Multi-level network construction type energy storage control protection system

Abstract

The invention relates to the technical field of energy storage control protection, and discloses a multi-level network-forming type energy storage control protection system, which comprises a battery management unit, an energy management unit, a main control protection unit, a valve base control protection unit and a sub-module control unit, the invention relates to a plurality of key technologies, in particular to a multi-level net-forming type energy storage control and protection system which comprises control strategy generation of an energy management unit, modulation wave generation of a main control and protection unit, SOC balance control strategy of a valve base control and protection unit, maintenance instruction generation of a sub-control and protection unit and thermal management and safety strategy of a battery management unit. Through the comprehensive application of the technology, the multi-level network construction type energy storage control and protection system can realize efficient operation and value creation of the energy storage system in a novel power system on the basis of ensuring the safety and the quality.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage control and protection, and in particular to a multi-level networked energy storage control and protection system. Background Art

[0002] The multi-level grid-type energy storage control and protection system is a control and protection technology used in energy storage systems, aiming to improve the safety, reliability and efficiency of energy storage systems.

[0003] Under the current technological background, with the rapid development of new energy, the global power system has entered a stage of high penetration of renewable energy, which brings challenges to the stable operation of the power grid. As one of the key supporting technologies for the new power system, networking technology has become a technical highland for scientific and technological innovation in power systems of various countries. With the high proportion of new energy development, the power system faces problems such as supply and demand balance, decreased stability, fault isolation risks and broadband oscillation. Although networking technology can provide certain inertia support and frequency and voltage stability capabilities, how to ensure the long-term stability of the system in a complex power system environment is still a challenge. Summary of the invention

[0004] The present invention sends control mode information and control target value to the main control unit through the energy management unit, and receives the unit voltage and current sampling and various monitoring information sent by it. The main control unit is responsible for the overall reactive / active power control, adopts the unit-level control algorithm, and outputs the three-phase modulation wave to the valve base control unit; the valve base control unit coordinates the work of each unit in the three-phase PCS commutation chain, completes the judgment and relay of the downlink control command and the uplink status signal, completes the additional control of the battery SOC balance between each module in each phase, and finally outputs the corresponding control signal for each PCS unit; the control circuit SMC of the PCS unit receives the control signal sent by VBC, adopts the modulation algorithm, and finally generates the driving pulse signal of the power device.

[0005] In order to achieve the above object, the present invention provides a multi-level networked energy storage control and protection system, comprising:

[0006] Battery management unit, energy management unit, main control protection unit, valve base control protection unit and submodule control unit;

[0007] Among them, the battery management unit is used to obtain the operating status data of the current energy storage system;

[0008] The energy management unit is used to obtain the operating status data of the energy storage system and generate a primary control instruction based on the operating status data of the energy storage system and system requirements;

[0009] The main control protection unit is used to convert the primary control instructions generated in the energy management unit into a modulation wave;

[0010] The valve base control protection unit is used to coordinate the work of each unit in the three-phase PCS commutation chain; it is also used to generate the secondary control instructions corresponding to each PCS unit;

[0011] The sub-control protection unit is used to generate a driving pulse signal of the power device in combination with the secondary control instruction and by using a modulation algorithm.

[0012] In some embodiments of the present invention, the energy management unit is further used for:

[0013] Generate a historical operating status evaluation value based on the acquired historical operating status data of each component of the energy storage system;

[0014] Set up multiple control strategies based on historical data and historical operating status evaluation values;

[0015] Obtain the operating status data of each component of the energy storage system at the current sampling time node to generate an operating status evaluation value set P of each component of the energy storage system at the current sampling time node, where P = {P1, P2...Pi...Pn};

[0016] Wherein, Pi represents the operating status evaluation value of the i-th component in the current energy storage system;

[0017] Pi=H*(f1*Ti+f2+Vi);

[0018] Among them, H is the environmental impact coefficient, which is obtained through historical environmental data, f1 is the weight of the temperature evaluation value of the i-th component, Ti represents the temperature evaluation value of the i-th component, f2 is the load evaluation value of the i-th component, and Vi represents the load evaluation value of the i-th component;

[0019] Generate a control strategy based on the set P of operating status evaluation values ​​of each component of the energy storage system at the current sampling time node;

[0020] Generate primary control instructions based on the control strategy, including: control parameters of the current energy storage system, voltage control target and start / stop instructions of the subsequent DC / DC.

[0021] In some embodiments of the present invention, the main control protection unit is further used for:

[0022] Based on the primary control instruction, the modulation wave used for controlling each front-stage H-bridge in the current energy storage system is calculated to generate a three-phase modulation wave data set of the front-stage H-bridge;

[0023] The three-phase modulation wave data set of the front-stage H-bridge, the voltage control target and start / stop instructions of the rear-stage DC / DC are sent to the valve base control and protection unit, and the system active safety strategy is executed at the same time;

[0024] The system active safety strategy includes:

[0025] Set up multi-level fault isolation points based on battery module-battery column-battery cluster-battery stack-PCS;

[0026] The fault isolation point is a multi-stage DC fast-fuse protection device.

[0027] In some embodiments of the present invention, the valve base control and protection unit is further used for:

[0028] Receive the three-phase modulation wave sent by the main control protection unit, and generate the SOC balancing control strategy between the batteries connected to each power unit inside the valve base control protection unit based on the three-phase modulation wave;

[0029] Generating secondary control instructions based on SOC balancing control strategy includes: each H-bridge carrier, modulation wave or switching command;

[0030] And send the secondary control instructions to the sub-control protection unit.

[0031] In some embodiments of the present invention, the generating of the SOC balancing control strategy between the batteries connected to each power unit further includes:

[0032] Two-layer balancing control: the first layer is the inter-phase SOC balancing control strategy; the second layer is the intra-phase SOC balancing control strategy;

[0033] The first layer is the current control algorithm, which combines the command current, decoupling feedforward and PI control to control the centralized VSG output current to track the current command;

[0034] Combine inter-phase SOC balancing control and zero-sequence voltage injection or negative-sequence current injection to control the inter-phase SOC balancing of the ABC three-phase battery;

[0035] The second layer generates modulation waves for each module of the three phases through a single-stage frequency-doubled carrier phase-shifted SPWM modulation algorithm;

[0036] Combined with the intra-phase SOC balancing control, the intra-phase SOC balancing of the ABC three-phase battery is achieved.

[0037] In some embodiments of the present invention, the sub-control protection unit is further used for:

[0038] A corresponding sub-control protection unit is set in each PCS unit, and a driving pulse signal of the power device is generated based on the secondary control instruction and sent to the corresponding driving circuit. At the same time, a maintenance instruction of the PCS unit is generated based on the sub-control protection unit.

[0039] In some embodiments of the present invention, the generation of the maintenance instruction of the PCS unit based on the sub-control protection unit includes:

[0040] Based on the sub-control protection unit, obtain the relevant status evaluation value data set A of the device on the current PCS unit, A={A1,A2…Ai…An};

[0041] Wherein, Ai represents the relevant status evaluation value of the i-th device on the current PCS unit, and n represents the number of devices on the current PCS unit;

[0042] Setting a status evaluation value threshold for each device based on historical data, comparing the status evaluation value of the device on the current PCS unit with the corresponding threshold, and generating a status evaluation information table for the current PCS unit;

[0043] Generate maintenance instructions for the PCS unit based on the relevant status evaluation information table of the current PCS unit.

[0044] In some embodiments of the present invention, the battery management unit is further used for:

[0045] Control the opening and closing of internal circuit breakers and contactors based on the drive pulse signal, and simultaneously obtain the status monitoring data of each battery in each battery cluster and the battery's SOC / SOH information and upload them to the energy management unit;

[0046] Execute air-cooled battery thermal management strategy and battery active safety strategy.

[0047] In some embodiments of the present invention, the execution of the air-cooled battery thermal management strategy and the battery active safety strategy includes:

[0048] The thermal management strategy of air-cooled batteries is as follows:

[0049] Monitor the temperature of each battery cell of the battery module in real time, and set an air duct at each battery cell to control the temperature of each battery cell of the currently monitored battery module within the preset value range by controlling the on and off of the air duct;

[0050] Real-time monitoring of the temperature of the battery compartment and control of the temperature of the battery compartment through air cooling;

[0051] The battery active safety strategy is as follows:

[0052] The working status of the current battery module is judged based on the real-time temperature data of the current battery module, and an early warning instruction is generated based on the working status of the current battery module.

[0053] In some embodiments of the present invention, the uploading to the energy management unit includes:

[0054] Obtain battery status monitoring data and battery SOC / SOH information based on the battery management unit and upload them to the sub-control protection unit;

[0055] The sub-control protection unit obtains the H-bridge monitoring information and receives the battery status monitoring data and the battery SOC / SOH information and sends it to the valve base control protection unit;

[0056] The valve base control and protection unit sends the H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information to the main control and protection unit;

[0057] The H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information are sent to the energy management unit through the main control protection unit.

[0058] Compared with the prior art, the multi-level grid-type energy storage control and protection system provided by the embodiment of the present invention has the following beneficial effects:

[0059] Through the mechanism from control parameter correction to modulation wave generation, the adaptability of the energy storage system to different working conditions is improved, the conversion efficiency of electric energy is optimized, and unnecessary energy loss is reduced.

[0060] By generating a set of evaluation values ​​based on the historical and current operating status data of each component of the energy storage system and setting a variety of control strategies accordingly, this dynamic control strategy adjustment based on component status can fully consider the performance changes of different components under different environmental and load conditions.

[0061] The valve base control protection unit can ensure that the SOC of the batteries connected to each power unit remains consistent through SOC balancing control, avoiding overcharging or over-discharging of the batteries; effective SOC balancing helps to improve the overall performance of the battery pack, extend the battery life, and increase the available capacity of the energy storage system.

[0062] The multi-level fault isolation mechanism can quickly isolate the faulty part when a fault occurs at any point in the battery pack, prevent the spread of the fault, and protect the safety of the entire energy storage system.

[0063] The sub-control protection unit obtains the relevant status evaluation value data set of the devices on the PCS unit, compares it with the historically set thresholds, and generates maintenance instructions, which can promptly discover potential problems of the devices in the PCS unit.

[0064] The air-cooled battery thermal management strategy ensures that the battery operates within an appropriate temperature range by monitoring the temperature of the battery cells and battery compartment in real time and performing corresponding temperature control.

[0065] The battery active safety strategy determines the working status and generates early warning instructions based on the real-time temperature data of the battery module. It can take measures before abnormal conditions occur in the battery (such as excessive temperature that may cause thermal runaway), effectively protect the battery, and prevent safety accidents caused by battery failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a structural diagram of a multi-level networked energy storage control and protection system provided by an embodiment of the present invention;

[0067] Figure 2 It is a schematic diagram of PQ decoupling control;

[0068] Figure 3 It is a schematic diagram of the main control protection unit device;

[0069] Figure 4 This is a multi-layer protection structure diagram of the energy storage system;

[0070] Figure 5 This is a diagram of the battery multi-stage DC fast fuse protection structure;

[0071] Figure 6 This is the device diagram of the valve base control and protection unit;

[0072] Figure 7 It is a schematic diagram of inter-phase SOC balancing control;

[0073] Figure 8 It is a schematic diagram of intra-phase SOC balancing control;

[0074] Fig. 9 This is a schematic diagram of the air duct setting on the battery cell;

[0075] Fig.10 Schematic diagram of battery compartment-level air-cooled battery thermal management. DETAILED DESCRIPTION

[0076] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0077] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0078] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0079] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0080] Embodiment 1:

[0081] The embodiment of the present invention provides a multi-level networked energy storage control and protection system, such as Figure 1 As shown, including:

[0082] Battery management unit, energy management unit, main control protection unit, valve base control protection unit and submodule control unit;

[0083] Among them, the battery management unit is used to obtain the operating status data of the current energy storage system;

[0084] The energy management unit is used to obtain the operating status data of the energy storage system and generate a primary control instruction based on the operating status data of the energy storage system and system requirements;

[0085] The main control protection unit is used to convert the primary control instructions generated in the energy management unit into a modulation wave;

[0086] The valve base control protection unit is used to coordinate the work of each unit in the three-phase PCS commutation chain; it is also used to generate the secondary control instructions corresponding to each PCS unit;

[0087] The sub-control protection unit is used to generate a driving pulse signal of the power device in combination with the secondary control instruction and by using a modulation algorithm.

[0088] Embodiment 2:

[0089] The energy management unit is also used for:

[0090] Generate a historical operating status evaluation value based on the acquired historical operating status data of each component of the energy storage system;

[0091] Set up multiple control strategies based on historical data and historical operating status evaluation values;

[0092] Obtain the operating status data of each component of the energy storage system at the current sampling time node to generate an operating status evaluation value set P of each component of the energy storage system at the current sampling time node, where P = {P1, P2...Pi...Pn};

[0093] Wherein, Pi represents the operating status evaluation value of the i-th component in the current energy storage system;

[0094] Pi=H*(f1*Ti+f2+Vi);

[0095] Among them, H is the environmental impact coefficient, which is obtained through historical environmental data, f1 is the weight of the temperature evaluation value of the i-th component, Ti represents the temperature evaluation value of the i-th component, f2 is the load evaluation value of the i-th component, and Vi represents the load evaluation value of the i-th component;

[0096] Generate a control strategy based on the set P of operating status evaluation values ​​of each component of the energy storage system at the current sampling time node;

[0097] Generate primary control instructions based on the control strategy, including: control parameters of the current energy storage system, voltage control target and start / stop instructions of the subsequent DC / DC.

[0098] In this embodiment, the PCS monitoring system can be configured separately or integrated with the substation comprehensive automation background to monitor the operating status of each component of the energy storage system. Different control methods and control parameters are configured according to system conditions and requirements to enable the energy storage system to operate in different modes, including fixed active power, fixed reactive power, frequency modulation, voltage regulation, VF, VSG, etc., to achieve the predetermined control target, and can communicate information and operation commands with AGC / AVC and the upper control (or dispatching center) through the communication interface.

[0099] The energy management unit has the following features and advantages:

[0100] SOPHIC integrated software platform with independent intellectual property rights has better compatibility;

[0101] Mature experience in large-scale power grid dispatching and substation monitoring platform;

[0102] New energy comprehensive monitoring and intelligent operation and maintenance system based on cloud computing;

[0103] Self-developed real-time database, 2 million points, data processing capacity of 5 million events per second Energy storage system energy management (planning curve, AGC, AVC);

[0104] The energy management unit and the main control protection unit determine the operation mode according to the equipment application function objectives, including fixed active power, fixed reactive power, frequency regulation, voltage regulation, VF operation, VSG operation, etc. The energy storage system operates in four quadrants and can adjust active and reactive power at the same time. Therefore, PQ decoupling control is adopted to realize independent exchange of active and reactive power with the power grid. Figure 2 shown.

[0105] The functions of each control strategy are as follows:

[0106] PQ mode: according to active and reactive power instructions, fast and accurate power output (grid-connected operation)

[0107] Frequency and voltage regulation mode: adjust active and reactive power according to frequency and voltage instructions (grid-connected operation)

[0108] VF mode: operate according to VF open loop or droop characteristics (off-grid operation)

[0109] VSG mode: PCS grid-connected energy storage characteristic operation (grid-connected / off-grid)

[0110] Embodiment 3:

[0111] The main control protection unit is as follows Figure 3 As shown, it is also used for:

[0112] Based on the primary control instruction, the modulation wave used for controlling each front-stage H-bridge in the current energy storage system is calculated to generate a three-phase modulation wave data set of the front-stage H-bridge;

[0113] The three-phase modulation wave data set of the front-stage H-bridge, the voltage control target and start / stop instructions of the rear-stage DC / DC are sent to the valve base control and protection unit, and the system active safety strategy is executed at the same time;

[0114] The system active safety strategy includes:

[0115] Set up multi-level fault isolation points based on battery module-battery column-battery cluster-battery stack-PCS;

[0116] The fault isolation point is a multi-stage DC fast-fuse protection device.

[0117] In this embodiment, the main control protection unit mainly completes the sampling of system voltage and current, and receives information such as battery state of charge (SOC) and battery health status (SOH). Combined with the realization goals of the control system, such as active power and reactive power control on the AC side, SOC balance control and other requirements, it completes the calculation of the modulation wave used for each front-stage H-bridge control, and sends the three-phase modulation wave of the front-stage H-bridge, the voltage control target of the rear-stage DC / DC and the start-stop command to the valve base control protection unit. The main control protection unit main control protection system can realize system-level control protection strategies such as system active safety strategies.

[0118] The system's active safety strategy is described as follows:

[0119] Multiple no-dead-zone protection designs fully protect the energy storage system and ensure that the battery can be safely isolated in the event of a short circuit fault at any point. Figure 4 shown.

[0120] Battery module - battery string - battery cluster - battery stack - PCS multi-level DC fast fuse protection ensures that any fault at any point in the battery pack can be effectively isolated to ensure the safe and reliable operation of the equipment, such as Figure 5 shown.

[0121] The millisecond-level communication delay between PCS and the battery management unit enables rapid battery protection, prevents overcharging and over-discharging, and effectively extends battery life.

[0122] Embodiment 4:

[0123] The valve base control and protection unit is also used for:

[0124] Receive the three-phase modulation wave sent by the main control protection unit, and generate the SOC balancing control strategy between the batteries connected to each power unit inside the valve base control protection unit based on the three-phase modulation wave;

[0125] Generating secondary control instructions based on SOC balancing control strategy includes: each H-bridge carrier, modulation wave or switching command;

[0126] And send the secondary control instructions to the sub-control protection unit.

[0127] In this embodiment, the valve base control and protection unit is the brain and control core of the entire converter valve. The direct-mounted energy storage system adopts a flexible DC transmission control architecture and has sufficient experience in how to control the coordination of many sub-units and ensure long-term stable and reliable operation under low power, high power and fault conditions. Figure 6 shown.

[0128] Since there are many power units in the cascade of PCS converters, the amount of trigger signals sent down and the amount of monitoring data received is large, so the integrity of all data must be guaranteed. The valve base control and protection unit adopted by NARI relay protection is based on phase-divided time-divided multi-channel high-speed parallel bus technology, which can realize high-precision, multi-channel, and real-time valve base control and protection. The valve base control and protection unit of the highly integrated valve control device adopts a high-performance general-purpose hardware platform with strong real-time processing capabilities. The DSP board adopts a high-performance 32-bit dual-core processor + DSP + dual FPGA hardware structure. Multiple processors and FPGAs work in parallel. The 32-bit dual-core processor is responsible for human-machine interface, communication, printing and other functions. The DSP is responsible for protection strategy calculation and export logic. Two large-capacity FPGAs are responsible for high-speed processing of real-time information of sub-modules. These high-performance hardware ensures that the device processes all sub-modules in real time at each sampling interval, realizing data phase-divided time-divided multi-channel high-speed parallel processing. The optical interface board can exchange sub-control and protection unit commands and information with the DSP board through the internal high-speed bus, and can be flexibly expanded. It has the characteristics of generality, flexibility, and easy maintenance. At the same time, a highly compact valve base control and protection unit design is adopted to complete the functions of the entire device in a 6U chassis, which increases the reliability of the system and saves space.

[0129] The highly integrated valve-based control and protection device based on phase-split, time-sharing, multi-channel, high-speed parallel bus technology can realize the integrated control of each sub-module, support redundant hot-swap maintenance, meet the control requirements of up to 224 sub-modules, and can be flexibly applied to direct-mounted energy storage systems of different voltages and different capacity levels.

[0130] The valve control device of the valve base control and protection unit receives the three-phase modulation wave sent by the main control and protection unit, and completes the SOC balancing control between the batteries connected to each power unit inside the valve base control and protection unit, thereby obtaining each H-bridge carrier and modulation wave or switching command, and sending it to the sub-control and protection unit. At the same time, the valve base control and protection unit sends the H-bridge related monitoring information to the main control and protection unit. At the same time, the valve base control and protection unit sends the battery SOC / SOH and other related information monitored by the BCMU to the main control and protection unit, which can realize complex control algorithms such as active energy balancing technology between phases and within phases.

[0131] Embodiment 5:

[0132] When generating the SOC balancing control strategy between the batteries connected to each power unit, it also includes:

[0133] Two-layer balancing control: the first layer is the inter-phase SOC balancing control strategy; the second layer is the intra-phase SOC balancing control strategy;

[0134] The first layer is the current control algorithm, which combines the command current, decoupling feedforward and PI control to control the centralized VSG output current to track the current command;

[0135] Combine inter-phase SOC balancing control and zero-sequence voltage injection or negative-sequence current injection to control the inter-phase SOC balancing of the ABC three-phase battery;

[0136] The second layer generates modulation waves for each module of the three phases through a single-stage frequency-doubled carrier phase-shifted SPWM modulation algorithm;

[0137] In this embodiment, the intra-phase SOC balancing of the batteries of the ABC three phases is controlled in combination with the intra-phase SOC balancing.

[0138] The algorithm block diagram of the phase-to-phase active balancing control strategy is shown in the figure below, which includes two layers of balancing control: the first layer is the phase-to-phase SOC balancing control. Figure 7 ; The second layer is the intra-phase SOC balance control such as Figure 8 To ensure the consistency of the SOC of the energy storage batteries in each module. The modulation algorithm adopts the SPWM algorithm based on single-stage frequency-multiplied carrier phase shift to increase the equivalent switching frequency and reduce high-frequency harmonic components.

[0139] The algorithm is divided into two layers:

[0140] The first layer is a conventional current control algorithm. According to the command current, decoupling feedforward and PI control are used to control the centralized VSG output current to track the current command. The algorithm output is a three-phase modulation wave. It should be noted that interphase SOC balancing control is added to this layer of the algorithm to achieve SOC balancing of the ABC three-phase battery. Interphase SOC balancing control can be achieved by zero-sequence voltage injection or negative-sequence current injection. Zero-sequence voltage injection is used here.

[0141] The second layer is a conventional single-stage frequency-doubled carrier phase-shifted SPWM (CPS-SPWM) modulation algorithm, which generates modulation waves for each module of the three phases. In this layer of the algorithm, intra-phase SOC balancing control is added, and the control implementation idea is similar to the SVG intra-phase voltage balancing control algorithm.

[0142] Embodiment 6:

[0143] The sub-control protection unit is also used for:

[0144] A corresponding sub-control protection unit is set in each PCS unit, and a driving pulse signal of the power device is generated based on the secondary control instruction and sent to the corresponding driving circuit. At the same time, a maintenance instruction of the PCS unit is generated based on the sub-control protection unit.

[0145] Embodiment 7:

[0146] The generation of the maintenance instruction of the PCS unit based on the sub-control protection unit includes:

[0147] Based on the sub-control protection unit, obtain the relevant status evaluation value data set A of the device on the current PCS unit, A={A1,A2…Ai…An};

[0148] Wherein, Ai represents the relevant status evaluation value of the i-th device on the current PCS unit, and n represents the number of devices on the current PCS unit;

[0149] Setting a status evaluation value threshold for each device based on historical data, comparing the status evaluation value of the device on the current PCS unit with the corresponding threshold, and generating a status evaluation information table for the current PCS unit;

[0150] Generate maintenance instructions for the PCS unit based on the relevant status evaluation information table of the current PCS unit.

[0151] As the control core of the unit, the sub-control protection unit needs to receive the control commands sent by the valve base control protection unit through optical fiber, mainly including: control of power devices and control of bypass switches. It decodes the received control instructions and sends them to the corresponding drive circuit. The trigger structure is shown in the figure below.

[0152] A PCS unit consists of multiple fully controlled devices, drive protection modules, power supply modules, resistors, capacitors and other electronic devices. In order to control and monitor the electronic devices of the valve unit, a sub-control protection unit needs to be installed on-site on each unit.

[0153] The sub-control protection unit also collects the relevant status of the unit's last device, and encodes it and sends it to the valve base control protection unit to monitor whether the unit is working properly. Such as: switch status (closed, refused to close, etc.), device status (overvoltage, overcurrent, dI / dt is too large, etc.), capacitor voltage. In addition, the sub-control protection unit is also responsible for receiving the power-on and power-off instructions sent by the valve base control protection unit to the battery management system battery management unit, and sending the battery SOC / SOH and other related information collected by the battery management unit to the valve base control protection unit.

[0154] Embodiment 8:

[0155] The battery management unit is also used for:

[0156] Control the opening and closing of internal circuit breakers and contactors based on the drive pulse signal, and simultaneously obtain the status monitoring data of each battery in each battery cluster and the battery's SOC / SOH information and upload them to the energy management unit;

[0157] Execute air-cooled battery thermal management strategy and battery active safety strategy.

[0158] Embodiment 9:

[0159] The execution of the air-cooled battery thermal management strategy and the battery active safety strategy includes:

[0160] The thermal management strategy of air-cooled batteries is as follows:

[0161] Monitor the temperature of each battery cell in the battery module in real time, and set up air ducts at each battery cell. Fig. 9 As shown, the temperature of each battery cell of the currently monitored battery module is controlled within a preset value range by controlling the on-off of the air duct;

[0162] Real-time monitoring of the battery compartment temperature and air-cooling to control the temperature of the battery compartment. Fig.10 ;

[0163] The battery active safety strategy is as follows:

[0164] The working status of the current battery module is judged based on the real-time temperature data of the current battery module, and an early warning instruction is generated based on the working status of the current battery module.

[0165] In this embodiment, the battery management unit communicates and receives the start / stop command forwarded by the sub-control protection unit to complete the opening and closing of the internal circuit breaker and contactor, and at the same time monitors the status of each battery in each battery cluster, collects SOC / SOH information and sends it to the sub-control protection unit. The battery management unit communication management system has an air-cooled battery thermal management strategy and a battery active safety strategy.

[0166] The thermal management strategy of air-cooled batteries is as follows:

[0167] Battery module level: full temperature monitoring and patented air duct design to control the temperature difference of different battery cells: 0.5C battery is controlled within 3°C; 1.0C battery is controlled within 5°C to ensure the consistency of the battery cells after long-term operation.

[0168] Battery compartment level: Air conditioning forced air cooling, system temperature controlled at 23±5℃, ensuring that the battery cells are always in the long-life temperature range.

[0169] Battery management unit communication can also implement active battery safety strategies, using early warning, alarm, and protection information as basic criteria, combining the absolute value and mutation of physical quantities such as temperature to form a composite criterion. It can judge thermal runaway based on unexpected temperature rise, and can also predict some complex trends through big data analysis of temperature and battery internal resistance.

[0170] The air-cooled battery thermal management strategy and battery active safety strategy implemented by the battery management unit are crucial to the safe operation of the battery. The air-cooled battery thermal management strategy monitors the temperature of the battery cell and battery compartment in real time and performs corresponding temperature control to ensure that the battery operates within an appropriate temperature range.

[0171] The battery active safety strategy determines the working status and generates early warning instructions based on the real-time temperature data of the battery module. It can take measures before abnormal conditions occur in the battery (such as excessive temperature that may cause thermal runaway), effectively protect the battery, and prevent safety accidents caused by battery failure.

[0172] The PCS unit charges and discharges the battery by receiving control instructions from the application layer, and uploads various alarm information from the battery management unit to the monitoring background to ensure safe, stable and efficient operation of the battery.

[0173] The sub-control protection unit communicates with the battery management unit, dynamically adjusts the charging and discharging parameters and performs corresponding actions based on the data provided by the battery management system, and realizes closed-loop control of the charging and discharging voltage and current to meet the various performance indicators of the battery in each charging and discharging stage.

[0174] The overall control architecture design ensures the rapid and effective flow of internal control information in the grid-connected energy storage.

[0175] Embodiment 10:

[0176] When uploading to the energy management unit, it includes:

[0177] Obtain battery status monitoring data and battery SOC / SOH information based on the battery management unit and upload them to the sub-control protection unit;

[0178] The sub-control protection unit obtains the H-bridge monitoring information and receives the battery status monitoring data and the battery SOC / SOH information and sends it to the valve base control protection unit;

[0179] The valve base control and protection unit sends the H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information to the main control and protection unit;

[0180] The H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information are sent to the energy management unit through the main control protection unit.

[0181] Finally, it should be noted that it is obvious that those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalent technology, the present invention is also intended to include these modifications and variations.

[0182] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A multi-level networked energy storage control and protection system, characterized in that: include: Battery management unit, energy management unit, main control protection unit, valve base control protection unit and submodule control unit; Among them, the battery management unit is used to obtain the operating status data of the current energy storage system; The energy management unit is used to obtain the operating status data of the energy storage system and generate a primary control instruction based on the operating status data of the energy storage system and system requirements; The main control protection unit is used to convert the primary control instructions generated in the energy management unit into a modulation wave; The valve base control protection unit is used to coordinate the work of each unit in the three-phase PCS commutation chain; it is also used to generate the secondary control instructions corresponding to each PCS unit; The sub-control protection unit is used to generate a driving pulse signal of the power device in combination with the secondary control instruction and by using a modulation algorithm.

2. The multi-level networked energy storage control and protection system according to claim 1, characterized in that: The energy management unit is also used for: Generate a historical operating status evaluation value based on the acquired historical operating status data of each component of the energy storage system; Set up multiple control strategies based on historical data and historical operating status evaluation values; Obtain the operating status data of each component of the energy storage system at the current sampling time node to generate an operating status evaluation value set P of each component of the energy storage system at the current sampling time node, where P = {P1, P2...Pi...Pn}; Wherein, Pi represents the operating status evaluation value of the i-th component in the current energy storage system; Pi=H*(f1*Ti+f2+Vi); Among them, H is the environmental impact coefficient, which is obtained through historical environmental data, f1 is the weight of the temperature evaluation value of the i-th component, Ti represents the temperature evaluation value of the i-th component, f2 is the load evaluation value of the i-th component, and Vi represents the load evaluation value of the i-th component; Generate a control strategy based on the set P of operating status evaluation values ​​of each component of the energy storage system at the current sampling time node; Generate primary control instructions based on the control strategy, including: control parameters of the current energy storage system, voltage control target and start / stop instructions of the subsequent DC / DC.

3. The multi-level networked energy storage control and protection system according to claim 2, characterized in that: The main control protection unit is also used for: Based on the primary control instruction, the modulation wave used for controlling each front-stage H-bridge in the current energy storage system is calculated to generate a three-phase modulation wave data set of the front-stage H-bridge; The three-phase modulation wave data set of the front-stage H-bridge, the voltage control target and start / stop instructions of the rear-stage DC / DC are sent to the valve base control and protection unit, and the system active safety strategy is executed at the same time; The system active safety strategy includes: Set up multi-level fault isolation points based on battery module-battery column-battery cluster-battery stack-PCS; The fault isolation point is a multi-stage DC fast-fuse protection device.

4. The multi-level networked energy storage control and protection system according to claim 3, characterized in that: The valve base control and protection unit is also used for: Receive the three-phase modulation wave sent by the main control protection unit, and generate the SOC balancing control strategy between the batteries connected to each power unit inside the valve base control protection unit based on the three-phase modulation wave; Generating secondary control instructions based on SOC balancing control strategy includes: each H-bridge carrier, modulation wave or switching command; And send the secondary control instructions to the sub-control protection unit.

5. The multi-level networked energy storage control and protection system according to claim 4, characterized in that: When generating the SOC balancing control strategy between the batteries connected to each power unit, it also includes: Two-layer balancing control: the first layer is the inter-phase SOC balancing control strategy; the second layer is the intra-phase SOC balancing control strategy; The first layer is the current control algorithm, which combines the command current, decoupling feedforward and PI control to control the centralized VSG output current to track the current command; Combine inter-phase SOC balancing control and zero-sequence voltage injection or negative-sequence current injection to control the inter-phase SOC balancing of the ABC three-phase battery; The second layer generates modulation waves for each module of the three phases through a single-stage frequency-doubled carrier phase-shifted SPWM modulation algorithm; Combined with the intra-phase SOC balancing control, the intra-phase SOC balancing of the ABC three-phase battery is achieved.

6. The multi-level networked energy storage control and protection system according to claim 5, characterized in that: The sub-control protection unit is also used for: A corresponding sub-control protection unit is set in each PCS unit, and a driving pulse signal of the power device is generated based on the secondary control instruction and sent to the corresponding driving circuit. At the same time, a maintenance instruction of the PCS unit is generated based on the sub-control protection unit.

7. The multi-level networked energy storage control and protection system according to claim 6, characterized in that: The generation of the maintenance instruction of the PCS unit based on the sub-control protection unit includes: Based on the sub-control protection unit, obtain the relevant status evaluation value data set A of the device on the current PCS unit, A={A1,A2…Ai…An}; Wherein, Ai represents the relevant status evaluation value of the i-th device on the current PCS unit, and n represents the number of devices on the current PCS unit; Setting a status evaluation value threshold for each device based on historical data, comparing the status evaluation value of the device on the current PCS unit with the corresponding threshold, and generating a status evaluation information table for the current PCS unit; Generate maintenance instructions for the PCS unit based on the relevant status evaluation information table of the current PCS unit.

8. The multi-level networked energy storage control and protection system according to claim 7, characterized in that: The battery management unit is also used for: Control the opening and closing of internal circuit breakers and contactors based on the drive pulse signal, and simultaneously obtain the status monitoring data of each battery in each battery cluster and the battery's SOC / SOH information and upload them to the energy management unit; Execute air-cooled battery thermal management strategy and battery active safety strategy.

9. The multi-level networked energy storage control and protection system according to claim 8, characterized in that: The execution of the air-cooled battery thermal management strategy and the battery active safety strategy includes: The thermal management strategy of air-cooled batteries is as follows: Monitor the temperature of each battery cell of the battery module in real time, and set an air duct at each battery cell to control the temperature of each battery cell of the currently monitored battery module within the preset value range by controlling the on and off of the air duct; Real-time monitoring of the temperature of the battery compartment and control of the temperature of the battery compartment through air cooling; The battery active safety strategy is as follows: The working status of the current battery module is judged based on the real-time temperature data of the current battery module, and an early warning instruction is generated based on the working status of the current battery module.

10. The multi-level networked energy storage control and protection system according to claim 9, characterized in that: When uploading to the energy management unit, it includes: Obtain battery status monitoring data and battery SOC / SOH information based on the battery management unit and upload them to the sub-control protection unit; The sub-control protection unit obtains the H-bridge monitoring information and receives the battery status monitoring data and the battery SOC / SOH information and sends it to the valve base control protection unit; The valve base control and protection unit sends the H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information to the main control and protection unit; The H-bridge related monitoring information, battery status monitoring data and battery SOC / SOH information are sent to the energy management unit through the main control protection unit.

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