CN114006391B - Medium-voltage direct-hanging energy storage converter system and start-stop control method thereof - Google Patents
Medium-voltage direct-hanging energy storage converter system and start-stop control method thereof Download PDFInfo
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- CN114006391B CN114006391B CN202111279538.7A CN202111279538A CN114006391B CN 114006391 B CN114006391 B CN 114006391B CN 202111279538 A CN202111279538 A CN 202111279538A CN 114006391 B CN114006391 B CN 114006391B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
Abstract
The application discloses a medium-voltage direct-hanging energy storage converter system and a start-stop control method thereof, comprising the following steps: the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, each phase is formed by connecting double H-bridge power modules in series, and the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel. The high-frequency bus structure is adopted, the modules of the high-voltage alternating-current device and the low-voltage direct-current device are different from each other, the flexibility is high, and compared with a chain structure, the number of devices of the converter and the electric energy conversion links are saved, the cost is reduced, and the conversion efficiency is improved. The high-voltage power grid can be directly hung without a power frequency transformer, and the requirement of quick power response can be met.
Description
Technical Field
The application relates to the technical field, in particular to a medium-voltage direct-hanging energy storage converter system and a start-stop control method thereof.
Background
The energy storage converter device is an important component of the energy storage system and plays roles of alternating current and direct current conversion and power bidirectional transmission between the battery and the alternating current power grid.
The current energy storage device mainly has the following two structures: firstly), an energy storage device is connected into a power grid through a power frequency transformer, and the structure has a series of problems of low efficiency, large volume, high cost and the like; two) energy storage devices of chain and MMC structures, wherein MMC structures have certain disadvantages in terms of complexity, cost, etc. compared to chain structures. The chain type structure energy storage device adopts a chain type H bridge to directly hang a battery pack or the chain type H bridge is connected with the battery pack through a DC/DC converter, and has the advantages of simple structure, more devices and more electric energy conversion links of the converter, difficult efficiency improvement and higher cost; meanwhile, since the charge and discharge power of the battery cannot be effectively controlled, the life of the battery is reduced.
The energy storage device has a plurality of switches and modules, and each device is complicated in start and stop control and has a certain logic sequence, so that misoperation can bring more potential safety hazards, and the stable operation of the energy storage system is not facilitated.
Disclosure of Invention
In order to solve the technical problems, the application provides the following technical scheme:
in a first aspect, embodiments of the present application provide a medium voltage direct hanging energy storage converter system, including: the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, each phase is formed by connecting double H-bridge power modules in series, and the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel.
By adopting the implementation mode, the common high-frequency bus structure is adopted, the modules of the high-voltage alternating-current device and the low-voltage direct-current device are different from each other, the flexibility is high, compared with a chain structure, the number of devices and the electric energy conversion links of the converter are saved, the cost is reduced, and the conversion efficiency is improved. The high-voltage power grid can be directly hung without a power frequency transformer, and the requirement of quick power response can be met.
With reference to the first aspect, in a first possible implementation manner of the first aspect, the dual H-bridge power module includes a low-frequency H-bridge, a first dc capacitor, and a first high-frequency H-bridge, where the low-frequency H-bridge, the first dc capacitor, and the first high-frequency H-bridge are connected in parallel, an input end of the low-frequency H-bridge is electrically connected to an ac power grid, an output end of the first high-frequency H-bridge is electrically connected to an input end of a first high-frequency transformer, and an output end of the first high-frequency transformer is electrically connected to the single H-bridge power module.
With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the single H-bridge power module includes a second high-frequency H-bridge and a second dc capacitor, the second high-frequency H-bridge and the second dc capacitor are connected in parallel, an input end of the second high-frequency H-bridge is electrically connected to an output end of a second high-frequency transformer, and an input end of the second high-frequency transformer is electrically connected to an output end of the first high-frequency transformer.
With reference to the first aspect or the first or second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, an outgoing circuit breaker is disposed between the low-frequency H-bridge and the ac power grid, a first end of the outgoing circuit breaker is electrically connected with the ac power grid, a second end of the outgoing circuit breaker is electrically connected with a first end of a first contactor, a second end of the first contactor is electrically connected with a first end of a first inductor, a second end of the first inductor is electrically connected with the low-frequency H-bridge, and the first contactor is connected with a first bypass soft start resistor in parallel.
With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, a first dc breaker and a second dc breaker are disposed between the low-voltage dc device and the energy storage end, a first end of the first dc breaker is electrically connected with the positive electrode of the energy storage end, a second end of the first dc breaker is electrically connected with a first end of a second contactor, a second end of the second contactor is electrically connected with a first end of a second inductor, a second end of the second inductor is electrically connected with the first phase single H-bridge power module, and the second contactor is connected with a second bypass soft start resistor in parallel; the first end of the second direct current breaker is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker is electrically connected with the first end of the third contactor, the second end of the third contactor is electrically connected with the first end of the third inductor, the second end of the third inductor is electrically connected with the third single H-bridge power module, and the third contactor is connected with the third bypass soft start resistor in parallel.
With reference to the first aspect or the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the energy storage end is an energy storage battery pack.
In a second aspect, an embodiment of the present application provides a control method for a medium voltage direct-hanging energy storage converter system, where an operation condition is grid-connected operation start, and the method is used for controlling the medium voltage direct-hanging energy storage converter system according to the first aspect or any implementation manner of the first aspect, and the method includes:
the control mode of the high-voltage alternating-current device is selected as a power following control mode, and the control is used for realizing that the active power exchanged between the high-voltage alternating-current device and the alternating-current power grid automatically follows the charging or discharging power of the low-voltage direct-current device, and the reactive power exchanged between the high-voltage alternating-current device and the alternating-current power grid automatically follows the reactive power constant value issued by the upper-level dispatching;
selecting a control mode of the low-voltage direct-current device as a constant power control mode, and realizing that the active power exchanged between the low-voltage direct-current device and the energy storage battery automatically follows an active power constant value issued by the upper-level scheduling through the control;
closing an outgoing line breaker to charge a first direct-current capacitor of the high-voltage alternating-current device, locking a first contactor and a first bypass soft start resistor, unlocking a low-frequency H bridge to control the average value of the first direct-current capacitor voltages of all the high-voltage alternating-current devices to be a set reference value, and unlocking a first high-frequency H bridge to supply power to a high-frequency bus;
the second high-frequency H bridge of the low-voltage direct-current device is locked, and the high-voltage alternating-current device charges a second direct-current capacitor of the low-voltage direct-current device through a high-frequency bus;
when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the battery pack is smaller than a set value, the low-voltage direct-current device controller closes a direct-current breaker of the port, and the energy storage battery pack is connected to the low-voltage direct-current device;
the low-voltage direct-current device controller unlocks the second high-frequency H bridges of all the modules of the port, and a constant-power mode is put into operation;
after the low-voltage direct-current device is started, information is sent to the high-voltage alternating-current device, and the high-voltage alternating-current device is responsible for receiving the fixed values of active power and reactive power issued by the upper-level dispatching and coordinating the overall operation of the two ports.
In a third aspect, an embodiment of the present application provides a control method for a medium voltage direct-hanging energy storage converter system, where an operation condition is a grid-connected operation shutdown, and the method is used for controlling the medium voltage direct-hanging energy storage converter system according to the first aspect or any implementation manner of the first aspect, and the method includes:
immediately and synchronously controlling the power of the high-voltage alternating current device and the low-voltage direct current device to be reduced to zero according to a preset slope after the low-voltage direct current device controller receives a shutdown instruction;
after the power of the high-voltage alternating-current device and the low-voltage direct-current device is reduced to zero, the high-frequency H bridge of the high-voltage alternating-current device and the high-frequency H bridge of the low-voltage direct-current device are coordinated by the high-voltage alternating-current device controller to be locked at the same time, and the high-frequency bus is in power failure;
after the high-frequency H bridge of the high-voltage alternating current device and the high-frequency H bridge of the low-voltage direct current device are locked, the direct current breaker of the low-voltage direct current device is tripped, the energy storage battery pack is withdrawn from operation, and the low-voltage direct current device is stopped;
after the low-voltage direct current device is stopped, the low-frequency H bridge of the high-voltage alternating current device is locked, the grid-connected switch of the high-voltage alternating current device is tripped, and the whole machine is stopped.
In a fourth aspect, an embodiment of the present application provides a control method for a medium voltage direct-hanging energy storage converter system, where an operation condition is off-grid operation start, and the method is used for controlling the medium voltage direct-hanging energy storage converter system according to the first aspect or any implementation manner of the first aspect, and the method includes:
selecting a low-frequency H-bridge control mode of the high-voltage alternating current device as a V/F control mode, and selecting a high-frequency H-bridge control mode as a direct-current voltage control mode;
selecting a control mode of the low-voltage direct current device as a following control mode, and realizing that active power exchanged between the low-voltage direct current device and the energy storage battery automatically follows active power output by the high-voltage alternating current device through the control;
closing a direct current breaker of the low-voltage direct current device, and charging a second direct current capacitor of the low-voltage direct current device by an energy storage battery pack through a soft start resistor, wherein a second high-frequency H bridge of the low-voltage direct current device is locked at the stage;
when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the energy storage battery pack is smaller than a set value, the low-voltage direct-current device controller closes a soft start resistor bypass breaker of the port, and the energy storage battery pack is connected to the low-voltage direct-current device;
the low-voltage direct-current device controller unlocks the second high-frequency H bridges of all the modules of the low-voltage direct-current device and charges the first direct-current capacitor of the high-voltage alternating-current device module through the high-frequency bus;
after the high-voltage alternating-current device is charged, unlocking a first high-frequency H bridge of the high-voltage alternating-current device, starting constant-voltage control of the first high-frequency H bridge of the high-voltage alternating-current device, and performing closed-loop control on the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device module;
after the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device is stabilized near the reference value, unlocking the low-frequency H bridge of the high-voltage alternating-current device, and putting the high-voltage alternating-current device into operation in a V/F control mode of the low-frequency H bridge;
after the whole energy storage converter is started, the high-voltage alternating-current device is responsible for receiving the voltage and frequency fixed values issued by the upper-level dispatching and coordinating the whole operation of the high-voltage alternating-current device and the low-voltage direct-current device.
In a fifth aspect, an embodiment of the present application provides a control method for a medium voltage direct-hanging energy storage converter system, where an operation condition is off-grid operation shutdown, and the method is used for controlling the medium voltage direct-hanging energy storage converter system according to the first aspect or any implementation manner of the first aspect, and the method includes:
after receiving the shutdown instruction, the high-voltage alternating-current device controller disconnects the outgoing circuit breaker of the high-voltage alternating-current device and cuts off the external load of the energy storage converter;
after the outgoing line breaker of the high-voltage alternating current device reaches the separated position, the high-voltage alternating current device controller coordinates the high-frequency H bridge of the high-voltage alternating current device and the low-voltage direct current device to be synchronously locked, and the high-frequency bus is in power failure;
after the high-frequency H bridge of the high-voltage alternating current device and the high-frequency H bridge of the low-voltage direct current device are locked, the direct current breaker of the low-voltage direct current device is disconnected, the energy storage battery pack is withdrawn from operation, and the low-voltage direct current device is stopped;
after the low-voltage direct-current device is stopped, the low-frequency H bridge of the high-voltage alternating-current device is locked, and the whole energy storage converter is stopped.
Drawings
Fig. 1 is a schematic structural diagram of a medium-voltage direct-hanging energy storage converter system according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a dual H-bridge power module according to an embodiment of the present application;
fig. 3 is a schematic diagram of a single H-bridge power module according to an embodiment of the present application;
fig. 4 is a schematic flow chart of a control method of a medium-voltage direct-hanging energy storage converter system according to an embodiment of the present application;
fig. 5 is a schematic flow chart of a control method of a medium-voltage direct-hanging energy storage converter system according to an embodiment of the present application;
fig. 6 is a schematic flow chart of a control method of a medium-voltage direct-hanging energy storage converter system according to an embodiment of the present application;
fig. 7 is a schematic flow chart of a control method of a medium-voltage direct-hanging energy storage converter system according to an embodiment of the present application;
in fig. 1-7, the symbols are represented as:
h1-low frequency H bridge, H2-first high frequency H bridge, H3-second high frequency H bridge, C1-first direct current capacitor, C2-second direct current capacitor, T1-first high frequency transformer, T2-second high frequency transformer, QS 11-outgoing circuit breaker, QS 12-first contactor, QS 21-first direct current circuit breaker, QS 22-second direct current circuit breaker, QS 23-second contactor, QS 24-third contactor, R1-first bypass soft start resistor, R2-second bypass soft start resistor, R3-third bypass soft start resistor, L1-first inductor, L2-second inductor, L3-third inductor.
Detailed Description
The present invention is described below with reference to the drawings and the detailed description.
Embodiment one:
fig. 1 is a schematic structural diagram of a medium-voltage direct-hanging energy storage converter system provided in an embodiment of the present application, referring to fig. 1, the medium-voltage direct-hanging energy storage converter system in this embodiment includes: the high-voltage alternating current device is electrically connected with an alternating current power grid, and the low-voltage direct current device is electrically connected with an energy storage end, wherein the high-voltage alternating current device is electrically connected with the low-voltage direct current device through a high-frequency transformer, and the energy storage end is an energy storage battery pack. In this embodiment, the high-voltage ac device is a three-phase star-type connection mode, each phase is formed by connecting double H-bridge power modules in series, and the low-voltage dc device is formed by connecting single H-bridge power modules in parallel.
Referring to fig. 2, the dual H-bridge power module includes a low-frequency H-bridge H1, a first dc capacitor C1, and a first high-frequency H-bridge H2, where the low-frequency H-bridge H1, the first dc capacitor C1, and the first high-frequency H-bridge H2 are connected in parallel, an input end of the low-frequency H-bridge H1 is electrically connected to an ac power grid, an output end of the first high-frequency H-bridge H2 is electrically connected to an input end of a first high-frequency transformer T1, and an output end of the first high-frequency transformer T1 is electrically connected to the single H-bridge power module.
Referring to fig. 3, the single H-bridge power module includes a second high-frequency H-bridge H3 and a second dc capacitor C2, where the second high-frequency H-bridge H3 and the second dc capacitor C2 are connected in parallel, an input end of the second high-frequency H-bridge H3 is electrically connected to an output end of a second high-frequency transformer T2, and an input end of the second high-frequency transformer T2 is electrically connected to an output end of the first high-frequency transformer T1.
Referring further to fig. 1, an outgoing circuit breaker QS11 is disposed between the low-frequency H-bridge H1 and the ac power grid, a first end of the outgoing circuit breaker QS11 is electrically connected with the ac power grid, a second end of the outgoing circuit breaker QS11 is electrically connected with a first end of a first contactor QS12, a second end of the first contactor QS12 is electrically connected with a first end of a first inductor L1, a second end of the first inductor L1 is electrically connected with the low-frequency H-bridge H1, and the first contactor QS12 is connected with a first bypass soft start resistor R1 in parallel.
Be provided with first direct current breaker QS21 and second direct current breaker QS22 between low voltage DC device and the energy storage end, the first end and the positive pole electricity of energy storage end of first direct current breaker QS21 are connected, the second end of first direct current breaker QS21 is connected with the first end electricity of second contactor QS23, the second end and the first end electricity of second inductance L2 of second contactor QS23 are connected, the second end and the first looks single H bridge power module electricity of second inductance L2 are connected, second contactor QS23 parallel connection second bypass soft start resistance R2.
The first end of the second direct current breaker QS22 is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker QS22 is electrically connected with the first end of the third contactor QS24, the second end of the third contactor QS24 is electrically connected with the first end of the third inductor L3, the second end of the third inductor L3 is electrically connected with the third single H-bridge power module, and the third contactor QS24 is connected with the third bypass soft start resistor R3 in parallel.
Corresponding to the medium-voltage direct-hanging energy storage converter system provided by the embodiment, the application also provides an embodiment for controlling the start and stop of the medium-voltage direct-hanging energy storage converter system.
Embodiment two:
the embodiment provides a control method of a medium-voltage direct-hanging energy storage converter system, in particular to a grid-connected operation starting control method of the medium-voltage direct-hanging energy storage converter system. Referring to fig. 4, the method includes:
s101, selecting a control mode of the high-voltage alternating-current device as a power following control mode, and realizing that active power exchanged between the high-voltage alternating-current device and an alternating-current power grid automatically follows charging or discharging power of a low-voltage direct-current device through the control, wherein reactive power exchanged between the high-voltage alternating-current device and the alternating-current power grid automatically follows a reactive power fixed value issued by a superior dispatching.
S102, selecting a control mode of the low-voltage direct-current device as a constant power control mode, and realizing that the active power exchanged between the low-voltage direct-current device and the energy storage battery automatically follows an active power fixed value issued by the upper-level scheduling through the control.
And S103, closing an outgoing line breaker to charge a first direct-current capacitor of the high-voltage alternating-current device, locking a first contactor and a first bypass soft start resistor, unlocking the low-frequency H bridge to control the average value of the first direct-current capacitor voltages of all the high-voltage alternating-current devices to be a set reference value, and unlocking the first high-frequency H bridge to supply power to the high-frequency bus.
S104, locking a second high-frequency H bridge of the low-voltage direct-current device, and charging a second direct-current capacitor of the low-voltage direct-current device by the high-voltage alternating-current device through the high-frequency bus.
And S105, when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the battery pack is smaller than a set value, the low-voltage direct-current device controller closes the direct-current circuit breaker of the port, and the energy storage battery pack is connected into the low-voltage direct-current device.
S106, the low-voltage direct-current device controller unlocks the second high-frequency H bridges of all the modules of the port, and the constant-power mode is put into operation.
And S107, after the low-voltage direct-current device is started, sending information to the high-voltage alternating-current device, wherein the high-voltage alternating-current device is responsible for receiving the fixed values of the active power and the reactive power issued by the upper-level dispatching and coordinating the overall operation of the two ports.
Embodiment III:
the embodiment provides a control method of a medium-voltage direct-hanging energy storage converter system, in particular to a shutdown control method for grid-connected operation of the medium-voltage direct-hanging energy storage converter system. Referring to fig. 5, the method includes:
and S201, immediately and synchronously controlling the power of the high-voltage alternating current device and the low-voltage direct current device to be reduced to zero according to a preset slope after the low-voltage direct current device controller receives a shutdown instruction.
And S202, after the power of the high-voltage alternating-current device and the low-voltage direct-current device is reduced to zero, the high-frequency H bridge of the high-voltage alternating-current device and the high-frequency H bridge of the low-voltage direct-current device are coordinated by the high-voltage alternating-current device controller to be locked simultaneously, and the high-frequency bus is powered off.
And S203, after the high-frequency H bridge of the high-voltage alternating-current device and the high-frequency H bridge of the low-voltage direct-current device are locked, the direct-current circuit breaker of the low-voltage direct-current device is tripped, the energy storage battery pack is out of operation, and the low-voltage direct-current device is stopped.
S204, after the low-voltage direct-current device is stopped, locking the low-frequency H bridge of the high-voltage alternating-current device, tripping off the grid-connected switch of the high-voltage alternating-current device, and completing the whole machine stopping operation.
Embodiment four:
the embodiment provides a control method of a medium-voltage direct-hanging energy storage converter system, in particular to a start control method of off-grid operation of the medium-voltage direct-hanging energy storage converter system. Referring to fig. 6, the method includes:
s301, selecting a low-frequency H-bridge control mode of the high-voltage alternating-current device as a V/F control mode, and selecting a high-frequency H-bridge control mode as a direct-current voltage control mode.
S302, selecting a control mode of the low-voltage direct current device as a following control mode, and realizing that active power exchanged between the low-voltage direct current device and the energy storage battery automatically follows active power output by the high-voltage alternating current device through the control mode.
S303, closing a direct current breaker of the low-voltage direct current device, and charging a second direct current capacitor of the low-voltage direct current device by an energy storage battery pack through a soft start resistor, wherein a second high-frequency H bridge of the low-voltage direct current device is locked at the stage.
And S304, when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the energy storage battery pack is smaller than a set value, the low-voltage direct-current device controller closes the soft start resistor bypass breaker of the port, and the energy storage battery pack is connected to the low-voltage direct-current device.
S305, the low-voltage direct-current device controller unlocks the second high-frequency H bridges of all the modules of the low-voltage direct-current device, and charges the first direct-current capacitors of the high-voltage alternating-current device modules through the high-frequency bus.
And S306, unlocking the first high-frequency H bridge of the high-voltage alternating-current device after the high-voltage alternating-current device is charged, starting constant-voltage control of the first high-frequency H bridge of the high-voltage alternating-current device, and performing closed-loop control on the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device module.
S307, after the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device is stabilized near the reference value, unlocking the low-frequency H bridge of the high-voltage alternating-current device, and putting the high-voltage alternating-current device into operation in a V/F control mode of the low-frequency H bridge.
And S308, after the whole energy storage converter is started, the high-voltage alternating-current device is responsible for receiving the voltage and frequency fixed values issued by the upper-level dispatching and coordinating the integral operation of the high-voltage alternating-current device and the low-voltage direct-current device.
Fifth embodiment:
the embodiment provides a control method of a medium-voltage direct-hanging energy storage converter system, in particular to an off-grid operation shutdown control method of the medium-voltage direct-hanging energy storage converter system. Referring to fig. 7, the method includes:
s401, after receiving a shutdown instruction, the high-voltage alternating-current device controller turns off an outgoing circuit breaker of the high-voltage alternating-current device, and cuts off an external load of the energy storage converter.
And S402, after the outgoing line breaker of the high-voltage alternating-current device reaches the separated position, the high-voltage alternating-current device controller coordinates the high-frequency H bridge of the high-voltage alternating-current device and the low-voltage direct-current device to be synchronously locked, and the high-frequency bus is powered off.
S403, after the high-frequency H bridge of the high-voltage alternating-current device and the high-frequency H bridge of the low-voltage direct-current device are locked, the direct-current circuit breaker of the low-voltage direct-current device is disconnected, the energy storage battery pack is withdrawn from operation, and the low-voltage direct-current device is stopped.
S404, after the low-voltage direct-current device is stopped, the low-frequency H bridge of the high-voltage alternating-current device is locked, and the whole energy storage converter is stopped.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Claims (4)
1. The control method of the medium-voltage direct-hanging energy storage converter system is characterized by comprising the steps of controlling the medium-voltage direct-hanging energy storage converter system,
the medium-voltage direct-hanging energy storage converter system comprises:
the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, and each phase is formed by connecting double H-bridge power modules in series; the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel; the double-H-bridge power module comprises a low-frequency H-bridge, a first direct-current capacitor and a first high-frequency H-bridge, wherein the low-frequency H-bridge, the first direct-current capacitor and the first high-frequency H-bridge are connected in parallel; the input end of the low-frequency H bridge is electrically connected with an alternating current power grid, the output end of the first high-frequency H bridge is electrically connected with the input end of a first high-frequency transformer, and the output end of the first high-frequency transformer is electrically connected with the single H bridge power module; the single H-bridge power module comprises a second high-frequency H-bridge and a second direct-current capacitor; the second high-frequency H bridge is connected with the second direct-current capacitor in parallel, the input end of the second high-frequency H bridge is electrically connected with the output end of the second high-frequency transformer, and the input end of the second high-frequency transformer is electrically connected with the output end of the first high-frequency transformer; an outgoing line breaker is arranged between the low-frequency H bridge and the alternating current power grid, a first end of the outgoing line breaker is electrically connected with the alternating current power grid, a second end of the outgoing line breaker is electrically connected with a first end of a first contactor, a second end of the first contactor is electrically connected with a first end of a first inductor, a second end of the first inductor is electrically connected with the low-frequency H bridge, and the first contactor is connected with a first bypass soft start resistor in parallel; a first direct current breaker and a second direct current breaker are arranged between the low-voltage direct current device and the energy storage end, the first end of the first direct current breaker is electrically connected with the positive electrode of the energy storage end, the second end of the first direct current breaker is electrically connected with the first end of a second contactor, the second end of the second contactor is electrically connected with the first end of a second inductor, the second end of the second inductor is electrically connected with a first phase single H-bridge power module, and the second contactor is connected with a second bypass soft start resistor in parallel; the first end of the second direct current breaker is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker is electrically connected with the first end of the third contactor, the second end of the third contactor is electrically connected with the first end of the third inductor, the second end of the third inductor is electrically connected with the third single H-bridge power module, and the third contactor is connected with the third bypass soft start resistor in parallel; the energy storage end is an energy storage battery pack;
the method comprises the following steps:
the control mode of the high-voltage alternating-current device is selected as a power following control mode, and the control is used for realizing that the active power exchanged between the high-voltage alternating-current device and the alternating-current power grid automatically follows the charging or discharging power of the low-voltage direct-current device, and the reactive power exchanged between the high-voltage alternating-current device and the alternating-current power grid automatically follows the reactive power constant value issued by the upper-level dispatching; selecting a control mode of the low-voltage direct-current device as a constant power control mode, and realizing that the active power exchanged between the low-voltage direct-current device and the energy storage battery automatically follows an active power constant value issued by the upper-level scheduling through the control; closing an outgoing line breaker to charge a first direct-current capacitor of the high-voltage alternating-current device, locking a first contactor and a first bypass soft start resistor, unlocking a low-frequency H bridge to control the average value of the first direct-current capacitor voltages of all the high-voltage alternating-current devices to be a set reference value, and unlocking a first high-frequency H bridge to supply power to a high-frequency bus; the second high-frequency H bridge of the low-voltage direct-current device is locked, and the high-voltage alternating-current device charges a second direct-current capacitor of the low-voltage direct-current device through a high-frequency bus; when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the battery pack is smaller than a set value, the low-voltage direct-current device controller closes a first direct-current circuit breaker and a second direct-current circuit breaker of the low-voltage direct-current end, and the energy storage battery pack is connected to the low-voltage direct-current device; the low-voltage direct-current device controller unlocks all second high-frequency H bridges at the low-voltage direct-current end, and the constant-power mode is put into operation; after the low-voltage direct-current device is started, information is sent to the high-voltage alternating-current device, and the high-voltage alternating-current device is responsible for receiving the fixed values of active power and reactive power issued by the upper-level dispatching and coordinating the overall operation of the high-voltage alternating-current device and the low-voltage direct-current device.
2. The control method of the medium-voltage direct-hanging energy storage converter system is characterized by controlling the medium-voltage direct-hanging energy storage converter system,
the medium-voltage direct-hanging energy storage converter system comprises:
the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, and each phase is formed by connecting double H-bridge power modules in series; the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel; the double-H-bridge power module comprises a low-frequency H-bridge, a first direct-current capacitor and a first high-frequency H-bridge, wherein the low-frequency H-bridge, the first direct-current capacitor and the first high-frequency H-bridge are connected in parallel; the input end of the low-frequency H bridge is electrically connected with an alternating current power grid, the output end of the first high-frequency H bridge is electrically connected with the input end of a first high-frequency transformer, and the output end of the first high-frequency transformer is electrically connected with the single H bridge power module; the single H-bridge power module comprises a second high-frequency H-bridge and a second direct-current capacitor; the second high-frequency H bridge is connected with the second direct-current capacitor in parallel, the input end of the second high-frequency H bridge is electrically connected with the output end of the second high-frequency transformer, and the input end of the second high-frequency transformer is electrically connected with the output end of the first high-frequency transformer; an outgoing line breaker is arranged between the low-frequency H bridge and the alternating current power grid, a first end of the outgoing line breaker is electrically connected with the alternating current power grid, a second end of the outgoing line breaker is electrically connected with a first end of a first contactor, a second end of the first contactor is electrically connected with a first end of a first inductor, a second end of the first inductor is electrically connected with the low-frequency H bridge, and the first contactor is connected with a first bypass soft start resistor in parallel; a first direct current breaker and a second direct current breaker are arranged between the low-voltage direct current device and the energy storage end, the first end of the first direct current breaker is electrically connected with the positive electrode of the energy storage end, the second end of the first direct current breaker is electrically connected with the first end of a second contactor, the second end of the second contactor is electrically connected with the first end of a second inductor, the second end of the second inductor is electrically connected with a first phase single H-bridge power module, and the second contactor is connected with a second bypass soft start resistor in parallel; the first end of the second direct current breaker is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker is electrically connected with the first end of the third contactor, the second end of the third contactor is electrically connected with the first end of the third inductor, the second end of the third inductor is electrically connected with the third single H-bridge power module, and the third contactor is connected with the third bypass soft start resistor in parallel; the energy storage end is an energy storage battery pack;
the method comprises the following steps:
immediately and synchronously controlling the power of the high-voltage alternating current device and the low-voltage direct current device to be reduced to zero according to a preset slope after the low-voltage direct current device controller receives a shutdown instruction; after the power of the high-voltage alternating-current device and the low-voltage direct-current device is reduced to zero, the high-frequency H bridge of the high-voltage alternating-current device and the high-frequency H bridge of the low-voltage direct-current device are coordinated by the high-voltage alternating-current device controller to be locked at the same time, and the high-frequency bus is in power failure; after the high-frequency H bridge of the high-voltage alternating current device and the high-frequency H bridge of the low-voltage direct current device are locked, the first direct current breaker and the second direct current breaker of the low-voltage direct current device are tripped, the energy storage battery pack is out of operation, and the low-voltage direct current device is stopped; after the low-voltage direct current device is stopped, the low-frequency H bridge of the high-voltage alternating current device is locked, the grid-connected switch of the high-voltage alternating current device is tripped, and the whole energy storage conversion system is stopped.
3. The control method of the medium-voltage direct-hanging energy storage converter system is characterized by controlling the medium-voltage direct-hanging energy storage converter system,
the medium-voltage direct-hanging energy storage converter system comprises:
the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, and each phase is formed by connecting double H-bridge power modules in series; the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel; the double-H-bridge power module comprises a low-frequency H-bridge, a first direct-current capacitor and a first high-frequency H-bridge, wherein the low-frequency H-bridge, the first direct-current capacitor and the first high-frequency H-bridge are connected in parallel; the input end of the low-frequency H bridge is electrically connected with an alternating current power grid, the output end of the first high-frequency H bridge is electrically connected with the input end of a first high-frequency transformer, and the output end of the first high-frequency transformer is electrically connected with the single H bridge power module; the single H-bridge power module comprises a second high-frequency H-bridge and a second direct-current capacitor; the second high-frequency H bridge is connected with the second direct-current capacitor in parallel, the input end of the second high-frequency H bridge is electrically connected with the output end of the second high-frequency transformer, and the input end of the second high-frequency transformer is electrically connected with the output end of the first high-frequency transformer; an outgoing line breaker is arranged between the low-frequency H bridge and the alternating current power grid, a first end of the outgoing line breaker is electrically connected with the alternating current power grid, a second end of the outgoing line breaker is electrically connected with a first end of a first contactor, a second end of the first contactor is electrically connected with a first end of a first inductor, a second end of the first inductor is electrically connected with the low-frequency H bridge, and the first contactor is connected with a first bypass soft start resistor in parallel; a first direct current breaker and a second direct current breaker are arranged between the low-voltage direct current device and the energy storage end, the first end of the first direct current breaker is electrically connected with the positive electrode of the energy storage end, the second end of the first direct current breaker is electrically connected with the first end of a second contactor, the second end of the second contactor is electrically connected with the first end of a second inductor, the second end of the second inductor is electrically connected with a first phase single H-bridge power module, and the second contactor is connected with a second bypass soft start resistor in parallel; the first end of the second direct current breaker is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker is electrically connected with the first end of the third contactor, the second end of the third contactor is electrically connected with the first end of the third inductor, the second end of the third inductor is electrically connected with the third single H-bridge power module, and the third contactor is connected with the third bypass soft start resistor in parallel; the energy storage end is an energy storage battery pack;
the method comprises the following steps:
selecting a low-frequency H-bridge control mode of the high-voltage alternating current device as a V/F control mode, and selecting a high-frequency H-bridge control mode as a direct-current voltage control mode; selecting a control mode of the low-voltage direct current device as a following control mode, and realizing that active power exchanged between the low-voltage direct current device and the energy storage battery automatically follows active power output by the high-voltage alternating current device through the control; closing a first direct current breaker and a second direct current breaker of the low-voltage direct current device, and charging a second direct current capacitor of the low-voltage direct current device by an energy storage battery pack through all bypass soft start resistors, wherein a second high-frequency H bridge of the low-voltage direct current device is blocked at the stage; when the deviation between the capacitor voltage of the low-voltage direct-current device and the total voltage of the energy storage battery pack is smaller than a set value, the controller of the low-voltage direct-current device closes all bypass soft start resistors of the low-voltage direct-current end to bypass all direct-current circuit breakers, and the energy storage battery pack is connected to the low-voltage direct-current device; the low-voltage direct-current device controller unlocks the second high-frequency H bridges of all the modules of the low-voltage direct-current device and charges the first direct-current capacitor of the high-voltage alternating-current device module through the high-frequency bus; after the high-voltage alternating-current device is charged, unlocking a first high-frequency H bridge of the high-voltage alternating-current device, starting constant-voltage control of the first high-frequency H bridge of the high-voltage alternating-current device, and performing closed-loop control on the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device module; after the average value of the first direct-current capacitor voltage of the high-voltage alternating-current device is stabilized near the reference value, unlocking the low-frequency H bridge of the high-voltage alternating-current device, and putting the high-voltage alternating-current device into operation in a V/F control mode of the low-frequency H bridge; after the whole energy storage converter system is started, the high-voltage alternating-current device is responsible for receiving the voltage and frequency fixed values issued by the upper-level dispatching and coordinating the whole operation of the high-voltage alternating-current device and the low-voltage direct-current device.
4. The control method of the medium-voltage direct-hanging energy storage converter system is characterized by controlling the medium-voltage direct-hanging energy storage converter system,
the medium-voltage direct-hanging energy storage converter system comprises:
the high-voltage alternating current device is electrically connected with the alternating current power grid, and the low-voltage direct current device is electrically connected with the energy storage end, and is electrically connected with the low-voltage direct current device through a high-frequency transformer; the high-voltage alternating current device is in a three-phase star-shaped wiring mode, and each phase is formed by connecting double H-bridge power modules in series; the low-voltage direct current device is formed by connecting single H-bridge power modules in parallel; the double-H-bridge power module comprises a low-frequency H-bridge, a first direct-current capacitor and a first high-frequency H-bridge, wherein the low-frequency H-bridge, the first direct-current capacitor and the first high-frequency H-bridge are connected in parallel; the input end of the low-frequency H bridge is electrically connected with an alternating current power grid, the output end of the first high-frequency H bridge is electrically connected with the input end of a first high-frequency transformer, and the output end of the first high-frequency transformer is electrically connected with the single H bridge power module; the single H-bridge power module comprises a second high-frequency H-bridge and a second direct-current capacitor; the second high-frequency H bridge is connected with the second direct-current capacitor in parallel, the input end of the second high-frequency H bridge is electrically connected with the output end of the second high-frequency transformer, and the input end of the second high-frequency transformer is electrically connected with the output end of the first high-frequency transformer; an outgoing line breaker is arranged between the low-frequency H bridge and the alternating current power grid, a first end of the outgoing line breaker is electrically connected with the alternating current power grid, a second end of the outgoing line breaker is electrically connected with a first end of a first contactor, a second end of the first contactor is electrically connected with a first end of a first inductor, a second end of the first inductor is electrically connected with the low-frequency H bridge, and the first contactor is connected with a first bypass soft start resistor in parallel; a first direct current breaker and a second direct current breaker are arranged between the low-voltage direct current device and the energy storage end, the first end of the first direct current breaker is electrically connected with the positive electrode of the energy storage end, the second end of the first direct current breaker is electrically connected with the first end of a second contactor, the second end of the second contactor is electrically connected with the first end of a second inductor, the second end of the second inductor is electrically connected with a first phase single H-bridge power module, and the second contactor is connected with a second bypass soft start resistor in parallel; the first end of the second direct current breaker is electrically connected with the negative electrode of the energy storage end, the second end of the second direct current breaker is electrically connected with the first end of the third contactor, the second end of the third contactor is electrically connected with the first end of the third inductor, the second end of the third inductor is electrically connected with the third single H-bridge power module, and the third contactor is connected with the third bypass soft start resistor in parallel; the energy storage end is an energy storage battery pack;
the method comprises the following steps:
after receiving the shutdown instruction, the high-voltage alternating-current device controller disconnects an outgoing circuit breaker of the high-voltage alternating-current device to cut off an external load of the energy storage converter system; after the outgoing line breaker of the high-voltage alternating current device reaches the separated position, the high-voltage alternating current device controller coordinates the high-frequency H bridge of the high-voltage alternating current device and the low-voltage direct current device to be synchronously locked, and the high-frequency bus is in power failure; after the high-frequency H bridge of the high-voltage alternating current device and the low-voltage direct current device is locked, the first direct current breaker and the second direct current breaker of the low-voltage direct current device are disconnected, the energy storage battery pack is withdrawn from operation, and the low-voltage direct current device is stopped; after the low-voltage direct-current device is stopped, the low-frequency H bridge of the high-voltage alternating-current device is locked, and the whole energy storage conversion system is stopped.
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