, completely captures transient details and realizes adaptive adjustment of monitoring sensitivity.

The application provides a Kun-type hybrid polarity direct current power distribution system and a four-transformer QAB converter h1 The positive pole of the high-voltage side bus is connected to the high-voltage side active bridge H l1 The positive pole of the low-voltage side bus is connected to the high-voltage side active bridge H h2 The negative pole of the high-voltage side bus is connected to the low-voltage side active bridge H l2 The negative pole of the low-voltage side bus is connected to the high-voltage side active bridge H h1 The high-voltage side active bridge H l1 is connected to the low-voltage side active bridge H r1 through a high-frequency transformer T h2 The high-voltage side active bridge H l2 is connected to the low-voltage side active bridge H r2 through a high-frequency transformer T l1 The low-voltage side active bridge H h2 and the high-voltage side active bridge H e1 are connected through a transformer T h1 The low-voltage side active bridge H l2 and the high-voltage side active bridge H e2 are connected through a transformer T The Kun-type hybrid polarity direct current power distribution system provided by the application has the function of true bipolar system interconnection and guarantees electrical isolation between bipolar systems, thereby ensuring the safety of user power supply.

The application provides a method and system for simulating operation of a direct current power distribution system with an energy storage device, comprising: setting an initial value of a direct current voltage in the direct current power distribution system; reading a control mode of a voltage source converter and the energy storage device in the direct current power distribution system and a state of charge of the energy storage device; adjusting the control mode of the voltage source converter and the energy storage device according to the initial value of the direct current voltage in the direct current power distribution system and the state of charge of the energy storage device; and performing power flow simulation calculation on the power distribution system after the control mode of the voltage source converter and the energy storage device is adjusted. The method and system can effectively cope with the characteristics of the energy storage device in the direct current power distribution system, such as the changeable state of charge and the flexible adjustment of the control mode, and meet the power flow calculation requirements of the direct current power distribution system with the energy storage device.

The invention provides a DC micro-grid insulation resistance monitoring device for an optical storage DC flexible system. The DC micro-grid insulation resistance monitoring device comprises a detection circuit and a controller communicating with the detection circuit. The device is connected to multiple paths of positive direct current buses including distributed photovoltaic branches and energy storage system branches in a direct current micro-grid through a Y-shaped connecting circuit, and relay logic is switched by utilizing a controller to obtain an output voltage signal. The core judgment logic is to compare whether the output voltage is in a reasonable interval defined by a coefficient gamma (the value can be dynamically adjusted according to the energy storage voltage grade) and the bus voltage, so that the insulation abnormity of the direct current micro-grid system under the flexible interaction working condition is quickly identified, and an alarm is given. According to the device, the operation process of multi-branch complex impedance is simplified, and the detection efficiency of the ground insulation state of the direct current end is remarkably improved.

The invention relates to a temperature control system control method and device, computer equipment and a storage medium, and relates to the technical field of temperature control. The method comprises the following steps: acquiring the bus voltage of a direct current power distribution system of a building where the temperature control system is located and the state information of the temperature control system, and determining the set temperature of the temperature control system by using a prediction model of the temperature control system according to the bus voltage and the state information; wherein model parameters of the prediction model are respectively related to the temperature control system and the building where the temperature control system is located, the temperature control system is controlled according to the set temperature, and the output power after the temperature control system is controlled is smaller than the output power when the temperature control system starts to be controlled. By adopting the method, flexible operation of the temperature control system can be controlled, power consumption is reduced, and the purposes of low power consumption and low carbon are achieved.

The application discloses a direct current system grounding fault detection method and system, equal resistance is connected between the positive and negative bus of the direct current system and the ground to form a symmetrical resistance network, the positive / negative ground voltage and the branch ground current are collected in real time, the voltage deviation is calculated to generate a time domain fault mark, a high frequency component is extracted by wavelet transform and energy entropy analysis to generate a frequency domain mark, the ground current signal is subjected to wavelet transform and energy entropy calculation to extract a high frequency detail component, hierarchical collaborative decision is executed, double mark triggering immediately trips, single mark triggering starts a delay review mechanism, and after continuous triggering, tripping is executed and fault positioning and reporting are performed. The technical system improves the comprehensive identification speed of the direct current system grounding fault, forms a whole-process closed-loop protection of fast sensing and identification, reliable decision and accurate positioning, and improves the operation safety of the direct current distribution system.

The invention discloses a direct-current power distribution system energy mutual aid and power coordination control method, application and system, aiming at non-ideal disturbance, load fluctuation and parameter uncertainty existing in the system, VFESO is introduced, rapid estimation and compensation of generalized disturbance are realized through self-adaptive adjustment of observation gain and feedback bandwidth, and based on an observation result of the VFESO, the energy mutual aid and power coordination control of the direct-current power distribution system is realized. An improved reference feed-forward control law is designed, the reference current change rate and the disturbance observed quantity are comprehensively considered in the control law, a disturbance compensation item is directly introduced into control input, and feed-forward compensation and dynamic linearization of a current control loop are achieved; according to the invention, the system can maintain high-precision voltage and power control under the conditions of new energy fluctuation, energy storage switching and load disturbance.

The invention relates to a solid-state switch fault protection system for a direct-current power distribution system, which is applied to a ship direct-current power distribution system, the ship direct-current power distribution system comprises a direct-current bus, the direct-current bus is divided into a left direct-current bus and a right direct-current bus, and the left direct-current bus and the right direct-current bus are connected through a solid-state switch. The solid-state switch fault protection system comprises an energy management system, a converter and the like which are connected with a ship direct-current power distribution system, a power supply is connected with a direct-current bus through the converter, a propelling system is connected with the direct-current bus through a motor driver module, and a side propelling system is connected with the direct-current bus through a power inverter module. The energy management system adopts a redundant PLC control system based on a looped network so as to quickly monitor faults of the solid-state switch, and can quickly provide a control scheme according to an online system. In addition, the system has the advantages of good stability, safety and the like.

The application relates to the technical field of shell circuit breakers, and provides a compact DC molded case circuit breaker and a DC power distribution system. The compact DC molded case circuit breaker comprises a shell, an operating mechanism and an arc extinguishing module, two arc extinguishing cavities are arranged in the shell, the operating mechanism comprises an operating unit and a first rotating shaft which are connected with each other, one end of the operating unit is located outside the shell, the first rotating shaft is located in the shell, and the operating mechanism is located between the two arc extinguishing cavities; the arc extinguishing module is arranged in each arc extinguishing cavity, the arc extinguishing module comprises a second rotating shaft, a first grid group, a second grid group, a third grid group and a contact assembly, the first grid group and the second grid group are oppositely arranged on the two sides of the contact assembly, the third grid group is arranged on one side of the contact assembly, and the first grid group, the second grid group, the third grid group and the contact assembly form a leaving area for accommodating the contact assembly. The application can maximize the arc extinguishing cavity volume and the wiring space within a specific width.

The invention relates to the technical field of building direct-current power supply and distribution and power electronic control, and discloses a double-ring multi-module phase-shifting soft switching coordination control method, system and device for a B2G converter and a medium, and the method comprises the steps: achieving the performance optimization of the B2G modular converter in a steady-state, high-dynamic and wide-load range through a pure software control means. On the premise that the hardware topology is not changed, the full load efficiency of the system reaches 97% or above, and the efficiency is reduced by less than 2% when the load is 20%. The DC bus voltage is stable during load fluctuation, the controllable transition time is very short, and no impact current or overvoltage exists during bidirectional power switching; the power modules are balanced in heating, stress is reduced, and overall reliability is improved. The control strategy can be widely applied to current conversion equipment of an optical storage DC flexible DC power distribution system, and has remarkable popularization potential.

This invention discloses an adaptive DC voltage control method for a three-terminal flexible DC distribution system, belonging to the field of power technology. The method includes the following steps: constructing a three-terminal flexible DC distribution system; analyzing the deviation value of the DC voltage in the three-terminal flexible DC distribution system; determining the magnitude of the DC voltage deviation value; and controlling the change and voltage value of the DC voltage in the three-terminal flexible DC distribution system. This invention superimposes an active power command correction controller onto the constant power control mode (PQ mode) of the flexible DC converter, enabling the flexible DC converter to dynamically adjust the output active power according to the instantaneous state of the DC voltage, thereby improving the DC voltage recovery speed.

The application discloses a kind of topology circuit, device and method of active promotion equipment of direct current power supply quality, circuit includes: double active converter DAB and direct current active filter DC-APF;Device includes direct current distribution system power quality management circuit and control module;Method includes: real-time detection whether there is voltage deviation and direct current ripple condition;When detecting voltage deviation, control the conduction of diagonal switch tube in first DC-APF and second DC-APF;When detecting direct current ripple, control first DC-APF and second DC-APF output reverse compensation current to suppress ripple;The application can realize voltage, harmonic self-regulating coordination, with direct current ripple management, voltage deviation suppression capability.

The invention relates to a flexible interconnection device-based self-adaptive multi-target cooperative scheduling method for a power distribution area, and belongs to the technical field of electric power. The method takes minimization of voltage fluctuation and flexible load fluctuation of an AC / DC power distribution system as a target, an optimization target function is constructed, and meanwhile, SOP power constraint, system power flow constraint, system operation safety constraint, energy storage constraint and flexible load constraint are taken as constraint conditions; dividing the operation mode of the transformer area, and then respectively constructing dynamic weight coefficients in a steady-state operation mode, a voltage early warning mode and a secondary voltage recovery mode; and solving the optimization objective function, and scheduling according to a solving result. According to the method, multi-target collaborative optimization is realized, and the economic operation and source load fluctuation impact coping capability of each transformer area in the power distribution transformer area are improved; by detecting voltage fluctuation in real time, the adjusting function of a controllable device can be fully played, the system power flow can be rapidly and accurately adjusted, and economical and reliable operation of the system is achieved.

The application discloses a three-phase grid-connected converter control method, a circuit, a device and a medium, and relates to the technical field of AC-DC power distribution systems. The three-phase grid-connected converter control method provided by the application establishes a mathematical model of the three-phase grid-connected converter, combines the causes and suppression mechanism of the leakage current, controls the filter capacitor voltage in the zero sequence loop to be a constant value through a PI regulator, and effectively attenuates the leakage current. The phase angle of the grid voltage is obtained in a three-phase stationary coordinate system, the sampling quantity is coordinate-transformed according to the angle, a modulation signal is obtained, and the power switch tube in the grid-connected converter is controlled according to the modulation signal. Since only one connected wire needs to be added between the middle point of the filter capacitor and the common point of the lower bridge arm in the scheme, the cost is low, and the leakage current caused by the existence of the parasitic capacitance of the DC side power distribution device to the ground can be limited to the microampere level.

This DC power distribution system supplies power from power supplies (20, 21) through a DC bus (2) to a plurality of devices (23, 24, 25, 26) in a logistics warehouse, and comprises: first power converters (10, 11) that supply power unidirectionally from the power supplies (20, 21) toward the DC bus (2); second power converters (13, 14, 15) that supply power bidirectionally between the DC bus (2) and built-in storage battery loads (23, 24, 25); a third power converter (16) that supplies power bidirectionally between the DC bus (2) and a motor load (26); and a control device (1) that instructs the first power converters (10, 11) and the second power converters (13, 14, 15) to transmit a target voltage value on the DC bus side and operation parameters being the power conversion directions.

The invention discloses a DC power distribution network interelectrode short circuit protection method and system based on boundary elements, and belongs to the technical field of DC power distribution system protection. The method comprises the following steps: configuring a capacitor as a boundary element at the tail end of a DC line protection area; current is collected in real time, the change rate is calculated, and protection is started if a threshold value is exceeded; performing high-speed sampling on the current after starting; performing wavelet transform on the sampled data, and extracting high-frequency energy and low-frequency energy of the current; and calculating a high-frequency and low-frequency energy ratio, if the ratio is greater than a preset threshold value, determining that an intra-region inter-electrode short-circuit fault occurs and a tripping instruction is sent out, otherwise, determining that the intra-region inter-electrode short-circuit fault occurs or no fault occurs. According to the method, the bypass effect of the boundary capacitance on the high-frequency fault current is utilized, the obvious characteristic difference of the internal and external faults of the area is manufactured, the difference is quantified through wavelet transform, rapid and accurate fault recognition and isolation based on local quantity without depending on communication are achieved, and the problem that in the prior art, quickness and selectivity are difficult to consider at the same time is solved.

The utility model belongs to the technical field of ship power distribution, and specifically discloses a marine double-bus redundant DC power distribution system. Comprising a first direct-current busbar left, a first direct-current busbar right, a second direct-current busbar left, a second direct-current busbar right, a first circuit breaker, a second circuit breaker, a lithium battery pack, a first propulsion inverter cabinet, a first daily inverter cabinet, a second propulsion inverter cabinet, a second daily inverter cabinet, a direct-current voltage stabilizer and a system charging socket box. According to the utility model, through setting the first direct-current busbar left, the first direct-current busbar right, the second direct-current busbar left, the second direct-current busbar right and the switching relation thereof and adopting an operation mode that one group of busbars works and the other group of busbars is standby, flexible and balanced distribution of a power supply and a load is realized, and all loops can work without power failure; once any busbar or branch has a fault, the standby busbar is immediately started so as to start the standby loop, so that no power loss and no power reduction of the whole ship are ensured, and all equipment and components of the whole system are subjected to redundancy design so as to ensure that the power distribution system always supplies power normally.

The application provides a K-type hybrid polarity direct current power distribution system, comprising: a high-voltage side bipolar bus, a low-voltage side bipolar bus, a converter part for connecting the high-voltage and low-voltage power distribution networks, and a high-voltage and low-voltage bipolar direct current shared neutral line; the converter part is composed of a four-port active bridge (QAB) converter and a power direct transmission line; a positive high-voltage side active bridge of the converter part is composed of four MOSFET switch tubes S11, S12, S13 and S14 and four anti-parallel diodes D11, D12, D13 and D14, and a low-voltage side active bridge is composed of switch tubes S21, S22, S23 and S24 and diodes D21, D22, D23 and D24; the high-voltage side active bridge and the low-voltage side active bridge are connected through a high-frequency transformer with a turns ratio n of 1:1, the equivalent leakage inductance of the transformer is Lr1, and the negative pole has the same structure as the positive pole. The application has the ability to interconnect direct current systems of different voltage levels and transmit part of the power of high-voltage and low-voltage direct current systems, and has the load access selection of five voltage levels of ±2VDC, 4VDC and ±VDC at the same time, and the operation mode is flexible.

The application discloses a kind of based on truncation coefficient and realizes state merging DC distribution system reliability evaluation method, it is related to DC distribution system field.According to the multiple operating states presented by the coupling of DC distribution system "source load", the system state space model is established, according to the internal relationship between different operating states, the state merging condition is optimized, the fault tree analysis method is combined with Markov process, the state merging method based on truncation coefficient is proposed, and the reliability index of DC distribution system is calculated according to the system operating state after merging.The application first applies the state merging idea to the reliability evaluation of DC distribution system, combines the fault tree analysis method with Markov process, determines the truncation coefficient by the convergence process of truncated state probability C While ensuring accuracy, the solving efficiency of merged state transition rate is improved, the system state merging under differentiated transition rate is realized, and the application range of state merging in the reliability evaluation of DC distribution system is expanded.

The invention belongs to the technical field of power distribution in a nuclear power plant, and particularly relates to a direct-current power distribution system applied to the nuclear power plant, which comprises at least two direct-current topological power distribution lines used for accessing different high-voltage alternating-current power supplies outside the plant, and each direct-current topological power distribution line comprises a shared rectifier and two sub-power distribution lines. Each sub-distribution line is provided with a DC bus of a first distribution voltage, a DC bus of a second distribution voltage, DC buses of two third distribution voltages and a standby DC bus of a third distribution voltage. The first direct current bus and the second direct current bus of the third power distribution voltage are used for providing direct current of the third power distribution voltage for the in-plant load and providing alternating current of the third power distribution voltage through the inverter; one end of the rectifier is used for accessing an off-plant high-voltage AC power supply, and the other end is connected to the DC bus of the two first distribution voltages.

The application discloses a kind of multi-dimension multi-resource comprehensive voltage regulation optimization methods of multi-voltage grade bipolar direct current distribution network, comprising:1 establishes the control model of bipolar direct current transformer DCT, electric vehicle, energy storage equipment and power flow controller;2 establish multi-dimension multi-resource coordinated control model of multi-voltage grade bipolar direct current distribution network;3 establish comprehensive voltage regulation optimization model of multi-voltage grade bipolar direct current distribution network;4 establish the linearization and relaxation model of the constraint of bipolar direct current distribution network comprehensive voltage regulation model;5 by solving multi-voltage grade bipolar direct current distribution network, obtain the comprehensive voltage regulation optimization strategy of bipolar direct current distribution system.The application can realize the quick response load demand and distributed energy fluctuation, ensure the stability of low-voltage side voltage, effectively control the voltage imbalance degree and over-limit problem between positive and negative electrode, improve the stability of system voltage.

The invention discloses an AC / DC power distribution system typical scene generation method considering source-load space-time correlation, and relates to the technical field of scene generation, and the method comprises the steps: building a digital representation model based on the typical grid topology of an AC / DC power distribution system; according to new energy spatio-temporal evolution characteristics, constructing a time correlation model of wind and light output based on a dependency function-state transition chain, and establishing a spatial correlation model of wind and light output based on a multivariate hierarchical tree; constructing a load time sequence optimization model driven by a daily load characteristic index according to the random volatility of the daily load, and constructing a charging load generation model according to different user groups of the electric vehicle; establishing a flexibility demand and supply quantification model; and constructing an original scene according to the established model, and clustering the generated original scene to obtain a typical scene of the AC / DC power distribution system. According to the method, the source-load space-time correlation can be extracted based on historical data, the original scene is generated, and the typical scene is obtained through clustering.

The application provides a low-voltage transfer protection device for the end of a DC power supply line of rail transit, comprising a voltage transmitter A, a voltage transmitter B, a low-voltage protection measurement and control unit and a transfer cable, the input end of the voltage transmitter A is connected with the positive pole and the negative pole of the end of the DC power supply line respectively, and the output end is connected with the low-voltage protection measurement and control unit, the input end of the voltage transmitter B is connected with the positive pole of the end of the DC power supply line and the ground wire respectively, and the output end is connected with the low-voltage protection measurement and control unit, and the output end of the low-voltage protection measurement and control unit is connected with the DC distribution system in the traction substation through the transfer cable. And a protection method, whether the voltage measured by the two voltage transmitters exceeds the setting value is judged respectively, if the setting value is exceeded, the DC distribution system controls the corresponding line circuit breaker to transfer. The application significantly improves the reliability, speed and sensitivity of the over-current protection of the DC line, reduces the engineering investment and the operation and maintenance cost.

A pre-charge circuit for charging a DC link capacitor is provided. The pre-charge circuit may include: a first semiconductor switch for coupling to a first terminal of a high-voltage source; a first inductor for coupling to the first semiconductor switch and the first terminal of the capacitor; a second semiconductor switch for coupling to a second terminal of the high-voltage source; a second inductor for coupling to the second semiconductor switch and the second terminal of the capacitor; and a diode coupled to the first semiconductor switch, the second semiconductor switch, the first inductor, and the second inductor, and coupled in parallel with the capacitor.

The invention discloses a low-voltage flexible DC micro-grid fault positioning method based on an improved Tiancattle swarm algorithm. According to the method, the fault point can be accurately positioned when the inter-electrode short-circuit fault or the single-electrode grounding fault occurs in the flexible direct-current power distribution network. The method is slightly influenced by excessive resistance, and a fault positioning problem is converted into a fault parameter identification problem. And in combination with the improved Tiancattle swarm algorithm, the accuracy of fault point positioning can be improved, errors are reduced, and the information distortion resistance is improved. The method is of great significance in improving the safety and reliability of the direct-current power distribution system.